00:00:00MEJIA: This is Robin Mejia here with Makato Kuro-o in his office at U.T.
[University of Texas] Southwestern Medical Center on March 6,  for the
first day of the Pew [Scholars Program in the Biomedical Sciences] oral history
KURO-O: Thank you. Hi. How are you?
MEJIA: Good. It looks like we're picking up just fine here. So I thought we
would start this at the beginning. Could you tell me where you were born and
where your parents and family are from?
KURO-O: Okay. I was born in Tokyo in 1960. My parents [Masahiko Kuro-o, Nobuko
Kuro-o] are in Japan, and my wife is Kumiko Kuro-o. She was born in 1961 in
MEJIA: Can you just tell me a little bit about your parents, what they were
like, what they did?
00:01:00KURO-O: Okay. My father [Masahiko Kuro-o] was an engineer working on designing
some air-conditioning systems or something like that. He graduated from Tokyo
Industrial University. It's also in Tokyo, but he is originally from a little
bit north, northern part of Japan. My mother [Nobuko Kuro-o] was also from
there. My father is currently--let me see--eighty years old, and my mother is
five years younger, so she is seventy-five, if I remember correctly.
I have one sister [Atsuko Rakuman], an older sister. She is four years older
00:02:00than me. I am now forty-six, so she should be fifty. She got married and has two
children, a boy [Satoshi Rakuman] and a girl [Kaori Rakuman]. They are not a boy
and a girl, actually; they are in college right now, so they are pretty much
grown up. I have no kids. That's my family.
MEJIA: And did your sister stay in Japan?
KURO-O: Yes, they live in Japan. They are very close to our parents.
MEJIA: Are your parents both from the same community? Did they move to Tokyo?
MEJIA: What brought them to Tokyo?
KURO-O: My father got a job in Tokyo after graduating from the university.
Actually, the university was in Tokyo. When he graduated high school in his
town, then he moved to Tokyo to go to university. So since then, he stayed in
00:03:00Tokyo and got a job in Tokyo. But when he got married, he just went back to his
hometown and he got married with my mother there. After they got married, they
both, again, came back to Tokyo. It's not very far, just a bus [ride] down to
Tokyo. It's just two hours by train.
MEJIA: Probably better work opportunities?
KURO-O: Yes. Yes, better work opportunities in Tokyo.
MEJIA: They had you after they were both in [Tokyo]?
MEJIA: So you were born in Tokyo after they had both ended up there?
KURO-O: Yes. Yes. Right. Yes. I think I was born six years after they married,
00:04:00maybe. Yes, something like that.
MEJIA: Okay. What level of education did your mom have?
KURO-O: My mother just had college. The system was very different at that time.
It was before World War II, but around World War II. She graduated college, and
she actually had never worked. After graduation, she got married with my father,
and then she never worked, just doing the housewife, housekeeping. That's rather
traditional style in Japan, actually.
MEJIA: I think your microphone's gone hiding there.
00:05:00KURO-O: Oh, yes. Okay. Maybe this is not good. Better?
MEJIA: That looks great.
KURO-O: Yes. Okay.
MEJIA: And to be an engineer, was that an advanced degree or a college degree?
KURO-O: Not college. He graduated from a university program. I'm not so familiar
with that. That is a different system, so it's probably similar to the
graduation of university for a B.S. [bachelor of science degree] He didn't go to
00:06:00graduate school, but he just graduated university. Yes.
MEJIA: Can you tell me just a little bit about your neighborhood?
KURO-O: In Japan?
MEJIA: In Japan, yes.
KURO-O: Okay. Well, I lived in the north central part of Tokyo, a little bit
urban area of Tokyo. What do you mean by neighborhood? Just what kind of people
MEJIA: Did you have friends in your neighborhood? Did you go to school close by?
KURO-O: Sure. Yes, sure. I went to elementary school and junior high school in
00:07:00the local junior high school and elementary school. Many friends at that time
were also living very close by, so it was a local community. Some very clever
boys and girls can go to the more high-ranked school, but it's very expensive.
My parents are not very rich, just average income, and so I just went to the
local schools. After graduating junior high school, I didn't in high school.
Anyway, we just stuck in the local community.
A good thing in Japan is no huge difference in income. In the [United] States,
00:08:00rich people are very rich, and poor people are sometimes very poor. But the good
thing in Japan is there's not very much difference in the income, so the way of
life is very similar. That was a good thing for me, in a way. That was the
community I was in growing up. Nothing in particular, actually.
MEJIA: So what you're saying is, your friends in the area, even though your
families were different, it wasn't the same differences.
MEJIA: Did you have any particular interests in school at that time or just
everything, like a lot of kids are?
KURO-O: Well, yes, maybe I'm not very different from others, but I'm interested
00:09:00in science rather than literature. Yes, science or chemistry or physics or
something like that. I don't know why. My father was an engineer, so that might
have had some influence.
MEJIA: Did you talk about engineering with him, or his work?
KURO-O: No, not very much. I really respected his work, because he didn't design
small air-conditioners. Actually, his major was to build up a building, or
storehouse to keep the imported meat, or some big, huge structure. His work
00:10:00includes the air-conditioning system in the Tokyo Station. Of course, it's only
a part of it, but he is very proud of that. The good thing for such kind of work
is you can actually look at what he did. So that impressed me a lot. He didn't
talk much about science, but maybe I thought, oh, my father is great. [laughs] I
had a little bit of the favor of science or chemistry, physics, or such kind of area.
MEJIA: Even before high school?
KURO-O: Right. I think so. I think so.
MEJIA: Any particular memorable classes or teachers or projects?
KURO-O: Yes. Is it okay if I talk about high school?
00:11:00KURO-O: Okay. In high school, I had two teachers, very impressive for me. One
taught physics [Mr. Takahashi] and the other taught chemistry [Mr. Yoneyama].
Actually, I don't remember very well about what he taught me, but I was
impressed with their personalities. They were really strict, and many students
were afraid of them, but they were really, in a sense, very kind if I had any
questions. If I asked any questions, they were very enthusiastic about answering
00:12:00the questions. I actually forgot what I asked them, but they were really
Actually, the teacher I was most impressed with in my early education, I met him
in --what do you say?--the preparation school. I spent one year after graduating
high school until I got into Tokyo University. There is one year blank because
in Japan, the entrance examination to the university is very difficult
sometimes. I was not accepted in any school just after I graduated high school.
00:13:00So I had to prepare another year, study hard and get a high score in [the]
During that period, the students usually go to some school that teaches how to
increase the score. It's kind of a technical school, but people usually don't
expect so much about the teaching, about the personality. But one of the
teachers I met there was, again, a physics teacher [Mr. Sakama], and he was
actually a professor at another university, the University of Saitama in Japan,
and he spent some time teaching dropped-out students like me. His lectures were
00:14:00really excellent. He taught us--I don't know how to say it in English--it was
like Newton's classical [physics]. What do they say?
MEJIA: Classical physics?
KURO-O: Classical physics, yes. At that time I had a little bit of confusion
about physics and how to understand physics, but he introduced mathematics to
explain how classical physics works. At first I couldn't understand anything,
and in the meantime, his lectures were very nice. I finally understood
00:15:00everything. So it was really my first encounter with scientific thinking, I
think. This was actually a very classical formula. Of course, I learned this
when I was in high school: first rule, second rule, third rule, something like
that. But I just memorized it [the rules], and I didn't know where this [rule]
came from; I didn't know about the principle. I didn't know the principle at
all. But he used mathematics to explain this, and he explained everything just
00:16:00on paper without any experiment. During the lecture, I understood that science
is built up from very simple principles, and everything can be deducible from
very few principles. To find those few principles is very difficult, maybe, but
I thought it's a very beautiful system, and I was very impressed about how
beautiful the physics system is. Probably that is the most direct reason why I
wanted to devote myself to science. It's really impressive.
Usually, in preparatory school, nobody expects that. They just expect a
00:17:00technical thing: how to answer these kinds of questions or programs or something
like that. Usually it's not a very fruitful year, just preparing to go to the
university. People expect such things in the university, actually. But, yes, I
was lucky. So that was the most impressive teacher for me.
MEJIA: I'll actually want to come back to that, because it sounds like it was
probably an important period for you. But if we could step back for just a
minute, you said you went to the local grade school and junior high or equivalent.
MEJIA: So what happened next? How did you end up deciding, or your parents
deciding, or how did you end up going to a different high school? Can you talk
00:18:00KURO-O: There are several different high schools we can choose from, and of
course there are several local high schools. There are some local high schools
that are really good schools, so many students just go there. But there is
another area; it's a private high school. There are many good private high
schools, but they are usually far from where we live, so you have to spend one
hour to commute there. Another way is to go to not a local but kind of national
school, something like that. So there are three ways: a local high school, a
00:19:00private high school, and national high school. It's run by the government. There
are three ways.
I went to the national school, partly because it's cheap. Actually, it is really
difficult to get into. The entrance examination is really difficult. So maybe
only the top 1 percent of students can enter this school. I was really lucky; I
passed the entrance examination. So that was really to my advantage for the
00:20:00education. Of course, the teachers were really nice. As I said, I met two good
high-school teachers, the physics and chemistry, there. So that school was very
nice, and many students in the Tokyo area come to this school.
MEJIA: Two quick questions. Is that somehow associated with the university, that school?
KURO-O: No, it's not associated with the university. But, of course, some
private schools have some association with the university. But in my high
school, there was no particular association.
MEJIA: At this point, I guess, how important was education in your family at
home? Was that part of a driver, or was this more of a personal thing from
inside you, or a mix?
00:21:00KURO-O: My father graduated university, so naturally they expected me to
graduate from university. Actually, many Japanese students at that time, maybe
more than 50 percent of the high-school students, went to the university.
Recently the rate is much higher, maybe 70 percent. You might not believe that,
but in Japan, university education is relatively cheap. So many high-school
students can go to the university. But at that time, the rate was probably
around 50 percent or so. But anyway, my father graduated the university, so I
thought of course I should go to the university. I didn't think about not
getting higher education.
00:22:00When I graduated high school, I began to think about being a medical doctor,
probably because my parents suggested it to me, not forced me. But a doctor was
a good occupation. So maybe I was gradually educated by them to be a medical
doctor. But I also think, of course, a medical doctor is a very important
occupation, and it's a very respectable occupation. At that time, I really
wanted to be a hard-core clinician.
MEJIA: A hard-core what?
KURO-O: Clinical doctor, so look at patients and cure disease. At that time, I
00:23:00didn't know anything about medicine, but I wanted to be a good doctor.
MEJIA: Did you think about research at all at that point?
KURO-O: No, not at all. For a young high-school graduate student, when I say
doctor, that meant clinical doctor. No idea about research and how research is
going on, I had no idea at that time. I wanted to be a medical doctor, so I
entered medical school in Tokyo University.
MEJIA: So you applied once out of high school and again out of the preparatory school?
KURO-O: Yes. I spent one year, and then the next year I was successful. It's a
00:24:00really difficult entrance exam, especially medical school in Tokyo University.
It's really tough. In the United States, I heard that entrance is not so
difficult, but graduation, to graduate a school is really tough, especially a
good university. But in Japan, it's different. To get into a good university is
really tough. It's very severe competition at the entrance. But once you enter
school, you don't have any difficulty graduating if you just study, obviously.
MEJIA: I know I asked you to clarify this earlier, but for the recording, too,
can you explain how the system works there, which is a little bit different than
in the U.S. [United States]?
KURO-O: In the university. Okay.
MEJIA: Yes. Because you already knew out of high school that you were applying
00:25:00to a medical program, so could you explain how that works?
KURO-O: Yes. Once we entered the university, we spent two years getting some
basic education about any science, like biology, of course, and any area of
science, like philosophy or statistics or mathematics, any kind of science, not
very in depth, but just getting an idea about what the, say, philosophy looks
like or something like that. We spent two years learning foreign languages there.
In that elementary two years, all students were in the same class. There were no
00:26:00medical students. Everybody received the same lecture, the same education. But
after two years, we were divided into specialties. In my case, of course, we
went to the Department of Medicine, and the special education started: anatomy,
physiology, biochemistry, the basic science first. Then we spent two years for
that, and then another two years for clinical stuff like internal medicine,
surgery. We rotated through the hospital, university hospital, and just looked
00:27:00at patients or just talked with patients. It's probably very similar in the
United States. So two years of basic education, two years of basic research
education in medicine, and two years for clinical medicine, and then we
graduated after six years of education.
MEJIA: And those first two years, when you say you're all together, is that
everybody who's going to go into the medical school, or is that everybody at
Tokyo University? Because the university looked huge when I found it on the website.
KURO-O: Yes, right. Right. Exactly. There are probably more than three thousand
or four thousand students in a class, and only ninety people are for medical
00:28:00school. Let's say one thousand students are for other areas. Some are law
school, some are economics, or something like that.
So the high-school students apply for each area first. So if you want to go to
law school in the future, the high school student will apply for the law-school
course, but in the initial two years, they are all mixed, that is, educated in
the same way. But after that, they go to the law school they applied for at the
entrance examination. So it might be a little bit different system, maybe.
MEJIA: So it's two years of essentially general education?
00:29:00KURO-O: Right. Right. Is it like that in the United States?
MEJIA: No. It varies. Most universities have some what they call either
comprehensive or general education requirements, but you wouldn't necessarily
all be taking them together. By the end of your four years you have to have
finished this much general stuff in addition to whatever you choose for your
major, and then your major will set its own requirements.
KURO-O: I see. Yes. There is some flexibility, but essentially we go through
these steps. Especially in medical school, there's no room to choose. All the
classes are mandatory. But anyway, it's really a long education, six years.
00:30:00MEJIA: Did you continue to live at home, or did you move for school?
KURO-O: I commuted from my house. It's just one hour from my house. So I stayed
with my parents. I just went to the university from my parents' house. I got
independent from my parents after I graduated from medical school. So it was
cheap for my parents. I didn't eat up their income. The good thing is, at the
University of Tokyo, tuition is very cheap, actually. It's only maybe one or two
00:31:00thousand dollars for a year, everything, including everything. Of course,
private school is really expensive. So maybe my parents couldn't afford that.
There are many good private medical schools, but tuition is maybe a hundred
times more expensive, really different. So maybe only very rich people, like
doctors' families, can afford that.
But the good thing is, all the national universities were very cheap. Recently,
it's not so cheap, but at the time. I had no choice other than to go to the
00:32:00national university. But especially Tokyo University was good because it's a
really good school, and I didn't need to move. It's in Tokyo, and I could get
there in only forty, fifty minutes. So that's one of the reasons why I chose the
University of Tokyo.
MEJIA: They have a good transit system, right?
KURO-O: Yes, right. Yes, a very good public transportation system.
MEJIA: I do want to talk more about your education in a minute, but now I'm just
curious, did your sister go to university, too?
KURO-O: Yes, she went to pharmaceutical? What is that in English?
MEJIA: Same word. Same word: pharmaceutical.
KURO-O: Yes, same area. She went to the private pharmaceutical university, and
00:33:00she graduated. Currently she is a housewife, but she had some part-time job with
a pharmaceutical company that was over there. So, yes.
MEJIA: Okay. We'll go back to your schooling, then. As you were getting into
medical school, any particularly inspiring classes there that helped you pick a direction?
KURO-O: Yes. Actually, I was interested in cardiology. It's because my father
had a myocardial infarction when I was in the second year in medical school. At
00:34:00that time, I still had no education about clinical things. He survived. But that
was a very good opportunity for me to get into the cardiology area a little bit
more. There was a lecture on myocardial infarction, and a professor Yoshio
Yazaki taught us about myocardial infarction. Actually, I was very impressed
with his talk because there are several ways to diagnose myocardial infarction:
00:35:00electrocardiography, of course; and there are several markers in the blood.
Usually at the time people used creatine kinase as a marker for myocardial infarction.
At that time, the professor found a new marker for myocardial infarction, and he
tried to apply that marker to the clinical application. I was impressed with his
talk, and I just visited his laboratory and spent some time in his laboratory to
work on the basic aspects of myocardium. His laboratory is, of course, a
clinical laboratory, but he's also very interested in the basic aspects of
00:36:00myocardial contraction and myocardial differentiation and things like that. So I
spent some time in his lab and did some basic research in his lab. Fortunately,
I got a good publication there when I was still in medical school. That was the,
maybe, first involvement in basic research for me, and very fortunately, I could
get a good paper published. Yes, I was still interested in clinical stuff, but I
was also getting involved with basic research. Actually, I didn't know how basic
00:37:00research was actually going at that time, so it was very, for me, a good
opportunity to experience what was really actually going on in the basic
MEJIA: So did you just approach him after a lecture? How did you go from hearing
him and being interested, to getting to work in his lab?
KURO-O: Actually, it's a very good system in Tokyo University. During summer
vacation of the second year as a student, we actually had extra a one month
longer summer vacation than the other years, from the beginning of June through
the end of August. The medical students in the second year are encouraged to
visit a laboratory, any laboratory or any clinical department, to participate in
00:38:00some way in the basic research activity or some clinical activity.
Almost all students use that activity and spend the entire summer in a
department or laboratory. Actually, it was just before the summer vacation, so I
spent that summer vacation in his lab.
There is a coordinating committee so the laboratory can accept such students by
applying to the committee, and students who want to do some research can, of
course, apply to the committee, and the committee matches them to each other. So
there is such a system there. I took advantage of the system, and I went to his
00:39:00lab and did some very basic research on myocardial differentiation.
MEJIA: That was right after you finished your first two years of medical classwork?
KURO-O: Yes. Right. Right. At the time, I didn't know very much about clinical
things, but it was really a good experience for me. In his lab I got some idea
how basic research was going, and I really liked the basic research laboratory.
But I still had two years to go to get my M.D., so I continued medical school
Maybe 90 percent of students went to some clinical department for two years. It
00:40:00was a kind of internship or something. And only 10 percent of students went to
basic research. It was probably because we didn't have a good opportunity to be
exposed to the basic research laboratories, although there were some
opportunities in summer vacation in some particular years. But after that, we
didn't have direct access to the basic research laboratory. So at that time, 90
percent of students went to the clinical department, and only 10 percent
00:41:00directly went to basic research.
MEJIA: Is there an option, for those final two years, to be in a basic research department?
KURO-O: Yes, there is an option, but almost all students take the examination to
get their medical license, and after that, we can choose which way to go.
MEJIA: So you, for those two years, were one of the majority that went into a
KURO-O: Yes. Actually, I went to the internal medicine cardiology department,
and yes, I was really a clinician in the first, say, five years. I rotated in
several hospitals and worked for CCU [coronary care unit] or looked at lots of
00:42:00patients with acute myocardial infarction or something like that and spent five
years. But it's actually a tradition in Japanese medical society to do some
basic research and get a Ph.D. At that time I was a cardiologist, but I was also
interested in the mechanism of hypertension. So after I got the Ph.D., I had a
chance to get some support from the government, and I could spend some time at
MEJIA: Okay. Can I jump in for a minute?
KURO-O: Yes. Sure, sure.
MEJIA: So you had two years that are like a residency here, it sounds like?
00:43:00KURO-O: Yes. Right.
MEJIA: Can you describe on the tape at what point you decided to get a Ph.D.,
and then how that works, since you had already gotten your M.D. It's a different
system. You had said that it's not like an M.D./Ph.D. program in the U.S. Can
you describe how that worked?
KURO-O: Right. Okay. So after graduation and also during the two years'
internship, it was too busy to do basic research, so I just focused on clinical
work. After finishing my internship, I continued patient care, but I also
00:44:00studied some basic research, this time smooth muscle cell differentiation. It's
a little bit complicated. Okay. So one, two, three, four years of five, six.
After graduation I spent two years as an intern, and actually, just before I
graduated from medical school, I had a chance to visit the University of Vermont.
00:45:00Actually, one of the postdocs [postdoctoral fellows] of the laboratory where I
spent my summer vacation visited the University of Vermont for four years.
Actually, I stayed at his house and had a chance to look at how the research was
going on in the United States. It was only two months' experience, again during
summer vacation. His name was Dr. [Ryozo] Nagai. He's a key person for me, Ryozo
00:46:00Nagai. Actually, now he's president of Tokyo University Hospital. He's very
influential in the Japanese Medical Society right now. When he was a postdoc, he
spent some time at the University of Vermont, and I had a chance to be there for
two months in summer vacation. He liked me, and I liked him, so our research
interest was very similar. He was working on smooth muscle cell differentiation
at the time.
But I had to go back to Japan and finish my school program and get a medical
license, but he told me that, "When I'm back in Japan, let's work together
again," something like that. So he went back to Japan, maybe when I was in the
00:47:00fourth year. After finishing medical school and spending some time in the
hospital, he came back to Japan and asked me to come back to Tokyo University.
He was starting his laboratory at Tokyo University, so I joined his lab. That
was actually a major change in my career. Of course, in Tokyo University you
have to look at patients too, but you can spend more time in research activity,
basic research activity.
So we worked together and get some good publications about the smooth muscle
00:48:00cell differentiation. So he was the person who brought me back to the basic research.
MEJIA: You know, I'm going to actually flip this really quick before my next question.
[END OF TAPE 1, SIDE 1]
MEJIA: This is Robin, and we're now on side two, continuing on the first day of
So you were saying, I guess, it looks like your second year after you finished
your internship, so your fourth year of working as a doctor, is that right?
MEJIA: That brought you back to Tokyo University to do research.
MEJIA: So at this point you have your M.D. How are you funded at this point?
KURO-O: Well, during the internship, the university hospital can pay our salary,
but after finishing internship, we have to get some money outside of the
00:49:00hospital. Anyway, I worked for some clinics somewhere in Tokyo and get some
money just for pay for my bills. But I spent the rest of the time to take care
of the patient in the university hospital and spend some time to do basic
research. Many M.D.'s just finish internship in Japan, did the same way, so it's
a little weird, but it's a tradition in the Japanese medical society.
MEJIA: That makes sense. So then you're back at the university and you're doing
00:50:00research again. When you came back, did you know you were going to pursue the
Ph.D., or was that a decision you made there?
KURO-O: Right. All M.D.'s want to get Ph.D., actually. It's sometimes difficult
because to get Ph.D., M.D. have to spend significant amount of time to basic
research, but it's usually very difficult when they are looking at the patient.
But when you stay in the university, we can somehow do that, because a lot of
doctors there and they can share their duties and make some time to focus on
basic research for a while. So it is essential for M.D.'s to stay in the
00:51:00university if they want to get Ph.D., so I stayed in the university and spent a
couple of years for basic research, but I cannot spend 100 percent of my time to
research. Maybe, say, 50 percent of my time to research and 50 percent of time
to looking at patients. But somehow I got some publications and combined them to
a big article.
MEJIA: Like a dissertation?
KURO-O: Yes, dissertation, and applied to the committee and my Ph.D. was
approved in 1991. So it took six years, maybe, after I graduated the medical
school, to get the Ph.D. At that time I spent maybe more than 50 percent of time
00:52:00for patients' care. It's not so bad for me, actually. Anyway, I got Ph.D. in 1991.
MEJIA: I think you said before we had the tape on that because you had completed
an M.D., it basically was just the dissertation at that point.
MEJIA: You didn't have to go do another series of--
MEJIA: Okay. Can you talk a little bit about the research interests you had at
that point and what you worked on with Dr. Nagai?
KURO-O: Yes. So Dr. Nagai's main research interest was how smooth muscle cells
in vessels change during the arteriosclerosis or hypertension. So my research
00:53:00interest was also similar, and I wanted to know the mechanisms, how hypertension develops.
So at that time a new technology, transgenic mouse technology, has become
available, so he and I wanted to introduce that transgenic mouse technology to
his lab, so I went to another laboratory to learn that transgenic mouse
technology. The institute I went was National Institute of Neuroscience in
Japan. I tried to make transgenic mice that overexpress an ion channel called
sodium proton exchanger, because at the time the overexpression or activation of
00:54:00that ion channel might be related to blood pressure elevation. So I wanted to
make transgenic mice that overexpressed that particular ion channel and wanted
to ask whether they develop hypertension. So I spent--I forgot how many I spent,
but I spent a couple of years to make transgenic mice and analyze it there. As
we expected, they developed hypertension when we load sodium to them.
MEJIA: So you developed mice models yourself at the institute?
MEJIA: How long were you at the institute? Did you then go back to the lab and
work on that?
KURO-O: Well, actually, I was not allowed to spend 100% of my time for the
transgenic mouse experiments. I looked at patients in Tokyo University and I
00:55:00went to the National Institute of Neuroscience after I finished my clinical duty
there. So it's really tough. So I worked literally fourteen, sixteen hours a
day, seven days a week, for several years. It was very tough for me, but it was
really good chance for me. At the time, transgenic mouse technology not so
popular. It was rather regarded as a high-tech technology. Of course, basic
research, I can do that, but nobody thought that clinical researcher can do
that, but it was good for me to get the technology and we can get the expected
00:56:00result. But what was good for me was I got some byproduct in that project, and
that's brought me here, actually, the science project, so it was really lucky
Okay. So the way you make transgenic mice, you inject gene fragment into mouse
egg, and the gene fragment get integrated into mouse genome, and of course we
expected that the integrated gene will be expressed and generate more protein
and cause some disease or phenotypes in the mouse, but it doesn't usually go
00:57:00like that. Okay. So the gene you injected will integrate into the mouse gene,
but sometimes it's not expressed; it's just sitting there and do nothing. So
it's a very common phenomenon when you do the transgenic mouse experiments.
Actually, I made thirty independent transgenic mouse lines, but only three of
them expressed the integrated transgene.
So using those three lines, I found that the overexpression of the gene caused
hypertension. But the rest of 27 strains had transgenes integrated into the
genome, but the transgene did nothing; just sitting there. But it's
theoretically possible that the integration of the transgene could destroy the
00:58:00endogenous mouse gene at the integration site, and if the transgene accidentally
integrated into one of the very important genes for the mouse, then the mouse
may develop totally unexpected phenotype, not because of expression of the
transgene, but because of disruption of the endogenous mouse gene. That
phenomenon is called insertional mutation. So I just examined the rest of the 27
transgenic mouse lines, that did not express the transgene, and found that one
of the transgenic mice developed disease similar to aging, human aging. It's
00:59:00just an accident.
So nobody can control where the transgene is integrated, so what we can do is
just inject the gene fragment in the mouse egg and let them integrate the
transgene. So the transgene will be integrated randomly into the mouse. But it
could accidentally hit the endogenous mouse gene and disrupt it. Actually, this
kind of phenomenon has been known for years, but it really depends on luck. So
if you get some interesting mutant, we can pursue that, but we cannot do that on
MEJIA: So at the time when you, I guess, were first in the lab, I looked through
01:00:00your publications, it looked like at that point you were still publishing on hypertension.
KURO-O: Yes. Right. Right.
MEJIA: And [unclear] stuff. So you kind of pursued that [unclear] first.
MEJIA: At that point did you get the mutant mouse?
KURO-O: I noticed that I got mutant maybe about 1992 or '93. Just after I got
the Ph.D. I went to the National Institute of Neuroscience. One year after I got
several lines of transgenic mice, so I noticed there's some very real mutant
there, maybe '92 or something like that.
MEJIA: Okay. I definitely obviously want to come back to that, but I'm curious,
because you were just describing your fourteen-hour days, when did you meet your wife?
01:01:00KURO-O: I think it was hard for her. Anyway, but we have to do that because
doing both clinical duties and basic research is too greedy, and I never do that
again, but I knew that it won't continue forever, just for a couple of years.
MEJIA: Did you know your wife prior to that period? I know you weren't married
yet, but did you knew each other prior to that period?
KURO-O: I'd leave the house around seven a.m. and be back at twelve midnight,
01:02:00something like that, but, you know, at the time Japanese people, many Japanese
people are workaholics, so it's not very unusual. It's pretty unusual, but not
very unusual, actually. My wife is rather conservative type of woman, and she
knows that all my father's generation works very hard, very long to recover from
the damage of World War II, so many people in my generation looked at the
parents working very hard for a long time, so for us it's not very unusual, but
still shouldn't be very hard. I don't know the younger generation in Japan can
01:03:00accept that, anyway.
MEJIA: Did you two [his wife, Kumiko Kuro-o, and he] know each other before this
really crazy period?
KURO-O: Yes. I got to know her when I was in the last year of medical school. We
didn't get married during the internship because I knew it was a really crazy
period. I think in the [United] States internship is a crazy period. So we
waited to get married after I finished the internship.
Yes, she understood very well what I had to do in that particular period of my
01:04:00career, and her father is also hardworking, a very typical Japanese. I really
appreciated that at that point. But we didn't have so very difficult a time to
get through that hectic period.
MEJIA: And she was an accountant?
KURO-O: Yes. She had a part-time job at that time, and she could spend some time
outside of the house. If she had been a housewife at the time, she might have
gone mad. [mutual laughter] She also had work, so we both were pretty busy. So
that was okay.
MEJIA: And you two lived in Tokyo still at that point?
01:05:00KURO-O: Yes. Yes. We never were apart.
MEJIA: At that point, then, you go back to basic research and prepare a dissertation.
MEJIA: Once you have a Ph.D., what options does that open up? You described
supporting yourself and then being able to do the research. What options does
getting a Ph.D. open up?
KURO-O: Yes. After getting the Ph.D., there are actually still essentially two
options. One was, of course, continue looking at patients and doing basic
research at the same time, basically continuing the lifestyle. But of course,
01:06:00once you get a Ph.D., you have to train the younger researchers. There is some
change in the role, but essentially you can go along in the same way. That's one choice.
Of course, you can choose to do a completely different thing like I did: intern,
go to basic research. But it's not very common, I think, because usually, once
you drop out of the academic career in Japan, it's very difficult to get back again.
01:07:00I think the United States is very unique because actually, in Japan, age is a
very influential factor to determine one's position. So usually, let's say, the
Ph.D. in his forties cannot start as an instructor. Usually they expect to be an
associate professor. There is a very strict hierarchy in the Japanese medical
community, and postdocs [postdoctoral fellows] may be, at most, in their
thirties, assistant professors and associate professors in their forties, for a
01:08:00professor, fifties, and usually it's not very common to work fifty years old as
a postdoc under the supervision of a thirty-year-old assistant professor. That
couldn't happen in Japan.
Then, naturally, as you age, you have to get a certain position. So that's how
it's very difficult to change a career in the middle of the career. Let's say,
if you spend years as a clinical doctor and as you get to forties, then it's
real difficult to change one's career to a basic research area, because in your
forties, people expect that they should be an associate professor who already
01:09:00has his own lab. So he cannot start from scratch, like a postdoc or a student.
Anyway, so when I got the Ph.D., I was thirty-one. So I had to decide which way
to go. If you stay in the clinical department, yes, that's one way. But if you
want to go to basic research, I had to decide right now, immediately, because if
I spent several years in the clinical department, I would be thirty-five,
thirty-eight, and at that age maybe I could not transfer to the basic research
01:10:00area because I had to be assistant or associate professor at that time.
I was thirty-one. This was probably the last chance to change my career in
Japan, and I really wanted to work on that mutant I found. The mutant looks
aged. It's theoretically possible that the integration of the transgene could
destroy the endogenous mouse gene at the integration site. That phenomenon is
called insertional mutation. Because of the transgene mutation, it could
accidentally hit the endogenous mouse gene. So I really wanted to understand
what gene was disrupted and what gene disruption caused the similar to aging in
humans. I could identify the gene disrupted in that particular mutant. That gene
[Klotho] could be an aging suppressor gene, because if you disrupt it, animals
01:11:00get old very quickly. If you could identify that gene, the function of that gene
could be suppressing aging. That could be a huge discovery. I decided to pursue
that area. I decided to spend my time and focus on the identification of the
gene disrupted by the transgene integration. So I moved to the National
Institute of Neuroscience, where I developed the transgenic mouse and spent time
identifying the gene.
MEJIA: Is this like a postdoc arrangement?
KURO-O: Yes, as a postdoctoral fellow.
MEJIA: So you were funded?
01:12:00KURO-O: Yes. I was funded from NIH [National Institutes of Health] in Japan
[National Institute of Neuroscience], so financially it was fine. I was paid and
got a grant, so I was able to somehow survive, for several years, at least.
MEJIA: And you were able to just do research at this point?
KURO-O: Yes. At that time I spent 100 percent of my time doing basic research.
Actually, identifying the mutated gene in the mouse genome is very laborious
work, so I knew that I couldn't do that doing clinical duties together. So I
01:13:00gave up the clinical duties, and I left Tokyo University and moved to the
MEJIA: So you were able to answer your original questions using the mice, that
KURO-O: Right. Right.
MEJIA: And is it fair to say you were most interested at that point in your
strange mutant, or were you still working with those other ones?
KURO-O: I was still working on that genome, okay? So it took maybe four or five
years to identify the gene, and I named the gene Klotho after the Greek goddess
who spins the thread of life. Anyway, I could identify the Klotho gene, and I
got a good publication about the Klotho.
01:14:00MEJIA: You got a very good publication.
KURO-O: Well, it was very lucky for me, and that paper actually brought me here
[University of Texas Southwestern Medical Center].
MEJIA: Which I want to get to, definitely. Could you just maybe talk a little
bit more about what it was like at the institute [National Institute of
Neuroscience] in your postdoc? Were you working under somebody in the lab,
somebody here? How independent were you?
KURO-O: My position was postdoctoral fellow, but the reason why I first visited
that institute was to learn transgenic mouse technology. There was no particular
scientific supervisor, actually. I just wanted to learn how to make a transgenic
01:15:00mouse. And of course I brought my project, both of my projects, to make
transgenic mice that overexpress sodium-proton exchange. So, scientifically I
was totally independent, but financially I had to borrow some money to get the
reagents necessary to do the research or borrow some equipment or space to carry
out the research.
I belonged to the molecular genetics department there, but I received no salary
from them. I provided my entire grant to them to get some reagents from the
grant, and of course, it was not enough to support everything I spent, so I
01:16:00borrowed some reagents, many from them. So financially, they contributed very
much to my work. Of course, the results we shared, the office shared with them.
I was very happy to work with them.
MEJIA: Can you describe just a little bit what the process is? You know you've
disrupted a gene somewhere, and you're interested in it, but what do you do?
KURO-O: What I actually did to isolate the gene?
KURO-O: Okay. In the mouse genome, the transgene was integrated somewhere. What
01:17:00I had to do was identify the gene just around the integration site. So the first
thing I did was to isolate the genes close to the integration site. It's easy to
say but difficult to do. Anyway, I can somehow identify the genome sequence
adjacent to the integration site.
And the next step is to compare this region to the original mouse genome and
find out what is different between them. Sometimes the insertinal mutation
occurs frequently than we thought, because some people say that 5 percent or 10
01:18:00percent of all transgenic mice show some kind of phenotypes related to the
insertional mutation. It's not a very rare phenomenon, but people never pursued
or people never tried to identify the gene disrupted by the transgenic division
because integration of the transgene usually results in severe destruction of
Usually it's very difficult to identify what gene was lost or what mutation was
induced because of the huge destruction of the overall chromosomal architecture.
But I was again lucky because transgene integration generated a very tiny
deletion, simple deletion, at the integration site, and in other parts, it was
01:19:00almost intact. So it was not easy, but relatively easy to identify what was
disrupted in the mutants.
Anyway, we found out that the transgene integration produced a small deletion in
the original mouse chromosome. It's like this. There is a mouse genome and there
is the mutation of the transgene, and there is a small deletion here. Something
is lost here. So maybe there might be a gene here, and the rest of this gene
could cause the aging-like phenotype. So I just tried to identify it. There
01:20:00might be some gene around here, and I can find one gene very close to this
deletion site, and actually, it later turned out to be a Klotho gene.
But the difficult thing is what do we know about. The transgene was integrated
here and this part is lost. That's fine. You find the gene here. That's fine.
But there might be several genes around here, and deletion might somehow
influence the expression of other genes, and these genes could be the true cause
of the aging-like phenotype. We cannot exclude that possibility, but we cannot
search everything around here. But anyway, I could identify one gene, and this
01:21:00gene expression was very much suppressed in the mutant. So that gene was a very
strong candidate for the responsible gene of the aging-like phenotype.
Okay. If that gene is indeed responsible for all the aging-like phenotypes in
the mutant, we may be able to rescue that aging-like phenotypes when you bring
the gene back to that mutant. So we did it, and indeed, the aging-like
phenotypes are completely rescued. So we were able to conclude that this gene I
isolated was indeed responsible.
MEJIA: So you reintroduced the gene through a vector?
KURO-O: Right. Yes. It's actually a long way, so to identify the gene, it took
01:22:00maybe two or three years, and to prove that this gene is indeed responsible for
the aging-like phenotype, we had to make, again, transgenic mice that
overexpress this gene and cross them back to their mutant background and see
whether the transgene can rescue the phenotype. It was a long study, but it was
successful, so I was pretty happy to get this data.
MEJIA: When did you name the gene?
KURO-O: Well, when I isolated this gene. It was maybe '96 or '95, and I spent
another year to prove that this is indeed the age suppression gene, so my
01:23:00publication was '97 or maybe '95 or something.
MEJIA: The name is elegant. I'm just curious, did it just come to you? How did
KURO-O: Actually, my ex-boss, the chief of the molecular genetics department in
the National Institute of Neuroscience, his name is Dr. [Yoichi] Nabeshima, and
he was not directly involved in the scientific part of this project, but he was
very curious about what I was doing. He read some books on Greek myths, and he
picked out that name. Klotho in Japanese sounds a little bit like my name.
01:24:00MEJIA: Oh, I hadn't thought of that.
KURO-O: Especially we cannot distinguish the sounds of L and R. Japanese has no
TH, so in Japanese, Klotho and Kuro-o sound pretty similar. That's why he picked
out this name, maybe.
MEJIA: Up to that point you had some pretty good success with publications, but
this was obviously a breakthrough. At what point did you think this might be a
KURO-O: Actually, at that time, maybe there was no example for single-gene
mutation causing aging-like phenotype. That was one thing, I think. And another
thing is, actually, identification of the gene caused by insertional mutation
01:25:00was pretty tough at that time. So technically it was challenging. That may be
Maybe it's because a single gene may regulate aging. Recently it's not a very
new concept, but at that time I think it was pretty new. Of course, some people
argued against me because these mice developed many aging-like symptoms, but
they might simply be sick and develop many diseases, and it may have nothing to
do with aging. That's a very reasonable criticism, I think. Actually, I spent
01:26:00the next four years arguing against that.
MEJIA: How did the writing process go for writing all that up? Was that done
with other people, or was that you?
KURO-O: Yes. I wrote it down by myself, and yes, it's not very difficult. It was
a really straightforward study, just simply spend a lot of time, I spent a lot
of time, but it's very straightforward. I made the mutant, the mutant showed
this kind of phenotype, I identified the gene, and I rescued it with the
aging-like phenotype. That's pretty straightforward and simple, logical
sequence, so it was not difficult, and I also had it checked by the native
speaker. But essentially I wrote it by myself.
01:27:00Actually, after submission, Nature editorial office extensively revised my
writing. Actually, the original article I submitted was a series of three papers
for phenotyping. The first article just described the aging phenotype, the
second paper identified of the gene, and the third paper, rescued the mutant
phenotype. But Nature wanted us to combine everything into one single big paper.
So when I submitted it the first time, there were a total of twenty-seven
figures and tables, but Nature asked us to compress it to six figures and
tables. Somehow we did that, and Nature liked the new style, so it took not a
01:28:00very long time to be accepted.
I was actually very worried about whether they could accept the concept that
this was a model of aging. That was a point, I thought. But fortunately, the
reviewers agreed with my opinion. In technical part, I think there was no room
for discussion. It was very straightforward. But the interpretation of the
results regarding these mice as an aging model could be a little bit
challenging. Fortunately, the editors and reviewers accepted that interpretation.
MEJIA: Forgive me if I'm wrong, because I'm not very technical, but in reading
up on your work before this, one point struck me as interesting because it looks
like your mutant produced symptoms more similar to human aging than to mouse aging.
01:29:00KURO-O: Right. Exactly right. So even if you keep the mice for a long time, they
never develop phenotypes like Klotho mutant. Phenotypes that develop Klotho
mutant mice are very similar to human aging-like phenotypes, like
arteriosclerosis, osteoporosis, emphysema, skin atrophy, and many other features
of human aging. So, right, it's not the acceleration of natural aging process of
the mouse, but it's some mechanism that might be related to human aging or
human-aging-related disorders. That's another very important point, I think. So
01:30:00it shouldn't be regarded as acceleration of mouse aging; it should be regarded
as a model of human aging.
MEJIA: Then this fairly big paper comes out in Nature. Can you describe what
that was like for you in your career?
KURO-O: Oh yes. It totally changed my life. So I didn't expect that publication
in Nature could cause such a big impact in every aspect of my career. Yes. I
just wanted to publish these findings, maybe Nature would accept it. That's the
only reason why I submitted my paper to Nature. Any paper would be fine. Science
would be also a great journal, or even they might reject us, but I was pretty
01:31:00happy if I could put my data in any journal. That was what I thought at the
time. Actually, I was surprised that the institute planned the press conference.
I never expected that, but they indeed did a press conference, and it was good
advertisement for the institute and also a good advertisement for the grant
program that supported me at that time, but it was a really interesting
experience for me.
01:32:00From a scientific point of view, this paper was a really interesting paper, but
identification of the gene was not, of course, good enough to understand the
aging mechanism. I thought it would be very important after I found the gene. To
identify the gene is one thing, but to identify its function is another thing.
What I had to do next was to identify the gene function, or function of this
gene, or function of this gene product, Klotho protein, but I had no clue how to
01:33:00address that question at the time. I was pretty happy when I got published, my
paper, in Nature, but at the same time, I felt a little bit of anxiety because I
had no clue to the next step at that time. But the impact was really high. Many
people wanted to study the Klotho gene, but there was no clue how to analyze
Klotho function at that time. So, yes, that's what I felt at that time.
MEJIA: And you had developed the mice, so I guess you would have been the source
for everybody's inquiries? People would have come to you if they had questions
about how to try and study this?
KURO-O: Yes. Right. Other people wanted to use these mice for their own
01:34:00research, that's right. Many people working on, say, aging. So one might want to
see what changes would be observed in the central nervous systems of people who
are working on Alzheimer's, of course, are interested in this aging model.
Of course, every organ has some phenotype, so, yes, that's one we actually saw,
the phenotype in each disease, observing Klotho more precisely, more deeply, and
understanding why this happens or to find out the mechanism.
That was one way to go, actually, but I didn't want to go that way, because I
01:35:00would rather leave those projects to them. But rather, I'd like to focus on what
is the fundamental function of the Klotho protein. That was really the
challenging part, that maybe I should work on that.
MEJIA: We're going to break and continue tomorrow.
[END OF TAPE 1, SIDE 2]
[END OF INTERVIEW]
MEJIA: This is Robin Mejia here with Makoto Kuro-o on March 7th, 2006, in his
office at U.T. [University of Texas] Southwestern [Medical Center] for the
second day of the Pew [Scholars Program in the Biomedical Sciences] oral history interview.
So when we left off yesterday, you had just published the results of your
five-year intense work in Japan, and that was about to lead into many big
01:36:00things. But when I was reviewing the tapes, I just had a couple of questions
that I wanted to start out with before we jump back in there, which is, at point
during your schooling did you learn English?
KURO-O: All Japanese students learn English at the junior high school, so age
twelve, thirteen. In high school, students usually take English courses, and
some students take French classes or German class, but maybe 99 percent of the
students take English classes in high school, too. So a total of six years,
three years junior-high-school education, three years high-school education, so
a total of six years of English classes.
01:37:00But the problem is, teachers are all Japanese. So, yes, I think probably
Japanese are probably very good at English education in Japan, very good in how
to read English, how to write English, but speaking and hearing is another
thing. So that's why most Japanese are not very good at speaking and hearing
English, but probably very good at grammar and spelling and writing or reading, maybe.
MEJIA: That makes a lot of sense. Those are two different things, and written
English isn't always phonetic, either.
Six years was enough so that when you were at a point where you wanted to
publish and needed to write, you'd be able to more or less do that fairly
01:38:00KURO-O: Yes. Of course, nobody uses English there, so if you learn English in
high school, usually you lose everything if you don't keep reading or writing
English. But in medical school, we sometimes use English textbooks, and of
course, after graduation we need to read English papers, so we have a chance to
continue to be exposed to English, reading especially. So that helped me a lot
to write up my own article.
But, you know, all English I read in medical journals, so I didn't know anything
about conversation or how to, say, order in McDonald's [restaurant], check into
01:39:00a hotel, or something like that. We didn't know nothing about that, but knew how
to write up scientific papers. I think many Japanese scientists and medical
doctors can somehow write or read English journals, but of course, they are not
MEJIA: Right. Well, I imagine staff at major journals are probably used to
working with people on their English when they need to.
KURO-O: Yes. Actually, Nature editorial office helped me a lot, maybe almost
each sentence, sentence by sentence, and, yes, it's actually very different from
my original writing. But that made the article much shorter and more
01:40:00comprehensible, understandable, readable, easy to read for many people. So
MEJIA: And this brought up another question I was thinking about. During your
medical training, initially you said you were very focused on the clinical side,
and that was your intent, was to be a clinician and doctor. How much were you
tracking journals and research during that point? Did you have time for that?
KURO-O: Yes. After graduating medical school, during the internship, I didn't
have any time to track basic research journals, but when I came back to Tokyo
01:41:00University, I started some basic research, so naturally I needed to read some
related topics. At that time there was no PubMed or there was no good database
for journals, so we just read the special journals. At that time I read, of
course, Nature, Science, something like that, but I was interested in
cardiology, so I read some journals like Circulation Research and Circulation or
some specific journals. I had some time to read such papers, but maybe it was a
little bit biased. We didn't have any good database such as PubMed at that time,
01:42:00but yes, something like that.
MEJIA: Two more here before we come back up to time. You talked about visiting
Dr. [Ryozo] Nagai in Vermont, but how did you meet him originally? Did you know
him from your time here?
KURO-O: Yes. I told you that I spent some time in a research lab when I was a
medical student, summer vacation for a couple of months, and he was in Japan at
that time. He left Japan just maybe a couple of months later, but at the time he
was still there, I had a chance to meet him. But at that time, of course, I just
01:43:00met him. But he went to the University of Vermont, and actually, the boss Yoshio
Yazaki of the laboratory gave me a chance to go to the University of Vermont
because Dr. Nagai was there, and I spent two months there at the University of
Vermont. So that was the first time for me to closely interact with him. So this
boss actually had me come to meet Dr. Nagai.
MEJIA: He may have talked with his boss and said, "I know this doctor from Japan
who's really smart," and, "Can we bring him over for a couple of months?"
01:44:00KURO-O: Probably boss said, "I have a student that wants to visit the United
States," something like that. So, yes.
MEJIA: And so that's when you two got to know each other, which led to him
pulling you back towards research here?
KURO-O: Yes. Right.
MEJIA: And then moving up closer to where we were yesterday, I was struck by
this when I was looking at your papers beforehand and again when I was listening
to the tapes. It does sound like you really took off on a pretty novel path
after you got your Ph.D., when you decided to figure out which gene had been
knocked out in your mutant. Was that a big decision? Was that just self-evident?
What convinced you that you could go do this thing that nobody else was doing?
01:45:00KURO-O: Right. To tell the truth, at that time I didn't feel that I made a big
decision, because I mixed mice and found a very interesting phenotype, so
naturally I just wanted to know what was going on in that mouse. To do that, I
had to give up clinical duties. So that was a very natural way to go. But after
several years later, when I thought about my career, I realized that that was
really a big decision. At the time I didn't realize that that would be a big
decision, because I just wanted to know what was going on in that particular
01:46:00mouse. But that required me to change my career. So that's why I did that.
MEJIA: You described fairly eloquently yesterday what you did to find that gene
and determine that it was responsible for what you saw. You also mentioned you
were working pretty independently at the National Institute [of Neuroscience of
Japan] at that point. How did you go about finding the tools and techniques and
figuring out what to do next? Was that from just talking to other researchers
there or from literature? How did you determine your course of action?
KURO-O: I explained in the design or something like that?
MEJIA: Yes. How did you design the experiment that sounds so clear and obvious
when you explain it after the fact?
KURO-O: Right. I had a background in molecular biology, so cloning of the gene
01:47:00was technically not very challenging for me, but of course the sequence I needed
to look at was fairly big, so I thought it would be very laborious work, but
basically all the techniques necessary for the identification of the gene, I
just used the conventional molecular biological technique that I learned from
Dr. Nagai. So technically it was not very challenging, but the amount of the
sequence we needed to analyze was pretty big, so that took me a lot of time and
01:48:00paper. So, yes, you can get some genomic fragments. It's not so very difficult
to get the genomic fragments surrounding the insertion site, but we needed to
know its portion includes the actual protein, the exon. So identification of the
exon in this region took almost two years, maybe, for me to identify the
potential sequence. I used the technique learned from Dr. Nagai, and the methods
01:49:00I just got from literature, old literature.
The good thing is that in the Department of Molecular Biology had several
faculty members, and one of them, two of them, worked on flies, fly genetics.
They were routinely doing that kind of work. In fly genetics, they pick up some
interesting mutant and identified which gene was disrupted in that fly. So it
was completely the same thing in fly. But in mice, the genome size is much
bigger, so the analysis is a little bit more complicated. But theoretically, the
01:50:00principle of the experiment was almost the same. So I sometimes got some advice
from such fly guys. That was very helpful. That was very lucky for me, too. The
fly geneticists [Drs. Fumio Matsuzaki, and Chihiro llama] were next door from
me, so that was very lucky.
MEJIA: Okay. That makes sense. So then moving forward to where we were
yesterday, which is you'd gotten the results and the paper came out, and just
before we wrapped up, you were just starting to explain the reaction of the
scientific community, what happened next in your career.
KURO-O: Right. Well, at that time there was no mammalian model for aging, so
01:51:00probably the Klotho mutant mouse was the first example of human aging in
general. Actually, there were a couple of aging model mice at the time. It's
called the senescence-accelerated mouse, SAM, SAM mouse, but they are a natural
mutant, and the inheritance of the aging phenotypes are very, very complicated,
probably because, they are not caused by single gene mutations. So nobody knows
what genes are mutated in that particular mouse, or more importantly, there are
01:52:00several substrains in SAM mice, and each substrain expressed some other
aging-like phenotype. So any single substrain expressed multiple aging-like
phenotypes. The unknown characteristic feature of aging is that a single
individual gets multiple diseases. That's a very characteristic feature in aging.
But these mutant mice did not have such multiple phenotypes in the same
individual. In that sense, the Klotho mutant mouse was the first example of
01:53:00aging. But the impact was, I think, really big, but at the same time, nobody
knows what the gene is doing, I mean what the Klotho protein is doing. Nobody
knew at that time. So everybody thought that was a very interesting finding, but
there was no clue to the next step at that time.
So after publishing the Klotho gene paper in Nature, there was no major
publication probably for more than several years. I provided Klotho mutant mice
to many researchers, and they were interested in particular phenotypes. I gave
01:54:00it to an ophthalmologist and he looked at whether they had cataracts or not. I
gave the mouse to, say, a cardiologist, and he look at how the arteriosclerosis
was going on, something like that. But it was a kind of descriptive study and
not getting too deeply into the mechanism of the disease or Klotho protein
function. So, yes, it was good I could publish the paper, but the next step was
pretty much invisible at that time.
MEJIA: Scientifically the next step was invisible, but maybe could you talk a
little bit about what happened next in your career? Were you invited to talk on
01:55:00this to people? Did you become more of a name suddenly?
KURO-O: I got invitations from many institutes at that time. At that time I was
a postdoc [postdoctoral fellow], so naturally, I wanted to get to be assistant
professor or want to have my own lab, independent laboratory. But, I didn't
know, in Japan, everybody has got to get totally independent before age, say,
forty. Actually, I said I belonged to the molecular biology department in the
01:56:00National Institute of Neuroscience, and the chairman of that department was Dr.
Nabeshima, Yoichi Nabeshima. He's a Ph.D. and he is a basic scientist, and he
worked on muscle development for a long time, but he was also very interested in
01:57:00Klotho mouse. He actually got very famous because of the Klotho mutant mouse.
After publishing the Nature paper, he planned to move to Osaka University, and
he offered me a position under his control. I couldn't be independent if I
accepted his offer. So I wanted to be independent and I wanted to have my own
laboratory, but it might be too early for me in Japanese society. So I almost
01:58:00accepted his offer, but when I came to U.T. Southwest and I met Dr. [Errol
Clive] Friedberg, the chairman of this department, he offered me a very good
independent position and laboratory space and start-up funds.
But I never thought about coming to the United States, and I was looking for a
position in Japan, so I never thought about coming here, coming to the States.
So I couldn't decide immediately. I need to talk with my wife [Kumiko Kuro-o],
of course. But eventually I decided to come here. The main reason was because I
01:59:00would be able to have my own independent laboratory, and, second, as long as I
continued Klotho research in Japan, Dr. Nabeshima would be very influential, and
all the work I would do in Japan might be not very fairly evaluated. You know
what I mean?
In Japan there is a kind of hierarchy, so everybody knows that. The boss never
does the actual experiments, but the assistant professor or postdoc people,
whatever, are doing the actual research. But all the publications would be
02:00:00usually corresponding also to that big boss. So in Japan everybody knows the
system, everybody knows, okay, the corresponding author is the famous guy, but
probably this work was done by the last one or something like that. So in Japan,
everybody knows. But if you publish it, if the scientists in Europe or the
United States read the paper, 100 percent of the people believe that this work
was done by the big boss. So there's a discrepancy between the publication
style, and who the actual work was done by.
02:01:00If I stayed in Japan and worked with Dr. Nabeshima and published many papers, if
I did that, still people would believe that this work was done by Dr.
Nabeshima's laboratory; that was not actually very fair for me. So I really
wanted to get independent from him.
Of course, if I could find a good position in Japan, that would be one choice,
but maybe moving to the United States would make the things more clear. If I
could publish a good paper from my own laboratory in the United States, the
things are very clear that this work was done by myself and not by Dr.
Nabeshima, something like that. That is one thing.
02:02:00But of course, another reason is I really wanted to see what was going on in the
United States in the basic science area. I never had a chance to visit United
States. Of course, I did visit the University of Vermont, but it was just when I
was in medical school, and it was just two months. It was not enough to see
everything. So I really wanted to look at how basic research was going on in the
United States. So, yes, those are the two major reasons why I moved to the U.T. Southwestern.
MEJIA: That makes sense. It sounded like you said you weren't actively looking
in the U.S. [United States], even though you had ended up with the offer. How
did you end up coming here for a seminar? I think you said you went to another
02:03:00KURO-O: Yes. In 1997, I remember it was November. There was American Heart
Association meeting, and I applied for Young Investigator's Award for the
meeting. It was in Florida, and I went there. But at that time the Nature paper
was not published yet. The paper was published November 7th. But Dr. Yanagisawa
02:04:00was in this campus, knew that I was working on Klotho mice, and isolated the
Klotho gene, and that the paper was accepted to Nature, so he invited me to
I just went to the joint aging meeting and just stopped by Dallas, [Texas] and
gave a seminar and Dr. [Errol Clive] Friedberg was talking about offering me a
position. But I couldn't decide, so I went back to Japan and thought about four
months or so whether I should accept this or whether I should still search for a
position in Japan. Actually, in Japan there were several professor positions
02:05:00available for me, but I knew that several candidates had applied for a single
position, so there was no guarantee that I could get the position. In Japan, the
professor is selected by voting by the other professors, so there is a little
bit of a political thing. I don't know whether I could be a professor in Japan.
But Dr. Friedberg's offer was just yes or no. If I accepted, I could have the laboratory.
MEJIA: So he made the offer during your trip?
02:06:00KURO-O: Right. I was really surprised. I didn't know him at all. I first met him
and I just talked with him and showed my data, and just talked with him ten
minutes or so, but he offered me the position at the spot. I was really
surprised. I don't know how he did that. Maybe my work was a little bit related
to his research, because he is working on DNA repair systems, and that is
actually directly related to aging. So maybe that's why he was very interested
in my research.
Fortunately, at that time he got an endowed scholar program offer [Southwestern
02:07:00Medical Foundation Scholar in Biomedical Research]; the Department of Pathology
can take one junior faculty using that particular endowment. So he was actively
looking for a junior faculty at that time. But that was really good timing for
me. That fit his research interest and his project, and, yes, everything fit fine.
MEJIA: That was probably the first year of that program, right?
KURO-O: Right. I didn't know at all about the program, but Dr. Friedberg said to
me that I would offer $600,000 for start-up funds. So it's a lot of money. In
addition, of course, I could get independent laboratory space. Yes, it's a
02:08:00really good offer, but it's in the United States, so it was a big move for me. I
was thirty-eight at that time. Brain is getting more stiff. It's getting harder
and harder to learn new things and especially new languages. So that was a
really big factor for me when I decided to come here.
I didn't know how the students are educated, what education was going on in the
02:09:00States. I had no idea about how the granting system works in the United States.
It's totally different. But anyway, his offer was really good, so I could not resist.
MEJIA: And how did your wife [Kumiko Kuro-o] react?
KURO-O: Well, at first she really didn't like to move to the United States. She
is thirty-seven, one year younger than me, but still thirty-seven.
Unfortunately, she took French when she was in high school. One percent, very
rare case. She learned French literature in the university, so she had no
02:10:00English at that time, so naturally she didn't want to be here. But anyway, to
improve my career, there was no choice but to be here, so I persuaded her and
she eventually said okay.
Of course, she had a very difficult time for the first several months, and she
had no English and no friends. Actually, she never drove in Japan, so here in
02:11:00Dallas without a car, she cannot go anywhere. But there were several Japanese
families in U.T. Southwestern, and actually there were some Japanese postdocs in
Dr. Yanagisawa's lab and Drs. Brown and Goldstein's lab that helped us a lot.
Actually, we knew their family when I was in Japan because we worked for the
same department in the University of Tokyo, and actually, my family and his
family lived on the same condominium in Japan for several months, so we knew
each other very well. So their family helped us a lot. His name was Dr. Shimano,
02:12:00and his wife helped my wife a lot, taking her everywhere, where to buy the food
or where to buy the housewares, Target and so on. But that really helped me,
actually. So she was gradually getting used to the American style of life.
She also went to community college to learn English as a second language, ESL
[English as a second language]. She took ESL classes in the local community
college, and yes, she did pretty well, and she graduated two years ago. It was
02:13:00really good for her, and she got some friends there, and she, of course, learned
English. Now maybe she is enjoying the life much better than me, maybe. Yes.
Women are very strong.
MEJIA: That does sound like a fairly big move.
KURO-O: Yes, indeed.
MEJIA: What did your parents [Masahiko Kuro-o, Nobuko Kuro-o] think?
KURO-O: Well, actually, many M.D.'s in Tokyo University spend several years,
maybe three, four years in the laboratory of the United States to learn the
02:14:00experiments, to look at what is going on in the United States. So my parents
thought that I was just spending several years, a couple of years, and we'll be
back soon. So that's okay, something like that. "It's a good experience for
you." But it's already eight years, almost eight years, since I left Japan. So,
yes, my parents, they probably think that as long as I am successful here, they
will be okay, because eventually children need to get independent from their
parents. But they are getting very old, and I'm a little bit worried about it.
02:15:00Actually, my father [Masahiko Kuro-o] had a stroke two years ago, and his left
side is a little bit paralyzed, but my sister [Atsuko Rakuman] lives very close
to the parents so she can take care of them. That's good for me. Every time I
have a chance to get back to Japan to give a seminar, I always stop by my
parents' and see how they are doing. But maybe this year I will have a chance to
get back to Japan three times. That's good for me. So, yes, that's my only
concern in Japan, but otherwise, we think they will be fine as long as I'm happy here.
02:16:00MEJIA: Okay. I'm going to flip this over here.
[END OF TAPE 2, SIDE 1]
MEJIA: Okay. We're on side two of the second tape.
So could you maybe now talk a little bit about the experience of coming and
setting up the lab? So you have this, from what I've read about the
[Southwestern Medical Foundation Scholar in Biomedical Research] Endowed
Scholars Program, probably a pretty great offer.
KURO-O: Yes, yes. It was a very good offer, and it provided me $300,000 for the
first year and $100,000 for the second, third, and fourth years. So in total
MEJIA: Is that in addition to a salary?
KURO-O: Right. Salary was taken care of by the department. It's a direct cost,
02:17:00so I can use it for research. Well, but I didn't know at all about the system,
so actually I hired too many people at first. I hired three postdocs
[postdoctoral fellows] from Japan [Hiroaki Masuda, Tasuo Suga, Hirotaka
Chikuda], and at that time I had no idea about how much money they spent,
including their salary. So three postdocs are a little bit too much for my
budget. And I also had a big mouse colony, and that costs a lot to maintain the
02:18:00mouse colony. So actually, the budget was not enough for me. But fortunately, I
could get several small grants. Of course, Pew [Scholars Program in the
Biomedical Sciences] provided me from 1999; it was the next year after I arrived
here. At that time the budget was really tight, so I was really very happy I
could get the support from Pew [Scholars Program in the Biomedical Sciences].
That money really helped my laboratory. The budget itself is not very big, but
still, for my small laboratory, that was really a big amount of money.
And I got some very pilot program type of small grants from NIH [National
Institutes of Health], yes, something like that. President's Research Council
02:19:00Award [President's Research Council Distinguished Young Researcher Award at U.T.
Southwestern]. It was actually good money for me, but it was only a one-time
fund, grant. So I really needed to get an NIH [National Institutes of Health]
R01, but it was really tough to get the brand-new R01.
But anyway, when I started the laboratory, the budget was very tight, and I got
postdocs from Japan. So actually, nobody knew about the system, right? So I
didn't know very well about the system in the States, and the postdocs from
Japan, of course, didn't know anything about what was going on in the States.
But I got one technician [Rosa Shamlau], and of course, she is from the States,
02:20:00and she helped me a lot to set up the laboratory. Of course, the department
supported me a lot. I worked with a secretary [Lisa Jones] who was very
experienced. I just asked her, "I want this and this and this and this," and
then she placed an order and arranged the shipment and everything. So anyway,
maybe it took a couple of months to get everything, all the equipment I need in
the laboratory, and then started the research somehow.
02:21:00But at the time I had no clue to the Klotho protein function, so I built some
hypotheses about the Klotho protein function and we tested that, but every time
we tested it, the hypothesis was not working. So there was no data that I could
publish. For maybe the first four or five years, I had no good data that could
be published in a good journal.
But I continued some collaboration with my friends in Japan, researchers in
02:22:00Japan, and we could somehow get some publications, but I couldn't get a good
publication about the data generated in my own laboratory. That was a really
tough period for three, four years. And every time I submitted a grant to NIH,
it was rejected or got a low score. So that was a very tough year, anyway.
MEJIA: How did you learn to navigate the grant system? Did you work with anyone
here to learn how to write NIH grants?
KURO-O: Yes. Actually, the chairman, Dr. Friedberg, helped me a lot. Of course,
he got a lot of grants. He just showed me how to write up the grants, an actual
02:23:00example. He gave an actual example how the grant should be written up. And after
I thought up the grant, he checked my English and the organization of the
writing. So he really helped me a lot. Yes, anyway, I just borrowed a grant that
was approved, from several colleagues, and just looked at it and thought maybe I
should write it up in this way or something like that.
The good thing in the States is they let me know what was wrong and what was a
weakness of this proposal, what was the strength of this proposal. Actually, in
02:24:00Japan there is no such feedback. I just applied for the grant, and I just heared
yes or no; there was no feedback about what was wrong. So I thought the grant
was something like that. I thought it was different from publishing a paper in
the journal and there was no feedback at all. But I could get some feedback from
NIH so I gradually understood what was wrong in my proposal and what they required.
I could submit, of course, a revised grant, and the score got up a little bit,
02:25:00but still didn't reach to the funding score. Lots of failures taught me how to
write up the grant that could be approved by NIH. So maybe I tried five times
and failed five times, and the sixth time the grant was approved. It was 2002,
and that was a really critical time for me, because the Endowed Scholars Program
ended on that day, on that year. So if I couldn't get any funding by 2002, I had
02:26:00to close my laboratory. There was no overlap at all. I was cleared. But anyway,
somehow the project continued that critical period.
MEJIA: So it sounds like the Endowed Scholars Program was actually key for you
in doing what it says it would do, which is give people the time to pursue
something novel and different.
KURO-O: Right. Indeed. Yes, it's a totally new gene and totally new protein. Of
course, nobody knows what this protein is doing. Yes, a good example is APP,
Alzheimer amyloid precursor protein. Actually, that protein encodes a membrane
02:27:00protein. The APP protein is actually accumulated in the Alzheimer patient's
brain. Everybody knew that a long time ago. APP was isolated a long time ago,
but nobody knows what this APP is doing. Literally thousands of researchers in
the neuroscience field want to know what this APP is doing, but still its true
function is not very clear. So the same thing could happen to Klotho. It's also
a membrane protein, and the only data available is when you disrupt the Klotho
gene, mice look like aging. That's all we know. So, yes, thousands of
02:28:00researchers worked on APP, but still its function is not known.
In the case of Klotho, I'm the only person working with the Klotho protein, and
it's very likely that I couldn't understand anything about the Klotho protein.
That was actually the big fear for me, anxiety for me, or concern for me during
the first four years. It might be too tough for me to pursue. Indeed, we didn't
get any excellent data in the first four years. And budget time was very close,
getting very close. So, yes, that was very tough for me.
MEJIA: This is your first principal investigator [position], assistant
02:29:00professor, as you said, you were running your own lab. How did you work with
your postdocs? How were research ideas generated? Were they bringing in their
own ideas? Were you still directing the ship? Were they bringing stuff in?
KURO-O: The postdocs I hired from Japan were all cardiologists, actually, so
they just wanted to spend a couple of years. Of course, if they could do good
work and publish a good paper, that would be very nice, but one of the major
02:30:00purposes for them was to learn the American system of science. In that sense,
they are not 100 percent committed to the science. That's known. Actually, for
them it was a very special period of time. They were very busy once they got
back to Japan, taking care of patients and doing many critical duties, but they
were allowed to spend two years. Usually two years is the maximum for them. So
two years to look at the United States and to be exposed to basic research, so
they had a little experience with basic research.
So for such people, I think two years is too short to contribute to science in
depth, because for the first several months they needed to spend more time
02:31:00setting up their life in the States and taking care of their families in the
different environment. So they spent several months for that, and they spent
several months learning how to use the pipette, how to use the machines. After
that, they could start research. But they had to get back to Japan two years
later. So the actual period they could really focus on science was probably only
one year or so. That was too short for them to generate productive data or to
propose a good hypothesis. Actually, that was probably one of the causes that we
couldn't get good data for the first several years. They are really clever and
02:32:00they have a big ability. If they could spend another year, three years or four
years, but two years was too short for them.
Japanese medical doctors spend two years usually in a big lab, established lab.
So in those laboratories there are lots of projects going on and there are
already established methods or assays, and they just work on one part of the
team. Two years might be okay if they work for the very big established
02:33:00laboratory. But in my laboratory, it was not very established. I didn't know
what way to go, still searching for which way to go. So in such a small
laboratory they might not be very happy, I think, because they couldn't get a
good publication during the stay. So it was really a frustrating period for both
of us because they couldn't get good data, I couldn't provide a good project.
But I couldn't do anything other than that, so I had no choice. Anyway, I had to
struggle, pursue any possibility or any hypothesis that might be promising. But
as you know, science is not always easy.
02:34:00So, yes, maybe it was in the third year, maybe, 2001 or 2002, we noticed that
the Klotho protein might be involved in the insulin pathway. That was the
breakthrough for me. At that time, all the postdocs went back to Japan, and I
was totally alone. Actually, I hired one postdoc, but for a few months I was
totally alone. Nobody was in that laboratory because there was no budget to hire
02:35:00people. So the postdocs had gone back to Japan, so a certain period of time I
was totally alone. I had no technician, no postdocs.
At the time I noticed that Klotho might be involved in the insulin pathway. So
what I did was, I made the recombinant Klotho protein in insect cells; I just
injected the Klotho protein and measure blood glucose levels, and indeed, Klotho
protein can affect insulin. So that was the first breakthrough of the Klotho
MEJIA: I want to pursue the scientific breakthrough. I'm just curious at this
point, why did you hire all Japanese postdocs?
02:36:00KURO-O: Well, right. I wanted to hire, of course, good postdocs, but as you
know, good postdocs want to go to a better laboratory. It's natural, because if
I were the postdoc, I would never go to a laboratory like my laboratory. It's
really small, and still struggling to establish my position. Anyway, the
direction wasn't clear at that time. So, yes, there were lots of potentials in
those mice, but still, until I can show some directions, maybe no postdocs would
02:37:00like to work with me, and I also didn't want to hire postdocs until I could show
a clear direction to them. I really wanted to get a good person, but nobody
would join my laboratory at that time. It was really tough.
MEJIA: So it sounds like through this whole period, then, you were basically the
intellectual driver, you were the person coming up with hypotheses.
KURO-O: Yes. Right. Right. And in addition to the experiment, I had to maintain
02:38:00my mouse colonies and make Klotho protein, basic daily routines, and paperwork,
still maintain the laboratory and everything. I had to do it by myself. I
couldn't spend 100 percent of my time on the experiments, so that was also a
stress for me. Still, I think it was okay anyway. Somehow I survived.
MEJIA: Do you have any teaching responsibilities here?
KURO-O: Yes, but the teaching duties were very small, and I just had a class for
aging, elective courses and just give a lecture once a year. That's all. That
was good for me.
02:39:00MEJIA: What year was it when you were alone in the lab and started to notice the
insulin response? Was that 2001?
KURO-O: It was maybe around 2001. Yes.
MEJIA: So that was right around when you got your first yes from the NIH, too. Right?
KURO-O: Right. Based on that very preliminary data, I could show some direction
of the Klotho protein function. That helped me to get NIH R01. So that was
02:40:00really a big breakthrough. Yes, actually, the program director in the NIH was
very interested in the Klotho project. When my application got a good score, the
program director immediately called me and said congratulations to me. He said
that he was very interested in this Klotho project and he really wanted me to
get funding. So, yes, he was also pleased to know that I got a good score.
02:41:00But anyway, from 2002 I got $250,000 every year, so that helped me a lot, of
course, and I could get postdocs, technicians, and I could pursue the Klotho
protein function on the insulin signaling pathway.
MEJIA: How does your salary work here after the grant runs out? Do you fund yourself?
KURO-O: Yes. Right. Before I got the NIH funding, the department 100 percent
paid for my salary. But after I got NIH grant, I replaced a little bit, part of
02:42:00my salary, maybe 20 percent or something. Actually, I got another R01 two years
ago, so then another 20 percent or something like that. So currently I think I
pay 40 percent of my salary and 50 percent from the state. So 10 percent from
the department, something like that, I think.
MEJIA: I'm curious because that varies a lot depending on the type of
institution, it seems like. I'm sorry, I didn't mean to sidetrack you too much
from the science, because it was getting pretty interesting. So you got the
preliminary results in that period on your own. You got money. Could you maybe
describe the next step? Were did you find your postdoc or technician? How did
02:43:00you go towards gearing up now that you had more of a direction for your proposal?
KURO-O: I found that the Klotho is involved in the insulin pathway, maybe 2002
or somewhere in that. Actually what I first started when I came here was to set
up the mouse colony for a lifespan monitoring of the Klotho mutant mice. So you
might remember that when I published the Nature paper, one of the biggest
criticisms was whether the Klotho mutant mice are indeed aging or not. Klotho
02:44:00mutant mice indeed look like aging, but they might just be sick and they just
simply develop many diseases, so Klotho mutant mice might not be aging. The
Klotho gene might not be involved in the natural aging process. That was major
criticism. I think that was very reasonable criticism.
So to argue against that, I needed to prove the opposite. If you overexpress
Klotho, then the animal would live longer than wild-type mice. If we can show
that, that would be the definite proof that Klotho is indeed involved in the
aging process, because lifespan extension cannot be explained without assuming
02:45:00that the aging process was inhibited. Lifespan can be shortened by any reason.
If the animals are sick, they will die early. It's not necessarily because of
aging, but because of diseases.
But the opposite never happens because of disease. The lifespan cannot be
extended by diseases. So if the lifespan is extended, then that would directly
mean that the aging process has been suppressed. But, as you know, it takes
time. Laboratory mice live usually two years on average. So to prove that Klotho
overexpressing transgenic mice live longer than wild-type mice, probably you
have to wait three years, four years.
02:46:00So the first thing I did was to set up the mouse colony for lifespan study. I
had transgenic mice that overexpressed Klotho, so I just set up several mice,
just kept them, and observed how long they lived. The lifespan data, I finished
the lifespan study around 2002. I came here in '98 and set up the lifespan study
and waited three or four years. So the lifespan study finished around 2002. It
turned out that Klotho overexpression indeed extended the lifespan of the mouse.
02:47:00That was another breakthrough. So two breakthroughs came along at the same time.
MEJIA: So you set that one up to run in the background?
MEJIA: To run in the background, that just means to let that one run while you
pursued the other.
KURO-O: Right. Right. Sure.
MEJIA: So you created another mouse that overexpressed Klotho?
KURO-O: Right. Actually, I made it in Japan to rescue the Klotho mutant mice. I
brought those mice here. So in 2002, I knew that the Klotho is involved in
insulin pathway and Klotho overexpression extends lifespan of the mouse.
02:48:00At that time, studies on lifespan were done usually by using worms and flies, C.
[Caenorhabditis] elegans and Drosophila, because their lifespans are short, so
it's easy to monitor their lifespans. Of course, the genetics are very excellent
in those model animals. So from the studies on worms and flies, it had become
evident that inhibition of insulin signaling pathway can expand the lifespan of
worms and flies. That was the emerging concept at that time, and actually that
fit in with the Klotho protein function very well, because Klotho can inhibit
02:49:00the insulin pathway and Klotho expression extended lifespan. So the same story
might be true in mice. That makes a lot of sense, so probably that's why NIH
funded me, that that project might be promising.
So what was the original question? I am sorry.
MEJIA: The original question was about hiring postdocs, but this is good if we
can stick with this for a minute.
KURO-O: I'm sorry.
MEJIA: No, this is great. This is really interesting. So okay, I was just
checking, it was in 2002.
KURO-O: Okay. So about the postdoc.
MEJIA: Just to make sure I understand, it sounds like--and I do want to come
back to finding the postdoc--the model of insulin resistance extending life
02:50:00existed only in the simpler systems. At that point nobody knew for sure. So that
was once again a hypothesis.
MEJIA: It seems logical, but it was a hypothesis that the two were connected.
KURO-O: Right. Exactly right.
MEJIA: Okay. Well, maybe it is a good time, then. So you have good data, you
have money, you can take a deep breath. What do you do next?
KURO-O: Although I was funded from NIH, but I needed to really get a good
publication. Actually, there was no big publication at that time for me. I found
that Klotho was involved in the insulin pathway. I found that Klotho extends
02:51:00lifespan. So actually, I wrote a paper using that data. That paper describes
about Klotho overexpression extending lifespan in mice. That fact alone is very
interesting, I think. But in addition to that, I showed that Klotho is involved
in the insulin signaling pathway, and I combined this data and submitted the
02:52:00paper to Nature first, but Nature rejected that paper. It was not clear what was
wrong in the review process, but anyway, they didn't like my paper.
Klotho can inhibit the insulin pathway. Klotho expression causes insulin
resistance, so usually insulin resistance is directly related to diabetes.
Usually diabetes won't extend the lifespan. That's bad for health. So that was a
major question. But I think it depends on how strong the insulin signaling
02:53:00pathway is. What genetics in lower animals tells us is moderate inhibition of
the insulin signaling pathway extends lifespan, but if you inhibit it too much,
of course they are not happy, and of course in mammals they develop diabetes. So
that's not good. But it depends on how strongly they inhibit the insulin
signaling pathway. But such discussion cannot be acceptable for reviewers, and
anyway, that paper was rejected.
The next question is, what is the mechanism by which Klotho inhibits the insulin
02:54:00pathway? Because Klotho is a membrane protein, and actually it's expressed only
in the kidney and brain, if you disrupt the Klotho gene, all organ systems have
some changes, aging-like changes. So how do we explain this? Because its
membrane protein and expressed only in the kidney and brain, so how can these
proteins can affect, say, lung, muscle, liver? So our hypothesis was, the Klotho
protein is shed and secreted into the blood and saturated in the blood and
02:55:00targeted on the, say, lung, muscle. That was our hypothesis. So maybe the reason
why Nature didn't like my initial paper was because there was no explanation
about the mechanism by which Klotho inhibits the insulin pathway or extends
lifespan. So that's why we tried to purify the Klotho protein, soluble Klotho
protein, or make the equivalent protein in the recombinant protein, and purify
02:56:00it and look at whether this protein is indeed active or not. We thought about
that hypothesis several years ago.
So I tried to make recombinant Klotho protein, but the Klotho protein is a
really difficult protein, and I couldn't get enough amount of recombinant Klotho
protein. I tried many different methods, but no method worked very well. That
was another, actually, breakthrough. So it was a really difficult protein to
02:57:00make, but somehow I was successful in purifying the Klotho protein. We could do
some experiments using that protein, like injecting that protein directly into
the mouse or appling the protein on the cell or something like that, and we
could somehow show that this soluble form of Klotho protein is indeed active
protein and indeed circulates in the blood and could function as a hormone-like substance.
MEJIA: So this is work that came after Nature rejected the paper?
KURO-O: Well, we were working on that, but at that time the data was very
primitive primarily, so we just used the conditioned medium of the recombinant
protein. That's actually not very good data. We really needed to purify the
02:58:00protein. The method for purification was really tough, and we spent a lot of
time purifying the recombinant Klotho protein. But anyway, finally we could do
that and revised the paper. Maybe not revised it; it's a completely different
paper. We added the data about the recombinant Klotho protein and again applied
to Nature first. But Nature handled our paper as a revision of the previous one,
so they sent our paper to the same reviewer, and they again rejected the paper, actually.
Is that okay?
MEJIA: Can I change the tape real quick?
KURO-O: Sure. Sure.
[END OF TAPE 2, SIDE 2]
02:59:00MEJIA: This is March 7th, and this is Robin Mejia, still here with Makoto Kuro-o
in his office at U.T. [University of Texas] Southwestern [Medical Center], the
second tape of the March 7th Pew [Scholars Program in the Biomedical Sciences]
oral history interview.
So you were telling me about submitting to Nature, the first round of
rejections. Did you submit it anywhere else, or were you determined?
KURO-O: Well, no, I don't care about the journal, but I believe that that paper
was, I think, very interesting, because it was the first example, again, for the
lifespan extension in the mouse simply by overexpressing a single gene. It could
03:00:00be very interesting. Because I didn't have any good publication for four or five
years, I really need a good publication. Anyway, I wanted to publish in a very
good journal, and fortunately, I resubmitted the paper to Science, and they
Well, as I said, the concept that inhibition of the insulin pathway extends
lifespan was not very acceptable for all people, as I said.
MEJIA: Can I ask you, because it sounds from your description, is this the paper
that came out last summer?
03:01:00MEJIA: Okay. Because I did read that one. It's quite interesting. Which was 2005.
KURO-O: Five years.
MEJIA: So you spent another couple years, then, and you were publishing during
this time. I have your CV [curriculum vitae]. You were publishing a good bit.
KURO-O: Well, the paper before that was the result of collaboration. Of course,
we contributed the data, but those papers were done in both laboratories. My
laboratory contributed to that paper, but my collaborator also contributed a lot
to that paper. So it's the result of collaboration. But the Science paper was
03:02:00really originated from our data, and it's a purely made-in-my-laboratory type of
paper. So that was very important for me.
MEJIA: So you got your first results around 2003, 2002, then, from what you're
saying and just went back and kept refining?
KURO-O: Yes. Right.
MEJIA: I'm sorry if I cut you off when I changed tape. You were basically
explaining that you purified the protein. Did that help you better understand
the insulin reaction?
KURO-O: Yes. Right.
MEJIA: How did that tie back together?
KURO-O: To establish the concept that Klotho protein functions as a hormone-like
substance involved in the insulin signaling pathway, we really needed a purified
03:03:00protein because we needed to know whether this protein did bind to the cell
surface receptor. Any activity assay or any binding assay required the purified
Klotho protein. We actually made the Klotho protein in the insect cell system,
but purification was really tough. So that was a major drawback of the Klotho
research until 2004 or something like that. But once we got the purified
protein, we could do all necessary assays and experiments to prove that the
03:04:00protein indeed functions as a hormone-like substance. So that was not a huge but
a very necessary breakthrough for me.
MEJIA: Can we step back a little bit from the science? In a way, it sounds
almost like you were not setting up your lab again because you had your
equipment and space, but you had your set of Japanese postdocs [postdoctoral
fellows] and not so much work. They left. It was a period on your own. Who did
you bring in? How did you go about doing the science this next period?
KURO-O: There are many Japanese postdocs working in the U.T. Southwestern, and
03:05:00after I got funded from NIH [National Institutes of Health], I really wanted to
hire a very good postdoc. First, I looked inside of U.T. Southwestern for
somebody who might be looking for a postdoctoral position, and at that time, one
of the Japanese postdocs wanted to move their laboratory and he contacted
directly to me. He said he wanted to move anyway.
Actually, I have currently three postdocs. Actually, two of them are promoted to
instructor right now, but all of them used to work in other laboratories at U.T.
03:06:00Southwestern, and for various reasons they had to change laboratories. So they
were looking for a new laboratory to work for.
And actually I had an ad put in Nature or Science looking for an available
postdoc. I'm not stuck on Japanese guys, but it's just a coincidence that some
people wanted to move their laboratory for various reasons, for family reasons,
03:07:00or some people had a little complicated boss, or something like that. But they
are really experienced postdocs and they are all Ph.D.'s, so they are very much
determined to get their own papers published, and they really work very hard,
and I don't need to teach pipetting, how to pipette. Rather, they are much
better than me in carrying out various types of experiments.
So yes, I was lucky that I could get good, experienced postdocs by accident,
03:08:00actually. Actually, the two postdocs I got just after I got funded by NIH, so
they are very experienced and they had techniques that I didn't have. I'm very
good at mouse genetics and transgenic mice, something like that, because I
learned a lot about that, but those two postdocs [Hiroshi Kurosu, Masaya
Yamamoto] are very good at protein chemistry or signal transduction analysis
that I had never done before. So that was really the best match for me. I do
what I can do and they do what they can do, and they are really complementary to
03:09:00each other. After I got these two guys, the work progressed very well. Yes, that
was a major progress in my laboratory.
Recently, another postdoc [Yasushi Ogawa] joined my lab, and he's an M.D./Ph.D.
and he is a dermatologist, actually, and he also has some reason he had to move
the laboratory. So anyway, I got him last year, and he is also working very
well. Because of this paper, I promoted them from postdoc to instructor, so they
03:10:00are now instructors here.
MEJIA: So are they still in your lab, or do they have their own?
KURO-O: Yes. They are working with me.
MEJIA: And bringing them in, did that help shape your research at all? Did they
bring in ideas?
KURO-O: Yes. For this particular paper, the idea was already there, and they
provided the very nice expertise to prove that hypothesis. They are very talented.
Anyway, after publishing this paper, we needed to go to the next step. The next
step is to identify the Klotho receptor or Klotho binding partner. That was a
03:11:00really challenging project again. Actually, one of the guys, Dr. Hiroshi Kurosu,
the first author of this paper, he actually brought in a new idea. My laboratory
is currently changing direction a little bit because of his great findings. He
found that Klotho protein binds to the fibroblast growth factor receptor. It's a
little bit of a scientific thing. Anyway, he found another protein that
03:12:00interacts with Klotho protein. So, yes, we have been looking for that kind of
protein, Klotho interacting protein, for a long time, and he eventually found
the receptor for the Klotho protein.
So actually, Klotho protein has a lot of functions, a lot of different
functions. So in this paper we described about the involvement of Klotho in the
insulin pathway. But Klotho is also involved in regulation of mineral ion
homeostasis, so Klotho protein can regulate phosphate homeostasis or calcium
03:13:00homeostasis. Klotho can regulate blood levels of phosphate and calcium. That's a
totally new function of the Klotho protein.
I'll tell you about how he found out the relation between Klotho and FGF
[fibroblast growth factor]. So I said that Klotho mutant mice show an aging-like
phenotype, okay? And maybe two years ago, another knockout mouse was developed
and it was reported that they developed aging-like phenotypes. Hiroshi [Kurosu]
03:14:00compared the phenotype of Klotho mutant mice and the reported aging-like mice,
and he found that these two were almost identical. The gene knocked out in the
reported paper was FGF23, fibroblast growth factor 23. These two mice are
exactly the same, not simply resembling, but almost identical. We were really
surprised by this fact, because at the time nobody knew that these two genes
were related at all. If you knock out FGF23, mice get this aging-like syndrome
03:15:00similar to Klotho mutant mice. FGF23, the name shows it's a fibroblast growth
factor which binds to the fibroblast growth factor receptor. FGF is one of the
oldest growth factors identified and very well characterized. As you can notice,
there are many FGF genes. So 23 means the twenty-third identified.
Because of the similarity of these two mice, he [Hiroshi Kurosu] tried to prove
that Klotho is involved in the FGF signaling pathway. He indeed could show that
Klotho can directly bind to the FGF receptor and regulate FGF23 binding to the
03:16:00FGF receptor. It's a kind of co-factor that regulates FGF signaling. This
actually makes a lot of sense, because FGF23 was first identified as a factor
that inhibits phosphate metabolism in the kidney. So if FGF23 is excessive, and
actually there is a disease that produces more FGF23 in humans, it's a
hereditary disorder, but such patients show phosphate wasting from the kidneys
because FGF23 inhibits phosphate reabsorption from the kidney, and they develop
rickets, osteomalacia, and bone diseases.
03:17:00So FGF23 was a very new, recently identified hormone that inhibits phosphate
uptake in the kidney. In the kidney and bone research field, FGF23 was really a
topic in the past one or two years, and Klotho suddenly gets into the spirit,
and Klotho is a critical factor that regulates FGF function. So actually,
Hiroshi and I published the paper about the interaction between Klotho and
FGF23, and it will appear in a JBC [Journal of Biological Chemistry] accelerated
publication this week.
MEJIA: Oh, I don't have that one, then.
03:18:00KURO-O: I'll print it out and give it to you. It's really a hot topic, actually.
MEJIA: That is fast, because you just had two papers. No, maybe that's this one.
So you've had two papers in the Journal of Biological Chemistry since the
KURO-O: Yes. Right. The one is about the follow-up of this study. One of the JBC
papers showed what happens after Klotho inhibits the insulin pathway, after
Klotho increases resistance to oxidative stress, or something like that. That's
a follow-up of a study. But this opened up a different area of the research, so
I'll print out this paper and give it to you.
MEJIA: Thank you.
03:19:00KURO-O: It will appear March 10th, so this Friday.
MEJIA: They did accelerated publication online?
KURO-O: Yes. I think it's already available.
So we have been working on Klotho and the insulin pathway, but another research
direction appears very promising. This is the Klotho protein function in the FGF
signaling pathway. If Hiroshi hadn't noticed the similarity between these mutant
mice, then we couldn't notice this fact. It was really lucky for me to have him
03:20:00here, and actually, that is exactly what I wanted. They are very talented
postdocs. I am already forty-six, and my brain's getting a little bit stiff, and
maybe I need some fresh way of thinking or fresh viewpoint to look at Klotho. I
looked at Klotho only from the aging and insulin pathway thinking, but this
brought me a very different viewpoint about the Klotho protein to look at.
Currently I'm very busy because of this paper, because FGF23 was really a big
topic in the kidney disease field and also in the pediatric research field.
03:21:00There are a lot of mysteries about FGF23, because people didn't know about
Klotho's involvement in this pathway. So FGF23 is actually a very difficult
hormone. If you just add FGF23 on the cultured cell, there is no activity at
all, but if you inject FGF23 in the animal, it is very active. So people assumed
that there was something missing in the cultured cells that was essential for
FGF23 to be functional. We identified that missing factor was Klotho. So if you
inject the FGF23 mice, there is Klotho expressed in the kidney. That's why FGF23
can be functional. But in cultured cells, no cultured cells express Klotho, so
03:22:00even though they applied a huge amount of FGF23, there was no activity at all.
People wanted to know why this happened. So Klotho, just adding Klotho, is
necessary and sufficient to induce FGF23 activity.
MEJIA: In cell culture?
KURO-O: In cell-culture systems. This is about that. This is actually very
interesting because it can be directly applied to patients' treatment. Many
patients with chronic kidney disease will die because of vascular complications,
03:23:00like vascular calcification. The biggest problem in the management of chronic
kidney disease patients is how to reduce the risk of death of such patients. One
of the major risk factors for the chronic kidney disease patient is vascular
calcification. Actually, the Klotho mutant mouse shows extensive vascular
03:24:00calcification and could be a very good model for vascular calcification caused
by chronic kidney disease. So we are currently trying to see whether injection
of Klotho protein--maybe that would be the direct way--might affect vascular
calcification. That's a final goal. So Klotho protein might be applicable to
treatment of chronic kidney disease if Klotho protein can indeed reduce vascular calcification.
You can inject FGF23 as well, but in chronic kidney disease patients, the
03:25:00kidneys are disorganized, and Klotho protein production is very much reduced in
the chronic kidney disease patient. So it's possible that FGF23 injection alone
may not be very effective because there is no Klotho produced in the kidney. In
that case, we need to add Klotho to remove the phosphate from the body, or
There are lots of potential therapeutic applications in Klotho. Vascular
calcification is really a very difficult disease, and no mechanistic insight was
available at that point. Klotho may provide some clue to understand the
03:26:00molecular mechanism of vascular calcification. There are many expectations of
that kind of stuff.
MEJIA: Well, that's real interesting. Because I did give you a heads-up that I
would be about two hours, this might be a good time to break, and I could
actually read the paper this evening, too, if you want. Does that make sense?
MEJIA: Because this is a really interesting area, so I can read this.
KURO-O: Yes, it's another area of Klotho research that just recently came up.
MEJIA: Okay. Well, maybe then we can pick up with this.
KURO-O: Okay. Yes. I'll go and get the paper.
[END OF TAPE 3, SIDE 1]
[END OF INTERVIEW]
MEJIA: Hi. This is Robin Mejia here with Makoto Kuro-o in his office at U.T.
[University of Texas] Southwestern [Medical Center] on March 8th for the third
and final day of the Pew [Scholars Program in the Biomedical Sciences] oral
03:27:00Good to see you again this morning.
KURO-O: Good morning.
MEJIA: When we finished up yesterday, you had been talking about getting to the
point with Klotho research where you had demonstrated that what was going on was
really aging by growing mice that overexpressed and then living longer. Then you
had also started to explain a new direction in your research that had been
picked up on by one of your postdocs [postdoctoral fellows], the instructor
Hiroshi Kurosu. I just took a look at that paper last night. That was pretty
interesting. Are you going to be pursuing any new studies along these lines?
KURO-O: Yes. Right.
MEJIA: Can you talk a little bit about where that will go?
03:28:00KURO-O: Okay. I think Klotho protein has a lot of functions. Klotho protein is a
multi-functional protein, maybe. Inhibiting the insulin signaling pathway is
probably only one of those multiple functions. Actually, very recently another
group published a very interesting paper about Klotho. They are working on some
kind of ion channel expressed in the kidney called TRPV5 [Transient Receptor
Potential V5]. This channel is very important in calcium reabsorption in the
03:29:00kidney. They reported that the Klotho protein can activate this channel through
its enzymatic activity.
Actually, Klotho protein has a homology to an enzyme called glucosidase. It was
extensively investigated in plant biology or bacteria. It is expressed in
bacteria, in plants, and there are lots of family members in glucosidase. Klotho
protein has a weak homology to this enzyme. Klotho protein does not have
enzymatic activity like glucosidase but has a little different type of enzymatic
03:30:00activity called glucuronidase. These enzymes hydrolyze sugar chains, any kind of
sugar chains. The surface protein is usually decorated by sugar chains, and
those sugar chains are very complicated. But recently, those sugar chains are
known to affect renal function or protein function. So in their paper, they
03:31:00claim that Klotho modifies sugar chains on the TRPV5 ion channel, thereby
regulating its activity.
It's a very new concept, actually, so that's why it's published in Science right
after our paper. We didn't notice this fact, but this is really an interesting
finding, because we thought that Klotho functions as a hormone-like substance.
It's also true in this case because they claim that the extracellular domain or
soluble form of Klotho protein can directly impact with this ion channel and
chew up some decorated sugar chain, modify the sugar chain, and regulate TRPV5.
So it's a very new concept, that an enzyme can modify protein function through
03:32:00changing its sugar chain. It's a very new concept, actually. Klotho may be the
first example of this kind of regulation.
Klotho can function as a hormone-like substance. It can also function as an
enzyme, and it can also function as a co-receptor or co-factor that is essential
to fibroblast growth factor-23. There are many faces of Klotho. We don't know if
these functions are related or if these are completely independent functions of
the Klotho protein. We don't know at this point.
There are many ways to approach the Klotho protein function. One of the ways we
03:33:00propose would be to look at the effect of Klotho on the fibroblast growth factor
signaling pathway. That's also probably an important aspect of Klotho protein
function. We can try many experiments to look at Klotho protein function.
MEJIA: You think Klotho will keep you busy?
KURO-O: Yes. Yes, I think so. The new concept [for regulation of TRPV5 ion
channel and calcium ion concentration] they proposed is really, I think, interesting.
MEJIA: Are you talking to that group?
KURO-O: No, not directly, but I'm collaborating with the investigator here at
U.T. Southwestern who is working on this kind of ion channel, and actually we're
03:34:00getting very interesting data, but I cannot yet publish it. We are still
collecting the data. But it's really interesting. So Klotho is indeed a
multifunctional protein, and there are a lot of things to do.
MEJIA: Can you maybe talk for a minute, too, on the bigger picture? Between 1997
and, really, last September you had worked largely independently or with your
own postdocs collaborating here, but probably not many other people outside your
school knew that much about your work at the time, or your results. Then you
published in a very major journal in September that's read all over the world.
Scientifically, what the reaction?
03:35:00KURO-O: Yes. Actually, I cannot handle with all the reaction. Of course, there
were some people working on insulin signaling in the diabetes field who were
very interested in Klotho protein function. That's very natural. But what I was
surprised at was the people who are working on kidney disease or
phosphate/calcium metabolism or the bone-metabolism field were also very
interested in Klotho, because they knew about Klotho mutant mice, which I
reported in 1997, back in 1997 in Nature. They looked at the phenotype and found
that they developed calcification in vessels and in the kidney. So they were
03:36:00very interested in this phenotype. Of course, I didn't know anything about the
mechanism, why Klotho deficiency causes such calcification, but now one of the
Klotho protein functions was revealed last year, and in that Science paper I
proposed that the Klotho may function as a hormone-like substance, so that makes
the researchers in the kidney field think that Klotho may function as a hormone
that prevents vascular calcification or blocks kidney calcification.
And almost at the same time, the FGF23 had been identified, and of course, they
03:37:00are also very interested in FGF23, and this paper linked nicely the Klotho and
FGF23 stories. After the publication of this paper, more and more kidney people
are asking me to work with them. And actually I think it's getting to be a very
exciting topic in that field. So that's probably the biggest reaction and from
two different research fields, diabetes and insulin-pathway field and kidney
disease and bone-metabolism field. Those are the two responses.
MEJIA: So are you hearing from researchers in, maybe, projects that you didn't
even know were happening?
03:38:00KURO-O: Yes. Actually, I have a couple of collaborators here in U.T.
Southwestern after or just around when I published the Science paper, and yes,
so they are, of course, interested in phosphate metabolism and
ion-channel-activity regulation by the Klotho protein. So that's very nice.
MEJIA: That actually kind of brings up an interesting related point. Do you know
how many different labs there are at U.T. Southwestern, roughly?
KURO-O: I think several hundreds, maybe. There are lots of laboratories, and
some laboratories have a number of PIs [principal investigators], but the number
of independent faculty members should be around one thousand maybe. It's a big institute.
MEJIA: I asked you partly because you've mentioned a couple of times that you
have internal collaborations.
KURO-O: Yes. Right.
MEJIA: And those are mostly biomedical researchers of one type or another?
03:39:00MEJIA: So you're probably in an unusual position in this community, in being
able to find a lot of expertise without having to go very far.
KURO-O: Yes, indeed. I'm really taking advantage of this community. The U.T.
Southwestern community is really great. I can find any collaborator. If I have
any questions, I can find people I can ask. That's really an amazing thing.
Maybe if I were in Japan, I could not get this kind of good community. Of
course, Japanese science is really good, but the number of investigators in the
03:40:00similar community or similar institute is probably around one hundred or two
hundred at the most. Even the biggest university, like Tokyo University, the
community is not as big as here. Yes. So anyway, it's Texas, yes? Everything is
very big. I think it's a very good thing.
MEJIA: Is it competitive at all?
KURO-O: Well, actually I'm very surprised. All collaborators are very easy to
communicate with, and we can discuss very freely. We can exchange very
preliminary data and published data in a very effective way. There is no
sectionalism at all. So I am very surprised on that point.
03:41:00But anyway, we are working as a team, and so any interesting data found in any
member of the team, the group or team can share when it's by anybody and develop
another hypothesis, another way to experiment. So yes, I think it's very good. I
think we are making a very good research team on Klotho protein function and on
kidney function or phosphate metabolism. That's very good.
MEJIA: Let me just flip back here, if you don't mind, for one sec.
03:42:00MEJIA: Well, the other questions I wanted to ask: You have a largely research
position, but you're in the university, are you on a fairly traditional tenure
KURO-O: Yes, I'm on the tenure track, actually I will be promoted this September
to tenured associate professor. Otherwise, I might have to go back to Japan. But
I can continue the Klotho work here.
MEJIA: Yes. I'll bet they want to see you continue it here at this point.
Well then, that kinds of leads me to more of a big-picture kind of question. You
mentioned yesterday that as you become a professor, you take on more
responsibilities than just getting your science done.
03:43:00KURO-O: Right. Right.
MEJIA: Can you kind of talk about how that's changing? Are you going to be
KURO-O: Yes, right.
MEJIA: Do you review papers for journals or do study sections or anything?
KURO-O: Yes. Probably one of the most important works as PI is to get enough
grants to run the laboratory. Of course, there are many other things to do, to
provide a good research direction and research topics for postdoctoral fellows
or students. Of course, there are some teaching duties and much paperwork to
03:44:00maintain the laboratory and many such kinds of stuff. But all those things would
be very easy if we are doing good science; because if we have good research
topics, we can get grants and I can provide good research topics to the
postdocs, and everything will be working very well.
In these two years, I found a couple of interesting research directions in
Klotho. So I believe I'm doing pretty good science right now. Currently I'm a
03:45:00little bit optimistic about the future, about getting grants or getting good
people. But it's only this year or last year. Before that, I was really worried
about what direction we should go, and I was always asking am I doing good
science or not, or something like that. But in these three years, I think, I can
get good collaborators, and I can see a couple of very promising research
directions. So in that sense, I think it's okay, it's okay.
But I am getting a little bit busier arranging collaborations or doing more
grants writing, and maybe teaching duties will be increasing in the next year. I
03:46:00may not spend a lot of time to the research itself, but I think it's the natural
way to expand my laboratory a little bit.
MEJIA: That makes sense. At this point, have you still been involved sort of day
to day in doing the science at the bench? Are you still at the bench?
KURO-O: Oh yes. I'm working at the bench, recently maybe 50 percent of my time.
So three years ago, I spent 90 percent of my time at the bench making data and
maintaining mice. My laboratory is still very small. I have three postdocs, and
that's it. So actually I'm the only person who works on the mouse colony. I
maintain all the mouse colonies and make recombinant Klotho protein. My basic
03:47:00idea is, what I should do at the bench is probably provide good material and
good reagents. The postdocs can use those reagents and get interesting data or
do the experiments.
I think a small laboratory might be similar to a small restaurant, actually. So
maybe the owner--that's me--should get good ingredients from the market and get
good decoration of the interior or setting up all the tables. The postdocs
should be the chefs. So then I can provide great materials, and then they will
03:48:00make very nice dishes. Then the restaurant will run very nicely. That is maybe
similar to running the laboratory, small laboratory. Maybe some of the postdocs
are very good and can make better dishes than myself. In that case, maybe I
don't need to worry about that, just give them the good material. Then they will
cook very nicely.
My role in the laboratory is changing. At first, I just behaved as a chef, and I
needed to make the dish by myself. But if the laboratory is getting a little bit
bigger, I can hire good chefs, and I can just leave them everything and just
03:49:00arrange the environment so that they can work competently. That would be
probably the best way to run the laboratory.
MEJIA: With the paper we were talking about earlier and with the fibroblast
growth factor work, did he [Hiroshi Kurosu] bring the idea to you, and you guys
discussed it, and you said, "Go for it"?
KURO-O: Yes. Right. So the first thing that Hiroshi noticed was the similarity
between the phenotypes of the Klotho mutant and FGF23 knockout mice. That was
the beginning of this idea. So of course we discussed a lot what kind of
03:50:00experiment we should do first. But it's pretty straightforward. If two mutant
mice show an identical phenotype, then these two genes must be related to each
other. The question is which is upstream and which is downstream or something
like that. Or they might be working together.
MEJIA: How does it work when you get to the point of publishing? Who wrote the paper?
KURO-O: I wrote the paper. I'm a little bit more experienced in writing than
Hiroshi, who was the postdoc. That's why I wrote it. I got informal information
that some groups in Japan might have noticed a similar thing. I didn't know how
03:51:00much they knew, but we needed to hurry up. So we worked effectively together. He
did the experiments, generated the data, and I was writing the paper and
organizing the other data and what data is missing or something like that. We
interacted extensively, and all the lab members helped him to get the data.
Actually, this was a really quick paper. It took only, maybe, three or four
months to get all the data from the beginning to the submission. It was pretty
quick. Yes, it was a really nice interaction with the postdocs and myself, and
03:52:00they did the things they are good at.
MEJIA: What kind of hours do you work now? From morning till night. What's a day
like? Walk me through a day.
KURO-O: I'm an early bird. I'm in around seven-thirty and work about eleven to
twelve hours and leave the office around six-thirty or seven-thirty. It was much
better than when I was in Japan, you know? I worked sixteen hours when I was in
Japan. But I'm getting older, so twelve hours, eleven hours would be more than
enough, maybe. But as I said, my laboratory is still very small, so there is
lots of work to do, daily work to do.
MEJIA: Can you maybe describe a typical day? You arrive at seven-thirty. Then
03:53:00what do you do?
KURO-O: Maybe I usually spend time doing experiments or taking care of the mouse
colonies. I'm getting a lot of e-mails about collaboration, so I spend most of
the time in the morning communicating with other investigators or arranging a
collaboration or reviewing new data.
In the afternoon I usually do some experiments. My duty in the experiments is to
03:54:00purify recombinant Klotho protein and provide the protein to my collaborators
or, of course, my postdocs and to maintain the mouse colonies and provide mice
to collaborators and postdocs. Or sometimes they need tissues of the mice, and
then I do the dissection and provide it to them, something like that.
It's very different from day to day. Some days I have to spend most of my time
in the laboratory. Just before the grant due date, I have to spend almost all
the time here, writing up the grant. It's quite flexible.
Actually, I just completed continuation of my R01s last month. So last month was
03:55:00really hectic. I had to spend most of my time writing up the grant.
MEJIA: So you finish up at six-thirty or seven-thirty?
MEJIA: Do you usually just go home for the evening?
KURO-O: Yes. Right.
MEJIA: Do you have any hobbies?
KURO-O: Well, I'm trying not to come to the office on weekends, as much as I
can. I try to spend time with my wife [Kumiko Kuro-o], because, yes, weekdays I
cannot spend much time with my wife. It's a very normal weekend. I just go
03:56:00shopping with her or just go to see movies. It's pretty normal.
MEJIA: Let me just check. We've got some time left.
I just want to move back to the science again, for a little bit, because I was
thinking about it. At the end of yesterday, you were describing how the new
Klotho work may tie in to disease applications. Can you give me a better sense.
This is still basic research, at this point, right?
MEJIA: Is that something that might lead to treatments ten or fifteen years out
or three or four years out? Do you have any sense of that at all? Are you
03:57:00thinking along those lines or not?
KURO-O: Yes. So, yes, of course, the long-time goal would be to use Klotho
protein to treat, or to suppress, the aging process in humans, but I don't know
if that dream could come true in the next ten or twenty years. Or if you could
find some small molecular weight mimetics of Klotho protein, then the mimetics
could be applied to the treatment of chronic kidney disease. That's probably the
one that's the closest application of the Klotho protein to humans.
03:58:00Before that, a more practical way to use Klotho research to patients' care is to
measure blood concentration or urinary concentration of Klotho protein. Klotho
protein is secreted in the blood or excreted in the urine. We are currently
working on the method to measure blood and urinary Klotho protein concentrations
in clinical support. And if you can find any correlation between Klotho
concentration and some specific disease conditions like kidney failure or any
kind of age-related diseases, then that would be useful for diagnosis or
deciding the prognosis of such age-related diseases. So that might be a pretty
03:59:00close goal, because we have almost finished establishing a method.
The next step would be to collect as many clinical samples as possible and
measure Klotho protein concentrations in those samples and see whether any
correlation might be observed in some renal disease. And the next step is, if
Klotho protein is indeed useful in preventing vascular calcification or kidney
failure in the chronic kidney disease patient, then Klotho protein itself or
Klotho protein mimetics might be useful. That could become true within ten years
or so. I don't know.
04:00:00MEJIA: When you move from the real basic questions into looking at developing a
diagnostic or eventually a drug--and therapy with a small mimetic would be,
right?-- how does the intellectual property work? Do you or the university
patent any of these ideas, or how does that work?
KURO-O: If we can find any such compound, then that would be really good
intellectual property, but at this point I don't know whether I can find it or
not. I don't know very well about how the patent works or how intellectual
property works, but if that helps me do more basic research, that would be
great. If the university can get some advantage because of my Klotho research,
04:01:00that would be very great. I got a lot of things from the U.T. Southwestern
community, so if my research is useful for the U.T. Southwestern community, that
would be great. But at this point I have no idea.
MEJIA: Okay. It's still early for that.
KURO-O: Just doing basic research right now.
MEJIA: Do you do any consulting at all?
KURO-O: No, I don't. I just sometimes receive journal reviews. That's all.
MEJIA: I'm just curious, because actually, among the researchers I've talked to,
most are basic researchers, whereas you can see a long-term application. From
the last thing we talked about yesterday, it sounds like you could potentially
04:02:00KURO-O: Yes. Right. It's still a potential, maybe. I've been contacted by some
pharmaceutical companies, but still the Klotho research is basic research, and
it still has a long way to go to apply to developing drugs and medicine. So,
yes, they are interested; the pharmaceutical companies are interested in Klotho
because their research interest is similar to my research interest. Getting some
drugs or developing some new drugs, it's maybe a little too early to discuss
about that. We still need to know what the Klotho protein is doing right now.
MEJIA: It sounds like one challenging thing about Klotho protein might be the
fact that it does so many things.
KURO-O: Right. Exactly. Maybe we are looking at the Klotho protein from a
different angle. Klotho inhibits the insulin pathway, regulates the FGF
04:03:00[fibroblast growth factor] pathway, regulates the ion channel. If the enzymatic
activity of Klotho is really essential to all these functions, then we can focus
our effort to look at Klotho as an enzyme and see what regulates Klotho protein
enzymatic activity. At this point, I don't know what is the closest way to reach
to the core part of the Klotho protein function. We have several ways to go.
That's a good thing.
MEJIA: That makes sense. I think that's not an uncommon route, to find something
that's naturally active and see if you can tease apart the pieces. I think it
took ten or fifteen years from when people started looking at cannabinoids, and
now they've finally got drugs on the market.
04:04:00KURO-O: Yes. I hope so.
MEJIA: They related the pieces of it.
MEJIA: Okay. I think we're ready to change the tape. I'm just going to flip this.
[END OF TAPE 4, SIDE 1]
MEJIA: This is Robin Mejia still here with Makoto Kuro-O on the second side of
the fourth tape.
We just talked about eventual medical applications, and you've mentioned a
couple of times today that you feel like you have a handle on several distinct
interesting research directions. And I noticed from your CV [curriculum vitae]
you have two, or one now, [R01 grant]. You mentioned one you just submitted for
renewal, and you have other grant ideas. How do you see yourself moving forward
in the practical matter? Do you need to recruit more people, or are you going to
stick with your lab size? What are you going to do? How are you going to move
this all forward?
04:05:00KURO-O: I want to expand the laboratory, indeed, because there are a lot of
interesting topics there. But another way to go is to expand my collaboration in
U.T. [University of Texas] Southwestern [Medical Center], and that is, I think,
probably the best way to go, because I don't need to get so many new grants to
expand my research, I can just talk with other people and expand the
collaboration, so they can expand the research using their own expertise. And if
I can collaborate with clinicians, they will take advantage of their access to
the patient sample for the patient data.
04:06:00I think Klotho research will expand in various ways, and maybe only a single
laboratory cannot handle everything. Maybe my laboratory should focus on the
very basic part of Klotho protein function itself, and then I can expand
collaboration with faculty at U.T. Southwestern. There are lots of patients
visiting this area, so I believe we can do a good clinical study. I'm not so
experienced for that kind of study, so maybe I should find a good collaborator
and work with him or her.
MEJIA: This would be maybe looking at the diagnostics?
04:07:00KURO-O: Yes. For example, if I can have access to blood samples or urine samples
of chronic kidney disease patients, that would be very interesting. Some doctors
may have access to some cancer patients or some lung-disease patients. Anyway, I
cannot imagine how many patients are visiting every day here at U.T.
Southwestern, but I think maybe this is a very good place to do both basic and
MEJIA: Up until now, all your Klotho work has been in mice, right?
04:08:00KURO-O: Right. Exactly. Right. So in mice, I know how to handle mice, but I
don't know what kind of study is possible using clinical samples. Some studies
might need collaboration with patients themselves. I don't know how to arrange
those studies at this point. Because of this, I really need a good collaborator
who will be very familiar with that kind of research design and study. But maybe
we can do that. Actually, one of my collaborators is doing both basic research
and looking at outpatients, and he has access to lots of clinical samples. So we
04:09:00are talking about measuring in blood and urine Klotho protein concentration
using those samples. So yes, actually the collaboration has just started
recently, so maybe we can get some data pretty soon.
MEJIA: Has anyone done that: confirmed that you see the same activity in people
that you do in mice, or no?
KURO-O: Well, maybe no, maybe no, because we are probably the only laboratory
that can measure blood and Klotho protein concentration at this point. So no
laboratory can do that at this point. I don't know about two years later.
MEJIA: Right. Probably more people are looking at Klotho right now than were
this time last year.
KURO-O: Yes, I think so.
04:10:00MEJIA: I have a few more big picture questions I want to get to. You seem to
have a pretty solid sense of going forward. If you were going to look back on
your career path, reflect, and say you were talking to somebody at the postdoc
[postdoctoral fellow] level today, do you have any particular thoughts on things
you might do differently, or not, or some advice you'd want to give someone
about how to do this?
KURO-O: Well, all right. I don't know. Seriously, I think I did what I could do
at each career stage. If other people found the Klotho mouse, noticed the mutant
04:11:00mice that showed aging-like phenotypes, other people may have responded in a
different way. Some people might have just thrown them away, or some people
might have done much better than me. Actually, my career was influenced by
coincidence a lot. As you know, I did not intend to devote myself to aging
research. I'm here because I happened to get the mutant mouse. It was an
accident. It was just an accident, a coincidence. But my career was influenced,
and my present state was not as I imagined when I was a high-school student or I
04:12:00was in the university. But I think it's okay. That's life, maybe.
MEJIA: One thing that came up several times when you were describing your career
trajectory was the hours and the amount of time, which is, I think, probably
similarly true to people going through the early stages of their career
trajectory in the U.S. [United States] as well as in Japan. But it brings up
another issue that's been in the news, that a lot of organizations are looking
at lately, which is both women and minorities in science. Working in the U.S.,
you have more experience with the second one.
KURO-O: Yes. Right.
MEJIA: But a lot of times the career trajectory calls for the longest and the
craziest hours right through somebody's late twenties and into their thirties.
04:13:00Do you in particular, or do you know if this institution has any particular
thoughts on women in science right now? Do you see very many women coming
through towards senior ranks here?
KURO-O: Certainly in the case of the University of Tokyo, my class had one
hundred students in one class, and only three of them were women. Actually, it's
always like that. So 95 percent or more were male students, and the women were
very rare. From the beginning, there was a huge bias, so naturally, all the
04:14:00careers are men.
In a sense, all careers helped women, because, traditionally, in Japan, M.D.'s
were all occupied only by men, maybe from more than a hundred years ago, from
the beginning of when the modern university system started in Japan.
Actually, I didn't have a chance to think about the minority problem or women
04:15:00problem, because it's too minor. The minority problem will be a problem if a
minority group occupies, say, 10 percent of the population or 20 percent of the
population. If it's only 1 percent or 2 percent, we rather try to help or
protect. There's no official rule or official regulation how to solve the
problem about minorities or the gender problem. I don't know. Actually, I don't
have any chance to work with women doctors, so I have no idea.
In addition, in Japan there is no racial problem because there is only one, the
04:16:00Japanese race, over there. No foreigners at all. So it's quite an unusual world
there. But in that sense, the Japanese have no sense of racism. I really think
so because of what I felt when I first came to the [United] States. I was very
poor at the English, and I couldn't make myself understood, say, at McDonald's
or a hotel. Can you speak Japanese, maybe?
04:17:00KURO-O: So, if you came to Japan, if you said something, tried to say something
in poor Japanese, then Japanese people would try to understand you and try to
talk to you in English, even though they are very poor at English. But that
could never happen here in the States. When I was using poor English and trying
to communicate with some people, usually they never spoke slowly or tried to use
easier words, but just, "I'm sorry. I can't understand you." Then they would
just repeat the same thing, and, of course, I couldn't understand that. So maybe
04:18:00they cannot understand the people who cannot speak English. So maybe that's a
point of miscommunication. They cannot imagine what is the state of those who
cannot understand what people are saying. You know what I mean? So probably
that's why they simply thought that I couldn't hear them very well or something,
and they would just repeat the same thing. But what I really wanted them to do
was to speak more slowly or to just write down what they said. I can read, so
once it's written down, I could probably understand. Anyway, so the topic is
going in a different way.
MEJIA: No, that's good.
04:19:00KURO-O: But in that sense, I grew up in a very homogenous society. There were
not so many problems about racial difference or minority problems. And of
course, I was in an almost 100 percent male world; there were no women, so I had
no chance to think about it.
MEJIA: It sounds like, maybe, actually, the cultural bias against women pursuing
science careers would be stronger in Japan than here.
KURO-O: Right. Exactly. I imagined that the United States would be a more
heterogeneous society, and in fact, there are many women scientists working
04:20:00here, and there are many people from different countries and different cultures.
So I think that's sometimes really very stimulating, to know a different way of
thinking or to know a different culture. But sometimes, of course, there is some
miscommunication, or something I thought would be good for them might not be
good for them or something like that. That could happen. But the good thing is,
we are doing science, so science is really science. It's good training for me to
explain my data or my concepts, so it's easy to understand for any cultural background.
MEJIA: Do you have any female collaborators here that you're working with?
04:21:00KURO-O: At this point, yes, I have a woman collaborator, not here but outside,
in another university. I think we are working very well.
MEJIA: Now, one thing that people have looked at and found is that in the U.S.
there seems to be fairly equal representation in most fields up through graduate
school and postdoc level, and it's getting into the tenure-track and full
professor positions that the drop-off with women tends to happen. The hypothesis
is that it's because the most intense period of the career is the same time
people have to decide if they want to have kids or not.
KURO-O: Right. Exactly. That's a big factor.
MEJIA: Because if you wait till you're in you midforties and are more settled in
your career, you very well likely may have missed your window for children.
04:22:00KURO-O: Right. Yes, exactly. That's, I think, the biggest factor.
MEJIA: Just to follow up on the other thought, when you came here, did you find
that communication was an issue in doing science as well, or mostly in your
day-to-day other parts of life? When you were getting established and trying to
understand the American system, did that pose challenges at work, too?
KURO-O: Well, actually I didn't have any big problem in learning how the system
works in science, because all people knew that I didn't learn about this system
so people helped me a lot. Even if I had a very ridiculous question for them,
04:23:00they taught me very well. But I think the system here is very reasonable and
understandable. Yes, a similar system actually exists in Japan, but in a sense,
the Japanese system is a little bit more bureaucratic. You have to do a lot of
paperwork. Sometimes it seems a little bit like nonsense.
But I think the system here is working very well so that we can focus on
science. I think the system is very mature here. At first, I just took some time
04:24:00to understand how the system works, but once I understood the system, it was
actually very nice. So, I can spend more time, not for the paperwork but for the
science. I can spend much more time. I couldn't do like this if I were in Japan, maybe.
In the Department of Pathology, at least, there are lots of people working to
support our research, like secretaries and pathology technicians, and the
chairman of department has very strong support people, and they actually can
04:25:00take care of most of the nonscience part of my job. So that helps me a lot, indeed.
MEJIA: What's your residency status? Did you apply for citizenship, or are you
here on a visa?
KURO-O: I got a Green Card [permanent residency card] last year. It took three
years for that route.
MEJIA: That's pretty fast.
KURO-O: Yes. Yes. It's still very fast, I think, yes. So I first got H-1B [visa]
when I came here, and it's valid for six years, and after six years, I had to
choose whether I got a Green Card or go back to Japan.
MEJIA: Do you see your research keeping you in the U.S. indefinitely at that point?
KURO-O: Yes, at least for a while. I can survive for a while. I will get tenure.
04:26:00And as long as I can get funded, I can continue working on Klotho here.
MEJIA: Is that your preference at this point?
KURO-O: Well, yes. I just expanded my collaborations here, so I would like to
stick here for at least the next several years. But I don't know what happens
after ten years or seven years. But I'm very, very satisfied in the current
funding situation and collaborators, so I don't feel like moving anywhere at
MEJIA: That makes sense. I just asked because I remember at the beginning you
had said you had never intended to even look in the U.S.
KURO-O: Right. Maybe I'm lucky. I didn't see anywhere else, but I think this is
very good here for me.
04:27:00MEJIA: Well, we have actually covered, I think, most of the stuff that I
specifically wanted to ask you. Were there other areas? Was there anything that
you wanted to address about science or your lab or your students that I didn't
think of asking you? The state of science in the U.S. as a whole?
KURO-O: Maybe I should comment a little bit about the difference between the
Japanese system and the United States system.
MEJIA: That would be great.
KURO-O: Yes. I remember that the total budget for science spent every year is
more than ten times more here in the States when compared to Japan. That's a
huge difference. Recently Japanese science is getting much better than before,
04:28:00and the government invests more and more money, in the past maybe five years or
so. And the Japanese system is getting better and better recently. But still,
the total budget is less than one tenth. That makes a big difference. And of
course, the quality and quantity of the science, or the publication of papers,
cannot compare with the United States. Everybody knows that the United States is
in the number one position right now. In that sense, it's very lucky for me to
04:29:00be here and work in the States. But I don't know when but in the future, I would
like to contribute to Japanese science in some way. Of course, they are two
different countries with a different historical background, and there're
different budget systems, so it's probably wrong to directly bring the United
States system directly to Japan, apply to Japan its system. But maybe what I
learned here can be of some help to improve the Japanese system.
So I don't know when it will be, but maybe five, seven, ten years later, I hope
I make some contributions to improve Japanese science, the system, because I am
04:30:00Japanese, and my cultural background and my scientific background, all the
education, was done in Japan. So I'd like to contribute in some way to Japanese science.
Nowadays, many Japanese scientists work here in the United States and get back
to Japan, so I may be just one of them. But we have, probably, a lot to learn
from the United States science system. But, that's what I am lately thinking
about the long-term future.
MEJIA: That's interesting and makes sense. It's a challenge, probably, because
I've heard from other people that have come to the U.S. to do science that it's
04:31:00by far easier to do science here, as so many smart people come from everywhere
to do science here.
MEJIA: That's interesting. So you may yet end up back in Japan.
KURO-O: Maybe. If anybody can provide me a good position there.
MEJIA: Well, no. There's much to said for being someplace where you've gotten
research done that contributes a lot to the global scientific understanding. You
were able to do it here, so there's a lot to be said for that.
KURO-O: Right. So maybe I can do the same thing, not maybe the same thing, but
we can continue Klotho work anywhere, maybe. Anybody can start Klotho work
anywhere. Science is like that.
04:32:00MEJIA: But yes, it helps to be in a place where you're getting it established,
though, financial support and the freedom you've got here.
KURO-O: Yes. Right. It took a lot of time and effort to get the current
situation, so I'll be several years here, at least.
MEJIA: Great. Well, thank you so much.
KURO-O: Thank you very much.
[END OF TAPE 4, SIDE 2]
END OF INTERVIEW