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What's cookin' in the lab?
Basically we're looking at the ways that certain kinds of proteins are manufactured by different cells. Part of the mechanism for producing a lot of different kinds of proteins that cells make is to initially synthesize them as larger molecules that then either have to be processed either inside the cell of origin or after secretion from the cell of origin, to smaller molecules, which are actually the bioactive components. What we are studying are actually those processing events and the enzymes that mediate the breakdown of the larger molecule into the smaller molecules that are the actual biologically active substance.
We're currently trying to identify and utilize inhibitors of these enzymes that are responsible for breaking down the larger molecules into the smaller molecules. If we're successful in first finding proteins that do this, and then developing methodologies for putting them into cells so that the cells actually manufacture them, in the same cellular compartments where the processing actually takes place, then that methodology could actually be very useful in combating several prominent disease processes, such as cancer or AIDS.
So that would be pretty important, if we could get to that point. We're partway there; as I said, we have identified several proteins. The key issue is that the inhibitors themselves are actually proteins- they're not some chemical that's been manufactured in a test tube that would not normally be found in a cell- because it's difficult to get such substances inside a cell in a living organism. What we're trying to do is to get the cells to manufacture a protein- one that they would not normally manufacture, that would, once inside the cell, inhibit a processing event that normally occurs, and in so doing, in cancer cells for instance, would inhibit the production of proteins that normally self-stimulate.
Many types of cancer cells differentiate to manufacture proteins that they would not normally express. Some of these proteins actually act back on the cancer cell and stimulate their growth. So if you could stop that vicious cycle, you might slow the rate of growth in cell division in cancer cells. The approach in AIDS is similar but different. The HIV virus, once it infects cells Ðand the cells that are infected are usually cells that are found in the blood, cells that are responsible for mediating immune responses- then it takes over some of the cellular machinery to make some of its own proteins. One of the proteins that's made is called a coat protein. It also is manufactured as a larger molecule that has to be broken down into two smaller molecules in order for the coat to re-form. One of those proteins actually serves as a component of the viral coat that is responsible for initial contact with cells that are infected with the HIV virus.
It's been found that if you block the breakdown of the larger molecule into the two smaller molecules, that the coat proteins don't form properly, and therefor the virus is not capable of infecting additional cells. So if there were a way to block the processing event, and a key issue is that the processing of this larger molecule actually takes place inside the cell that's been infected, and uses enzymes that are normally used to process cellular products. The same enzymes we've been studying for years that manufacture peptide hormones and other types of bioactive proteins. So the methodology of blocking those enzymes would also be applicable in cells that are normally attacked by the AIDS virus.
By what mechanism do you induce the cell to manufacture this agent?
We have cDNA's- complimentary DNA that have the genetic code for these inhibitor proteins. And if you put that cDNA into something called a vector- more specifically a mammalian expression vector- and this is another piece of DNA that can be put into cells by a process called transfection, it becomes integrated into the nucleus and becomes responsible for making the cell manufacture this new protein that it didn't formerly make.
The vector that we're using actually goes one step further and causes the new product that's being made by the cell that's been transfected to be targeted into the pathway that is used for proteins that are exported, which is where the processing enzymes reside. So the idea is to get the inhibitory protein into the same cellular compartment, where the enzymes that we want to inhibit are actually working. In other words, you would then make cells manufacture this protein that it doesn't normally make, that would then make it resistant to additional attack by the virus.
The virus initially could attack the cell, but the replication of the virus would be inhibited because you're stopping the production of two important proteins that are necessary to remanufacture the viral coat. First of all, the virus can't replicate itself completely, and that faulty virus is then defective. That's the theory.
How does such a vector work in vivo? In other words, how can you make this work in a living person?
What one would like to do is to work on a stem cell- a cell that differentiates into one of these immune- competent cells. More specifically, the cells that are normally targeted by the HIV virus are called CD4- or CD8-positive cells. That means they have certain kinds of receptors on their cell surface that this coat protein can interact with. That includes things like T4 lymphocytes, which are cells that are responsible for cell-to-cell interactions, and destroying these non-cell type cells that get into the bloodstream. Also, the so-called monocyte macrophage series- these are cells that are phagocytic and gobble up bacteria and other kinds of things. So those are the two main cell types that are normally infected by the HIV virus. The idea would be in order to get some of these cells into the circulation of an individual who might already be infected with aids, would be to transfect in vitro- in testtube or culture dishes- stem cells. These stem cells, once introduced into an individual, would then transform into these end-stage cells, such as the t4 lymphocytes and monocytes. They would then have the capability to manufacture the inhibitor. What we'd like to have is a latent type of cell that would not be making the inhibitor, because if the cell's not infected we'd like it to go ahead and perform its normal function.
There are proteins that are made by the virus itself that stimulate replication of the viral proteins. So if you could put the target site of those proteins upstream from the cDNA in the vector, then you would have a latent situation in which the inhibitor would only be expressed if the cell was actually infected by the virus, and the virus is making the stimulatory protein.
What is the state of the art in this kind of stem-cell genetic engineering?
People have had difficulty in culturing stem cells, but there are a number of laboratories working on just that sort of thing. Just recently, several laboratories have reported success in culturing stem cells, and one really promising area is placental chord blood. Chord blood turns out to have in it a rather rich population of cells that have yet to differentiate, and will then become different kinds of lymphocytes, different kinds of monocytes, and even other kinds of lukocytes such as neutrophils and acinophils and other cells of the immune response system.
You may have read in the lay literature lately a remarkable success right here at Emory in which chord blood was used to transfuse into an individual who had a very severe problem with sickle cell anemia. That young man is I think three or four months past his transfusion, and apparently doing fairly well. So some of that kind of expertise is actually here on campus. In fact I know the investigator who is responsible for that. We talked about, possibly down the road, when we get the methodology down, collaborating to see if we can put our vector with the inhibitor coating sequences into stem cells. That would be the approach that would be used for AIDS.
Cancer would be a bit more difficult, because how do you design a magic bullet that would target the vector only to cancer cells, which would be necessary. That, I think, is going to be a little bit more difficult to do. People are working on that sort of thing as well. It turns out that cancer cells also express on their surface specific kinds of proteins and carbohydrates that aren't normally expressed on normal cells. So theoretically those could be used as sites for targeting. That's a little bit more difficult than doing it systemically, because you couldn't be sure that you weren't infecting other cell types.
But that's down the road- that's not something that's going to happen tomorrow. We're basically at the first stages of this, and we actually are testing the methodology in cells that are not even blood cells. We're testing it in cells that make a protein hormone that we've worked with for a number of years, and we have a lot of information on it, and just seeing if the methodology works, by putting the vector into cells that normally make a larger precurso molecule that's processed to a smaller molecule and seeing if we can inhibit those processing events. You have to test the methodology first to see if it works.
This stuff is way down the road- it's the ultimate goal. The methodology has yet to be proven, and if we can't make it work, then all of this is a pipe-dream.
Tell us about your education to date.
I got into this career in a completely backwards fashion. I didn't even know this career existed when I went off to college. I grew up in a farm in the Midwest. Some of my contemporaries didn't even finish high school, and just stayed on the farm, and became family farmers. My parents were adamant that I was going to go to college, and pushed me out the door after I went to high school. Somewhat reluctantly on my part, actually.
I had no idea what I was going to do or why I was going to college or what I would do with a college degree. I do have kind-of an unusual background. I really wasn't interested in much of anything the first couple of years and took liberal studies-type coursework. Then, either the end of my sophomore year or beginning of my junior year, I got into biology and really enjoyed it. Then I decided, at that late date, when I became a junior, to major in biology. I took all my major courses in my junior and senior year.
I didn't know what I was going to do with a biology degree, and one logical thing was to teach high school, so I also took all the education courses at the same time. I got my education certification.
But then I student-taught at a high school. That was one of the worst experiences of my life. That was the spring of my senior year. I really didn't like it because these kids were not interested. If I knew then what I knew now, I could have made it more interesting and engaging, but as it was I was bored and they were bored.
So I didn't know what to do, but fortunately I went to a small school where the faculty and the students had a lot of interaction, and the chair of the biology department called me in April of my senior year, and he said 'What are you going to do next year?' And I said, 'I don't know, because I really don't want to teach high school.' And he said 'Well what about graduate school,' and I said 'Well what's that?'
I said, 'Well, you know, I'll try it.' He was able to get me in even though I hadn't applied at that point. He got me into a master's program at a school where he was pretty well known. I really enjoyed the coursework I took and I also had a teaching assistantship, and I enjoyed teaching college students. So I decided, 'Well, I'm in school- why not stay in school and get the doctoral degree because if I want to teach in college, I'm going to have to have a Ph.D.' And this was a Master of Arts degree, so I still hadn't done any laboratory research.
I applied for a fellowship at the University of Minnesota, because they had a pre-doctoral training grant at that time, and went into a Ph.D. program there. That's where I got my first exposure to laboratory research and I realized that I really enjoyed being in a lab. My farm background served me well, because I had grown up doing mechanics and fixing things and tearing stuff apart, and there are lots of laboratory things that require that kind of knowledge and expertise. I really enjoyed doing research.
I got into a project that was related to what we're still doing. My dissertation project was to ask the question, 'Is Glucagon, Which is a Pancreatic Hormone, Produced in Pancreatic Eyelet Tissue, Synthesized by a Precursor Molecule?' This was 1968, which was the year in which protein precursors were discovered. I was in graduate school when Pro-Insulin was discovered and I was really intrigued by the idea that cells would make something bigger and process them into smaller molecules that are the bioactive components.
So my dissertation, as I said, focused on asking if another peptide hormone, also produced in pancreatic eyelets, is also manufactured as a precursor. The bottom line was yes, it was, and since that time, it's now known that essentially every peptide is synthesized by a precursor and a lot of other molecules as well, like cell-surface receptors and other proteins that are not even exported from cells.
So I stayed on at the University of Minnesota for a post-doc and was a part-time instructor after I finished my Ph.D. I went into the job market wanting to be in an academic institution. I had a number of different job offers, one of which was here. There was a new chairperson at that time who had only been here several years, who wanted to develop teaching of medical students in a much less didactic and a much more interactive manner; incorporation of function in addition to structure. That appealed to me.
I got involved with two other young faculty when I first came here, which was 1972, and we developed a much more integrative and functional approach to teaching cell biology and histology to first-year medical school students. I've been in that course now for 26 years, and am now co-director of that course, and we've evolved it over the years to the point where we've incorporated a lot of computer-aided instruction. In fact almost all of our laboratory, which used to be just sit down at a microscope and look at slides, is now almost exclusively on the computer and on the web.
So students can do their laboratory work at home, or in one of the Cox Hall computer stations, or we have computer stations over at the Dental building, and also at WHSCAB for the medical students to use. It saves them a huge amount of time, and it saves us a huge amount of time. We've cut back on our faculty hours in the laboratory because a lot of this they can do on their own, and they just come in and we answer their questions.
Some of the other courses have now tried to pick up on this approach; to copy what we've done. Now, in addition to my teaching and laboratory responsibilities, since 1991, I've been director of the graduate division of Biological and Biomedical Sciences.
It consists of eight separate inter-disciplinary programs, and comprises basically all of the bioscience Ph.D. training at Emory. There are no departmental bioscience training programs at Emory; all Ph.D. training is inter-departmental. Right now we have something like 260+ faculty involved in the eight different programs, and approximately 300 students. After the department of medicine and the school of medicine, if you look at it as a department it's as if it's the biggest department at Emory. It's not really a department, though; it's a component of the graduate school. It's called the division of biological and biomedical sciences.
That's a half-time job. I spend my afternoons over there and my mornings here, and I still teach and still try to keep a lab going. I don't have a lot of spare time.
How do you balance so much?
Well, I kind-of take the attitude that I do whatever I can. I work long days- I'm here at 6:30 every morning. I'm rarely home before 6:30 or 7:00 at night. So it's basically twelve-hour days. Sometimes on weekends when it's necessary. I don't take a lot of time off, and I basically keep at it as hard as I can. Then, when the day's over the day's over- I try not to take it home.
I used to work a lot on the weekends, but I've cut back on that. I have to be a human being- I have a family, and I spend some time there, and I spend some time with myself. I play tennis, as my primary activity, and as soon as my knee gets better I'll be doing it again.
I think I've been able to balance it. I think there were times when I was younger when it would have been nice to have more time to myself. Even though I have more responsibilities now than I think I ever have, I think I'm doing a better job of managing it than I did when I was younger. Life is too short to lock yourself up at work.
This profession is demanding. If you're trying to talk to young people who are thinking about becoming scientists, I think they need to be aware that you have to really like it. You can't be successful in science and work a 40-hour week. It's too competitive, and there are too many details you have to attend to. It's not easy- you have to love it.
It takes a long time to get to where you want to be in terms of a permanent position. Our mean time to degree for the bioscience trainees here in these programs is five and a half to six years. And if you want to go into an academic position, you have to have at least three to five years of postdoctoral training after that. And at that point it's still quite competitive. We've had several faculty positions available over the past couple of years, and the last time we advertised for a position we had over 400 applications for that position. And there are a lot of high-quality folks in that pool. So it allows you to be very exclusive in terms of the expertise you want to choose, and the specific individuals that you bring in for interviews.
On the other hand, there are lots of opportunities in science. Less than 50% of Ph.D. bioscience graduates in this country end up at academic institutions. The explosion of the biotechnology fields, the pharmaceutical industry, there are spinoffs in other kinds of professions, like a number of people who I know who are trained as bioscientists and then got other degrees, like law degrees. Because another spinoff of biotechnology now is intellectual property. A lot of folks are making professions in that field, using both law expertise and bioscience expertise. We're trying to broaden the curriculum in the division, so that we're not just training students to be clones of their mentors, because it's clear that not all of our graduates are going to end up in academic institutions.
In fact I and the dean of the graduate school have put together a proposal, and we've started discussions with the business school for a combined bioscience Ph.D. and M.B.A., here at Emory, so that folks who want to go into biotech or the pharmaceutical industry have some business expertise and some actual formal business training, in addition to their bioscience Ph.D.'s.
And there really aren't any formal programs like that in this country.
We're not necessarily interested in expanding the numbers of people who we take into our training programs. At least not significant expansion, simply because of all the information that's out there about there being too many people in the postdoctoral pipeline, too many Ph.D.'s in the biosciences being turned out of academic institutions. The bottom line, however, is that, if you look at the data, unemployment among Ph.D. bioscientists is like 3%, which is not much different from national unemployment in all fields.
But then there's the counter-argument that there may be a lot of under-employment- in other words, how many of those folks are doing things that are not actually their ideal full-time job. So our philosophy, at least my philosophy is, and I know that at least some of the faculty share this with me, is that we should not necessarily do unwarranted expansion of the number of trainees who we train here. What we should do is try and attract the best and the most highly-qualified applicants who we can possibly attract to our programs, and give them the best possible training we can so that when they graduate, they will be competitive for whatever they wish to do.
I think that's a more reasonable kind of attitude, given the present climate. The medical school is, in the next five years, going to understand a rather major expansion in number of faculty. And I know that one of the things I'm going to face is lots of clamoring requests for expanding the number of students, because faculty like to have students in their laboratory. In the end, even though students are getting training and getting their dissertations out of what they are doing in those labs, they are almost exclusively working on projects that are working in the mentor's lab that are funded by outside sources.
So it's a mutually beneficial arrangement wherein the student, while in training, actually helps the mentor accomplish his or her research goals. And that's not inappropriate. We're very fortunate here that both of the deans in the graduate school and the school of medicine look at the contribution that they make to the supporting the division of biological and biomedical sciences, as being a basic underpinning of the research endeavor of their faculty, in addition to providing quality training for their graduate students.
So that's a nice situation, because it's beneficial to the faculty to have generous support from the institution. But I don't think that unbridled expansion is warranted. So that's going to be a controversial issue over the next five to ten years.
What do you say to those who argue that basic science needs to be accountable to the public in that it should have immediate applicability?
There has always been that argument out there that certain things that are done are so esoteric that they'll never be applicable to any sort of disease process, but if you look at it from the perspective of decades, there are many examples of things that were reported in the literature that you would have thought would never have had any sort of applicability at all, to any sort of disease process, yet over the years they turned out to be relevant to disease processes.
The whole mission field of molecular biology could be stated to fall into that category. People working with microbes, and looking at the ways they would replicate their DNA, and discovering reverse transcriptase and that sort of thing. Initially there was not a lot of indication of how those discoveries might eventually be relevant. And now, they gave birth to a whole plethora of very potent techniques and methodologies that allow us to do things that we never thought we would be able to do.
In my own field, I worked for twenty years in the field that I started working in as an undergraduate, doing basic, what I would call 'grind and find' biochemistry and separation techniques and protein analysis and enzyme assays, because those were the methodologies that were available. Now, with things like what I mentioned earlier, like putting cDNA's into these cells, I never would have envisioned that that would have even been possible ten years ago.
So I'm thinking about doing something that might be applicable to disease processes when originally what I was studying was basic cellular mechanisms, like 'how does the cell do this?' And that was a question about how does the cell manufacture protein hormones that are functional. I didn't initially set out to make those kinds of observations, but now the methodologies are there.
There are a lot of black boxes in biology yet- huge black boxes, even though, as you say, there are monumental amounts of new information. Yet in some areas scientists have only begun to tap the surface- look at the brain, for instance. We don't know how the brain works, but we're learning more. I don't think in my lifetime we'll have an understanding of how the brain works. So who's to say what's going to be useful and what's not.
It's kind of annoying, actually. In this very department there are investigators who are doing things that seem a little esoteric, and basically, when it comes time for them to apply for funding, because the reviewers in their ultimate god-like eminence, don't see the connection between basic-science research and any sort of disease process, they make it difficult for these folks to get funding. The argument can be made that the kinds of investigation they are engaged in could eventually be quite relevant. But because the stretch is a little bit long, and the funding situation is competitive, it's hard for these folks to keep their research going. And that's not right. Who is to say what's going to be important and what's not.
You can get basic science grants, but you have to justify it and you have to convince them that somewhere down the line this will have some kind of applicability.
Scientists have become much more vocal in trying to educate the layperson about the value of basic research. And some progress has been made. All the major scientific societies are engaged in lobbying Congress. And almost all of them have some kind of outreach program to get the word out to the lay-public about how it's important to do basic research.
Everybody was kind of hopeful a year ago when Congress actually made a commitment to double NIH funding over a five-year period. The first step in that direction was made during this fiscal year's budget, where congress increased NIH funding by 15%, and they also increased NSF funding. Then, for fiscal year 2,000, they're only upping it 4%, so it looks like it may not happen.
But at least there was headway made about the need for more research.
I think there's a lot of strong argument for supporting an overall increase in the availability of funding.
Also, we're training all these really smart folks to do research, and if they're not able to do it as a career, then we'll stop seeing reasonable numbers of high-quality applicants in the biosciences. That would be really bad- this country is known as the world leader in scientific research in many ways, and it would be a real shame if it went the other direction.
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