JUDY WOODRUFF: Next, to the 2012 Nobel Prizes. The first was awarded today for groundbreaking work in reprogramming cells in the body.
Ray Suarez looks at those achievements.
MAN: The Nobel Assembly at Karolinska Institute has today decided to award the Nobel Prize in Physiology or Medicine,2012 jointly to John B. Gurdon and Shinya Yamanaka.
RAY SUAREZ: The two scientists are from two different generations and celebrated today’s announcement half-a-world apart.
But today they were celebrated together for their research that led to a groundbreaking understanding of how cells work.
Sir John Gurdon of CambridgeUniversity was awarded for his work in 1962. He was able to use specialized cells of frogs, like skin or intestinal cells, to generate new tadpoles and show DNA could drive the formation of all cells in the body.
Forty years later, Dr. Yamanaka built on that and went further. He was able to turn mature cells back into their earliest form as primitive cells. Those cells are in many ways the equivalent of embryonic stem cells, because they have the potential to develop into specialized cells for heart, liver and other organs.
Dr. Shinya Yamanaka is currently working at KyotoUniversity. Embryonic stem cells have had to be harvested from human embryos, a source of debate and considerable controversy.
For Gurdon, the prize had special meaning. At a news conference in London, he recalled one schoolteacher’s reaction to his desire to study science.
JOHN GURDON, co-winner, Nobel Prize For Medicine or Physiology: It was a completely ridiculous idea because there was no hope whatever of my doing science, and any time spent on it would be a total waste of time, both on my part and the part of the person having to teach him. So that terminated my completely — completely terminated my science at school.
RAY SUAREZ: The men will receive their award in Stockholm in December.
For some detail on the science and the men behind today’s prize, I’m joined by Dr. David Scadden. He’s co-director of the Harvard Stem Cell Institute and a professor at HarvardMedicalSchool. He also knows both of today’s laureates.
Dr. Scadden, a previous winner said of Gurdon’s work, it’s changed the way we understand how cells in the body become specialized.
What was the scientific consensus before that? What had we concluded about the way stem cells worked, or the way the cells work?
DR. DAVID SCADDEN, Harvard Stem Cell Institute: Sure.
Well, I think cells were viewed much the same way we view our own lives, that there’s a trajectory where we go from a person of great potential but of unclear specialty, become more and more differentiated as time goes on, making particular choices.
And it was thought that stem cells had the same kind of pathway, if you will, that as cells started out, they could become any cell of the body, but gradually they became progressively more specialized.
And it was thought that was basically a one way street, that if you were a skin cell, you would always be a skin cell and you could never become anything else.
What Gurdon showed and then subsequently Yamanaka showed is that that’s not the case. It’s not just in one direction, that there actually is the ability to reverse course and go all the way back to becoming the most primitive of cells, even if you start with something that is as mature as one of the cells from any one of us.
RAY SUAREZ: Often, co-winners are not collaborators. In this case, the discoveries are more than 40 years apart.
DR. DAVID SCADDEN: Yes.
RAY SUAREZ: How do they relate to each other?
DR. DAVID SCADDEN: Yes. It’s very interesting.
Actually, Yamanaka was born the year that Sir John Gurdon’s work was published. So, they’re very different in generation, as well as in area of emphasis. So, Sir John Gurdon was working on a topic that was very much of concern at the time of the late ’50s and early 1960s.
DNA had just been discovered. It had been recognized as being the stuff that was the code of life and of what cells could become. But it wasn’t clear if DNA was stable. So, as the cell became more specialized, did its genes change? Did they become different than they were in the earliest stage of, say, the fertilized egg?
And so what Gurdon did was, he asked the question, by moving the DNA that’s in a nucleus from a mature cell into the cytoplasm of an egg, and he showed that that nucleus could actually go back, could be reprogrammed so that it could become a — just like a fertilized egg, it could become any cell type.
That meant that cells really had this plasticity. It was a topic though that frankly was considered a little bit of at the margin, if you will, an interesting observation, but of unclear practical significance.
It really picked up steam decades later as it became possible to think about ways to use pluripotent or so-called embryonic stem cells.
And people started thinking about, well, what if we had another source of those kinds of cells, those cells that are really the fundamental cells that can become anything in the body?
And it was Yamanaka who came up with the bold experiment that said, indeed, you can do this. You can do this in a very practical straightforward way that actually makes it possible for essentially any laboratory to now be able to do that, to create these cells that are equivalent to the embryonic stem cells in most practical ways.
RAY SUAREZ: In the middle of these two men’s world was Dolly the sheep. And Sir Ian Wilmut wasn’t recognized for his work. Is that an oversight?
DR. DAVID SCADDEN: Well, it’s hard to say.
I think that Sir John Gurdon had demonstrated the principle that if you transfer the nucleus where DNA is contained and put it into an egg, that it could revert all the way back to become essentially capable of forming a new organism.
What Sir Ian did was that he demonstrated you could do that with something as complex as a sheep.
And that was really a very substantial breakthrough. It was something that really brought it startling into focus for I think the lay public and scientists that this was something that could be more than just an odd experiment in a laboratory and something that might have more practical implications.
But the transition of that concept to a practical way in which you could do it in any cell was something that was really a very substantial leap. And Yamanaka gets credit for being the — really the courageous and insightful scientist that he was.
RAY SUAREZ: So, by creating these techniques, has Yamanaka’s work opened the door to things we couldn’t even have imagined years ago?
DR. DAVID SCADDEN: I think so.
You know, the idea of being able to clone an animal, which certainly Ian Wilmut’s work has shown and was originally pioneered by John Gurdon, is something that was of great interest mostly for biologists, perhaps even in the agricultural world, but wasn’t something that really could have practical implications for medicine.
What Yamanaka has shown is that you could take a cell from any one of us, which would include people who have diseases for which we otherwise have very few tools to study them, and create a cell that could now become essentially the toolkit from which we could look at the cells that are affected in the disease.
So, if I may give you an example, if we think about people who have a devastating neurologic disease, like Lou Gehrig’s disease, ALS, we haven’t been able to study the neurons that are affected by that disease.
Now we can take a skin sample from one of those individuals. You can do this reprogramming process that Yamanaka taught us how to do.
It can become a stem cell that can then be transformed into or made into a nervous cell, a nervous system cell, a cell of the brain, that’s affected by this disease ALS.
And suddenly we have abundant cells in the laboratory that now are the — really the bona fide models of a disease where previously we had few tools.
So, that is a dramatic step forward that possibly opens up the door for new kinds of therapies.
RAY SUAREZ: Dr. Scadden, thanks a lot.
DR. DAVID SCADDEN: Thank you.
RAY SUAREZ: And, online, you can watch an interview with Shinya Yamanaka in which the Nobel Prize winner talks about his research using stem cell-derived nerve cells to treat animals with spinal cord injuries.