The Nobel Prize in Physiology/Medicine 2012 was awarded jointly to two pioneers of stem cell research -- Briton John B. Gurdon and Japan's Shinya Yamanaka -- for the discovery that mature, specialized cells can be reprogrammed to become immature cells capable of developing into all tissues of the body.
"Their findings have revolutionized our understanding of how cells and organisms develop," the Nobel Assembly at Karolinska Institute said in a press release announcing the award.
Gurdon discovered in 1962 that the specialization of cells is reversible. In a classic experiment, he replaced the immature cell nucleus in an egg cell of a frog with the nucleus from a mature intestinal cell. This modified egg cell developed into a normal tadpole. The DNA of the mature cell still had all the information needed to develop all cells in the frog.
His landmark discovery was initially met with skepticism but became accepted when it had been confirmed by other scientists. It initiated intense research and the technique was further developed, leading eventually to the cloning of mammals.
Yamanaka discovered more than 40 years later how intact mature cells in mice could be reprogrammed to become immature stem cells. Surprisingly, by introducing only a few genes, he could reprogram mature cells to become pluripotent stem cells, i.e. immature cells that are able to develop into all types of cells in the body. The discovery was published in 2006 and was immediately considered a major breakthrough.
"These groundbreaking discoveries have completely changed our view of the development and cellular specialization. We now understand that the mature cell does not have to be confined forever to its specialized state. Textbooks have been rewritten and new research fields have been established. By reprogramming human cells, scientists have created new opportunities to study diseases and develop methods for diagnosis and therapy," says the press release.
Research during recent years has shown that pluripotent stem cells, or iPS cells, can give rise to all the different cell types of the body. These discoveries have also provided new tools for scientists around the world and led to remarkable progress in many areas of medicine. iPS cells can also be prepared from human cells.
For instance, skin cells can be obtained from patients with various diseases, reprogrammed, and examined in the laboratory to determine how they differ from cells of healthy individuals. Such cells constitute invaluable tools for understanding disease mechanisms and so provide new opportunities to develop medical therapies.
The iPS cells are believed to have great potential for regenerative medicine.
Gurdon (79) received his Doctorate from the University of Oxford in 1960 and was a post-doctoral fellow at California Institute of Technology. He joined Cambridge University, UK, in 1972 and has served as Professor of Cell Biology and Master of Magdalene College. He is currently at the Gurdon Institute in Cambridge.
Yamanaka (50) obtained his MD in 1987 at Kobe University and trained as an orthopedic surgeon before switching to basic research. He received his PhD at Osaka University in 1993, after which he worked at the Gladstone Institutes in San Francisco and the Nara Institute of Science and Technology in Japan. Yamanaka is currently a Professor at Kyoto University and also serves as senior investigator at the Gladstone Institutes.
For comments and feedback: editorial@rttnews.com