Nobel Prize in Medicine awarded for cell "reprogramming"

The 2012 Nobel Prize in Physiology or Medicine has been awarded to Japanese scientist Shinya Yamanaka and British biologist John Gurdon for their work on stem cells and animal cloning, the Nobel Committee at the Karolinska Institute announced in Stockholm on Monday.

The medicine laureates’ announcement opened the week of Nobel revelations for 2012. The prize amount this year is 8 million Swedish kronor, roughly equivalent to $1.2 million.

Yamanaka and Gurdon have been named as leading candidates for the top international scientific award for several years in a row. Their work has created the foundation for obtaining new tissues and copies of entire organisms.

Shinya Yamanaka is a graduate of Kobe University, director of the Center for iPS Cell Research and Application at the Institute for Frontier Medical Sciences, Kyoto University, and a faculty member at the Gladstone Institute of Cardiovascular Disease in the US. Yamanaka heads the International Society for Stem Cell Research. He has received a number of prizes for his work, including the Shaw (2008) and Lasker (2009) prizes and the Finnish Millennium Technology Prize in summer 2012.

Sir John Gurdon is a graduate of Oxford University, a researcher at the Cancer Research and Embryology Institute at Cambridge University — which is named after him. Together with Yamanaka he received the 2009 Lasker Prize for his research.

What Yamanaka did

Stem cells are undifferentiated (immature) cells found in all multicellular organisms. They can develop into specialized cells that form various tissues and organs.

The term “stem cell” was introduced into science in 1909 by the Russian scientist Alexander Maximow — that is how he named blood cells that can give rise to several other cell types. In the 1960s blood cells were shown to form from bone marrow cells, and in 1981 American biologist Martin Evans isolated undifferentiated pluripotent stem cells (able to develop into different types of cells except embryonic cells) from a mouse embryo.

In 1998 the Americans John Gearhart and James Thomson first managed to derive and grow cultures of embryonic stem cells capable of developing into various mature cells and organs. In 1999 the journal Science recognized stem-cell research as the third-most-significant event in biology after the decoding of the DNA double helix and the Human Genome Project.

Using embryos to obtain stem cells raises ethical issues. For a long time it seemed impossible to avoid them because there was no way to turn back the “biological clock” and return specialized cells to their “youth.”

All the more sensational were the results from Yamanaka’s group, which developed a method for obtaining human stem cells from non-embryonic sources — iPS cells, induced pluripotent stem cells. Through genetic manipulation the researchers managed to “reprogram” cells that had already acquired a certain specialization.

According to many experts, if Yamanaka’s method can produce an unlimited supply of stem cells, this will allow the “growing” of needed tissues and will revolutionize transplantation medicine.

… And what Gurdon did

Cloning is the exact reproduction of a living organism in a number of copies. To produce a clone, nuclei from embryonic stem cells of an early embryo — ones that have not yet become very specialized — can be used. The nuclei are transplanted into egg cells from which their own nuclei have been removed; as these cells develop into new organisms, they can form a clone of genetically identical animals.

“Natural” cloning is widely known in humans as identical twins, which arise from the natural division of a fertilized egg into two independently developing embryonic cells.

In 1914, the German scientist Hans Spemann conducted the first experiments on transferring nuclei from one cell to another. In 1938 he suggested the possibility of transplanting a cell nucleus into an enucleated egg cell.

In the 1940s the Russian embryologist Georgy Lopashov developed a method for transferring cell nuclei into a frog egg. In June 1948 he submitted an article based on his experiments to the Journal of General Biology. Two months later came the infamous VASKhNIL session that marked the start of “Lysenkoism” — the persecution of advanced Russian biology schools. The typeset of Lopashov’s article was broken up and his work was forgotten.

Later, in the early 1960s, Gurdon refined Lopashov’s method. Removing the native nuclei from frog eggs, he transferred nuclei from various already-specialized cells into them. Eventually he began transferring nuclei from the cells of adult frogs, in particular from intestinal epithelium. Gurdon achieved the development of eggs with foreign nuclei up to fairly late stages, and in about two percent of cases the animals grew into adult frogs.

Source: RIA Novosti