Two independent teams of researchers have taken a crucial step toward using human embryonic stem cells to treat nervous system disorders such as Huntington's disease or spinal cord injury. They have succeeded in coaxing human embryonic stem cells to differentiate into brain cell precursors that, when transplanted into mice brains, differentiate further into neurons and other types of brain cells.
Although all cells in the body contain the same set of genes, most cells are "differentiated"-that is, specialized for a particular function. For instance, a cell in the lens of the eye uses a different subset of genes than a bone cell or a brain cell. But a few cells, so-called stem cells, can differentiate into virtually any kind of cell, under the right conditions. However, the specific conditions needed to make a stem cell differentiate into a particular kind of cell are poorly understood.
Now, two papers published in December's Nature Biotechnology describe two slightly different approaches for inducing human embryonic stem cells to differentiate into precursors of brain cells. In both approaches, cells are grown on special surfaces and exposed to different types of signaling molecules, known as growth factors. After the stem cells had changed into brain cell precursors, the researchers transplanted them into the brains of newborn mice and showed that they further differentiated into various kinds of brain cells seen in normal brains. The ability to specifically control the development of embryonic stem cells into brain cells is an important step forward; however, further studies are needed to determine whether these brain cells are functional.
The Waisman Center
University of Wisconsin
1500 Highland Avenue
Madison, WI 53705
Benjamin E. Reubinoff
Department of Obstetrics and Gynecology
The Agnes Ginges Center for Human Neurogenetics
Hadassah University Hospital
(News & Views)
Laboratory of Stem Cell & Tumor Biology
Memorial Sloan-Kettering Cancer Center
New York, NY 10021
(C) Nature Biotechnology press release.
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