10/07/2011 PERMALINK
By adding just 3 genes to a mature liver cells, scientist turn them into a functional neurons. Fully mature liver cells from laboratory mice have been transformed directly into functional neurons by researchers at the Stanford University School of Medicine. The switch was accomplished with the introduction of just three genes and did not require the cells to first enter a pluripotent state. It is the first time that cells have been shown to leapfrog from one fundamentally different tissue type to another. The accomplishment extends previous research by the same group, which showed in 2009 that it is possible to directly transform mouse fibroblasts, or skin cells, into neurons. “These liver cells unambiguously cross tissue-type boundaries to become fully functional neural cells,” said Marius Wernig, MD, PhD assistant professor of pathology and a member of Stanford’s Institute for Stem Cell Biology and Regenerative Medicine. “Even more surprising, these cells also simultaneously silence their liver-gene expression profile. They are not hybrids; they are completely switching their identities.” The cells make the change without first becoming a pluripotent type of stem cell — a step long thought to be required for cells to acquire new identities.