Despite their celebrated “immortality,” the capacity of embryonic stem (ES) cells for endless division has its limits. After a very extended childhood spent dividing in a culture dish, even stem cells tend to grow up and assume adult roles as workaday nerve, muscle, or blood cells, never to return to their youthful state.

How some ES cells succeed in recapturing lost cellular innocence and start anew once they begin maturing is described in a forthcoming study in Proceedings of the National Academy of Sciences, authored by a team of scientists from the Salk Institute for Biological Studies.

According to professor Juan Carlos Ispizúa Belmonte, Ph.D., of the Gene Expression Laboratory, embryonic stem cells represent enormous hope for treating otherwise incurable diseases, but before they could design therapeutic strategies or introduce these cells into patients, they have to learn how to differentiate them into specific cell types and how to tame their formidable proliferating ability.

In a study published earlier this year, the same Belmonte and Gage lab team demonstrated that a few ES cells in a culture dish tended to lose stemness and evolve into muscle cell precursors, most likely goaded by a muscle differentiation factor known as BMP. But when those maturing cells were forced to produce Nanog, they reverted to their naïve state and regained pluripotency.

Atsushi Suzuki, PhD., a former postdoctoral fellow in the Belmonte lab, was the lead author of both that and the present study. “It was exciting because nobody knew that ‘reverse differentiation’ occurred in ES cell cultures,” he said referring to the first report. “And nobody knew how Nanog maintains an undifferentiated ES cell population.”

Source: Science Daily