Na-Xu-and-Thales-PapagiannakopoulosIn a new study scientists at UC Santa Barbara shed Light on Inner Workings of Human Embryonic Stem Cells. The findings is expected to help cancer research. The discovery is also expected to help with other diseases and injuries.

The study describes nature’s negative feedback loop in cell biology. Human embryonic stem cells are poised between a proliferative state with the potential to become any cell in the body and a differentiated state with a more limited ability to proliferate.

Scientists found that to maintain this delicate balance embryonic stem cells express a set of factors, including OCT4, SOX2, and KLF4, to control multiple genes that sustain the proliferative pluripotent state.

These genes can be repressed by a tiny RNA called miR-145, and in turn, one of the transcription factors, OCT4, can repress miR-145. Thus, a double negative feedback loop sets the delicate balance.

The new research actually shows that a microRNA , which is a single-stranded RNA whose function is to decrease gene expression  lowers the activity of three key ingredients in the recipe for embryonic stem cells. This microRNA is known as miR-145.

The discovery may have implications for improving the efficiency of methods designed to reprogram differentiated cells into embryonic stem cell-like cells.

The study is reported in the May 1 issue of the journal Cell.

The research team includes:

Senior author Kenneth S. Kosik, professor in the Department of Molecular, Cellular & Developmental Biology. Kosik is also co-director and Harriman Chair in Neuroscience Research of UCSB’s Neuroscience Research Institute.

James Thomson, who provided an important proof to the research effort. Thomson, an adjunct professor at UCSB, is considered the “father of stem cell biology.” Thomson pioneered work in the isolation and culture of non-human primate and human embryonic stem cells.

First author Na Xu, a postdoctoral fellow who is also supported by the California Institute for Regenerative Medicine (CIRM).

Thales Papagiannakopoulos, a graduate student working in the Kosik lab, was very generous in helping Na Xu with  the experiments.

Original source: University Or California, Santa Barbara [www.ia.ucsb.edu/pa/display.aspx?pkey=1999#description]