Scientists convert skin cells to stem cells more effieciently

WASHINGTON - A team at Sanford-Burnham Medical Research Institute (Sanford-Burnham) have identified several specific microRNAs (miRNAs) that are important during reprogramming and exploited them to make the transition from skin cell to induced pluripotent stem (iPS) cell more efficient.

“We identified several molecular barriers early in the reprogramming process and figured out how to remove them using miRNA,” said Tariq Rana, director of the RNA Biology program at Sanford-Burnham and senior author of the study.

“This is significant because it will enhance our ability to use iPS cells to model diseases in the laboratory and search for new therapies.”

MiRNAs are small strands of genetic material that may play a major role in many diseases by gumming up protein production. In this study, Rana and his colleagues observed that three groups of miRNAs, including two known individually as miR-93 and miR-106b, are activated as part of a defense mechanism that occurs when cells are stressed by the standard skin cell reprogramming process.

Digging deeper, they determined that miR-93 and miR-106b target two proteins called Tgfbr2 and p21, which slow up the path to iPS cells by halting the cell cycle - the cell’s process of duplicating its DNA and dividing into two identical “daughter” cells - and promoting cell death.

Not only does this finding reveal more about the genetic underpinnings of iPS cell formation, but the researchers took advantage of this new information to speed up the process. When they added extra miR-93 and miR-106b to skin cells, Tgfbr2 and p21 were blocked, more cells survived, and iPS cells were more readily obtained.

The study has been published in the EMBO Journal. (ANI)