MicroRNA-induced pluripotent stem cells.

We read with much interest the recently published article, “Induced pluripotent stem cells in research and therapy,” by Teoh et al. The review described current methods of reprogramming and the potential of iPSC applications in medicine. This review encourages the exploration of reprogramming technology in Malaysia, and is helpful to both clinicians and stem cell researchers. We wish to share a few facts in the methods in reprogramming related to this interesting article. Since the discovery of the fi rst microRNA by Lee et al. in 1993 in C. elegans, over 1000 different human microRNAs have been identifi ed and these regulate most if not all biological and pathological processes. The mir-302 microRNA gene cluster is highly expressed and specifi c to embryonic stem cells and downregulated after differentiation. Recently, this cluster was used to reprogram somatic cells to iPSCs called microRNA-induced pluripotent cells (mirPS), with a remarkably high effi ciency of 10%. When mir-302 was co-expressed with the OSKM factors, it also enhanced their reprogramming effi ciency. (Table 1). Therefore microRNA manipulation is perhaps another valuable approach for the purpose of reprogramming.