(W1082) Retinoic acid modulates self-renewal and differentiation of human pluripotent stem cells by regulating growth factors signaling and application
Abstract: Retinoic acid (RA) is the major metabolite from vitamin A (retinoid), and plays a central role in mammalian embryogenesis. In in vitro experiments, RA has been reported to be applied in different lineage cell differentiation and enhance the efficiency of reprogramming. The reported RA action in pluripotent stem cell is to interact with its nucleus Retinoic acid receptors (RARs) and alters the stem cell fate by directly interact with pluripotent gene OCT4 in transcriptional level. However, we believe that besides transcriptional level regulation, RA also modulates intracellular signaling that determine cell fate. But the actual molecular mechanisms in human pluripotent stem cell affected by RA is still remained unclear. In our study, we find several essential growth factors have been significantly changed in human embryonic stem cells (hESC) with RA treatment. When treated with RA, hESC shows a significant effect in TGFβ super family, fibroblast growth factor family and WNT signaling. More specifically, BMP4, NODAL and WNT3 are the most affected genes. With long-term RA treatment hESC will be gradually differentiated, we then suppress BMP4 and WNT3 signaling together with RA treatment and find out that hESC maintains its pluripotency and can further maintained over five generations. Moreover, when RA is supplied with differentiation chemicals like CHIR990321 and BMP4, RA strongly enhances their effect on growth factors like NODAL, BMP4 and WNT3. In current conclusion, we find an essential growth factor signaling network based on BMP4/WNT3 to explain how RA regulates hESC pluripotency and differentiation. Findings of RA effect on BMP4/WNT3 can be applied to different lineage differentiation and increase reprogramming and in vitro somite formation efficiency.
