miR-196b-5p inhibits proliferation of Wharton's jelly umbilical cord stem cells.

Human umbilical cord mesenchymal stem cells can be obtained from different parts of the umbilical cord, including Wharton's jelly. Transplantation of Wharton's jelly umbilical cord stem cells (WJCMSCs) is a promising strategy for the treatment of various diseases. However, the molecular mechanisms underlying the proliferation of WJCMSCs are incompletely understood. Here, we report that overexpression of miR-196b-5p in WJCMSCs suppresses proliferation and arrests the cell cycle in G0/G1 phase, whereas knockdown of miR-196b-5p promotes WJCMSC proliferation and cell-cycle progression. Moreover, miR-196b-5p overexpression resulted in decreased levels of Cyclin A, Cyclin D, Cyclin E and cyclin-dependent kinases 2 and increased levels of p15INK4b , whereas miR-196b-5p knockdown had the opposite effects. In conclusion, our data suggests that miR-196b-5p inhibits WJCMSC proliferation by enhancing G0/G1-phase arrest.