The Role of Epigenetic Regulation and Pluripotency‐Related MicroRNAs in Differentiation of Pancreatic Stem Cells to Beta Cells

In this study, we aimed to research the effects of class‐I HDACs and glucose on differentiation of pancreatic islet derived mesenchymal stem cells (PI‐MSCs) to beta cells. Beta cell differentiation determined by flow cytometric analysis and gene expression levels of PDX1, PAX4, PAX6, NKX6.1, NGN3, INS2, and GLUT2. As a result the valproic acid, is an inhibitor of class‐I HDACs, caused the highest beta cell differentiation in PI‐MSCs. However, the cells in this group were at early stages of differentiation. Glucose co‐administration to this group carried the differentiation to higher levels, but these newly formed beta cells were not functional. Moreover, reduction in the levels of pluripotency factors that Oct3/4, c‐Myc, and Nanog were parallel to beta cell differentiation. Also, the levels of HDAC1 and acetylated H3/H4 were increased and methylated H3 was decreased by VPA treatment. In addition, we have detected over expression in genes of miR‐18a‐5p, miR‐19b‐5p, miR‐30d‐3p, miR‐124, miR‐146a‐5p, miR‐184, miR‐335, and miR‐433‐5p in parallel to beta cell differentiation. As the conclusion, this study is important for understanding the epigenetic mechanism that controls the beta cell differentation and it suggests new molecules that can be used for diagnosis, and treatment of diabetes. J. Cell. Biochem. 119: 455–467, 2018. © 2017 Wiley Periodicals, Inc.     

Effect of dual-specificity protein phosphatase 5 on pluripotency maintenance and differentiation of mouse embryonic stem cells

The MAPK/Erk signaling pathway is considered as a key regulator of the pluripotency and differentiation of embryonic stem (ES) cells, while dual-specificity protein phosphatases (DUSPs) are negative regulators of MAPK. Although DUSPs are potential embryogenesis regulators, their functions in the regulation of ES cell differentiation have not been demonstrated. The present study revealed that Dusp5 was expressed in mouse ES (mES) cells and that its expression was correlated with the undifferentiated state of these cells. Exogenous Dusp5 expression enhanced mES cell clonogenicity and suppressed mES cell differentiation by maintaining Nanog expression via the inhibition of the Erk pathway. Following Dusp5 knockdown, Nanog and Oct4 expression was significantly attenuated and the Erk signaling pathway was activated. Additionally, EBs derived from Dusp5 knockdown mES cells (KDEBs) exhibited a weak adherence capability, very little outgrowth, and a reduction in the number of epithelial-like cells. The expression of Gata6 (an endodermal marker) and Flk1 and Twist1 (mesodermal markers) was inhibited in KDEBs, which indicated that Dusp5 influenced the differentiation of these germ layers during EB development. Collectively, this study suggested that Dusp5 plays an important role in the maintenance of pluripotency in mES cells, and that Dusp5 may be required for EB development.