autophagy involves in differentiation of insulin-secreting cells from adipose derived stem cells

Objective: destruction of pancreatic beta-cells induces an insulin deficiency and causes type 1 diabetes. the role of autophagy in inducing insulin-secreting cells (iscs) from adipose-derived mesenchymal stem cells (amscs) was investigated in the current study. materials and methods: in this experimental study, the isolated amscs were characterization and exposed to a cocktail differentiation medium (cdm) in the absence or presence of 3-methyladenine (3ma), an autophagy inhibitor. the differentiation of iscs was confirmed by the evaluation of the expression of beta-cell-specific genes including pancreatic and duodenal homeobox 1 (pdx1), musculoaponeurotic fibrosarcoma oncogene homolog a (maf-a), nk class of homeodomain-encoding genes 6.1 and 2.2 (nkx6-1 and nkx2.2), glucose transporter 2 (glut-2) and inslin. using newport green (ng), insulin-positive cells were identified. insulin secretion in response to various glucose concentrations was measured. autophagy was evaluated by acridine orange (ao) staining. also, expression of autophagy-associated genes, including autophagy-related gene 5 (atg-5), autophagy-related gene 7 (atg-7), beclin-1, and mammalian target of rapamycin (mtor), was evaluated by real-time polymerase chain reaction (pcr) method. results: we observed a significant increase of beta-cell specific genes expression in the cdm-treated cells (p<0.01 or p<0.001), whereas the expression of these genes was down-regulated in 3ma-exposed cells. expression of insulin and glut-2 genes (p<0.01 and p<0.05, respectively), insulin secretion in response to glucose (p<0.01), and percentage of ng-positive cells (p<0.05) in the 3ma-exposed cells were considerably lower than the cells treated with cdm. the percentage of ao-positive cells (p<0.01) and the expression of autophagy-related genes (p<0.001) was significantly enhanced in the cdm group. these events were significantly prevented by the 3ma. conclusion: our data showed that autophagy is necessary for beta-cell differentiation, and preventing autophagy by 3ma causes the reduction of beta-cell differentiation and insulin secretion.