Bone marrow mesenchymal stem cells(BMSCs) have the ability of self-renewal and multi-directional differentiation.Recent reports showed that BMSCs could differentiate into endocrine cells of pancreas.However,the differentiation is not efficient enough to produce insulin-producing cells for the future therapeutic use.Pdx-1 is a crucial regulator for pancreatic development.Therefore we constructed a eukaryotic expression vector containing Pdx-1 to determine the effect of Pdx-1 ex-pression on differentiation of BMSCs in vitro.The results showed that BMSCs could self-assemble to form functional pancreatic islet-like structures after differentiation in vitro.The proportion of insu-lin-producing cells differentiated from Pdx-1+BMSCs was 28.23%±2.56%,higher than that from BMSCs transfected with vacant vector and Pdx-1-BMSCs(7.23%±1.56% and 4.08%±2.69% respec-tively) by flow cytometry.Immunocytochemical examination also testified the expression of multiple β-cells-specific genes such as insulin,glucagons,somatostatin in differentiated BMSCs.The results also revealed that the expressions of genes mentioned above in Pdx-1+BMSCs were higher than that in Pdx-1-BMSCs,which was confirmed by Western blotting analysis and RT-PCR.Glucose-induced insulin secretion from Pdx-1+BMSCs in 5mmol/L and 25mmol/L glocuse was(56.61±4.82) μU/mL and(115.29±2.56) μU/mL respectively,which were much higher than those from Pdx-1-BMSCs((25.53±6.49) μU/mL and(53.26±7.56) μU/mL respectively) .Grafted animals were able to maintain their body weight and survive for relatively longer periods of time than hyperglycemic sham-grafted controls,which demonstrated an overall beneficial effect of the grafted cells on the health of the animals.These findings thus suggested that exogenous expression of Pdx-1 should provide a promising approach for efficiently producing islet-like cells from BMSCs for the future therapeutic use in diabetic patients.
SUN Jiping1,YANG Yujia1,WANG Xiaoli1,SONG Jianhui1 & JIA Yanjie2 1.Department of Pediatrics,Xiang-Ya Hospital,Central-South University,Changsha 410008,China
