RESUMEN

BACKGROUND:Transplantation of stem cell-derived islet β cells has been considered effective for the treatment of type 1 diabetes.Human umbilical cord mesenchymal stem cell is an ideal cellular source,but with a low differentiation efficiency to islet β cells. OBJECTIVE:To explore the possibility of human umbilical cord mesenchymal stem cells modified by MAFA and PDX1 to differentiate into insulin-producing cells. METHODS:MAFA-PDX1 lentivirus expression vectors were constructed.The efficiency and potentiality of human umbilical cord mesenchymal stem cells differentiated into insulin-producing cells with three methods were compared by cell morphology,RT-qPCR,and dithizone staining[protocol A:Simple lentivirus group;protocol B:Drug(nicotinamide β-mercaptoethanol)induction followed by lentivirus group;protocol C:lentivirus and drug induction group]. RESULTS AND CONCLUSION:(1)Morphological change of cells:Cell morphology was all altered after the induction of three protocols.At day 11,human umbilical cord mesenchymal stem cells induced by protocol B showed the most cell clusters among the three protocols,appearing aggregated islet-like cell clusters.(2)Islet-related gene expression detected by RT-qPCR:Horizontal comparison of the three protocols at the same induction time point showed that the expression levels of MAFA and PDX1 genes were the highest in protocol C on day 5 of induction,and those in protocol B were the highest on day 11 of induction.Human umbilical cord mesenchymal stem cells induced by protocol B had the greatest expression of GCG gene at day 5,INS and GLUT2 genes at day 11.(3)Dithizone staining to identify zinc ions:parts of the post-induced cells were stained brownish red by dithizone on day 11.The partial small island cells were stained brownish red with a darker color(positive expression)in protocol B.(4)It is concluded that the overexpression of MAFA and PDX1 can promote the differentiation of human umbilical cord mesenchymal stem cells into insulin-producing cells.The combination of MAFA-PDX1 gene modification and drug induction is superior to the single gene modification.