AIMS: The aim of this study was to evaluate the effect of PDX-1 (pancreatic and 
duodenal homeobox-1), NeuroD1 (neurogenic differentiation-1) and MafA (V-maf 
musculoaponeurotic fibrosarcoma oncogene homolog A) in the differentiation of 
induced pluripotent stem cells (iPSCs) into insulin-producing cells and to 
explore this new approach of cell transplantation therapy for type 1 diabetes in 
mice.
METHODS: iPSCs were infected with adenovirus (Ad-Mouse PDX-1-IRES-GFP, Ad-Mouse 
NeuroD1-IRES-GFP and Ad-Mouse Mafa-IRES-GFP) and then differentiated into 
insulin-producing cells in vitro. RT-PCR was applied to detect insulin gene 
expression, immunofluorescence to identify insulin protein, and mouse insulin 
enzyme-linked immunosorbent assay (ELISA) was used to evaluate the amount of 
insulin at different concentration of glucose. Insulin-producing cells were 
transplanted into the liver parenchyma of diabetic mice. Immunohistochemistry, 
intraperitoneal glucose tolerance test (IPGTT) and fasting blood glucose (FBG) 
were performed to assess the function of insulin-producing cells.
RESULTS: Insulin biosynthesis and secretion were induced in iPSCs and 
insulin-producing cells were responsive to glucose in a dose-dependent manner. 
Gene expression of the three-gene-modified embryoid bodies (EBs) was similar to 
the mouse pancreatic β cell line MIN6. Transplantation of insulin-producing 
cells into type I diabetic mice resulted in hyperglycemia reversal.
CONCLUSIONS: The insulin-producing cells we obtained from three-gene-modified 
EBs may be used as seed cells for tissue engineering and may represent a cell 
replacement strategy for the production of β cells for the treatment of type 1 
diabetes.