123. rAAV-pdx-1 Augmented the Insulin-Producing Cells

Abstract

Inducing liver cells to trans-differentiate into endocrine b cell has been a potential strategy for the better treatment of type 1diabetes. Pancreatic and duodenal homeobox gene 1(pdx-1) has been documented increasingly as a crucial transcription factor in pancreatic islet development and differentiation. This study was conducted to evaluate whether pdx-1 delivered by adeno-associated virus (AAV) could induce liver cells to differentiate into insulin-producing cells and to explore the origin of these cells. Here we used 4|[prime]|10e11 AAV to deliver pdx-1to STZ-induced diabetic rats via the portal vein. Immunofluoroscent staining showed the presence of insulin-positive cells in AAV diabetic control rat livers, which occurred as single cells only, While AAV-pdx-1 group showed more insulin-positive cells, occurring as small clusters as well as single cells. These insulin-positive cells are also positive for hepatic oval stem cell markers, ck19 and Thy-1. Except for the gene expression of pdx-1, insulin1 and insulin 2, RT-PCR and quantitative real-time PCR also detected significantly higher level of other important transcription factors, NeuroD, Neurogenin 3(Ngn3) in AAV-pdx-1 treated diabetic rat livers. And AAV-pdx-1 treated diabetic rats showed partially ameliorated hyperglycemia, better gain of body weight and improved lipid levels. Our data indicated that hyperglycemia per se could induce rat hepatic oval stem cells into insulin-producing cells in vivo and that pdx-1 enhanced this developmental shift by promoting the expression of some transcription factors necessary for beta cell development and function, thereby producing more biologically active insulin in the livers of diabetic rats and ameliorating hyperglycemia and severe dyslipidemia.