Generation of a Novel Gene Therapy Vector Encoding Beta-Cell–Specific Insulin for Diabetes Treatment

Insulin injection is the main treatment modality especially for patients with type 1 diabetes. Despite the development of several insulin analogs, recent meta-analysis indicated that rapid and long acting insulin analogs provide little benefit compared to conventional insulins regarding to glycemic control. Therefore, gene therapy methods are investigated to develop a novel treatment approach to reconstitute a natural endogenous insulin expression profile in diabetic patients. For this purpose, Multisite Gateway Technology was employed to generate a transfer vector carrying lentiviral backbone with minimal insulin promotor hooked up to proinsulin gene sequence. Following confirmation of the transfer plasmid by restriction enzyme digestion and DNA sequence analysis, high-titer LentiINS vectors at a concentration of 10e9 TU/ml were successfully produced by CaPO4 cotransfection of 293T cells with packaging and transfer plasmids. While transduction of NIT1 mouse pancreatic beta cell lines produced 3 fold increase in insulin gene expression compared to controls, no insulin expression was detected in 293T kidney cell line. These results indicate that we successfully constructed an HIV-based lentiviral gene therapy vector being capable of beta cell-specific insulin gene expression and secretion (TUBITAK 215S820).