The investigation of the effects of MYOD transactivator domain on beta cell formation

Insulin is a hormone secreted by the beta cells in the pancreas that allows glucose to enter the cells. Metabolic changes, which are caused by the lack of insulin, cause oxidative stress and diabetes. The main three genes used in beta cell programming experiments, Pdx1, Ngn3 and MafA, are important trancription factors for the acquisition of beta cell function and structure. MyoD is a major trancription factor responsible for skeletal myogenesis and has a strong transactivator domain that causes muscle cell formation. In this study, the effect of MyoD transactivator domain on transdifferentiation was investigated. MyoD transactivator domain (m3) is combined with Pdx1 (P), Ngn3 (N) and MafA (M) genes in different combinations using 2A peptide under a single promoter. (m3N)PM, (Nm3)PM, N(m3P)M, N(Pm3)M and NPM constructs were transferred to AR42J-B13 cells through adenoviruses. Insulin hormone production was observed in all cells, though adenovirus N(Pm3)M caused death in cells and cell structure deterioration. NPM construct stimulated 70% of the cells to produce insulin, while (m3N)PM construct stimulated 86% of the cells to produce insulin. It was demonstrated that MyoD transactivator domain causes a higher cell programming rate when MyoD TAD domain is linked to N-terminus of Ngn3 gene. The use of MyoD transactivator domain in addition to Pdx1, Ngn3 and MafA genes in beta cell programming allowed for more programmed cell types to be programmed at low rates.