Combined expression of transcription factors induces AR42J-B13 cells to differentiate into insulin-producing cells.

Neurogenin 3 (Ngn3) is a transcription factor that regulates an initial step of differentiation from uncommitted pancreatic progenitors into endocrine cells. Additional transcription factors are required for complete differentiation into mature pancreatic beta cells. In this study, we established an in vitro model system of beta-cell differentiation by adenovirus-mediated expression of several transcription factors in AR42J-B13 cells, a pancreatic progenitor-like cell line derived from exocrine pancreas. Exogenous expression of Ngn3 in AR42J-B13 cells induced expression of Nkx2.2, Pax4, and Pax6, which are all essential for beta-cell differentiation in mouse embryos. However, Ngn3 did not induce more downstream regulators of beta-cell differentiation, Nkx6.1 and Maf A. Coexpression of Nkx6.1 and Ngn3 induced endogenous expression of the insulin 2 gene, while coexpression of Maf A and Ngn3 induced both insulin 1 and 2 genes in AR42J-B13 cells. Our data demonstrated that Ngn3 expressed together with Nkx6.1 or MafA induces AR42J-B13 cells to differentiate into insulin-producing cells, supporting the use of these cells as a model system for studying beta-cell differentiation in vitro.