Mouse ES cells over-expressing the transcription factor NeuroD1 show increased differentiation towards endocrine lineages and insulin-expressing cells.

Embryonic stem (ES) cells which constitutively express the Pdx-1, Ngn-3, NeuroD1, Nkx2.2, and Nkx6.1 transcription factors were engineered by means of lentiviral vectors, following a multi-step infection procedure to successively generate ES cell lines expressing one, two, and three factors, respectively. Each ES cell line was allowed to differentiate into nestin+/Isl-1+ endocrine precursors, then into more mature pancreatic cells, and subsequently analysed for expression of Glc, Ins, and Sst, markers of alpha, beta and delta cells, respectively. Each ES cell line generated displayed a unique pattern of gene expression. The ES cell line expressing NeuroD1 displayed vastly elevated levels of Glc, Ins-1, Ins-2 and Sst, and showed an increase in Pdx-1, Pax-4, Nkx6.1, Isl-1, Glut-2 and GK transcript levels. Furthermore, immunofluorescence analysis revealed that differentiation of NeuroD1-expressing ES cells in nestin+/Isl-1+ multilineage progenitors, followed by the formation of C-peptide+/insulin+ clusters, was accelerated. Together, these results indicate that stable expression of NeuroD1 in ES cells facilitates differentiation into endocrine and insulin-producing cells.