[Role of INGAP-pp in the differentiation of hUCMSCs into insulin producing cells]

To find out a protocol for the efficient and directional differentiation from human umbilical cord mesenchymal stem cells (hUCMSCs) into insulin-producing cells (IPCs).

HUCMSCs were induced to differentiate into IPCs by an improved protocol based on a traditional protocol with addition of islet neogenesis-associated protein-pp (INGAP-pp), and the IPCs were identified by morphological observation, flow cytometry, real-time quantitative PCR, immunofluorescence and ELISA.

Compared with the traditional protocol, the improved protocol resulted in the higher rate of C peptide positive cells (P<0.05) and the increased mRNA expressions of pancreas development related transcription factor PDX-1, Ngn3, NeuroD1, MafA, insulin, Glut-2 (P<0.05). Meanwhile, by the improved protocol the protein expressions of C peptide, PDX-1 and Nkx6.1 were positive, and insulin and C-peptide release were promoted (P<0.05) as demonstrated by glucose challenge test.

INGAP-pp may facilitate the differentiation of hUCMSCs into IPCs. However, the IPCs are not as mature as normal human islet β cells.