Nitric oxide stimulates insulin gene transcription in pancreatic beta-cells

Abstract

Recent studies have identified a positive role for nitric oxide (NO) in the regulation of pancreatic beta-cell function. The aim of this study was to determine the effects of short-term exposure to NO on beta-cell gene expression and the activity of the transcription factor PDX-1. NO stimulated the activity of the insulin gene promoter in Min6 beta-cells and endogenous insulin mRNA levels in both Min6 and isolated islets of Langerhans. Addition of wortmannin prior to NO stimulation blocked the observed increases in insulin gene promoter activity. Although NO addition stimulated the phosphorylation of p38, inhibition by SB203580 did not block the effect of NO on the insulin gene promoter. NO addition also stimulated both the nuclear accumulation and the DNA binding activity of PDX-1. This study has shown that over 24h, NO stimulates insulin gene expression, PI-3-kinase activity and the activity of the critical beta-cell transcription factor PDX-1.