beta-cell apoptosis - Stimuli and signaling

Pancreatic beta -cells are sensitive to a number of proapoptotic stimuli. T hus, apoptosis is an important part of the physiological neonatal remodelin g of the endocrine pancreas, and a number of pathological stimuli involved in type 1 and type 2 diabetes have been shown to elicit beta -cell apoptosi s. Factors of relevance to type 1 diabetes include proinflammatory cytokine s, nitric oxide, and reactive oxygen species as well as Fas ligand. Recent findings that free fatty acids, glucose, sulfonylurea, and amylin cause bet a -cell apoptosis in vitro suggest that programmed cell death may also be i nvolved in the pathogenesis of type 2 diabetes. Furthermore, there is evide nce favoring a convergence in signaling pathways toward common effecters of beta -cell apoptosis elicited by stimuli implicated in the pathogenesis of type 1 and type 2 diabetes. Therefore, recent studies involving the stimul i and signaling pathways of beta -cell apoptosis-in particular, mitogen- an d stress-activated protein kinases-will be reviewed. It is concluded that i mmunological, inflammatory, and metabolic signals cause beta -cell apoptosi s, and the possibility that these signals converge toward a common beta -ce ll death signaling pathway should be investigated further.