Proteome analysis of interleukin-1 beta-induced changes in protein expression in rat islets of Langerhans

The intracellular molecular events involved in the P-cell death process are complex but poorly understood. Cytokines, e.g., interleukin (IL)-1 beta, m ay play a crucial role in inducing this process. Protein synthesis is neces sary for the deleterious effect of IL-1, and induction of both protective a nd deleterious proteins has been described. To characterize the rather comp lex pattern of islet protein expression in rat islets in response to IL-1, me have attempted to identify proteins of altered expression level after IL -1 exposure by 2D gel electrophoresis and mass spectrometry. Of 105 signifi cantly changed (i.e., up- or downregulated or de novo-induced) protein spot s, we obtained positive protein identification for 60 protein spots. The 60 identifications corresponded to 57 different: proteins. Of these, 10 prote ins were present in two to four spots, suggesting that posttranslatory modi fications had occurred. In addition, 11 spots contained more than one prote in. The proteins could be classified according to their function into the f ollowing groups: 1) energy transduction; 2) glycolytic pathway; 3) protein synthesis, chaperones, and protein folding; and 4) signal transduction, reg ulation, differentiation, and apoptosis. In conclusion, valuable informatio n about the molecular mechanisms involved in cytokine-mediated beta -cell d estruction was obtained by this approach.