Identification of novel cytokine-induced genes in pancreatic β-cells by high-density oligonucleotide arrays

Abstract

Type 1 diabetes is an autoimmune disease resulting from the selective destruction of insulin-producing β-cells. Cytokines may contribute to pancreatic β-cell death in type 1 diabetes. β-cell exposure to interleukin (IL)-1β induces functional impairment, whereas β-cell culture for 6-9 days in the presence of IL-1β and interferon (INF)-γ leads to apoptosis. To clarify the mechanisms involved in these effects of cytokines, we studied the general pattern of cytokine-induced gene expression in β-cells. Primary rat β-cells were fluorescence-activated cell sorter-purified and exposed for 6 or 24 h to control condition, IL-1β + INF-γ or IL-1β alone (24 h only). Gene expression profile was analyzed in duplicate by oligonucleotide arrays. Nearly 3,000 transcripts were detected in controls and cytokine-treated β-cells. Of these, 96 and 147 displayed changes in expression after 6 and 24 h, respectively, of exposure to IL-1β + INF-γ whereas 105 transcripts were modified after a 24-h exposure to IL-1β. The cytokine-responsive genes were clustered according to their biological functions. The major clusters observed were metabolism, signal transduction, transcription factors, protein synthesis/ processing, hormones, and related receptors. These modifications in gene expression may explain some of the cytokine effects in β-cells, such as decreased protein biosynthesis and insulin release. In addition, there was induction of diverse cytokines and chemokines; this suggests that β-cells may contribute to mononuclear cell homing during insulitis. Several of the cytokine-induced genes are potentially regulated by the transcription factor NF-κB. Clarification of the function of the identified cytokine-induced gene patterns may unveil some of the mechanisms involved in β-cell damage and repair in type 1 diabetes.