A comprehensive analysis of cytokine-induced and nuclear factor-κB-dependent genes in primary rat pancreatic β-cells

Type I diabetes mellitus results from an autoimmune destruction of pancreatic beta-cells. Cytokines, such as interleukin-1beta and interferon-gamma, are putative mediators of immune-induced beta-cell death and, under in vitro conditions, cause beta-cell apoptosis. We have recently shown that interleukin-1beta + interferon-gamma modifies the expression of >200 genes in beta-cells. Several of these genes are putative targets for the transcription factor nuclear factor-kappaB (NF-kappaB), and in subsequent experiments we showed that NF-kappaB activation is mostly pro-apoptotic in beta-cells. To identify cytokine-induced and NF-kappaB-regulated genes in primary rat beta-cells, we presently combined two experimental approaches: 1) blocking of NF-kappaB activation in cytokine-exposed beta-cells by a recombinant adenovirus (AdIkappaB((SA)2)) containing an inhibitor of NF-kappaB a(IkappaBac) super-repressor (S32A/S36A) and 2) study of gene expression by microarray analysis. We identified 66 cytokine-modified and NF-kappaB-regulated genes in beta-cells. Cytokine-induced NF-kappaB activation de. creased Pdx-1 and increased c-Myc expression. This, together with NF-kappaB-dependent inhibition of Glut-2, prohormone convertase-1, and lsl-1 expression, probably contributes to the loss of differentiated beta-cell functions. NF-kappaB also regulates several genes encoding for chemokines and cytokines in beta-cells. The present data suggest that NF-kappaB is a key "switch regulator" of transcription factors and gene networks controlling cytokine-induced beta-cell dysfunction and death.