TY - JOUR

T1 - Cytokine-induced proapoptotic gene expression in insulin-producing cells is related to rapid, sustained, and nonoscillatory nuclear factor-kappaB activation.

AU - Ortis, Fernanda

AU - Cardozo, Alessandra K

AU - Crispim, Daisy

AU - Störling, Joachim

AU - Mandrup-Poulsen, Thomas

AU - Eizirik, Décio L

N1 - Keywords: Animals; Apoptosis; Cells, Cultured; Cytokines; Extracellular Signal-Regulated MAP Kinases; Gene Expression Profiling; Gene Expression Regulation; I-kappa B Proteins; Insulin; Insulin-Secreting Cells; Kinetics; NF-kappa B; Nitric Oxide Synthase Type II; Promoter Regions (Genetics); Protein Denaturation; Protein Isoforms; Rats; Response Elements; Time Factors

PY - 2006

Y1 - 2006

N2 - Cytokines, such as IL-1beta and TNF-alpha, contribute to pancreatic beta-cell death in type 1 diabetes mellitus. The transcription factor nuclear factor-kappaB (NF-kappaB) mediates cytokine-induced beta-cell apoptosis. Paradoxically, NF-kappaB has mostly antiapoptotic effects in other cell types. The cellular actions of NF-kappaB depend on the cell type, the nature and duration of the stimulus, the periodicity, and the degree of activity of the particular dimers involved. To clarify the reasons behind the proapoptotic effects of NF-kappaB in pancreatic beta-cells, we compared the pattern of cytokine-induced NF-kappaB activation between rat insulin-producing cells (INS-1E cells) and fibroblasts (208F cells). NF-kappaB activation was induced in INS-1E cells and in 208F cells after exposure to cytokines, but apoptosis was induced only in INS-1E cells, with a more pronounced proapoptotic effect of IL-1beta than of TNF-alpha. NF-kappaB activation in IL-1beta-exposed INS-1E cells was earlier and more marked as compared with TNF-alpha-exposed INS-1E cells or IL-1beta-exposed 208F cells. Both cytokines induced a prolonged (up to 48 h) and stable NF-kappaB activation in INS-1E cells, whereas IL-1beta induced an oscillatory NF-kappaB activation in 208F cells. p65/p65 and p65/p50 were the predominant NF-kappaB dimers in IL-1beta-exposed INS-1E cells and 208F cells, respectively. IL-1beta induced a differential usage of cis-elements in the inducible nitric oxide synthase promoter region in the two cell-lines and an increase in ERK1/2 activity in INS-1E cells but not in 208F cells. Cytokine-induced expression of IkappaB isoforms and other NF-kappaB target genes (Fas, MCP-1, and inducible nitric oxide synthase) was severalfold higher in INS-1E cells than in 208F cells. These results suggest that cytokine-induced NF-kappaB activation in insulin-producing cells is more rapid, marked, and sustained than in fibroblasts, which correlates with a more pronounced activation of downstream genes and a proapoptotic outcome.

AB - Cytokines, such as IL-1beta and TNF-alpha, contribute to pancreatic beta-cell death in type 1 diabetes mellitus. The transcription factor nuclear factor-kappaB (NF-kappaB) mediates cytokine-induced beta-cell apoptosis. Paradoxically, NF-kappaB has mostly antiapoptotic effects in other cell types. The cellular actions of NF-kappaB depend on the cell type, the nature and duration of the stimulus, the periodicity, and the degree of activity of the particular dimers involved. To clarify the reasons behind the proapoptotic effects of NF-kappaB in pancreatic beta-cells, we compared the pattern of cytokine-induced NF-kappaB activation between rat insulin-producing cells (INS-1E cells) and fibroblasts (208F cells). NF-kappaB activation was induced in INS-1E cells and in 208F cells after exposure to cytokines, but apoptosis was induced only in INS-1E cells, with a more pronounced proapoptotic effect of IL-1beta than of TNF-alpha. NF-kappaB activation in IL-1beta-exposed INS-1E cells was earlier and more marked as compared with TNF-alpha-exposed INS-1E cells or IL-1beta-exposed 208F cells. Both cytokines induced a prolonged (up to 48 h) and stable NF-kappaB activation in INS-1E cells, whereas IL-1beta induced an oscillatory NF-kappaB activation in 208F cells. p65/p65 and p65/p50 were the predominant NF-kappaB dimers in IL-1beta-exposed INS-1E cells and 208F cells, respectively. IL-1beta induced a differential usage of cis-elements in the inducible nitric oxide synthase promoter region in the two cell-lines and an increase in ERK1/2 activity in INS-1E cells but not in 208F cells. Cytokine-induced expression of IkappaB isoforms and other NF-kappaB target genes (Fas, MCP-1, and inducible nitric oxide synthase) was severalfold higher in INS-1E cells than in 208F cells. These results suggest that cytokine-induced NF-kappaB activation in insulin-producing cells is more rapid, marked, and sustained than in fibroblasts, which correlates with a more pronounced activation of downstream genes and a proapoptotic outcome.

U2 - 10.1210/me.2005-0268

DO - 10.1210/me.2005-0268

M3 - Journal article

C2 - 16556731

VL - 20

SP - 1867

EP - 1879

JO - Molecular Endocrinology

JF - Molecular Endocrinology

SN - 0888-8809

IS - 8

ER -