Double-stranded RNA cooperates with interferon-gamma and IL-1 beta to induce both chemokine expression and nuclear factor-kappa B-dependent apoptosis in pancreatic beta-cells: potential mechanisms for viral-induced insulitis and beta-cell death in type 1 diabetes mellitus.
Viral infections may trigger the autoimmune assault leading to type 1 diabetes mellitus. Double-stranded RNA (dsRNA) is produced by many viruses during their replicative cycle. The dsRNA, tested as synthetic poly(IC) (PIC), in synergism with the proinflammatory cytokines interferon-gamma (IFN-gamma) and/or IL-1 beta, results in nitric oxide production, Fas expression, beta-cell dysfunction, and death. Activation of the transcription nuclear factor-kappa B (NF-kappa B) is required for PIC-induced inducible nitric oxide synthase expression in beta-cells, and we hypothesized that this transcription factor may also participate in PIC-induced Fas expression and beta-cell apoptosis. This hypothesis, and the possibility that PIC induces expression of additional chemokines and cytokines (previously reported as NF-kappa B dependent) in pancreatic beta-cells, was investigated in the present study. We observed that the PIC-responsive region in the Fas promoter is located between nucleotides -223 and -54. Site-directed mutations at the NF-kappa B and CCAAT/enhancer binding protein-binding sites prevented PIC-induced Fas promoter activity. Increased Fas promoter activity was paralleled by enhanced susceptibility of PIC + cytokine-treated beta-cells to apoptosis induced by Fas ligand. beta-Cell infection with the NF-kappa B inhibitor AdI kappa B((SA)2) prevented both necrosis and apoptosis induced by PIC + IL-1 beta or PIC + IFN-gamma. Messenger RNAs for several chemokines and one cytokine were induced by PIC, alone or in combination with IFN-gamma, in pancreatic beta-cells. These included IP-10, interferon-gamma-inducible protein-10, IL-15, macrophage chemoattractant protein-1, fractalkine, and macrophage inflammatory protein-3 alpha. There was not, however, induction of IL-1 beta expression. We propose that dsRNA, generated during a viral infection, may contribute for beta-cell demise by both inducing expression of chemokines and IL-15, putative contributors for the build-up of insulitis, and by synergizing with locally produced cytokines to induce beta-cell apoptosis. Activation of the transcription factor NF-kappa B plays a central role in at least part of the deleterious effects of dsRNA in pancreatic beta-cells.
Liu
Dongbo
D
Gene Expression Unit, Diabetes Research Center, Vrije Universiteit Brussel, Brussels B-1070, Belgium.
Cardozo
Alessandra K
AK
Darville
Martine I
MI
Eizirik
Décio L
DL
D000257:Adenoviridae Infections / Q000473:pathology*; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D018925:Chemokines / Q000096:biosynthesis / Q000502:physiology*; D016207:Cytokines / Q000096:biosynthesis; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology* / Q000821:virology*; D053222:Fas Ligand Protein; D007328:Insulin / Q000096:biosynthesis; D007371:Interferon-gamma / Q000494:pharmacology*; D007375:Interleukin-1 / Q000494:pharmacology*; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D008156:Luciferases / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000494:pharmacology; D016328:NF-kappa B / Q000502:physiology*; D011070:Poly I-C / Q000494:pharmacology; D012330:RNA, Double-Stranded / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000302:isolation & purification; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
D018925:Chemokines; D016207:Cytokines; D053222:Fas Ligand Protein; C505662:Faslg protein, rat; D007328:Insulin; D007375:Interleukin-1; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D012330:RNA, Double-Stranded; D012333:RNA, Messenger; D007371:Interferon-gamma; D008156:Luciferases; D011070:Poly I-C