Double-stranded ribonucleic acid (RNA) induces beta-cell Fas messenger RNA expression and increases cytokine-induced beta-cell apoptosis

Endocrinology. 2001 Jun;142(6):2593-9. doi: 10.1210/endo.142.6.8188.

Abstract

Type 1 diabetes mellitus (T1DM) is an autoimmune disease caused by progressive destruction of insulin-producing pancreatic beta-cells. Both viral infections and the cytokines interleukin-1beta (IL-1beta) and interferon-gamma (IFN-gamma) have been suggested as potential mediators of beta-cell death in early T1DM. We presently investigated whether the viral replicative intermediate double stranded RNA [here used as synthetic polyinosinic-polycytidylic acid (PIC)] modifies the effects of IL-1beta and IFN-gamma on gene expression and viability of rat pancreatic beta-cells. For this purpose, fluorescence-activated cell sorting-purified rat beta-cells were exposed for 6-16 h (study of gene expression by RT-PCR) or 6-9 days (study of viability by nuclear dyes) to PIC and/or IL-1beta and IFN-gamma. PIC increased the expression of Fas and Mn superoxide dismutase messenger RNAs by 5- to 10-fold. IL-1beta and a combination of PIC and IFN-gamma (but not PIC or IFN-gamma alone) induced expression of inducible nitric oxide (NO) synthase (iNOS) and consequent NO production. Induction of iNOS expression by PIC and IFN-gamma requires nuclear factor-kappaB activation, as suggested by transfection experiments with iNOS promoter-luciferase reporter constructs into primary beta-cells. Combinations of IL-1beta plus IFN-gamma, PIC plus IFN-gamma, or PIC plus IL-1beta induced a 2- to 3-fold increase in the number of apoptotic beta-cells. Blocking of iNOS activity significantly decreased PIC- plus IL-1beta-induced, but not PIC- plus IFN-gamma-induced, apoptosis. In conclusion, PIC alone or in combination with cytokines modifies the expression of several genes in pancreatic beta-cells. Two of these genes, Fas and iNOS, may contribute to beta-cell death. The transcription factor nuclear factor-kappaB is required for PIC-induced iNOS expression. PIC has an additive effect on cytokine-induced beta-cell death by both NO-dependent (in the case of IL-1beta) and NO-independent (in the case of IFN-gamma) mechanisms. These findings suggest that viral intermediates in synergism with local cytokine production may play an important role in beta-cell apoptosis in early T1DM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis*
  • Cells, Cultured
  • Cytokines / pharmacology*
  • Flow Cytometry
  • Gene Expression / drug effects*
  • Glyceraldehyde-3-Phosphate Dehydrogenases / genetics
  • Interferon-gamma / pharmacology
  • Interleukin-1 / pharmacology
  • Islets of Langerhans / cytology
  • Islets of Langerhans / metabolism*
  • Luciferases / genetics
  • Male
  • NF-kappa B / physiology
  • Nitric Oxide / biosynthesis
  • Nitric Oxide Synthase / genetics
  • Nitric Oxide Synthase Type II
  • Poly I-C / pharmacology
  • Promoter Regions, Genetic
  • RNA, Double-Stranded / pharmacology*
  • RNA, Messenger / analysis*
  • Rats
  • Rats, Wistar
  • Recombinant Fusion Proteins
  • Superoxide Dismutase / genetics
  • Transfection
  • fas Receptor / genetics*

Substances

  • Cytokines
  • Interleukin-1
  • NF-kappa B
  • RNA, Double-Stranded
  • RNA, Messenger
  • Recombinant Fusion Proteins
  • fas Receptor
  • Nitric Oxide
  • Interferon-gamma
  • Luciferases
  • Nitric Oxide Synthase
  • Nitric Oxide Synthase Type II
  • Nos2 protein, rat
  • Superoxide Dismutase
  • Glyceraldehyde-3-Phosphate Dehydrogenases
  • Poly I-C