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Diabetes. 2008 May;57(5):1236-45. doi: 10.2337/db07-0844. Epub 2008 Jan 25.

Double-stranded RNA induces pancreatic beta-cell apoptosis by activation of the toll-like receptor 3 and interferon regulatory factor 3 pathways.

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  • 1Laboratory of Experimental Medicine, Université Libre de Bruxelles, Route de Lennik, 808, CP 618, B-1070 Brussels, Belgium.

Abstract

OBJECTIVE:

Viral infections contribute to the pathogenesis of type 1 diabetes. Viruses, or viral products such as double-stranded RNA (dsRNA), affect pancreatic beta-cell survival and trigger autoimmunity by unknown mechanisms. We presently investigated the mediators and downstream effectors of dsRNA-induced beta-cell death.

RESEARCH DESIGN AND METHODS:

Primary rat beta-cells and islet cells from wild-type, toll-like receptor (TLR) 3, type I interferon receptor (IFNAR1), or interferon regulatory factor (IRF)-3 knockout mice were exposed to external dsRNA (external polyinosinic-polycytidylic acid [PICex]) or were transfected with dsRNA ([PICin]).

RESULTS:

TLR3 signaling mediated PICex-induced nuclear factor-kappaB (NF-kappaB) and IRF-3 activation and beta-cell apoptosis. PICin activated NF-kappaB and IRF-3 in a TLR3-independent manner, induced eukaryotic initiation factor 2 alpha phosphorylation, and triggered a massive production of interferon (IFN)-beta. This contributed to beta-cell death, as islet cells from IFNAR1(-/-) or IRF-3(-/-) mice were protected against PICin-induced apoptosis.

CONCLUSIONS:

PICex and PICin trigger beta-cell apoptosis via the TLR3 pathway or IRF-3 signaling, respectively. Execution of PICin-mediated apoptosis depends on autocrine effects of type I IFNs.

PMID:
18223009
[PubMed - indexed for MEDLINE]
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