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Toll-like receptor 3 and STAT-1 contribute to double-stranded RNA+ interferon-gamma-induced apoptosis in primary pancreatic beta-cells.

par Rasschaert, Joanne ;Ladrière, Laurence ;Urbain, Maryse ;Dogusan, Zeynep ;Katabua, Bitshilualua ;Sato, Shintaro;Akira, Shizuo;Gysemans, Conny A;Mathieu, Chantal;Eizirik, Decio L.
Référence The Journal of biological chemistry, 280, 40, page (33984-33991)
Publication Publié, 2005

Article révisé par les pairs

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Résumé :

Viral infections and local production of cytokines probably contribute to the pathogenesis of Type 1 diabetes. The viral replicative intermediate double-stranded RNA (dsRNA, tested in the form of polyinosinic-polycytidylic acid, PIC), in combination with the cytokine interferon-gamma (IFN-gamma), triggers beta-cell apoptosis. We have previously observed by microarray analysis that PIC induces expression of several mRNAs encoding for genes downstream of Toll-like receptor 3 (TLR3) signaling pathway. In this report, we show that exposure of beta-cells to dsRNA in combination with IFN-alpha, -beta, or -gamma significantly increases apoptosis. Moreover, dsRNA induces TLR3 mRNA expression and activates NF-kappaB and the IFN-beta promoter in a TRIF-dependent manner. dsRNA also induces an early (1 h) and sustained increase in IFN-beta mRNA expression, and blocking IFN-beta with a specific antibody partially prevents PIC plus IFN-gamma-induced beta-cell death. On the other hand, dsRNA plus IFN-gamma does not induce apoptosis in INS-1E cells, and expression of TLR3 and type I IFNs mRNAs is not detected in these cells. Of note, disruption of the STAT-1 signaling pathway protects beta-cells against dsRNA plus IFN-gamma-induced beta-cell apoptosis. This study suggests that dsRNA plus IFN-gamma triggers beta-cell apoptosis by two complementary pathways, namely TLR3-TRIF-NF-kappaB and STAT-1.