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Signaling by IL-1beta+IFN-gamma and ER stress converge on DP5/Hrk activation: a novel mechanism for pancreatic beta-cell apoptosis.

par Gurzov, Esteban Nicolas ;Ortis, Fernanda ;Andrade Da Cunha, Daniel ;Gosset, Geoffrey ;Li, M;Cardozo, Alessandra K ;Eizirik, Decio L.
Référence Cell death and differentiation, 16, 11, page (1539-1550)
Publication Publié, 2009

Article révisé par les pairs

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Résumé :

Chronic inflammation and pro-inflammatory cytokines are important mediators of pancreatic beta-cell destruction in type 1 diabetes (T1D). We presently show that the cytokines IL-1beta+IFN-gamma and different ER stressors activate the Bcl-2 homology 3 (BH3)-only member death protein 5 (DP5)/harakiri (Hrk) resulting in beta-cell apoptosis. Chemical ER stress-induced DP5 upregulation is JNK/c-Jun-dependent. DP5 activation by cytokines also involves JNK/c-Jun phosphorylation and is antagonized by JunB. Interestingly, cytokine-inducted DP5 expression precedes ER stress: mitochondrial release of cytochrome c and ER stress are actually a consequence of enhanced DP5 activation by cytokine-mediated nitric oxide formation. Our findings show that DP5 is central for beta-cell apoptosis after different stimuli, and that it can act up- and downstream of ER stress. These observations contribute to solve two important questions, namely the mechanism by which IL-1beta+IFN-gamma induce beta-cell death and the nature of the downstream signals by which ER stress 'convinces' beta-cells to trigger apoptosis.