JunB Inhibits ER Stress and Apoptosis in Pancreatic Beta Cells

Esteban Gurzov, Fernanda Ortis, Latifa Bakiri, Erwin Wagner, Decio Eizirk

Research output: Contribution to journalArticleResearchpeer-review

45 Citations (Scopus)

Abstract

Cytokines contribute to pancreatic beta-cell apoptosis in type 1 diabetes (T1D) by modulation of beta-cell gene expression networks. The transcription factor Activator Protein-1 (AP-1) is a key regulator of inflammation and apoptosis. We presently evaluated the function of the AP-1 subunit JunB in cytokine-mediated beta-cell dysfunction and death. The cytokines IL-1beta+IFN-gamma induced an early and transitory upregulation of JunB by NF-kappaB activation. Knockdown of JunB by RNA interference increased cytokine-mediated expression of inducible nitric oxide synthase (iNOS) and endoplasmic reticulum (ER) stress markers, leading to increased apoptosis in an insulin-producing cell line (INS-1E) and in purified rat primary beta-cells. JunB knockdown beta-cells and junB(-/-) fibroblasts were also more sensitive to the chemical ER stressor cyclopiazonic acid (CPA). Conversely, adenoviral-mediated overexpression of JunB diminished iNOS and ER markers expression and protected beta-cells from cytokine-induced cell death. These findings demonstrate a novel and unexpected role for JunB as a regulator of defense mechanisms against cytokine- and ER stress-mediated apoptosis.
Original languageEnglish
Pages (from-to)e3030.1 - e3030.10
Number of pages10
JournalPLoS ONE
Volume3
Issue number8
DOIs
Publication statusPublished - 2008
Externally publishedYes

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