title: A20 inhibits cytokine-induced apoptosis and nuclear factor kappaB-dependent gene activation in islets.
abstract: Insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease resulting from apoptotic destruction of beta cells in the islets of Langerhans. Low expression of antioxidants and a predilection to produce nitric oxide (NO) have been shown to underscore beta cell apoptosis. With this perspective in mind, we questioned whether beta cells could mount an induced protective response to inflammation. Here we show that human and rat islets can be induced to rapidly express the antiapoptotic gene A20 after interleukin (IL)-1beta activation. Overexpression of A20 by means of adenovirus-mediated gene transfer protects islets from IL-1beta and interferon gamma-induced apoptosis. The cytoprotective effect of A20 against apoptosis correlates with and is dependent on the abrogation of cytokine-induced NO production. The inhibitory effect of A20 on cytokine-stimulated NO production is due to transcriptional blockade of inducible NO synthase (iNOS) induction; A20 inhibits the activation of the transcription factor nuclear factor kappaB at a level upstream of IkappaBalpha degradation. These data demonstrate a dual antiapoptotic and antiinflammatory function for A20 in beta cells. This qualifies A20 as part of the physiological cytoprotective response of islets. We propose that A20 may have therapeutic potential as a gene therapy candidate to achieve successful islet transplantation and the cure of IDDM.
authors.affiliation: Immunobiology Research Center, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA. sgrey@caregroup.harvard.edu
authors.forename: S T
authors.initials: ST
authors.lastname: Grey
authors.forename: M B
authors.initials: MB
authors.lastname: Arvelo
authors.forename: W
authors.initials: W
authors.lastname: Hasenkamp
authors.forename: F H
authors.initials: FH
authors.lastname: Bach
authors.forename: C
authors.initials: C
authors.lastname: Ferran
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002460:Cell Line; D003546:Cysteine Endopeptidases; D016207:Cytokines / Q000494:pharmacology*; D004268:DNA-Binding Proteins; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000276:immunology; D005786:Gene Expression Regulation / Q000187:drug effects; D015316:Genetic Therapy; D006801:Humans; D007249:Inflammation / Q000276:immunology; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000378:metabolism / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D007515:Islets of Langerhans / Q000187:drug effects*; D051379:Mice; D016328:NF-kappa B / Q000235:genetics*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D009687:Nuclear Proteins; D011506:Proteins / Q000235:genetics / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015533:Transcriptional Activation; D014162:Transfection; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3
chemical_list: D016207:Cytokines; D004268:DNA-Binding Proteins; D007375:Interleukin-1; D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B; D009687:Nuclear Proteins; D011506:Proteins; D009569:Nitric Oxide; D007371:Interferon-gamma; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; C496318:Nos2 protein, rat; C076529:TNFAIP3 protein, human; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D003546:Cysteine Endopeptidases; C513261:Tnfaip3 protein, mouse