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Title

Glucagon-like peptide-1 receptor signaling modulates beta cell apoptosis

Authors
Li, Yazhou
Hansotia, Tanya
Yusta, Bernardo
Drucker, D. J.
Published in Journal of Biological Chemistry. 2003, vol. 278, no. 1, p. 471-478
Abstract Glucagon-like peptide-1 (GLP-1) stimulates insulin secretion and augments beta cell mass via activation of beta cell proliferation and islet neogenesis. We examined whether GLP-1 receptor signaling modifies the cellular susceptibility to apoptosis. Mice administered streptozotocin (STZ), an agent known to induce beta cell apoptosis, exhibit sustained improvement in glycemic control and increased levels of plasma insulin with concomitant administration of the GLP-1 agonist exendin-4 (Ex-4). Blood glucose remained significantly lower for weeks after cessation of exendin-4. STZ induced beta cell apoptosis, which was significantly reduced by co-administration of Ex-4. Conversely, mice with a targeted disruption of the GLP-1 receptor gene exhibited increased beta cell apoptosis after STZ administration. Exendin-4 directly reduced cytokine-induced apoptosis in purified rat beta cells exposed to interleukin 1beta, tumor necrosis fator alpha, and interferon gamma in vitro. Furthermore, Ex-4-treated BHK-GLP-1R cells exhibited significantly increased cell viability, reduced caspase activity, and decreased cleavage of beta-catenin after treatment with cycloheximide in vitro. These findings demonstrate that GLP-1 receptor signaling directly modifies the susceptibility to apoptotic injury, and provides a new potential mechanism linking GLP-1 receptor activation to preservation or enhancement of beta cell mass in vivo.
Keywords AnimalsApoptosis/ physiologyBlood Glucose/metabolismCell LineCell SurvivalCricetinaeCycloheximide/pharmacologyCytokines/metabolismCytoskeletal Proteins/metabolismDiabetes Mellitus, ExperimentalForskolin/pharmacologyGlucagon/agonists/ metabolismGlucagon-Like Peptide 1Glucose Tolerance TestIn Situ Nick-End LabelingInsulin/bloodIslets of Langerhans/drug effects/ physiologyMaleMiceMice, Inbred C57BLMice, KnockoutPeptide Fragments/agonists/ metabolismPeptides/pharmacologyProtein Precursors/agonists/ metabolismProtein Synthesis Inhibitors/pharmacologyRatsRats, WistarReceptors, Glucagon/agonists/genetics/ metabolismSignal Transduction/ physiologyStreptozocin/administration & dosageTrans-Activators/metabolismVenomsBeta Catenin
Identifiers
PMID: 12409292
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Other version: http://www.jbc.org/content/278/1/471.full.pdf
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LI, Yazhou et al. Glucagon-like peptide-1 receptor signaling modulates beta cell apoptosis. In: Journal of Biological Chemistry, 2003, vol. 278, n° 1, p. 471-478. https://archive-ouverte.unige.ch/unige:8860

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Deposited on : 2010-07-12

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