Loss of Nix in Pdx1-deficient mice prevents apoptotic and necrotic β cell death and diabetes.
Ontology highlight
ABSTRACT:
SUBMITTER: Fujimoto K
PROVIDER: S-EPMC2964996 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Mutations of the pancreatic duodenal homeobox gene-1, Pdx1, cause heritable diabetes in humans and mice. A central abnormality with Pdx1 deficiency is increased death of beta-cells, leading to decreased beta-cell mass. We show that lentiviral suppression of Pdx1 increases death of mouse insulinoma MIN6 beta-cells associated with dissipation of the mitochondrial inner membrane electrochemical gradient, Deltapsi(m). Preventing mitochondrial permeability transition pore opening with the cyclophilin D inhibitor cyclosporin A restored Deltapsi(m) and rescued cell viability. Reduced beta-cell mass, markers of beta-cell apoptosis, necrosis, and decreased proliferation are present in Pdx1 haploinsufficient mice. Genetic ablation of the Ppif gene, encoding cyclophilin D, restored beta-cell mass and decreased TUNEL and complement complex labeling without affecting beta-cell proliferation. In adult mice maintained on a high-fat diet, Ppif ablation normalized fasting glucose and glucose and insulin responses to acute glucose challenge. Thus, cyclophilin D and the mitochondrial permeability transition are critical regulators of beta-cell death caused by Pdx1 insufficiency.
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