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beta-Cell-specific overexpression of glutathione peroxidase preserves intranuclear MafA and reverses diabetes in db/db mice.

Authors: Harmon, JS  Bogdani, M  Parazzoli, SD  Mak, SS  Oseid, EA  Berghmans, M  LeBoeuf, RC  Robertson, RP 
Citation: Harmon JS, etal., Endocrinology. 2009 Nov;150(11):4855-62. doi: 10.1210/en.2009-0708. Epub 2009 Oct 9.
Pubmed: (View Article at PubMed) PMID:19819955
DOI: Full-text: DOI:10.1210/en.2009-0708

Chronic hyperglycemia causes oxidative stress, which contributes to damage in various tissues and cells, including pancreatic beta-cells. The expression levels of antioxidant enzymes in the islet are low compared with other tissues, rendering the beta-cell more susceptible to damage caused by hyperglycemia. The aim of this study was to investigate whether increasing levels of endogenous glutathione peroxidase-1 (GPx-1), specifically in beta-cells, can protect them against the adverse effects of chronic hyperglycemia and assess mechanisms that may be involved. C57BLKS/J mice overexpressing the antioxidant enzyme GPx-1 only in pancreatic beta-cells were generated. The biological effectiveness of the overexpressed GPx-1 transgene was documented when beta-cells of transgenic mice were protected from streptozotocin. The transgene was then introgressed into the beta-cells of db/db mice. Without use of hypoglycemic agents, hyperglycemia in db/db-GPx(+) mice was initially ameliorated compared with db/db-GPx(-) animals and then substantially reversed by 20 wk of age. beta-Cell volume and insulin granulation and immunostaining were greater in db/db-GPx(+) animals compared with db/db-GPx(-) animals. Importantly, the loss of intranuclear musculoaponeurotic fibrosarcoma oncogene homolog A (MafA) that was observed in nontransgenic db/db mice was prevented by GPx-1 overexpression, making this a likely mechanism for the improved glycemic control. These studies demonstrate that enhancement of intrinsic antioxidant defenses of the beta-cell protects it against deterioration during hyperglycemia.


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CRRD Object Information
CRRD ID: 11353779
Created: 2016-07-21
Species: All species
Last Modified: 2016-07-21
Status: ACTIVE


RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.