There is growing evidence that chronic exposure of humans to inorganic arsenic, a potent environmental oxidative stressor, is associated with the incidence of Type 2 diabetes. In contrast to what has been a prevailing beneficial view of antioxidants in preventing pancreatic ?-cell dysfunction in diabetes, this project proposes that in response to arsenic exposure, transcription factor Nrf2-mediated adaptive induction of endogenous antioxidant enzymes plays paradoxical roles in ?-cell function. The investigators hypothesize that, on the one hand, Nrf2-mediated antioxidant response blunts glucose-triggered `ROS signaling'that plays an important role in glucose-stimulated insulin secretion (GSIS);on the other hand, the response protects ?-cells from oxidative damage and subsequent apoptosis/necrosis. The investigators propose three specific aims: (1) Test the hypothesis that induction of antioxidant enzymes in response to arsenic exposure and related oxidative stress impedes glucose-triggered `ROS signaling'and thus GSIS;(2) Test the hypothesis in silico that adaptive induction of antioxidant enzymes in response to chronic oxidative stress impedes `ROS signaling', and explore intervention approaches that can improve `ROS signaling';(3) Test the hypothesis that Nrf2-mediated antioxidant response is critical for protecting ?-cells from oxidative damage and apoptosis/necrosis induced by arsenic and/or glucose toxicity. The integrated wet-lab and computational approaches will allow to: (1) understand how environmental arsenic exposure impairs ?-cell function;(2) characterize the quantitative nature of the effect of arsenic-induced oxidative stress on `ROS signaling'that is involved in GSIS;(3) distinguish the specific roles of Nrf2 and its target antioxidant enzymes in `ROS signaling'and ?-cell function;and (4) identify novel targets and approaches to modulate insulin secretion and protect ?-cells from oxidative damage. This project will investigate the pathogenic mechanisms of Type 2 Diabetes caused by environmental arsenic exposure. The results may enable new therapeutic managements and preventive strategies for arsenic or other environmental oxidative stress-associated diabetes.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
5R01ES016005-05
Application #
8274435
Study Section
Special Emphasis Panel (ZES1-JAB-C (R2))
Program Officer
Heindel, Jerrold
Project Start
2008-09-12
Project End
2014-05-31
Budget Start
2012-06-01
Budget End
2014-05-31
Support Year
5
Fiscal Year
2012
Total Cost
$436,687
Indirect Cost
$173,990
Name
The Hamner Institutes
Department
Type
DUNS #
040052250
City
Research Triangle Park
State
NC
Country
United States
Zip Code
27709
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Xue, Peng; Hou, Yongyong; Chen, Yanyan et al. (2013) Adipose deficiency of Nrf2 in ob/ob mice results in severe metabolic syndrome. Diabetes 62:845-54
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Lv, Peng; Xue, Peng; Dong, Jian et al. (2013) Keap1 silencing boosts lipopolysaccharide-induced transcription of interleukin 6 via activation of nuclear factor *B in macrophages. Toxicol Appl Pharmacol 272:697-702
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Han, Weinong; Ming, Mei; Zhao, Rui et al. (2012) Nrf1 CNC-bZIP protein promotes cell survival and nucleotide excision repair through maintaining glutathione homeostasis. J Biol Chem 287:18788-95
Hou, Yongyong; Xue, Peng; Bai, Yushi et al. (2012) Nuclear factor erythroid-derived factor 2-related factor 2 regulates transcription of CCAAT/enhancer-binding protein ? during adipogenesis. Free Radic Biol Med 52:462-72
Xue, Peng; Hou, Yongyong; Zhang, Qiang et al. (2011) Prolonged inorganic arsenite exposure suppresses insulin-stimulated AKT S473 phosphorylation and glucose uptake in 3T3-L1 adipocytes: involvement of the adaptive antioxidant response. Biochem Biophys Res Commun 407:360-5

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