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 #
5R01ES016005-02
Application #
7686956
Study Section
Special Emphasis Panel (ZES1-JAB-C (R2))
Program Officer
Heindel, Jerrold
Project Start
2008-09-12
Project End
2013-05-31
Budget Start
2009-06-01
Budget End
2010-05-31
Support Year
2
Fiscal Year
2009
Total Cost
$567,781
Indirect Cost
Name
The Hamner Institutes
Department
Type
DUNS #
040052250
City
Research Triangle Park
State
NC
Country
United States
Zip Code
27709
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