The overarching goal of the proposed research is to directly test the validity of the oxidative stress hypothesis of aging by determining the effects of genetic manipulations of the antioxidative defenses in Drosophila melanogaster. The specific hypothesis to be tested in the present study is that experimental augmentation of the glutathione (GSH) - NADPH system would lower the level of oxidative stress thereby slowing the rate of the aging process, while a decrease in the efficiency of this system would elevate the level of oxidative stress and accelerate the aging process. GSH and NADPH provide the bulk of the reducing power in cells and act in concert to eliminate various reactive oxygen species (ROS). Enhancement of cellular ability to synthesize GSH and NADPH will be achieved by transgenic overexpression of y-glutamate-cysteine ligase subunits (GCL) and glucose-6-phosphate dehydrogenase (G6PH), respectively, in D. melanogaster. The four specific aims are: (I) Determine the effects of over and under expression of GCL in different regions of the body and at different periods of life cycle on the aging process. (II) Determine the effects of over and under expression of glucose-6-phosphate dehydrogenase (G6PD) in different regions of the body and at different periods of the life cycle on the aging process. (Ill) Determine the effects of co-overexpression of GCL and G6PD on the life span and patterns of physiological aging. (IV) Determine the effects of over and under expression of GCL and G6PD on the redox state of tissues indicated by GSH, GSSG, mixed protein disulfides, NADPH, NADP+, NADH and NAD+. The most compelling rationale for these studies is that our recent findings indicate that overexpression of GCL (catalytic subunit) and G6PD increases life span of relatively long-lived strains of flies by up to 50%. Results of the prospective studies would directly test the predictions of the oxidative stress hypothesis of aging and indicate whether augmentation of cellular reductive capacity can significantly extend the life span of flies.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
5R01AG015122-13
Application #
7798011
Study Section
Special Emphasis Panel (ZRG1-BDA-A (02))
Program Officer
Finkelstein, David B
Project Start
1997-12-01
Project End
2012-03-31
Budget Start
2010-04-01
Budget End
2012-03-31
Support Year
13
Fiscal Year
2010
Total Cost
$294,512
Indirect Cost
Name
Southern Methodist University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
001981133
City
Dallas
State
TX
Country
United States
Zip Code
75205
Orr, William C; Radyuk, Svetlana N; Sohal, Rajindar S (2013) Involvement of redox state in the aging of Drosophila melanogaster. Antioxid Redox Signal 19:788-803
Radyuk, Svetlana N; Klichko, Vladimir I; Michalak, Katarzyna et al. (2013) The effect of peroxiredoxin 4 on fly physiology is a complex interplay of antioxidant and signaling functions. FASEB J 27:1426-38
Sohal, Rajindar S; Orr, William C (2012) The redox stress hypothesis of aging. Free Radic Biol Med 52:539-555
Radyuk, Svetlana N; Gambini, Juan; Borras, Consuelo et al. (2012) Age-dependent changes in the transcription profile of long-lived Drosophila over-expressing glutamate cysteine ligase. Mech Ageing Dev 133:401-13
Radyuk, Svetlana N; Rebrin, Igor; Klichko, Vladimir I et al. (2010) Mitochondrial peroxiredoxins are critical for the maintenance of redox state and the survival of adult Drosophila. Free Radic Biol Med 49:1892-902
Radyuk, Svetlana N; Rebrin, Igor; Luchak, James M et al. (2009) The catalytic subunit of Drosophila glutamate-cysteine ligase is a nucleocytoplasmic shuttling protein. J Biol Chem 284:2266-74
Legan, Susan K; Rebrin, Igor; Mockett, Robin J et al. (2008) Overexpression of glucose-6-phosphate dehydrogenase extends the life span of Drosophila melanogaster. J Biol Chem 283:32492-9
Toroser, Dikran; Yarian, Connie S; Orr, William C et al. (2006) Mechanisms of gamma-glutamylcysteine ligase regulation. Biochim Biophys Acta 1760:233-44
Orr, William C; Radyuk, Svetlana N; Prabhudesai, Leena et al. (2005) Overexpression of glutamate-cysteine ligase extends life span in Drosophila melanogaster. J Biol Chem 280:37331-8
Rebrin, Igor; Bayne, Anne-Cecile V; Mockett, Robin J et al. (2004) Free aminothiols, glutathione redox state and protein mixed disulphides in aging Drosophila melanogaster. Biochem J 382:131-6

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