Cell death induced by oxidative stress occurs during ischemia/reperfusion, leading to failure of different organs such as the heart, brain, liver, and/or kidneys. Furthermore, oxidative stress is often the mediator of drug-and toxicant-induced cell death. Our previous studies in renal cells suggested that inhibition of calcium-independent phospholipase A2 (iPLA2) with the iPLA2 inhibitor bromoenol lactone (BEL) potentiated lipid peroxidation and necrotic cell death induced by oxidants. These results led us to the hypothesis that iPLA2 acts to repair or prevent lipid peroxidation induced by oxidants. We have identified IPLA2 gamma (Group VIB) in renal cells and localized it to the endoplasmic reticulum (ER). Exciting new preliminary studies have revealed that iPLA2 gamma also is present in the mitochondria of renal cells. The localization of a protein to both the ER and mitochondria is rare and limited to few other proteins. It should be noted that the major sources of reactive oxygen species in cells, ER and mitochondria, coincide with IPLA2 gamma localization. Our current hypothesis is that iPLA2 gamma protects cells from oxidative stress by preserving endoplasmic reticulum and mitochondrial membrane integrity and function. We propose to investigate this hypothesis through the following Specific Aims:
Specific Aim 1. Determine the mechanism by which iPLA2 gamma is targeted to the ER and mitochondria.
Specific Aim 2. Determine the consequences of """"""""over-expression"""""""" and """"""""knock-down"""""""" of iPLA2 gamma on ER and mitochondrial functions and necrotic cell death following oxidative stress.
Specific Aim 3. Determine the mechanism(s) by which iPLA gamma protects ER and mitochondria during oxidative stress. Successful completion of these aims will increase our limited knowledge on the targeting of proteins to multiple cellular locations and elucidate the function of iPLA2 gamma, a potential natural defense enzyme against oxidative stress in the mitochondria and ER. Ultimately, these studies may lead to new therapeutic and pharmacological approaches to increase cell and organ survival in numerous pathologic situations. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
2R01DK062028-04A2
Application #
7208288
Study Section
Surgery, Anesthesiology and Trauma Study Section (SAT)
Program Officer
Rys-Sikora, Krystyna E
Project Start
2002-03-15
Project End
2010-11-30
Budget Start
2007-01-01
Budget End
2007-11-30
Support Year
4
Fiscal Year
2007
Total Cost
$366,711
Indirect Cost
Name
University of South Carolina at Columbia
Department
Pharmacology
Type
Schools of Pharmacy
DUNS #
041387846
City
Columbia
State
SC
Country
United States
Zip Code
29208
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Wills, Lauren P; Trager, Richard E; Beeson, Gyda C et al. (2012) The ?2-adrenoceptor agonist formoterol stimulates mitochondrial biogenesis. J Pharmacol Exp Ther 342:106-18
Wills, Lauren P; Schnellmann, Rick G (2011) Telomeres and telomerase in renal health. J Am Soc Nephrol 22:39-41
Eaddy, Andre C; Schnellmann, Rick G (2011) Visualization and quantification of endoplasmic reticulum Ca2+ in renal cells using confocal microscopy and Fluo5F. Biochem Biophys Res Commun 404:424-7
Blum, Jason L; Kinsey, Gilbert R; Monian, Prashant et al. (2011) Profiling of fatty acids released during calcium-induced mitochondrial permeability transition in isolated rabbit kidney cortex mitochondria. Toxicol In Vitro 25:1001-6
Wills, Lauren P; Schnellmann, Rick G (2010) Telomere shortening and regenerative capacity after acute kidney injury. J Am Soc Nephrol 21:202-4
Zhuang, Shougang; Lu, Bo; Daubert, Rebecca A et al. (2009) Suramin promotes recovery from renal ischemia/reperfusion injury in mice. Kidney Int 75:304-11
Kinsey, Gilbert R; Blum, Jason L; Covington, Marisa D et al. (2008) Decreased iPLA2gamma expression induces lipid peroxidation and cell death and sensitizes cells to oxidant-induced apoptosis. J Lipid Res 49:1477-87
Zhuang, Shougang; Kinsey, Gilbert R; Yan, Yan et al. (2008) Extracellular signal-regulated kinase activation mediates mitochondrial dysfunction and necrosis induced by hydrogen peroxide in renal proximal tubular cells. J Pharmacol Exp Ther 325:732-40
Kinsey, Gilbert R; McHowat, Jane; Patrick, Kennerly S et al. (2007) Role of Ca2+-independent phospholipase A2gamma in Ca2+-induced mitochondrial permeability transition. J Pharmacol Exp Ther 321:707-15

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