Abstract

The unifying hypothesis of the program project is that altered glycolytic flux in diabetes results in the dysfunctional regulation of calcium- independent phospholipase A2 in the heart and blood vessels. This project examines the role of the dysfunctional regulation of the glycolytically-coupled generation of lipid second messengers by calcium- independent phospholipase A2 in the pathogenesis of contractile dysfunction in diabetic myocardium and the increased susceptibility of diabetic myocardium to acute ischemia. We have demonstrated that diabetic myocardium exhibits three hallmarks of pathologic alterations in lipid metabolism including: 1) dramatic depletion of the arachidonic acid content present in its endogenous phospholipid storage depots; 2) markedly increased levels of calcium-independent phospholipase A2 activity; and 3) abnormal fluxes of arachidonic acid into and out of myocytic phospholipid pools. Accordingly, Specific Aim 1 will examine the importance of the coupling of glycolytic flux with arachidonic acid release and lysophospholipid generation in diabetic myocardium. The role of calcium-independent phospholipase A2 in this process will be determined by exploiting the specificity inherent in the mechanism-based inhibitor (E)-6-(bromomethylene)-3-(1-naphthalenyl)-2-H-tetrahydropyran- 2-one(BEL). Next, the role of accelerated membrane hydrolysis by calcium-independent phospholipase A2 in mediating the increased susceptibility of diabetic myocardium to ischemic injury will be explored.
In Specific Aim 2, the heterogeneity of arachidonic acid depletion in myocardial subcellular membrane compartments in diabetic myocardium will be examined by exploiting the power and sensitivity of electrospray ionization mass spectrometry. Alterations of lipid flux in specific subcellular membrane loci in the diabetic state will be identified utilizing quantitative electron microscopic autoradiography and the role of calcium-independent phospholipase A2 in this process will be determined utilizing BEL.
In Specific Aim 3, the mechanisms underlying the marked increase in calcium-independent phospholipase A2 activity in diabetic myocardium will be identified by analysis of alterations in calcium-independent phospholipase A2 mass, isoform composition and/or post-translational modifications in the diabetic state. Collectively, these studies represent a multidisciplinary approach targeted at identifying the importance of glycolytic coupling of lipid second messenger generation to cardiac dysfunction in the diabetic state.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
5P01HL057278-04
Application #
6202549
Study Section
Project Start
1999-09-01
Project End
2000-08-31
Budget Start
1997-10-01
Budget End
1998-09-30
Support Year
4
Fiscal Year
1999
Total Cost
Indirect Cost

  Institution

Name
Washington University
Department
Type
DUNS #
062761671
City
Saint Louis
State
MO
Country
United States
Zip Code
63130

  Publications

Beirowski, Bogdan; Babetto, Elisabetta; Golden, Judith P et al. (2014) Metabolic regulator LKB1 is crucial for Schwann cell-mediated axon maintenance. Nat Neurosci 17:1351-61
Lei, Xiaoyong; Bone, Robert N; Ali, Tomader et al. (2014) Evidence of contribution of iPLA2?-mediated events during islet ?-cell apoptosis due to proinflammatory cytokines suggests a role for iPLA2? in T1D development. Endocrinology 155:3352-64
Pacheco, Sophia A; Hsu, Fong-Fu; Powers, Katelyn M et al. (2013) MmpL11 protein transports mycolic acid-containing lipids to the mycobacterial cell wall and contributes to biofilm formation in Mycobacterium smegmatis. J Biol Chem 288:24213-22
Lei, Xiaoyong; Bone, Robert N; Ali, Tomader et al. (2013) Genetic modulation of islet ?-cell iPLA?? expression provides evidence for its impact on ?-cell apoptosis and autophagy. Islets 5:29-44
Kuda, Ondrej; Pietka, Terri A; Demianova, Zuzana et al. (2013) Sulfo-N-succinimidyl oleate (SSO) inhibits fatty acid uptake and signaling for intracellular calcium via binding CD36 lysine 164: SSO also inhibits oxidized low density lipoprotein uptake by macrophages. J Biol Chem 288:15547-55
Yang, Kui; Dilthey, Beverly Gibson; Gross, Richard W (2013) Identification and quantitation of fatty acid double bond positional isomers: a shotgun lipidomics approach using charge-switch derivatization. Anal Chem 85:9742-50
Viader, Andreu; Sasaki, Yo; Kim, Sungsu et al. (2013) Aberrant Schwann cell lipid metabolism linked to mitochondrial deficits leads to axon degeneration and neuropathy. Neuron 77:886-98
Kiebish, Michael A; Yang, Kui; Liu, Xinping et al. (2013) Dysfunctional cardiac mitochondrial bioenergetic, lipidomic, and signaling in a murine model of Barth syndrome. J Lipid Res 54:1312-25
Jenkins, Christopher M; Yang, Jingyue; Gross, Richard W (2013) Mechanism-based inhibition of iPLA2? demonstrates a highly reactive cysteine residue (C651) that interacts with the active site: mass spectrometric elucidation of the mechanisms underlying inhibition. Biochemistry 52:4250-63
Abumrad, Nada A; Davidson, Nicholas O (2012) Role of the gut in lipid homeostasis. Physiol Rev 92:1061-85

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