VEGF up-regulation by G93A superoxide dismutase and the role of malate-aspartate shuttle inhibition.
A gain of interaction of the amyotrophic lateral sclerosis (ALS)-linked G93A-superoxide dismutase-1 (G93A-hSOD1) with cytosolic malate dehydrogenase (cytMDH), a key enzyme in the malate-aspartate shuttle, diverts neurons towards anaerobic metabolism. Changes in vascular endothelial growth factor (VEGF) are reported in ALS and hypoxia. Here we report that expression of G93A-hSOD1 fused with green fluorescent protein in NSC-34 cells enhanced VEGF expression and levels of VEGF and its upstream regulator hypoxia-inducible factor (HIF-1alpha). G93A-hSOD1 expressing cells were unable to further up-regulated VEGF in response to Co(2+) and H(2)O(2). Amino-oxyacetate that inhibits the malate-aspartate shuttle caused a similar increase in VEGF mRNA and impaired response to H(2)O(2) in WT-hSOD1 expressing cells. Interruption of the G93A-hSOD1/cytMDH interaction reduced VEGF expression in G93A-hSOD1 expressing cells and restored their ability to up-regulate VEGF in response to Co(2+) and H(2)O(2). These results demonstrate that the ALS-linked G93A hSOD1 mutation impairs VEGF regulation compatible with the inhibition of neuronal malate-aspartate shuttle.
Mali
Yael
Y
Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel Aviv 69978, Israel.
Zisapel
Nava
N
D000625:Aminooxyacetic Acid / Q000494:pharmacology; D000690:Amyotrophic Lateral Sclerosis / Q000378:metabolism* / Q000503:physiopathology; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism / Q000494:pharmacology; D002461:Cell Line, Transformed; D004791:Enzyme Inhibitors / Q000494:pharmacology; D049452:Green Fluorescent Proteins; D006825:Hybridomas; D006861:Hydrogen Peroxide / Q000494:pharmacology; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D008293:Malates / Q000378:metabolism*; D053858:Metabolic Networks and Pathways / Q000502:physiology*; D051379:Mice; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism*; D015854:Up-Regulation / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*
D004791:Enzyme Inhibitors; C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008293:Malates; D011993:Recombinant Fusion Proteins; D042461:Vascular Endothelial Growth Factor A; D002245:Carbon Dioxide; D049452:Green Fluorescent Proteins; D000625:Aminooxyacetic Acid; D001224:Aspartic Acid; C030298:malic acid; D006861:Hydrogen Peroxide; C109415:SOD1 G93A protein; D013482:Superoxide Dismutase