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Publication

The molecular basis for impaired hypoxia-induced VEGF expression in diabetic tissues.

Authors Thangarajah H, Yao D, Chang EI, Shi Y, Jazayeri L, Vial IN, Galiano RD, Du XL, Grogan R, Galvez MG, Januszyk M, Brownlee M, Gurtner GC Submitted By Geoffrey Gurtner on 3/31/2010 Status Published Journal Proceedings of the National Academy of Sciences of the United States of America Year 2009 Date Published 8/11/2009 Volume : Pages 106 : 13505 - 13510 PubMed Reference 19666581 Abstract Diabetes is associated with poor outcomes following acute vascular occlusive events. This results in part from a failure to form adequate compensatory microvasculature in response to ischemia. Since vascular endothelial growth factor (VEGF) is an essential mediator of neovascularization, we examined whether hypoxic up-regulation of VEGF was impaired in diabetes. Both fibroblasts isolated from type 2 diabetic patients, and normal fibroblasts exposed chronically to high glucose, were defective in their capacity to up-regulate VEGF in response to hypoxia. In vivo, diabetic animals demonstrated an impaired ability to increase VEGF production in response to soft tissue ischemia. This resulted from a high glucose-induced decrease in transactivation by the transcription factor hypoxia-inducible factor-1alpha (HIF-1alpha), which mediates hypoxia-stimulated VEGF expression. Decreased HIF-1alpha functional activity was specifically caused by impaired HIF-1alpha binding to the coactivator p300. We identify covalent modification of p300 by the dicarbonyl metabolite methylglyoxal as being responsible for this decreased association. Administration of deferoxamine abrogated methylglyoxal conjugation, normalizing both HIF-1alpha/p300 interaction and transactivation by HIF-1alpha. In diabetic mice, deferoxamine promoted neovascularization and enhanced wound healing. These findings define molecular defects that underlie impaired VEGF production in diabetic tissues and offer a promising direction for therapeutic intervention.

Investigators with authorship
Name Institution Geoffrey Gurtner Stanford University

Complications
All ComplicationsBioinformatics BoneCardiomyopathy CardiovascularGastro-Intestinal (GI) NephropathyNeuropathy & Neurocognition Pediatric Endocrinology Retinopathy UropathyWound Healing

Genes
Symbol Description Ep300 E1A binding protein p300 Hif1a hypoxia inducible factor 1, alpha subunit Notch1 Notch gene homolog 1, (Drosophila) Vegfa vascular endothelial growth factor A