Oxidant-induced Vascular Endothelial Growth Factor Expression in Human Keratinocytes and Cutaneous Wound Healing

• Published in: The Journal of biological chemistry 2002-09, Vol.277 (36), p.33284-33290
• Main Authors: Sen, Chandan K., Khanna, Savita, Babior, Bernard M., Hunt, Thomas K., Ellison, E. Christopher, Roy, Sashwati
• Format: Article
• Language: English
• Subjects: Animals; Cell Line; Collagen - metabolism; Endothelial Growth Factors - metabolism; Gene Deletion; Gene Transfer Techniques; Green Fluorescent Proteins; Humans; Hydrogen Peroxide - pharmacology; Immunoblotting; Keratinocytes - metabolism; Luciferases - metabolism; Luminescent Proteins - metabolism; Lymphokines - metabolism; Male; Mice; Mice, Inbred BALB C; Microscopy, Fluorescence; NADPH Oxidases - metabolism; Neovascularization, Pathologic; Oxidants - pharmacology; Oxidation-Reduction; Phosphotyrosine - metabolism; Plasmids - metabolism; Precipitin Tests; Promoter Regions, Genetic; rac1 GTP-Binding Protein - metabolism; Reverse Transcriptase Polymerase Chain Reaction; Ribonucleases - metabolism; Skin - pathology; Skin Physiological Phenomena; Time Factors; Transcriptional Activation; Transfection; Tumor Cells, Cultured; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors; Wound Healing
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M203391200

Neutrophils and macrophages, recruited to the wound site, release reactive oxygen species by respiratory burst. It is commonly understood that oxidants serve mainly to kill bacteria and prevent wound infection. We tested the hypothesis that oxidants generated at the wound site promote dermal wound repair. We observed that H2O2 potently induces vascular endothelial growth factor (VEGF) expression in human keratinocytes. Deletion mutant studies with a VEGF promoter construct revealed that a GC-rich sequence from bp −194 to −50 of the VEGF promoter is responsible for the H2O2 response. It was established that at μm concentrations oxidant induces VEGF expression and that oxidant-induced VEGF expression is independent of hypoxia-inducible factor (HIF)-1 and dependent on Sp1 activation. To test the effect of NADPH oxidase-generated reactive oxygen species on wound healing in vivo, Rac1 gene transfer was performed to dermal excisional wounds left to heal by secondary intention. Rac1 gene transfer accelerated wound contraction and closure. Rac1 overexpression was associated with higher VEGF expression both in vivo as well in human keratinocytes. Interestingly, Rac1 gene therapy was associated with a more well defined hyperproliferative epithelial region, higher cell density, enhanced deposition of connective tissue, and improved histological architecture. Overall, the histological data indicated that Rac1 might be an important stimulator of various aspects of the repair process, eventually enhancing the wound-healing process as a whole. Taken together, the results of this study indicate that wound healing is subject to redox control.