Abstract
Wound and subsequent healing are frequently associated with hypoxia. Although hypoxia induces angiogenesis for tissue remodeling during wound healing, it may also affect the healing response of parenchymal cells. Whether and how wound healing is affected by hypoxia in kidney cells and tissues is currently unknown. Here, we used scratch-wound healing and transwell migration models to examine the effect of hypoxia in cultured renal proximal tubular cells (RPTC). Wound healing and migration were significantly slower in hypoxic (1% oxygen) RPTC than normoxic (21% oxygen) cells. Hypoxia-inducible factor-1α (HIF-1α) was induced during scratch-wound healing in normoxia, and the induction was more evident in hypoxia. Nevertheless, HIF-1α-null and wild-type cells healed similarly after scratch wounding. Moreover, activation of HIF-1α with dimethyloxalylglycine in normoxic cells did not suppress wound healing, negating a major role of HIF-1α in wound healing in this model. Scratch-wound healing was also associated with glycogen synthase kinase 3β (GSK3β)/β-catenin signaling, which was further enhanced by hypoxia. Pharmacological inhibition of GSK3β resulted in β-catenin expression, accompanied by the suppression of wound healing and transwell cell migration. Ectopic expression of β-catenin in normoxic cells could also suppress wound healing, mimicking the effect of hypoxia. Conversely, inhibition of β-catenin via dominant negative mutants or short hairpin RNA improved wound healing and transwell migration in hypoxic cells. The results suggest that GSK3β/β-catenin signaling may contribute to defective wound healing in hypoxic renal cells and tissues.
Footnotes
The study was supported in part by the National Institutes of Health National Institute of Diabetes and Digestive and Kidney Diseases [Grants DK-058831, DK-087843] and a VA Merit grant.
J.P. is an exchange graduate student conducting thesis research at Georgia Health Sciences University, as part of the International Cooperative Agreement between Georgia Health Sciences University and Wuhan University in China.
Z.D. is a Research Career Scientist of the Department of Veterans Affairs.
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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ABBREVIATIONS:
- HIF
- hypoxia-inducible factor
- DMOG
- dimethyloxalylglycine
- GSK3β
- glycogen synthase kinase 3β
- MEF
- mouse embryonic fibroblast
- RPTC
- renal proximal tubular cells
- LiCl
- lithium chloride
- shRNA
- short hairpin RNA
- HEK
- human embryonic kidney
- PI
- propidium iodide
- SB216763
- 3-(2,4-dichlorophenyl)-4-(1-methyl-1H-indol-3-yl)-1H-pyrrole-2,5-dione.
- Received August 29, 2011.
- Accepted October 17, 2011.
- Copyright © 2012 by The American Society for Pharmacology and Experimental Therapeutics
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