M. S. Hu1,2, W. Hong1, M. Xie3, S. Tang3, R. Rennert1, G. Walmsley1, Z. Maan1, A. Zimmermann1, G. Gurtner1, A. Giaccia4, H. P. Lorenz1, S. Ding3, M. Longaker1 1Stanford University,Surgery,Palo Alto, CA, USA 2University Of Hawaii,Surgery,Honolulu, HI, USA 3University Of California – San Francisco,Gladstone Institutes,San Francisco, CA, USA 4Stanford University,Radiation Oncology,Palo Alto, CA, USA
Introduction:
Impaired wound healing, particularly in diabetic and vasculopathic patients, represents a significant clinical challenge. Prior studies have revealed that an important prognostic determinant of wound repair is the presence of hypoxia. Hypoxia-inducible factor (HIF), master regulator of cellular response to hypoxia, is critical for enhancing the appropriate inflammatory and angiogenic responses that promote wound healing. Herein, we examine the effect of small molecule activators of the HIF pathway on wound healing.
Methods:
We generated 25 small molecule analogue inhibitors of PHD2, designated GPHD-1 through GPHD-25. A high throughput HRE-luciferase assay was performed on NIH 3T3 fibroblasts on 96-well plates to identify GPHD compounds that would achieve the greatest increase in the HIF pathway. The best three compounds were tested in vivo using a murine model of wound healing with splinted 6 mm full thickness excisional wounds. The compound was delivered every other day at a concentration of 10 uM. Photographs were taken every other day and the rate of wound healing was analyzed.
Results:
Using the HRE-luciferase assay, we identified compounds GPHD-11, -14, and -15 for upregulating HIF activity 4.01-, 4.38-, and 4.08-fold, respectively (*p<0.05). Full thickness excisional wounds treated with GPHD-11, -14, and -15 completely healed on days 11.5, 11.4, and 11.8, respectively. Wounds treated with saline control healed on day 13.4 (*p<0.05).
Conclusion:
Our results validate the ability of small molecule analogue inhibitors of PHD2 to activate the HIF pathway in vitro. In vivo, we demonstrate accelerated wound healing with topical application of our compounds. With further studies, the small molecule activators of HIF may prove to be a novel therapeutic to stimulate wound healing.