Topical prolyl hydroxylase domain-2 silencing improves diabetic murine wound closure

Wound Repair Regen. Jul-Aug 2011;19(4):481-6. doi: 10.1111/j.1524-475X.2011.00697.x. Epub 2011 May 31.

Abstract

Prolyl hydroxylase domain 2 (PHD2) has been implicated in several pathways of cell signaling, most notably in its regulation of hypoxia-inducible factor (HIF)-1α stability. In normoxia, PHD2 hydroxylates proline residues on HIF-1α, rendering it inactive. However, in hypoxia, PHD2 is inactive, HIF-1α is stabilized and downstream effectors such as vascular endothelial growth factor and fibroblast growth factor-2 are produced to promote angiogenesis. In the present study we utilize RNA interference to PHD2 to promote therapeutic angiogenesis in a diabetic wound model, presumably by the stabilization of HIF-1α. Stented wounds were created on the dorsum of diabetic Lepr db/db mice. Mice were treated with PHD2 small interfering RNA (siRNA) or nonsense siRNA. Wounds were measured photometrically on days 0-28. Wounds were harvested for histology, protein, and RNA analysis. Diabetic wounds treated with siRNA closed within 21±1.2 days; sham-treated closed in 28±1.5 days. By day 7, Western blot revealed near complete suppression of PHD protein and corresponding increased HIF-1α. Angiogenic mediators vascular endothelial growth factor and fibroblast growth factor-2 were elevated, corresponding to increased CD31 staining in the treated groups. siRNA-mediated silencing of PHD2 increases HIF-1α and several mediators of angiogenesis. This corresponded to improved time to closure in diabetic wounds compared with sham-treated wounds. These findings suggest that impaired wound healing in diabetes can be ameliorated with therapeutic angiogenesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Diabetes Mellitus / metabolism
  • Disease Models, Animal
  • Fibroblast Growth Factor 2 / genetics
  • Fibroblast Growth Factor 2 / metabolism
  • Gene Silencing*
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism*
  • Hypoxia-Inducible Factor-Proline Dioxygenases
  • Mice
  • Neovascularization, Physiologic
  • Procollagen-Proline Dioxygenase / antagonists & inhibitors*
  • Procollagen-Proline Dioxygenase / genetics
  • RNA, Messenger / metabolism
  • RNA, Small Interfering*
  • Skin / injuries
  • Skin / metabolism
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism
  • Wound Healing*

Substances

  • Hif1a protein, mouse
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • RNA, Messenger
  • RNA, Small Interfering
  • Vascular Endothelial Growth Factor A
  • Fibroblast Growth Factor 2
  • Procollagen-Proline Dioxygenase
  • Egln1 protein, mouse
  • Hypoxia-Inducible Factor-Proline Dioxygenases