Overexpression of hypoxia-inducible factor prolyl hydoxylase-2 attenuates hypoxia-induced vascular endothelial growth factor expression in luteal cells

Mol Med Rep. 2015 Sep;12(3):3809-3814. doi: 10.3892/mmr.2015.3788. Epub 2015 May 14.

Abstract

Vascular endothelial growth factor (VEGF)-dependent angiogenesis has a crucial role in the corpus luteum formation and their functional maintenances in mammalian ovaries. A previous study by our group reported that activation of hypoxia‑inducible factor (HIF)‑1α signaling contributes to the regulation of VEGF expression in the luteal cells (LCs) in response to hypoxia and human chorionic gonadotropin. The present study was designed to test the hypothesis that HIF prolyl‑hydroxylases (PHDs) are expressed in LCs and overexpression of PHD2 attenuates the expression of VEGF induced by hypoxia in LCs. PHD2-overexpressing plasmid was transfected into LC2 cells, and successful plasmid transfection and expression was confirmed by reverse transcription quantitative polymerase chain reaction and western blot analysis. In addition, the present study investigated changes of HIF‑1α and VEGF expression after incubation under hypoxic conditions and PHD2 transfection. PHD2 expression was significantly higher expressed than the other two PHD isoforms, indicating its major role in LCs. Moreover, a significant increase of VEGF mRNA expression was identified after incubation under hypoxic conditions, which was, however, attenuated by PHD2 overexpression in LCs. Further analysis also indicated that this hypoxia‑induced increase in the mRNA expression of VEGF was consistent with increases in the protein levels of HIF‑1α, which is regulated by PHD-mediated degradation. In conclusion, the results of the present study indicated that PHD2 is the main PHD expressed in LCs and hypoxia‑induced VEGF expression can be attenuated by PHD2 overexpression through HIF‑1α‑mediated mechanisms in LCs. This PHD2-mediated transcriptional activation may be one of the mechanisms regulating VEGF expression in LCs during mammalian corpus luteum development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Hypoxia
  • Cells, Cultured
  • Female
  • Gene Expression
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
  • Hypoxia-Inducible Factor-Proline Dioxygenases
  • Luteal Cells / metabolism*
  • Procollagen-Proline Dioxygenase / genetics
  • Procollagen-Proline Dioxygenase / metabolism*
  • Rats, Sprague-Dawley
  • Transcriptional Activation
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism*

Substances

  • Hif1a protein, rat
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Vascular Endothelial Growth Factor A
  • vascular endothelial growth factor A, rat
  • Procollagen-Proline Dioxygenase
  • Egln1 protein, rat
  • Hypoxia-Inducible Factor-Proline Dioxygenases