Hypoxia-induced deregulation of miR-126 and its regulative effect on VEGF and MMP-9 expression

Int J Med Sci. 2013 Dec 10;11(1):17-23. doi: 10.7150/ijms.7329. eCollection 2014.

Abstract

Objective: miR-126, the miRNA considered to be specially expressed in endothelial cells and hematopoietic progenitor cells, is strongly associated with angiogenesis. The purpose is to evaluate the role of miR-126 in hypoxia-induced angiogenesis and the possible mechanisms.

Methods: The expression of miR-126 was detected in hypoxia-treated RF/6A cells and diabetic retinas using real-time PCR. The miR-126 was up- or down-regulated by transfecting miR-126-mimics or inhibitors into RF/6A cells. Cell cycle analysis was performed using flow cytometry. The protein levels of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) were assessed by immunoblotting.

Results: A significantly decreased expression of miR-126 was found in hypoxia-treated RF/6A cells in a time-dependent manner compared with normoxic condition. The expression of miR-126 was also reduced in the retina tissue of streptozotocin-induced diabetic rats. The expression of VEGF and MMP-9 proteins was increased in hypoxia-induced RF/6A cells. In the functional analysis, miR-126-mimic significantly reduced the percentage of RF/6A cells in S phases compared with the negative control under hypoxic conditions. Furthermore, the VEGF and MMP-9 protein levels were sharply decreased in hypoxia-induced RF/6A cells pretreated with miR-126-mimics and increased in the cells pretreated with miR-126-inhibitors.

Conclusions: miR-126 is down-regulated under hypoxic condition both in vitro and in vivo and may halt the hypoxia-induce neovascularization by suspending the cell cycle progression and inhibiting the expression of VEGF and MMP-9.

Keywords: Diabetic retinopathy.; Hypoxia; Matrix metalloproteinase-9; MicroRNA-126; Vascular endothelial growth factor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Cycle / genetics
  • Cell Hypoxia / physiology*
  • Cell Line
  • Choroid / blood supply
  • Choroid / cytology
  • Diabetes Mellitus, Experimental / genetics
  • Diabetes Mellitus, Experimental / metabolism
  • Diabetic Retinopathy / genetics
  • Diabetic Retinopathy / metabolism
  • Diabetic Retinopathy / pathology
  • Endothelial Cells / metabolism*
  • Gene Expression Regulation
  • Male
  • Matrix Metalloproteinase 9 / metabolism*
  • MicroRNAs / antagonists & inhibitors
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Neovascularization, Pathologic / genetics
  • Neovascularization, Pathologic / metabolism
  • Rats
  • Rats, Wistar
  • Retina / cytology
  • Retina / pathology
  • Vascular Endothelial Growth Factor A / metabolism*

Substances

  • MIRN126 microRNA, rat
  • MicroRNAs
  • Vascular Endothelial Growth Factor A
  • Matrix Metalloproteinase 9