Adeno-associated viral vector-mediated hypoxia-regulated VEGF gene transfer promotes angiogenesis following focal cerebral ischemia in mice

Gene Ther. 2008 Jan;15(1):30-9. doi: 10.1038/ Epub 2007 Oct 25.


Uncontrolled expression of vascular endothelial growth factor (VEGF) in vivo may cause unexpected side effects, such as brain hemangioma or tumor growth. Because hypoxia-inducible factor-1 (HIF-1) is upregulated during cerebral ischemia and regulates gene expression by binding to a cis-acting hypoxia-responsive element (HRE), we therefore used a novel HRE, originating in the 3'-end of the erythropoietin (Epo) gene, to control gene expression in the ischemic brain. A concatemer of nine copies (H9) of the consensus sequence of HRE was used to mediate hypoxia induction. Three groups of adult CD-1 mice received AAVH9-VEGF, AAVH9-lacZ or saline injection, and then underwent 45 min of transient middle cerebral artery occlusion (tMCAO). Results show that HIF-1 was persistently expressed in the ischemic brain. VEGF was overexpressed in the ischemic perifocal region in AAVH9-VEGF-transduced mice. Double-labeled immunostaining showed that VEGF expressed in neurons and astrocytes but not endothelial cells, suggesting that adeno-associated virus (AAV) vectors transduced neurons and astrocytes predominantly. The total number of microvessels/enlarged microvessels was greatly increased in the AAVH9-VEGF-transduced mice (180+/-29/27+/-4) compared to the AAVH9-lacZ (118+/-19/14+/-3) or saline-treated (119+/-20/14+/-2) mice after tMCAO (P<0.05). Cell proliferation examination demonstrated that these microvessels were newly formed. Regional cerebral blood flow recovery in the AAVH9-VEGF-transduced mice was also better than in AAVH9-lacZ or saline-treated mice (P<0.05). Our data indicated that HRE is a novel trigger for the control of VEGF expression in the ischemic brain. VEGF overexpression through AAVH9-VEGF gene transfer showed stable focal angiogenic effects in post-ischemic repair process, providing an opportunity to rebuild injured brain tissue.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 3' Untranslated Regions
  • Animals
  • Astrocytes / chemistry
  • Brain Ischemia / metabolism
  • Brain Ischemia / physiopathology
  • Brain Ischemia / therapy*
  • Cerebrovascular Circulation
  • Dependovirus / genetics*
  • Erythropoietin / genetics
  • Gene Expression
  • Genetic Therapy / methods*
  • Genetic Vectors / administration & dosage*
  • Hypoxia / metabolism
  • Hypoxia-Inducible Factor 1 / analysis
  • Hypoxia-Inducible Factor 1 / genetics
  • Immunohistochemistry
  • Mice
  • Neovascularization, Physiologic
  • Neurons / chemistry
  • Transduction, Genetic / methods*
  • Vascular Endothelial Growth Factor A / analysis
  • Vascular Endothelial Growth Factor A / genetics*


  • 3' Untranslated Regions
  • Hypoxia-Inducible Factor 1
  • Vascular Endothelial Growth Factor A
  • Erythropoietin