title: Adeno-associated viral vector-mediated hypoxia-regulated VEGF gene transfer promotes angiogenesis following focal cerebral ischemia in mice.
abstract: 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.
authors.affiliation: Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, CA 94110, USA.
authors.forename: F
authors.initials: F
authors.lastname: Shen
authors.forename: Y
authors.initials: Y
authors.lastname: Fan
authors.forename: H
authors.initials: H
authors.lastname: Su
authors.forename: Y
authors.initials: Y
authors.lastname: Zhu
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: W
authors.initials: W
authors.lastname: Liu
authors.forename: W L
authors.initials: WL
authors.lastname: Young
authors.forename: G-Y
authors.initials: GY
authors.lastname: Yang
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D001253:Astrocytes / Q000737:chemistry; D002545:Brain Ischemia / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D002560:Cerebrovascular Circulation; D000229:Dependovirus / Q000235:genetics*; D004921:Erythropoietin / Q000235:genetics; D015870:Gene Expression; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000008:administration & dosage*; D000860:Hypoxia / Q000378:metabolism; D051793:Hypoxia-Inducible Factor 1 / Q000032:analysis / Q000235:genetics; D007150:Immunohistochemistry; D051379:Mice; D018919:Neovascularization, Physiologic; D009474:Neurons / Q000737:chemistry; D014161:Transduction, Genetic / Q000379:methods*; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis / Q000235:genetics*
chemical_list: D020413:3' Untranslated Regions; D051793:Hypoxia-Inducible Factor 1; D042461:Vascular Endothelial Growth Factor A; D004921:Erythropoietin