title: Inhibition of hypoxia-induced retinal neovascularization in mice with short hairpin RNA targeting Rac1, possibly via blockading redox signaling.
abstract: NADPH oxidase-derived reactive oxygen species are involved in angiogenesis in vitro and regulated by ras-related C3 botulinum toxin substrate 1 (Rac1). This study has employed vector-based short hairpin RNA targeting Rac1 (Rac1-shRNA) to investigate the inhibitory effect on hypoxia-induced retinal neovascularization (RN) in vivo and the underlying mechanism. pSUPER-Rac1-shRNA was intravitreally injected into the mouse model of oxygen-induced retinopathy. RN was evaluated by FITC-dextran angiography and quantitated histologically. Expressions of Rac1, nuclear factor kappa B (NF-κB) subunit p65, hypoxia-inducible factor-1 alpha (HIF-1α), and vascular endothelial growth factor (VEGF) were determined by real-time quantitative RT-PCR and western blotting. After intravitreal administration of pSUPER-Rac1-shRNA, retinal Rac1 gene expression was reduced by 72% at postnatal day 17 (P17). Retinal flat mount and quantification of the neovascular nuclei demonstrated that RN was significantly inhibited. Meanwhile, the expression levels of NF-κB and HIF-1α, the redox-dependent transcription factors, were significantly downregulated. HIF-1α and its downstream gene VEGF were found to be significantly decreased at both transcriptional and translational levels. Our findings not only suggest that Rac1 may be involved in the process of RN in mouse oxygen-induced retinopathy via regulating the redox signaling, but may also provide a novel therapeutic target for hypoxia-induced retinal neovascular diseases.
authors.affiliation: Department of Ophthalmology, West China Hospital, Sichuan University, 37 Guoxuexiang, Chengdu, Sichuan Province 610041, China.
authors.forename: Xiong-Ze
authors.initials: XZ
authors.lastname: Zhang
authors.forename: Xi
authors.initials: X
authors.lastname: Huang
authors.forename: Ji-Hong
authors.initials: JH
authors.lastname: Qiao
authors.forename: Jun-Jun
authors.initials: JJ
authors.lastname: Zhang
authors.forename: Mei-Xia
authors.initials: MX
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D003911:Dextrans; D004195:Disease Models, Animal; D005451:Fluorescein Angiography; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D000860:Hypoxia / Q000150:complications*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics; D058449:Intravitreal Injections; D051379:Mice; D008810:Mice, Inbred C57BL; D009479:Neuropeptides / Q000235:genetics*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000633:toxicity; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000494:pharmacology*; D015861:Retinal Neovascularization / Q000209:etiology / Q000235:genetics / Q000517:prevention & control*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D051996:Transcription Factor RelA / Q000235:genetics; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics; D020744:rac GTP-Binding Proteins / Q000235:genetics*; D020830:rac1 GTP-Binding Protein
chemical_list: D003911:Dextrans; C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009479:Neuropeptides; D034741:RNA, Small Interfering; C484602:Rac1 protein, mouse; D051996:Transcription Factor RelA; D042461:Vascular Endothelial Growth Factor A; C015219:fluorescein isothiocyanate dextran; C467480:vascular endothelial growth factor A, mouse; D020744:rac GTP-Binding Proteins; D020830:rac1 GTP-Binding Protein; D016650:Fluorescein-5-isothiocyanate; D010100:Oxygen