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S.J. Reich, J. Fosnot, S. Wan, I.–H. Wu, M.J. Tolentino; Choroidal neovascularization is inhibited by HIF1–alpha siRNA in a mouse model . Invest. Ophthalmol. Vis. Sci. 2004;45(13):2232.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Previous studies have shown the ability to decrease both vascular endothelial growth factor (VEGF) protein levels and choroidal neovascularization using small interfering RNA (siRNA) specific for VEGF. The purpose of this study was to evaluate the ability of siRNA targeted against human hypoxia inducible factor 1 alpha (HIF1–alpha) to decrease choroidal neovascularization in an in vivo murine model. Methods:Human HIF1–alpha siRNA was transfected into human 293 cells followed by chemically induced hypoxia leading to the upregulation of VEGF protein. VEGF protein levels were quantified using ELISA twenty–four hours following the induction of hypoxia. In addition, mice were lasered to induce neovascularization followed by intravitreal injection of either siRNA specific for murine HIF1–alpha or control (a non–specific siRNA). The mice were perfused using fluoroscein, sacrificed, choroidal flat mounts were made and the neovascular areas were then quantified. Results:VEGF upregulation occurred in both hypoxic cells without siRNA and hypoxic cells with a non–specific siRNA. In the presence of HIF1–alpha siRNA there was no difference in the VEGF levels as compared to controls without hypoxia. Human HIF1–alpha siRNA disrupted hypoxic signaling leading to VEGF upregulation in a dose–dependent fashion. Murine siRNA specific for HIF1–alpha successfully decreased neovascular area in the laser induced model of choroidal neovascularization. Conclusions: In human cells, HIF1–alpha is necessary for chemical induced hypoxic signaling of VEGF upregulation. In the laser induced model of choroidal neovascularization HIF1–alpha is involved in the signaling events following the rupture of Bruch’s membrane by laser leading to choroidal neovascularization. These results suggest that HIF1–alpha may be a relevant therapeutic target in patients with wet age–related macular degeneration, and support the potential for the use of siRNA targeting HIF1–alpha as a therapeutic strategy for this disease.
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