Purchase this article with an account.
J. Chen, K. M. Connor, C. M. Aderman, K. L. Willett, O. P. Aspegren, R. J. Dennison, N. M. Krah, L. E. Smith; Erythropoietin siRNA Prevents Proliferative Retinopathy in Mice. Invest. Ophthalmol. Vis. Sci. 2009;50(13):5692.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Proliferative retinal vascular growth is the leading cause of blindness in the US population. Retinopathy could be suppressed by preventing initial vessel loss and thereby reducing tissue hypoxia that stimulates neovascularization, or by direct inhibition of neovascularization. Erythropoietin (Epo), an oxygen-regulated growth hormone with a known function of stimulating erythrocyte production, is a growth factor critical for retinal angiogenesis. Our previous studies found that supplementation of recombinant Epo early in retinopathy, when endogenous expression of Epo is suppressed, prevents the initial retina vessel loss and subsequent neovascularization in mice. In this study, we investigated direct suppression of retinal neovascularization in the late neovascular phase through inhibition of Epo with RNA interference.
Proliferative retinopathy is modeled in mice by exposing neonatal mice to 75% oxygen from P7 to P12, followed by room air. Retinal Epo and Epo receptor mRNA expression were quantified with real time RT-PCR in whole retina and on laser-captured retinal vessels and neuronal layers. Retinal hypoxia was assessed with an oxygen-sensitive hypoxyprobe. A small interference RNA (siRNA) targeting Epo or control negative siRNA was injected intravitreally to fellow eyes of mice at P12, P14 and P15 during the hypoxic phase of retinopathy and the effect on neovascularization was evaluated in retinal flatmounts at P17.
Epo mRNA expression was significantly elevated during the second proliferative phase of retinopathy, both in whole retina as found previously, and on three laser-microdissected retinal neuronal layers. The increase of Epo corresponded to an increased level of tissue hypoxia found in vaso-obliterated area of retina. Epo receptor mRNA expression levels also increased during retinopathy development, specifically in hypoxia-induced neovascular vessels. Epo siRNA successfully inhibited ~60% of retinal Epo mRNA expression and significantly inhibited about half of pathologic retinal neovascularization at P17.
Inhibiting Epo mRNA expression with siRNA is effective in suppressing retinal neovascularization, suggesting that Epo siRNA might be a potentially useful pharmaceutical intervention for treating proliferative retinopathy.
This PDF is available to Subscribers Only