Genetic deficiency and pharmacological modulation of RORα regulate laser-induced choroidal neovascularization

Abstract

Choroidal neovascularization (CNV) causes acute vision loss in neovascular age-related macular degeneration (AMD). Genetic variations of the nuclear receptor RAR-related orphan receptor alpha (RORα) have been linked with neovascular AMD, yet its specific role in pathological CNV development is not entirely clear. In this study, we showed that Rora was highly expressed in the mouse choroid compared with the retina, and genetic loss of RORα in Staggerer mice (Rora sg/sg ) led to increased expression levels of Vegfr2 and Tnfa in the choroid and retinal pigment epithelium (RPE) complex. In a mouse model of laser-induced CNV, RORα expression was highly increased in the choroidal/RPE complex post-laser, and loss of RORα in Rora sg/sg eyes significantly worsened CNV with increased lesion size and vascular leakage, associated with increased levels of VEGFR2 and TNFα proteins. Pharmacological inhibition of RORα also worsened CNV. In addition, both genetic deficiency and inhibition of RORα substantially increased vascular growth in isolated mouse choroidal explants ex vivo. RORα inhibition also promoted angiogenic function of human choroidal endothelial cell culture. Together, our results suggest that RORα negatively regulates pathological CNV development in part by modulating angiogenic response of the choroidal endothelium and inflammatory environment in the choroid/RPE complex.

Retinoic acid related orphan receptor α is a genetic modifier that rescues retinal degeneration in a mouse model of Stargardt disease and Dry AMD

“…Nuclear hormone receptors regulate numerous retinal homeostatic pathways. In particular, RORA is implicated in AMD and is a key regulator of pathways perturbed in AMD disease, such as the complement system including complement C3 and C5 that are targets of recent FDA-approved drugs for dry AMD [27,28,46,47]. In this study we test the potential of three different doses of AAV5-hRORA as a modifier gene therapy to treat macular degeneration in Abca4 −/− mice, as it is a model for both early onset STGD and late onset dry AMD, and exhibits subretinal deposits and reduced retinal function, as well as perturbation of complement genes [22,33,34,37,64,65].…”

“…The molecular phenotype in Abca4 −/− mice, including reduced CD59 and RORA expression, presents much earlier than and likely leads to the clinical phenotype [22,37]. Downregulated RORA expression in Abca4 −/− mice impacts the pathways required for retinal function and homeostasis, leading to vision loss [2,46,47,76]. The impact of these studies is that treatment with RORA before manifestation of the clinical phenotype potentially resets RORA-regulated pathways, including the inflammatory response pathway by restoring CD59 expression, thereby preventing disease.…”

“…Molecular rescue of the inflammatory response in AAV5-hRORA-treated Abca4 −/− retinas RORA regulates the inflammatory response pathway that includes complement pathway genes and is implicated in both the STGD and dry AMD-like phenotypes [34][35][36][37]47]. In particular, CD59, an inhibitor of the MAC, is downregulated in both diseases and is part of the RORA-regulated inflammatory response pathway that also includes ABCA4 [33,36,37].…”

“…Retinoic acid related orphan receptor α (RORA) is a nuclear hormone receptor (NHR) that regulates several homeostatic pathways in the retina including the lipid metabolism, oxidative stress and inflammation pathways [46][47][48]. Prior results demonstrated that RORA is linked with AMD and is a known regulator of multiple AMD genes [2,48,49].…”

Ectopic Rod Photoreceptor Development in Mice with Genetic Deficiency of WNT2B

“…RT-qPCR experiments were carried out based on previous protocols [ 25 ]. Tissue samples from Wnt2b mice were first homogenized and lysed using QIAzol Lysis Reagent (Qiagen, Germantown, MD, USA, Cat#: 79306).…”