HO-1-mediated ferroptosis regulates retinal neovascularization via the COX2/VEGFA axis

Retinal neovascularization (RNV) is a key pathological process in many blinding disorders. This study aims to investigate the potential mechanisms of heme oxygenase-1 (HO-1) on ferroptosis during RNV. Through bioinformatics analysis, differentially expressed ferroptosis-related genes were identified in the oxygen-induced retinopathy (OIR) mouse model. Ferroptosis was assessed in the OIR model and the human retinal microvascular endothelial cells (HRECs) with the treatment of H₂O₂. The mRNA and protein levels were measured through RT-qPCR and western blot. Lipid peroxidation was assessed through C11-BODIPY staining. HO-1 expression was knocked down by intravitreal injection with a self-complementary adeno-associated virus in the OIR model and small interfering RNA in HRECs. The pathological neovascular area and avascular area were assessed through immunofluorescent staining. The cellular functions of HRECs were evaluated with migration and tube formation assays. Our results demonstrated that HO-1 was significantly upregulated in the OIR model. 4-HNE upregulation and GPX4 downregulation were observed in the OIR model. The H₂O₂-induced oxidative stress resulted in lipid peroxidation, GPX4 downregulation, and mitochondrial morphology changes in HRECs. HO-1 knockdown induced GPX4 upregulation, and decreased lipid peroxidation in vitro and in vivo. Furthermore, HO-1 inhibition reduced pathological RNV in the OIR model and attenuated migration and tube formation in HRECs. Treatment with 6-OHDA restored the decrease of VEGFA, migration, and tube formation caused by HO-1 knockdown in HRECs. Overall, HO-1-mediated ferroptosis can regulate RNV through the COX2/VEGFA signal axis. These findings suggest that targeting HO-1 may serve as a promising approach for treating retinal neovascular diseases.