摘要Retinopathy of prematurity(ROP)is a vision-threatening disorder that leads to pathological growth of the retinal vasculature due to hypoxia.Here,we investigated the potential effects of alamandine,a novel heptapeptide in the renin-angiotensin system(RAS),on hypoxia-induced retinal neovascularization and its underlying mechanisms.In vivo,the C57BL/6J mice with oxygen-induced retinopathy(OIR)were injected intravitreally with alamandine(1.0 μmol/kg per eye).In vitro,human retinal microvascular endothelial cells(HRMECs)were utilized to investigate the effects of alamandine(10 μg/mL)on proliferation,apoptosis,migration,and tubular formation under vascular endothelial growth factor(VEGF)stimulation.Single-cell RNA sequencing(scRNA-seq)matrix data from the Gene Expression Omnibus(GEO)database and RAS-related genes from the Molecular Signatures Database(MSigDB)were sourced for subsequent analyses.By integrating scRNA-seq data across multiple species,we identified that RAS-associated endothelial cell populations were highly related to retinal neovascularization.The liquid chromatography-tandem mass spectrometry(LC-MS/MS)analysis revealed a significant decrease in alamandine levels in both the serum and retina of OIR mice compared to those in the control group.Next,alamandine ameliorated hypoxia-induced retinal pathological neovascularization and physiologic revascularization in OIR mice.In vitro,alamandine effectively mitigated VEGF-induced proliferation,scratch wound healing,and tube formation of HRMECs primarily by inhibiting the hypoxia-inducible factor-1α(HIF-1α)/VEGF pathway.Further,coincubation with D-Pro7(Mas-related G protein-coupled receptor D(MrgD)antagonist)hindered the beneficial impacts of alamandine on hypoxia-induced pathological angiogenesis both in vivo and in vitro.Our findings suggested that alamandine could mitigate retinal neovascularization by targeting the MrgD-mediated HIF-1α/VEGF pathway,providing a potential therapeutic agent for OIR prevention and treatment.