Caveola and Its Resident Proteins, Caveolin-1 and -2, Play Critical Roles in the Pathogenesis of nAMD and PCV.

The purpose of this study was to investigate cellular and molecular mechanisms underlying neovascular age-related macular degeneration (nAMD) and polypoidal choroidal vasculopathy (PCV) via single-cell RNA sequencing (scRNA-seq), then focusing on caveolae-resident proteins based on identified negatively enriched caveolae via Gene Set Enrichment Analysis (GSEA). Peripheral blood mononuclear cells (PBMCs) from patients with nAMD/PCV (n = 10) and healthy controls (n = 9) were collected. A total of 22,593 high-quality monocytes were analyzed for differentially expressed genes (DEGs) and GSEA. The key finding of negatively enriched caveola was recapitulated by in vitro mRNA transfections in THP-1 monocytes and human umbilical vein endothelial cells (HUVECs), followed by validation using qPCR. Functional assays and cytokine profiling were also performed. A total of 122 significant pathways was identified from WikiPathways, Reactome, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Ontology. GSEA revealed significant negative enrichment of caveola in classical monocytes of PCV (NES = -1.769, P = 0.001, q = 0.026). Cytokine/chemokine profiling revealed that Caveolin (CAV)1/2-overexpressing monocytes secreted markedly higher levels of several proinflammatory mediators, including IL-1β, IL-2, IL-8, IL-17, TNF-α, PDGF-BB, and MIP-1α/β. CAV1 or CAV2 overexpression in THP-1 cells increased monocyte adhesion but inhibited transendothelial migration. In HUVECs, their overexpression induced moderate cytokine profiles, including downregulation of RANTES (CCL5), IL-10, and VEGF, and upregulation of IL-6 and MIP-1α. CAV1/2 overexpression also significantly inhibited tube formation, whereas knockdown of CAV1 or CAV2 enhanced tube formation. Caveolins appear to contribute to the pathogenesis of nAMD and PCV as modulators of inflammation and vascular function. Enhanced CAV1/2 expression in endothelial cells attenuates angiogenic activity, indicating a potential therapeutic strategy.