Microglial TSPAN4-Dependent Migrasomes Promote Pathological Retinal Neovascularization via Immune-Vascular Crosstalk.

Diabetic retinopathy (DR) is a leading cause of vision loss among working-age adults worldwide, yet the microglial mechanisms driving pathological retinal neovascularization (RNV) remain incompletely understood. By integrating single-cell transcriptomic profiling of human fibrovascular membranes with murine disease models, we identified a TSPAN4-associated microglial state characterized by a pro-angiogenic and activated transcriptional program. Spatially, TSPAN4-expressing microglia accumulated around pathological vascular tufts, and suppression of TSPAN4 attenuated RNV in the oxygen-induced retinopathy (OIR) model. Under high-glucose and hypoxic conditions, microglia upregulated TSPAN4 expression and triggered the biogenesis of migrasomes along retraction fibers. Microglia-derived migrasomes were sufficient to promote endothelial angiogenic responses in vitro and pathological neovascularization in vivo. Mechanistically, transcriptomic analyses revealed that microglial migrasomes exerted pro-angiogenic effects by activating the HIF-1α/VEGF pathway in endothelial cells. In parallel, migrasomes reinforced a pro-inflammatory microglial phenotype, establishing a pathogenic feed-forward loop that amplified retinal vascular injury. Collectively, our findings define TSPAN4-dependent migrasome formation as a critical mechanism through which microglia promote pathological RNV and uncover migrasome-mediated communication as a previously unrecognized mode of immune-vascular crosstalk. Targeting the microglial TSPAN4-migrasome axis represents a promising therapeutic strategy for neovascular retinal diseases.