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

Abstract

ABSTRACT 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.