The link between serum uric acid (SUA) and the risk of venous thromboembolism (VTE) is well established. Recent data suggested a causative role of UA in endothelial cells (ECs) dysfunction. However, the molecular mechanism of high UA on thrombogenesis is unknown. We investigate whether high UA induce phosphatidylserine (PS) externalization and microparticle (MP) shedding in cultured EC, and contribute to UA‐induced hypercoagulable state. In the present study, we demonstrate that UA induces PS exposure and EMP release of EC in a concentration‐ and time‐dependent manner, which enhances the procoagulant activity (PCA) of EC and inhibited over 90% by lactadherin in vitro. Furthermore, hyperuricemic rat model was used to evaluate the development of thrombi following by flow stasis in the inferior vena cava (IVC). Hyperuricemia group is more likely to form large and hard thrombi compared with control. Importantly, we found that TMEM16F expression is significantly upregulated in UA‐treated EC, which is crucial for UA‐induced PS exposure and MP formation. Additionally, UA increases the generation of reactive oxygen species (ROS), lipid peroxidation, and cytosolic Ca2+ concentration in EC, which might contribute to increased TMEM16F expression. Using confocal microscopy, we also observed disruption of the actin cytoskeleton, suggesting that depolymerization of actin filaments might be required for TMEM16F activation and followed by PS exposure and membrane blebbing in UA‐treated EC. Our results demonstrate a thrombotic role of EC in hyperuricemia through TMEM16F‐mediated PS exposure and MPs release.

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Although thrombosis event is the leading complication of uremia, its mechanism is largely unknown. The interaction between endothelial cells (ECs) and red blood cells (RBCs) in uremic solutes and its prothrombotic role need to be investigated. Here, we established an in vitro co-incubation model of uremic RBC and EC as well as a uremic rat model induced by adenine. We found increased erythrophagocytosis by EC accompanied with increased reactive oxygen species (ROS), lipid peroxidation and impairment of mitochondrial using flow cytometry, confocal microscopy, and electron microscopy, indicating EC undergo ferroptosis. Further investigations showed increased proteins expression of heme oxygenase-1 (HO-1) and ferritin (FTN) and labile iron pool (LIP) accumulation in EC, which could be suppressed by deferoxamine (DFO). The negative regulators of ferroptosis GPX4 and SLC7A11 were decreased in our erythrophagocytosis model and could be enhanced by ferrostatin-1 (Fer-1) or DFO. In vivo, we observed that vascular EC phagocytosed RBC and underwent ferroptosis in the kidney of the uremic rat, which could be inhibited by blocking the phagocytic pathway or inhibiting of ferroptosis. Next, we found the high tendency of thrombus formation was accompanied by erythrophagocytosis-induced ferroptosis in vitro and in vivo. Importantly, we further revealed that upregulated TMEM16F expression mediated phosphatidylserine externalization on ferroptotic EC, which contributed to a uremia-associated hypercoagulable state. Our results indicate that erythrophagocytosis triggered ferroptosis and followed phosphatidylserine exposure of EC may play a key role in uremic thrombotic complication, which may be a promising target to prevent thrombogenesis of uremia.