Ferroptosis of Endothelial cells Triggered by Erythrophagocytosis Contribute to Thrombogenesis in Uremia

Although thrombosis events is the leading complication of uremia, its mechanism is largely unknown. The interaction between endothelial cell (EC) and red blood cell (RBC) in uremic solutes and its prothrombotic role need to be investigated. We established an in vitro co-incubation model of uremic RBC and EC as well as a uremic rat model induced by adenine to investigate erythrophagocytosis (EP) by EC and its contribution on thrombogenesis in uremia. We found increased EP in EC accompanied by enhanced reactive oxygen species (ROS), lipid peroxidation and impairment of mitochondrial, indicating EC undergo ferroptosis. Further investigations showed that 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 EP model and could be enhanced with the use of Fer-1 or DFO. In vivo, we observed that vascular EC phagocytosed RBC and underwent ferroptosis in kidney of uremic rat, which could be inhibited by blocking phagocytic pathway or inhibition of ferroptosis. Next, we found high tendency of thrombus formation was accompanied with EP induced ferroptosis in vitro and vivo. Importantly, we further revealed that upregulated TMEM16F expression mediated phosphatidylserine (PS) externalization on ferroptotic EC, which contributed to uremia associated hypercoagulable state.<b> </b>EP triggered ferroptosis and followed PS exposure of EC play a key role in uremic thrombotic complication, which may be a promising target to prevent thrombogenesis of uremia.