ErpY-like Protein Interaction with Host Thrombin and\nFibrinogen Intervenes the Plasma Coagulation through Extrinsic and\nIntrinsic Pathways

The\nsurvival and proliferation of pathogenic <i>Leptospira</i> within a host are complex phenomena that require careful consideration.\nThe ErpY-like lipoprotein, found on the outer membrane surface of <i>Leptospira</i>, plays a crucial role in enhancing the bacterium’s\npathogenicity. The rErpY-like protein, in its recombinant form, contributes\nsignificantly to spirochete virulence by interacting with various\nhost factors, including host complement regulators. This interaction\nfacilitates the bacterium’s evasion of the host complement\nsystem, thereby augmenting its overall pathogenicity. The rErpY-like\nprotein exhibits a robust binding affinity to soluble fibrinogen,\na vital component of the host coagulation system. In this study, we\ndemonstrate that the rErpY-like protein intervenes in the clotting\nprocess of the platelet-poor citrated plasma of bovines and humans\nin a concentration-dependent manner. It significantly reduces clot\ndensity, alters the viscoelastic properties of the clot, and diminishes\nthe average clotting rate in plasma. Furthermore, the ErpY-like protein\ninhibits thrombin-catalyzed fibrin formation in a dose-dependent manner\nand exhibits saturable binding to thrombin, suggesting its significant\nrole in leptospiral infection. These findings provide compelling evidence\nfor the anticoagulant effect of the ErpY-like lipoprotein and its\nsignificant role in leptospiral infection.