Molecular regulation of coagulation by heparin-bound plasma Latexin

Latexin (LXN), a naturally occurring low-molecular-weight protein, plays crucial roles in coagulation, inflammation, and thrombosis, making it highly relevant to hematological and cardiovascular research. In this study, we investigated the physiological function of LXN in coronary artery disease (CAD), with a particular focus on its heparin-dependent regulation of the coagulation process. Clinical evaluations showed that plasma LXN concentrations are significantly varied among patients with chronic coronary syndrome (CCS) versus acute coronary syndrome (ACS), which indicates its possible diagnostic and prognostic value. The animal experiments also showed that LXN deficiency significantly increases the time of bleeding and clotting, which suggests that LXN directly contributes to the formation of thrombus. Molecular docking and molecular dynamics simulations showed strong heparin-binding capacity (docking score: -5.923; binding energy: -78.512 kJ/mol), while circular dichroism spectroscopy confirmed that LXN-heparin complex formation induces conformational changes and enhances procoagulant activity. Together, these findings demonstrate that plasma LXN serves not only as a promising biomarker for CAD, particularly ACS, but also that LXN can competitively bind to heparin, reducing its interaction with AT-III and thereby diminishing heparin's anticoagulant effect, acting as a physiological regulator of the coagulation process. LXN, therefore, represents a potential new molecular target for early diagnosis and therapeutic intervention in CAD.