Therapeutic influence of ACKR3/CXCR7 in inducing Anticoagulant Acylcarnitines: implications for Deep Vein Thrombosis and Coronary Artery Disease

Introduction Pharmacological targeting of the chemokine receptor ACKR3/CXCR7 regulates arterial thrombosis, platelet reactivity and thrombo-inflammatory response following myocardial infarction, those induced by immunothrombotic IgGs, and in coronary artery disease (CAD) patients ex vivo. CXCR7 agonist triggers the generation of anti-platelet lipid 12-HETrE which ligates the prostacyclin receptor and induces the platelet inhibitory cAMP dependent signaling cascade. Current investigation explores the antithrombotic and anticoagulatory implications of targeting CXCR7.

Method Stasis model of DVT in mice;platelet degranulation, integrin activation, procoagulant response, platelet-leukocyte aggregate formation in DVT model by flow cytometry; lipidomics analysis by UHPLC-QTOF-MS/MS; metabolomics analysis by HILIC-QTOF-MS; platelet mitochondrial respiration using Seahorse platform; calibrated automated thrombinography; phosphorylation of adenosine monophosphate-dependent kinase (AMPK^Ser-172) and acetyl-CoA carboxylase (ACC^Ser-79) by immunoblot analysis.

Results Administration of CXCR7-agonist (VUF11207) significantly decreased thrombus burden in the inferior vena cava of DVT mice 48hrs post stasis; it reduced circulatory platelet degranulation (CD62P), α_IIbβ₃-integrin activation (JON/A), thrombogenic phosphatidylserine exposure on procoagulant platelets and thrombo-inflammatory platelet-leukocyte aggregate formation. VUF11207 administration also retarded subsequent enhancement in such functional responses to collagen related peptide ex vivo. Long-chain Acylcarnitines (LC-ACars) exert anticoagulant influence by inhibiting Factor-Xa, circulatory levels of which are reduced in venous thromboembolism (VTE) and STEMI patients potentially accounting for their thrombotic disposition. VUF11207 induced the generation of LC-ACars in platelets from healthy subjects and CAD patients ex vivo, and prompted their release in the external milieu. Lipidomics and metabolomics profiling of resting and thrombin activated platelets revealed significantly elevated levels of LC- ACars (16:0, 18:1, 18:2), without affecting mitochondrial respiration, anabolic utilization of glucose, amino acid, lipids, also platelet energetic status, assessed by ATP measurements and adenylate energy charge. CXCR7 ligation caused activation of AMPK^Ser-172, and subsequently AMPK-mediated phosphorylation and thereby inhibition of ACC^Ser-79, thus fostering lipolysis over de novo lipogenesis, which could contribute to LC-ACar generation. Inhibitory effect of VUF11207 on platelet dependent thrombin generation was partially counteracted by carnitine palmitoyltransferase-1 inhibitor etomoxir that prevents LC-ACar formation, suggesting its anticoagulatory potential.

Conclusion Therapeutic targeting of CXCR7 may modulate thrombotic and procoagulatory response in DVT and CAD. Validation of CXCR7-agonist induced LC-ACar as an anticoagulant mediator will be made in future clinical investigations.