Targeting ACKR3/CXCR7 Enhances Platelet Anticoagulant Acylcarnitines and Modulates Procoagulant Function

Abstract

Targeting ACKR3/CXCR7 regulates enzymatic generation of pro-thrombotic, while favoring anti-thrombotic lipids that inhibit platelets through AC-cAMP-PKA pathway in coordination with prostacyclin-IP receptor. This investigation validated the impact of CXCR7 in modulating non-enzymatic lipid (per)oxidation, platelet response to lipoproteins-(LDL, oxLDL), mitochondrial metabolism and procoagulatory functions. Pharmacological CXCR7-agonist-(VUF11207) preserved mitochondrial membrane integrity-(Δψm), counteracted activation-induced mitochondrial superoxide generation-(MitoSOXRed), and nonenzymatic lipid (per)oxidation. Additionally, CXCR7-agonist regulated lipoprotein-induced platelet adhesion on thrombogenic matrices, degranulation, αIIbβIII-integrin activation, aggregation and thrombotic response, by reducing lipoprotein uptake through scavenger receptors-(CD36, ApoER2). CXCR7-ligation triggered activation of metabolic energy sensor Adenosine MonoPhosphate-dependent Kinase-(AMPKSer-172), prompted AMPK-mediated inhibitory phosphorylation of Acetyl-CoA-Carboxylase-(ACC)Ser-79, to foster lipolysis over lipogenesis. Consequently AMPKSer-172-ACCSer-79 pathway increased anticoagulatory FXa-inhibitory long-chain acylcarnitine-(LC-CARs)-(16:0, 18:1, 18:2) generation in platelets from healthy subjects and CAD patients. Increased intraplatelet LC-CARs was not due to dysregulated mitochondrial respiration; since CXCR7-agonist improved maximal respiration, spare respiratory capacity, and ATP-linked respiration in thrombin-activated platelets, suggesting sustained mitochondrial metabolism. Exerting a two-pronged effect on procoagulant function, CXCR7-agonist downregulated phosphatidylserine exposure on activated platelets, reducing FX/FXa binding, while platelet-derived anticoagulatory-LC-CARs regulated thrombin generation. CXCR7-agonist administration reduced thrombus formation, platelet degranulation, αIIbβIII-integrin activation, procoagulant activity, circulatory platelet-leukocyte aggregates in murine venous thrombosis model; besides, decreased plasma procoagulant lipids-(platelet COX-1, 12-LOX, and leukocyte 5/15-LOX-derived) and thrombo-inflammatory mediators-(IL-1β, IL-6, IFN-γ, TNF-α, MCP-1), and increased plasma LC-CAR levels. Therefore, pharmacological targeting of CXCR7 could regulate (non)enzymatic lipid processing, and promote anticoagulatory LC-CAR generation to check platelet-directed thrombotic propensity, and hypercoagulation, moreover, replenish reduced levels of circulatory anticoagulant-LC-CARs in STEMI and venous thromboembolism-(VTE) patients.