TXA₂/TP

TXA₂/TP signaling is mediated by the thromboxane prostanoid receptor (TP, encoded by TBXA2R), a class A G protein-coupled receptor that serves as the principal receptor for thromboxane A₂ and related prostanoids^[1][2]. TP activation regulates platelet activation, vascular tone, hemostasis, thrombosis, oxidative stress, and inflammatory responses through signaling pathways that control intracellular calcium mobilization, phospholipase C activity, and downstream effector networks^[1][3][4]. Mechanistically, TXA₂ generated during platelet activation binds TP receptors and amplifies platelet aggregation, cytoskeletal remodeling, adhesion, and thrombotic responses, thereby linking eicosanoid metabolism to vascular homeostasis and disease progression^[3][5]. In vascular and inflammatory settings, TP receptors are expressed on platelets, endothelial cells, vascular smooth muscle cells, and monocytes/macrophages, where receptor activation contributes to atherogenesis, vascular constriction, thrombosis, and inflammation^[1]. Disease relevance is supported by experimental models showing that TP receptor deficiency impairs platelet aggregation, prolongs bleeding time, delays atherogenesis, and alters inflammatory responses, highlighting a central role for TP signaling in cardiovascular pathology^[4]. Compared with related prostanoid receptors, TP is unique because it is activated not only by TXA₂ but also by prostaglandin endoperoxides and isoprostanes that accumulate during oxidative stress, extending its functional importance beyond classical thromboxane biology^[1][5]. The human receptor exists as two alternatively spliced isoforms, TPα and TPβ, which differ in their C-terminal domains and exhibit distinct signaling and regulatory properties, providing an important framework for isoform-specific mechanistic studies^[6][7]. For experimental applications, stable TP agonists and selective TP antagonists are widely used to dissect receptor-dependent signaling, platelet function, vascular responses, and disease mechanisms in cardiovascular research^[3][5].