Figure 2.

Prostaglandin Signaling Regulates Vascular Tone in PAH Progression

PGI₂, PGD₂, and PGE₂ relax smooth muscle cells (SMCs) through IP, PGD₂ receptor 1, and EP2 and EP4 receptors, respectively. PGE₂ constricts blood vessels through EP1 and EP3. PGD₂ promotes inflammation and PAH through CRTH2 of T helper type 2 (Th2) cells. AA = arachidonic acid; AC = adenylate cyclase; cAMP = adenosine cyclic phosphate; COX1/2 = cyclooxygenase 1/2; EC = endothelial cell; IL = interleukin; IP₃ = inositol triphosphate; PGDS = prostaglandin D synthase; PGES = prostaglandin E synthase; PGFS = prostaglandin F synthase; PGIS = prostaglandin I synthase; PL = phospholipase; ROS = reactive oxygen species; TxAS = thromboxane synthase; VEGF = vascular endothelial growth factor; other abbreviations as in Figure 1.