S1PR3

Sphingosine-1-phosphate receptor 3 (S1PR3) is a G protein-coupled receptor that regulates vascular tone and endothelial function^[1]. Mechanistically, S1PR3 activation stimulates intracellular PI3K/Akt and ERK1/2 signaling, promoting extracellular matrix synthesis and vascular remodeling independent of Smad pathways^[1]. In physiological models, S1PR3 contributes to blood pressure homeostasis and flow-mediated mechanotransduction, complementing S1PR1-mediated nitric oxide signaling^[2][1]. Compared with S1PR1 and S1PR2, S1PR3 exhibits distinct pro-fibrotic potential and unique signaling bias, influencing fibroblast and endothelial responses differently^[1][3]. In disease models, S1PR3 involvement has been implicated in pulmonary fibrosis and inflammatory vascular injury, where agonist-mediated activation enhances extracellular matrix deposition and endothelial remodeling^[1]. Selective agonists and antagonists have been used to dissect S1PR3-specific effects, demonstrating that dual S1PR1/S1PR3 agonists amplify fibrotic signaling, whereas S1PR3-sparing modulators reduce off-target vascular responses^[1][4]. For experimental applications, these pharmacological tools allow precise modulation of fibroblast differentiation, vascular remodeling, and inflammation, facilitating the development of targeted therapies without interfering with closely related isoforms^[1][4][3]. Collectively, S1PR3 represents a functionally distinct S1P receptor with critical roles in cardiovascular physiology, fibrosis, and experimental modeling of vascular and pulmonary disease.