title: S1P and the birth of platelets.
abstract: Recent work has highlighted the multitude of biological functions of sphingosine 1-phosphate (S1P), which include roles in hematopoietic cell trafficking, organization of immune organs, vascular development, and neuroinflammation. Indeed, a functional antagonist of S1P(1) receptor, FTY720/Gilenya, has entered the clinic as a novel therapeutic for multiple sclerosis. In this issue of the JEM, Zhang et al. highlight yet another function of this lipid mediator: thrombopoiesis. The S1P(1) receptor is required for the growth of proplatelet strings in the bloodstream and the shedding of platelets into the circulation. Notably, the sharp gradient of S1P between blood and the interstitial fluids seems to be essential to ensure the production of platelets, and S1P appears to cooperate with the CXCL12-CXCR4 axis. Pharmacologic modulation of the S1P(1) receptor altered circulating platelet numbers acutely, suggesting a potential therapeutic strategy for controlling thrombocytopenic states. However, the S1P(4) receptor may also regulate thrombopoiesis during stress-induced accelerated platelet production. This work reveals a novel physiological action of the S1P/S1P(1) duet that could potentially be harnessed for clinical translation.
authors.affiliation: Center for Vascular Biology, Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, Cornell University, New York, NY 10065, USA. tih2002@med.cornell.edu
authors.forename: Timothy
authors.initials: T
authors.lastname: Hla
authors.forename: Sylvain
authors.initials: S
authors.lastname: Galvani
authors.forename: Shahin
authors.initials: S
authors.lastname: Rafii
authors.forename: Ralph
authors.initials: R
authors.lastname: Nachman
mesh_terms: D001792:Blood Platelets / Q000378:metabolism / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D054377:Chemokine CXCL12 / Q000378:metabolism; D045604:Extracellular Fluid / Q000378:metabolism; D008246:Lysophospholipids / Q000097:blood / Q000378:metabolism / Q000502:physiology*; D008954:Models, Biological; D019718:Receptors, CXCR4 / Q000378:metabolism; D049349:Receptors, Lysosphingolipid / Q000378:metabolism*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism / Q000502:physiology; D034061:Thrombopoiesis / Q000502:physiology*
chemical_list: C515255:CXCL12 protein, human; C527276:CXCR4 protein, human; D054377:Chemokine CXCL12; D008246:Lysophospholipids; D019718:Receptors, CXCR4; D049349:Receptors, Lysosphingolipid; C060506:sphingosine 1-phosphate; D013110:Sphingosine