title: Selective coupling of the S1P3receptor subtype to S1P-mediated RhoA activation and cardioprotection.
abstract: Sphingosine-1-phosphate (S1P), a bioactive lysophospholipid, is generated and released at sites of tissue injury in the heart and can act on S1P1, S1P2, and S1P3receptor subtypes to affect cardiovascular responses. We established that S1P causes little phosphoinositide hydrolysis and does not induce hypertrophy indicating that it does not cause receptor coupling to Gq. We previously demonstrated that S1P confers cardioprotection against ischemia/reperfusion by activating RhoA and its downstream effector PKD. The S1P receptor subtypes and G proteins that regulate RhoA activation and downstream responses in the heart have not been determined. Using siRNA or pertussis toxin to inhibit different G proteins in NRVMs we established that S1P regulates RhoA activation through Gα13but not Gα12, Gαq, or Gαi. Knockdown of the three major S1P receptors using siRNA demonstrated a requirement for S1P3in RhoA activation and subsequent phosphorylation of PKD, and this was confirmed in studies using isolated hearts from S1P3knockout (KO) mice. S1P treatment reduced infarct size induced by ischemia/reperfusion in Langendorff perfused wild-type (WT) hearts and this protection was abolished in the S1P3KO mouse heart. CYM-51736, an S1P3-specific agonist, also decreased infarct size after ischemia/reperfusion to a degree similar to that achieved by S1P. The finding that S1P3receptor- and Gα13-mediated RhoA activation is responsible for protection against ischemia/reperfusion suggests that selective targeting of S1P3receptors could provide therapeutic benefits in ischemic heart disease.
authors.affiliation: Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
authors.forename: Bryan S
authors.initials: BS
authors.lastname: Yung
authors.affiliation: Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
authors.forename: Cameron S
authors.initials: CS
authors.lastname: Brand
authors.affiliation: Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
authors.forename: Sunny Y
authors.initials: SY
authors.lastname: Xiang
authors.affiliation: Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
authors.forename: Charles B B
authors.initials: CB
authors.lastname: Gray
authors.affiliation: Grifols Inc., Los Angeles, CA 90032, United States.
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Means
authors.affiliation: Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037, United States.
authors.forename: Hugh
authors.initials: H
authors.lastname: Rosen
authors.affiliation: Department of Molecular and Cellular Neuroscience, Dorris Neuroscience Center, Scripps Research Institute, La Jolla, CA 92037, United States.
authors.forename: Jerold
authors.initials: J
authors.lastname: Chun
authors.affiliation: Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
authors.forename: Nicole H
authors.initials: NH
authors.lastname: Purcell
authors.affiliation: Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States. Electronic address: jhbrown@ucsd.edu.
authors.forename: Joan Heller
authors.initials: JH
authors.lastname: Brown
authors.affiliation: Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States. Electronic address: smiyamoto@ucsd.edu.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Miyamoto
mesh_terms: D000818:Animals; D006332:Cardiomegaly / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D008246:Lysophospholipids / Q000378:metabolism; D008297:Male; D051379:Mice; D015428:Myocardial Reperfusion Injury / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000378:metabolism*; D043484:Proprotein Convertases / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D049349:Receptors, Lysosphingolipid / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000378:metabolism*; D015398:Signal Transduction; D013110:Sphingosine / Q000031:analogs & derivatives / Q000378:metabolism; D050396:TRPP Cation Channels / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: D008246:Lysophospholipids; D049349:Receptors, Lysosphingolipid; D050396:TRPP Cation Channels; C060506:sphingosine 1-phosphate; D043484:Proprotein Convertases; D012697:Serine Endopeptidases; C115575:membrane-bound transcription factor peptidase, site 1; D020742:rhoA GTP-Binding Protein; D013110:Sphingosine
keywords: Cardioprotection; G protein-coupled receptor (GPCR); Ischemia/reperfusion (I/R); Phospholipase C (PLC); Protein kinase D (PKD); Ras homolog gene family member A (RhoA); Sphingosine-1-phosphate (S1P)