Cardiomyocyte S1P1 receptor-mediated extracellular signal-related kinase signaling and desensitization.
We examined the ability of sphingosine-1-phosphate (S1P) to desensitize extracellular signal-related kinase (ERK), a mitogen-activated protein kinase linked to antiapoptotic responses in the heart. In isolated adult mouse cardiomyocytes, S1P (10 nM-5 microM) induced ERK phosphorylation in a time- and dose-dependent manner. S1P stimulation of ERK was completely inhibited by an S1P1/3 subtype receptor antagonist (VPC23019), by a Gi protein inhibitor (pertussis toxin) and by a mitogen-activated protein kinase/ERK kinase inhibitor (PD98059). A selective S1P3 receptor antagonist (CAY10444) had no effect on S1P-induced ERK activation. The selective S1P1 agonist SEW2871 also induced ERK phosphorylation. Activation of ERK by restimulation with 100 nM S1P was suppressed after 1 hour of preincubation with 100 nM S1P but recovered fully the next day, suggesting receptor recycling. Similar results were obtained in protein kinase C epsilon-null cardiomyocytes. Treatment with the nonselective S1P receptor agonist FTY720 for 1 hour also reduced phospho-ERK expression in response to subsequent S1P stimulation. In contrast to S1P, some desensitization to FTY720 persisted after overnight exposure. Cell death induced by hypoxia/reoxygenation was reduced by pretreatment with exogenous S1P. This enhanced survival was abrogated by pretreatment with PD98059, VPC23019, or pertussis toxin. Thus, exogenous S1P induces rapid and reversible S1P1-mediated ERK phosphorylation. S1P-induced adult mouse cardiomyocyte survival requires ERK activation mediated via an S1P1-Gi pathway.
Tao
Rong
R
Department of Medicine, Veterans Affairs Medical Center, University of California, San Francisco, CA 94121, USA.
Hoover
Holly E
HE
Zhang
Jianqing
J
Honbo
Norman
N
Alano
Conrad C
CC
Karliner
Joel S
JS
D000818:Animals; D016923:Cell Death / Q000187:drug effects; D015687:Cell Hypoxia; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D066298:In Vitro Techniques; D008246:Lysophospholipids / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000235:genetics; D049349:Receptors, Lysosphingolipid / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*; D015398:Signal Transduction; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D053778:Thiazolidines / Q000494:pharmacology
C000609617:CAY10444; D008246:Lysophospholipids; D049349:Receptors, Lysosphingolipid; D053778:Thiazolidines; C060506:sphingosine 1-phosphate; D011493:Protein Kinase C; D048049:Extracellular Signal-Regulated MAP Kinases; D013110:Sphingosine