Signaling mechanisms of sphingosine 1-phosphate-induced ERK1/2 activation in cultured feline esophageal smooth muscle cells.
Sphingosine 1-phosphate (S1P) is a bioactive lipid, stored and released from activated platelets, macrophages, and other mammalian cells. We previously reported that S1P induces esophageal smooth muscle contraction in freshly isolated intact cells. Here, we measured S1P-induced ERK1/2 activation and upstream signaling in cultured feline esophageal smooth muscle cells. Activation of ERK1/2 by S1P peaked at 5 min, was sustained up to 30 min, and was blocked by PTX. In contrast, S1P did not activate p38 MAPK or JNK. PTX inhibited S1P-induced ERK1/2 activation. We then used phospholipase inhibitors, DEDA for PLA(2), U73122 for PLC, and rhoCMB for PLD, to determine that ERK1/2 activation was downstream of PLC activation. The PKC inhibitors, GF109203X and chelerythrine, also suppressed ERK1/2 activation. Whereas the PTK inhibitor, genistein, partially inhibited ERK1/2 activation, the EGFR tyrosine kinase inhibitor, tyrphostin 51, had no effect. Taken together, S1P-induced ERK1/2 activation in cultured ESMCs requires a PTX-sensitive G protein, stimulation of the PLC pathway, and subsequent activation of the PKC and PTK pathways.
Chung
Fa Yong
FY
Department of Pharmacology, College of Pharmacy, Chung Ang University, Seoul 156-756, Korea.
Song
Hyun Ju
HJ
Park
Sun Young
SY
Jang
Hyeon Soo
HS
Kim
Dong-Seok
DS
Sim
Sang Soo
SS
Sohn
Uy Dong
UD
D000818:Animals; D015153:Blotting, Western; D002415:Cats; D002469:Cell Separation; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004947:Esophagus / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D066298:In Vitro Techniques; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008246:Lysophospholipids / Q000494:pharmacology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D037342:Pertussis Toxin / Q000494:pharmacology; D010740:Phospholipases / Q000037:antagonists & inhibitors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D015398:Signal Transduction / Q000187:drug effects*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D004791:Enzyme Inhibitors; D008246:Lysophospholipids; C060506:sphingosine 1-phosphate; D037342:Pertussis Toxin; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; D010740:Phospholipases; D013110:Sphingosine