Sphingosine 1-phosphate induces cyclooxygenase-2 via Ca2+-dependent, but MAPK-independent mechanism in rat vascular smooth muscle cells.
The effects of sphingosine 1-phosphate (S1P) on prostaglandin I(2) (PGI(2)) production and cyclooxygenase (COX) expression in cultured rat vascular smooth muscle cells (VSMCs) were investigated. S1P stimulated PGI(2) production in a concentration-dependent manner, which was completely suppressed by NS-398, a selective COX-2 inhibitor, as determined by radioimmunoassay. S1P stimulated COX-2 protein and mRNA expressions in a concentration- and time-dependent manner, while it had no effect on COX-1 expression. S1P(2) and S1P(3) receptors mRNA were abundantly expressed in rat VSMCs. Suramin, an antagonist of S1P(3) receptor, almost completely inhibited S1P-induced COX-2 expression. Pretreatment of VSMCs with pertussis toxin (PTX) partially, but significantly inhibited S1P-induced PGI(2) production and COX-2 expression. S1P also activated extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK). However, neither PD 98059, a selective inhibitor of ERK activation, nor SB 203580, a selective inhibitor of p38 MAPK, had a significant inhibitory effect on S1P-induced COX-2 expression, suggesting that the MAPK activation does not play main roles in S1P-induced COX-2 induction. S1P-induced COX-2 expression was inhibited by PP2, an inhibitor of Src-family tyrosine kinase, Ca(2+) depletion, and GF 109203X, an inhibitor of protein kinase C (PKC). These results suggest that S1P stimulates COX-2 induction in rat VSMCs through mechanisms involving Ca(2+)-dependent PKC and Src-family tyrosine kinase activation via S1P(3) receptor coupled to PTX-sensitive and -insensitive G proteins.
Nodai
Akiko
A
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan.
Machida
Takuji
T
Izumi
Sachiko
S
Hamaya
Yumika
Y
Kohno
Takayuki
T
Igarashi
Yasuyuki
Y
Iizuka
Kenji
K
Minami
Masaru
M
Hirafuji
Masahiko
M
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D051546:Cyclooxygenase 2 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D011464:Epoprostenol / Q000096:biosynthesis* / Q000378:metabolism; D008246:Lysophospholipids / Q000494:pharmacology*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000201:enzymology*; D009578:Nitrobenzenes / Q000494:pharmacology; D037342:Pertussis Toxin / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D049349:Receptors, Lysosphingolipid / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
D016861:Cyclooxygenase Inhibitors; D008246:Lysophospholipids; D009578:Nitrobenzenes; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D049349:Receptors, Lysosphingolipid; D013449:Sulfonamides; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; C060506:sphingosine 1-phosphate; D011464:Epoprostenol; D051546:Cyclooxygenase 2; D037342:Pertussis Toxin; D019061:src-Family Kinases; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D013110:Sphingosine; D002118:Calcium