Involvement of Rho-kinase in prostaglandin F2alpha-stimulated interleukin-6 synthesis via p38 mitogen-activated protein kinase in osteoblasts.
We have previously reported that prostaglandin F(2alpha) (PGF(2alpha)) stimulates interleukin-6 (IL-6), a potent bone resorptive agent, through p44/p42 mitogen-activated protein (MAP) kinase in osteoblast-like MC3T3-E1 cells. In the present study, we investigated whether Rho-kinase is implicated in the PGF(2alpha)-stimulated IL-6 synthesis in MC3T3-E1 cells. PGF(2alpha) time-dependently induced the phosphorylation of myosin phosphatase targeting subunit (MYPT-1), a Rho-kinase substrate. Y27632, a specific Rho-kinase inhibitor, significantly reduced the PGF(2alpha)-stimulated IL-6 synthesis as well as the MYPT-1 phosphorylation. Fasudil, another inhibitor of Rho-kinase, suppressed the PGF(2alpha)-stimulated IL-6 synthesis. Y27632 and fasudil failed to affect the PGF(2alpha)-induced phosphorylation of p44/p42 MAP kinase. SB203580 and BIRB0796, potent inhibitors of p38 MAP kinase, suppressed the IL-6 synthesis induced by PGF(2alpha). While SP600125, an inhibitor of stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK), failed to reduce the synthesis. Y27632 as well as fasudil attenuated the PGF(2alpha)-induced phosphorylation of p38 MAP kinase. These results strongly suggest that Rho-kinase regulates PGF(2alpha)-stimulated IL-6 synthesis via p38 MAP kinase activation in osteoblasts.
Minamitani
Chiho
C
Department of Orthopedic Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan.
Otsuka
Takanobu
T
Takai
Shinji
S
Matsushima-Nishiwaki
Rie
R
Adachi
Seiji
S
Hanai
Yoshiteru
Y
Mizutani
Jun
J
Tokuda
Haruhiko
H
Kozawa
Osamu
O
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives / Q000378:metabolism; D016475:3T3 Cells; D000818:Animals; D015237:Dinoprost / Q000235:genetics / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000378:metabolism; D015850:Interleukin-6 / Q000096:biosynthesis*; D051379:Mice; D009219:Myosin-Light-Chain Kinase / Q000235:genetics / Q000378:metabolism; D043263:Myosin-Light-Chain Phosphatase; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
D004791:Enzyme Inhibitors; D015850:Interleukin-6; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D015237:Dinoprost; D054460:rho-Associated Kinases; D009219:Myosin-Light-Chain Kinase; D048051:p38 Mitogen-Activated Protein Kinases; D043263:Myosin-Light-Chain Phosphatase; C510645:Ppp1r12a protein, mouse; C049347:fasudil