Function of Rho-kinase in prostaglandin D2-induced interleukin-6 synthesis in osteoblasts.
We have previously reported that prostaglandin D2 (PGD2) stimulates interleukin-6 (IL-6), a potent bone resorptive agent, in osteoblast-like MC3T3-E1 cells. In the present study, we investigated whether Rho-kinase is implicated in the PGD2-stimulated IL-6 synthesis in MC3T3-E1 cells. PGD2 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 PGD2-stimulated IL-6 synthesis as well as the MYPT-1 phosphorylation. Fasudil, another inhibitor of Rho-kinase, suppressed the PGD2-stimulated IL-6 synthesis. The PGD2-stimulated IL-6 synthesis was reduced by PD98059, a MEK inhibitor, and SB203580, an inhibitor of p38 mitogen-activated protein (MAP) kinase, but not SP600125, an inhibitor of stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK). However, Y27632 and fasudil failed to affect the PGD2-induced phosphorylation of p44/p42 MAP kinase. On the other hand, Y27632 as well as fasudil markedly attenuated the PGD2-induced phosphorylation of p38 MAP kinase. In addition, PGD2 additively induced IL-6 synthesis in combination with endothelin-1 which induces IL-6 synthesis through p38 MAP kinase regulated by Rho-kinase. These results strongly suggest that Rho-kinase regulates PGD2-stimulated IL-6 synthesis via p38 MAP kinase activation in osteoblasts.
Tokuda
Haruhiko
H
Department of Clinical Laboratory, National Hospital for Geriatric Medicine, National Center for Geriatrics and Gerontology, 36-3 Gengo, Obu, Aichi 474-8511, Japan. tokuda@ncgg.go.jp
Takai
Shinji
S
Matsushima-Nishiwaki
Rie
R
Hanai
Yoshiteru
Y
Adachi
Seiji
S
Minamitani
Chiho
C
Mizutani
Jun
J
Otsuka
Takanobu
T
Kozawa
Osamu
O
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives / Q000494:pharmacology; D000577:Amides / Q000494:pharmacology; D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis*; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000187:drug effects / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000187:drug effects / Q000378:metabolism; D009219:Myosin-Light-Chain Kinase / Q000187:drug effects / Q000378:metabolism; D043263:Myosin-Light-Chain Phosphatase; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D015230:Prostaglandin D2 / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology; D013329:Structure-Activity Relationship; D048051:p38 Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism; D054460:rho-Associated Kinases / Q000502:physiology*
D000577:Amides; D000873:Anthracenes; D019332:Endothelin-1; D005419:Flavonoids; D007093:Imidazoles; D015850:Interleukin-6; D011725:Pyridines; C108830:Y 27632; C432165:pyrazolanthrone; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D054460:rho-Associated Kinases; D009219:Myosin-Light-Chain Kinase; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; D043263:Myosin-Light-Chain Phosphatase; C510645:Ppp1r12a protein, mouse; C093642:SB 203580; C049347:fasudil; D015230:Prostaglandin D2; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one