Abstract
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.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / analogs & derivatives
-
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / pharmacology
-
Amides / pharmacology
-
Animals
-
Anthracenes / pharmacology
-
Cells, Cultured
-
Dose-Response Relationship, Drug
-
Endothelin-1 / pharmacology
-
Flavonoids / pharmacology
-
Imidazoles / pharmacology
-
Interleukin-6 / biosynthesis*
-
Mice
-
Mitogen-Activated Protein Kinase 1 / drug effects
-
Mitogen-Activated Protein Kinase 1 / metabolism
-
Mitogen-Activated Protein Kinase 3 / drug effects
-
Mitogen-Activated Protein Kinase 3 / metabolism
-
Myosin-Light-Chain Kinase / drug effects
-
Myosin-Light-Chain Kinase / metabolism
-
Myosin-Light-Chain Phosphatase
-
Osteoblasts / drug effects*
-
Osteoblasts / metabolism*
-
Phosphorylation / drug effects
-
Prostaglandin D2 / pharmacology*
-
Pyridines / pharmacology
-
Structure-Activity Relationship
-
p38 Mitogen-Activated Protein Kinases / drug effects
-
p38 Mitogen-Activated Protein Kinases / metabolism
-
rho-Associated Kinases / physiology*
Substances
-
Amides
-
Anthracenes
-
Endothelin-1
-
Flavonoids
-
Imidazoles
-
Interleukin-6
-
Pyridines
-
Y 27632
-
pyrazolanthrone
-
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
-
rho-Associated Kinases
-
Myosin-Light-Chain Kinase
-
Mitogen-Activated Protein Kinase 1
-
Mitogen-Activated Protein Kinase 3
-
p38 Mitogen-Activated Protein Kinases
-
Myosin-Light-Chain Phosphatase
-
Ppp1r12a protein, mouse
-
SB 203580
-
fasudil
-
Prostaglandin D2
-
2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one