Rho-kinase inhibitors decrease TGF-beta-stimulated VEGF synthesis through stress-activated protein kinase/c-Jun N-terminal kinase in osteoblasts.
We have previously reported that transforming growth factor-beta (TGF-beta) stimulates the synthesis of vascular endothelial growth factor (VEGF) through p44/p42 mitogen-activated protein (MAP) kinase, p38 MAP kinase and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) in osteoblast-like MC3T3-E1 cells. In order to investigate whether Rho-kinase is involved in the TGF-beta-stimulated VEGF synthesis in these cells we examined the effects of Rho-kinase inhibitors on the VEGF synthesis. TGF-beta time-dependently induced the phosphorylation of myosin phosphatase targeting subunit (MYPT-1) which is a well known substrate of Rho-kinase. Y27632 and fasudil, Rho-kinase inhibitors, significantly reduced the TGF-beta-stimulated VEGF synthesis as well as the MYPT-1 phosphorylation. Y27632 and fasudil failed to affect the TGF-beta-induced phosphorylation of p44/p42 MAP kinase, p38 MAP kinase or Smad2. On the contrary, Y27632 as well as fasudil markedly suppressed the TGF-beta-induced phosphorylation of SAPK/JNK. Taken together, our results strongly suggest that Rho-kinase regulates TGF-beta-stimulated VEGF synthesis via SAPK/JNK activation in osteoblasts.
Kuno
Masashi
M
Department of Pharmacology, Gifu University Graduate School of Medicine, Gifu, Japan.
Takai
Shinji
S
Matsushima-Nishiwaki
Rie
R
Minamitani
Chiho
C
Mizutani
Jun
J
Otsuka
Takanobu
T
Harada
Atsushi
A
Adachi
Seiji
S
Kozawa
Osamu
O
Tokuda
Haruhiko
H
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives / Q000494:pharmacology; D016475:3T3 Cells; D000818:Animals; D000831:Animals, Newborn; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D051379:Mice; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism; D043263:Myosin-Light-Chain Phosphatase; D010006:Osteoblasts / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012886:Skull / Q000166:cytology / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors*
D004791:Enzyme Inhibitors; D047428:Protein Kinase Inhibitors; D016212:Transforming Growth Factor beta; D042461:Vascular Endothelial Growth Factor A; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D054460:rho-Associated Kinases; D009219:Myosin-Light-Chain Kinase; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D043263:Myosin-Light-Chain Phosphatase; C510645:Ppp1r12a protein, mouse; C049347:fasudil