Inhibition by adenylyl cyclase-cAMP system of ET-1-induced HSP27 in osteoblasts.
We have previously reported that endothelin-1 (ET-1) stimulates heat shock protein (HSP) 27 induction in osteoblast-like MC3T3-E1 cells and that p38 mitogen-activated protein (MAP) kinase acts at a point downstream from protein kinase C (PKC) in HSP27 induction. In the present study, we investigated the effect of the adenylyl cyclase-cAMP system on ET-1-stimulated induction of HSP27 in MC3T3-E1 cells. Dibutyryl-cAMP (DBcAMP) dose dependently inhibited the HSP27 accumulation stimulated by ET-1. Forskolin and cholera toxin significantly suppressed the ET-1-stimulated accumulation of HSP27. However, dideoxyforskolin, a forskolin derivative that does not activate cAMP, failed to suppress the ET-1-induced HSP27 accumulation. Forskolin reduced the p38 MAP kinase phosphorylation induced by ET-1 or 12-O-tetradecanoylphorbol-13-acetate (TPA). PGE(1), an extracellular agonist that activates cAMP production, reduced the ET-1-induced HSP27 accumulation. In addition, the phosphorylation of p38 MAP kinase induced by ET-1 or TPA was suppressed by PGE(1). Forskolin, DBcAMP, and PGE(1) suppressed the ET-1-stimulated increase in the mRNA level for HSP27. These results indicate that the adenylyl cyclase-cAMP system has an inhibitory role in ET-1-stimulated HSP27 induction in osteoblasts and that the effect is exerted at the point between PKC and p38 MAP kinase in osteoblasts.
Hatakeyama
D
D
Department of Pharmacology, Gifu University School of Medicine, Gifu 500 - 8705, Japan.
Kozawa
O
O
Niwa
M
M
Matsuno
H
H
Kato
K
K
Tatematsu
N
N
Shibata
T
T
Uematsu
T
T
D000067956:Adenylyl Cyclase Inhibitors; D000527:Alprostadil / Q000494:pharmacology; D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D003994:Bucladesine / Q000494:pharmacology; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D019332:Endothelin-1 / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006360:Heat-Shock Proteins; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis / Q000302:isolation & purification; D048051:p38 Mitogen-Activated Protein Kinases
D000067956:Adenylyl Cyclase Inhibitors; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D006360:Heat-Shock Proteins; C486113:Hsbp1 protein, mouse; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D005576:Colforsin; D003994:Bucladesine; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D000527:Alprostadil