Stimulatory effect of endothelin-1 on Na-dependent phosphate transport and its signaling mechanism in osteoblast-like cells.
Endothelin-1 (ET-1) has been reported to modulate bone metabolism both in vivo and in vitro. In the present study, we investigated the effect of ET-1 on inorganic phosphate (Pi) transport in osteoblast-like cells, which is now considered to be important for the initiation of bone matrix calcification. ET-1 time- and dose-dependently stimulated Na-dependent Pi transport in mouse calvaria-derived osteoblast-like MC3T3-E1 cells, and this effect was dependent on transcriptional and translational process. Kinetic analysis indicated that the change in Pi transport activity induced by ET-1 was due to alteration in the number of the Pi transporter. BQ123, a selective antagonist for ET(A) receptor, suppressed the ET-1-induced Pi transport, but BQ788, a selective antagonist for ET(B) receptor, had no effect. The inhibition of phosphoinositide hydrolysis by phospholipase C (PLC) partially attenuated the Pi transport by ET-1. Propranolol, which inhibits phosphatidic acid phosphohydrolase, also suppressed ET-1-induced Pi transport. On the contrary, indomethacin did not affect the stimulatory effect of Pi transport by ET-1. Calphostin C, a protein kinase C (PKC) inhibitor, significantly blunted the stimulatory effect of ET-1 on Pi transport. Combined effect of PMA and ET-1 on Pi transport was not additive. Pi transport induced by ET-1 was also suppressed in PKC down-regulated cells. In conclusion, the results of the present study indicate that in MC3T3-E1 osteoblast-like cells, ET-1 acting through ET receptor links to a stimulation of Pi transport via activation of PKC through both phosphoinositide and phosphatidylcholine hydrolyses.
Masukawa
H
H
First Department of Internal Medicine, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
Miura
Y
Y
Sato
I
I
Oiso
Y
Y
Suzuki
A
A
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D051379:Mice; D009281:Naphthalenes / Q000494:pharmacology; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism*; D011433:Propranolol / Q000494:pharmacology; D014176:Protein Biosynthesis / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D012886:Skull; D012964:Sodium / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects
D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D009281:Naphthalenes; D010710:Phosphates; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin; D003609:Dactinomycin; D003513:Cycloheximide; D012964:Sodium; D011433:Propranolol; D011493:Protein Kinase C; C058819:calphostin C; D007213:Indomethacin