Endothelins inhibit the mineralization of osteoblastic MC3T3-E1 cells through the A-type endothelin receptor.
We examined the effects of various endothelins on the mineralization of mouse clonal preosteoblastic MC3T3-E1 cells. MC3T3-E1 cells expressed mRNAs for endothelin (ET)-1 and the A-type receptor for ET (ETA). A pharmacological study also demonstrated the predominant expression of the ETA receptor. Northern blotting analysis revealed that ETs decreased the expression of mRNA for osteocalcin, which is a marker protein for the maturation of osteoblastic cells. ET-1 also decreased in the deposition of calcium by MC3T3-E1 cells in a dose-dependent manner and it had an inhibitory effect even at 10(-11) M. The rank order of potency of ETs was ET-1 = ET-2 > ET-3. Brief treatment with 10(-7) M ET-1 on days 6-8 alone suppressed mineralization. ET-1 enhanced the rate of production of inositol 1,4, 5-trisphosphate (IP3) in MC3T3-E1 cells, but it had no effect on the rate of production of cAMP. Taken together, our data indicate that ET-1 might inhibit the mineralization of osteoblastic cells via an interaction with the ETA receptor, with generation of IP3 as the intracellular signal.
Hiruma
Y
Y
Research Center for Experimental Biology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
Inoue
A
A
Shiohama
A
A
Otsuka
E
E
Hirose
S
S
Yamaguchi
A
A
Hagiwara
H
H
D000818:Animals; D002113:Calcification, Physiologic / Q000187:drug effects / Q000502:physiology*; D002118:Calcium; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D017931:DNA Primers; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000378:metabolism / Q000494:pharmacology; D019333:Endothelin-2 / Q000494:pharmacology; D019334:Endothelin-3 / Q000494:pharmacology; D016232:Endothelins / Q000494:pharmacology* / Q000502:physiology; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D051379:Mice; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D015675:Osteocalcin / Q000096:biosynthesis / Q000235:genetics; D010456:Peptides, Cyclic / Q000494:pharmacology; D044022:Receptor, Endothelin A; D017466:Receptors, Endothelin / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
D017931:DNA Primers; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D019333:Endothelin-2; D019334:Endothelin-3; D016232:Endothelins; D010456:Peptides, Cyclic; D044022:Receptor, Endothelin A; D017466:Receptors, Endothelin; D015675:Osteocalcin; D015544:Inositol 1,4,5-Trisphosphate; D000242:Cyclic AMP; C072247:cyclo(Trp-Asp-Pro-Val-Leu); D002118:Calcium