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.
Research Center for Experimental Biology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
Y
Y
Hiruma
A
A
Inoue
A
A
Shiohama
E
E
Otsuka
S
S
Hirose
A
A
Yamaguchi
H
H
Hagiwara
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