Hiruma Y, Inoue A, Shiohama A, Otsuka E, Hirose S, Yamaguchi A, Hagiwara H
Research Center for Experimental Biology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
Am J Physiol. 1998 Oct;275(4):R1099-105. doi: 10.1152/ajpregu.1998.275.4.R1099.
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.
我们研究了各种内皮素对小鼠克隆前成骨细胞MC3T3-E1细胞矿化的影响。MC3T3-E1细胞表达内皮素（ET）-1和ET A型受体（ETA）的mRNA。药理学研究还证实了ETA受体的主要表达。Northern印迹分析显示，内皮素降低了骨钙素mRNA的表达，骨钙素是成骨细胞成熟的标志物蛋白。ET-1还以剂量依赖的方式降低了MC3T3-E1细胞的钙沉积，即使在10^(-11) M时也具有抑制作用。内皮素的效力顺序为ET-1 = ET-2 > ET-3。仅在第6至8天用10^(-7) M ET-1进行短暂处理就抑制了矿化。ET-1提高了MC3T3-E1细胞中肌醇1,4,5-三磷酸（IP3）的产生速率，但对cAMP的产生速率没有影响。综上所述，我们的数据表明，ET-1可能通过与ETA受体相互作用，以IP3作为细胞内信号来抑制成骨细胞的矿化。
