Li Xinyue, Wang Zhitao, Yang Li, Li Zhengyang, Ogata Yorimasa
Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
J Oral Sci. 2010 Jun;52(2):221-9. doi: 10.2334/josnusd.52.221.
Endothelin-1 (ET-1) was originally discovered as a vasoconstrictor protein excreted by vascular endothelial cells. Recently, tumor-produced ET-1 has been considered to stimulate osteoblasts to form new bone, and to be an important mediator of osteoblastic bone metastasis. ET-1 has high affinity for two different membrane receptors, ET(A)R and ET(B)R, which are expressed by many types of cells including osteoblasts. Bone sialoprotein (BSP) is a phosphorylated and sulfated glycoprotein associated with mineralized connective tissues. To investigate the effects of ET-1 on BSP transcription, we used rat osteoblast-like ROS17/2.8 cells. Levels of BSP and osteopontin mRNA were increased at 12 h after treatment with ET-1 (10 ng/ml), and ET-1 at the same concentration induced luciferase activity of a -116 to +60 BSP promoter construct at 6 h. Transcriptional activity of -84BSPLUC, which contains the cAMP response element (CRE), was increased by ET-1. Furthermore, at 6 h, ET-1 (10 ng/ml) increased the binding of nuclear protein to CRE, the FGF2 response element (FRE) and the homeodomain protein-binding site (HOX). Antibodies against CREB1, JunD and Fra2 disrupted the formation of CRE-protein complexes, while antibodies against Runx2 and Dlx5 reduced the formation of FRE- and HOX-protein complexes. These findings indicate that ET-1 increases BSP transcription via the CRE, FRE and HOX sites in the rat BSP gene promoter.
内皮素 -1（ET -1）最初被发现是一种由血管内皮细胞分泌的血管收缩蛋白。最近，肿瘤产生的ET -1被认为可刺激成骨细胞形成新骨，并且是成骨性骨转移的重要介质。ET -1对两种不同的膜受体ET(A)R和ET(B)R具有高亲和力，这两种受体在包括成骨细胞在内的多种细胞类型中表达。骨唾液蛋白（BSP）是一种与矿化结缔组织相关的磷酸化和硫酸化糖蛋白。为了研究ET -1对BSP转录的影响，我们使用了大鼠成骨样ROS17/2.8细胞。用ET -1（10 ng/ml）处理12小时后，BSP和骨桥蛋白mRNA水平升高，相同浓度的ET -1在6小时时诱导了 -116至 +60 BSP启动子构建体的荧光素酶活性。含有cAMP反应元件（CRE）的 -84BSPLUC的转录活性被ET -1增强。此外，在6小时时，ET -1（10 ng/ml）增加了核蛋白与CRE、FGF2反应元件（FRE）和同源结构域蛋白结合位点（HOX）的结合。针对CREB1、JunD和Fra2的抗体破坏了CRE -蛋白复合物的形成，而针对Runx2和Dlx5的抗体减少了FRE -和HOX -蛋白复合物的形成。这些发现表明ET -1通过大鼠BSP基因启动子中的CRE、FRE和HOX位点增加BSP转录。
