Study of roles of receptor tyrosine kinases in regulating osteoclast function.

受体酪氨酸激酶在调节破骨细胞功能中的作用研究。

基本信息

批准号：
09470393
负责人：
KUMEGAWA Masayoshi
金额：
$ 5.12万
依托单位：
Meikai University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

This project was undertaken to elucidate the mechanism for regulation of osteoclast function at molecular level. To address the aim, we first needed a pure population of functional osteoclasts, and succeeded in developing a new method for isolation of mature osteoclasts. Using the isolated osteoclasts, we focused on elucidating the roles of receptor tyrosine kinases in the regulation of osteoclastic function. In this study, we cloned eight receptor tyrosine kinases, including fibroblast growth factor receptor-1(FGFR-1),Tyro3, vascular epithelial growth factor receptors(Fit-1 and Flk-1), insulin receptor, c-fms, and c-met, expressed on mature osteoclasts. Besides these receptor tyrosine kinases, we also detected some receptor serine/threonine kinases such as a subtype of prostaglandin (PG) E2 receptor, EP4 and Bone morphogenetic receptors (BMPR-IA and BMPR-II) in osteoclasts. We found the signaling through FGFR-1,Tyro3, and VEGF receptors stimulated the osteoclastic bone resorption and/or the osteoclast survival. These receptors associated with c-src, FAK, P13K, and 42/44p MAPKs to express the stimulatory effects. On the other hand, PGE2 inhibited the osteoclastic bone-resorbing activity through the EP4 receptor coupled with Gs-protein, whereas BMP-2 stimulated the activity through its receptors/Smads. Thus, mature osteoclasts express many receptor tyrosine kinases as well as serine/threonine kinase receptors on their plasma membranes to regulate their functions, and these results provide us a lot of insights to understand the regulatory mechanism for osteoclast.

该项目的目的是阐明在分子水平上调节破骨细胞功能的机制。为了实现这一目标，我们首先需要纯的功能性破骨细胞群，并成功开发了一种分离成熟破骨细胞的新方法。使用分离的破骨细胞，我们重点阐明受体酪氨酸激酶在破骨细胞功能调节中的作用。在本研究中，我们克隆了8个受体酪氨酸激酶，包括成纤维细胞生长因子受体-1（FGFR-1）、Tyro3、血管上皮生长因子受体（Fit-1和Flk-1）、胰岛素受体、c-fms和c -met，在成熟破骨细胞上表达。除了这些受体酪氨酸激酶外，我们还在破骨细胞中检测到了一些受体丝氨酸/苏氨酸激酶，例如前列腺素（PG）E2受体的亚型、EP4和骨形态发生受体（BMPR-IA和BMPR-II）。我们发现通过 FGFR-1、Tyro3 和 VEGF 受体的信号传导刺激破骨细胞骨吸收和/或破骨细胞存活。这些受体与 c-src、FAK、P13K 和 42/44p MAPK 相关，以表达刺激作用。另一方面，PGE2通过与Gs蛋白偶联的EP4受体抑制破骨细胞的骨吸收活性，而BMP-2通过其受体/Smads刺激该活性。因此，成熟的破骨细胞在其质膜上表达许多受体酪氨酸激酶以及丝氨酸/苏氨酸激酶受体来调节其功能，这些结果为我们了解破骨细胞的调节机制提供了很多见解。