Tyro-3 receptor tyrosine kinase and its ligand, Gas6, stimulate the function of osteoclasts

Tyro-3受体酪氨酸激酶及其配体Gas6刺激破骨细胞功能

基本信息

批准号：
10671711
负责人：
HANEDA Yoshiyuki
金额：
$ 2.05万
依托单位：
Meikai University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10671711/
关键词：
Osteoclasts Bone resorption Bone marrow cells Gas6 Tyro3 c-src FAK PI3-kinase Tyro-3 トランスフェクション Quantitative RT-PCR Tyrosine phosphorylation

项目摘要

Bone is continuously being formed and resorbed. This process is accomplished by the precise coordination of two cell types: osteoblasts and osteoclasts. Osteoclasts are large, multinucleated cells that are derived from the same hematopoietic precursors as macrophages. However, these bone-resorbing cells are difficult to study directly because of their relative inaccessibility. The purification of primary osteoclasts from rabbit bones by their adherent nature provides an opportunity for investigating the molecules in osteoclasts. We have examined the expression of receptor tyrosine kinases by PCR and found that Tyro-3 was frequently cloned from primary osteoclasts in PCR cloning. Immunohistochemistry revealed that Tyro-3 was expressed on the multinucleated osteoclasts which were positive for tartrate-resistant acid phosphatase (TRAP), but not on mononuclear TRAP-positive cells. The Tyro-3 ligand, Gas6 induced the phosphorylation of Tyro-3 receptors in osteoclasts in 5-10 mm Gas6 and protein S directly enhanced the bone-resorbing activity of mature osteoclasts. However, Gas6 did not affect the differentiation of osteoclasts from bone marrow cells. Gas6 and protein S are dependent on vitamin K, a cofactor for the enzyme responsible for carboxylation of glutamic acid residues. The findings in this study are the first to indicate a new biological activity of Gas6 and protein S as a direct regulator of osteoclastic function and give an insight into the role of these vitamin K-dependent ligands are involved in bone resorption in vivo.

骨骼不断形成和吸收。这个过程是通过两种细胞类型的精确协调来完成的：成骨细胞和破骨细胞。破骨细胞是大型多核细胞，源自与巨噬细胞相同的造血前体细胞。然而，由于这些骨吸收细胞相对难以接近，因此很难直接研究。通过其粘附性质从兔骨中纯化初级破骨细胞为研究破骨细胞中的分子提供了机会。我们通过PCR检测了受体酪氨酸激酶的表达，发现Tyro-3在PCR克隆中经常从原代破骨细胞中克隆出来。免疫组织化学显示Tyro-3在抗酒石酸酸性磷酸酶(TRAP)阳性的多核破骨细胞上表达，但在单核TRAP阳性细胞上不表达。 Tyro-3配体Gas6诱导5-10mm破骨细胞中Tyro-3受体磷酸化，Gas6和蛋白S直接增强成熟破骨细胞的骨吸收活性。然而，Gas6并不影响破骨细胞从骨髓细胞的分化。 Gas6 和蛋白质 S 依赖于维生素 K，维生素 K 是负责谷氨酸残基羧化的酶的辅助因子。这项研究的结果首次表明 Gas6 和蛋白 S 作为破骨细胞功能的直接调节剂具有新的生物活性，并深入了解这些维生素 K 依赖性配体在体内骨吸收中的作用。