Molecular mechanism of bone-resorption in osteoclasts through microtubule regulation

微管调节破骨细胞骨吸收的分子机制

• 批准号: 23659707
• 负责人: TANAKA Sakae
• 金额: $ 2.33万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Challenging Exploratory Research
• 财政年份: 2011
• 资助国家: 日本
• 起止时间: 2011 至 2012
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-23659707/
• 关键词: 骨; 軟骨代謝学; 破骨細胞; 微小管; AKT; Akt

We investigated the role of Akt, a downstream effector of phosphatidylinositol 3-kinase, in bone-resorbing activity of mature osteoclasts. Treatment with a specific Akt inhibitor disrupted sealing zone formation and decreased the bone-resorbing activity of osteoclasts. The normal microtubule structures were lost and the Akt inhibitor reduced the amount of acetylated tubulin, which reflects stabilized microtubules, whereas forced Akt activation by adenovirus vectors resulted in the opposite effect. Forced Akt activation increased the binding of themicrotubule-associated protein APC, the APC-binding protein end-binding protein 1 (EB1) and dynactin, a dynein activator complex, with microtubules. Depletion of Akt1 and Akt2 resulted in a disconnection of APC/EB1 and a decrease in bone-resorbing activity along with reduced sealing zone formation, both of which were recovered upon the addition ofLiCl, a GSK-3ss inhibitor. The Akt1 and Akt2 double knock-out mice exhibitedosteosclerosis due to reduced bone resorption. These findings indicate that Akt controls the bone-resorbing activity of osteoclasts by stabilizing microtubules via a regulationof the binding of microtubule associated proteins.

我们研究了Akt（磷脂酰肌醇3-激酶的下游效应子）在成熟破骨细胞的骨呈现活性中的作用。用特定的AKT抑制剂治疗破坏了密封区的形成，并降低了破骨细胞的骨质活性。丢失了正常的微管结构，AKT抑制剂降低了乙酰化小管蛋白的量，反映了稳定的微管，而腺病毒载体强迫AKT激活会导致相反的效果。强迫AKT激活增加了主题与蛋白APC的结合，APC结合蛋白终结蛋白1（EB1）和Dynactin（一种与微管）的结合（EB1）和Dynactin（dynaCtin）。 Akt1和Akt2的耗竭导致APC/EB1的断开连接，骨骼值的降低以及密封区的形成降低，这两者在添加后添加GSK-3SS抑制剂后均回收。由于骨吸收降低，AKT1和AKT2双敲除小鼠出现了骨硬化。这些发现表明，AKT通过调节微管相关蛋白的结合来稳定微管来控制破骨细胞的骨呈现活性。

项目成果

Regulation of bone resorption and sealing zone formation in osteoclasts occurs through protein kinase b-mediated microtubule stabilization

• DOI: 10.1002/jbmr.1844
• 发表时间: 2013-05-01
• 期刊: JOURNAL OF BONE AND MINERAL RESEARCH
• 影响因子: 6.2
• 作者: Matsumoto, Takumi;Nagase, Yuichi;Tanaka, Sakae
• 通讯作者: Tanaka, Sakae