Nakamura I, Takahashi N, Sasaki T, Tanaka S, Udagawa N, Murakami H, Kimura K, Kabuyama Y, Kurokawa T, Suda T
Department of Biochemistry, School of Dentistry, Showa University, Tokyo, Japan.
FEBS Lett. 1995 Mar 13;361(1):79-84. doi: 10.1016/0014-5793(95)00153-z.
The biological role of phosphatidylinositol (PI)-3 kinase was examined in osteoclast-like multinucleated cells (OCLs) formed in co-cultures of mouse osteoblastic cells and bone marrow cells. The expression of PI-3 kinase in OCLs was confirmed by Western blot analysis. Wortmannin (WT), a specific inhibitor of PI-3 kinase, inhibited PI-3 kinase activity in OCLs both in vitro and in vivo. WT also inhibited pit-forming activity on dentine slices and disrupted a ringed structure of F-actin-containing dots (an actin ring) in OCLs in a dose-dependent manner. The inhibitory profiles of WT for pit and actin ring formation were similar to that for PI-3 kinase activity in OCLs. Electron microscopic analysis revealed that OCLs treated with WT did not form ruffled borders. Instead, numerous electron lucent vacuoles of differing sizes were found throughout the cytoplasm. These results suggest that PI-3 kinase is important in osteoclastic bone resorption.
在小鼠成骨细胞与骨髓细胞共培养形成的破骨细胞样多核细胞（OCLs）中，研究了磷脂酰肌醇（PI）-3激酶的生物学作用。通过蛋白质免疫印迹分析证实了PI-3激酶在OCLs中的表达。PI-3激酶的特异性抑制剂渥曼青霉素（WT）在体外和体内均抑制了OCLs中的PI-3激酶活性。WT还以剂量依赖的方式抑制了牙本质切片上的陷窝形成活性，并破坏了OCLs中含F-肌动蛋白的点（肌动蛋白环）的环状结构。WT对陷窝和肌动蛋白环形成的抑制作用与对OCLs中PI-3激酶活性的抑制作用相似。电子显微镜分析显示，用WT处理的OCLs未形成皱褶缘。相反，在整个细胞质中发现了许多大小不同的电子透明空泡。这些结果表明，PI-3激酶在破骨细胞性骨吸收中起重要作用。
