Coordination of microtubules and the actin cytoskeleton is important in osteoclast function, but calcitonin disrupts sealing zones without affecting microtubule networks
Coordination of microtubules and the actin cytoskeleton is important in osteoclast function, but calcitonin disrupts sealing zones without affecting microtubule networks
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DOI：
10.1016/j.bone.2006.04.010
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发表时间：
2006-10-01
期刊：
影响因子：
4.1
通讯作者：
Takahashi, N.
中科院分区：
文献类型：
--
作者：
Okumura, S.;Mizoguchi, T.;Takahashi, N.
骨吸收破骨细胞形成密封区和朝向骨表面的褶皱边界。密封区由 F-肌动蛋白点的环状排列组成，并围绕褶皱边界，质子从该边界分泌到骨表面。破骨细胞中的液泡型质子 ATP 酶（V-ATP 酶）是一种负责质子分泌的皱边边界相关酶。我们研究了破骨细胞中微管和肌动蛋白细胞骨架之间的相互作用。共聚焦显微镜观察发现，玻璃盖玻片、牙本质切片和骨盘（TM）上的破骨细胞形成了F-肌动蛋白点的环状结构，并且微管重叠在F-肌动蛋白点的顶部。在牙本质上培养的破骨细胞在48小时内形成吸收坑。用细胞松弛素 D（一种 F-肌动蛋白解聚试剂）处理破骨细胞，会引起玻璃上破骨细胞微管的扰动，并以剂量依赖性和可逆的方式抑制其在牙本质上的小坑形成活性。相反，诺考达唑（一种微管解聚试剂）以剂量依赖性和可逆的方式破坏密封区并抑制破骨细胞的成坑活性。 V-ATP酶显示出定位于破骨细胞密封区内的趋势。用降钙素处理破骨细胞会在 60 分钟内诱导密封区的破坏和 V-ATP 酶分散到细胞质的整个区域。即使有降钙素存在，破骨细胞中的微管网络在 60 分钟内也保持不变。这些结果表明，肌动蛋白细胞骨架和微管的协调对于破骨细胞的功能很重要，但降钙素选择性地影响肌动蛋白细胞骨架并诱导V-ATP酶的分散，而不引起微管的显着变化。 (c) 2006 Elsevier Inc. 保留所有权利。
Bone-resorbing osteoclasts form sealing zones and ruffled borders toward the bone surface. The sealing zone consists of a ring-like alignment of F-actin dots and surrounds the ruffled border, from which protons are secreted into the bone surface. Vacuolar-type proton ATPase (V-ATPase) in osteoclasts is a ruffled border-associated enzyme responsible for the proton secretion. We studied the interaction between microtubules and the actin cytoskeleton in osteoclasts. Confocal microscopic observation revealed that osteoclasts on glass coverslips, dentine slices and Osteologic (TM) discs formed the ring-like structure of F-actin dots, and microtubules overlapped the top of the F-actin dots. Osteoclasts cultured on dentine formed resorption pits within 48 h. The treatment of osteoclasts with cytochalasin D, an F-actin-depolymerizing reagent, induced perturbation of the microtubules in osteoclasts on glass and inhibited their pit-forming activity on dentine in a dose-dependent and reversible manner. Conversely, nocodazole, a microtubule-depolymerizing reagent, disrupted sealing zones and inhibited pit-forming activity of osteoclasts in a dose-dependent and reversible manner. V-ATPase showed a tendency to be localized inside sealing zones in osteoclasts. Treatment of osteoclasts with calcitonin induced both disruption of sealing zones and dispersion of V-ATPase to the whole area of the cytoplasm within 60 min. The microtubule networks in osteoclasts remained unchanged for 60 min even in the presence of calcitonin. These results suggest that coordination of the actin cytoskeleton and microtubules is important in the function of osteoclasts, but calcitonin selectively affects the actin cytoskeleton and induces the dispersion of V-ATPase without causing significant changes in the microtubules. (c) 2006 Elsevier Inc. All rights reserved.