Cytoskeleton/stretch-activated ion channel interaction regulates myogenic differentiation of skeletal myoblasts
Cytoskeleton/stretch-activated ion channel interaction regulates myogenic differentiation of skeletal myoblasts
复制标题
DOI：
10.1002/jcp.20936
复制
发表时间：
2007-05-01
影响因子：
5.6
通讯作者：
Zecchi-Orlandini, Sandra
中科院分区：
文献类型：
--
作者：
Formigli, Lucia;Meacci, Elisabetta;Zecchi-Orlandini, Sandra
在本研究中，我们研究了应力纤维（SF）和拉伸激活通道（SAC）之间的功能相互作用，及其在存在或不存在磷酸鞘氨醇的情况下转为分化培养诱导的成肌细胞分化调节中的可能作用。结果发现，在分化 C2C12 成肌细胞时，SF 形成和 SAC 激活之间存在明显的时间相关性。用特异性 Rho 激酶抑制剂 Y-27632 抑制肌动蛋白聚合，显着降低这些细胞中的 SAC 敏感性，表明 Rho 依赖性肌动蛋白重塑在通道开放调节中的作用。通过联合共聚焦免疫荧光、生化和电生理学分析判断，细胞骨架/SAC 功能相关性的改变对 C2C12 细胞的肌原性分化也有有害影响。事实上，用 Y-27632 或 DHCB（一种肌动蛋白破坏剂）治疗可抑制生肌标记物（肌细胞生成素和肌节蛋白）的表达和成肌细胞-肌管转变。通道阻滞剂 GdCl3 的治疗也影响这些细胞的肌生成。事实上，它损害了成肌细胞表型成熟（即降低了α-肌节肌动蛋白和骨骼肌球蛋白的表达以及肌酸激酶的活性），但没有改变启动子活性和肌细胞生成素的蛋白质表达水平。这项研究的结果与细胞骨架重塑对于肌肉分化至关重要的一般观点一致，描述了一种新的途径，通过该途径，SF 的形成及其收缩，对质膜产生机械张力，激活 SAC 并触发 Ca2+ 依赖性信号，从而影响成肌细胞的表型成熟。
In the present study, we investigated the functional interaction between stress fibers (SFs) and stretch-activated channels (SACs) and its possible role in the regulation of myoblast differentiation induced by switch to differentiation culture in the presence or absence of sphingosine I-phosphate. It was found that there was a clear temporal correlation between SF formation and SAC activation in differentiating C2C12 myoblasts. Inhibition of actin polymerization with the specific Rho kinase inhibitor Y-27632, significantly decreased SAC sensitivity in these cells, suggesting a role for Rho-dependent actin remodeling in the regulation of the channel opening. The alteration of cytoskeletal/SAC functional correlation had also deleterious effects on myogenic differentiation of C2C12 cells as judged by combined confocal immunofluorescence, biochemical and electrophysiological analyses. Indeed, the treatment with Y-27632 or with DHCB, an actin disrupting agent, inhibited the expression of the myogenic markers (myogenin and sarcomeric proteins) and myoblast-myotube transition. The treatment with the channel blocker, GdCl3, also affected myogenesis in these cells. It impaired, in fact, myoblast phenotypic maturation (i.e., reduced the expression of a-sarcomeric actin and skeletal myosin and the activity of creatine kinase) but did not modify promoter activity and protein expression levels of myogenin. The results of this study, together with being in agreement with the general idea that cytoskeletal remodeling is essential for muscle differentiation, describe a novel pathway whereby the formation of SFs and their contraction, generate a mechanical tension to the plasma membrane, activate SACs and trigger Ca2+-dependent signals, thus influencing the phenotypic maturation of myoblasts.