Clinorotation prevents differentiation of rat myoblastic L6 cells in association with reduced NF-κB signaling
Clinorotation prevents differentiation of rat myoblastic L6 cells in association with reduced NF-κB signaling
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DOI：
10.1016/j.bbamcr.2004.09.013
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发表时间：
2005-03-22
影响因子：
5.1
通讯作者：
Kishi, K
中科院分区：
文献类型：
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作者：
Hirasaka, K;Nikawa, T;Kishi, K
在这项研究中，我们研究了三维（3D）-clinorotation，微重力的模拟模型，对大鼠成肌细胞L 6细胞的增殖/分化的影响。在三维旋转培养系统中，L 6细胞向肌管的分化受到显著干扰，尽管三维旋转对增殖没有影响。3D旋转还在mRNA水平上抑制肌生成标记蛋白如肌生成素和肌球蛋白重链（MHC）的表达。与这种减少的分化相关联，我们发现，与非旋转对照细胞相比，3D-旋转阻止了泛素化蛋白的积累。基于这些发现，我们集中在泛素依赖性降解的I κ B，肌生成抑制蛋白，阐明这种受损的分化的机制。L 6细胞中I κ B蛋白量的下降被旋转显著阻止，而非旋转细胞中的蛋白量沿着分化而下降。此外，3D旋转降低了L 6细胞中NF-κ B结合活性，并阻止了I κ B和泛素表达的Cos 7细胞中I κ B蛋白的泛素化。其他肌源性调节因子，如去泛素化酶，细胞周期蛋白E和氧，与分化受损的旋转。我们目前的研究结果表明，模拟微重力，如三维旋转可能会干扰骨骼肌细胞分化，至少在一定程度上，通过抑制NF-κ B B途径。(c)2004 Elsevier B. V.保留所有权利。
In this study, we examined effects of the three-dimensional (3D)-clinorotation, a simulated-model of microgravity, on proliferation/ differentiation of rat myoblastic L6 cells. Differentiation of L6 cells into myotubes was significantly disturbed in the 3D-clinorotation culture system, although the 3D-clinorotation had no effect on the proliferation. The 3D-clinorotation also suppressed the expression of myogenesis marker proteins, such as myogenin and myosin heavy chain (MHC), at the mRNA level. In association with this reduced differentiation, we found that the 3D-clinorotation prevented accumulation of ubiquitinated proteins, compared with non-rotation control cells. Based on these findings, we focused on the ubiquitin-dependent degradation Of I kappa B, a myogenesis inhibitory protein, to clarify the mechanism of this impaired differentiation. A decline in the amount Of I kappa B protein in L6 cells was significantly prevented by the rotation, while the amount of the protein in the non-rotated cells decreased along with the differentiation. Furthermore, the 3D-clinorotation reduced the NF-kappa B-binding activity in L6 cells and prevented the ubiquitination Of I kappa B proteins in the I kappa B- and ubiquitin-expressing Cos7 cells. Other myogenic regulatory factors, such as deubiquitinases, cyclin E and oxygen, were not associated with the differentiation impaired by the clinorotation. Our present results suggest that simulated microgravity such as the 3D-clinorotation may disturb skeletal muscle cell differentiation, at least in part, by inhibiting the NF-kappa B pathway. (c) 2004 Elsevier B.V. All rights reserved.