The LRRC8/VRAC anion channel facilitates myogenic differentiation of murine myoblasts by promoting membrane hyperpolarization
The LRRC8/VRAC anion channel facilitates myogenic differentiation of murine myoblasts by promoting membrane hyperpolarization
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DOI：
10.1074/jbc.ra119.008840
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发表时间：
2019-09-27
影响因子：
4.8
通讯作者：
Stauber, Tobias
中科院分区：
文献类型：
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作者：
Chen, Lingye;Becker, Thorsten M.;Stauber, Tobias
骨骼肌成肌细胞分化涉及复杂的信号网络，包括各种离子通道和转运蛋白的活性。一些K+和Ca 2+通道已被证明影响肌发生，但鲜为人知的作用，Cl-？相关进程中的通道。在这里，我们报告说，富含亮氨酸的重复包含家庭8（LRRC 8）/体积调节阴离子通道（VRAC）促进小鼠成肌细胞分化。所有LRRC 8亚基的异聚体VRAC的小鼠C2 C12成肌细胞的肌管形成过程中表达。药理学VRAC抑制剂、siRNA介导的必需VRAC亚基LRRC 8A的敲低或VRAC活性抑制LRRC 8A的过表达有效地降低了生肌转录因子肌细胞生成素的表达并抑制成肌细胞融合，同时不影响成肌细胞增殖。我们发现，抑制VRAC损害质膜超极化早期分化过程中。在以后的时间（诱导分化后超过6小时），VRAC抑制不再抑制成肌细胞分化，表明VRAC的上游K+通道激活的行为。因此，VRAC抑制阻止了通常发生在肌生成过程中的细胞内稳态Ca 2+水平的增加。我们的研究结果可以解释在LRRC 8A缺陷小鼠中观察到的骨骼肌束变薄的机制，并突出LRRC 8/VRAC阴离子通道在细胞分化中的重要性。
Skeletal muscle myoblast differentiation involves elaborate signaling networks, including the activity of various ion channels and transporters. Several K+ and Ca2+ channels have been shown to affect myogenesis, but little is known about roles of Cl-? channels in the associated processes. Here, we report that the leucine-rich repeat containing family 8 (LRRC8)/volume-regulated anion channel (VRAC) promotes mouse myoblast differentiation. All LRRC8 subunits of heteromeric VRAC were expressed during myotube formation of murine C2C12 myoblasts. Pharmacological VRAC inhibitors, siRNA-mediated knockdown of the essential VRAC subunit LRRC8A, or VRAC activity-suppressing overexpression of LRRC8A effectively reduced the expression of the myogenic transcription factor myogenin and suppressed myoblast fusion while not affecting myoblast proliferation. We found that inhibiting VRAC impairs plasma membrane hyperpolarization early during differentiation. At later times (more than 6 h after inducing differentiation), VRAC inhibition no longer suppressed myoblast differentiation, suggesting that VRAC acts upstream of K+ channel activation. Consequently, VRAC inhibition prevented the increase of intracellular steady-state Ca2+ levels that normally occurs during myogenesis. Our results may explain the mechanism for the thinning of skeletal muscle bundles observed in LRRC8A-deficient mice and highlight the importance of the LRRC8/VRAC anion channel in cell differentiation.