Continuous exposure of isoprenaline inhibits myoblast differentiation and fusion through PKA/ERK1/2-FOXO1 signaling pathway
Continuous exposure of isoprenaline inhibits myoblast differentiation and fusion through PKA/ERK1/2-FOXO1 signaling pathway
复制标题
持续暴露异丙肾上腺素通过 PKA/ERK1/2-FOXO1 信号通路抑制成肌细胞分化和融合
DOI：
10.1186/s13287-019-1160-x
复制
发表时间：
2019-02-28
影响因子：
7.5
通讯作者：
Tang, Jun-ming
中科院分区：
文献类型：
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作者：
Chen, Shao-juan;Yue, Jing;Tang, Jun-ming
目的研究交感神经活性是否参与肌卫星细胞分化和成肌细胞融合的过程，方法和结果采用免疫组化和Western blot分析，发现C2 C12细胞表达1和2-肾上腺素能受体（AdR）。与增殖期细胞相比，分化的卫星细胞表现出2-AdR的表达增加。持续暴露于异丙肾上腺素（ISO）、α-AdR激动剂、延迟的C2 C12细胞分化和成肌细胞融合，呈时间和剂量依赖性。ISO还增加了短肌管数量，同时减少了长肌管数量，这与MyHC 1、MyHC 2a和MyHC 2x表达的较大减少一致。此外，持续暴露于ISO后，PKA RI/RII比值逐渐降低，PKA RI激活剂可有效逆转ISO对C2 C12细胞分化和成肌细胞融合的影响，而PKA抑制剂H-89则使ISO的作用恶化。连续单剂量ISO增加C2 C12细胞中1-AdR的表达。更重要的是，细胞表现出增强的磷酸化ERK 1/2水平，导致磷酸化2-AdR水平升高而2-AdR水平降低，并且ERK 1/2抑制剂可以消除这种特异性作用。此外，持续暴露ISO诱导FOXO 1核转位，并增加FOXO 1在核提取物中的水平，同时降低pAKT，p-p38 MAPK和pFOXO 1水平。相反，阻断ERK 12信号通路可部分阻断ISO对AKT、p38 MAPK和FOXO 1信号通路的影响，从而部分恢复C2 C12细胞的分化和成肌细胞融合，导致中等肌管数量增加，同时沿着MyHC 1和MyHC 2a表达增加。通过PKA-ERK 1/2-FOXO 1信号通路，与2-AdR水平降低和1-AdR水平升高相关。
AimThe objective of this study is to determine if exuberant sympathetic nerve activity is involved in muscle satellite cell differentiation and myoblast fusion.Methods and resultsBy using immunoassaying and western blot analyses, we found that 1 and 2-adrenergic receptors (AdR) were expressed in C2C12 cells. The differentiated satellite cells exhibited an increased expression of 2-AdR, as compared with the proliferating cells. Continuous exposure of isoprenaline (ISO), a -AdR agonist, delayed C2C12 cell differentiation, and myoblast fusion in time- and dose-dependent manner. ISO also increased short myotube numbers while decreasing long myotube numbers, consistent with the greater reduction in MyHC1, MyHC2a, and MyHC2x expression. Moreover, continuous exposure of ISO gradually decreased the ratio of PKA RI/RII, and PKA RI activator efficiently reversed the ISO effect on C2C12 cell differentiation and myoblast fusion while PKA inhibitor H-89 deteriorated the effects. Continuous single-dose ISO increased 1-AdR expression in C2C12 cells. More importantly, the cells showed enhanced phospho-ERK1/2 levels, resulting in increasing phospho-2-AdR levels while decreasing 2-AdR levels, and the specific effects could be abolished by ERK1/2 inhibitor. Furthermore, continuous exposure of ISO induced FOXO1 nuclear translocation and increased the levels of FOXO1 in nuclear extracts while reducing pAKT, p-p38MAPK, and pFOXO1 levels. Conversely, blockade of ERK1/2 signaling partially abrogated ISO effects on AKT, p38MAPK, and FOXO1signaling, which partially restored C2C12 cell differentiation and myoblast fusion, leading to an increase in the numbers of medium myotube along with the increased expression of MyHC1 and MyHC2a.ConclusionContinuous exposure of ISO impedes satellite cell differentiation and myoblast fusion, at least in part, through PKA-ERK1/2-FOXO1 signaling pathways, which were associated with the reduced 2-AdR and increased 1-AdR levels.