MiR-20a and miR-106b negatively regulate autophagy induced by leucine deprivation via suppression of ULK1 expression in C2C12 myoblasts
MiR-20a and miR-106b negatively regulate autophagy induced by leucine deprivation via suppression of ULK1 expression in C2C12 myoblasts
复制标题
MiR-20a 和 miR-106b 通过抑制 C2C12 成肌细胞中的 ULK1 表达负向调节亮氨酸剥夺诱导的自噬
DOI：
10.1016/j.cellsig.2012.07.001
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发表时间：
2012-11-01
影响因子：
4.8
通讯作者：
Yan, Xianghua
中科院分区：
文献类型：
--
作者：
Wu, Hao;Wang, Fengli;Yan, Xianghua
自噬是一个进化上保守的过程，负责通过溶酶体机制降解和回收细胞质组分。它在细胞内环境稳定、细胞生长和生物体发育中起着重要作用。此外，自噬异常与许多人类病理生理学有关。新出现的证据已经将亮氨酸剥夺诱导的蛋白质分解与自噬联系起来，但是在这个过程中控制自噬活性的潜在机制还没有完全理解。在这里，我们证明了miR-17 microRNA家族的两个成员，miR-20 a和miR-106 b。可能通过抑制C2 C12成肌细胞中ULK 1的表达参与调节亮氨酸剥夺诱导的自噬。我们发现亮氨酸剥夺通过抑制其转录因子c-Myc下调miR-20 a和miR-106 b的表达。我们发现自噬基因ULK 1是miR-20 a和miR-106 b的细胞靶点。用miR-20 a或miR-106 b模拟物处理C2 C12细胞降低了内源性ULK 1蛋白水平。双荧光素酶报告基因分析证实ULK 1的3' UTR中的miRNA结合序列有助于miR-20 a和miR-106 b对ULK 1表达的调节。此外，通过miR-20 a或miR-106 b模拟物抑制ULK 1表达减弱了由亮氨酸剥夺诱导的自噬激活，而在C2 C12细胞中通过特异性miR-20 a或miR-106 b抑制内源性miR-20 a或miR-106 b显示出正常的自噬活性。总之，我们的数据表明，miR-20 a和miR-106 b通过靶向ULK 1调节C2 C12细胞中亮氨酸剥夺诱导的自噬。(C)2012 Elsevier Inc. All rights reserved.
Autophagy is an evolutionarily conserved process responsible for degradation and recycling of cytoplasmic components through the lysosomal machinery. It has been proved to play pivotal roles in cellular homeostasis, cell growth and organism development. Moreover, abnormalities of autophagy have been linked to numerous human pathophysiologies. Emerging evidence has linked leucine deprivation induced protein breakdown to autophagy, but the underlying mechanisms controlling autophagic activity in this process are not fully understood. Here, we demonstrate that two members of the miR-17 microRNA family, miR-20a and miR-106b. may participate in regulating leucine deprivation induced autophagy via suppression of ULK1 expression in C2C12 myoblasts. We showed that leucine deprivation downregulated miR-20a and miR-106b expression via suppression of their transcription factor c-Myc. We discovered the essential autophagy gene ULK1 as cellular target of miR-20a and miR-106b. Treatment of C2C12 cells with the miR-20a or miR-106b mimic decreased the endogenous ULK1 protein levels. Dual luciferase reporter assay confirmed that the miRNA binding sequences in the 3' UTR of ULK1 contribute to the modulation of ULK1 expression by miR-20a and miR-106b. Furthermore, inhibition of ULK1 expression by the miR-20a or miR-106b mimic blunted activation of autophagy induced by leucine deprivation, while suppression of endogenous miR-20a or miR-106b by specific antagomir in C2C12 cells showed normal autophagic activity. Altogether, our data demonstrated that miR-20a and miR-106b regulated autophagy induced by leucine deprivation in C2C12 cells via targeting ULK1. (C) 2012 Elsevier Inc. All rights reserved.