Nuclear miR-30b-5p suppresses TFEB-mediated lysosomal biogenesis and autophagy
Nuclear miR-30b-5p suppresses TFEB-mediated lysosomal biogenesis and autophagy
复制标题
核 miR-30b-5p 抑制 TFEB 介导的溶酶体生物发生和自噬
DOI：
10.1038/s41418-020-0602-4
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发表时间：
2020-08-06
影响因子：
12.4
通讯作者：
Ren, Jin
中科院分区：
文献类型：
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作者：
Guo, Huijie;Pu, Mei;Ren, Jin
溶酶体是一种关键的细胞器，负责降解蛋白质和受损的细胞器以维持细胞内稳态。转录因子EB（TFEB）是调控溶酶体生物发生和自噬的主要转录因子。在饥饿等外部刺激下，去磷酸化的TFEB转运进入细胞核，特异性地识别并结合自噬和溶酶体生物发生相关基因启动子上的协同溶酶体表达和调控（CLEAR）元件。TFEB在细胞核中的功能受到精细调控，但其分子机制尚未完全阐明。在本研究中，我们发现miR - 30b - 5p（一种已知通过在细胞质中进行转录后调控来调节一系列基因的小RNA）转运进入细胞核，结合CLEAR元件，抑制TFEB依赖性下游基因的转录，进而抑制溶酶体生物发生和自噬通量；同时，通过CRISPR/Cas9技术敲除内源性miR - 30b - 5p显著增加了TFEB介导的反式激活，导致自噬和溶酶体生物发生相关基因的表达增加。在小鼠肝脏中过表达miR - 30b - 5p显示溶酶体生物发生和自噬减少。这些体外和体内数据表明，miR - 30b - 5p可能通过结合细胞核中的CLEAR元件抑制TFEB依赖性反式激活，从而调控溶酶体生物发生和自噬。这种核内微小RNA调控基因转录的新机制有助于进一步阐明微小RNA在溶酶体生理功能中的作用，并有助于理解异常自噬相关疾病的发病机制。
Lysosome is a crucial organelle in charge of degrading proteins and damaged organelles to maintain cellular homeostasis. Transcription factor EB (TFEB) is the master transcription factor regulating lysosomal biogenesis and autophagy. Under external stimuli such as starvation, dephosphorylated TFEB transports into the nucleus to specifically recognize and bind to the coordinated lysosomal expression and regulation (CLEAR) elements at the promotors of autophagy and lysosomal biogenesis-related genes. The function of TFEB in the nucleus is fine regulated but the molecular mechanism is not fully elucidated. In this study, we discovered that miR-30b-5p, a small RNA which is known to regulate a series of genes through posttranscriptional regulation in the cytoplasm, was translocated into the nucleus, bound to the CLEAR elements, suppressed the transcription of TFEB-dependent downstream genes, and further inhibited the lysosomal biogenesis and the autophagic flux; meanwhile, knocking out the endogenous miR-30b-5p by CRISPR/Cas9 technique significantly increased the TFEB-mediated transactivation, resulting in the increased expression of autophagy and lysosomal biogenesis-related genes. Overexpressing miR-30b-5p in mice livers showed a decrease in lysosomal biogenesis and autophagy. These in vitro and in vivo data indicate that miR-30b-5p may inhibit the TFEB-dependent transactivation by binding to the CLEAR elements in the nucleus to regulate the lysosomal biogenesis and autophagy. This novel mechanism of nuclear miRNA regulating gene transcription is conducive to further elucidating the roles of miRNAs in the lysosomal physiological functions and helps to understand the pathogenesis of abnormal autophagy-related diseases.