MicroRNA-27a Regulates Beta Cardiac Myosin Heavy Chain Gene Expression by Targeting Thyroid Hormone Receptor β1 in Neonatal Rat Ventricular Myocytes
MicroRNA-27a Regulates Beta Cardiac Myosin Heavy Chain Gene Expression by Targeting Thyroid Hormone Receptor β1 in Neonatal Rat Ventricular Myocytes
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DOI：
10.1128/mcb.00581-10
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发表时间：
2011-02-01
影响因子：
5.3
通讯作者：
Kimura, Takeshi
中科院分区：
文献类型：
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作者：
Nishi, Hitoo;Ono, Koh;Kimura, Takeshi
microRNAs（miRNAs）是一类非编码小分子RNA，是基因表达的负调控因子，在心脏基因调控中起重要作用。为了研究miRNA在心肌肌球蛋白重链（MHC）基因的两种亚型（α-和β-MHC）表达中的作用，α-和β-MHC调节心肌收缩力，使用慢病毒介导的小干扰RNA（siRNA）下调新生大鼠心室肌细胞（NRVM）中的内源性miRNA，并检测MHC表达水平。结果表明，Dicer siRNA可同时下调内源性miRNAs和β-MHC基因，但不下调α-MHC基因，提示特异性miRNAs可上调β-MHC基因。在19种选择的miRNA中，发现miR-27 a最强烈地上调β-MHC基因，但不上调α-MHC。此外，内源性miR-27 a的沉默下调了β-MHC蛋白。通过使用TargetScan的生物信息学筛选，我们确定了甲状腺激素受体β 1（TR β 1），其负调节β-MHC转录，作为miR-27 a的靶点。此外，已证明miR-27 a通过甲状腺激素信号传导调节β-MHC基因调控，并在小鼠胚胎干（ES）细胞分化期间或在与β-MHC基因上调相关的肥大心脏中上调。这些发现表明，miR-27 a通过靶向心肌细胞中的TR β 1来调节β-MHC基因表达。
MicroRNAs (miRNAs), small noncoding RNAs, are negative regulators of gene expression and play important roles in gene regulation in the heart. To examine the role of miRNAs in the expression of the two isoforms of the cardiac myosin heavy chain (MHC) gene, alpha- and beta-MHC, which regulate cardiac contractility, endogenous miRNAs were downregulated in neonatal rat ventricular myocytes (NRVMs) using lentivirus-mediated small interfering RNA (siRNA) against Dicer, an essential enzyme for miRNA biosynthesis, and MHC expression levels were examined. As a result, Dicer siRNA could downregulate endogenous miRNAs simultaneously and the beta-MHC gene but not alpha-MHC, which implied that specific miRNAs could upregulate the beta-MHC gene. Among 19 selected miRNAs, miR-27a was found to most strongly upregulate the beta-MHC gene but not alpha-MHC. Moreover, beta-MHC protein was downregulated by silencing of endogenous miR-27a. Through a bioinformatics screening using TargetScan, we identified thyroid hormone receptor beta 1 (TR beta 1), which negatively regulates beta-MHC transcription, as a target of miR-27a. Moreover, miR-27a was demonstrated to modulate beta-MHC gene regulation via thyroid hormone signaling and to be upregulated during the differentiation of mouse embryonic stem (ES) cells or in hypertrophic hearts in association with beta-MHC gene upregulation. These findings suggested that miR-27a regulates beta-MHC gene expression by targeting TR beta 1 in cardiomyocytes.