Mechanical Stretch Up-regulates MicroRNA-26a and Induces Human Airway Smooth Muscle Hypertrophy by Suppressing Glycogen Synthase Kinase-3β
Mechanical Stretch Up-regulates MicroRNA-26a and Induces Human Airway Smooth Muscle Hypertrophy by Suppressing Glycogen Synthase Kinase-3β
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DOI：
10.1074/jbc.m110.101147
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发表时间：
2010-09-17
影响因子：
4.8
通讯作者：
Boriek, Aladin M.
中科院分区：
文献类型：
--
作者：
Mohamed, Junaith S.;Lopez, Michael A.;Boriek, Aladin M.
气道平滑肌肥大是重症哮喘气道重塑的标志之一。目前已有几种人类疾病与微小RNA（miRNA）表达失调有关。miRNA是一类小的非编码RNA，在转录后水平对基因表达进行负调控。在此，我们确定miR - 26a是人类气道平滑肌细胞（HASMCs）的一种致肥大miRNA。我们发现拉伸可选择性诱导位于人类3号染色体3p21.3位点的miR - 26a转录。转录因子CCAAT增强子结合蛋白α（C/EBPα）在拉伸时通过转录机制直接激活miR - 26a的表达。此外，拉伸或强制表达miR - 26a会诱导HASMC肥大，而miR - 26敲低可逆转这种效应，表明miR - 26a是一个致肥大基因。我们确定糖原合成酶激酶 - 3β（GSK - 3β），一种抗肥大蛋白，是miR - 26a的靶基因。荧光素酶报告基因检测表明miR - 26a直接与GSK - 3β mRNA的3' - 非翻译重复序列相互作用。拉伸或强制表达miR - 26a会降低内源性GSK - 3β蛋白水平，进而诱导HASMC肥大。miR - 26敲低可逆转这种效应，表明miR - 26a诱导的肥大是通过其靶基因GSK - 3β发生的。总体而言，我们的研究首次揭示miR - 26a是一个机械敏感基因，并且在HASMC肥大的调控中起重要作用。
Airway smooth muscle hypertrophy is one of the hallmarks of airway remodeling in severe asthma. Several human diseases have been now associated with dysregulated microRNA (miRNA) expression. miRNAs are a class of small non-coding RNAs, which negatively regulate gene expression at the post-transcriptional level. Here, we identify miR-26a as a hypertrophic miRNA of human airway smooth muscle cells (HASMCs). We show that stretch selectively induces the transcription of miR-26a located in the locus 3p21.3 of human chromosome 3. The transcription factor CCAAT enhancer-binding protein alpha (C/EBP alpha) directly activates miR-26a expression through the transcriptional machinery upon stretch. Furthermore, stretch or enforced expression of miR-26a induces HASMC hypertrophy, and miR-26 knockdown reverses this effect, suggesting that miR-26a is a hypertrophic gene. We identify glycogen synthase kinase-3 beta (GSK-3 beta), an anti-hypertrophic protein, as a target gene of miR-26a. Luciferase reporter assays demonstrate that miR-26a directly interact with the 3'-untranslated repeat of the GSK-3 beta mRNA. Stretch or enforced expression of miR-26a attenuates the endogenous GSK-3 beta protein levels followed by the induction of HASMC hypertrophy. miR-26 knockdown reverses this effect, suggesting that miR-26a-induced hypertrophy occurs via its target gene GSK-3 beta. Overall, as a first time, our study unveils that miR-26a is a mechanosensitive gene, and it plays an important role in the regulation of HASMC hypertrophy.