BACKGROUND Transforming growth factor-β1 (TGF-β1)-in-duced proliferation of airway smooth muscle cells plays critical roles in the development of airway remodeling. Six1 (sine oculis homeobox homolog 1) has been demonstrated to be involved in airway inflammation and remodeling in asthmatic mice. OBJECTIVES The aim of this work was to investigate the potential role of miR-204-5p in the proliferation and extracellular matrix (ECM) production of airway smooth muscle cells in asthma. METHODS Real-time PCR was used to measure the expression of miR-204-5p in asthmatic airway smooth muscle cells. Cell viability and apoptosis were detected to evaluate the effect of miR-204-5p on airway smooth muscle cells. Dual-luciferase reporter experiments were applied to identify the target genes of miR-204-5p. RESULTS MiR-204-5p was downregulated notably in asthmatic airway smooth muscle cells as well as cells stimulated with TGF-β1. Overexpression of miR-204-5p markedly suppressed the TGF-β1-induced proliferation of airway smooth muscle cells and the deposition of ECM, whereas the inhibition of miR-204-5p significantly enhanced the proliferation of airway smooth muscle cells and upregulated the level of fibronectin and collagen III. Furthermore, subsequent analyses demonstrated that Six1 was a direct target of miR-204-5p, and Western blot further indicated that miR-204-5p negatively regulated the expression of Six1. Most importantly, the restoration of Six1 expression reversed the inhibitory effect of miR-204-5p on TGF-β1-induced proliferation and ECM production. CONCLUSIONS MiR-204-5p inhibits TGF-β1-in-duced proliferation and ECM production of airway smooth muscle cells by regulating Six1, identifying a potential therapeutic target for preventing airway remodeling in asthma.

中文翻译：

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MiR-204-5p通过调节哮喘中的Six1抑制转化生长因子-β1诱导的气道平滑肌细胞增殖和细胞外基质产生。

背景技术转化生长因子-β1（TGF-β1）诱导的气道平滑肌细胞增殖在气道重塑发展中起关键作用。Six1（正弦球同源盒同源物1）已被证明与哮喘小鼠的气道炎症和重塑有关。目的这项研究的目的是研究miR-204-5p在哮喘气道平滑肌细胞增殖和细胞外基质（ECM）产生中的潜在作用。方法采用实时荧光定量PCR检测miR-204-5p在哮喘气道平滑肌细胞中的表达。检测细胞活力和凋亡以评估miR-204-5p对气道平滑肌细胞的作用。应用双重荧光素酶报告基因实验鉴定miR-204-5p的靶基因。结果在哮喘气道平滑肌细胞和TGF-β1刺激的细胞中，MiR-204-5p明显下调。miR-204-5p的过表达显着抑制了TGF-β1诱导的气道平滑肌细胞的增殖和ECM的沉积，而抑制miR-204-5p则显着增强了气道平滑肌细胞的增殖并上调了其水平。纤连蛋白和胶原蛋白III。此外，随后的分析表明，Six1是miR-204-5p的直接靶标，而Western印迹进一步表明，miR-204-5p负调节了Six1的表达。最重要的是，Six1表达的恢复逆转了miR-204-5p对TGF-β1诱导的增殖和ECM产生的抑制作用。