Liu Fen, Shang Yun-Xiao
Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China.
Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China.
Int Immunopharmacol. 2020 Mar 3;82:106333. doi: 10.1016/j.intimp.2020.106333.
Allergic asthma is a chronic inflammatory airway disease involving airway remodeling. The histone deacetylase sirtuin6 (SIRT6) has protective effects in cardiac and liver fibrosis; however, its role in airway remodeling is unclear. In this study, we investigated the expression of SIRT6 in a rat model of airway remodeling and observed its effects on the epithelial-mesenchymal transition (EMT) in human bronchial epithelial 16HBE cells. Sprague-Dawley rats were sensitized and challenged with ovalbumin to induce airway remodeling or with phosphate-buffered saline as a control for different periods. Morphological changes, cell counts in the bronchoalveolar lavage fluid, and SIRT6 expression were assessed. 16HBE cells were transfected with plasmids to silence or overexpress SIRT6. Western blotting, quantitative polymerase chain reaction, Transwell assays, and cell proliferation assays were performed to examine the transforming growth factor (TGF)-β1-induced changes in EMT indicators and EMT-related cell behaviors. SIRT6 expression was upregulated in bronchial epithelial cells from rats with airway remodeling and in TGF-β1-treated 16HBE cells. SIRT6 overexpression affected TGF-β1-induced changes in EMT markers and EMT-like cell behaviors. In particular, SIRT6 overexpression alleviated the reduction in E-cadherin and the increases in N-cadherin, vimentin, alpha-smooth muscle actin, and metalloproteinase-9 levels in TGF-β1-treated 16HBE cells. Forced expression of SIRT6 also decreased the rates of cell migration and proliferation, reduced activation of phosphorylated Smad3 induced by TGF-β1 treatment, suppressed the acetylation level at histone H3K9, and inhibited the transcriptional activity of the c-Jun promotor. These results suggested that SIRT6 expression is upregulated during airway remodeling and modulates EMT in bronchial epithelial cells targeting Smad3 and c-Jun, highlighting a new therapeutic candidate for improving airway remodeling in asthma.
过敏性哮喘是一种涉及气道重塑的慢性炎症性气道疾病。组蛋白去乙酰化酶沉默调节蛋白6（SIRT6）在心脏和肝纤维化中具有保护作用；然而，其在气道重塑中的作用尚不清楚。在本研究中，我们调查了SIRT6在气道重塑大鼠模型中的表达，并观察了其对人支气管上皮16HBE细胞上皮-间质转化（EMT）的影响。将Sprague-Dawley大鼠用卵清蛋白致敏并激发以诱导气道重塑，或用磷酸盐缓冲盐水作为不同时期的对照。评估形态学变化、支气管肺泡灌洗液中的细胞计数和SIRT6表达。用质粒转染16HBE细胞以沉默或过表达SIRT6。进行蛋白质免疫印迹法、定量聚合酶链反应、Transwell试验和细胞增殖试验，以检测转化生长因子（TGF）-β1诱导的EMT指标变化和EMT相关细胞行为。气道重塑大鼠的支气管上皮细胞和TGF-β1处理的16HBE细胞中SIRT6表达上调。SIRT6过表达影响TGF-β1诱导的EMT标志物变化和类EMT细胞行为。特别是，SIRT6过表达减轻了TGF-β1处理的16HBE细胞中E-钙黏蛋白的减少以及N-钙黏蛋白、波形蛋白、α-平滑肌肌动蛋白和金属蛋白酶-9水平的增加。SIRT6的强制表达还降低了细胞迁移和增殖率，降低了TGF-β1处理诱导的磷酸化Smad3的激活，抑制了组蛋白H3K9的乙酰化水平，并抑制了c-Jun启动子的转录活性。这些结果表明，在气道重塑过程中SIRT6表达上调，并通过靶向Smad3和c-Jun调节支气管上皮细胞中的EMT，突出了一种改善哮喘气道重塑的新治疗候选物。
