Department of Respiratory, The Second People's Hospital of Lanzhou City, Lanzhou City, Gansu Province, People's Republic of China.
Department of Interventional Medicine and Oncology, The Affiliated Hospital of Northwest Minzu University, Lanzhou City, Gansu Province, People's Republic of China.
Int J Chron Obstruct Pulmon Dis. 2020 Dec 31;15:3407-3416. doi: 10.2147/COPD.S278553. eCollection 2020.
Chronic obstructive pulmonary disease (COPD) is an age-related disease, and its incidence rate is increasing every year. MicroRNAs (miRNAs) play critical roles in the COPD process and function as key biomarkers or potential therapeutic targets for patients with COPD. However, the potential roles and functional effects of miR-218 in COPD remain undefined.
The expression levels of miR-218 and bromodomain protein 4 (BRD4) were assessed by real-time quantitative polymerase chain reaction (RT-qPCR) or Western blot, respectively. In addition, a COPD cell model was established using cigarette smoke extract (CSE) in bronchial epithelial cell line (BEAS-2B). Enzyme-linked immunosorbent assay (ELISA) kit was applied to measure the concentrations of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8) in cell supernatants of BEAS-2B cells. Moreover, cell apoptosis was examined by flow cytometry assay. The association relationship between miR-218 and BRD4 was confirmed by dual-luciferase reporter and RNA immunoprecipitation assay.
MiR-218 was downregulated in COPD and CSE-induced BEAS-2B cells, and it was positively correlated with forced expiratory volume in 1 second (FEV1) % in COPD patients. Mechanically, overexpression of miR-218 or knockdown of BRD4 mitigated apoptosis and inflammation in BEAS-2B cells induced by CSE. Additionally, overexpression of BRD4 weakened the miR-218-mediated effects on CSE-induced BEAS-2B cells.
Overexpression of miR-218 inhibited CSE-induced apoptosis and inflammation in BEAS-2B cells by targeting BRD4 expression.
慢性阻塞性肺疾病（COPD）是一种与年龄相关的疾病，其发病率逐年上升。微小 RNA（miRNA）在 COPD 过程中发挥着关键作用，可作为 COPD 患者的关键生物标志物或潜在治疗靶点。然而，miR-218 在 COPD 中的潜在作用和功能影响仍未确定。
通过实时定量聚合酶链反应（RT-qPCR）或 Western blot 分别评估 miR-218 和溴结构域蛋白 4（BRD4）的表达水平。此外，采用香烟烟雾提取物（CSE）在支气管上皮细胞系（BEAS-2B）中建立 COPD 细胞模型。酶联免疫吸附测定（ELISA）试剂盒用于测定 BEAS-2B 细胞上清液中肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）和白细胞介素-8（IL-8）的浓度。此外，通过流式细胞术检测细胞凋亡。通过双荧光素酶报告和 RNA 免疫沉淀测定证实 miR-218 和 BRD4 之间的关联关系。
miR-218 在 COPD 和 CSE 诱导的 BEAS-2B 细胞中下调，并且与 COPD 患者的 1 秒用力呼气量（FEV1）%呈正相关。在机制上，过表达 miR-218 或敲低 BRD4 可减轻 CSE 诱导的 BEAS-2B 细胞凋亡和炎症。此外，BRD4 的过表达削弱了 miR-218 对 CSE 诱导的 BEAS-2B 细胞的作用。
过表达 miR-218 通过靶向 BRD4 表达抑制 CSE 诱导的 BEAS-2B 细胞凋亡和炎症。
