Lei Zhenwu, Guo Hui, Zou Shenchun, Jiang Jing, Kui Yuchuan, Song Jie
Department of Intervention, Qinghai University Affiliated Hospital, Xining, Qinghai 810000, P.R. China.
Department of Respiratory Medicine, Zaozhuang Mining Group Central Hospital, Zaozhuang, Shandong 277000, P.R. China.
Exp Ther Med. 2021 Jan;21(1):60. doi: 10.3892/etm.2020.9492. Epub 2020 Nov 19.
Chronic obstructive pulmonary disease (COPD) has become a significant public health risk. Long non-coding RNAs (lncRNAs) have been identified as important factors involved in the proliferation, apoptosis and inflammatory cytokine expression of lung cells. Peripheral blood samples from 66 subjects (18 non-smokers, 24 smokers without COPD and 28 smokers with COPD) and HBE135-E6E7 cell treated with cigarette smoke extract (CSE) or not were used as the research object. The aim of the present study was to investigate the underlying mechanism of lncRNA maternally expressed gene 3 (MEG3) in COPD. Following transfection with microRNA (miR)-149-3p mimics, miR-negative control mimics, miR-149-3p inhibitor, miR-negative control inhibitor, small interfering (si)RNA targeting MEG3 (si-MEG3) and si-negative control (si-NC), levels of MEG3 and microRNA (miR)-149-3p were detected using reverse transcription-quantitative PCR, Proliferation and apoptosis were examined using the Cell Counting Kit-8 and flow cytometry assays, respectively. Enzyme-linked immunosorbent assay (ELISA) was performed to detect the expression of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Protein levels of B-cell lymphoma-2 (Bcl-2), cleaved-caspase-3, cleaved-caspase-9, phosphorylated (p)-p65, total (t)-p65, p-lkBα and t-lkBα were measured by western blotting. Luciferase assay was conducted to examine the relationship between MEG3 and miR-149-3p. LncRNA MEG3 was highly expressed, whereas miR-149-3p expression was downregulated in smokers with COPD peripheral blood samples, compared with non-smokers and smokers without COPD samples. Compared with untreated human bronchial epithelial (HBE) cells, MEG3 expression was increased in cigarette smoke extract (CSE)-treated HBE cells. Compared with CSE-treated HBE cells transfected with si-NC, MEG3 knockdown promoted cell proliferation and inhibited apoptosis in CSE-treated HBE cells transfected with si-MEG3, and it also decreased the levels of IL-6, TNF-α, Bcl-2 and increased cleaved-caspase-3 and cleaved-caspase-9 in CSE-treated HBE cells transfected with si-MEG3. The luciferase assay demonstrated that miR-149-3p has target sites for MEG3. MEG3 was demonstrated to regulate the NF-κB signaling pathway by sponging miR-149-3p in CSE-treated HBE cells. In conclusion, these findings suggested that MEG3 promoted proliferation and inhibited apoptosis by regulating the NF-κB signal pathway via miR-149-3p in CSE-treated HBE cells. These results provide an insight for further verification and understanding of the molecular basis of COPD.
慢性阻塞性肺疾病(COPD)已成为一项重大的公共卫生风险。长链非编码RNA(lncRNAs)已被确定为参与肺细胞增殖、凋亡和炎性细胞因子表达的重要因素。选取66名受试者(18名非吸烟者、24名无COPD的吸烟者和28名患有COPD的吸烟者)的外周血样本以及经或未经香烟烟雾提取物(CSE)处理的HBE135-E6E7细胞作为研究对象。本研究旨在探究lncRNA母系表达基因3(MEG3)在COPD中的潜在机制。分别用微小RNA(miR)-149-3p模拟物、miR阴性对照模拟物、miR-149-3p抑制剂、miR阴性对照抑制剂、靶向MEG3的小干扰(si)RNA(si-MEG3)和si阴性对照(si-NC)转染后,采用逆转录定量PCR检测MEG3和微小RNA(miR)-149-3p的水平,分别使用细胞计数试剂盒-8和流式细胞术检测增殖和凋亡情况。采用酶联免疫吸附测定(ELISA)检测白细胞介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)的表达。通过蛋白质印迹法检测B细胞淋巴瘤-2(Bcl-2)、裂解的半胱天冬酶-3、裂解的半胱天冬酶-9、磷酸化(p)-p65、总(t)-p65、p-IκBα和t-IκBα的蛋白质水平。进行荧光素酶测定以检测MEG3与miR-149-3p之间的关系。与非吸烟者和无COPD的吸烟者样本相比,lncRNA MEG3在患有COPD的吸烟者外周血样本中高表达,而miR-149-3p表达下调。与未处理的人支气管上皮(HBE)细胞相比,经香烟烟雾提取物(CSE)处理的HBE细胞中MEG3表达增加。与转染si-NC的CSE处理的HBE细胞相比,敲低MEG3可促进转染si-MEG3的CSE处理的HBE细胞增殖并抑制其凋亡,并且还降低了转染si-MEG3的CSE处理的HBE细胞中IL-6、TNF-α、Bcl-2的水平,并增加了裂解的半胱天冬酶-3和裂解的半胱天冬酶-9的水平。荧光素酶测定表明miR-149-3p具有MEG3的靶位点。在经CSE处理的HBE细胞中,MEG3被证明可通过海绵化miR-149-3p来调节NF-κB信号通路。总之,这些发现表明,在经CSE处理的HBE细胞中,MEG3通过miR-149-3p调节NF-κB信号通路促进增殖并抑制凋亡。这些结果为进一步验证和理解COPD的分子基础提供了思路。