白细胞介素-17在慢性阻塞性肺疾病患者中的表达及作用机制

目的探讨白细胞介素-17(interleukin-17,IL-17)在慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)患者中的表达及作用机制。方法根据慢性阻塞性肺疾病患者的病情严重程度分为急性加重期组(AECOPD group)和稳定期组(COPD group),健康体检者作为对照组,各46例。酶联免疫吸附试验测定血清、肺泡灌洗液、呼出气冷凝液中的IL-17含量。香烟烟雾提取物(cigarette smoke extract,CSE)或IL-17处理A549,蛋白质免疫印迹、酶联免疫吸附试验、流式细胞术依次检测细胞中相关蛋白的表达、分泌与凋亡情况。结果 AECOPD组患者的血清、肺泡灌洗液和呼出气冷凝液中IL-17的含量均高于COPD组和对照组。CSE可促进肺泡上皮细胞表达IL-17RC,而且具有剂量依赖效应,使用PI3K/AKT信号通路抑制剂LY294002可部分降低IL-17RC的表达。IL-17A可促进肺泡上皮细胞分泌IL-8和TNF-α,可以诱导肺泡上皮细胞早期凋亡细胞和晚期凋亡细胞比例增加,与CSE共同作用时具有协同效应。IL-17A可促进促凋亡蛋白Bax的表达,抑制抗凋亡蛋白Bcl-xl和Bcl-2表达,可促进Caspase 3和Caspase 9蛋白活化,与CSE共同作用时具有协同效应。结论 IL-17在COPD患者中高表达,且急性加重期高于稳定期。CSE可通过PI3K/AKT信号通路诱导IL-17RC表达,CSE可与IL-17协同诱导肺泡上皮细胞分泌炎症因子和并通过线粒体依赖的途径诱导其凋亡。

The expression and role of IL-17 in patients with chronic obstructive pulmonary disease

This study was performed to investigate the expression and role of IL-17 in patients with chronic obstructive pulmonary disease(COPD). According to disease severity, the patients with COPD were divided into the acute exacerbation period group(AECOPD group) and the stable period group(COPD group), while healthy individuals were selected as controls. The levels of IL-17 in serum, bronchoalveolar lavage fluid and exhaled breath condensate were determined by enzyme-linked immunosorbent assay(ELISA). In vitro, alveolar epithelial cells were stimulated by cigarette smoke extracts(CSE) or IL-17A. Data showed that the expression of IL-17 in AECOPD group was higher than that in COPD group and control group;Western blotting showed that CSE could promote IL-17RC expression in dose-dependent manner, which could be partially prevented by LY294002(PI3K/AKT signaling pathway inhibitor). ELISA and flow cytometry showed that the secretion of inflammatory factors and the proportion of apoptotic cells were increased by IL17A and/or CSE. IL-17A and/or CSE could promote the expression levels of Bax, Caspase 3 and Caspase 9, while inhibit the expression of Bcl-xl and Bcl-2. In conclusion, IL-17 is highly expressed in COPD patients, especially in the acute exacerbation period. CSE can induce IL-17RC expression through PI3K/AKT signaling pathway, and synergize with IL-17 to induce inflammatory factors secretion in alveolar epithelial cells and induce apoptosis through mitochondrial dependent pathway.