熏烟对肺组织AQP1表达与定位的影响

Effect of smoking on expression and localization of aquaporin1(AQP1)in lung tissue

目的探讨水通道蛋白1(Aquaporin1,AQP1)在慢性阻塞性肺病(Chronic obstruc-tive pulmonary disease,COPD)和熏烟诱导的COPD小鼠模型中的表达变化。方法选取SPF级昆明小鼠30只,4周龄,采用随机数字表法分为空白对照组、熏烟3个月组和熏烟6个月组,各10只。熏烟组小鼠构建熏烟诱导的COPD小鼠模型,空白对照组小鼠不进行任何处理。免疫组织化学法和蛋白印迹法分别测定各组小鼠肺组织中的AQP1蛋白表达量。体外使用尼古丁刺激人非小细胞肺癌细胞系A549,分为对照组(PBS)、3μmol/L尼古丁组(3μmol/L)和5μmol/L尼古丁组(5μmol/L),测定各组A549细胞中的AQP1蛋白表达量。用“limma”函数对COPD数据进行差异表达基因分析;对AQP1表达量与差异表达基因进行Pearson相关性分析;用GeneMANIA平台对相关性强的基因进行富集分析。结果免疫组织化学结果显示,对照组小鼠肺组织中AQP1主要分布于肺组织毛细血管内皮细胞和红细胞内,在Ⅱ型肺泡上皮细胞的顶膜也有少量分布。HE染色结果显示,对照组小鼠肺泡及肺间质无炎症细胞浸润,呼吸道通畅;熏烟3个月组小鼠肺组织可见肺大泡形成,小气道及血管周围可见炎性细胞浸润,并伴有黏性分泌物堆积;熏烟6个月组小鼠肺组织可见大量肺大泡,血管周围有大量炎性细胞聚集。蛋白印迹法检测结果显示,熏烟3个月组和6个月组小鼠肺组织中AQP1蛋白表达量较对照组分别减少约40%和60%(P<0.01)。体外使用尼古丁刺激结果显示,与对照组比较,3μmol/L尼古丁组AQP1蛋白表达量升高(P<0.05);5μmol/L尼古丁组AQP1蛋白表达量更高(P<0.01)。生物信息学分析结果显示,数据集GSE103174中,与正常肺组织比较,COPD患者肺组织中AQP1显著降低(P=0.00013);差异表达基因分析发现,与正常组比较,COPD患者有62个基因表达上调和56个基因表达下调;Pearson相关性分析发现,表皮调节素(EREG)、前列腺素G/H合酶2(PTGS2)、双调蛋白(AR-EG)等基因与AQP1相关性系数(R2)>0.5;富集分析结果显示,EREG、白介素-6(IL-6)、AREG参与上皮细胞增殖过程,细胞色素P450家族1亚家族B成员1(CYP1B1)、白介素-1β(IL-1β)、IL-6、PTGS2参与血管内皮生长因子的产生。结论COPD患者与熏烟诱导COPD小鼠模型的肺组织AQP1蛋白表达降低,这可能与尼古丁刺激肺泡上皮细胞导致AQP1增高无关。

Objective To investigate the expression changes of aquaporin 1(AQP1)in chronic obstructive pulmonary disease(COPD)and smoking-induced mouse models.Methods 30 SPF grade Kunming mice,4 weeks of age,were selected and divided into control group,3-month smoking group and 6-month smoking group with 10 mice each.COPD mice model was induced by smoking,and control mice did not undergo any treatment.AQP1 protein expression was measured in lung tissues of each group by immuno-histochemistry and Western blot.In vivo use of nicotine to stimulate the human non-small cell lung cancer cell line A549,which were divided into control(PBS),3μmol/L nicotine(3μmol/L)and 5μmol/L nico-tine(5μmol/L),for AQP1 protein expression in A549 cells in each group.Differential expressed gene analysis of COPD transcriptome data with“limma”function;Pearson correlation analysis between AQP1 expression and differentially expressed genes;and enrichment analysis of highly correlated genes using the GeneMANIA platform.Results Immunohistochemical results showed that AQP1 in the lung tissue of the control mice was mainly distributed in the capillary endothelial cells and red blood cells of the lung tissue,and it also slightly distributed in the apical membrane of the typeⅡalveolar epithelial cells.HE staining results showed that the control mice had no inflammatory cells in alveoli and interstitium and smooth re-spiratory tract.The lung tissue of mice in the 3-month smoking group showed the formation of pulmonary alveoli,inflammatory cell infiltration around small airways and blood vessels,and accumulation of viscous secretions;A large number of pulmonary alveoli were observed in the lung tissue of mice in the 6-month smoking group,and there were numerous inflammatory cell clusters around the blood vessels.The west-ern blot showed that AQP1 protein expression was reduced by 40%and 60%compared with the control group(P<0.01).In vitro nicotine stimulation showed that AQP1 protein expression was increased in 3μmol/L nicotine(P<0.05);AQP1 protein expression was more increased in 5μmol/L nicotine(P<0.01).Bioinformatics analysis showed that in dataset GSE103174,AQP1 was significantly decreased in COPD lung tissue compared with normal lung tissue(P=0.00013).Analysis of the differentially ex-pressed genes found that,compared with the normal group,COPD patients had 62 genes up-regulated and 56 genes down-regulated;Pearson correlation analysis found that,the correlation coefficient between Epi-regulin(EREG),prostaglandin G/H synthase 2(PTGS 2),amphiregulin(AREG)and AQP1(R2)was>0.5;The results of the enrichment analysis showed that,EREG,interleukin-6(IL-6),and AREG were involved in the process of epithelial cell proliferation,Cytochrome P450 family 1 subfamily B member 1(CYP1B1),interleukin-1β(IL-1β),IL-6 and PTGS 2 were involved in the production of vascular endotheli-al growth factor.Conclusion The expression of AQP1 protein in lung tissue of COPD patients and smok-ing induced COPD mice model were decreased,which may not be related to the increase of AQP1 caused by nicotine stimulation of alveolar epithelial cells.