嗜肺军团菌抑制小鼠巨噬细胞内体溶酶体融合的机制探讨  

Investigating the mechanism of Legionella pneumophila inhibiting endosome-lysosome fusion in mouse macrophages based on transcriptome sequencing

作　　者：陈民佳 曹秀琴[2] 贺瑞霞 陈海霞 杨志伟 Chen Min-Jia;Cao Xiu-Qin;He Rui-Xia;Chen Hai-Xia;Yang Zhi-Wei(Department of Pathogenic Biology and Medical Immunology,School of Basic Medicine,Ningxia Medical University,Yinchuan,Ningxia 750004,China;Key Laboratory of Fertility Preservation and Maintenance,Ministry of Education,Ningxia Medical University,Yinchuan,Ningxia 750004,China)

机构地区：[1]宁夏医科大学基础医学院病原生物学与医学免疫学系,宁夏银川750004 [2]宁夏医科大学生育力保持省部级共建教育部重点实验室,宁夏银川750004

出　　处：《解放军医学杂志》2025年第2期176-187,共12页Medical Journal of Chinese People's Liberation Army

基　　金：国家自然科学基金(82060362);宁夏自然科学基金(2023AAC03182)。

摘　　要：目的探究嗜肺军团菌感染抑制小鼠巨噬细胞内体溶酶体融合的相关致病机制。方法将12只C57BL/6J小鼠随机分为对照组与嗜肺军团菌感染组(n=6),麻醉后经鼻分别滴入相同体积的生理盐水或嗜肺军团菌液;连续3 d记录体重变化,取出整肺观察其伤情,HE和免疫组化染色观察小鼠肺组织病理特征;转录组测序分析肺组织中的差异表达基因(DEGs)和相关信号通路。提取小鼠骨髓巨噬细胞(BMDMs),与嗜肺军团菌共培养,采用免疫荧光染色鉴定感染情况,转录组测序分析感染前后的DEGs和富集的相关信号通路。筛选感染后共同参与信号通路的核心基因,用RT-qPCR验证核心基因mRNA表达水平在体内外的一致性,Western blotting检测相关蛋白的表达情况,细菌繁殖实验检测嗜肺军团菌在细胞内的繁殖情况。结果与对照组比较,感染后2 d、3 d,嗜肺军团菌感染组小鼠体重明显下降(P<0.001),左右肺组织水肿并呈红色肝样变,病变区域由肺门向肺周边蔓延;HE染色显示嗜肺军团菌感染组小鼠肺泡腔炎性细胞浸润增多、肺泡间隔增厚、纤维蛋白渗出增多;免疫组化检测结果显示,嗜肺军团菌感染组小鼠肺组织髓过氧化物酶(MPO)阳性面积百分比明显增高(P<0.001);转录组测序共筛选出DEGs 2550个,其中上调基因1444个,下调基因1106个;KEGG富集分析显示,富集通路主要涉及肿瘤坏死因子、类风湿关节炎、Rap1、PI3K-Ak和吞噬体通路等。免疫荧光检测结果显示,嗜肺军团菌在体外小鼠BMDMs内增殖;转录组测序筛选出DEGs 2550个,其中上调基因1677个,下调基因873个;KEGG富集分析显示,富集通路涉及癌症中的转录失调、PI3K-Akt和吞噬体通路等。筛选出富集在吞噬反应集群中的DEGs,得到小鼠肺组织和BMDMs重叠的微管蛋白β1(Tubb1)等13个核心基因。RT-qPCR检测结果显示,小鼠肺组织和BMDMs感染嗜肺军团菌后,Tubb1表达水平均明显降低(P<0.001);WeObjective To explore the pathogenic mechanisms of Legionella pneumophila(L.pneumophila)infection inhibiting the fusion of endosome-lysosome fusion in mouse macrophages.Methods Twelve C57 mice were randomly divided into control group and L.pneumophila infection group(n=6 each).After anesthesia,an equal volume of physiological saline or L.pneumophila solution was administered nasally.Body weight changes were monitored for 3 consecutive days,and the lungs were extracted to assess injury.Hematoxylin and eosin(HE)staining and immunohistochemical staining were performed to observe the pathological characteristics of lung tissue in both groups.Transcriptome sequencing was utilized to analyze differentially expressed genes(DEGs)and associated signaling pathways in lung tissues.Mouse bone marrow macrophages(BMDMs)were isolated and cocultured with L.pneumophila,with infection status confirmed by immunofluorescence staining.Transcriptome sequencing was employed to analyze DEGs and enriched related signaling pathways before and after infection.Core genes involved in the postinfection signaling pathway were identified,and the consistency of their mRNA expression levels in vivo and in vitro was verified using RT-qPCR.The expression of relevant proteins was detected by Western Blotting,and bacterial proliferation assays were conducted to evaluate the intracellular replication of L.pneumophila.Results Compared with control group,the body weight of mice in L.pneumophila infection group significantly decreased(P<0.001)on the second and third day post-infection.Edema and red hepatoid degeneration were observed in both left and right lung tissues,with lesion areas spreading from the hilum to the lung periphery.HE staining revealed increased inflammatory cell infiltration in the alveolar spaces,thickening of alveolar septa and increased fibrin exudation in L.pneumophila infection group.Immunohistochemistry results showed a significant increase in myeloperoxidase(MPO)activity in the lung tissue infected mice(P<0.001).Transcriptome seq

关 键 词：嗜肺军团菌 微管蛋白β1 内体溶酶体融合 转录组测序 巨噬细胞 

分 类 号：R378.99[医药卫生—病原生物学]