肺炎支原体膜脂蛋白诱导mICAM-1表达上调的机制的初步研究

发布时间：2018-06-08 06:00

本文选题：肺炎支原体 + 膜脂蛋白　；参考：《武汉大学》2005年硕士论文

【摘要】：肺炎支原体(Mycoplasma Pneumoniae,Mp)作为一种人源致病性支原体,其感染除了引起原发型非典性肺炎、咽炎、气管炎、支气管炎等呼吸道疾病以外,还可引起全身各系统的合并症。近年来,随着Mp感染引起全身多脏器的炎性损伤在国内外临床报道的增加,人们对其引起机体炎性损伤的分子免疫机制展开了多方面的研究。研究表明,人体单核吞噬细胞主要通过TLR2识别支原体膜脂蛋白成分并由NF-kB途径介导IL-1β、TNF-α、IL-12等促炎性细胞因子的释放;而上述前炎性细胞因子可增强mlCAM-1(CD54)在病灶中相关细胞上表达水平,加重机体的局部炎性反应。为了探讨肺炎支原体感染过程中,其膜脂蛋白成分能否通过TLR2诱导呼吸道局部病灶中单核/巨噬细胞和肺上皮细胞mlCAM-1表达水平的上调,为进一步阐明肺炎支原体感染所致肺部炎性反应机制奠定基础,本文以肺腺上皮细胞系A549细胞和髓样单核细胞系THP-1细胞作为靶细胞,用流式细胞术和荧光显微镜检测Mp-LAMP刺激组、抗人TLR2功能纯化抗体(TL2.1)阻断组及消化酶处理组的THP-1细胞mlCAM-1和TLR2的表达水平;用流式细胞术检测Mp-LAMP不同浓度刺激组、不同时间刺激组及消化酶处理组的A549细胞mlCAM-1和TLR2的表达水平以及具有生物学活性的肺炎支原体刺激后A549细胞胞内TLR2的表达水平。结果表明:与对照组相比,不同刺激浓度的Mp-LAMP对THP-1细胞膜上TLR2及mlCAM-1的表达均有明显的上调作用(P0.05),且表达水平的增加对Mp-LAMP的刺激具有浓度依耐性;用TL2.1将THP-1细胞膜上的TLR2阻断后,Mp-LAMP对mlCAM-1表达的诱导作用明显受到抑制(P0.01),其阻断效果随TL2.1量的增加而加强;相关分析表明mlCAM-1在THP-1细胞上的表达水平与TLR2密切相关(r=0.989,P0.01);经Mp-LAMP作用后,A549细胞膜上TLR2无任何表达,但mlCAM-1的表达水平明显上调(P0.01),且对Mp-LAMP具有浓度依耐性。随着Mp-LAMP作用时间的延长,A549细胞mlCAM-1表达水平逐渐上升,作用16h时达到高峰,然后开始下降。酶消化试验证实Mp-LAMP诱导
[Abstract]:Mycoplasma pneumoniae MP) as a human pathogenic mycoplasma, its infection not only causes primary SARS pneumonia, pharyngitis, bronchitis, bronchitis and other respiratory diseases, but also can cause systemic complications. In recent years, with the increase of the clinical reports of systemic multiple organ injury caused by MP infection, many studies have been carried out on the molecular immune mechanism of the systemic inflammatory injury caused by MP infection. Human mononuclear phagocytes recognize mycoplasma membrane lipoprotein by TLR2 and mediate the release of pro-inflammatory cytokines such as IL-1 尾 TNF- 伪 and IL-12 by NF-kB pathway, and these proinflammatory cytokines can enhance the expression level of mlCAM-1 / CD54) in the relevant cells. Aggravation of the body's local inflammatory response. In order to investigate whether the membrane lipoprotein of mycoplasma pneumoniae infection can induce the upregulation of the expression of mlCAM-1 in the local focus of respiratory tract by TLR2, the expression of mlCAM-1 in the pulmonary epithelial cells and mononuclear cells is up-regulated. In order to further elucidate the mechanism of pulmonary inflammatory response induced by mycoplasma pneumoniae infection, lung adenoepithelial cell line A549 and myeloid monocyte cell line THP-1 were used as target cells. Mp-LAMP stimulation group was detected by flow cytometry and fluorescence microscopy. The expression levels of mlCAM-1 and TLR2 in THP-1 cells were detected by flow cytometry. The expression levels of mlCAM-1 and TLR2 in A549 cells stimulated by different time groups and digested by digestive enzymes, and the expression levels of TLR2 in A549 cells stimulated by Mycoplasma pneumoniae. The results showed that the expression of TLR2 and mlCAM-1 on THP-1 cell membrane was significantly up-regulated by Mp-LAMP at different concentrations compared with the control group, and the increase of Mp-LAMP expression had a concentration-dependent tolerance to Mp-LAMP. The effect of Mp-LAMP on the expression of mlCAM-1 was significantly inhibited after TL2.1 was blocked by TLR2 on THP-1 cell membrane, and the blocking effect was enhanced with the increase of TL2.1. Correlation analysis showed that the expression level of mlCAM-1 in THP-1 cells was closely related to TLR2 0.989P0.01G, but no expression of TLR2 was found in A549 cells treated with Mp-LAMP, but the expression level of mlCAM-1 was significantly up-regulated in THP-1 cells and had concentration-dependent tolerance to Mp-LAMP. With the prolongation of Mp-LAMP, the expression of mlCAM-1 in A549 cells increased gradually, reached its peak at 16 h, and then began to decrease. Enzyme digestion test confirmed Mp-LAMP induction
【学位授予单位】：武汉大学
【学位级别】：硕士
【学位授予年份】：2005
【分类号】：R375

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