Mycoplasma pneumoniae activation of airway epithelium

描述（由申请方提供）：肺炎支原体是人类肺部疾病的主要原因，与气道上皮细胞的初始相互作用可能有助于随后的疾病发展。很明显，针对支原体的免疫应答是疾病的主要组成部分，在呼吸道粘膜下层中招募和发展免疫介导的炎症应答。因此，由气道上皮细胞产生的因子可能影响这些免疫介导的病变的发病机制;然而，由气道上皮细胞产生的细胞因子/趋化因子的完整补充是未知的。此外，参与这些细胞活化的机制和支原体组分尚未表征。如果了解这些信息，可以促进干预支原体和其他肺部疾病的新方法的开发。本项目的长期目标是确定支原体呼吸道疾病中产生免疫反应的分子机制。本项目拟检验M.肺炎链球菌刺激人呼吸道支气管上皮细胞产生趋化因子或其他可能导致炎性病变的细胞因子。此外，我们提出支原体粘附蛋白促进支原体脂蛋白和呼吸道上皮细胞的Toll样受体（TLR）之间的相互作用，这反过来又刺激上皮细胞产生这些因子。具体而言，我们提出解决以下问题：1）做M。肺炎支原体膜成分激活或损伤人支气管上皮细胞，这是否依赖于粘附分子？2)M. pneumoniae通过Toll样受体（TLR）刺激人支气管上皮细胞？实验设计为：1）活支原体、支原体膜和脂蛋白将刺激人支气管上皮细胞系。将测定细胞因子/趋化因子mRNA和蛋白水平。我们将比较粘附亲本支原体菌株与非粘附菌株的活性。2)在支原体刺激前后监测支气管上皮细胞的TLR表达。将用表达每种人TLR的质粒转染缺乏TLR的细胞系，以确定其在支原体（细胞、膜和脂蛋白）刺激细胞中的作用。TLR对人支气管上皮细胞的作用将使用阻断抗体或用TLR的无活性形式转染来确定。这些研究将为未来的研究提供基础，以进一步阐明这些反应所涉及的分子事件，并检查上皮来源的趋化因子/细胞因子在疾病发病机制中的作用。此外，这些事件可能会导致哮喘和其他呼吸道疾病的加重。因此，这些事件中的每一个的调节可能导致针对支原体和其他慢性呼吸道疾病的新疗法。这种细菌，肺炎支原体，是导致“行走性肺炎”的原因，在美国至少有30%的肺炎病例与严重的哮喘有关。这项拟议中的研究将研究这种细菌导致肺部疾病和更严重哮喘的机制。最终，我们希望这些研究将通过促进患者肺部的有利反应而不是有害反应来更有效地治疗这种细菌引起的疾病。

DESCRIPTION (provided by applicant): Mycoplasma pneumoniae is a major cause of lung disease in humans, and the initial interaction with airway epithelial cells is likely to contribute to subsequent disease development. It is clear that immune responses against mycoplasma are a major component of disease with the recruitment and development of immune-mediated inflammatory responses in the submucosa of the respiratory tract. Thus, the factors produced by airway epithelial cells are likely to influence the pathogenesis of these immune-mediated lesions; however, the full complement of cytokines/chemokines produced by airway epithelial cells is unknown. Furthermore, the mechanisms and mycoplasma components involved in the activation of these cells is uncharacterized. If understood, this information could facilitate the development of new approaches to intervene in mycoplasma and other pulmonary diseases. The long-term objective of this project is to determine the molecular mechanisms central to the generation of immune responses in mycoplasma respiratory disease. This project proposes to test the hypothesis that M. pneumoniae stimulate human respiratory bronchoepithelial cells to produce chemokines or other cytokines that are likely to contribute to the inflammatory lesions. Furthermore, we propose that mycoplasma adhesion protein promote the interaction between mycoplasma lipoproteins and toll-like receptors (TLR) of respiratory epithelial cells, which in turn stimulate the production these factors by epithelial cells. Specifically, we proposed to address the following questions: 1) Do M. pneumoniae membrane components activate or damage human bronchoepithelial cells and is this dependent on adhesion molecules? 2) Does M. pneumoniae stimulate human bronchoepithelial cells via toll-like receptors (TLR)? The experimental designs are: 1) Viable mycoplasma, mycoplasma membranes and lipoproteins will stimulate a human bronchoepithelial cell line. Cytokine/chemokine mRNA and protein levels will be determined. We will compare the activity of an adherent parental mycoplasma strain with a nonadherent strain. 2) The expression of TLR by bronchoepithelial cells will be monitored before and after mycoplasma stimulation. Cell lines lacking TLR will be transfected with plasmids expressing each of the human TLR to determine their roles in mycoplasma (cell, membranes and lipoproteins) stimulation of cells. The role of the TLR on human bronchoepithelial cells will be determined using blocking antibodies or transfection with inactive forms of TLR. These studies will provide the foundation for future studies to further elucidate the molecular events involved in these responses, and examine the role of epithelium-derived chemokines/cytokines in disease pathogenesis. Furthermore, it is likely that these events contribute to the exacerbation of asthma and other respiratory diseases. Thus, modulation of each of these events may lead to novel therapies against mycoplasma and other chronic respiratory diseases. The bacterium, Mycoplasma pneumoniae, is responsible for "walking pneumonia" which comprises at least 30% of the pneumonia cases in the United States and associated with severe asthma. The proposed research will study the mechanism through which this bacterium causes lung disease and more severe asthma. Ultimately, we expect these studies will lead to more effective treatments of diseases due to this bacterium by means of promoting favorable, rather than harmful, responses within the lungs of patients.