Surfactant Proteins and the Host Response to Mycoplasma

表面活性蛋白和宿主对支原体的反应

• 批准号: 6853456
• 负责人: DENNIS R. VOELKER
• 金额: $ 24.82万
• 依托单位: NATIONAL JEWISH HEALTH
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2009-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6853456
• 关键词: Mycoplasma pneumoniae; asthma; bacteria infection mechanism; bacterial proteins; host organism interaction; human tissue; inflammation; interferon gamma; interleukin 8; laboratory mouse; laboratory rat; ligands; liquid chromatography mass spectrometry; macrophage; mycoplasmal pneumonia; nitric oxide; pulmonary surfactants; respiratory epithelium; tumor necrosis factor alpha

Mycoplasma pneumoniae can exacerbate asthma and recent clinical evidence links the presence of the organism with chronic asthma. The focus of this proposal is to examine the interactions between M. pneumoniae and the pulmonary surfactant proteins, SP-A and SP-D. Preliminary evidence demonstrates that SP-A and SP-D bind to the bacteria with high affinity and that the principal ligands are membrane lipids. We plan to examine the basis of the physical interaction between mycoplasma, SP-A and SP-D by elucidating the structures of the lipid ligands. These studies will also utilize a large collection of SP-A and SP-D structural variants to identify the protein domains that are required for interaction with specific lipid ligands. The interaction of SP-A with mycoplasma markedly attenuates the growth of the bacteria and we will also define which protein domains are essential for this process. SP-A amplifies the host response to mycoplasma by stimulating the production of TNFalpha and nitric oxide from macrophages several fold. The SP-A mutant proteins will also be used to identify the domains of the protein that are required for this amplification of the inflammatory response. Both alveolar and bronchial epithelial cells are exposed to mycoplasma during infection. We will determine the cytokine response of these epithelia to mycoplasma and elucidate how this response is modulated by SP-A and SP-D. In conjunction with the proposed in vitro studies we plan to examine the in vivo response of mice challenged with mycoplasma and the modulation of this response by SP-A and SP-D. Both normal and SP-A null mice will be challenged with the bacteria and its derivative components under conditions of supplementation with exogenous SP-A and SP-D. From the experiments described in this proposal we will identify specific lipid and protein components of M. pneumoniae that interact with the surfactant proteins and regulate the host inflammatory response. This information will provide important new details about the events that follow mycoplasma infection and how they can contribute to asthma.

肺炎支原体会加剧哮喘，最近的临床证据表明该微生物的存在与慢性哮喘有关。该提案的重点是检查肺炎支原体与肺表面活性蛋白 SP-A 和 SP-D 之间的相互作用。初步证据表明，SP-A 和 SP-D 以高亲和力与细菌结合，主要配体是膜脂。我们计划通过阐明脂质配体的结构来研究支原体、SP-A 和 SP-D 之间物理相互作用的基础。这些研究还将利用大量 SP-A 和 SP-D 结构变体来鉴定与特定脂质配体相互作用所需的蛋白质结构域。 SP-A 与支原体的相互作用显着减弱细菌的生长，我们还将定义 哪些蛋白质结构域对此过程至关重要。 SP-A 通过数倍刺激巨噬细胞产生 TNFα 和一氧化氮，从而放大宿主对支原体的反应。 SP-A 突变蛋白还将用于识别炎症反应放大所需的蛋白结构域。感染期间肺泡和支气管上皮细胞均暴露于支原体。我们将确定这些上皮细胞对支原体的细胞因子反应，并阐明 SP-A 和 SP-D 如何调节这种反应。结合拟议的体外研究，我们计划检查支原体攻击小鼠的体内反应以及通过以下方式调节这种反应： SP-A 和 SP-D。在补充外源性 SP-A 和 SP-D 的条件下，正常小鼠和 SP-A 缺失小鼠都会受到细菌及其衍生成分的攻击。从本提案中描述的实验中，我们将鉴定肺炎支原体的特定脂质和蛋白质成分，这些成分与表面活性剂蛋白相互作用并调节宿主炎症反应。这些信息将提供有关支原体感染后发生的事件以及它们如何导致哮喘的重要新细节。