Pneumocystis carinii: Macrophage & Epithelial Activation

卡氏肺孢子虫：巨噬细胞

• 批准号: 8711534
• 负责人: ANDREW H LIMPER
• 金额: $ 38.96万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-07-10 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8711534
• 关键词: Acquired Immunodeficiency Syndrome; Address; Adhesions; Adrenal Cortex Hormones; Alveolar Macrophages; Animals; Anti-Inflammatory Agents; Anti-inflammatory; Antibiotics; Blood specimen; Cell Wall; Cell membrane; Cells; Cessation of life; Correlative Study; Cyst; Data; Development; Disease; Environment; Enzymes; Epithelial; Epithelial Cells; Fibronectins; Funding; Gases; Generations; Genes; Glucans; Glucose; Glycosphingolipids; Health; Host Defense; Human; ITGAM gene; ITGB2 gene; Immune response; Immunosuppression; Immunosuppressive Agents; Infection; Inflammation; Inflammatory; Inflammatory Response; Injury; Lactosylceramides; Life Cycle Stages; Ligase; Light; Link; Lung; Lung Inflammation; MAP Kinase Gene; Measures; Mediating; Membrane; Modeling; Morbidity - disease rate; Mus; New Agents; Organism; Outcome; Pathway interactions; Patients; Pneumocystis; Pneumocystis Infections; Pneumocystis carinii; Pneumocystis carinii Pneumonia; Pneumonia; Prophylactic treatment; Proteins; Rattus; Receptor Signaling; Reducing Agents; Regimen; Regulation; Relative (related person); Reporting; Rodent; Role; Saccharomyces cerevisiae; Sampling; Side; Signal Pathway; Signal Transduction; Stimulus; System; TNF gene; Testing; Therapeutic; Vertebral column; Work; activating transcription factor; base; cell type; chemokine; cytokine; dectin 1; effective therapy; fungus; glucan synthase; host organism interaction; immunosuppressed; improved; inhibitor/antagonist; lung injury; macrophage; mortality; novel; prophylactic; public health relevance; receptor; response

DESCRIPTION (provided by applicant): Pneumocystis jirovecii pneumonia remains a major cause of infection in patients with AIDS. Lung inflammation during Pneumocystis pneumonia (PcP) strongly contributes to lung injury and death. Anti- inflammatory corticosteroids (in addition to antibiotics) significantly improve outcome during PcP, but are associated with further immune suppression and co-infection. Numerous studies demonstrate that Pneumocystis (Pc) cell wall components including ?-glucans interact with alveolar macrophages and epithelial cells to stimulate the release of cytokines and chemokines that promote inflammatory cell recruitment into the lungs. ?-glucans are homopolymers of D-glucose consisting of ?-1,3 linked chains with variable amounts and configurations of ?-1,6 linked glucose side chains. Most studies have focused on unfractionated cell wall ?- glucans or on ?-1,3 glucans during inflammatory responses to fungi. However, recent studies strongly indicate that actually the ?-1,6 glucan exposed side chains of fungal cell walls are responsible for a considerable amount, if not the major portion, of host inflammatory responses. To date, the role of ?-1,6 glucans have not been studied in any pathogenic fungi such as Pneumocystis, only in S. cerevisiae models. To address ?-1,6 glucans in Pc, over the last funding period we demonstrated that P. carinii cell walls indeed contain significant ?-1,6 glucans, in addition to the ?-1,3 glucan generated by PcGsc1 in Pc. We further have shown that ?-1,6 glucans strongly stimulate inflammatory signaling in lung cells, and have identified the ?-1,6 glucan generating machinery in Pneumocystis mediated by the PcKre6 enzyme. We also observed that host cell membrane lactosylceramide strongly participates in inflammatory activation in response to Pc ? -1,6 glucans. Despite this progress, considerable gaps still exist in our understanding of these important host-organism interactions. In particular, the regulation of Pc ? -1,6 (as opposed to ? -1,3) glucan in the organism is not well understood. It is also unknown how Pc cell wall generation responds to the lung micro-environment. In addition, host receptors and signaling pathways that specifically mediate inflammatory signaling to Pc ? -1,6 compared to ? -1,3 glucans are not yet defined. Finally, strategies to ameliorate the associated exuberant and damaging lung inflammation during Pneumocystis infection are not well developed. On this basis, we hypothesize that Pneumocystis ? -1,6 glucans strongly activate deleterious inflammatory signaling in epithelial cells and macrophages through lactosylceramide mediated MAPK signaling with subsequent cytokine/chemokine generation. These concepts will be addressed through three independent, but closely interrelated, aims. In Aim 1, we will evaluate the P. carinii ? -1,6 glucan synthetic machinery (compared to the ?-1,3) by characterizing the PcKre6 and PcGsc1 synthetases, their regulation over the life cycle of Pc, and their responses to environmental stimuli including interactions with host epithelial cells. We will further quantify the relative content of ?-1,6 as opposed to ?-1,3 glucans both in P. carinii and P. jirovecii samples, and will study the regional localization of ?-1,6 and ?-1,3 glucans in the Pc cyst wall. Under Aim 2, we will evaluate mechanisms by which whole Pneumocystis and isolated Pc ?-1,6 vs. ?-1,3 glucans separately activate MAPK signaling in macrophages and epithelial cells, resulting in translocation of NF-?B, and release of inflammatory cytokines (TNF?) and chemokines (MIP- 2). We will also elaborate the role of membrane glycosphingolipids in mediating cellular activation, as well as defining the roles of the known general glucan receptors in triggering these specific interactions. We will further measure host humoral responses to Pc ?-1,6 and ?-1,3 glucans both in the immunosuppressed rat models, as well as in archival human BAL and blood samples. Finally, in Aim 3, we will evaluate the utility of glycospingolipid inhibitors and newly identified ?-1,6 gluca synthase inhibitors as prophylactic and therapeutic regimens for PcP, defining their impact on lung inflammation, gas exchange, and Pc burden. Better understanding the roles of ?-1,6 and ?-1,3 glucan related innate inflammatory signaling during PcP will better define mechanisms of lung injury during infection. Moreover, this proposal also presents the potential to develop new agents with strongly beneficial effects on organism-driven lung inflammation during this important cause of morbidity and mortality in patients with AIDS.

描述（由申请人提供）：肺炎肺炎肺炎肺炎仍然是艾滋病患者感染的主要原因。肺炎肺炎肺炎（PCP）期间的肺部炎症强烈导致肺损伤和死亡。抗炎性皮质类固醇（除抗生素外）在PCP期间显着改善预后，但与进一步的免疫抑制和共感染有关。大量研究表明，包括？ - 葡聚糖在内的肺炎（PC）细胞壁成分与肺泡巨噬细胞和上皮细胞相互作用，以刺激细胞因子和趋化因子的释放，从而促进炎症细胞募集到肺部。 ？ - 葡萄糖是由d-葡萄糖的均聚物组成的，由？-1,3链接链的链链，其量变量和构型为？-1,6链接的葡萄糖侧链。大多数研究都集中在未分流的细胞壁上？ - 葡萄糖或对真菌的炎症反应期间？-1,3葡萄糖。但是，最近的研究强烈表明，真菌细胞壁的glucan暴露侧链实际上是宿主炎症反应的相当数量（即使不是主要部分）。迄今为止，仅在酿酒酵母模型中，尚未在任何致病性真菌（例如肺炎藻）中研究？-1,6葡萄糖的作用。为了解决PC中的-1,6葡萄糖，在最后一个资金期间，我们证明了Carinii细胞壁确实包含明显的？-1,6葡萄糖，除了PC中PCGSC1产生的？-1,3葡萄糖。我们进一步表明，-1,6葡萄糖强烈刺激肺细胞中的炎症信号传导，并鉴定出由PCKRE6酶介导的肺炎藻中的？-1,6葡萄糖产生机械。我们还观察到宿主细胞膜乳糖基酰胺强烈参与响应PC的炎症激活？ -1,6葡萄糖。尽管取得了这种进步，但我们对这些重要的宿主和生物相互作用的理解仍然存在相当大的差距。特别是PC的调节？ -1,6（与？-1,3）在生物体中的葡聚糖尚不清楚。 PC细胞壁产生如何对肺微环境做出反应也未知。此外，宿主受体和信号通路专门介导PC的炎症信号传导？ -1,6与？ -1,3葡萄糖尚未定义。最后，改善肺炎囊体感染期间相关的旺盛肺部炎症和破坏性肺部炎症的策略尚未得到很好的发展。在此基础上，我们假设肺炎囊肿？ -1,6葡萄糖通过乳糖基酰胺介导的MAPK信号传导，强烈激活上皮细胞和巨噬细胞中有害的炎症信号传导，随后的细胞因子/趋化因子产生。这些概念将通过三个独立但紧密相关的目的来解决。在AIM 1中，我们将评估Carinii？ -1,6葡聚糖合成机械（与？-1,3相比）通过表征PCKRE6和PCGSC1合成酶，它们对PC生命周期的调节以及它们对环境刺激的反应，包括与宿主上皮细胞的相互作用。我们将进一步量化？-1,6的相对含量，与P. carinii和P. jirovecii样品中的？-1,3葡萄糖相反，将研究PC囊肿壁中的区域定位？-1,6和？-1,3葡萄糖。在AIM 2下，我们将评估整个肺炎和孤立的PC的机制？-1,6与？-1,3葡聚糖分别激活巨噬细胞和上皮细胞中的MAPK信号传导，从而导致NF-？b的转运，从而释放炎症细胞因子（TNF？）和趋化因子（TNF？）和趋化因子（TNF？）和趋化因子（MIP-2））。我们还将阐述膜糖磷脂脂在介导细胞活化中的作用，并确定已知的一般葡萄糖受体在触发这些特定相互作用中的作用。 我们将进一步衡量对PC的宿主体液反应？-1,6和？-1,3葡萄糖在免疫抑制的大鼠模型以及档案中的人类BAL和血液样本中。最后，在AIM 3中，我们将评估糖脂糖抑制剂和新鉴定的糖脂糖抑制剂的实用性？-1,6 gluca合酶抑制剂作为PCP的预防性和治疗方案，定义了它们对肺部炎症，气体交换和PC负担的影响。更好地理解？-1,6和？-1,3葡聚糖在PCP期间与葡聚糖相关的炎症信号的作用将更好地定义感染过程中肺损伤的机制。此外，该提案还提出了开发新药物对有机体驱动的肺部炎症具有强烈有益作用的新药物的潜力，在这一重要的艾滋病患者发病和死亡率的重要原因期间。