Immunopathology of the Pneumocystis Life Cycle Stages

肺孢子虫生命周期阶段的免疫病理学

• 批准号: 8397516
• 负责人: Melanie T Cushion
• 金额: --
• 依托单位: CINCINNATI VA MEDICAL CENTER RESEARCH
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8397516
• 关键词: 3-Dimensional; Aging; Alveolar Macrophages; Anidulafungin; Animals; Binding; Biological Assay; CD8B1 gene; Cell Wall; Chronic Disease; Chronic Obstructive Airway Disease; Clinical; Comorbidity; Complication; Cyst; Development; Ensure; Equilibrium; Gene Expression; Glucans; Goals; Growth; HIV; Human; Immune; Immune response; Immune system; In Vitro; Infection; Infectious Agent; Inflammatory Response; Leukocytes; Life; Life Cycle Stages; Lung; Malignant neoplasm of lung; Mammals; Molecular; Molecular Profiling; Mus; Mycoses; Natural History; Opportunistic Infections; Organism; Partner in relationship; Pathogenesis; Patients; Persons; Phagocytosis; Phase; Pneumocystis; Pneumocystis Infections; Pneumocystis carinii Pneumonia; Pneumonia; Population; Rattus; Registries; Reproduction spores; Research Personnel; Risk; Role; Route; Series; Severity of illness; Silver Methenamine; Staging; Staining method; Stains; System; T-Lymphocyte; Thick; Travel; Veterans; asexual; beta-1,3-D-glucan; cytokine; effective therapy; fungus; immunopathology; immunosuppressed; in vivo; infected vector rodent; inhibitor/antagonist; insight; mortality; receptor; reconstitution; response; tool; transmission process

DESCRIPTION (provided by applicant): Fungal organisms in the genus Pneumocystis, were first clinically noticed because they caused an oftentimes lethal pneumonia (PCP) in humans and other mammals with compromised immune status. Today, the niche of these fungi have expanded to include patients with underlying chronic diseases like COPD, where their presence has been suggested to be a co-morbidity factor. Limited progress has been made in understanding the life cycle, transmission, and natural history of Pneumocystis, due in large part to the absence of a continuous in vitro culture system. The strategies used by these organisms to grow and survive in the context of an intact or immune-debilitated host are largely unknown. The actual agent of infection, the transmissive form, has not been identified, nor has its mode of travel, generally thought to be via an airborne spore. The life cycle of Pneumocystis involves trophic forms (trophs), thought to be the vegetative, asexually dividing life cycle stage; as well as several other developmental stages including the cyst form, which contains 8 ascospores. The cyst is distinct from the trophs in that it contains a thick cell wall comprised mostly of B-1,3 glucan; is larger (5-8um vs 1-4um); and stains with the fungal wall stain, methenamine silver. Cyst formation is thought to result from mating of trophs, but the interplay between the asexual and sexual phases is not clear. During the tenure of the previous Merit Review, we found that the treatment of Pneumocystis infections with echinocandins suppressed the formation of B-1,3-glucan thereby dramatically shifting the mixed cyst and troph populations in immunosuppressed mice and rats to one made almost exclusively of trophic forms. Strikingly, the mortality was markedly reduced in these mice, yet large populations of trophs were present in their lungs. Moreover, echinocandin treated mice were unable to transmit the infection. In the present proposal, we will use the echinocandins as molecular tools to dissect the life cycle in a manner that has never been available to investigators before. It is our central hypothesis that the asexual and sexual cycles act in concert to maintain a balance within the mammalian lung that permits a long and sustainable infection that ensures sustained transmission without demise of the host. We posit that cysts are the agents of transmission and the process of cyst formation requires B-1,3-glucan. However, the presence of cysts via B-1,3 glucan induces a detrimental inflammatory response in the host that increases severity of disease. In the present proposal, we will identify the immune responses evoked by each different population and dissect the life cycle of Pneumocystis using the echinocandins. Towards these goals, we propose the following specific aims: (1) Dissect the Pneumocystis life cycle using the echinocandin, anidulafungin, as a molecular tool by transcriptional analyses and in vivo studies to assess transmission and identify the infectious agent of Pneumocystis infection; (2) Characterize the P. murina cyst and trophic form interactions with alveolar macrophages through a series of binding and phagocytosis assays; and (3) Investigate the role of P. murina cysts in the deleterious pulmonary hyperinflammatory response following immune reconstitution by evaluating cytokine and cellular profiles in the lungs of cyst replete and cyst depleted populations of P. murina.

描述（由申请人提供）： 首先注意到肺炎属的真菌生物在临床上首先注意到，因为它们在人类和其他免疫状态受损的人类和其他哺乳动物中经常引起致命性肺炎（PCP）。如今，这些真菌的利基市场已经扩展到包括COPD等潜在慢性疾病的患者，在该患者中，他们的存在被认为是合并症。在理解肺类胸藻的生命周期，传播和自然史上，取得了有限的进展，这在很大程度上是由于缺乏连续的体外培养系统。这些生物在完整或免疫分配宿主的背景下生长和生存的策略在很大程度上是未知的。尚未确定感染的实际因素，即传播形式，也没有被认为是通过空中孢子的旅行方式。肺结压的生命周期涉及营养形式（Trophs），被认为是营养，无性划分的生命周期阶段。以及其他几个发育阶段，包括囊肿形式，其中包含8种子孢子。囊肿与Trophs不同，因为它包含一个厚的细胞壁，其中主要由B-1,3葡萄糖组成。更大（5-8UM vs 1-4UM）；并用真菌墙壁染色，甲胺银染色。囊肿的形成被认为是由于滋养的交配而导致的，但是无性阶段和性阶段之间的相互作用尚不清楚。 在先前的优异综述期间，我们发现用棘齿蛋白治疗肺类胸膜感染抑制了B-1,3-葡聚糖的形成，从而在免疫抑制的小鼠和大鼠中急剧转移了混合的囊肿和Troph群体，将其几乎独立地由营养性形成。令人惊讶的是，这些小鼠的死亡率显着降低，但肺中存在大量的滋养量。此外，经棘齿治疗的小鼠无法传播感染。在本提案中，我们将使用echinocandins作为分子工具，以以前从未对研究人员使用的方式剖析生命周期。 我们的核心假设是，无性周期和性周期共同行动，以保持哺乳动物肺部的平衡，从而允许长期且可持续的感染，可确保持续传播而不会消亡宿主。我们认为囊肿是传播的药物，囊肿形成过程需要B-1,3-葡聚糖。然而，通过B-1,3葡聚糖的囊肿的存在会引起宿主的有害炎症反应，从而增加了疾病的严重程度。在本提案中，我们将确定每个不同人群引起的免疫反应，并使用棘突素剖析肺炎囊肿的生命周期。达到这些目标，我们提出了以下特定目的：（1）通过转录分析和体内研究，使用棘齿素（Anidulafungin）作为一种分子工具来剖析肺母囊生命周期，以评估传播和识别肺细胞感染的传播剂； （2）通过一系列结合和吞噬作用测定法表征了Murina囊肿和营养形式与肺泡巨噬细胞的相互作用； （3）通过评估囊肿的囊肿伴有细胞因子和细胞谱的细胞因子和细胞谱，研究囊肿和囊肿菌群的肺中的细胞因子和细胞谱，研究了穆丽娜囊肿在有害肺高炎反应中的作用。