The role of sex in the life cycle of Pneumocystis

性在肺孢子虫生命周期中的作用

• 批准号: 10047702
• 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: 2018
• 资助国家: 美国
• 起止时间: 2018-10-01 至 2022-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10047702
• 关键词: 3-Dimensional; Address; Aftercare; Anidulafungin; Arthritis; Aspergillus; Biological; Bone Marrow; Candida albicans; Caring; Caspofungin; Cell Cycle; Cell Wall; Cells; Chronic; Chronic Obstructive Airway Disease; Clinical; Data; Environment; Exposure to; Female; Gene Expression; Gene Expression Profile; Gene Expression Profiling; Genes; Goals; HIV; Human; Immune; Immunocompromised Host; Immunosuppression; Immunotherapy; Infection; Infection prevention; Knowledge; Length; Life Cycle Stages; Link; Lung; Malignant Neoplasms; Metabolic; Methods; Microscopic; Modeling; Mus; Partner in relationship; Patients; Pharmaceutical Preparations; Phase; Phenotype; Pneumocystis; Pneumocystis Infections; Pneumocystis carinii; Pneumonia; Population; Proliferating; Property; Reporting; Rheumatoid Arthritis; Role; Sexual Reproduction; Signal Transduction; Stress; Time; United States; Up-Regulation; Veterans; Withdrawal; Withholding Treatment; asexual; base; cancer diagnosis; chronic inflammatory disease; clinically relevant; coping mechanism; fungus; genetic signature; high risk; immunological status; immunosuppressed; infected vector rodent; male; military veteran; novel therapeutics; pathogenic fungus; polyglucosan; prevent; prophylactic; sex; sexual debut; targeted treatment; therapy duration; transcriptome; transcriptome sequencing; transmission process; treatment duration; tumor necrosis factor-alpha inhibitor

Pneumocystis spp. are obligate fungal pathogens that cause a fatal pneumonia (PCP) in immunocompromised hosts. Few drugs are effective against PCP and there have been no new therapies for its treatment in decades. Typically, PCP has been associated with patients infected with HIV, however, the fulminate pneumonia, PCP, and colonization with Pneumocystis jirovecii (the species infecting humans) are emerging clinical problems in newly susceptible populations in the general and veterans’ populations including bone marrow recipients; patients receiving chronic immunotherapy for rheumatoid arthritis and other chronic inflammatory diseases; and cancer chemo- and immunotherapies. The life cycle of Pneumocystis is suggested to contain both an asexual replication cycle and a sexual cycle involving mating with subsequent formation of asci containing 8 ascospores (1). During the previous Merit Review, we showed that echinocandin treatment of rodents infected with P. murina and P. carinii, which target β-1,3-D-glucan synthesis (BG), depleted the asci which contain BG but large numbers of non-BG expressing life cycle stages remained in the lungs and were unable to proliferate. We further demonstrated that anidulafungin and caspofungin could prevent infection in a prophylactic model, suggesting that formation of asci via the sexual cycle may be required for a productive infection (2). Analysis of gene expression profiles of P. murina in mice treated with anidulafungin, showed strong upregulation of genes associated with sexual replication, though the resulting infections were devoid of asci, the product of sexual reproduction, suggesting that P. murina attempted to undergo sexual replication, but could not due to a lack of BG. Based on these data, we posit that asci, and thus sexual replication, is required to facilitate progression through the life cycle leading to a productive infection. We further posit that presence of asci is required for transmission of Pneumocystis infection. In the present proposal, we will explore 2 critical, but unanswered questions that will lead to a deeper knowledge of the life cycle of Pneumocystis, and also suggest potential vulnerabilities for targeted treatment concomitant with anidulafungin therapy: (1) Is sexual replication required for completion of the life cycle of Pneumocystis? Tracking of the replication status of P. murina during prolonged treatment with anidulafungin by global gene analysis, BG content, and microscopic methods will reveal whether the non-BG expressing forms numbers remain: 1) static over time, 2) increase, or 3) decrease; suggesting: 1) the lack of BG blocks replication; 2) that an asexual or alternative replication phase permits survival of the fungi; or 3) the lack of sexual replication results in elimination of the infection. (2) Can sexual replication rebound after cessation of prolonged anidulafungin treatment? Mice will be treated with anidulafungin for up to 8 weeks, with 2 cessation time points. Mice in the cessation groups will be tracked for microscopic, BG content, and gene expression evidence of asci formation and return of the pneumonia while remaining under immunosuppression. Mice in the treated and cessation groups will be evaluated for their ability to transmit the infection and the critical number of asci needed for transmission. All studies will be conducted in male and female mice, recognizing sex as a biological variable. The echinocandins are clinically available in the United States. Current monotherapy with any echinocandin for PCP is not warranted as withdrawal can result in return of the pneumonia. The results of the proposed studies will have immediate clinical relevance by determining the length of time viable Pneumocystis can remain in the lungs with concurrent anidulafungin treatment, providing a rationale for duration of therapy with eradication as the goal. They will also identify whether immunosuppressed mice can transmit the infection after withdrawal of anidulafungin and if there is a critical number of asci needed. The studies will also elaborate the life cycle of Pneumocystis and suggest new target strategies.

肺孢子虫属是导致致命性肺炎 (PCP) 的专性真菌病原体 免疫功能低下的宿主。很少有药物对 PCP 有效，并且目前还没有新的治疗方法 治疗几十年。通常，PCP 与感染 HIV 的患者有关，然而，暴发性的 肺炎、五氯苯酚和耶氏肺孢子菌（感染人类的​​物种）的定植正在出现 普通人群和退伍军人人群中新易感人群的临床问题，包括骨骼问题 骨髓受者；接受慢性免疫疗法治疗类风湿性关节炎和其他慢性病的患者 炎症性疾病；以及癌症化疗和免疫疗法。建议肺孢子虫的生命周期 包含无性复制周期和涉及交配以及随后形成的有性周期 asci 含有 8 个子囊孢子 (1)。在之前的优点评审中，我们表明棘白菌素治疗 感染 P. murina 和 P. carinii 的啮齿类动物，以 β-1,3-D-葡聚糖合成 (BG) 为目标，导致子囊细胞耗尽 含有 BG，但大量不表达 BG 的生命周期阶段仍保留在肺部，并被 无法增殖。我们进一步证明阿尼芬净和卡泊芬净可以预防感染 预防模型，表明通过性周期形成子囊对于生产性可能是必需的 感染（2）。对用阿尼芬净治疗的小鼠中的 P. murina 基因表达谱进行的分析表明， 与性复制相关的基因上调，尽管由此产生的感染没有子囊， 有性繁殖的产物，表明 P. murina 试图进行有性复制，但未能成功 由于缺乏BG。根据这些数据，我们认为需要 asci 以及性复制来促进 整个生命周期的进展导致生产性感染。我们进一步假设 asci 的存在是 传播肺孢子菌感染所需的。在本提案中，我们将探讨两个关键但 未解答的问题将导致对肺孢子虫生命周期有更深入的了解，并且还表明 阿尼芬净治疗联合靶向治疗的潜在弱点： (1)肺孢子菌的生命周期的完成是否需要有性复制？追踪 通过全局基因分析，BG 长期使用阿尼芬净治疗期间鼠鼠的复制状态 内容，显微镜方法将揭示非 BG 表达形式数量是否保持不变：1）静态 随着时间的推移，2) 增加，或 3) 减少；表明：1）BG 的缺乏会阻碍复制； 2）无性或 替代复制阶段允许真菌存活；或3）缺乏有性复制导致消除 的感染。 （2）长期阿尼芬净治疗停止后，性复制能否反弹？老鼠将会 用阿尼芬净治疗长达 8 周，有 2 个停止时间点。戒烟组中的小鼠将 追踪子囊形成和返回的显微镜、BG 含量和基因表达证据 肺炎，同时仍处于免疫抑制状态。治疗组和戒烟组的小鼠将 评估其传播感染的能力以及传播所需的关键 Asci 数量。全部 研究将在雄性和雌性小鼠中进行，将性别视为一个生物变量。 棘白菌素在美国已临床上市。目前使用任何棘白菌素的单一疗法 不建议使用 PCP，因为停药可能会导致肺炎复发。拟议研究的结果 通过确定活肺孢子虫可以在容器中保留的时间长度，将具有直接的临床意义 肺部与同时阿尼芬净治疗，提供了根除治疗持续时间的基本原理 目标。他们还将确定免疫抑制的小鼠在停药后是否可以传播感染。 阿尼芬净以及是否需要达到临界数量的 ASCI。研究还将详细阐述生命周期 肺孢子菌并提出新的目标策略。