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: 10421251
• 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/10421251
• 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 Pulmonary 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.

肺孢子菌是引起致命性肺炎 (PCP) 的专性真菌病原体。 很少有药物对免疫功能低下的宿主有效，并且目前还没有针对其的新疗法。 通常，PCP 与感染 HIV 的患者有关，但暴发性的。 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 骨髓接受者；接受类风湿性关节炎和其他慢性病的长期免疫治疗的患者 建议采用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 含有 8 个子囊孢子的子囊 (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 的啮齿动物，其目标是 β-1,3-D-葡聚糖合成 (BG)，耗尽了子囊 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 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 对用阿尼芬净治疗的小鼠中的 P. murina 感染进行的基因表达谱分析显示出很强的感染力。 与性复制相关的基因上调，尽管由此产生的感染没有子囊细胞（asci） 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，基于这些数据，我们认为需要 asci 以及有性复制来促进。 我们进一步推测，asci 的存在是导致生产性进展感染的整个生命周期。 在目前的建议中，我们将探讨 2 个关键但但传播肺孢子虫感染所需的条件。 未解答的问题将导致对肺孢子虫的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) 肺孢子虫的生命周期的完成是否需要有性复制？ 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) 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) 停止长期阿尼芬净治疗后，小鼠性复制会反弹吗？ 用阿尼芬净治疗长达8周，停药组中的小鼠将有2个停药时间点。 追踪子囊形成和返回的微观、BG 含量和基因表达证据 处于免疫抑制状态下的小鼠将出现肺炎。 评估其传播感染的能力以及传播所需的关键数量。 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。 目前，棘白菌素在美国可用于任何棘白菌素的单一疗法。 不保证 PCP 的治疗，因为停药可能导致肺炎复发。拟议研究的结果 通过确定活的肺孢子菌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 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一定数量的 asci，这些研究还将详细阐述其生命周期。 肺孢子菌并提出新的目标策略。