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.

肺孢子虫属是专性真菌病原体，可导致致命性肺炎（PCP）， 免疫受损的宿主很少有药物对PCP有效，也没有新的治疗方法。 几十年的治疗。通常，PCP与感染HIV的患者有关，然而，雷酸盐 肺炎、PCP和耶氏肺孢子虫（感染人类的物种）的定植正在出现 一般人群和退伍军人人群中新易感人群的临床问题，包括骨 骨髓接受者;接受类风湿性关节炎和其他慢性免疫疗法的患者 炎性疾病;以及癌症化疗和免疫疗法。提出了肺孢子虫的生活史 包含无性复制周期和涉及交配并随后形成的性周期 子囊内有8个子囊孢子（1）。在之前的Merit审查中，我们表明棘白菌素治疗 感染以β-1，3-D-葡聚糖合成（BG）为靶点的鼠疟原虫和卡氏疟原虫的啮齿动物， 其含有BG，但大量的非BG表达生命周期阶段保留在肺中， 无法扩散。我们进一步证明阿尼芬净和卡泊芬净可以预防感染， 预防性模型，表明通过性周期形成asci可能是生产性的， 感染（2）。阿尼芬净处理小鼠中鼠疟原虫的基因表达谱分析显示， 与性复制相关的基因表达上调，尽管由此产生的感染没有asci， 这表明P. murina试图进行有性复制，但不能 因为缺乏BG。基于这些数据，我们认为asci，因此性复制，是需要促进 通过生命周期的进展导致生产性感染。我们进一步证实，ASCI的存在是 肺孢子虫感染的传播所需的。在本提案中，我们将探讨2个关键，但 未回答的问题，这将导致肺孢子虫的生命周期更深入的了解，也建议 阿尼芬净治疗伴随的靶向治疗的潜在脆弱性： (1)性复制是肺孢子虫完成生命周期所必需的吗？跟踪 通过全局基因分析，BG法研究阿尼芬净长期治疗期间鼠疟原虫的复制状态 内容，显微镜方法将揭示非BG表达形式的数量是否保持：1）静态 随着时间的推移，2）增加，或3）减少;这表明：1）缺乏BG阻止复制; 2）无性或 交替的复制阶段允许真菌存活;或3）缺乏有性复制导致消除 感染 (2)停止阿尼芬净长期治疗后，性复制是否会反弹？小鼠将被 用阿尼芬净治疗长达8周，有2个停止时间点。停止组中的小鼠将 跟踪显微镜下，BG含量和基因表达证据的腹水形成和返回的 肺炎，同时保持免疫抑制。治疗组和停药组的小鼠将被 评估它们传播感染的能力和传播所需的ASCI临界数量。所有 将在雄性和雌性小鼠中进行研究，将性别视为一种生物变量。 棘白菌素在美国临床上可用。目前接受任何棘白菌素单药治疗 因为停药可能导致肺炎复发，所以不需要使用PCP。拟议研究的结果 通过确定活肺孢子虫可以在体内停留的时间长度， 肺合并阿尼芬净治疗，为根除治疗的持续时间提供了依据， 目标.他们还将确定免疫抑制小鼠在停药后是否会传播感染。 阿尼芬净和是否需要临界数量的ASCI。这些研究还将详细说明 肺孢子虫并提出新的目标策略。