The role of sex in the life cycle and transmission of Pneumocystis

肺孢子虫。致命性肺炎(PCP)是宿主专性真菌病原体吗？ 免疫功能受损的宿主。很少有药物对PCP有效，也没有新的治疗方法 几十年来的治疗。PCP仍然是艾滋病毒感染患者的一个问题，并在#年成为临床关注的问题。 新的易感人群包括接受慢性病免疫治疗的患者。 我们最近报道了用棘球菌素治疗小鼠PCP模型，棘球菌素是一种抗真菌药物， 靶β-1，3-D-葡聚糖合成(BG)，耗尽了含有BG的ASCI，但大量的 未表达的BG仍留在感染的肺中，明显不能增殖。值得注意的是，接受治疗的 如果没有ASCI，小鼠不能传播感染。棘球菌素在给药时可预防PCP 更高剂量的预防性，表明ASCI的形成可能需要通过性周期 生殖性感染。与有性复制和细胞周期紊乱相关的基因包括 阿尼杜拉芬净处理的小鼠体内最强的上调信号。这些感染没有发现 ASCI，表明P.Murina试图进行有性复制，但由于缺乏BG而失败。 基于这些数据，我们假设ASCI，从而性复制，是通过 肺孢子虫的生命周期。性周期对肺孢子虫生存的重要性将是 采用阿尼杜拉芬净治疗和预防模型进行研究。具体目标涉及2个主要方面 我们建议探讨的问题：问题1：生命周期的完成是否需要有性复制 肺孢子虫？3个AIMS将用来解决这个问题。第一个任务是评估复制 用阿尼杜拉芬净处理后，将其转移到新寄主上。复制将是 通过显微方法、血糖测量和定量聚合酶链式反应相结合的方法进行测定。第二 AIM将使用预防性模型来允许低水平复制，以询问复制是否通过有性繁殖发生 循环，使用相同的方法。第三个目标将决定P.Murina能否在长时间内存活 在相同的宿主中进行anidulafungin治疗而不进行性周期或如果最终是 通过了。问题2：在肺孢子虫生命周期的哪个时间点可以传播感染？这个 停用阿尼杜拉芬净后，性周期恢复。在停药后的10天至4周内，我们将跟踪 性周期的出现和确定ASCI之前的基因特征、生物标记物和数量 将这些老鼠暴露在幼稚的接受者面前。使用这些数据，我们将确定生命周期中的哪个时间点 传输发生时，传输所需的阈值。基于基因的精选蛋白质 表达数据将被蛋白质组学验证为与性行为回归相关的潜在生物标记物 循环和传输。这些研究将确定肺孢子虫生命周期中的潜在脆弱性 可以被利用来阻断，并增加我们对其生命周期和传播的了解。

Pneumocystis spp. are host 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. PCP remains a problem in HIV-infected patients and is emerging as a clinical concern in newly susceptible populations including patients receiving immunotherapy for chronic conditions. We recently reported that treatment of PCP in murine models with the echinocandins, anti-fungal agents that target β-1,3-D-glucan synthesis (BG), depleted the asci which contain BG, but large numbers of forms that do not express BG remained in the infected lungs and were apparently unable to proliferate. Notably, the treated mice could not transmit the infection without asci. The echinocandins prevented PCP when administered prophylactically at higher doses, suggesting that formation of asci via the sexual cycle may be required for a productive infection. Genes associated with sexual replication and cell cycle perturbation comprised the strongest up-regulated signals in P. murina from anidulafungin treated mice. These infections were devoid of asci, 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 for progression through the Pneumocystis life cycle. The importance of the sexual cycle for survival of Pneumocystis will be investigated using the anidulafungin treatment and prophylactic models. The specific aims address 2 major questions we propose to pursue: Question 1: Is sexual replication required for completion of the life cycle of Pneumocystis? 3 aims will be used to address this question. The first will be to assess the replication competency of P. murina treated with anidulafungin by transferring them to new hosts. Replication will be determined by a combination of microscopic methods, BG measurement, and quantitative PCR. The second aim will use the prophylactic model to allow low level replication to ask whether replication occurs via the sexual cycle, using the same methods. The third aim will determine whether P. murina can survive during prolonged anidulafungin treatment in the same hosts without proceeding through the sexual cycle or if it is eventually cleared. Question 2: At what point in the Pneumocystis life cycle can the infection be transmitted? The sexual cycle returns after withdrawal of anidulafungin. During 10 days to 4 weeks post-cessation, we will track the emergence of the sexual cycle and identify gene signatures, biomarkers and numbers of asci prior to exposing these mice to naïve recipients. Using these data, we will determine at what point in the life cycle transmission takes place and the thresholds necessary for transmission. Selected proteins based on gene expression data will be validated by proteomics as potential biomarkers associated with return of the sexual cycle and transmission. These studies will identify potential vulnerabilities in the Pneumocystis life cycle that could be exploited for interdiction and add to our understanding of its life cycle and transmission.