Mechanisms of Fluconazole-Induced Aneuploidy in Cryptococcus Neoformans

 描述(由申请人提供)：真菌是免疫能力和免疫功能低下患者死亡和发病的一个日益重要的原因。由新生隐球菌引起的隐球菌性脑膜炎是世界上最常见的真菌中枢神经系统感染的原因。100万例隐球菌感染发生在全球，主要与艾滋病有关，占所有与艾滋病有关的死亡人数的三分之一。尽管存在这些公共卫生威胁，但对隐球菌病的有效治疗是不够的。最近的报道表明，基因组可塑性在新生葡萄球菌的致病性中具有重要意义。例如，染色体拷贝数的变化是导致体内和体外对唑类药物氟康唑产生耐药性的主要因素。在对氟康唑耐药的新生葡萄球菌分离株中，拷贝数增加的关键耐药基因的名单已经确立。然而，人们对这种生物中控制染色体拷贝数变化的分子机制知之甚少。这项建议的主要目的是阐明当新生葡萄球菌暴露于氟康唑时导致非整倍体产生的机制。我们将详细分析氟康唑对细胞生长和核分裂的影响。此外，我们还将阐明新生葡萄球菌纺锤体组装检查点(SAC)途径的基本结构，并探讨该途径的抑制可能是氟康唑触发的非整倍体导致耐药的原因之一。这项工作将有助于我们理解真菌病原体在感染过程中染色体变化的机制。这个项目将吸引研究生和本科生，并允许实践研究经验。学生将接触到各种实验室技术，并将学习制定和测试研究假设。

 DESCRIPTION (provided by applicant): Fungi are an increasingly important cause of death and morbidity in both immunocompetent and immunocompromised patients. Cryptococcal meningitis caused by Cryptococcus neoformans is the most common cause of fungal central nervous system infection in the world. One million cases of Cryptococcal infection occur globally, largely in the context of AIDS and constitute one-third of all AIDS-associated deaths. Despite these public health threats, effective treatments for cryptococcosis are inadequate. Recent reports indicate a high importance of genome plasticity in the pathogenicity of C. neoformans. For example, changes in chromosomal copy number are a major factor contributing to the resistance to the azole drug fluconazole in vitro and in vivo. The list of key resistance genes whose copy number increases in fluconazole-resistant C. neoformans isolates is well established. However, very little is known about the molecular mechanisms that govern changes in chromosomal copy number in this organism. The main objective of this proposal is to elucidate mechanisms responsible for generation of aneuploidy when C. neoformans is exposed to fluconazole. We will perform a detailed analysis of the effects of fluconazole on cell growth and nuclear division. In addition, we will elucidate basic architecture of the spindle assembly checkpoint (SAC) pathway in C. neoformans, and explore the possibility that the inhibition of this pathway is one of the causes of fluconazole-triggered aneuploidy leading to drug resistance. This work will contribute to our understanding of the mechanisms that are involved in chromosomal changes of a fungal pathogen during infection. This project will engage graduate and undergraduate students and allow for hands-on research experience. Students will be exposed to various laboratory techniques and will learn formulating and testing research hypotheses.