Genetic and mechanistic analysis of carbon dioxide tolerance in Cryptococcus pathogenesis

隐球菌发病机制中二氧化碳耐受性的遗传和机制分析

基本信息

批准号：
10548836
负责人：
Damian J Krysan
金额：
$ 63.08万
依托单位：
UNIVERSITY OF IOWA
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-02-18 至 2025-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10548836
关键词：
Affect Air Anabolism Biological Carbon Carbon Dioxide Cessation of life Clinical Cryptococcal Meningitis Cryptococcus Cryptococcus neoformans DNA Sequence Alteration Data Disease Drug Targeting Environment Event Evolution Future Gene Expression Profile Genes Genetic Genetic Polymorphism Genetic Screening Genetic Transcription Genomic approach Genomics Genotype Glycolysis Goals Growth HIV antiretroviral HIV diagnosis HIV therapy HIV/AIDS High temperature of physical object Homeostasis Human In Vitro Incidence Infection Lung Maps Meningoencephalitis Metabolism Minority Modeling Molecular Molecular Target Mus Mutation Opportunistic Infections Outcome Pathogenesis Pathway interactions Patients Persons Phenotype Positioning Attribute Property Publishing Quantitative Trait Loci Resource-limited setting Role Sentinel Sphingolipids Symptoms Testing Tumor Biology Variant Virulence Virulent Yeasts antiretroviral therapy burden of illness capsule deletion library design differential expression experience experimental study fitness genetic resource genome wide association study improved inhibitor mortality mouse model mutant new therapeutic target novel anticancer drug novel therapeutics pathogenic fungus patient population response trait transmission process

项目摘要

Abstract Cryptococcal meningoencephalitis (CME) is one of the most important opportunistic infections affecting people with HIV/AIDS. The importance of this disease is due not only to its high incidence and mortality in this and other patient populations but also to the fact that symptoms of CME are a common sentinel event leading to the diagnosis of HIV/AIDS. Thus, many patients must first survive CME before they can benefit from the advances in HIV therapy. Unfortunately, the outcomes for CME therapy are far from acceptable, particularly in resource-limited regions with high burdens of disease. Consequently, effective and widely available therapies for CME are an unmet clinical need of global importance. Cryptococcus spp. are basidiomycetous yeasts whose primary niche is the external environment. As such, only strains and species of Cryptococcus that can transition to, and replicate within, the human host are able to cause disease. Our central premise is that an understanding of the biological mechanisms required for Cryptococcus to survive in human beings could provide new targets for therapy in the same way as studying tumor biology informs the design of new anti- cancer drugs. An important environmental distinction between the human host and the natural niche of Cryptococcus is the concentration of carbon dioxide (CO2). We hypothesized that adaptation to host levels of CO2 may represent a critical step in Cryptococcus pathogenesis. To specifically test this hypothesis, we compared the growth of C. neoformans var. grubii strains under conditions that varied only in the concentration of CO2. Consistent with our hypothesis, the growth rate was reduced at concentrations of CO2 experienced in the host. Next, we tested the CO2 tolerance of a set of environmental strains with known virulence properties in a mouse model; strains with reduced growth in the presence of host concentrations of CO2 were avirulent while those with growth rates that matched clinical isolates from human patients were virulent. We, therefore, have discovered that CO2 tolerance is a previously unrecognized host environment-associated virulence attribute of C. neoformans. Accordingly, the goal of this proposal is to identify the genetic, transcriptional, and regulatory responses that allow specific strains of C. neoformans to respond to host concentrations of CO2 and, thereby, cause CME. To accomplish these goals, we propose the following specific aims: Aim 1. Characterize the virulence, transcriptional, and genomic distinctions between CO2- tolerant and -non-tolerant C. neoformans strains; Aim 2. Identify genes required for CO2 tolerance through targeted and large-scale genetic screening; and Aim 3. Determine the molecular mechanisms of genes required for C. neoformans CO2 response. Successful execution of these aims will not only further our understanding C. neoformans pathogenesis and host survival but also identify new molecular targets for future exploration as drug targets.

抽象的隐球菌脑膜脑炎（CME）是影响人们的最重要的机会感染之一与艾滋病毒/艾滋病。这种疾病的重要性不仅归因于其在此疾病的高发病率和死亡率以及其他患者人群，但同时也是CME症状是一个常见的前哨事件，导致艾滋病毒/艾滋病的诊断。因此，许多患者必须先在CME中生存，然后才能从中受益艾滋病毒疗法的进步。不幸的是，CME治疗的结果远非可以接受的，尤其是在疾病负担高的资源有限地区。因此，有效且可用的疗法因为CME是全球重要性的未满足的临床需求。加密环球属。是基础菌酵母其主要利基是外部环境。因此，只有可以过渡到并在内部复制人类宿主能够引起疾病。我们的中心前提是了解隐孢菌在人类中生存所需的生物学机制可能提供与研究肿瘤生物学相同的方式提供新的治疗靶标的癌症药物。人类宿主与自然利基之间的重要环境区别加密环球是二氧化碳（CO2）的浓度。我们假设适应宿主的水平二氧化碳可能代表了加密汽车发病机理的关键步骤。为了具体检验这一假设，我们比较了Neoformans C. var的生长。在仅在浓度下变化的条件下的grubii菌株二氧化碳。与我们的假设一致，在经历的二氧化碳浓度下降低了增长率主人。接下来，我们测试了具有已知毒力特性的一组环境菌株的二氧化碳公差在鼠标模型中；在宿主浓度存在二氧化碳浓度的情况下，生长降低的菌株是无毒的而那些与人类患者的临床分离株相匹配的增长率的人是有毒的。因此，我们已经发现二氧化碳公差是先前未识别的宿主环境相关的梭状芽胞杆菌的毒力属性。因此，该提议的目的是确定遗传，转录和调节反应，允许特定菌株的新旋转梭菌对宿主做出反应二氧化碳的浓度，从而导致CME。为了实现这些目标，我们建议以下具体目的：目标1。表征CO2-之间的毒力，转录和基因组区别耐受性和耐受性梭状芽胞杆菌菌株；目标2。通过通过靶向和大规模的基因筛查；和目标3。确定基因的分子机制 Neoformans Co2响应所需。这些目标的成功执行不仅将进一步了解C. Neofars发病机理和宿主存活率，但也确定了未来的新分子靶标作为药物靶标的探索。