The role of a pleiotropic drug resistance (PDR) transporter in the cryptococcal-host interactions

多效性耐药（PDR）转运蛋白在隐球菌-宿主相互作用中的作用

• 批准号: 10593492
• 负责人: Felipe H Santiago-Tirado
• 金额: $ 23.48万
• 依托单位: UNIVERSITY OF NOTRE DAME
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-11-11 至 2024-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10593492
• 关键词: ATP-Binding Cassette Transporters; Address; Affect; Africa; Amino Acid Sequence; Animals; Antifungal Agents; Antimicrobial Resistance; Applications Grants; Area; Attenuated; Binding; Biological Assay; Cell membrane; Cell model; Cell physiology; Cell surface; Cells; Cessation of life; Clinical; Clinical Research; Clinical Treatment; Complex; Cryptococcosis; Cryptococcus; Cryptococcus neoformans; Data; Developing Countries; Development; Dimerization; Disease; Disease Management; Disease Outcome; Disease Progression; Drug resistance; Endoplasmic Reticulum; Ergosterol; Europe; Exhibits; Family; Fluconazole; Fluconazole resistance; Fungal Drug Resistance; Fungal Genes; Future; Genes; Goals; Homologous Gene; Hypersensitivity; Immune response; Immunocompromised Host; Incidence; Individual; Infection; Intervention; Knowledge; Left; Light; Lung; Macrophage; Medical; Mission; Modeling; Mycoses; National Heart, Lung, and Blood Institute; National Institute of Allergy and Infectious Disease; Organism; Outcome; Pathogenesis; Pathogenicity; Phagocytes; Phagocytosis; Pharmaceutical Preparations; Phenotype; Plasma; Play; Population; Predisposition; Process; Protein Sequence Analysis; Public Health; Regulation; Relapse; Research; Resistance profile; Role; Southeastern Asia; Steroids; Testing; Therapeutic; Toxic effect; Transmembrane Transport; United States National Institutes of Health; Virulence; Work; Yeasts; anticancer treatment; attenuation; cost; effective therapy; efflux pump; fungus; gene function; human disease; improved; in vivo; insight; low income country; mortality; mouse model; mutant; novel; overexpression; pathogenic fungus; prevent; resistance gene; response; synergism

PROJECT SUMMARY / ABSTRACT Cryptococcus neoformans is one of the most common fungal pathogens, responsible for over 200,000 deaths yearly, mostly in the immunocompromised. Unfortunately, due to medical advances such as chemother- apy or steroid treatments, this population of susceptible individuals is increasing. Despite the increasing burden of cryptococcal disease, there are only three clinically available therapeutics, and they are plagued by cost, toxicity, and recently, antifungal resistance. Making the situation even more challenging, the pathogenesis of Cryptococcus is incompletely understood, limiting the number of potential targets or processes that could be used as intervention points. All of this has resulted in a mortality rate that ranges from ~20% in the US and Europe, to >71% in Africa and Southeast Asia. Therefore, there is a clear need to improve the current anticryp- tococcal drugs and to better understand the fungal-host interactions, which could lead to novel and more effective treatments. This application addresses both of these needs. The fungal-host interactions, particularly the inter- actions with the lung macrophages, will determine the outcome of the infection. While investigating the interactions between cryptococci and macrophages, we identified an uncharacterized fungal gene that affects phagocytosis by macrophages. Analysis of the amino acid sequence of this gene, which we are calling PDR6, shows that it contains all the features of ABC transporters of the PDR family, which are usually efflux pumps. Consistently, this mutant is hypersensitive to fluconazole, the mainstay treatment for cryptococcosis, and shows an altered antifungal profile relative to wild-type. Notably, infection of a murine model with this mutant results in attenuation and altered progression of the disease. This proposal is organized to study these two phenotypes: altered antifungal responses (Aim 1) and altered virulence and host interactions (Aim 2). Hence, we are tackling the two general problems that are currently preventing an appropriate management of this disease. In Aim 1 we will elucidate the function of Pdr6 and determine how it affects the sensitivity of the cell to fluconazole and other antifungals. In Aim 2 we will identify the Pdr6-dependent changes in the fungal cell and the host that result in altered host interactions and attenuated virulence. These two aims, although independent, are complimentary, and will be performed in parallel. Completion of the aims proposed will result in a significant advancement of both (1) our understanding of ABC transporter functions in general, and specifically in Cryptococcus, and (2) our understanding of fungal-host interactions and their contribution to virulence. These results will synergize with the other projects in the lab, and will open multiple new directions of research that will be used for future grant applications. Interestingly, close homologs of PDR6 are present in many pathogenic fungi, but are absent from the model non-pathogenic ones, hence the discoveries here will have broad impact in the fungal field.

项目摘要 /摘要 加密赛车是最常见的真菌病原体之一，负责超过200,000 每年死亡，主要是在免疫功能低下。不幸的是，由于医学的进步，例如化学 APY或类固醇治疗，这种易感人群正在增加。尽管负担增加了 在隐球菌疾病中，只有三种临床上可用的治疗药，它们因成本困扰， 毒性，以及最近的抗真菌抗性。使情况更具挑战性，发病机理 加密赛未完全理解，限制了可能是的潜在目标或过程的数量 用作干预点。所有这些都导致死亡率在美国约20％不等， 欧洲，在非洲和东南亚> 71％。因此，显然需要改善当前的抗晶 造物菌药物并更好地了解真菌 - 宿主相互作用，这可能导致新颖，更有效 治疗。该应用程序解决了这两个需求。真菌宿主相互作用，特别是 肺巨噬细胞的作用将决定感染的结果。在调查 加密环球与巨噬细胞之间的相互作用，我们确定了一个未表征的真菌基因 巨噬细胞的吞噬作用。分析该基因的氨基酸序列，我们称之为PDR6， 表明它包含PDR家族的ABC转运蛋白的所有特征，这些特征通常是外排泵。 一致地，该突变体对氟康唑高度敏感，氟康唑是隐孢子球病的主要治疗方法，并显示 相对于野生型的抗真菌特征改变。值得注意的是，具有这种突变体的鼠模型的感染导致 疾病的衰减和变化。该提案的组织以研究这两种表型： 改变抗真菌反应（AIM 1）并改变了毒力和宿主相互作用（AIM 2）。因此，我们正在解决 目前阻止对该疾病进行适当管理的两个一般问题。在目标1中我们 将阐明PDR6的功能，并确定其如何影响细胞对氟康唑和其他细胞的敏感性 抗真菌。在AIM 2中，我们将确定真菌细胞中的PDR6依赖性变化和导致的宿主 宿主相互作用改变和毒力减弱。这两个目标虽然是独立的，但是免费的 并将并行执行。提出的目标的完成将导致重大进步 （1）我们对ABC转运蛋白功能的理解一般，特别是在加密环球中，以及（2）我们的 了解真菌 - 宿主相互作用及其对毒力的贡献。这些结果将与 实验室中的其他项目，并将打开多个新的研究方向，这些方向将用于未来赠款 申请。有趣的是，PDR6的紧密同源物存在于许多致病性真菌中，但没有 因此，非致病模型的发现将在真菌领域产生广泛的影响。