Mechanisms of Candida auris skin colonization

耳念珠菌皮肤定植机制

基本信息

批准号：
10509882
负责人：
SUZANNE M NOBLE
金额：
$ 24.23万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-05-20 至 2024-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10509882
关键词：
Address Affinity Antibiotics Antifungal Agents Antifungal Antibiotics Biology CRISPR/Cas technology Candida albicans Candida auris Catheters Cell Wall Cell surface Centers for Disease Control and Prevention (U.S.)Characteristics Clinical Cues Data Defect Dermis Disease Drug resistance Environment Epidemiology Epidermis Exposure to Foundations Fungal Drug Resistance Gene Expression Regulation Genes Genetic Screening Genetic Transcription Goals Hair follicle structure Health care facility Histologic Hospitals Housing Human Immunosuppression In Vitro Infection Infectious Skin Diseases Inflammatory Interleukin-17 Interruption Intervention Intravenous Investigation Knock-out Lead Life MAP Kinase Signaling Pathways MAPK Signaling Pathway Pathway Mitogen-Activated Protein Kinase Kinases Modeling Molecular Mucins Mycoses Nursing Homes Operative Surgical Procedures Orthologous Gene Output Pathway interactions Patients Persons Phosphorylation Phosphotransferases Positioning Attribute Proteins Protocols documentation Recovery Regulon Risk Factors Role Signal Pathway Signal Transduction Skin Skin colonization Sodium Chloride Stress Surface Techniques Testing Transcriptional Activation Work Yeasts base cytokine drug resistant pathogen fungus gene repression high risk in vivo insight mouse model mutant novel opportunistic pathogen pathogen pathogenic fungus sensor skin damage trait transcriptome transcriptome sequencing transcriptomics transmission process

项目摘要

ABSTRACT C. auris is a relatively new opportunistic fungal pathogen that is spreading worldwide with high rates of intrinsic resistance to antifungal antibiotics and a strong affinity for human skin. It is now ranked by the CDC as the top drug-resistant fungal threat. Epidemiological analysis suggests that pathogen transmission occurs efficiently in shared housing environments such as hospitals or nursing homes. Importantly, person-to-person transmission of skin-associated yeasts appears to be a primary mode of spread. Although C. auris skin colonization is asymptomatic, life-threatening disease can arise in patients with additional risk factors, such as immunosuppression, intravenous catheter placement, surgery, and antibiotics. Understanding of the molecular mechanisms by which C. auris tenaciously colonizes the skin might offer potential opportunities to interrupt the infection cycle. Unfortunately, no molecules been identified that are important for host skin colonization. To begin to address this problem, we have established three mouse models of skin colonization and epicutaneous infection with Candida albicans that are suitable for investigations of C. auris. Using these models, we observe significantly higher titers of C. auris than C. albicans. Unlike C. albicans, C. auris fails to induce skin damage or to induce expression of the key antifungal pro-inflammatory cytokine, IL-17. Notably, C. auris displays clusters of yeast in the epidermis as well as invasion of the hair follicles, neither of which are seen with C. albicans. In a forward genetic screen of ~700 C. albicans null mutants, we identified four genes required for epicutaneous infection of skin. We disrupted the C. auris orthologs using a CRISPR/Cas9-based protocol. We found that all four mutant displayed defects in skin colonization in C. auris. Notably, two of the four genes encode C. auris orthologs of components of the HOG MAP kinase signaling pathway and are required for effective skin colonization in all three models. These data lead us to hypothesize that the HOG MAPK signaling pathway controls skin colonization in C. auris by controlling the expression of downstream target genes. We hypothesize that one or more of these target genes will be involved in promoting the ability of C. auris to effectively colonize the skin. We will test this high-risk/high-payoff hypothesis by 1) Investigating the role of the C. auris Hog1 pathway in skin colonization and establishing its role in gene regulation and 2) Identifying effectors of C. auris skin colonization. These studies have the potential to identify molecules and mechanisms required for C. auris to colonize the skin, a central aspect of the infection cycle of this important emerging drug-resistant pathogen. Having laid the groundwork, we are in a strong position to accomplish these goals, which we anticipate will provide a foundation to begin to obtain molecular insights into the unique biology of C. auris.

抽象的耳念珠菌 (C. auris) 是一种相对较新的机会性真菌病原体，正在全球范围内传播，其内在传播率很高。对抗真菌抗生素具有耐药性，对人体皮肤有很强的亲和力。现在被美国疾病预防控制中心（CDC）评为顶级耐药真菌的威胁。流行病学分析表明，病原体传播有效地发生在共享住房环境，例如医院或疗养院。重要的是人与人之间的传播皮肤相关酵母菌似乎是主要的传播方式。尽管耳念珠菌皮肤定植是具有其他危险因素的患者可能会出现无症状、危及生命的疾病，例如免疫抑制、静脉导管放置、手术和抗生素。对分子的理解耳念珠菌在皮肤上顽强定殖的机制可能会提供潜在的机会来中断感染周期。不幸的是，没有发现对宿主皮肤定植重要的分子。开始为了解决这个问题，我们建立了三种皮肤定植和表皮定植的小鼠模型适合研究耳念珠菌的白色念珠菌感染。使用这些模型，我们观察到耳念珠菌的滴度明显高于白色念珠菌。与白色念珠菌不同，耳念珠菌不会引起皮肤损伤或诱导关键抗真菌促炎细胞因子 IL-17 的表达。值得注意的是，耳念珠菌显示集群表皮中的酵母菌以及毛囊的侵袭，这两种情况在白色念珠菌中都未见。在一个对约 700 个白色念珠菌无效突变体进行正向遗传筛选，我们鉴定了表皮所需的四个基因皮肤感染。我们使用基于 CRISPR/Cas9 的方案破坏了 C. auris 直向同源物。我们发现所有四种突变体在耳念珠菌的皮肤定植中表现出缺陷。值得注意的是，四个基因中的两个编码耳念珠菌 HOG MAP 激酶信号通路成分的直系同源物，是有效皮肤所必需的所有三种模型中的殖民化。这些数据使我们推测 HOG MAPK 信号通路通过控制下游靶基因的表达来控制耳念珠菌的皮肤定植。我们假设这些目标基因中的一个或多个将参与促进耳念珠菌有效定殖的能力皮肤。我们将通过 1) 调查 C. auris Hog1 的作用来检验这一高风险/高回报的假设皮肤定植途径并确定其在基因调控中的作用，2) 识别耳念珠菌效应子皮肤定植。这些研究有可能确定耳念珠菌所需的分子和机制在皮肤上定殖，这是这种重要的新兴耐药病原体感染周期的核心部分。奠定了基础后，我们就有能力实现这些目标，我们预计这些目标将实现为开始获得对耳念珠菌独特生物学的分子见解提供了基础。