Environmental Conditions Control Filamentation and Virulence in Candida albicans

环境条件控制白色念珠菌的丝状结构和毒力

• 批准号: 8261055
• 负责人: Delma Childers
• 金额: $ 1.33万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8261055
• 关键词: Address; Adverse effects; Antifungal Agents; Antifungal Therapy; Binding; Binding Sites; Biological Assay; Candida albicans; Candidiasis; Carbon; Cells; Chronic Disease; Cutaneous; Cytolysis; Data; Development; Drug Delivery Systems; Electrophoretic Mobility Shift Assay; Elements; Environment; Exposure to; Feedback; Filament; Frequencies; Fungal Drug Resistance; Gene Expression; Genes; Genetic Transcription; Goals; Growth; HIV; Human; Hybrids; Immunocompromised Host; In Vitro; Industrial fungicide; Infection; Invaded; Knowledge; LacZ Genes; Location; Mass Spectrum Analysis; Medical; Morphogenesis; Mycoses; NRG1 gene; Nitrogen; Oral candidiasis; Oral mucous membrane structure; Organism; Pathogenicity; Phagocytosis; Play; Property; Proteins; Recording of previous events; Recurrence; Regulation; Reporter; Reporter Genes; Research; Response Elements; Role; Serum; Signal Transduction Pathway; Starvation; Stimulus; System; Systemic infection; The science of Mycology; Training; Transcriptional Regulation; Virulence; Virulence Factors; Work; Yeasts; base; compliance behavior; deletion analysis; insight; macrophage; novel; oral fungal; pandemic disease; pathogen; promoter; public health relevance; resistant strain; response; trait; transcription factor

DESCRIPTION (provided by applicant): Candida albicans is the leading cause of oral candidiasis worldwide. The ability to undergo a reversible transition from yeast (ovoid, budding cells) to hyphal filaments (elongated cells attached end-to-end) is a key virulence trait that allows C. albicans to be a successful opportunistic pathogen. The transition to filaments is co-regulated with other virulence factors and occurs in response to several host environmental conditions including 370C, serum, carbon/nitrogen starvation and neutral pH. Exposure to these growth conditions activates numerous signal transduction pathways that promote virulence-related gene expression and hyphal growth, but little is known about the mechanisms that control the expression and activity of filament-specific transcription factors. Although antifungal therapies are available to treat candidiasis, many antifungal drugs have adverse side effects and are fungistatic, not fungicidal. The long term goal of our studies is to gain insight into morphogenesis to identify novel antifungal drug targets. Our objective is to understand how C. albicans regulators of filamentation respond to environmental stimuli via transcriptional and posttranslational mechanisms. Our studies will focus on Ume6, Nrg1 and Rfg1, key transcription factors that regulate hyphal- specific gene expression and filamentation. We hypothesize that environmental filament-inducing conditions differentially control the transcriptional regulation and activity of Ume6, Nrg1 and Rfg1. We propose the following Specific Aims to address our hypothesis: Specific Aim 1: Determine the mechanism(s) by which UME6 and NRG1 are transcriptionally regulated in response to environmental filament-inducing conditions. Specific Aim 2: Determine the transcriptional activity of Ume6, Nrg1 and Rfg1 in response to several environmental conditions. In order to address Aim 1, we will use a promoter deletion analysis with a lacZ reporter assay, electrophoretic mobility shift assays and mass spectrometry to identify the transcriptional regulators that control NRG1 and UME6 expression in response to specific environmental stimuli. To address Aim 2, we will use a one-hybrid system with a lacZ reporter gene to investigate the transcriptional activity of Ume6, Nrg1 and Rfg1 in response to environmental conditions. We will use RT-qPCR in both Aims to quantify lacZ expression. At the completion of our studies, we expect to have a better understanding of the environmental regulation of C. albicans morphogenesis, which will aid in the development of new antifungal therapies. PUBLIC HEALTH RELEVANCE: Candida albicans is the leading cause of oral fungal infections worldwide due, in part, to the global HIV pandemic. Our studies will provide insight into a key virulence factor, the ability to switch between yeast and filamentous forms, which makes this organism a successful opportunistic pathogen. This knowledge will aid in the development of new antifungal therapies.

描述（由申请人提供）：白色念珠菌是全球口腔念珠菌病的主要原因。从酵母（卵形，出现细胞）到菌丝丝（端到端附着的细长细胞）进行可逆过渡的能力是一种关键的毒力性状，它允许白色念珠菌成为成功的机会性病原体。向细丝的过渡与其他毒力因子共同调节，并响应几种宿主环境条件，包括370C，血清，碳/氮饥饿和中性pH。暴露于这些生长条件会激活许多促进毒力相关基因表达和菌丝生长的众多信号转导途径，但对控制细丝特异性转录因子的表达和活性的机制知之甚少。尽管可用于治疗念珠菌病的抗真菌疗法，但许多抗真菌药物具有不良的副作用，并且是fungistatic的，而不是杀真菌的。我们研究的长期目标是洞悉形态发生，以鉴定新的抗真菌药物靶标。我们的目的是了解白色念珠菌的细丝调节剂如何通过转录和翻译后机制对环境刺激做出反应。我们的研究将重点介绍UME6，NRG1和RFG1，即调节菌丝特定基因表达和细丝的关键转录因子。我们假设诱导环境丝的条件差异地控制了UME6，NRG1和RFG1的转录调控和活性。我们提出以下具体目的旨在解决我们的假设：具体目的1：确定响应于环境丝状条件的响应于环境丝状条件的转录调节的UME6和NRG1的机制。特定目标2：确定响应几种环境条件的UME6，NRG1和RFG1的转录活性。 为了解决目标1，我们将使用LACZ报告基因测定法，电泳移动性转移测定法和质谱法使用启动子缺失分析，以识别控制NRG1和UME6表达的转录调节剂，以响应特定的环境刺激。为了解决AIM 2，我们将使用具有LACZ报告基因的一个杂交系统来研究UME6，NRG1和RFG1的转录活性，以响应环境条件。我们将使用RT-QPCR来量化LACZ表达。研究完成后，我们希望更好地了解白色念珠菌形态发生的环境调节，这将有助于开发新的抗真菌疗法。 公共卫生相关性：白色念珠菌是全球口腔真菌感染的主要原因，部分原因是全球艾滋病毒大流行。我们的研究将洞悉关键的毒力因子，即在酵母和丝状形式之间切换的能力，这使该生物成为成功的机会性病原体。这些知识将有助于开发新的抗真菌疗法。