Candida albicans responses to antifungals and cell wall stress

白色念珠菌对抗真菌药物和细胞壁应激的反应

• 批准号: 8633820
• 负责人: CORNELIUS J CLANCY
• 金额: --
• 依托单位: VETERANS HEALTH ADMINISTRATION
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8633820
• 关键词: 3-Dimensional; Anidulafungin; Antibiotics; Antifungal Agents; Antifungal Therapy; Area; Attenuated; Candida; Candida albicans; Candidiasis; Caspofungin; Catheters; Cell Wall; Cell membrane; Cells; Chemotherapy-Oncologic Procedure; Clinical; Diagnostic tests; Disseminated candidiasis; Drug Exposure; Employee Strikes; Environment; Enzymes; Equilibrium; Failure; Fluorescence Recovery After Photobleaching; Fluorescence Resonance Energy Transfer; Fungal Drug Resistance; Gastrointestinal Surgical Procedures; Gene Expression; Goals; Guanine; Guanine Nucleotide Exchange Factors; Health; Host Defense; Human; In Vitro; Industrial fungicide; Infection; Intra-abdominal; Intravenous; Investigation; Kidney Failure; Life; Link; MAP Kinase Gene; Methods; Micafungin; Modeling; Molecular; Molecular Profiling; Morphogenesis; Mus; Nature; Neutropenia; Output; Pathogenesis; Pathway interactions; Patients; Pattern; Phosphatidylinositols; Phosphoric Monoester Hydrolases; Phosphotransferases; Predisposition; Process; Regulation; Research; Resistance; Risk Factors; Sepsis; Series; Signal Transduction; Site; Stress; Techniques; Time; Veterans; Virulence; Virulence Factors; candidemia; cellular imaging; effective therapy; glucan synthase; immunosuppressed; improved; in vivo; innovation; insight; mortality; mouse model; mutant; novel; pathogen; public health relevance; response; transcription factor; transcriptome sequencing

Candidemia, the fourth most common bloodstream infection in the U.S., and other forms of systemic candidiasis are associated with mortality rates of 40% or more despite treatment with antifungal agents. The Candida albicans cell wall is central to the pathogenesis of candidiasis, but mechanisms that link cell wall regulation and virulence are only beginning to be understood. Recently, we demonstrated that C. albicans rapidly delocalizes phosphatidylinositol-(4,5)-bisphosphate (PI(4,5)P2) and septins as part of the natural response to the cell wall-active antifungal caspofungin. Furthermore, we identified a novel C. albicans PI(4,5)P2-septin pathway that regulates cell wall integrity and virulence among mice with candidiasis. We hypothesize that the ability to activate or down-regulate the PI(4,5)P2-septin pathway as dictated by the environment (i.e., balanced regulation) is necessary for optimal C. albicans responses to cell wall stress during drug exposure or invasive candidiasis. The objectives of this project are to prove our balanced regulation hypothesis, validate the proposed PI(4,5)P2-septin pathway, and identify its outputs. We will pursue three specific aims. The first aim is to demonstrate that balanced PI(4,5)P2 regulation correlates with protective responses to caspofungin. Dynamic PI(4,5)P2 responses will be correlated with cellular viability in PI(4,5)P2- regulatory mutants and caspofungin-susceptible and -resistant C. albicans strains. The second aim is to establish interactions between PI(4,5)P2 and other PI(4,5)P2-septin pathway components during caspofungin exposure and invasive candidiasis. Interactions will be assessed by tracking components during time-lapse live cell imaging, demonstrating physical interactions, and visualizing interactions within cells by fluorescence resonance energy transfer (FRET). PI(4,5)P2 levels in pathway mutants will be directly correlated with PKC- MAPK cell wall integrity pathway activation. The third aim is to link transcription factors to the PI(4,5)P2-septin pathway, and identify transcriptional outputs and pathway targets that contribute to caspofungin responses and pathogenesis. Transcriptional outputs will be defined during intra-abdominal candidiasis of mice by using RNA-Seq, a largely unbiased method that comprehensively quantitates gene expression. The project employs a series of innovative techniques to study a novel pathway that is relevant to antifungal drug resistance and the pathogenesis of candidiasis. Therefore, it is likely to yield clinically useful insights that would not be obtained through other studies. Our findings will be significant because they will explain how the PI(4,5)P2-septin pathway governs cell wall integrity, echinocandin susceptibility and resistance, and pathogenesis, and place the pathway within the context of other regulators of these processes. The project will open new avenues of investigation that will define, in detail, the molecular and cellular mechanisms by which the PI(4,5)P2-septin pathway contributes to diverse types of candidiasis, and the impact of cell wall regulation on interactions with the host.

血吸虫病是美国第四大常见的血液感染，和其他形式的系统性 念珠菌病与40%或更高的死亡率相关，尽管用抗真菌剂治疗。的 白念珠菌细胞壁是念珠菌病发病机制的核心，但连接细胞壁的机制 调控和毒性才刚刚开始被理解。最近，我们证明了C。白色 迅速离域磷脂酰肌醇-（4，5）-二磷酸（PI（4，5）P2）和septins作为天然的一部分， 对细胞壁活性抗真菌剂卡泊芬净的反应。此外，我们还鉴定了一个新的C.白色 PI（4，5）P2-septin途径调节念珠菌病小鼠细胞壁完整性和毒力。我们 假设激活或下调PI（4，5）P2-septin通路的能力，如由细胞因子所决定的， 环境（即，平衡调节）对于最佳C是必要的。白念珠菌对细胞壁应力的反应 药物暴露或侵袭性念珠菌病。这个项目的目标是证明我们的平衡监管 假设，验证提出的PI（4，5）P2-septin途径，并鉴定其输出。我们将追捕三名 具体目标。第一个目的是证明平衡的PI（4，5）P2调节与保护性细胞凋亡相关。 对卡泊芬净的反应。动态PI（4，5）P2响应将与PI（4，5）P2-细胞中的细胞活力相关。 调节突变体和卡泊芬净敏感和耐药C.白色念珠菌菌株。第二个目标是 建立卡泊芬净给药期间PI（4，5）P2和其他PI（4，5）P2-septin途径组分之间的相互作用 暴露和侵袭性念珠菌病。将通过在延时期间跟踪组件来评估相互作用 活细胞成像，演示物理相互作用，并通过荧光可视化细胞内的相互作用 共振能量转移（FRET）。途径突变体中的PI（4，5）P2水平将与PKC直接相关。 MAPK细胞壁完整性通路激活。第三个目的是将转录因子连接到PI（4，5）P2-septin 途径，并鉴定有助于卡泊芬净应答的转录产物和途径靶标， 发病机制在小鼠腹腔内念珠菌感染期间，将通过使用 RNA-Seq是一种基本上无偏的方法，可全面定量基因表达。 该项目采用一系列创新技术来研究与抗真菌药物相关的新途径， 耐药性和念珠菌病的发病机制。因此，它可能会产生临床上有用的见解， 这是其他研究所无法获得的。我们的发现将是重要的，因为它们将解释如何 PI（4，5）P2-septin途径控制细胞壁完整性、棘白菌素敏感性和抗性， 发病机制，并将这些过程的其他调节剂的背景下的途径。该项目将 开辟了新的研究途径，将详细定义分子和细胞机制， PI（4，5）P2-septin途径导致不同类型的念珠菌病，细胞壁调节的影响 与宿主的互动。