Glucan Binding to Azole Drugs: A Novel Resistance Mechanism in Candida albicans

葡聚糖与唑类药物的结合：白色念珠菌的新型耐药机制

• 批准号: 7837029
• 负责人: Theodore C. White
• 金额: $ 1万
• 依托单位: SEATTLE BIOMEDICAL RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7837029
• 关键词: Affect; Anabolism; Antifungal Agents; Area; Azole resistance; Azoles; Binding; Biochemical; Blood; Candida; Candida albicans; Catheters; Cell Communication; Cell Wall; Cells; Clinical; Collection; Cytoplasm; Dental Plaque; Dentures; Diagnosis; Drug resistance; Enzymes; Ergosterol; Exhibits; Extracellular Matrix; Fluconazole; Future; Genes; Glucans; Goals; Immune; Implant; Infection; Laboratories; Medical Device; Metabolism; Microbial Biofilms; Modification; Monitor; Monoclonal Antibodies; Mycoses; Oral; Oral cavity; Patients; Pharmaceutical Preparations; Porifera; Predisposition; Preparation; Prevention; Process; Production; Pump; Radiolabeled; Reporting; Research; Resistance; Resistance to infection; Sterol Biosynthesis Pathway; Sterols; Stream; Surface; Testing; Vagina; Woman; Yeasts; candida biofilm; cell preparation; clinically significant; drug testing; efflux pump; extracellular; human disease; novel; patient population; prevent; radiotracer; resistance mechanism

Project Summary The pathogenic yeast Candida albicans (Ca) is a frequent cause of oral and systemic fungal infections in immune-compromised people and of vaginal infections in women. Candida infections are usually treated with azole drugs, and azole resistance arises frequently in these patient populations. The major mechanisms of azole resistance include increased expression of efflux pumps and alterations in enzymes in ergosterol biosynthesis. However, these mechanisms of resistance have not been identified in many resistant clinical isolates. Recently, a third mechanism of azole resistance has been found in Candida biofilms - matrices of cells and extracellular material that forms on mucosal surfaces and implanted medical devices. The high levels of azole resistance in these biofilms is due to increased production of ??1,3 glucan in the cell wall that binds to azole drugs. Our Hypothesis is that ??1,3 glucan binding of azoles is a component of resistance not only in biofilms, but in planktonic clinically resistant isolates. Glucan binding of azoles to the cell wall would prevent the drug from reaching the cytoplasm, increasing resistance. The Overall Goal is to evaluate the contribution of azole binding to ??1,3 glucan as a component of drug resistance in Candida. Specifically, this proposal investigates how ??1,3 glucan binding affects drug accumulation in fungal cells, and it evaluates ??1,3 glucan binding in a collection of clinical isolates, including isolates with no known resistance mechanisms. The Specific Aims of this proposal are: 1. To determine the effect of ??1,3 glucan binding on fluconazole accumulation in Candida albicans. Azole accumulation by fungal cells is likely to be the result of several competing processes, including import and efflux (internal accumulation), and possibly ??1,3 glucan binding (external accumulation). Radiolabeled FLC accumulation in cells will be evaluated under conditions that alter the glucan content of the cells. 2. To assess ??1,3 glucan binding in clinical isolates with altered drug susceptibilities. Azole binding to ??1,3 glucans, and ??1,3 glucan levels in the cells will be assessed in resistant clinical isolates in which no known mechanism of resistance has been identified. The interactions between azoles and fungal cells will continue to be clinically significant issues for the foreseeable future. ??1,3 glucan binding of azole drugs is a new and important aspect of these interactions. A full characterization of this process, together with our understanding of the other facets of drug/cell interactions, has the potential to contribute to improvements in diagnosis, treatment and prevention of fungal infections and of resistance. Narrative The pathogenic yeast Candida albicans causes significant human disease in the mouth, vagina and blood stream. This proposal will analyze the interaction between the antifungal drug fluconazole and C. albicans. In particular, it will test the hypothesis that the fungal cell wall acts as a sponge, soaking up the drug, thus allowing the cells to persist in the presence of drug.

项目摘要 致病性酵母白色念珠菌（CA）是口服和全身真菌感染的常见原因 免疫受损的人和女性阴道感染。念珠菌感染通常治疗 这些患者种群中经常出现硫唑药物，并且抗唑的耐药性经常出现。专业 唑耐药的机制包括增加的外排泵表达和改变 麦角固醇生物合成中的酶。但是，尚未确定这些电阻机制 在许多抗性临床分离株中。最近，在 念珠菌生物膜 - 在粘膜表面形成的细胞和细胞外材料的矩阵 植入医疗设备。这些生物膜中高水平的唑耐药性是由于增加 在与硫唑药物结合的细胞壁中产生1,3葡聚糖。我们的假设是：1,3葡萄糖 试唑的结合不仅是生物膜中的抗性的组成部分，而且在浮游临床上具有抗性 分离物。叠唑与细胞壁的葡聚糖结合将阻止药物到达细胞质， 增加电阻。总体目标是评估唑的结合对?? 1,3 glucan的贡献 作为念珠菌中耐药性的组成部分。具体来说，该提案调查了如何？1,3葡聚糖 结合会影响真菌细胞中的药物积累，它评估了一个集合中的葡聚糖结合 临床分离株，包括没有已知抗性机制的分离株。这个特定的目的 提案是： 1。确定1.1 1,3葡聚糖结合对氟康唑在念珠菌中的积累的影响 白色唱片。真菌细胞积累的唑可能是几个竞争过程的结果， 包括进口和外排（内部积累），以及可能的1,3葡聚糖结合（外部 积累）。在改变的条件下，将评估放射性标记的FLC在细胞中的积累 细胞的葡萄糖含量。 2。评估临床分离株中具有改变药物敏感性的glucan结合。 azole 将在耐药性临床中评估与1,3葡萄糖的结合，并且细胞中的1,3葡萄糖水平将进行评估 尚未鉴定出已知抗性机制的分离株。 偶氮和真菌细胞之间的相互作用将继续是临床上重要的问题。 可预见的未来。 azole药物的1,3葡聚糖结合是这些新的重要方面 互动。这一过程的全面表征，以及我们对其他方面的理解 药物/细胞相互作用，有可能有助于改善诊断，治疗和 预防真菌感染和抗药性。叙述 病原性酵母白色念珠菌在口腔，阴道和 血流。该建议将分析抗真菌药物氟康唑和 白色念珠菌。特别是，它将检验以下假设，即真菌细胞壁充当海绵，浸泡 加强药物，从而使细胞在存在药物的情况下持续。