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

基本信息

批准号：
7576131
负责人：
Theodore C. White
金额：
$ 22.68万
依托单位：
SEATTLE BIOMEDICAL RESEARCH INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-03-01 至 2011-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7576131
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

项目摘要

DESCRIPTION (provided by applicant): 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 application 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. PUBLIC HEALTH RELEVANCE 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.

描述（由申请人提供）：病原性酵母白色念珠菌（CA）是免疫受损的人和女性阴道感染的经常引起口腔和全身真菌感染的原因。念珠菌感染通常用硫唑药物治疗，并且在这些患者种群中经常出现硫代抗性。硫唑耐药性的主要机制包括增加的外排泵表达和麦角固醇生物合成中酶的改变。但是，在许多抗性临床分离株中尚未发现这些抗性机制。最近，在念珠菌生物膜中发现了第三种唑耐药的机制 - 在粘膜表面和植入的医疗设备上形成的细胞和细胞外材料的基质。这些生物膜中试唑的耐药性较高是由于（在细胞壁中的-1,3葡聚糖与硫唑药物结合的结合）。我们的假设是（-1,3葡聚糖的结合（1,3 glucan glucan glucan）在生物膜上不仅在生物膜上，而且在浮游生物中均可及时抗体。增加的抵抗力。总体目标是评估偶氮与（-1,3 glucan作为念珠菌中耐药性的组成部分）的贡献。具体来说，该提案研究了（-1,3葡萄糖结合会影响真菌细胞中的药物积累1。为了确定（-1,3葡萄糖结合对白色念珠菌中氟康唑积累的影响。真菌细胞积累的硫代唑积聚可能是多个竞争过程的结果，包括进口和外排（内部积累），可能是-1,3 glucan glucan（-1,3葡聚糖结合）。在改变细胞的葡聚糖含量的条件下，将评估细胞中的放射性标记的FLC积累。 2。评估（-1,1,3葡聚糖在临床分离株中的结合，药物敏感性改变。硫烷与（-1,3葡萄糖和（细胞中的-1,3葡萄糖水平）的结合将在耐药性临床分离株中进行评估，在抗性临床分离株中，尚无已知的耐药性机制未知的相互作用，可以鉴定出临床上的相互作用。 Azole药物是这些过程的全部特征，以及我们对药物/细胞相互作用的其他方面的理解，有助于改善诊断，治疗和预防真菌感染和抗药性。氟康唑和白色念珠菌，它将检验以下假设：真菌细胞壁充当海绵，吸收药物，从而使细胞在存在药物的情况下持续存在。