AIDS: Combatting drug resistance of Candida albicans

描述(申请人提供)：白色念珠菌是一种致病酵母菌，在免疫功能低下的人中会导致严重的真菌感染，而对抗性念珠菌感染可能是HIV+患者免疫抑制的第一个迹象。艾滋病患者经常患有口咽念珠菌病(OPC)，需要进行抗真菌治疗。在20世纪90年代，由于白色念珠菌菌株对氟康唑产生耐药性，导致艾滋病患者治疗OPC失败的氟康唑急剧增加。在这些酵母菌中，导致高水平氟康唑耐药的最常见机制是药物外排泵Cdrl p的过度表达。在全球范围内，OFC仍然是HIVIAIDS的主要对手感染，而氟康唑在第三世界的广泛使用可能会维持对白色念珠菌的压力，使其产生耐药性。这项研究的总体目标是使用一种新的策略来通过对抗白色念珠菌的氮耐药来改善患有口腔念珠菌病的艾滋病患者的治疗。具体目标是： 1.采用一种新的异源功能高效表达系统，利用体外诱变的Cdrl p蛋白和来自临床分离株(从艾滋病患者获得的)表现出高和低泵活性的Cdrl p蛋白来确定Cdrl p的泵送机制。 2.利用Cdrlp的异源功能超表达筛选出一个独特的抑制泵的多肽的组合文库。 这项工作将验证一种对抗白念珠菌耐药的新方法。对药物泵机制的了解可能会为规避外排介导的耐药性提供新的途径。该项目预计将确定一种可能使耐药菌株对唑类抗真菌药物敏感的先导化合物。

DESCRIPTION (provided by applicant): Candida albicans is a pathogenic yeast that causes serious fungal infections in the immunocompromised and opponunistic Candida infections can be the first indication of immunosuppression in HIV+ individuals. AIDS patients frequently suffer from oropharyngeal candidiasis (OPC) and require antifungal therapy. In the 1990s there was a dramatic increase in the failure of fluconazole therapy for AIDS patients with OPC due to C. albicans strains developing fluconazole resistance. The most common mechanism responsible for high level fluconazole resistance in these yeast was over-expression of drug efflux pump Cdrl p. Globally, OFC remains a major opponunistic infection in HIVIAIDS, and the widespread use of fluconazole in the third world is likely to maintain pressure on C. albicans to develop resistance. The overall objective of this research is to use a novel strategy to improve the treatment of AIDS patients with oral candidiasis by combating azoleresistance in C. albicans. Specific objectives are to: 1. Employ a novel heterologous functional hyper-expression system to determine the mechanism of pumping by Cdrl p, using both in vitro mutagenized Cdrl p and Cdrl proteins from clinical C. albicans isolates (obtained from AIDS patients) that demonstrate high and low pump activities. 2. Use the heterologous functional hyper-expression of Cdrlp to screen a unique combinatorial Doctapeptide library for peptides that inhibit the pump. This work will validate a novel approach to combating azole-resistance in C. albicana An understanding of drug pumping mechanisms may indicate new ways to circumvent efflux-mediated resistance. This project is expected to identify a lead compound with the potential to sensitize resistant strains to azole antifungals.