MOLECULAR TARGETS OF AROMATIC DICATIONIC DRUGS IN FUNGI

真菌中芳香族双阳离子药物的分子靶标

基本信息

批准号：
5205555
负责人：
JOHN R PERFECT
金额：
--
依托单位：
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

项目摘要

Cryptococcus neoformans causes a life-threatening human mycoses in severely immunocompromised hosts such as transplant, cancer, and AIDS patients. Despite amphotericin B and newer triazoles for treatment, the management of this infection remains problematic. It is our belief that the discovery of new antifungal drugs coupled with the elicitation of the basic molecular mechanisms by which these drugs act are of prime importance. Over the past few years the molecular biology of C. neoformans has significantly expanded. Effective transformation systems have been developed for C. neoformans and recently in our laboratory gene-knockouts and plasmid rescue procedures have been accomplished using the biolistic DNA delivery system. An animal model of cryptococcal meningitis has been established which closely duplicates the human infection in the central nervous system and has been used both for molecular studies of virulence and treatment evaluations. With this molecular background and the biochemical support of the drug discovery group, we propose to identify and characterize both susceptibility and resistance of C. neoformans to aromatic dicationic compounds at the molecular level. We have found potent fungicidal activity in vitro with some of these compounds and presently we are screening classes of these compounds with the biochemists within the group to identify particular structure-function relationships. Initial molecular studies will focus on topoisomerase I and II of C. neoformans since recent studies indicate that they may be the targets of some dicationic agents. It is probable, however, that some of the new dicationic agents or their derivatives which have potent fungicidal activities in vitro use other molecular targets. Therefore, generation of drug-resistant mutants and restoration of drug susceptibility by gene complementation will be used to determine if there are other molecular targets of these compounds which have high affinity for DNA. It is probable that isolation of genes which restore susceptibility will identify some genes which determine the entrance and/or interaction of the drug with the target molecule. These genes or their deduced proteins will give further structure-function relationships to design selective agents. We expect that by understanding the molecular targets of these drugs through their interaction with C. neoformans DNA we will open up new avenues and chemical designs for our biochemists that may be applicable to other pathogenic fungi. It is of prime importance that antifungal drugs should have as wide spectrum as possible but with low host toxicity. The use of molecular biology for the study of drug targets coupled with the biochemistry of those targeted genes should allow for custom tailoring new drugs in this class.

加密的新外形导致威胁生命的人真菌严重免疫功能低下的宿主，例如移植，癌症和艾滋病患者。尽管有两性霉素B和较新的治疗三唑，但这种感染的管理仍然有问题。我们的信念是发现新的抗真菌药物的发现以及引起这些药物作用为主要的基本分子机制重要性。在过去的几年中大大扩展。有效的转换系统已经为Neoformans和最近的实验室基因敲除开发和质粒救援程序是使用生物学完成的 DNA输送系统。一个隐球菌脑膜炎的动物模型已经建立了密切复制中央人类感染的神经系统，两者都被用于毒力的分子研究和治疗评估。具有这种分子背景和药物的生化支持发现小组，我们建议识别和表征两者 Neoformans对芳香族性疾病的敏感性和耐药性分子水平的化合物。我们发现有效的杀真菌活动在体外与其中一些化合物，目前我们正在筛选这些化合物与小组中的生物化学家的类别确定特定的结构功能关系。初始分子自最近研究表明，它们可能是某些疾病剂的靶标。但是，很可能有一些新的dication剂或其在体外具有有效的杀真菌活动的衍生物使用其他分子靶标。因此，产生耐药突变体和通过基因互补恢复药物易感性将用于确定这些化合物是否还有其他分子靶标对DNA具有高亲和力。基因的隔离很可能恢复易感性将识别一些决定的基因药物与靶分子的入口和/或相互作用。这些基因或其推导的蛋白质将提供进一步的结构功能设计选择性代理的关系。我们希望通过理解这些药物通过与C的相互作用的分子靶标的。 Neoformans DNA我们将为我们的新途径和化学设计开放可能适用于其他致病真菌的生物化学家。它是最重要的是，抗真菌药物应具有与可能，但宿主毒性低。分子生物学用于对靶向人的生物化学结合的药物靶标的研究基因应允许在此类中定制调整新药。