AIDS Related Oral Candidiasis: Drugs, Sterols, and Fungal Cells

致病性酵母菌白色念珠菌（Ca）是免疫系统真菌感染的主要原因， 包括艾滋病患者在内的弱势群体。通常用抗真菌药物治疗， 通常是唑类氟康唑，广泛用于艾滋病患者。在这些患者中， 唑类耐药性很有可能发展。使用艾滋病患者的口服耐药菌株， 已经确定了主要的耐药机制，包括ERG 11（一种编码 麦角固醇生物合成中的酶和唑类的靶点）和增加的外排泵表达。 麦角甾醇是真菌细胞膜上的主要甾醇，其生物合成是唑类化合物的靶标 和许多其他抗真菌药物 真菌细胞与唑类化合物的相互作用是一个复杂的过程。代谢的具体方面和 环境影响体外药物/细胞相互作用，并有可能在临床上发挥重要作用。的 本研究的总体目标是了解真菌细胞如何对唑类反应。这项建议 研究进口，随后的调节固醇的UPC 2转录因子，和影响 环境因素对细胞对药物反应的影响。该提案的具体目标是： 1.研究氟康唑进入真菌细胞的特性。唑类化合物的导入对细胞/药物很重要 相互作用;它可能通过被动或主动转运介导;以前没有研究过。 2.分析UPC 2的转录调控。一旦在细胞内，唑类抑制Erg 11 p， 改变固醇水平，激活UPC 2转录因子，调节固醇生物合成 和摄取。将分析UPC 2基因的调控，以了解固醇的变化 代谢，包括摄取和生物合成与UPC 2的表达相关。 3.描述特定环境因素对药物敏感性和细胞的影响 面环境因素，包括pH值、氧气水平、氮源和外源甾醇， 将分析它们对药物敏感性和细胞表面的影响，使用微生物， 生物化学和基因表达方法。 4.表征临床分离株的甾醇代谢改变。已知的机制 耐药性并不适用于许多耐药菌株。这一目标将分析输入，UPC 2调节， 对环境因素的反应，以确定这些菌株中可能的新的耐药机制。 理解唑类和真菌细胞之间的相互作用是临床上重要的问题， 提高诊断、治疗和预防真菌感染和耐药性的潜力。

The pathogenic yeast Candida albicans (Ca) is a major cause of fungal infections in immune- compromised populations including AIDS patients. It is usually treated with antifungal drugs, most commonly the azole fluconazole which is used extensively in AIDS patients. In these patients, there is a significant probability that azole resistance will develop. Using oral resistant isolates from AIDS patients, major mechanisms of resistance have been identified including alterations in ERG11 (a gene encoding an enzyme in ergosterol biosynthesis and target of the azoles) and increased expression of efflux pumps. Ergosterol is the major sterol in the fungal plasma membrane; and its biosynthesis is the target for azoles and many other antifungals The interaction of fungal cells with azoles is a complex process. Specific aspects of metabolism and the environment influence drug/cell interactions in vitro and have the potential to be important clinically. The Overall Goal of this research is to understand how a fungal cell responds to azoles. This proposal investigates import, subsequent regulation of sterols by the UPC2 transcription factor, and the influence of environmental factors on the cellular response to drugs. The Specific Aims of this proposal are: 1. To characterize fluconazole import into the fungal cell. Azole import is important to the cell/drug interaction; it may be mediated by passive or active transport; and it has not been studied previously. 2. To analyze the transcriptional regulation of UPC2. Once within the cell, azoles inhibit Erg 11 p, altering sterol levels, and activating the UPC2 transcription factor, which regulates sterol biosynthesis and uptake. Regulation of the UPC2 gene will be analyzed to understand how changes in sterol metabolism, including uptake and biosynthesis are correlated with expression of UPC2. 3. To characterize the effect of specific environmental factors on drug susceptibility and the cell surface. Environmental factors, including pH, oxygen levels, nitrogen sources, and exogenous sterols, will be analyzed for their effect on the drug susceptibility and the cell surface, using microbiological, biochemical and gene expression approaches. 4. To characterize clinical isolates for alterations in sterol metabolism. The known mechanisms of resistance do not apply to many resistant strains. This aim will assay import, UPC2 regulation, and response to environmental factors to identify possible new resistance mechanisms in these isolates. Understanding the interactions between azoles and fungal cells is a clinically significant issue, with the potential for improving diagnosis, treatment and prevention of fungal infections and resistance.