Translational Regulation of Candida glabrata Azole Resistance

项目总结/摘要 光滑念珠菌是一种重要的人类真菌病原体，能够引起全身和粘膜 各种免疫功能低下个体的感染，包括器官移植受者、癌症 化疗患者和艾滋病患者。C.光滑念珠菌是第二常见的分离念珠菌 在侵袭性血流感染中，有很高的粗死亡率（~40 - 60%），并已被分类为 疾病控制中心（CDC）将其列为对公共健康的“严重”威胁。而C.光滑 临床分离株对多种抗真菌药物，特别是唑类药物的敏感性呈上升趋势， 可用于治疗。以往的研究表明，C.光滑的抗真菌药耐药性可归因于 各种基因点突变，染色体重排以及某些转录的增加， 药物外排泵与遗传和转录机制相反， 控制C. glabrata或其它人类真菌病原体。 然而，我们和其他人已经表明，长5 'UTR介导的翻译效率机制在转录过程中起着重要作用。 在控制念珠菌毒力相关过程的几个关键调节因子的表达中起重要作用 白色念珠菌，并且基于RNA-seq数据，许多C.特异性参与唑类耐药的glabrata基因也 具有可能参与翻译调控的长5 'UTR。使用全基因组核糖体分析， 我们最近证明了C.白色念珠菌酵母丝转变是在广泛的翻译 对照和几个与抗真菌药物抗性相关的基因也显示了改变的翻译效率 在这个过渡时期。在酿酒酵母中进行类似的核糖体分析， 与C. glabrata，也显示了显着的翻译表达变化，在氧化应激反应。 许多C。对蛋白质合成重要的glabrata基因在唑类药物作用下显著下调 治疗此外，C. glabrata基因在唑类中显示改变的蛋白质表达 抗性与敏感分离株也显示了转录水平的变化，证据表明C. glabrata ERG 11编码唑靶羊毛甾醇14 β-脱甲基酶，可能处于翻译控制之下。 基于这些观察，我们假设翻译机制在 控制C.光滑的为了验证这一假设，我们将：1）确定基因组- C. glabrata对氟康唑治疗的反应，最常用的 唑类药物，2）识别和表征驱动C.光滑唑 阻力最终，这项研究将提供更好地了解全球监管电路和途径 控制C。glabrata azole耐药在翻译水平。此外，这项研究将确定和 描述了几个关键的调节因子对C. glabrata耐药性， 潜在地作为新的抗真菌策略的发展的目标。

PROJECT SUMMARY/ABSTRACT Candida glabrata is an important human fungal pathogen capable of causing both systemic and mucosal infections in a wide variety of immunocompromised individuals, including organ transplant recipients, cancer patients on chemotherapy and AIDS patients. C. glabrata is the second most frequently isolated Candida species in invasive bloodstream infections, has a high crude mortality rate (~40-60%), and has been classified as a “serious” threat to public health by the Centers for Disease Control (CDC). While resistance of C. glabrata clinical isolates to multiple antifungals, particularly azoles, is on the rise only three major drug classes are available for treatment. Previous studies have shown that C. glabrata antifungal resistance can be attributed to a variety of genetic point mutations, chromosomal rearrangements as well as increased transcription of certain drug efflux pumps. In contrast to genetic and transcriptional mechanisms, very little is known about translational mechanisms that control antifungal resistance in C. glabrata or other human fungal pathogens. However, we and others have shown that long 5’ UTR-mediated translational efficiency mechanisms play an important role in controlling the expression of several key regulators of virulence-related processes in Candida albicans and, based on RNA-seq data, many C. glabrata genes specifically involved in azole resistance also possess long 5’ UTRs that could be involved in translational regulation. Using genome-wide ribosome profiling, we have recently demonstrated that the C. albicans yeast-filament transition is under widespread translational control and several genes associated with antifungal resistance also showed altered translational efficiency during this transition. A similar ribosome profiling analysis in Saccharomyces cerevisiae, which is more closely related to C. glabrata, also showed significant translational expression changes in response to oxidative stress. Many C. glabrata genes important for protein synthesis are significantly down-regulated in response to azole treatment. In addition, only a small fraction of C. glabrata genes showing altered protein expression in azole resistant vs. susceptible isolates also showed changes at the transcript level and evidence suggests that C. glabrata ERG11, encoding the azole target lanosterol 14-demethylase, could be under translational control. Based on these observations, we hypothesize that translational mechanisms play an important role in controlling azole resistance in C. glabrata. In order to test this hypothesis, we will: 1) determine the genome- wide translational profile of C. glabrata in response to treatment with fluconazole, the most commonly used azole drug, 2) identify and characterize translational mechanisms important for driving C. glabrata azole resistance. Ultimately, this study will provide a better understanding of global regulatory circuits and pathways that control C. glabrata azole resistance at the translational level. In addition, this study will identify and characterize several key translationally regulated factors important for C. glabrata drug resistance that could potentially serve as targets for the development of novel antifungal strategies.