Mediator regulation of transporters in fluconazole resistant C. albicans mutants

氟康唑耐药白色念珠菌突变体转运蛋白的介导调节

• 批准号: 8850812
• 负责人: Lawrence Christopher Myers
• 金额: $ 20.25万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8850812
• 关键词: AIDS/HIV problem; Affect; Antibiotic Resistance; Antifungal Agents; Antimicrobial Resistance; Antineoplastic Agents; Azole resistance; Azoles; CDR1 gene; Candida albicans; Cells; Centers for Disease Control and Prevention (U.S.); Cessation of life; Chemosensitization; Chronic Disease; Clinical; Complex; DNA Binding; Data; Dependence; Disease; Disease model; Disseminated candidiasis; Drug Efflux; Drug resistance; Exposure to; Factor X; Family; Fluconazole; Fluconazole resistance; Fungal Drug Resistance; Gene Targeting; Genes; Genetic Transcription; HIV; Health; Highly Active Antiretroviral Therapy; Hospitals; Human; Individual; Infection Control; Lead; Life; Mediator of activation protein; Methods; Modeling; Molecular; Morbidity - disease rate; Multi-Drug Resistance; Multidrug Resistance Gene; Mutation; Organism; Patients; Pharmaceutical Preparations; Proteins; Qualifying; Recruitment Activity; Regulation; Reporting; Research; Resistance; Running; Saccharomyces cerevisiae; Sepsis; Tail; Testing; Therapeutic; Toxin; Transcriptional Activation; Transcriptional Activation Domain; Transcriptional Regulation; United States; Up-Regulation; Xenobiotics; Yeasts; Zinc Cluster; base; burden of illness; design; efflux pump; fungus; gain of function; gain of function mutation; immunosuppressed; in vivo Model; meetings; member; mortality; multi drug transporter; mutant; oropharyngeal thrush; pathogen; resistance mechanism; response; success; transcription factor

DESCRIPTION (provided by applicant): C. albicans is the most prevalent human fungal pathogen and is a leading cause of hospital-acquired bloodstream infections. There is an approximately 40% mortality rate, and over 10,000 deaths per year in the U.S. associated with systemic candidiasis. Azole drugs have met with some success in controlling these infections. However, a recently released Center for Disease Control report 'Antibiotic resistance threats in the United States, 2013' prioritized azole resistant C. albicans as a 'serious' threat to human health in the U.S. In addition, azole resistance runs especially high in HIV/AIDS patients suffering from oropharyngeal candidiasis in the developing world that lack access to highly active antiretroviral therapy, resulting in high morbidity and mortality. Understanding the molecular basis of azole (and other anti-fungals) resistance is critical to reducing disease burden. Clinical isolates of azole resistant C. albicans, and other fungal pathogens, frequently contain gain of function mutations in zinc cluster transcription factors that result in increased transcription of multi-drug efflux pumps. Little, however, is known about the mechanism used by these hyperactive transcription factors to activate their targets. Mediator is a highly conserved co-activator complex that is necessary for transcriptional regulation of most eukaryotic genes. Individual subunits within Mediator can be divergent and regulate specific subsets of genes within particular organisms. We hypothesize that gain of function mutations in zinc cluster transcription factors confer specific interactions with certain subunits of Mediator, which promote transcriptional activation of multi-drug efflux pump genes and anti-fungal resistance. The objective of this exploratory proposal is to specifically determine how Mediator facilitates fluconazole resistance conferred by gain of function mutations in Tac1, a C. albicans zinc cluster transcription factor that regulates the transporters Cdr1 and Cdr2. Moreover, we will compare the mechanisms used by different Tac1 gain of function mutants in order to determine whether there is a common interaction that could be therapeutically targeted. Preliminary evidence suggests this mechanism could be dependent on Mediator subunits specific to fungi, further supporting the feasibility of such a therapeutic approach.

描述（由申请人提供）：C。白色念珠菌是最普遍的人类真菌病原体，并且是医院获得性血流感染的主要原因。有大约40%的死亡率，并且在美国每年有超过10，000例死亡与系统性念珠菌病相关。唑类药物在控制这些感染方面取得了一些成功。然而，最近发布的疾病控制中心报告“2013年美国抗生素耐药性威胁”优先考虑唑类耐药C。此外，唑类耐药性在发展中国家患有口咽念珠菌病的HIV/AIDS患者中尤其高，这些患者缺乏获得高活性抗逆转录病毒治疗的途径，导致高发病率和死亡率。了解唑类（和其他抗真菌药物）耐药性的分子基础对于减少疾病负担至关重要。临床分离的唑类耐药念珠菌。白色念珠菌和其它真菌病原体经常在锌簇转录因子中含有功能获得突变，其导致多药物外排泵的转录增加。然而，人们对这些过度活跃的转录因子激活其靶点的机制知之甚少。介体是一种高度保守的辅激活因子复合物，是大多数真核基因转录调控所必需的。介体中的单个亚基可以是不同的，并调节特定生物体中的特定基因子集。我们假设锌簇转录因子的功能获得突变赋予了与介体的某些亚基的特异性相互作用， 多药外排泵基因的转录激活和抗真菌抗性。该探索性建议的目的是明确Mediator如何促进由Tac 1（C.调节转运蛋白Cdr 1和Cdr 2的白色念珠菌锌簇转录因子。此外，我们将比较不同的Tac 1获得功能突变体所使用的机制，以确定是否有一个共同的相互作用，可以治疗靶向。初步证据表明，这种机制可能依赖于真菌特异性介体亚基，进一步支持这种治疗方法的可行性。