AIDS Opportunistic Pathogens: Targeting the Methyl Citrate Cycle

艾滋病机会病原体：针对柠檬酸甲酯循环

基本信息

批准号：
7620189
负责人：
Brendan Cormack
金额：
$ 22.74万
依托单位：
JOHNS HOPKINS UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-08-11 至 2011-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7620189
关键词：
Accounting Acetyl Coenzyme A Acquired Immunodeficiency Syndrome Affect Animals Antifungal Agents Area Biochemical Biological Assay Branched-Chain Amino Acids Candida Candida albicans Candida glabrata Carbon Cell Wall Cells Citrates Clinical Collection Data Development Disseminated candidiasis Drug Metabolic Detoxication Environment Enzymes Exposure to Fatty Acids Future Genes Genetic HIV HIV Seropositivity Human Human Development In Vitro Individual Infection Investigation Lead Ligase Membrane Metabolic Metabolism Modeling Mycoses Nitrogen Pathway interactions Patients Phagocytosis Pharmaceutical Preparations Population Propionates Proteins Pyruvate Pyruvates Reaction Recombinants Resistance Role Screening procedure Series Source Testing Therapeutic Therapeutic Intervention Toxic effect Toxin Triazoles United States United States National Institutes of Health Virulence Yeasts base design high risk inhibitor/antagonist interest macrophage metabolic poison mutant novel oxidation pathogen propionyl-coenzyme A protein degradation public health relevance small molecule therapeutic target treatment strategy

项目摘要

DESCRIPTION (provided by applicant): Candida glabrata is an important opportunistic pathogen in HIV seropositive and HIV seronegative populations. In the United States, most clinical series over the last 15 years show that C. glabrata accounts for 15-20% of mucosal and disseminated candidiasis, C. glabrata is innately resistant to triazole antifungals, and there is a need for development of new chemotherapeutic strategies for treatment of C. glabrata disseminated and mucosal infections. The methylcitrate cycle represents an excellent potential target for therapeutic intervention in C. glabrata. The methylcitrate cycle carried out detoxification of propionate and propionyl-CoA, produced endogenously by C. glabrata as a byproduct of the degradation of protein. The cycle degrades propionate to pyruvate in three steps, catalyzed by the Cit3, Pdh1 and Icl2 enzymes. We have shown that the entire methylcitrate cycle is strongly induced following phagocytosis by macrophages. We have also shown that disruption of PDH1 or ICL2 renders C. glabrata exquisitely sensitive to propionate, likely due to the accumulation of the metabolic toxin methylcitrate. We propose first to analyze how flux through the methylcitrate cycle is controlled; specifically we would like to know how, in C. glabrata, propionate is converted to propionyl-CoA, the entry point into the methylcitrate cycle. We hypothesize that this activity is due to dual function acetyl- and propionyl-CoA synthetases encoded by the ACS1 and/or ACS2 genes. We will test this hypothesis and determine if Acs activity controls flux through the pathway and potentiates propionate toxicity. We also have designed a whole cell assay to screen for compounds that inhibit Pdh1 or Icl2. We propose to screen the NCI DTP compound collection for compounds that target either of these enzymes. We will characterize initial hits in several ways. First, we will determine in vitro if the compounds inhibit Pdh1 or Icl2 activity; second we will test positive compounds against the orthologous enzymes of C. albicans or A. fumigatus to assess activity against other important fungal pathogens. This is a high risk project, and a new area of investigation for my lab; identification of compounds that inhibit this cycle will in the future allow characterization of the methylcitrate cycle during infection in both disseminated and mucosal models of infection. Active compounds may also provide a starting point for future development of human therapeutics. PUBLIC HEALTH RELEVANCE: Candida glabrata is an important cause of infection in HIV-positive and HIV-negative individuals. We are studying the methylcitrate cycle in C. glabrata as a potential target for new drugs. We propose screening a large collection of compounds available from the NIH to identify compounds that inhibit this pathway; some of these may ultimately lead to development of new treatments of Candida and other fungal infections.

描述（由申请人提供）：念珠菌是HIV血清阳性和HIV血清神经种群中重要的机会性病原体。在美国，过去15年中的大多数临床系列都表明，C. glabrata占粘膜和散布的念珠菌病的15-20％，C。glabrata天生对三唑抗真菌性具有抗药性，并且需要开发新的化学治疗策略来治疗C. glabrata散发散发性抗体和粘膜含量。甲基c酸周期代表了在glabrata中进行治疗干预的绝佳潜在靶标。甲基c酸周期对丙酸和丙酰辅酶A进行了排毒，该甲基丙酸和丙酰辅酶A内源性产生，作为蛋白质降解的副产品。该循环以三个步骤丙旋丙酸酯降解，并由CIT3，PDH1和ICL2酶催化。我们已经表明，在巨噬细胞吞噬作用后，整个甲基c酸周期被强烈诱导。我们还表明，PDH1或ICL2的破坏使C. glabrata对丙酸酯非常敏感，这可能是由于代谢毒素甲基胆料的积累。我们首先建议分析如何控制通过甲基甲虫周期的通量。具体而言，我们想知道，在丙酸梭状芽胞杆菌中，丙酸酯如何转化为丙酰辅酶A，即进入甲基co酸盐循环。我们假设该活性是由于ACS1和/或ACS2基因编码的双重功能乙酰基和丙酰-COA合成酶。我们将检验该假设，并确定ACS活性是否控制通道的通量，并增强丙酸毒性。我们还设计了一个全细胞测定法，以筛选抑制PDH1或ICL2的化合物。我们建议将NCI DTP化合物集合筛选为靶向这些酶之一的化合物。我们将以几种方式表征初始命中。首先，我们将在体外确定化合物是否抑制PDH1或ICL2活性；其次，我们将测试针对白色念珠菌或烟曲霉的直系同源酶的阳性化合物，以评估针对其他重要的真菌病原体的活性。这是一个高风险项目，也是我的实验室的新调查领域；鉴定抑制此周期的化合物将来将允许在传播感染模型和粘膜模型中感染期间甲基c酸周期的表征。活性化合物也可能为未来人类治疗剂的发展提供了一个起点。公共卫生相关性：念珠菌是艾滋病毒阳性和艾滋病毒阴性个体感染的重要原因。我们正在研究glabrata中的甲基凝血周期，是新药的潜在靶标。我们建议筛选来自NIH可用的大量化合物，以识别抑制该途径的化合物。其中一些最终可能导致开发念珠菌和其他真菌感染的新疗法。