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：
7911623
负责人：
Brendan Cormack
金额：
$ 20.5万
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 2012-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7911623
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）：光滑念珠菌是 HIV 血清阳性和 HIV 血清阴性人群中重要的机会病原体。在美国，过去15年的大多数临床系列显示，光滑念珠菌占粘膜和播散性念珠菌病的15-20%，光滑念珠菌对三唑类抗真菌药物具有天然耐药性，因此需要开发新的化疗药物治疗光滑念珠菌播散性和粘膜感染的策略。柠檬酸甲酯循环代表了光滑念珠菌治疗干预的极好潜在靶点。柠檬酸甲酯循环对丙酸和丙酰辅酶A进行解毒，丙酸和丙酰辅酶A是光滑念珠菌内源产生的蛋白质降解的副产物。该循环在 Cit3、Pdh1 和 Icl2 酶的催化下分三个步骤将丙酸降解为丙酮酸。我们已经表明，整个甲基柠檬酸循环在巨噬细胞的吞噬作用后被强烈诱导。我们还表明，PDH1 或 ICL2 的破坏使光滑念珠菌对丙酸盐极其敏感，这可能是由于代谢毒素柠檬酸甲酯的积累所致。我们建议首先分析如何控制柠檬酸甲酯循环的通量；具体来说，我们想知道在光滑念珠菌中，丙酸如何转化为丙酰辅酶A，这是甲基柠檬酸循环的入口点。我们假设这种活性是由于 ACS1 和/或 ACS2 基因编码的双功能乙酰辅酶 A 合成酶和丙酰辅酶 A 合成酶所致。我们将测试这一假设并确定 Acs 活性是否控制通过该途径的通量并增强丙酸盐毒性。我们还设计了全细胞测定法来筛选抑制 Pdh1 或 Icl2 的化合物。我们建议从 NCI DTP 化合物集合中筛选针对这些酶中任一酶的化合物。我们将以多种方式描述最初的点击。首先，我们将在体外确定这些化合物是否抑制 Pdh1 或 Icl2 活性；其次，我们将针对白色念珠菌或烟曲霉的直系同源酶测试阳性化合物，以评估针对其他重要真菌病原体的活性。这是一个高风险的项目，也是我实验室的一个新的研究领域；抑制该循环的化合物的鉴定将在未来允许在播散性和粘膜感染模型中的感染过程中表征柠檬酸甲酯循环。活性化合物也可能为人类疗法的未来发展提供一个起点。公共卫生相关性：光滑念珠菌是 HIV 阳性和 HIV 阴性个体感染的重要原因。我们正在研究光滑念珠菌中的柠檬酸甲酯循环，将其作为新药的潜在靶点。我们建议筛选 NIH 提供的大量化合物，以确定抑制该途径的化合物；其中一些可能最终导致念珠菌和其他真菌感染新疗法的开发。