Role of Cholesterol Metabolism in Pathogenesis of Mycobacterium Tuberculosis

胆固醇代谢在结核分枝杆菌发病机制中的作用

• 批准号: 9112855
• 负责人: Hugues Ouellet
• 金额: $ 33.98万
• 依托单位: UNIVERSITY OF TEXAS EL PASO
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9112855
• 关键词: Achievement; Acyl CoA Dehydrogenases; Acyl Coenzyme A; Address; Animal Model; Biochemical; Biochemical Pathway; Biological Assay; Bone Marrow; C57BL/6 Mouse; Carbon; Catabolism; Cells; Cessation of life; Cholesterol; Cholesterol Homeostasis; Chromosomes; Chronic; Data; Defect; Degradation Pathway; Development; Drug Metabolic Detoxication; Drug Targeting; Environment; Enzymes; Genes; Goals; Growth; Health; Human; In Vitro; Incubated; Infection; Knock-out; Knowledge; Length; Ligase; Lipids; Mass Spectrum Analysis; Metabolic Pathway; Metabolism; Mixed Function Oxygenases; Modeling; Molecular; Multi-Drug Resistance; Mus; Mycobacterium bovis; Mycobacterium smegmatis; Mycobacterium tuberculosis; Nutrient; Pathogenesis; Pathogenicity; Pathway interactions; Pharmaceutical Preparations; Physiological; Play; Population; Proteins; Publishing; Reaction; Recombinant Proteins; Recombinants; Reporting; Research; Resolution; Role; Side; Source; Sterols; System; Testing; Therapeutic; Therapeutic Agents; Therapeutic Intervention; Tuberculosis; Validation; Virulence; Virulence Factors; acyl-CoA dehydrogenase; aerosolized; base; cholest-4-en-3-one; environmental change; enzyme substrate; extensive drug resistance; in vivo; killings; knock-down; knockout gene; macrophage; metabolomics; mutant; new therapeutic target; oxidation; pathogen; reconstitution; resistant strain

DESCRIPTION (provided by applicant): Mycobacterium tuberculosis (Mtb), the etiological agent of tuberculosis, is responsible for two million deaths annually, and latently infects a third of the world's population. The threat of TB has increased in recent years because of the proliferation of multiple drug-resistant strains and the emergence of extensively drug-resistant strains. Mtb is an intracellular pathogen that has evolved mechanisms to overcome environmental changes (e.g. low O2, NO, and available nutrients) encountered during infection. A detailed biochemical characterization of these mechanisms of adaptation as well as a better understanding of their roles during infection are essential requirements for the development of new and effective anti-tubercular drugs. For instance, Mtb has the unusual ability to catabolize host cholesterol as a source of carbon and energy, and this capacity has been shown to be required for persistence in animal models. However, cholesterol catabolic activities, including the beta-oxidation reactions and the degradation of the aliphatic side-chain of cholesterol, are not fully understood. We and others showed that the degradation of the cholesterol side-chain led to changes in Mtb's lipidome, including an increased mass of the lipid virulence factor phthiocerol dimycocerosate. We also reported on the role of the two Mtb sterol C26-monooxygenases, CYP125 and CYP142, in the initiation of cholesterol side-chain degradation, and demonstrated that this activity was essential for growth of Mtb on cholesterol as a source of carbon and energy and for detoxification of cholest-4-en-3-one. Based on these observations, we hypothesize that the catabolism of the cholesterol side-chain during infection reshapes Mtb's metabolism as an adaptive mechanism to survive intracellularly. To test our hypothesis, in Specific Aim 1, we will identify essential and redundant enzymatic activities for the degradation of the cholesterol side-chain using Mtb knockout strains. In Specific Aim 2, metabolomic profiling and enzymatic assays will be conducted to identify the physiological substrate(s) of the cholesterol side-chain degrading enzymes. In Specific Aim 3, we will use an inducible protein knockdown approach to better define the role of cholesterol side-chain degrading enzymes in infectivity and persistence in vivo. The proposed study will extend the current knowledge of Mtb's mechanisms of adaptation for long-term survival and will help to validate new drug targets.

描述（由申请人提供）：结核分枝杆菌（MTB），结核病的病因学药，每年造成200万人死亡，并潜伏感染三分之一 世界人口。近年来，由于多种耐药菌株的扩散以及广泛的抗药性菌株的出现，结核病的威胁近年来有所增加。 MTB是一种细胞内病原体，具有克服环境变化的机制（例如，低O2，NO和可用营养素）。这些适应机制的详细生化表征以及对感染过程中其作用的更好理解是开发新的有效抗结核药物的必不可少的要求。例如，MTB具有将宿主胆固醇分解为碳和能量来源的异常能力，并且已证明这种能力在动物模型中持续存在必要。然而，尚不完全了解胆固醇的活性，包括β-氧化反应和脂肪族侧链的降解。我们和其他人表明，胆固醇侧链的降解导致MTB脂质组的变化，包括增加的脂质毒力因子苯二耐酚二氧甲磷酸酯的质量增加。我们还报道了两种MTB固醇C26-共氧酶CYP125和CYP142在胆固醇侧链降解中的作用，并证明这种活动对于胆固醇上MTB作为碳和能量的胆固醇和能量的来源以及对胆固醇的来源以及胆固醇的来源至关重要。基于这些观察结果，我们假设感染期间胆固醇侧链的分解代谢重塑了MTB代谢作为一种适应性机制，可在细胞内生存。为了检验我们的假设，在特定的目标1中，我们将使用MTB敲除菌株确定胆固醇侧链降解的必要和冗余酶活性。在特定的目标2中，将进行代谢组分析和酶促测定，以鉴定胆固醇侧链降解酶的生理底物。在特定的目标3中，我们将使用诱导蛋白敲低方法更好地定义胆固醇侧链降解酶在体内感染性和持久性中的作用。拟议的研究将扩展当前对MTB适应机制以实现长期生存的知识，并有助于验证新药物靶标。