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

基本信息

批准号：
8897263
负责人：
Hugues Ouellet
金额：
$ 36.48万
依托单位：
UNIVERSITY OF TEXAS EL PASO
依托单位国家：
美国
项目类别：
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/8897263
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 Extreme drug resistant tuberculosis 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 in vivo killings knockout gene macrophage metabolomics mutant new therapeutic target oxidation pathogen reconstitution resistant strain

项目摘要

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) 是结核病的病原体，每年导致 200 万人死亡，并潜伏感染三分之一的人世界人口的比例。近年来，由于多种耐药菌株的扩散和广泛耐药菌株的出现，结核病的威胁有所增加。结核分枝杆菌是一种细胞内病原体，它已进化出克服感染过程中遇到的环境变化（例如低氧气、一氧化氮和可用营养物质）的机制。这些适应机制的详细生化特征以及更好地了解它们在感染过程中的作用是开发新的有效抗结核药物的基本要求。例如，结核分枝杆菌具有分解代谢宿主胆固醇作为碳和能量来源的不同寻常的能力，并且这种能力已被证明是在动物模型中持久存在所必需的。然而，胆固醇分解代谢活动，包括β-氧化反应和胆固醇脂肪侧链的降解，尚未完全了解。我们和其他人表明，胆固醇侧链的降解导致结核分枝杆菌脂质组的变化，包括脂质毒力因子硫代甘油二霉菌酯的质量增加。我们还报道了两种 Mtb 甾醇 C26-单加氧酶 CYP125 和 CYP142 在引发胆固醇侧链降解中的作用，并证明这种活性对于 Mtb 在胆固醇上生长作为碳和能量的来源至关重要。用于 cholest-4-en-3-one 的解毒。基于这些观察，我们假设感染期间胆固醇侧链的分解代谢重塑了结核分枝杆菌的代谢，作为细胞内生存的适应性机制。为了检验我们的假设，在具体目标 1 中，我们将使用 Mtb 敲除菌株来鉴定降解胆固醇侧链的必需和多余的酶活性。在具体目标 2 中，将进行代谢组学分析和酶分析，以确定胆固醇侧链降解酶的生理底物。在具体目标 3 中，我们将使用诱导型蛋白质敲低方法来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。拟议的研究将扩展目前对结核分枝杆菌长期生存适应机制的了解，并将有助于验证新的药物靶点。