The role and fate of Mtb storage lipids LCTAG and MWE

Mtb 储存脂质 LCTAG 和 MWE 的作用和命运

• 批准号: 9893601
• 负责人: Georgiana E. Purdy
• 金额: $ 24.41万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-23 至 2022-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9893601
• 关键词: Anabolism; Antibiotic Resistance; Bacteria; Biochemical; Biological; Biological Process; Carbon; Cause of Death; Cell Wall; Communicable Diseases; Cytoplasm; Data; Disease; Drug Tolerance; Energy-Generating Resources; Environment; Esters; Exhibits; Failure; Fatty Acids; Genes; Genetic; Genus Mycobacterium; Granuloma; Homeostasis; Hypoxia; In Vitro; Lipids; Membrane; Metabolic; Metabolism; Microbial Biofilms; Modeling; Mycobacterium tuberculosis; Necrosis; Nutrient; Organism; Oxygen; Pathway interactions; Phase; Phenotype; Physiology; Proteins; Recycling; Research; Research Personnel; Resource Sharing; Resources; Resuscitation; Role; Source; Stress; Surface; System; Testing; Triglycerides; Tuberculosis; Up-Regulation; Virulence; Waxes; base; capsule; cell envelope; deprivation; esterase; experimental study; extracellular; human pathogen; in vitro Model; in vivo; latent infection; lipid transport; metabolomics; mutant; mycobacterial; mycolate; response; success; targeted treatment; transcriptome sequencing; tuberculosis drugs

SUMMARY Tuberculosis is one of the leading causes of death due to infectious disease despite the availability of anti- tubercular drugs. The majority of M. tuberculosis (Mtb) infections result in latent TB where bacteria have altered metabolism and exhibit phenotypic drug tolerance. The biological pathways used to maintain metabolic homeostasis and then fuel resuscitation and replication are poorly understood. A crucial component of dormancy or quiescence is the storage of carbon and energy sources in cell wall lipids that can be recycled upon resuscitation. Mtb generates the “storage lipids” triacylglycerol (TAG) and wax esters (WE) in late stationary phase and in response to stresses commonly associated with dormancy. During the transition to active replication, it is believed that these lipids are mobilized and employed as a metabolic resource. However, this has not been experimentally demonstrated. We recently described the Very Long- Chain triacylglycerol (LCTAG) and mycolate wax ester (MWE) of Mtb. These lipids are exported from the cytoplasm to the mycobacterial outer membrane or capsule by the MmpL11 transporter. The fates of LCTAG and MWE once they are extracellular are not known. However, correct localization of LCTAG and MWE is important for Mtb virulence and physiology since 1) MmpL11 is required for virulence and 2) the Mtb mmpL11 mutant has reduced resuscitation from an in vitro non-replicating persistence model. As storage lipids, surface- localized LCTAG and MWE may be utilized as a shared resource to maintain viability and resuscitate from non-replicating persistence. Based on our data, we hypothesize that Mtb hydrolyzes, imports and utilizes exported storage lipids to promote resuscitation from hypoxic and nutrient-restricted environments. We propose to test this hypothesis by 1) Determining how LCTAG and MWE contribute to Mtb resuscitation from non-replicating persistence, and 2) Define proteins involved in the LCTAG and MWE biosynthesis and recycling pathway. This exploratory study combines unbiased approaches with genetic and biochemical analyses to investigate the important biological process of Mtb cell envelope remodeling in metabolism.

概括 尽管有抗结核药物可用，但结核病仍是传染病导致死亡的主要原因之一。 大多数结核分枝杆菌 (Mtb) 感染会导致细菌存在的潜伏性结核病。 改变代谢并表现出表型药物耐受性用于维持代谢的生物途径。 人们对体内平衡、燃料复苏和复制知之甚少。 休眠或静止的一个重要组成部分是细胞壁中碳和能源的储存 复苏后可回收的脂质 Mtb 会产生“储存脂质”三酰甘油 (TAG) 和蜡。 酯（WE）在稳定期后期和对通常与休眠期间相关的应激做出反应。 在向主动复制的转变过程中，人们相信这些脂质被动员起来并用作代谢物质 然而，我们最近描述了非常长的资源。 Mtb 的链三酰甘油 (LCTAG) 和霉菌蜡酯 (MWE) 这些脂质是从 Mtb 出口的。 LCTAG 的命运由 MmpL11 转运蛋白转运至分枝杆菌外膜或荚膜。 LCTAG 和 MWE 是否处于细胞外尚不清楚，但 LCTAG 和 MWE 的正确定位是未知的。 对于 Mtb 毒力和生理学很重要，因为 1) MmpL11 是毒力所必需的，2) Mtb mmpL11 突变体减少了体外非复制持久模型的复苏。 本地化的 LCTAG 和 MWE 可用作共享资源，以维持生存能力并从 非复制持久性。 根据我们的数据，我们发现 Mtb 会水解、进口和利用出口的储存脂质 促进缺氧和营养受限环境中的复苏。 我们建议通过 1) 确定 LCTAG 和 MWE 对 Mtb 的贡献来检验这一假设 从非复制持久性中复苏，以及 2) 定义参与 LCTAG 和 MWE 的蛋白质 这项探索性研究将公正的方法与遗传和循环利用相结合。 生化分析研究 Mtb 细胞重塑的重要生物学过程 代谢。