Triacylglycerol metabolism and Mtb virulence

描述（由申请人提供）：结核分枝杆菌能够以静止形式在人类宿主体内持续多年，只有在宿主免疫系统衰退后才能重新激活并产生传染性疾病。细菌的静止形式被认为处于由宿主适应性免疫诱导的生长停滞状态。因此，了解在复制和非复制状态之间的转换过程中的代谢适应机制将有助于开发针对持续状态下独特代谢途径的抗结核药物。本研究的目的是探讨三酰甘油（TAG）代谢在M.结核病的持续和再生。该建议是基于实验推导的代谢模型的M。结核病，其标记有在建立持续状态期间从用于生物合成前体合成的关键中心代谢途径朝向TAG形成的协调碳通量。M中的TAG积累。结核病被认为是其在疾病激活期间长期持续和再生的关键碳和能量燃料。为了验证这一假设，我们采用了一种新的方法来设计TAG代谢途径，从而可以操纵TAG代谢的动力学来评估其在M.结核休眠和再生。TAG缺陷型M.首先通过采用将主要TAG合酶基因的靶向缺失与高活性TAG脂肪酶基因的条件性高表达相结合的工程化策略来产生结核菌株。并对TAG代谢动力学及TAG在M.在体外休眠模型和兔结核模型中评估结核存活和再生长。如果成功，该项目的发现有望提供新的研究方向，重点关注TAG代谢，从而开发新药来解决持久性杆菌并防止疾病重新激活。此外，TAG缺陷型M.结核病可能是结核病疫苗的潜在候选者。 公共卫生相关性：该项目的目标是研究三酰甘油（TAG）代谢在结核分枝杆菌休眠期存活和疾病再激活期细菌再生长中的作用。实验过程结合了联合收割机分子工程和生化/生理分析，使用M.结核菌休眠的体外和体内研究。该计划有望获得结核杆菌在不同生长状态之间过渡期间代谢适应机制的新见解，并提供解决持续感染和疾病再激活的新策略。

DESCRIPTION (provided by applicant): Mycobacterium tuberculosis has the ability to persist for many years in a quiescent form within a human host, only to reactivate and produce communicable disease after the host immune system falters. The quiescent form of the bacteria is believed to be in a state of growth arrest induced by host adaptive immunity. Thus, understanding the mechanisms of metabolic adaptation during the shift between replicative and nonreplicative state will facilitate the development of anti-tuberculosis drugs that target unique metabolic pathways in the persistent state. The goal of this project is to dissect the roles of triacylglycerol (TAG) metabolism in M. tuberculosis persistence and regrowth. The proposal is based on an experiment-derived metabolic model of M. tuberculosis, which is marked with a coordinated carbon flux from key central metabolic pathways for biosynthetic precursor synthesis towards the formation of TAG during establishment of the persistent state. TAG accumulation in M. tuberculosis is proposed to serve as critical carbon and energy fuel for both its long-term persistence and regrowth during activation of the disease. To test the hypothesis, a novel approach is utilized to engineer the TAG metabolic pathways so that the dynamics of TAG metabolism can be manipulated to evaluate its functions during M. tuberculosis dormancy and regrowth. A TAG-deficient M. tuberculosis strain will first be generated by employing an engineering strategy that combines targeted deletion of a major TAG synthase gene with the conditional high expression of a highly active TAG lipase gene. Then, the dynamics of TAG metabolism and roles of TAG on M. tuberculosis survival and re-growth will be assessed in in vitro dormancy models and in a rabbit tuberculosis model. If successful, findings from this project are expected to provide new lines of research focusing on TAG metabolism from which new drugs could be developed to tackle the persistent bacilli and to prevent the disease from reactivation. Moreover, the TAG-deficient M. tuberculosis could be a potential candidate for a tuberculosis vaccine. PUBLIC HEALTH RELEVANCE: The goal of the program is to study the roles of triacylglycerol (TAG) metabolism in Mycobacterium tuberculosis survival during dormancy and bacterial re-growth during disease reactivation. The experimental procedures combine molecular engineering and biochemical/physiological assays using models of M. tuberculosis dormancy in vitro and in vivo. The program is expected to gain new insights on the metabolic adaptation mechanisms of the tubercle bacilli during transition between different growth states and to offer new strategies to tackle the persistent infection and disease reactivation.