SIGMA: Small molecule Inhibitors targeting the Genetic determinants of Mutagenesis and Adaptability in Mycobacterium tuberculosis

为了在各种化学和寄主胁迫下生存，病原菌的同基因种群通过(I)形成具有不同代谢状态的瞬时亚群，(Ii)可诱导的代谢重塑和(Iii)胁迫诱导的突变而产生表型变异。表型可变性助长了病原菌进化抗生素耐药性的能力，因此，操纵表型可变性本身的下一代抗生素疗法将是革命性的。然而，在感染相关条件下具有临床意义的非模式致病菌中，我们对表型可变性的遗传决定因素知之甚少，也不知道如何用小分子调节它们。结核分枝杆菌的表型变异导致了结核病的标志性治疗挑战，结核病每年导致140万人死亡。因此，我们建议系统地表征结核分枝杆菌表型可变性的遗传决定因素以及调节它们的小分子，以便形成下一代治疗的原型。我们将结合新的方法学、分枝杆菌学、功能基因组学和化学生物学的发展，在四个方面：1.阐明代谢亚群的精细结构，并确定这种精细结构的遗传和小分子调节因子。2.确定代谢重塑所必需的全套基因，以在与寄主相关的不允许生长的胁迫条件下生存。3.鉴定感染相关应激诱导突变的遗传和小分子调控因子。4.探索三种新的消除结核分枝杆菌的模式，以加速其杀灭，消除其耐药亚群，并抑制耐药性的演变。

To survive myriad chemical and host stresses, isogenic populations of pathogenic bacteria generate phenotypic variability by (i) developing transient subpopulations with distinct metabolic states, (ii) inducible metabolic remodelling, and (iii) stress-induced mutagenesis. Phenotypic variability fuels the ability of pathogenic bacteria to evolve antibiotic resistance, therefore next generation antibiotic therapies which manipulate phenotypic variability itself would be transformative. However, in clinically significant non-model pathogenic bacteria under infection-relevant conditions, we know little either about genetic determinants of phenotypic variability, or about how to modulate them with small molecules. Phenotypic variability in Mycobacterium tuberculosis causes the signature treatment challenges of tuberculosis, a disease which kills 1.4 million people annually. Therefore, we propose to systematically characterise the genetic determinants of phenotypic variability in M. tuberculosis as well as small molecules which modulate them in order to prototype next generation therapies. We will combine development of new methodology, mycobacteriology, functional genomics, and chemical biology in four aims: 1. to elucidate fine structure of metabolic subpopulations and identify genetic and small-molecule modulators of this fine structure. 2. to identify the comprehensive set of genes essential for metabolic remodelling to survive host-related stress conditions that do not permit growth. 3. to identify genetic and small-molecule modulators of inducible mutagenesis under infection-relevant stress. 4. to investigate three new modes of M. tuberculosis eradication to accelerate its killing, eliminate its antibiotic-tolerant subpopulations, and suppress evolution of resistance.