Evaluation of novel TB drug regimens by targeting resuscitation promoting factor-dependent persistent Mycobacterium tuberculosis in the Cornell model

结核病虽然可以治愈，但仍然是世界上最大的杀手之一。它每年在全世界造成近200万人死亡。98%的结核病死亡发生在发展中国家，主要影响处于生产年龄的年轻人。25万结核病死亡者也感染了艾滋病毒，免疫系统减弱，其中大多数人在非洲。结核病尤其影响到最脆弱的人群，包括儿童、最贫穷者和营养不良者。结核病是由一种叫做结核分枝杆菌的细菌引起的。这种疾病的一个重要特征是细菌具有在人体内生长和存活很长时间的不寻常能力。因此，据估计，20亿人，相当于世界总人口的三分之一，感染了这种细菌，它引起不明显的潜伏感染，导致5-10%的活动性疾病的终生风险。这些持久存在的细菌不能用标准的微生物方法培养，也不能被目前的结核病药物杀死。因此，肺结核的治疗需要很长一段时间用四种药物才能使患者痊愈。这种长期治疗非常难以实施，特别是在发展中国家，因为缺乏负担能力和有限的医疗服务和基础设施。该研究旨在确定和量化结核病感染小鼠在治疗前，治疗期间和治疗后的持久性细菌，以预测人类结核病治疗的结果。通过添加复苏促进因子（RPF），这些复苏促进因子是由M.结核病重新开始生长。我们最近在小鼠中的研究表明，在当前治疗药物方案中添加的高剂量利福平或贝达喹啉能够杀死持续的RPF复苏细菌。这意味着治疗时间可以缩短，复发率降低。我们还修改了康奈尔模型，以更好地模拟人类感染富集持久性细菌，并确定其清除。在这项提案中，我们将应用我们从使用一套新型药物方案研究小鼠中学到的相同原理和技术来预测人类结核病治疗的结果，特别是疾病复发。我们将在小鼠中建立一个模型系统作为试验平台，以评估新药方案的效力，然后再将其应用于更昂贵和耗时的人体试验。

Tuberculosis, although curable, still remains one of the biggest killers in the world. It kills nearly 2 million people worldwide every year. 98% of tuberculosis deaths are in the developing world affecting mostly young adults in their productive years. A quarter of a million tuberculosis deaths are also infected with HIV with weakened immune systems, most of these people are in Africa. Tuberculosis especially affects the most vulnerable populations including children, the poorest and malnourished. Tuberculosis is caused by the bacterium called Mycobacterium tuberculosis. One important characteristic of this disease is that the bacterium has an unusual ability to grow and survive for extended periods of time in human body. Therefore, it has been estimated that 2 billion people, equal to one-third of the world's total population, are infected with the bacterium in whom it causes unnoticeable latent infections that lead to a 5-10% lifetime risk of active disease. These persistent bacteria cannot be cultured using standard microbiological methods and are not killed by the current tuberculosis drugs. Therefore, tuberculosis treatment needs a long period of time with four drugs to cure the patients. This long-term treatment is extremely difficult to implement especially in developing countries because of lack of affordability and limited healthcare services and infrastructure. The proposed research aims to identify and quantify those persistent bacteria in tuberculosis-infected mice before, during and after treatment to predict the outcome of human tuberculosis treatment. The persistent bacteria will be "woken" by the addition of resuscitation promoting factors (RPF) which are proteins produced by M. tuberculosis to restart growth. We have shown in our recent study in mice that high-dose rifampicin or bedaquiline which was added in the current treatment drug regimen was able to kill persistent RPF resuscitated bacteria. This meant that the treatment duration could be shortened with a reduced relapse rate. We also modify the Cornell model to better mimic human infection by enriching persistent bacteria and determining their clearance. In this proposal, we will apply the same principals and techniques which we have learned from studying mice using a set of novel drug regimens to predict the outcome of human tuberculosis treatment, especially disease relapse. We will establish a model system in mice as a testbed to evaluate the potencies of new drug regimens prior to their application in more expensive and time-consuming human testing.