Regulatory networks involved in Mycobacterium tuberculosis persistence

参与结核分枝杆菌持续存在的监管网络

• 批准号: 7755327
• 负责人: Petros C Karakousis
• 金额: $ 53.91万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-15 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7755327
• 关键词: Adherence; Animal Model; Antibiotics; Bacillus (bacterium); Bacteria; Cells; Complex; Development; Drug Interactions; Drug resistance; Enzymes; Extreme drug resistant tuberculosis; Feedback; Genes; Germ; Growth; Guanosine; HIV; Human; Hydrolysis; Immune; In Vitro; Infection; Lead; Lesion; Lung; Mammalian Cell; Mediating; Medical; Metabolism; Molecular; Multi-Drug Resistance; Mycobacterium tuberculosis; Organism; Pathology; Pathway interactions; Patients; Pharmaceutical Preparations; Play; Polyphosphates; Recombinants; Role; Stress; Testing; Time; Treatment Protocols; Tuberculosis; Up-Regulation; bactericide; chemotherapy; drug development; improved; inhibitor/antagonist; killings; macrophage; overexpression; public health relevance; reconstitution; response; small molecule; tuberculosis treatment

DESCRIPTION (provided by applicant): Tuberculosis (TB) is a major AIDS-related infection. The lengthy and cumbersome therapy currently available to treat TB has contributed to medical nonadherence and the emerging problems of multi-drug resistant (MDR)- and extensive-drug resistant (XDR)-TB. This prolonged therapy reflects the ability of Mycobacterium tuberculosis (Mtb) to persist in the infected host in a nonreplicating state characterized by antibiotic tolerance. The molecular mechanisms underlying Mtb growth restriction are unknown. We and others have shown that the alarmone hyperphosphorylated guanosine ((p)ppGpp) and the regulatory molecule inorganic polyphosphate (poly P) play a role in Mtb survival under growth-limiting conditions. However, the regulatory relationship between (p)ppGpp and poly P and the precise role of this network on Mtb growth restriction and antibiotic tolerance have not been elucidated. In this proposal, we plan to use Mtb recombinant strains conditionally overexpressing RelMtb, the stringent response enzyme responsible for (p)ppGpp synthesis, in order to test the hypothesis that (p)ppGpp is a molecular "brake" responsible for Mtb growth restriction and antibiotic tolerance. Next, using both poly P-deficient and poly P-accumulating Mtb recombinant strains, we will test the hypothesis that poly P regulates Mtb growth restriction and antibiotic tolerance. Finally, we will test the hypothesis that (p)ppGpp and poly P constitute a complex, feedback regulatory loop involving poly P- dependent expression of relMtb and (p)ppGpp-mediated inhibition of poly P hydrolysis. Although poly P is present in all cells, the highly-conserved bacterial enzyme responsible for poly P synthesis in Mtb has not been identified in mammalian cells, thus making it a potentially attractive target for drug development. A small molecule inhibitor of RelMtb would be predicted to lead to reduced Mtb synthesis of (p)ppGpp. Inhibition of this regulatory network may lead to reduced survival of persistent bacilli, with the potential to shorten the duration of TB chemotherapy. In addition to improving medical adherence and reducing the potential for the development of drug resistance, an abbreviated drug regimen to treat active TB could be especially useful in HIV co-infected patients, since drug-drug interactions and immune reconstitution may complicate the concurrent management of both infections. PUBLIC HEALTH RELEVANCE: TB treatment requires at least 6 months of therapy because the germs that cause TB can go "dormant" when they encounter stress, becoming very difficult to kill with current antibiotics, which kill dividing bacteria. In this proposal, we plan to study some of the important mechanisms that lead TB germs to stop dividing. If we can figure out how TB germs go "dormant", we may be able to develop new ways to attack these germs and shorten the time it takes to cure this major AIDS-related infection.

描述（由申请人提供）：结核病（TB）是与艾滋病相关的主要感染。目前可用于治疗结核病的漫长而繁琐的疗法导致了医学不遵守性以及耐多药（MDR）和广泛的耐药性（XDR）-TB的新兴问题。这种长时间的治疗反映了结核分枝杆菌（MTB）在以抗生素耐受为特征的不复制状态下持续的结核分枝杆菌（MTB）的能力。 MTB生长限制的分子机制尚不清楚。我们和其他人已经表明，警报器高磷酸化的鸟嘌呤（（P）PPGPP）和调节分子无机聚磷酸盐（Poly P）在生长限制条件下在MTB存活中起作用。但是，尚未阐明（P）PPGPP和Poly P之间的调节关系以及该网络在MTB生长限制和抗生素耐受性上的确切作用。在此提案中，我们计划使用有条件过表达RELMTB的MTB重组菌株，该酶的严格响应酶负责（P）PPGPP合成，以检验（P）PPGPP是MTB生长限制和抗生素耐受性的分子“制动”的假设。接下来，使用聚p缺陷和聚p-蓄积的MTB重组菌株，我们将检验以下假设：聚P调节MTB生长限制和抗生素耐受性。最后，我们将检验以下假设：PPGPP和Poly P构成了一个复杂的反馈调节环，涉及RELMTB的聚P-依赖性表达，并且（P）PPGPP介导的Poly P水解抑制。尽管在所有细胞中都存在聚P，但在哺乳动物细胞中尚未鉴定出负责MTB中Poly P合成的高度保存的细菌酶，从而使其成为药物发育的潜在吸引人的靶标。 RELMTB的小分子抑制剂将预计会导致（P）PPGPP的MTB合成降低。抑制这种调节网络可能会导致持续性杆菌的存活降低，并有可能缩短结核病化疗的持续时间。除了提高医疗依从性并降低耐药性发展的潜力外，由于药物 - 药物相互作用和免疫结构可能使两种感染的同时治疗复杂化，因此在HIV共感染的患者中，一种缩写的药物治疗活性结核病可能特别有用。公共卫生相关性：结核病治疗需要至少6个月的治疗，因为当遇到压力时会导致结核病的细菌可能会“休眠”，并且很难用当前抗生素杀死，从而杀死分裂细菌。在此提案中，我们计划研究导致结核病细菌停止分裂的一些重要机制。如果我们能弄清楚结核菌细菌如何“休眠”，我们可能能够开发出攻击这些细菌的新方法，并缩短治愈与艾滋病相关的主要感染所需的时间。