Targeting a New Essential Virulence Mechanism in Drug-Resistant Mycobacteria

针对耐药分枝杆菌的新基本毒力机制

基本信息

批准号：
8802858
负责人：
Christina Leigh Stallings
金额：
$ 20.42万
依托单位：
WASHINGTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-03-01 至 2016-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8802858
关键词：
Achievement Acute Animals Anti-Bacterial Agents Antibiotic Resistance Antibiotics Bacteria Bacterial Infections Biological Assay Catalytic Domain Cell surface Cells Cessation of life Chemicals Chronic Clinical Trials Development Diphosphates Disease Drug Targeting Drug resistance Drug resistance in tuberculosis Drug-sensitive Enterococcus faecalis Enzymes Epidemic Genetic Transcription Genotoxic Stress Genus Mycobacterium Guanine Nucleotides Guanosine Triphosphate Health Homologous Gene Human Hydrolase Hydrolysis Hypoxia In Vitro Infection Lead Libraries Mediating Metabolic Molecular Morphology Mus Mutation Mycobacterium tuberculosis New Agents Nucleotides Oxidative Stress Pharmaceutical Preparations Phase Phosphodiesterase Inhibitors Population Production Proliferating Proteins RNA Reporting Role Signaling Molecule Staging Staphylococcus aureus Starvation Streptococcus pyogenes Stress Therapeutic Intervention Tuberculosis Virulence World Health Organization acid stress base biological adaptation to stress combat design drug resistant bacteria high throughput screening in vitro Assay in vivo inhibitor/antagonist killings mutant mycobacterial novel therapeutics pathogen phosphoric diester hydrolase pre-clinical protein structure research study resistant strain response scaffold small molecule tuberculosis treatment

项目摘要

DESCRIPTION (provided by applicant): Mycobacterium tuberculosis (Mtb) infects at least 30% of the world's population and causes an estimated 1.8 million deaths a year. The emergence of drug-resistant Mtb strains, which constitute 20% of previously treated tuberculosis (TB) cases, has exacerbated this already alarming epidemic. The inadequacies of present TB therapies demand the discovery of new agents to treat Mtb infection. We have discovered a role for the Mtb protein RelMtb that is essential for acute and chronic Mtb infection in mice. RelMtb both synthesizes and hydrolyzes an important bacterial signaling molecule termed (p)ppGpp. We have shown that it is specifically the (p)ppGpp hydrolase activity of RelMtb that is required for all stages of Mtb infection. This indicates that both active and chronic TB could be treated by inhibiting the RelMtb hydrolase domain with a small molecule antibiotic. Importantly, RelMtb has not yet been exploited as an antibacterial target and, therefore, drug-resistant Mtb strains with mutations in other drug targets will still be susceptible to chemical inhibitors of RelMtb. The objectives of the first phase of this project are to 1) develop assays to screen for inhibitors of RelMtb-mediated (p)ppGpp hydrolysis and 2) validate RelMtb as a druggable target. Specifically, we will pursue the following 3 Aims: R21-1. Develop non-radioactive high-throughput in vitro assays of RelMtb (p)ppGpp hydrolase activity. R21-2. Develop in vivo mycobacterial cell-based assays to screen for inhibitors of RelMtb activity. R21-3. Conduct pilot screens with small focused compound libraries to demonstrate suitability of assays for high throughput screening. The objectives of the second phase of this project are to 1) identify a lead compound, 2) optimize the lead compound, and 3) target RelMtb-mediated (p)ppGpp hydrolysis to inhibit Mtb viability and infection. Specifically, we will pursue the following 3 Aims: R33-1. Screen select compound libraries in our in vitro and in vivo assays. R33-2. Design chemical inhibitors to optimize activity against RelMtb based on the scaffold of successful inhibitors, selectivity against RelMtb, metabolic stability, and the RelMtb protein structure. R33-3. Demonstrate preclinical proof-of-concept for inhibitors to combat Mtb infection and the drug-resistance problem. Successful completion of these aims will lead to the development of a critically needed new strategy for TB therapy. RelMtb homologs are conserved in all bacteria, but not in animals, and thus our findings could impact the treatment of other pathogenic and notoriously drug-resistant bacteria including Enterococcus faecalis, Streptococcus pyogenes, and Staphylococcus aureus. Achievement of our aims will characterize and validate (p)ppGpp hydrolases as a target for therapeutic intervention against drug-resistant bacterial pathogens.

描述（由申请人提供）：结核分枝杆菌（MTB）感染了世界人口的至少30％，估计每年死亡180万。抗药性MTB菌株的出现占先前治疗的结核病（TB）病例的20％，这使这种已经令人震惊的流行病加剧了。当前结核病疗法的不足要求发现新药物以治疗MTB感染。我们已经发现了MTB蛋白RELMTB的作用，这对于小鼠的急性和慢性MTB感染至关重要。 Relmtb合成和水解称为PPGPP的重要细菌信号分子（P）。我们已经表明，MTB感染的所有阶段都需要特别是RELMTB的（P）PPGPP水解酶活性。这表明活动和慢性结核病都可以通过用小分子抗生素抑制RELMTB水解酶结构域。重要的是，RELMTB尚未被用作抗菌靶标，因此，在其他药物靶标中具有突变的药物耐药的MTB菌株仍然容易受到RELMTB的化学抑制剂的影响。该项目的第一阶段的目标是1）开发用于筛选RELMTB介导的（P）PPGPP水解抑制剂的测定法，并将Relmtb验证为可药物目标。具体来说，我们将追求以下3个目标：R21-1。在RELMTB（P）PPGPP水解酶活性的体外测定中开发非放射性高通量。 R21-2。开发基于体内分枝杆菌细胞的测定法以筛选RELMTB活性抑制剂。 R21-3。用小型聚焦化合物库进行试点屏幕，以证明针对高通量筛选的测定法。该项目的第二阶段的目标是1）识别铅化合物，2）优化铅化合物，3）目标relmtb介导的（P）PPGPP水解以抑制MTB的生存能力和感染。具体来说，我们将追求以下3个目标：R33-1。屏幕在我们的体外和体内测定中选择化合物库。 R33-2。设计化学抑制剂，以基于成功抑制剂的支架，针对RERMTB的选择性，代谢稳定性和RELMTB蛋白结构来优化RELMTB的活性。 R33-3。证明了临床前概念概念抑制剂应对MTB感染和药物抗药性问题。这些目标的成功完成将导致制定急需的结核病治疗策略。 RELMTB同源物在所有细菌中都是保守的，但在动物中均保守，因此我们的发现可能会影响其他致病性和臭名昭著的耐药细菌的治疗，包括粪便肠球菌，甲链球菌，增生链球菌，以及金黄色葡萄球菌。我们目标的实现将表征和验证（P）PPGPP水解酶是针对耐药细菌病原体治疗干预的靶标。