Identification of novel DNA repair mechanisms in Mycobacterium tuberculosis

结核分枝杆菌新型 DNA 修复机制的鉴定

基本信息

批准号：
8223133
负责人：
Pallavi Ghosh
金额：
$ 18.94万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-02-04 至 2014-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8223133
关键词：
Alveolar Macrophages Antibiotics Antitubercular Agents Bacteria Base Excision Repairs DNA DNA Damage DNA Repair DNA Repair Enzymes DNA Repair Gene DNA Repair Pathway Data Disease Drug Delivery Systems Ensure Environment Escherichia coli Extreme drug resistant tuberculosis Gene Expression Gene Expression Regulation Generations Genes Genetic Screening Genetic Transcription Genome Genus Mycobacterium Goals Growth Homologous Gene Host Defense Mechanism Hydrogen Peroxide Hypersensitivity Infection Investigation Laboratories Methods Mismatch Repair Mitomycins Multi-Drug Resistance Mutation Mycobacterium smegmatis Mycobacterium tuberculosis Nitrogen Nonhomologous DNA End Joining Nucleotide Excision Repair Organism Oxidative Stress Oxygen Pathway interactions Phagocytosis Pharmaceutical Preparations Phase Population Reactive Oxygen Species Regimen Regulator Genes Resistance Respiratory Burst Role SOS Response System Techniques Testing Time Tuberculosis Work antimicrobial assault base biological adaptation to stress design effective therapy genetic regulatory protein genome-wide insight intein interest killings macrophage mutant mycobacterial novel pathogen pathogenic bacteria public health relevance recombinational repair repaired research study response success therapeutic target tuberculosis drugs tuberculosis treatment

项目摘要

DESCRIPTION (provided by applicant): Project Summary: Tuberculosis (TB), caused by Mycobacterium tuberculosis infects about 2 billion- a third- of the world's population. The success of the pathogen can be attributed to its extraordinary ability to survive indefinitely in the host. The treatment of TB requires a prolonged regimen of three anti-tuberculosis drugs to ensure complete eradication of a sub-population that continues to persist against antibiotics. The emergence of multi-drug resistant and extremely drug resistant TB is a tremendous concern as it completely eliminates all treatment options as well as overturns the effort made by WHO to control the spread of this disease. Therefore an understanding of the mechanism of persistence of M. tuberculosis inside the host is imperative for designing a short and effective treatment against the disease. During the course of infection M. tuberculosis is challenged with a variety of host defense mechanisms which the pathogen has to overcome. Of these, the challenges faced during the early phase of infection are perhaps the most critical for the pathogen to survive so as to establish a successful infection. This primarily constitutes the respiratory burst that occurs upon phagocytosis of the bacteria by alveolar macrophages and results in the generation of reactive oxygen and nitrogen intermediates. Whereas most pathogenic bacteria are cleared by these antimicrobial activities in the infected macrophages, M. tuberculosis has evolved mechanisms to subvert these challenges as well as to actively repair the damage caused. The bases in DNA are particularly susceptible to damage by these reactive oxygen and nitrogen species- the bacteria must therefore possess active mechanisms to repair the damage in order to ensure the survival of the pathogen. Previous work suggests that mycobacteria possess most of the DNA damage repair systems utilized by other bacteria; in addition it has a number of novel genes and pathways as well. This is not very surprising considering that M. tuberculosis resides in an environment rich in agents that can damage DNA. The project here proposes to identify novel DNA stress response pathways in the pathogen which will help in better understanding the mechanisms utilized by the bacteria to repair its DNA and are simultaneously very attractive as therapeutic targets. Our preliminary work has identified several novel genes that have previously not been shown to be involved in DNA damage repair in the surrogate host M. smegmatis. While the genes identified from M. smegmatis provide an invaluable insight into mycobacterial survival strategies against oxidative stress and strongly support the hypothesis that key repair pathways remain to be discovered, it is likely that M. tuberculosis could have additional genes for its survival because of its obligate intracellular growth requirement. In this revised submission we propose to identify novel DNA damage repair pathways in the pathogen, M. tuberculosis as well as study the involvement of regulatory proteins identified in the preliminary screen.) ) PUBLIC HEALTH RELEVANCE: Project)Narrative) ) Tuberculosis,)caused)by)M.)tuberculosis)infects)nearly)a)third)of)the)world's) population)and)kills)about)2)million)people)in)the)world)every)year.)Developing)new) drugs)for)the)disease)requires)a)better)understanding)of)the)mechanisms)the) pathogen)utilizes)to)persist)in)the)challenging)environment.)In)this)project)we)study) the)novel)mechanisms)used)by)bacteria)to)counter)the)constant)assault)on)its)DNA) by)the)reactive)oxygen)species)present)in)the)oxidizing)environment)of)macrophages) where)it)resides)for)prolonged)periods)of)time.))

描述（由申请人提供）：项目摘要：结核分枝杆菌引起的结核病（结核病）感染了大约20亿次世界人口。病原体的成功可以归因于其在宿主中无限期生存的非凡能力。结核病的治疗需要长时间的三种抗结核药物的治疗方法，以确保完全消除继续持续抵抗抗生素的亚种群。多药耐药和极度耐药性结核病的出现是一个巨大的问题，因为它完全消除了所有治疗选择，并推翻了谁控制这种疾病的传播所做的努力。因此，必须了解宿主体内结核分枝杆菌持续性的机制，对于设计对疾病的短暂有效治疗至关重要。在感染过程中，肺结核的挑战是多种宿主防御机制必须克服的宿主防御机制。其中，在感染早期阶段所面临的挑战可能是病原体生存最重要的挑战，以建立成功的感染。这主要构成肺泡巨噬细胞吞噬细胞的吞噬作用后发生的呼吸爆发，并导致活性氧和氮中间体的产生。尽管这些抗菌活性在感染的巨噬细胞中清除了大多数病原菌，但结核分枝杆菌已经发展出了颠覆这些挑战以及积极修复造成的损害的机制。 DNA中的碱基特别容易受到这些活性氧和氮种的损害 - 因此，细菌必须具有维修损伤的主动机制，以确保病原体的存活。先前的工作表明，分枝杆菌具有其他细菌使用的大多数DNA损伤修复系统。此外，它还具有许多新颖的基因和途径。考虑到结核分枝杆菌存在于富含DNA的药物的环境中，这并不奇怪。这里的项目提议识别病原体中新型的DNA应力反应途径，这将有助于更好地理解细菌修复其DNA的机制，并同时与治疗靶标相同。我们的初步工作已经确定了几个新型基因，这些基因以前尚未证明与替代宿主M. smegmatis中的DNA损伤修复有关。虽然Smegmatis鉴定出的基因为抗氧化应激的分枝杆菌生存策略提供了宝贵的见解，并强烈支持以下假设：关键的修复途径仍有待发现，但结核分枝杆菌可能具有额外的基因，因为其具有强大的细胞内生长需求。在此修订后的提交中，我们建议鉴定病原体中的新型DNA损伤修复途径，结核分枝杆菌，并研究了初步筛查中确定的调节蛋白的参与。））公共卫生相关性：）结核病，）。病原体）利用））在）挑战性的环境中。）in）project）我们研究）neks）nekage of））of））dna）dna）dna））of））of）of））oxyge））oxyge））））））））氧化环境）））it）居住）时间）。））））））