Genetic determinants of susceptibility to mycobacterial infections

分枝杆菌感染易感性的遗传决定因素

• 批准号: 8040129
• 负责人: PHILIPPE GROS
• 金额: $ 17.73万
• 依托单位: MCGILL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-09-30 至 2016-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8040129
• 关键词: Accounting; Aerosols; Affect; Alleles; Animal Model; Antibiotic Resistance; Area; Bacterial Genes; Biochemical; Biochemical Genetics; Breeding; Cell membrane; Cell physiology; Chromosomes, Human, Pair 7; Code; Collaborations; Communicable Diseases; Congenic Mice; DNA; Defense Mechanisms; Dendritic Cells; Developing Countries; Disease; Endosomes; Exposure to; Gene Expression; Gene Expression Profile; Gene Proteins; Genes; Genetic; Genetic Determinism; Genomics; Genus Mycobacterium; Health; Heterodimerization; Homozygote; Host Defense; Host Defense Mechanism; Human; IRF1 gene; Immune response; Immunity; In Vitro; Individual; Infection; Institutes; Intervention; Laboratories; Leprosy; Lung; Maps; Measures; Mediating; Membrane; Metals; Methods; Molecular; Monitor; Mouse Strains; Mus; Mutation; Mycobacterium Infections; Mycobacterium tuberculosis; Pathogenesis; Pathway interactions; Patients; Phagocytes; Phagosomes; Population; Predisposition; Property; Proteins; Pulmonary Tuberculosis; Recycling; Regulation; Resistance; Role; Secondary Protein Structure; Series; Severities; Signal Transduction; Site; Sorting - Cell Movement; Testing; Time; Transcript; Transgenic Mice; Travel; Tuberculosis; United States National Institutes of Health; Variant; Virulent; base; chelation; chromatin immunoprecipitation; cohort; congenic; drug discovery; efflux pump; gene cloning; gene discovery; genetic analysis; genome-wide; immune function; in vivo; loss of function; loss of function mutation; macrophage; microbial; microcytic anemia; monocyte; mortality; mouse model; mycobacterial; novel; pathogen; research study; response; transcription factor

DESCRIPTION (provided by applicant): Infectious diseases are a major, re-emerging health problem, accounting for 33% of the world mortality (17 million/year). The emergence of new virulent variants, widespread resistance to antibiotics, and increased worldwide travel are but a few factors that have increased the severity of the problem not only in developing countries, but also for people traveling to these regions, and for individuals with reduced immune functions. Mycobacterial infections continue to be a serious health threat, causing tuberculosis in otherwise healthy individuals, and causing disseminated infections in immuno-suppressed patients. The host defense mechanisms against these infections, including the effector functions of macrophages and parameters of protective immunity, need to be better understood. Such host defense mechanisms can manifest themselves as genetic determinants of innate resistance or susceptibility to infections in human populations, and in corresponding animal models. Using a genetic approach in mice, we have detected a major locus on chromosome 7, designated Trl3, which controls susceptibility to pulmonary tuberculosis in mice. In the first specific aim of this application, we propose to identify the gene and protein that control this differential susceptibility. This will be done by creating and characterizing a series of congenic and subcongenic mouse strains, in which Trl3 has been isolated by selective breeding. The minimal genetic interval will be carefully scrutinized for the presence of positional candidates that will then be systematically tested in transgenic mice in vivo and in macrophages in vitro. The function of the protein product of the gene and its role in macrophage and dendritic cell defenses against tuberculosis will be investigated. Independently, we have uncovered that a mutation in the transcription factor IRF8 causes extreme susceptibility to pulmonary tuberculosis in mice, and have identified a homozygote loss-of-function IRF8 mutation in a patient suffering from Mendelian Susceptibility to Mycobacterial Disease (MSMD). In the second aim of this application we propose to implement genome-wide methods, including transcript profiling with microarrays and chromatin immunoprecipitation (ChIP) and genomic DNA arrays (ChIP on chip) to systematically identify genes regulated by IRF8, and that may code for key defense mechanisms of macrophages against mycobacteria. A series of in vitro and in vivo experiments are also proposed to validate IRF8 regulation of the identified targets, and to evaluate their role in macrophage defenses against mycobacteria. We also propose to assess the role of these targets in human mycobacterial infections, by monitoring their integrity in a cohort of 300 patients suffering from MSMD. PUBLIC HEALTH RELEVANCE: Infectious diseases are a major, re-emerging health problem, accounting for 33% of the world mortality (17 million/year). Mycobacterial infections continue to be a serious health threat, causing tuberculosis in otherwise healthy individuals, and causing disseminated infections in immuno-suppressed patients. The host defense mechanisms against these infections, including the anti-mycobacterial effector functions of macrophages and parameters of protective immunity, need to be better understood. Such host defense mechanisms can manifest themselves as genetic determinants of innate resistance or susceptibility to infections in human populations, and in corresponding animal models. The identification and characterization of the genes involved will not only enable a better understanding of infection pathogenesis and host response to it, but may also identify novel targets for drug discovery and pharmacological interventions in these infections.

描述(申请人提供)：传染病是一个主要的、重新出现的健康问题，占世界死亡率(1700万/年)的33%。新的毒力变种的出现，对抗生素的广泛抗药性，以及全球旅行的增加，只是增加了问题的严重性的几个因素，不仅在发展中国家，而且对前往这些地区的人和免疫功能低下的人来说也是如此。分枝杆菌感染仍然是一个严重的健康威胁，在其他健康的人中引起结核病，并在免疫抑制的患者中造成播散性感染。对这些感染的宿主防御机制，包括巨噬细胞的效应功能和保护性免疫参数，需要更好地了解。这种宿主防御机制可以在人类群体和相应的动物模型中表现为先天抵抗力或对感染的易感性的遗传决定因素。通过在小鼠身上使用遗传方法，我们在7号染色体上检测到了一个名为Trl3的主要基因座，它控制着小鼠对肺结核的易感性。在这项应用的第一个具体目标中，我们建议识别控制这种差异敏感性的基因和蛋白质。这将通过创造和鉴定一系列同源和亚同源小鼠品系来实现，其中Trl3已经通过选择性育种被分离出来。最小的遗传间隔将被仔细检查是否存在位置候选，然后将在体内转基因小鼠和体外巨噬细胞中进行系统测试。该基因的蛋白产物的功能及其在巨噬细胞和树突状细胞防御结核病中的作用将被研究。独立地，我们已经发现转录因子IRF8的突变导致小鼠对肺结核的极端易感性，并在一名患有孟德尔分枝杆菌病(MSMD)易感性的患者中发现了纯合子功能丧失的IRF8突变。在本申请的第二个目标中，我们建议实施全基因组方法，包括利用微阵列和染色质免疫沉淀(CHIP)和基因组DNA阵列(芯片上)系统地识别受IRF8调控的基因，并可能编码巨噬细胞对分枝杆菌的关键防御机制。还提出了一系列体外和体内实验，以验证IRF8对已识别靶点的调节，并评估它们在巨噬细胞防御分枝杆菌中的作用。我们还建议通过在300名MSMD患者队列中监测这些靶点的完整性，来评估这些靶点在人类分枝杆菌感染中的作用。 公共卫生相关性：传染病是一个重大的、重新出现的健康问题，占世界死亡率(1700万/年)的33%。分枝杆菌感染仍然是一个严重的健康威胁，在其他健康的人中引起结核病，并在免疫抑制的患者中造成播散性感染。对这些感染的宿主防御机制，包括巨噬细胞的抗分枝杆菌效应功能和保护性免疫参数，需要更好地了解。这种宿主防御机制可以在人类群体和相应的动物模型中表现为先天抵抗力或对感染的易感性的遗传决定因素。相关基因的识别和鉴定不仅有助于更好地了解感染的发病机制和宿主对感染的反应，还可能为治疗这些感染的药物开发和药物干预寻找新的靶点。