THE MICROBIOTA AND MUCOSAL IMMUNE RESPONSES IN THE DEVELOPMENT OF ASTHMA

哮喘发生过程中的微生物群和粘膜免疫反应

• 批准号: 9211283
• 负责人: Andrew Leon Kau
• 金额: $ 16.29万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-01 至 2020-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9211283
• 关键词: 8 year old; Acute; Algorithms; Allergic; Allergic Disease; Allergic inflammation; Animals; Antibodies; Antigens; Asthma; Bacteria; Bilateral; Binding; C57BL/6 Mouse; Cells; Child; Collection; Communities; Data; Data Set; Developed Countries; Developing Countries; Development; Diagnostic; Disease; Environment; Environmental Risk Factor; Extrinsic asthma; Flow Cytometry; Genetic; Germ-Free; Gnotobiotic; Grant; Habitats; House mice; Housing; Human; Hypersensitivity; Immune; Immune System Diseases; Immune response; Immune system; Immunoglobulin A; Individual; Inflammation; Intervention; Lead; Life Style; Lung; Lung diseases; Measurement; Microbe; Mucosal Immune Responses; Mus; Organism; Ovalbumin; Pathogenesis; Phenotype; Play; Predisposing Factor; Predisposition; Prevalence; Prevention strategy; Protocols documentation; RNA, Ribosomal, 16S; Respiratory System; Respiratory tract structure; Role; Sampling; Severities; Source; Specimen; Spleen; Surface; Techniques; Testing; Therapeutic; Time; Tissues; Transplantation; Variant; Vendor; airway inflammation; airway obstruction; allergic airway inflammation; allergic response; antigen challenge; asthmatic; base; disorder prevention; expectation; experimental study; follow-up; gut microbiota; interest; lymph nodes; member; microbial; microbial community; microbiota; mouse model; novel therapeutic intervention; prevent; public health relevance; respiratory; response; transcriptome sequencing; treatment strategy

 DESCRIPTION (provided by applicant): Asthma is a common allergic disorder characterized airway inflammation and obstruction. Though the prevalence of allergic diseases such as asthma is increasing, the reasons are incompletely understood. Environmental, rather than genetic, factors are thought to be primarily responsible, in part because of the association of allergy with Western lifestyles. This project will examine the hypothesis that the respiratory trac and gut microbiota is a key factor in conferring susceptibility or protection to allergic diseases, including asthma. Conventionally-raised and gnotobiotic mouse models of asthma will be used to test the hypothesis that a subset of bacteria, recognized by the immune system, is responsible for modulating susceptibility to asthma. The microbiota has previously been demonstrated to play a role in asthma pathogenesis in mice, but little is known about which microbes are responsible or even where (which body habitat) these organisms reside. In the first aim of this grant, mice from various vendors with different microbiota will be screened for microbial communities that predispose to allergic inflammation of their airways. Asthma will be induced by ovalbumin sensitization followed by antigen challenge. Severity of asthma in these animals will be determined by the degree of airway obstruction and tissue inflammation in their lungs. Their respiratory and intestinal microbiota will then be characterized by bacterial 16S rRNA sequencing, and BugFACS, a technique that allows isolation and identification of viable bacteria based on their binding to immunoglobulin A (IgA), the major antibody produced at mucosal surfaces. I will identify candidate bacterial strains that impact asthma phenotypes, initially by co-housing two types of mice - those harboring a microbiota associated with severe asthma and those with a microbiota associated with mild disease. Microbial source tracking algorithms, applied to 16S rRNA datasets generated from gut and respiratory tract microbiota, will be used to correlate observed changes in asthma severity upon co-housing with uni- or bilateral invasion of bacterial strains between cagemates. I will then transplant cultured invasive strains into the respiratory tract and/or gut of germ-free mice to establish whether these strains are causally related to asthma severity. In the second aim, a small group of well phenotyped 6-8 year old children, with and without asthma, will be sampled to characterize their respiratory and fecal microbiota by 16S rRNA sequencing and BugFACS. Representative respiratory tract and gut microbial communities will be transplanted from a) a representative asthmatic donor during an acute exacerbation, b) the same asthmatic at baseline, and c) a representative healthy non-asthmatic patient, into germ-free mice. Asthma will be induced in the recipient gnotobiotic mice that will then be characterized as described above. These aims will help dissect the relative contributions of respiratory tract and gut microbiota to disease pathogenesis and provide an approach for identifying bacterial strains that may have diagnostic and therapeutic utility.

 描述（由申请人提供）： 哮喘是一种常见的过敏性疾病，其特征是气道炎症和阻塞，尽管哮喘等过敏性疾病的患病率正在增加，但其原因尚不完全清楚，但人们认为环境因素而非遗传因素是主要原因。 ，部分原因是过敏与西方生活方式有关，该项目将检验呼吸道和肠道微生物群是导致过敏性疾病易感性或保护性的关键因素的假设， 传统饲养的哮喘小鼠模型将用于检验免疫系统识别的细菌亚群负责调节哮喘易感性的假设。微生物群先前已被证明在其中发挥作用。小鼠哮喘的发病机制，但对哪些微生物负责，甚至这些微生物居住在哪里（哪个身体栖息地）知之甚少。本次拨款的第一个目标是，对来自不同供应商的具有不同微生物群的小鼠进行筛选，以确定其微生物群落。卵白蛋白致敏后会诱发气道过敏性炎症，随后进行抗原攻击，这些动物的哮喘严重程度将取决于其呼吸道和肠道微生物群的气道阻塞程度和组织炎症。通过细菌 16S rRNA 测序和 BugFACS 进行表征，BugFACS 是一种根据活细菌与免疫球蛋白 A (IgA)（免疫球蛋白 A (IgA) 产生的主要抗体）的结合来分离和鉴定活细菌的技术。我将首先通过共同饲养两种类型的小鼠来识别影响哮喘表型的候选细菌菌株 - 那些具有与严重哮喘相关的微生物群的小鼠和那些具有与轻度疾病相关的微生物群的小鼠，并应用于 16S。从肠道和呼吸道微生物群生成的 rRNA 数据集将用于将观察到的哮喘严重程度变化与笼内细菌菌株的单侧或双侧入侵相关联，然后我将移植培养的侵入性菌株。 将菌株放入无菌小鼠的呼吸道和/或肠道中，以确定这些菌株是否与哮喘严重程度存在因果关系。在第二个目标中，将一小群表型良好的 6-8 岁儿童（无论是否患有哮喘）进行研究。采样以通过 16S rRNA 测序和 BugFACS 表征其呼吸道和粪便微生物群，将从 a) 急性加重期间的代表性哮喘供体移植，b) 同一哮喘患者。 c）将代表性的健康非哮喘患者转化为无菌小鼠，然后将其特征描述为如上所述。肠道微生物群与疾病发病机制的关系，并提供一种鉴定可能具有诊断和治疗用途的细菌菌株的方法。