Genetic and Functional Traits of Cultivated Nasal Bacteria in Relapsing Granulomatosis with Polyangiitis

项目概要/摘要 肉芽肿病伴多血管炎是一种以肉芽肿性炎症为特征的系统性血管炎 而且经常复发鼻窦炎是GPA的一个显著特征，与更高的风险相关。 复发虽然我们对GPA的免疫发病机制的了解已经取得了进展，但对GPA的免疫机制知之甚少。 疾病活动的触发因素。特别是，有两个问题仍然没有答案：1）是什么点燃了疾病活动， 平均绩点？2)为什么尽管临床表现和免疫抑制治疗相似， 比其他人更容易复发机制和流行病学研究表明，微生物，特别是 鼻微生物群可能是GPA的重要环境激活剂。为了加深我们对 鼻微生物组对GPA疾病活动的潜在影响，我们的研究小组使用了高通量 测序方法，以全面调查鼻腔中的数千种常驻微生物群， GPA患者我们使用16S基因测序的初步发现显示了鼻粘膜的动态变化， 在GPA复发发作之前，微生物组，相反，静止期患者的时间稳定性 疾病对16S基因进行测序是表征微生物组的合适的初始方法， 在物种/菌株分辨率（最多识别属水平）和确定功能信息方面受到限制。在 为了研究鼻细菌之间的种属和菌株特异性相互作用的假设， 激活GPA患者鼻腔黏膜免疫反应，首先需要：1）增加 鉴定与GPA复发相关的细菌物种/菌株的分类学解析，2）证明 培养感兴趣的细菌用于未来机理研究的可行性，以及3）评估是否 微生物遗传途径（例如，代谢物或毒力相关基因）与GPA复发相关。 拟议研究的目的是鉴定、培养和功能表征细菌菌种 以及与GPA患者的疾病活动相关的菌株。超越分类鉴定 (what微生物存在），了解功能成分（微生物可以做什么）可以 发现微生物激发或维持自身免疫的机制。这项工作将直接导致 对鼻内细菌激活宿主免疫力的机制进行了更深入的研究。理解 影响宿主生理学和介导跨物种关系的关键遗传和功能性状可能 导致开发针对微生物或其产物以及早期肿瘤生物标志物的新疗法。 GPA中的疾病检测

PROJECT SUMMARY/ABSTRACT Granulomatosis with polyangiitis (GPA) is a systemic vasculitis characterized by granulomatous inflammation and frequent relapses. Rhinosinusitis is a distinguishing feature of GPA and associated with a higher risk of relapse. While our knowledge of the immunopathogenesis of GPA has advanced, little is known about the triggers of disease activity. In particular, two questions remain unanswered: 1) what ignites disease activity in GPA? 2) why, despite similarities in clinical presentation and immunosuppressive therapy, are some patients more likely to relapse than others? Mechanistic and epidemiologic studies suggest microbes, in particular nasal microbiota, may be an important environmental activator of GPA. To deepen our understanding of the potential effects of the nasal microbiome on disease activity in GPA, our group used high-throughput sequencing methods to comprehensively investigate the thousands of resident microbiota in the nasal cavity of patients with GPA. Our preliminary findings using 16S gene sequencing showed dynamic changes in the nasal microbiome prior to the onset of relapse in GPA and, conversely, temporal stability in those with quiescent disease. Sequencing the 16S gene was an appropriate initial approach to characterize the microbiome but is limited in species/strain resolution (identifies genus level at best) and ascertaining functional information. In order to investigate the hypothesis that species- and strain-specific interactions between nasal bacteria activate the mucosal immune response in the nasal cavity of patients with GPA, we first need to: 1) increase taxonomic resolution to identify species/strains of bacteria associated with GPA relapse, 2) demonstrate feasibility of culturing bacteria of interest for use in future mechanistic studies, and 3) evaluate whether microbial genetic pathways (e.g., metabolites or virulence-related genes) are associated with relapse in GPA. The objective of the proposed study is to identify, culture, and functionally characterize the bacterial species and strains that are associated with disease activity in patients with GPA. Beyond taxonomic identification (what microbes are present), understanding the functional composition (what can the microbes do) may discover the mechanisms in which microbes incite or perpetuate autoimmunity. This work will directly lead to deeper investigations into the mechanisms used by nasal bacteria to activate host immunity. Understanding the key genetic and functional traits that affect host physiology and mediate cross-species relationships may lead to the development of novel therapies targeting microbes or their products as well as biomarkers of early disease detection in GPA.