Identification of linear plasmid lp36-encoded virulence determinants in the Lyme disease spirochete Borrelia burgdorferi

项目摘要/摘要 莱姆病是由壁虱传播的伯氏疏螺旋体感染引起的，可导致 影响关节、心脏和神经系统的炎性病理。由于没有疫苗或有效 媒介控制感染，莱姆病是并将继续是一个重要的公共卫生问题 担忧。这项提案直接涉及美国国立卫生研究院壁虱传播疾病研究战略计划， 对了解基本生物学和宿主与其相互作用的具体应用 扁虱传播的病原体。这些研究的总体目标是确定伯氏假单胞菌的候选目标 莱姆病的预防和治疗。 伯氏杆菌分离株表现出高度的遗传异质性，某些基因类型与 增加了人类的致病机制。据报道，高致病力的基因型会诱导出更强的 宿主细胞的I型干扰素反应，阻断I型干扰素在实验室消除病理 莱姆病的小鼠模型；强调I型干扰素在莱姆病发病机制中的重要性 疾病。 尽管干扰素信号在莱姆病的发病机制中很重要，但细菌因素 参与刺激干扰素的产生还不是很清楚。最近，B。 伯氏杆菌线性质粒lp36与宿主产生的I型和III型干扰素相关 细胞外，然而，涉及的特定基因和哺乳动物感染期间的后果没有 已经确定了。 我们假设lp36编码未知的毒力决定因素，所需刺激生产。 来自宿主细胞的干扰素，以及在哺乳动物感染期间诱导疾病病理。通过有选择地 删除伯氏杆菌中lp36的不同区域，我们的研究将解决以下目标：(1)定义 先天免疫细胞反应所需的lp36基因；以及(2)确定lp36基因对 哺乳动物感染过程中细菌的定植和病理诱导。 我们的创新的线性质粒截断方法允许筛选大的质粒区 存在新的毒力因子。使用不同大小的系统截断，我们希望确定 参与刺激宿主细胞产生干扰素的Lp36基因，并确定它们在 感染过程中病原体的适合性和组织病理学。这项工作将推动莱姆病研究领域的发展 因此，这些因素是新的预防和治疗方法的理想候选靶点。 伯氏杆菌感染和相关的免疫病理学。

PROJECT SUMMARY/ABSTRACT Lyme disease, which is caused by infection with the tick-borne pathogen Borrelia burgdorferi, can lead to inflammatory pathologies affecting the joints, heart, and nervous systems. As there are no vaccines or effective vector controls against the infection, Lyme disease is and will continue to be a significant public health concern. This proposal directly addresses the NIH Strategic Plan for Tickborne Disease Research, with specific applications towards understanding the fundamental biology of, and the host interactions with tickborne pathogens. The overall goal of these studies is to identify candidate B. burgdorferi targets for prophylactic and therapeutic treatments for Lyme disease. Isolates of B. burgdorferi display a high level of genetic heterogeneity, and certain genotypes correlate with increased pathogenesis in humans. High pathogenicity genotypes have been reported to induce a more robust Type I interferon response from host cells, and blocking Type I interferon abrogates pathology in laboratory mouse models of Lyme disease; underscoring the importance of Type I interferon in the pathogenesis of Lyme disease. Despite the importance of interferon signaling in the pathogenesis of Lyme disease, the bacterial factors involved in stimulating production of interferon are not well understood. Recently, the presence of the B. burgdorferi linear plasmid lp36 was shown to correlate with Type I and Type III interferon production from host cells ex vivo, however the specific genes involved and the consequences during mammalian infection have not been determined. We hypothesize that lp36 encodes unidentified virulence determinants required for stimulating production of interferon from host cells, as well as induction of disease pathology during mammalian infection. By selectively deleting different regions of lp36 in B. burgdorferi, we will address the following aims in our studies: (1) Define the lp36 genes required for innate immune cell responses; and (2) Determine the requirement of lp36 genes for bacterial colonization and induction of pathology during mammalian infection. Our innovative approach of linear plasmid truncation allows for screening large plasmid regions for the presence of novel virulence factors. Using systematic truncations of different sizes, we expect to identify the lp36 genes involved in stimulation of interferon production from host cells, and determine their roles in pathogen fitness and tissue pathology during infection. This work will move the field of Lyme disease research forward, as such factors are ideal candidate targets for novel prophylactic and therapeutic treatments for B. burgdorferi infection and associated immunopathologies.