An Intracellular Niche for Borrelia burgdorferi

伯氏疏螺旋体的细胞内生态位

• 批准号: 8300386
• 负责人: JON T SKARE
• 金额: $ 18.31万
• 依托单位: TEXAS A&M UNIVERSITY HEALTH SCIENCE CTR
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-03-07 至 2014-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8300386
• 关键词: Address; Affect; Animals; Antibiotics; Antibodies; Area; Arthritis; Arthropods; Bacteria; Blood Circulation; Borrelia; Borrelia burgdorferi; Cardiac; Case Study; Cells; Complement; Connective Tissue; Coupled; Data; Dermal; Disease; Endothelial Cells; Environment; Exanthema; Experimental Models; Exploratory/Developmental Grant; Fibroblasts; Fibronectins; Goals; Health; Human; Image; Immune; Immune response; In Vitro; Individual; Infection; Infectious Agent; Integrin Binding; Integrins; Interferons; Interleukin-10; Interleukin-12; Interleukin-6; Invaded; Investigation; Locales; Location; Lyme Disease; Lymphatic; Mammals; Mediating; Metric; Molecular; Morbidity - disease rate; Mus; Natural Immunity; Neurologic; Order Spirochaetales; Pathogenesis; Pathology; Patients; Public Health; Publications; Reagent; Research; Resistance; Risk; SU 6656; Serum; Site; Staging; Sterilization; Study Section; System; Testing; United States; Work; design; erythema migrans; experience; extracellular; flu; in vivo; inhibitor/antagonist; interest; killings; kinase inhibitor; novel; novel strategies; pathogen; prevent; response; src-Family Kinases; trafficking; uptake

DESCRIPTION (provided by applicant): Lyme disease, caused by the spirochetal bacterium Borrelia burgdorferi, is the leading arthropodborne infection in the United States and causes significant morbidity in endemic areas. If untreated B. burgdorferi can persistently infect individuals even though the host mounts a potent adaptive immune response such that antibodies obtained from infected patients or experimentally infected animals effectively kills in vitro cultivated B. burgdorferi. In addition, a robust cell-mediated proinflammatory response is observed that induces IL-6, IL-12 and IFN-??and inhibits IL-10. Furthermore, the spirochete can resist complement killing demonstrating that this important component of the innate immune response is not sufficient to eliminate B. burgdorferi infection. The observation that B. burgdorferi persists in such a hostile environment indicates that the spirochete is adept at evading the host immune response via mechanisms that have not been completely elucidated. One possibility is that B. burgdorferi invades host cells and survives at low levels. Recently we have determined that B. burgdorferi invade both immortalized and, more importantly, primary cells (both fibroblasts and endothelial cells) and persist as viable cells in o-culture. In addition we have preliminary data suggesting that the ability to invade host cells involves both integrin binding and Src kinase activity. In this application we propose to further characterize the internalization of B. burgdorferi and track the fate of B. burgdorferi within thes infected cells to determine how they affect the localized host response following infection. To accomplish this we will use both in vitro correlates of invasion and intracellular survival as well as in vivo imaging of experimentally infected mice as readouts for our studies. Specifically, we propose to: (1) Characterize the invasion of Borrelia burgdorferi into primary fibroblasts. The working hypothesis here is that B. burgdorferi exploits invasion as an additional mechanism to avoid host clearance. Our preliminary studies demonstrate that B. burgdorferi invasion is not dependent on host fibronectin, but does involve ?1 integrins other than ?5?1. In this Aim we will identify the ??subunit that pairs with ?1 to promote invasion and will also evaluate how B. burgdorferi traffics within these cells; and (2) Determine if invasion is required for B. burgdorferi persistence in vivo. Our working hypothesis is that invasion contributes to persistence by providing an immunoprotected niche for B. burgdorferi. Since Src kinases are required for borrelial internalization in vitro, we will determine whether Src kinase inhibitors aler the infectivity potential of B. burgdorferi in vivo. In addition to standard cultivation and molecuar approaches, novel in vivo imaging will be employed to assess how the inhibitor affects colonization. The overall goal of these studies is to determine the extent in which an intracellula locale contributes to borrelial persistence. PUBLIC HEALTH RELEVANCE: Borrelia burgdorferi, the etiologic agent of Lyme disease, is the most common arthropod-borne infectious agent in the United States, and, as such, represents an important Public Health issue. The studies described in this application are designed to address how B. burgdorferi is able to persist effectively in infected mammals despite effective innate immune killing mechanisms and a potent adaptive immune response directed against this pathogen. The hypothesis being tested herein is that B. burgdorferi is capable of low-level intracellular survival in non-immune cells as an additional strategy to prevent borrelial host clearance.

描述（由申请人提供）：莱姆病由螺旋体细菌伯氏疏螺旋体引起，是美国主要的节肢动物感染，在流行地区引起显著的发病率。如果未经治疗，则为B。即使宿主产生有效的适应性免疫应答，使得从感染的患者或实验感染的动物获得的抗体有效地杀死体外培养的B，伯氏螺旋体也可以持续感染个体。burgdorferi。此外，观察到一个强大的细胞介导的促炎反应，诱导IL-6，IL-12和IFN-γ？并抑制IL-10。此外，螺旋体可抵抗补体杀伤，证明先天免疫应答的这一重要组分不足以消除B。伯氏感染观察到B.伯氏螺旋体能在如此恶劣的环境中存活，表明该螺旋体善于通过尚未完全阐明的机制逃避宿主的免疫反应。一种可能是B。Burgdorferi侵入宿主细胞并以低水平存活。 最近我们已经确定B.伯氏螺旋体侵袭永生化细胞，更重要的是侵袭原代细胞（成纤维细胞和内皮细胞），并在O-培养物中作为活细胞持续存在。此外，我们有初步的数据表明，入侵宿主细胞的能力涉及整合素结合和Src激酶活性。在本申请中，我们提出进一步表征B的内化。burgdorferi并追踪B的命运。感染细胞内的伯氏螺旋体，以确定它们如何影响感染后的局部宿主反应。为了实现这一点，我们将使用两个在体外相关的入侵和细胞内的生存以及 作为实验感染小鼠的体内成像，作为我们研究的读数。具体而言，我们提出：（1）表征伯氏疏螺旋体侵入原代成纤维细胞。这里的工作假设是B。burgdorferi利用入侵作为避免宿主清除的附加机制。我们的初步研究表明，B。伯氏螺旋体的侵袭不依赖于宿主纤连蛋白，但是否涉及？1、除？五个？1.在这个目标中，我们将确定？？与之配对的亚单位？1来促进入侵，并将评估如何B。burgdorferi在这些细胞内的运输;和（2）确定B是否需要入侵。Burgdorferi体内持久性。我们的工作假设是，入侵有助于持久性提供了一个免疫保护的生态位的B。burgdorferi。由于Src激酶是体外疏螺旋体内化所必需的，我们将确定Src激酶抑制剂是否能抑制B的感染潜力。Burgdorferi体内试验除了标准的培养和分子方法，新的体内成像将用于评估抑制剂如何影响定植。这些研究的总体目标是确定胞内区域有助于疏螺旋体持久性的程度。 公共卫生相关性：莱姆病的病原体伯氏疏螺旋体（Borrelia burgdorferi）是美国最常见的节肢动物传播的传染性病原体，因此代表重要的公共卫生问题。本申请中描述的研究旨在解决B。尽管存在有效的先天免疫杀伤机制和针对该病原体的有效的适应性免疫应答，但伯氏菌能够在感染的哺乳动物中有效地持续存在。本文检验的假设是B。伯氏疏螺旋体能够在非免疫细胞中低水平的细胞内存活，作为防止疏螺旋体宿主清除的额外策略。