Functional Analyses of Borrelia burgdorferi Adhesins

 描述（由申请人提供）：莱姆病螺旋体经病媒蜱传播后，可造成局部皮肤感染，然后可进一步传播至多个组织。 与哺乳动物细胞和细胞外基质（ECM）的相互作用对于不同位点的定殖至关重要，并且许多B.已经鉴定了与细胞或细胞外基质（ECM）结合的伯氏菌粘附素。大量的粘附素，以及一些序列的变异性，可能会促进慢性多系统疾病，并有助于人类莱姆病的多样性。靶组织的多样性、粘附素的多功能性和定植的复杂性（例如血流存活， 血管粘附、组织侵入和逃避免疫监视）。为了将过多的受体-配体相互作用组织成一个框架，以了解莱姆病的多系统性质，三位合作者采取了多方面的遗传，生化和成像方法来充分表征已知的B。Burgdorferi粘附素，以发现和验证新的粘附素，并探索B的全部功能。使用体外和体内模型的Burgdorferi粘附素。这些方法导致了对已知粘附素DbpA，BBK 32和P66的重要新见解，并为OspF亚家族和OspC定义了新的粘附功能，这在以前被证明是完全感染性所必需的。我们发现DbpA和OspC变体与不同的组织向性相关，因此粘附素库中的菌株特异性差异可能导致临床表现的相应差异。我们发现，BBK 32和P66在血管粘附和关节侵袭中发挥作用，它们介导的与血管内皮的相互作用可能反映了与淋巴细胞迁移类似的连续活动。我们假设B. Burgdorferi利用多种具有不同活性的粘附素来协调多相和多系统感染中的连续步骤。此外，粘附素亚组的序列变异可能促进不同位点的定殖，并导致组织嗜性和疾病的菌株特异性差异。详细了解B的复杂库如何介导多种宿主细胞相互作用。由于burgdorferi粘附素协调血管附着、组织侵袭和多种组织的长期定殖，我们将使用B的力量。burgdorferi遗传系统和不同的小鼠感染模型。我们将扩展并充分刻画B。本发明涉及促进与内皮相互作用的伯氏（burgdorferi）粘附素，以确定小鼠组织的传播和长期定殖所需的粘附素-配体相互作用。我们还将描述这些相互作用中的每一种在促进附着到血管内皮所需的多个步骤中的作用，以穿过该屏障稳定地定殖组织。拟议的工作将组织复杂的粘附途径到功能组，介导离散的步骤，在感染过程中，共同导致系统性莱姆病疏螺旋体病和扩散，持续感染的小鼠。

 DESCRIPTION (provided by applicant): Upon transmission by a vector tick, Lyme disease spirochetes can establish a local skin infection, then may disseminate further to multiple tissues. Interactions with mammalian cells and extracellular matrix (ECM) are critical for colonization of diverse sites, and many B. burgdorferi adhesins that bind to cells or extracellular matrix (ECM) have been identified. The large number of adhesins, as well as the sequence variability of some, is likely to promote chronic multisystem disease and contribute to the noted diversity of human Lyme disease. Understanding this infection is complicated by the diversity of target tissues, multifunctionality of adhesins, and complexity of colonization (e.g. bloodstream survival, vascular adherence, tissue invasion, and escape from immune surveillance). To organize the plethora of receptor-ligand interactions into a framework for understanding the multisystem nature of Lyme disease, the three collaborators have taken multi-faceted genetic, biochemical and imaging approaches to fully characterize known B. burgdorferi adhesins, to discover and validate new adhesins, and to probe the functions of the full repertoire of B. burgdorferi adhesins using in vitro and in vivo models. These approaches led to important new insights into the known adhesins DbpA, BBK32, and P66, and defined new adhesive functions for the OspF subfamily and for OspC, which was previously shown to be essential for full infectivity. We showed that DbpA and OspC variants are associated with different tissue tropisms, so strain-specific differences in the repertoire of adhesins may contribute to corresponding differences in clinical manifestations. We found that BBK32 and P66 have roles in vascular adherence and joint invasion, and the interactions they mediate with the vascular endothelium may reflect sequential activities analogous to those involved in lymphocyte transmigration. We hypothesize that B. burgdorferi utilizes a multitude of adhesins with distinct activities to negotiate successie steps in a multiphasic and multisystem infection. In addition, sequence variation of a subset of adhesins may promote colonization of distinct sites and contribute to strain-specific differences in tissue tropism and disease. To gain a detailed understanding of how the diverse host cell interactions mediated by the complex repertoire of B. burgdorferi adhesins coordinate vascular attachment, tissue invasion and long-term colonization of diverse tissues, we will use the power of B. burgdorferi genetic systems and diverse mouse infection models. We will expand and fully characterize B. burgdorferi adhesins that promote interactions with endothelium to define the adhesin-ligand interactions that are required for dissemination and long-term colonization of mouse tissues. We will also characterize the role of each of these interactions in promoting the multiple steps required to attach to the vascular endothelium, to transmigrate across this barrier to stably colonize tissue. The proposed work will organize complex adhesive pathways into functional groups that mediate discrete steps in the infectious processes that together result in systemic Lyme borreliosis and disseminated, persistent infection in the mouse.