Molecular Patterns of Borrelia - Chemical Structure and Innate Immune Responses involving LPS Binding Protein (LBP)

本研究的目的是明确从螺旋体（包括密螺旋体、疏螺旋体和钩端螺旋体）外膜分离的糖脂诱导先天免疫反应的分子机制。在化学表征之后，我们将通过toll样受体（TLRs）对细胞宿主反应进行结构-功能分析。确定生物活性所需的螺旋体糖脂的结构要素，将导致确定细菌化合物的分子模式，这些分子模式对于刺激一般的先天免疫反应至关重要。在之前的工作中，我们分离了两株密螺旋体菌株的外膜糖脂，化学分析发现其结构与革兰氏阳性菌的脂质胆酸（LTA）密切相关。这些化合物通过脂多糖（LPS）结合蛋白（LBP）、CD14和TLRs诱导单核细胞释放细胞因子。基于这些发现，拟议的项目将这项工作扩展到临床高度相关的螺旋体，包括伯氏疏螺旋体。化学分析将与Borstel研究中心密切合作，然后使用我们实验室建立的转染不同tlr的细胞系进行刺激实验。这将通过tlr缺陷小鼠的研究，以及tlr多态性在莱姆病中的作用的临床研究来完成。确定先天免疫反应所需的分子模式可能有助于开发由螺旋体和其他细菌引起的感染的新的预防和干预策略。

The object of this study is to define the molecular mechanisms of the induction of innate immune responses induced by glycolipids isolated from the outer membrane of spirochetes including Treponema, Borrelia and Leptospira. Following chemical characterization, we will perform structure-function analysis of cellular host responses via Toll-like receptors (TLRs). Defining structural elements of spirochetal glycolipids required for biological activity should lead to the definition of molecular patterns of bacterial compounds essential for stimulation of innate immune responses in general. In previous work, we isolated glycolipids of the outer membrane of two treponeme strains, and chemical analysis revealed a structure closely related to Lipoteichoic acid (LTA) of Gram-positive bacteria. These compounds induced cytokine release in mono- nuclear cells depending on Lipopolysccharide (LPS) binding protein (LBP), CD14 and TLRs. Based on these findings, the proposed project extends this work to clinically highly relevant spirochetes including B. burgdorferi. Chemical analysis will be performed in close collaboration with the Borstel Research Center followed by stimulation experiments using cell lines transfected with different TLRs established in our lab. This will be completed by studies on TLR-deficient mice, and clinical investigations on the role of TLR-polymorphisms in Lyme disease. Defining the molecular patterns required for innate immune responses may aid in developing novel prevention and intervention strategies in infectious caused by spirochetes and other bacteria.