T. forsythia TLR2 ligands and surface glycans coordinate periodontal inflammation

描述（由申请人提供）：与其他牙周病原体相比，Tannerella asthia仍然是一种研究较少的神秘生物体，尽管临床证据越来越多地表明该生物体与牙周炎有关。近年来，T。在牙髓感染中也发现了牙菌斑，并与全身性疾病有关。繁殖这种细菌的困难以及它对基因操作的抵抗力使这种细菌对研究人员的吸引力降低。T.该菌表达充分表征的TLR 2配体、BspA蛋白以及N-和0-聚糖连接的糖蛋白，所述糖蛋白构成其覆盖外膜的表面（S）层。BspA蛋白和细菌聚糖在细菌毒力中起关键作用。具体而言，S-层聚糖影响抗原呈递细胞的细菌识别，并改变其细胞因子表达，从而导致Th 17应答和中性粒细胞募集的阻断。这导致宿主中的细菌持久性和定殖增加。同时，BspA和T.白喉诱导TLR 2信号传导，有利于不利于牙槽骨的Th 2型炎症反应的发展。本申请的目的是了解T.利多卡因利用其表面聚糖和TLR 2配体诱导牙槽骨丢失。为了达到这一目的，我们提出：（1）定义T的相互作用。巨噬细胞和树突状细胞的S层聚糖以及导致宿主免疫调节的机制。我们将验证表面聚糖通过与凝集素样受体相互作用来调节细胞因子反应和功能的假设;（2）确定TLR 2-Th 2轴如何对T.使用牙周炎小鼠模型研究牙周炎诱导的牙槽骨丢失。我们将检验Th 2极化触发增殖的假设 表达RANKL的B细胞，最终导致牙槽骨丢失。因此，我们的研究将详细描述TLR 2通过细菌配体和S层糖蛋白的连接在T.牙周炎是牙周炎的主要发病机制之一，它是牙周炎预防策略的基础。

DESCRIPTION (provided by applicant): Tannerella forsythia remains a less studied and an enigmatic organism in comparison to other periodontal pathogens, even though clinical evidence increasingly implicates the organism in periodontitis. Additionally, in recent years T. forsythia has also been detected in endodontic infections and linked to systemic diseases. Difficulties in propagating this bacterium and the fact that it is quite resistant to genetic manipulations have made this bacterium less appealing to investigators. T. forsythia expresses a well- characterized TLR2 ligand, the BspA protein, and N- and O-glycan linked glycoproteins that comprise its surface (S) - layer, covering the outer membrane. The BspA protein and the bacterial glycans play critical roles in bacterial virulence. Specifically, S-layer glycans impact bacterial recognition by the antigen-presenting cells and modify their cytokine expression such that it results in the blockade of Th17 responses and neutrophil recruitment. This leads to increased bacterial persistence and colonization in the host. Concurrently, BspA and other ligands of T. forsythia induce TLR2 signaling favoring the development of Th2-type inflammatory responses detrimental to the alveolar bone. The aim of this application is to understand the mechanisms by which T. forsythia exploits its surface glycans and TLR2 ligands to induce alveolar bone loss. To achieve our aim we propose to: (1) Define the interactions of T. forsythia S-layer glycans with macrophages and dendritic cells and the mechanisms leading to host immune modulation. We will test the hypothesis that the surface glycans by interacting with lectin-like receptors regulate cytokine responses and function of these cells, and; (2) Determine how theTLR2-Th2 axis contributes to T. forsythia-induced alveolar bone loss using a periodontitis mouse model. We will test the hypothesis that Th2 polarization triggers proliferation of RANKL expressing B cells, which eventually contributes to alveolar bone loss. Thus, our studies will delineate in detail the underlying mechanisms by which TLR2 ligation by bacterial ligands and S-layer glycoproteins orchestrate host immunity during T. forsythia-induced periodontal inflammation and will be fundamental to the development of preventive strategies against periodontitis in the future.