Macrophage response to LPS in periodontal disease

目前的概念表明，单核细胞/巨噬细胞对细菌LPS刺激的反应至少部分介导了牙周病的进展和严重程度。特别是，促炎细胞因子（如IL-1 β和TNF α）和其他炎症介质（PGE 2）的产生增加似乎导致附着丧失的进展。据报道，在糖尿病患者中，对LPS的内在或组成性细胞因子应答高于正常水平。与牙周病进展相关的细胞因子反应也明显高于非糖尿病人群。巨噬细胞上的主要LPS结合蛋白是CD 14。巨噬细胞对LPS的细胞因子应答已知部分由CD 14介导，尽管使用抗CD 14抗体的抑制实验仅显示部分阻断。此外，CD 14是一种糖基磷脂酰肌醇（GPI）锚定蛋白，没有信号穿过细胞膜。基于鉴定Toll样受体（TLR）蛋白，特别是TRL 4作为LPS结合蛋白的实验，已经假设了第二类LPS受体，并且LPS与膜突蛋白的结合诱导IL-1和TNF产生。膜突蛋白抗体完全消除了CD 14介导的LPS反应，这部分地负责CD 14结合事件的信号转导。我们的假设是膜突蛋白是CD 14/Toll LPS受体复合物的组分。此外，该分子的表达和功能在糖尿病及其并发症（包括牙周炎）的发病机制中起重要作用。由于参与这种反应的分子尚未完全表征，我们将首先对正常细胞中的LPS受体和辅助受体进行表征，然后继续研究糖尿病患者的细胞。因此，本提案的具体目的是表征CD 14、LPS结合蛋白（LBP）、Toll样受体（TRL 4）和膜突蛋白之间的分子结构/功能关系。

Current concepts suggest that the monocyte/macrophage response to bacterial LPS stimulation mediates, at least in part, the progression and severity of periodontal disease. In particular, elevated production of pro- inflammatory cytokines, such as IL-1beta and TNFalpha, and other inflammatory mediators (PGE2), appears to result in progression of attachment loss. In the diabetic patient, the intrinsic or constitutive cytokine response to LPS has been reported to be elevated above normal. The cytokine response associated with progression of periodontal disease is also markedly higher than in the non-diabetic population. The major LPS binding protein on macrophages is CD14. The cytokine response in macrophages to LPS is known to be mediated in part by CD14, although inhibition experiments using anti-CD14 antibody reveal only partial blocking. In addition, CD14 is a glycosylphosphatidylinositol (GPI) anchored protein without a signal across the cell membrane. A second class of LPS receptor has been hypothesized based on experiments identifying Toll like receptor (TLR) proteins, particularly TRL4, as LPS binding proteins and LPS binding to moesin induces both IL-1 and TNF production. Antibody to moesin ablates the CD14 mediated LPS response completely which is, in part, responsible for signal transduction of CD14 binding events. Our hypotheses is that moesin is a component of the CD14 /Toll LPS receptor complex. Further, that the expression and function of this molecule plays an important role in the pathogenesis of diabetes mellitus and it's complications, including periodontitis. Since the molecules involved in this response are not fully characterized, we will first pursue the characterization of LPS receptors and co-receptors in normal cells and then proceed to cells from the diabetic patient. The Specific Aims of this proposal, therefore, are to characterize the molecular structure/function relationship between CD14, LPS binding protein (LBP), Toll-like receptors (TRL4) and moesin.