Macrophage response to LPS in periodontal disease

目前的概念表明，单核/巨噬细胞对细菌内毒素刺激的反应至少在一定程度上参与了牙周病的进展和严重程度。特别是，促炎细胞因子，如IL-1β和TNFα，以及其他炎症介质(PGE2)的产生增加，似乎会导致依恋丧失的进展。在糖尿病患者中，内源性或结构性细胞因子对脂多糖的反应已被报道高于正常水平。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。巨噬细胞上的主要内毒素结合蛋白是CD14。已知巨噬细胞对内毒素的细胞因子反应部分是由CD14介导的，尽管使用抗CD14抗体的抑制实验表明只有部分阻断。此外，CD14是一种糖基化磷脂酰肌醇(GPI)锚定蛋白，没有信号穿过细胞膜。根据实验确定Toll样受体(TLR)蛋白，特别是TRL4是脂多糖结合蛋白，并且脂多糖与moesin结合可以诱导IL-1和TNF的产生，从而推测了第二类内毒素受体。抗Moesin抗体完全阻断CD14介导的内毒素反应，部分参与CD14结合事件的信号转导。我们的假设是，moesin是CD14/Toll内毒素受体复合体的一个组成部分。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。由于参与这一反应的分子还没有完全确定，我们将首先研究正常细胞中的内毒素受体和辅助受体的特征，然后再继续研究糖尿病患者的细胞。因此，这一建议的具体目的是表征CD14、内毒素结合蛋白(LBP)、Toll样受体(TRL4)和moesin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.