Wang P L, Azuma Y, Shinohara M, Ohura K
Department of Pharmacology, Osaka Dental University, 8-1 Kuzuhahanazono-cho Hirakata, Osaka, 573-1121, Japan.
Biochem Biophys Res Commun. 2000 Jul 14;273(3):1161-7. doi: 10.1006/bbrc.2000.3060.
The lipopolysaccharide (LPS) secreted by Porphyromonas gingivalis is implicated in the initiation and progression of periodontitis. Human gingival fibroblasts (HGFs) are the major constituent of gingival connective tissue. In this study, we examined the expression of Toll-like receptor 4 (TLR4) on HGFs by flow cytometric analysis, and studied the signal transduction induced by LPS stimulation of HGFs by enzyme-linked immunosorbent assay, Western blotting, and immunoprecipitation. We show that LPS binds to HGFs, and that HGFs express TLR4 and myeloid differentiation primary response gene 88 (MyD88). P. gingivalis LPS-induced interleukin (IL)-1 production in HGFs was inhibited by anti-TLR4 antibody. P. gingivalis LPS treatment of HGFs activated several intracellular proteins including protein tyrosine kinases, and upregulated the expression of IL-1 receptor-associated kinase (IRAK), nuclear factor-kappaB (NF-kappaB), and activating protein-1 (AP-1), and these events were suppressed by anti-TLR4 monoclonal antibody. Our findings suggest that the binding of P. gingivalis LPS to TLR4 on HGFs activates various second messenger systems.
牙龈卟啉单胞菌分泌的脂多糖（LPS）与牙周炎的发生和发展有关。人牙龈成纤维细胞（HGFs）是牙龈结缔组织的主要成分。在本研究中，我们通过流式细胞术分析检测了HGFs上Toll样受体4（TLR4）的表达，并通过酶联免疫吸附测定、蛋白质印迹法和免疫沉淀法研究了LPS刺激HGFs诱导的信号转导。我们发现LPS与HGFs结合，且HGFs表达TLR4和髓样分化初级反应基因88（MyD88）。抗TLR4抗体可抑制牙龈卟啉单胞菌LPS诱导的HGFs中白细胞介素（IL）-1的产生。牙龈卟啉单胞菌LPS处理HGFs可激活包括蛋白酪氨酸激酶在内的多种细胞内蛋白，并上调IL-1受体相关激酶（IRAK）、核因子-κB（NF-κB）和活化蛋白-1（AP-1）的表达，而这些事件可被抗TLR4单克隆抗体抑制。我们的研究结果表明，牙龈卟啉单胞菌LPS与HGFs上的TLR4结合可激活各种第二信使系统。
