单核细胞与牙周成纤维细胞的黏附需要激活NOD1/2和TLR4介导的LFA-1和VLA-4。
Adhesion of monocytes to periodontal fibroblasts requires activation of NOD1/2- and TLR4-mediated LFA-1 and VLA-4.
作者信息
Liu Jianru, Liu Wenyi, Xie Ying, Wang Yixiang, Ouyang Xiangying
机构信息
Department of Periodontology, Peking University School and Hospital of Stomatology, Beijing, China.
Central Laboratory, Peking University School and Hospital of Stomatology, Beijing, China.
出版信息
Arch Oral Biol. 2015 Jun;60(6):834-44. doi: 10.1016/j.archoralbio.2014.12.012. Epub 2014 Dec 23.
OBJECTIVE
The aim of this study was to investigate the roles of nucleotide-binding oligomerization domain-containing protein 1/2 (NOD1/2) and Toll-like receptor 4 (TLR4) in mediating the adhesion of monocytes to periodontal fibroblasts through leucocyte function-associated antigen-1 (LFA-1) and very late antigen-4 (VLA-4).
DESIGN
The expression of NOD1, NOD2, and TLR4 was detected in the gingival tissue of patients with chronic periodontitis by immunohistochemistry. Then the adhesion of cells of human monocytic cell line U937 to human gingival fibroblasts (hGFs) and human periodontal ligament cells (hPDLCs) was investigated after U937 cells were treated with the agonists of NOD1, NOD2, and TLR4 for 24 h, or transfected with small interfering RNAs (siRNAs) targeting NOD1, NOD2, and TLR4 for 48 h. Meanwhile, the expression of LFA-1 and VLA-4 was examined in U937 cells through real-time polymerase chain reaction (PCR), Western blot, and flow cytometry. To confirm the roles of LFA-1 and VLA-4 involved in the process of adhesion, the adhesion blockade assay was performed using the corresponding blocking antibodies against these adhesion molecules.
RESULTS
The immunostaining results showed that NOD1, NOD2, and TLR4 were highly expressed in the gingival tissue of patients with periodontitis, especially in the monocyte-infiltrated area. The activation of these receptors by agonists upregulated the expression of LFA-1 and VLA-4 in U937 cells, and it increased the affinity of U937 cells to hGFs or hPDLCs. On the other hand, knockdown of these receptors by specific siRNAs resulted in the opposite results. In addition, blocking either LFA-1 or VLA-4 in U937 cells significantly attenuated the agonist-triggered adhesion of U937 to periodontal fibroblasts (P<0.001).
CONCLUSIONS
These results suggested that NOD1/2 and TLR4 mediated monocyte-periodontal fibroblast adhesion via the modulation of LFA-1 and VLA-4.
目的
本研究旨在探讨含核苷酸结合寡聚化结构域蛋白1/2（NOD1/2）和Toll样受体4（TLR4）通过白细胞功能相关抗原-1（LFA-1）和极迟抗原-4（VLA-4）介导单核细胞与牙周成纤维细胞黏附的作用。
设计
采用免疫组织化学法检测慢性牙周炎患者牙龈组织中NOD1、NOD2和TLR4的表达。然后，将人单核细胞系U937细胞用NOD1、NOD2和TLR4激动剂处理24小时，或用靶向NOD1、NOD2和TLR4的小干扰RNA（siRNA）转染48小时后，研究其与人牙龈成纤维细胞（hGFs）和人牙周膜细胞（hPDLCs）的黏附情况。同时，通过实时聚合酶链反应（PCR）、蛋白质印迹法和流式细胞术检测U937细胞中LFA-1和VLA-4的表达。为证实LFA-1和VLA-4在黏附过程中的作用，使用针对这些黏附分子的相应阻断抗体进行黏附阻断试验。
结果
免疫染色结果显示，NOD1、NOD2和TLR4在牙周炎患者牙龈组织中高表达，尤其在单核细胞浸润区域。激动剂激活这些受体上调了U937细胞中LFA-1和VLA-4的表达，并增加了U937细胞与hGFs或hPDLCs的亲和力。另一方面，用特异性siRNA敲低这些受体则产生相反的结果。此外，阻断U937细胞中的LFA-1或VLA-4可显著减弱激动剂触发的U937与牙周成纤维细胞的黏附（P<0.001）。
结论
这些结果表明，NOD1/2和TLR4通过调节LFA-1和VLA-4介导单核细胞与牙周成纤维细胞的黏附。
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