Immune regulation of oral mucosa and oral mucosal diseases by proteases and their inhibitors

本课题的研究成果如下：1。牙周病细菌产生的胰蛋白酶样蛋白酶通过蛋白酶激活受体（PAR） 1和PAR2激活人牙龈成纤维细胞，表明该蛋白酶在牙周病的发病中起重要作用。抗gr -1注射（中性粒细胞耗竭）可显著降低痤疮丙酸杆菌引物小鼠血清白细胞介素18 （IL-18）水平和IL-18依赖性肝损伤。丝氨酸蛋白酶抑制剂与LPS共给药也观察到同样的结果。小鼠PAR2缺乏显著损害了痤疮P.和LPS对IL-18的诱导，并且在痤疮P.和LPS处理的PAR2^<-/->小鼠中，肝脏组织仅发生轻微的病理改变。这些结果表明，中性粒细胞募集和中性粒细胞丝氨酸蛋白酶激活PAR2在诱导IL-18.3的过程中起关键作用。乳铁蛋白（Lf）是一种铁结合蛋白，存在于大多数外分泌分泌物中，如唾液。在这项研究中，我们在慢性牙周炎患者的唾液中发现了小的Lf肽，并证实它们是完整的Lf片段。在牙周炎患者唾液中检测到蛋白酶3 （PR3）蛋白，PR3活性及Lf片段水平与临床症状严重程度相关。唾液Lf肽对埃希氏菌无抑菌活性；铁螯合能力也降低了。唾液Lf肽诱导人口腔上皮细胞产生促炎细胞因子。这些结果表明，牙周炎患者腮腺唾液中的Lf通过pr3样活性降解为小肽，具有诱导炎症介质的能力。我们在唾液中鉴定了toll样受体2 （TLR2）的可溶性形式。由于TLR2最初是一种跨膜受体，因此一些蛋白酶参与了可溶性TLR2的生成。我们发现唾液可调节tlr2介导的口腔免疫反应

Research results of this project are as follows,1. Trypsin-like protease produced by periodontopathic bacteria activated human gingival fibroblasts through protease activated receptor (PAR) 1 and PAR2, suggesting that this protease is critically involved in onset of periodontal disease.2. Serum interleukin 18 (IL-18) levels and IL-18-dependent liver injury induced by LPS in Propionibacterium acnes-primed mice were significantly reduced by anti-Gr-1 injection (depletion of neutrophils). The same results were observed by co-administration of a serine protease inhibitor with LPS. A deficiency of PAR2 in mice significantly impaired IL-18 induction by treatment with P. acnes and LPS, and only slight pathological changes in hepatic tissues occurred in the PAR2^<-/-> mice treated with P. acnes and LPS. These results indicate that neutrophil recruitment and PAR2 activation by neutrophil serine proteases are critically involved in the induction of IL-18.3. Lactoferrin (Lf) is an iron-binding an … More tibacterial protein, present in most exocrine secretions, such as saliva. In this study, we identified small Lf peptides in the saliva of chronic periodontitis patients and confirmed them to be fragments of intact Lf. Proteinase 3 (PR3) protein was detected in the saliva of periodontitis patients, and PR3 activity and levels of Lf fragments were correlation to the severity of clinical symptoms. Saliva Lf peptides showed no anti-bacterial activity against Escherichia coil; and had a reduced iron-chelating capacity. Saliva Lf peptides induce the production of pro-inflammatory cytokines in human oral epithelial cells. These results suggest that Lf in the parotid saliva of periodontitis patients was degraded into small peptides by the PR3-like activity with the capability to induce inflammatory mediators.4. We identified soluble form of Toll-like receptor 2 (TLR2) in saliva. As TLR2 is an originally transmembrane receptor, it is suggested that some proteases are involved in the generation of soluble TLR2. We found that saliva modulated the TLR2-mediated immune responses in oral cavity Less