THE STUDY ON THE MECHANISM OF CHRONIC INFLAMMATION BY THE ANALYSIS OF THE CELL FUNCTION MODIFICATION EFFECTS OF PROTEINASES FROM A PERIODONTAL DISEASE BACTERIUM

牙周病是一种主要由牙龈卟啉单胞菌感染引起的慢性炎症。该细菌产生的类胰酶半胱氨酸蛋白酶(牙龈痛；HRgpA、RgpB和Kgp)是主要的毒力因子，可能与细菌存活和牙周组织破坏有关。因此，牙龈痛通过调节细胞功能对宿主防御系统和组织破坏的影响。姜黄素对人T淋巴细胞表面CD_4、CD_8的破坏作用为0.1μM，作用30分钟。他们还分解了牙龈成纤维细胞CD14，CD14识别内毒素并激活细胞，减弱了中性粒细胞趋化因子IL-8的释放。这些结果表明，牙龈痛裂解宿主免疫细胞的受体，促进细菌从这些细胞中逃逸。牙周炎患者牙周组织基质金属蛋白酶-1、-2、-9的表达增加。因此，我们研究了牙龈痛对体外培养的牙龈细胞产生基质金属蛋白酶的影响。加入1nmHRgpA或RgpB后，牙龈成纤维细胞产生的基质金属蛋白酶-1分别增加2.5倍和2倍。中性粒细胞分别通过HRgpA和RgpB释放7倍和1.3倍以上的基质金属蛋白酶-1。0.1 nM RgpB或1 nM HRgpA可使牙龈上皮细胞产生的基质金属蛋白酶-2增加5倍。综上所述，牙龈痛R刺激牙龈细胞和中性粒细胞产生基质金属蛋白酶，从而促进牙龈组织的破坏。凝血因子Xa特异性抑制剂DX9065a抑制牙周炎患者牙周组织中牙周炎的活性，提示其可能具有治疗牙周炎的作用。

The periodontal disease is a chronic inflammation caused mainly by Porphyromonas gingivalis infection. The trypsin-like cysteine proteinases produced from the bacterium (gingipains; HRgpA, RgpB and Kgp) are major virulence factors and may be associated the bacterial survival and periodontal tissue breakdown. Hence, the effects of gingipains on the host-defense system and tissue destruction through modulating cell functions. Gingipains destroyed CD4 and CD8 on the human T lymphocytes at 0.1 μM in 30 min. They also cleaved off gingival fibroblast CD14, which recognizes LPS and activates the cells, attenuating the release of IL-8, a neutrophil chemotactic factor. These results indicated that gingipains cleaves receptors of host immune cells, facilitating the escape of the bacterium from these cells. The gingival tissue with periodontitis increased expression matrix metalloproteinase (MMP)-1, -2 and -9. Therefore, the effect of gingipains on cultured gingival cell MMP production was investigated. Gingival fibroblast MMP-1 production increased 2.5 and 2-fold by addition of 1nM HRgpA or RgpB, respectively. Neutrophils released 7 or 1.3-fold more MMP-1 by HRgpA or RgpB, respectively. MMP-2 production by gingival epithelial cells increased 5-fold by 0.1 nM RgpB or 1 nM HRgpA. Taken together, gingipains R stimulate MMP production by gingival cells and neutrophils, which promotes gingival tissue destruction. The fact that factor Xa-specific inhibitor, DX9065a inhibited these gingipain R activities suggested a possible therapeutic effect of proteinase inhibitors on periodontitis.