Examination of biological response to Porphyromonas gingivalis infection.

牙龈卟啉单胞菌是成人牙周炎的主要病原体，它能产生一类独特的毒力蛋白，称为精氨酸牙周疼痛(RGPS)和赖氨酸牙周疼痛(KGP)。我们纯化了一个660 kDa的细胞相关牙龈痛复合体，它作为两个催化活性单体的同源二聚体存在，包括它们的催化域和粘附素结构域。电子显微镜显示，该络合物由外径为10 nm的球形颗粒组成，具有一个或两个电子致密的空穴状结构。双向凝胶电泳和免疫印迹分析表明，该复合体含有脂多糖(LPS)。该复合体显著降解人I型胶原和弹性蛋白，并强烈干扰人牙龈成纤维细胞和内皮细胞的细胞活力，与单体牙龈痛相比，其效率更高。天然复合体几乎不诱导产生二氧化氮、肿瘤坏死因子α和白介素6β…。更多的巨噬细胞，而热变性的复合体导致它们的产生增加。这些结果表明，该复合体在逃避寄主防御机制以及在寄主组织破坏中具有重要作用。许多流行病学研究表明，牙周感染是动脉粥样硬化的危险因素。反复静脉注射野生型牙龈假单胞菌可导致高脂饮食喂养的载脂蛋白E基因敲除小鼠动脉粥样硬化病变面积增加，血清低密度脂蛋白胆固醇浓度升高，高密度脂蛋白胆固醇浓度降低。然而，RGP/KGP缺陷的牙龈假单胞菌并没有促进动脉粥样硬化的发生。Rgp特异性抑制剂可抑制Pgp野生型对动脉粥样硬化病变的促进作用。因此，RGP的蛋白分解活性在牙龈假单胞菌感染促进动脉粥样硬化中起着至关重要的作用。较少

Porphyromonas gingivalis is the primary pathogenic agent of adult periodontitis and produces a unique class of virulence proteinases known as Arg-gingipains (Rgps) and Lys-gingipain (Kgp). We purified a 660-kDa cell-associated gingipain complex existing as a homodimer of two catalytically active monomers that comprises their catalytic and adhesin domains. Electron microscopy revealed that the complex was composed of a globular particle with 10-nm external diameter possessing one or two electron dense hole-like structures. Two-dimensional gel electrophoresis and immunoblot analyses revealed the complex includes lipopolysaccharide (LPS). The complex significantly degraded human type I collagen and elastin and strongly disrupted cell viability of human gingival fibroblasts and endotherial cells with higher efficiencies compared to the monomeric gingipains. The native complex little induced production of nitrogen dioxide (NO_2), tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6) b … More y macrophages, whereas the heat-denatured complex resulted in increased production of them. The results indicate the importance of the complex in evasion of host defense mechanisms as well as in host tissue breakdown. Many epidemiological studies suggest that periodontal infections are a risk factor for atherosclerosis. Repeated intravenous injection of wild-type P.gingivalis resulted in an increase in the area of atherosclerotic lesions as well as an increase in the serum concentration of low-density lipoprotein (LDL) cholesterol and a decrease in that of high-density lipoprotein (HDL) cholesterol in apolipoprotein (apo) E-knockout mice fed a high-fat diet. However, Rgp/Kgp-deficient P.gingivalis did not promoted the atherosclerotic lesions. The specific inhibitors against Rgp suppressed the promotion of atherosclerotic lesions induced by wild-type P.gingivalis. Proteolytic activity of Rgp thus appears to play a crucial role in the promotion of atherosclerosis by P.gingivalis infection. Less