牙龈卟啉单胞菌红细胞凝集素A黏附和入侵人牙龈上皮细胞的研究

目的:检测牙龈卟啉单胞菌(Porphyromonas gingivalis,P.g)膜表面红细胞凝集素A(hemagglutinin A,HagA)黏附和入侵人牙龈上皮细胞的功能。方法:构建P.g381hagA基因的变异菌株,连接hagA基因到pYA292质粒上,并克隆到无毒性的沙门杆菌x4072菌中,通过比较变异菌株、野生菌株和表达hagA基因的沙门杆菌对人牙龈上皮细胞的黏附和入侵功能,检测HagA在此过程中的作用。结果:P.g381hagA基因变异菌株和野生菌株在对细胞的黏附和入侵过程中没有显著差别,但沙门杆菌x4072HagA表达菌株对细胞的黏附性和入侵性比对照组分别提高了3倍和4倍。结论:HagA参与了P.g381黏附和入侵牙龈上皮细胞的过程。     

牙龈卟啉单胞菌侵入牙龈上皮细胞的分子机制

牙龈卟啉单胞菌是慢性牙周炎的主要致病菌,牙龈上皮细胞是宿主牙周组织防御机制的第一道天然屏障。牙龈卟啉单胞菌可通过特异性粘附素与牙龈上皮细胞相应配体结合,激活该细胞内多种信号传导途径,最终内化于牙龈上皮细胞。内化后可通过某些细胞因子的合成和分泌减少以及抑制细胞凋亡等机制造成该细胞功能紊乱。本文从分子水平对牙龈卟啉单胞菌侵入牙龈上皮细胞的机制作一综述,以进一步阐明牙龈卟啉单胞菌的致病机理。     

牙龈卟啉单胞菌感染对血管内皮细胞与单核细胞黏附的影响

目的：研究Pg感染对人脐静脉内皮细胞（HUVEC）与单核细胞黏附的影响。方法：建立Pg感染HUVEC细胞株EA．hy926的体外模型,虎红染色法观察Pg381和Pg33277菌株感染HUVEC 6 h和24 h后,HUVEC与人单核细胞株THP-1细胞黏附量的变化。结果：培养6 h时Pg381感染组的THP-1细胞黏附量相对值为0．210±0．025,高于Pg33277感染组（0．078±0．024,P＜0．05）和空白对照组（0．062±0．022,P＜0．05）,Pg33277感染组和空白对照组无差异。24 h时3组间无差异（P＞0．05）。结论：Pg381感染HUVEC后能显著促进其与单核细胞的黏附。     

牙龈卟啉单胞菌膜泡对牙龈上皮细胞MMPs基因表达的影响

目的:探讨牙龈卟啉单胞菌膜泡对牙龈上皮细胞基质金属蛋白酶(MMPs)基因表达的影响,揭示牙龈卟啉单胞菌在牙周炎中的致病作用.方法:以Real-time RT-PCR法检测牙龈卟啉单胞菌膜泡刺激下牙龈上皮细胞MMP-1和MMP-3的mRNA表达水平.结果:牙龈卟啉单胞菌膜泡显著地上调MMP-1和MMP-3 mRNA表达水平.结论:牙龈卟啉单胞菌诱导牙龈上皮细胞发生细胞炎症反应,可能是牙周炎发生、发展的重要因素.     

黏性放线菌和牙龈卟啉单胞菌间共聚对黏性放线菌黏附于S-HA的影响

目的:研究黏性放线菌(A.viscosus)和牙龈卟啉单胞菌(P.gingivalis)间共聚对A.viscosus黏附于唾液包被的羟基磷灰石(S-HA)的影响.方法:将0.5mL 5×108CFU/mL A.viscosus分别与0.5mL 1×109、3×109、5×109CFU/mL的P.gingivalis菌液混合,室温旋转,SEM观察P.gingivalis与A.viscosus间的共聚;将不同浓度的P.gingivalis和用放射性核素标记的A.viscosus混合,室温旋转1.5h,荧光闪烁记数法检测A.viscosus对S-HA的黏附量,以单菌种的A.viscosus作为对照,设定其黏附量为100%.采用SPSS10.07软件包对数据进行单因素方差分析,比较不同浓度P.gingivalis对A.viscosus黏附的影响.结果:1个A.viscosus的细胞表面可黏附多个P.gingivalis.P.gingivalis浓度较小时,A.viscosus对S-HA黏附量相对于对照组略增加;随P:gingivalis浓度增加,A.viscosus黏附量显著下降(P＜0.05).结论:A.viscosus和P.gingivalis可发生细菌之间的共集.这种共集可影响A.viscosus对S-HA的黏附.     

牙龈卟啉单胞菌上调钙结合蛋白1促进牙龈上皮细胞增殖

目的 探究钙结合蛋白1在牙龈卟啉单胞菌(P.gingivalis)影响牙龈上皮细胞增殖和凋亡中的作用.方法 P.gingivalis感染CA9-22细胞,在感染24 h后,采用实时荧光定量聚合酶链反应、免疫印迹法和免疫荧光法检测钙结合蛋白1(CALB1)的表达.通过RNA干扰法抑制CALB1表达,BrdU分析检测细胞增...     

牙龈卟啉单胞菌牙龈蛋白酶的研究进展

牙周炎是一种牙齿支持组织的慢性炎症性疾病,能引起结缔组织和牙槽骨的破坏而导致渐进性附着丧失,最终可能导致牙齿脱落.革兰氏阴性厌氧菌牙龈卟啉单胞菌是慢性牙周炎的重要致病菌,具有包括脂多糖、菌毛、血细胞凝集素和胞外蛋白酶在内的多种毒力因子,其中牙龈蛋白酶提供的蛋白水解活性占该生物体产生的一般蛋白水解活性的大部分(85％),...     

牙龈卟啉单胞菌研究进展

牙周炎是常见的口腔疾病之一,是中国成年人失牙的主要原因.牙龈卟啉单胞菌在引发牙周组织破坏过程中发挥着重要的作用,成为国内外学者研究的热点之一.本文就牙龈卟啉单胞菌与口腔疾病和其他全身性疾病的关系、牙龈卟啉单胞菌全基因组,牙龈卟啉单胞菌与牙龈上皮细胞的相互作用等研究作一综述,以拓宽牙龈卟啉单胞菌的研究思路,进血为牙周炎的...     

牙龈卟啉单胞菌与冠心病

牙周病是引起冠心病的危险因素之一,牙龈卟啉单胞菌是引起牙周病的主要致病菌,它可以侵入血管内膜导致血管壁增厚及释放内毒素,释放细胞因子促进血小板的聚集,血栓形成,从而导致心血管疾病的发生。     

牙龈卟啉单胞菌的分型及其致病作用

牙龈卟啉单胞菌被认为是牙周疾病最重要的致病菌之一，与多种牙周疾病特别是成年人牙周炎关系密切，本文对其生物学特性，血清分型，遗传分型的临床流行病学特点及其致病性等进行了综述。     

Interaction of Porphyromonas gingivalis with gingival epithelial cells maintained in culture.

Interactions between Porphyromonas gingivalis and gingival epithelial cells were investigated. Gingival epithelial cells were cultured from surgically removed gingival tissue. Electron microscopy demonstrated adherence of P. gingivalis to the cell membranes and microvilli followed by internalization of the bacteria into the epithelial cell cytoplasm. Saliva from healthy and periodontally diseased patients inhibited P. gingivalis association with the epithelial cells. Attachment to and penetration of gingival epithelial cells by P. gingivalis may be important virulence factors in periodontal disease. Salivary molecules may play a role in modulating these interactions.     

Adherence of Porphyromonas gingivalis to gingival epithelial cells: modulation of bacterial protein expression

The protein profiles of Porphyromonas gingivalis (ATCC 33277 and W83) bound to KB gingival epithelial cells were analyzed by SDS-PAGE and immunoblotting. We found that a 51-kDa component was formed in bacteria that adhered to the KB cells, whereas 26- to 29-kDa bands were less intensive, in contrast to the protein profile of free bacteria. P. gingivalis ATCC 33277 incubated with protease-treated KB cells retained the profile of free bacteria. These results demonstrate the specificity of bacterial recognition of eukaryotic membrane components.     

Adhesion and invasion to epithelial cells by fimA genotypes of Porphyromonas gingivalis

Adhesion to and invasion of epithelial cells by the periodontopathogen Porphyromonas gingivalis is promoted by the major fimbriae, encoded by fimA. The microorganism can be classified in six genotypes, based on fimA sequence, and genotype II strains are more prevalent than others in periodontitis patients. This study aimed to determine the adhesive and invasive abilities on KB cells of different fimA allelic variants of P. gingivalis isolates. Twenty-two isolates and six reference strains representing the six fimA genotypes and non-typeable strains were screened for their adhesion and invasion abilities on KB cells, using standard methods. All strains were able to adhere and, except for one, to invade KB cells. However, these properties were not homogeneous among strains belonging to the same genotype. There was no correlation between adhesion and invasion efficiencies. Isolate KdII 865 (fimA genotype II) was the most invasive and the second most adhesive strain, whereas reference strain ATCC 33277 (fimA I) showed a low adhesion ability but was highly invasive. These data indicated that fimA genotypes of P. gingivalis are not related to the adhesion and invasion abilities on KB cells, suggesting that the increased prevalence and proportion of certain genotypes may be attributed to other characteristics besides FimA variation.     

纤维蛋白原对牙龈卟啉单胞菌黏附口腔上皮细胞的影响

目的探讨血浆蛋白成分纤维蛋白原（Fg）在牙周病发病机制中的作用。方法体外培养口腔上皮细胞系KB细胞至单层融合，分别与不同浓度Fg溶液共同孵育，并加入以^3H-胸腺嘧啶核苷标记的牙龈卟啉单胞菌（Pg）行细菌感染攻击细胞实验。采用同位素闪烁光谱测定法检测黏附和内化于KB细胞的Pg数量。结果加入Fg的各实验组黏附和内化细菌量及细菌黏附和内化率均显著高于未加入Fg的对照组；不同Fg浓度的各组间黏附和内化细菌量及黏附和内化率差异亦有统计学意义，随着Fg浓度的升高，黏附和内化的细菌量显著增加。结论纤维蛋白原可促进Pg黏附于口腔上皮细胞，在牙周病的发生、发展中可能具有一定的病理学作用。     

牙龈卟啉单胞菌膜泡诱导牙龈上皮细胞炎性反应的体外研究

目的建立牙龈卟啉单胞菌膜泡诱导牙龈上皮细胞炎性反应的体外模型，探讨牙龈卟啉单胞菌在牙周炎中的致病作用。方法用酶联免疫吸附法检测牙龈卟啉单胞菌膜泡对牙龈上皮细胞前列腺素E2（prostaglandin E2，PGE2）分泌的影响，以实时反转录聚合酶链反应法检测牙龈卟啉单胞菌膜泡对牙龈上皮细胞环氧化物酶（cyclooxygenase，COX）-2和白细胞介素（interleukin，IL）-6、IL-8基因表达的作用。结果牙龈卟啉单胞菌膜泡浓度依赖性地促进了牙龈上皮细胞PGE2的分泌，并使COX-2、IL-6、IL-8的mRNA表达水平显著上调。结论牙龈卟啉单胞菌膜泡诱导牙龈上皮细胞发生的细胞炎性反应，可能是牙周炎发生、发展的重要因素。     

Effects of Porphyromonas gingivalis infection on human gingival epithelial barrier function in vitro

The gingival epithelium plays an important role in the protection of oral tissues from microbial challenge. Oral keratinocytes form various cellular contacts, including tight junctions, and thus are able to create an epithelial barrier. A measurable indicator of barrier function in vitro is the transepithelial electrical resistance (TER). Porphyromonas gingivalis is recognized as a major aetiologic agent of periodontal disease and exhibits a variety of virulence factors. The aim of the study was to investigate the effect, in vitro, of infection with P. gingivalis on gingival barriers composed of primary and immortalized human keratinocytes. Primary and immortalized human gingival keratinocytes were infected with different strains of P. gingivalis. The impact of the bacterial challenge on the barrier was analysed by measuring the TER. The destructive effects of gingipains were blocked by specific enzyme inhibitors. After an initial increase of about 20-30% in infected wells, the TER decreased to zero. Gingipain inhibitors delayed the destruction of the barrier by 12 ± 4 h. In all cases, the loss of TER was accelerated if the system was infected from the basolateral side. A distinct effect of P. gingivalis on the epithelial barrier function of three-dimensional cultured epithelial cell models was demonstrated, which can partly be attributed to the activity of gingipains.     

Binding of the periodontitis associated bacterium Porphyromonas gingivalis to glycoproteins from human epithelial cells

Introduction:  In the present study we examined the ability of the periodontal pathogen Porphyromonas gingivalis to adhere to glycoconjugates on intact cells and to protein preparations of epithelial cells (KB cells).
Methods:  The KB cell protein preparation was separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and transferred to nitrocellulose membranes by Western blotting. The membranes were used in overlay assays with labeled P. gingivalis . Flow cytometry was used to analyze attachment of bacteria to intact KB cells.
Results:  Glycoconjugate expression on the KB cells and in the protein preparation was confirmed. Binding was detected to several bands on the Western blots. Flow cytometry showed a distinct increase in fluorescence for strain FDC 381. Preincubation of the bacteria with mannose, fucose, N -acetylglucosamine and N -acetylgalactosamine inhibited the binding to KB cells by approximately 30% whereas preincubation with N -acetylneuraminic acid reduced the binding by 60%.
Conclusion:  These results indicate that carbohydrate structures are involved in the binding process of P. gingivalis to oral epithelial cells and that neuraminic acid plays a significant role in the adhesion process.