Porphyromonas gingivalis gingipains mediate the shedding of syndecan-1 from the surface of gingival epithelial cells

Porphyromonas gingivalis gingipains are thought to be critical virulence factors in periodontitis. Increased serum levels of the soluble ectodomains of surface effectors have been reported to occur during bacterial infections. In the present study, we show that the cell surface proteoglycan syndecan-1 was highly expressed on human gingival epithelial cells. Treatments with P. gingivalis culture supernatants consistently mediated the shedding of syndecan-1 from the surface of epithelial cells. Concomitantly, the amount of soluble syndecan-1 detected in the culture medium increased significantly in a time-dependent manner. However, neither a heat-inactivated supernatant nor a supernatant from a gingipain-deficient mutant had a significant effect on syndecan-1 shedding. Such a shedding process may play an important role in the bacterial invasion of periodontal tissue and the modulation of host defences.     

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.     

Porphyromonas gingivalis gingipains mediate the shedding of syndecan‐1 from the surface of gingival epithelial cells

Porphyromonas gingivalis gingipains are thought to be critical virulence factors in periodontitis. Increased serum levels of the soluble ectodomains of surface effectors have been reported to occur during bacterial infections. In the present study, we show that the cell surface proteoglycan syndecan‐1 was highly expressed on human gingival epithelial cells. Treatments with P. gingivalis culture supernatants consistently mediated the shedding of syndecan‐1 from the surface of epithelial cells. Concomitantly, the amount of soluble syndecan‐1 detected in the culture medium increased significantly in a time‐dependent manner. However, neither a heat‐inactivated supernatant nor a supernatant from a gingipain‐deficient mutant had a significant effect on syndecan‐1 shedding. Such a shedding process may play an important role in the bacterial invasion of periodontal tissue and the modulation of host defences.     

Porphyromonas gingivalis stimulates TACE production by T cells

Introduction: Tumour necrosis factor‐α converting enzyme (TACE), also known as ADAM17, is a membrane‐bound metalloprotease and disintegrin. It is produced by a number of host cells and is known to shed and release cell‐bound cytokines, particularly members of the tumour necrosis factor family. The aim of this study was to investigate the effect of Porphyromonas gingivalis on TACE production by a human T‐cell line, to identify putative virulence factors involved in this process, and to investigate the effect of doxycycline. Methods: P. gingivalis 6‐day culture supernatants were used to challenge Jurkat T cells for 6 h. Secreted and cell‐associated TACE levels were measured by enzyme‐linked immunosorbent assay, whereas messenger RNA expression was investigated by quantitative real‐time polymerase chain reaction. To investigate the involvement of cysteine proteases or proteinaceous components in general, P. gingivalis culture supernatants were treated with the specific chemical inhibitor TLCK or heat‐inactivated, respectively. The effect of doxycycline on the regulation of TACE secretion by P. gingivalis was also investigated. Results: P. gingivalis challenge resulted in a concentration‐dependent enhancement of TACE messenger RNA expression and protein release by Jurkat cells. TLCK treatment or heat treatment of P. gingivalis culture supernatants decreased TACE release to control levels. Doxycycline inhibited TACE secretion dose dependently. Conclusion: The induction of TACE by T cells in response to P. gingivalis may in turn favour the shedding of host cell‐bound cytokines into the local microenvironment, potentially amplifying the inflammatory response. In the present experimental system, P. gingivalis cysteine proteases are involved in TACE release by T cells.     

Activation of serum complement by polysaccharide-containing antigens of Porphyromonas gingivalis

We previosly reported that hot aqueous phenol extraction of Porphyromonas gingivalis yields a preparation containing both lipopolysaccharide (LPS) and an antigenically distinct capsular polysaccharide (PS). In the present study, we examined the capacity of phenol-water extracts from a number of strains of P. gingivalis to activate human serum complement. Anticomplementary activity of extracts from two invasive and two noninvasive strains of P. gingivalis was assessed in a sheep erythrocyte hemolytic assay and in an alternative pathway-selective rabbit erythrocyte hemolytic assay. In the sheep erythrocyte assay, extracts from noninvasive strains were found to exhibit greater anticomplementary activity than extracts derived from invasive strains. A phenol-water extract from invasive strain ATCC 53977 was further resolved into its LPS and PS fractions. Whereas isolated LPS from this strain exhibited strong anticomplementary activity, the PS fraction was only weakly active. Phenol-water extracts from three of four strains were found to be potent activators of the alternative pathway, with extracts from the two noninvasive strains being most active. The extract from the remaining strain (ATCC 53977) was a poor activator of the alternative pathway. Further analysis of this extract revealed, however, that the LPS fraction was a potent activator of the alternative pathway, although the PS fraction exhibited negligible activity. The results of this study indicate that phenol-water extracts of invasive and noninvasive strains of P. gingivalis differ in their respective anticomplementary activities, with invasive strains being less active. Although extracts from both invasive and noninvasive strains activated the alternative pathway, this activity appears to be attributable to the LPS, rather than the PS, component.     

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。     

不同fimA基因型牙龈卟啉单胞菌刺激口腔上皮细胞白细胞介素-8的表达

目的比较不同fimA基因型牙龈卟啉单胞菌（P.gingivalis）刺激下口腔上皮细胞白细胞介素-8（IL-8）的表达水平,初步探讨P.gingivalis致病性与其fimA基因型的关系。方法P.gingivalis ATCC 33277（Ⅰ型fimA）、W83、47A-1（Ⅳ型fimA）和KB细胞ATCC CCL-17共同孵育24 h,以未受刺激的KB细胞作为对照组,分别在1、3、6、24 h收集细胞和培养上清液。RT-PCR检测KB细胞IL-8 mRNA的动态表达,酶联免疫反应检测培养上清液中IL-8的动态变化。结果2种fimA基因型菌株刺激1 h,KB细胞IL-8 mRNA的表达上调至峰值,高于对照组,3~24 h IL-8 mRNA的表达水平接近对照组;P.gingivalis感染细胞后3~24 h,上清液中的IL-8水平低于对照组,Ⅳ型菌株低于Ⅰ型菌株;IL-8 mRNA及其蛋白表达不完全一致,提示IL-8的表达存在转录后水平的调节。结论fimA基因型与口腔上皮细胞IL-8的表达水平相关,提示P.gingivalis致病性与其fimA基因型相关。     

牙龈卟啉单胞菌基因真核表达载体构建及其在哺乳动物细胞中的表达

目的　构建分泌型牙龈卟啉单胞菌牙龈蛋白酶K基因的真核表达载体VR1020/KGPcd,并检测其在哺乳动物细胞中的表达及分泌情况。方法　应用基因重组方法,构建真核表达载体VR1020/KGPcd。然后用Lipofectamine 2000介导瞬时转染COS7细胞,以反转录聚合酶链反应(RT-PCR)和间接免疫荧光检测重组质粒的基因转录和蛋白表达,酶联免疫吸附实验(ELISA)检测培养上清中蛋白分泌情况。结果　转染的COS7细胞中可检测到目的基因的转录和表达,并且在培养的上清中检测到其表达的蛋白质。结论　成功构建了可分泌表达的真核表达载体 VR1020/KGPcd,并在哺乳动物细胞中能够正确转录和翻译,培养上清中可检测到正确表达的目的蛋白,这为其作为基因疫苗免疫动物奠定了基础。     

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.     

两种基因型牙龈卟啉单胞菌对上皮细胞的影响

目的 比较2种fimA基因型牙龈卟啉单胞菌(Porphyromonas gingivalis,P.g)刺激下口腔上皮细胞白介素-6( Interlukin-6,IL-6)的表达.方法 以未受P.g刺激的上皮细胞作为对照组,实验组用P.g ATCC 33277(I型菌毛组)和W83、47A-1(Ⅳ型菌毛组)分别与口腔上...     

Porphyromonas gingivalis survives within KB cells and modulates inflammatory response

BACKGROUND/AIMS: The purpose of the study was to investigate the intracellular survival of Porphyromonas gingivalis as a possible mechanism for maintaining periodontitis. METHODS: P. gingivalis strains, the strain ATCC 33277 and seven clinical isolates, were co-cultured with KB cells. The number of intracellular bacteria was determined up to 3 days after infection. In addition, the numbers of KB cells per well, the concentrations of the cytokines interleukin-1beta (IL-1beta), IL-6, IL-8 and tumour necrosis factor-alpha (TNF-alpha) and the arginine-specific amidolytic activity were measured. The 16S rRNA of P. gingivalis and the mRNA expression of IL-1beta, IL-6, IL-8, TNF-alpha and rgpA were also determined. RESULTS: All the P. gingivalis strains studied were able to survive within KB cells. In contrast to the reduced values of colony-forming units at day 3, equal and higher levels of 16S rRNA were seen in comparison to day 0. Arginine-specific amidolytic activity declined in all samples during infection. Expression of mRNA for rgpA was not found after infection of KB cells by P. gingivalis strains. IL-8 was detectable in all samples 2 days after infection with P. gingivalis strains. Principal components analysis underlined a correlation between the arginine-specific amidolytic activity 1 h after infection and both the released IL-8 and the mRNA expression of IL-8. Associations were found between the cultivable numbers of intracellular P. gingivalis and the mRNAs of IL-1, IL-6 and TNF-alpha at the day of infection. CONCLUSION: The results indicate survival of P. gingivalis within epithelial cells, possibly in a non-cultivable stage. Invasion into cells modulates the virulence properties of P. gingivalis as well as the inflammatory response of the cells.     

Predominant immunoreactivity of Porphyromonas gingivalis heat shock protein in autoimmune diseases

Jeong E, Lee J‐Y, Kim S‐J, Choi J. Predominant immunoreactivity of Porphyromonas gingivalis heat shock protein in autoimmune diseases. J Periodont Res 2012; 47: 811–816. © 2012 John Wiley & Sons A/S Background and Objective: Autoimmune diseases, including atherosclerosis, diabetes mellitus and rheumatoid arthritis, can be triggered and aggravated by the pathogen‐driven antigenic peptide from Porphyromonas gingivalis HSP60. P. gingivalis is the major pathogen of chronic periodontitis, which is a global epidemic prevalent in two‐thirds of the adult population. The monoclonal antibody raised against peptide 19 (Pep19: TLVVNRLRGSLKICAVKAPG) from P. gingivalis HSP60 was polyreactive to the human homolog. The aim of this study was to determine if Pep19 from P. gingivalis HSP60 manifests itself as a predominant antigen in infection‐triggered autoimmune diseases. Material and Methods: Pep19 from P. gingivalis HSP60, Mycobacterium tuberculosis HSP60 and Chlamydia pneumoniae HSP60 was synthesized for comparative recognition by the sera from patients with atherosclerosis, type 2 diabetes and rheumatoid arthritis, all with ongoing periodontal disease, and by the sera of a control group of patients with periodontal disease but with no history of atherosclerosis, type 2 diabetes or rheumatoid arthritis. Results: Of the Pep19 peptides from P. gingivalis HSP60, M. tuberculosis HSP60 and C. pneumoniae HSP60, Pep19 from P. gingivalis HSP60 was the peptide epitope predominantly and most consistently recognized by the serum samples of the four disease groups (chronic periodontitis, atherosclerosis, type 2 diabetes mellitus and rheumatoid arthritis). Conclusion: Seroreactivity to Pep19 of P. gingivalis HSP60, an oral pathogen, was predominant in patients with autoimmune disease with ongoing periodontal disease.     

牙龈卟啉单胞菌精氨酸牙龈素催化结构域基因的克隆及其在大肠杆菌中的表达

目的 克隆牙龈卟啉单胞菌精氨酸牙龈素催化结构域（RgpAcd）基因,并将其置于大肠杆菌中作融合表
达。方法 利用PCR技术和基因重组技术,克隆牙龈卟啉单胞菌RgpAcd,然后插入中介载体pMD18-T中并测序鉴定。将目的基因片段插入原核表达载体pET-15b来构建表达质粒pET-15b/RgpAcd。重组原核表达质粒经酶切鉴定后转化大肠杆菌BL21感受态细胞,以异丙基硫代-β-D-半乳糖苷（IPTG）诱导表达融合蛋白。结果 核酸序列测定与分析的结果表明,克隆的1 476 bp基因序列与GenBank数据库中的序列呈现100%同源性;IPTG诱导后的菌体经SDS-聚丙烯酰胺凝胶电泳后有一个相对分子质量为5×104的融合表达蛋白产生。结论 本实验成功克隆了牙龈卟啉单胞菌RgpAcd基因,并在大肠杆菌中表达了RgpAcd蛋白,为进一步研制重组活载体疫苗奠定了基础。     

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...     

两种fimA基因型牙龈卟啉单胞菌刺激下口腔上皮细胞ICAM-1的表达

目的比较2种fimA基因型牙龈卟啉单胞菌（Porphyromonas gingivalis,P．gingivalis）刺激下口腔上皮细胞ICAM-1的表达水平。方法实验组用P．gingivalis ATCC 33277（Ⅰ型菌毛组）,W83（Ⅳ型菌毛组）,47A-1（Ⅳ型菌毛组）分别与KB细胞（ATCC CCL17）共同孵育24h;对照组为未受P.gingivalis刺激的KB细胞。分别在1h、3h、6h和24h收集细胞,运用流式细胞仪检测KB细胞膜上ICAM-1的动态表达。结果P．gingivalis刺激细胞后3h、6h和24h,实验组ICAM-1的表达水平均高于对照组;2种fimA基因型P．gingivalis调节KB细胞表达ICAM-1的方式相似,Ⅳ型菌毛组的调节作用强于Ⅰ型菌毛组。结论P.gingivalis上调口腔上皮细胞表达ICAM-1的水平与其fimA基因型相关,提示P.gingivalis致病性与其fimA基因型相关。     

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。     

Interleukin‐1 receptor‐associated kinase‐M in gingival epithelial cells attenuates the inflammatory response elicited by Porphyromonas gingivalis

Takahashi N, Honda T, Domon H, Nakajima T, Tabeta K, Yamazaki K. Interleukin‐1 receptor‐associated kinase‐M in gingival epithelial cells attenuates the inflammatory response elicited by Porphyromonas gingivalis. J Periodont Res 2010; 45: 512–519. © 2010 John Wiley & Sons A/S Background and Objective: Recent studies have revealed that negative regulatory molecules, including interleukin‐1 receptor‐associated kinase‐M (IRAK‐M), control the overactivation of Toll‐like receptor (TLR) signaling. The role of IRAK‐M in human gingival epithelial cells (HGECs), which express TLRs, remains unclear. The present study examined the role of IRAK‐M on interleukin‐8 and macrophage chemoattractant protein‐1 (MCP‐1) expression in HGECs stimulated with Porphyromonas gingivalis and TLR ligands. Material and Methods: Primary HGECs and an SV40 T‐antigen‐immortalized HGEC line (epi 4) were stimulated with live or heat‐killed P. gingivalis, P. gingivalis lipopolysaccharide or the synthetic lipopeptide PAM₃CSK₄, and subsequent expression of IRAK‐M, interleukin‐8 and MCP‐1 was evaluated at the mRNA and protein levels. The effects of IRAK‐M on interleukin‐8 and MCP‐1 expressions were evaluated by IRAK‐M‐specific RNA interference (RNAi)‐based loss‐of‐function assay. Results: All tested stimulants up‐regulated the expression of IRAK‐M in HGECs. The P. gingivalis lipopolysaccharide or PAM₃CSK₄ increased MCP‐1 expression, whereas live P. gingivalis down‐regulated the MCP‐1 expression in HGECs. However, IRAK‐M RNAi increased the expression of MCP‐1 irrespective of up‐ or down‐regulation mediated by the respective stimulants. Interleukin‐8 gene expression, up‐regulated by all tested stimulants, was further enhanced by IRAK‐M RNAi. In contrast, IRAK‐M RNAi had no effect on the interleukin‐8 protein levels, irrespective of the stimulant, indicating that post‐translational modification, not IRAK‐M, controls interleukin‐8 protein expression. Conclusion: Interleukin‐1 receptor‐associated kinase‐M appeared to have distinct regulatory roles on the interleukin‐8 and MCP‐1 produced by HGECs, further suggesting an important role for interleukin‐8 in the immune reponse to periodontopathic bacteria.     

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.