IMMUNODOMINANT STRESS PROTEINS OF P. GINGIVALIS

牙龈卟啉单胞菌的免疫显性应激蛋白

• 批准号: 6634634
• 负责人: DENNIS E LOPATIN
• 金额: $ 31.74万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-04-01 至 2006-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6634634
• 关键词: Bacteroides gingivalis; bacterial antigens; bacterial genetics; bacterial proteins; bactericidal immunity; disease /disorder model; gel electrophoresis; gene expression; genetic strain; immune tolerance /unresponsiveness; immunoelectron microscopy; immunologic assay /test; immunoprecipitation; laboratory mouse; laboratory rabbit; monoclonal antibody; mutant; nucleic acid sequence; periodontium disorder; polymerase chain reaction; protease inhibitor; protein sequence; protein structure function; stress proteins; virulence

Studies performed in our laboratory implicate the Porphyromonas gingivalis HtpG stress protein, the prokaryotic homologue of Hsp90, in the etiology of periodontal disease. We have reported that elevated levels of anti-Hsp90 antibodies, concomitant with P. gingivalis colonization, are associated with periodontal health. Transcription of HtpG message was also found to be upregulated 7-10-fold in P. gingivalis obtained from diseased subgingival plaque. There is a precedence for Hsp90 homologues contributing to pathogenicity of other microorganisms. Immunity to a single Hsp90 epitope of Candida albicans has been demonstrated to confer protection against systemic candidiasis. Studies performed by our laboratory have revealed that P. gingivalis HtpG has a significant degree of homology with human Hsp90, but remains clearly distinct from other HtpG proteins due to its unique C-terminal region. We have found that HtpG is localized to P. gingivalis membranes and extracellular vesicles, and that it cross-reacts with other prokaryotic and eukaryotic Hsp90 homologues. Our findings suggest that HtpG is readily accessible to participate in host cellular invasion processes, as well as to interfere with normal host cell functions one P. gingivalis enters the host cytoplasmic compartment. Transfection of KB cells with the P. gingivalis htpG gene stimulates IL-8 production by these cells. This application proposes to extend our investigations into the role that molecular mimicry by HtpG plays in the pathogenicity of P. gingivalis. Previous studies of other pathogenic microorganisms which appear to use the Hsp90 homologue as a virulence factor have been purely descriptive. Our application is unique in that while will propose to evaluate the role of HtpG in adherence and invasion mechanisms, we also propose to elucidate novel pathogenic mechanism(s) by which microorganisms such as P. gingivalis utilize molecular mimicry to disrupt normal eukaryotic cell function(s). Since the most clearly defined eukaryotic Hsp90-mediated mechanisms involved signal transduction pathways, these will be the primary foci of our investigations. The hypothesis to be tested in this study is: 1) HtpG plays a role in adherence and invasion of host cells; and 2) once internalized, signal transduction mechanisms mediated by Hsp90/TRAP1 within eukaryotic cells are disrupted by the HtpG of P. gingivalis through molecular mimicry. This leads to disruption of normal inflammatory cytokine responses to microbial invasion by P. gingivalis and other oral microorganisms.

我们实验室的研究表明牙龈卟啉单胞菌HtpG应激蛋白（Hsp 90的原核同源物）与牙周病的病因有关。 我们已经报道了抗Hsp 90抗体水平的升高，伴随着牙龈卟啉单胞菌的定植，与牙周健康有关。 还发现在从患病龈下菌斑获得的牙龈卟啉单胞菌中，HtpG信息的转录上调7-10倍。 Hsp 90同源物对其他微生物的致病性有贡献。对白色念珠菌的单一Hsp 90表位的免疫已被证明赋予针对系统性念珠菌病的保护。我们实验室进行的研究表明，牙龈卟啉单胞菌HtpG与人Hsp 90具有显著程度的同源性，但由于其独特的C-末端区域，与其他HtpG蛋白仍有明显区别。 我们已经发现，HtpG定位于牙龈卟啉单胞菌膜和细胞外囊泡，并且它与其他原核和真核Hsp 90同源物交叉反应。 我们的研究结果表明，HtpG是容易参与宿主细胞的入侵过程，以及干扰正常的宿主细胞功能的牙龈卟啉单胞菌进入宿主细胞质区室。 用牙龈卟啉单胞菌htpG基因转染KB细胞刺激这些细胞产生IL-8。本申请旨在将我们的研究扩展到HtpG分子模拟在牙龈卟啉单胞菌致病性中的作用。 以前的研究其他病原微生物似乎使用Hsp 90同源物作为毒力因子已经纯粹是描述。 我们的申请是独特的，因为我们将提出评估HtpG在粘附和侵袭机制中的作用，我们还提出阐明微生物如牙龈卟啉单胞菌利用分子模拟破坏正常真核细胞功能的新致病机制。 由于最明确的真核Hsp 90介导的机制涉及信号转导途径，这些将是我们的调查的主要焦点。在本研究中要检验的假设是：1）HtpG在宿主细胞的粘附和侵袭中起作用;和2）一旦内化，真核细胞内由Hsp 90/TRAP 1介导的信号转导机制被牙龈卟啉单胞菌的HtpG通过分子模拟破坏。 这导致对牙龈卟啉单胞菌和其他口腔微生物的微生物入侵的正常炎性细胞因子应答的破坏。