Interactions of the oral pathogen, A. actinomycetemcomitans, with collagen

口腔病原体 A. actinomycetemcomitans 与胶原蛋白的相互作用

• 批准号: 9110715
• 负责人: KEITH Peter MINTZ
• 金额: $ 70.79万
• 依托单位: UNIVERSITY OF VERMONT & ST AGRIC COLLEGE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9110715
• 关键词: Actinobacillus actinomycetemcomitans; Adhesions; Adhesives; Amino Acids; Anabolism; Bacteria; Bacterial Adhesins; Bacterial Adhesion; Bacterial Proteins; Binding; Binding Proteins; Biochemical; Cardiovascular Diseases; Cell surface; Chemosensitization; Chimeric Proteins; Chronic; Clinical; Collagen; Complex; Comprehension; Development; Disease; Disease Progression; Dissection; Distal; Distant; Enzymes; Event; Evolution; Extracellular Matrix; Extracellular Matrix Proteins; Future; Genes; Genetic Techniques; Genotype; Gingiva; Goals; Gram-Negative Bacteria; Health; Heart Valves; Heterogeneity; Human; Immune response; Infection; Infective endocarditis; Inflammatory; Investigation; Kinetics; Knowledge; Laboratories; Lead; Light; Lipopolysaccharides; Location; Membrane; Modeling; Modification; Molecular; Mouth Diseases; N-terminal; Nature; Oral; Oral cavity; Pathogenesis; Periodontal Diseases; Periodontal Pocket; Periodontium; Phase; Play; Polysaccharides; Population; Post-Translational Protein Processing; Process; Proteins; Public Health; Reagent; Resolution; Role; Sequence Deletion; Serotyping; Site; Source; Structure of gingival sulcus; Surface; Systemic disease; Systemic infection; Testing; Tissues; Tropism; Virulence; antimicrobial; antimicrobial drug; appendage; base; biophysical techniques; combat; electron tomography; glycosylation; improved; insight; monomer; mutant; novel; novel therapeutics; oral pathogen; oral tissue; pathogen; polypeptide; prevent; resistant strain; single molecule; sugar; three dimensional structure

DESCRIPTION (provided by applicant): Periodontal disease represents a group of inflammatory diseases, which lead to the destruction of the gingiva and the supporting structures of the teeth. The loss of tissue results from an imbalance of the host immune response induced by the colonization of specific sub-gingival bacteria. This microflora is also considered the source for extra-oral diseases. Aggregatibacter actinomycetemcomitans is a Gram-negative periodontal pathogen associated with both the chronic and localized aggressive forms of the disease. Multiple disseminated extra-oral diseases are attributed to this pathogen including infective endocarditis and the potentiation of cardiovascular disease. However, the tropism used by A. actinomycetemcomitans to colonize the oral cavity or infiltrate and disseminate to distant tissues has remained elusive. These tissues share common extracellular matrix (ECM) proteins including collagen. Our group has identified a novel protein, extracellular matrix protein adhesin A (EmaA), which is critical for the interaction of the bacterium with collagens and is a proven virulence determinant for the initiation of infective endocarditis. In summary, A. actinomycetemcomitans expresses a cell surface adhesin that binds collagen, the most abundant ECM protein, for establishing infectious foci. Therefore, we posit that ECM colonization acts as a reservoir for re-infection of the gingival sulcus and dissemination to extra oral sites. The EmaA adhesin is composed of three identical monomers unique to A. actinomycetemcomitans that intercalate in the outer membrane to assemble unique antenna-like surface appendages essential for collagen binding. However, the protein size and sequence of the monomers is serotype specific. Furthermore, EmaA is posttranslationally modified with O-polysaccharide (O-PS) sugars that are crucial for binding to collagen. Interestingly, this EmaA modification shares the same enzymes required for O-PS biosynthesis. The specific role of the glycan moieties in the interaction with collagen remains undefined. The goal of this application is to elucidate the mechanism(s) utilized by this pathogen for colonizing the oral cavity and disseminating to other tissues. To achieve this goal we propose the following specific aims: 1) determine the localization and composition of the glycan moiety of EmaA from serotype b bacteria; 2) determine the role of EmaA genotype and bacterial serotype in collagen binding; and 3) biochemical and biophysical determination of the EmaA/collagen interaction. Defining the nature of the active binding moiety of EmaA will aid in understanding the role of this protein in the pathogenesis of A. actinomycetemcomitans. The new insights gained from this study into the molecular mechanism of this adhesin will lead to the development of molecules to disrupt and/or diminish tissue colonization by this pathogen.

描述（由申请人提供）：牙周病是一组炎症性疾病，导致牙龈和牙齿支撑结构的破坏。组织的损失是由特定牙龈下细菌定植引起的宿主免疫反应的不平衡造成的。这种微生物群也被认为是口腔外疾病的来源。放线菌聚集菌是一种革兰氏阴性牙周病原体，与慢性和局部侵袭性牙周疾病有关。多种弥散性口腔外疾病可归因于该病原体，包括感染性心内膜炎和心血管疾病的加剧。然而，放线菌属细菌在口腔定植或向远处组织浸润和传播的趋向性仍然是难以捉摸的。这些组织共享细胞外基质（ECM）蛋白，包括胶原蛋白。我们的研究小组已经发现了一种新的蛋白，细胞外基质蛋白粘附素a (EmaA)，它对细菌与胶原蛋白的相互作用至关重要，并且被证明是感染性心内膜炎开始的毒力决定因素。总之，a .放线菌comitans表达一种结合胶原蛋白的细胞表面粘附素，胶原蛋白是最丰富的ECM蛋白，用于建立感染灶。因此，我们假设ECM定植作为一个水库的再次感染牙龈沟和传播到额外的