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: 8753275
• 负责人: KEITH Peter MINTZ
• 金额: $ 73.62万
• 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/8753275
• 关键词: Actinobacillus actinomycetemcomitans; Adhesions; Adhesives; Amino Acids; Anabolism; Bacteria; Bacterial Adhesins; Bacterial Adhesion; Bacterial Proteins; Binding; Biochemical; Cardiovascular Diseases; Cell surface; Chemosensitization; Chimeric Proteins; Chronic; Clinical; Collagen; Complex; Comprehension; Development; Disease; Disease Attributes; Disease Progression; Dissection; Distal; Distant; Enzymes; Event; Evolution; Extracellular Matrix; Extracellular Matrix Proteins; Future; Genes; Genetic Techniques; Genotype; Gingiva; Goals; Gram-Negative Bacteria; 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; Protein Binding; 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; public health relevance; 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）：牙周病代表一组炎症性疾病，其导致牙龈和牙齿支撑结构的破坏。组织损失是由于特定龈下细菌定植引起的宿主免疫反应失衡所致。这种微生物群也被认为是口腔外疾病的根源。放线菌聚集菌是一种革兰氏阴性牙周病原体，与该疾病的慢性和局部侵袭性形式相关。多种播散性口腔外疾病都是由这种病原体引起的，包括感染性心内膜炎和心血管疾病的加重。然而，A. actinomycetemcomitans 用于在口腔定殖或渗透并传播到远处组织的趋向性仍然难以捉摸。这些组织具有共同的细胞外基质 (ECM) 蛋白，包括胶原蛋白。我们的小组发现了一种新的蛋白质，细胞外基质蛋白粘附素 A (EmaA)，它对于细菌与胶原蛋白的相互作用至关重要，并且是感染性心内膜炎引发的毒力决定因素。总之，A. actinomycetemcomitans 表达细胞表面粘附素，该粘附素与胶原蛋白（最丰富的 ECM 蛋白）结合，用于建立感染灶。因此，我们假设 ECM 定植充当龈沟再次感染和传播到外部的储存库。 口腔部位。 EmaA 粘附素由 A. actinomycetemcomitans 特有的三个相同单体组成，这些单体插入外膜中，组装出胶原蛋白结合所必需的独特天线状表面附属物。然而，单体的蛋白质大小和序列是血清型特异性的。此外，EmaA 还经过 O-多糖 (O-PS) 糖的翻译后修饰，这对于与胶原蛋白的结合至关重要。有趣的是，这种 EmaA 修饰与 O-PS 生物合成所需的酶相同。聚糖部分在与胶原蛋白相互作用中的具体作用仍不清楚。该应用程序的目标是 阐明该病原体在口腔定植并传播到其他组织的机制。为了实现这一目标，我们提出以下具体目标：1）确定 b 血清型细菌中 EmaA 聚糖部分的定位和组成； 2)确定EmaA基因型和细菌血清型在胶原结合中的作用； 3) EmaA/胶原蛋白相互作用的生化和生物物理测定。定义 EmaA 活性结合部分的性质将有助于理解该蛋白在 A. actinomycetemcomitans 发病机制中的作用。从这项研究中获得的关于这种粘附素分子机制的新见解将导致开发出破坏和/或减少这种病原体组织定植的分子。