Dissecting the role of sialic acid and sialidase in the pathophysiology of Porphyromonas gingivalis

剖析唾液酸和唾液酸酶在牙龈卟啉单胞菌病理生理学中的作用

• 批准号: 10350709
• 负责人: Chunhao Chris Li
• 金额: $ 48.43万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-15 至 2026-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10350709
• 关键词: 3-Dimensional; Address; Adherence; Alveolar Bone Loss; Alzheimer' s Disease; Anabolism; Arthritis; Bacteria; Binding Sites; Biochemical; Biochemistry; Biological; Biological Assay; Biological Markers; Biological Process; Biophysics; Carbon; Cardiovascular Diseases; Cell Communication; Cell Surface Receptors; Cell surface; Cells; Charge; Clinical Research; Complement; Crystallography; Data; Development; Diabetes Mellitus; Diagnosis; Dose; Embryonic Development; Enzymes; Excision; Forsythia; Functional disorder; Future; Genes; Genetic; Genome; Gingival Crevicular Fluid; Glycobiology; Glycoconjugates; Goals; Growth; Human; Immune; Immune Evasion; Immune system; Immunoglobulins; Immunology; Impairment; In Vitro; Inflammation; Innate Immune Response; Intercept; Kinetics; Lead; Ligands; Lipopolysaccharides; Measures; Mediating; Membrane Proteins; Microbial Biofilms; Modality; Molecular; Mucins; Mucous Membrane; Neuraminic Acids; Neuraminidase; Neurologic; Nutrient; Oral cavity; Pathogenesis; Pathogenicity; Pathway interactions; Periodontal Diseases; Periodontitis; Phagocytosis; Phenotype; Play; Polysaccharides; Porphyromonas gingivalis; Positioning Attribute; Proteins; Reporting; Resistance; Role; Salivary; Series; Severities; Sialic Acids; Side; Structure; Substrate Specificity; Sugar Acids; Surface; Testing; Toll-like receptors; Vagina; Virulence; Virulence Factors; antimicrobial; biological adaptation to stress; capsule; cell growth; chemokine; complement system; design; dietary; experimental study; fitness; genetic approach; gut bacteria; gut microbiome; immune function; immunoregulation; in vivo; inhibitor; insight; interdisciplinary approach; macrophage; mouse model; nano; neutrophil; novel; oral bacteria; oral pathogen; pathogen; pathogenic bacteria; patient response; polymicrobial biofilm; prevent; response; sialic acid permease; structural biology; treatment response; uptake

The overarching goal of this application is to investigate the role of sialidase and sialic acid in the keystone pathogen Porphyromonas gingivalis (Pg) and their contributions to the pathogenesis of periodontitis. Sialic acid (SA), a group of structurally related nine-carbon sugar acids, plays critical roles in host-pathogen interactions. On the host side, mammalian mucosal surfaces and secretions of the mouth, airway, gut, and vagina are especially sialoglycan-rich, which have a variety of biological, biophysical, antimicrobial, and immunological functions. In addition, a number of cell surface receptors (e.g., chemokine-, immunoglobulin-, and toll-like- receptors) are either sialylated or recognize sialylated ligands, which play critical roles in immune recognition and activation. On the pathogen side, many bacterial pathogens have evolved different mechanisms to target host SA for adherence, invasion, immune modulation and nutrient acquisition, thereby promoting their fitness and pathogenesis. Specifically, bacterial pathogens often use sialidases to hydrolyze host sialoglycans, compromise host immune defenses, and promote their survival in the mucosal niche. Salivary and gingival crevicular fluids contain a high concentration of SA bound to sialoglycans in various proteins such as mucins. Clinical studies indicate that sialidase activity in the oral cavity is positively associated with the severity of periodontitis; thus, it is recommended as a biomarker for periodontitis diagnosis. Accordingly, sialidases have been found in numerous oral bacteria including the keystone pathogen Porphyromonas gingivalis (Pg). Pg lacks genes to synthesize SA. Instead, it encodes a sialidase (PG0352), which is highly conserved among all genome sequenced Pg isolates. Previous studies from our group and others have shown that PG0352 plays a crucial role in Pg capsule synthesis, biofilms, stress response, innate immune responses, and virulence. However, the molecular mechanism underlying these phenotypes remains elusive. In this application, we hypothesize that Pg employs a sialidase and a SA specific transporter to scavenge host SA, which is in turn used to modify Pg cell surface molecules such as capsule and lipopolysaccharide (LPS), thereby intercepting host innate immune defenses, such as complement killing and phagocytosis of neutrophils and macrophage. To test this hypothesis, the following studies are specifically designed and will be implemented: Aim 1: To delineate the biochemical and structural features of PG0352 by using an approach of genetics, biochemistry, and crystallography; Aim 2: To investigate how Pg imports and utilizes SA by using a multidisciplinary approach of genetics, biochemistry, glycobiology, immunology, and biofilm assays; and Aim 3: To elucidate the role of PG0352 in the pathogenicity of Pg by using various in vitro and in vivo approaches. Completion of this project will not only provide mechanistic insights into understanding the role of SA and sialidase in the pathophysiology of Pg and perhaps other oral pathogens as well, but also will pave a way for future development of specific sialidase inhibitors against oral pathogens, which can provide alternatives to mitigate periodontal diseases.

这个应用的首要目标是研究唾液酸酶和唾液酸在keystone中的作用