Listeriosis Pathogenesis: Effect of Serogroup-specific Wall Teichoic Acid Changes

李斯特菌病发病机制：血清群特异性壁磷壁酸变化的影响

• 批准号: 8660618
• 负责人: PAUL Edwin ORNDORFF
• 金额: $ 22.73万
• 依托单位: NORTH CAROLINA STATE UNIVERSITY RALEIGH
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-05-15 至 2016-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8660618
• 关键词: Anabolism; Animals; Area; Attenuated; Biochemical; Biological; Biological Assay; Cells; Deletion Mutation; Development; Diagnosis; Diagnostic; Diagnostic Specificity; Disease; Disease Outbreaks; Enterocytes; Epidemiologic Studies; Generations; Genes; Growth; Health; Human; Immune; Immunocompromised Host; In Vitro; Individual; Infection; Inflammatory; Intestines; Knowledge; Laboratories; Lectin; Listeria monocytogenes; Listeriosis; Modality; Modeling; Mononuclear; Mus; National Health Policy; Oral; Pathogenesis; Pathogenicity; Phagocytes; Pregnant Women; Prevalence; Procedures; Production; Property; Risk Assessment; Structure; TNF gene; Teichoic Acids; Therapeutic; Virulence; Virulent; Work; base; cell growth; cytokine; foodborne pathogen; improved; in vivo; indexing; killings; macrophage; monolayer; mutant; neonate; public health relevance; research study; sugar

DESCRIPTION (provided by applicant): Great strides have been made in understanding Listeria monocytogenes pathogenesis, especially at the cell biological level. One reason for this progress has been the extensive use of a single serogroup 1/2 L. monocytogenes strain, EGD. However, representative strains from other more prevalent serogroups, including serogroup 4, have remained understudied. Serogroup 4 strains constitute the preponderance of disease associated isolates from humans and other animals. Listerial serogroups are defined by their wall teichoic acid (WTA) structure. All listerial isolates have one of two fundamentally different WTA structures--those represented by the 1/2 serogroup structure and those represented by serogroup 4 structure. Recent independent studies indicate that certain alterations to serogroup 4 WTA composition are profoundly attenuating. In this proposal we examine the pathogenesis of a mouse oral virulent serogroup 4 strain. We have one specific aim: 1) Construct and characterize mutants that have altered serogroup 4 wall teichoic acid (WTA) composition. We will systematically alter the serogroup 4 WTA composition and correlate compositional changes to alterations in pathogenicity in vivo and in vitro. This aim has three objectives: (a) Mutant construction and biochemical characterization; allelic exchange will be employed to introduce in-frame deletion mutations into genes whose products are required for the generation of, and the proper substitution of the serogroup 4 WTA repeat unit. (b) Mutant characterization in vitro; intracellular growth and cell-to-cell spread will be assessed in cultured mouse enterocyte and macrophage monolayers. (c) Mutant characterization in vivo and ex vivo; the oral virulence of each mutant will be determined in infective index experiments that assess the degree of translocation of the mutants from the intestinal lumen. Additionally, the elicitation of inflammatory cell infiltrates, phagocytic killing by PMN and mononuclear phagocytes, and level of TNF production will be examined for each WTA mutant. Overall, we anticipate that our results will extend our knowledge of listerial pathogenesis in a highly relevant serogroup. Additionally, our results have the potential to impact national health policies and procedures in several areas. For example: (i) Risk assessment-a knowledge of how serogroup 4 WTA composition influences virulence could facilitate the development of simple lectin based assays to assess the need for product recalls in cases of listerial contamination. (ii) Diagnostics-a knowledge how WTA composition influences pathogenic potential and disease presentation could facilitate diagnosis, improve the specificity of diagnostic assays, and improve the power of epidemiological studies. (iii) Therapies--specific therapeutic strategies could expand treatment modalities (e.g., ones tailored to disrupt specific steps in WTA biosynthesis).

描述(由申请人提供)：在理解单核细胞增多性李斯特菌发病机制方面取得了很大进展，特别是在细胞生物学水平上。这一进展的一个原因是单一血清组1/2单核细胞增多性李斯特菌菌株EGD的广泛使用。然而，来自其他更流行的血清组的代表性菌株，包括第4血清组，仍未得到充分研究。血清群4菌株构成了来自人类和其他动物的疾病相关分离株的优势。李斯特菌血清群由其壁磷壁酸(WTA)结构定义。所有李斯特菌分离株都有两种根本不同的WTA结构之一--由1/2血清组结构代表的WTA结构和由血清组4结构代表的WTA结构。最近的独立研究表明，血清组4 WTA组成的某些变化正在深刻地减弱。在这项建议中，我们研究了一种小鼠口服毒力血清群4菌株的致病机制。我们有一个特定的目标：1)构建和鉴定改变了血清组4壁磷壁酸(WTA)组成的突变体。我们将系统地改变WTA血清组4的组成，并将其组成变化与体内和体外致病性的变化相关联。这一目标有三个目标：(A)突变株的构建和生化特性；将利用等位基因交换将框内缺失突变引入其产物产生所需的基因中，并适当替换血清组4WTA重复单位。(B)突变的体外特征；将在培养的小鼠肠细胞和巨噬细胞单层中评估细胞内生长和细胞到细胞的扩散。(C)突变株在体内和体外的特性；将通过感染指数试验确定每个突变株的口服毒力，以评估突变株从肠腔移位的程度。此外，还将检测每个WTA突变体对炎性细胞浸润的诱导性、PMN和单核吞噬细胞的吞噬杀伤作用以及肿瘤坏死因子的产生水平。总体而言，我们预计我们的结果将在一个高度相关的血清组中扩大我们对李斯特菌发病机制的了解。此外，我们的结果有可能影响几个领域的国家卫生政策和程序。例如：(I)风险评估-了解第4组WTA如何影响毒力，可促进开发基于凝集素的简单分析，以评估在李斯特菌污染情况下产品召回的必要性。(Ii)诊断学--关于WTA成分如何影响致病潜力和疾病表现的知识，可促进诊断，提高诊断分析的特异性，并提高流行病学研究的能力。(3)治疗--特定的治疗战略可以扩大治疗模式(例如，为扰乱WTA生物合成的具体步骤而量身定做的治疗模式)。