Salmonella chronic infection: Biofilm matrix factors and innate immune tolerance

沙门氏菌慢性感染：生物膜基质因子和先天免疫耐受

基本信息

批准号：
10319614
负责人：
JOHN S GUNN
金额：
$ 19.25万
依托单位：
RESEARCH INST NATIONWIDE CHILDREN'S HOSP
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-12-17 至 2023-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10319614
关键词：
Address Affect Animals Antibiotics Architecture Bacteria Bacterial Infections Biological Assay Carrier State Chemotaxis Cholelithiasis Chronic Clinical Complement DNA Data Dependence Development Disease Enteral Enterobacteriaceae Environment Gallbladder Gastroenteritis Goals Human Immune Immune Evasion Immune Tolerance Immune response Immune system Immunity Immunology procedure In Vitro Individual Infection Kenya Knowledge Life Link Maintenance Methods Microbial Biofilms Microscopy Modeling Molecular Morbidity - disease rate Mus Natural Immunity Organ Outcome Pathogenicity Phagocytes Polymers Polysaccharides Prevention Production Proteins Regulation Research Respiratory Burst Role Salmonella Salmonella typhi Salmonella typhimurium Site Structure Surface Systemic disease Techniques Therapeutic Typhoid Fever Work acute infection antimicrobial antimicrobial peptide chronic infection confocal imaging extracellular immune clearance immune function immunoregulation improved in vivo innate immune function innovation interest mortality mouse model mutant neutrophil novel therapeutics pathogen prevent residence response therapy development

项目摘要

PROJECT SUMMARY Salmonellae are Enterobacteriaceae that cause a spectrum of diseases in humans and animals, including enteric (typhoid) fever and gastroenteritis. Typhoid fever, caused primarily by Salmonella enterica serovar Typhi (S. Typhi), results in a life-threatening systemic disease that is annually responsible for significant morbidity and mortality worldwide. Approximately 5% of individuals infected with S. Typhi become chronic carriers with the gallbladder (GB) as the primary site of persistence. S. Typhi is a human-restricted pathogen, therefore asymptomatic carriers represent a critical reservoir for further spread of disease. We have demonstrated that gallstones (GSs) aid in the development and maintenance of GB carriage in a mouse model (utilizing S. Typhimurium, which causes a typhoid fever-like disease in mice) and in humans, serving as a substrate to which salmonellae attach and form a protective biofilm. Thus, biofilm formation is a key step in the establishment of carriers. Salmonella in biofilms are known to be recalcitrant to antibiotics and host immunity, presenting a challenge for traditional treatment methods. A hallmark of chronic S. Typhi infections is the production of extracellular polymeric substances (EPSs) which are integral to biofilm development on GSs. How the bacteria subvert innate immunity during early stages of biofilm development and establish chronic infections is not known. Immune escape likely involves EPS, but a complete understanding of the EPSs responsible for this function is not known. We hypothesize one or more EPS has a critical role in biofilm development and contributes to the chronic pathogenicity of S. Typhi biofilms via innate immune evasion. Identification of the essential EPS(s) will allow us to determine the mechanism of immune evasion, likely due to a combination of a physical barrier function and regulation of innate host responses. To build on our prelinminary data, we will further investigate which EPSs are responsible for this perturbation and conduct quantitative assays to evaluate innate phagocyte activity in response to WT and EPS mutant biofilms. Assays for soluable factors (e.g. antimicrobial peptides, complement) and polymorphonuclear cell (neutrophil) functions (chemotaxis, neutrophil extracellular trapping, and induction of respiratory burst) have been or will be conducted. Confocal imaging of EPSs from in vitro and in vivo GSs will determine the structural contribution of each EPS during chronic infection and will be correlated to functional assays of immune modulation. Overall, an improved understanding of how biofilms develop in vivo and how EPSs skew innate immunity will be critical for development of new treatment and prevention methods. Disruption of carrier state infections will have a significant impact on endemic S. Typhi persistence and the spread of typhoid fever.

项目概要沙门氏菌是肠杆菌科细菌，可引起人类和动物的一系列疾病，包括肠道疾病（伤寒）发烧和胃肠炎。伤寒，主要由伤寒沙门氏菌（S. 伤寒），导致一种危及生命的全身性疾病，每年导致严重的发病率和全球死亡率。大约 5% 的伤寒沙门氏菌感染者成为慢性携带者胆囊（GB）是主要的持续存在部位。伤寒沙门氏菌是一种人类限制性病原体，因此无症状携带者是疾病进一步传播的关键储存库。我们已经证明了胆结石 (GS) 有助于小鼠模型中 GB 运输的发育和维持（利用 S. 鼠伤寒菌，在小鼠和人类中引起类似伤寒的疾病，作为底物沙门氏菌附着并形成保护性生物膜。因此，生物膜的形成是建立生物膜的关键步骤。载体。众所周知，生物膜中的沙门氏菌对抗生素和宿主免疫具有抵抗力，这提出了挑战对于传统的治疗方法。慢性伤寒沙门氏菌感染的一个标志是细胞外聚合物的产生物质（EPS），是 GS 上生物膜形成不可或缺的一部分。细菌如何破坏先天免疫在生物膜形成的早期阶段和建立慢性感染尚不清楚。可能发生免疫逃逸涉及 EPS，但对负责此功能的 EPS 的完整了解尚不清楚。我们假设一种或多种 EPS 在生物膜形成中发挥关键作用，并导致伤寒沙门氏菌的慢性致病性通过先天免疫逃避形成生物膜。识别基本 EPS 将使我们能够确定其机制免疫逃避，可能是由于物理屏障功能和先天宿主反应调节的结合。为了以我们的初步数据为基础，我们将进一步调查哪些 EPS 造成了这种扰动，并进行定量测定以评估对 WT 和 EPS 突变生物膜的先天吞噬细胞活性。可溶性因子（例如抗菌肽、补体）和多形核细胞（中性粒细胞）的测定功能（趋化性、中性粒细胞胞外捕获和呼吸爆发的诱导）已经或将要实施。来自体外和体内 GS 的 EPS 的共焦成像将确定每个的结构贡献慢性感染期间的 EPS 将与免疫调节的功能测定相关。总体而言，改进了了解生物膜如何在体内发育以及 EPS 如何影响先天免疫对于发育至关重要新的治疗和预防方法。携带者状态感染的中断将对地方性伤寒沙门氏菌的持续存在和伤寒的传播。