Iron and pathogenesis in infections by Vibrio vulnificus

铁与创伤弧菌感染的发病机制

• 批准号: 7266517
• 负责人: JORGE H CROSA
• 金额: $ 38.46万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-01 至 2012-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7266517
• 关键词: Address; Adhesions; Affect; Alcoholic Liver Diseases; Amino Acids; Bacteria; Blood Circulation; Cell Count; Characteristics; Chemotaxis; Cirrhosis; Condition; Disease; Dissection; Endopeptidases; Factor V; Flagella; Gel; Gene Expression Regulation; Genes; Genetic Recombination; Genetic Transcription; Goals; Growth; Hemochromatosis; Human; Immunocompromised Host; In Vitro; Infection; Iron; Iron Overload; Laboratories; Lead; Liver Cirrhosis; Liver diseases; Microarray Analysis; Microbial Biofilms; Modeling; Mus; Mutagenesis; Mutation; Nutrient; Organ; Oxygen; Pathogenesis; Pathogenicity; Pathology; Patients; Peptide Hydrolases; Physiological; Physiology; Play; Polymerase Chain Reaction; Process; Production; Proteins; RNA; Regulator Genes; Reporting; Research; Research Personnel; Reverse Transcriptase Polymerase Chain Reaction; Role; Septicemia; Serum; Siderophores; Starvation; Techniques; Technology; Time; Validation; Vibrio vulnificus; Virulence; Virulence Factors; Wound Infection; base; capsule; cell motility; cytotoxicity; in vivo; indexing; interest; mouse model; mutant; pathogen; programs; rapid growth; research study; vulnibactin

DESCRIPTION (provided by applicant): Vibrio vulnificus is an opportunistic human pathogen capable of causing fatal primary septicemias or necrotizing wound infections. Septicemia occurs in patients that are immunocompromised or suffering from hemochromatosis or with other underlying liver disorders such as cirrhosis and alcoholic liver disease. The common theme in most of these patients is that iron is present at higher than physiological level. We believe that gene regulation of V. vulnificus CMCP6 depends on many factors according to the changes in environmental conditions i.e. high iron, nutrients concentration, and oxygen availability during the process of infection. In this application we propose to dissect the specific mechanisms that govern their expression in V. vulnificus, in vitro and in vivo. The specific aims to achieve these goals are: 1) In vitro regulation of genes whose expression is affected by the iron concentration of the medium and/or components of human serum of compromised patients. In this aim we identify factors in addition to the high iron concentration of the serum play a role in the expression of virulence genes expressed in patient sera. 2) Analysis of HlyU, a global transcription regulator and virulence factor of V. vulnificus expressed at both high and iron limiting conditions. We demonstrate that HlyU in addition to being an important virulence factor is also a global transcriptional regulator that at both iron-rich and iron limiting conditions controls the expression of many virulence-genes, some of them highly expressed only at high iron conditions. In this aim we propose to use a combination of transcriptional and translational fusions as well as gel shift and DNAsel protection experiments with the purified HlyU protein. 3) Analysis of the in vivo expression of V. vulnificus genes in two different mouse models. In this specific aim we propose to use recombination-based in vivo technology (RIVET) to identify V. vulnificus genes that are expressed specifically in vivo during infection of the iron-overloaded mouse model as compared to those induced after infecting the normal mouse. The genes identified using both mouse models as well as those identified in vitro will be characterized by mutagenesis and virulence experiments. Thus, we expect to obtain a comprehensive picture of the physiology of this bacterium during in vivo as compared to in vitro growth. These studies will lead to an enhanced understanding of the pathogenesis of V. vulnificus infections in particular and of bacterial virulence in general.

描述（由申请人提供）：创伤弧菌是一种机会性人类病原体，能够引起致命的原发性败血症或坏死性伤口感染。败血症发生在免疫功能低下或患有血色素沉着病或患有其他潜在肝脏疾病（例如肝硬化和酒精性肝病）的患者中。大多数这些患者的共同主题是铁含量高于生理水平。我们认为，创伤弧菌CMCP6的基因调控取决于许多因素，根据环境条件的变化，即感染过程中的高铁、营养物浓度和氧气可用性。在本申请中，我们建议在体外和体内剖析控制它们在创伤弧菌中表达的具体机制。实现这些目标的具体目标是： 1) 其表达受受损患者的培养基中的铁浓度和/或人血清成分影响的基因的体外调节。为此，我们确定了除血清高铁浓度之外的因素在患者血清中表达的毒力基因的表达中发挥作用。 2) HlyU 的分析，HlyU 是创伤弧菌的一种全局转录调节因子和毒力因子，在高铁限制条件下表达。我们证明，HlyU 除了是一种重要的毒力因子之外，还是一种全局转录调节因子，在富铁和铁限制条件下控制许多毒力基因的表达，其中一些仅在高铁条件下高度表达。为此，我们建议对纯化的 HlyU 蛋白结合使用转录和翻译融合以及凝胶迁移和 DNAsel 保护实验。 3）两种不同小鼠模型中创伤弧菌基因的体内表达分析。在这个具体目标中，我们建议使用基于重组的体内技术（RIVET）来鉴定创伤弧菌基因，这些基因在铁超载小鼠模型感染期间与感染正常小鼠后诱导的基因相比在体内特异性表达。使用小鼠模型以及体外鉴定的基因将通过诱变和毒力实验来表征。因此，我们期望获得该细菌在体内与体外生长期间的生理学的全面了解。这些研究将有助于加深对创伤弧菌感染的发病机制和一般细菌毒力的了解。