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Iron and pathogenesis in infections by Vibrio vulnificus

铁与创伤弧菌感染的发病机制

基本信息

批准号：
8021857
负责人：
JORGE H CROSA
金额：
$ 37.02万
依托单位：
OREGON HEALTH & SCIENCE UNIVERSITY
依托单位国家：
美国
项目类别：
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/8021857
关键词：
Address Adhesions Affect Alcoholic Liver Diseases Amino Acids Bacteria Blood Circulation Cell Count Characteristics Chemotaxis Cirrhosis Disease Dissection 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 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

项目摘要

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（由申请方提供）：创伤弧菌是一种机会性人类病原体，能够引起致死性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症或其他潜在肝脏疾病如肝硬化和酒精性肝病的患者中。在大多数这些患者的共同主题是，铁是目前在高于生理水平。我们认为，创伤弧菌CMCP 6的基因调控取决于许多因素，这些因素取决于感染过程中环境条件的变化，即高铁、营养物质浓度和氧气可用性。在本申请中，我们提出解剖的具体机制，管理他们的表达在创伤弧菌，在体外和体内。实现这些目标的具体目的是：1）其表达受受损患者的培养基和/或人血清组分的铁浓度影响的基因的体外调节。在这个目标中，我们确定的因素，除了高铁浓度的血清中发挥作用的毒力基因的表达在患者血清中表达。2)分析HlyU，创伤弧菌在高和铁限制条件下表达的全局转录调节因子和毒力因子。我们证明，HlyU除了是一个重要的毒力因子，也是一个全球性的转录调节，在富铁和铁限制条件下控制许多毒力基因的表达，其中一些高度表达，只有在高铁条件。为此，我们建议使用纯化的HlyU蛋白的转录和翻译融合的组合以及凝胶迁移和DNA保护实验。3)创伤弧菌基因在两种不同小鼠模型中的体内表达的分析。在这个特定的目标，我们建议使用重组为基础的体内技术（RIVET），以确定创伤弧菌的基因，在体内特异性表达的铁超载的小鼠模型感染过程中相比，感染后诱导的正常小鼠。将通过诱变和毒力实验对使用两种小鼠模型以及体外鉴定的基因进行表征。因此，我们期望获得这种细菌在体内与体外生长相比的生理学的全面图片。这些研究将有助于加深对创伤弧菌感染的发病机制和细菌毒力的了解。