Pathogenic mechanisms of non-01/non-0139 V. cholerae

非01/非0139霍乱弧菌的致病机制

• 批准号: 7631195
• 负责人: MICHELLE DZIEJMAN
• 金额: $ 38.5万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-06-15 至 2013-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7631195
• 关键词: Actins; Africa; Animal Model; Area; Asia; Attenuated; Biological Assay; Biological Models; Bioterrorism; Categories; Cell Communication; Cell physiology; Cells; Centers for Disease Control and Prevention (U.S.); Cholera; Cholera Toxin; Country; Cyclic Nucleotides; Cytoskeletal Modeling; Cytosol; Data; Developed Countries; Developing Countries; Disease; Epidemic; Eukaryotic Cell; Experimental Designs; Filopodia; Food; Gene Expression; Genes; Genetic; Genomics; Goals; Growth; Health; In Vitro; Individual; Infant; Infection; Intestines; Investigation; Island; Mammalian Cell; Mediating; Molecular; Mus; Names; Open Reading Frames; Oryctolagus cuniculus; PAWR protein; Pathogenesis; Pathogenicity Island; Phenotype; Pilum; Production; Proteins; Research Infrastructure; Ribotypes; Ribotyping; Role; Saccharomyces cerevisiae; Sanitation; Signal Pathway; South America; Structure; Structure-Activity Relationship; System; Toxin; Transcription Regulatory Protein; Travel; United States; Vibrio cholerae; Vibrio cholerae O139; Vibrio parahaemolyticus; Virulence; Virulence Factors; War; Water; Yeasts; Yersinia; cellular targeting; comparative; cytotoxicity; experience; genome sequencing; in vivo; in vivo Model; mouse model; mutant; novel; pandemic disease; pathogenic bacteria; protein expression; research study; rho

DESCRIPTION (provided by applicant): Vibrio cholerae is the causative agent of the severe diarrheal disease, cholera, that is endemic in much of Asia, Africa, and South America. The species is quite diverse, although only strains of the O1 or O139 serogroup cause epidemic disease. However, a significant amount of disease occurs globally in sporadic episodes and is caused by strains belonging to non-O1/non-O139 serogroups. Unlike pathogenic O1 and O139 strains, the vast majority of pathogenic non-O1/non-O139 strains do not carry the well characterized virulence factors for colonization (TCP) and toxin production (CT), and presumably cause disease by an unknown mechanism(s). Whole genome sequencing of a clinically isolated non-O1/non-O139 strain, AM-19226, has revealed the presence of open reading frames (ORFs) having significant similarity to genes encoding a Type Three Secretion System (TTSS). These ORFs appear to be conserved among a subset of non-O1/non-O139 strains, as well as pandemic strains of V. parahaemolyticus. Many pathogenic bacteria use TTSSs to translocate virulence factors into the cytosol of host cells, and we hypothesize that the presence of similar ORFs in V. cholerae represents a newly identified mechanism for host cell interaction and virulence acquired by these strains. Experiments suggest that the TTSS is indeed functional and has a role in pathogenesis. Deletion of a critical component of the TTSS severely attenuates the ability of strain AM-19226 to colonize the infant mouse model. Furthermore, an effector protein (whose secretion is TTSS dependent) has been identified, and it appears to have a role in the reorganization of host cell actin. We propose to use three complimentary in vitro approaches to begin to understand TTSS mediated pathogenesis in V. cholerae. The first approach is to identify additional effector proteins that promote virulence, using complimentary in vitro and in vivo model systems. The second approach is to dissect how effector proteins interact with host cells at the molecular level to cause disease, and the third is to use genomic approaches to begin to understand the regulatory network governing expression of the genes encoding effector proteins and the TTSS structural apparatus. Project Narrative: Today cholera is considered a health threat mainly in developing nations, regions lacking modern sanitation facilities, and in countries experiencing disrupted civil infrastructure due to war or environmental crises. The disease poses a threat to individuals traveling to endemic areas, and the United States CDC considers some strains a Category B level BioTerrorism threat because of the potential for spread via contaminated food or water. While O1 and O139 epidemic causing strains are well studied, this proposal seeks to understand the virulence mechanisms employed by strains of other serogroups that represent an emerging threat.

描述（由申请人提供）：霍乱弧菌是严重腹泻病霍乱的病原体，霍乱在亚洲、非洲和南美洲的大部分地区流行。尽管只有 O1 或 O139 血清群的菌株引起流行病，但该物种相当多样化。然而，大量疾病在全球范围内零星发生，并且是由属于非 O1/非 O139 血清群的菌株引起的。与致病性 O1 和 O139 菌株不同，绝大多数致病性非 O1/非 O139 菌株不携带明确定植 (TCP) 和毒素产生 (CT) 的毒力因子，并且可能通过未知机制引起疾病。对临床分离的非 O1/非 O139 菌株 AM-19226 进行全基因组测序，发现存在与编码三型分泌系统 (TTSS) 的基因具有显着相似性的开放阅读框 (ORF)。这些 ORF 似乎在非 O1/非 O139 菌株以及副溶血性弧菌的大流行菌株中是保守的。许多病原菌利用 TTSS 将毒力因子转移到宿主细胞的细胞质中，我们假设霍乱弧菌中类似 ORF 的存在代表了一种新发现的宿主细胞相互作用和这些菌株获得毒力的机制。实验表明 TTSS 确实具有功能并在发病机制中发挥作用。删除 TTSS 的一个关键成分会严重削弱菌株 AM-19226 在幼年小鼠模型中定殖的能力。此外，还鉴定了一种效应蛋白（其分泌依赖于 TTSS），并且它似乎在宿主细胞肌动蛋白的重组中发挥作用。我们建议使用三种互补的体外方法来开始了解 TTSS 介导的霍乱弧菌发病机制。第一种方法是使用互补的体外和体内模型系统来识别促进毒力的其他效应蛋白。第二种方法是剖析效应蛋白如何在分子水平上与宿主细胞相互作用从而导致疾病，第三种方法是使用基因组方法开始了解控制效应蛋白编码基因和 TTSS 结构装置表达的调控网络。项目叙述：如今，霍乱被认为是一种健康威胁，主要发生在发展中国家、缺乏现代卫生设施的地区以及因战争或环境危机而民用基础设施遭到破坏的国家。这种疾病对前往流行地区旅行的个人构成威胁，美国疾病预防控制中心将某些菌株视为 B 级生物恐怖主义威胁，因为它们有可能通过受污染的食物或水传播。虽然 O1 和 O139 流行菌株已得到充分研究，但该提案旨在了解代表新兴威胁的其他血清群菌株所采用的毒力机制。