Pathogenesis of Haemophilus Ducreyi Infections

杜克雷嗜血杆菌感染的发病机制

• 批准号: 8238075
• 负责人: Stanley M. Spinola
• 金额: $ 11.34万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-05 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8238075
• 关键词: Abscess; Adhesions; Adult; Antibiotics; Attenuated; Bacteria; Bacterial Genes; Bacterial Infections; Bacteriophages; Biology; Collagen; Development; Disease; Down-Regulation; Enteral; Enterobacteriaceae; Environment; Evaluation; Fibrinogen; Funding; Genes; Genital system; Genome; Gram-Negative Bacteria; Growth; HIV; HIV-1; Hemoglobin; Hemophilus ducreyi; Histopathology; Homologous Gene; Human; Human Volunteers; In Vitro; Infection; Laboratories; Lead; Lesion; Link; Membrane; Modeling; National Institute of Allergy and Infectious Disease; Organism; Oxidative Stress; Pathogenesis; Pathway interactions; Phagocytosis; Phosphoric Monoester Hydrolases; Phosphotransferases; Play; Production; Proteins; Relative (related person); Reporter; Resistance; Role; Serum; Shock; Sigma Factor; Signal Transduction; Simulate; Skin; Staging; Stress; System; Testing; Time; Ulcer; Upper arm; Vaccines; Virulence; alternative treatment; antimicrobial; antimicrobial peptide; bactericide; biological adaptation to stress; blind; combat; design; in vivo; inorganic phosphate; killings; macrophage; mutant; novel; pathogen; periplasm; protein transport; research study; response; transmission process; uptake; volunteer

DESCRIPTION (provided by applicant): Haemophilus ducreyi is a strict human pathogen that causes chancroid, a genital ulcer disease (GUD) that facilitates the transmission of the human immunodeficiency virus (HIV-1). To study the biology of H. ducreyi, we developed a human challenge model that closely simulates natural infection. During infection, H. ducreyi is found in the hostile environment of an abscess and resists phagocytosis. We found that H. ducreyi had a broad transcriptional response to the host, suggesting that H. ducreyi senses and responds to the host environment. H. ducreyi contains only two systems known to respond to extracytoplasmic stress: the 2- component regulator CpxRA and the alternative sigma factor, RpoE. Several H. ducreyi homologues of CpxRA-specific effectors were upregulated, while many homologues of RpoE-specific effectors were downregulated in pustules, suggesting that that CpxRA and RpoE systems are linked in H. ducreyi and function in a coordinated fashion to respond to stresses mounted by the host. We found that CpxRA controlled the expression of several major virulence determinants of H. ducreyi and that uncontrolled activation of CpxRA impaired the ability of the organism to infect human volunteers. We hypothesize that H. ducreyi senses the host environment via CpxRA and RpoE, that both CpxRA and RpoE function during infection to combat stresses encountered in vivo and control the production of virulence determinants, that constitutively active expressers or deletion mutants in the CpxRA or RpoE systems will be attenuated for virulence and that known or novel virulence determinants will be differentially regulated by CpxRA and RpoE during infection. To test these hypotheses, our specific aims include: 1) evaluation of cpxR, rpoE, rseA and rseC deletion mutants and strains that express constitutively activated CpxR and RpoE for virulence in human volunteers; 2) determination of the mechanism(s) underlying the contributions of the CpxRA and RpoE systems to pathogenesis in models relevant to human infection; 3) identification of novel virulence determinants controlled by the CpxRA and RpoE pathways and evaluation of their role in infection in the in vivo (Aim1) and in vitro (Aim 2) models. Our proposal offers the unique opportunity to study the contributions of two interrelated stress response systems to the survival of a pathogen in humans, will lead to the identification of novel virulence determinants, and has already led to the development of a novel antimicrobial strategy. As approved by NIAID, the purpose of this revision is to obtain funds to support the human inoculation experiments related to Aims 1 and 3 of the funded application. PUBLIC HEALTH RELEVANCE: Haemophilus ducreyi is a bacterium that causes a genital ulcer disease that facilitates HIV transmission. H. ducreyi turns on the expression of many of its genes when it infects the human host. Our study is designed to examine how H. ducreyi uses stress response systems to adapt to the human host. H. ducreyi is only killed by three classes of antibiotics and is a high priority organism for the development of new therapies. This project should yield targets of vaccines or alternative treatments for H. ducreyi and other bacterial infections.

描述（由申请人提供）：嗜血杆菌是一种严格的人类病原体，导致牙冠（一种生殖器溃疡（GUD）），可促进人类免疫缺陷病毒（HIV-1）的传播。为了研究H. ducreyi的生物学，我们开发了一个人类挑战模型，该模型紧密模拟了自然感染。在感染过程中，在脓肿的敌对环境中发现了杜克里氏菌，并抵抗吞噬作用。我们发现，杜克里（H. ducreyi）对宿主的转录反应广泛，表明杜克里（H. ducreyi）感官并对宿主环境做出了反应。 H. ducreyi仅包含两个已知的系统来响应外胞质应力：2-组件调节剂CPXRA和替代Sigma因子RPOE。 CPXRA特异性效应子的几个H. dicreyi同源物上调，而脓疱中RPOE特异性效应子的许多同源物被下调，这表明CPXRA和RPOE系统在H. ducreyi中链接在H. ducreyi中，并以协调的方式响应压力，以应对压力。由主机。我们发现CPXRA控制了杜克里氏菌的几种主要毒力决定因素的表达，并且不受控制的CPXRA激活损害了生物体感染人类志愿者的能力。我们假设H. ducreyi通过CPXRA和RPOE感知宿主环境，在感染过程中CPXRA和RPOE功能都可以打击体内遇到的应力并控制毒力决定因素的产生，这些决定因素（在CPXRA或RPOE Systems中具有组成性活跃的表达者或删除）在感染期间，CPXRA和RPOE会因毒力而减弱，并且已知或新颖的毒力决定因素将受到差异性调节。为了检验这些假设，我们的具体目的包括：1）评估CPXR，RPOE，RSEA和RSEC缺失突变体以及菌株，这些突变体表达了组成型激活的CPXR和RPOE在人类志愿者中的毒力； 2）确定CPXRA和RPOE系统对与人类感染相关的模型中的发病机理的贡献的基础机制； 3）鉴定由CPXRA和RPOE途径控制的新型毒力决定因素，并评估其在体内（AIM1）和体外（AIM 2）模型中感染中的作用。我们的建议提供了独特的机会来研究两个相互关联的应力反应系统对人类病原体生存的贡献，将导致鉴定出新的毒力决定因素，并且已经导致了一种新型的抗菌策略的发展。正如NIAID批准的那样，此修订的目的是获得资金来支持与资助应用程序的目标1和3相关的人类接种实验。 公共卫生相关性：嗜血杆菌Ducreyi是一种引起生殖器溃疡疾病的细菌，可促进HIV传播。 H. ducreyi感染了人类宿主时，其许多基因的表达。我们的研究旨在研究H. ducreyi如何使用压力响应系统适应人类宿主。 H. ducreyi仅被三类抗生素杀死，是开发新疗法的高优先级生物。该项目应产生疫苗或其他细菌感染的疫苗或替代治疗方法。