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)：杜雷氏嗜血杆菌是一种严格的人类病原体，会引起下巴，这是一种生殖器溃疡疾病(GUD)，有助于人类免疫缺陷病毒(HIV-1)的传播。为了研究杜氏嗜血杆菌的生物学，我们开发了一个接近模拟自然感染的人类挑战模型。在感染过程中，杜氏杆菌在脓肿的恶劣环境中被发现，并抵抗吞噬作用。我们发现H.ducreyi对寄主有广泛的转录反应，这表明H.ducreyi对寄主环境有感知和响应。H.ducreyi只包含两个已知的响应胞外胁迫的系统：双组分调节因子CpxRA和另一种sigma因子RpoE。在脓疱疮中，CpxRA特异性效应物的几个H.ducreyi同源物上调，而RpoE特异性效应物的许多同源物下调，这表明CpxRA和RpoE系统在H.ducreyi中是相连的，并以一种协调的方式对宿主施加的压力做出反应。我们发现，CpxRA控制着杜氏嗜血杆菌几个主要毒力决定因素的表达，并且CpxRA的不受控制的激活削弱了机体感染人类志愿者的能力。我们假设杜氏杆菌通过CpxRA和RpoE感知宿主环境，CpxRA和RpoE在感染过程中都发挥作用，以对抗体内遇到的压力并控制毒力决定因素的产生，CpxRA或RpoE系统中具有结构性活性的表达产物或缺失突变体的毒力将减弱，已知或新的毒力决定因素在感染期间将受到CpxRA和RpoE的不同调控。为了验证这些假说，我们的具体目标包括：1)评估cpxR、rpoE、rseA和rseC缺失突变体和表达成分激活的cpxR和RpoE的菌株在人类志愿者中的毒力；2)在与人类感染相关的模型中确定CpxRA和RpoE系统在致病机制中的潜在机制(S)；3)鉴定由CpxRA和RpoE途径控制的新的毒力决定因素，并在体内(AIM1)和体外(AIM 2)模型中评估它们在感染中的作用。我们的建议提供了一个独特的机会来研究两个相互关联的应激反应系统对人类病原体生存的贡献，将导致识别新的毒力决定因素，并已经导致了新的抗微生物策略的开发。经NIAID批准，此次修订的目的是获得资金，以支持与资助申请的目标1和目标3相关的人类接种实验。 与公共卫生相关：杜雷氏嗜血杆菌是一种细菌，可引起生殖器溃疡疾病，促进艾滋病毒传播。当杜氏杆菌感染人类宿主时，它会启动许多基因的表达。我们的研究旨在研究H.ducreyi如何使用应激反应系统来适应人类宿主。杜氏杆菌只被三种抗生素杀死，是开发新疗法的高度优先生物。该项目应该产生针对杜氏杆菌和其他细菌感染的疫苗或替代疗法的目标。