Analysis of the virulence mechanism of a lantibiotic locus

羊毛硫抗生素基因座的毒力机制分析

• 批准号: 7754869
• 负责人: MELODY Neuhart NEELY
• 金额: $ 17.78万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-05 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7754869
• 关键词: Animal Model; Antibiotic Therapy; Attenuated; Biological Assay; Cells; Clinical Treatment; Communities; Data; Disease; Disease Progression; Disease model; Elements; Environment; Genes; Goals; Growth; Healthcare Systems; Host Defense Mechanism; Human; Immune; Immune response; Immune system; In Vitro; Individual; Infection; Knowledge; Lead; Life; Medical; Modeling; Operon; Organism; Outcome; Pathogenesis; Peptides; Phagocytes; Phagocytosis; Pharyngitis; Plasmids; Predisposition; Production; Promoter Regions; Proteins; Research; Role; Site; Streptococcus pyogenes; Testing; Tissues; Vertebrates; Virulence; Virulence Factors; Work; Zebrafish; antimicrobial; extracellular; fighting; human disease; in vivo; infectious disease model; innovation; insight; macrophage; mutant; neutrophil; overexpression; pathogen; permease; public health relevance; response; sal protein; salivaricin A; tissue culture

DESCRIPTION (provided by applicant): The recent increase in S. pyogenes invasive disease emphasizes the ability of this organism to acquire new survival strategies that allow dissemination and growth in previously uninhabitable sites. Despite enormous research efforts, a clear picture does not exist as to how a disease progresses from a self-limiting superficial infection to the condition of invasive disease, or how S. pyogenes can circumvent the battery of host defense mechanisms in multiple tissues during an invasive infection. In order to identify specific virulence determinants for invasive disease, we have developed an animal model of invasive disease using the zebrafish (Danio rerio). Three mutants with random insertions in separate genes of the salivaricin A lantibiotic locus were identified as being attenuated in the zebrafish invasive disease model. One of these mutants is also deficient in intracellular survival in macrophages. While several mechanisms have been identified for evasion of phagocytosis by S. pyogenes, not much is known about how a typically extracellular pathogen can survive in the intracellular environment. Our long-range goal is to define host-pathogen interactions during an infection that lead to activation of virulence mechanisms and invasive streptococcal disease. The objective of the current application is to characterize the virulence mechanism of a locus in S. pyogenes that allows the pathogen to subvert the innate immune system and cause invasive disease. The central hypothesis of the proposed research is: the function of the S. pyogenes salivaricin locus has evolved from lantibiotic production to a mechanism of virulence and survival during an infection. We plan to test our central hypothesis and accomplish the overall objective of this application by pursuing the following specific aims: 1) identify which proteins encoded by the sal operon are important for virulence; 2) identify the mechanism of the SalY permease in virulence; and 3) identify the role of the sal operon in intracellular survival. Collectively, these outcomes will provide new information on how S. pyogenes has evolved to survive elements of the innate immune system and contribute to disease progression as well as identify new targets for antimicrobial therapy. PUBLIC HEALTH RELEVANCE: Streptococcal pathogens are remarkably efficient at causing disease, providing a major challenge to the medical community and an enormous financial burden to our health care system. The research described in this proposal will identify how these pathogens have developed ways in which to avoid the immune system during infection. Confirmation of these mechanisms will have direct relevance to human disease and clinical treatment.

描述（由申请人提供）：化脓性链球菌侵入性疾病的最新增加强调了该生物获得新的生存策略的能力，该策略允许以前无法居住的地点传播和增长。尽管进行了巨大的研究工作，但对于疾病如何从自限制的表面感染到侵袭性疾病的状况，或者在侵入性感染期间如何绕开多个组织中多种组织中的宿主防御机制的电池。为了确定侵入性疾病的特定毒力决定因素，我们使用斑马鱼（Danio Rerio）开发了一种侵入性疾病的动物模型。三个突变体在唾液素A型唾液酸基因座的单独基因中随机插入的突变体被确定为在斑马鱼入侵性疾病模型中减弱。这些突变体之一也缺乏巨噬细胞的细胞内存活率。虽然已经确定了多种化脓性链球菌逃避吞噬作用的机制，但对于典型的细胞外病原体如何在细胞内环境中生存并不了解。我们的远程目标是在感染过程中定义宿主 - 病原体相互作用，从而导致毒力机制激活和侵入性链球菌疾病。当前应用的目的是表征链球菌中一个基因座的毒力机制，该机制使病原体可以颠覆先天的免疫系统并引起侵入性疾病。拟议的研究的中心假设是：唾液酸葡萄球菌基因链球菌的功能已从甘丙酰生物的产生演变为感染过程中毒力和生存的机制。我们计划通过追求以下特定目的来检验我们的中心假设，并实现本应用的整体目标：1）确定由SAL操纵子编码的哪种蛋白质对毒力很重要； 2）确定毒力中咸渗透酶的机制； 3）确定SAL操纵子在细胞内存活中的作用。总的来说，这些结果将提供有关链球菌如何演变为生存的新信息，以生存先天免疫系统的元素，并有助于疾病进展，并确定抗菌治疗的新靶标。 公共卫生相关性：链球菌病原体在引起疾病方面非常有效，对医疗界带来了重大挑战，并给我们的医疗保健系统带来了巨大的财务负担。该提案中描述的研究将确定这些病原体如何开发出在感染过程中避免免疫系统的方法。这些机制的确认将与人类疾病和临床治疗有直接相关。