S. pneumoniae pilus regulation and host response

肺炎链球菌菌毛调节和宿主反应

• 批准号: 8893197
• 负责人: RICHARD MALLEY
• 金额: $ 64.91万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2017-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8893197
• 关键词: Accounting; Adherence; Affect; Agonist; Animal Model; Bacteria; Bacterial Adhesins; Bacterial Genes; Cells; Cessation of life; Child; Childhood; Clinical; Collaborations; Columbidae; Complex; Conjugate Vaccines; Costs and Benefits; Country; DNA-Directed RNA Polymerase; Disease; Epidemiology; Escherichia coli; Evaluation; Family; Family member; Feedback; Fimbriae Proteins; Flow Cytometry; Frequencies; Gene Expression; Gene Expression Regulation; Genes; Genetic; Gram-Positive Bacteria; Growth; Health; Human; Immune; Immune response; Immunologic Receptors; Immunology; In Vitro; Individual; Investigation; Knowledge; Laboratories; Life; Mediating; Microbial Biofilms; Molecular; Molecular and Cellular Biology; Mus; Nasopharynx; Organism; Orthologous Gene; Pathogenesis; Pilum; Play; Pneumococcal conjugate vaccine; Population; Prevalence; Process; Property; Protein Family; Proteins; Public Health; Regulation; Regulator Genes; Regulatory Pathway; Reporter; Research; Role; SWI2/SNF2; Serotyping; Source; Streptococcus pneumoniae; Structure; System; Techniques; Temperature; Time; Toll-Like Receptor 2; Vaccines; Virulence; Virulence Factors; cost; fitness; gene discovery; helicase; in vivo; insight; islet; member; mouse model; mutant; pilus genes; protein protein interaction; research study; success

DESCRIPTION (provided by applicant): The overall objective of the proposed research is to evaluate the gene regulatory pathway of the pneumococcal type 1 pilus and the interaction between the pilus and the innate and acquired immune responses. The type 1 pilus of S. pneumoniae is encoded by a small number of genes present in a subset of clinical strains. In the course of studies on the role of the type I pilus in virulence, the Malley and Dove laboratories jointly discovered that the genes encoding this pilus are bistably expressed, that the structural pilus protein RrgA acts as a negative regulator of pilus expression by inhibiting the positive regulator RlrA through a direct protein-protein interaction and that the pneumococcal type I pilus is controlled by a feedback- mediated bistable switch comprised of RlrA. Additionally, we have shown that RrgA is a potent activator of the innate immune receptor Toll-like receptor 2. Most recently, in trying to dissect the complex regulatory pathways of pilus gene expression, we uncovered a role for temperature in the control of type I pilus gene expression. We have also found that this silencing of pilus gene expression is dependent upon SP_1523, a protein that belongs to the HepA/RapA family. Our findings represent the first demonstration of a role of this conserved family of proteins in gene regulation. The complexity of the regulatory mechanisms of pilus expression and the interaction with an immune receptor raise the possibility that an intricate relationship between the bacterial structure and the host modulates the expression of the pilus. Here we propose to evaluate these issues further, by a combination of various approaches, including a thorough evaluation of how type 1 pilus genes are regulated by SP_1523 (Aim 1), and an in vivo analysis of the interaction between SP_1523, pilus expression, innate and acquired immune responses, using mutant, reporter and constitutively-expressing strains (Aim 2). Overall, these investigations will provide important insights into the mechanisms of gene regulation that may be applicable not only to S. pneumoniae but also to other bacteria, and also elucidate how the immune response to such tightly regulated genes may modify the selective advantages in colonization.

描述（由申请人提供）：拟议研究的总体目标是评价1型肺炎球菌菌毛的基因调控途径以及菌毛与先天性和获得性免疫应答之间的相互作用。S.肺炎克雷伯氏菌由存在于临床菌株亚群中的少量基因编码。在研究I型菌毛在毒力中的作用的过程中，Malley和Dove实验室联合发现，编码这种菌毛的基因是双稳态表达的， 结构菌毛蛋白RrgA通过直接的蛋白质-蛋白质相互作用抑制正调节因子RlrA而起菌毛表达的负调节因子的作用，并且肺炎球菌I型菌毛受由RlrA组成的反馈介导的转录开关控制。此外，我们已经证明RrgA是先天免疫受体Toll样受体2的有效激活剂。最近，在试图剖析菌毛基因的复杂调控途径时， 表达，我们发现了温度在控制I型菌毛基因表达中的作用。我们还发现，这种菌毛基因表达的沉默取决于SP_1523，一种属于HepA/RapA家族的蛋白质。我们的研究结果代表了这个保守的蛋白质家族在基因调控中的作用的第一个证明。菌毛表达的调控机制的复杂性和与免疫受体的相互作用提高了细菌结构和宿主之间的复杂关系调节菌毛表达的可能性。在这里，我们建议进一步评估这些问题，通过各种方法的组合，包括1型菌毛基因是如何调节SP_1523（目标1），和SP_1523，菌毛表达，先天性和获得性免疫反应之间的相互作用的体内分析，使用突变体，报告和组成型表达菌株（目标2）的彻底评估。总的来说，这些研究将提供重要的见解基因调控的机制，可能不仅适用于S。肺炎，但也对其他细菌，也阐明了如何免疫反应，这种严格调控的基因可能会修改选择性优势的殖民。