Contribution of catabolite control protein A to group A streptococcal virulence

分解代谢物控制蛋白 A 对 A 组链球菌毒力的贡献

• 批准号: 8692634
• 负责人: SAMUEL A SHELBURNE
• 金额: $ 31.6万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-15 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8692634
• 关键词: A-Form DNA; Address; Affect; Affinity; Bacillus (bacterium); Bacteria; Bacterial Genes; Bacterial Infections; Bacterial Physiology; Binding; Binding Sites; Bioinformatics; Carbon; Cessation of life; Consensus Sequence; DNA; DNA Binding; DNA Sequence; Data; Development; Disease; Eating; Environment; Future; Gene Expression; Gene Expression Profile; Gene Expression Profiling; Gene Expression Regulation; Genes; Goals; Gram-Positive Bacteria; Growth; Histidine; Human; In Vitro; Infection; Investigation; Laboratories; Metabolic; Methods; Modeling; Molecular Profiling; Mus; Muscle; Mutation; Myositis; Nature; Necrotizing fasciitis; Pathogenesis; Pathway interactions; Pharyngeal structure; Pharyngitis; Phosphoproteins; Phosphorylase Kinase; Physiological; Preventive Intervention; Production; Proteins; Recombinants; Research; Response Elements; Role; Serine; Serotyping; Site; Source; Stimulus; Streptococcal Infections; Streptococcus pyogenes; Testing; Transcript; United States; Virulence; Virulence Factors; base; defined contribution; design; genetic regulatory protein; in vivo; innovation; insight; mouse model; multiple myeloma M Protein; mutant; novel; novel therapeutic intervention; pathogen; pathogenic bacteria; response

DESCRIPTION (provided by applicant): Infections by Gram-positive bacteria cause tens of thousands of deaths in the United States each year. The transcriptional regulator catabolite control protein A (CcpA) has recently been found to influence the virulence gene expression profile during growth in standard laboratory medium of numerous Gram-positive pathogens including group A Streptococcus (GAS). CcpA was originally identified in Bacillus species where it binds DNA sequences termed catabolite response element (cre) sites in conjunction with its co-factor histidine-containing phosphoprotein phosphorylated at serine residue 46 (HPr-Ser46-P). Orthologues of CcpA, HPr, and the kinase/phosphorylase that regulates HPr phosphorlyation status (HPrK/P) are present in all major Gram- positive human pathogens, and there are accumulating data suggesting that the CcpA-(HPr-Ser46-P)-HPrK/P axis contributes to the infectivity of diverse bacterial species. The long term goals of this project are to clearly define how the CcpA-(HPr-Ser46-P)-HPrK/P axis contributes to GAS virulence and to ascertain mechanisms by which CcpA influences gene expression during infection. The specific aims of this proposal have been designed to test hypotheses arising from preliminary data demonstrating that: 1) Inactivation of CcpA altered GAS gene expression during infection in mouse muscle; 2) Inactivation of CcpA decreased GAS virulence in a mouse myositis model; 3) Mutation of the central CpG of a GAS cre site decreased CcpA-(HPr-Ser46-P) DNA binding affinity; and 4) CcpA influenced gene expression under conditions in which HPr-Ser46-P levels are low or absent. In aim 1, gene expression analysis of wild-type and CcpA-inactivated GAS strains will be performed in multiple mouse models of infection to test the hypothesis that CcpA is a key virulence factor regulator during GAS infection. In aim 2, the virulence of CcpA isogenic mutant strains derived from different M protein serotype parental strains will be compared to their parental wild-type strains in various mouse models of infection to test the hypothesis that CcpA positively contributes to the infectivity of GAS strains of multiple M protein serotypes. In aim 3, a combination of in vitro and in vivo methods will be used to test the hypothesis that the central cre site CpG is critical for the effect of CcpA on GAS gene expression. In aim 4, the gene expression profiles of CcpA and HPr-Ser46-P inactivated strains will be compared under different metabolic conditions to test the hypothesis that CcpA can affect GAS gene expression in the absence of HPr-Ser46-P. The highly conserved nature of the CcpA-(HPr-Ser46-P)-HPrK/P axis amongst major Gram-positive bacterial pathogens means that the successful completion of the proposed research may generate new insights into disease pathogenesis that are relevant to a broad array of pathogenic bacteria. Such information could form the basis for the development of novel therapeutic or preventive interventions.

描述（由申请人提供）：革兰氏阳性菌感染每年在美国造成数万人死亡。转录调节物分解代谢控制蛋白A （CcpA）最近被发现在标准实验室培养基中影响许多革兰氏阳性病原体（包括A群链球菌（GAS））生长过程中的毒力基因表达谱。CcpA最初是在芽孢杆菌中发现的，它与分解代谢反应元件（cre）位点的DNA序列结合，并与其在丝氨酸残基46位点磷酸化的辅助因子含组氨酸的磷酸化蛋白（HPr-Ser46-P）结合。CcpA、HPr和调节HPr磷酸化状态的激酶/磷酸化酶（HPrK/P）的同源物存在于所有主要的革兰氏阳性人类病原体中，并且越来越多的数据表明CcpA-(HPr- ser46 -P)-HPrK/P轴有助于多种细菌的传染性。该项目的长期目标是明确CcpA-(HPr-Ser46-P)- hprk /P轴如何促进GAS毒力，并确定CcpA在感染期间影响基因表达的机制。本提案的具体目的是为了验证从初步数据中产生的假设，这些数据表明：1)CcpA失活改变了小鼠肌肉感染期间GAS基因的表达；2) CcpA失活可降低小鼠肌炎模型中GAS的毒力；3) GAS中心位点的CpG突变降低了CcpA-(hrp - ser46 - p) DNA结合亲和力；4) CcpA在低或缺失HPr-Ser46-P水平下影响基因表达。在aim 1中，将在多种小鼠感染模型中进行野生型和CcpA灭活的GAS菌株的基因表达分析，以验证CcpA是GAS感染过程中关键毒力因子调节因子的假设。在目的2中，将不同M蛋白血清型亲本菌株衍生的CcpA等基因突变株与亲本野生型菌株在各种小鼠感染模型中的毒力进行比较，以验证CcpA对多种M蛋白血清型GAS菌株的传染性有积极作用的假设。在目标3中，将使用体外和体内方法相结合的方法来验证中心中心位点CpG对CcpA对GAS基因表达的影响至关重要的假设。在目的4中，我们将比较CcpA和hrp - ser46 - p灭活菌株在不同代谢条件下的基因表达谱，以验证CcpA在没有hrp - ser46 - p的情况下影响GAS基因表达的假设。CcpA-(hrp - ser46 -P)- hprk /P轴在主要革兰氏阳性细菌病原体中的高度保守性意味着该研究的成功完成可能会对与广泛致病菌相关的疾病发病机制产生新的见解。这些信息可以成为发展新的治疗或预防干预措施的基础。