Control of Pseudomonas aeruginosa Quorum Sensing and Alginate

铜绿假单胞菌群体感应和藻酸盐的控制

• 批准号: 8240832
• 负责人: Michael John Schurr
• 金额: $ 19.82万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2014-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8240832
• 关键词: Acute; Alginates; Alleles; Antibiotic Resistance; Burn injury; Chromosomes; Chronic; Cyanides; Cystic Fibrosis; Data; Development; Gene Activation; Genes; Genetic Transcription; Goals; Growth; Immune; Immune system; In Vitro; Individual; Infection; Lung; Maintenance; Mediating; Microbial Biofilms; Modeling; Morbidity - disease rate; Mus; Natural Immunity; Organism; Outcome; Pathogenesis; Pathway interactions; Patients; Phosphorylation; Pilum; Preventive; Property; Pseudomonas; Pseudomonas aeruginosa; Publishing; Pyocyanine; Rattus; Regulatory Pathway; Regulon; Repression; Research; Role; Septicemia; Signal Transduction; Staging; System; Testing; Therapeutic; Therapeutic Intervention; Transplant Recipients; Transplantation; Virulence; Virulence Factors; Work; base; cell motility; cystic fibrosis patients; improved; innovation; mortality; mucoid; novel strategies; pathogen; quorum sensing; response; rhamnolipid; therapeutic target

DESCRIPTION (provided by applicant): Pseudomonas aeruginosa is a ubiquitous, opportunistic pathogen primarily infecting individuals with a compromised immune system, including transplant patients; severe burn patients, and those with cystic fibrosis (CF). In the context of CF, P. aeruginosa establishes a chronic condition whose morbidity and mortality results from lung damage. Due to the uncanny antibiotic resistance, CF patients infected with Pseudomonas often have chronic infections with limited therapeutic options. Therefore, for improved efficacy in treatment, a basic understanding of the pathogenic mechanisms utilized by this organism needs to be examined for possible therapeutic targets. While a majority of previous studies have focused on the initial stages of colonization and infection, we propose a new approach in searching for treatments. Mounting evidence indicates that a biofilm mode of growth is most likely involved in P. aeruginosa pathogenesis. Many virulence factors are produced by P. aeruginosa under this growth condition including alginate, rhamnolipids, type IV pili and cyanide. Others and we have discovered that a response regulator AlgR, controls all of these virulence factors. We discovered that AlgR is required for biofilm formation and that it represses the Rhl quorum sensing system in a biofilm. We have most recently created an algR allele that is constitutively active, algRD54E. PAO1 harboring algRD54E on the chromosome is defective in biofilm formation and does not produce pyocyanin. Our data show two new roles for AlgR: (i) AlgR is able to repress and activate genes when it is constitutively "on" and; (ii) AlgR is controlling the Rhl quorum sensing system of P. aeruginosa. The proposed research is innovative because we are examining the role of quorum sensing in mucoid P.a.. The proposed research is also innovative because we are determining the mechanism for a transcriptional regulator that regulates five different virulence factors and can activate transcription when it is either phosphorylated or unphosphorylated. The hypothesis to be tested is: AlgR controls the Rhl quorum sensing system in mucoid P.a., thus allowing the organism to persist in chronic infections. We will test this hypothesis with two specific aims: 1) We will determine the mechanism of AlgR control on the Rhl QS system in in vitro P.a. biofilm formation and 2) We will determine the mechanism of AlgR control on the Rhl QS system in P.a. virulence. PUBLIC HEALTH RELEVANCE: Pseudomonas aeruginosa (P.a.) is an opportunistic pathogen primarily infecting immune compromised individuals, including transplant, severe burn, and cystic fibrosis (CF) patients. CF patients infected with Pseudomonas often have limited therapeutic options due to natural and selected antibiotic resistance of this organism. Our recent published research indicates that the regulatory system used to control alginate also controls a larger signaling system (the quorum sensing system) that stimulates many virulence determinants in P.a.. We will examine the effects of this regulatory cascade in a rat lung infection model. We anticipate that results from this work will decrease P.a. virulence and potentially aid in treatment of P.a. chronic infections.

描述（由申请人提供）：铜绿假单胞菌是一种普遍存在的机会性病原体，主要感染患有受损的免疫系统的人，包括移植患者；严重的烧伤患者以及患有囊性纤维化的患者（CF）。在CF的背景下，铜绿假单胞菌建立了一种慢性疾病，其发病率和死亡率是由肺损伤引起的。由于不可思议的抗生素耐药性，感染假单胞菌的CF患者通常患有慢性感染，治疗选择有限。因此，为了提高治疗的疗效，需要检查对可能的治疗靶标的该生物使用的致病机制的基本理解。尽管以前的大多数研究都集中在殖民和感染的初始阶段，但我们提出了一种新方法来寻找治疗方法。越来越多的证据表明，生物膜生长模式很可能与铜绿假单胞菌发病机理有关。铜绿假单胞菌在这种生长条件下产生了许多毒力因子，包括藻酸盐，鼠李糖脂，IV型菌毛和氰化物。其他人，我们发现响应调节剂ALGR控制着所有这些毒力因素。我们发现ALGR是生物膜形成所必需的，并且它抑制了生物膜中的Rhl Quorum传感系统。我们最近创建了一个具有组成性活动的Algrd54e的Algr等位基因。在染色体上携带Algrd54E的PAO1在生物膜形成中有缺陷，不会产生增生酸。我们的数据显示了ALGR的两个新角色：（i）ALGR能够在组成性地“在”上进行组成且; （ii）ALGR控制着铜绿假单胞菌的Rhl Quorum传感系统。拟议的研究具有创新性，因为我们正在研究群体感应在粘液p.a中的作用。拟议的研究也具有创新性，因为我们正在确定转录调节剂的机制，该转录调节剂的机制调节了五个不同的毒力因子，并且当它被磷酸化或未磷酸化或未磷酸化时可以激活转录。要检验的假设是：ALGR控制粘液p.A.中的RHL群体传感系统，从而使生物体能够持续存在于慢性感染中。我们将以两个具体的目的检验这一假设：1）我们将在体外P.A.中确定ALGR控制对RHL QS系统的机制。生物膜形成和2）我们将确定P.A. RHL QS系统对ALGR控制的机制。毒力。 公共卫生相关性：铜绿假单胞菌（P.A.）是一种机会性病原体，主要感染免疫受损的个体，包括移植，严重烧伤和囊性纤维化（CF）患者。感染假单胞菌的CF患者由于这种生物体的天然和选择的抗生素耐药性，通常具有有限的治疗选择。我们最近发表的研究表明，用于控制藻酸盐的调节系统还控制着较大的信号系统（Quorum传感系统），该系统刺激了P.A中的许多毒力决定因素。我们将研究该调节级联反应在大鼠肺部感染模型中的影响。我们预计这项工作的结果将减少P.A.毒力并有助于治疗P.A.慢性感染。