The pel exopolysaccharide gene cluster of Pseudomonas aeruginosa

描述(由申请人提供)：铜绿假单胞菌感染导致囊性纤维化(CF)患者的显著发病率和死亡率。的一项关键功能 这些感染涉及到生物膜群落。另一种是，在慢性感染过程中，铜绿假单胞菌获得了帮助其适应CF环境的突变。这项建议将调查生物膜形成和遗传适应之间的明确联系，即RSCV表型。RSCV通常表现出与非粘液、光滑的菌落形态类型相比，生物被膜形成和抗菌素耐受性增加。RSCV的一个重要特征是提高了生物膜基质胞外多糖PEL的产量。PEL的结构仍不清楚，它的阐明是本提案的目标之一。此外，在慢性囊性纤维化(CF)呼吸道感染过程中，积极选择铜绿假单胞菌RSCV。我们最近发现，RSCV在慢性阻塞性肺疾病中的流行被严重低估，随后我们发现了与RSCV表型相关的新的遗传位点。这些突变产生RSCV的分子机制尚不清楚。最后，我们发现RSCV可以是高度可变的表型，这取决于因果突变。其中一些可变的表型在病原学上是相关的，这表明不同的RSCV在形成生物膜和导致慢性感染的能力上可能不同。这项应用的总体目标是确定PEL的结构，并阐明导致RSCV表型的分子机制，该表型是由RSCV连锁的新突变引起的。我们还将使用慢性动物感染模型和体外细胞免疫分析来检查不同RSCV基因型的致病适应性优势。一旦铜绿假单胞菌出现粘液型遗传变异，患者的预后明显恶化。因此，在粘液转化之前，存在一个关键的免疫或化疗干预的机会窗口。RSCV通常是在粘液样变之前观察到的，因此利用这个机会窗的治疗策略必须考虑到它们。对RSCV和PEL的彻底分析可能会导致治疗药物的开发，并改善CF患者以及其他涉及生物被膜的铜绿假单胞菌感染患者的生活质量。

DESCRIPTION (provided by applicant): Pseudomonas aeruginosa infections result in significant morbidity and mortality in people suffering from cystic fibrosis (CF). A key feature of these infections is that they involve biofilm communities. Another is that during the course of chronic infection, P. aeruginosa acquires mutations that help it adapt to the CF environment. This proposal will investigate a clear link between biofilm formation and genetic adaptation, the RSCV phenotype. RSCVs generally exhibit increased biofilm formation and antimicrobial tolerance relative to the non- mucoid, smooth colony morphotype. One important trait of RSCVs are elevated production of the biofilm matrix exopolysaccharide PEL. The structure of PEL remains unknown, and its elucidation is a goal of this proposal. In addition, P. aeruginosa RSCVs are actively selected for during the course of chronic cystic fibrosis (CF) airway infections. We recently discovered that the prevalence of RSCVs in the CF airways has been grossly underestimated and we subsequently identified novel genetic loci linked to the RSCV phenotype. The molecular mechanism underpinning why these mutations produce RSCVs is unclear. Finally, we found that RSCVs can be highly variable phenotypically, depending upon the causal mutation. Some of these variable phenotypes are pathogenically relevant, suggesting that different RSCVs may vary in their ability to form biofilms and cause chronic infection. The overall goals of this application are to determine the structure of PEL and to elucidate the molecular mechanism leading to the RSCV phenotype that results from novel RSCV- linked mutations. We will also examine the pathogenic fitness advantages of different RSCV genotypes using chronic animal models of infection and in vitro cellular immunological assays. Once mucoid genetic variants of P. aeruginosa emerge, prognosis of CF patients clearly worsens. Thus, there exists a critical window of opportunity for immunological or chemotherapeutic intervention prior to mucoid conversion. RSCVs are usually observed prior to mucoidy, thus therapeutic strategies taking advantage of this window of opportunity would have to account for them. A thorough analysis of RSCVs and Pel may lead to the development of therapeutic agents and improve the quality of life for CF patients as well as individuals with other P. aeruginosa infections that involve biofilms.