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。的一个关键特征 这些感染涉及生物膜群落。另一个原因是，在慢性感染过程中，铜绿假单胞菌获得了有助于其适应CF环境的突变。该提案将调查生物膜形成和遗传适应之间的明确联系，RSCV表型。相对于非粘液样光滑菌落形态型，RSCV通常表现出增加的生物膜形成和抗微生物耐受性。RSCV的一个重要特征是生物膜基质胞外多糖PEL的产生增加。PEL的结构仍然未知，其阐明是本提案的目标。此外，铜绿假单胞菌RSCV在慢性囊性纤维化（CF）气道感染过程中被积极选择。我们最近发现，CF气道中RSCV的患病率被严重低估，我们随后确定了与RSCV表型相关的新遗传基因座。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。这些可变表型中的一些是致病相关的，这表明不同的RSCV可能在它们形成生物膜和引起慢性感染的能力方面有所不同。本申请的总体目标是确定PEL的结构并阐明导致由新型RSCV连锁突变引起的RSCV表型的分子机制。我们还将使用慢性感染动物模型和体外细胞免疫学测定来研究不同RSCV基因型的致病适应性优势。一旦铜绿假单胞菌的粘液样遗传变体出现，CF患者的预后明显恶化。因此，在粘液转化之前存在免疫或化疗干预的关键机会窗口。RSCV通常在粘液性之前观察到，因此利用该机会窗口的治疗策略必须考虑它们。对RSCV和Pel的全面分析可能会导致治疗剂的开发，并改善CF患者以及涉及生物膜的其他铜绿假单胞菌感染个体的生活质量。

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.