P AERUGINOSA PHOSPHOLIPASE C--MOLECULAR PATHOGENESIS

铜绿假单胞菌磷脂酶 C--分子发病机制

• 批准号: 2145659
• 负责人: Michael L. Vasil
• 金额: $ 17.04万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-06-01 至 1998-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2145659
• 关键词: Pseudomonas aeruginosa; betaine compound; cystic fibrosis; cytolysis; enzyme activity; fusion gene; gene mutation; host organism interaction; laboratory mouse; laboratory rabbit; laboratory rat; molecular cloning; molecular pathology; monoclonal antibody; opportunistic infections; osmotic pressure; phosphatidylcholines; phospholipase C; posttranslational modifications; protein structure function; pulmonary surfactants; respiratory infections; site directed mutagenesis; virulence

Pseudomonas aeruginosa is an important opportunistic pathogen both in terms of the morbidity and mortality of infections it causes. Most patients with cystic fibrosis (CF), are colonized at an early age with this organism and most CF patients ultimately succumb to a chronic lung infection from P. aeruginosa. The reason for the extraordinary pathogenicity of P. aeruginosa in these patients, as compared to other Pseudomonads for example, is not clear. It is highly probable that the myriad of virulence determinants P. aeruginosa produces contributes to its pathogenic potential. Unfortunately, the exact contribution of these factors, alone or in combination, to even the simplest kind of P. aeruginosa infection has not yet been elucidated. In the past few years studies using molecular, biochemical and genetic approaches have begun to elucidate the structure-function relationships and mechanisms of regulation of virulence determinants. This research is directed at understanding the role of phospholipase C (PLC) production in the pathogenesis of P. aeruginosa infections. PLC has become recognized in recent years as a critical enzyme in both eukaryotic and prokaryotic biology. In eukaryotic organisms it is a critical second messenger in cellular processes, particularly in the function of specific and nonspecific immune mechanisms. In prokaryotic organisms there has been a resurgence of interest in PLC as a critical virulence determinant, both in gram negative and gram positive infections. P. aeruginosa produces two distinct PLCs that could play a significant role in the pathogenesis of lung, as well a other kinds of infections. One PLC is cytolytic (PLC-H) on human erythrocytes and neutrophils, while the other is not (PLC-N) lytic to these kind of cells. These and other features suggest structure-functions relationships between PLC activity and cytolytic activity that will be investigated in this research project. A more complete understanding of the structure-function relationships of both PLCs will lead to better understanding of their role in the pathogenesis of P. aeruginosa, and could result in therapeutic interventions for P. aeruginosa lung infections that were not previously considered. We also propose that derivatives of the substrate products produced by the action of both PLCs on phosphatidylcholine, the major essential lipid in lung surfactant, significantly contribute to the pathogenesis of P. aeruginosa infections. We hypothesize that some of these derivatives are especially relevant to the survival of this organism in the lungs of CF patients. We will investigate how a class of compounds, known as osmoprotectants including, glycine betaine, are able to induce the synthesis of both PLCs in P. aeruginosa. This compound, derived from the one of substrate products of both PLCs, can provide for the survival of this organism in a high osmotic environment, such as found in the lungs of CF patients or in the urinary tract. We propose that understanding this unusual regulatory process could lead to the discovery of novel agents which might at least temper the pathogenic potential of P. aeruginosa, if not directly affect its ability to persist in the lungs of CF patients, or survive in the high osmotic environment of the urinary tract.

铜绿假单胞菌是重要的机会性病原体 它引起的感染的发病率和死亡率的术语。 最多 囊性纤维化患者（CF）在早期定植 这种有机体和大多数CF患者最终屈服于慢性肺 铜绿假单胞菌感染。 非凡的原因 与其他 例如，假单胞菌尚不清楚。 很有可能 无数的毒力决定因素铜绿假单胞菌产生的有助于 它的致病潜力。 不幸的是，这些的确切贡献 一个单独或结合的因素，甚至是最简单的。 铜绿感染尚未阐明。 在过去的几年中 使用分子，生化和遗传学方法的研究已经开始 阐明结构功能关系和机制 毒力决定因素的调节。 这项研究针对 了解磷脂酶C（PLC）生产在 铜绿假单胞菌感染的发病机理。 PLC已被认可 近年来是真核和原核的关键酶 生物学。 在真核生物中，这是关键的第二使者 蜂窝过程，特别是在特定和 非特异性免疫机制。 在原核生物中有一个 对PLC的兴趣复兴是一种关键的毒力决定因素，两者都 在革兰氏阴性和革兰氏阳性感染中。 铜绿假单胞菌产生 两个不同的PLC可以在发病机理中起重要作用 肺部以及其他种类的感染。 一个PLC是细胞溶解的 （PLC-H）在人类红细胞和中性粒细胞上，而另一个不是 （PLC-N）裂解对这类细胞。 这些和其他功能暗示 PLC活性与细胞溶解之间的结构 - 功能关系 该研究项目将进行调查的活动。 更多 完全了解两者的结构功能关系 PLC将更好地理解其在发病机理中的作用 铜绿假单胞菌，可能会导致P.的治疗干预措施 以前未考虑的铜绿肺感染。 我们也是 提出该动作产生的底物产品的衍生物 磷脂酰胆碱上的两个PLC是肺的主要必需脂质 表面活性剂显着有助于铜绿假单胞菌的发病机理 感染。 我们假设其中一些衍生物尤其是 与该生物在CF患者肺中的生存有关。 我们将研究一类化合物（称为渗透保护剂） 包括甘氨酸甜菜碱能够诱导两个PLC的合成 在铜绿假单胞菌中。 该化合物，源自底物之一 这两个PLC的产品都可以在A中提供该生物的生存 高渗透环境，例如在CF患者的肺中发现或 尿路。 我们建议理解这种异常的监管 过程可能导致发现新颖的代理，至少可能 降低铜绿假单胞菌的致病潜力，如果不直接影响 它具有在CF患者的肺中持续存在的能力，或在 尿路的高渗透环境。