Regulation of endothelial NADPH oxidase by the cytoskeleton

尽管血管和吞噬NADPH氧化酶之间的差异尚不清楚，但活性氧(ROS)已成为重要的调节分子，它作为关键的第二信使调节信号转导通路，涉及内皮细胞的生长、迁移、黏附和屏障功能。虽然肌动蛋白细胞骨架与中性粒细胞的吞噬和氧化爆发有关，但对于肌动蛋白细胞骨架在内皮NAD[P]H氧化酶组装和激活中的作用却知之甚少。我们的初步研究表明，急性高氧介导的NAD[P]H氧化酶的激活和超氧化物的产生受到皮质肌动蛋白细胞骨架重排、磷酸化的肌球蛋白轻链、小G蛋白和磷脂酸的调节。 我们推测，急性高氧诱导的内皮细胞NAD[P]H氧化酶的激活是通过调节皮质肌动蛋白细胞骨架重构的信号转导通路和通过促进氧化酶亚成分的组装而介导的。在无细胞毒性的情况下，研究急性高氧、肌动蛋白细胞骨架重构与人肺动脉内皮细胞NAD[P]H氧化酶组装和激活的关系。SA#1：将研究NAD[P]H氧化酶激活中肌动蛋白细胞骨架重构的联系途径；SA#2：将表征肌球蛋白轻链磷酸化在NAD[P]H氧化酶激活中的作用；SA#3：将确定皮质素和Cortin在内皮NAD[P]H氧化酶激活中的作用，SA#4：将表征磷脂酶D/ 磷脂酸在内皮NAD[P]H氧化酶激活中的信号转导。了解肌动蛋白细胞骨架重塑在NAD[P]H氧化酶组装和激活中的作用，将有助于开发靶向治疗来调节ROS诱导的信号转导，防止肺损伤和内皮功能障碍。

While differences between vascular and phagocytic NADPH oxidase are yet to be identified, reactive oxygen species (ROS) have emerged as important regulatory molecules which function as critical second messengers modulating signal transduction pathways involved in endothelial cell growth, migration, adhesion and barrier function. While actin cytoskeleton has been implicated in phagocytosis and oxidative burst in neutrophils, very little is known regarding the role of actin cytoskeleton in endothelial NAD[P]H oxidase assembly and activation. Our preliminary studies demonstrate that acute hyperoxia-mediated activation of NAD[P]H oxidase and enhanced production of superoxide is regulated by cortical actin cytoskeleton rearrangement, phosphorylated myosin light chain, small G-proteins and phosphatidic acid. We hypothesize that acute hyperoxia-induced endothelial NAD[P]H oxidase activation is mediated by signal transduction pathways regulating cortical actin cytoskeleton remodeling and by facilitating the assembly of the oxidase sub-components. The following specific aims will investigate the relationship between acute hyperoxia, actin cytoskeletal remodeling and NAD[P]H oxidase assembly and activation in human pulmonary artery endothelial cells in the absence of cytotoxicity. SA#1: Will investigate pathways linking actin cytoskeleton remodeling in NAD[P]H oxidase activation; SA#2: Will characterize the role of myosin light-chain phosphorylation in NAD[P]H oxidase activation; SA#3: Will define the role of cortactin and coronin in endothelial NAD[P]H oxidase activation and SA#4: Will characterize the role of phospholipase D / phosphatidic acid signaling in endothelial NAD[P]H oxidase activation. An understanding of the role of actin cytoskeletal remodeling in NAD[P]H oxidase assembly and activation will allow development of targeted therapies to modulate ROS-induced signaling and prevent lung injury and endothelial dysfunction.