Control of lung permeability by oxidized phospholipids

描述(申请人提供)：氧化磷脂与其他生物活性物质一起出现在肺循环中，在病理条件下，如急性肺损伤、脓毒症、肺部炎症和呼吸机诱导的肺损伤。在这些情况下，肺血管屏障功能在很大程度上受到损害，但EC功能障碍的严重程度取决于肺循环中存在的屏障干扰剂和屏障保护剂之间的平衡。氧化天然磷脂成分1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine(OxPAPC)可复制氧化磷脂所产生的广泛的生理效应。虽然OxPAPC在屏障保护中的确切作用尚未得到评价，但我们的初步研究强烈建议OxPAPC对人肺内皮细胞具有屏障保护作用，并将其与肌动蛋白细胞骨架重塑、通过黏附连接(AJ)增强细胞间相互作用以及局灶性粘连(FA)的外周重塑联系起来。我们推测OxPAPC的生物活性成分可能通过触发由小GTP酶Rac和CDC42及其下游的细胞骨架、FA和AJ蛋白靶标介导的细胞内信号通路来促进损伤肺血管屏障的完整性。具体目标#1将利用细胞培养和动物模型确定参与肺屏障保护的氧化磷脂的特定成分，并探索RAC/CDC42依赖的EC细胞骨架组织和屏障保护的调节。具体目标#2将确定参与RAC/Cdc42介导的与EC屏障促进相关的FA重塑的FA蛋白靶点。具体目标#3：将研究RAC和Cdc42依赖的机制在OxPAPC介导的AJ增强中的作用，并研究FA和AJ蛋白复合体在OxPAPC介导的屏障保护中的相互作用。我们相信，这项研究的结果将显著影响我们对氧化磷脂在RAC介导的EC屏障调节中的作用的理解，并使我们能够对氧化磷脂在危及生命的条件下(如急性肺损伤和炎症)肺屏障保护的代偿机制中的作用产生新的见解。

DESCRIPTION (provided by applicant): Oxidized phospholipids appear among other bioactive substances in lung circulation under pathological conditions such as acute lung injury, sepsis, lung inflammation, and ventilator-induced lung injury. Lung vascular barrier function under these conditions is largely compromised, but severity of EC dysfunction is determined by a balance between barrier-disruptive and barrier-protective agents present in pulmonary circulation. Oxidation of a natural phospholipid component, 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (OxPAPC) reproduces a wide spectrum of physiological effects exerted by oxidized phospholipids. Although precise role of OxPAPC in barrier protection has not been yet evaluated, our preliminary studies strongly suggest barrier protective effects of OxPAPC on human pulmonary EC and link them to the actin cytoskeletal remodeling, enhanced intercellular interaction via adherens junctions (AJ), and peripheral remodeling of focal adhesions (FA). We hypothesize that bioactive components of OxPAPC may contribute to the vascular barrier integrity in the injured lung by triggering intracellular signaling pathways mediated by small GTPases Rac and Cdc42 and their downstream cytoskeletal, FA and AJ protein targets. Specific Aim #1 will determine specific components of oxidized phospholipids involved in the lung barrier protection using cell culture and animal models, and explore Rac/Cdc42-dependent regulation of EC cytoskeletal organization and barrier protection. Specific Aim #2 will determine FA protein targets involved in Rac/Cdc42-mediated FA remodeling related to EC barrier promotion. Specific Aim #3: will study involvement of Rac- and Cdc42-dependent mechanisms in the OxPAPC-mediated AJ enhancement and investigate an interaction of FA and AJ protein complexes in OxPAPC-mediated barrier protection. We believe that the results obtained in this study will significantly impact our understanding of the role of oxidized phospholipids in the EC barrier regulation mediated via Rac and Cdc42-specific mechanisms (SA#1) involving remodeling of focal adhesions (SA#2) and adherens junctions (SA#3), and allow us to develop new insights into the role of oxidized phospholipids in the compensatory mechanisms of the lung barrier protection under life-threatening conditions, such as acute lung injury and inflammation.