Mechanotransduction in Acute Lung Injury

项目摘要 急性肺损伤及其更严重的形式--急性呼吸窘迫综合征 (ARDS)是一种高发病率和高死亡率的破坏性疾病。 对于急性肺损伤的患者，通常使用阳离子进行补充氧气。 加压机械通风，但这可能会导致额外的伤害，称为呼吸机- 诱导肺损伤(VILI)。这项提议的长期目标是改善 对肺过度膨胀(或拉伸)的机制的认识 上皮细胞参与了呼吸机诱导的肺损伤。中心假设是 这种过度扩张通过细胞丢失而导致上皮损伤。 黏附和通过减少细胞迁移而抑制修复机制。 将利用暴露于酸损伤的大鼠来研究VILI的启动机制 或表面活性剂耗尽和微焦点X-直接显示空域力学- 射线成像。将使用体外、体内和体外方法相结合的方法 调查机械拉伸导致细胞粘附性丧失和 通过粘着斑激酶(FAK)信号抑制修复机制。这些 方法包括分离大鼠肺泡II型上皮细胞的原代培养 从机械通气后的大鼠，细胞暴露于机械拉伸 大鼠离体肺的体外和共聚焦显微镜观察。最后，原子力显微镜 将被用来检验机械刚度局部化变化的假设 调节AT2细胞培养过程中的修复机制。拟议的研究将 探讨机械通气过程中导致肺损伤的机制 并为机械转导提供了新的见解，即转换过程 从机械信号到生物信号。

Project Summary Acute lung injury and its more severe form, acute respiratory distress syndrome (ARDS), are devastating illnesses with high rates of incidence and high mortality rates. Patients with acute lung injury are typically provided supplemental oxygen using positive pressure mechanical ventilation, but this can lead to additional injury, termed ventilator- induced lung injury (VILI). The long term objective of this proposal is to improve understanding of the mechanisms by which overdistention (or stretch) of pulmonary epithelial cells contributes to ventilator-induced lung injury. The central hypothesis is that overdistention contributes both to the initiation of epithelial injury through loss of cell adhesion and to inhibition of repair mechanisms through decreased cell migration. Mechanisms of the initiation of VILI will be investigated using rats exposed to acid injury or surfactant depletion and direct visualization of airspace mechanics by microfocal X- ray imaging. A combination of in vitro, in vivo, and ex vivo approaches will be used to investigate the hypothesis that mechanical stretch causes loss of cell adhesion and inhibition of repair mechanisms through focal adhesion kinase (FAK) signaling. These approaches include primary cultures of rat alveolar type II (AT2) epithelial cells isolated from rats following mechanical ventilation, exposure of cells to mechanical stretch in vitro, and confocal microscopy of isolated rat lungs. Finally, atomic force microscopy will be used to test the hypothesis that localized changes in mechanical stiffness regulate the repair mechanisms of AT2 cells in culture. The proposed studies will investigate the mechanisms that contribute to lung injury during mechanical ventilation and provide new insights into mechanotransduction, the process of converting mechanical signals to biological signals.