Mechanotransduction in Acute Lung Injury

描述（由申请人提供）：急性肺损伤及其更严重的形式，急性呼吸窘迫综合征（ARDS），是具有高发病率和高死亡率的毁灭性疾病。急性肺损伤患者通常使用正压机械通气提供补充氧气，但这可能导致额外的损伤，称为呼吸机诱导的肺损伤（VILI）。本研究的长期目标是提高对肺上皮细胞过度扩张（或伸展）导致呼吸机诱导的肺损伤机制的认识。中心假设是过度扩张通过细胞粘附的丧失和通过减少细胞迁移抑制修复机制来促进上皮损伤的开始。将使用暴露于酸损伤或表面活性剂耗尽的大鼠并通过微焦点X射线成像直接可视化空域力学来研究VILI的启动机制。将使用体外、体内和离体方法的组合来研究机械拉伸导致细胞粘附损失和通过粘着斑激酶（FAK）信号传导抑制修复机制的假设。这些方法包括原代培养大鼠肺泡II型（AT 2）上皮细胞分离大鼠机械通气后，暴露的细胞在体外的机械拉伸，和共聚焦显微镜离体大鼠肺。最后，原子力显微镜将被用来测试的假设，局部的机械刚度的变化调节修复机制的AT 2细胞培养。拟议的研究将调查机械通气期间导致肺损伤的机制，并为机械转导提供新的见解，机械信号转换为生物信号的过程。公共卫生相关性：急性肺损伤是一种毁灭性的疾病，由于在重症监护室的长期停留，会导致重大的生命损失和重大的经济影响。拟议的研究将调查机械通气期间导致肺损伤的机制，并将确定治疗干预的潜在靶点。

DESCRIPTION (provided by applicant): 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 Xray 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. PUBLIC HEALTH RELEVANCE: Acute lung injury is a devastating illness that results in significant loss of life and substantial economic impact due to extended stays in the intensive care unit. The proposed studies will investigate the mechanisms that contribute to lung injury during mechanical ventilation and will identify potential targets for therapeutic intervention.