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补充氧气，但这可能导致额外的损伤，称为呼吸机诱导肺损伤（VILI）。本建议的长期目标是提高对肺上皮细胞过度膨胀（或拉伸）导致呼吸机诱导的肺损伤的机制的理解。中心假设是，过度膨胀既通过细胞粘附丧失导致上皮损伤，又通过减少细胞迁移抑制修复机制。研究人员将利用暴露于酸损伤或表面活性剂耗竭的大鼠和通过微焦x射线成像直接可视化的空域力学来研究VILI的发生机制。结合体外、体内和离体方法，将研究机械拉伸导致细胞粘附丧失和通过局灶粘附激酶（FAK）信号通路抑制修复机制的假设。这些方法包括对机械通气后分离的大鼠肺泡II型（AT2）上皮细胞进行原代培养，对细胞进行体外机械拉伸，以及对分离的大鼠肺进行共聚焦显微镜观察。最后，原子力显微镜将用于验证机械刚度的局部变化调节培养AT2细胞修复机制的假设。这些研究将探讨机械通气过程中导致肺损伤的机制，并为机械信号转化为生物信号的过程提供新的见解。公共卫生相关性：急性肺损伤是一种毁灭性疾病，由于在重症监护病房的长期停留，会造成重大的生命损失和重大的经济影响。拟议的研究将探讨机械通气期间肺损伤的机制，并确定治疗干预的潜在目标。

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.