Mechanics and Deformation Responses of Lung Cells

描述（由申请人提供）：我们计划描述肺泡肺泡细胞对变形应力的反应。 这项工作的动机源于我们对呼吸机引起的肺损伤（Vim）的兴趣。 我们长期努力的目标是药物保护肺免受变形性损伤。 拟议的实验建立在我们在过去的资助期间所做的关键观察的基础上，即：a）在培养物中肺泡上皮细胞的拉伸触发了强有力的脂质运输反应; B）运输反应本质上是囊泡的，随应变率和振幅而变化，是温度和能量依赖的，并且可以被操纵; c）抑制变形诱导的脂质运输（DILT）增加了质膜（PM）应力破坏的风险并降低了随后PM修复的可能性; d）与细胞坏死不同的细胞损伤和重新密封可以在整个活肺中容易地证明和定量。这些观察结果表明，DILT是不可或缺的亚溶解PM紧张局势的维持。 实验沿着3个具体目的：1）测量pH和pCO 2对整个活体大鼠肺中与PM损伤和修复相关的机械通气的单独概率的影响; 2）表征原代大鼠肺泡肺细胞中变形应力对PM完整性和鞘脂的摄取、分选和再循环的影响; 3）测量细胞内和细胞外酸碱平衡对DILT、对牵张相关PM创伤的易感性和对后续创伤修复的可能性的影响。 拟议的研究将扩大我们对允许性高碳酸血症的预期和非预期后果的了解;将建立肺泡上皮表型、变形诱导的鞘脂运输和肺泡肺细胞对PM应激失效的易感性之间的机制关系;并将建议DILT和细胞修复导向的治疗干预的分子靶点。

DESCRIPTION (provided by applicant): We plan to characterize the responses of alveolar pneumocytes to deforming stress. Motivation for this work stems from our interest in ventilator-induced lung injury (VIM). The long-term goal of our effort is the pharmaco-protection of the lung from deformation injury. The proposed experiments build on key observations we have made during the past funding period, namely: a) stretching of alveolar epithelial cells in culture triggers a vigorous lipid trafficking response; b) the trafficking response is vesicular in nature, varies with strain rate and amplitude, is temperature and energy dependent and can be pharmacologically manipulated; c) inhibition of deformation induced lipid trafficking (DILT) increases the risk of plasma membrane (PM) stress failure and lowers the likelihood of subsequent PM repair; d) cell wounding and resealing as distinct from cell necrosis can be readily demonstrated and quantified in whole living lungs. These observations suggest that DILT is integral to the maintenance of sublytic PM tensions. Experiments are organized along 3 specific aims: 1) to measure the effects of pH and pCO2 on the separate probabilities of mechanical ventilation associated PM wounding and repair in whole living rat lungs; 2) to characterize in primary rat alveolar pneumocytes the effects of deforming stress on PM integrity and the uptake, sorting and recycling of sphingolipids; 3) to measure the effects of intra- and extracellular acid-base balance on DILT, on the susceptibility to stretch-related PM wounding and on the probability of subsequent wound repair. The proposed studies will expand our knowledge of intended and unintended consequences of permissive hypercapnia; will establish mechanistic relationships between alveolar epithelial phenotype, deformation induced sphingolipid trafficking and the susceptibility of alveolar pneumocytes to PM stress failure; and will suggest molecular targets for DILT and cell repair directed therapeutic interventions.