Mechanics and Deformation Responses of Lung Cells

描述(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诱导的肺损伤(VIM)的兴趣。我们努力的长期目标是用药物保护肺免受变形损伤。拟议的实验以我们在上一个资助期所做的主要观察为基础，即：a)培养中的肺泡上皮细胞拉伸触发强烈的脂质转运反应；b)转运反应本质上是泡状的，随应变速率和幅度的变化而变化，依赖于温度和能量，并且可以通过药物进行操纵；c)抑制变形诱导的脂质转运(DILT)增加了质膜(PM)应激失败的风险，并降低了随后PM修复的可能性；d)细胞损伤和重新封闭与细胞坏死不同，可以很容易地在整个活肺中显示和量化。这些观察表明，DILT对于维持亚溶血性PM的紧张状态是不可或缺的。 实验按3个特定目标组织：1)测量pH和PCO2对整个活体大鼠肺机械通气相关PM损伤和修复的单独概率的影响；2)在原代大鼠肺泡细胞中表征变形应激对PM完整性和神经鞘脂脂摄取、分类和循环的影响；3)测量细胞内和细胞外酸碱平衡对DILT、拉伸相关PM损伤的敏感性和后续伤口修复概率的影响。 拟议的研究将扩大我们对允许性高碳酸血症预期和意外后果的认识；将建立肺泡上皮表型、变形诱导的鞘脂运输和肺泡肺泡上皮细胞对PM应激失败的易感性之间的机制关系；并将为DILT和细胞修复定向治疗干预提供分子靶点。

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.