Nanoparticle Drug Delivery in Post-Pneumonectomy Compensatory Lung Growth

描述（由申请人提供）：成年犬的肺切除术（PNX）模拟了限制性肺病的后果，是代偿性肺生长（CLG）的稳健模型，其特征是早期肺泡细胞增殖肥大、进行性间隔重塑、腺泡结构逐渐正常化以及肺功能在数月内逐渐恢复。 PNX 后机械信号激活几乎所有主要的稳态通路；下游反应对药物刺激非常敏感，但外源性增强的肺泡组织生长并未通过功能增强得到反映。这种结构-功能差距是该领域转化进展的主要障碍。造成差距的潜在原因包括：a) 间隔成分的不均匀和/或过度刺激，b) 缺乏按比例增强的间隔重塑来优化气体交换、屏障并最大限度地减少结构变形，以及 c) 需要生长促进剂的肺特异性可滴定递送。我们的目标是制定平衡增强肺泡生长/重塑的策略，旨在最大限度地减少变形并增加功能获益的可能性。我们的假设是，持续低剂量吸入纳米颗粒 (NP) 输送补充性生长促进剂，以平衡刺激肺泡生长/重塑，增强 PNX 后的肺结构和功能。将合成生物相容性生物可降解聚（乳酸-乙醇酸）或 PLGA 封装的纳米粒子，每个纳米粒子都含有已知的生长促进剂：全反式视黄酸（RA）、角质形成细胞生长因子（KGF）及其受体（KGFR）的肽或 cDNA、或促红细胞生成素（EPO）及其受体（EPOR），组合施用以按比例刺激肺泡上皮、间质和内皮细胞，促进/保护有益的隔膜重塑，并保留/恢复正常结构。磁性标签和荧光标记最初可以作为示踪剂掺入纳米颗粒中，但在最终的治疗配方中被省略。目标 1：表征含有单独和组合生长促进剂的 NP 在人肺细胞中的体外剂量反应、作用持续时间和生物安全性。优化 NP 配方以实现持续释放和适度作用。目标 2：确定含有生长促进剂组合的 NP 的体内生物学作用。将悬浮液中的纳米粒子雾化到成年大鼠和试验犬体内，以表征长期给药的生物分布和生物安全性。 目标 3：确定 NP 鸡尾酒对 PNX 后 CLG 和成年犬功能的长期影响。将使用非侵入性成像（HRCT 和 UTE MRI）、生理测试（休息和运动）以及详细的结构分析来监测治疗反应。这种新颖的肺再生多途径范例与癌症化疗中使用的方法相似，结合了最先进的纳米技术、成像和生理技术，并建立了跨学科合作。研究结果将影响肺部再生修复的基本概念，弥合肺部生长调控的关键知识差距，并可立即转化为临床应用。

DESCRIPTION (provided by applicant): Pneumonectomy (PNX) in adult canines mimics the consequences of restrictive lung disease and is a robust model of compensatory lung growth (CLG), characterized by early alveolar cellular proliferation-hypertrophy, progressive septal remodeling, gradual normalization of acinar architecture and incremental restoration of lung function over many months. Post-PNX mechanical signals activate nearly all the major homeostatic pathways; downstream responses are very sensitive to pharmacological stimulation but exogenously enhanced alveolar tissue growth has not been mirrored by functional enhancement. This structure-function gap represents a key obstacle to translational progress in the field. Potential reasons for the gap include: a) uneven and/or over- stimulation of septal components, b) lack of proportionally enhanced septal remodeling to optimize the gas exchange, barrier and minimize architecture distortion, and c) need for lung-specific titratable delivery of growth promoters. Our goal is to develop a strategy of balanced enhancement of alveolar growth/remodeling aimed at minimizing distortion and increasing the likelihood of functional benefit. Our hypothesis is that sustained low-dose inhalational nanoparticle (NP) delivery of complementary growth-promoting agents selected for balanced stimulation of alveolar growth/remodeling enhances post-PNX lung structure and function. Biocompatible biodegradable poly(lactic-co-glycolic acid) or PLGA-encapsulated NPs will be synthesized each containing a known growth promoter: all-trans retinoic acid (RA), peptide or cDNA of keratinocyte growth factor (KGF) and its receptor (KGFR), or erythropoietin (EPO) and its receptor (EPOR), to be administered in combination to proportionally stimulate the alveolar epithelium, interstitium and endothelium, promote/protect beneficial septal remodeling, and preserve/restore normal architecture. Magnetic tag and fluorescent labels may be incorporated into NPs as tracers initially, but omitted in final therapeutic formulations. Aim 1: Characterize i vitro dose-response, duration of action, and biosafety of NPs containing individual and combination growth promoting agent in human lung cells. Optimize NP formulations for sustained release and modest action. Aim 2: Determine in vivo biological action of NPs containing combinations of growth promoting agents. NPs in suspension will be nebulized into adult rats and pilot dogs to characterize bio-distribution and biosafety of chronic administration. Aim 3: Determine the long-term effects of NP cocktails on post-PNX CLG and function in adult canines. Therapeutic response will be monitored using non-invasive imaging (HRCT and UTE MRI), physiological testing (rest and exercise), and detailed structural analysis. This novel multi pathway paradigm for lung regeneration parallels the approach used in cancer chemotherapy, combines state-of-the-art nanotechnology, imaging and physiological techniques, and forges inter-disciplinary collaborations. Results will impact fundamental concepts of lung regeneration-repair, bridge a key knowledge gap in the manipulation of lung growth, and are immediately translatable to the bedside.