Targeted delivery of novel miRNA-based therapeutics for pneumonia-induced acute lung injury

总结 我们建议开发一种新的基于miRNA的治疗方法来治疗细菌性肺炎的急性肺损伤 模型细菌性肺炎是儿童和老年人严重和致命感染的主要原因 国际吧即使有抗生素干预，许多患者仍然迅速进展为急性呼吸窘迫 需要住院、重症监护和机械通气的急性呼吸窘迫综合征（ARDS）。ARDS死亡率 患者的死亡率很高，许多幸存者仍然面临着从各种长期并发症中恢复的漫长道路。 肺功能障碍ARDS的恢复主要依赖于受损气道上皮的再生 细胞，并且不能修复上皮损伤损害肺功能，并使气道容易复发 感染和气道炎症。目前还没有FDA批准的刺激再生的疗法。 肺组织修复肺损伤，这将为肺炎/ARDS患者提供极大的益处。在我们 使用肺炎链球菌（Sp）引起的肺炎小鼠模型的初步研究，我们 观察到急性肺损伤，气道上皮细胞（AEC）大量破坏， 至实质的远端气道，类似于患有ARDS的人类患者中描述的病理学。我们 发现SP感染诱导肺表达一个特定的miRNA家族， 在胚胎发生过程中呼吸上皮细胞的生成中起关键作用。为了测试这种miRNA在 为了修复肺损伤，我们用脂质体治疗了SP感染的小鼠，脂质体中装载了"miRNA模拟物"， 拟在体内模拟和增强内源性miRNA功能的单链RNA分子。我们发现 对SP感染小鼠施用miRNA模拟物促进气道上皮再生，导致 改善肺功能，增强宿主恢复和存活。将这些发现转化为临床 应用，我们建议进一步改进这种技术，靶向递送miRNA模拟物到炎症 肺，以提高疗效，最大限度地减少脱靶效应，并降低潜在的药物毒性。为此我们将 开发载有miRNA模拟物的肺泡靶向脂质体（ATL），并评估肺蓄积， 与非靶向对应物相比，静脉内施用后的治疗功效。我们还将 评价SP感染小鼠和体外培养小鼠的药代动力学/生物分布/药效学和安全性特征。 人体肺第一期短期信托基金计划的结果，将为日后的研究奠定基础，以发展首个- 治疗肺炎/ARDS的再生医学类药物。

SUMMARY We propose to develop a novel miRNA-based therapeutic to treat acute lung injury in a bacterial pneumonia model. Bacterial pneumonia is a leading cause of serious and lethal infections in children and the elderly worldwide. Even with antibiotic intervention, many patients still rapidly progress to acute respiratory distress syndrome (ARDS) requiring hospitalization, intensive care, and mechanical ventilation. Mortality rate in ARDS patients is high, with many survivors still facing a long road to recovery from various long-term complications of lung dysfunction. Recovery from ARDS is critically dependent on regeneration of the damaged airway epithelial cells, and failure to repair epithelial damage impairs lung function and leaves airways vulnerable to recurrent infection and airway inflammation. There are currently no FDA approved therapies to stimulate regrowth of lung tissue to repair lung injury, which would provide great benefits to pneumonia/ARDS patients. In our preliminary studies using a mouse model of pneumonia caused by Streptococcus pneumoniae (Sp), we observed acute lung injury with substantial destruction of airway epithelial cells (AECs) and extensive damage to the distal airway of the parenchyma, similar to pathology described in human patients with ARDS. We discovered that Sp-infection induces lung expression in the lung of a specific family of miRNA that plays a critical role in the generation of respiratory epithelia during embryogenesis. To test the role of this miRNA in repairing lung injury, we treated Sp-infected mice with liposomes loaded with “miRNA-mimic”, a double- stranded RNA molecule intended to mimic and augment the function of endogenous miRNA in vivo. We found that administration of miRNA-mimic to Sp-infected mice promoted airway epithelial regeneration, resulting in improved lung function, enhanced host recovery and survival. To translate these findings into clinical application, we propose to further improve this technology with targeted delivery of miRNA-mimic to inflamed lungs, to increase efficacy, minimize off-target effects, and reduce potential drug toxicity. To this end, we will develop alveolar-targeted liposomes (ATLs) loaded with miRNA-mimic and assess lung accumulation and therapeutic efficacy after intravenous administration compared to the non-targeted counterparts. We will also evaluate pharmacokinetics/bio-distribution/pharmacodynamics and safety profiles in Sp-infected mice and ex vivo human lung. The results of this phase I STTR project will set the stage for future studies to develop a first- in-class drug of regenerative medicine for treating pneumonia/ARDS.