Neutrophil-epithelial microRNA shuttling in acute lung injury (ALI)

急性肺损伤 (ALI) 中的中性粒细胞-上皮 microRNA 穿梭

• 批准号: 415286639
• 负责人: Dr. Catharina Conrad
• 金额: --
• 依托单位: Department of Anesthesiology
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/415286639?language=en
• 关键词: Neutrophil; epithelial; microRNA; shuttling; acute

The acute respiratory distress syndrome (ARDS) is a life-threating condition that can develop following major surgery or as a complication of critical illness. ARDS is characterized by acute diffuse lung injury (ALI) with increased pulmonary vascular permeability and loss of aerated lung tissue, clinically resulting in acute hypoxemic respiratory failure and bilateral pulmonary edema. Although mortality rates have been progressively decreased due to advances in supportive care and improved ventilation strategies in the last decade, the outcome of ARDS patients remains unfavorable with mortality rates ranging from 35-60%. Currently, there are no specific pharmacotherapies available.Dysregulated inflammation and alveolar barrier disruption are the central pathophysiological hallmarks of ALI/ARDS. Once recruited into the lung, inflammatory cells come into close spatial contact with the alveolar epithelium and release cytotoxic mediators, resulting in increased vascular permeability and a sustained loss of normal endothelial barrier function. Recently, there is increasing evidence for regulatory roles of microRNAs (miR) in the pathogenesis of ARDS. microRNAs are small non-coding RNAs involved in the post-transcriptional regulation of target genes. The microRNA-223 is considered a negative regulator of inflammation and is upregulated in pulmonary epithelial cells in acute lung injury. In a mouse model of ARDS, miR-223 deficiency resulted in severe lung inflammation, whereas the induction of pulmonary miR-223 overexpression was protective. Interestingly, it has been demonstrated that neutrophil granulocytes transfer miR-223 via exosomes to lung epithelial cells (microRNA shuttling) inducing an anti-inflammatory response that may be targeted for ARDS treatment. Thus, the ultimate goal of this project is to understand the underlying molecular mechanisms of neutrophil-epithelial microRNA shuttling in the pathophysiological phases of ARDS to evaluate the modulation of miR-223 expression as a therapeutic strategy. Consequently, we aim to characterize the kinectics of neutrophil miR-223 release and subsequent uptake in lung epithelia in vitro using co-culture models of human neutrophils and pulmonary epithelial cells. Based on a microarray screening of lung epithelial cells overexpressing miR-223, we intend to identify miR-223-regulated signaling pathways and investigate the functional role of potential miR-223 target genes in attenuating pulmonary epithelial inflammation. Furthermore, we will examine the impact of specific miR-223 deletion in neutrophils in ARDS induction and resolution in vivo using mice with a conditional miR-223 knock-out. In these animals, miR-223 will be reinduced by intratracheal and systemical administration of miR-223 containing nanoparticles during onset and resolution of ARDS. The knowledge of these studies can be utilised to develop a rational strategy for targeted micro-RNA-based therapy of ARDS.

急性呼吸窘迫综合征（ARDS）是一种危及生命的疾病，可在大手术后或作为危重病的并发症发生。ARDS的特征是急性弥漫性肺损伤（ALI），伴有肺血管通透性增加和通气肺组织丧失，临床上导致急性低氧性呼吸衰竭和双侧肺水肿。尽管在过去的十年中，由于支持性护理的进步和通气策略的改善，死亡率已逐渐降低，但ARDS患者的结局仍然不利，死亡率为35- 60%。目前尚无特效的药物治疗，炎症反应失调和肺泡屏障破坏是ALI/ARDS的主要病理生理特征。一旦被招募到肺中，炎性细胞就与肺泡上皮形成紧密的空间接触并释放细胞毒性介质，导致血管通透性增加和正常内皮屏障功能的持续丧失。近年来，越来越多的证据表明microRNA（miR）在ARDS发病机制中的调节作用。microRNA是参与靶基因转录后调节的小型非编码RNA。microRNA-223被认为是炎症的负调节因子，并且在急性肺损伤中在肺上皮细胞中上调。在ARDS小鼠模型中，miR-223缺乏导致严重的肺部炎症，而诱导肺部miR-223过表达具有保护作用。有趣的是，已经证明中性粒细胞通过外来体将miR-223转移到肺上皮细胞（microRNA穿梭），诱导抗炎反应，其可以被靶向用于ARDS治疗。因此，本项目的最终目标是了解ARDS病理生理阶段嗜中性粒细胞-上皮microRNA穿梭的潜在分子机制，以评估miR-223表达的调节作为治疗策略。因此，我们的目标是使用人中性粒细胞和肺上皮细胞的共培养模型来表征中性粒细胞miR-223释放和随后在肺上皮细胞中的体外摄取的动力学。基于对过表达miR-223的肺上皮细胞的微阵列筛选，我们打算鉴定miR-223调节的信号通路，并研究潜在的miR-223靶基因在减轻肺上皮炎症中的功能作用。此外，我们将使用条件性miR-223敲除小鼠，研究中性粒细胞中特定miR-223缺失在体内ARDS诱导和消退中的影响。在这些动物中，在ARDS的发作和消退期间，miR-223将通过动脉内和全身施用含有miR-223的纳米颗粒而被再诱导。这些研究的知识可以用来开发一个合理的策略，有针对性的micro-RNA为基础的治疗ARDS。