Targeting Myeloid Dependent MicroRNAs in Acute Respiratory Distress Syndrome

摘要 肺部炎症是导致急性呼吸窘迫综合征（ARDS）的重要因素之一。的 对感染或组织损伤作出反应的初始急性肺部炎症导致白细胞的深度浸润 和炎症细胞因子的释放。骨髓细胞，包括巨噬细胞，是介导 急性肺部炎症的发作和消退。然而，重新编程巨噬细胞的触发器， 控制过度炎症仍然不完全了解。最近的工作表明， microRNAs（miRNAs）在炎症性疾病中的作用然而，很少有研究来评估 巨噬细胞中的miRNAs在控制肺部炎症中的功能作用。我们假设 肺部炎症的控制涉及巨噬细胞中特异性miRNA的转录诱导。我们 一项研究发现，在巨噬细胞募集过程中，microRNA-147（miR-147）显著增加。 肺部炎症miR-147的诱导依赖于缺氧诱导因子1A。在功能上，miR- miR-147在体外控制巨噬细胞炎症，骨髓来源的miR-147抑制肺 体内炎症。我们鉴定并证实了线粒体复合体相关蛋白 NDUFA 4是miR-147的主要靶点。新的和令人兴奋的初步数据表明， NDUFA 4，miR-147抑制炎症细胞因子如IL-6，IL-1β和TNFα的产生， 巨噬细胞其他证据支持抑制琥珀酸氧化和伴随的 组蛋白超甲基化有助于miR-147/NDUFA 4介导的效应。最后，过度表达 miR-147改善了体内肺部炎症的恢复。在这里，我们测试的假设，miR- 147/NDUFA 4轴代表巨噬细胞中控制肺部炎症的内源性保护途径。 为了检验这一假设，提出了以下三个目标。在目标1中，我们将使用最先进的miR- 147只报告小鼠研究miR-147的转录调控，并研究miR-147是如何在小鼠体内表达的。 147/NDUFA 4轴在体外控制巨噬细胞炎症。在目标2中，我们将执行原理证明 在人类ARDS中的研究，并采用最先进的转基因小鼠来研究 体内肺部炎症期间巨噬细胞中的miR-147/NDUFA 4轴。在目标3中，我们将进一步探讨 miR-147/NDUFA 4轴在调节肺部炎症中的治疗靶向。的完成 这项研究将确定miRNA靶点作为ARDS的创新治疗方法。

Abstract Lung inflammation is one of the profound contributors to acute respiratory distress syndrome (ARDS). The initial acute lung inflammation in response to infection or tissue injury leads to profound infiltration of leukocytes and the release of inflammatory cytokines. Myeloid cells, including macrophages, are key players mediating the onset and resolution of acute lung inflammation. However, the triggers that reprogram macrophages to control excessive inflammation remain incompletely understood. Recent work has demonstrated a key role for microRNAs (miRNAs) in inflammatory diseases. However, little research has been done to assess the functional role of miRNAs in macrophages in the context of controlling lung inflammation. We hypothesize that control of lung inflammation involves the transcriptional induction of specific miRNAs in macrophages. Our study has identified microRNA-147 (miR-147) to be dramatically increased in recruited macrophages during lung inflammation. The induction of miR-147 is dependent on hypoxia-inducible factor 1A. Functionally, miR- 147 controls macrophage inflammation in vitro, and myeloid-derived miR-147 dampens lung inflammation in vivo. We identified and confirmed the mitochondria complex associated protein NDUFA4 as a leading miR-147 target. New and exciting preliminary data indicated that by targeting NDUFA4, miR-147 dampens the production of inflammatory cytokines such as IL-6, IL-1β, and TNFα in macrophages. Additional evidence supports that inhibition of succinate oxidation and concomitant histone hypermethylation contributes to the miR-147/NDUFA4 mediated effect. Finally, overexpression of miR-147 improves the recovery from lung inflammation in vivo. Here, we test the hypothesis that the miR- 147/NDUFA4 axis represents an endogenous protective pathway in macrophages to control lung inflammation. The following three aims have been proposed to test this hypothesis. In Aim 1, we will use state-of-art miR- 147 reporter mice to study the transcriptional regulation of miR-147 and investigate how miR- 147/NDUFA4 axis controls macrophage inflammation in vitro. In Aim 2, we will perform proof-of-principle studies in human ARDS and employ cutting-edge transgenic mice to investigate the functional role of miR-147/NDUFA4 axis in macrophages during lung inflammation in vivo. In Aim 3, we will further explore the therapeutic targeting of miR-147/NDUFA4 axis in modulating lung inflammation. The completion of the proposed study will identify miRNA targets as an innovative therapeutic approach for ARDS.