TRPV4 Regulates Mechanosensitive Macrophage Functions in Lung Injury

项目摘要/摘要 压倒性细菌性肺炎损伤并使肺部僵硬，导致急性呼吸窘迫综合征 (ARDS)死亡率高达50%。鉴于许多药物治疗失败，ARDS的管理 是支持性的。ARDS是内皮和肺泡上皮损伤的结果，紧随其后的是募集和 损伤的肺泡炎性细胞积聚。巨噬细胞是肺部的关键效应细胞。 吞噬入侵病原体和分泌细胞因子的损伤过程。我们已经确定， 机械敏感离子通道，瞬时受体电位香草素4(TRPV4)，保护肺免受损伤 通过MAPK新机制建立慢性铜绿假单胞菌肺炎的体内模型 分子开关，从JNK到p38。然而，连接TRPV4和TRPV4的关键细胞内信号分子 MAPK分子开关与促进吞噬/细菌清除的精确细胞表型/功能 以及减少肺损伤的作用尚不清楚。发现新的机械敏感信号机制控制 当肺损伤/僵硬时，巨噬细胞功能将满足设计治疗方法的未得到满足的医学需求 这种毁灭性的疾病。本研究方案研究了TRPV4适应宿主的机制 增强对铜绿假单胞菌肺炎的肺损伤反应。我们研究的长期目标是 为了推断巨噬细胞中依赖TRPV4的细胞内信号，以保护和解决肺炎- 相关的肺损伤。我们的初步数据显示，巨噬细胞的TRPV4信号通过特定的细胞内 在体外改变巨噬细胞激活反应的信号分子。因此，我们提出了这部小说 假设：在铜绿假单胞菌肺炎后，TRPV4调节宿主的反应以保护肺免受损伤 通过巨噬细胞内的信号。这一假设将通过三个相互关联的、但 独立的特异性目标：(1)确定TRPV4增强巨噬细胞的机制 吞噬作用，(2)确定TRPV4限制促炎细胞因子的机制 (3)比较TRPV4在肺泡巨噬细胞和间质巨噬细胞中的作用。 铜绿假单胞菌肺炎小鼠的清除和感染所致的肺损伤。我们的建议是 概念上的创新，因为它是第一个涉及矩阵刚度敏感阳离子通道(TRPV4)和它的 细菌性肺炎及其相关肺组织损伤中的细胞内信号分子。建议数 这项研究对美国国立卫生研究院的任务意义重大，因为我们的目标是探索巨噬细胞中TRPV4如何 整合感染和基质机械信号，以保护肺免受损伤。发现的路径 将确定新的治疗靶点来治疗感染相关的ARDS。

PROJECT SUMMARY/ABSTRACT Overwhelming bacterial pneumonia injures and stiffens the lung leading to acute respiratory distress syndrome (ARDS) that carries a mortality of up to 50%. Given many failed pharmacologic treatments, ARDS management is supportive. ARDS is a consequence of endothelial and alveolar epithelial injury followed by recruitment and accumulation of inflammatory cells in the injured alveolus. Macrophages are the key effector cells in the lung injury process by phagocytizing invading pathogens and secreting cytokines. We have identified that the mechanosensitive ion channel, transient receptor potential vanilloid 4 (TRPV4), protects the lung from injury in an in vivo model of chronic Pseudomonas aeruginosa pneumonia through a novel mechanism of MAPK molecular switching, from JNK to p38. However, the key intracellular signaling molecules that link TRPV4 to the MAPK molecular switch and the precise cell phenotype/function that increases phagocytosis/bacterial clearance and decreases lung injury are unknown. Uncovering novel mechanosensitive signaling mechanisms that control macrophage function when the lung is injured/stiff will fulfill the unmet medical need to design therapies to treat this devastating disease. This research proposal investigates the mechanism whereby TRPV4 adapts the host defense to enhance the lung injury response to P. aeruginosa pneumonia. The long-term goal of our studies is to deduce TRPV4-dependent intracellular signals in macrophages that protect and resolve pneumonia- associated lung injury. Our preliminary data show that macrophage TRPV4 signals through specific intracellular signaling molecules to alter the macrophage activation response in vitro. Therefore, we propose the novel hypothesis: TRPV4 tailors the host response to protect the lung from injury after P. aeruginosa pneumonia through macrophage intracellular signals. This hypothesis will be tested through three interrelated, but independent specific aims: (1) to determine the mechanism whereby TRPV4 enhances macrophage phagocytosis, (2) to determine the mechanism whereby TRPV4 limits pro-inflammatory cytokine production, and (3) to compare the role of TRPV4 in alveolar vs interstitial macrophages in bacterial clearance and infection-induced lung injury after P. aeruginosa pneumonia in mice. Our proposal is innovative in concept as it is the first to implicate a matrix stiffness-sensing cation channel (TRPV4) and its intracellular signaling molecules in bacterial pneumonia and associated lung tissue injury. The proposed research is significant and relevant to the NIH’s mission as we aim to explore how TRPV4 in macrophages integrates the infection and matrix mechanical signaling to protect the lung from injury. The pathways discovered will identify novel therapeutic targets to treat infection-associated ARDS.