Ion Flux Regulation of Macrophage Plasticity in Lung Injury and Repair

项目总结/摘要 巨噬细胞（Mφ）对肺的先天性免疫功能至关重要。巨噬细胞的能力 整合来自微生物和组织生态位的信号， 炎性肺损伤项目1显示了细胞外ATP（e[ATP]）激活的基本作用， [Ca2+]嘌呤能受体P2 RX 7（嘌呤能受体2亚型X7）和 钾（K+）通道TWIK 2（双孔结构域弱抑制整流K+通道2），对于 确定巨噬细胞表型。我们发现，典型的P2 RX 7配体e[ATP]支配Mφ 通过控制[Ca 2 +]in和激活TWIK 2 K+外排通道诱导了这种转变 到促炎状态我们还观察到TWIK 2反应本身依赖于 通过e[ATP]激活P2 RX 7并产生Ca 2+内流。因此，项目1，我们将研究 P2 RX 7介导的Ca 2+内流和TWIK 2介导的K+外流之间的关系，我们假设 通过激活决定了向促炎性Mφ（Inf-Mφ）或修复性Mφ（Rep-Mφ）的转变 不同的下游信号通路。将通过解决以下具体问题来检验这一假设 目标。目的1将明确P2 RX 7和TWIK 2激活在介导肺转移中的各自机制， 巨噬细胞极性目的2将明确Mφ离子通道下游的信号通路， 解决炎症性肺损伤。我们通过鉴定P2 RX 7和TWIK 2的激活和信号传导， 负责巨噬细胞表型转换的机制，并通过测试P2 RX 7在 协调TWIK 2在最初的炎症反应中的功能，随后是抗炎反应。 在项目1中的反应，将有可能制定策略，以更有效地解决炎症肺 通过控制巨噬细胞极化增强细菌使肺对损伤产生耐受 杀鼠功能

PROJECT SUMMARY/ABSTRACT Macrophages (Mφ) are essential for the innate immune function of lungs. The ability of macrophages to integrate signals from microbes and the tissue niche and to polarize can either promote or resolve inflammatory lung injury. Project 1 shows a fundamental role of the extracellular ATP (e[ATP]) activated- and [Ca2+]in-sensitive cooperation between the purinergic receptor P2RX7 (Purinergic Receptor 2 subtype X7) and potassium (K+) channel TWIK2 (Two-pore domain Weak Inwardly rectifying K+ channel 2) that is essential for determining the macrophage phenotype. We show that e[ATP], the canonical P2RX7 ligand, governs Mφ polarization through controlling [Ca2+]in and that activation of the TWIK2 K+ efflux channel induces the transition to the pro-inflammatory state. We also observed that the TWIK2 response was itself dependent on the activation of P2RX7 by e[ATP] and resultant Ca2+ influx. Thus, Project 1, we will investigate the interactions between Ca2+ influx mediated by P2RX7 and its tuning of K+ efflux mediated by TWIK2, which we hypothesize determines the transition to either pro-inflammatory Mφ (Inf-Mφ) or reparative Mφ (Rep-Mφ) fate via activation of distinct downstream signaling pathways. This hypothesis will be tested by addressing the following Specific Aims. Aim 1 will define respective mechanisms of P2RX7 and TWIK2 activation in mediating the shift in lung macrophage polarity. Aim 2 will define the signaling pathways downstream of Mφ ion channels that promote and resolve inflammatory lung injury. We posit that by identifying P2RX7 and TWIK2 activation and signaling mechanisms responsible for macrophage phenotype switching, and by testing the role of P2RX7 in coordinating the function of TWIK2 in the initial inflammatory response followed subsequent anti-inflammatory response in Project 1, it will be possible to develop strategies to more effectively resolve inflammatory lung injury and to make lung’s tolerance to injury through controlling macrophage polarization enhancing bacterial killing function of MФ.