Trpm2 Regulation of Phagocyte Bactericidal Activity and Resolution of Lung Injury

项目摘要 肺泡巨噬细胞（AM）的细菌杀伤效率是肺功能的重要决定因素。 解决炎性肺损伤的能力，实际上可能是肺耐受性发展所必需的。 二次感染引起的损伤。然而，细菌杀灭的分子机制尚不清楚 明白支撑项目1的关键观察结果显示， ROS敏感的瞬时受体电位melastatin-2，TRPM 2，一种吞噬体膜相关阳离子 通道，调节M. TRPM 2对控制吞噬体的pH值是必需的 阻断TRPM 2介导的酸化作用可以阻止细菌的杀伤，此外， 炎性肺损伤因此，在项目1中，我们将测试吞噬体相关的核心假设， M β中TRPM 2通过调节吞噬体促进炎性肺损伤的消退 酸化，因此是激活细菌杀灭的中心机制。这一假设将是 通过解决以下具体目标（SA）进行测试。SA #1将决定吞噬体的作用 由氧化酶NOX 2和/或NOX 4诱导的膜TRPM 2活化在调节吞噬体 酸化特性，并因此产生杀有害生物的能力。SA #2将定义关键 TRPM 2调节的巨噬细胞负反馈机制也可能通过抑制吞噬体酸化 NOX 2/NOX 4介导ROS的产生，从而促进M. #3将 确定TRPM 2调节的吞噬体酸化在解决炎性肺损伤中的作用， 在吞噬细胞中特异性缺失TRPM 2的遗传修饰模型， 吞噬体酸化促进对继发感染诱导的损伤的耐受。我们通过 确定负责TRPM 2激活的中央信号机制，它将 有可能制定更有效地解决炎症性肺损伤的策略， 通过增强M.

Project Summary The efficiency of bacterial killing by alveolar macrophages (AMФ) is an essential determinant of the lung's ability to resolve inflammatory lung injury, and indeed may be required for the development of tolerance to lung injury induced by secondary infection. However, the molecular mechanisms of bacterial killing are not well understood. The crucial observation underpinning Project 1 shows a fundamental host-defense function of the ROS-sensitive transient receptor potential melastatin-2, TRPM2, a phagosomal membrane-associated cation channel, in regulating bactericidal activity of MФ. TRPM2 was essential for controlling the pH of phagosomes and blocking of the TRPM2-mediated acidification prevented bacterial killing and, moreover, enhanced inflammatory lung injury. Thus, in Project 1 we will test the central hypothesis that phagosome-associated TRPM2 in MФ promotes the resolution of inflammatory lung injury by regulating phagosomal acidification, and thereby is a central mechanism for activating bacterial killing. This hypothesis will be tested by addressing the following Specific Aims (SA). SA #1 will determine the role of phagosomal membrane TRPM2 activation induced by the oxidases NOX2 and/or NOX4 in regulating the phagosomal acidification property of MФ, and thus in generating bactericidal-competent MФ. SA #2 will define the crucial TRPM2-regulated negative feedback mechanism in MФ that may also acidify phagosomes through dampening NOX2/NOX4-mediated ROS production, and thus the promote bacteria killing function of MФ. SA #3 will determine the role of TRPM2 regulated phagosomal acidification in resolving inflammatory lung injury using genetically modified models with specific deletion of TRPM2 in phagocytic cells, and the role enhanced phagosomal acidification in promoting the tolerance to injury induced by secondary infection. We posit that by identifying the central signaling mechanisms responsible for TRPM2 activation in the MФ phagosomes, it will be possible to develop strategies to more effectively resolve inflammatory lung injury and to make lung's tolerance to injury through enhancing bacterial killing function of MФ.