Phagosomal Ion Channels as Therapeutic Targets

 描述（由申请人提供）：单核细胞吞噬细胞通过吞噬吸收和杀死细菌入侵者、清除凋亡细胞、抗原呈递和分泌囊泡之间的组合相互作用来协调先天性免疫应答。 结合信号分子以帮助清除感染。这些功能中的每一个的中心是离子通道和转运蛋白的激活，其驱动细胞内区室中的功能。氯离子通道以及质子转运ATP酶启动吞噬体隔室以进行有效的杀菌活性，并启动分泌囊泡以进行动员和释放。吞噬体内pH、Cl-含量和膜电位的动态变化对最佳杀菌吞噬体腔的发展至关重要。在小的吞噬体内体积的离子含量的变化的驱动力是相对未知的，可能是高度动态的。该提案将探讨吞噬体pH值和存在于吞噬体膜中的离子通道的身份，调节和激活的相互依赖性。离子通道活性和由此产生的吞噬体含量的变化是吞噬体内抗菌环境的主要决定因素，因此，是新的治疗靶点的主要候选者。我们将探索独特的调节信号转导途径，以调节吞噬体中的离子通道运输/表达，从而优化对摄入生物体的杀灭。本申请中提出的实验的目标是优化动态功能谱，用于监测巨噬细胞吞噬体在形成和成熟期间的离子环境的变化，机械地定义有助于该过程的分子组分。这些拟议的研究将解决一价和二价阳离子通量是否可以取代非功能性Cl-通道驱动杀菌活性的问题;如果是这样，如何将适当的通道招募到吞噬体。我们将确定离子运动的时空调节和转运元件，可以微调和维持杀菌环境。总的来说，这些研究将为探索新的机制提供方法和模板，这些机制可能以宿主导向的方式解决多种肺部疾病（包括结核病，慢性肺阻塞性疾病（COPD），囊性纤维化（CF）和哮喘）中的炎症。他们还将提供一个路线图，可能有助于在广泛的细胞生物学背景和疾病状态下研究其他细胞内细胞器。

 DESCRIPTION (provided by applicant): Mononuclear phagocytes orchestrate the innate immune response through the combinatorial interplay between the phagocytic uptake and killing of bacterial invaders, clearance of apoptotic cells, antigen presentation, and secretion of vesicle bound signaling molecules to recruit help in the clearance of infection. Central to each of these functions is the activation of ion channels and transporter proteins that drive function in intracellular compartments. Chloride channels as well as proton translocating ATPases prime the phagosomal compartment for effective bactericidal activity, and secretory vesicles for mobilization and release. Dynamic changes in intraphagosomal pH, Cl- content, and membrane potential are essential to the development of an optimal bactericidal phagosomal lumen. The driving force for changes in ionic content in the small intraphagosomal volume is relatively unknown and likely to be highly dynamic. This proposal will explore the interdependence of phagosomal pH and the identity, regulation, and activation of ion channels present in the phagosomal membrane. Ion channel activity and the resultant changes in phagosomal content are prime determinants of the antimicrobial milieu within the phagosome and, therefore, are prime candidates for new therapeutic targets. We will explore unique regulatory signal transduction pathways to modulate ion channel trafficking/expressing in the phagosome to optimize killing of ingested organisms. The goal of the experiments proposed in this application is the optimization of dynamic functional profiles for monitoring changes in the ionic milieu of th macrophage phagosome during formation and maturation, defining mechanistically the molecular components contributing to the process. These proposed studies will address the question of whether monovalent and divalent cation flux can replace non-functional Cl- channels in driving bactericidal activity; and if so, how the appropriate channels can be recruited to the phagosome. We will determine the spatiotemporal regulation of the ionic movements and the transporter elements which can fine tune and maintain the microbicidal environment. In toto, these studies will provide both methodology and a template for the exploration of novel mechanisms which might resolve inflammation in a host-directed manner in a diversity of pulmonary diseases including tuberculosis, chronic pulmonary obstructive disease (COPD), cystic fibrosis (CF) and asthma. They also will provide a roadmap that could be helpful for the study of other intracellular organelles in a wide range of cell biological contexts and disease states.