Inducible Renitence in Macrophages

描述（由申请人提供）：巨噬细胞对感染的先天免疫至关重要。激活巨噬细胞的脂多糖（LPS）和细胞因子，如干扰素？(IFN?)肿瘤坏死因子-β（TNF-α）增加了它们的杀微生物活性，但也增加了炎症对组织的损伤。由于针对慢性炎症的治疗使患者易受感染，因此需要可以选择性增加巨噬细胞抗菌活性的新策略。这项研究的长期目标是通过研究基本的巨噬细胞生物学来设计这样的策略。这个实验室最近发现，暴露于细菌，LPS，IFN？由于空泡膜损伤对于许多病原微生物的毒力、病毒感染和微关节炎症是必不可少的，这种新的现象可能在治疗上被利用。本工作的目的是确定诱导renitence的细胞和分子基础。中心假设是，renitence是由经典的激活和膜损伤修复的增强机制组成。这些研究的实验模型是一个系统，其中巨噬细胞溶酶体或吞噬溶酶体受到控制水平的物理扰动，这使得定量评价机制，抵抗或修复损伤。中心假设将通过解决三个具体目标进行检验。第一个目标是确定诱导人和小鼠巨噬细胞再生的条件和因素。将在经典活化的巨噬细胞、交替活化的（伤口愈合）巨噬细胞和调节性巨噬细胞以及用其他药剂处理的巨噬细胞中测量再生。第二个目标将确定膜损伤修复机制在renitence中的作用。将测量吞噬溶酶体损伤和修复的动力学，并分析空泡钙、突触结合蛋白VII和酸性鞘磷脂酶对复性的贡献。第三个目标将确定renitence在巨噬细胞抵抗革兰氏阳性细胞内病原体单核细胞增生李斯特菌感染中的作用，该病原体通常通过破坏空泡膜进入细胞质。通过定义IR的细胞和分子基础，本研究将为巨噬细胞功能的操纵引入一种新的策略。选择性地增加肾功能的疗法可以减少由于微粒引起的炎症，或者使免疫抑制患者和患有慢性炎性疾病（如克罗恩病和克罗恩病）的个体受益。

DESCRIPTION (provided by applicant): Macrophages are essential to innate immunity to infections. Activation of macrophages by lipopolysaccharide (LPS) and cytokines such as interferon-? (IFN?) and tumor necrosis factor-� (TNF�) increases their microbicidal activities but also increases damage to tissues due to inflammation. As therapies which target chronic inflammation leave patients vulnerable to infections, new strategies are needed that can selectively increase macrophage antimicrobial activities. The long-term goal of this research is to devise such strategies through investigations of fundamental macrophage cell biology. This lab discovered recently that exposure of murine macrophages to bacteria, LPS, IFN? or TNF� leads to stabilization of their lysosomes against mechanical damage, a phenomenon termed "inducible renitence" or IR. As vacuolar membrane damage is essential to the virulence of many pathogenic microbes, to infection by viruses and to inflammation by micro-articulates, this novel phenomenon could potentially be exploited therapeutically. The objective of the present work is to define the cellular and molecular basis of inducible renitence. The central hypothesis is that renitence is induced by classical activation and consists of enhanced mechanisms of membrane damage-repair. The experimental model for these studies is a system in which macrophage lysosomes or phagolysosomes are subjected to controlled levels of physical perturbation, which allows quantitative evaluation of mechanisms that resist or repair damage. The central hypothesis will be tested by addressing three specific aims. The first aim will determine the conditions and factors which induce renitence in human and murine macrophages. Renitence will be measured in classically activated macrophages, alternatively activated (wound-healing) macrophages and regulatory macrophages, as well as macrophages treated with other agents. The second aim will determine the role of membrane damage-repair mechanisms in renitence. The kinetics of phagolysosome damage and repair will be measured and the contributions of vacuolar calcium, synaptotagmin VII and acid sphingomyelinase to renitence will be analyzed. The third aim will determine the role of renitence in macrophage resistance to infection by the Gram-positive intracellular pathogen Listeria monocytogenes, which normally scapes into cytoplasm by damaging vacuolar membranes. By defining the cellular and molecular basis of IR, this research will introduce a new strategy for manipulation of macrophage function. Therapies which increase renitence selectively could reduce inflammation due to micro-particulates or benefit immunosuppressed patients and individuals with chronic inflammatory diseases, such as therosclerosis and Crohn's disease.