Inducible Renitence in Macrophages

描述（由申请人提供）：巨噬细胞对先天免疫感染至关重要。脂多糖（LPS）和细胞因子如干扰素-？（IFN?）和肿瘤坏死因子- α (TNF -)增加了它们的杀微生物活性，但也增加了因炎症引起的组织损伤。由于针对慢性炎症的治疗使患者容易受到感染，因此需要新的策略来选择性地增加巨噬细胞的抗菌活性。本研究的长期目标是通过对巨噬细胞基础生物学的研究来设计这样的策略。该实验室最近发现，将小鼠巨噬细胞暴露于细菌、LPS、IFN？或TNF -导致溶酶体稳定以抵抗机械损伤，这种现象被称为“诱导性忍耐”或IR。由于空泡膜损伤对许多致病微生物的毒力、病毒感染和微关节炎症至关重要，因此这种新现象可能被用于治疗。本工作的目的是确定诱导记忆的细胞和分子基础。核心假设是，记忆是由经典激活诱导的，由膜损伤修复增强机制组成。这些研究的实验模型是一个巨噬细胞溶酶体或吞噬溶酶体受到控制水平的物理扰动的系统，这使得可以定量评估抵抗或修复损伤的机制。中心假设将通过解决三个具体目标来验证。第一个目标是确定诱导人类和小鼠巨噬细胞的条件和因素。将在经典活化的巨噬细胞、选择性活化（伤口愈合）的巨噬细胞和调节性巨噬细胞以及用其他药物治疗的巨噬细胞中测量renrenence。第二个目标将确定膜损伤修复机制在记忆中的作用。我们将测量吞噬溶酶体损伤和修复的动力学，并分析空泡钙、synaptotagmin VII和酸性鞘磷脂酶对修复的贡献。第三个目标是确定耐药在巨噬细胞抵抗革兰氏阳性单核增生李斯特菌感染中的作用，这种细菌通常通过破坏液泡膜逃逸到细胞质中。通过定义IR的细胞和分子基础，本研究将引入巨噬细胞功能操纵的新策略。选择性地增加耐受性的疗法可以减少由微颗粒引起的炎症，或使免疫抑制的患者和患有慢性炎症性疾病（如动脉硬化和克罗恩病）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.