SHIP-2 influence on macrophage Fc receptor function

SHIP-2对巨噬细胞Fc受体功能的影响

• 批准号: 6987785
• 负责人: Susheela Tridandapani
• 金额: $ 29.2万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-12-01 至 2009-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6987785
• 关键词: CD antigens; antibody receptor; binding proteins; biological signal transduction; clinical research; confocal scanning microscopy; enzyme activity; genetically modified animals; human subject; immune response; immunoglobulin G; immunoprecipitation; immunoregulation; inflammation; inositol phosphates; laboratory mouse; leukocyte activation /transformation; macrophage; mitogen activated protein kinase; phagocytosis; phosphomonoesterases; phosphorylation; receptor expression; tissue /cell culture; transfection

DESCRIPTION (provided by applicant): Our long-term objective is to understand the regulation of FcgammaR-mediated function of human monocytes/macrophages in health and disease. Clustering of FcgammaR by immune-complexes activates a series of signaling events that culminate in phagocytosis and generation of inflammatory mediators. This activation process is subject to regulation by inhibitory FcgammaR (FcgammaRIIb) and phosphatases such that the final biologic response is tempered. In recent work we found that the inositol phosphatase SHIP-2 is activated upon FcgammaR clustering and serves to downregulate NFkappaB-dependent gene transcription and phagocytosis. Interestingly, although SHIP-1 and SHIP-2 share high-level homology in the catalytic domain, the two enzymes are largely divergent in the non-catalytic regions resulting in unique regulation of signaling pathways. For example, in contrast to the low affinity interaction of SHIP-1 SH2 domain with FcgammaR ITAMs, SHIP-2 associates as efficiently with the phosphorylated ITAM-containing FcgammaR as with the ITIM-containing FcgammaR, suggesting that SHIP-2 influence is likely to have a greater impact on FcgammaR function than that of SHIP-1. Based on these observations we propose the novel hypothesis that SHIP-2 regulates innate immune responses to IgG immune complexes (IC) to contain the inflammatory sequelae that accompany IC clearance, working both through the ITAM-containing and the ITIM-containing FcgammaR, and working in a non-redundant fashion with SHIP-1. To test this hypothesis we propose two Specific Aims. The experiments described in Aim 1 are aimed at analyzing the molecular mechanism of SHIP-2 activation by phagocytic FcgammaR. Such knowledge will be useful in devising ways to subsequently interrupt SHIP-2 activation for functional analyses. In Aim 2, we will perform a detailed assessment of the role of SHIP-2 in modulating FcgammaR-mediated macrophage functions. Our analyses will include a comparison of the ability of SHIP-1 and SHIP-2 to influence FcgammaR signaling and function. We bring to this project several years of experience in dissecting the role of phosphatases in modulating FcgammaR function. Our technical approaches and model systems are innovative and multidisciplinary, encompassing the tools of molecular and cellular biology, biochemistry and immunology. The proposed work holds promise for a better understanding of the IC-mediated inflammatory diseases at the molecular level, and paves the way for novel therapeutic targets.

描述（由申请人提供）：我们的长期目标是了解人类单核细胞/巨噬细胞在健康和疾病中的fcammar介导的功能的调节。免疫复合物对FCGAMMAR聚类激活了一系列信号事件，这些事件最终导致吞噬作用和炎症介质的产生。该激活过程受抑制性FCAMMAR（FCGAMMARIIB）和磷酸酶的调节，以使最终的生物学反应得到缓解。在最近的工作中，我们发现，肌醇磷酸酶Ship-2在FCGAMMAR聚类后被激活，并下调NFKAPPAB依赖性基因转录和吞噬作用。有趣的是，尽管Ship-1和Ship-2在催化结构域中具有高级同源性，但两种酶在非催化区域中在很大程度上存在分歧，从而对信号通路进行了独特的调节。例如，与Ship-1 Sh2结构域与FCGAMMAR ITAM的低亲和力相互作用相比，Ship-2与含磷酸化的ITAM富含ITAM的FCGAMMAR具有有效的效率，与含ITIM的FCGAMMAR一样，这表明Ship-2的影响可能对FCGAMMAR功能产生更大的影响。 基于这些观察结果，我们提出了一种新的假设，即Ship-2调节对IgG免疫复合物（IC）的先天免疫反应（IC）包含伴随IC清除率的炎症后遗症，并通过含ITAM的ITAM和ITIM含ITIM的FCGAMMAR进行工作，并以非固有的方式与Ship-1一起工作。 为了检验这一假设，我们提出了两个具体目标。 AIM 1中描述的实验旨在分析吞噬细胞FCGAMMAR激活Ship-2的分子机制。此类知识将在设计方法中有用，以中断船-2激活以进行功能分析。在AIM 2中，我们将对Ship-2在调节FCGAMMAR介导的巨噬细胞功能中的作用进行详细评估。我们的分析将包括对Ship-1和Ship-2影响FCAMMAR信号传导和功能的能力的比较。 我们为该项目带来了数年的经验，这些经验在剖析磷酸酶在调节FCGAMMAR功能中的作用。我们的技术方法和模型系统是创新和多学科的，涵盖了分子和细胞生物学，生物化学和免疫学的工具。提出的工作有望更好地了解分子水平的IC介导的炎症性疾病，并为新型治疗靶标铺平了道路。