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 FcgammaR 介导的人类单核细胞/巨噬细胞功能在健康和疾病中的调节。免疫复合物对 FcgammaR 的聚集会激活一系列信号事件，最终导致吞噬作用和炎症介质的产生。该激活过程受到抑制性 FcgammaR (FcgammaRIIb) 和磷酸酶的调节，从而缓和最终的生物反应。在最近的工作中，我们发现肌醇磷酸酶 SHIP-2 在 FcgammaR 聚类时被激活，并用于下调 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度同源性，但这两种酶在非催化区域中存在很大差异，从而导致信号通路的独特调节。例如，与 SHIP-1 SH2 结构域与 FcgammaR ITAM 的低亲和力相互作用相反，SHIP-2 与磷酸化的含 ITAM 的 FcgammaR 的结合与与含 ITIM 的 FcgammaR 的结合一样有效，这表明 SHIP-2 的影响可能是对FcgammaR功能的影响比SHIP-1更大。 基于这些观察，我们提出了新的假设，即 SHIP-2 调节对 IgG 免疫复合物 (IC) 的先天免疫反应，以抑制伴随 IC 清除的炎症后遗症，通过包含 ITAM 和包含 ITIM 的 FcgammaR 发挥作用，并发挥作用以非冗余方式与 SHIP-1 一起使用。 为了检验这一假设，我们提出了两个具体目标。目标 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。这些知识将有助于设计随后中断 SHIP-2 激活以进行功能分析的方法。在目标 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。我们的分析将包括比较 SHIP-1 和 SHIP-2 影响 FcgammaR 信号传导和功能的能力。 我们为这个项目带来了多年剖析磷酸酶在调节 FcgammaR 功能中的作用的经验。我们的技术方法和模型系统具有创新性和多学科性，涵盖分子和细胞生物学、生物化学和免疫学的工具。这项工作有望在分子水平上更好地了解 IC 介导的炎症性疾病，并为新的治疗靶点铺平道路。