Modulation of neutrophil function through emperipolesis

项目摘要 近50年来，人们已经知道中性粒细胞经常出现在巨核细胞(MK)中，这是一种 组织学现象称为瘀斑。使用我们开发的新工具在体外研究这一过程 在活体内，我们发现癫痫是常见的，并随着实验性炎症应激的增加而增加 一种小鼠系统。中性粒细胞穿透MK细胞质，捐献其表面的一小部分 从膜到血小板，然后才能存活和完整地出现。我们的初步数据显示，中性粒细胞 在胚胎期上调MK来源的外切体，并随着迁移能力的增强而出现。在基础上建设 这些结果，我们探索了一种假说，即胚乳是一种新的细胞间相互作用，调节 中性粒细胞的功能。 我们在两个独立但互补的目标上检验这一假设。在目标I中，我们考察了 对中性粒细胞效应器功能、代谢和体内的影响，尤其是MK外切体 中性粒细胞依赖的K/BxN血清转移性关节炎中的迁移。在AIM II中，我们采用了全安装3D 骨髓成像、双光子活体显微镜、特异性MK缺失和潜在的血栓形成 封锁以测试黄褐斑代表一条数量上重要的途径的可能性 体内中性粒细胞从骨髓中排出，包括实验性关节炎。 总之，这些研究将定义一种新的MK和中性粒细胞之间的合作形式，这种合作形式可以调节 中性粒细胞参与健康和疾病的能力。更广泛地说，基于我们最近的 确定巨噬细胞是关节炎中IL-1的来源，这些研究继续发展对 MKS和中性粒细胞作为全身炎症性疾病的参与者。这些“高风险、高回报” 对以前被忽视的生物过程的研究，在哺乳动物物种中被广泛保守，将 作为一种新的细胞中细胞现象的扩展研究的阶段。

Project Summary For almost 50 years it has been known that neutrophils regularly appear within megakaryocytes (MKs), a histological phenomenon termed emperipolesis. Using new tools we developed to study this process in vitro and in vivo, we found that emperipolesis is common and increases with experimental inflammatory stress in a murine system. Neutrophils penetrate into the MK cytoplasm, donating a fraction of their surface membrane to platelets before emerging viable and intact. Our preliminary data show that neutrophils take up MK-derived exosomes during emperipolesis and emerge with enhanced migratory capacity. Building on these results, we explore the hypothesis that emperipolesis is a novel cell-in-cell interaction that modulates the function of neutrophils. We test this hypothesis in two independent but complementary aims. In Aim I, we examine the effect of emperipolesis, and in particular of MK exosomes, on neutrophil effector functions, metabolism, and in vivo migration in neutrophil-dependent K/BxN serum transfer arthritis. In Aim II, we employ whole-mount 3D marrow imaging, 2-photon in vivo microscopy, and specific MK deletion and potentially emperipolesis blockade to test the possibility that emperipolesis represents a quantitatively important pathway of neutrophil egress from bone marrow in vivo, including in experimental arthritis. Together, these studies will define a new form of cooperation between MKs and neutrophils that modulates the ability of neutrophils to participate in health and disease. More generally, building upon our recent identification of MKs as a source of IL-1 in arthritis, these studies continue to develop the understanding of MKs and neutrophils as participants in systemic inflammatory disease. These “high risk, high reward” studies of a previously overlooked biological process, widely conserved across mammalian species, will set the stage for an extended investigation of emperipolesis as a novel cell-in-cell phenomenon.