Modulation of neutrophil function through emperipolesis

项目概要 近 50 年来，人们都知道中性粒细胞经常出现在巨核细胞 (MK) 中，巨核细胞是一种 称为伸入现象的组织学现象。使用我们开发的新工具在体外研究这个过程 在体内，我们发现伸入现象很常见，并且随着实验性炎症应激而增加 小鼠系统。中性粒细胞渗入 MK 细胞质，贡献其表面的一部分 在出现存活且完整之前将膜附着到血小板上。我们的初步数据表明，中性粒细胞采取 在伸入过程中增加 MK 衍生的外泌体，并具有增强的迁移能力。建立在 根据这些结果，我们探索了这样的假设：伸入是一种新型的细胞间相互作用，可以调节 中性粒细胞的功能。 我们通过两个独立但互补的目标来检验这一假设。在目标 I 中，我们检查了以下效果： 穿入，特别是 MK 外泌体，对中性粒细胞效应功能、代谢和体内 中性粒细胞依赖性 K/BxN 血清转移关节炎中的迁移。在Aim II中，我们采用了整体贴装3D 骨髓成像、2 光子体内显微镜、特定 MK 缺失和潜在的伸入性 封锁以测试伸入性代表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，包括在实验性关节炎中。 这些研究将共同定义 MK 和中性粒细胞之间调节的新合作形式 中性粒细胞参与健康和疾病的能力。更一般地说，以我们最近的 鉴定 MKs 作为关节炎中 IL-1 的来源，这些研究继续加深对 MK 和中性粒细胞参与全身炎症性疾病。这些“高风险、高回报” 对以前被忽视的、在哺乳动物物种中广泛保守的生物过程的研究将确定 这是对伸入现象作为一种新的细胞内现象进行扩展研究的阶段。

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.