Impact of emperipolesis on platelet function

伸入对血小板功能的影响

• 批准号: 10705905
• 负责人: Peter A Nigrovic
• 金额: $ 2.57万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-10-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10705905
• 关键词: Impact; emperipolesis; platelet; function

Project Summary Megakaryocytes (MK) have been known for decades to engage in an unusual behavior termed emperipolesis, whereby leukocytes – principally neutrophils – appear intact within the MK cytoplasm. Emperipolesis is conserved across mammalian species. It is observed in normal marrow but becomes particularly prevalent under conditions of increased platelet demand, but its mechanisms and functions remain obscure. Using a new in vitro model system, we found that emperipolesis represents a high- throughput interaction whereby neutrophils passage rapidly through MKs. During this transit, neutrophil lipid membranes merge with the MK demarcation membrane system (DMS) and thereby contribute membrane directly to MKs themselves and to the resulting platelets, both in vitro and in vivo. One implication of this finding is that some circulating platelets represent hybrids, featuring both MK and neutrophil components. The goal of this proposal is to begin to understand the physiological function of this novel biology. Together with experienced MK/platelet collaborators Dr. Italiano and Dr. Flaumenhaft, we propose two Aims. Aim I characterizes the process of protein transfer from neutrophils to platelets via emperipolesis, using live cell imaging and electron microscopy, and defines the proteins transferred from neutrophils to platelets via SILAC mass spectrometry. Aim II pursues our preliminary data that hybrid platelets are likely to exhibit enhanced procoagulant function using in vitro assays of platelet function and in vivo imaging of platelet accumulation in growing thrombi. Together, these studies will initiate a novel of research into the biology of emperipolesis, illuminating a surprising pathway of interaction between the immune and hematopoietic systems and defining a previously unappreciated mechanism that has the potential to powerfully modulate platelet function. These “high risk, high reward” studies of a process observed across mammalian species fits well within the mandate of FOA PA-19-049 New Research Directions that Advance the NHLBI Strategic Vision Normal Biology to “clarify biological processes that are both present in healthy humans and likely to be relevant in HLBS disorders…” to set the stage for an extended investigation of this phenomenon.

项目摘要 巨核细胞（MK）几十年来一直被认为参与一种称为 在MK细胞质内，白细胞-主要是中性粒细胞-表现为完整。 在哺乳动物物种中，帝国主义是保守的。在正常骨髓中观察到， 在血小板需求增加的情况下尤其普遍，但其机制和功能 保持模糊。使用一种新的体外模型系统，我们发现帝国主义代表了一种高- 通量相互作用，由此中性粒细胞快速通过MK。在此过程中，中性粒细胞脂质 膜与MK分界膜系统（DMS）合并，从而有助于膜 在体外和体内直接作用于MK本身和所产生的血小板。其中一个含义是 发现一些循环血小板代表混合物，具有MK和中性粒细胞成分。 这个提议的目标是开始了解这种新生物的生理功能。 与经验丰富的MK/血小板合作者Dr. Italiano和Dr. Flaumenhaft一起，我们提出了两个目标。 目的研究中性粒细胞经血小板转运蛋白的过程， 细胞成像和电子显微镜，并确定从中性粒细胞转移到血小板的蛋白质，通过 SILAC质谱法。目的二追求我们的初步数据，杂交血小板可能表现出 使用血小板功能的体外测定和血小板的体内成像来增强促凝血功能 在生长的血栓中积聚。 总之，这些研究将开创一个新的研究领域，即帝国主义的生物学， 免疫和造血系统之间的相互作用的令人惊讶的途径，并定义了一个以前的 一种未被重视的机制，有可能有力地调节血小板功能。这些“高风险， 对哺乳动物物种中观察到的过程进行的“高回报”研究非常符合FOA的任务规定 PA-19-049推进NHLBI战略愿景的新研究方向正常生物学“澄清 这些生物过程既存在于健康人身上，也可能与HLBS疾病有关。 为深入研究这一现象奠定基础