DIFFERENTIATION AND FUNCTION OF MONOCYTES AND MACROPHAGES

项目摘要 尽管新冠肺炎的发病机制尚不清楚，但细胞因子 风暴和凝血改变导致了不利的疾病发病机制。这两种细胞因子 单核细胞活化可能是产生和促进凝血的重要机制之一。例如，单核细胞 血液中的中央白细胞表达组织因子(F3)，并启动凝血，这一活动促进 埃博拉病毒和艾滋病毒感染的共病。COVID患者血浆中似乎最显著升高的一种细胞因子 患者为IL-6。与IL-6在细胞因子风暴中的潜在重要性一致，我们的初步数据显示 血液中的单核细胞是COVID白细胞中IL-6的主要来源，并且它们的产生 IL-6的表达与疾病的不良进展呈正相关。令人惊讶的是，尽管单核细胞产生 COVID患者单核细胞亚群中不存在细胞因子等典型激活特征。 特别是，在产生IL-6的单核细胞中诱导功能性组织因子的情况很少，甚至没有。这是 与来自健康受试者的对照单核细胞相比，体外用脂多糖或雷西莫德处理的单核细胞形成鲜明对比。vt.给出 新冠肺炎凝血功能改变在不良心绞痛发病机制中的作用 由于IL-6的表达非常强劲，我们特别惊讶的是组织因子没有 诱导性。总体而言，新冠肺炎患者单核细胞激活的刺激似乎与 也在细胞因子产生细胞中诱导组织因子的规范反应，或者可能是 能够激活组织因子途径的单核细胞缺失或在提取的新冠肺炎PBMC中缺失。这个 这项工作的首要目标是使用稳健的纵向数据集来定义是否促炎 血液中单核细胞亚群的激活与疾病的严重程度相关，并确定核心特征 这样的激活。我们还将进行探索性分析，寻找导致这种激活的信号。 我们建议的一个关键资源是获得冷冻的PBMC、血清、血浆和全血银行，其中 对300名住院的不同疾病严重程度的新冠肺炎患者进行纵向采血 巴恩斯犹太医院。这家银行是由机构临床和翻译机构建立的 华盛顿大学医学院的研究项目。来自这家银行的资源将与 用我们实验室中50名对照参与者的冰冻PBMC和HIV受试者的PBMC， 其中单核细胞的激活状态将与来自COVID患者的单核细胞进行比较。

Project Summary Although much remains unclear with respect to the pathogenesis of COVID-19, the possibilities that cytokine storm and altered coagulation contribute to adverse disease pathogenesis have emerged. Both the cytokine output and promotion of coagulation may be mediated by activated monocytes. Monocytes, for instance, are the central leukocyte in blood to express tissue factor (F3) and initiate coagulation and this activity promotes comorbidity in Ebola and HIV infections. One cytokine that seems most notably elevated in plasma of COVID patients is IL-6. In keeping with the potential importance of IL-6 in cytokine storm, our preliminary data reveal that blood monocytes, of all subsets, are a major source of IL-6 in COVID leukocytes and that their production of IL-6 positively correlates with adverse disease progression. Surprisingly, though monocytes produce cytokines, other features of canonical activation were not present in monocyte subsets of COVID patients. Particularly, induction of functional tissue factor in IL-6-producing monocytes was minimal to absent. This was in striking contrast to control monocytes from healthy subjects treated ex vivo with LPS or resiquimod. Given the clinical concern that coagulation may be altered in COVID-19 and contribute to pathogenesis of adverse disease and given the very robust expression of IL-6, we were especially surprised that tissue factor was not induced. Overall, it appears that the stimulus for activation of monocytes in COVID-19 patients is distinct from canonical responses that also induce tissue factor in cytokine-producing cells, or perhaps a subset of monocytes able to activate the tissue factor pathway is missing or in extracted COVID-19 PBMCs. The overarching aim of this work is to define, using a robust longitudinal dataset, whether proinflammatory activation of monocyte subsets in blood associates with disease severity and to define the core characteristics of such activation. We will also carry out exploratory analyses in search of signals that lead to such activation. A key resource for our proposal is access to a bank of frozen PBMC, serum, plasma and whole blood in which longitudinal blood draws are being collected on 300 COVID-19 patients of differing disease severity admitted to Barnes Jewish Hospital. This bank has been established by the Institutional Clinical and Translational Research program at Washington University School of Medicine. Resources from this bank will be coupled with a stock of frozen PBMCs from >50 control participants in our laboratory and PBMCs from HIV subjects, where the state of monocyte activation will be compared with that of monocytes derived from COVID patients.