DIFFERENTIATION AND FUNCTION OF MONOCYTES AND MACROPHAGES

项目摘要 尽管关于COVID-19的发病机制仍有很多不清楚的地方，但细胞因子 风暴和改变凝血有助于不利疾病发病机制已经出现。细胞因子 凝血的输出和促进可由活化的单核细胞介导。例如，单核细胞是 血液中的中心白细胞表达组织因子（F3）并启动凝血，并且这种活性促进 埃博拉病毒和艾滋病毒感染的并发症。一种在COVID患者血浆中似乎最显著升高的细胞因子 患者是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， 血液单核细胞是COVID白细胞中IL-6的主要来源， IL-6的水平与疾病的不良进展呈正相关。令人惊讶的是，虽然单核细胞产生 细胞因子，典型激活的其他特征在COVID患者的单核细胞亚群中不存在。 特别地，在产生IL-6的单核细胞中功能性组织因子的诱导是最小的至不存在。这是 这与来自用LPS或瑞喹莫特离体处理的健康受试者的对照单核细胞形成鲜明对比。给定 临床上关注的是，COVID-19可能会改变凝血功能，并导致不良反应的发病机制， 疾病和非常强大的表达IL-6，我们特别惊讶的是，组织因子不是 诱导。总的来说，COVID-19患者中单核细胞活化的刺激似乎不同于 典型的反应，也诱导组织因子在精氨酸生产细胞，或可能的子集， 能够激活组织因子途径的单核细胞缺失或在提取的COVID-19 PBMC中。的 这项工作的首要目标是使用一个强大的纵向数据集来定义， 血液中单核细胞亚群的活化与疾病的严重程度相关， 这样的激活。我们还将进行探索性分析，以寻找导致这种激活的信号。 我们提案的一个关键资源是获得冷冻PBMC、血清、血浆和全血库， 正在对300名不同疾病严重程度的COVID-19患者进行纵向抽血， 巴恩斯犹太医院。该银行由临床和翻译机构建立， 华盛顿大学医学院的研究项目。这家银行的资源将与 使用来自我们实验室中>50名对照参与者的冷冻PBMC储备和来自HIV受试者的PBMC， 其中将单核细胞活化状态与来自COVID患者的单核细胞的活化状态进行比较。

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.