Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA.
Department of Cardiovascular Medicine, Xiangya Hospital, Changsha, China.
J Leukoc Biol. 2019 Jun;105(6):1225-1234. doi: 10.1002/JLB.3VMA0918-374R. Epub 2019 Mar 25.
Neutrophil extracellular traps (NETs) are implicated in autoimmune, thrombotic, malignant, and inflammatory diseases; however, little is known of their endogenous regulation under basal conditions. Inflammatory effects of neutrophils are modulated by extracellular purines such as adenosine (ADO) that is inhibitory or ATP that generally up-regulates effector functions. In order to evaluate the effects of ADO on NETs, human neutrophils were isolated from peripheral venous blood from healthy donors and stimulated to make NETs. Treatment with ADO inhibited NET production as quantified by 2 methods: SYTOX green fluorescence and human neutrophil elastase (HNE)-DNA ELISA assay. Specific ADO receptor agonist and antagonist were tested for their effects on NET production. The ADO receptor (A R) agonist CSG21680 inhibited NETs to a similar degree as ADO, whereas the A R antagonist ZM241385 prevented ADO's NET-inhibitory effects. Additionally, CD73 is a membrane bound ectonucleotidase expressed on mesenchymal stromal cells (MSCs) that allows manipulation of extracellular purines in tissues such as bone marrow. The effects of MSCs on NET formation were evaluated in coculture. MSCs reduced NET formation in a CD73-dependent manner. These results imply that extracellular purine balance may locally regulate NETosis and may be actively modulated by stromal cells to maintain tissue homeostasis.
中性粒细胞胞外诱捕网（NETs）与自身免疫、血栓、恶性和炎症性疾病有关；然而，人们对其在基础条件下的内源性调节知之甚少。中性粒细胞的炎症作用可被细胞外嘌呤（如腺苷，具有抑制作用）或 ATP 调节，后者通常可上调效应功能。为了评估 ADO 对 NETs 的影响，我们从健康供者的外周静脉血中分离出中性粒细胞，并刺激其生成 NETs。通过 2 种方法定量检测 ADO 对 NET 生成的抑制作用：SYTOX 绿色荧光和人中性粒细胞弹性蛋白酶（HNE）-DNA ELISA 检测。测试了特定的 ADO 受体激动剂和拮抗剂对 NET 生成的影响。ADO 受体（A R）激动剂 CSG21680 对 NETs 的抑制作用与 ADO 相似，而 A R 拮抗剂 ZM241385 则阻止了 ADO 的 NET 抑制作用。此外，CD73 是一种表达在间充质基质细胞（MSCs）上的膜结合核苷酸酶，它允许对骨髓等组织中的细胞外嘌呤进行操作。我们评估了 MSC 对 NET 形成的影响。MSC 以 CD73 依赖的方式减少 NET 的形成。这些结果表明，细胞外嘌呤平衡可能局部调节 NETosis，并且可能被基质细胞主动调节以维持组织内稳态。
