Center for Gastrointestinal Biology, Morphology Department, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
J Leukoc Biol. 2020 Oct;108(4):1199-1213. doi: 10.1002/JLB.1MA0420-634R. Epub 2020 May 18.
Neutrophils were classically described as powerful effectors of acute inflammation, and their main purpose was assumed to be restricted to pathogen killing through production of oxidants. As consequence, neutrophils also may lead to significant collateral damage to the healthy tissues, and after performing these tasks, these leukocytes are supposed to die within tissues. However, there is a growing body of evidence showing that neutrophils also play a pivotal role in the resolution phases of inflammation, because they can modulate tissue environment due to secretion of different kind of cytokines. Drug-induced liver injury (DILI) is a worldwide concern being one of the most prevalent causes of liver transplantation, and is well established that there is an intense neutrophil recruitment into necrotic liver during DILI. However, information if such abundant granulocyte infiltration is also linked to the tissue repairing phase of hepatic injury is still largely elusive. Here, we investigated the dynamics of neutrophil trafficking within blood, bone marrow, and liver during hepatic inflammation, and how changes in their gene expression profile could drive the resolution events during acetaminophen (APAP)-induced liver injury. We found that neutrophils remained viable during longer periods following liver damage, because they avidly patrolled necrotic areas and up-regulated pro-resolutive genes, including Tgfb, Il1r2, and Fpr2. Adoptive transference of "resolutive neutrophils" harvested from livers at 72 h after injury to mice at the initial phases of injury (6 h after APAP) significantly rescued organ injury. Thus, we provide novel insights on the role of neutrophils not only in the injury amplification, but also in the resolution phases of inflammation.
中性粒细胞被经典地描述为急性炎症的强大效应物,其主要目的被认为仅限于通过产生氧化剂来杀死病原体。因此,中性粒细胞也可能导致健康组织的严重附带损伤,并且在执行这些任务后,这些白细胞应该在组织内死亡。然而,越来越多的证据表明,中性粒细胞也在炎症的消退阶段发挥关键作用,因为它们可以通过分泌不同类型的细胞因子来调节组织环境。药物性肝损伤(DILI)是一个全球性的问题,是肝移植的最常见原因之一,并且已经确定在 DILI 期间,大量中性粒细胞会募集到坏死的肝脏中。然而,关于这种丰富的粒细胞浸润是否也与肝损伤的组织修复阶段有关的信息仍然很大程度上难以捉摸。在这里,我们研究了中性粒细胞在肝炎症期间在血液、骨髓和肝脏中的迁移动态,以及它们的基因表达谱的变化如何驱动对乙酰氨基酚(APAP)诱导的肝损伤的消退事件。我们发现,中性粒细胞在肝损伤后较长时间内仍然保持存活,因为它们在坏死区域中积极巡逻,并上调了促消退基因,包括 Tgfb、Il1r2 和 Fpr2。从损伤后 72 小时的肝脏中采集的“促消退中性粒细胞”在损伤的初始阶段(APAP 后 6 小时)被过继转移到小鼠体内,可显著挽救器官损伤。因此,我们提供了关于中性粒细胞在炎症消退阶段的作用的新见解,不仅在损伤放大中,而且在炎症消退阶段也有作用。