Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain.
Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
J Hepatol. 2023 Oct;79(4):1025-1036. doi: 10.1016/j.jhep.2023.05.045. Epub 2023 Jun 20.
BACKGROUND & AIMS: Ductular reaction expansion is associated with poor prognosis in patients with advanced liver disease. However, the mechanisms promoting biliary cell proliferation are largely unknown. Here, we identify neutrophils as drivers of biliary cell proliferation and the defective wound-healing response.
The intrahepatic localization of neutrophils was evaluated in patients with chronic liver disease. Neutrophil dynamics were analyzed by intravital microscopy and neutrophil-labeling assays in DDC-treated mice. Neutrophil depletion or inhibition of recruitment was achieved using a Ly6g antibody or a CXCR1/2 inhibitor, respectively. Mice deficient in PAD4 (peptidyl arginine deiminase 4) and ELANE/NE (neutrophil elastase) were used to investigate the mechanisms underlying ductular reaction expansion.
In this study we describe a population of ductular reaction-associated neutrophils (DRANs), which are in direct contact with biliary epithelial cells in chronic liver diseases and whose numbers increased in parallel with disease progression. We show that DRANs are immobilized at the site of ductular reaction for a prolonged period of time. In addition, liver neutrophils display a unique phenotypic and transcriptomic profile, showing a decreased phagocytic capacity and increased oxidative burst. Depletion of neutrophils or inhibition of their recruitment reduces DRANs and the expansion of ductular reaction, while mitigating liver fibrosis and angiogenesis. Mechanistically, neutrophils deficient in PAD4 and ELANE abrogate neutrophil-induced biliary cell proliferation, thus indicating the role of neutrophil extracellular traps and elastase release in ductular reaction expansion.
Overall, our study reveals the accumulation of DRANs as a hallmark of advanced liver disease and a potential therapeutic target to mitigate ductular reaction and the maladaptive wound-healing response.
Our results indicate that neutrophils are highly plastic and can have an extended lifespan. Moreover, we identify a new role of neutrophils as triggers of expansion of the biliary epithelium. Overall, the results of this study indicate that ductular reaction-associated neutrophils (or DRANs) are new players in the maladaptive tissue-healing response in chronic liver injury and may be a potential target for therapeutic interventions to reduce ductular reaction expansion and promote tissue repair in advanced liver disease.
在晚期肝病患者中，胆管反应扩张与预后不良相关。然而，促进胆管细胞增殖的机制在很大程度上尚不清楚。在这里，我们发现中性粒细胞是胆管细胞增殖和伤口愈合反应缺陷的驱动因素。
评估了慢性肝病患者肝内中性粒细胞的定位。通过活体显微镜和 DDC 处理的小鼠中的中性粒细胞标记测定分析中性粒细胞动力学。使用 Ly6g 抗体或 CXCR1/2 抑制剂分别实现中性粒细胞耗竭或募集抑制。使用 PAD4（肽基精氨酸脱亚氨酶 4）和 ELANE/NE（中性粒细胞弹性蛋白酶）缺陷小鼠来研究胆管反应扩张的机制。
在这项研究中，我们描述了一种与胆管反应相关的中性粒细胞（DRAN）群体，其与慢性肝病中的胆管上皮细胞直接接触，并且其数量随着疾病的进展而平行增加。我们表明，DRAN 在胆管反应部位长时间固定。此外，肝中性粒细胞表现出独特的表型和转录组谱，表现出吞噬能力降低和氧化爆发增加。中性粒细胞耗竭或抑制其募集可减少 DRAN 和胆管反应的扩张，同时减轻肝纤维化和血管生成。从机制上讲，缺乏 PAD4 和 ELANE 的中性粒细胞可消除中性粒细胞诱导的胆管细胞增殖，从而表明中性粒细胞细胞外陷阱和弹性蛋白酶释放在胆管反应扩张中的作用。
总体而言，我们的研究揭示了 DRAN 的积累是晚期肝病的一个标志，并且是减轻胆管反应和适应性伤口愈合反应的潜在治疗靶标。
我们的结果表明，中性粒细胞具有高度的可塑性并且可以具有延长的寿命。此外，我们确定了中性粒细胞作为胆管上皮细胞扩张的触发因素的新作用。总体而言，这项研究的结果表明，胆管反应相关的中性粒细胞（或 DRAN）是慢性肝损伤中适应性组织修复反应的新参与者，并且可能是减少胆管反应扩张和促进晚期肝病组织修复的潜在治疗干预靶点。
