Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands.
School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands.
Am J Physiol Gastrointest Liver Physiol. 2021 May 1;320(5):G689-G699. doi: 10.1152/ajpgi.00064.2020. Epub 2021 Feb 17.
Intestinal barrier dysfunction is a pathogenic hallmark in Crohn's disease (CD). Identifying key players that regulate intestinal barrier may provide novel leads for therapeutic intervention. Interleukin-28A (IL-28A) is a newly identified IL-10/interferon cytokine family member, with its most implicated function being antiviral and anti-proliferative properties. However, the role and underlying mechanisms of IL-28A in the regulation of epithelial barrier in CD remain so far unexplored. IL-28A levels were measured in the plasma and biopsies of CD patients and healthy subjects. CD patient-derived intestinal organoids were characterized by differentiation gene markers and then exposed to TNF-α, IFN-γ, IL-1β or LPS, or IL-28A with or without GLPG0634 (filgotinib). Epithelial permeability was assessed by FITC-D4 flux. Expression of junctional components was analyzed by qRT-PCR, immunofluorescence staining, or Western blotting. JAK-STAT activity was analyzed by Western blotting. IL-28A levels were significantly increased in the plasma and biopsies from active patients with CD as compared with healthy subjects. IL-28A and its receptor complex IL-28AR/IL-10R2 were detected in CD patient-derived intestinal organoids and showed a selective response to IFN-γ exposure. IL-28A triggered epithelial barrier disruption and accompanied by reduced ZO-1 and E-cadherin expression. This effect was mediated by JAK-STAT1 pathway. Pre-incubation with the JAK1 inhibitor filgotinib ameliorated the barrier dysfunction induced by IL-28A. These results identified IL-28A as a novel regulator of epithelial barrier function and could be a putative target for CD treatment. We provide novel basic evidence that restoring intestinal barrier is a potential mechanism that contributes to the clinical benefits of JAK1 inhibitor in patients with CD. IL-28A levels were significantly increased in the plasma and biopsies from active patients with CD as compared with healthy subjects. IFN-γ exposure stimulated IL-28A expression in intestinal organoids. Partially mimicking the effect of IFN-γ, IL-28A impaired epithelial barrier function and disrupted junctional components through the activation of JAK-STAT1 signaling, whereas JAK1 inhibitor ameliorated the above-mentioned effects of IL-28A. These findings highlight the newly identified cytokine IL-28A as a novel contributor to CD pathogenesis and could be a putative target for CD treatment. We also provide new evidence for potential applications of JAK inhibition in CD therapy.
肠道屏障功能障碍是克罗恩病（CD）的发病标志。鉴定出调节肠道屏障的关键因子可能为治疗干预提供新的线索。白细胞介素-28A（IL-28A）是一种新发现的 IL-10/干扰素细胞因子家族成员，其最主要的功能是抗病毒和抗增殖特性。然而，IL-28A 在 CD 中调节上皮屏障的作用和潜在机制迄今仍未得到探索。测量了 CD 患者和健康受试者的血浆和活检中的 IL-28A 水平。CD 患者来源的肠类器官通过分化基因标记进行了特征描述，然后暴露于 TNF-α、IFN-γ、IL-1β 或 LPS，或 IL-28A 加或不加 GLPG0634（filgotinib）。通过 FITC-D4 通量评估上皮通透性。通过 qRT-PCR、免疫荧光染色或 Western blot 分析连接成分的表达。通过 Western blot 分析 JAK-STAT 活性。与健康受试者相比，处于活动期的 CD 患者的血浆和活检中 IL-28A 水平显著升高。在 CD 患者来源的肠类器官中检测到 IL-28A 和其受体复合物 IL-28AR/IL-10R2，并对 IFN-γ 暴露表现出选择性反应。IL-28A 触发上皮屏障破坏，并伴有 ZO-1 和 E-钙粘蛋白表达减少。这种作用是由 JAK-STAT1 途径介导的。用 JAK1 抑制剂 filgotinib 预孵育可改善 IL-28A 诱导的屏障功能障碍。这些结果表明 IL-28A 是上皮屏障功能的新调节剂，可能是 CD 治疗的潜在靶点。我们提供了新的基础证据，表明恢复肠道屏障是 JAK1 抑制剂在 CD 患者中发挥临床益处的潜在机制。与健康受试者相比，处于活动期的 CD 患者的血浆和活检中 IL-28A 水平显著升高。IFN-γ 暴露刺激肠类器官中 IL-28A 的表达。部分模拟 IFN-γ 的作用，IL-28A 通过激活 JAK-STAT1 信号通路损害上皮屏障功能并破坏连接成分，而 JAK1 抑制剂改善了 IL-28A 的上述作用。这些发现强调了新发现的细胞因子 IL-28A 是 CD 发病机制的新贡献者，可能是 CD 治疗的潜在靶点。我们还为 JAK 抑制在 CD 治疗中的潜在应用提供了新的证据。
