Department of Molecular Pharmacology, University of Groningen, Groningen, the Netherlands.
Groningen Research Institute for Asthma and COPD (GRIAC), University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
FASEB J. 2024 Oct 15;38(19):e70077. doi: 10.1096/fj.202302405RR.
In idiopathic pulmonary fibrosis (IPF), epithelial abnormalities are present including bronchiolization and alveolar cell dysfunction. We hypothesized that the IPF microenvironment disrupts normal epithelial growth and differentiation. We mimicked the soluble factors within an IPF microenvironment using an IPF cocktail (IPFc), composed of nine factors which are increased in IPF lungs (CCL2, IL-1β, IL-4, IL-8, IL-13, IL-33, TGF-β, TNFα, and TSLP). Using IPFc, we asked whether the soluble factor milieu in IPF affects epithelial growth and differentiation and how IPFc compares to TGF-β alone. Epithelial growth and differentiation were studied using mouse lung organoids (primary Epcam+ epithelial cells co-cultured with CCL206 fibroblasts). Organoids exposed to IPFc and TGF-β were re-sorted into epithelial and fibroblast fractions and subjected to RNA sequencing. IPFc did not affect the number of organoids formed. However, pro-surfactant protein C expression was decreased. On these parameters, TGF-β alone had similar effects. However, RNA sequencing of re-sorted organoids revealed that IPFc and TGF-β had distinct effects on both epithelial cells and fibroblasts. IPFc upregulated goblet cell markers, whereas these were inhibited by TGF-β. Although both IPFc and TGF-β increased extracellular matrix gene expression, only TGF-β increased myofibroblast markers. VEGF-C and Wnt signaling were among the most differentially regulated signaling pathways by IPFc versus TGF-β. Interestingly, Wnt pathway activation rescued Sftpc downregulation induced by IPFc. In conclusion, IPFc alters epithelial differentiation in a way that is distinct from TGF-β. Alterations in Wnt signaling contribute to these effects. IPFc may be a more comprehensive representation of the soluble factor microenvironment in IPF.
在特发性肺纤维化（IPF）中，上皮细胞异常存在，包括细支气管化生和肺泡细胞功能障碍。我们假设 IPF 微环境会破坏正常的上皮细胞生长和分化。我们使用 IPF 鸡尾酒（IPFc）模拟 IPF 微环境中的可溶性因子，该鸡尾酒由在 IPF 肺中增加的九个因子组成（CCL2、IL-1β、IL-4、IL-8、IL-13、IL-33、TGF-β、TNFα 和 TSLP）。使用 IPFc，我们询问 IPF 中的可溶性因子环境是否会影响上皮细胞的生长和分化，以及 IPFc 与单独的 TGF-β相比如何。使用小鼠肺类器官（与 CCL206 成纤维细胞共培养的初级 Epcam+上皮细胞）研究上皮细胞的生长和分化。将暴露于 IPFc 和 TGF-β的类器官重新分为上皮和成纤维细胞部分，并进行 RNA 测序。IPFc 不影响形成的类器官数量。然而，表面活性剂蛋白 C 的表达减少。在这些参数上，TGF-β 单独具有相似的作用。然而，重新分类的类器官的 RNA 测序表明，IPFc 和 TGF-β对上皮细胞和成纤维细胞都有不同的作用。IPFc 上调杯状细胞标志物，而 TGF-β 抑制这些标志物。尽管 IPFc 和 TGF-β均增加细胞外基质基因表达，但只有 TGF-β增加肌成纤维细胞标志物。VEGF-C 和 Wnt 信号通路是 IPFc 与 TGF-β相比差异调节最多的信号通路之一。有趣的是，Wnt 通路的激活挽救了 IPFc 诱导的 Sftpc 下调。总之，IPFc 以与 TGF-β不同的方式改变上皮细胞分化。Wnt 信号通路的改变促成了这些影响。IPFc 可能更全面地代表了 IPF 中的可溶性因子微环境。
