The soluble factor milieu in idiopathic pulmonary fibrosis dysregulates epithelial differentiation
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 u...
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| Published in: | The FASEB journal Vol. 38; no. 19; pp. e70077 - n/a |
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| Main Authors: | , , , , , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
United States
15-10-2024
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| Subjects: | |
| Online Access: | Get full text |
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| Summary: | 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.
Schematic overview of the effect of an IPF‐like soluble factor environment on epithelial differentiation. The soluble factor milieu in IPF is altered, including elevated levels of CCL2, IL‐1β, IL‐4, IL‐8, IL‐13, IL‐33, TGF‐β, TNFα, and TSLP. We mimicked this using the IPF cocktail and found that it altered IL‐6, VEGF‐C, Wnt, and HSP27 signaling among others. Moreover, the normal differentiation process during regeneration is disturbed in the presence of the IPF soluble factor environment, which is partially due to changes in Wnt signaling. In combination with other signaling pathways involved (marked by ‘?’), these altered signaling pathways lead to a decreased presence of mature AT2 cells, club cells, and ciliated cells in IPF (created using BioRender.com). |
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| Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 0892-6638 1530-6860 1530-6860 |
| DOI: | 10.1096/fj.202302405RR |