Panel A shows histological images and bar graphs with the y-axis representing Fibrotic area (percent) and the x-axis representing WT to WT, WT to Ifnlr1 minus/minus, Ifnlr1 minus/minus to WT, and Ifnlr1 minus/minus to Ifnlr1 minus/minus groups. Panel B shows immunohistochemistry images and bar graphs with the y-axis representing Relative mean optical density and the x-axis representing WT to WT, WT to Ifnlr1 minus/minus, Ifnlr1 minus/minus to WT, and Ifnlr1 minus/minus to Ifnlr1 minus/minus groups. Panel C shows bar graphs with the y-axis representing Relative mRNA levels (fold changes) and the x-axis representing WT to WT, WT to Ifnlr1 minus/minus, Ifnlr1 minus/minus to WT, and Ifnlr1 minus/minus to Ifnlr1 minus/minus groups. Panel D shows violin plots with the y-axis representing Expression and the x-axis representing different kidney cell populations for IFNLR1 and IL10RB in dataset GSE145173. Panel E shows violin plots with the y-axis representing Expression and the x-axis representing Fibroblasts and Myofibroblasts for IFNLR1 and IL10RB in dataset GSE211785. Panel F shows violin plots with the y-axis representing Expression and the x-axis representing Fibroblasts for Ifnlr1 and Il10rb in dataset GSE198261. Panel G shows violin plots with the y-axis representing Expression and the x-axis representing Fibroblasts for Ifnlr1 and Il10rb in dataset GSE197266. Panel H shows a workflow diagram illustrating renal fibroblast isolation, treatment with phosphate-buffered saline or IFN-lambda2 for 24 hours, followed by Western blot and RT-qPCR analyses. Panel I shows immunoblot images displaying alpha-SMA, Fibronectin, Vimentin, and GAPDH protein levels in renal fibroblasts under different treatment conditions. Panel J shows bar graphs with the y-axis representing Relative mRNA levels (fold changes) and the x-axis representing WT plus phosphate-buffered saline, WT plus IFN-lambda2, Ifnlr1 minus/minus plus phosphate-buffered saline, and Ifnlr1 minus/minus plus IFN-lambda2 groups. Panel K shows histological images and bar graphs with the y-axis representing Fibrotic area (percent) or Relative mean optical density for Ifnlr1 f/f Sham, Ifnlr1 f/f; Col1a2-Cre Sham, Ifnlr1 f/f UUO, and Ifnlr1 f/f; Col1a2-Cre UUO groups. Panel L shows bar graphs with the y-axis representing Relative mRNA levels (fold changes) for Ifnlr1 f/f Sham, Ifnlr1 f/f; Col1a2-Cre Sham, Ifnlr1 f/f UUO, and Ifnlr1 f/f; Col1a2-Cre UUO groups.
IFN-λ induces renal fibrosis in mice by directly targeting renal fibroblasts. (A–C) WT and Ifnlr1−/− recipient mice were lethally irradiated before being reconstituted with donor BM cells from either WT or Ifnlr1−/− donor mice to generate BM chimeric mice. Mice were subjected to a UUO surgery, and kidneys were harvested 7 days later (n = 6). (A) Representative images and quantitative analysis of fibrotic area in kidneys of BM chimeric mice after UUO surgery, assessed by Masson’s trichrome and PSR staining (scale bars = 50 μm). (B) Representative IHC images and corresponding quantification of α-SMA and fibronectin MOD in kidneys of BM chimeric mice following UUO (scale bars = 50 μm). (C) mRNA levels of Acta2, fibronectin, and vimentin in the kidneys were measured by RT-qPCR. (D and E) scRNA-seq analysis of human kidneys with renal fibrosis (GSE145173 and GSE211785) revealed IFNLR1 and IL10RB expression in kidney cell populations. (F and G) scRNA-seq analysis from UUO mouse kidneys (GSE198261 and GSE197266) demonstrated Ifnlr1 and Il10rβ expression in renal fibroblasts. (H) Primary renal fibroblasts isolated from WT and Ifnlr1−/− mice were treated with or without 100 ng/ml IFN-λ2 for 24 h, followed by western blot and RT-qPCR analyses. (I) Western blot analysis of α-SMA, fibronectin, and vimentin protein expression levels in renal fibroblasts. GAPDH was employed as a loading control. (J) mRNA levels of Acta2, fibronectin, and vimentin in renal fibroblasts were measured by RT-qPCR (n = 4). (K and L) Fibroblast-specific Ifnlr1 knockout mice (Ifnlr1f/f; Col1a2-Cre) and their littermate control mice (Ifnlr1f/f) were subjected to sham or UUO surgery, and kidneys were collected on day 7 (n = 6). (K) Representative images and quantitative analysis for Masson’s trichrome, PSR, α-SMA, and fibronectin staining in kidneys of Ifnlr1f/f and Ifnlr1f/f; Col1a2-Cre mice following sham or UUO surgery (scale bars = 50 μm). (L) RT-qPCR analysis of Acta2, fibronectin, and vimentin mRNA levels in kidneys of Ifnlr1f/f and Ifnlr1f/f; Col1a2-Cre after sham or UUO surgery. Data in A–C and J–L are pooled from two independent experiments. Data in H and I are representative of two independent experiments. Data in D–G were adapted from indicated scRNA-seq dataset. Data are presented as mean ± SEM. **P < 0.01, ***P < 0.001, ****P < 0.0001, by two-way ANOVA with Tukey’s multiple-comparison test. MOD, mean OD. Source data are available for this figure: SourceData F3.