Extended Data Fig. 2: Pro-resolving fibroblast delivery enhances in vivo resolution of fibrosis.
From: Histological signatures map anti-fibrotic factors in mouse and human lungs
(A) Delivery of freshly FACS-sorted fibroblasts to mice for investigation of functional impact. Created with BioRender. Guo, J. https://BioRender.com/l13t441 (2025). (B) Impact of fibroblast subtype enrichment during peak fibrosis on downstream collagen content (left; n = 3 mice for post-injury day [PID] 21 and all baseline timepoints; n = 4 mice for all other treatments and timepoints) (Lin-: p = 0.294/0.438/0.750/0.688; Pro-Resolving: p = 0.043/0.049/0.696/0.688; ECM-Secreting: p = 0.600/0.873/0.696/0.688; for PID 28/35/42/49, respectively, vs. baseline), matrix architecture (middle; n = 5 mice) (Lin-: p = 0.035/0.004/0.027/0.851; Pro-Resolving: p < 0.0001/0.0001/0.0001/p = 0.0004; ECM-Secreting: p = 0.484/0.806/0.243/0.383; for PID 28/35/42/49, respectively, vs. baseline), and immature collagen staining (right; n = 5 mice) (Lin-: p = 0.125/0.636/0.502/0.913; Pro-Resolving: p = 0.005/0.179/0.306/0.710; ECM-Secreting: p = 0.009/0.001/0.706/0.036; for PID 28/35/42/49, respectively, vs. baseline). Pro-resolving fibroblasts help accelerate post-fibrotic resolution when enriched at PID 21. * indicates statistically significant difference from baseline at same timepoint (p < 0.05). (C) Immunofluorescence of instilled tdTomato+ fibroblasts after PID 21 indicates that both ECM-secreting and pro-resolving fibroblasts integrate within the interstitium, largely within less fibrotic areas. Orange arrows indicate subtype-positive instilled cells, while blue arrows indicate subtype-negative instilled cells. Results are representative of n = 3 independent experiments. (D) FACS quantification suggests that instilled fibroblasts proliferate from post-delivery day 1 to 7 (Pro-Resolving: p = 0.010/0.010; ECM-Secreting: p = 0.002/0.048; for post-delivery day 7/14, respectively, vs. day 1), with ECM-secreting fibroblasts losing their original phenotype during the post-fibrotic phase (Pro-Resolving: p = 0.355/0.140; ECM-Secreting: p < 0.0001/0.0001; for post-delivery day 7/14, respectively, vs. day 1) (n = 3 mice for post-delivery day 1 and 14; n = 4 mice for post-delivery day 7). * indicates statistically significant difference from post-delivery day 1 (p < 0.05). For panels B and D, p-values are based on ANOVA with post-hoc testing by Fisher’s least significant difference and Benjamini-Hochberg correction (all tests two-tailed), while all values are displayed as mean ± standard deviation.
