Abstract Background Intestinal fibrosis is a common complication of inflammatory bowel disease (IBD), resulting from the uncontrolled accumulation of extracellular matrix (ECM) deposited by fibroblasts. Janus kinases (JAK) inhibitors are a relatively novel therapeutic strategy in IBD, which show robust anti-inflammatory effects, but their potential effects on fibrosis have not been investigated. In this study, we explored the effects of JAK inhibition on fibroblasts and intestinal fibrosis. Methods The spatial distribution of fibroblast subsets in fibrotic tissues from Crohn’s disease (CD) patients was mapped using a 40-marker fibroblast-specific panel for imaging mass cytometry (IMC). Next, the activation of the JAK/STAT pathway in primary intestinal fibroblasts was evaluated using western blot and RNA-sequencing. Fibroblast reprogramming by JAK inhibitors (JAKi; upadacitinib, tofacitinib, filgotinib) was further evaluated by functional studies on ECM deposition and remodeling. Finally, the effects of JAK inhibition were tested in two acute colitis models (T-cell transfer, IL-10 knockout) and one chronic DSS model for intestinal fibrosis. Intestinal ECM deposition was evaluated by Sirius Red staining, while fibroblast subsets were evaluated by flow cytometry. Results Analysis of our scRNA-sequencing dataset from fibrostenotic CD tissue identified that ECM-producing fibroblasts expressing fibroblast activation protein (FAP) show high JAK-STAT3 activation. 1 Consistently, IMC confirmed distinct fibroblast subsets with high levels of pSTAT1 and pSTAT3 in fibrostentotic tissues. JAKi strongly suppressed JAK-STAT activation in a concentration-dependent manner in human intestinal fibroblasts. Notably, the three JAK inhibitors differed in their impact on ECM remodeling in vitro, with upadacitinib showing the strongest effect on collagen I gel contraction and reduction of FAP expression. In line with these in vitro findings, upadacitinib also altered ECM deposition in the colon of mice with chronic DSS-induced fibrosis. Furthermore, in both acute colitis models, intestinal fibroblast subsets (e.g. CD90+podoplanin+ fibroblasts) were reprogrammed following JAKi. Importantly, in vitro validation of these findings revealed that podoplanin was decreased in fibroblasts upon JAK inhibition. Conclusion JAK inhibition effectively suppressed JAK-STAT signaling in intestinal fibroblasts, reprogrammed fibroblast subsets, and decreased ECM remodeling in vitro and in vivo. within most assays, upadacitinib showed the strongest antifibrotic activity. Our study highlights the JAK-STAT pathway as a critical regulator of fibroblast plasticity in IBD and supports upadacitinib as a promising therapeutic strategy for intestinal fibrosis. Reference: 1. Ke, Bo-Jun et al. “Intercellular interaction between FAP+ fibroblasts and CD150+ inflammatory monocytes mediates fibrostenosis in Crohn’s disease.” The Journal of clinical investigation vol. 134,16 e173835. 23 Jul. 2024, doi:10.1172/JCI173835 Conflict of interest: Su, Jie: No conflict of interest van Os, Bram: No conflict of interest Ke, Bo-Jun: No conflict of interest de Winter, Sabine: No conflict of interest Danen, Erik: Voorneveld, Philip: Speaker fee: Galapagos, Janssen, Takeda, Ferring Advisory board: Galapagos, Takeda, BMS, AbbVie, Pfizer, Janssen, Lilly Grant: Alpha Sigma Hawinkels, Luuk: Consultancy fees from InnoSer Biosciences. Matteoli, Gianluca: No conflict of interest Barnhoorn, Marieke: Speaker fee from MedNet. This project was supported by an ECCO pioneer award.
Su et al. (Thu,) studied this question.