Fibroblasts are key effector cells in tissue remodeling. They remain persistently activated in fibrotic diseases, resulting in progressive deposition of extracellular matrix. Although fibroblast activation may be initiated by external factors, prolonged activation can induce an “autonomous,” self-maintaining profibrotic phenotype in fibroblasts. Accumulating evidence suggests that epigenetic alterations play a central role in establishing this persistently activated pathologic phenotype of fibroblasts. We demonstrated that in fibrotic skin of patients with systemic sclerosis (SSc), a prototypical idiopathic fibrotic disease, TGF-β induced the expression of DNA methyltransferase 3A (DNMT3A) and DNMT1 in fibroblasts in a SMAD-dependent manner to silence the expression of suppressor of cytokine signaling 3 (SOCS3) by promoter hypermethylation. Downregulation of SOCS3 facilitated activation of STAT3 to promote fibroblast-to-myofibroblast transition, collagen release, and fibrosis in vitro and in vivo. Reestablishment of the epigenetic control of STAT3 signaling by genetic or pharmacological inactivation of DNMT3A reversed the activated phenotype of SSc fibroblasts in tissue culture, inhibited TGF-β–dependent fibroblast activation, and ameliorated experimental fibrosis in murine models. These findings identify a pathway of epigenetic imprinting of fibroblasts in fibrotic disease with translational implications for the development of targeted therapies in fibrotic diseases.

CD19-targeting chimeric antigen receptor (CAR) T-cell therapy has shown remarkable outcomes in patients with systemic lupus erythematosus. The effects of CD19-targeting CAR T cells on organ manifestations in patients with systemic sclerosis have yet to be characterised. B cells have a central role in the pathogenesis of systemic sclerosis. We present a detailed analysis of the effects of CD19-targeting CAR T-cell therapy in patients with systemic sclerosis. Six patients with severe diffuse systemic sclerosis with an insufficient response to at least two treatments were consecutively recruited at the Department of Internal Medicine 3, University Hospital Erlangen (Erlangen, Germany) to receive CD19-targeting CAR T-cell treatment (1 × 10⁶ CAR T cells per kg bodyweight). Events were predefined by progression of interstitial lung disease, onset of congestive heart failure, onset of renal failure, onset of arterial hypertension, or initiation of new immunosuppressive or antifibrotic therapy. Event-free time or treatment intensification after study entry was the primary outcome. Key secondary outcomes included changes in the modified Rodnan Skin Score (mRSS), imaging (a component of the assessment of lung fibrosis), laboratory assessments, patient-reported outcomes, and a modified version of the American College of Rheumatology Composite Response Index in Systemic Sclerosis (ACR-CRISS), assessed at baseline, 3 months, 6 months, 9 months, and 12 months. Between April 20, 2022, and Nov 8, 2023, six patients with severe diffuse systemic sclerosis (median age 42 years [IQR 36-53]; four men and two women; all White European) were recruited and received CD19-targeted CAR T-cell therapy. The median follow-up time was 487 days (IQR 342-585). No events occurred within the observational period. Probability of improvement in the ACR-CRISS score increased to a median of 100% (IQR 100-100) at 6 months. Median mRSS decreased by 31% (IQR 29-38), corresponding to a median of 8 points (IQR 7-13) within 100 days. The extent of disease on CT scan decreased by a median of 4% (IQR 3-4) due to reduction of ground-glass opacities while the reticular pattern remained stable. Forced vital capacity improved by a median of 195 mL (IQR 18-275) at the latest observational timepoint. We provide the first evidence that CD19-targeting CAR T-cell therapy might intercept with the progression of fibrotic organ manifestations in patients with systemic sclerosis. Deutsche Forschungsgemeinschaft, Deutsche Krebshilfe, ELAN-Foundation Erlangen, IZKF Erlangen, and Bundesministerium für Bildung und Forschung.

Chimeric antigen receptor (CAR)-T cells are considered a powerful therapeutic tool to reset the immune system in patients with autoimmune diseases. Innovative trial designs are needed to allow feasible testing of the safety and efficacy of CAR-T cells in clinical studies. CASTLE (CAR-T cells in systemic B cell mediated autoimmune disease) is a phase 1/2a two-stage optimal design basket study that investigated the safety and efficacy of zorpocabtagene autoleucel (Zorpo-cel, also known as MB-CART19.1), an autologous CD19 CAR-T cell product, in patients with treatment-resistant systemic lupus erythematosus (SLE), systemic sclerosis (SSc) and idiopathic inflammatory myopathies (IIM). The primary safety outcome was the rate of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). The secondary clinical efficacy outcomes were remission of SLE according to DORIS criteria, no progression of interstitial lung disease in SSc and American College of Rheumatology (ACR) major/moderate response in IIM after 24 weeks. A total of 24 patients were enrolled (10 with SLE, 9 with SSc and 5 with IIM), all receiving a single infusion of Zorpo-cel after stopping immunosuppressive treatments and receiving standard lymphodepletion with cyclophosphamide and fludarabine. Primary and secondary endpoints of CASTLE were met. Regarding safety, no CRS higher than grade 2 and no ICANS occurred. Regarding efficacy, 22 of the 24 patients achieved predefined efficacy endpoints, with 9 out of 10 patients with SLE reaching DORIS remission, 9 out of 9 patients with SSc showing no disease progression, and 4 out of 5 patients with IIM reaching ACR major/moderate response. Furthermore, all patients remained free of glucocorticoids and any other immunosuppressive treatment over the entire observation period of 24 weeks. CASTLE suggests the feasibility, safety and efficacy of Zorpo-cel in three different autoimmune diseases and paves the way for conducting a pivotal study. ClinicalTrials.gov identifier: NCT06347718 , EudraCT identifier: 2022-001366-35 .

Transforming growth factor β (TGF-β) signaling is a core pathway of fibrosis, but the molecular regulation of the activation of latent TGF-β remains incompletely understood. Here, we demonstrate a crucial role of WNT5A/JNK/ROCK signaling that rapidly coordinates the activation of latent TGF-β in fibrotic diseases. WNT5A was identified as a predominant noncanonical WNT ligand in fibrotic diseases such as systemic sclerosis, sclerodermatous chronic graft-versus-host disease, and idiopathic pulmonary fibrosis, stimulating fibroblast-to-myofibroblast transition and tissue fibrosis by activation of latent TGF-β. The activation of latent TGF-β requires rapid JNK- and ROCK-dependent cytoskeletal rearrangements and integrin α _V (ITGAV). Conditional ablation of WNT5A or its downstream targets prevented activation of latent TGF-β, rebalanced TGF-β signaling, and ameliorated experimental fibrosis. We thus uncovered what we believe to be a novel mechanism for the aberrant activation of latent TGF-β in fibrotic diseases and provided evidence for targeting WNT5A/JNK/ROCK signaling in fibrotic diseases as a new therapeutic approach.