Therapeutic effect of nintedanib in orbital fibroblasts in patients with Graves’ orbitopathy

Nintedanib is a potent antifibrotic angiokinase inhibitor approved for various fibrotic lung diseases. Potential therapeutic efficacy of nintedanib in various inflammatory diseases is under investigation. In this study, we investigated the therapeutic effect of nintedanib on adipogenesis and fibrosis in orbital fibroblasts in patients with Graves’ orbitopathy (GO). Primary orbital fibroblasts were cultured from orbital connective tissue of patients with GO and healthy controls. The cells were pretreated with nintedanib before stimulation with either interleukin (IL)-1β, transforming growth factor (TGF)-β, insulin-like growth factor-1, or IL-11. Fibrosis-related and intracellular signaling protein expressions were assessed using western blotting. Hyaluronan and procollagen concentrations were quantified using enzyme-linked immunosorbent assay. Adipogenesis was quantified by Oil Red O staining and the levels of adipogenic transcription factors were determined by Western blot. TGF-β-induced fibronectin and collagen 1/3 protein expression was abrogated by nintedanib treatment. Nintedanib decreased the phosphorylation of signal transducer and activator of transcription 3, SMAD 2/3, Akt, c-Jun N-terminal kinase, and extracellular regulated protein kinase. Exposure to nintedanib hindered adipocyte differentiation and expression of adipogenic transcription factors, including peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein α/β, adipocyte protein 2, adiponectin, and leptin. Additionally, nintedanib reduced hyaluronan and procollagen secretion. Nintedanib suppressed profibrotic protein production, adipogenesis, and hyaluronan production in <i>in vitro</i>. These findings indicate the potential therapeutic efficacy of nintedanib in GO management.