Abstract
BACKGROUND: EW-7197, a potent oral ALK5 inhibitor, was assessed for its impact on transforming growth factor beta 1 (TGF-β1)-induced fibrosis in a three-dimensional (3D) renal fibrosis-on-a-chip and a mouse model. The evaluation included tubular epithelial- mesenchymal transition, angiogenesis, and inflammatory cytokine expression. METHODS: In a 3D renal fibrosis-on-a-chip model, three cell types(kidney fibroblasts, human proximal tubular cells, and human umbilical vein endothelial cells) were cultured and treated with TGF-β1 and EW-7197. Alpha smooth muscle actin (α-SMA) and keratin 8 (KRT-8) was assessed, angiogenesis observed via confocal microscopy, and cytokine levels measured by polymerase chain reaction, immunoassay, and enzyme-linked immunosorbent assay. In a cisplatin-induced renal fibrosis mouse model, blood urea nitrogen levels, TGF-β, and Smad 2/3 were determined, and fibrosis was assessed with Masson's trichrome stain. RESULTS: The α-SMA expression was significantly lower in the EW-7197 group than in the TGF-β fibrosis group. TGF-β decreased the expression of the epithelial marker KRT-8, an effect that was reversed by EW-7197 and SB431542. In the TGF-β-induced fibrosis model, the length of the thick vessels was reduced, and the diameter of both thick and thin vessels was decreased, but EW-7197 reversed these effects. EW-7197 significantly reduced the messenger RNA expression of TGF-β and increased the levels of vascular endothelial growth factor receptor 2, interleukin (IL)-10, and IL-6. EW-7197 reduced the levels of secretory cytokines TGF-β1, TGF-β3, IL- 1β. In the cisplatin-induced renal fibrosis mouse model, EW-7197 reduced renal fibrosis by down-regulating TGF-β signaling. CONCLUSION: EW-7197 attenuated the TGF-β1-induced fibrotic cellular response in the 3D chip model and animal model. These findings indicate the potential effect of EW-7197 in attenuating renal fibrosis.