Nintedanib inhibits TGF-β-induced myofibroblast transdifferentiation in human Tenon's fibroblasts

This study aimed to investigate the effect of nintedanib on the conversion of human Tenon's fibroblasts (HTFs) into myofibroblasts and reveal the molecular mechanisms involved.

Primary cultured HTFs were incubated with transforming growth factor β1 (TGF-β1) alone or combined with nintedanib, and cell proliferation and migration were measured by cell counting kit-8 (CCK8) and the scratch wound assay, respectively. HTF contractility was evaluated with a 3D collagen contraction assay. The mRNA and protein levels of α smooth muscle actin (α-SMA) and Snail and the phosphorylation levels of Smad2/3, p38 mitogen-activated protein kinase (p38MAPK), and extracellular signal-regulated kinase ½ (ERK1/2) were determined by quantitative reverse transcription polymerase chain reaction (RT-PCR), western blot, and immunofluorescence staining.

Nintedanib inhibited the proliferation and migration of HTFs in a dose-dependent manner. Furthermore, nintedanib prevented HTF myofibroblast differentiation via downregulation of mRNA and protein expression of α-SMA and Snail. A three-dimensional (3D) collagen gel contraction assay demonstrated that nintedanib effectively inhibits myofibroblast contraction induced by TGF-β1. Mechanistically, we revealed that nintedanib reduces the TGF-β1-induced phosphorylation of Smad2/3, p38MAPK, and ERK1/2, suggesting that nintedanib acts through both classic and nonclassic signaling pathways of TGF-β1 to prevent HTF activation.

Our study provides new evidence that nintedanib has potent antifibrotic effects in HTFs and suggests that it may be used as a potential therapeutic agent for subconjunctival fibrosis.