SILAC-based proteomic profiling of the suppression of TGF-ß1-induced lung fibroblast-to-myofibroblast differentiation by trehalose.

Fibroblast-to-myofibroblast differentiation is one of the most important characteristics of pulmonary fibrosis, and screening natural compounds targeting fibroblast differentiation is always a promising approach to discover drug candidates for treatment of pulmonary fibrosis. Trehalose reportedly has many potential medical applications, especially in treating neurodegeneration diseases. However, it remains unclear whether trehalose suppresses lung fibroblast differentiation. In this work, we found that trehalose decreased the expression levels of α-smooth muscle actin (α-SMA) following the induction of transforming growth factor ß1 (TGF-ß1) in pretreatment, co-treatment, and post-treatment groups. Trehalose also reduced the production of type I collagen, lung fibroblast-containing gel contractility and cell filament formation in TGF-ß1-stimulated MRC-5 cells. Although trehalose is a known autophagy inducer, our results showed that its suppressive effect on fibroblast differentiation was not via trehalose-induced autophagy. And it did not affect canonical TGFß/Smad2/3 pathway. By applying proteomic profiling technology, we demonstrated that the downregulation of ß-catenin was involved in the trehalose-repressive action on fibroblast differentiation. The ß-catenin agonist, SKL2001, reversed the suppressive effect of trehalose on fibroblast differentiation. Overall, these experiments demonstrated that trehalose suppressed fibroblast differentiation via the downregulation of ß-catenin, but not through canonical autophagy and TGFß/Smad2/3 pathway, which is not only a novel understanding of trehalose, but also quite helpful for in vivo research of trehalose on pulmonary fibrosis in future.

Baicalein represses TGF-ß1-induced fibroblast differentiation through the inhibition of miR-21.

Fibroblast-to-myofibroblast differentiation is a highly important pathological characteristic of pulmonary fibrosis. In this study, we aimed to investigate the effects and mechanisms of baicalein on the differentiation of human lung fibroblasts. Baicalein reduced the levels of α-smooth muscle actin (α-SMA) mRNA and protein expression in TGF-ß1-treated human lung fibroblasts. It also decreased the contents of collagen type I and fibronectin in time- and dose-dependent manners, and retarded TGF-ß1-stimulated α-SMA filament formation. Baicalein diminished the expression of miR-21, and miR-21 mimics partially antagonized the effects of baicalein. Additionally, Baicalein inhibited the miR-21 transcriptor STAT3 activity but not AP-1 activity. Moreover, the expression of Spry 1 protein, a miR-21 known target, was improved by baicalein treatment, but the level of Smurf2 protein, another miR-21 target, was not interfered. Collectively, these results demonstrated that baicalein can attenuate TGF-ß1-induced human lung fibroblast differentiation by inhibiting the miR-21 expression.