Sinensetin protects against pulmonary fibrosis via inhibiting Wnt/β-Catenin signaling pathway

Pulmonary fibrosis is a fatal lung disease characterized by progressive fibroblast proliferation and extensive extracellular matrix (ECM) deposition. Although great efforts have been placed to understand the pathogenesis and explore therapeutic strategies, the treatment options for pulmonary fibrosis are very limited and the prognosis of pulmonary fibrosis patients remains poor. Sinensetin is a polymethoxylated flavone derived from citrus fruits, and has been characterized with anti-fibrotic property. However, the underlying mechanism is still unclear. In present study, combining in vitro and in vivo models, we revealed for the first time that sinensetin can protect against pulmonary fibrosis via inhibiting glycogen synthase kinase-3β (GSK-3β)-mediated Wnt/β-Catenin signaling pathway. According to our results, the activation of Wnt/β-Catenin signaling pathway in pulmonary fibrosis is responsible for fibroblast proliferation and differentiation to form ECM-producing myofibroblasts. Sinensetin treatment dephosphorylates and activates GSK-3β, a component of β-Catenin destruction complex, which induces β-Catenin degradation and deactivates Wnt/β-Catenin-mediated fibroblast proliferation and differentiation. As a result, myofibroblasts formation and ECM production are reduced and the progression of pulmonary fibrosis is suppressed. These results not only advance our knowledge on the pharmacological activities of sinensetin, but also provide novel insights on pulmonary fibrosis treatment.