Xanthohumol Inhibits TGF-β1-Induced Cardiac Fibroblasts Activation via Mediating PTEN/Akt/mTOR Signaling Pathway

Background: Xanthohumol (Xn) is the most abundant prenylated flavonoid in Hops (Humulus lupulus L.), and exhibits a range of pharmacological activities. This study aimed to investigate the effect of Xn on TGF-beta 1 -induced cardiac fibroblasts activation and elucidate the underlying mechanism. Materials and Methods: The cellTiter 96 (R) AQueous one solution cell proliferation assay kit was adopted to determine the cell viability of cardiac fibroblasts, and the proliferation was detected through 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay. The alpha-SMA protein expression was measured by using immunofluorescence and Western blotting. Western blotting was conducted to test the protein expressions of collagen I and III, PTEN, p-Akt, Akt, p-mTOR, mTOR, p-Smad3, Smad3 and GAPDH. The mRNA levels of alpha-SMA, collagen I and III were determined by quantitative real-time polymerase chain reaction (PCR). Results: Xn inhibited the TGF-beta-induced proliferation, differentiation and collagen overproduction of cardiac fibroblasts. TGF-beta 1 induced the down-regulated PTEN expression, Akt and mTOR phosphorylation. These effects of TGF-beta 1 were suppressed by Xn, while blocking of PTEN reduced Xn-mediated inhibitory effect on cardiac fibroblasts activation induced by TGF-beta 1. Conclusion: Xn inhibits TGF-beta 1-induced cardiac fibroblasts activation via mediating PTEN/Akt/mTOR signaling pathway.