Fig 2: FST overexpression decreased lipid accumulation in FFA-treated LO2 cells. (A and B) The efficiency of FST overexpression in LO2 cells was demonstrated by RT-qPCR and Western blotting. (C and D) Oil red O staining and analysis result of control cells (EGFP) and FST-overexpressing LO2 cells treated with 1.0 mM FFA for 24 h (400×, scale bar=50 µm). (E–G) The protein levels and analysis results of ACC1, FASN, SREBP1, ChREBP, Akt, Akt-Thr308, Akt-Ser473, p-mTOR, and mTOR in the control cells and FST-overexpressing LO2 cells treated with 1 mM FFA for 24h. β-actin was used as a loading control.

Fig 3: Hepatic FST level was elevated in NAFLD liver samples compared to normal liver samples. (A) H&E staining of liver sections in NAFLD and normal liver samples (200×, scale bar: 100 µm). (B and C) Immunohistochemical staining and analysis result of hepatic FST in NAFLD and normal liver samples (400×, scale bar: 50 µm). (D) Immunofluorescence staining of hepatic FST in NAFLD and normal liver samples. (630×, scale bar: 20 µm). (E and F) The protein level and analysis result of hepatic FST in NAFLD and normal liver samples. ß-actin was used as a loading control.

Fig 4: Hepatic FST expression increased in HFD mice. (A and B) The hepatic protein levels and analysis results of FST, ACC1, FASN, SREBP1, and ChREBP in NCD and HFD mice. ß-actin was used as a loading control. (C) Immunohistochemical staining of hepatic FST in NCD and HFD mice (400×, scale bar= 50 µm).

Fig 5: Overexpression of FST reduces cardiac fibrosis by inhibiting the activation of the TGF-ß–Smad3 pathway in vivo and in vitro. Quantitative real-time PCR analysis of TGF-ß1, activin A, and TGF-ß3 mRNA transcription [(A–C), n=4] and p-Smad3 and Smad3 protein expression in each group [(D), n = 4]. In vitro, NIH3T3 cells were treated with or without high glucose (30 mM), recombinant FST protein (10 ng/ml), and TGF-ß1 (20 µM). Protein expression of COL1, COL3, p-Smad3, and Smad3 with different treatments [(E–G), n = 3]. *p< 0.05; **p< 0.01; ***p<0.001.