Schisandrin B promotes senescence of activated hepatic stellate cell via NCOA4-mediated ferritinophagy

Context Schisandrin B (Sch B), an active ingredient from Schisandrae chinensis (Turcz.) Baill. (Schisandraceae) Fructus, possesses diverse pharmacological activities including antitumor, anti-inflammation, and hepatoprotection. Objective To explore the effect of Sch B on activated HSCs senescence in hepatic fibrosis and the mechanisms implicated. Materials and methods ICR mice with CCl4-induced hepatic fibrosis were supplemented with Sch B (40 mg/kg) for 30 d and LX2 cells were treated with Sch B (5, 10 and 20 mu M) for 24 h. Cellular senescence was assessed by senescence-related indicators senescence-associated beta-galactosidase (SA-beta-gal) activity and the expression of p16, p21, p53, gamma-H2AX, H3K9me3, TERT, TRF1, and TRF2. Ferric ammonium citrate (FAC) and NCOA4 siRNA were used to evaluate the mechanisms underlying Sch B's regulation of cellular senescence. Results Sch B (40 mg/kg) reduced serum levels of AST and ALT (53.2% and 63.6%), alleviated hepatic collagen deposition, and promoted activated HSCs senescence in mice. Treatment with Sch B (20 mu M) decreased cell viability to 80.38 +/- 4.87% and elevated SA-beta-gal activity, with the levels of p16, p21 and p53 increased by 4.5-, 2.9-, and 3.5-fold and the levels of TERT, TRF1 and TRF2 decreased by 2.4-, 2.7-, and 2.6-fold in LX2 cells. FAC (400 mu M) enhanced Sch B's effect mentioned above. NCOA4 siRNA weakened the effects of Sch B on iron deposition and HSCs senescence. Conclusions Sch B could ameliorate hepatic fibrosis through the promotion of activated HSCs senescence, which might be attributed to its induction of NCOA4-mediated ferritinophagy and subsequent iron overload.