Objective To investigate the effects and related mechanisms of mitochondrial-derived peptide MOTS-c on glycochenodeoxycholic acid (GCDCA)-induced injury in human hepatocytes (THLE-3 cells).

Methods THLE-3 cells were cultured in vitro and treated with different concentrations of GCDCA and MOTS-c. The optimal concentrations of GCDCA and MOTS-c were determined by CCK-8 method. Subsequently, THLE-3 cells were treated or pre-treated with GCDCA (200 µmol/L), MOTS-c (15, 30, 60 µmol/L), the multidrug resistance protein 2 (MRP2) inhibitor Probenecid (500 µmol/L), and the nuclear factor erythroid 2-related factor 2 (Nrf2) inhibitor ML385 (10 µmol/L). Cell proliferation was assessed by CCK-8 method. Lactate dehydrogenase (LDH) levels in the culture medium were measured by biochemical method. Cell apoptosis rates were determined by flow cytometry. MRP2 messenger RNA (mRNA) levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR). MRP2 and Nrf2 protein expression levels were analyzed by Western blotting.

Results As the concentration of GCDCA increased, the proliferation activity of THLE-3 cells gradually decreased, while LDH activity in the culture medium and apoptosis levels increased, and the expression levels of MRP2 in the cells decreased (all P<0.05). Treatment with 30 and 60 µmol/L MOTS-c significantly enhanced the proliferation activity of THLE-3 cells exposed to GCDCA, upregulated the expression of MRP2 and Nrf2, and reduced LDH activity and apoptosis levels (all P<0.05). Co-treatment with Probenecid partially reversed the protective effects of MOTS-c on GCDCA-induced THLE-3 cell injury, while co-treatment with ML385 partially inhibited the induction of MRP2 expression by MOTS-c in THLE-3 cells exposed to GCDCA.

Conclusions MOTS-c may alleviate GCDCA-induced injury in human hepatocytes (THLE-3 cells), and its mechanism may be related to the upregulation of MRP2 expression mediated by Nrf2.