Lower L-glutamine abundance and higher HSPA8 activity contribute to the mitigation of ethanol-induced liver cell injury by thymol.

Ethanol metabolism activates the generation of reward value by neurons, but it results in liver injury. The underlying processes through which thymol mitigates liver injury caused by ethanol exposure remain incompletely understood. In the present study, thymol alleviated ethanol-induced a decrease in superoxide dismutase activity. Thymol attenuated ethanol-induced elevation of lipid accumulation, as evidenced by a lesser number of larger lipid droplets and lower lipid synthesis. Correspondingly, thymol was found to counteract ethanol-induced downregulation in the ratio of phospho-AMPKα to total AMPKα. Altered metabolites in cells treated with ethanol plus thymol were notably enriched in purine metabolism, citric acid cycle, mitochondrial electron transport chain, and glycerol phosphate shuffle. Thymol inhibited ethanol-induced elevation in L-glutamine abundance. Further investigations revealed that supplementation with L-glutamine intensified the damage induced by ethanol. This exacerbation was manifested through increased levels of total cholesterol and triglyceride, a greater number of larger lipid droplets, and reduced superoxide dismutase activity. Moreover, we found that the improving effect of thymol on ethanol-induced autophagic flux obstruction was mediated by higher abundances of glycosylated LAMP1 and ATP6V1B2 proteins. Finally, VER-155008, an inhibitor of heat shock protein 8, abolished the effects of thymol on ethanol-induced increases in the abundances of Il6 mRNA, Tnf mRNA, Tgfb1 mRNA, malondialdehyde, Fasn mRNA, Srebf1 mRNA, and Xdh mRNA, the LC3-II/LC3-I ratio, and SQSTM1 protein. VER-155008 also blocked the effect of thymol on ethanol-induced a reduction in glycosylated LAMP1 protein expression. These data provide novel insights into the impact of thymol on ethanol-induced liver injury.