Loganin ameliorates acetaminophen-induced acute liver injury via targeting TOP1MT-mediated hepatocyte apoptosis and ferroptosis

Acetaminophen (APAP) overdose can cause severe liver injury, and new drugs are urgent needed for effective treatment. Small molecules in Chinese medicine have long been a treasured reservoir for drugs screening. Here, we reported that loganin (LOG), an active ingredient in Corni Fructus, exerts hepatoprotective effects as indicated by potently alleviated liver damages in APAP-induced liver injury (AILI) murine model. LOG reversed the decreased SOD, GSH and CAT levels, and reduced lipid peroxidation, ROS production, and iron overload and hence reduced apoptosis/ferroptosis of hepatocytes of AILI models, as apoptosis/ferroptosis inducers abolished, whereas their inhibitors enhanced the effect of LOG. Through the activity-based proteome profiling (ABPP) clickable alkyne-tagged LOG probe, mitochondrial topoisomerase I (TOP1MT) was captured as a direct target of LOG, which was further validated by CETSA and ITC assays. Deficiency of TOP1MT significantly compromised the effects of LOG on H2O2-induced oxidative stress cell model via regulating downstream apoptosis/ferroptosis regulators Bax, Bcl-2, NRF2, GSH, SLC7A11, and GPX4. Consistently, LOG effect was greatly eliminated in AILI mice once the endogenous hepatic TOP1MT was knocked-down by AAV-TOP1MT shRNA. Thus, TOP1MT might be a potential target for AILI treatment and LOG represents one of the most promising candidate drugs or lead compounds.