Forsythiaside A ameliorates acetaminophen-induced liver injury by suppressing ferroptosis through activating USP11/SIRT3-mediated mitophagy.

ETHNOPHARMACOLOGICAL RELEVANCE: Acetaminophen (APAP), a widely used antipyretic and analgesic, frequently causes liver injury upon overdose. The fruit of Forsythia suspensa (Thunb.) Vahl, known as Forsythiae Fructus, is a traditional Chinese medicine used to clear heat and toxic, remove lumps, and reduce swelling. Forsythiaside A (FTA), an important active ingredient in Forsythiae Fructus, has significant antioxidant, anti-inflammatory and hepatoprotective effects. However, its protective mechanisms against acetaminophen-induced liver injury (AILI) remain unclear.

AIM OF THE STUDY: This study aimed to investigate the protective role and underlying molecular mechanisms of FTA in AILI.

METHODS

The AILI model was established to evaluate the hepatoprotective effects of FTA. H&E staining was used to observe histopathology, while serum transaminase activities and hepatic biochemical parameters were assessed using commercial assay kits. To understand the mechanisms, in vivo studies included immunohistochemistry, immunofluorescence, Western blot, and real-time quantitative polymerase chain reaction (RT-qPCR). In vitro analyses further evaluated the efficacy and mechanistic actions through MTT, Western blot, RT-qPCR, immunofluorescence, co-immunoprecipitation, molecular docking, and cell transfection assays.

RESULTS

FTA alleviated liver histopathological damage and reduced serum transaminases. FTA decreased malondialdehyde (MDA) and Fe2+ levels, restored glutathione (GSH), and up-regulated key ferroptosis suppressors at both protein and mRNA levels. Moreover, FTA promoted the colocalization of the autophagy marker microtubule-associated protein light chain 3B (LC3B) with mitochondria, while increasing the expression of ubiquitin-specific peptidase 11 (USP11) and sirtuin 3 (SIRT3). Importantly, USP11 silence by siRNA reversed FTA-mediated mitigation of mitophagy and ferroptosis.

CONCLUSION

FTA ameliorates AILI by suppressing ferroptosis through activating USP11/SIRT3-mediated mitophagy, revealing a novel mechanistic pathway.