Baicalin attenuates acetaminophen-induced acute liver injury through inhibiting TLR2-dependent neutrophil extracellular trap formation

Excessive use of acetaminophen can induce acute liver injury, characterized by rapid neutrophil infiltration and hepatocellular necrosis, which is associated with high mortality rates worldwide. Elucidating the underlying mechanisms and identifying potential therapeutic agents are therefore crucial for improving the understanding and treatment of this pathology. Baicalin is widely used in the treatment of liver diseases, including acute liver injury, yet the underlying mechanisms remain incompletely understood. In this study, we first demonstrated that baicalin could alleviate APAP-induced liver injury. The infiltration of neutrophils and neutrophil extracellular traps (NETs) formation are key events during liver injury. We found that both DNase I and baicalin efficiently inhibit NETs formation, while the combination of DNase I and baicalin did not further ameliorate liver injury, suggesting that baicalin exerts its pharmacological functions mainly through NETs inhibition. In addition, we showed that APAP can directly induce NETs formation in vitro, an effect that was reversed by baicalin. This process is mediated mainly through TLR2-dependent NETosis, since TLR2 inhibitor suppressed APAP-induced NETs formation. Additional investigations revealed that baicalin inhibits the transcription of Nlrp3 and Caspase1, thereby suppressing the maturation of gasdermin D (GSDMD). These results indicate that baicalin inhibits NETs formation possibly via TLR2/NLRP3/Caspase-1/GSDMD signaling pathway. In conclusion, our study identifies baicalin as a potent inhibitor of NETosis that effectively attenuates APAP-induced NETs formation and may have therapeutic potential for APAP-induced acute liver injury and other NETosis-related diseases.