Saikosaponin D Exacerbates Acetaminophen-induced Liver Injury by Sabotaging GABARAP-SNARE Complex Assembly in Protective Autophagy
Background : Radix Bupleuri (RB) and acetaminophen (APAP) are two popular medications having potential hepatotoxicity and substantial risks of irrational co-administration and excessive use, posing an overlooked danger of drug-induced liver injury (DILI). Autophagy is a protective mechanism against APAP-induced DILI, yet, saikosaponin d (SSd) in RB has been characterized to regulate autophagy, although the current findings are controversial. Purpose : We aim to elucidate whether SSd promoted APAP-induced liver injury by regulating autophagy. Methods : UPLC-MS analysis was employed to measure the hepatic abundance of APAP-cysteine protein adducts. Multiple techniques such as fluorescence probe, proteinase K protection assay, immunoprecipitation-coupled proteomic analysis, surface plasmon resonance, molecular docking and et.al were applied to evaluate the SSd on autophagy flux. Results : We discovered that, by inhibiting autophagy, SSd impaired the removal of APAP-cysteine protein adducts and delayed the compensation of damaged mitochondria. This ultimately potentiated the development of severe liver toxicity induced by subtoxic APAP. The use of autophagy probes, transmission electron microscopy, membrane curative assay, and protein K assay collectively revealed that SSd predominately disrupted autophagosome-lysosome fusion, without affecting other stages of autophagic flux. Immunoprecipitation-coupled proteomic analysis and surface plasmon resonance further found that SSd directly bound to GABARAP, thus preventing the recruitment and autoactivation of STX17 and the following assembly of STX17-SNAP29-VAMP8 complex. Conclusion : In conclusion, our findings not only highlight the significant risk of drug-induced liver injury associated with the co-administration of RB and APAP in clinical practice but also unveils that GABARAP-SNARE complex is a novel druggable target for the treatment of autophagy-related diseases.
危险品化学品经营许可证（带存储）