Forsythiaside A suppresses PANoptosis to alleviate senecionine-induced hepatotoxicity

Senecio scandens Buch.-Ham. ex D.Don (Qianliguang) is widely used in China, but its clinical application is limited due to the presence of pyrrolizidine alkaloids (PAs), which are well-known natural hepatotoxins. Forsythia suspensa (Thunb.) Vahl (Lianqiao), traditionally applied for heat-clearing and detoxification, is often combined with S. scandens in clinical practice. According to the detoxification theory of traditional Chinese herbal compatibility, F. suspensa may alleviate PA-induced hepatotoxicity.

To identify bioactive compounds from compatible herbal medicines that mitigate hepatotoxicity induced by senecionine (SEN), which is a representative PA in S. scandens, and to investigate the protective effect and mechanisms of Forsythiaside A (FTA), which is a major active compound from F. suspensa.

Sixty-six compounds from compatible herbal medicines were screened for their ability to alleviate SEN-induced cytotoxicity in mouse primary hepatocytes. The detoxifying effects of FTA were further verified in SEN-intoxicated mice. Serum biochemical analysis and histopathological evaluation were performed to assess the hepatoprotective effects of FTA. Transcriptomic analysis, quantitative real-time polymerase chain reaction (qRT-PCR), and western blotting were conducted to investigate the underlying molecular mechanisms.

Sixteen compounds significantly reversed SEN-induced cytotoxicity in hepatocytes, with FTA showing the most potent effect. FTA reduced serum alanine/aspartate aminotransferase (ALT/AST) activities, mitigated hepatocellular injury, and suppressed hepatic inflammation in mice intoxicated with SEN. Furthermore, in vivo results revealed that SEN induced marked PANoptosis in hepatic parenchymal cells in mouse. Interestingly, in vitro experiments showed that PANoptosis in mouse primary hepatocytes was triggered by co-stimulation with interferon γ (IFN-γ) and tumor necrosis factor α (TNF-α), rather than SEN alone. FTA inhibited PANoptosis in SEN-intoxicated mouse livers and in hepatocytes co-stimulated with IFN-γ plus TNF-α.

PANoptosis is essentially involved in SEN-induced liver injury. FTA alleviates SEN-induced hepatotoxicity by inhibiting PANoptosis, supporting the traditional detoxification theory of herbal compatibility.