Protective Effect of Mesaconate on Autoimmune Hepatitis via Suppression of Inflammatory Response and Oxidative Stress

Autoimmune hepatitis (AIH) is a severe immune-mediated liver disease with limited treatment options beyond immunosuppressants, which carry significant side effects. Existing evidence suggests that mesaconate (MSA) possesses immunomodulatory properties and may offer advantages over itaconate derivatives by avoiding succinate dehydrogenase inhibition. However, its specific role in AIH remains unclear. This study aimed to investigate the therapeutic effects of MSA on AIH and to elucidate its underlying mechanisms of action.

A murine AIH model was established via tail vein injection of concanavalin A (ConA, 20 mg/kg). MSA (250 mg/kg) was administered intraperitoneally 6 h before ConA exposure. Liver histology, serum transaminase levels, apoptosis markers, oxidative stress markers, and inflammatory cytokines were analyzed to assess the therapeutic efficacy of MSA. Additionally, RNA sequencing and Western blotting were performed to explore the mechanisms of MSA action. In vitro validation was conducted using RAW264.7 macrophages pretreated with MSA (1 mM) followed by interferon-gamma (IFN-γ, 50 ng/mL) stimulation.

MSA pretreatment effectively mitigated ConA-induced AIH by reducing inflammatory responses, oxidative stress, and apoptosis both in vivo and in vitro. The underlying protective mechanism involved MSA-mediated downregulation of IFN-γ expression and subsequent inhibition of the Janus tyrosine kinase 1/2-signal transducer and activator of transcription 1 signaling pathway. The involvement of this pathway in human AIH was also confirmed.

This study provides the first evidence that MSA ameliorates AIH by suppressing the IFN-γ-Janus tyrosine kinase 1/2-signal transducer and activator of transcription 1 signaling pathway, offering novel mechanistic insights and a promising therapeutic candidate for the future treatment of autoimmune disorders.