Anemoside B4 targets GSK-3β to restrain neutrophil activation and ameliorates psoriasis via PKM2/STAT3 pathway inactivation.

BACKGROUND: Psoriasis is a chronic inflammatory skin disease characterized by keratinocyte hyperproliferation and neutrophil infiltration. In this condition, the release of neutrophil extracellular traps (NETs) significantly amplifies the inflammatory response. While the natural saponin anemoside B4 (AB4) possesses a well-documented anti-inflammatory profile and therapeutic promise in other diseases, its efficacy in psoriasis remains unconfirmed, and the metabolic basis for its action is poorly understood. OBJECTIVE: To investigate whether AB4 alleviates psoriasis by targeting neutrophil metabolism via the GSK-3β/PKM2/STAT3 axis. METHODS: A psoriatic model was induced on the dorsal skin of mice with imiquimod (IMQ), followed by therapeutic intervention with AB4. Following this, treatment efficacy was evaluated by ELISA, HE staining, and immunohistochemistry. To investigate the anti-psoriatic mechanism of AB4, primary neutrophils were isolated from murine bone marrow and HL60 cells were differentiated into neutrophil-like cells (dHL60) using DMSO induction. Immunofluorescence, western blot, and flow cytometry analysis were used to investigate the effects of AB4 on neutrophil activation and NETs formation. Moreover, drug affinity responsive target stability (DARTS), and cellular thermal shift assay (CETSA) assays were employed to investigate the direct binding proteins of AB4. RESULTS: The therapeutic effect of AB4, evidenced by reduced skin erythema, thickness, neutrophil infiltration, MPO release, and ROS damage in mice. Underlying these effects, AB4 downregulated neutrophil activation, infiltration, and NETs, exhibiting similar effects in primary neutrophils, neutrophil-like cells in vitro, and imiquimod-induced psoriasic inflammation skin of mice. Moreover, these effects of AB4 were achieved by inhibiting PKM2 phosphorylation and suppressing PKM2 dimer formation, thereby reprogramming neutrophil metabolism, subsequently inhibiting STAT3 phosphorylation, and ultimately suppressing epithelial cell proliferation. Finally, we explored the direct target mediating these effects of AB4, and demonstrated that AB4 could directly bind to GSK-3β, inhibiting its activity, subsequently suppressing the PKM2/STAT3 axis. CONCLUSIONS: AB4 is a promising anti-psoriatic agent that reprograms neutrophil metabolism via PKM2 tetramerization, suppressing STAT3 signaling and neutrophil infiltration at the metabolic-inflammatory crossroads. These findings identify AB4 as a promising candidate for therapeutic development.