Forsythoside E Alleviates Liver Injury by Targeting PKM2 Tetramerization to Promote Macrophage M2 Polarization.

Sepsis-induced liver injury is closely associated with poor prognosis  in septic patients. In this study, through integrated approaches including high-throughput virtual screening, target fishing technology, and atomic force microscopy (AFM) analysis, Forsythiaside E (FE) is first identified as a novel allosteric activator of pyruvate kinase M2 (PKM2) that promotes tetramer formation. Mutant protein construction combined with dynamic light scattering (DLS) and fluorescence resonance energy transfer (FRET) reveals FE binds to PKM2 K311 to promote tetramer formation. Employing Seahorse XF metabolic analyzers, real-time single-cell multi-modal analysis systems, and transcriptome sequencing, it is revealed that FE-mediated PKM2 tetramerization induces metabolic reprogramming in macrophages while suppressing STAT3 phosphorylation and subsequent NLRP3 transcriptional activation. In vivo assessments indicate that FE exhibited no significant multi-organ toxicity. FE alleviates sepsis-induced liver injury by promoting macrophage polarization toward the M2 anti-inflammatory phenotype. Further validation through macrophage-specific overexpression of PKM2 WT/K311A in mice confirms FE's mechanism of action. Collectively, this study elucidates the molecular mechanism by which FE alleviates sepsis-associated liver injury through targeted PKM2 tetramerization and proposes an innovative metabolic-epigenetic coordinated regulation strategy for sepsis-related liver injury treatment.