Protocatechualdehyde protects against acute liver injury by inhibiting RIPK1-mediated necroptosis and IFN-γ/JAK1/STAT1 axis.

Acute liver injury (ALI) is characterized by massive hepatocyte necrosis and rapid deterioration of liver function, which is closely associated with a cytokine storm mediated by the excessive activation of macrophages. Currently, there is a lack of effective targeted drugs in clinical practice. This study aimed to investigate the protective effects and mechanisms of protocatechualdehyde (PCA) against ALI. PCA exerts its biological effects by inhibiting macrophage-driven inflammation. The protective effects and mechanisms of PCA were experimentally validated using both in vivo and in vitro assays. In vivo, mice with ALI induced by lipopolysaccharide (LPS), acetaminophen (APAP), or carbon tetrachloride (CCl₄) showed reduced liver tissue damage, decreased serum transaminase levels, and downregulated inflammatory cytokine levels after PCA treatment, indicating that PCA protects against ALI induced by multiple causes. In vitro experiments further demonstrated that, within a safe concentration range, PCA significantly inhibit the expression of inflammatory cytokines in LPS-induced RAW264.7 cells and suppress necroptosis. Mechanistically, PCA functions through multiple pathways. It directly binds to RIPK1 to inhibit necroptosis in macrophages. Furthermore, it downregulates IFN-γ, subsequently blocking the JAK1/STAT1 signaling pathway and reducing the release of IL-17a and Ccl20. A reduction in these cytokines diminishes the infiltration of neutrophils and T cells, thereby improving the inflammatory milieu in ALI. In conclusion, PCA synergistically attenuates macrophage-driven inflammatory injury by inhibiting RIPK1-mediated necroptosis and regulating the IFN-γ/JAK1/STAT1 signaling axis, providing experimental evidence of its potential as a therapeutic agent for ALI.