Paeoniflorin attenuates hepatic ischemia-reperfusion injury by modulating Tmem176b⁺ macrophages polarization

Hepatic ischemia-reperfusion (I/R) injury, a major complication in liver transplantation and extensive resection, involves complex mechanisms with limited therapeutic options. The M1 polarization of macrophages has been confirmed as one of the contributing factors to hepatic I/R injury. Paeoniflorin (PF), a bioactive compound from traditional Chinese medicine, exhibits hepatoprotective and immunomodulatory properties, its precise mechanism in regulating macrophage polarization during hepatic I/R remains unclear.

Single-cell RNA sequencing was performed on 45,673 cells isolated from the PF-treated hepatic I/R mouse model liver. Bioinformatics analysis was employed to assess the functional characteristics, phenotypic switching, and cell-cell interaction of different macrophage subpopulations. TMEM176B inhibitor and mice hepatic I/R model were utilized to validate Tmem176b⁺ macrophages as PF' s therapeutic target.

PF administration markedly improved hepatic function, evidenced by reduced serum ALT/AST levels, diminished necrotic area and suppressed apoptosis. Single-cell RNA sequencing revealed PF' s preferential modulation of macrophage subpopulations, inducing a significant shift from M1-like to M2-like phenotypes. Pseudotime trajectory analysis demonstrated PF-facilitated conversion of inflammatory macrophages toward this reparative subset. Functional studies demonstrated that Tmem176b⁺ macrophages are essential, as their depletion could abolish the protective effect of PF. Mechanistically, PF mediates its effects through Tmem176b⁺ macrophage by upregulating the THBS1-CD47 immunosuppressive axis while suppressing the SPP1-CD44 pro-inflammatory signaling pathway.

These findings demonstrate that PF attenuates hepatic I/R injury by upregulating Tmem176b⁺ macrophages, which are essential for its protective effects. Our study provides comprehensive mechanistic insights into PF-mediated hepatoprotection and supports its potential clinical application in hepatic I/R therapy.