Mesenchymal stem cell-derived extracellular vesicles attenuate liver transplantation-induced ischemia/reperfusion injury by suppressing hepatocellular complement C5 expression.

BACKGROUND & AIMS: Hepatic ischemia-reperfusion injury (HIRI) is an unavoidable complication of liver transplantation (LT) that drives allograft dysfunction and mortality. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) show therapeutic promise, yet their actions within the hepatic network remain incompletely defined. We investigated how MSC-EVs protect against LT-induced HIRI, focusing on intercellular communication and complement-mediated inflammation.

METHODS

Single-cell RNA sequencing, single-nucleus ATAC-seq, and spatial transcriptomics were performed in rat LT and mouse HIRI livers with or without MSC-EV treatment. Cell migration assays, AAV-mediated overexpression, and PTPN13-knockdown MSC-EVs were used to prove cellular function and mechanisms.

RESULTS

MSC-EVs attenuated HIRI, improving liver function and reducing histologic injury and hepatocyte apoptosis. Single-cell analyses showed selective curtailment of mononuclear phagocyte and neutrophil recruitment to injured liver. Mechanistically, HIRI induced hepatocyte C5 and C5a, which engaged C5aR1 on mononuclear phagocytes and neutrophils to drive chemotaxis. Consistent with this pathway, MSC-EVs delivered PTPN13 to hepatocytes, lowering C5 and promoting ERK1/2 dephosphorylation and enhanced C/EBPα activity. Elevated C/EBPα activity directly suppressed C5 transcription, whereas PTPN13-depleted MSC-EVs showed diminished efficacy.

CONCLUSIONS

We present a single-cell multi-omics atlas of MSC-EV therapy across rat LT and mouse HIRI, supported by clinical data. MSC-EVs mitigated HIRI by lowering hepatocyte C5 and reducing mononuclear phagocyte and neutrophil recruitment. MSC-EV delivery of PTPN13 dephosphorylated ERK1/2 and enhanced C/EBPα, repressing hepatocyte C5 and dampening C5a-C5aR1 signaling. These findings position MSC-EVs as a translational nanotherapy to improve graft outcomes after LT.