Annexin A5 ameliorates immune-mediated liver injury by regulating ferritinophagy-ferroptosis in M2 macrophages via the NRF2/ERK pathway.

BACKGROUND & AIM: M2 macrophages are key drivers of immune-mediated liver injury. The aim of this study was to investigate the mechanisms by which Annexin A5 regulates ferroptosis in M2 macrophages and its protective effect against immune liver injury.

METHODS

The colocalization of ferroptosis in M2 macrophages from autoimmune hepatitis (AIH) patients and mice with ConA-induced immune liver injury was analyzed via laser confocal microscopy. The effects of ferritinophagy and autophagosomal-lysosomal fusion on the regulation of ferroptosis in M2 macrophages by Annexin A5 were investigated through mCherryGFP-LC3B adenovirus transfection. Ferroptosis of M2 macrophages was studied by using si-RNA and chemical inhibitors and agonist of nuclear factor erythroid 2-related factor 2 (NRF2) and extracellular signal-regulated kinase (ERK). Bone marrow-derived macrophages were polarized into M2 macrophages for use in cell transfer experiments. A coculture model of M2 macrophages and hepatocytes was established to study the effect of M2 macrophages on liver regeneration.

RESULTS

M2 macrophages are highly sensitive to ferroptosis in immune-mediated liver injury, and Annexin A5 can effectively inhibit ferroptosis in M2 macrophages, thereby exerting a protective effect on immune-mediated liver injury. Annexin A5 alleviates ferritinophagy by inhibiting the degradation of NRF2 and the phosphorylation of ERK1/2, as well as by inhibiting autophagosome-lysosome fusion. This enhances the resistance of M2 macrophages to ferroptosis and improves outcomes in immune-related liver injury. Additionally, the inhibition of ferroptosis in M2 macrophages promotes hepatocyte regeneration.

CONCLUSION

Our findings comprehensively reveal that the modulation of the NRF2-ERK1/2 signaling pathway by Annexin A5 is essential for mitigating ferroptosis in M2 macrophages during immune-mediated liver injury. Therefore, targeting Annexin A5 may offer novel therapeutic approaches for the treatment of immune-mediated liver injury.