Human umbilical cord mesenchymal stem cells ameliorate liver fibrosis by inhibiting hepatocyte ferroptosis and macrophage polarization via the miR-455-3p/PLAU axis.

BACKGROUND

Peripheral infusion of human umbilical cord mesenchymal stem cells (hUC-MSCs) may therapeutically treat liver fibrosis. hUC-MSCs can influence liver fibrosis progression and immune microenvironment remodeling via microRNAs (miRNAs).

METHODS

Bioinformatics showed the miR-455-3p/PLAU axis might regulate ferroptosis in liver fibrosis and affect the immune microenvironment. hUC-MSCs were transplanted into CCL4 induced liver-fibrotic male C57BL/6 mice. Liver tissues were stained (Hematoxylin and eosin (H&E), Masson, Sirius Red) to assess fibrosis; Alpha-smooth muscle actin (α-SMA) expression was detected by immunohistochemistry (IHC). Macrophage polarization was measured by immunofluorescence (IF), quantitative real-time polymerase chain reaction (qRT-PCR), and flow cytometry. Dual-luciferase and RNA pull-down assays verified miR-455-3p/PLAU regulation. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBIL) evaluated liver function. Reactive oxygen species (ROS), glutathione peroxidase 4 (GPX4), iron content, and ferrous iron (Fe) assessed ferroptosis. Enzyme-linked immunosorbent assay (ELISA) detected cytokines in supernatant.

RESULTS

In fibrotic vs. normal liver tissues, miR-455-3p was down-regulated, PLAU up-regulated, and ferroptosis increased. hUC-MSCs transplantation improves CCL4 induced liver fibrosis by inhibiting ferroptosis of hepatocytes through the miR-455-3p/PLAU axis. It also alleviated macrophage M1 polarization and liver damage.

CONCLUSION

hUC-MSCs inhibit hepatocyte ferroptosis via the miR-455-3p/PLAU axis, alleviate macrophage M1 polarization, and slow liver fibrosis. These findings offer insights for future liver fibrosis research and treatment.