BMSCs attenuate hepatic fibrosis in autoimmune hepatitis through regulation of LMO7-AP1-TGFβ signaling pathway

Objective In a previous study, we reported that transplantation of bone mesenchymal stem cells (BMSCs) significantly attenuated liver damage in a mouse autoimmune hepatitis (AIH) model. Moreover, expression of the LIM domain protein, LMO7, correlated positively with the invasive capacity of hepatoma cells. However, whether LMO7 plays a role in inflammation and fibrosis of AIH remains unknown. This investigation aimed to explore the effect of BMSC transplantation on LMO7 and the role of LMO7 in hepatic fibrosis. Materials and methods S100-induced murine AIH and LPS-induced hepatocyte injury models were successfully established. Three doses of BMSCs were injected into AIH mice via the tail vein. LPS-treated AML12 cells were co-cultured with BMSCs in vitro. Small interfering (si) LMO7 RNA and T5224 (a specific inhibitor of AP-1) were used to demonstrate the relationship between LMO7-AP1-transforming growth factor (TGF)-β. Results Pathological examination and serum alanine and aspartate aminotransferase levels indicated that liver damage was notably ameliorated in the BMSC-treated mice. LMO7 level was upregulated, while AP-1 and TGF-β levels were downregulated upon intervention with BMSCs. AP-1 expression was upregulated in the siLMO7 group, whereas TGF-β level was downregulated in the T5224 group when compared to those in the control group. Conclusions BMSC transplantation significantly limits liver fibrosis and upregulates the expression of LMO7. LMO7 inhibits the TGF-β pathway by inhibiting AP-1. This implies that BMSCs are a potential means of treating liver fibrosis. This approach has important implications for the treatment of AIH and other fibrotic diseases.