Hepatic progenitor cells reprogrammed from mouse fibroblasts repopulate hepatocytes in Wilson’s disease mice

Wilson's disease (WD) is a genetic disorder that impairs the excretion of copper in hepatocytes and results in excessive copper deposition in multiple organs. The replacement of disordered hepatocytes with functional hepatocytes can serve as a lifelong therapeutic strategy for the treatment of WD. The aim of this study was to determine the hepatocyte repopulation effects of fibroblast-derived hepatic progenitor cells in the treatment of WD. Induced hepatic progenitor cells (iHPCs) were generated through direct reprogramming of adult mouse fibroblasts infected with lentivirus carrying both the Foxa3 and Hnf4α genes. These iHPCs were subsequently identified and transplanted into copper-overload WD mice with the Atp7b (H1071Q) mutation via caudal vein injection. After lentivirus infection, the fibroblasts transformed into Foxa3- and Hnf4α-overexpressing cobblestone-like cells with reduced expression of fibroblast markers and increased expression of epithelial cell and hepatic progenitor cell markers, i.e., iHPCs. Sixteen weeks after transplantation into WD mice, approximately 2% of hepatocytes were derived from iHPCs, and these iHPC-derived hepatocytes expressed a tight junction-associated protein of the bile canal, tight junction protein 1 (Zo1). There was a decrease in the serum copper concentration and relative activity of serum ceruloplasmin at weeks 4 and 8 after iHPCs transplantation compared with those of WD fed mice administered saline or fibroblasts. Furthermore, iHPC transplantation markedly reduced the proportion of CD8+ T lymphocytes and natural killer cells compared with those in fibroblast-transplanted WD mice and downregulated the transcription of the inflammatory cytokines, including tumor necrosis factor α (Tnfα), interleukin 1β (IL-1β), and IL-6, compared with those in WD mice and in fibroblast-transplanted WD mice. iHPCs reprogrammed from adult fibroblasts can repopulate hepatocytes and exert therapeutic effects in WD mice, representing a potential replacement therapy for clinical application. Simultaneous overexpression of Foxa3 and Hnf4α can reprogram fibroblasts into homogenous hepatic progenitor cells. After transplantation, these reprogrammed hepatic progenitor cells integrate into liver tissue and participate in liver copper excretion and serum copper reduction in WD mice. Compared with those in fibroblast-transplanted WD mice, transplantation of these reprogrammed hepatic progenitor cells markedly reduced the proportions of CD8+ T lymphocytes and natural killer cells and downregulated the transcription of the inflammatory cytokines Tnfα, IL-1β, and IL-6.