Transcriptomics confirm the establishment of a liver‐immune dual‐humanized mouse model after transplantation of a single type of human bone marrow mesenchymal stem cell

Background and Aims Human bone marrow mesenchymal stem cells (hBMSCs) are important for developing a dual‐humanized mouse model to clarify disease pathogenesis. We aimed to elucidate the characteristics of hBMSC transdifferentiation into liver and immune cells. Methods A single type of hBMSCs was transplanted into immunodeficient Fah−/− Rag2−/− IL‐2Rγc−/− SCID (FRGS) mice with fulminant hepatic failure (FHF). Liver transcriptional data from the hBMSC‐transplanted mice were analysed to identify transdifferentiation with traces of liver and immune chimerism. Results Mice with FHF were rescued by implanted hBMSCs. Human albumin/leukocyte antigen (HLA) and CD45/HLA double‐positive hepatocytes and immune cells were observed in the rescued mice during the initial 3 days. The transcriptomics analysis of liver tissues from dual‐humanized mice identified two transdifferentiation phases (cellular proliferation at 1–5 days and cellular differentiation/maturation at 5–14 days) and ten cell lineages transdifferentiated from hBMSCs: human hepatocytes, cholangiocytes, stellate cells, myofibroblasts, endothelial cells and immune cells (T/B/NK/NKT/Kupffer cells). Two biological processes, hepatic metabolism and liver regeneration, were characterized in the first phase, and two additional biological processes, immune cell growth and extracellular matrix (ECM) regulation, were observed in the second phase. Immunohistochemistry verified that the ten hBMSC‐derived liver and immune cells were present in the livers of dual‐humanized mice. Conclusions A syngeneic liver‐immune dual‐humanized mouse model was developed by transplanting a single type of hBMSC. Four biological processes linked to the transdifferentiation and biological functions of ten human liver and immune cell lineages were identified, which may help to elucidate the molecular basis of this dual‐humanized mouse model for further clarifying disease pathogenesis.