Identification of cytokines involved in hepatic differentiation of mBM-MSCs under liver-injury conditions

AIM: To identify the key cytokines involved in hepatic differentiation of mouse bone marrow mesenchymal stem cells (mBM-MSCs) under liver-injury conditions. METHODS: Abdominal injection of CCl4 was adopted to duplicate a mouse acute liver injury model. Global gene expression analysis was performed to evaluate the potential genes involved in hepatic commitment under liver-injury conditions. The cytokines involved in hepatic differentiation of mBM-MSCs was function-ally examined by depletion experiment using specifi c antibodies, followed by rescue experiment and direct inducing assay. The hepatic differentiation was characterized by the expression of hepatic lineage genes and proteins, as well as functional features. RESULTS: Cytokines potentially participating in hepatic fate commitment under liver-injury conditions were initially measured by microarray. Among the up-regulated genes determined, 18 cytokines known to closely relate to liver growth, repair and development, were selected for further identif ication. The f ibroblast growth factor-4 (FGF-4), hepatocyte growth factor (HGF) and oncostatin M (OSM) were fi nally found to be involved in hepatic differentiation of mBM-MSCs under liver-injury conditions. Hepatic differentiation could be dramatically decreased after removing FGF-4, HGF and OSM from the liver-injury conditioned medium, and could be rescued by supplementing these cytokines. The FGF-4, HGF and OSM play different roles in the hepatic differentiation of mBM-MSCs, in which FGF-4 and HGF are essential for the initiation of hepatic differentiation, while OSM is critical for the maturation of hepatocytes. CONCLUSION: FGF-4, HGF and OSM are the key cytokines involved in the liver-injury conditioned medium for the hepatic differentiation of mBM-MSCs.