Up-regulation of CXCR4 in rat umbilical mesenchymal stem cells induced by serum from rat with acute liver failure promotes stem cells migration to injured liver tissue

The role of C-X-C chemokine receptor type 4 (CXCR4) in umbilical mesenchymal stem cells (UMSCs) as therapy for liver disease is ill understood. The aim of the study was to evaluate rat UMSCs (rUMSCs) on CXCR4 expression and homing to injured liver tissue. rUMSCs were isolated from umbilical cords of pregnant rats. Acute liver failure (ALF) models were developed using d-galactosamine. CXCR4 expression induction by serum from rats with ALF (LFS), cytokines, growth factors, and LPS was analyzed. CXCR4 expression was analyzed by RT-PCR, western blot, and flow cytometry. rUMSCs were labeled with carboxyfluorescein and pretreated with LFS to induce CXCR4 expression and were transplanted into ALF rats. Animals were sacrificed 48 h and 1 week after transplantation. Liver-homing rUMSCs were observed under fluorescence microscopy. rUMSCs were successfully isolated, expressing CD90 and CD106, but not CD34 and CD45. mRNA and protein expressions of CXCR4 were strongly up-regulated by LFS and by the mixture of cytokines, stem cell factor, and LPS (CM). Expression of cell surface CXCR4 on rUMSCs in groups treated with LFS (42.37 +/- A 1.60 %) and CM (40.17 +/- A 1.78 %) was higher than that in the untreated control group (9.67 +/- A 1.06 %) (both P < 0.001). At 48 h after transplantation, more rUMSCs pretreated with LFS appeared in the portal area, and migrated to the liver parenchyma after 1 week. LFS strongly induced the surface expression of CXCR4 on rUMSCs. Increasing CXCR4 expression on rUMSCs may enhance their homing ability to injured liver tissue, and may eventually be used for treating liver diseases.