Adipose mesenchymal stem cell-derived exosomes (ADMSC-Exo) are a new strategy for the treatment of liver injury. However, mesenchymal stem cells (MSCs) exert therapeutic effects mainly by secreting hepatocyte growth factor (HGF). Therefore, we investigated the role of exosomes derived from ADMSC that overexpress HGF (ADMSCHGF-Exo) on liver injury.
Material and methods: ADMSCs were isolated from young BALB/c female mice. Then exosomes derived from ADMSC transfecting negative control (ADMSCNC-Exo) and HGF overexpression (ADMSCHGF-Exo) were isolated and identified by quantitative polymerase chain reaction (qPCR), flow cytometry, western blot, transmission electron microscope and Nanosight particle tracking analysis. These exosomes were injected into male mice via tail vein after inducing liver injury by administering 40% carbon tetrachloride (CCl₄)-olive oil twice a week (3 mL/kg, subcutaneously) for 6 weeks. Liver injury and liver collagen fiber accumulation were determined by histopathological analysis. Then, the levels of serum liver function indexes (alanine aminotransferase, aspartate aminotransferase, albumin, total bilirubin), hepatocyte-specific markers (albumin, cytokeratin-18 and hepatocyte nuclear factor 4α), hepatic fibrosis-related proteins (α-smooth muscle actin and collagen I) and Rho GTPase (cell division cycle 42 and ras-related C3 botulinum toxin substrate 1) were determined by Enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, Western blot and qPCR.
Results: ADMSCs were identified by high expression of CD105 and CD44 molecules and low expression of CD45 and CD34. ADMSCs-Exo, ADMSCNC-Exo and ADMSCHGF-Exo transfected cells had similar expression of exosome-specific membrane proteins (CD63, CD81 and CD9). Mice with CCl₄-induced liver injury exhibited abnormal serum liver function indexes, altered expression of hepatocyte-specific markers, hepatic fibrosis-related proteins and Rho GTPase protein as well as histopathological changes and collagen fiber accumulation in the liver. These changes were reversed by ADMSC-Exo, ADMSCNC-Exo and ADMSCHGF-Exo administration with ADMSCHGF-Exo displaying the most significant impact.
Conclusions: ADMSCHGF-Exo exerted a hepatoprotective effect in mice with experimental liver injury by alleviating hepatic fibrosis and restoring liver function.
Keywords: Hepatocyte growth factor; Rho GTPase; adipose mesenchymal stem cells; exosome; liver injury.