Exosomes Derived From Human Umbilical Cord Mesenchymal Stem Cells Alleviate Acetaminophen-induced Acute Liver Failure Through Activating ERK and IGF-1R/PI3K/AKT Signaling Pathways

Abstract

Background: Human umbilical cord mesenchymal stem cells (hUCMSCs) transplantation has been proposed as a promising therapeutic approach for treating acute liver failure (ALF), but its application is limited by immune rejection and tumor formation. Exosomes contain various bioactive cargos including mRNA, microRNA, and protein that can alter the cellular enviroment to enhance tissue repair. However, the exact effects of hUCMSCs derived exosomes (hUCMSC-Exo) on the healing of ALF and their potential mechanisms are not explored.Methods: In vivo, mouse model of ALF were set up through a single intraperitoneal injection of acetaminophen (APAP, 380 mg/kg). In vitro, human hepatocyte cells LO2 were treated with APAP (5 mM). Then APAP-induced ALF mice and APAP-injured LO2 cells were treated with hUCMSC-Exo. Finally, the effects and the mechanisms were estimated.Results: We found that a single tail vein administration of hucMSC-Exo effectively enhanced the survival rate, inhibited apoptosis in hepatocytes, and improved liver function in APAP-induced mouse model of ALF. Furthermore, the deletion of glutathione (GSH) and superoxide dismutase (SOD), generation of malondialdehyde (MDA), and the over expression of cytochrome P450 E1 (CYP2E1) and 4-hydroxynonenal (4-HNE) caused by APAP were also inhibited by hucMSC-Exo, indicating that hucMSC-Exo inhibited APAP-induced apoptosis of hepatocytes by reducing oxidative stress. Moreover, hucMSC-Exo significantly down-regulated the levels of inflammatory cytokines IL-6, IL-1β, and TNF-α in APAP-treated livers. Western blot showed that hucMSC-Exo significantly promoted the activation of ERK1/2 and IGF-1R/PI3K/AKT signaling pathways in APAP-injured LO2 cells, resulting in the inhibition of apoptosis of LO2 cells. Importantly, PI3K inhibitor LY294002 and ERK1/2 inhibitor PD98059 could reverse the function of hucMSC-Exo on APAP-injured LO2 cells in some extent. Conclusions: Our results suggest that hucMSC-Exo offer antioxidant hepatoprotection against APAP in vitro and in vivo by inhibitiing oxidative stress-induced apoptosis via upregulation of ERK1/2 and PI3K/AKT signaling pathways, suggesting that administration of hucMSC-Exo may be an alternative approach for the treatment of ALF.