Glutathione Peroxidase 3 (GPx3) Delivered by hiPSC-MSCs Ameliorated Hepatic IR Injuries Via Inhibition of Hepatic Senescence

Abstract

Introduction: Down-regulation of GPx3 accelerated hepatic senescence, which further caused overwhelming inflammation and severe liver graft injury[1]. MSC derived from human induced pluripotent stem cells (hiPSC-MSC) has been developed as more efficient delivery vehicle with the property of injury tropism[2]. Here, we aimed to explore the suppressive role of GPx3 in hepatic IR injury using novel delivery system of hiPSC-MSCs.

Methods: The mice IR injury model with partial hepatectomy was established. The novel delivery system, hiPSC-MSC-GPx3, was constructed. All the mice were segregated into three groups. hiPSC-MSC-GPx3, hiPSC-MSC-pCDH (vector control) or PBS were injected via portal vein after reperfusion. Liver injury was evaluated by histological and serological test. Hepatic apoptosis was detected by Tunel staining and remnant liver regeneration was assessed by Ki67 staining. The role of hepatic senescence in liver graft injury was evaluated in rat orthotopic liver transplantation model. The suppressive effect of GPx3 on hepatic senescence was examined in mice IR injury model and confirmed in vitro. Hepatic senescence was detected by SA-β-Gal and P16/ink4a staining.

Results: GPx3 can be successfully delivered by hiPSC-MSCs system into liver tissues. Histological examination showed that hiPSC-MSC-GPx3 treatment significantly ameliorated hepatic IR injury post-operation. Significantly lower LDH (891.43±98.45 mU/mL, P<0.05) and AST (305.77±36.22 IU/L, P<0.01) were observed in hiPSC-MSC-GPx3 group post-operation compared with control groups. Apoptotic hepatocytes were significantly lower and the remnant liver regeneration was significantly more active in hiPSC-MSC-GPx3 group. In rat orthotopic liver transplantation model, more senescent hepatocytes were observed in small-for-size liver graft, in which liver injury was more severe. In mice IR injury model, hiPSC-MSC-GPx3 significantly inhibited hepatic senescence. In addition, rGPx3 inhibited cellular senescence of liver cell lines in a dose dependent manner. The suppressive effect of GPx3 on hepatic senescence was mediated via down-regulation of cyclin-dependent kinase inhibitor p21.

Conclusion: GPx3 treatment using hiPSC-MSC as delivery vehicle ameliorated hepatic IR injury via inhibition of hepatic senescence.