Magnetotactic hepatocytes promote liver repopulation after transplantation

Clinical application of hepatocyte transplantation has been halted due to the low engraftment efficiency and limited proliferation capacity of donor hepatocytes in the host liver. Here, we developed a magneto-plasmonic nanohybrid to spatiotemporally drive the primary hepatocytes into the host liver under the external magnetic field that significantly improves the engraftment efficiency of donor hepatocytes. A magnetic lipid-coated-gold-nanorods/iron-oxide nanocluster (GNR-IO) (LGI) was designed for efficient magneto-actuation and photoacoustic imaging-guided cell tracking during the hepatocyte transplantation. By optimizing the concentration of LGI (100 μg /mL) and the configuration of a magnetic field (260 mT), we were able to increase the engraftment efficiency of primary hepatocytes into the host livers of Fah-/- mice, a model with the genetic deficit of fumarylacetoacetate hydrolase (FAH) resulting in liver injuries, for 3.89-fold of the control by one week of the transplantation. Further assessment of repopulation of hepatocytes in the host liver indicated the LGI (100 μg /mL) + magnetic field (260 mT) group had up to 15 % repopulation of the host liver by three-weeks-post-transplantation and reached full repopulation by 6-weeks-post-transplantation. This was 3 ∼ 5 times more rapid than the Fah-/- mice transplanted with hepatocytes without the LGI and the magnetic field. RNA-sequencing of the hepatocytes incubated with LGI indicated that the loading of LGIs enhanced the migration, survival, and engraftment of hepatocytes by regulating the tumor necrosis factor (TNF)-signaling pathway and reducing the macrophage in host liver. Furthermore, LGI-labeled hepatocytes could be tracked in host livers with photoacoustic imaging for at least one week post transplantation. Most of the LGI-labeled hepatocytes were cleared from the host systems via the kidneys by six weeks. The novel strategy established in this study, which utilized nanoparticles combined with the magnetic field to improve the efficiency of primary hepatocyte engraftment and repopulation, can provide a feasible scheme for the clinical application of hepatocyte transplantation in the treatment of liver failure.