Successful energy shift from glycolysis to mitochondrial oxidative phosphorylation in freshly isolated hepatocytes from humanized mice liver

Toxicol In Vitro. 2020 Jun;65:104785. doi: 10.1016/j.tiv.2020.104785. Epub 2020 Jan 25.

Abstract

Mitochondrial toxicity is a factor of drug-induced liver injury. Previously, we reported an in vitro rat hepatocyte assay where mitochondrial toxicity was more sensitively evaluated, using sugar resource substitution and increased oxygen supply. Although this method could be applicable to human cell-based assay, cryopreserved human hepatocyte (CHH) has some disadvantages/uncertainty, including unstable same donor supply and potential organelle damage due to cryopreservation. Herein, we compared the mitochondrial functions of freshly-isolated hepatocytes from humanized chimeric mice liver (PXB-cells) and three CHH lots to determine the better cell source for mitochondrial toxicity assay. Two CHH lots declined after replacing glucose with galactose. To confirm the shift in energy production from glycolysis to oxidative phosphorylation, lactate and oxygen consumption rate (indicators of glycolytic activity and mitochondrial oxidative phosphorylation, respectively) were measured. In PXB-cells, lactate amount decreased, while oxygen consumption in 100 min increased. These effects were less evident in CHH. The cytotoxicity of the select respiratory chain inhibitors was enhanced in PXB-cells upon sugar replacement, but no change occurred with negative control drugs (bicalutamide and metformin). Altogether, PXB-cells was less vulnerable to sugar resource substitution than CHH. The substitution activated mitochondrial function and enhanced cytotoxicity of respiratory chain inhibitors in PXB-cells.

Keywords: Cryopreserved human hepatocyte; Drug-induced liver injury; Mitochondria; PXB-cell; Sugar resource substitution.

MeSH terms

  • Animals
  • Cell Line
  • Glycolysis*
  • Hepatocytes / metabolism*
  • Lactic Acid / metabolism
  • Liver / metabolism
  • Mice
  • Mitochondria, Liver / metabolism*
  • Oxidative Phosphorylation*
  • Oxygen Consumption

Substances

  • Lactic Acid