Successful energy shift from glycolysis to mitochondrial oxidative phosphorylation in freshly isolated hepatocytes from humanized mice liver. (June 2020)

• Record Type: Journal Article
• Authors: Ikeyama, Yugo; Sato, Tomoyuki; Takemura, Akinori; Sekine, Shuichi; Ito, Kousei
• Is Part Of: Toxicology in vitro. Volume 65(2020)
• Publication Date: 2020-06
• Subjects: Drug-induced liver injury -- Mitochondria -- Sugar resource substitution -- PXB-cell -- Cryopreserved human hepatocyte; Drug-induced liver injury DILI -- Respiratory chain inhibitor RCI -- Reactive oxygen species ROS -- Mitochondrial permeability transition MPT -- Oxidative phosphorylation OXPHOS -- Cryopreserved human hepatocytes CHH -- Williams' medium E WME -- Lactate dehydrogenase LDH; Toxicity testing -- In vitro -- Periodicals; Toxicology -- Periodicals; 615.9
• DOI: 10.1016/j.tiv.2020.104785
• Languages: English
• ISSNs: 0887-2333

Abstract

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. Graphical abstract: Unlabelled Image Highlights: Cryopreservation damages mitochondria but not of freshly isolated PXB-cells. PXB-cells are compatible with the replacement of sugar resource in the medium. PXB-cells have enhanced mitochondrial function. PXB-cells are useful for mitochondrial toxicity assay.