Abstract
Mitochondrial damage is considered a hallmark of drug-induced liver injury (DILI). However, despite the common molecular etiology, the evolution of the injury is usually unpredictable, with some cases that are mild and reversible upon discontinuation of the treatment and others characterized by irreversible acute liver failure. This suggests that additional mechanisms of damage play a role in determining the progression of the initial insult. To uncover novel pathways potentially involved in DILI, we investigated in vitro the metabolic perturbations associated with nefazodone, an antidepressant associated with acute liver failure. Several pathways associated with ATP production, including gluconeogenesis, anaerobic glycolysis and oxidative phosphorylation, were altered in human hepatocellular carcinoma-derived (Huh7) cells after two hour-exposure to a 50 microM extracellular concentration of nefazodone. In the presence or absence of glucose, ATP production of Huh7 cells was glycolysis- and oxidative phosphorylation-dependent, respectively. In glucose-containing medium, nefazodone-induced ATP depletion from Huh7 cells was biphasic. Huh7 cells in glucose-free medium were more sensitive to nefazodone than those in glucose-containing medium, losing the biphasic inhibition. Primary cultured mouse hepatocytes, mainly dependent on oxidative phosphorylation, were more sensitive than Huh7 cells to nefazodone exposure in glucose containing medium. At lower extracellular concentrations, nefazodone inhibited the oxygen consumption of Huh7 cells, whereas, at higher extracellular concentrations, it also inhibited the extracellular acidification. ATP content was rescued by increasing the extracellular concentration of glucose. In conclusion, nefazodone has a dual inhibitory effect on mitochondrial-dependent and mitochondrial-independent ATP production.
Krajnc, Evelin