Evaluation of mRNA expression of drug-metabolizing enzymes in acetaminophen-induced hepatotoxicity using a three-dimensional hepatocyte culture system

Abstract

1. The expression and activity of drug-metabolizing enzymes are known to affect the pharmacokinetics of drugs metabolized in the liver. Here, we assessed the effect of acetaminophen (APAP)-induced hepatotoxicity on the mRNA expression of drug-metabolizing enzymes and elucidated the underlying mechanism using three-dimensional (3D) cultures of HepG2 cells.

2. 3D culture cells enabled us to establish an in vitro model of APAP-induced hepatotoxicity which showed the increase in N-acetyl-p-benzoquinone imine production, reactive oxygen species (ROS) generation and cellular injury.

3. In this 3D culture model, APAP treatment significantly increased the mRNA expression of drug-metabolizing enzymes (cytochrome P450 [CYP]3A4, CYP2E1 and UDP-glucuronosyltransferase 1A6) and their nuclear receptors (pregnane X receptor and constitutive androstane receptor) compared with untreated cells. Treatment with N-acetylcysteine, a therapeutic agent for APAP-induced hepatotoxicity, suppressed these increases. In addition, the mRNA expression of drug-metabolizing enzymes and nuclear receptors were elevated depending on the concentration of H₂O₂, one of ROS involved in the development of APAP-induced hepatotoxicity. The mRNA expression of nuclear receptors increased before that of drug-metabolizing enzymes.

4. In conclusion, ROS may induce the mRNA expression of nuclear receptors and promote the transcription of drug-metabolizing enzymes in the in vitro model of APAP-induced hepatotoxicity.

Keywords:

• Acetaminophen-induced hepatotoxicity
• cytochrome P450
• pregnane X receptor
• constitutive androstane receptor
• reactive oxygen species
• three-dimensional cell model

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by JSPS KAKENHI Grant Number 16K18947.