The metabolic profiles of endogenous and exogenous substances in a poor metabolizer of humanized CYP2D6 model

Species differences in CYP2D6 drug metabolism complicate the extrapolation of in vivo pharmacokinetic data to humans and impact the prediction of drug responses. This study aimed to develop an in vivo model to predict human responses to CYP2D6 metabolized compounds and to evaluate medication risks and disease development.

We used embryonic stem cell (ES) targeting and CRISPR-Cas9 technology to create a humanized CYP2D6 mouse model by inserting the human wild-type CYP2D6 gene and knocking out the mouse Cyp2d locus. Metoprolol was used as the substrate probe to examine the pharmacokinetic properties of exogenous substances, tissue distribution, and in situ metabolism of CYP2D6. Untargeted and quantitative metabolomics analyses compared endogenous substance metabolism between different species of CYP2D6 enzymes.

No significant differences in CYP2D6 homologous protein distribution and expression of primary metabolic organs were found between humanized CYP2D6 mice and wild-type (WT) mice. The activity and metabolic capacity of CYP2D6 in humanized mice were substantially lower than homologous Cyp2d22 of WT mice in metabolizing metoprolol. The levels of several glycerolipids and glycerophospholipid-related metabolites were down-regulated in humanized CYP2D6 mice. Triglyceride TG (14:0_22:6_22:6) was significantly downregulated in male and female humanized mice, suggesting a strong association with reduced CYP2D6 activity.

This study established a robust animal model to investigate human CYP2D6-mediated metabolic profiles of exogenous and endogenous compounds, predict medication risks, and explore the potential roles of CYP2D6 in organ-specific toxicity and disease development.