Pregnane X receptor- and CYP3A4-humanized mouse models and their applications

Area of Science:

• Pharmacology and Toxicology
• Molecular Biology
• Genetics

Background:

• The Pregnane X receptor (PXR) is a nuclear receptor crucial for regulating xenobiotic metabolism.
• PXR primarily controls the expression of CYP3A4, a key enzyme in human drug metabolism.
• Significant species-specific differences exist in how PXR recognizes and binds to various ligands.

Purpose of the Study:

• To establish and validate mouse models that express human PXR (hPXR) and both human PXR and CYP3A4 (Tg3A4/hPXR).
• To enable more accurate preclinical investigations into PXR's role in drug metabolism and toxicity.
• To explore PXR's influence on homeostasis of lipids, bile acids, and steroid hormones, as well as its role in inflammation.

Main Methods:

• Development of genetically engineered mouse lines expressing human PXR.
• Generation of a second mouse line co-expressing human PXR and human CYP3A4.
• Utilizing these humanized mouse models for preclinical research.

Main Results:

• Successfully established hPXR and Tg3A4/hPXR mouse models.
• These models accurately reflect human PXR-mediated responses relevant to xenobiotic metabolism.
• Demonstrated the utility of these models for studying PXR's broader physiological roles.

Conclusions:

• Humanized mouse models (hPXR and Tg3A4/hPXR) are essential tools for studying human PXR function.
• These models overcome limitations posed by species differences in PXR ligand recognition.
• They facilitate research into drug metabolism, toxicity, homeostasis, and inflammation controlled by PXR.