Generating P450dTAG knock-in mouse models for drug metabolism and pharmacokinetics

About This Grant

ABSTRACT Drug metabolism and pharmacokinetics (DMPK) is critical for the successful development of new drugs ensuring they are both effective and safe for clinical use. Cytochrome P450 enzymes (P450s) are crucial in drug metabolism, responsible for the metabolism of approximately 75% of all marketed drugs. Determining the specific contribution of individual P450 enzyme to the metabolism of drugs facilitates understanding the role of a specific P450 isoform in pharmacokinetics, drug-drug interactions, and drug toxicity. Currently, P450- knockout animal models and specific chemical inhibitors are commonly used for these purposes. However, highly specific and effective chemical inhibitors in vivo are frequently unavailable. Although P450-KO mice are invaluable, the deletion of a specific or a cluster of P450 gene(s) can lead to compensatory changes of other P450s and cause developmental, or physiological abnormalities. Thus, creating new models to specifically manipulate P450s activities without the compensatory effects are extremely needed for DMPK studies. The state-of-the-art dTAG (degradable tag) system is a targeted protein degradation technology that enables the selective, rapid, and reversible degradation of a protein of interest within living cells or organisms. The unique features of dTAG system (e.g., minimizing the compensatory effects) render it ideal to generate animal model for assessing the impact of specific enzymes, transporters, or receptors on DMPK of drugs, especially for globally knocking out lethal genes (e.g., P450 reductase). In this proposal, we will employ dTAG system to create Cyp1a2dTAG and Cyp3a11dTAG models. Three Aims will be pursued: Aim 1: To generate and characterize Cyp1a2dTAG and Cyp3a11dTAG mice. Aim 2: To optimize dTAG molecule properties. Aim 3: To develop protocols to probe the roles of P450s in DMPK using homozygous P450dTAG mice. The proposed work is innovative as using dTAG system to modulate the drug metabolizing enzyme represents a transformative approach in this field. After completing the proposed work, we expect that two novel Cyp1a2dTAG and Cyp3a11dTAG mouse models that overcome the drawbacks of traditional models will be created and dTAG molecules that exhibit favorable physiological and pharmacokinetic properties will be developed. Our long-term goal is to extend the application of dTAG technology to regulate other significant drug metabolizing enzymes such as Cyp2d22, Cyp2e1, UGTs, and transporters, which will create a series of novel animal models for DMPK, toxicity, and functional studies. This work will have a great potential to significantly advance the fields of preclinical DMPK studies in drug development, and toxicity.