Fashe Muluneh M, Miner Taryn A, Collazo Valeria Laboy, Grieco Joseph T, Fallon John K, Jackson Klarissa D, Lee Craig R
Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
Division of Pharmacoengineering and Molecular Pharmaceutics, and Center for Nanotechnology in Drug Delivery, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
Drug Metab Dispos. 2025 Feb;53(2):100025. doi: 10.1016/j.dmd.2024.100025. Epub 2024 Nov 29.
Cytochrome P450 (CYP) 3A4 is an essential drug-metabolizing enzyme in humans, which shows substantial interindividual variation in response to various intrinsic and extrinsic factors such as sex and pregnancy. In humans, higher CYP3A4 metabolism has been observed in females compared with that in males and in pregnant compared with that in nonpregnant individuals, which has been linked to increased CYP3A4 expression in liver. However, sex differences and pregnancy-mediated changes in hepatic CYP3A4 expression and activity in vivo are not fully understood. In this study, we investigated the utility of a genetically engineered humanized mouse model that carries human CYP3A4/7, pregnane X receptor (PXR) and constitutive androstane receptor (CAR) (huPXR/CAR/CYP3A4/7) to recapitulate sex-associated and pregnancy-associated differences in the hepatic CYP3A4 expression and metabolism observed in humans. We found that female huPXR/CAR/CYP3A4/7 mice exhibited higher basal CYP3A4 mRNA levels and CYP3A4 absolute protein concentrations in liver, and higher 1-hydroxymidazolam formation in liver microsomes, compared with male humanized mice. In contrast, pregnant huPXR/CAR/CYP3A4/7 mice exhibited lower CYP3A4 mRNA levels, CYP3A4 absolute protein concentrations, and 1-hydroxymidazolam formation compared with nonpregnant and postpartum humanized mice. Expression of CAR and Cyp2b10 (a CAR responsive gene) were also higher in females and decreased during pregnancy and were positively correlated with hepatic CYP3A4 mRNA levels. Overall, the huPXR/CAR/CYP3A4/7 mouse model demonstrated utility to study higher basal hepatic CYP3A4 metabolism in females compared with that in males in vivo; however, this humanized mouse model did not demonstrate utility to study pregnancy-mediated increases in CYP3A4 drug substrate metabolism and clearance observed in humans. SIGNIFICANCE STATEMENT: This study assessed the impact of sex and pregnancy on hepatic CYP3A4 protein concentrations and metabolism in humanized PXR/CAR/CYP3A4 mice. Consistent with humans, female mice demonstrated higher hepatic CYP3A4 expression and activity than male mice. In contrast, pregnant mice showed decreased CYP3A4 expression and metabolism compared with nonpregnant mice. The humanized mouse model appeared useful to evaluate sex differences in basal hepatic CYP3A4 metabolism in vivo, but not to study the pregnancy-mediated increase in CYP3A4 metabolism observed during human pregnancy.
细胞色素P450（CYP）3A4是人体内一种重要的药物代谢酶，其对各种内在和外在因素（如性别和妊娠）的反应存在显著的个体间差异。在人类中，与男性相比，女性以及与未怀孕个体相比，怀孕个体的CYP3A4代谢更高，这与肝脏中CYP3A4表达增加有关。然而，体内肝脏CYP3A4表达和活性的性别差异以及妊娠介导的变化尚未完全了解。在本研究中，我们研究了一种携带人CYP3A4/7、孕烷X受体（PXR）和组成型雄甾烷受体（CAR）（huPXR/CAR/CYP3A4/7）的基因工程人源化小鼠模型在重现人类肝脏CYP3A4表达和代谢中与性别相关及妊娠相关差异方面的效用。我们发现，与雄性人源化小鼠相比，雌性huPXR/CAR/CYP3A4/7小鼠肝脏中的基础CYP3A4 mRNA水平、CYP3A4绝对蛋白浓度更高，且肝脏微粒体中1-羟基咪达唑仑的生成更多。相比之下，与未怀孕和产后人源化小鼠相比，怀孕的huPXR/CAR/CYP3A4/7小鼠的CYP3A4 mRNA水平、CYP3A4绝对蛋白浓度和1-羟基咪达唑仑生成更低。CAR和Cyp2b10（一种CAR反应基因）的表达在雌性中也更高，在怀孕期间降低，且与肝脏CYP3A4 mRNA水平呈正相关。总体而言，huPXR/CAR/CYP3A4/7小鼠模型证明了在体内研究雌性与雄性相比更高的基础肝脏CYP3A4代谢方面的效用；然而，这种人源化小鼠模型在研究人类中观察到的妊娠介导的CYP3A4药物底物代谢和清除增加方面未显示出效用。意义声明：本研究评估了性别和妊娠对人源化PXR/CAR/CYP3A4小鼠肝脏CYP3A4蛋白浓度和代谢的影响。与人类一致，雌性小鼠的肝脏CYP3A4表达和活性高于雄性小鼠。相比之下，与未怀孕小鼠相比，怀孕小鼠的CYP3A4表达和代谢降低。人源化小鼠模型似乎有助于评估体内基础肝脏CYP3A4代谢的性别差异，但无助于研究人类妊娠期间观察到的妊娠介导的CYP3A4代谢增加。
