Collins Joseph M, Wang Danxin
Department of Pharmacotherapy and Translational Research, College of Pharmacy, Center for Pharmacogenomics and Precision Medicine, University of Florida, Gainesville, Florida.
Department of Pharmacotherapy and Translational Research, College of Pharmacy, Center for Pharmacogenomics and Precision Medicine, University of Florida, Gainesville, Florida.
Drug Metab Dispos. 2025 Jan;53(1):100011. doi: 10.1124/dmd.124.001923. Epub 2024 Nov 22.
Many factors cause interperson variability in the activity and expression of the cytochrome P450 (CYP) drug-metabolizing enzymes in the liver, leading to variable drug exposure and treatment outcomes. Several liver-enriched transcription factors are associated with CYP expression, with estrogen receptor α (ESR1) and constitutive androstane receptor (CAR or NR1I3) being the 2 top factors. ESR1 and NR1I3 undergo extensive alternative splicing that results in numerous splice isoforms, but how these splice isoforms associate with CYP expression is unknown. Here, we quantified 18 NR1I3 splice isoforms and the 3 most abundant ESR1 isoforms in 260 liver samples derived from African Americans (n = 125) and European Americans (n = 135). Our results showed variable splice isoform populations in the liver for both NR1I3 and ESR1. Multiple linear regression analyses revealed that compared with gene-level NR1I3, isoform-level NR1I3 expression better predicted the mRNA expression of most CYPs and 3 UDP-glucuronosyltransferases (UGTs), whereas ESR1 isoforms improved predictive models for the UGTs and CYP2D6 but not for most CYPs. Also, different NR1I3 isoforms were associated with different CYPs, and the associations varied depending on sample ancestry. Surprisingly, noncanonical NR1I3 isoforms having retained introns (introns 2 or 6) were abundantly expressed and associated with the expression of most CYPs and UGTs, whereas the reference isoform (NR1I3-205) was only associated with CYP2D6. Moreover, NR1I3 isoform diversity increased during the differentiation of induced pluripotent stem cells to hepatocytes, paralleling increasing CYP expression. These results suggest that isoform-level transcription factor expression may help to explain variation in CYP or UGT expression between individuals. SIGNIFICANCE STATEMENT: We quantified 18 NR1I3 splice isoforms and the 3 most abundant ESR1 splice isoforms in 260 liver samples derived from African American and European American donors and found variable NR1I3 and ESR1 splice isoform expression in the liver. Multiple linear regression analysis showed that, compared with gene-level expression, isoform-level expression of NR1I3 and ESR1 better predicted the mRNA expression of some cytochrome P450s and UDP-glucuronosyltransferases, highlighting the importance of isoform-level analyses to enhance our understanding of gene transcriptional regulatory networks controlling the expression of drug-metabolizing enzymes.
许多因素导致肝脏中细胞色素P450（CYP）药物代谢酶的活性和表达存在个体间差异，从而导致药物暴露和治疗结果的差异。几种肝脏富集转录因子与CYP表达相关，其中雌激素受体α（ESR1）和组成型雄甾烷受体（CAR或NR1I3）是两个主要因素。ESR1和NR1I3经历广泛的可变剪接，产生大量剪接异构体，但这些剪接异构体如何与CYP表达相关尚不清楚。在这里，我们对来自非裔美国人（n = 125）和欧裔美国人（n = 135）的260份肝脏样本中的18种NR1I3剪接异构体和3种最丰富的ESR1异构体进行了定量。我们的结果显示，肝脏中NR1I3和ESR1的剪接异构体群体存在差异。多元线性回归分析显示，与基因水平的NR1I3相比，异构体水平的NR1I3表达能更好地预测大多数CYP和3种尿苷二磷酸葡萄糖醛酸转移酶（UGT）的mRNA表达，而ESR1异构体改善了UGT和CYP2D6的预测模型，但对大多数CYP则不然。此外，不同的NR1I3异构体与不同的CYP相关，且这种关联因样本血统而异。令人惊讶的是，保留内含子（内含子2或6）的非经典NR1I3异构体大量表达，并与大多数CYP和UGT的表达相关，而参考异构体（NR1I3-205）仅与CYP2D6相关。此外，在诱导多能干细胞向肝细胞分化过程中，NR1I3异构体多样性增加，与CYP表达增加平行。这些结果表明，异构体水平的转录因子表达可能有助于解释个体间CYP或UGT表达的差异。重要声明：我们对来自非裔美国人和欧裔美国人捐赠者的260份肝脏样本中的18种NR1I3剪接异构体和3种最丰富的ESR1剪接异构体进行了定量，发现肝脏中NR1I3和ESR1剪接异构体表达存在差异。多元线性回归分析表明，与基因水平表达相比，NR1I3和ESR1的异构体水平表达能更好地预测某些细胞色素P450和尿苷二磷酸葡萄糖醛酸转移酶的mRNA表达，突出了异构体水平分析对于增强我们对控制药物代谢酶表达的基因转录调控网络理解的重要性。
