Liu Wanqing, Ramírez Jacqueline, Gamazon Eric R, Mirkov Snezana, Chen Peixian, Wu Kehua, Sun Chang, Cox Nancy J, Cook Edwin, Das Soma, Ratain Mark J
Department of Medicine and Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA and.
Department of Medicine and.
Hum Mol Genet. 2014 Oct 15;23(20):5558-69. doi: 10.1093/hmg/ddu268. Epub 2014 May 30.
The aim of this study was to discover cis- and trans-acting factors significantly affecting mRNA expression and catalytic activity of human hepatic UDP-glucuronosyltransferases (UGTs). Transcription levels of five major hepatic UGT1A (UGT1A1, UGT1A3, UGT1A4, UGT1A6 and UGT1A9) and five UGT2B (UGT2B4, UGT2B7, UGT2B10, UGT2B15 and UGT2B17) genes were quantified in human liver tissue samples (n = 125) using real-time PCR. Glucuronidation activities of 14 substrates were measured in 47 livers. We genotyped 167 tagSNPs (single-nucleotide polymorphisms) in UGT1A (n = 43) and UGT2B (n = 124), as well as the known functional UGT1A1*28 and UGT2B17 CNV (copy number variation) polymorphisms. Transcription levels of 15 transcription factors (TFs) known to regulate these UGTs were quantified. We found that UGT expression and activity were highly variable among the livers (median and range of coefficient of variations: 135%, 74-217% and 52%, 39-105%, respectively). CAR, PXR and ESR1 were found to be the most important trans-regulators of UGT transcription (median and range of correlation coefficients: 46%, 6-58%; 47%, 9-58%; and 52%, 24-75%, respectively). Hepatic UGT activities were mainly determined by UGT gene transcription levels. Twenty-one polymorphisms were significantly (FDR-adjusted P < 0.05) associated with mRNA expression and/or activities of UGT1A1, UGT1A3 and UGT2B17. We found novel SNPs in the UGT2B17 CNV region accounting for variability in UGT2B17 gene transcription and testosterone glucuronidation rate, in addition to that attributable to the UGT2B17 CNV. Our study discovered novel pharmacogenetic markers and provided detailed insight into the genetic network regulating hepatic UGTs.
本研究的目的是发现显著影响人肝脏UDP-葡萄糖醛酸基转移酶（UGTs）mRNA表达和催化活性的顺式和反式作用因子。使用实时PCR对125份人肝组织样本中5种主要肝脏UGT1A（UGT1A1、UGT1A3、UGT1A4、UGT1A6和UGT1A9）和5种UGT2B（UGT2B4、UGT2B7、UGT2B10、UGT2B15和UGT2B17）基因的转录水平进行定量。在47个肝脏中测量了14种底物的葡萄糖醛酸化活性。我们对UGT1A（n = 43）和UGT2B（n = 124）中的167个标签单核苷酸多态性（tagSNPs）以及已知的功能性UGT1A1*28和UGT2B17拷贝数变异（CNV）多态性进行了基因分型。对已知调节这些UGT的15种转录因子（TFs）的转录水平进行了定量。我们发现肝脏之间UGT的表达和活性高度可变（变异系数的中位数和范围分别为：135%，74 - 217%和52%，39 - 105%）。发现CAR、PXR和ESR1是UGT转录最重要的反式调节因子（相关系数的中位数和范围分别为：46%，6 - 58%；47%，9 - 58%；52%，24 - 75%）。肝脏UGT活性主要由UGT基因转录水平决定。21种多态性与UGT1A1、UGT1A3和UGT2B17的mRNA表达和/或活性显著相关（FDR校正P < 0.05）。除了归因于UGT2B17 CNV的变异外，我们在UGT2B17 CNV区域发现了新的SNP，其解释了UGT2B17基因转录和睾酮葡萄糖醛酸化率的变异性。我们的研究发现了新的药物遗传学标记，并对调节肝脏UGT的遗传网络提供了详细的见解。
