Study on defect in human UGTIAI gene promoter associated with hyperbilirubinemia and mechanism of the UGTIAI in duction

与高胆红素血症相关的人UGTIAI基因启动子缺陷及其诱导机制研究

• 批准号: 14572057
• 负责人: SUGATANI Junko
• 金额: $ 2.24万
• 依托单位: University of Shizuoka
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14572057/
• 关键词: bilirubin LIDP-glucuronosyltransferase(UGT1A1); Gilbert's syndrome; hyperbilirubinemia; bilirubin; single nucleotide polymorphism(SNP); nuclear receptor; flavonoids; フラボノイド; UGT1A1; プロモーター遺伝子

The UDP-glucuronosyltransferase UGT1A1 plays a critical role in the detoxification of potentially neurotoxic bilirubin by conjugating it with glucuronic acid. We identified a polymorphism that results in a T to G substitution at nucleotide number -3263 of the phenobarbital-responsive enhancer module of the UGT1A1 gene, thereby significantly decreaseing transcriptional activity as indicated by the luciferase-reporter assay. Plasma total bilirubin levels in these double heterozygotes were significantly higher than those in control subjects carrying one or other of these mutations singly, indicating that compound heterozygous mutations may result in more strongly reduced UGT1A1 activity. Our results indicate that homozygocity and compound heterozygocity for mutations in the UGT1A1 gene promoter (T-3263G and A[TA]_7TAA) and/or exon 1 of the gene (G211A) could explain the hyperbilirubinemia seen in the majority of individuals with Gilbert's syndrome. Furthermore, we identified the UDP-glucu … More ronosyltransferase UGT1A1 5' -upstream region that confers UGT1A1 induction by various agents, including flavonoids, on a luciferase reporter gene and has the properties of a transcriptional enhancer. Chrysin-and rifampicin-respones activities were traced to the same element as a 290-bp distal enhancer module (-3483/-3194), in which the reporter activites were enhanced by activators of nuclear receptors [constitutive androstane receptor (CAR) and pregnane X receptor (PXR)] and transcription factor [aryl hydrocarbon receptor (AhR)]. Utilizing transactivation experiments with the UGT1A1 290-bp reporter gene, we assessed UGT1A1 induction by various flavonoids. 5,7-Dihydroxyflavones with varying substituents in the B-ring and gallocatechin dimers increased the reporter activity in a time-and dose-dependent manner. Chrysin and rifampicin induced the activation of the wild-type reporter gene and T-3263G-mutated gene to a similar extent in HepG2 cells cotransfected with expression vectors of CAR and PXR. Taken together, the results indicate that UGT1A1 was induced in response to flavonoids and xenobiotics through the transactivation of the 290-bp reporter gene, that was a multi-component enhancer containing CAR, PXR and AhR motifs. Less

UDP-葡萄糖醛酸基转移酶UGT 1A 1通过将胆红素与葡萄糖醛酸结合，在潜在神经毒性胆红素的解毒中发挥关键作用。我们发现了一种多态性，导致UGT 1A 1基因的苯巴比妥响应增强子模块的核苷酸编号-3263处的T变为G，从而显著降低转录活性，如由内切酶报告基因测定所示。这些双杂合子中的血浆总胆红素水平显著高于单独携带这些突变中的一种或另一种的对照受试者，表明复合杂合子突变可能导致UGT 1A 1活性更强烈地降低。我们的研究结果表明，纯合性和复合杂合性突变UGT 1A 1基因启动子（T-3263 G和A[TA]_7 TAA）和/或外显子1的基因（G211 A）可以解释高胆红素血症中看到的大多数个体与吉尔伯特的综合征。此外，我们还鉴定了UDP-葡糖酸， ...更多信息 在一个实施方案中，所述酶包含核糖基转移酶UGT 1A 1 5' -上游区，其在荧光素酶报告基因上赋予UGT 1A 1通过各种试剂（包括类黄酮）的诱导，并且具有转录增强子的性质。将Escherin和利福平应答活性追踪到与290 bp远端增强子模块（-3483/-3194）相同的元件，其中报告活性被核受体激活剂[组成型雄烷受体（CAR）和雄烷X受体（PXR）]和转录因子[芳烃受体（AhR）]增强。利用UGT 1A 1 290 bp报告基因的反式激活实验，我们评估了各种黄酮类化合物对UGT 1A 1的诱导作用。在B环上具有不同取代基的5，7-二羟基黄酮和没食子儿茶素二聚体以时间和剂量依赖性方式增加报告活性。在共转染CAR和PXR表达载体的HepG 2细胞中，利福平和利福平诱导野生型报告基因和T-3263 G突变基因的激活程度相似。综上所述，结果表明，UGT 1A 1是通过290 bp报告基因的反式激活来诱导类黄酮和外源性物质的，该报告基因是包含CAR、PXR和AhR基序的多组分增强子。少

项目成果

J.Sugatani et al.: "The induction of human bilirubin UDP-glucuronosyltransferase mediated through a distal enhancer module by flavonoids and xenobiotics"Biochem.Pharmacol. 67(5). 989-1000 (2004)

J.Sugatani 等人：“类黄酮和异生物质通过远端增强子模块介导人胆红素 UDP-葡萄糖醛酸基转移酶的诱导”Biochem.Pharmacol。

菅谷純子, 三輪匡男: "廣川タンパク質化学第4巻"廣川書店. 12 (2003)

Junko Sugaya、Masao Miwa：《广川蛋白质化学第 4 卷》广川书店 12 (2003)。

J.Sugatani et al.: "Identification of defect in UDP-glucuronosyltransferae gene promoter and association with hyperbilirubinemia."Bioche,. Biophys. Res. Commun.. 292. 492-497 (2002)

J.Sugatani 等人：“UDP-葡萄糖醛酸基转移基因启动子缺陷的鉴定及其与高胆红素血症的关联。”Bioche，。

T.Nakamura et al.: "Relationship between the platelet activating factor acerylhydrolase gene and intractability of ulcerative colitis"Dis. Colon Rectum. 45. 389-393 (2002)

T.Nakamura等：“血小板活化因子乙酰水解酶基因与溃疡性结肠炎难治性的关系”Dis。

J.Sugatani et al.: "The induction of human UDP-glucuronosyltransferase 1A1 medited through a distal enhancer module by flavonoids and xenobiotics."Biochem. Pharmacol.. 67. 989-1000 (2004)

J.Sugatani 等人：“通过类黄酮和异生素通过远端增强子模块介导人 UDP-葡萄糖醛酸基转移酶 1A1 的诱导。”Biochem。