Altered Disposition of Acetaminophen in Nrf2-null and Keap1-knockdown Mice
Altered Disposition of Acetaminophen in Nrf2-null and Keap1-knockdown Mice
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DOI：
10.1093/toxsci/kfp047
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发表时间：
2009-05-01
影响因子：
3.8
通讯作者：
Klaassen, Curtis D.
中科院分区：
文献类型：
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作者：
Reisman, Scott A.;Csanaky, Ivan L.;Klaassen, Curtis D.
对乙酰氨基酚（AA）是一种广泛使用的解热药物，在高剂量下会引起肝毒性。核因子红细胞2相关因子2（Nrf 2）是一种转录因子，通过诱导基因如NAD（P）H：醌氧化还原酶1（Nqo 1）、多药耐药相关蛋白（Mrps）和谷胱甘肽（GSH）合成酶来减轻AA的亲电应激。确定Nrf 2激活是否改变AA、雄性野生型、Nrf 2缺失和Keap 1的生物转化和排泄（Kelch样ECH相关蛋白1）-敲除（Keap 1-kd）小鼠（其具有增加的Nrf 2活化）被给予单次亚毒性剂量的AA（50 mg/kg，iv），之后定量血浆、胆汁和肝脏中的AA及其代谢产物（AA-葡糖苷酸[AA-GLUC]; AA-硫酸盐[AA-SULF]; AA-谷胱甘肽[AA-GSH]）。由于葡萄糖醛酸化活性降低和基底外侧外排转运蛋白Mrp 3的表达降低，Nrf 2基因敲除小鼠血浆中的AA-GLUC浓度降低，肝脏中的AA-GLUC浓度升高。相比之下，Keap 1-kd小鼠的血浆AA-GLUC浓度较高，肝脏AA-GLUC浓度较低，这是由于Mrp 3表达较高。Nrf 2缺失小鼠的葡萄糖醛酸化活性较低，增加了可用于硫酸化的AA比例，导致血浆、胆汁和肝脏中AA-SULF浓度升高。Keap 1-kd小鼠中AA-硫酸化活性降低导致AA-SULF浓度降低。AA-GSH结合物在Nrf 2-null小鼠中增加，在Keap 1-kd小鼠中倾向于降低。此外，Nqo 1，一种能够解毒AA代谢的反应性中间体N-乙酰基-对苯醌亚胺（NAPQI）的酶，在Nrf 2基因敲除小鼠中的活性比野生型低85%，在Keap 1-kd小鼠中的活性比野生型高415%。总之，Nrf 2的缺乏导致AA葡萄糖醛酸化减少，导致NAPQI形成可用的AA增加，以及AA-GLUC通过Mrp 3的外排减少;然而，在Keap 1-kd小鼠中，Nrf 2的激活导致磺基转移酶活性降低，AA-SULF形成减少，以及由于Mrp 3表达增加而导致AA-GLUC消除增强。
Acetaminophen (AA) is a widely used antipyretic drug that causes hepatotoxicity at high doses. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that mitigates electrophilic stress from AA by inducing genes, such as NAD(P)H:quinone oxidoreductase 1 (Nqo1), multidrug resistance-associated proteins (Mrps), and glutathione (GSH) synthesis enzymes. To determine whether Nrf2 activation alters the biotransformation and excretion of AA, male wild-type, Nrf2-null, and Keap1 (Kelch-like ECH-associated protein 1)-knockdown (Keap1-kd) mice (which have increased activation of Nrf2) were administered a single subtoxic dose of AA (50 mg/kg, iv), after which, AA and its metabolites (AA-glucuronide [AA-GLUC]; AA-sulfate [AA-SULF]; AA-glutathione [AA-GSH]) were quantified in plasma, bile, and liver. AA-GLUC concentrations were reduced in plasma and elevated in livers of Nrf2-null mice due to decreased glucuronidation activity and lower expression of the basolateral efflux transporter Mrp3. In contrast, Keap1-kd mice had higher plasma and lower hepatic AA-GLUC concentrations, due to higher Mrp3 expression. Lower glucuronidation activity of Nrf2-null mice increased the proportion of AA available for sulfation, resulting in elevated AA-SULF concentrations in plasma, bile, and liver. Decreased AA-sulfation activity in Keap1-kd mice resulted in lower AA-SULF concentrations. AA-GSH conjugates were increased in Nrf2-null mice and tended to be lower in Keap1-kd mice. Furthermore, Nqo1, an enzyme capable of detoxifying the reactive intermediate of AA metabolism, N-acetyl-p-benzoquinone imine (NAPQI), had 85% lower activity in Nrf2-null mice and 415% higher activity in Keap1-kd mice relative to wild-type. In conclusion, lack of Nrf2 results in decreased AA glucuronidation, leading to increased AA available for NAPQI formation and decreased efflux of AA-GLUC via Mrp3; however, activation of Nrf2, as in Keap1-kd mice, results in decreased sulfotransferase activity, decreased AA-SULF formation, and enhanced elimination of AA-GLUC due to increased expression of Mrp3.