Glucuronidation of drugs in humanized <i><scp>UDP</scp>‐glucuronosyltransferase 1</i> mice: Similarity with glucuronidation in human liver microsomes

Kutsuno, Yuki; Sumida, Kyohei; Itoh, Tomoo; Tukey, Robert H.; Fujiwara, Ryoichi

doi:10.1002/prp2.2

Cited by 24 publications

(21 citation statements)

References 37 publications

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“…Thus, humanized mice offer a better animal model to predict the human drug metabolism and understand the underlying mechanisms. In our recent study, hUGT1 mice showed glucuronidation activity of furosemide, naproxen, imipramine, and trifluoperazine that was comparable to that of humans (Kutsuno et al, 2013). In this study, we investigated the glucuronidation activity of etodolac, diclofenac, and ibuprofen metabolized by UGTs.…”

Section: Discussionmentioning

confidence: 94%

Glucuronidation of Drugs and Drug-Induced Toxicity in HumanizedUDP-Glucuronosyltransferase 1Mice

et al. 2014

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UDP-glucuronosyltransferases (UGTs) are phase II drug-metabolizing enzymes that catalyze glucuronidation of various drugs. Although experimental rodents are used in preclinical studies to predict glucuronidation and toxicity of drugs in humans, species differences in glucuronidation and drug-induced toxicity have been reported. Humanized UGT1 mice in which the original Ugt1 locus was disrupted and replaced with the human UGT1 locus (hUGT1 mice) were recently developed. In this study, acyl-glucuronidations of etodolac, diclofenac, and ibuprofen in liver microsomes of hUGT1 mice were examined and compared with those of humans and regular mice. The kinetics of etodolac, diclofenac, and ibuprofen acyl-glucuronidation in hUGT1 mice were almost comparable to those in humans, rather than in mice. We further investigated the hepatotoxicity of ibuprofen in hUGT1 mice and regular mice by measuring serum alanine amino transferase (ALT) levels. Because ALT levels were increased at 6 hours after dosing in hUGT1 mice and at 24 hours after dosing in regular mice, the onset pattern of ibuprofen-induced liver toxicity in hUGT1 mice was different from that in regular mice. These data suggest that hUGT1 mice can be valuable tools for understanding glucuronidations of drugs and druginduced toxicity in humans.

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Section: Discussionmentioning

confidence: 94%

Glucuronidation of Drugs and Drug-Induced Toxicity in HumanizedUDP-Glucuronosyltransferase 1Mice

et al. 2014

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“…After centrifugation at the top speed for 10 min, the supernatant was analyzed by HPLC. Substrate inhibition kinetics were analyzed using a previously reported equation (Kutsuno et al, 2013), where K si is the constant describing the substrate inhibition interaction.…”

Section: Enzyme Assaysmentioning

confidence: 99%

S5H/DMR6 Encodes a Salicylic Acid 5-Hydroxylase That Fine-Tunes Salicylic Acid Homeostasis

et al. 2017

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The phytohormone salicylic acid (SA) plays essential roles in biotic and abiotic responses, plant development, and leaf senescence. 2,5-Dihydroxybenzoic acid (2,5-DHBA or gentisic acid) is one of the most commonly occurring aromatic acids in green plants and is assumed to be generated from SA, but the enzymes involved in its production remain obscure. DMR6 (Downy Mildew Resistant6; At5g24530) has been proven essential in plant immunity of Arabidopsis (Arabidopsis thaliana), but its biochemical properties are not well understood. Here, we report the discovery and functional characterization of DMR6 as a salicylic acid 5-hydroxylase (S5H) that catalyzes the formation of 2,5-DHBA by hydroxylating SA at the C5 position of its phenyl ring in Arabidopsis. S5H/DMR6 specifically converts SA to 2,5-DHBA in vitro and displays higher catalytic efficiency (K cat /K m = 4. ) for SA. Interestingly, S5H/DMR6 displays a substrate inhibition property that may enable automatic control of its enzyme activities. The s5h mutant and s5hs3h double mutant overaccumulate SA and display phenotypes such as a smaller growth size, early senescence, and a loss of susceptibility to Pseudomonas syringae pv tomato DC3000. S5H/DMR6 is sensitively induced by SA/pathogen treatment and is expressed widely from young seedlings to senescing plants, whereas S3H is more specifically expressed at the mature and senescing stages. Collectively, our results disclose the identity of the enzyme required for 2,5-DHBA formation and reveal a mechanism by which plants fine-tune SA homeostasis by mediating SA 5-hydroxylation.

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“…The highly polar glucuronide conjugate generally decreases the bioactivity of the substrate and increases its water solubility, facilitating excretion through bile or urine. Glucuronidation is important in the metabolism of endogenous wastes and a wide range of drugs, including many chemotherapeutics, nonsteroidal anti-inflammatory drugs, and opioids, and in protecting against harmful environmental agents such as bisphenol A (BPA) and benzo-[a]-pyrene (Fang et al, 2002;Hanioka et al, 2008;Kutsuno et al, 2013). Based on evolutionary divergence and homology, mammalian UGTs have been organized into two major families: The UGT1 and UGT2 families.…”

Section: Introductionmentioning

confidence: 99%

Xenobiotic Metabolism in Mice Lacking the UDP-Glucuronosyltransferase 2 Family

et al. 2015

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UDP-Glucuronosyltransferases (UGTs) conjugate a glucuronyl group from glucuronic acid to a wide range of lipophilic substrates to form a hydrophilic glucuronide conjugate. The glucuronide generally has decreased bioactivity and increased water solubility to facilitate excretion. Glucuronidation represents an important detoxification pathway for both endogenous waste products and xenobiotics, including drugs and harmful industrial chemicals. Two clinically significant families of UGT enzymes are present in mammals: UGT1s and UGT2s. Although the two families are distinct in gene structure, studies using recombinant enzymes have shown considerable overlap in their ability to glucuronidate many substrates, often obscuring the relative importance of the two families in the clearance of particular substrates in vivo. To address this limitation, we have generated a mouse line, termed DUgt2, in which the entire Ugt2 gene family, extending over 609 kilobase pairs, is excised. This mouse line provides a means to determine the contributions of the two UGT families in vivo. We demonstrate the utility of these animals by defining for the first time the in vivo contributions of the UGT1 and UGT2 families to glucuronidation of the environmental estrogenic agent bisphenol A (BPA). The highest activity toward this chemical is reported for human and rodent UGT2 enzymes. Surprisingly, our studies using the DUgt2 mice demonstrate that, while both UGT1 and UGT2 isoforms can conjugate BPA, clearance is largely dependent on UGT1s.

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Glucuronidation of drugs in humanized UDP‐glucuronosyltransferase 1 mice: Similarity with glucuronidation in human liver microsomes

Cited by 24 publications

References 37 publications

Glucuronidation of Drugs and Drug-Induced Toxicity in HumanizedUDP-Glucuronosyltransferase 1Mice

Glucuronidation of Drugs and Drug-Induced Toxicity in HumanizedUDP-Glucuronosyltransferase 1Mice

S5H/DMR6 Encodes a Salicylic Acid 5-Hydroxylase That Fine-Tunes Salicylic Acid Homeostasis

Xenobiotic Metabolism in Mice Lacking the UDP-Glucuronosyltransferase 2 Family

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