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Metabolism of the anthelmintic drug niclosamide by cytochrome P450 enzymes and UDP-glucuronosyltransferases: metabolite elucidation and main contributions from CYP1A2 and UGT1A1

Danyi Lu,Zhiguo Ma,Tianpeng Zhang,Xingwang Zhang,Baojian Wu

Forsythiaside A Reduces Acetaminophen Hepatotoxic Metabolism by Inhibiting Pregnane X Receptor

Sisi Pu,Yangyang Pan,Zuoyang Wang,Huimin Liu,Jianhui Zhang,Qian Zhang,Meng Wang

Overdose intake of acetaminophen (APAP) causes liver injury involving hepatic drug metabolism and activation of oxidative stress pathways, and forsythiaside A (FA) has hepatoprotective pharmacological activity, but knowledge of the mechanism of FA treatment for APAP liver injury is still lacking the literature. In this study, we investigated the effects of FA on the pregnane X receptor (PXR) by molecular docking and reporter gene assays. In addition, we explored the effects of FA on oxidative stress, endoplasmic reticulum stress (ERS), apoptosis, and hepatic pathology by interfering withPXRin ex vivo and in vivo models. The results showed that FA decreased thePXRprotein expression level and effectively reduced the oxidative stress level in the APAP model. In addition, FA reduced the expression of ERS pathway ProteinkinaseR-likeERkinase (PERK)-translation initiation factor 2 (eIF-2α)-activating transcription factor 4 (ATF4) by inhibitingPXR, and at the same time, decreased the expression of apoptotic proteins C/EBP homologous protein (CHOP), Bax, Caspase 3, and Caspase 7, and elevated the expression of apoptosis-suppressing protein Bcl-2, which ultimately treated the hepatic pathology injury of APAP in mice. The present study confirmed that FA improved APAP metabolism by inhibitingPXR-mediated CYP1A2 and CYP3A11 and alleviated APAP-induced hepatic impairment by inhibiting hepatic oxidative stress, ERS, and apoptosis.

Luteolin is a rare substrate of human catechol-O-methyltransferase favoring a para-methylation

Zhong-Jian Chen,Yan-Qing Dai,Si-Si Kong,Fei-Feng Song,Li-Ping Li,Jian-Feng Ye,Ru-Wei Wang,Su Zeng,Hui Zhou,Hui-Di Jiang

Scope The study aimed to investigate the regioselectivity of methylation of luteolin (3′,4′,5,7-tetrahydroxyflavone) in human in vitro and in vivo. Methods and results Recombinant human catechol- O -methyltransferase (COMT) and human liver S9 were utilized to study the kinetics of meta (3′)- and para (4′)- methylation of luteolin, and urine samples from volunteers after giving a luteolin-containing formulation were collected to determine the ratio of para-/meta-production. The results showed luteolin favored a para-methylation, with a ratio of of para-/meta-production in CL int (1.43 in recombinant human COMT and 1.47 in human liver S9), which was contrary to the known substrates of COMT. However, the result of urine sample assay showed a preference of meta-methylation with a ratio of of para-/meta-production (0.460 ± 0.126). To elucidate the mechanism for different preference of methylation of luteolin in vitro and in vivo, metabolism stability of the meta- and para-methylated luteolin was evaluated in human liver microsomes and recombinant human CYP450s, which revealed that para-methylated luteolin was more easily demethylated by human CYP1A2 and CYP3A4/5 than meta-methylated luteolin. Conclusion Luteolin was a rare substrate of human COMT favoring a para-methylation, but further demethylation by human CYP1A2 and CYP3A4/5 caused a preference of accumulation in meta-methylated luteolin in vivo.

Role of circadian clock in the chronoefficacy and chronotoxicity of clopidogrel

Luyao Ma,Fangjun Yu,Di He,Lianxia Guo,Yu Yang,Wangchun Li,Tianpeng Zhang

Background and purpose The role of CLOCK in regulation of drug chronoefficacy and chronotoxicity remains elusive. Here, we aimed to uncover the impact of CLOCK and dosing time on clopidogrel efficacy and toxicity. Experimental Approach The antiplatelet effect, toxicity and pharmacokinetics experiments were conducted with Clock −/− and wild-type mice after gavage administration of clopidogrel at different circadian time points. The expression levels of drug metabolizing enzymes were determined by qPCR and Western blotting. Transcriptional gene regulation was investigated using luciferase reporter and chromatin immunoprecipitation assays. Key Results The antiplatelet effect and toxicity of clopidogrel in wild-type mice showed a dosing-time dependent variation. Clock ablation reduced the antiplatelet effect of clopidogrel, increased clopidogrel-induced hepatotoxicity, and blunted their rhythms. This was associated with attenuated rhythms of clopidogrel active metabolite (Clop-AM) and clopidogrel, respectively. We further found that Clock regulated the diurnal variation of Clop-AM formation by modulating the rhythmic expression of CYP1A2 and CYP3A11, and altered clopidogrel chronopharmacokinetics by circadian regulation of CES1D expression. Mechanistic studies revealed that CLOCK activated Cyp1a2 and Ces1d transcription by directly binding to the E-box elements in their promoters, and promoted Cyp3a11 transcription through enhancing the transactivation activity of DBP and TEF. Conclusion and implication CLOCK regulates the diurnal rhythmicity in clopidogrel efficacy and toxicity through regulation of CYP1A2, CYP3A11 and CES1D expression. The findings may contribute to the optimization of dosing schedule for clopidogrel, and deepen understanding of the connection between the circadian clock and chronopharmacology.

Type 2 diabetes mellitus decreases systemic exposure of clopidogrel active metabolite through upregulation of P-glycoprotein in rats

Hongwei Yao,Jingkai Gu,Yuqin Shan,Yani Wang,Xue Chen,Dong Sun,Yingjie Guo

Patients with diabetic mellitus tend to have a poor response to clopidogrel (Clop) due to reduced generation of active metabolite (Clop-AM). However, the underlying mechanism is not elucidated. A type 2 diabetic mellitus (T2DM) rat model was established by combining high-fat diet feeding and low-dose streptozotocin (STZ) injection. The reduced Clop-AM exposure was observed in T2DM rats after oral administration of Clop. However, in vitro liver microsomes incubated with Clop exhibited increased Clop-AM levels in T2DM rats due to a significant decrease in carboxylesterase (CES)1 expression and activity and a significant increase in the expression or activity of CYP1A2 and CYP3A . Interestingly, different from oral administration, the significantly increased C max of Clop-AM was observed in T2DM rats after intravenous injection, with no difference in AUC 0-t and t 1/2 values between the two strains. Meanwhile, in situ single -pass intestinal perfusion study showed lower absorption rate constant ( K a) and effective apparent permeability values ( P eff ) of Clop in T2DM rats than in control rats. It is explained by the increased expression or function of P-glycoprotein (P-gp) and pregnane X receptor (PXR) in duodenum and jejunum of T2DM rats. Moreover, the decreased Clop-AM level in T2DM rats was eliminated by the pretreatment of cyclosporin A , a P-gp inhibitor. It suggests that intestinal absorption, not hepatic metabolism is responsible for the reduced Clop-AM exposure in T2DM rats. P-gp might be the key factor causing the reduction of Clop absorption, consequently making less Clop available for Clop-AM formation.

In vitro and In Vivo Drug Metabolism Analysis of BPI-460372 - A Covalent TEAD1/3/4 Inhibitor

Xiaoyun Liu,Dafang Zhong,Chongzhuang Tang,Xiaofeng Xu,Hong Lan,Xingxing Diao

Background BPI-460372 is an orally available, covalent, irreversible small molecule inhibitor of the transcriptional enhanced associate domain (TEAD) 1/3/4, which is currently in clinical development for the treatment of cancers with Hippo pathway alterations. Objectives This study aimed to determine the cytochrome P450 (CYP) phenotyping, metabolic stability, and in vitro and in vivo metabolic profile of BPI-460372. Methods The CYP phenotyping and metabolic stability were assessed by measuring the depletion of substrate. The metabolic profile in hepatocytes and rat and dog plasma was analyzed using ultra-high-performance liquid chromatography combined with Orbitrap tandem mass spectrometry (UHPLC-Orbitrap-HRMS). Results BPI-460372 was mainly metabolized by CYP2D6, CYP3A4, and CYP1A2. BPI-460372 exhibited low clearance in human, monkey, and rat hepatocytes, while moderate clearance in dog and mouse hepatocytes. A total of 10 metabolites were identified in five species of hepatocytes, and no human-unique metabolite was detected. In rat plasma and dog plasma, the primary metabolites were M407 (BPI-460430) and M423 (BPI-460456), respectively. The two metabolites were quantitatively determined in rat and dog plasma in pharmacokinetic and toxicological studies. The major metabolic site was 2-fluoro-acrylamide, and major metabolic pathways in hepatocytes, and rat and dog plasma involved oxidative defluorination, hydration, glutathione (GSH) conjugation, hydrolysis, cysteine conjugation, and N-acetyl cysteine conjugation. β-lyase pathway contributed to the metabolism of BPI-460372 in rats to a certain degree. Conclusion This study elucidated the metabolism of BPI-460372 and provided a basis for pharmacokinetic and toxicological species selection, human pharmacokinetics prediction, and assessment of clinical co-administration limitations and possible metabolic pathways in humans.

Effects of infection of MRSA on the expression and activity of renal cytochrome P450s in mice

Nana Long,Huaqiao Tang,Lin Lin,Jianlong Li,Lijuan Guo,Fenghui Sun,Min Dai

Methicillin-resistant Staphylococcus aureus (MRSA) leads to serious infections, but it is not known whether it changes the expression of kidney drug metabolizing enzymes during infection. The mice were infected with different doses of MRSA and the oxidative stress and inflammation levels in the kidney were examined. The mRNA expression and activity of cytochrome P450 enzyme was analysed. Mice infected with high levels of MRSA showed a decrease in renal antioxidant capability and an elevated level of oxidative metabolites, which was accompanied by the release of inflammatory cytokines. The levels of interleukin 1β, tumour necrosis factor alpha, and macrophage inflammatory protein-1α were significantly increased along with the levels of nitric oxide and malondialdehyde. On day 7, mRNA expression of Cyp1a2, 2d22, and 3a11 were decreased by the high level of MRSA, but the low level of MRSA increased their expressions. Cyp2e1 mRNA expression was increased by MRSA in the kidney of mice. High dose of MRSA infection increased the oxidative stress and inflammatory response in mouse kidney, leading to the decrease in the expression of renal drug-metabolizing enzymes and no recovery within 7 days.

Aryl Hydrocarbon Receptor as a Target for Lycopene Preventing DEHP-Induced Spermatogenic Disorders

Yi Zhao,Jia Lin,Milton Talukder,Shi-Yong Zhu,Mu-Zi Li,Hao-Ran Wang,Jin-Long Li

Di(2-ethylhexyl)phthalate (DEHP) is widely used as a plasticizer to improve product flexibility and workability. Lycopene (LYC) is a natural compound and has promising preventive potentials, especially antireproductive toxicity, but the specific underlying mechanism is yet to be fully defined. Our study investigated the effect of LYC on DEHP-induced spermatogenesis disorders. Male ICR mice were treated with DEHP (500 or 1000 mg/kg BW/day) and/or LYC (5 mg/kg BW/day) for 28 days. Our results indicated that LYC could relieve the DEHP-induced injury of seminiferous tubules and spermatogenic cells, swelling of endoplasmic reticulum (ER), and an increase of mitochondria. LYC prevented increased levels of nuclear damage to DNA and the deformity rate and decreased values of sperm motility, number, and density. Moreover, LYC treatment decreased DEHP-induced nuclear accumulation of aryl hydrocarbon receptor (AHR) and AHR nuclear translocator (ARNT), and the expressions of their downstream target genes such as cytochrome P450-dependent monooxygenases (CYP) 1A1, 1A2, and 1B1 were markedly reduced to normal in the LYC treatment group. Our study showed that LYC can prevent DEHP-induced spermatogenic disorders via an AHR/ARNT signaling system. This study provided new evidence of AHR as a target for LYC, which can prevent DEHP-induced toxicity.

Lycopene Preventing DEHP-Induced Renal Cell Damage Is Targeted by Aryl Hydrocarbon Receptor

Mu-Zi Li,Yi Zhao,Hao-Ran Wang,Milton Talukder,Jin-Long Li

Di (2-ethylhexyl) phthalate (DEHP) is an environmentally persistent and bioaccumulative plasticizer. Accumulation of DEHP in the body can eventually cause kidney damage. As a type of natural carotenoid, lycopene (LYC) has a potential protective effect on renal cells, but the protective mechanism has not yet been elucidated. The major goal of this study was to see how effective LYC was at treating DEHP-induced nephrotoxicity in mice. ICR mice were treated with DEHP (500 mg/kg BW/day or 1000 mg/kg BW/day) or LYC (5 mg/kg BW/day) for 28 days. Through histopathology and ultrastructure, we found that LYC attenuated DEHP-induced renal tubular cell and glomerular damage. LYC relieved DEHP-induced kidney injury evidenced by lower levels of blood urea nitrogen (Bun), creatinine (Cre), and uric acid (Uric). Meanwhile, the reduced expression of kidney injury molecule-1 (Kim-1) also supported it. Notably, LYC can alleviate the activity or content of cytochrome P450 system (CYP450s) interfered with by DEHP. In addition, LYC treatment reduced nuclear accumulation of DEHP-induced aromatic hydrocarbon receptor (AhR) and AhR nuclear transporter (Arnt), and its downstream target genes such as cytochrome P450-dependent monooxygenase (CYP) 1A1, 1A2, and 1B1 expression significantly decreased to normal in the LYC treatment group. In summary, LYC can mediate the AhR/Arnt signaling system to prevent kidney toxicity in mice caused by DEHP exposure.