Characterization of the structural determinants required for potent mechanism-based inhibition of human cytochrome P450 1A1 by cannabidiol

We previously demonstrated that cannabidiol (CBD) was a potent mechanism-based inhibitor of human cytochrome P450 1A1 (CYP1A1). However, the moiety of CBD that contributes to the potent mechanism-based inhibition of human CYP1A1 remains unknown. Thus, the effects of compounds structurally related to CBD on CYP1A1 activity were examined with recombinant human CYP1A1 in order to characterize the structural requirements for potent inactivation by CBD. When preincubated in the presence of NADPH for 20 min, olivetol, which corresponds to the pentylresorcinol moiety of CBD, enhanced the inhibition of the 7-ethoxyresorufin O-deethylase activity of CYP1A1. In contrast, d-limonene, which corresponds to the terpene moiety of CBD, failed to inhibit CYP1A1 activity in a metabolism-dependent manner. Pentylbenzene, which lacks two free phenolic hydroxyl groups, also did not enhance CYP1A1 inhibition. On the other hand, preincubation of the CBD-2′-monomethyl ether (CBDM) and CBD-2′,6′-dimethyl ether (CBDD) enhanced the inhibition of CYP1A1 activity. Inhibition by cannabidivarin (CBDV), which possessed a propyl side chain, was strongly potentiated by its preincubation. Orcinol, which has a methyl group, augmented CYP1A1 inhibition, whereas its derivative without an alkyl side chain, resorcinol, did not exhibit any metabolism-dependent inhibition. The preincubation of CBD-hydroxyquinone did not markedly enhance CYP1A1 inhibition. We further confirmed that olivetol, CBDM, CBDD, CBDV, and orcinol, as well as CBD (kinact = 0.215 min−1), inactivated CYP1A1 activity; their kinact values were 0.154, 0.0638, 0.0643, 0.226, and 0.0353 min−1, respectively. These results suggest that the methylresorcinol structure in CBD may have structurally important roles in the inactivation of CYP1A1.ArticleCHEMICO-BIOLOGICAL INTERACTIONS.215:62-68(2014)journal articl

Differentiation of Monkey Embryonic Stem Cells to Hepatocytes by Feeder-Free Dispersion Culture and Expression Analyses of Cytochrome P450 Enzymes Responsible for Drug Metabolism

信州大学博士（医学）・学位論文・平成25年2月13日授与（乙第1155号）・丸山 順也We reported previously that monkey embryonic stem cells (ESCs) were differentiated into hepatocytes by formation of embryoid bodies (EBs). However, this EB formation method is not always efficient for assays using a large number of samples simultaneously. A dispersion culture system, one of the differentiation methods without EB formation, is able to more efficiently provide a large number of feeder-free undifferentiated cells. A previous study demonstrated the effectiveness of the Rho-associated kinase inhibitor Y-27632 for feeder-free dispersion culture and induction of differentiation of monkey ESCs into neural cells. In the present study, the induction of differentiation of cynomolgus monkey ESCs (cmESCs) into hepatocytes was performed by the dispersion culture method, and the expression and drug inducibility of cytochrome P450 (CYP) enzymes in these hepatocytes were examined. The cmESCs were successfully differentiated into hepatocytes under feeder-free dispersion culture conditions supplemented with Y-27632. The hepatocytes differentiated from cmESCs expressed the mRNAs for three hepatocyte marker genes (alpha-fetoprotein, albumin, CYP7A1) and several CYP enzymes, as measured by real-time polymerase chain reaction. In particular, the basal expression of cmCYP3A4 (3A8) in these hepatocytes was detected at mRNA and enzyme activity (testosterone 6 beta-hydroxylation) levels. Furthermore, the expression and activity of cmCYP3A4 (3A8) were significantly upregulated by rifampicin. These results indicated the effectiveness of Y-27632 supplementation for feeder-free dispersed culture and induction of differentiation into hepatocytes, and the expression of functional CYP enzyme(s) in cmESC-derived hepatic cells.ArticleBIOLOGICAL & PHARMACEUTICAL BULLETIN. 36(2) 292-298 (2013)journal articl

<i>In Vitro</i> Inhibition of CYP2C9-Mediated Warfarin 7-Hydroxylation by Iguratimod

Iguratimod is a novel disease-modifying antirheumatic drug. A blue letter (safety advisory) for drug interaction between iguratimod and warfarin was issued by the Ministry of Health, Labour and Welfare of Japan in May 2013. Iguratimod may affect warfarin metabolism catalyzed by CYP. However, it is not clear whether iguratimod inhibits warfarin oxidation. This study was performed to investigate the effects of iguratimod on warfarin 7-hydroxylation with human liver microsomes (HLMs) and recombinant CYP enzymes. Iguratimod concentration-dependently inhibited R,S-warfarin 7-hydroxylase activity of HLMs with an IC50 value of 15.2 µM. The inhibitory effect was examined with S-warfarin and R-warfarin to determine which enantiomer was more potently inhibited by iguratimod. Iguratimod potently inhibited the S-warfarin 7-hydroxylase activity of HLMs with an IC50 value of 14.1 µM, but showed only slight inhibition of R-warfarin 7-hydroxylation. Furthermore, iguratimod inhibited the S-warfarin 7-hydroxylase activity of recombinant CYP2C9.1 (rCYP2C9.1) and rCYP2C9.3 in a concentration-dependent manner with IC50 values of 10.8 and 20.1 µM, respectively. Kinetic analysis of the inhibition of S-warfarin 7-hydroxylation by iguratimod indicated competitive-type inhibition for HLMs and rCYP2C9.1 but mixed-type inhibition for rCYP2C9.3. The Ki values for HLMs, rCYP2C9.1, and rCYP2C9.3 were 6.74, 4.23, and 14.2 µM, respectively. Iguratimod did not exert metabolism-dependent inhibition of S-warfarin 7-hydroxylation. These results indicated that iguratimod is a potent direct inhibitor of CYP2C9-mediated warfarin 7-hydroxylation and that its inhibitory effect on CYP2C9.1 was more sensitive than that on CYP2C9.3.ArticleBIOLOGICAL & PHARMACEUTICAL BULLETIN.38(3):441-447(2015)journal articl

Cannabidiol induces expression of human cytochrome P450 1A1 that is possibly mediated through aryl hydrocarbon receptor signaling in HepG2 cells

AimsWe herein investigated the inducibility of cytochrome P450 1A1 (CYP1A1) by Δ9-tetrahydrocannabinol, cannabidiol (CBD), and cannabinol, three major phytocannabinoids, using human hepatoma HepG2 cells.Main methodsThe expression of CYP1A1 and the aryl hydrocarbon receptor (AhR) was measured by a quantitative real-time polymerase chain reaction and/or Western blotting.Key findingsΔ9-Tetrahydrocannabinol and CBD concentration-dependently induced the expression of CYP1A1 mRNA, whereas cannabinol showed little or no induction. Among the phytocannabinoids tested, CBD was the most potent inducer of CYP1A1 expression. The induction of CYP1A1 expression by CBD was significantly attenuated by the knockdown of AhR expression with AhR small interfering RNAs. The role of protein tyrosine kinases (PTKs) in the CBD-mediated induction of CYP1A1 was then examined using herbimycin A, a PTK inhibitor. The upregulation of CYP1A1 by CBD was significantly suppressed by herbimycin A as was the induction by omeprazole but not 3-methylcholanthrene. The inducibility of CYP1A1 by CBD-related compounds was examined to clarify the structural requirements for CBD-mediated CYP1A1 induction. Olivetol, which corresponds to the pentylresorcinol moiety of CBD, significantly induced the expression of CYP1A1, whereas d-limonene, CBD-2′-monomethyl ether, and CBD-2′,6′-dimethyl ether did not.SignificanceThese results showed that CBD may have induced human CYP1A1 expression through the activation of PTK-dependent AhR signaling, in which two phenolic hydroxyl groups in the pentylresorcinol moiety of CBD may play structurally important roles.ArticleLIFE SCIENCES.136:87-93(2015)journal articl

Stereospecific and Regioselective Hydrolysis of Cannabinoid Esters by ES46.5K, an Esterase from Mouse Hepatic Microsomes, and Its Differences from Carboxylesterases of Rabbit and Porcine Liver

The properties of ES46.5K, an esterase from mouse hepatic microsomes, were compared with those of carboxylesterases from rabbit and porcine liver. The inhibitory profile with a serine hydrolase inhibitor (bis-p-nitrophenylphosphate) and detergents (sodium dodecylsulfate, Emulgen 911) was different between ES46.5K and the carboxylesterases. Bis-p-nitrophenylphosphate (0.1 mM) markedly inhibited the catalytic activity of the carboxylesterases but not that of ES46.5K. Emulgen 911 (0.05—0.25%) inhibited the catalytic activity of the carboxylesterases, whereas the detergent conversely stimulated that of ES46.5K by 150%. The two carboxylesterases catalyzed the hydrolysis of acetate esters of tetrahydrocannabinol (THC) analogues with different side chain lengths (C1—C5), although ES46.5K showed marginal activity only against the acetate of Δ8-tetrahydrocannabiorcol, a methyl side chain derivative of Δ8-THC. ES46.5K hydrolyzed cannabinoid esters stereospecifically and regioselectively. The esterase hydrolyzed 8α-acetoxy-Δ9-tetrahydrocannabinol (8α-acetoxy-Δ9-THC, 5.62 nmol/min/mg protein), while the enzyme did not hydrolyze 8β-acetoxy-Δ9-THC, 7α-acetoxy-, and 7β-acetoxy-Δ8-THC at all. In contrast, the carboxylesterases from rabbit and porcine liver hydrolyzed 8β-acetoxy-Δ9-THC efficiently but not 8α-acetoxy-Δ9-THC. ES46.5K hydrolyzed side chain acetoxy derivatives of Δ8-THC at the 3′- and 4′-positions, and a methyl ester of 5′-nor-Δ8-THC-4′-oic acid. The enzyme, however, could not hydrolyze methyl esters of Δ8- and Δ9-THC-11-oic acid, while both carboxylesterases hydrolyzed side chain acetoxy derivatives of Δ8-THC and three methyl esters of THC-oic acids. These differences in stereospecificity and regioselectivity between ES46.5K and carboxylesterases suggest that the configurations of important amino acids for the catalytic activities of these enzymes are different from each other

Differentiation of Monkey Embryonic Stem Cells to Hepatocytes by Feeder-Free Dispersion Culture and Expression Analyses of Cytochrome P450 Enzymes Responsible for Drug Metabolism

信州大学博士（医学）・学位論文・平成25年2月13日授与（乙第1155号）・丸山 順也We reported previously that monkey embryonic stem cells (ESCs) were differentiated into hepatocytes by formation of embryoid bodies (EBs). However, this EB formation method is not always efficient for assays using a large number of samples simultaneously. A dispersion culture system, one of the differentiation methods without EB formation, is able to more efficiently provide a large number of feeder-free undifferentiated cells. A previous study demonstrated the effectiveness of the Rho-associated kinase inhibitor Y-27632 for feeder-free dispersion culture and induction of differentiation of monkey ESCs into neural cells. In the present study, the induction of differentiation of cynomolgus monkey ESCs (cmESCs) into hepatocytes was performed by the dispersion culture method, and the expression and drug inducibility of cytochrome P450 (CYP) enzymes in these hepatocytes were examined. The cmESCs were successfully differentiated into hepatocytes under feeder-free dispersion culture conditions supplemented with Y-27632. The hepatocytes differentiated from cmESCs expressed the mRNAs for three hepatocyte marker genes (alpha-fetoprotein, albumin, CYP7A1) and several CYP enzymes, as measured by real-time polymerase chain reaction. In particular, the basal expression of cmCYP3A4 (3A8) in these hepatocytes was detected at mRNA and enzyme activity (testosterone 6 beta-hydroxylation) levels. Furthermore, the expression and activity of cmCYP3A4 (3A8) were significantly upregulated by rifampicin. These results indicated the effectiveness of Y-27632 supplementation for feeder-free dispersed culture and induction of differentiation into hepatocytes, and the expression of functional CYP enzyme(s) in cmESC-derived hepatic cells.ArticleBIOLOGICAL & PHARMACEUTICAL BULLETIN. 36(2) 292-298 (2013)journal articl