Identification of the N-terminal residues responsible for the differential microdomain localization of CYP1A1 and CYP1A2.

The endoplasmic reticulum (ER) is organized into ordered regions enriched in cholesterol and sphingomyelin, and disordered microdomains characterized by more fluidity. Rabbit CYP1A1 and CYP1A2 localize into disordered and ordered microdomains, respectively. Previously, a CYP1A2 chimera containing the first 109 amino acids of CYP1A1 showed altered microdomain localization. The goal of this study was to identify specific residues responsible for CYP1A microdomain localization. Thus, CYP1A2 chimeras containing substitutions from homologous regions of CYP1A1 were expressed in HEK 293T/17 cells, and the localization was examined after solubilization with Brij 98. A CYP1A2 mutant with the three amino acids from CYP1A1 (VAG) at positions 27-29 of CYP1A2 was generated that showed a distribution pattern similar to those of CYP1A1/1A2 chimeras containing both the first 109 amino acids and the first 31 amino acids of CYP1A1 followed by remaining amino acids of CYP1A2. Similarly, the reciprocal substitution of three amino acids from CYP1A2 (AVR) into CYP1A1 resulted in a partial redistribution of the chimera into ordered microdomains. Molecular dynamic simulations indicate that the positive charges of the CYP1A1 and CYP1A2 linker regions between the N-termini and catalytic domains resulted in different depths of immersion of the N-termini in the membrane. The overlap of the distribution of positively charged residues in CYP1A2 (AVR) and negatively charged phospholipids was higher in the ordered than disordered microdomain. These findings identify three residues in the CYP1A N-terminus as a novel microdomain-targeting motif of the P450s and provide a mechanistic explanation for the differential microdomain localization of CYP1A.

CYP1A inhibitors: Recent progress, current challenges, and future perspectives.

Mammalian cytochrome P450 1A (CYP1A) are key phase I xenobiotic-metabolizing enzymes that play a distinctive role in metabolic activation or metabolic clearance of a variety of procarcinogens, drugs, and endogenous substances. Human CYP1A subfamily contains two members (hCYP1A1 and hCYP1A2), which are known to catalyze the oxidative activation of some environmental procarcinogens into carcinogenic species. Increasing evidence has demonstrated that CYP1A inhibitor therapies are promising strategies for cancer chemoprevention or overcoming CYP1A-associated drug toxicity and resistance. Herein, we reviewed recent advances in the discovery and characterization of hCYP1A inhibitors, from the discovery approaches to structural features and biomedical applications of hCYP1A inhibitors. The inhibition potentials, inhibition modes, and inhibition constants of all reported hCYP1A inhibitors are comprehensively summarized. Meanwhile, the structural features and structure-activity relationships of different classes of hCYP1A1 and hCYP1A2 inhibitors are analyzed and discussed in depth. Furthermore, the major challenges and future directions for this field are presented and highlighted. Collectively, the information and knowledge presented here will strongly facilitate the researchers to discover and develop more efficacious CYP1A inhibitors for specific purposes, such as chemo-preventive agents or as tool molecules in hCYP1A-related fundamental studies.

METTL3-induced circ_0008345 contributes to the progression of colorectal cancer via the microRNA-182-5p/CYP1A2 pathway.

BACKGROUND: Circular RNA (circRNAs) have been found to play major roles in the progression of colorectal cancer (CRC). However, the functions of circ_0008345 (transcribed by PTK2) in regulating CRC development remain undefined. In this study, we aimed to explore the roles and underlying mechanisms of circ_0008345 in CRC. METHODS: RNase R-treated total cellular RNA was used to verify the circular structure of circ_0008345, and a subcellular fractionation assay was performed to detect the subcellular localization of circ_0008345. RNA pull-down and dual-luciferase assays were used to verify the binding relation between microRNA (miR)-182-5p and circ_0008345 and/or CYP1A2. Colony formation assay, EdU, and Transwell assays were performed to detect the biological behavior of CRC cells in vitro, and CRC cells were injected into mice to observe the tumor formation. m6A immunoprecipitation was used to detect the m6A modification of circ_0008345 in CRC cells. RESULTS: Circ_0008345, upregulated in CRC tissues and cells, was mainly present in the cytoplasm. Circ_0008345 bound to miR-182-5p, and miR-182-5p targeted CYP1A2, an oncogene in CRC. The colony formation, mobility, EdU-positive cell rate in vitro, and tumor growth in mice were inhibited after the knockdown of circ_0008345. However, the suppressing effects of sh-circ_0008345 on CRC and CYP1A2 expression were significantly reversed after further knockdown of miR-182-5p. METTL3 was the m6A modifier mediating circ_0008345 expression, and the suppression of METTL3 reduced the expression of circ_0008345. CONCLUSIONS: METTL3-dependent m6A methylation upregulated circ_0008345, which blocked the inhibitory effect of miR-182-5p on CYP1A2, thereby exacerbating the malignant phenotype of CRC cells.

Association between CYP1A2 gene variants -163 C/A (rs762551) and -3860 G/A (rs2069514) and bladder cancer susceptibility.

BACKGROUND: Bladder cancer (BLCA) poses a significant global health challenge due to its high incidence, poor prognosis, and limited treatment options. AIMS AND OBJECTIVES: This study aims to investigate the association between two specific polymorphisms, CYP1A2-163 C/A and CYP1A2-3860G/A, within the Cytochrome P450 1A2 (CYP1A2) gene and susceptibility to BLCA. METHODS: The study employed a case-control design, genotyping 340 individuals using Polymerase Chain Reaction-High-Resolution Melting Curve (PCR-HRM). Various genetic models were applied to evaluate allele and genotype frequencies. Genetic linkage analysis was facilitated using R packages. RESULTS: The study reveals a significant association with the - 163 C/A allele, particularly in the additive model. Odds ratio (OR) analysis links CYP1A2-163 C/A (rs762551) and CYP1A2-3860G/A(rs2069514) polymorphisms to BLCA susceptibility. The rs762551 C/A genotype is prevalent in 55% of BLCA cases and exhibits an OR of 2.21. The A/A genotype has an OR of 1.54. Regarding CYP1A2-3860G/A, the G/A genotype has an OR of 1.54, and the A/A genotype has an OR of 2.08. Haplotype analysis shows a predominant C-C haplotype at 38.2%, followed by a C-A haplotype at 54.7%, and a less frequent A-A haplotype at 7.1%. This study underscores associations between CYP1A2 gene variants, particularly rs762551 (CYP1A2-163 C/A), and an increased susceptibility to BLCA. Haplotype analysis of 340 individuals reveals a predominant C-C haplotype at 38.2%, followed by a C-A haplotype at 54.7%, and a less frequent A-A haplotype at 7.1%. CONCLUSION: In conclusion, the - 163 C/A allele, C/A genotype of rs762551, and G/A genotype of rs2069514 emerge as potential genetic markers associated with elevated BLCA risk.

Caffeine Consumption and Interaction with ADORA2A, CYP1A2 and NOS1 Variants Do Not Influence Age at Onset of Machado-Joseph Disease.

BACKGROUND: The age at onset (AO) of Machado-Joseph disease (SCA3/MJD), a disorder due to an expanded CAG repeat (CAGexp) in ATXN3, is quite variable and the role of environmental factors is still unknown. Caffeine was associated with protective effects against other neurodegenerative diseases, and against SCA3/MJD in transgenic mouse models. We aimed to evaluate whether caffeine consumption and its interaction with variants of caffeine signaling/metabolization genes impact the AO of this disease. METHODS: a questionnaire on caffeine consumption was applied to adult patients and unrelated controls living in Rio Grande do Sul, Brazil. AO and CAGexp were previously determined. SNPs rs5751876 (ADORA2A), rs2298383 (ADORA2A), rs762551 (CYP1A2) and rs478597 (NOS1) were genotyped. AO of subgroups were compared, adjusting the CAGexp to 75 repeats (p < 0.05). RESULTS: 171/179 cases and 98/100 controls consumed caffeine. Cases with high and low caffeine consumption (more or less than 314.5 mg of caffeine/day) had mean (SD) AO of 35.05 (11.44) and 35.43 (10.08) years (p = 0.40). The mean (SD) AO of the subgroups produced by the presence or absence of caffeine-enhancing alleles in ADORA2A (T allele at rs5751876 and rs2298383), CYP1A2 (C allele) and NOS1 (C allele) were all similar (p between 0.069 and 0.516). DISCUSSION: Caffeine consumption was not related to changes in the AO of SCA3/MJD, either alone or in interaction with protective genotypes at ADORA2A, CYP1A2 and NOS1.

Effect of lemborexant on pharmacokinetics of clozapine: A potential drug-drug interaction mediated by time-dependent inhibition of CYP3A4.

Clozapine (CLZ) is extensively used for treatment-resistant schizophrenia (TRS) with caution to avoid serious adverse events such as agranulocytosis and drug-drug interactions (DDIs). In the current report, we present a case of a 35-year-old male non-smoking TRS patient whose steady-state plasma trough concentrations (Ctrough ) of CLZ and its active metabolite, N-desmethylclozapine (NDMC), were significantly increased after initiating oral administration of lemborexant (LEM), a dual orexin receptor antagonist, for the treatment of insomnia. The patient experienced oversedation with sleepiness and fatigue while maintaining high levels of Ctrough of CLZ. The increased concentrations of CLZ returned to normal ranges after the discontinuation of LEM dosing, implying a pharmacokinetic DDI between CLZ and LEM. To gain insight into possible mechanisms, we performed in vitro assays of CYP1A2- and CYP3A4-mediated CLZ metabolism by measuring the formations of NDMC and clozapine N-oxide (CNO). In accordance with previous studies, the incubation of CLZ with each enzyme resulted in the production of both metabolites. LEM had only a weak inhibitory effect on CYP1A2- and CYP3A4-mediated CLZ metabolism. However, the preincubation of LEM with CYP3A4 in the presence of NADPH showed a significant enhancement of inhibitory effects on CLZ metabolism with IC50 values for the formations of CNO and NDMC of 2.8 µM and 4.1 µM, respectively, suggesting that LEM exerts as a potent time-dependent inhibitor for CYP3A4. Taken together, the results of the current study indicate that co-medication of CLZ with LEM may lead to increase in exposure to CLZ and risks of CLZ-related adverse events.

Habitual coffee consumption and risk of dementia in older persons: modulation by CYP1A2 polymorphism.

Higher coffee consumption has been associated with reduced dementia risk, yet with inconsistencies across studies. CYP1A2 polymorphisms, which affects caffeine metabolism, may modulate the association between coffee and the risk of dementia and Alzheimer's disease (AD). We included 5964 participants of the Three-City Study (mean age 74 years-old), free of dementia at baseline when they reported their daily coffee consumption, with available genome-wide genotyping and followed for dementia over a median of 9.0 (range 0.8-18.7) years. In Cox proportional-hazards models, the relationship between coffee consumption and dementia risk was modified by CYP1A2 polymorphism at rs762551 (p for interaction = 0.034). In multivariable-adjusted models, coffee intake was linearly associated with a decreased risk of dementia among carriers of the C allele only ("slower caffeine metabolizers"; HR for 1-cup increased [95% CI] 0.90 [0.83-0.97]), while in non-carriers ("faster caffeine metabolizers"), there was no significant association but a J-shaped trend toward a decrease in dementia risk up to 3 cups/day and increased risk beyond. Thus, compared to null intake, drinking ≥ 4 cups of coffee daily was associated with a reduced dementia risk in slower but not faster metabolizers (HR [95% CI] for ≥ 4 vs. 0 cup/day = 0.45 [0.25-0.80] and 1.32 [0.89-1.96], respectively). Results were similar when studying AD and another CYP1A2 candidate polymorphism (rs2472304), but no interaction was found with CYP1A2 rs2472297 or rs2470893. In this cohort, a linear association of coffee intake to lower dementia risk was apparent only among carriers of CYP1A2 polymorphisms predisposing to slower caffeine metabolism.

Influence of the CYP1A2 c.-163 A > C polymorphism in the effect of caffeine on fat oxidation during exercise: a pilot randomized, double-blind, crossover, placebo-controlled trial.

PURPOSE: The aim of this study was to determine the influence of the CYP1A2 c.-163 A > C (rs762551) polymorphism on the effect of oral caffeine intake on fat oxidation during exercise. METHODS: Using a pilot randomized, double-blind, crossover, placebo-controlled trial, 32 young and healthy individuals (women = 14, men = 18) performed an incremental test on a cycle ergometer with 3-min stages at workloads from 30 to 70% of maximal oxygen uptake (VO2max). Participants performed this test after the ingestion of (a) placebo; (b) 3 mg/kg of caffeine; (c) 6 mg/kg of caffeine. Fat oxidation rate during exercise was measured by indirect calorimetry. The influence of the CYP1A2 c.-163 A > C polymorphism in the effect of caffeine on fat oxidation rates during exercise was established with a three-way ANOVA (substance × genotype × intensity). RESULTS: Eight participants were genotyped as AA, 18 participants were CA heterozygotes, and 6 participants were CC. There was a main effect of substance (F = 3.348, p = 0.050) on fat oxidation rates during exercise with no genotype effect (F = 0.158, p = 0.959). The post hoc analysis revealed that, in comparison to the placebo, 3 and 6 mg/kg of caffeine increased fat oxidation at 40-50% VO2max in AA (all p < 0.050) and 50-60% VO2max in CA and CC participants (all p < 0.050). CONCLUSION: Oral intake of 3 and 6 mg/kg of caffeine increased fat oxidation rate during aerobic exercise in individuals with AA, CA and CC genotypes. This suggests that the effect of caffeine to enhance fat oxidation during exercise is not influenced by the CYP1A2 c.-163 A > C polymorphism. TRIAL REGISTRATION: The study was registered on clinicaltrials.gov with ID: NCT05975489.

Ancestral Sequence Reconstruction of a Cytochrome P450 Family Involved in Chemical Defense Reveals the Functional Evolution of a Promiscuous, Xenobiotic-Metabolizing Enzyme in Vertebrates.

The cytochrome P450 family 1 enzymes (CYP1s) are a diverse family of hemoprotein monooxygenases, which metabolize many xenobiotics including numerous environmental carcinogens. However, their historical function and evolution remain largely unstudied. Here we investigate CYP1 evolution via the reconstruction and characterization of the vertebrate CYP1 ancestors. Younger ancestors and extant forms generally demonstrated higher activity toward typical CYP1 xenobiotic and steroid substrates than older ancestors, suggesting significant diversification away from the original CYP1 function. Caffeine metabolism appears to be a recently evolved trait of the CYP1A subfamily, observed in the mammalian CYP1A lineage, and may parallel the recent evolution of caffeine synthesis in multiple separate plant species. Likewise, the aryl hydrocarbon receptor agonist, 6-formylindolo[3,2-b]carbazole (FICZ) was metabolized to a greater extent by certain younger ancestors and extant forms, suggesting that activity toward FICZ increased in specific CYP1 evolutionary branches, a process that may have occurred in parallel to the exploitation of land where UV-exposure was higher than in aquatic environments. As observed with previous reconstructions of P450 enzymes, thermostability correlated with evolutionary age; the oldest ancestor was up to 35 °C more thermostable than the extant forms, with a 10T50 (temperature at which 50% of the hemoprotein remains intact after 10 min) of 71 °C. This robustness may have facilitated evolutionary diversification of the CYP1s by buffering the destabilizing effects of mutations that conferred novel functions, a phenomenon which may also be useful in exploiting the catalytic versatility of these ancestral enzymes for commercial application as biocatalysts.

16R-HETE and 16S-HETE alter human cytochrome P450 1B1 enzyme activity probably through an allosteric mechanism.

Cytochrome P450 1B1 (CYP1B1) has been widely associated with the development of cardiac pathologies due to its ability to produce cardiotoxic metabolites like midchain hydroxyeicosatetraenoic acids (HETEs) from arachidonic acid (AA) through an allylic oxidation reaction. 16-HETE is a subterminal HETE that is also produced by CYP-mediated AA metabolism. 19-HETE is another subterminal HETE that was found to inhibit CYP1B1 activity, lower midchain HETEs, and have cardioprotective effects. However, the effect of 16-HETE enantiomers on CYP1B1 has not yet been investigated. We hypothesized that 16(R/S)-HETE could alter the activity of CYP1B1 and other CYP enzymes. Therefore, this study was carried out to investigate the modulatory effect of 16-HETE enantiomers on CYP1B1 enzyme activity, and to examine the mechanisms by which they exert these modulatory effects. To investigate whether these effects are specific to CYP1B1, we also investigated 16-HETE modulatory effects on CYP1A2. Our results showed that 16-HETE enantiomers significantly increased CYP1B1 activity in RL-14 cells, recombinant human CYP1B1, and human liver microsomes, as seen by the significant increase in 7-ethoxyresorufin deethylation rate. On the contrary, 16-HETE enantiomers significantly inhibited CYP1A2 catalytic activity mediated by the recombinant human CYP1A2 and human liver microsomes. 16R-HETE showed stronger effects than 16S-HETE. The sigmoidal binding mode of the enzyme kinetics data demonstrated that CYP1B1 activation and CYP1A2 inhibition occurred through allosteric regulation. In conclusion, our study provides the first evidence that 16R-HETE and 16S-HETE increase CYP1B1 catalytic activity through an allosteric mechanism.

Correlation between assessment of cytochrome P450 1A2 activity and enzyme activity scores, and their relation to clozapine exposure.

AIMS: Cytochrome P450 1A2 (CYP1A2) is involved in the metabolism of antipsychotic drugs such as clozapine and olanzapine. Personalization of these treatments requires an accurate estimation of CYP1A2 activity. In this study, we aimed (1) to evaluate the correlation between activity score (AS), covariate-corrected activity score (CCS) and the phenotype of CYP1A2 using a caffeine test probe and (2) to investigate their relationship with dose-adjusted clozapine concentrations in a subgroup of the cohort. METHODS: A multicentric, retrospective and observational study was carried out in the French university hospitals of Marseille and Tours. CYP1A2 activity was calculated by the paraxanthine/caffeine (17X/137X) ratio determined 4 h after an oral intake of 100 mg caffeine. AS was calculated according to the CYP1A2*1F alleles. CCS was calculated according to the CYP1A2*1F alleles, smoking status and the presence of concomitant inhibitors. RESULTS: As expected, among the 89 patients included, the 17X/137X ratio was significantly higher in patients who smoked. We found a significant but modest correlation between the 17X/137X ratio and CCS (R2 = 0.3, P = 1.74 × 10-8 ) but none between the 17X/137X ratio and AS (R2 = -0.007, P = 0.52). AS was not correlated with dose-adjusted clozapine levels, contrary to CCS (R2 = 0.19, P = 0.016) and especially the 17X/137X ratio (R2 = 0.42, P = 1.7 × 10-5 ). CONCLUSIONS: Correlation with clozapine concentrations showed the advantage of the 17X/137X ratio over the CCS in clozapine dose optimization. CYP1A2 activity, especially when determined by the caffeine probe, may be used to personalize clozapine dosing for patients experiencing treatment failure.

Evaluation of the effect of ritlecitinib on the pharmacokinetics of caffeine in healthy participants.

AIMS: This clinical study was conducted to evaluate the impact of ritlecitinib on the pharmacokinetics of caffeine, a cytochrome P450 1A2 (CYP1A2) substrate. METHODS: In this single-centre, single-arm, open-label, fixed-sequence study, healthy participants received a single 100-mg dose of caffeine on 2 separate occasions: on Day 1 of Period 1 as monotherapy and on Day 8 of Period 2 after oral administration of ritlecitinib 200 mg once daily for 8 days. Serial blood samples were collected and analysed using a validated liquid chromatography-mass spectrometry assay. Pharmacokinetic parameters were estimated by using a noncompartmental method. Safety was monitored by physical examination, vital signs, electrocardiograms and laboratory assessments. RESULTS: Twelve participants were enrolled and completed the study. Coadministration of caffeine 100 mg in the presence of steady-state levels of ritlecitinib (200 mg once daily) increased caffeine exposure compared with caffeine given alone. Area under the curve to infinity and maximum concentration of caffeine increased by approximately 165 and 10%, respectively, when coadministered with ritlecitinib. The ratios of the adjusted geometric means (90% confidence interval) for caffeine area under the curve to infinity and maximum concentration were 265.14% (234.12-300.26%) and 109.74% (103.90-15.91%), respectively, when caffeine was coadministered with steady-state ritlecitinib (test) compared with its administration alone (reference). Multiple doses of ritlecitinib when coadministered with a single dose of caffeine were generally safe and well tolerated in healthy participants. CONCLUSION: Ritlecitinib is a moderate inhibitor of CYP1A2 and can increase systemic exposures of CYP1A2 substrates.

Effect of capmatinib on the pharmacokinetics of substrates of CYP3A (midazolam) and CYP1A2 (caffeine) in patients with MET-dysregulated solid tumours.

BACKGROUND: Preclinical studies showed that capmatinib reversibly inhibits cytochrome P450 (CYP) 3A4 and CYP1A2 in a time-dependent manner. In this study, we evaluated the effect of capmatinib on the exposure of sensitive substrates of CYP3A (midazolam) and CYP1A2 (caffeine) in patients with mesenchymal-epithelial transition (MET)-dysregulated solid tumours. Besides pharmacokinetics, we assessed treatment response and safety. METHODS: This open-label, multicentre, single-sequence study consisted of a molecular prescreening period, a screening/baseline period of ≤28 days and a drug-drug interaction (DDI) phase of 12 days. On day 1 of the DDI phase, 37 patients received a single oral dose of midazolam 2.5 mg and caffeine 100 mg as a two-drug cocktail. Capmatinib 400 mg bid was administered from day 4 on a continuous dosing schedule. On day 9 of the DDI phase, patients were re-exposed to midazolam and caffeine. After the DDI phase, patients received capmatinib on continuous 21-day cycles until disease progression at the discretion of the investigator. RESULTS: A 22% (90% confidence interval [CI] 7-38%) increase in the midazolam maximum plasma concentration (Cmax ) was noted when administered with capmatinib, but this was deemed not clinically meaningful. Co-administration with capmatinib resulted in 134% (90% CI 108-163%) and 122% (90% CI 95-153%) increases in the caffeine area under the plasma concentration-time curve from time zero to infinity (AUCinf ) and area under the plasma concentration-time curve from time zero to the last measurable point (AUClast ), respectively, with no change in Cmax . Adverse events were consistent with the known capmatinib safety profile. No new safety signals were reported in this study. CONCLUSION: The data from this study demonstrated that capmatinib is a moderate CYP1A2 inhibitor. Capmatinib administration did not cause any clinically relevant changes in midazolam exposure.

Calculation of Human Melatonin Partial Metabolic Clearance in Healthy Adult Volunteers for Investigation of a Novel in Vivo CYP1A2 Phenotyping Method: A Pilot Study.

The method of administering caffeine as a probe to evaluate the phenotypic activity of the CYP1A2, has not yet been applied clinically. In contrast, if endogenous melatonin (MEL) metabolism can be used to assess CYP1A2 activity, it could be a simple method that does not require substance administration. The study aim was to calculate the MEL partial metabolic clearance (CLm(MEL)) from plasma MEL and its urinary metabolites and to test the potential of this approach as a novel CYP1A2 phenotyping method. Nine subjects were included in the study; 3 had 6 blood and 4 urine samples collected between 10:00 and 18:00 (collectively, the intraday sample). Nine subjects had 3 blood samples and 2-h urine samples collected between 10:00 and 12:00 once a week for 3 weeks (interday sample). The CLm(MEL) was calculated from the plasma area under the curve (AUC) of MEL (AUCMEL) and urinary MEL metabolites excretion (X6MEL). Among the intraday samples, the AUCMEL ranged from 6.45-13.17 pmol·h/L and X6MEL ranged from 0.204-0.899 nmol/2 h, showing a decrease in concentration over time. In contrast, the CLm(MEL) ranged from 30.52-69.57 L/h (within-individual percent relative standard deviation: 9.2-20.1%), showing no time-dependent variation. Large interindividual variability was observed in AUCMEL and X6MEL in the interday sample, but CLm(MEL) showed small interindividual variabilities. The CLm(MEL) was 1.8-fold higher for smokers than for nonsmokers. The results obtained in this study may be valuable in future studies of evaluating novel CYP1A2 phenotyping method.

Selective inhibitory effects of suberosin on CYP1A2 in human liver microsomes.

Suberosin is a natural phytoconstituent isolated from Citropsis articulata, especially employed for its anticoagulant properties. Although metabolic studies assessing suberosin have been conducted, it is possible interactions with drugs and food have not yet been investigated. In the present study, we analyzed the selective inhibitory effects of suberosin on cytochrome P450 (CYP) enzymes using a cocktail probe assay. Various concentrations of suberosin (0-50 µM) were incubated with isoform-specific CYP probes in human liver microsomes (HLMs). We found that suberosin significantly inhibited CYP1A2-catalyzed phenacetin O-deethylation, exhibiting IC50 values of 9.39 ± 2.05 and 3.07 ± 0.45 µM with and without preincubation in the presence of ß-NADPH, respectively. Moreover, suberosin showed concentration-dependent, but not time-dependent, CYP1A2 inhibition in HLMs, indicating that suberosin acts as a substrate and reversible CYP1A2 inhibitor. Using a Lineweaver-Burk plot, we found that suberosin competitively inhibited CYP1A2-catalyzed phenacetin O-deethylation. Furthermore, suberosin showed similar inhibitory effects on recombinant human CYP1A1 and 1A2. In conclusion, suberosin may elicit herb-drug interactions by selectively inhibiting CYP1A2 during the concurrent administration of drugs that act as CYP1A2 substrates.

Transcriptomics and metabolomics reveal the role of CYP1A2 in psoralen/isopsoralen-induced metabolic activation and hepatotoxicity.

Psoralen and isopsoralen are the pharmacologically important but hepatotoxic components in Psoraleae Fructus. The purpose of this study was to reveal the underlying mechanism of psoralen/isopsoralen-induced hepatotoxicity. Initially, we applied integrated analyses of transcriptomic and metabolomic profiles in mice treated with psoralen and isopsoralen, highlighting the xenobiotic metabolism by cytochromes P450 as a potential pathway. Then, with verifications of expression levels by qRT-PCR and western blot, affinities by molecular docking, and metabolic contributions by recombinant human CYP450 and mouse liver microsomes, CYP1A2 was screened out as the key metabolic enzyme. Afterwards, CYP1A2 induction and inhibition models in HepG2 cells and mice were established to verify the role of CYP1A2, demonstrating that induction of CYP1A2 aggravated the hepatotoxicity, and conversely inhibition alleviated the hepatotoxic effects. Additionally, we detected glutathione adducts with reactive intermediates of psoralen and isopsoralen generated by CYP1A2 metabolism in biosystems of recombinant human CYP1A2 and mouse liver microsomes, CYP1A2-overexpressed HepG2 cells, mice livers and the chemical reaction system using UPLC-Q-TOF-MS/MS. Ultimately, the high-content screening presented the cellular oxidative stress and relevant hepatotoxicity due to glutathione depletion by reactive intermediates. In brief, our findings illustrated that CYP1A2-mediated metabolic activation is responsible for the psoralen/isopsoralen-induced hepatotoxicity.

The Impact of the CYP2D6 and CYP1A2 Gene Polymorphisms on Response to Duloxetine in Patients with Major Depression.

Depression is a global mental health concern, and personalized treatment approaches are needed to optimize its management. This study aimed to investigate the influence of the CYP2D6 and CYP1A2 gene polymorphisms on the efficacy of duloxetine in reducing depressive and anxiety symptoms. A sample of 100 outpatients with major depression, who initiated monotherapy with duloxetine, were followed up. Polymorphisms in the CYP2D6 and CYP1A2 genes were assessed. The severity of depressive and anxiety symptoms was recorded using standardized scales. Adverse drug reactions (ADRs) were analyzed. Statistical analyses, including linear regression, were conducted to examine the relationships between genetic polymorphisms, clinical variables, and treatment outcomes. Patients with higher values of the duloxetine metabolic index (DMI) for CYP2D6, indicating a faster metabolism, achieved a greater reduction in anxiety symptoms. The occurrence of ADRs was associated with a lower reduction in anxiety symptoms. However, no significant associations were found between studied gene polymorphisms and reduction in depressive symptoms. No significant effects of the DMI for CYP1A2 were found. Patients with a slower metabolism may experience less benefit from duloxetine therapy in terms of anxiety symptom reduction. Personalizing treatment based on the CYP2D6 and CYP1A2 gene polymorphisms can enhance the effectiveness of antidepressant therapy and improve patient outcomes.

Hydration and Structural Adaptations of the Human CYP1A1, CYP1A2, and CYP1B1 Active Sites by Molecular Dynamics Simulations.

Cytochromes CYP1A1, CYP1A2, and CYP1B1, the members of the cytochrome P450 family 1, catalyze the metabolism of endogenous compounds, drugs, and non-drug xenobiotics which include substances involved in the process of carcinogenesis, cancer chemoprevention, and therapy. In the present study, the interactions of three selected polymethoxy-trans-stilbenes, analogs of a bioactive polyphenol trans-resveratrol (3,5,4'-trihydroxy-trans-stilbene) with the binding sites of CYP1 isozymes were investigated with molecular dynamics (MD) simulations. The most pronounced structural changes in the CYP1 binding sites were observed in two substrate recognition sites (SRS): SRS2 (helix F) and SRS3 (helix G). MD simulations show that the number and position of water molecules occurring in CYP1 APO and in the structures complexed with ligands are diverse. The presence of water in binding sites results in the formation of water-protein, water-ligand, and bridging ligand-water-protein hydrogen bonds. Analysis of the solvent and substrate channels opening during the MD simulation showed significant differences between cytochromes in relation to the solvent channel and the substrate channels 2c, 2ac, and 2f. The results of this investigation lead to a deeper understanding of the molecular processes that occur in the CYP1 binding sites and may be useful for further molecular studies of CYP1 functions.

Exploring the Mechanism of Hepatotoxicity Induced by Dictamnus dasycarpus Based on Network Pharmacology, Molecular Docking and Experimental Pharmacology.

The root bark of Dictamnus dasycarpus Turcz is a traditional Chinese medicine, Dictamni Cortex (DC), which is mainly used in the clinical treatment of skin inflammation, eczema, rubella, rheumatism, and gynecological inflammation. Unexpectedly, there are some cases of liver injury after the administration of DC. However, the mechanism of hepatotoxicity remains ambiguous. The aim of this study was to explore the mechanism and substance bases of DC hepatotoxicity based on network pharmacology and molecular docking, verified through pharmacological experiments. Partial prototype components and metabolites in vivo of quinoline alkaloids from DC were selected as candidate compounds, whose targets were collected from databases. Network pharmacology was applied to study the potential hepatotoxic mechanism after correlating the targets of candidate compounds with the targets of hepatotoxicity. Molecular docking was simulated to uncover the molecular mechanism. Furthermore, the hepatotoxicity of the extract and its constituents from DC was evaluated in vivo and in vitro. We constructed the "potential toxic components-toxic target-toxic pathway" network. Our results showed that the targets of DC included CYP1A2 and GSR, participating in heterologous steroid metabolism, REDOX metabolism, drug metabolism, heterocyclic metabolic processes, the synthesis of steroid hormone, cytochrome P450 metabolism, chemical carcinogens and bile secretion pathways. In vitro and in vivo experiments displayed that DC could result in a decrease in GSH-Px and oxidative stress, simultaneously inhibiting the expression of CYP1A2 and inducing hepatotoxicity. These results further indicated the mechanism of hepatotoxicity induced by Dictamnus dasycarpus, providing a basic theory to explore and prevent hepatotoxicity in the clinical usage of Dictamnus dasycarpus.

The synergistic effect of sea cucumber saponins and caffeine on preventing obesity in high-fat diet-fed mice by extending the action duration of caffeine.

BACKGROUND: Sea cucumber saponins (SCSs) exhibit a unique structure and high bioactivities and might have specialized implications on caffeine metabolic process by altering the activity of N-demethylation enzyme CYP1A2. The present study aimed to clarify the effects of SCS on caffeine metabolism in vivo and in vitro, as well as the synergistic anti-obesity effect of SCS and caffeine on high-fat diet-induced obese mice. RESULTS: Results found that SCS administration significantly postponed the elimination rate of caffeine and its metabolites in vivo, and further study found CYP1A2-mediated caffeine metabolism was remarkably inhibited in a dose-dependent manner in vitro. The synergistic effect of the SCS and caffeine combination could decrease the total weight of white adipose tissue by 52% compared with high-fat diet-treated group. CONCLUSION: SCS could prolong caffeine action time, and the combination of the two substances exhibited joint action on high-fat diet-induced obese mice. These findings might provide a basis for the development of functional foods and potential application using the combination of SCS and caffeine. © 2022 Society of Chemical Industry.