Polycyclic aromatic hydrocarbons (PAHs), including the Group 1 human carcinogen benzo[a]pyrene (BaP), are produced by the incomplete combustion of organic matter and thus are present in tobacco smoke, charbroiled food and diesel exhaust. The nematode Caenorhabditis elegans is an established model organism, however it lacks the genetic components of the classical mammalian cytochrome P450 (CYP)-mediated BaP-diol-epoxide metabolism pathway. We therefore introduced human CYP1A1 or CYP1A2 together with human epoxide hydrolase (EPHX) into the worm genome by Mos1-mediated Single Copy Insertion (MosSCI) and evaluated their response to BaP exposure via toxicological endpoints. Compared to wild-type control, CYP-humanised worms were characterised by an increase in pharyngeal pumping rate and a decrease in volumetric surface area. Furthermore, BaP exposure reduced reproductive performance, as reflected in smaller brood size, which coincided with the downregulation of the nematode-specific major sperm protein as determined by transcriptomics (RNAseq). BaP-mediated reproductive toxicity was exacerbated in CYP-humanised worms at higher exposure levels. Collagen-related genes were downregulated in BaP-exposed animals, which correlate with the reduction in volumetric size. Whole genome DNA sequencing revealed a higher frequency of T > G (A > C) base substitution mutations in worms expressing human CYP1A1;EPHX which aligned with an increase in DNA adducts identified via an ELISA method (but not classical 32P-postlabelling). Overall, the CYP-humanised worms provided new insights into the value of genome-optimised invertebrate models by identifying the benefits and limitations within the context of the (3Rs) concept which aims to replace, reduce and refine the use of animals in research.

• Klíčová slova
• Benzo[a]pyrene, CYP1A1, CYP1A2, Caenorhabditis elegans, DNA adducts, Mutational patterns, RNAseq,
• MeSH
• benzopyren * toxicita   MeSH
• Caenorhabditis elegans * genetika   účinky léků   MeSH
• cytochrom P-450 CYP1A1 * genetika   metabolismus   MeSH
• cytochrom P-450 CYP1A2 * genetika   metabolismus   MeSH
• geneticky modifikovaná zvířata MeSH
• karcinogeneze MeSH
• lidé MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• benzopyren * MeSH
• CYP1A1 protein, human MeSH Prohlížeč
• cytochrom P-450 CYP1A1 * MeSH
• cytochrom P-450 CYP1A2 * MeSH

BACKGROUND: Caffeine (CAF) ingestion improves performance in a broad range of exercise tasks. Nevertheless, the CAF-induced, dose-dependent effect on discipline-specific performance and cognitive functions in CrossFit/High-Intensity Functional Training (HIFT) has not been sufficiently investigated. The aim of this study was to evaluate the effect of acute supplementation of three different doses of CAF and placebo (PLA) on specific performance, reaction time (RTime), postural stability (PStab), heart rate (HR) and perceived exertion (RPE). METHODS: In a randomized double-blind placebo-controlled crossover design, acute pre-exercise supplementation with CAF (3, 6, or 9 mg/kg body mass (BM)) and PLA in 26 moderately trained CrossFit practitioners was examined. The study protocol involved five separate testing sessions using the Fight Gone Bad test (FGB) as the exercise performance evaluation and biochemical analyses, HR and RPE monitoring, as well as the assessment of RTime and PStab, with regard to CYP1A2 (rs762551) and ADORA2A (rs5751876) single nucleotide polymorphism (SNP). RESULTS: Supplementation of 6 mgCAF/kgBM induced clinically noticeable improvements in FGBTotal results, RTime and pre-exercise motor time. Nevertheless, there were no significant differences between any CAF doses and PLA in FGBTotal, HRmax, HRmean, RPE, pre/post-exercise RTime, PStab variables or pyruvate concentrations. Lactate concentration was higher (p < 0.05) before and after exercise in all CAF doses than in PLA. There was no effect of CYP1A2 or ADORA2A SNPs on performance. CONCLUSIONS: The dose-dependent effect of CAF supplementation appears to be limited to statistically nonsignificant but clinically considered changes on specific performance, RTime, PStab, RPE or HR. However, regarding practical CAF-induced performance implications in CrossFit/HIFT, 6 mgCAF/kgBM may be supposed as the most rational supplementation strategy.

• Klíčová slova
• cognitive function, ergogenic support, high-intensity functional exercise, sports dietetics, stability, supplementation,
• MeSH
• cytochrom P-450 CYP1A2 MeSH
• dvojitá slepá metoda MeSH
• klinické křížové studie MeSH
• kofein * farmakologie   MeSH
• kyselina mléčná MeSH
• lidé MeSH
• polyestery MeSH
• potravní doplňky MeSH
• reakční čas MeSH
• sportovní výkon * fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• randomizované kontrolované studie MeSH
• Názvy látek
• cytochrom P-450 CYP1A2 MeSH
• kofein * MeSH
• kyselina mléčná MeSH
• polyestery MeSH

The aryl hydrocarbon receptor (AhR) is a cytosolic ligand-activated transcription factor integral to various physiological and pathological processes. Among its diverse ligands, indole-based compounds have garnered attention due to their significant biological activity and potential therapeutic applications. This study explores the activation of AhR by structurally diverse halogenated indoles. We evaluated the transcriptional activity of AhR and cell viability in the human LS174T-AhR-luc reporter cell line. Among the tested compounds, 4-FI, 7-FI, 6-BrI, 7-BrI, 6-Cl-2-ox, 5-Br-2-ox, and 6-Br-2-ox activated AhR in a concentration-dependent manner, displaying high efficacy and potency. Molecular docking analysis revealed moderate binding affinities of these compounds to the PAS-B domain of AhR, corroborated by competitive radioligand binding assays. Functional assays showed that halogenated indoles induce the formation of AhR-ARNT heterodimer and enhance the binding of the AhR to the CYP1A1 promoter. Additionally, 4-FI and 7-FI exhibited anti-inflammatory properties in Caco-2 cell models, highlighting their potential for therapeutic applications. This study underscores the significance of the type and position of halogen moiety in indole scaffold, suggesting their potential as candidates for developing therapeutics drugs to treat conditions such as inflammatory bowel disease via AhR activation.

• Klíčová slova
• Aryl hydrocarbon receptor, Halogen, Indole derivatives, Inflammation,
• MeSH
• cytochrom P-450 CYP1A1 metabolismus   MeSH
• halogenace MeSH
• indoly * chemie   farmakologie   MeSH
• lidé MeSH
• molekulární struktura MeSH
• receptory aromatických uhlovodíků * metabolismus   chemie   MeSH
• simulace molekulového dockingu * MeSH
• transkripční faktory bHLH MeSH
• viabilita buněk účinky léků   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• AHR protein, human MeSH Prohlížeč
• cytochrom P-450 CYP1A1 MeSH
• indoly * MeSH
• receptory aromatických uhlovodíků * MeSH
• transkripční faktory bHLH MeSH

The endoplasmic reticulum 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 to 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 in the disordered microdomain. These findings identify three residues in the CYP1AN terminus as a novel microdomain-targeting motif of the P450s and provide a mechanistic explanation for the differential microdomain localization of CYP1A.

• Klíčová slova
• CYP1A1, CYP1A2, cytochrome P450, membrane charge depth, membrane protein, microdomain localization, microdomain-targeting motif, protein chimera, protein-lipid interaction, structure-function,
• MeSH
• cytochrom P-450 CYP1A1 * genetika   metabolismus   chemie   MeSH
• cytochrom P-450 CYP1A2 * metabolismus   genetika   chemie   MeSH
• endoplazmatické retikulum metabolismus   MeSH
• HEK293 buňky MeSH
• králíci MeSH
• lidé MeSH
• membránové mikrodomény metabolismus   genetika   MeSH
• proteinové domény MeSH
• sekvence aminokyselin MeSH
• simulace molekulární dynamiky MeSH
• substituce aminokyselin MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• cytochrom P-450 CYP1A1 * MeSH
• cytochrom P-450 CYP1A2 * MeSH

Dietary exposure to aflatoxin B1 (AFB1) is harmful to the health and performance of domestic animals. The hepatic cytochrome P450s (CYPs), CYP1A1 and CYP2A6, are the primary enzymes responsible for the bioactivation of AFB1 to the highly toxic exo-AFB1-8,9-epoxide (AFBO) in chicks. However, the transcriptional regulation mechanism of these CYP genes in the liver of chicks in AFB1 metabolism remains unknown. Dual-luciferase reporter assay, bioinformatics and site-directed mutation results indicated that specificity protein 1 (SP1) and activator protein-1 (AP-1) motifs were located in the core region -1,063/-948, -606/-541 of the CYP1A1 promoter as well as -636/-595, -503/-462, -147/-1 of the CYP2A6 promoter. Furthermore, overexpression and decoy oligodeoxynucleotide technologies demonstrated that SP1 and AP-1 were pivotal transcriptional activators regulating the promoter activity of CYP1A1 and CYP2A6. Moreover, bioactivation of AFB1 to AFBO could be increased by upregulation of CYP1A1 and CYP2A6 expression, which was trans-activated owing to the upregulalion of AP-1, rather than SP1, stimulated by AFB1-induced reactive oxygen species. Additionally, nano-selenium could reduce ROS, downregulate AP-1 expression and then decrease the expression of CYP1A1 and CYP2A6, thus alleviating the toxicity of AFB1. In conclusion, AP-1 and SP1 played important roles in the transactivation of CYP1A1 and CYP2A6 expression and further bioactivated AFB1 to AFBO in chicken liver, which could provide novel targets for the remediation of aflatoxicosis in chicks.

• Klíčová slova
• AP-1, CYP1A1, CYP2A6, SP1, aflatoxin B1, transcriptional activation,
• MeSH
• aflatoxin B1 * metabolismus   MeSH
• aktivace transkripce MeSH
• cytochrom P-450 CYP1A1 * genetika   metabolismus   MeSH
• cytochrom P450 CYP2A6 * metabolismus   genetika   MeSH
• játra * metabolismus   MeSH
• kur domácí metabolismus   MeSH
• promotorové oblasti (genetika) MeSH
• transkripční faktor AP-1 * metabolismus   genetika   MeSH
• transkripční faktor Sp1 * metabolismus   genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aflatoxin B1 * MeSH
• cytochrom P-450 CYP1A1 * MeSH
• cytochrom P450 CYP2A6 * MeSH
• transkripční faktor AP-1 * MeSH
• transkripční faktor Sp1 * MeSH

Herbal extracts represent a wide spectrum of biologically active ingredients with potential medical applications. By screening minor constituents of jasmine essential oil towards aryl hydrocarbon receptor (AhR) activity using a gene reporter assay (GRA), we found the antagonist effects of jasmone (3-methyl-2-[(2Z)-pent-2-en-1-yl]cyclopent-2-en-1-one). It inhibited 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-, benzo[a]pyrene (BaP)-, and 6-formylindolo[3,2-b]carbazole (FICZ)-triggered AhR-dependent luciferase activity in a concentration-dependent manner. However, the inhibition differed markedly between TCDD, BaP, and FICZ, with the latter being significantly less inhibited. The dose-response analysis confirmed an allosteric type of AhR antagonism. Furthermore, jasmone efficiently inhibited AhR activation by AhR agonists and microbial catabolites of tryptophan (MICTs). TCDD- and FICZ-inducible CYP1A1 expression in primary human hepatocytes was inhibited by jasmone, whereas in the human HepG2 and LS180 cells, jasmone antagonized only TCDD-activated AhR. Jasmone only partially displaced radiolabeled TCDD from its binding to mouse Ahr, suggesting it is not a typical orthosteric ligand of AhR. TCDD-elicited AhR nuclear translocation was not affected by jasmone, whereas downstream signaling events, including the formation of the AhR:ARNT complex and enrichment of the CYP1A1 promoter, were inhibited by jasmone. In conclusion, we show that jasmone is a potent allosteric antagonist of AhR. Such discovery may help to find and/or clarify the use of jasmone in pharmaco- and phytotherapy for conditions where AhR plays a key role.

• Klíčová slova
• AhR, CYP1A1, ChIP, HepG2, LS180, jasmone,
• MeSH
• cytochrom P-450 CYP1A1 genetika   metabolismus   MeSH
• lidé MeSH
• ligandy MeSH
• myši MeSH
• polychlorované dibenzodioxiny * škodlivé účinky   MeSH
• receptory aromatických uhlovodíků * antagonisté a inhibitory   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cytochrom P-450 CYP1A1 MeSH
• jasmone MeSH Prohlížeč
• ligandy MeSH
• polychlorované dibenzodioxiny * MeSH
• receptory aromatických uhlovodíků * MeSH

The human aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that is a pivotal regulator of human physiology and pathophysiology. Allosteric inhibition of AhR was previously thought to be untenable. Here, we identify carvones as noncompetitive, insurmountable antagonists of AhR and characterize the structural and functional consequences of their binding. Carvones do not displace radiolabeled ligands from binding to AhR but instead bind allosterically within the bHLH/PAS-A region of AhR. Carvones do not influence the translocation of ligand-activated AhR into the nucleus but inhibit the heterodimerization of AhR with its canonical partner ARNT and subsequent binding of AhR to the promoter of CYP1A1. As a proof of concept, we demonstrate physiologically relevant Ahr-antagonism by carvones in vivo in female mice. These substances establish the molecular basis for selective targeting of AhR regardless of the type of ligand(s) present and provide opportunities for the treatment of disease processes modified by AhR.

• MeSH
• cytochrom P-450 CYP1A1 genetika   MeSH
• kůže * metabolismus   účinky záření   MeSH
• ligandy MeSH
• myši MeSH
• promotorové oblasti (genetika) MeSH
• receptory aromatických uhlovodíků - jaderný translokátor * genetika   metabolismus   MeSH
• receptory aromatických uhlovodíků * genetika   metabolismus   MeSH
• ultrafialové záření škodlivé účinky   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cytochrom P-450 CYP1A1 MeSH
• ligandy MeSH
• receptory aromatických uhlovodíků - jaderný translokátor * MeSH
• receptory aromatických uhlovodíků * MeSH

The RTgill-W1 (gill), RTG-2 (gonad), and RTL-W1 (liver) cell lines derived from a freshwater fish rainbow trout (Oncorhynchus mykiss), were used to assess the toxicity of polyethylene terephthalate (PET) and two forms of polyvinyl chloride (PVC). Two size fractions (25-μm and 90-μm particles) were tested for all materials. The highest tested concentration was 1 mg/ml, corresponding to from 70 000 ± 9000 to 620 000 ± 57 000 particles/ml for 25-μm particles and from 2300 ± 100 to 11 000 ± 1000 particles/ml for 90-μm particles (depending on the material). Toxicity differences between commercial PVC dry blend powder and secondary microplastics created from a processed PVC were newly described. After a 24-h exposure, the cells were analyzed for changes in viability, 7-ethoxyresorufin-O-deethylase (EROD) activity, and reactive oxygen species (ROS) generation. In addition to the microplastic suspensions, leachates and particles remaining after leaching resuspended in fresh exposure medium were tested. The particles were subjected to leaching for 1, 8, and 15 days. The PVC dry blend (25 μm and 90 μm) and processed PVC (25 μm) increased ROS generation, to which leached chemicals appeared to be the major contributor. PVC dry blend caused substantially higher ROS induction than processed PVC, showing that the former is not suitable for toxicity testing, as it can produce different results from those of secondary PVC. The 90-μm PVC dry blend increased ROS generation only after prolonged leaching. PET did not induce any changes in ROS generation, and none of the tested polymers had any effect on viability or EROD activity. The importance of choosing realistic extraction procedures for microplastic toxicity experiments was emphasized. Conducting long-term experiments is crucial to detect possible environmentally relevant effects. In conclusion, the tested materials showed no acute toxicity to the cell lines.

• Klíčová slova
• Microplastics, Oncorhynchus mykiss, PET, PVC, Reactive oxygen species, Toxicity,
• MeSH
• buněčné linie MeSH
• chemické látky znečišťující vodu * analýza   MeSH
• cytochrom P-450 CYP1A1 metabolismus   MeSH
• mikroplasty toxicita   MeSH
• Oncorhynchus mykiss * metabolismus   MeSH
• plastické hmoty toxicita   metabolismus   MeSH
• polyethylentereftaláty toxicita   metabolismus   MeSH
• polyvinylchlorid toxicita   metabolismus   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chemické látky znečišťující vodu * MeSH
• cytochrom P-450 CYP1A1 MeSH
• mikroplasty MeSH
• plastické hmoty MeSH
• polyethylentereftaláty MeSH
• polyvinylchlorid MeSH
• reaktivní formy kyslíku MeSH

Aryl hydrocarbon receptor (AHR) plays pivotal roles in intestinal physiology and pathophysiology. Intestinal AHR is activated by numerous dietary, endogenous, and microbial ligands. Whereas the effects of individual compounds on AHR are mostly known, the effects of real physiological mixtures occurring in the intestine have not been studied. Using reporter gene assays and RT-PCR, we evaluated the combinatorial effects (3520 combinations) of 11 microbial catabolites of tryptophan (MICTs) on AHR. We robustly (n = 30) determined the potencies and relative efficacies of single MICTs. Synergistic effects of MICT binary mixtures were observed between low- or medium-efficacy agonists, in particular for combinations of indole-3-propionate and indole-3-lactate. Combinations comprising highly efficacious agonists such as indole-3-pyruvate displayed rather antagonist effects, caused by saturation of the assay response. These synergistic effects were confirmed by RT-PCR as CYP1A1 mRNA expression. We also tested mimic multicomponent and binary mixtures of MICTs, prepared based on the metabolomic analyses of human feces and colonoscopy aspirates, respectively. In this case, AHR responsiveness did not correlate with type of diet or health status, and the indole concentrations in the mixtures were determinative of gross AHR activity. Future systematic research on the synergistic activation of AHR by microbial metabolites and other ligands is needed.

• Klíčová slova
• aryl hydrocarbon receptor, indole derivatives, microbiome, mimic mixtures, tryptophan metabolites,
• MeSH
• cytochrom P-450 CYP1A1 genetika   metabolismus   MeSH
• indoly metabolismus   farmakologie   MeSH
• lidé MeSH
• ligandy MeSH
• messenger RNA metabolismus   MeSH
• propionáty MeSH
• pyruváty MeSH
• receptory aromatických uhlovodíků * metabolismus   MeSH
• střeva MeSH
• tryptofan * metabolismus   farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cytochrom P-450 CYP1A1 MeSH
• indoly MeSH
• ligandy MeSH
• messenger RNA MeSH
• propionáty MeSH
• pyruváty MeSH
• receptory aromatických uhlovodíků * MeSH
• tryptofan * MeSH

Targeting the aryl hydrocarbon receptor (AhR) is an emerging therapeutic strategy for multiple diseases (e.g., inflammatory bowel disease). Thermosporothrix hazakensis microbial metabolite 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) is a putative AhR endogenous ligand. To improve the chemical stability, we synthesized a series of ITE chemical mimics. Using a series of in vitro assays, we identified 2-(1H-indole-3-carbonyl)-N-methyl thiazole-4-carboxamide (ITE-CONHCH3) as a highly potent (EC50 = 1.6 nM) AhR agonist with high affinity (Ki = 88 nM). ITE-CONHCH3 triggered AhR nuclear translocation and dimerization of AhR-ARNT, enhanced AhR binding in the CYP1A1 promoter, and induced AhR-regulated genes in an AhR-dependent manner. The metabolic stability of ITE-CONHCH3 in a cell culture was 10 times higher than that of ITE. Finally, we observed protective effects of ITE-CONHCH3 in mice with DSS-induced colitis. Overall, we demonstrate and validate a concept of microbial metabolite mimicry in the therapeutic targeting of AhR.

• MeSH
• cytochrom P-450 CYP1A1 MeSH
• indoly farmakologie   terapeutické užití   MeSH
• kolitida * chemicky indukované   farmakoterapie   MeSH
• myši MeSH
• receptory aromatických uhlovodíků * agonisté   genetika   metabolismus   MeSH
• thiazoly farmakologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cytochrom P-450 CYP1A1 MeSH
• indoly MeSH
• receptory aromatických uhlovodíků * MeSH
• thiazoly MeSH