Hormonal regulation of CYP1A expression

Gut dysbiosis of Rana zhenhaiensis tadpoles after lead (Pb) exposure based on integrated analysis of microbiota and gut transcriptome

Lead (Pb) is a ubiquitously detected heavy metal pollutant in aquatic ecosystems. Previous studies focused mainly on the response of gut microbiota to Pb stress, with less emphasis on gene expression in intestine, thereby limiting the information about impacts of Pb on intestinal homeostasis in amphibians. Here, microbial community and transcriptional response of intestines in Rana zhenhaiensis tadpoles to Pb exposure were evaluated. Our results showed that 10 μg/L Pb significantly decreased bacterial diversity compared to the controls by the Simpson index. Additionally, 1000 μg/L Pb exposure resulted in a significant reduction in the abundance of Fusobacteriota phylum and Cetobacterium genus but a significant expansion in Hafnia-Obesumbacterium genus. Moreover, transcriptome analysis revealed that about 90 % of the DEGs (8458 out of 9450 DEGs) were down-regulated in 1000 μg/L Pb group, mainly including genes annotated with biological functions in fatty acid degradation, and oxidative phosphorylation, while up-regulated DEGs involved in metabolism of xenobiotics by cytochrome P450. The expression of Gsto1, Gsta5, Gstt4, and Nadph showed strong correlation with the abundance of genera Serratia, Lactococcus, and Hafnia-Obesumbacterium. The findings of this study provide important insights into understanding the influence of Pb on intestinal homeostasis in amphibians.

Comparative Analysis of mRNA and lncRNA Expression Profiles in Testicular Tissue of Sexually Immature and Sexually Mature Mongolian Horses

Testicular development and spermatogenesis are tightly regulated by both coding and non-coding genes, with mRNA and lncRNA playing crucial roles in post-transcriptional gene expression regulation. However, there are significant differences in regulatory mechanisms before and after sexual maturity. Nevertheless, the mRNAs and lncRNAs in the testes of Mongolian horses have not been systematically identified. In this study, we first identified the testicular tissues of sexually immature and sexually mature Mongolian horses at the tissue and protein levels, and comprehensively analyzed the expression profiles of mRNA and lncRNA in the testes of 1-year-old (12 months, n = 3) and 10-year-old (n = 3) Mongolian horses using RNA sequencing technology. Through gene expression analysis, we identified 16,582 mRNAs and 2128 unknown lncRNAs that are commonly expressed in both sexually immature and sexually mature Mongolian horses. Meanwhile, 9217 mRNAs (p < 0.05) and 2191 unknown lncRNAs (p < 0.05) were identified as differentially expressed between the two stages, which were further validated by real-time fluorescent quantitative PCR and analyzed using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). The analysis results showed that genes in the sexually immature stage were mainly enriched in terms related to cellular infrastructure, while genes in the sexually mature stage were enriched in terms associated with hormones, metabolism, and spermatogenesis. In summary, the findings of this study provide valuable resources for a deeper understanding of the molecular mechanisms underlying testicular development and spermatogenesis in Mongolian horses and offer new perspectives for future related research.

On the Possible Effect of Phytic Acid (Myo-Inositol Hexaphosphoric Acid, IP6) on Cytochromes P450 and Systems of Xenobiotic Metabolism in Different Hepatic Models

As compounds of natural origin enter human body, it is necessary to investigate their possible interactions with the metabolism of drugs and xenobiotics in general, namely with the cytochrome P450 (CYP) system. Phytic acid (myo-inositol hexaphosphoric acid, IP6) is mainly present in plants but is also an endogenous compound present in mammalian cells and tissues. It has been shown to exhibit protective effect in many pathological conditions. For this paper, its interaction with CYPs was studied using human liver microsomes, primary human hepatocytes, the HepG2 cell line, and molecular docking. Docking experiments and absorption spectra demonstrated the weak ability of IP6 to interact in the heme active site of CYP1A. Molecular docking suggested that IP6 preferentially binds to the protein surface, whereas binding to the active site of CYP1A2 was found to be less probable. Subsequently, we investigated the ability of IP6 to modulate the metabolism of xenobiotics for both the mRNA expression and enzymatic activity of CYP1A enzymes. Our findings revealed that IP6 can slightly modulate the mRNA levels and enzyme activity of CYP1A. However, thanks to the relatively weak interactions of IP6 with CYPs, the chances of the mechanisms of clinically important drug-drug interactions involving IP6 are low.

Psoralen and isopsoralen from Psoraleae Fructus aroused hepatotoxicity via induction of aryl hydrocarbon receptor-mediated CYP1A2 expression

ETHNOPHARMACOLOGICAL RELEVANCE

Psoraleae Fructus (PF), a traditional Chinese medicine, has long been used to treat diseases such as cancer, osteoporosis and leukoderma. Psoralen and isopsoralen are main bioactive ingredients of PF with anti-tumor, anti-inflammatory, estrogen-like neuroprotection, etc., meanwhile they are also representative hepatotoxic components of PF. Hepatic CYP1A2 has been reported to be the important metabolic enzymes involved in psoralen and isopsoralen-induced hepatotoxicity. However, the relationship between the hepatotoxicity and CYP1A2 expression, and the underlying mechanism of regulating CYP1A2 expression remain unclear.

AIM OF STUDY

The aim of this study was to explore the associated mechanism between psoralen or isopsoralen induced hepatotoxicity and activated aryl hydrocarbon receptor (AhR)-mediated transcriptional induction of CYP1A2 in vitro and in vivo.

MATERIALS AND METHODS

Psoralen and isopsoralen at different doses were treated on HepG2 cells (10, 25, 50, 100, 200 μM for 2, 12, 24, 36, 48 h) and mice (20, 80, 160 mg/kg for 3, 7, 14 days) for different time, to assess the correlation of induced hepatotoxicity and CYP1A2 mRNA and protein expression in vivo and in vitro, as well as the effect on CYP1A2 enzyme activity evaluated by phenacetin metabolism. In addition, the potential mechanism of the regulation of CYP1A2 expression mediated by AhR was explored through nucleocytoplasmic shuttling, immunofluorescence, cellular thermal shift assay and molecular docking, etc. RESULTS: Psoralen and isopsoralen induced cytotoxicity in HepG2 cells, and hepatomegaly, biochemicals disorder and tissue pathological impairment in mice, respectively in dose- and time-dependent manners. Simultaneously accompanied with elevated levels of CYP1A2 mRNA and protein in the same trend, and the CYP1A2 activity was remarkably inhibited in vitro but significantly elevated overall in vivo. Besides, psoralen and isopsoralen bound to AhR and activated translocation of AhR from the cytoplasm to the nucleus, leading to the transcriptional induction of target gene CYP1A2.

CONCLUSIONS

Hepatotoxicities in HepG2 cells and mice aroused by psoralen and isopsoralen were related to the induction of CYP1A2 expression and activity, whose underlying mechanism might be psoralen or isopsoralen activated AhR translocation and induced increase of CYP1A2 transcriptional expression. Hopefully, these finding are conductive to propose an alert about the combined usage of psoralen or isopsoralen and AhR ligands or CYP1A2 substrates in clinical practice.

Aryl hydrocarbon receptor (AhR)-mediated signaling as a critical regulator of skeletal cell biology

The aryl hydrocarbon receptor (AhR) has been implicated in regulating skeletal progenitor cells and the activity of bone-forming osteoblasts and bone-resorbing osteoclasts, thereby impacting bone mass and the risk of skeletal fractures. The AhR also plays an important role in the immune system within the skeletal niche and in the differentiation of mesenchymal stem cells into other cell lineages including chondrocytes and adipocytes. This transcription factor responds to environmental pollutants which can act as AhR ligands, initiating or interfering with various signaling cascades to mediate downstream effects, and also responds to endogenous ligands including tryptophan metabolites. This review comprehensively describes the reported roles of the AhR in skeletal cell biology, focusing on mesenchymal stem cells, osteoblasts, and osteoclasts, and discusses how AhR exhibits sexually dimorphic effects in bone. The molecular mechanisms mediating AhR's downstream effects are highlighted to emphasize the potential importance of targeting this signaling cascade in skeletal disorders.

The impact of noradrenergic neurotoxin DSP-4 and noradrenaline transporter knockout (NET-KO) on the activity of liver cytochrome P450 3A (CYP3A) in male and female mice

Background

Our earlier studies have shown that the brain noradrenergic system regulates cytochrome P450 (CYP) in rat liver via neuroendocrine mechanism. In the present work, a comparative study on the effect of intraperitoneal administration of the noradrenergic neurotoxin DSP-4 and the knockout of noradrenaline transporter (NET-KO) on the CYP3A in the liver of male and female mice was performed.

Methods

The experiments were conducted on C57BL/6J WT and NET^–/– male/female mice. DSP-4 was injected intraperitoneally as a single dose (50 mg/kg ip.) to WT mice. The activity of CYP3A was measured as the rate of 6β-hydroxylation of testosterone in liver microsomes. The CYP3A protein level was estimated by Western blotting.

Results

DSP-4 evoked a selective decrease in the noradrenaline level in the brain of male and female mice. At the same time, DSP-4 reduced the CYP3A activity in males, but not in females. The level of CYP3A protein was not changed. The NET knockout did not affect the CYP3A activity/protein in both sexes.

Conclusions

The results with DSP-4 treated mice showed sex-dependent differences in the regulation of liver CYP3A by the brain noradrenergic system (with only males being responsive), and revealed that the NET knockout did not affect CYP3A in both sexes. Further studies into the hypothalamic–pituitary–gonadal hormones in DSP-4 treated mice may explain sex-specific differences in CYP3A regulation, whereas investigation of monoaminergic receptor sensitivity in the hypothalamic/pituitary areas of NET^–/– mice will allow for understanding a lack of changes in the CYP3A activity in the NET-KO animals.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43440-022-00406-8.

Toxicity screening of bisphenol A replacement compounds: cytotoxicity and mRNA expression in LMH 3D spheroids

Previously, we showed that the chicken LMH cell line cultured as 3D spheroids may be a suitable animal free alternative to primary chicken embryonic hepatocytes (CEH) for avian in vitro chemical screening. In this study, cytotoxicity and mRNA expression were determined in LMH 3D spheroids following exposure to bisphenol A (BPA), five BPA replacement compounds (BPF, TGSH, DD-70, BPAF, BPSIP), and 17β estradiol (E2). Results were compared to an earlier study that evaluated the same endpoints for these chemicals in CEH. BPA and the replacement compounds had LC50 values ranging from 16.6 to 81.8 μM; DD-70 and BPAF were the most cytotoxic replacements (LC50 = 17.23 ± 4.51 and 16.6 ± 4.78 μM). TGSH and DD-70 modulated the greatest number of genes, although fewer than observed in CEH. Based on the expression of apovitellenin and vitellogenin, BPAF was the most estrogenic compound followed by BPF, BPSIP, and BPA. More estrogen-responsive genes were modulated in LMH spheroids compared to CEH. Concentration-dependent gene expression revealed that DD-70 and BPAF altered genes related to lipid and bile acid regulation. Overall, cytotoxicity and clustering of replacements based on gene expression profiles were similar between LMH spheroids and CEH. In addition to generating novel gene expression data for five BPA replacement compounds in an in vitro avian model, this research demonstrates that LMH spheroids may represent a useful animal free alternative for avian toxicity testing.

Steroid Hormones Protect against Fluoranthene Ethoxyresorufin-O-Deethylase (EROD) Activity Inhibition

The physiological conditions of an organism may influence its ability to cope with environmental stressors, such as contaminants. Biotransformation and the endocrine system interact with each other to promote animal’s fitness. However, little is known regarding the interaction between hormones and response to pollutants such as polycyclic aromatic hydrocarbons (PAHs). In this in vitro study, we aimed to increase the knowledge regarding the effects of steroid hormones on ethoxyresorufin-O-deethylase (EROD) activity inhibited by contaminants. The effects on in vivo induced EROD activity of Anguilla anguilla were assessed by conducting single and combined exposures to fluoranthene (FL) and to physiological levels of two major steroid hormones (cortisol and 17ß-estradiol). Hepatic microsome exposure to the lowest concentrations of FL (0.1 and 0.3 µM), as well as to cortisol and 17ß-estradiol (E2), led to significant EROD activity induction. However, the highest tested concentrations of FL (0.9 and 2.7 µM) significantly inhibited this enzymatic activity. When microsomes were simultaneously exposed to 0.9 µM FL and one of the hormones, both cortisol and E2 were able to decrease the inhibitory effects, with the former completely reverting EROD activity inhibition. These findings support the idea that cortisol and E2 can help prevent the inhibitory effects of PAHs over biotransformation enzymes, highlighting the physiological relevance of these hormones.

CYP1A2 mRNA Expression Rather than Genetic Variants Indicate Hepatic CYP1A2 Activity

CYP1A2, one of the most abundant hepatic cytochrome P450 enzymes, is involved in metabolism of several drugs and carcinogenic compounds. Data on the significance of CYP1A2 genetic polymorphisms in enzyme activity are highly inconsistent; therefore, the impact of CYP1A2 genetic variants (−3860G>A, −2467delT, −739T>G, −163C>A, 2159G>A) on mRNA expression and phenacetin O-dealkylation selective for CYP1A2 was investigated in human liver tissues and in psychiatric patients belonging to Caucasian populations. CYP1A2*1F, considered to be associated with high CYP1A2 inducibility, is generally identified by the presence of −163C>A polymorphism; however, we demonstrated that −163C>A existed in several haplotypes (CYP1A2*1F, CYP1A2*1L, CYP1A2*1M, CYP1A2*1V, CYP1A2*1W), and consequently, CYP1A2*1F was a much rarer allelic variant (0.4%) than reported in Caucasian populations. Of note, −163C>A polymorphism was found to result in an increase of neither mRNA nor the activity of CYP1A2. Moreover, hepatic CYP1A2 activity was associated with hepatic or leukocyte mRNA expression rather than genetic polymorphisms of CYP1A2. Consideration of non-genetic phenoconverting factors (co-medication with CYP1A2-specific inhibitors/inducers, tobacco smoking and non-specific factors, including amoxicillin+clavulanic acid therapy or chronic alcohol consumption) did not much improve genotype−phenotype estimation. In conclusion, CYP1A2-genotyping is inappropriate for the prediction of CYP1A2 function; however, CYP1A2 mRNA expression in leukocytes can inform about patients’ CYP1A2-metabolizing capacity.

Biotransformation of 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ) can contribute to high levels of 2,4,6-tribromophenol (2,4,6-TBP) in humans

2,4,6-Tribromophenol (2,4,6-TBP) is a brominated flame retardant that accumulates in human tissues and is a potential toxicant. Previous studies found 2,4,6-TBP levels in human tissues were significantly higher than those of brominated flame retardants measured in the same samples. In contrast, the levels of 2,4,6-TBP in the environment and foodstuff are not elevated, suggesting a low potential for direct intake through environmental exposure or diet. Here, we hypothesized that high levels of 2,4,6-TBP in human tissues are partially from the indirect exposure sources, such as biotransformation of highly brominated substances. We conducted in vitro assays utilizing human and rat liver microsomes to compare the biotransformation rates of four highly brominated flame retardants, which could potentially transform to 2,4,6-TBP, including decabromodiphenyl ethane (DBDPE), 2,4,6-tris-(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), and tetrabromobisphenol A (TBBPA). Our results show that TTBP-TAZ rapidly metabolizes in both human and rat liver microsomes with a half-life of 1.1 and 2.2 h, respectively, suggesting that TTBP-TAZ is a potential precursor of 2,4,6-TBP. In contrast, 2,4,6-TBP was not formed as a result of biotransformation of TBBPA, BTBPE, and DBDPE in both human and rat liver microsomes. We applied suspect and target screening to explore the metabolic pathways of TTBP-TAZ and identified 2,4,6-TBP as a major metabolite of TTBP-TAZ accounting for 87% of all formed metabolites. These in vitro results were further tested by an in vivo experiment in which 2,4,6-TBP was detected in the rat blood and liver at concentrations of 270 ± 110 and 50 ± 14 μg/g lipid weight, respectively, after being exposed to 250 mg/kg body weight/day of TTBP-TAZ for a week. The hepatic mRNA expression demonstrated that TTBP-TAZ significantly activates the aryl hydrocarbon receptor (AhR) and promotes fatty degeneration (18 and 28-fold change compared to control, respectively) in rats.

The Selective NMDA Receptor GluN2B Subunit Antagonist CP-101,606 with Antidepressant Properties Modulates Cytochrome P450 Expression in the Liver

Recent research indicates that selective NMDA receptor GluN2B subunit antagonists may become useful for the treatment of major depressive disorders. We aimed to examine in parallel the effect of the selective NMDA receptor GluN2B subunit antagonist CP-101,606 on the pituitary/serum hormone levels and on the regulation of cytochrome P450 in rat liver. CP-101,606 (20 mg/kg ip. for 5 days) decreased the activity of CYP1A, CYP2A, CYP2B, CYP2C11 and CYP3A, but not that of CYP2C6. The alterations in enzymatic activity were accompanied by changes in the CYP protein and mRNA levels. In parallel, a decrease in the pituitary growth hormone-releasing hormone, and in serum growth hormone and corticosterone (but not T₃ and T₄) concentration was observed. After a 3-week administration period of CP-101,606 less changes were found. A decrease in the CYP3A enzyme activity and protein level was still maintained, though no change in the mRNA level was found. A slight decrease in the serum concentration of corticosterone was also maintained, while GH level returned to the control value. The obtained results imply engagement of the glutamatergic system in the neuroendocrine regulation of cytochrome P450 and potential involvement of drugs acting on NMDA receptors in metabolic drug–drug interactions.

Frogs Respond to Commercial Formulations of the Biopesticide Bacillus thuringiensis var. israelensis, Especially Their Intestine Microbiota

It is generally believed that Bacillus thuringiensis var. israelensis (Bti) biopesticides are harmless to non-target organisms; however, new research shows controversial results. We exposed acutely and chronicallyLithobates sylvaticusandAnaxyrus americanus tadpoles until metamorphic climax to VectoBac 200G (granules) and VectoBac 1200L (aqueous suspension) at 300-20,000 ITU/L covering field-relevant concentrations and higher. The data show that the exposure parameters tested did not affect significantly the survival, total length, total weight, hepatosomatic index, gonadosomatic index, the expression of genes of interest (i.e., related to xenobiotic exposure, oxidative stress, and metamorphosis), and the intestine tissue layer detachment ofL. sylvaticusandA. americanus in a concentration-response pattern. In contrast, VectoBac 200G significantly increased the median time to metamorphosis ofL. sylvaticus tadpoles by up to 3.5 days and decreased the median by up to 1 day inA. americanus. VectoBac 1200L significantly increased the median time to metamorphosis ofL. sylvaticusandA. americanustadpoles by up to 4.5 days. Also, the exposure to VectoBac 200G and 1200L altered the intestine bacterial community composition inA. americanus at application rates recommended by the manufacturer, which led to an increase in the relative abundance of Verrucomicrobia, Firmicutes, Bacteroidetes, and Actinobacteria. Changes in the intestine microbiota might impact the fitness of individuals, including the susceptibility to parasitic infections. Our results indicate that the effect of Bti commercial products is limited; however, we recommend that Bti-spraying activities in amphibian-rich ecosystems should be kept minimal until there is more conclusive research to assess if the changes in the time to metamorphosis and microbiota can lead to negative outcomes in amphibian populations and, eventually, the functioning of ecosystems.

Differential Impacts of Phenol Red on Benzo[a]pyrene and Dexamethasone-Modified Cytochrome P450s in Human Cancer Cells

&lt;b&gt;Background and Objective:&lt;/b&gt; Phenol red, the pH indicator in cell culture media, influences the expression of cytochrome P450s (CYPs) in cell lines. This study aimed to examine how phenol red modified CYP induction by benzo[&lt;i&gt;a&lt;/i&gt;]pyrene and dexamethasone in human hepatocarcinoma (HepG2), colorectal adenocarcinoma (Caco-2) and choriocarcinoma (BeWo) cells. &lt;b&gt;Materials and Methods:&lt;/b&gt; The cells (1×10&lt;sup&gt;5&lt;/sup&gt; cells/well in a 24-well plate) were incubated with benzo[&lt;i&gt;a&lt;/i&gt;]pyrene (0.1, 1 and 10 μM) or dexamethasone (1, 5 and 10 μM) in either phenol red or phenol red-free media for 24 hrs. The mRNA expression of CYPs was determined by Real-Time Polymerase Chain Reaction (RT/qPCR). &lt;b&gt;Results:&lt;/b&gt; Phenol red enhanced expression of benzo[&lt;i&gt;a&lt;/i&gt;]pyrene-induced CYP1A2 inHepG2 and BeWo cells and suppressed benzo[&lt;i&gt;a&lt;/i&gt;]pyrene-induced CYP2A6 expression in HepG2 and Caco-2 cells, benzo[&lt;i&gt;a&lt;/i&gt;]pyrene induced CYP2B6 expression in HepG2 cells and benzo[&lt;i&gt;a&lt;/i&gt;]pyrene- and dexamethasone-induced CYP3A4 expression in HepG2 and Caco-2 cells. The expression of CYP3A5 was affected differently in HepG2 and Caco-2 cell lines. Phenol red enhanced benzo[&lt;i&gt;a&lt;/i&gt;]pyrene- and dexamethasone-induced CYP3A5 expression in Caco-2 cells but suppressed benzo[&lt;i&gt;a&lt;/i&gt;]pyrene- and dexamethasone-induced CYP3A5 expression in HepG2 cells. &lt;b&gt;Conclusion:&lt;/b&gt; Phenol red differentially influenced expression of benzo[&lt;i&gt;a&lt;/i&gt;]pyrene- and dexamethasone-induced CYP1A2, CYP2A6, CYP2B6, CYP3A4 and CYP3A5 mRNAs in HepG2, Caco-2 and BeWo cells. Therefore, the inclusion of phenol red in cell culture media is of concern in studies of drug and xenobiotic metabolism via CYPs in human cell line models.

The Effect of Chronic Iloperidone Treatment on Cytochrome P450 Expression and Activity in the Rat Liver: Involvement of Neuroendocrine Mechanisms

In order to achieve a desired therapeutic effect in schizophrenia patients and to maintain their mental wellbeing, pharmacological therapy needs to be continued for a long time, usually from the onset of symptoms and for the rest of the patients' lives. The aim of our present research is to find out the in vivo effect of chronic treatment with atypical neuroleptic iloperidone on the expression and activity of cytochrome P450 (CYP) in rat liver. Male Wistar rats received a once-daily intraperitoneal injection of iloperidone (1 mg/kg) for a period of two weeks. Twenty-four hours after the last dose, livers were excised to study cytochrome P450 expression (mRNA and protein) and activity, pituitaries were isolated to determine growth hormone-releasing hormone (GHRH), and blood was collected for measuring serum concentrations of hormones and interleukin. The results showed a broad spectrum of changes in the expression and activity of liver CYP enzymes, which are important for drug metabolism (CYP1A, CYP2B, CYP2C, and CYP3A) and xenobiotic toxicity (CYP2E1). Iloperidone decreased the expression and activity of CYP1A2, CP2B1/2, CYP2C11, and CYP3A1/2 enzymes but increased that of CYP2E1. The CYP2C6 enzyme remained unchanged. At the same time, the level of GHRH, GH, and corticosterone decreased while that of T₃ increased, with no changes in IL-2 and IL-6. The presented results indicate neuroendocrine regulation of the investigated CYP enzymes during chronic iloperidone treatment and suggest a possibility of pharmacokinetic/metabolic interactions produced by the neuroleptic during prolonged combined treatment with drugs that are substrates of iloperidone-affected CYP enzymes.

Endocrine disrupting chemicals and metabolic disorders in the liver: What if we also looked at the female side?

Endocrine disrupting chemicals (EDCs) are linked to the worldwide epidemic incidence of metabolic disorders and fatty liver diseases, which affects quality of life and represents a high economic cost to society. Energy homeostasis exhibits strong sexual dimorphic traits, and metabolic organs respond to EDCs depending on sex, such as the liver, which orchestrates both drug elimination and glucose and lipid metabolism. In addition, fatty liver diseases show a strong sexual bias, which in part could also originate from sex differences observed in gut microbiota. The aim of this review is to highlight significant differences in endocrine and metabolic aspects of the liver, between males and females throughout development and into adulthood. It is also to illustrate how the male and female liver differently cope with exposure to various EDCs such as bisphenols, phthalates and persistent organic chemicals in order to draw attention to the need to include both sexes in experimental studies. Interesting data come from analyses of the composition and diversity of the gut microbiota in males exposed to the mentioned EDCs showing significant correlations with hepatic lipid accumulation and metabolic disorders but information on females is lacking or incomplete. As industrialization increases, the list of anthropogenic chemicals to which humans will be exposed will also likely increase. In addition to strengthening existing regulations, encouraging populations to protect themselves and promoting the substitution of harmful chemicals with safe products, innovative strategies based on sex differences in the gut microbiota and in the gut-liver axis could be optimistic outlook.

Potential functional variants in AHR signaling pathways are associated with age at puberty in swine

Puberty in female pigs is defined as age at first estrus and gilts that have an earlier age at puberty are more likely to have greater lifetime productivity. Because age at puberty is predictive for sow longevity and lifetime productivity, but not routinely measured in commercial herds, it would be beneficial to use genomic or marker-assisted selection to improve these traits. A GWAS at the US Meat Animal Research Center (USMARC) identified several loci associated with age at puberty in pigs. Candidate genes in these regions were scanned for potential functional variants using sequence information from the USMARC swine population founder animals and public databases. In total, 135 variants (SNP and insertion/deletions) in 39 genes were genotyped in 1284 phenotyped animals from a validation population sired by Landrace and Yorkshire industry semen using the Agena MassArray system. Twelve variants in eight genes were associated with age at puberty (P < 0.005) with estimated additive SNP effects ranging from 1.6 to 5.3 days. Nine of these variants were non-synonymous coding changes in AHR, CYP1A2, OR2M4, SDCCAG8, TBC1D1 and ZNF608, two variants were deletions of one and four codons in aryl hydrocarbon receptor, AHR, and the most significant SNP was near an acceptor splice site in the acetyl-CoA carboxylase alpha, ACACA. Several of the loci identified have a physiological and a genetic role in sexual maturation in humans and other animals and are involved in AHR-mediated pathways. Further functional validation of these variants could identify causative mutations that influence age at puberty in gilts and possibly sow lifetime productivity.

Non-apnea sleep disorder and its risk for all kinds of injuries: A 14-year follow-up for a nationwide population-based retrospective study

Non-apnea sleep disorder (NASD) increases the risk of motor vehicle accidents. However, systemic review of NASD and its risk for all causes of injury is lacking. The aim of the present study was to provide a detailed demographic data on NASD and all causes of injury in a 14-year follow up.Our study utilized outpatient and inpatient data from the Longitudinal Health Insurance Database between 2000 and 2013 in Taiwan. We enrolled 989,753 individuals aged ≥20 years who were diagnosed with NASD as outpatients ≥3 times or inpatients ≥1 time. We matched the study cohort with a comparison cohort by age, index date and comorbidities at a ratio of 1:4. We used Cox proportional hazards regression to analyze the association of NASD and the cause of injury.In this 14-year follow up study, patients with NASD had 12.96% increased risk of injury compared to that of the control cohort. Fall was the first place of the cause of injury with 670.26 per 105 PYs. In the stratified age group, patients aged ≧65 years had the highest risk of injury (adjusted HR= 1.381; P < .001). Kaplan-Meier analysis showed that the incidence of injury between the with- and without-NASD cohorts started from the first year and persisted until the end of the follow-up.Our study demonstrates that NASD patients were associated with higher risk of all causes of injuries, with falling being the most prevalent diagnosis. The general public should be more aware of this neglected issue of NASD.

The Activation of Procarcinogens by CYP1A1/1B1 and Related Chemo-Preventive Agents: A Review

CYP1A1 and CYP1B1 are extrahepatic P450 family members involved in the metabolism of procarcinogens, such as PAHs, heterocyclic amines and halogen-containing organic compounds. CYP1A1/1B1 also participate in the metabolism of endogenous 17-β-estradiol, producing estradiol hydroquinones, which are the intermediates of carcinogenic semiquinones and quinones. CYP1A1 and CYP1B1 proteins share approximately half amino acid sequence identity but differ in crystal structures. As a result, CYP1A1 and CYP1B1 have different substrate specificity to chemical procarcinogens. This review will introduce the general molecular biology knowledge of CYP1A1/1B1 and the metabolic processes of procarcinogens regulated by these two enzymes. Over the last four decades, a variety of natural products and synthetic compounds which interact with CYP1A1/1B1 have been identified as effective chemo-preventive agents against chemical carcinogenesis. These compounds are mainly classified as indirect or direct CYP1A1/1B1 inhibitors based on their distinct mechanisms. Indirect CYP1A1/1B1 inhibitors generally impede the transcription and translation of CYP1A1/1B1 genes or interfere with the translocation of aryl hydrocarbon receptor (AHR) from the cytosolic domain to the nucleus. On the other hand, direct inhibitors inhibit the catalytic activities of CYP1A1/1B1. Based on the structural features, the indirect inhibitors can be categorized into the following groups: flavonoids, alkaloids and synthetic aromatics, whereas the direct inhibitors can be categorized into flavonoids, coumarins, stilbenes, sulfur containing isothiocyanates and synthetic aromatics. This review will summarize the in vitro and in vivo activities of these chemo-preventive agents, their working mechanisms, and related SARs. This will provide a better understanding of the molecular mechanism of CYP1 mediated carcinogenesis and will also give great implications for the discovery of novel chemo-preventive agents in the near future.

The immune response of a warm water fish orange-spotted grouper (Epinephelus coioides) infected with a typical cold water bacterial pathogen Aeromonas salmonicida is AhR dependent

The present study reported the first pathogenic Aeromonas salmonicida (SRW-OG1) isolated from the warm water fish orange-spotted grouper (Epinephelus coioides), and investigated the function of Aryl hydrocarbon receptor (AhR), a ligand-dependent transcriptional factor which has been recently found to be closely associated with immune response in mammals and E. coioides. Our results showed that AhR was activated by an unknown ligand in the spleen, intestine and macrophages. Meanwhile, ahr1a and ahr1b were significantly increased in the spleen, intestine and macrophages, whereas ahr2 was only increased in the intestine, which indicated that the contribution of AhR2 to the immune response may be less than that of AhR1a and AhR1b. Some key genes involved in the macrophage inflammatory response, bacterial recognition, and intestinal immunity were significantly up-regulated in the SRW-OG1 infected E. coioides. Nevertheless, declining macrophage ROS production and down-regulation of related genes were also observed, suggesting that SRW-OG1 utilized its virulence mechanisms to prevent macrophage ROS production. Furthermore, AhR inhibitor 3', 4'-DMF and the silence of ahr1a or ahr1b significantly rescued the increased IL-1β and IL-8 induced by SRW-OG1 infection, which proved that the induction of IL-1β and IL-8 in E. coioides macrophages was mediated by AhR. However, BPI/LBP, ROS production and related genes were not affected by AhR. The survival rate and immune escape rate of SRW-OG1 in the ahr1a/ahr1b knocked-down and 3', 4'-DMF treated macrophages were significantly increased compared with those in wild type macrophages. Taken together, it was preliminarily confirmed that ahr1a and ahr1b played an important role in the immune response against A. salmonicida SRW-OG1.

Hypoxia modifies the response to flutamide and linuron in male three-spined stickleback (Gasterosteus aculeatus)

Hypoxia is a major stressor in aquatic environments and it is frequently linked with excess nutrients resulting from sewage effluent discharges and agricultural runoff, which often also contain complex mixtures of chemicals. Despite this, interactions between hypoxia and chemical toxicity are poorly understood. We exposed male three-spined stickleback during the onset of sexual maturation to a model anti-androgen (flutamide; 250 μg/L) and a pesticide with anti-androgenic activity (linuron; 250 μg/L), under either 97% or 56% air saturation (AS). We assessed the effects of each chemical, alone and in combination with reduced oxygen concentration, by measuring the transcription of spiggin in the kidney, as a marker of androgen signalling, and 11 genes in the liver involved in some of the molecular pathways hypothesised to be affected by the exposures. Spiggin transcription was strongly inhibited by flutamide under both AS conditions. In contrast, for linuron, a strong inhibition of spiggin was observed under 97% AS, but this effect was supressed under reduced air saturation, likely due to interactions between the hypoxia inducible factor and the aryl hydrocarbon receptor (AhR) pathways. In the liver, hypoxia inducible factor 1α was induced following exposure to both flutamide and linuron, however this was independent of the level of air saturation. This work illustrates the potential for interactions between hypoxia and pollutants with endocrine or AhR agonist activity to occur, with implications for risk assessment and management.

Modulation of steroid metabolism and xenobiotic biotransformation responses in zebrafish (Danio rerio) exposed to triadimefon

The widely used fungicide triadimefon (TDF) has been detected in aquatic environments, and appears to disrupt steroid homeostasis; however, the toxic effects on fish reproduction triggered by TDF via the key receptor signaling pathways remain largely unknown. The present study showed that TDF (0.069, 0.138, 0.690 mg/L) exposure not only caused disordered germ cell maturation, but also decreased spawned egg production. In order to better understand this reproductive inhibition, we investigated the effects of TDF based on quantitative PCR, Western blot and mass spectrometry methodology in zebrafish. Due to the preferential accumulation of TDF in the liver, a general pattern of up-regulation of genes involved in biotransformation pathway was observed. A significant increase in abcb4 expression appeared to be responsible for TDF excretion. TDF-induced receptors (AhR2 and PXR) changed many genes involved in steroid metabolism, and subsequent disruptions in steroid homeostasis, which might be the key biological pathway in TDF reproductive toxicity. However, due to the different metabolic demands, the transcript profiles involved in steroid metabolism in zebrafish exhibited a sex-specific expression pattern. For example, the increase in gene expression of ahr2 was accompanied by a reduction in the rate of E2 biosynthesis resulting from the diminished cyp19a1a expression, and in turn led to down-regulation of esr1 and vtg1 in the liver, supporting the anti-estrogenic effect of TDF in male fish. In contrast, the increase in E2 production was accompanied by an increase in Esr1 protein expression caused by TDF and paralleled the increase in ahrr1 expression, suggesting that TDF may induce estrogenic activity through AhR-ER interactions in females. In addition, over-induction of cyp3a65 activity mediated through pxr, which helped to accelerate the transformation from TDF to triadimenol in the liver, appeared to elevate T metabolite rate in females. The down-regulation of fshβ transcript in males further suggested that TDF might adversely affect normal gametogenesis and induce reproductive toxicity.

Hepatic transcriptional profile and tissue distribution of cytochrome P450 1-3 genes in the red-crowned crane Grus japonensis

The endangered red-crowned crane (Grus japonensis) is a protected species in eastern Hokkaido and injured specimens are treated with medication. The present study aimed at understanding the expression profiles of cytochrome P450 (CYP) 1-3 genes in red-crowned crane tissues. We used 14 individuals found dead in the wild in eastern Hokkaido or in Kushiro City Zoo. Nine CYP1-3 genes expressed in the liver of the red-crowned crane were identified by high-throughput sequencing, and phylogenetically classified as CYP1A5, CYP2C23, CYP2C45, CYP2D49, CYP2G19, CYP2U1, CYP2AC1, CYP3A37, and CYP3A80. Based on the quantitative real-time PCR of 13 samples, the rank order of their median expression levels was as follows: CYP3A37 > CYP2AC1 > CYP2C45 > CYP2D49 > CYP2G19 > CYP1A5 > CYP3A80 > CYP2C23. The tissue distribution of the CYP transcripts indicated that many of the CYP1-3 genes examined were mainly expressed in the tissues where drug metabolism occurs, such as the liver, kidneys, and lungs. We found that CYP3A37 was dominant at the transcript level in the liver, indicating it might play a crucial role in liver physiology and xenobiotic metabolism. Similarly, an "orphan" CYP2AC1 was expressed at relatively high levels in the kidneys and liver, suggesting a possible role in renal and liver physiology and xenobiotic metabolism. Our results establish a foundation for future studies on red-crowned cranes aiming to further understand drug sensitivity and develop medication protocols, but also contribute to national and local projects for the conservation of red-crowned crane.

Aryl hydrocarbon receptor is required for immune response in Epinephelus coioides and Danio rerio infected by Pseudomonas plecoglossicida

Aryl hydrocarbon receptor (AhR), a ligand-dependent transcriptional factor that responds to environmental chemicals, has been recently found to be closely associated with immune response in mammals. Pseudomonas plecoglossicida (P. plecoglossicida) is a temperature-dependent bacterial pathogen of visceral white spot disease in fish. Using dual RNA-seq, we previously evaluated the expression levels of ahr1a, ahr1b, ahr2 and cyp1a in the spleen of Epinephelus coioides at different time points after infection with P. plecoglossicida. In the present study, the expression levels of ahr1a, ahr1b, ahr2 and cyp1a in different organs of E. coioides and Danio rerio showed similar trends after being infected by P. plecoglossicida. It also was noted that liver, intestine, spleen, and heart were the most obviously affected organs, and ahr2 particularly showed a dramatically increase in the spleen. Subsequently, macrophages of E. coioides were isolated, and then infected by P. plecoglossicida, followed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay, which revealed that the expression level of ahr1a in macrophages was significantly down-regulated, while expression levels of ahr1b, ahr2 and cyp1a were noticeably up-regulated. Eventually, it was noted that ahr1b and ahr2 were knocked-down in macrophages, and intracellular survival rate and immune escape rate of P. plecoglossicida were markedly improved. Taken together, ahr1a, ahr1b, ahr2 and cyp1a participate in the immune response to P. plecoglossicida in different organs of fish, while ahr1b and ahr2 may play pivotal roles in the immune response of spleen and macrophages.

Primary endometrial 3D co-cultures: A comparison between human and rat endometrium

Human and rat reproductive systems differ significantly with respect to hormonal cyclicity and endometrial cell behavior. However, species-differences in endometrial cell responses upon hormonal stimulation and exposure to potentially toxic compounds are poorly characterized. In this study, human and rat endometrial hormonal responses were assessed in vitro using a 3D co-culture model of primary human and rat endometrial cells. The models were exposed to the aryl hydrocarbon receptor (AHR) ligands 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), laquinimod, and its AHR active metabolite DELAQ. In both the human and rat endometrial models, estrogen receptor and progesterone receptor gene expression was modulated by the hormonal treatments, comparable to the in vivo situation. AHR gene expression in the human endometrial model did not change when exposed to hormones. In contrast, AHR expression decreased 2-fold in the rat model when exposed to predominantly progesterone, which resulted in a 2.8-fold attenuation of gene expression induction of cytochrome P450 1A1 (CYP1A1) by TCDD. TCDD and DELAQ, but not laquinimod, concentration-dependently induced CYP1A1 gene expression in both human and rat endometrial models. Interestingly, the relative degree of DELAQ to induce CYP1A1 was higher than that of TCDD in the human model, while it was lower in the rat model. These data clearly show species-differences in response to hormones and AHR ligands between human and rat endometrial cells in vitro, which might greatly affect the applicability of the rat as translational model for human endometrial effects. This warrants further development of human relevant, endometrium-specific test methods for risk assessment purposes.

Skeletal Muscle Interleukin-6 Regulates Hepatic Cytochrome P450 Expression: Effects of 16-Week High-Fat Diet and Exercise

High-fat diet (HFD) induces several changes to the pathways regulating energy homeostasis and changes the expression of the hepatic cytochrome p450 (Cyp) enzyme-system. Despite these pervious findings, it is still unclear how the effects of HFD and especially HFD in combination with treadmill running affect hepatic Cyp expression. In this study, we investigated the mRNA and protein expression of selected Cyp's in mice subjected to 16 weeks of HFD and treadmill running. To understand the regulatory mechanisms behind the exercise-induced reversion of the HFD-induced changes in Cyp expression, we used a model in which the exercise-induced myokine and known regulator of hepatic Cyp's, interleukin-6 (IL-6), were knocked out specifically in skeletal muscle. We found that HFD increased the mRNA expression of Cyp1a1 and Cyp4a10, and decreased the expression of Cyp2a4, Cyp2b10, Cyp2e1, and Cyp3a11. HFD in combination with treadmill running reversed the HFD increase in Cyp4a10 mRNA expression. In addition, we observed increased Cyp1a and Cyp3a protein expression as an effect of exercise, whereas Cyp2b expression was lowered as an effect of HFD. IL-6 effected the response in Cyp3a11 and Cyp1a expression. We observed no changes in the content of the aryl hydrocarbon receptor, constitutive androstane receptor, pregnane X receptor, or peroxisome proliferation activator receptor alpha. In conclusion, we show that both HFD and exercise in HFD-fed animals can regulate hepatic Cyp expression and that changes in Cyp3a in response to HFD and exercise are dependent on skeletal muscular IL-6.

Put "gender glasses" on the effects of phenolic compounds on cardiovascular function and diseases

INTRODUCTION

The influence of sex and gender is particularly relevant in cardiovascular diseases (CVD) as well as in several aspects of drug pharmacodynamics and pharmacokinetics. Anatomical and physiological differences between the sexes may influence the activity of many drugs, including the possibility of their interaction with other drugs, bioactive compounds, foods and beverages. Phenolic compounds could interact with our organism at organ, cellular, and molecular levels triggering a preventive action against chronic diseases, including CVD.

RESULTS

This article will review the role of sex on the activity of these bioactive molecules, considering the existence of sex differences in oxidative stress. It describes the pharmacokinetics of phenolic compounds, their effects on vessels, on cardiovascular system, and during development, including the role of nuclear receptors and microbiota.

CONCLUSIONS

Although there is a large gap between the knowledge of the sex differences in the phenolic compounds' activity and safety, and the urgent need for more research, available data underlie the possibility that plant-derived phenolic compounds could differently influence the health of male and female subjects.

Modulation of CYP1A1 metabolism: From adverse health effects to chemoprevention and therapeutic options

The human cytochrome P450 (CYP) 1A1 gene encodes a monooxygenase that metabolizes multiple exogenous and endogenous substrates. CYP1A1 has become infamous for its oxidative metabolism of benzo[a]pyrene and related polycyclic aromatic hydrocarbons, converting these chemicals into very potent human carcinogens. CYP1A1 expression is mainly controlled by the aryl hydrocarbon receptor (AHR), a transcription factor whose activation is induced by binding of persistent organic pollutants, including polycyclic aromatic hydrocarbons and dioxins. Accordingly, induction of CYP1A1 expression and activity serves as a biomarker of AHR activation and associated xenobiotic metabolism as well as toxicity in diverse animal species and humans. Determination of CYP1A1 activity is integrated into modern toxicological concepts and testing guidelines, emphasizing the tremendous importance of this enzyme for risk assessment and regulation of chemicals. Further, CYP1A1 serves as a molecular target for chemoprevention of chemical carcinogenesis, although present literature is controversial on whether its inhibition or induction exerts beneficial effects. Regarding therapeutic applications, first anti-cancer prodrugs are available, which require a metabolic activation by CYP1A1, and thus enable a specific elimination of CYP1A1-positive tumors. However, the application range of these drugs may be limited due to the frequently observed downregulation of CYP1A1 in various human cancers, probably leading to a reduced metabolism of endogenous AHR ligands and a sustained activation of AHR and associated tumor-promoting responses. We here summarize the current knowledge on CYP1A1 as a key player in the metabolism of exogenous and endogenous substrates and as a promising target molecule for prevention and treatment of human malignancies.

β-Naphthoflavone treatment attenuates neonatal hyperoxic lung injury in wild type and Cyp1a2-knockout mice

Exposure to supraphysiological concentrations of oxygen (hyperoxia) leads to bronchopulmonary dysplasia (BPD), one of the most common pulmonary morbidities in preterm neonates, which is more prevalent in males than females. Beta-naphthoflavone (BNF) is protective against hyperoxic lung injury in adult and neonatal wild type (WT) mice and in and mice lacking Cyp1a1gene. In this investigation, we tested the hypothesis that BNF treatment will attenuate neonatal hyperoxic lung injury in WT and Cyp1a2-/- mice, and elucidated the effect of sex-specific differences. Newborn WT or Cyp1a2-/- mice were treated with BNF (10mg/kg) or the vehicle corn oil (CO) i.p., from postnatal day (PND) 2 to 8 once every other day, while being maintained in room air or hyperoxia (85% O2) for 14days. Hyperoxia exposure lead to alveolar simplification and arrest in angiogenesis in WT as well as Cyp1a2-/- mice No significant differences were seen between WT and Cyp1a2-/- mice. Cyp1a2-/- female mice had better preservation of pulmonary angiogenesis at PND15 compared to similarly exposed males. BNF treatment attenuated lung injury and inflammation in both genotypes, and this was accompanied by a significant induction of hepatic and pulmonary CYP1A1 in WT but not in Cyp1a2-/- mice. BNF treatment increased NADPH quinone oxidoreductase (NQO1) mRNA levels in Cyp1a2-/- mouse livers compared to WT mice. These results suggest that BNF is protective in neonatal mice exposed to hyperoxia independent of CYP1A2 and this may entail the protective effect of phase II enzymes like NQO1.

Levothyroxine Replacement Improves Oxidative Status in Primary Hypothyroidism

Objective: Although hypothyroidism has been linked to oxidative stress, data regarding the relationship between thyroid hormone levels and oxidative stress is still inconsistent. This study was designed to evaluate the effect of levothyroxine replacement on oxidative stress in women with primary hypothyroidism. Design: A total of 25 female patients with primary hypothyroidism were included. Oxidative stress markers were measured before and after levothyroxine replacement treatment in all patients. Methods: Oxidative stress was evaluated through the measurement of oxidants (thiobarbituric acid reactive substances [TBARS] and nitrite/nitrate levels), and antioxidants (superoxide dismutase and catalase activity). Results: Antioxidant catalase activity (63.77 ± 23.8 vs. 50.12 ±12.75 atv/min; p = 0.03) was significantly increased and the levels of TBARS (3.02 ± 0.86 vs. 3.55 ± 0.87 μM; p = 0.03) were significantly decreased in the state of euthyroidism after levothyroxine replacement compared to the hypothyroidism before levothyroxine treatment. No significant change in neither nitrite/nitrate concentration (p = 0.18) nor in superoxide dismutase activity (p = 0.93) after L-T4 adjustment was found. Conclusions: Our data demonstrate that levothyroxine replacement improved oxidative status in patients with primary hypothyroidism, indexed by the significantly decreased levels of malonaldehyde (MDA) and increased catalase (CAT) activity.

Reuse water: Exposure duration, seasonality and treatment affect tissue responses in a model fish

Partially remediated gray (reuse) water will likely find increasing use in a variety of applications owing to the increasing scarcity of freshwater. We aimed to determine if a model fish, the goldfish, could sense reuse water using olfaction (smell), and if 30min or 7d (acute) and 60d (sub-chronic) exposures would affect their olfactory responses to natural odorants. We examined olfaction as previous studies have found that numerous chemicals can impair the olfactory sense, which is critical to carrying out numerous life-sustaining behaviors from feeding to mating. We also examined if fish olfactory and liver tissues would mount a response in terms of biotransformation enzyme gene expression, and whether treatment of reuse water with UV/H₂O₂ ameliorated adverse effects following reuse water exposure. We found that fish olfactory tissue responded to reuse water as it would to a natural odorant and that UV/H₂O₂ treatment had no influence on this. With acute exposures, olfactory impairment was apparent regardless of water type (e.g. responses of 23-55% of control), but in sub-chronic exposures, only the untreated reuse water caused olfactory impairment. The exposure of fish to reuse water increased the expression of one enzyme (CYP1A; >2.5-6.5 fold change) and reuse water treatment with UV/H₂O₂ reversed the effect. There was a seasonal effect that was likely due to changes in water quality (60d summer exposure impaired olfaction whereas spring and fall exposures did not). Overall, the data suggest that reuse water may be detected by olfaction, impair olfactory responses in fish receiving unavoidable exposures, and that exposure duration and season are important factors to consider regarding adverse effects.

Effects of the soya isoflavone genistein in early life stages of the Senegalese sole, Solea senegalensis: Thyroid, estrogenic and metabolic biomarkers

This study examines the effects induced by environmentally relevant concentrations of the isoflavone genistein (3mg/L and 10mg/L) during early life stages of the Senegalese sole. Throughout the hypothalamus-pituitary-thyroid (HPT) axis, several neurohormonal regulatory thyroid signalling patterns (thyroglobulin/Tg, thyroid peroxidase/TPO, transthyretin/TTR, thyroid receptors/TRβ, and iodothrynonine deiodinases, Dio2 and Dio3) were analysed. Furthermore, the expression patterns of estrogen receptor ERβ and haemoprotein Cyp1a were also evaluated. In the control larvae, progressive increases of constitutive hormonal signalling pathways have been evidenced from the pre-metamorphosis phase onwards, reaching the highest expression basal levels at the metamorphosis (Tg, TPO, Dio2) and/or during post-metamorphosis (TTR, TRβ, ERβ). When the early larvae were exposed to both genistein concentrations (3mg/L and 10mg/L), a statistically significant down-regulation of TPO, TTR and Tg mRNA levels was clearly detected at the metamorphic stages. In addition, the Dio2 and Dio3 transcript expression levels were also down and up-regulated when exposed to both genistein concentrations. In the larvae exposed to genistein, no statistically significant responses were recorded for the TRβ expression patterns. Nevertheless, the ERβ and Cyp1a transcript levels were up-regulated at the middle metamorphic stage (S2, at 16 dph) in the larvae exposed to high genistein concentrations and, only the ERβ was down-regulated (S1, at 12dph) at the lower doses. Finally, all these pointed out imbalances were only temporarily disrupted by exposure to genistein, since most of the modulated transcriptional signals (i.e. up or down-regulation) were quickly restored to the baseline levels. Additionally, the control and genistein-exposed Senegalese sole specimens showed characteristic ontogenetic patterns and completely suitable for an optimal development, metamorphosis, and growth.

Typical airborne quinones modulate oxidative stress and cytokine expression in lung epithelial A549 cells

Quinones that exist in ambient particulate matter (PM) are hypothesized to be associated with adverse health effects through the generation of reactive oxygen species (ROS). However, the impacts of the quinones on the inflammatory processes have yet to be clearly understood. In this study, we examined the oxidative potentials and biological effects of typical airborne quinones in the human lung epithelial A549 cells. Significant change of redox status, loss of mitochondrial membrane potentials (△Ψ) and increase of superoxide dismutase (SOD) activity were induced by exposure to quinones. Some pro-inflammatory genes including interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor (TNF-α) and monocyte chemoattractant protein-1 (MCP-1); two aromatic hydrocarbon receptor-regulated genes, cytochromes P450 1A1 (Cyp1a1) and cytochromes P450 1B1 (Cyp1b1); and oxidative stress-related gene heme oxygenase-1 (HO-1) were up-regulated after quinones treatment. Among these quinones, 1,2-naphthoquinone (1,2-NQ) up-regulated expressions of IL-6, IL-8, TNF-α, Cyp1a1, and HO-1; 2-methoxy-1,4-naphthoquinone (MNQ) up-regulated MCP-1, Cyp1b1, Cyp1a1, and HO-1; 2-methylanthraquinone (MAQ) up-regulated IL-6, IL-8, TNF-α, MCP-1, Cyp1b1, and Cyp1a1; acenaphthenequinone (ACQ) up-regulated IL-8, TNF-α, MCP-1, Cyp1b1, and Cyp1a1. These results suggested that all these five quinones had a considerable pro-inflammatory potential by inducing oxidative stress and releasing different types of cytokines/chemokines.

Pharmacokinetic Drug Interactions with Tobacco, Cannabinoids and Smoking Cessation Products

Tobacco smoke contains a large number of compounds in the form of metals, volatile gases and insoluble particles, as well as nicotine, a highly addictive alkaloid. Marijuana is the most widely used illicit drug of abuse in the world, with a significant increase in the USA due to the increasing number of states that allow medical and recreational use. Of the over 70 phytocannabinoids in marijuana, Δ9-tetrahydrocannabinol (Δ9THC), cannabidiol (CBD) and cannibinol are the three main constituents. Both marijuana and tobacco smoking induce cytochrome P450 (CYP) 1A2 through activation of the aromatic hydrocarbon receptor, and the induction effect between the two products is additive. Smoking cessation is associated with rapid downregulation of CYP1A enzymes. On the basis of the estimated half-life of CYP1A2, dose reduction of CYP1A drugs may be necessary as early as the first few days after smoking cessation to prevent toxicity, especially for drugs with a narrow therapeutic index. Nicotine is a substrate of CYP2A6, which is induced by oestrogen, resulting in lower concentrations of nicotine in females than in males, especially in females taking oral contraceptives. The significant effects of CYP3A4 inducers and inhibitors on the pharmacokinetics of Δ9THC/CBD oromucosal spray suggest that CYP3A4 is the primary enzyme responsible for the metabolism of Δ9THC and CBD. Limited data also suggest that CBD may significantly inhibit CYP2C19. With the increasing use of marijuana and cannabis products, clinical studies are needed in order to determine the effects of other drugs on pharmacokinetics and pharmacodynamics.

The Aryl Hydrocarbon Receptor in Immunity: Tools and Potential

The signaling pathway of the evolutionary old transcription factor AhR is inducible by a number of small molecular weight chemicals, including toxicants such as polycyclic aromatic hydrocarbons, bacterial toxic pigments, and physiological compounds such as tryptophan derivatives or dietary indoles. AhR activation is of immunological importance, but at the same time mediates toxicity of environmental pollutants, such as immunosuppression by dioxins. Measuring AhR activity and identification of ligands is thus of great interest for a variety of research fields. In this chapter, I briefly introduce the AhR signaling pathway, its role in immunology, and the tools and assays needed to analyze AhR signaling. Both are also needed when therapeutic applications are envisioned.

Fasting-Induced Changes in Hepatic P450 Mediated Drug Metabolism Are Largely Independent of the Constitutive Androstane Receptor CAR

Introduction

Hepatic drug metabolism by cytochrome P450 enzymes is altered by the nutritional status of patients. The expression of P450 enzymes is partly regulated by the constitutive androstane receptor (CAR). Fasting regulates the expression of both P450 enzymes and CAR and affects hepatic drug clearance. We hypothesized that the fasting-induced alterations in P450 mediated drug clearance are mediated by CAR.

Methods

To investigate this we used a drug cocktail validated in humans consisting of five widely prescribed drugs as probes for specific P450 enzymes: caffeine (CYP1A2), metoprolol (CYP2D6), omeprazole (CYP2C19), midazolam (CYP3A4) and s-warfarin (CYP2C9). This cocktail was administered to wild type (WT, C57Bl/6) mice or mice deficient for CAR (CAR^-/-) that were either fed ad libitum or fasted for 24 hours. Blood was sampled at predefined intervals and drug concentrations were measured as well as hepatic mRNA expression of homologous/orthologous P450 enzymes (Cyp1a2, Cyp2d22, Cyp3a11, Cyp2c37, Cyp2c38 and Cyp2c65).

Results

Fasting decreased Cyp1a2 and Cyp2d22 expression and increased Cyp3a11 and Cyp2c38 expression in both WT and CAR^-/- mice. The decrease in Cyp1a2 was diminished in CAR^-/- in comparison with WT mice. Basal Cyp2c37 expression was lower in CAR^-/- compared to WT mice. Fasting decreased the clearance of all drugs tested in both WT and CAR^-/- mice. The absence of CAR was associated with an decrease in the clearance of omeprazole, metoprolol and midazolam in fed mice. The fasting-induced reduction in clearance of s-warfarin was greater in WT than in CAR^-/-. The changes in drug clearance correlated with the expression pattern of the specific P450 enzymes in case of Cyp1a2-caffeine and Cyp2c37-omeprazole.

Conclusion

We conclude that CAR is important for hepatic clearance of several widely prescribed drugs metabolized by P450 enzymes. However the fasting-induced alterations in P450 mediated drug clearance are largely independent of CAR.

Skatole (3-Methylindole) Is a Partial Aryl Hydrocarbon Receptor Agonist and Induces CYP1A1/2 and CYP1B1 Expression in Primary Human Hepatocytes

Skatole (3-methylindole) is a product of bacterial fermentation of tryptophan in the intestine. A significant amount of skatole can also be inhaled during cigarette smoking. Skatole is a pulmonary toxin that induces the expression of aryl hydrocarbon receptor (AhR) regulated genes, such as cytochrome P450 1A1 (CYP1A1), in human bronchial cells. The liver has a high metabolic capacity for skatole and is the first organ encountered by the absorbed skatole; however, the effect of skatole in the liver is unknown. Therefore, we investigated the impact of skatole on hepatic AhR activity and AhR-regulated gene expression. Using reporter gene assays, we showed that skatole activates AhR and that this is accompanied by an increase of CYP1A1, CYP1A2 and CYP1B1 expression in HepG2-C3 and primary human hepatocytes. Specific AhR antagonists and siRNA-mediated AhR silencing demonstrated that skatole-induced CYP1A1 expression is dependent on AhR activation. The effect of skatole was reduced by blocking intrinsic cytochrome P450 activity and indole-3-carbinole, a known skatole metabolite, was a more potent inducer than skatole. Finally, skatole could reduce TCDD-induced CYP1A1 expression, suggesting that skatole is a partial AhR agonist. In conclusion, our findings suggest that skatole and its metabolites affect liver homeostasis by modulating the AhR pathway.

Gender-related differences in susceptibility to oxidative stress in healthy middle-aged Serbian adults

Gender-related differences in the association between polymorphism of xenobiotic-metabolising enzymes or non-genetic biomarkers and susceptibility to oxidative stress was assessed in healthy middle-aged Serbian adults, by urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG/creatinine) and total antioxidant status in serum (TAOS). Females were more susceptible to oxidative stress. In both genders, positive predictor of the antioxidative protection was serum triglyceride, while BMI <25 kg/m(2) was associated with oxidative stress. Susceptibility to oxidative stress in males was associated with GSTT1*null allele and increased serum iron, but in females, it was decreased serum bilirubin. Early identification of the risk factors could be important in the prevention of oxidative stress-related diseases.

Effects of pharmaceuticals present in aquatic environment on Phase I metabolism in fish

The fate of pharmaceuticals in aquatic environments is an issue of concern. Current evidence indicates that the risks to fish greatly depend on the nature and concentrations of the pharmaceuticals and might be species-specific. Assessment of risks associated with the presence of pharmaceuticals in water is hindered by an incomplete understanding of the metabolism of these pharmaceuticals in aquatic species. In mammals and fish, pharmaceuticals are primarily metabolized by cytochrome P450 enzymes (CYP450). Thus, CYP450 activity is a crucial factor determining the detoxification abilities of organisms. Massive numbers of toxicological studies have investigated the interactions of human pharmaceuticals with detoxification systems in various fish species. In this paper, we review the effects of pharmaceuticals found in aquatic environments on fish hepatic CYP450. Moreover, we discuss the roles of nuclear receptors in cellular regulation and the effects of various groups of chemicals on fish, presented in the recent literature.

The effects of drugs with immunosuppressive or immunomodulatory activities on xenobiotics-metabolizing enzymes expression in primary human hepatocytes

In this paper we investigated the effects of several drugs used in transplant medicine, i.e. cyclosporine A, tacrolimus, rapamycin, everolimus, mycophenolate mofetil, fluvastatin and rosuvastatin, on the expression of major drug-metabolizing enzymes in human hepatocytes. Moreover, we tested the ability of these drugs to affect transcriptional activity of glucocorticoid (GR) and aryl hydrocarbon receptor (AhR). We found that most of tested compounds did not induce expression of CYP1A1/1A2/3A4/2A6/2B6/2C9 mRNAs in human hepatocytes. Slight induction was observed for CYP2A6/2C9 mRNAs and CYP2A6 protein in the rapamycin-treated hepatocytes. Decrease of CYP2A6 and CYP2B6 proteins was observed in rosuvastatin-treated cells. Mycophenolate mofetil antagonized the effects of dexamethasone on GR but it potentiated the action of dioxin on AhR. Induction of CYP1A1 mRNA in HepG2 cells by dioxin was modestly antagonized by mycophenolate mofetil, while the induction by benzo[a]pyren or S-omeprazole was significantly potentiated by this drug. In general, tested compounds can be considered safe in the terms of possible drug-drug interaction caused by induction of drug-metabolizing cytochromes P450. Nevertheless, mycophenolate mofetil is of possible concern and its combination with drugs, environmental pollutants or food constituents, which activate AhR, may represent a significant toxicological risk.

Short-term fasting alters cytochrome P450-mediated drug metabolism in humans

Experimental studies indicate that short-term fasting alters drug metabolism. However, the effects of short-term fasting on drug metabolism in humans need further investigation. Therefore, the aim of this study was to evaluate the effects of short-term fasting (36 h) on P450-mediated drug metabolism. In a randomized crossover study design, nine healthy subjects ingested a cocktail consisting of five P450-specific probe drugs [caffeine (CYP1A2), S-warfarin (CYP2C9), omeprazole (CYP2C19), metoprolol (CYP2D6), and midazolam (CYP3A4)] on two occasions (control study after an overnight fast and after 36 h of fasting). Blood samples were drawn for pharmacokinetic analysis using nonlinear mixed effects modeling. In addition, we studied in Wistar rats the effects of short-term fasting on hepatic mRNA expression of P450 isoforms corresponding with the five studied P450 enzymes in humans. In the healthy subjects, short-term fasting increased oral caffeine clearance by 20% (P = 0.03) and decreased oral S-warfarin clearance by 25% (P < 0.001). In rats, short-term fasting increased mRNA expression of the orthologs of human CYP1A2, CYP2C19, CYP2D6, and CYP3A4 (P < 0.05), and decreased the mRNA expression of the ortholog of CYP2C9 (P < 0.001) compared with the postabsorptive state. These results demonstrate that short-term fasting alters cytochrome P450-mediated drug metabolism in a nonuniform pattern. Therefore, short-term fasting is another factor affecting cytochrome P450-mediated drug metabolism in humans.

The herbicide linuron inhibits cholesterol biosynthesis and induces cellular stress responses in brown trout

The herbicide linuron is used worldwide, and has been detected in surface waters as well as in food and drinking water. Toxicological studies have reported that linuron acts as an antiandrogen in vitro and in vivo and disrupts mammalian male reproductive function. However, global mechanisms of linuron toxicity are poorly documented. We used RNA-seq to characterize the hepatic transcriptional response of mature male brown trout exposed for 4 days to 1.7, 15.3, and 225.9 μg/L linuron. We identified a striking decrease in the expression of transcripts encoding the majority of enzymes forming the cholesterol biosynthesis pathway. We also measured a very significant decrease in total hepatic cholesterol in fish exposed to 225.9 μg/L linuron and a negative correlation between total cholesterol and linuron treatment concentration. We hypothesize that inhibition of cholesterol biosynthesis may result from the disruption of androgen signaling by linuron. Additionally, there was increased expression of a number of transcripts involved in cellular stress responses, including cyp1a (up to 560-fold), molecular chaperones, and antioxidant enzymes. We found some evidence of similar patterns of transcriptional change in fish exposed to an environmentally relevant concentration of linuron, and further research should investigate the potential for adverse effects to occur following chronic environmental exposure.

Sex-specific differences in hyperoxic lung injury in mice: role of cytochrome P450 (CYP)1A

Sex-specific differences in pulmonary morbidity in adults and preterm infants are well documented. Hyperoxia contributes to lung injury in experimental animals and humans. Cytochrome P450 (CYP) 1A enzymes have been shown to play a mechanistic role in hyperoxic lung injury (HLI) in animal models. Whether CYP1A enzymes contribute to gender-specific differences in relation to HLI is unknown. In this investigation, we tested the hypothesis that mice will display gender-specific differences in HLI, and that this phenomenon will be altered in mice lacking the genes for Cyp1a1 or 1a2. Eight week-old male and female wild type (WT) (C57BL/6J) mice, Cyp1a1-/-, and Cyp1a2-/- mice were exposed to 72h of hyperoxia (FiO2>0.95). Lung injury and inflammation were assessed and pulmonary and hepatic CYP1A1 and CYP1A2 levels were quantified at the enzyme activity, protein and mRNA level. Upon exposure to hyperoxia, liver and lung microsomal proteins showed higher pulmonary CYP1A1 (apoprotein level and activity) in WT females compared to WT males and a greater induction in hepatic CYP1A2 mRNA levels and activity in WT females after hyperoxia exposure. The gender based female advantage was lost or reversed in Cyp1a1-/- and Cyp1a2-/- mice. These findings suggest an important role for CYP1A enzymes in the gender-specific modulation of hyperoxic lung injury.

Stimulatory effect of sesamin on hepatic cytochrome P450 activities in Atlantic salmon (Salmo salar L.) is not directly associated with expression of genes related to xenobiotic metabolism

1. This study examined hepatic cytochrome P450 (CYP450) response to dietary sesamin in combination with different n-6/n-3 fatty acid ratios in fish diet. Over a period of 4 months, fish were fed seven different experimental diets an n-6/n-3 FA ratio of either 0.5 or 1.0 in combination with two sesamin levels: low sesamin = 1.16 g/kg feed and high sesamin = 5.8 g/kg feed. Control diets did not contain sesamin. 2. The CYP450-associated activities of ethoxyresorufin O-deethylase (EROD), 7-benzyloxy-4-trifluoromethylcoumarin O-debenzylation (BFCOD), pentoxyresorufin O-depentylase (PROD), coumarin hydroxylase (COH), methoxyresorufin O-deethylase (MROD) and p-nitrophenol hydroxylase (PNPH) were significantly induced by dietary sesamin in a dose-related manner. 3. Expressions of the genes CYP1A1, CYP1A3, CYP3A, AhR1α, AhR2β, AhR2δ and PXR involved in the regulation of CYP450 activities, was not the primary source of this induction.