Antioxidant Functions of the Aryl Hydrocarbon Receptor

Role of 4-Thiazolidinone-Pyrazoline/Indoline Hybrids Les-4369 and Les-3467 in BJ and A549 Cell Lines

Cancer is one of the most important problems of modern societies. Recently, studies have reported the anticancer properties of rosiglitazone related to its ability to bind peroxisome proliferator receptor γ (PPARγ), which has various effects on cancer and can inhibit cell proliferation. In this study, we investigated the effect of new 4-thiazolidinone (4-TZD) hybrids Les-4369 and Les-3467 and their effect on reactive oxygen species (ROS) production, metabolic activity, lactate dehydrogenase (LDH) release, caspase-3 activity, and gene and protein expression in human foreskin fibroblast (BJ) cells and lung adenocarcinoma (A549) cells. The ROS production and caspase-3 activity were mainly increased in the micromolar concentrations of the studied compounds in both cell lines. Les-3467 and Les-4369 increased the mRNA expression of PPARG, P53 (tumor protein P53), and ATM (ATM serine/threonine kinase) in the BJ cells, while the mRNA expression of these genes (except PPARG) was mainly decreased in the A549 cells treated with both of the tested compounds. Our results indicate a decrease in the protein expression of AhR, PPARγ, and PARP-1 in the BJ cells exposed to 1 µM Les-3467 and Les-4369. In the A549 cells, the protein expression of AhR, PPARγ, and PARP-1 increased in the treatment with 1 µM Les-3467 and Les-4369. We have also shown the PPARγ modulatory properties of Les-3467 and Les-4369. However, both compounds prove weak anticancer properties evidenced by their action at high concentrations and non-selective effects against BJ and A549 cells.

Hepatic transcriptome, transcriptional effects and antioxidant responses in Poecilia vivipara exposed to sanitary sewage

Aquatic environments are subject to threats from multiple human activities, particularly through the release of untreated sanitary sewage into the coastal environments. These effluents contain a large group of natural or synthetic compounds referred to as emerging contaminants. Monitoring the types and quantities of toxic substances in the environment, especially complex mixtures, is an exhausting and challenging task. Integrative effect-based tools, such as biomarkers, are recommended for environmental quality monitoring programs. In this study, fish Poecilia vivipara were exposed for 24 and 96 h to raw untreated sewage diluted 33 % (v/v) in order to identify hepatic genes to be used as molecular biomarkers. Through a de novo hepatic transcriptome assembly, using Illumina MiSeq, 54,285 sequences were assembled creating a reference transcriptome for this guppy species. Transcripts involved in biotransformation systems, antioxidant defenses, ABC transporters, nuclear and xenobiotic receptors were identified and evaluated by qPCR. Sanitary sewage induced transcriptional changes in AhR, PXR, CYP2K1, CYP3A30, NQO1, UGT1A1, GSTa3, GSTmu, ST1C1, SOD, ABCC1 and SOX9 genes from liver of fish, particularly after 96 h of exposure. Changes in hepatic enzyme activities were also observed. The enzymes showed differences in fish exposed to both periods, while in the gills there was a prevalence of significant results after 96 h. The observed differences were associated to gender and/or to sewage exposure. The obtained results support the use of P. vivipara as sentinel and model organism for ecotoxicological studies and evidence the importance of understanding the differential responses associated to gender.

Current state of knowledge of triclosan (TCS)-dependent reactive oxygen species (ROS) production

Triclosan (TCS) is widely used in a number of industrial and personal care products. This molecule can induce reactive oxygen species (ROS) production in various cell types, which results in diverse types of cell responses. Therefore, the aim of the present study was to summarize the current state of knowledge of TCS-dependent ROS production and the influence of TCS on antioxidant enzymes and pathways. To date, the TCS mechanism of action has been widely investigated in non-mammalian organisms that may be exposed to contaminated water and soil, but there are also in vivo and in vitro studies on plants, algae, mammalians, and humans. This literature review has revealed that mammalian organisms are more resistant to TCS than non-mammalian organisms and, to obtain a toxic effect, the effective TCS dose must be significantly higher. The TCS-dependent increase in the ROS level causes damage to DNA, protein, and lipids, which together with general oxidative stress leads to cell apoptosis or necrosis and, in the case of cancer cells, faster oncogenesis and even initiation of oncogenic transformation in normal human cells. The review presents the direct and indirect TCS action through different receptor pathways.

Impact of benzo[a]pyrene, PCB153 and sex hormones on human ESC-Derived thyroid follicles using single cell transcriptomics

INTRODUCTION

Endocrine disruptors are compounds of manmade origin able to interfere with the endocrine system and constitute an important environmental concern. Indeed, detrimental effects on thyroid physiology and functioning have been described. Differences exist in the susceptibility of human sexes to the incidence of thyroid disorders, like autoimmune diseases or cancer.

METHODS

To study how different hormonal environments impact the thyroid response to endocrine disruptors, we exposed human embryonic stem cell-derived thyroid organoids to physiological concentrations of sex hormones resembling the serum levels of human females post-ovulation or males of reproductive age for three days. Afterwards, we added 10 µM benzo[a]pyrene or PCB153 for 24 h and analyzed the transcriptome changes via single-cell RNA sequencing with differential gene expression and gene ontology analysis.

RESULTS

The sex hormones receptors genes AR, ESR1, ESR2 and PGR were expressed at low levels. Among the thyroid markers, only TG resulted downregulated by benzo[a]pyrene or benzo[a]pyrene with the "male" hormones mix. Both hormone mixtures and benzo[a]pyrene alone upregulated ribosomal genes and genes involved in oxidative phosphorylation, while their combination decreased the expression compared to benzo[a]pyrene alone. The "male" mix and benzo[a]pyrene, alone or in combination, upregulated genes involved in lipid transport and metabolism (APOA1, APOC3, APOA4, FABP1, FABP2, FABP6). The combination of "male" hormones and benzo[a]pyrene induced also genes involved in inflammation and NFkB targets. Benzo[a]pyrene upregulated CYP1A1, CYP1B1 and NQO1 irrespective of the hormonal context. The induction was stronger in the "female" mix. Benzo[a]pyrene alone upregulated genes involved in cell cycle regulation, response to reactive oxygen species and apoptosis. PCB153 had a modest effect in presence of "male" hormones, while we did not observe any changes with the "female" mix.

CONCLUSION

This work shows how single cell transcriptomics can be applied to selectively study the in vitro effects of endocrine disrupters and their interaction with different hormonal contexts.

CPX-351 exploits the gut microbiota to promote mucosal barrier function, colonization resistance, and immune homeostasis

ABSTRACT

CPX-351, a liposomal combination of cytarabine plus daunorubicin, has been approved for the treatment of adults with newly diagnosed, therapy-related acute myeloid leukemia (AML) or AML with myelodysplasia-related changes, because it improves survival and outcome of patients who received hematopoietic stem cell transplant compared with the continuous infusion of cytarabine plus daunorubicin (referred to as "7 + 3" combination). Because gut dysbiosis occurring in patients with AML during induction chemotherapy heavily affects the subsequent phases of therapy, we have assessed whether the superior activity of CPX-351 vs "7 + 3" combination in the real-life setting implicates an action on and by the intestinal microbiota. To this purpose, we have evaluated the impact of CPX-351 and "7 + 3" combination on mucosal barrier function, gut microbial composition and function, and antifungal colonization resistance in preclinical models of intestinal damage in vitro and in vivo and fecal microbiota transplantation. We found that CPX-351, at variance with "7 + 3" combination, protected from gut dysbiosis, mucosal damage, and gut morbidity while increasing antifungal resistance. Mechanistically, the protective effect of CPX-351 occurred through pathways involving both the host and the intestinal microbiota, namely via the activation of the aryl hydrocarbon receptor-interleukin-22 (IL-22)-IL-10 host pathway and the production of immunomodulatory metabolites by anaerobes. This study reveals how the gut microbiota may contribute to the good safety profile, with a low infection-related mortality, of CPX-351 and highlights how a better understanding of the host-microbiota dialogue may contribute to pave the way for precision medicine in AML.

Modulatory effects of quercetin on histological changes, biochemical and oxidative stress of rat placenta induced by inhalation exposure to crude oil vapor

The inhalation exposure to crude oil vapor (COV) has been shown to have adverse effects on the placenta and fetal development. The modulatory effects of quercetin (QUE) as a natural phenolic compound with antioxidant properties are promising for the protection of placental structure. This study aimed to investigate the modulatory role of QUE in mitigating histopathological damage, oxidative stress, and biochemical alteration in the placenta of COV-exposed pregnant rats. Forty-eight pregnant rats were divided into eight groups (days 15 and 20) as follows: 1-2) Control groups, 3-4) COV groups, 5-6) COV+QUE groups, and 7-8) QUE-treated groups (50 mg/kg). The inhalation method was used to expose pregnant rats to COV, and QUE was administered orally. On the 15th and 20th days of gestation, placental tissue was analyzed using PAS and H&E staining and immunohistochemistry. The expression of the caspase-3 gene and oxidative stress biomarkers including TAC, CAT, MDA, GPx, and SOD were investigated in the placental tissue. The COV significantly decreased the weight, diameter, and thickness of the placenta as well as the thickness of the junctional zone and labyrinth and the number of trophoblast giant cells in 15- and 20-day-old placentas (P<0.05). Also, COV significantly increased placental expression of caspase-3 and the oxidative stress biomarkers (P<0.05). The administration of QUE along with exposure to COV reduced morphometric and histological alteration, oxidative stress, and caspase-3 expression (P<0.05). Our findings indicated that QUE in COV-exposed pregnant rats can prevent placental histopathological alternations by increasing the activity of the antioxidant system.

Gene expression and trace elements in Greenlandic ringed seals (Pusa hispida)

Marine top predators such as ringed seals biomagnify environmental contaminants; and with the increasing human activities in the Arctic, ringed seals are exposed to biologically significant concentrations of trace elements resulting in reproductive impairment, immunosuppression, and neurological damages. Little is known about the molecular effects of heavy metals on these vulnerable apex predators suffering from a rapidly changing Arctic with significant loss of sea-ice. In the present study, concentrations of cadmium (Cd), mercury (Hg) and selenium (Se) were measured in liver of sixteen Greenlandic ringed seals (nine adults and seven subadults) together with molecular biomarkers involved in bio-transformation, oxidative stress, endocrine disruption and immune activity in blood and blubber. The concentrations of trace elements increased in the following order: Hg > Se > Cd with levels of mercury and selenium being highest in adults. Aryl hydrocarbon receptor nuclear translocator (ARNT), peroxisome proliferator activated receptor alpha (PPARα, estrogen receptor alpha (ESR1), thyroid hormone receptor alpha (TRα) and interleukin - 2 (IL-2) mRNA transcript levels were highest in blubber, while heat shock protein 70 (HSP70) and interleukin - 10 (IL-10) were significantly higher in blood. There were no significant correlations between the concentrations of trace elements and mRNA transcript levels suggesting that stressors other than the trace elements investigated are responsible for the changes in gene expression levels. Since Hg seems to increase in Greenlandic ringed seals, there is a need to re-enforce health monitoring of this ringed seal population.

The role of aryl hydrocarbon receptor in vitiligo: a review

Vitiligo is an acquired autoimmune dermatosis characterized by patchy skin depigmentation, causing significant psychological distress to the patients. Genetic susceptibility, environmental triggers, oxidative stress, and autoimmunity contribute to melanocyte destruction in vitiligo. Due to the diversity and complexity of pathogenesis, the combination of inhibiting melanocyte destruction and stimulating melanogenesis gives the best results in treating vitiligo. The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that can regulate the expression of various downstream genes and play roles in cell differentiation, immune response, and physiological homeostasis maintenance. Recent studies suggested that AhR signaling pathway was downregulated in vitiligo. Activation of AhR pathway helps to activate antioxidant pathways, inhibit abnormal immunity response, and upregulate the melanogenesis gene, thereby protecting melanocytes from oxidative stress damage, controlling disease progression, and promoting lesion repigmentation. Here, we review the relevant literature and summarize the possible roles of the AhR signaling pathway in vitiligo pathogenesis and treatment, to further understand the links between the AhR and vitiligo, and provide new potential therapeutic strategies.

Disrupting Development: Unraveling the Interplay of Aryl Hydrocarbon Receptor (AHR) and Wnt/β-Catenin Pathways in Kidney Development Under the Influence of Environmental Pollutants

Understanding the intricate molecular mechanisms governing aryl hydrocarbon receptor (AHR) and Wnt/β-Catenin pathways crosstalk is of paramount importance for elucidating normal development. We investigated the repercussions of aberrant activation of these signaling pathways on kidney development. HEK-293 cells were subjected to AHR and Wnt activators and inhibitors for 3 and 24 h. Subsequently, pregnant adult female BALB/c mice were administered treatments at gestation day 9 (GD-9), and embryos were analyzed at GD-18 using a combination of cellular, molecular, stereological, and histopathological techniques. Our results demonstrated a noteworthy escalation in oxidative stress and gene expression endpoints associated with apoptosis. Moreover, stereological analyses exhibited alterations in cortex, proximal tubule, and kidney tissue vessels volumes. Remarkably, co-treatment with 6-formylindolo [3,2-b] carbazole (FICZ) and cadmium (Cd) resulted in a significant reduction in glomerulus volume, while elevating the volumes of distal tubule, Henle loop, and connective tissue, compared to the control group. Histopathological investigations further confirmed structural changes in the loop of Henle and proximal tubule, alongside a decline in glomerular volume. Additionally, the expression levels of AHR and Ctnnb1 genes significantly increased in the Cd-treated group compared to the control group. Enhanced expression of apoptosis-related genes, including Bcl-x, Bax, and Caspase3, along with alterations in mitochondrial membrane potential and cytochrome C release, was observed. In contrast, Gsk3 gene expression was significantly decreased. Our findings robustly establish that chemical pollutants, such as Cd, disrupt the AHR and Wnt/β-Catenin physiological roles during developmental stages by inhibiting the metabolic degradation of FICZ.

Exploring aryl hydrocarbon receptor (AhR) as a target for Bisphenol-A (BPA)-induced pancreatic islet toxicity and impaired glucose homeostasis: Protective efficacy of ethanol extract of Centella asiatica

The estrogenic impact of Bisphenol-A (BPA), a widely recognized endocrine disruptor, causes disruption of pancreatic β-cell function through estrogen receptors (ERs). While BPA's binding affinity for ERs is significantly lower than that of its natural counterpart, estrogen, recent observations of BPA's affinity for aryl hydrocarbon receptor (AhR) in specific cellular contexts have sparked a specific question: does AhR play a role in BPA's toxicological effects within the endocrine pancreas? To explore this question, we investigated BPA's (10 and 100 μg/ kg body weight/day for 21 days) potential to activate AhR within pancreatic islets and assessed the protective role of ethanol extract of Centella asiatica (CA) (200 and 400 mg/kg body weight/day for 21 days) against BPA-mediated toxicity in mouse model. Our results indicate that BPA effectively triggers the activation of AhR and modulates its target genes within pancreatic islets. In contrast, CA activates AhR but directs downstream pathways differentially and activates Nrf2. Additionally, CA was observed to counteract the disruption caused by BPA in glucose homeostasis and insulin sensitivity. Furthermore, BPA-induced oxidative stress and exaggerated production of proinflammatory cytokines were effectively counteracted by CA supplementation. In summary, our study suggests that CA influenced AhR signaling to mitigate the disrupted pancreatic endocrine function in BPA exposed mice. By shedding light on how BPA interacts with AhR, our research provides valuable insights into the mechanisms involved in the diabetogenic actions of BPA.

Gut microbiota metabolites, redox status, and the related regulatory effects of probiotics

Oxidative stress is a state of imbalance between oxidation and antioxidation. It is caused by excess levels of free radicals and leads to the damage of DNA, proteins, and lipids. The crucial role of gut microbiota in regulating oxidative stress has been widely demonstrated. Studies have suggested that the redox regulatory effects of gut microbiota are related to gut microbiota metabolites, including fatty acids, lipopolysaccharides, tryptophan metabolites, trimethylamine-N-oxide and polyphenolic metabolites. In recent years, the potential benefits of probiotics have been gaining increasing scientific interest owing to their ability to modulate gut microbiota and oxidative stress. In this review, we summarise the adverse health effects of oxidative stress and discuss the role of the gut microbiota and its metabolites in redox regulation. Based on the influence of gut microbiota metabolites, the roles of probiotics in preventing oxidative stress are highlighted.

Fecal microbiota transplantation improves hepatic fibro-inflammation via regulating oxidative stress in experimental NASH

Nonalcoholic steatohepatitis (NASH) is associated with imbalance of gut microbiome, indicating participation of gut environment in hepatic health status. Therefore, modulating gut environment via fecal microbiota transplantation (FMT) is a promising therapeutic procedure for NASH patients. However, the effect and mechanism of the FMT remains largely unknown. Here, we investigated the gut-liver axis to understand the FMT-mediated hepatic improvement in NASH. Feces from specific pathogen free mice were infused allogeneically into gastrointestinal tract of mice fed with high fat, high cholesterol and fructose (HFHCF), resulting in suppressing hepatic pathogenic events, featured by decreasing inflammatory and fibrotic mediators. The FMT elevated NF-E2-related factor 2 (NRF2), a key transcription factor that regulates antioxidant enzymes, in livers. The HFHCF-induced NASH increased intestinal permeability with abundant Facklamia and Aerococcus, an imbalanced gut environment that was significantly improved by the FMT, characterized with restoration of intestinal barrier function and an enrichment of Clostridium. Notably, the gut environment created by FMT was inferred to produce metabolites from the aromatic biogenic amine degradation pathway, specifically 4-hydroxyphenylacetic acid (4-HPA), which is known to ameliorate liver injury. We suggest that gut-derived molecules, related to hepatic improvement such as 4-HPA are the potential therapeutic agents for preventing and treating NASH.

Protective effect of quercetin on fetal development and congenital skeletal anomalies against exposure of pregnant Wistar rats to crude oil vapor

BACKGROUND

Epidemiological evidence indicates a relationship between maternal exposure to crude oil vapors (COV) during pregnancy and adverse pregnancy outcomes. Quercetin (QUE) is a plant flavonoid with purported antioxidant and anti-inflammatory effects, which has been shown to prevent birth defects. This study was aimed to investigate the protective role of QUE on fetal development and congenital skeletal anomalies caused by exposure of pregnant rats to COV.

METHODS

Twenty-four pregnant Wistar rats were randomly categorized into four groups of control, COV, COV + QUE, and QUE (50 mg/kg). The inhalation method was used to expose pregnant rats to COV from day 0 to 20 of pregnancy, and QUE was administered orally during this period. On day 20 of gestation, the animals were anesthetized and a laparotomy was performed, and then the weight and crown rump length (CRL) of the fetuses were determined. Skeletal stereomicroscopic evaluations of fetuses were performed using Alcian blue/Alizarin red staining method, and the expression of osteogenesis-related genes (Runx2 and BMP-4) was evaluated using qPCR.

RESULTS

This study showed that prenatal exposure to COV significantly reduced fetal weight and CRL, and expression of Runx2 and BMP-4 genes. Moreover, COV significantly increased the incidence of congenital skeletal anomalies such as cleft palate, spina bifida and non-ossification of the fetal bones. However, administration of QUE with exposure to COV improved fetal bone development and reduced congenital skeletal anomalies.

CONCLUSION

QUE can ameliorate the teratogenic effects of prenatal exposure to COV by increasing the expression of osteogenesis-related genes.

Effect of N-Carbamylglutamate Supplementation on Growth Performance, Jejunal Morphology, Amino Acid Transporters, and Antioxidant Ability of Weaned Pigs

Weaning is an important period that affects the performance of piglets. However, the regulation of dietary amino acid levels is considered to be an effective way to alleviate the weaning stress of piglets. N-carbamylglutamate (NCG) plays an important role in improving the growth performance and antioxidant capacity of animals. A total of 36 weaned piglets were randomly assigned to two treatment groups, a control group (CON) and a 500 mg/kg NCG group (NCG), and the experiment lasted for 28 days. The results show that the NCG treatment group showed an increased 0-28 days average weight gain and average daily feed intake, and also increased contents of GLU and HDL, and lower SUN in serum, and an upregulation of the expression of the amino acid transporters SNAT2, EAAC1, SLC3A1, and SLC3A2 mRNA in the jejunum (p < 0.05), as well as an increased villus length and VH:CD ratio, and claudin-1, occludin, and ZO-1 mRNA expression in the jejunum (p < 0.05). The NCG treatment group showed an increased content of GSH-Px in serum and T-AOC and SOD in the jejunum, and a lower content of MDA (p < 0.05); and the upregulation of the mRNA expression related to antioxidant enzymes (CAT, SOD1, Gpx4, GCLC, GCLM and Nrf2, AhR, CYP1A1) in the jejunal mucosa (p < 0.05). In addition, compared with the control group, the NCG treatment group saw an upregulation in the mRNA expression of IL-10 and a decrease in the expression of IL-1β and IL-4 in the jejunal mucosa (p < 0.05). In summary, the results of this study suggest that NCG improved growth performance and jejunal morphology, improved the jejunal transport of amino acids related to the ornithine cycle, and improved the antioxidant capacity in weaned pigs.

Inhalation exposure to crude oil vapor induces behavioural deficits by increasing oxidative stress and histopathological changes in rat hippocampus: Quercetin therapeutic approach

OBJECTIVE

Inhalation exposure to crude oil vapor (COV) and petroleum products is considered responsible for neurobehavioral toxicity in human and animal models. The antioxidant activity of quercetin (Que) and its derivatives are promising for protecting the hippocampus. This study aimed to evaluate the neuroprotective role of Que against COV-induced behavioral alterations and hippocampus damage.

METHODS

Eighteen adult male Wistar rats were randomly divided into the following three groups (n = 6): the control, the COV, and the COV + Que group. The inhalation method was used to expose the rats to crude oil vapors for 5 h daily, and Que (50 mg/kg) was administered orally. After 30 days of treatment, the spatial working memory and anxiety levels were evaluated using the cross-arm maze and elevated plus maze (EPM), respectively. TUNEL assay and hematoxylin-eosin (H&E) staining were used to identify the necrosis, normal and apoptotic cells in the hippocampus. Moreover, the levels of oxidative stress biomarkers including malondialdehyde (MDA), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (TAC) were investigated in the hippocampus tissue.

RESULTS

The results indicated that exposure to COV was associated with a significant decrease in spatial working memory and activity of CAT, TAC, SOD, and GPx enzymes compared to the control (P < 0.05). Moreover, COV significantly increased the level of anxiety, MDA, and hippocampal apoptosis (P < 0.05). The simultaneous administration of quercetin along with exposure to COV improved the behavioral alterations, activity of antioxidant enzymes, and hippocampal apoptosis.

CONCLUSIONS

These findings suggest that quercetin prevents COV-induced hippocampal damage by enhancing the antioxidant system and preventing cell apoptosis.

Lemon-derived nanovesicles achieve antioxidant and anti-inflammatory effects activating the AhR/Nrf2 signaling pathway

In the last years, extracellular vesicles (EVs) from different plant matrices have been isolated and gained the interest of the scientific community for their intriguing biological properties. In this study, we isolated and characterized nanovesicles from lemon juice (LNVs) and evaluated their antioxidant effects. We tested LNV antioxidant activity using human dermal fibroblasts that were pre-treated with LNVs for 24 h and then stimulated with hydrogen peroxide (H₂O₂) and UVB irradiation. We found that LNV pre-treatment reduced ROS levels in fibroblasts stimulated with H₂O₂ and UVB. This reduction was associated with the activation of the AhR/Nrf2 signaling pathway, whose protein expression and nuclear localization was increased in fibroblasts treated with LNVs. By using zebrafish embryos as in vivo model, we confirmed the antioxidant effects of LNVs. We found that LNVs reduced ROS levels and neutrophil migration in zebrafish embryos stimulated with LPS.

Neuroprotective and nephroprotective effects of Ircinia sponge in polycyclic aromatic hydrocarbons (PAHs) induced toxicity in animal model: a pharmacological and computational approach

The present study investigated the neuroprotective and nephroprotective effects of the sponge Ircinia sp. ethyl acetate extract (ISPE) against persistent aromatic pollutants in vitro and in vivo. Different exponential experimental assays were applied to this study. An in vitro study to investigate the potential therapeutic effect of ISPE using antioxidants (for example, ABTS and DPPH) and anti-Alzheimer assays (inhibition of acetylcholinesterase); the in-vivo study was designed to evaluate the protective effect of ISPE as neuroprotective and nephroprotective against the destructive effect of PAH. Several assays included oxidative assays (LPO), antioxidant biomarkers (GSH, GST), and inflammatory and neurodegenerative biomarkers (PTK,SAA). Additionally, the results were confirmed using histopathological examination. The in silico screening study improved the in vitro and in vivo findings through interaction between the aryl hydrocarbon receptor (AHR) and the polyphenolic content of ISPE extract, which was determined using LCMSM. The results and discussion showed that ISPE exhibited a promising antioxidant and anti-acetylcholinesterase activity as evidenced by IC₅₀ values of 49.74, 28.25, and 0.18 µg/mL in DPPH, ABTS, and acetylcholinesterase inhibition assays, respectively. In vivo, the study showed that animals receiving ISPE before poly aromatic hydrocarbons administration PAHs (Prot, ISPE) showed significant amelioration in kidney functions manifested by the reduction of serum urea, uric acid, and creatinine by 40.6%, 66.4%, and 134.8%, respectively, concerning PAH-injected mice (HAA). Prot, ISPE revealed a decline in malondialdehyde (MDA) and total proteins (TP) in kidney and brain tissues by 73.63% and 50.21%, respectively, for MDA and 59.82% and 80.41%, respectively, for TP with respect to HAA. Prot, ISPE showed significant elevation in reduced glutathione (GSH) and glutathione transferase (GST) in kidney and brain tissues and reduction in the inflammatory and pre-cancerous biomarkers, namely, serum protein tyrosine kinases (PTKs) and serum amyloid A (SAA). These findings were further supported by histopathological examination of kidney and brain tissues, which revealed normal structure approaching normal control. Metabolic profiling of ISPE using LC-MS-MS showed the presence of fourteen polyphenolic compounds belonging mainly to phenolic acids and flavonoids. In silico study revealed that all the tested compounds exerted certain binding with the aryl hydrocarbon receptor, where rutin showed the best fitting (ΔG =  - 7.6 kcal/mol^-1) with considerable pharmacokinetic and pharmacodynamic properties revealed from in silico ADME (Absorption, Distribution, Metabolism, and Excretion) study. Hence, it can be concluded that the Ircinia sponge showed a promising protective effect versus kidney and brain toxicity triggered by PAHs.

Improving hydrocarbon toxicity tolerance in poultry: role of genes and antioxidants

Sustenance of smallholder poultry production as an alternative source of food security and income is imperative in communities exposed to hydrocarbon pollution. Exposure to hydrocarbon pollutants causes disruption of homeostasis, thereby compromising the genetic potential of the birds. Oxidative stress-mediated dysfunction of the cellular membrane is a contributing factor in the mechanism of hydrocarbon toxicity. Epidemiological studies show that tolerance to hydrocarbon exposure may be caused by the activation of genes that control disease defense pathways like aryl hydrocarbon receptor (AhR) and nuclear factor erythroid 2p45-related factor 2 (Nrf2). Disparity in the mechanism and level of tolerance to hydrocarbon fragments among species may exist and may result in variations in gene expression within individuals of the same species upon exposure. Genomic variability is critical for adaptation and serves as a survival mechanism in response to environmental pollutants. Understanding the interplay of diverse genetic mechanisms in relation to environmental influences is important for exploiting the differences in various genetic variants. Protection against pollutant-induced physiological responses using dietary antioxidants can mitigate homeostasis disruptions. Such intervention may initiate epigenetic modulation relevant to gene expression of hydrocarbon tolerance, enhancing productivity, and possibly future development of hydrocarbon-tolerant breeds.

Effect of allyl isothiocyanate on oxidative stress in COPD via the AhR / CYP1A1 and Nrf2 / NQO1 pathways and the underlying mechanism

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is currently the third leading cause of death globally. Oxidative stress affects various molecular mechanisms and is the main driving factor of COPD. Ally isothiocyanate (AITC) is an effective component of Semen Sinapis Albae, which has favorable effects for the treatment of COPD, but its mechanism has not been fully elucidated.

PURPOSE

This study aimed to elucidate the antioxidant effect of AITC on COPD and its molecular mechanism, and preliminarily determine the role of AhR in the progression of COPD.

STUDY DESIGN

The COPD rat model was established by smoking combined with intratracheal instillation of lipopolysaccharide. Different doses of AITC, positive control drug acetylcysteine, AhR inhibitor alpha-naphthoflavone, and agonist beta-naphthoflavone were administered by gavage. Human bronchial epithelial cells induced by cigarette smoke extract (CSE) were used in an in vitro model to explore the molecular mechanisms of AITC.

METHODS

The effects of AITC on lung function and oxidative stress in rats were evaluated in vivo using the respiratory function test, white blood cell count, enzyme-linked immunosorbent assay, and histological staining. The changes in protein expression in the lung tissue were detected by immunohistochemistry and Western blotting. RT-PCR, western blotting, and immunofluorescence were used to explore the molecular mechanisms of AITC. Enzyme-linked immunosorbent assay, reactive oxygen species probing, and flow cytometry were used to determine the antioxidant effect of AITC.

RESULTS

AITC can improve the lung function of rats with COPD, restore lung tissue structure, improve oxidative stress, reduce inflammation, and inhibit lung cell apoptosis. AITC reversed the upregulation of AhR and CYP1A1 and the down-regulation of Nrf2 and NQO1 in the lung tissues of rats with COPD. CSE stimulation can increase the expressions of AhR and CYP1A1 and decrease the expressions of Nrf2 and NQO1 in 16HBE cells, leading to severe oxidative stress and inflammatory response and, ultimately, apoptosis. AITC inhibited AhR and CYP1A1 expressions, induced Nrf2 and NQO1 expressions, promoted Nrf2 nuclear translocation, and improved CSE-induced toxicological effects.

CONCLUSION

AITC may improve lung oxidative stress by inhibiting the AhR / CYP1A1 and activating the Nrf2 / NQO1 pathways, thereby delaying the pathological progression of COPD.

Tanshinone IIA suppresses burning incense-induced oxidative stress and inflammatory pathways in astrocytes

The burning incense (BI) behavior could be widely observed in Asia families. Incense sticks are often believed to be made from natural herbs and powders, and to have minimal impact on human health; however, there is limited research to support this claim. The current study aimed to identify the components of BI within the particulate matter 2.5 µm (PM_2.5) range and explore if BI has bio-toxicity effects on rat astrocytes (CTX-TNA2). The study also examined the protective effects and underlying molecular mechanisms of tanshinone IIA, a primary lipid-soluble compound found in the herb danshen (Salvia miltiorrhiza Bunge), which has been shown to benefit the central nervous system. Results showed that despite the differences in BI components compared to the atmospheric particulate matter (PM) standards, BI still had a bio-toxicity on astrocytes. BI exposure caused early and late apoptosis, reactive oxygen species (ROS) production, MAPKs (JNK, p38, and ERK), and Akt signaling activation, and inflammation-related proteins (cPLA2, COX-2, HO-1, and MMP-9) increases. Our results further exhibit that the tanshinone IIA pre-treatment could significantly avoid the BI-induced apoptosis and inflammatory signals on rat astrocytes. These findings suggest that BI exposure may cause oxidative stress in rat astrocytes and increase inflammation-related proteins and support the potential of tanshinone IIA as a candidate for preventing BI-related adverse health effects.

Machine learning study: from the toxicity studies to tetrahydrocannabinol effects on Parkinson's disease

Aim: Investigating molecules having toxicity and chemical similarity to find hit molecules. Methods: The machine learning (ML) model was developed to predict the arylhydrocarbon receptor (AHR) activity of anti-Parkinson's and US FDA-approved drugs. The ML algorithm was a support vector machine, and the dataset was Tox21. Results: The ML model predicted apomorphine in anti-Parkinson's drugs and 73 molecules in FDA-approved drugs as active. The authors were curious if there is any molecule like apomorphine in these 73 molecules. A fingerprint similarity analysis of these molecules was conducted and found tetrahydrocannabinol (THC). Molecular docking studies of THC for dopamine receptor 1 (affinity = -8.2 kcal/mol) were performed. Conclusion: THC may affect dopamine receptors directly and could be useful for Parkinson's disease.

Dietary patterns, lung function and asthma in childhood: a longitudinal study

BACKGROUND

Longitudinal epidemiological data are scarce examining the relationship between dietary patterns and respiratory outcomes in childhood. We investigated whether three distinct dietary patterns in mid-childhood were associated with lung function and incident asthma in adolescence.

METHODS

In the Avon Longitudinal Study of Parents and Children, 'processed', 'traditional', and 'health-conscious' dietary patterns were identified using principal components analysis from food frequency questionnaires at 7 years of age. Post-bronchodilator forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and forced expiratory flow at 25-75% of FVC (FEF25-75) were measured at 15.5 years and were transformed to z-scores based on the Global Lung Function Initiative curves. Incident asthma was defined by new cases of doctor-diagnosed asthma at age 11 or 14 years.

RESULTS

In multivariable-adjusted models, the 'health-conscious' pattern was positively associated with FEV1 (regression coefficient comparing top versus bottom quartile of pattern score 0.16, 95% CI 0.01 to 0.31, P for trend 0.04) and FVC (0.18, 95% CI 0.04 to 0.33, P for trend 0.02), while the 'processed' pattern was negatively associated with FVC (- 0.17, 95% CI - 0.33 to - 0.01, P for trend 0.03). Associations between the 'health-conscious' and 'processed' patterns and lung function were modified by SCGB1A1 and GPX4 gene polymorphisms. We found no evidence of an association between the 'traditional' pattern and lung function, nor between any pattern and FEF25-75 or incident asthma.

CONCLUSIONS

A 'health-conscious' diet in mid-childhood was associated with higher subsequent lung function, while a diet high in processed food was associated with lower lung function.

Is it really safe to replace decabromodiphenyl ether (BDE209) with decabromodiphenyl ethane (DBDPE)?: A perspective from hepatotoxicity

In this paper, the hepatocytotoxicity and aryl hydrocarbon receptor (AHR) activity of decabromodiphenyl ethane (DBDPE), decabromodiphenyl ether (BDE209) and other 18 analogues were evaluated in vitro using human normal liver cell L02. These dioxin-like compounds showed differential hepatocytotoxicity (EC₅₀  = 0.38-17.87 mg/L) and AHR activity (EROD activity = 4.53-46.35 U/μg). In silico study indicated the distance of π-π bonds between the benzene ring of compounds and residue Phe234 of AHR played a key role in the binding of AHR, and the substituents on the benzene ring also influenced the activity. Combining molecular biology and bioomics, the comprehensive investigations on the hepatotoxic mechanisms have demonstrated the AHR signaling pathway was the key mediation mechanism for the hepatotoxicity of DBDPE/BDE209. The cytochrome P450s (CYP2 family) mediated formation of reactive oxygenated intermediates might be the dominant toxic mechanism, which could produce oxidative stress or cause genotoxicity. Although the experimental toxicity of DBDPE was smaller relative to BDE209, the health risk of DBDPE may be much greater than we expected, due to the high potential to form a variety of dioxin-like intermediates by microbial oxidation of ethyl group. Therefore, whether it is really safe to replace BDE209 with DBDPE is a debatable question, and more ecotoxicological and health data are needed to clarify this issue.

Functions of the aryl hydrocarbon receptor (AHR) beyond the canonical AHR/ARNT signaling pathway

The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor regulating adaptive and maladaptive responses toward exogenous and endogenous signals. Research from various biomedical disciplines has provided compelling evidence that the AHR is critically involved in the pathogenesis of a variety of diseases and disorders, including autoimmunity, inflammatory diseases, endocrine disruption, premature aging and cancer. Accordingly, AHR is considered an attractive target for the development of novel preventive and therapeutic measures. However, the ligand-based targeting of AHR is considerably complicated by the fact that the receptor does not always follow the beaten track, i.e. the canonical AHR/ARNT signaling pathway. Instead, AHR might team up with other transcription factors and signaling molecules to shape gene expression patterns and associated physiological or pathophysiological functions in a ligand-, cell- and micromilieu-dependent manner. Herein, we provide an overview about some of the most important non-canonical functions of AHR, including crosstalk with major signaling pathways involved in controlling cell fate and function, immune responses, adaptation to low oxygen levels and oxidative stress, ubiquitination and proteasomal degradation. Further research on these diverse and exciting yet often ambivalent facets of AHR biology is urgently needed in order to exploit the full potential of AHR modulation for disease prevention and treatment.

Cannabidiol mediates epidermal terminal differentiation and redox homeostasis through aryl hydrocarbon receptor (AhR)-dependent signaling

BACKGROUND

Cannabidiol, a non-psychoactive phytocannabinoid, has antioxidant and anti-inflammatory activity in keratinocytes. However, the signaling pathway through which cannabidiol exerts its effect on keratinocytes or whether it can modulate keratinocyte differentiation has not been fully elucidated yet.

OBJECTIVE

We investigated whether cannabidiol modulates epidermal differentiation and scavenges reactive oxygen species through the aryl hydrocarbon receptor (AhR) in keratinocytes and epidermal equivalents.

METHODS

We investigated the cannabidiol-induced activation of AhR using AhR luciferase reporter assay, qRT-PCR, western blot, and immunofluorescence assays. We also analyzed whether keratinocyte differentiation and antioxidant activity are regulated by cannabidiol-induced AhR activation.

RESULTS

In both keratinocytes and epidermal equivalents, cannabidiol increased both the mRNA and protein expression of filaggrin, involucrin, NRF2, and NQO1 and the mRNA expression of the AhR target genes, including CYP1A1 and aryl hydrocarbon receptor repressor. Additionally, cannabidiol showed antioxidant activity that was attenuated by AhR knockdown or co-administration with an AhR antagonist. Moreover, cannabidiol increased the ratio of OVOL1/OVOL2 mRNA expression, which is a downstream regulator of AhR that mediates epidermal differentiation. In addition to increased expression of barrier-related proteins, cannabidiol-treated epidermal equivalent showed a more prominent granular layer than the control epidermis. The increased granular layer by cannabidiol was suppressed by the AhR antagonist.

CONCLUSION

Cannabidiol can be a modulator of the AhR-OVOL1-filaggrin axis and AhR-NRF2-NQO1 signaling, thus indicating a potential use of cannabidiol in skin barrier enhancement and reducing oxidative stress.

Cap 'n' Collar C and Aryl Hydrocarbon Receptor Nuclear Translocator Facilitate the Expression of Glutathione S-Transferases Conferring Adaptation to Tannic Acid and Quercetin in Micromelalopha troglodyta (Graeser) (Lepidoptera: Notodontidae)

Micromelalopha troglodyta (Graeser) (Lepidoptera: Notodontidae) is a notorious pest of poplar. Coevolution with poplars rich in plant secondary metabolites prompts M. troglodyta to expand effective detoxification mechanisms against toxic plant secondary metabolites. Although glutathione S-transferases (GSTs) play an important role in xenobiotic detoxification in M. troglodyta, it is unclear how GSTs act in response to toxic secondary metabolites in poplar. In this study, five GST gene core promoters were accurately identified by a 5' loss luciferase reporter assay, and the core promoters were significantly induced by two plant secondary metabolites in vitro. Two transcription factors, cap 'n' collar C (CncC) and aryl hydrocarbon receptor nuclear translocator (ARNT), were cloned in M. troglodyta. MtCncC and MtARNT clustered well with other insect CncCs and ARNTs, respectively. In addition, MtCncC and MtARNT could bind the MtGSTt1 promoter and strongly improve transcriptional activity, respectively. However, MtCncC and MtARNT had no regulatory function on the MtGSTz1 promoter. Our findings revealed the molecular mechanisms of the transcription factors MtCncC and MtARNT in regulating the GST genes of M. troglodyta. These results provide useful information for the control of M. troglodyta.

Kynurenine/Aryl Hydrocarbon Receptor Modulates Mitochondria-Mediated Oxidative Stress and Neuronal Apoptosis in Experimental Intracerebral Hemorrhage

Aims: Oxidative stress and neuronal apoptosis play crucial roles in the pathological processes of secondary injury after intracerebral hemorrhage (ICH). Aryl hydrocarbon receptor (AHR), together with its endogenous ligand kynurenine, is known to mediate free radical accumulation and neuronal excitotoxicity in central nervous systems. Herein, we investigate the pathological roles of kynurenine/AHR after ICH. Results: Endogenous AHR knockout alleviated reactive oxygen species accumulation and neuronal apoptosis in ipsilateral hemisphere at 48 h after ICH in mice. The ICH insult resulted in an increase of total and nucleus AHR protein levels and AHR transcriptional activity. Inhibition of AHR provided both short- and long- term neurological benefits by attenuating mitochondria-mediated oxidative stress and neuronal apoptosis after ICH in mice. RhoA-Bax signaling activated mitochondrial death pathway and participated in deleterious actions of AHR. Finally, we reported that exogenous kynurenine aggravated AHR activation and mediated the brain mentioned earlier. Male animals were used in the experiments. Innovation: We show for the first time that kynurenine/AHR mediates mitochondria death and free radical accumulation, at least partially via the RhoA/Bax signaling pathway. Pharmacological antagonists of AHR and kynurenine may ameliorate neurobehavioral function and improve the prognosis of patients with ICH. Conclusion: Kynurenine/AHR may serve as a potential therapeutic target to attenuate mitochondria-mediated oxidative stress and neuronal cells impairment in patients with ICH. Antioxid. Redox Signal. 37, 1111-1129.

Insight into the physiological and pathological roles of the aryl hydrocarbon receptor pathway in glucose homeostasis, insulin resistance, and diabetes development

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcriptional factor that mediates the toxicities of several environmental pollutants. Decades of research have been carried out to understand the role of AhR as a novel mechanism for disease development. Its involvement in the pathogenesis of cancer, cardiovascular diseases, rheumatoid arthritis, and systemic lupus erythematosus have long been known. One of the current hot research topics is investigating the role of AhR activation by environmental pollutants on glucose homeostasis and insulin secretion, and hence the pathogenesis of diabetes mellitus. To date, epidemiological studies have suggested that persistent exposure to environmental contaminants such as dioxins, with subsequent AhR activation increases the risk of specific comorbidities such as obesity and diabetes. The importance of AhR signaling in various molecular pathways highlights that the role of this receptor is far beyond just xenobiotic metabolism. The present review aims at providing significant insight into the physiological and pathological role of AhR and its regulated enzymes, such as cytochrome P450 1A1 (CYP1A1) and CYP1B1 in both types of diabetes. It also provides a comprehensive summary of the current findings of recent research studies investigating the role of the AhR/CYP1A1 pathway in insulin secretion and glucose hemostasis in the pancreas, liver, and adipose tissues. This review further highlights the molecular mechanisms involved, such as gluconeogenesis, hypoxia-inducible factor (HIF), oxidative stress, and inflammation.

Sub-toxic events induced by truck speed-facilitated PM2.5 and its counteraction by epigallocatechin-3-gallate in A549 human lung cells

To distinguish the influences of fuel type and truck speed on chemical composition and sub-toxic effects of particulates (PM2.5) from engine emissions, biomarkers-interleukin-6 (IL-6), cytochrome P450 (CYP) 1A1, heme oxygenase (HO)-1, and NADPH-quinone oxidoreductase (NQO)-1-were studied in A549 human lung cells. Fuel type and truck speed preferentially affected the quantity and ion/polycyclic aromatic hydrocarbon (PAH) composition of PM2.5, respectively. Under idling operation, phenanthrene was the most abundant PAH. At high speed, more than 50% of the PAHs had high molecular weight (HMW), of which benzo[a]pyrene (B[a]P), benzo[ghi]perylene (B[ghi]P), and indeno[1,2,3-cd]pyrene (I[cd]P) were the main PAHs. B[a]P, B[ghi]P, and I[cd]P caused potent induction of IL-6, CYP1A1, and NQO-1, whereas phenanthrene mildly induced CYP1A1. Based on the PAH-mediated induction, the predicted increases in biomarkers were positively correlated with the measured increases. HMW-PAHs contribute to the biomarker induction by PM2.5, at high speed, which was reduced by co-exposure to epigallocatechin-3-gallate.

Aryl hydrocarbon receptor (AhR) reveals evidence of antagonistic pleiotropy in the regulation of the aging process

The antagonistic pleiotropy hypothesis is a well-known evolutionary theory to explain the aging process. It proposes that while a particular gene may possess beneficial effects during development, it can exert deleterious properties in the aging process. The aryl hydrocarbon receptor (AhR) has a significant role during embryogenesis, but later in life, it promotes several age-related degenerative processes. For instance, AhR factor (i) controls the pluripotency of stem cells and the stemness of cancer stem cells, (ii) it enhances the differentiation of embryonal stem cells, especially AhR signaling modulates the differentiation of hematopoietic stem cells and progenitor cells, (iii) it also stimulates the differentiation of immunosuppressive Tregs, Bregs, and M2 macrophages, and finally, (iv) AhR signaling participates in the differentiation of many peripheral tissues. On the other hand, AhR signaling is involved in many processes promoting cellular senescence and pathological processes, e.g., osteoporosis, vascular dysfunction, and the age-related remodeling of the immune system. Moreover, it inhibits autophagy and aggravates extracellular matrix degeneration. AhR signaling also stimulates oxidative stress, promotes excessive sphingolipid synthesis, and disturbs energy metabolism by catabolizing NAD⁺ degradation. The antagonistic pleiotropy of AhR signaling is based on the complex and diverse connections with major signaling pathways in a context-dependent manner. The major regulatory steps include, (i) a specific ligand-dependent activation, (ii) modulation of both genetic and non-genetic responses, (iii) a competition and crosstalk with several transcription factors, such as ARNT, HIF-1α, E2F1, and NF-κB, and (iv) the epigenetic regulation of target genes with binding partners. Thus, not only mTOR signaling but also the AhR factor demonstrates antagonistic pleiotropy in the regulation of the aging process.

Single-cell RNA sequencing profiling of mouse endothelial cells in response to pulmonary arterial hypertension

AIMS

Endothelial cell (EC) dysfunction drives the initiation and pathogenesis of pulmonary arterial hypertension (PAH). We aimed to characterize EC dynamics in PAH at single-cell resolution.

METHODS AND RESULTS

We carried out single-cell RNA sequencing (scRNA-seq) of lung ECs isolated from an EC lineage-tracing mouse model in Control and SU5416/hypoxia-induced PAH conditions. EC populations corresponding to distinct lung vessel types, including two discrete capillary populations, were identified in both Control and PAH mice. Differential gene expression analysis revealed global PAH-induced EC changes that were confirmed by bulk RNA-seq. This included upregulation of the major histocompatibility complex class II pathway, supporting a role for ECs in the inflammatory response in PAH. We also identified a PAH response specific to the second capillary EC population including upregulation of genes involved in cell death, cell motility, and angiogenesis. Interestingly, four genes with genetic variants associated with PAH were dysregulated in mouse ECs in PAH. To compare relevance across PAH models and species, we performed a detailed analysis of EC heterogeneity and response to PAH in rats and humans through whole-lung PAH scRNA-seq datasets, revealing that 51% of up-regulated mouse genes were also up-regulated in rat or human PAH. We identified promising new candidates to target endothelial dysfunction including CD74, the knockdown of which regulates EC proliferation and barrier integrity in vitro. Finally, with an in silico cell ordering approach, we identified zonation-dependent changes across the arteriovenous axis in mouse PAH and showed upregulation of the Serine/threonine-protein kinase Sgk1 at the junction between the macro- and microvasculature.

CONCLUSION

This study uncovers PAH-induced EC transcriptomic changes at a high resolution, revealing novel targets for potential therapeutic candidate development.

Microbial metabolite restricts 5-fluorouracil-resistant colonic tumor progression by sensitizing drug transporters via regulation of FOXO3-FOXM1 axis

The survival rate of colorectal cancer patients is adversely affected by the selection of tumors resistant to conventional anti-cancer drugs such as 5-fluorouracil (5FU). Although there is mounting evidence that commensal gut microbiota is essential for effective colon cancer treatment, the detailed molecular mechanisms and the role of gut microbial metabolites remain elusive. The goal of this study is to decipher the impact and mechanisms of gut microbial metabolite, urolithin A (UroA) and its structural analogue, UAS03 on reversal of 5FU-resistant (5FUR) colon cancers. Methods: We have utilized the SW480 and HCT-116 parental (5FU-sensitive) and 5FUR colon cancer cells to examine the chemosensitization effects of UroA or UAS03 by using both in vitro and in vivo models. The effects of mono (UroA/UAS03/5FU) and combinatorial therapy (UroA/UAS03 + 5FU) on cell proliferation, apoptosis, cell migration and invasion, regulation of epithelial mesenchymal transition (EMT) mediators, expression and activities of drug transporters, and their regulatory transcription factors were examined using molecular, cellular, immunological and flowcytometric methods. Further, the anti-tumor effects of mono/combination therapy (UroA or UAS03 or 5FU or UroA/UAS03 + 5FU) were examined using pre-clinical models of 5FUR-tumor xenografts in NRGS mice and azoxymethane (AOM)-dextran sodium sulfate (DSS)-induced colon tumors. Results: Our data showed that UroA or UAS03 in combination with 5FU significantly inhibited cell viability, proliferation, invasiveness as well as induced apoptosis of the 5FUR colon cancer cells compared to mono treatments. Mechanistically, UroA or UAS03 chemosensitized the 5FUR cancer cells by downregulating the expression and activities of drug transporters (MDR1, BCRP, MRP2 and MRP7) leading to a decrease in the efflux of 5FU. Further, our data suggested the UroA or UAS03 chemosensitized 5FUR cancer cells to 5FU treatment through regulating FOXO3-FOXM1 axis. Oral treatment with UroA or UAS03 in combination with low dose i.p. 5FU significantly reduced the growth of 5FUR-tumor xenografts in NRGS mice. Further, combination therapy significantly abrogated colonic tumors in AOM-DSS-induced colon tumors in mice. Conclusions: In summary, gut microbial metabolite UroA and its structural analogue UAS03 chemosensitized the 5FUR colon cancers for effective 5FU chemotherapy. This study provided the novel characteristics of gut microbial metabolites to have significant translational implications in drug-resistant cancer therapeutics.

Using transcriptomics to predict and visualize disease status in bighorn sheep (Ovis canadensis)

Increasing risk of pathogen spillover coupled with overall declines in wildlife population abundance in the Anthropocene make infectious disease a relevant concern for species conservation worldwide. While emerging molecular tools could improve our diagnostic capabilities and give insight into mechanisms underlying wildlife disease risk, they have rarely been applied in practice. Here, employing a previously reported gene transcription panel of common immune markers to track physiological changes, we present a detailed analysis over the course of both acute and chronic infection in one wildlife species where disease plays a critical role in conservation, bighorn sheep (Ovis canadensis). Differential gene transcription patterns distinguished between infection statuses over the course of acute infection and differential correlation (DC) analyses identified clear changes in gene co-transcription patterns over the early stages of infection, with transcription of four genes-TGFb, AHR, IL1b and MX1-continuing to increase even as transcription of other immune-associated genes waned. In a separate analysis, we considered the capacity of the same gene transcription panel to aid in differentiating between chronically infected animals and animals in other disease states outside of acute disease events (an immediate priority for wildlife management in this system). We found that this transcription panel was capable of accurately identifying chronically infected animals in the test dataset, though additional data will be required to determine how far this ability extends. Taken together, our results showcase the successful proof of concept and breadth of potential utilities that gene transcription might provide to wildlife disease management, from direct insight into mechanisms associated with differential disease response to improved diagnostic capacity in the field.

Lactobacillus casei HY2782 and Pueraria lobata Root Extract Complex Ameliorates Particulate Matter-Induced Airway Inflammation in Mice by Inhibiting Th2 and Th17 Immune Responses

This study aimed to investigate the effects of Lactobacillus casei HY2782 and Pueraria lobata root extract complex (HY2782 complex) in mitigating airway inflammation resulting from exposure to particulate matter ≤2.5 μm in diameter (PM2.5) in an animal model. Chronic inflammatory airway disease is associated with Th2-related cytokines interleukin (IL)-4, IL-5, and IL-13 and Th17-related cytokine IL-17A, which are the major contributors to allergy and asthma. Results indicated that PM2.5 elevates allergen-related airway inflammation and respiratory hyperresponsiveness in C57BL/6 mice. The HY2782 complex significantly reduced Th2/Th17-derived cytokines IL-4, IL5, IL-13, and IL-17A; immunoglobulin E; and leukotriene C₄ in bronchoalveolar lavage fluid (BALF) and serum. Furthermore, the HY2782 complex was associated with the modulation of oxidative stress-related genes. Administration of the HY2782 complex resulted in a markedly reduced number of neutrophils and eosinophil infiltration in BALF. Histopathological observation of lung tissue also showed reduced inflammatory cell infiltration into airways and surrounding tissue. The HY2782 complex may be a promising candidate for the preventive therapy of allergic diseases and airway inflammation caused by PM2.5 inhalation.

Prostate cancer addiction to oxidative stress defines sensitivity to anti-tumor neutrophils

Bone metastatic prostate cancer (BM-PCa) remains one of the most difficult cancers to treat due to the complex interactions of cancer and stromal cells. We previously showed that bone marrow neutrophils elicit an anti-tumor immune response against BM-PCa. Further, we demonstrated that BM-PCa induces neutrophil oxidative burst, which has previously been identified to promote primary tumor growth of other cancers, and a goal of this study was to define the importance of neutrophil oxidative burst in BM-PCa. To do this, we first examined the impact of depletion of reactive oxygen species (ROS), via systemic deletion of the main source of ROS in phagocytes, NADPH oxidase (Nox)2, which we found to suppress prostate tumor growth in bone. Further, using pharmacologic ROS inhibitors and Nox2-null neutrophils, we found that ROS depletion specifically suppresses growth of androgen-insensitive prostate cancer cells. Upon closer examination using bulk RNA sequencing analysis, we identified that metastatic prostate cancer induces neutrophil transcriptomic changes that activates pathways associated with response to oxidative stress. In tandem, prostate cancer cells resist neutrophil anti-tumor response via extracellular (i.e., regulation of neutrophils) and intracellular alterations of glutathione synthesis, the most potent cellular antioxidant. These findings demonstrate that BM-PCa thrive under oxidative stress conditions and such that regulation of ROS and glutathione programming could be leveraged for targeting of BM-PCa progression.

The Aryl Hydrocarbon Receptor Ligand FICZ Improves Left Ventricular Remodeling and Cardiac Function at the Onset of Pressure Overload-Induced Heart Failure in Mice

Adverse ventricular remodeling is the heart's response to damaging stimuli and is linked to heart failure and poor prognosis. Formyl-indolo [3,2-b] carbazole (FICZ) is an endogenous ligand for the aryl hydrocarbon receptor (AhR), through which it exerts pleiotropic effects including protection against inflammation, fibrosis, and oxidative stress. We evaluated the effect of AhR activation by FICZ on the adverse ventricular remodeling that occurs in the early phase of pressure overload in the murine heart induced by transverse aortic constriction (TAC). Cardiac structure and function were evaluated by cardiac magnetic resonance imaging (CMRI) before and 3 days after Sham or TAC surgery in mice treated with FICZ or with vehicle, and cardiac tissue was used for biochemical studies. CMRI analysis revealed that FICZ improved cardiac function and attenuated cardiac hypertrophy. These beneficial effects involved the inhibition of the hypertrophic calcineurin/NFAT pathway, transcriptional reduction in pro-fibrotic genes, and antioxidant effects mediated by the NRF2/NQO1 pathway. Overall, our findings provide new insight into the role of cardiac AhR signaling in the injured heart.

Triclosan (TCS) affects the level of DNA methylation in the human oral squamous cell carcinoma (SCC-15) cell line in a nontoxic concentration

The oral cancer is presumably caused by genetic factors and exposure to substances derived from cosmetics and disinfectants. Triclosan (TCS) is widely spread in many consumer products and oral care products. Since TCS can affect DNA methylation, which is one of the key mechanisms of gene expression that may lead to cancerogenesis, it is necessary to study this mechanism in oral cell carcinoma. The aim of the present study was to evaluate the impact of TCS on metabolic parameters, oxidative stress, gene expression, and DNA methylation and hydroxymethylation in the SCC-15 cell line. The experiments have shown TCS toxicity to SCC-15 cells only in the highest concentrations of 50 and 100 µM. TCS in a wide range of concentrations increases ROS production and caspase-3 activity. Our experiments have shown that TCS in the nontoxic concentrations of 10 µM exerts an impact on SOD2 mRNA expression and SOD activity in the SCC-15 cell line. Finally, our experiments have demonstrated that 6-h treatment with TCS decreases the mRNA expression of DNMT3A and DNMT3B. After 72-h exposure to TCS, an increased level of 5-methylcytosine and 5-hydroxymethylcytosine was observed in the SCC-15 cell line, but it was abolished by the NAC treatment. However, it is very likely that these results can be an effect of TET enzyme activity, especially in the case of the decrease in 5mC and the increase in 5hmC after the 48-h exposure to TCS, which was accompanied with a decrease in the mRNA expression of DNMT3A and DNMT3B.

α-Tocopherol Prevents Sperm Apoptosis and Necrosis in Rats Exposed to 2,3,7,8-Tetrachlorodibenzo-p-dioxin

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a persistent organic pollutant that induces overproduction of reactive oxygen species (ROS). Studies on avoiding the adverse effects of dioxin pollution exposure are needed in all aspects, including reproductive health. This study aimed to determine the effect of α-tocopherol on superoxide dismutase (SOD) and malondialdehyde (MDA) levels, live spermatozoa, apoptosis, and necrosis in male rats exposed to dioxin as a model. Thirty healthy 12-week-old male rats were randomly divided into five groups. Rats in the control group were given corn oil twice daily at 4-hour intervals. The remaining rats were given TCDD 700 mg/kg BW daily, followed by administration of corn oil and α-tocopherol at doses of 77, 140, and 259 mg/kg BW/d for T0, T1, T2, and T3 groups, respectively. The treatments were conducted for 45 days; all rats were euthanized to collect blood and testicular samples on day 46. The results showed that exposure of TCDD resulted in a decrease in SOD activity and live spermatozoa and increased MDA level and death, apoptosis, and necrosis of spermatozoa (T0) compared to the control (C) group (p < 0.05). The administration of α-tocopherol, starting from the doses of 77 (T1), 149 (T2), and 259 mg (T3) per kg BW, was sequentially followed by returning MDA levels, recovering SOD activities, and restoration in the percentage of living, dead, apoptotic, and necrotic spermatozoa, similar (p > 0.05) to those of the control group. It could be concluded that the administration of α-tocopherol resolves the harmful effects of TCDD on the viability of spermatozoa in rats as a model.

Genetic variants affecting chemical mediated skin immunotoxicity

The skin is an immune-competent organ and this function may be impaired by exposure to chemicals, which may ultimately result in immune-mediated dermal disorders. Interindividual variability to chemical-induced skin immune reactions is associated with intrinsic individual characteristics and their genomes. In the last 30-40 years, several genes influencing susceptibility to skin immune reactions were identified. The aim of this review is to provide information regarding common genetic variations affecting skin immunotoxicity. The polymorphisms selected for this review are related to xenobiotic-metabolizing enzymes (CYPA1 and CYPB1 genes), antioxidant defense (GSTM1, GSTT1, and GSTP1 genes), aryl hydrocarbon receptor signaling pathway (AHR and ARNT genes), skin barrier function transepidermal water loss (FLG, CASP14, and SPINK5 genes), inflammation (TNF, IL10, IL6, IL18, IL31, and TSLP genes), major histocompatibility complex (MHC) and neuroendocrine system peptides (CALCA, TRPV1, ACE genes). These genes present variants associated with skin immune responses and diseases, as well as variants associated with protecting skin immune homeostasis following chemical exposure. The molecular and association studies focusing on these genetic variants may elucidate their functional consequences and contribution in the susceptibility to skin immunotoxicity. Providing information on how genetic variations affect the skin immune system may reduce uncertainties in estimating chemical hazards/risks for human health in the future.

α-Tocopherol restores semen quality in rats exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin

Background and Aim:

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent organic pollutant toxic to the human reproductive system. This study aimed to evaluate the effect of α-Tocopherol administration on the male fertility parameters of a rat model exposed to TCDD.

Materials and Methods:

Fifty healthy 12-week-old male rats were randomly divided into five groups. Rats in the control group were given corn oil twice daily in 4 h intervals. In the treatment groups, all rats were given TCDD at a dose of 700 ng/kg of body weight (BW)/day for 45 days. Four hours after receiving the TCDD, T0 rats were given corn oil, and T1, T2, and T3 rats were given α-Tocopherol at doses of 77, 140, and 259 mg/kg BW/day, respectively, for 45 days. On day 46, experimental animals were sacrificed to collect blood and testicular samples.

Results:

TCDD exposure decreased superoxide dismutase activity, plasma membrane integrity, Leydig cell count, sperm cell count, sperm viability and motility, and increased malondialdehyde levels, serum testosterone levels, and sperm morphological abnormalities. The administration of α-Tocopherol mitigated the effects of TCDD exposure, and the 140 and 259 mg/kg BW/day treatments returned those male fertility parameters to normal levels.

Conclusion:

The administration of 140 mg/kg BW/day α-Tocopherol restored male semen quality in rats exposed to TCDD. We found dynamics serum testosterone levels in rats exposed to TCDD that need to be further studied.

AHR gene expression and the polymorphism rs2066853 are associated with clinicopathological parameters in colorectal carcinoma

The relationship between red and processed meat and its risk towards colorectal carcinoma (CRC) is not fully explored in literature. Polycyclic aromatic hydrocarbons (PAHs) are pro-carcinogenic molecules that are ingested with meat cooked at high temperatures. The metabolic conversion of PAHs to carcinogenic diol epoxides is in part mediated by the aryl hydrocarbon receptor (AhR)-dependent induction of CYP1A1. This study aims to examine and expression profiles and polymorphisms of the AHR (aryl hydrocarbon receptor) gene which is involved in the metabolic conversion of PAHs in patients with CRC. Genetic analysis was done in matched cancer and non-neoplastic tissues from 79 patients diagnosed with CRCs. Low AHR mRNA expression was associated mucinous colorectal adenocarcinoma. Exon 10 of AHR showed that 27% of patients had the rs2066853 single nucleotide polymorphism resulting in an arginine to lysine change at codon 554. This variant was significantly associated with a lower likelihood of perineural invasion, presence of synchronous cancer, and multiple colorectal polyps. Furthermore, rs2066853 individuals were significantly more likely to be of more advanced age and have a more favourable tumour grade and pathological stage. These results imply the pathogenic roles of AHR in PAH-associated colorectal carcinogenesis.

Aryl Hydrocarbon Receptor Inhibition Restores Indoxyl Sulfate-Mediated Endothelial Dysfunction in Rat Aortic Rings

The uremic toxin indoxyl sulfate (IS), elevated in chronic kidney disease (CKD), is known to contribute towards progressive cardiovascular disease. IS activates the aryl hydrocarbon receptor (AhR) mediating oxidative stress and endothelial dysfunction via activation of the CYP1A1 pathway. The present study examines AhR inhibition with the antagonist, CH223191, on IS-mediated impairment of vascular endothelial function and disruption of redox balance. The acute effects of IS on endothelium-dependent relaxation were assessed in aortic rings from Sprague Dawley rats exposed to the following conditions: (1) control; (2) IS (300 μM); (3) IS + CH223191 (1 μM); (4) IS + CH223191 (10 μM). Thereafter, tissues were assessed for changes in expression of redox markers. IS reduced the maximum level of endothelium-dependent relaxation (Rmax) by 42% (p < 0.001) compared to control, this was restored in the presence of increasing concentrations of CH223191 (p < 0.05). Rings exposed to IS increased expression of CYP1A1, nitro-tyrosine, NADPH oxidase 4 (NOX4), superoxide, and reduced eNOS expression (p < 0.05). CH223191 (10 μM) restored expression of these markers back to control levels (p < 0.05). These findings demonstrate the adverse impact of IS-mediated AhR activation on the vascular endothelium, where oxidative stress may play a critical role in inducing endothelial dysfunction in the vasculature of the heart and kidneys. AhR inhibition could provide an exciting novel therapy for CVD in the CKD setting.

Bilirubin ameliorates murine atherosclerosis through inhibiting cholesterol synthesis and reshaping the immune system

Atherosclerosis is a chronic inflammatory disease caused mainly by lipid accumulation and excessive inflammatory immune response. Although the lipid-lowering and cardioprotective properties of bilirubin, as well as the negative relationship between bilirubin and atherosclerosis, were well documented, it is not yet clear whether bilirubin can attenuate atherosclerosis in vivo. In this study, we investigated the role of bilirubin in improving atherosclerosis. We found that mildly elevated bilirubin significantly reduced the risk factors of atherosclerosis, such as plasma glucose, total cholesterol, and low-density lipoprotein cholesterol, and the formation of atherosclerotic plaques, liver total cholesterol, and cholesterol ester concentration in apolipoprotein E-deficient (ApoE^-/-) mice fed a western-type (high fat) diet. It was further found that bilirubin could promote the degradation of 3-Hydroxy-3-Methylglutaryl-CoA Reductase (HMGCR), a rate-limiting enzyme for endogenous cholesterol synthesis. Using mass cytometry-based high dimensional single cell analysis, we observed a decrease of natural killer cells and an increase of dendritic cells and myeloid-derived suppressor cells, which all are closely associated with atherosclerosis risk factors and contribute to the improvement of atherosclerosis, in ApoE^-/- mice treated with bilirubin. By in-depth analysis, modulation of multiple spleen or peripheral blood T cell clusters exhibiting either positive or negative correlations with total cholesterol or low-density lipoprotein cholesterol was detected after bilirubin treatment. In this study, we demonstrate that bilirubin serves as a negative regulator of atherosclerosis and reduces atherosclerosis by inhibiting cholesterol synthesis and modulating the immune system.

The Sulfotransferase SULT1C2 Is Epigenetically Activated and Transcriptionally Induced by Tobacco Exposure and Is Associated with Patient Outcome in Lung Adenocarcinoma

Lung cancer is the leading cause of cancer-related death. Tobacco exposure is associated with 80-90% of lung cancer cases. The SULT1C2 sulfotransferase modifies xenobiotic compounds to enhance secretion but can also render these compounds carcinogenic. To determine if SULT1C2 contributes to tobacco-related carcinogenesis in the lung, we analyzed the expression and epigenetic state of SULT1C2 in human lung adenocarcinoma (LUAD) samples and in LUAD cell lines exposed to cigarette smoke condensate (CSC). SULT1C2 expression was significantly positively correlated to overall LUAD patient survival in smokers, was elevated in LUAD tumors compared to adjacent non-tumor lung, and was significantly correlated with levels of patient exposure to tobacco smoke. SULT1C2 promoter DNA methylation was inversely correlated with expression in LUAD, and hypomethylation of the SULT1C2 promoter was observed in Asian patients, as compared to Caucasians. In vitro analysis of LUAD cell lines indicates that CSC stimulates expression of SULT1C2 in a dose-dependent and cell-line-specific manner. In vitro methylation of the SULT1C2 promoter significantly decreased transcriptional activity of a reporter plasmid, and SULT1C2 expression was activated by the DNA demethylating agent 5-Aza-2'-deoxycytidine in a cell line in which the SULT1C2 promoter was hypermethylated. An aryl hydrocarbon receptor (AHR) binding site was detected spanning critical methylation sites upstream of SULT1C2. CSC exposure significantly increased AHR binding to this predicted binding site in the SULT1C2 promoter in multiple lung cell lines. Our data suggest that CSC exposure leads to activation of the AHR transcription factor, increased binding to the SULT1C2 promoter, and upregulation of SULT1C2 expression and that this process is inhibited by DNA methylation at the SULT1C2 locus. Additionally, our results suggest that the level of SULT1C2 promoter methylation and gene expression in normal lung varies depending on the race of the patient, which could in part reflect the molecular mechanisms of racial disparities seen in lung cellular responses to cigarette smoke exposure.

The deleterious effects induced by an acute exposure of human skin to common air pollutants are prevented by extracts of Deschampsia antarctica

The homeostatic and regenerative potential of the skin is critically impaired by an increasing accumulation of air pollutants in human ecosystems. These toxic compounds are frequently implicated in pathological processes such as premature cutaneous ageing, altered pigmentation and cancer. In this scenario, innovative strategies are required to tackle the effects of severe air pollution on skin function. Here we have used a Human Skin Organotypic Culture (HSOC) model to characterize the deleterious effects of an acute topic exposure of human skin to moderately high concentrations of common ambient pollutants, including As, Cd, Cr, dioxins and tobacco smoke. All these toxic compunds inflict severe damage in the tissue, activating the AHR-mediated response to xenobiotics. We have further evaluated the potential of an aqueous leaf extract of the polyextremophile plant Deschampsia antarctica (Edafence) to protect human skin against the acute exposure to toxic pollutants. Our results indicate that pre-treatment of HSOC samples with this aqueous extract conuterbalances the deleterious effects of the exposure to toxic comunds and triggers the activation of key genes invoved in the redox system and in the pro-inflammatory/wound healing response in the skin, suggesting that this natural compound might be effectively used in vivo to protect human skin routinely in different daily conditions.

Detection of double-stranded DNA breaks and apoptosis induced by bleomycin in mouse intestine

The gastrointestinal tract is exposed to a myriad of mutagens, making the DNA damage response (DDR) essential to maintain intestinal homeostasis. In vivo models to study DDRs are necessary to understand the mechanisms of disease development caused by genetic disorders such as colorectal cancer. A double-stranded break (DSB) in DNA is the most toxic type of DNA damage; it can be induced by either X-rays or chemicals, including anticancer agents. If DSBs in DNA cannot be repaired, cells can die by apoptosis to be removed from tissues. Here, we show that the DDRs observed as the phosphorylation of H2AX (γH2AX) and caspase-3-dependent apoptosis-induction are under critical control in the intestine of C57BL mice that were injected intraperitoneally with bleomycin, a natural glycopeptide used clinically as an antitumor agent. We found a significant increase in γH2AX expression 2-6 hr post-treatment in mouse ileum, cecum, and colon tissues by Western blotting and immunostaining. Apoptotic cells were observed after 6-24 hr by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and immunofluorescence of active caspase-3. We observed that γH2AX expression and apoptotic cells were distributed in the lower part of the crypt. The experimental protocol described here is a simple procedure that can be used generally as an in vivo intestinal toxicity assay. Our experimental approach provides a useful method for examining the effects of various bioactive compounds on the DDR, which is essential for understanding intestinal homeostasis.

Validation of in vitro models for smoke exposure of primary human bronchial epithelial cells

RATIONALE

The bronchial epithelium is constantly challenged by inhalative insults including cigarette smoke (CS), a key risk factor for lung disease. In vitro exposure of bronchial epithelial cells using CS extract (CSE) is a widespread alternative to whole CS (wCS) exposure. However, CSE exposure protocols vary considerably between studies, precluding direct comparison of applied doses. Moreover, they are rarely validated in terms of physiological response in vivo and the relevance of the findings is often unclear.

METHODS

We tested six different exposure settings in primary human bronchial epithelial cells (phBECs), including five CSE protocols in comparison with wCS exposure. We quantified cell-delivered dose and directly compared all exposures using expression analysis of 10 well-established smoke-induced genes in bronchial epithelial cells. CSE exposure of phBECs was varied in terms of differentiation state, exposure route, duration of exposure, and dose. Gene expression was assessed by quantitative Real-Time PCR (qPCR) and Western Blot analysis. Cell type-specific expression of smoke-induced genes was analyzed by immunofluorescent analysis.

RESULTS

Three surprisingly dissimilar exposure types, namely chronic CSE treatment of differentiating phBECs, acute CSE treatment of submerged basal phBECs, and wCS exposure of differentiated phBECs performed best, resulting in significant upregulation of seven (chronic CSE) and six (acute wCS, acute submerged CSE exposure) out of 10 genes. Acute apical or basolateral exposure of differentiated phBECs with CSE was much less effective despite similar doses used.

CONCLUSIONS

Our findings provide guidance for the design of human in vitro CS exposure models in experimental and translational lung research.