Toxicity of polycyclic aromatic hydrocarbons involves NOX2 activation

New imidazole-2-thiones linked to acenaphythylenone as dual DNA intercalators and topoisomerase II inhibitors: structural optimization, docking, and apoptosis studies

In this article, a new series of 2-((3,5-disubstituted-2-thioxo-imidazol-1-yl)imino)acenaphthylen-1(2H)-ones were synthesized. Imidazole-2-thione with acenaphthylen-one gave a hybrid scaffold that integrated key structural elements essential for DNA damage via direct DNA intercalation and inhibition of the topoisomerase II enzyme. All the synthesized compounds were screened to detect their DNA damage using a terbium fluorescent probe. Results demonstrated that 4-phenyl-imidazoles 5b and 5e in addition to 4-(4-chlorophenyl)imidazoles 5h and 5j would induce detectable potent damage in ctDNA. The four most potent compounds as DNA intercalators were further evaluated for their antiproliferative activity against HepG2, MCF-7 and HCT-116 utilizing the MTT assay. The highest anticancer activity was recorded with compounds 5b and 5h against the breast cancer cell line MCF-7 which were 1.5- and 3- folds more active than doxorubicin, respectively. Therefore, imidazole-2-thione tethered acenaphthylenone derivatives can be considered as promising scaffold for the development of effective dual DNA intercalators and topoisomerase II inhibitors.

Sub-acute exposure of male guppies (Poecilia reticulata) to environmentally relevant concentrations of PFOA and GenX induces significant changes in the testis transcriptome and reproductive traits

Poly- and perfluoroalkyl substances (PFAS) are frequently detected in the environment and are linked to adverse reproductive health outcomes in humans. Although legacy PFAS have been phased out due to their toxicity, alternative PFAS are increasingly used despite the fact that information on their toxic effects on reproductive traits is particularly scarce. Here, we exposed male guppies (Poecilia reticulata) for a short period (21 days) to an environmentally realistic concentration (1 ppb) of PFOA, a legacy PFAS, and its replacement compound, GenX, to assess their impact on reproductive traits and gene expression. Exposure to PFAS did not impair survival but instead caused sublethal effects. Overall, PFAS exposure caused changes in male sexual behaviour and had detrimental effects on sperm motility. Sublethal variations were also seen at the transcriptional level, with the modulation of genes involved in immune regulation, spermatogenesis, and oxidative stress. We also observed bioaccumulation of PFAS, which was higher for PFOA than for GenX. Our results offer a comprehensive comparison of these two PFAS and shed light on the toxicity of a newly emerging alternative to legacy PFAS. It is therefore evident that even at low concentrations and with short exposure, PFAS can have subtle yet significant effects on behaviour, fertility, and immunity. These findings underscore the potential ramifications of pollution under natural conditions and their impact on fish populations.

A new on-line SPE LC-HRMS method for the analysis of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) in PM2.5 and its application for screening atmospheric particulates from Dublin and Enniscorthy, Ireland

A sensitive analytical method has been developed and validated for the determination of 16 polyfluorinated alkyl substances (PFAS) in fine airborne particulate matter (PM_2.5) using on-line solid phase extraction (SPE) coupled with liquid chromatography (LC) - negative electrospray ionisation high resolution mass spectrometry (-) ESI-HRMS. On-line SPE allows simultaneous sample clean-up from interfering matrices and lower limits of detection (LODs) by injecting a large volume of sample into the LC system without compromising chromatographic efficiency and resolution. The method provides LODs in the range 0.08-0.5 pg/mL of sample extract allowing detection of selected PFAS in aerosol particles at low fg/m³ level and showed good tolerance to the considered PM matrix. The validated method was applied for analysis of PFAS in ambient PM_2.5 samples collected at two urban locations in Ireland, i.e., Enniscorthy and Dublin. Several PFAS were observed above the detection limit, including perfluorobutyrate (PFBA), perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorobutanesulfonic acid (L-PFBS) and perfluorononanoic acid (PFNA), as well as fluorotelomer sulfonates: 4:2 FTS, 6:2 FTS and 8:2 FTS. The results indicate that some toxic PFAS, such as PFOS and PFOA, are still detected in the environment despite being phased out from production and subject to restricted use in the EU and USA for more than two decades. Observation of fluorotelomer sulfonates (4:2 FTS, 6:2 FTS and 8:2 FTS, which are used as alternatives for legacy PFOA and PFOS) in ambient PM_2.5 samples raises a concern about their persistence in the atmosphere and impact on human health considering emerging evidence that they could have similar health endpoints as PFOA and PFOS. To our knowledge, this is the first study to identify PFAS in ambient PM_2.5 at urban locations in Ireland and also the first study to detect 4:2 and 8:2 fluorotelomer sulfonates in atmospheric aerosol particles.

In Silico Insights on the Pro-Inflammatory Potential of Polycyclic Aromatic Hydrocarbons and the Prospective Anti-Inflammatory Capacity of Andrographis paniculata Phytocompounds

Inflammation linked to various diseases is the biological response to certain stimuli. The pro-inflammatory potential of Polycyclic Aromatic Hydrocarbons (PAHs) as potential inducers of inflammation bound to the Toll-like Receptor 4 (TLR4) and the anti-inflammatory capacity of A. paniculata (AP) phytocompounds as prospective inhibitors of the Nuclear Factor Kappa B (NF-κB) p50 transcription factor are investigated via in silico techniques. The molecular docking of the PAHs and AP phytocompounds is performed in AutoDock Vina by calculating their binding energies. The molecular dynamics simulations (MDS) of the apo and ligand-bound complex of the top binding ligands were performed in CABS-flex. The agonists, which included the PAHs indeno(1,2,3-cd)pyrene (IP), and dibenz(a,h)anthracene (DahA), had the highest binding energies of −10 kcal/mol and −9.2 kcal/mol, respectively. The most stable antagonists in the binding site with binding energies to the NF-κB p50 were the AP phytocompounds with −5.6 kcal/mol for ergosterol peroxide and −5.3 kcal/mol for 14-deoxy-14,15-dehydroandrographolide. The MDS of the apo human TLR4 and PAH-bound TLR4, and the apo p50 and the AP phytocompound-bound NF-κB p50 showed minimal fluctuations. These results reveal that IP and DahA are significant inducers of inflammation, whereas ergosterol peroxide and 14-deoxy-14,15-dehydroandrographolide are inhibitors of the NF-κB pathway. Furthermore, the study theorizes that any inflammatory activity induced by PAH can be potentially inhibited by A. paniculata phytocompounds.

Aryl Hydrocarbon Receptor in Oxidative Stress as a Double Agent and Its Biological and Therapeutic Significance

The aryl hydrocarbon receptor (AhR) has long been implicated in the induction of a battery of genes involved in the metabolism of xenobiotics and endogenous compounds. AhR is a ligand-activated transcription factor necessary for the launch of transcriptional responses important in health and disease. In past decades, evidence has accumulated that AhR is associated with the cellular response to oxidative stress, and this property of AhR must be taken into account during investigations into a mechanism of action of xenobiotics that is able to activate AhR or that is susceptible to metabolic activation by enzymes encoded by the genes that are under the control of AhR. In this review, we examine various mechanisms by which AhR takes part in the oxidative-stress response, including antioxidant and prooxidant enzymes and cytochrome P450. We also show that AhR, as a participant in the redox balance and as a modulator of redox signals, is being increasingly studied as a target for a new class of therapeutic compounds and as an explanation for the pathogenesis of some disorders.

Natural and Synthetic Estrogens in Chronic Inflammation and Breast Cancer

The oncogenic role of estrogen receptor (ER) signaling in breast cancer has long been established. Interaction of estrogen with estrogen receptor (ER) in the nucleus activates genomic pathways of estrogen signaling. In contrast, estrogen interaction with the cell membrane-bound G-protein-coupled estrogen receptor (GPER) activates the rapid receptor-mediated signaling transduction cascades. Aberrant estrogen signaling enhances mammary epithelial cell proliferation, survival, and angiogenesis, hence is an important step towards breast cancer initiation and progression. Meanwhile, a growing number of studies also provide evidence for estrogen's pro- or anti-inflammatory roles. As other articles in this issue cover classic ER and GPER signaling mediated by estrogen, this review will discuss the crucial mechanisms by which estrogen signaling influences chronic inflammation and how that is involved in breast cancer. Xenoestrogens acquired from plant diet or exposure to industrial products constantly interact with and alter innate estrogen signaling at various levels. As such, they can modulate chronic inflammation and breast cancer development. Natural xenoestrogens generally have anti-inflammatory properties, which is consistent with their chemoprotective role in breast cancer. In contrast, synthetic xenoestrogens are proinflammatory and carcinogenic compounds that can increase the risk of breast cancer. This article also highlights important xenoestrogens with a particular focus on their role in inflammation and breast cancer. Improved understanding of the complex relationship between estrogens, inflammation, and breast cancer will guide clinical research on agents that could advance breast cancer prevention and therapy.

Cytotoxicity and inflammatory effects in human bronchial epithelial cells induced by polycyclic aromatic hydrocarbons mixture

Polycyclic aromatic hydrocarbons (PAHs) are the most common contaminants in the air pollutants. Inhalation exposure to PAHs could increase the risk of respiratory disease, cardiovascular disease and even cancer. However, the biotoxicity of multi-component PAHs from atmospheric pollutants has been poorly studies. The main topic of this study was to investigate the PAHs mixture, which derived from atmospheric pollutants, induced toxic effects and inflammatory effects on human bronchial epithelial cells in vitro. The results showed that PAHs mixture could decrease the cell viability, increase the apoptosis rate, and induce cell cycle arrest at S-phase. Furthermore, the expression of inflammatory factors IL-1β and IL-6 were increased and NF-κB signaling pathway was activated in PAHs mixture-treated cells. The findings of this study indicate that PAHs mixture-induced cytotoxicity and inflammation may be related to intracellular ROS generation and to the activated NF-κB signaling pathway.

Occurrence of polycyclic aromatic hydrocarbons in fried and grilled fish from Shandong China and health risk assessment

Diet is the main way for the human body to ingest polycyclic aromatic hydrocarbons (PAHs). In this study, the occurrence, dietary exposure, and health risks of 15 PAHs in 31 fried and grilled fish samples were investigated, which were collected from the Shandong Province of China. The results showed that benzo[a]pyrene (BaP) of 5 samples exceeded the European Union (EU) limit value. Naphthalene (NaP) and fluorene (Fle) were present in all samples, and the average concentration of ∑15PAHs was 91.1 μg/kg, with light PAHs dominated. The average contamination level of ∑15PAHs in fried and grilled fish was distributed differently, and there seemed to be more PAH contamination in the grilled samples. The results of the margin of exposure (MOE) suggested that PAH ingestion through fried and grilled fish did not imply significant toxicological concern for consumers in Shandong. The incremental lifetime cancer risk (ILCR) values for the consumption of fried and grilled fish were higher than 1 × 10-6, indicating a potential health risk in the adult population. The study provides baseline health information on PAH intake by residents due to dietary exposure to fried and grilled fish food products, suggesting that health risk monitoring of PAHs in such foods should be continually performed.

Estimated 24-hour urinary sodium excretion as a risk factor for oxidative stress in Zambian adults: A cross-sectional study

Introduction

Persistent oxidative stress predisposes to various non-communicable diseases (NCDs), whose occurrence is increasing in sub-Saharan Africa. The aim of this study was to evaluate the link between markers of oxidative stress and some risk factors for NCDs in a Zambian cohort.

Methods

We assessed oxidative stress by measuring 8-isoprostane (lipid oxidative stress) and 8-hydroxydeoxyguanosine (DNA oxidative stress). In addition, we measured mycotoxins (aflatoxin M1 and ochratoxin A), salt intake estimated from 24-hour sodium excretion calculated using the Tanaka and Kawaski formulae, and 1-hydroxypyrene (a metabolite of polycyclic aromatic hydrocarbons). Data on lifestyle risk factors were collected using questionnaires.

Results

Included were 244 participants; 128 (52%) were female and the median age was 48 years (IQR 39–58). The median level of 8-isoprostane was 0.13 ng/mg creatinine (IQR 0.08–0.23) while that of 8-hydroxydeoxyguanosine (8-OHdG) was 4 ng/mg creatinine (IQR 2–10). The median 24-hour sodium excretion was 21 g (IQR 16–25 g), with none being less than the 5 g recommended by WHO. Unadjusted urinary levels of 8-isoprostane were moderately correlated with 1-hydroxypyrene (Spearman r = 0.30, p<0.001) and estimated 24-hour urine sodium (Spearman r = 0.38, p<0.001). Urinary levels of 8-OHdG were not correlated with 1-hydroxypyrene, estimated 24-hour urine sodium, aflatoxin M1 or ochratoxin A (all p-values >0.05). Using logistic regression, adjusted and unadjusted 8-isoprostanes levels were associated with 1-hydroxypyrene (p = 0.02 and p = 0.001 respectively) and estimated 24-hour urine sodium method (p = 0.003 and p<0.001 respectively). However, only unadjusted 8-OHdG was associated with 1-hydroxypyrene (p = 0.03) and age (p = 0.007).

Conclusions

Estimated 24-hour urinary sodium is high among Zambians and it is associated with lipid but not DNA oxidative stress. High exposure to polycyclic aromatic hydrocarbons is also associated with oxidative stress.

Contributions of dietary, demographic, disease, lifestyle and other factors in explaining variabilities in concentrations of selected monohydroxylated polycyclic aromatic hydrocarbons in urine: Data for US children, adolescents, and adults

Data from National Health and Nutrition Examination Survey for 2003-2014 for US children aged 6-11 years (N = 2097), adolescents aged 12-19 ears (N = 2642), and adults aged ≥ 20 years (N = 9170) were analyzed to investigate the effects of dietary, demographic, disease, lifestyle, and other factors on concentrations of nine metabolites of polycyclic aromatic hydrocarbons (PAH) in urine. PAHs analyzed were: 1-hydroxynaphthalene, 2-hydroxynaphthalene, 2-hydroxyfluorene, 3-hydroxyfluorene, 9-hydroxyfluorene, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, 3-hydroxyphenanthrene, and 1-hydroxypyrene. Adults with diabetes were found to have higher adjusted levels of 1-hydroxynaphthalene (4139 vs. 3622 ng/L, p < 0.01) than nondiabetics. Adults with albuminuria had higher adjusted levels of 1-hydroxynaphthalene (4140 vs.3621 ng/L, p < 0.01) and 2-hydroxynaphthalene (6039 vs. 5468 ng/L, p < 0.01) than those without albuminuria. Children with albuminuria had lower adjusted levels of 9-hydroxyfluorene (162 vs. 187 ng/L, p = 0.04), 1-hydroxyphenanthrene (92 vs. 108 ng/L, p < 0.01), and 1-hydroxypyrene (118 vs. 138 ng/L, p < 0.01) than those without albuminuria. The ratios of smoker to nonsmoker adjusted levels for adults varied from a low of 1.4 for 2-hydroxyphenanthrene to a high of 5.6 for 3-hydroxyfluorene. Exposure to environmental tobacco smoke at home was associated with higher levels of most OH-PAHs among children, adolescents, and adults. Consumption of red meat not processed at high temperatures was associated with increased levels of 1-hydroxypyrene (β = 0.00040, p = 0.01), 1-, 2-, and 3-hydroxyphenanthrene, 3-, and 9-hydroxyfluorene. Consumption of red meat processed at high temperatures was associated with increased levels of 2-hydroxynaphthalene (β = 0.00046, p = 0.02) among adults. Consumption of fish processed at high temperatures was associated with decreased levels of 1-hydroxynaphtahlene (β = - 0.00088, p < 0.01), 2-, 3-, and 9-hydroxyfluorene, 1-, 2-, and 3-hydroxyphenanthrene. Among adults, alcohol consumption and caffeine may be associated with increased levels of certain OH-PAHs. Oxidative stress and inflammation associated with exposure to PAHs are associated with albuminuria and have the potential to lead to the development of diabetes.

The aryl hydrocarbon receptor as a target of environmental stressors - Implications for pollution mediated stress and inflammatory responses

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor regulating the expression of genes, for instance encoding the monooxygenases cytochrome P450 (CYP) 1A1 and CYP1A2, which are important enzymes in metabolism of xenobiotics. The AHR is activated upon binding of polycyclic aromatic hydrocarbons (PAHs), persistent organic pollutants (POPs), and related ubiquitous environmental chemicals, to mediate their biological and toxic effects. In addition, several endogenous and natural compounds can bind to AHR, thereby modulating a variety of physiological processes. In recent years, ambient particulate matter (PM) associated with traffic related air pollution (TRAP) has been found to contain significant amounts of PAHs. PM containing PAHs are of increasing concern as a class of agonists, which can activate the AHR. Several reports show that PM and AHR-mediated induction of CYP1A1 results in excessive generation of reactive oxygen species (ROS), causing oxidative stress. Furthermore, exposure to PM and PAHs induce inflammatory responses and may lead to chronic inflammatory diseases, including asthma, cardiovascular diseases, and increased cancer risk. In this review, we summarize findings showing the critical role that the AHR plays in mediating effects of environmental pollutants and stressors, which pose a risk of impacting the environment and human health.

•

PAHs present on ambient air pollution particles are ligands of the cellular AHR.

•

AHR-dependent induction of CYP1, AKR, NOX and COX-2 genes can be a source of ROS generation.

•

AHR signaling and NRF2 signaling interact to regulate the expression of antioxidant genes.

•

Air pollution and ROS can affect inflammation, which is partially triggered by AHR and associated immune responses.

•

Skin, lung, and the cardiovascular system are major target sites for air pollution-induced inflammation.