The environmental pollutant, polychlorinated biphenyl 126, alters liver function in a rodent model of alcohol-associated liver disease

BACKGROUND

The prevalence of alcohol-associated liver disease (ALD), a subtype of fatty liver disease (FLD), continues to rise. ALD is a major cause of preventable death. Polychlorinated biphenyl (PCB) 126 is an environmentally relevant, dioxin-like pollutant whose negative metabolic effects have been well documented. In human and animal studies, PCB has been associated with the severity of nonalcoholic fatty liver disease (NAFLD). However, few studies have investigated whether exposures to environmental toxicants can worsen ALD. Thus, the objective of the current study was to develop an alcohol-plus-toxicant model to study how an environmental pollutant, PCB 126, impacts rodent ALD pathology.

METHODS

Briefly, male C57BL/6J mice were exposed to 0.2 mg/kg PCB 126 or corn oil vehicle four days prior to ethanol feeding using the chronic-binge (10-plus-one) model.

RESULTS

Concentrations of macromolecules, including hepatic lipids, carbohydrates, and protein (albumin) were impacted. Exposure to PCB 126 exacerbated hepatic steatosis and hepatomegaly in mice exposed to the chemical and fed an ethanol diet. Gene expression and the analysis of blood chemistry showed a potential net increase and retention of hepatic lipids and reductions in lipid oxidation and clearance capabilities. Depletion of glycogen and glucose was evident, which contributes to disease progression by generating systemic malnutrition. Granulocytic immune infiltrates were present but driven solely by ethanol feeding. Hepatic albumin gene expression and plasma levels were decreased by ~50% indicating a potential compromise of liver function. Finally, gene expression analyses indicated that the aryl hydrocarbon receptor and constitutive androstane receptor were activated by PCB 126 and ethanol, respectively.

CONCLUSIONS

Various environmental toxicants are known to modify or enhance FLD in high-fat diet models. Findings from the present study suggest that they interact with other lifestyle factors such as alcohol consumption to reprogram intermediary metabolism resulting in exacerbated ethanol-associated systemic malnutrition in ALD.

Intestinal toxicity and resistance gene threat assessment of multidrug-resistant Shigella: A novel biotype pollutant

Multidrug-resistant bacteria, especially pathogens, pose a serious threat to disease treatment and recovery, but their potential toxicity to animal development is not entirely clear. As the most important site for nutrient absorption, we studied the intestinal microbiome of Xenopus tropicalis by analyzing the effect of multidrug-resistant Shigella on its intestinal health. Unlike in the control, Shigella intake promoted the secretion of neutral mucus and inhibited intestinal development and weight gain. Following 60 days of exposure, intestinal crypt atrophy, intestinal villus shortening, internal cavity enlargement, and external mucosal muscle disintegration were observed. The circular and longitudinal intestinal muscles became thinner with increasing pathogen exposure. In addition, the presence of Shigella altered the expression of multiple cytokines and classic antioxidant enzyme activities in the gut, which may have caused the intestinal lesions that we observed. 16 S rDNA sequencing analysis of intestinal samples showed that exposure to Shigella destroyed the normal gut microbial abundance and diversity and increased the functional bacterial ratio. Notably, the increased abundance of intestinal antibiotic resistance genes (ARGs) may imply that the resistance genes carried by Shigella easily migrate and transmit within the intestine. Our results expand existing knowledge concerning multidrug-resistant Shigella-induced intestinal toxicity in X. tropicalis and provide new insights for the threat assessment of resistance genes carried by drug-resistant pathogens.

Microplastics and co-pollutant with ciprofloxacin affect interactions between free-floating macrophytes

Microplastic and antibiotic contamination are considered an increasing environmental problem in aquatic systems, while little is known about the impact of microplastics and co-pollutant with antibiotics on freshwater vascular plants, particularly the effects of interactions between macrophytes. Here, we performed a mesocosm experiment to evaluate the impact of polyethylene-microplastics and their co-pollutants with ciprofloxacin on the growth and physiological characteristics of Spirodela polyrhiza and Lemna minor and the interactions between these two macrophytes. Our results showed that microplastics alone cannot significantly influence fresh weight and specific leaf area of the two test free-floating macrophytes, but the effects on photosynthetic pigments, malondialdehyde, catalase and soluble sugar contents were species-specific. Ciprofloxacin can significant adverse effects on the growth and physiological traits of the two test macrophytes and microplastic mitigated the toxicity of ciprofloxacin on the two free-floating plants to a certain extent. In addition, our studies showed that microplastics and co-pollutants can influence relative yield and competitiveness of S. polyrhiza and L. minor by directly or indirectly influencing their physiology and growth. Therefore our findings suggest that species-specific sensibility to microplastic and its co-pollutant among free-floating macrophytes may influence macrophyte population dynamics and thereby community structure and ecosystem functioning. And microplastics altered other contaminant behaviours and toxicity, and may directly or indirectly influence macrophytes interactions and community structure. The present study is the first experimental study exploring the effects of microplastics alone and with their co-pollutants on interactions between free-floating macrophytes, which can provide basic theoretical guidance for improving the stability of freshwater ecosystems.

Plant-pest interactions under the microscope of chemical hormesis

Low doses of contaminants and toxins can stimulate pests feeding on contaminated tissues of host plants and enhance herbivore activity and plant damage. These effects are opposite to those of high toxic doses, have largely been missed so far, and could compromise crop production. Thus, they deserve further consideration and study.

Polystyrene microplastics induce autophagy and apoptosis in birds lungs via PTEN/PI3K/AKT/mTOR

Microplastics (MPs) seriously pollute and potentially threaten human health. Birds are sentinels of environmental pollutants, which respond quickly to contamination events and reveal current environmental exposure. Therefore, birds are good bioindicators for monitoring environmental pollutants. However, the mechanism of lung injury in birds and the role of the PTEN/PI3K/AKT axis are unknown. In this study, broilers treated with different polystyrene microplastics (PS-MPs) (0, 1, 10, and 100 mg/L) were exposed to drinking water for 6 weeks to analyze the effect of PS-MPs on lung injury of broilers. The results showed that with the increase of PS-MPs concentration, malonaldehyde (MDA) content increased, and catalase (CAT) and glutathione (GSH) activity decreased, further leading to oxidative stress. PS-MPs caused the PI3K/Akt/mTOR pathway to be inhibited by phosphorylation, and autophagy accelerated formation (LC3) and degradation (p62), causing autophagy. In PS-MPs exposed lung tissues, the expression of Bax/Bcl-2 and Caspase family increased, and MAPK signaling pathways (p38, ERK, and JNK) showed an increase in phosphorylation level, thus leading to cell apoptosis. Our research showed that PS-MPs could activate the antioxidant system. The antioxidant system unbalance-regulated Caspase family, and PTEN/PI3K/AKT pathways initiated apoptosis and autophagy, which in turn led to lung tissue damage in chickens. These results are of great significance to the toxicological study of PS-MPs and the protection of the ecosystem.

BDE-209 and TCDD enhance metastatic characteristics of melanoma cells after chronic exposure

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and BDE-209 (decabromodiphenyl ether) are persistent organic pollutants (POPs) produced by industrial activities and associated with several diseases. TCDD is a known human carcinogen, but few studies investigated about the effects of exposure to both compounds, i.e., whether BDE-209 and TCDD can render tumor cells more aggressive and metastatic. In the current study we investigated if the exposure of B16-F1 and B16-F10 melanoma murine cells to environmental relevant concentrations of TCDD and BDE-209 at 24 h and 15-day exposure modulates the expression of genes related to metastasis, making the cells more aggressive. Both pollutants did not affect cell viability but lead to increase of cell proliferation, including the upregulation of vimentin, MMP2, MMP9, MMP14 and PGK1 gene expression and downregulation of E-cadherin, TIMP2, TIMP3 and RECK, strongly suggesting changes in cell phenotypes defined as epithelial to mesenchymal transition (EMT) in BDE-209 and TCDD-exposed cells. Foremost, increased expression of metalloproteinases and decreased expression of their inhibitors made B16-F1 cells similar the more aggressive B16-F10 cell line. Also, the higher secretion of extracellular vesicles by cells after acute exposure to BDE-209 could be related with the phenotype changes. These results are a strong indication of the potential of BDE-209 and TCDD to modulate cell phenotype, leading to a more aggressive profile.

Prioritization of micropollutants in municipal wastewater and the joint inhibitory effects of priority organic pollutants on Vibrio qinghaiensis sp.-Q67

Treatment of wastewater in municipal wastewater treatment plants has become a major barrier to organic pollutants entering the aquatic environment. In this study, qualitative screening of organic micropollutants was conducted in a typical municipal wastewater treatment plant (MWWTP) using gas chromatography-mass spectrometry (GC-MS). The identified compounds were prioritized according to their comprehensive scores ranked by detection frequency, semi-quantitative concentration, bioaccumulation, ecotoxicity, and biodegradability. The results showed dibutyl phthalate, antioxidant 2246, methyl stearate, 2,4,6-tri‑tert-butylphenol, and dioctyl phthalate had the top five scores and were ranked as priority organic pollutants in the municipal wastewater. The individual and joint toxicity determinations of the five compounds were carried out by a bioluminescence inhibition assay using Vibrio qinghaiensis sp.-Q67 (V. qinghaiensis). The individual toxicity assay results of these pollutants on V. qinghaiensis demonstrated that the order of the acute toxicity of the five priority organic pollutants was as follows: dioctyl phthalate> dibutyl phthalate> methyl stearate> antioxidant 2246> 2,4,6-tri‑tert-butylphenol. The joint toxicity showed partial addition or antagonism among these pollutants. The prediction results of the mixed toxicity were compared between the concentration addition model and the independent action model, indicating that a single traditional prediction model could not accurately predict the mixed toxicity of different types of organic pollutants, and that a comprehensive application of model prediction could improve the accuracy of mixed toxicity prediction. This method could provide a theoretical basis for systematic screening and toxicity prediction of pollutants in wastewater.

Visible light active graphene oxide modified Ag/Ag2O/BiPO4/Bi2WO6 for photocatalytic removal of organic pollutants and bacteria in wastewater

Wastewater problems caused by antibiotics and bacteria contamination have become the primary environmental concern due to their harm to terrestrial organisms and health risk. To obtain the efficient removal approach of antibiotics and bacteria, visible driven advanced oxidation process by photocatalyst for the efficient removal and reducing waterborne disease was demonstrated in this study. 2D/2D GO-Ag/P/BWO heterostructure photocatalyst (GO: graphene oxide, Ag: Ag, Ag₂O; P: BiPO₄; BWO: Bi₂WO₆) were synthesized for effectively purification of antibiotics and bacteria contaminated wastewater. GO added in synthesis of BWO (1st-hydrothermal) and induced of Ag dopants (2nd-hydrothermal) of GO-Ag/P/BWO were fabricated separately and marked as GO_(I)-Ag/P/BWO and GO_(II)-Ag/P/BWO, characterized by different tests (FT-IR, XRD, Raman, XPS, SEM, TEM, TG, UV-VIS, PL, photocurrent density, and EIS). To testify the visible light driven photocatalytic activity of the fabricated photocatalysts, Rhodamine B (Rh B) and amoxicillin (AMX) was chosen as model emerging organic contaminants and antibiotics, respectively. While gram-negative strain Escherichia coli (E. coli) was selected as model waterborne bacteria. The results showed that GO_(II)-Ag/P/BWO photocatalyst was synthesized successfully, and possessed high crystallinity, low generated electron-hole recombination rate, and high photocurrent density. The system can produce energetic active species (h⁺, O₂^- and OH), exhibiting a superior performance towards removal of Rh B, AMX and E. coli under visible light irradiation. Comparing to other reported GO modified Bi based photocatalyst, GO_(II)-Ag/P/BWO had stronger photocatalytic performance in degradation of Rh B, AMX and E. coli, which indicated its high prospects for practical application in environmental wastewater treatment.

Toxicokinetics and toxicodynamics of plastic and metallic nanoparticles: A comparative study in shrimp

Nanoplastic is recognized as an emerging environmental pollutant due to the anticipated ubiquitous distribution, increasing concentration in the ocean, and potential adverse health effects. While our understanding of the ecological impacts of nanoplastics is still limited, we benefit from relatively rich toxicological studies on other nanoparticles such as nano metal oxides. However, the similarity and difference in the toxicokinetic and toxicodynamic aspects of plastic and metallic nanoparticles remain largely unknown. In this study, juvenile Pacific white shrimp Litopenaeus vannamei was exposed to two types of nanoparticles at environmentally relative low and high concentrations, i.e., 100 nm polystyrene nanoplastics (nano-PS) and titanium dioxide nanoparticles (nano-TiO₂) via dietary exposure for 28 days. The systematic toxicological evaluation aimed to quantitatively compare the accumulation, excretion, and toxic effects of nano-PS and nano-TiO₂. Our results demonstrated that both nanoparticles were ingested by L. vannamei with lower egestion of nano-TiO₂ than nano-PS. Both nanoparticles inhibited the growth of shrimps, damaged tissue structures of the intestine and hepatopancreas, disrupted expression of immune-related genes, and induced intestinal microbiota dysbiosis. Nano-PS exposure caused proliferative cells in the intestinal tissue, and the disturbance to the intestinal microbes was also more serious than that of nano-TiO₂. The results indicated that the effect of nano-PS on the intestinal tissue of L. vannamei was more severe than that of nano-TiO₂ with the same particle size. The study provides new theoretical basis of the similarity and differences of their toxicity, and highlights the current lack of knowledge on various aspects of absorption, distribution, metabolism, and excretion (ADME) pathways of nanoplastics.

Separate and combined effects of cadmium (Cd) and nonylphenol (NP) on growth and antioxidative enzymes in Hydrocharis dubia (Bl.) Backer

Cadmium (Cd) is considered a priority pollutant, and nonylphenol (NP) is a common organic pollutant in water environments. However, the ecological risks of combined Cd and NP pollution have not been fully elucidated. In this study, the effects of Cd, NP, and Cd-NP on the growth and physiology of Hydrocharis dubia (Bl.) Backer were studied. The results indicated that Cd-NP joint toxicity is concentration-dependent. The joint toxicity of Cd and NP on H. dubia was antagonistic when the concentrations of Cd + NP were 0.01 + 0.1/1 mg/L. At 0.5 + 0.1/1 mg/L, Cd and NP had a strong synergistic effect on H. dubia. In addition, plant growth was significantly inhibited, and the chlorophyll contents were significantly reduced under Cd, NP, or Cd-NP exposure. The plant's antioxidant enzyme system was destroyed. The activities of superoxide dismutase (SOD) and catalase (CAT) were significantly decreased under NP-only exposure. The activity of SOD was significantly decreased under Cd-only and under joint exposure. Compound pollution exceeded the oxidative defense capacity of the plants, so the H₂O₂ content increased significantly. Our results indicated that the ecotoxicity of NP combined with Cd may be exacerbated in aquatic environments and cause obvious damage to H. dubia.

Sulphur dioxide and fluoride co-exposure induce incisor hypomineralization and amelogenin upregulation via YAP/RUNX2 signaling pathway

Sulphur dioxide (SO₂) and fluoride are among the most common environmental pollutants affecting human health, and both co-exist in areas predominantly consuming coal. It is vital to analyse the combined toxicity of SO₂ and fluoride, and their effects on health and the underlying mechanisms of their co-exposure have not yet been adequately assessed. In the present study, we used ICR mice and LS8 cells to investigate the toxicity of SO₂ and fluoride exposure to the enamel, alone or in combination. Factorial design analysis was used to reveal the combined toxicity in vitro and in vivo. Co-exposure to SO₂ and fluoride exacerbated enamel injury, resulting in more severe hypomineralization of incisor, and enamel structure disorders in mice, and could induce the accumulation of protein residue in the matrix of the enamel. Amelogenin expression was increased upon exposure to SO₂ and fluoride, but enamel matrix proteases were not affected. Consistent with our in vivo results, co-exposure of SO₂ and fluoride aggravated amelogenin expression in LS8 cells, and increased the YAP and RUNX2 levels. Co-exposure to SO₂ and fluoride resulted in greater toxicity than individual exposure, both in vitro and in vivo, indicating that residents of areas exposed to SO₂ and fluoride may have an increased risk of developing enamel damage.

Effects of nanoplastic exposure on the immunity and metabolism of red crayfish (Cherax quadricarinatus) based on high-throughput sequencing

Previous studies have shown that nanoplastics (NPs) are harmful pollutants that threaten aquatic organisms and ecosystems, however, less research has been conducted on the hazards of NPs for aquaculture animals. In this study, Cherax quadricarinatus was used as an experimental model to evaluate the possible effects of three concentrations (25, 250 and 2500 μg/L) of NPs on red crayfish. The toxicological effects of NPs on this species were investigated based on transcriptomics and microbiome. A total of 67,668 genes were obtained from the transcriptome. The annotation rate of the four major libraries (Nr, KEGG, KOG, Swissprot) was 40.17 %, and the functions of differential genes were mainly related to antioxidant activity, metabolism and immune processes. During the experiment, the activities of superoxide dismutase (SOD) and catalase (CAT) in the high concentration group were significantly decreased, while the concentration of malondialdehyde (MDA) increased after nanoplastics (NPs) exposure, and SOD1, Jafrac1 were significantly reduced at high concentrations. expression is inhibited. The immune genes LYZ and PPO2 were highly expressed at low concentrations and suppressed at high concentrations. After 14 days of exposure to NPs, significant changes in gut microbiota were observed, such as decreased abundances of Actinobacteria, Bacteroidetes, and Firmicutes. NPs compromise host health by inducing changes in microbial communities and the production of beneficial bacterial metabolites. Overall, these results suggest that NPs affect immune-related gene expression and antioxidant enzyme activity in red crayfish and cause redox imbalance in the body, altering the composition and diversity of the gut microbiota.

Acrolein plays a culprit role in the pathogenesis of diabetic nephropathy in vitro and in vivo

OBJECTIVE

Diabetic nephropathy (DN), also known as diabetic kidney disease (DKD), is a major chronic complication of diabetes and is the most frequent cause of kidney failure globally. A better understanding of the pathophysiology of DN would lead to the development of novel therapeutic options. Acrolein, an α,β-unsaturated aldehyde, is a common dietary and environmental pollutant.

DESIGN

The role of acrolein and the potential protective action of acrolein scavengers in DN were investigated using high-fat diet/ streptozotocin-induced DN mice and in vitro DN cellular models.

METHODS

Acrolein-protein conjugates (Acr-PCs) in kidney tissues were examined using immunohistochemistry. Renin-angiotensin system (RAS) and downstream signaling pathways were analyzed using quantitative RT-PCR and Western blot analyses. Acr-PCs in DN patients were analyzed using an established Acr-PC ELISA system.

RESULTS

We found an increase in Acr-PCs in kidney cells using in vivo and in vitro DN models. Hyperglycemia activated the RAS and downstream MAPK pathways, increasing inflammatory cytokines and cellular apoptosis in two human kidney cell lines (HK2 and HEK293). A similar effect was induced by acrolein. Furthermore, acrolein scavengers such as N-acetylcysteine, hydralazine, and carnosine could ameliorate diabetes-induced kidney injury. Clinically, we also found increased Acr-PCs in serum samples or kidney tissues of DKD patients compared to normal volunteers, and the Acr-PCs were negatively correlated with kidney function.

CONCLUSIONS

These results together suggest that acrolein plays a role in the pathogenesis of DN and could be a diagnostic marker and effective therapeutic target to ameliorate the development of DN.

Cadmium induces apoptosis by miR-9-5p targeting PTEN and regulates the PI3K/AKT pathway in the piglet adrenal gland

Cadmium (Cd) is an environmental pollutant that can cause endocrine organ damage. To explore the effect of subacute CdCl₂ exposure on piglet adrenal gland tissue and its mechanism based on the establishment of this model, bioinformatics, TUNEL assay, western blot (WB), and qRT-PCR methods were used to detect related indicators. The results showed that after Cd exposure, antioxidant enzymes decreased, heat shock protein increased, and miR-9-5p-gene of phosphatase and tensin homolog (PTEN) upregulates the phosphatidylinositol-3-kinase (PI3K/AKT) pathway. After this pathway was activated, the expression of the apoptosis-related factors cysteinyl aspartate-specific proteinase 3 and 9 (caspase 3 and 9), B-cell lymphoma-2-associated X (BAX) was increased sharply, and the expression of B-cell lymphoma-2 (BCL2) was significantly decreased. The changes in these indicators indicate that Cd exposure induces apoptosis and causes tissue damage in the adrenal gland of piglets. This study aims to reveal the toxic effects of CdCl₂ in animals and will provide new ideas for the toxicology of Cd.

Protective effect of methionine on the intestinal oxidative stress and microbiota change induced by nickel

Nickel is a common heavy metal pollutant in industrial areas and can cause oxidative damage to human and animal organs. As an essential amino acid with antioxidant function, methionine (Met) may protect the body from the oxidative stress induce by nickel, however, there is not enough research to study in this aspect. The study aims at investigating the effect of Met on the nickel-induced intestinal oxidative stress and further detected the gut microbiota changes. Mice were gavaged with quantitative NiCl₂ (1.6 mg/ml, 0.25 ml) and fed with different doses of methionine in each group. The contents of intestinal oxidation product and antioxidant enzymes were determined by different biochemical quantitative methods, and the data showed that NiCl₂ increased the content of intestinal oxidation product (MDA), and the antioxidant enzymes (GSH-Px, GR, SOD and CAT) were decreased. But this situation was alleviated in the group fed with additional methionine solution (0.5 mg/ml). In addition, we detected changes in the gut microbiota using high-throughput sequencing, the results showed that the structure of intestinal flora was disturbed by NiCl₂, but methionine restored the germs with antioxidant capacity. Based on the results, we speculate that methionine can alleviate the impact of NiCl₂ on the intestinal by enhancing the activity of antioxidant enzymes and the number of gut bacteria with anti-oxidation, suggesting that methionine as a nutritional additive may have the potential to treat nickel poisoning.

Investigating the cytotoxicity of per- and polyfluoroalkyl substances in HepG2 cells: A structure-activity relationship approach

Per- and polyfluoroalkyl substances (PFAS) are a family of man-made chemicals with currently over 4'700 compounds identified. While toxicological data are available for some of the legacy PFAS, such as PFOA and PFOS, a knowledge gap remains concerning both emerging and legacy PFAS' toxicity due to the diversity of the PFAS. Therefore, a better understanding of the PFAS structure-activity relationship may prove helpful. The present study investigated a potential structure-activity relationship between PFAS and hepatotoxicity. As such, the effects of thirteen PFAS with varying carbon chain-length and functional head-groups (in a concentration range of 0-800 µM) on the cell viability of HepG2 cells and intracellular reactive oxygen species formation have been tested using the MTT and DCFH assay, respectively. The exposure times were either 3 or 24 h. In addition, intracellular PFAS levels were determined in HepG2 after 24 h exposure. The present study demonstrated that the cytotoxicity of PFAS is dependent on their chain-length as cell viability decreased with increasing chain-length at both exposure times. Calculated Relative Potency Factors (RPF), based on the TC₅₀ values, were used for a tentative ranking of PFAS regarding their hepatotoxicity: PFNA ˃ PFDA ˃ PFOS ≥ PFOA ˃ PFHxS ˃ PFBS ˃˃ PFHpA = PFHxA = PFBA = PFPrA = 6:2 FTOH = 4:2 = FTOH = 3:1 FTOH. Similar results were observed regarding intracellular reactive oxygen species generation at both exposure times, with a tentative ranking of: PFNA ˃ PFOS ˃ PFOA ≥ PFDA ˃ PFHxS ˃ PFBS ˃ PFBA ˃ PFHpA ≥ PFHxA ˃ PFPrA ˃ 6:2 FTOH = 4:2 FTOH = 3:1 FTOH. Moreover, a concentration-dependent reactive oxygen species generation has been observed for all PFSAs and PFCAs, but not for the FTOHs. In conclusion, the carbon chain-length and functional head-group of a PFAS determine their in vitro toxicity for the two toxicological endpoints assessed in the present study. Moreover, no effects were observed for the tested FTOHs. As such, the present study established a potential structure-activity relationship that opens the possibility of developing a predictive model to help with the risk assessment of PFAS in the future.

Lung toxicity of particulates and gaseous pollutants using ex-vivo airway epithelial cell culture systems

Air pollution consists of a multi-faceted mix of gases and ambient particulate matter (PM) with diverse organic and non-organic chemical components that contribute to increasing morbidity and mortality worldwide. In particular, epidemiological and clinical studies indicate that respiratory health is adversely affected by exposure to air pollution by both causing and worsening (exacerbating) diseases such as chronic obstructive pulmonary disease (COPD), asthma, interstitial pulmonary fibrosis and lung cancer. The molecular mechanisms of air pollution-induced pulmonary toxicity have been evaluated with regards to different types of PM of various sizes and concentrations with single and multiple exposures over different time periods. These data provide a plausible interrelationship between cellular toxicity and the activation of multiple biological processes including proinflammatory responses, oxidative stress, mitochondrial oxidative damage, autophagy, apoptosis, cell genotoxicity, cellular senescence and epithelial-mesenchymal transition. However, these molecular changes have been studied predominantly in cell lines rather than in primary bronchial or nasal cells from healthy subjects or those isolated from patients with airways disease. In addition, they have been conducted under different cell culture conditions and generally in submerged culture rather than the more relevant air-liquid interface culture and with a variety of air pollutant exposure protocols. Cell types may respond differentially to pollution delivered as an aerosol rather than being bathed in media containing agglomerations of particles. As a result, the actual pathophysiological pathways activated by different PMs in primary cells from the airways of healthy and asthmatic subjects remains unclear. This review summarises the literature on the different methodologies utilised in studying the impact of submicron-sized pollutants on cells derived from the respiratory tract with an emphasis on data obtained from primary human cell. We highlight the critical underlying molecular mechanisms that may be important in driving disease processes in response to air pollution in vivo.

Evaluation of the effect of nitrate and chloride on Cd(II)-induced cell oxidative stress by scanning electrochemical microscopy

Cadmium (Cd) is one of the most prevalent toxic metal pollutants, which is widely distributed in various environmental media and organisms. Literature studies have documented that Cd could stimulate cellular oxidative stress, and the increased intracellular reactive oxygen species (ROS) might destroy certain proteins and DNA and subsequently lead to cell apoptosis. Although several studies have studied the co-exposure between cadmium and other metals, information on the potential effects of Cd and its counterions is still lacking. In the present study, we explored the effects of nitrate and chloride on oxidative stress induced by Cd(II) at environmental exposure levels in human breast cancer cells (MCF-7) using scanning electrochemical microscopy (SECM). After incubation in CdCl₂ or Cd(NO₃)₂, ROS production is concentration-dependent and time-dependent, and the variation trend is consistent. When MCF-7 cells were incubated at a constant Cd²⁺ concentration, it was found that the higher the concentration ratio of Cd(NO₃)₂/CdCl₂, the less ROS was generated. Combined with cell-viability, intracellular acidification as well as antioxidants system tests, we observed that nitrate could be reduced to nitrite and then inhibit Cd-induced oxidative stress. Benefitting from real-time in situ imaging of cells by SECM, H₂O₂ was detected and quantified in a noninvasive way, and the effect of Cd at environmental exposure levels on cellular oxidative stress was explored deeper and more comprehensively. Prospectively, cytotoxicological methods based on the SECM technique would be established to explore toxic pollutant co-exposure issues at environmental exposure levels.

Energy-levels well-matched direct Z-scheme ZnNiNdO/CdS heterojunction for elimination of diverse pollutants from wastewater and microbial disinfection

Energy-levels well-matched direct Z-scheme ZnNiNdO/CdS heterojunction was successfully fabricated using facile co-precipitation and ultra-sonication techniques and characterized with XRD, FTIR, Raman, PL, UV-vis, and FE-SEM. The XRD diffractograms confirmed the co-doping of Ni-Nd in ZnO and the formation of heterostructured nanocomposite. FTIR and Raman data showed the presence of metal-oxygen vibration and optical phonon modes of ZnO and CdS. FE-SEM images exhibited the network type morphology. The energy bandgap was redshifted by co-doping (3.37-2.9 eV) and was further reduced (2.6 eV) by making a composite with CdS. The ZnNiNdO/CdS catalyst degraded 99.7, 49, 96.6, 98.6, and 98.6% methylene blue (MB), p-nitroaniline (P-Nitro), methyl orange (MO), methyl red (MR), and rhodamine B (RhB) dyes under 50 min sunlight irradiation. Moreover, ZnNiNdO/CdS showed intense inhibition activity towards Staphylococcus aureus, Escherichia coli, Proteus vulgaris, and Pseudomonas aeruginosa bacterial strains with maximum inhibition zone diameters 30, 33, 27, and 31 mm, respectively. The synergistic effects arising from band alignment can lead to efficient vectorial charge separation, transportation, and lower recombination of photoinduced charge carriers, ultimately boosting photocatalytic and antibacterial performance. The ZnNiNdO/CdS photocatalyst has higher stability up to the 7th cycle towards MB dye with ~ 5% deficit in degradation efficiency. The higher generation of superoxide and hydroxyl radical was confirmed by species trapping experiments responsible for photodegradation of dyes molecules. Furthermore, the results showed that the photocatalytic and antibacterial performance of pristine ZnO can be enhanced by co-doping and tuning energy bandgap.

Effects of exposure to environmental pollutants on mitochondrial DNA copy number: a meta-analysis

Exposure to environmental pollutants has been associated with alteration on relative levels of mitochondrial DNA copy number (mtDNAcn). However, the results obtained from epidemiological studies are inconsistent. This meta-analysis aimed to evaluate whether environmental pollutant exposure can modify the relative levels of mtDNAcn in humans. We performed a literature search using PubMed, Scopus, and Web of Science databases. We selected and reviewed original articles performed in humans that analyzed the relationship between environmental pollutant exposure and the relative levels of mtDNAcn; the selection of the included studies was based on inclusion and exclusion criteria. Only twenty-two studies fulfilled our inclusion criteria. A total of 6011 study participants were included in this systematic review and meta-analysis. We grouped the included studies into four main categories according to the type of environmental pollutant: (1) heavy metals, (2) polycyclic aromatic hydrocarbons (PAHs), (3) particulate matter (PM), and (4) cigarette smoking. Inconclusive results were observed in all categories; the pooled analysis shows a marginal increase of relative levels of mtDNAcn in response to environmental pollutant exposure. The trial sequential analysis and rate confidence in body evidence showed the need to perform new studies. Therefore, a large-scale cohort and mechanistic studies in this area are required to probe the possible use of relative levels of mtDNAcn as biomarkers linked to environmental pollution exposure.

Maternal exposure to the environmental pollutant "BDE-47" impairs the postnatal development of rat cerebellar cortex by modulating neuronal proliferation, synaptogenesis, NGF and BDNF pathways

2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) is an environmental contaminant that crosses the blood placental barrier and interferes with the homeostasis of fetal thyroid hormones.

AIM OF WORK

This study was designed to investigate the perinatal effect of BDE-47 exposure on the postnatal development of the rat cerebellar cortex.

MATERIALS AND METHODS

This study was carried out on 20 pregnant rats and 36 of their offspring. The pregnant rats were divided equally into control and BDE-47 treated mother groups; supplemented orally with BDE-47 (0.2 mg/kg/day from day 8 of gestation until the day of weaning). The offspring of both mother groups were subdivided, according to their developmental age, into three subgroups; PND14, PND21and PND42. SerumT3, T4 and TSH were assessed for dams and their offspring. Testing the motor coordination of the offspring via the rotarod test was conducted. Sections of the cerebellar cortex from offspring subgroups were stained with hematoxylin and eosin alongside immunohistochemical reactions and optical density of nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), proliferating cell nuclear antigen (PCNA) and synaptophysin (SYN). Also, the thickness of different layers of the cerebellar cortex was histomorphometrically measured.

RESULTS

BDE-47 treated mothers and their offspring subgroups showed a significant decrease in the serum free T3, T4 and increased TSH. The BDE-47 offspring displayed incoordination of the motor activity together with disturbed cytoarchitecture of the cerebellar cortical layers, and impaired migration of its germinative neuronal zones, particularly on PND14 and PND21. Moreover, these offspring displayed a decrease of the immune-expression and optical density of NGF, BDNF in the cerebellar cortical layers with impaired proliferation, and synaptogenesis.

CONCLUSION

Maternal exposure to BDE-47 during pregnancy and lactation effectuated a potential deleterious retarding effect on the postnatal development of the rat cerebellar cortex mostly via modulating neuronal proliferation, synaptogenesis, NGF and BDNF pathways secondary to its hypothyroid effect.

Detection and identification of hazardous organic pollutants from distillery wastewater by GC-MS analysis and its phytotoxicity and genotoxicity evaluation by using Allium cepa and Cicer arietinum L

Distillery industry generates a huge amount of wastewater, which contains a high strength of organic and inorganic load. Accordingly, this study aims to analyze the physico-chemical pollution parameters and the occurrence of phytotoxic, cytotoxic and genotoxic pollutants in wastewater. The result revealed that values of wastewater parameters were recorded as 13268 mg l^-1 (BOD), 25144 mg l^-1 (COD), 25144 mg l^-1 (TS), and 6634 mg l^-1 (phosphate), while pH was alkaline. The organic compounds detected by GC-MS were quercetin 7,3',4'-trimethoxy, octadecadienoic acid, propanoic acid, glycocholic acid methyl ester, cantaxanthin, etc. The Allium cepa was used for the toxicity test with different concentrations of wastewater showed a significant level of reduction in root growth and length after exposure and the maximum reduction was at 25% and 20%. Phytotoxicity studies were performed using Cicer arietinum L. with different concentrations of wastewater, which showed adverse effects on seed germination, root length, and the effect was associated with the increasing concentration of wastewater. A. cepa root tips were used for the analysis of mitotic index (MI), nuclear abnormalities (NA), and chromosomal aberrations (CA). MI was decreasing significantly from 72% (control) to 33%, 22%, 23%, 21%, and 18% at 5%, 10%, 15%, 20%, and 25% wastewater concentration, respectively. The A. cepa root tip cells showed chromosomal aberrations and nuclear abnormalities like vagrant, stickiness, chromosomal loss, c-mitosis, binucleated, micronuclei, and aberrant cell. This study concluded that the wastewater treatment process is insufficient and the discharged waste needs a proper assessment to know the associated health risk.

Intrauterine exposure of mice to arsenite induces abnormal and transgenerational glycometabolism

The adverse, transgenerational effects on health caused by environmental pollutants are receiving increasing attention. For humans and mice, inorganic arsenic (iAs), a widespread environmental contaminant, is associated with diabetic phenotypes. However, the transgenerational effects of arsenite-induced changes in glucose metabolism in mice have not been fully investigated. In the present study, F0 pregnant mice were exposed to arsenite via drinking water (0, 0.5, 5, or 50 ppm NaAsO₂) from gestational day 0 (GD0) until parturition. We examined the effects of arsenite exposure on the metabolic phenotypes and the levels of proteins and genes related to glucose metabolism of dams and their offspring (F1∼F4). Arsenite exposure altered the glucose tolerance of offspring. Notably, glucose transporter-2 (GLUT2) and insulin receptor substrate-1 (IRS1), which are related to the maintenance of glucose homeostasis, were also changed. The homeostasis assessment-insulin resistance (HOMA-IR), an indicator of insulin resistance, was higher in the offspring from the F0 female mice exposed to arsenite. Furthermore, imprinted genes, insulin-like growth factor 2 (IGF2) and potassium voltage-gated channel subfamily Q member 1 (KCNQ1), related to glycometabolism across multiple generations, were lower in the offspring. In sum, arsenite exposure during pregnancy transgenerationally affects glucose metabolism, which is related to altered levels of IGF2 and KCNQ1.

Nanoplastics and Arsenic Co-Exposures Exacerbate Oncogenic Biomarkers under an In Vitro Long-Term Exposure Scenario

The increasing accumulation of plastic waste and the widespread presence of its derivatives, micro- and nanoplastics (MNPLs), call for an urgent evaluation of their potential health risks. In the environment, MNPLs coexist with other known hazardous contaminants and, thus, an interesting question arises as to whether MNPLs can act as carriers of such pollutants, modulating their uptake and their harmful effects. In this context, we have examined the interaction and joint effects of two relevant water contaminants: arsenic and polystyrene nanoplastics (PSNPLs), the latter being a model of nanoplastics. Since both agents are persistent pollutants, their potential effects have been evaluated under a chronic exposure scenario and measuring different effect biomarkers involved in the cell transformation process. Mouse embryonic fibroblasts deficient for oxidative DNA damage repair mechanisms, and showing a cell transformation status, were used as a sensitive cell model. Such cells were exposed to PSNPLs, arsenic, and a combination PSNPLs/arsenic for 12 weeks. Interestingly, a physical interaction between both pollutants was demonstrated by using TEM/EDX methodologies. Results also indicate that the continuous co-exposure enhances the DNA damage and the aggressive features of the initially transformed phenotype. Remarkably, co-exposed cells present a higher proportion of spindle-like cells within the population, an increased capacity to grow independently of anchorage, as well as enhanced migrating and invading potential when compared to cells exposed to arsenic or PSNPLs alone. This study highlights the need for further studies exploring the long-term effects of contaminants of emerging concern, such as MNPLs, and the importance of considering the behavior of mixtures as part of the hazard and human risk assessment approaches.

PFAS and Potential Adverse Effects on Bone and Adipose Tissue Through Interactions With PPARγ

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a widely dispersed, broad class of synthetic chemicals with diverse biological effects, including effects on adipose and bone differentiation. PFAS most commonly occur as mixtures and only rarely, if ever, as single environmental contaminants. This poses significant regulatory questions and a pronounced need for chemical risk assessments, analytical methods, and technological solutions to reduce the risk to public and environmental health. The effects of PFAS on biological systems may be complex. Each may have several molecular targets initiating multiple biochemical events leading to a number of different adverse outcomes. An exposure to mixtures or coexposures of PFAS complicates the picture further. This review illustrates how PFAS target peroxisome proliferator-activated receptors. Additionally, we describe how such activation leads to changes in cell differentiation and bone development that contributes to metabolic disorder and bone weakness. This discussion sheds light on the importance of seemingly modest outcomes observed in test animals and highlights why the most sensitive end points identified in some chemical risk assessments are significant from a public health perspective.