PM2.5 exposure contributes to anxiety and depression-like behaviors via phenyl-containing compounds interfering with dopamine receptor.

As a global problem, fine particulate matter (PM2.5) really needs local fixes. Considering the increasing epidemiological relevance to anxiety and depression but inconsistent toxicological results, the most important question is to clarify whether and how PM2.5 causally contributes to these mental disorders and which components are the most dangerous for crucial mitigation in a particular place. In the present study, we chronically subjected male mice to a real-world PM2.5 exposure system throughout the winter heating period in a coal combustion area and revealed that PM2.5 caused anxiety and depression-like behaviors in adults such as restricted activity, diminished exploratory interest, enhanced repetitive stereotypy, and elevated acquired immobility, through behavioral tests including open field, elevated plus maze, marble-burying, and forced swimming tests. Importantly, we found that dopamine signaling was perturbed using mRNA transcriptional profile and bioinformatics analysis, with Drd1 as a potential target. Subsequently, we developed the Drd1 expression-directed multifraction isolating and nontarget identifying framework and identified a total of 209 compounds in PM2.5 organic extracts capable of reducing Drd1 expression. Furthermore, by applying hierarchical characteristic fragment analysis and molecular docking and dynamics simulation, we clarified that phenyl-containing compounds competitively bound to DRD1 and interfered with dopamine signaling, thereby contributing to mental disorders. Taken together, this work provides experimental evidence for researchers and clinicians to identify hazardous factors in PM2.5 and prevent adverse health outcomes and for local governments and municipalities to control source emissions for diminishing specific disease burdens.

Retinal Degeneration Response to Graphene Quantum Dots: Disruption of the Blood-Retina Barrier Modulated by Surface Modification-Dependent DNA Methylation.

Graphene quantum dots (GQDs) are used in diverse fields from chemistry-related materials to biomedicines, thus causing their substantial release into the environment. Appropriate visual function is crucial for facilitating the decision-making process within the nervous system. Given the direct interaction of eyes with the environment and even nanoparticles, herein, GQDs, sulfonic acid-doped GQDs (S-GQDs), and amino-functionalized GQDs (A-GQDs) were employed to understand the potential optic neurotoxicity disruption mechanism by GQDs. The negatively charged GQDs and S-GQDs disturbed the response to light stimulation and impaired the structure of the retinal nuclear layer of zebrafish larvae, causing vision disorder and retinal degeneration. Albeit with sublethal concentrations, a considerably reduced expression of the retinal vascular sprouting factor sirt1 through increased DNA methylation damaged the blood-retina barrier. Importantly, the regulatory effect on vision function was influenced by negatively charged GQDs and S-GQDs but not positively charged A-GQDs. Moreover, cluster analysis and computational simulation studies indicated that binding affinities between GQDs and the DNMT1-ligand binding might be the dominant determinant of the vision function response. The previously unknown pathway of blood-retinal barrier interference offers opportunities to investigate the biological consequences of GQD-based nanomaterials, guiding innovation in the industry toward environmental sustainability.

Triazole fungicides disrupt embryonic stem cell differentiation: Potential modulatory role of the retinoic acid signaling pathway.

The developmental toxicity and human health risks of triazole fungicides (TFs) have attracted worldwide attention due to the ability to enter the human body in a variety of ways. Nevertheless, the specific mechanism by which TFs exert remains incompletely understood. Given that retinoic acid (RA) signaling pathway are closely related to development, this study aimed to screen and identify developmentally disabled chemicals in commonly used TFs and to reveal the potential effects of TFs on developmental retardation through the RA signaling pathway in mouse embryonic stem cells (mESCs). Specifically, six typical TFs (myclobutanil, tebuconazole, hexaconazole, propiconazole, difenoconazole, and flusilazole) were exposed through the construction of an embryoid bodies (EBs)-based in vitro global differentiation models. Our results clarified that various TFs disturbed lineage commitment during early embryonic development. Crucially, the activation of RA signaling pathway, which alters the expression of key genes and interferes the transport and metabolism of retinol, may be responsible for this effect. Furthermore, molecular docking, molecular dynamics simulations, and experiments using a retinoic acid receptor α inhibitor provide evidence supporting the potential modulatory role of the retinoic acid signaling pathway in developmental injury. The current study offers new insights into the TFs involved in the RA signaling pathway that interfere with the differentiation process of mESCs, which is crucial for understanding the impact of TFs on pregnancy and early development.

Perfluorinated Iodine Alkanes Promoted Neural Differentiation of mESCs by Targeting miRNA-34a-5p in Notch-Hes Signaling.

The neurodevelopmental process is highly vulnerable to environmental stress from exposure to endocrine-disrupting chemicals. Perfluorinated iodine alkanes (PFIs) possess estrogenic activities, while their potential neurodevelopmental toxicity remains blurry. In the present study, the effects of two PFIs, including dodecafluoro-1,6-diiodohexane (PFHxDI) and tridecafluorohexyl iodide (PFHxI), were investigated in the neural differentiation of the mouse embryonic stem cells (mESCs). Without influencing the cytobiological process of the mESCs, PFIs interfered the triploblastic development by increasing ectodermal differentiation, thus promoting subsequent neurogenesis. The temporal regulation of PFIs in Notch-Hes signaling through the targeting of mmu-miRNA-34a-5p provided a substantial explanation for the underlying mechanism of PFI-promoted mESC commitment to the neural lineage. The findings herein provided new knowledge on the potential neurodevelopmental toxicities of PFIs, which would help advance the health risk assessment of these kinds of emerging chemicals.

Graphene Quantum Dots Disrupt Embryonic Stem Cell Differentiation by Interfering with the Methylation Level of Sox2.

The tremendous potential for graphene quantum dots (GQDs) in biomedical applications has led to growing concerns of their health risks in human beings. However, present studies mainly focused on oxidative stress, apoptosis, and other general toxicity effects; the knowledge on the developmental toxicity and the related regulatory mechanisms is still far from sufficient. Our study revealed the development retardation of mouse embryonic stem cells (mESCs) caused by GQDs with a novel DNA methylation epigenetic mechanism. Specifically, GQDs were internalized into cells mainly via energy-dependent endocytosis, and a significant fraction of internalized GQDs remained in the cells even after a 48-h clearance period. Albeit with unobservable cytotoxicity or any influences on cell pluripotency, significant retardation was found in the in vitro differentiation of the mESCs into embryoid bodies (EBs) with the upregulation of Sox2 levels in GQD pretreatment groups. Importantly, this effect could be contributed by GQD-induced inhibition in CpG methylation of Sox2 through altering methyltransferase and demethyltransferase transcriptional expressions, and the demethyltransferase inhibitor, bobcat339 hydrochloride, reduced GQD-induced upregulation of Sox2. The current study first demonstrated that GQDs compromised the differentiation program of the mESCs, potentially causing development retardation. Exposure to this nanomaterial during gestation or early developmental period would cause adverse health risks and is worthy of more attention.

Tebuconazole induces liver injury coupled with ROS-mediated hepatic metabolism disorder.

Tebuconazole, the most widely used fungicide, is reported to cause various environmental problems and have serious health risks in humans. Despite numerous advances in toxicity studies, its internal metabolic process and the underlying mechanisms have not been systemically studied. The present study administered low doses (0.02 g/kg bw and 0.06 g/kg bw) of tebuconazole to C57BL/6 mice in vivo. The high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed and validated to analyze the tebuconazole in different organs, and our data revealed that tebuconazole mainly accumulated in the liver and that histopathological damage were exhibited in this organ. Tebuconazole significantly dysregulated phase Ⅰ- and phase II-metabolizing enzymes, ATP-binding cassette (ABC) efflux transporters (Abcc2 and Abcc3) and fatty acid metabolism-related genes (Cdkn1a and Fasn), thereby directly causing liver hypertrophy and steatosis. Importantly, the excessive induction of reactive oxygen species (ROS) and oxidative stress partially accounted for the metabolic abnormalities mediated by tebuconazole. Moreover, these alterations were related to the abnormal transcriptional levels of peroxisome proliferator-activated receptor α (PPAR-α) and liver x receptor α (LXR-α), which were predicted to bind to tebuconazole via hydrogen bonding interactions. The current findings provide new insight into the molecular mechanisms of metabolic abnormalities induced by tebuconazole at low concentration, and are conducive to a better understanding of the environmental risk posed by this fungicide.

Investigating photo-driven arsenics' behavior and their glucose metabolite toxicity by the typical metallic oxides in ambient PM2.5.

It is essential and challenged to understand the atmospheric arsenic pollution because it is much more complicated than in water and top-soil. Herein the different behavior of arsenic species firstly were discovered within the ambient PM2.5 collected during daytime and nighttime, winter and summer. The diurnal variation of arsenic species in PMs is significantly correlated with the presence of metallic oxides, specifically, ferrous, titanium and zinc oxides, which might play a key role in the process of the photo-oxidation of As(III) to As(V) with the meteorological parameters and regional factors excluded. Subsequently, the photo conversion of arsenite was detected on metal-loaded glass-fiber filters under visible light. The photo-generated superoxide radical was found to be predominantly responsible for the oxidation of As(III). In order to reveal toxicity differences induced by oxidation As(III), HepG2 cells were exposed to various arsenic mixture solution. We found that the antioxidant enzyme activities suppressed with increasing the As(III)/As(V) ratio in total, followed by the accumulation of intracellular ROS level. The glucose consumption and glycogen content also displayed an obvious reduction in insulin-stimulated cells. Compared to the expression levels of IRS-1, AKT and GLUT4, GLUT2 might be more vulnerable to arsenic exposure and lead to the abnormalities of glucose metabolism in HepG2 cells. Taken together, these findings clarify that the health risk posed by inhalation exposure to As-pollution air might be alleviated owing to the photo-driven conversion in presence of metal oxides.

PM2.5 exposure induces age-dependent hepatic lipid metabolism disorder in female mice.

Particulate matter exposure has been described to elevate the risk of lung and cardiovascular diseases. An increasing number of recent studies have indicated positive correlations between PM2.5 (the fraction of airborne particles with an aerodynamic diameter less than 2.5 µm) exposure and the risk of liver diseases. However, research on the effects of PM2.5 exposure on liver fat synthesis, secretion, and clearance mechanisms under normal diet conditions is limited, and whether these effects are age-dependent is largely unknown. Female C57BL/6 mice at different ages (4 weeks (4 w), 4 months (4 m), and 10 months (10 m)) were treated with 3 mg/kg body weight of PM2.5 every other day for 4 weeks. Subsequently, the ultrastructural changes of liver, the expression of genes involved in oxidative damage and lipid metabolism in the liver were examined. Observation of hepatic ultrastructure showed more and larger lipid droplets in the livers of 4-week-old and 10-month-old mice exposed to PM2.5. Further analysis showed that PM2.5 exposure increased the expression of genes related to lipid synthesis, but decreased the expression of genes involved in lipid transport and catabolism in the livers of 10-month-old mice. Our findings suggest that exposure to PM2.5 disrupts the normal metabolism of liver lipids and induces lipid accumulation in the liver of female mice in an age-dependent manner, with older mice being more susceptible to PM2.5.

Comprehensive hippocampal metabolite responses to PM2.5 in young mice.

Fine particulate matter (PM2.5) exposure alters brain development, clinical cognition and behavior in childhood. Previous studies of this subject have mainly been epidemiological investigations or analyses of gene and protein levels; however, gas chromatography-mass spectrometry (GC-MS)-based metabolic profiling, which will help clarify the molecular mechanisms of susceptibility in PM2.5-induced neurotoxicity, is lacking. In the present study, C57BL/6 mice at different ages (4 weeks, 4 months and 10 months) received oropharyngeal aspiration of PM2.5 (3 mg/kg) every other day for 4 weeks. The Morris water maze showed that PM2.5 exposure caused deterioration of spatial learning and memory in young (4 week old) mice. In addition, the levels of several metabolites belonging to different metabolite classes were significantly changed by PM2.5 exposure in 4-week-old mice. Based on metabolic pathway analysis, we speculated that the decline in spatial learning and memory due to PM2.5 exposure may be directly or indirectly associated with hippocampal region-specific metabolic alterations involving energy metabolism (citric acid, succinic acid, malic acid, maltose and creatinine); cholesterol metabolism (desmosterol, lanosterol and campesterol); arachidonic acid metabolism (methyl arachidonic acid, nonanoic acid and linoleic acid); inositol phosphate metabolism (myo-inositol, myo-inositol-1-phosphate and methyl-phosphate) and aspartic acid metabolism (aspartic acid, asparagine and homoserine).

NF-κB-regulated microRNA-574-5p underlies synaptic and cognitive impairment in response to atmospheric PM2.5 aspiration.

BACKGROUND: PM2.5 (particulate matter ≤ 2.5 µm) is one of the leading environmental risk factors for the global burden of disease. Whereas increasing evidence has linked the adverse roles of PM2.5 with cardiovascular and respiratory diseases, limited but growing emerging evidence suggests that PM2.5 exposure can affect the nervous system, causing neuroinflammation, synaptic dysfunction and cognitive deterioration. However, the molecular mechanisms underlying the synaptic and cognitive deficits elicited by PM2.5 exposure are largely unknown. METHODS: C57BL/6 mice received oropharyngeal aspiration of PM2.5 (1 and 5 mg/kg bw) every other day for 4 weeks. The mice were also stereotaxically injected with ß-site amyloid precursor protein cleaving enzyme 1 (ß-secretase, BACE1) shRNA or LV-miR-574-5p lentiviral constructs in the absence or presence of PM2.5 aspiration at 5 mg/kg bw every other day for 4 weeks. Spatial learning and memory were assessed with the Morris water maze test, and synaptic function integrity was evaluated with electrophysiological recordings of long-term potentiation (LTP) and immunoblot analyses of glutamate receptor subunit expression. The expression of α-secretase (ADAM10), BACE1, and γ-secretase (nicastrin) and the synthesis and accumulation of amyloid ß (Aß) were measured by immunoblot and enzyme-linked immunosorbent assay (ELISA). MicroRNA (miRNA) expression was screened with a microRNA microarray analysis and confirmed by real-time quantitative reverse transcription PCR (qRT-PCR) analysis. Dual-luciferase reporter gene and chromatin immunoprecipitation (ChIP) analyses were used to detect the binding of miR-574-5p in the 3'UTR of BACE1 and NF-κB p65 in the promoter of miR-574-5p, respectively. RESULTS: PM2.5 aspiration caused neuroinflammation and deteriorated synaptic function integrity and spatial learning and memory, and the effects were associated with the induction of BACE1. The action was mediated by NF-κB p65-regulated downregulation of miR-574-5p, which targets BACE1. Overexpression of miR-574-5p in the hippocampal region decreased BACE1 expression, restored synaptic function, and improved spatial memory and learning following PM2.5 exposure. CONCLUSIONS: Taken together, our findings reveal a novel molecular mechanism underlying impaired synaptic and cognitive function following exposure to PM2.5, suggesting that miR-574-5p is a potential intervention target for the prevention and treatment of PM2.5-induced neurological disorders.

Abnormal energy metabolism and tau phosphorylation in the brains of middle-aged mice in response to atmospheric PM2.5 exposure.

In light of the accelerated aging of the global population and the deterioration of the atmosphere pollution, we sought to clarify the potential mechanisms by which fine particulate matter (PM2.5) can cause cognitive impairment and neurodegeneration through the alteration of mitochondrial structure and function. The results indicate that PM2.5 inhalation reduces ATP production by disrupting the aerobic tricarboxylic acid cycle and oxidative phosphorylation, thereby causing the hypophosphorylation of tau in the cortices of middle-aged mice. Furthermore, excessive reactive oxygen species generation was involved in the impairment. Interestingly, these alterations were partially reversed after exposure to PM2.5 ended. These findings clarify the mechanism involved in mitochondrial abnormality-related neuropathological dysfunction in response to atmospheric PM2.5 inhalation and provide an optimistic sight for alleviating the adverse health outcomes in polluted areas.

Inflammatory response and endothelial dysfunction in the hearts of mice co-exposed to SO2 , NO2 , and PM2.5.

SO2 , NO2 , and PM2.5 are typical air pollutants produced during the combustion of coal. Increasing evidence indicates that air pollution has contributed to the development and progression of heart-related diseases over the past decades. However, little experimental data and few studies of SO2 , NO2 , and PM2.5 co-exposure in animals exist; therefore, the relevant mechanisms underlying this phenomenon are unclear. An important characteristic of air pollution is that co-exposure persists at a low concentration throughout a lifetime. In the present study, we treated adult mice with SO2 , NO2 , and PM2.5 at various concentrations (0.5 mg/m3 SO2 , 0.2 mg/m3 NO2 6 h/d, with intranasal instillation of 1 mg/kg PM2.5 every other day during these exposures; or 3.5 mg/m3 SO2 , 2 mg/m3 NO2 6 h/d, and 10 mg/kg PM2.5 for 28 d). Blood pressure (BP), heart rate (HR), histopathological damage, and inflammatory and endothelial cytokines in the heart were assessed. The results indicate that co-exposure caused endothelial dysfunction by elevating endothelin-1 (ET-1) expression and repressing the endothelial nitric oxide synthase (eNOS) level as well as stimulating the inflammatory response by increasing the levels of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Additionally, these alterations were confirmed by histological staining. Furthermore, we observed decreased BP and increased HR after co-exposure. Our results indicate that co-exposure to SO2 , NO2 , and PM2.5 may be a major risk factor for cardiac disease and may induce injury to the hearts of mammals and contribute to heart disease. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1996-2005, 2016.

Characterization of synergistic embryotoxicity of nickel and buprofezin in zebrafish.

Multiple pollutants, usually at low levels, coexist and may interact in the environment. It is therefore important to analyze the toxicity of mixtures of coexisting chemicals to evaluate the potential ecological risk. Concern regarding the co-occurrence and combined bioeffects of heavy metals and organic insecticides in aquatic settings has existed for many years, but a clear understanding of the interactions between and potential combined toxicity of these chemicals remains elusive. In the present study, the combined effects of the heavy metal nickel (NiSO4) and insect growth regulator buprofezin on the induction of embryo toxicity in zebrafish were assessed. By applying nonlinear regression to the concentration-response data with each of the chemicals using the Hill and Langmuir functions and computing the predictions using the model of concentration addition (CA), we confirmed that NiSO4 and buprofezin acted together to produce synergistic embryotoxicity in zebrafish. Subsequently, we further found that the combination of NiSO4 and buprofezin formed a complex that facilitated the uptake of nickel (Ni) and buprofezin by the embryos. Following this, we clarified that an oxidative mechanism of the complex might underlie the synergistic embryotoxicity of NiSO4 and buprofezin.

Cross-Omics Analyses Reveal the Effects of Ambient PM2.5 Exposure on Hepatic Metabolism in Female Mice.

Ambient particulate matter (PM2.5) is a potential risk factor for metabolic damage to the liver. Epidemiological studies suggest that elevated PM2.5 concentrations cause changes in hepatic metabolism, but there is a lack of laboratory evidence. Here, we aimed to evaluate the effects of PM2.5 exposure on liver metabolism in C57BL/6j female mice (10 months old) and to explore the mechanisms underlying metabolic alterations and differential gene expressions by combining metabolomics and transcriptomics analyses. The metabolomics results showed that PM2.5 exposure notably affected the metabolism of amino acids and organic acids and caused hepatic lipid and bile acid accumulation. The transcriptomic analyses revealed that PM2.5 exposure led to a series of metabolic pathway abnormalities, including steroid biosynthesis, steroid hormone biosynthesis, primary bile acid biosynthesis, etc. Among them, the changes in the bile acid pathway might be one of the causes of liver damage in mice. In conclusion, this study clarified the changes in liver metabolism in mice caused by PM2.5 exposure through combined transcriptomic and metabolomic analyses, revealed that abnormal bile acid metabolism is the key regulatory mechanism leading to metabolic-associated fatty liver disease (MAFLD) in mice, and provided laboratory evidence for further clarifying the effects of PM2.5 on body metabolism.

Metastatic effects of hydroxy-polycyclic aromatic hydrocarbons on liver cancer cells mediated by estrogen receptor α.

Hydroxy-polycyclic aromatic hydrocarbons (OH-PAHs) are a growing worldwide concern because of their persistence, ubiquity, and toxicity. Nonetheless, research on the toxicological mechanisms of OH-PAHs remains sparse, particularly concerning the risk of liver cancer. This study evaluated the effects of OH-PAHs on disrupting estrogen receptor α (ERα) and subsequently facilitating hepatocellular invasion and metastasis. Results revealed that all six OH-PAHs exhibited ERα agonistic activities at noncytotoxic levels, which were partially validated using molecular docking (MD) and molecular dynamics simulations (MDS). Furthermore, OH-PAHs with ERα agonistic properties stimulated a concentration-dependent increase in the migration and invasion of HepG2 cells. In addition, they disturbed the expression of target genes associated with epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM), and the invasion effects were significantly reversed by adding an ERα antagonist. Our results suggest an essential role of ERα in the metastasis of liver cancer cells induced by OH-PAHs and emphasize their potential ecological and health hazards.

Developmental Toxicity of Fine Particulate Matter: Multifaceted Exploration from Epidemiological and Laboratory Perspectives.

Particulate matter of size ≤ 2.5 µm (PM2.5) is a critical environmental threat that considerably contributes to the global disease burden. However, accompanied by the rapid research progress in this field, the existing research on developmental toxicity is still constrained by limited data sources, varying quality, and insufficient in-depth mechanistic analysis. This review includes the currently available epidemiological and laboratory evidence and comprehensively characterizes the adverse effects of PM2.5 on developing individuals in different regions and various pollution sources. In addition, this review explores the effect of PM2.5 exposure to individuals of different ethnicities, genders, and socioeconomic levels on adverse birth outcomes and cardiopulmonary and neurological development. Furthermore, the molecular mechanisms involved in the adverse health effects of PM2.5 primarily encompass transcriptional and translational regulation, oxidative stress, inflammatory response, and epigenetic modulation. The primary findings and novel perspectives regarding the association between public health and PM2.5 were examined, highlighting the need for future studies to explore its sources, composition, and sex-specific effects. Additionally, further research is required to delve deeper into the more intricate underlying mechanisms to effectively prevent or mitigate the harmful effects of air pollution on human health.

Triazole fungicides exert neural differentiation alteration through H3K27me3 modifications: In vitro and in silico study.

Considering that humans are unavoidably exposed to triazole fungicides through the esophagus, respiratory tract, and skin contact, revealing the developmental toxicity of triazole fungicides is vital for health risk assessment. This study aimed to screen and discriminate neural developmental disorder chemicals in commonly used triazole fungicides, and explore the underlying harmful impacts on neurogenesis associated with histone modification abnormality in mouse embryonic stem cells (mESCs). The triploblastic and neural differentiation models were constructed based on mESCs to expose six typical triazole fungicides (myclobutanil, tebuconazole, hexaconazole, propiconazole, difenoconazole, and flusilazole). The result demonstrated that although no cytotoxicity was observed, different triazole fungicides exhibited varying degrees of alterations in neural differentiation, including increased ectodermal differentiation, promoted neurogenesis, increased intracellular calcium ion levels, and disturbance of neurotransmitters. Molecular docking, cluster analysis, and multiple linear regressions demonstrated that the binding affinities between triazole fungicides and the Kdm6b-ligand binding domain were the dominant determinants of the neurodevelopmental response. This partially resulted in the reduced enrichment of H3K27me3 at the promoter region of the serotonin receptor 2 C gene, finally leading to disturbed neural differentiation. The data suggested potential adverse outcomes of triazole fungicides on embryonic neurogenesis even under sublethal doses through interfering histone modification, providing substantial evidence on the safety control of fungicides.

Tebuconazole mediates cognitive impairment via the microbe-gut-brain axis (MGBA) in mice.

Tebuconazole, one of the most widely used triazole fungicides, is reported to potentially pose a risk of inducing neurological disorders in human beings. Considering the increasing exposure, whether it could influence cognitive function remains to be elucidated. Herein, we used a mouse model to evaluate the potential cognitive risks and possible mechanisms from the continuous edible application of tebuconazole at low concentrations. Our study revealed that tebuconazole deteriorated spatial learning and memory and downregulated the expression of glutamate receptor subunits. Importantly, metagenomic analysis indicated that tebuconazole not only led to significant shifts in the composition and diversity of the gut microbiota but also changed intestinal homeostasis. Specifically, after exposure, tebuconazole circulated in the bloodstream and largely entered the gut-brain axis for disruption, including disturbing the Firmicutes/Bacteroidetes ratio, interrelated neurotransmitters and systemic immune factors. Moreover, pretreatment with probiotics improved immune factor expression and restored the deterioration of synaptic function and spatial learning and memory. The current study provides novel insights concerning perturbations of the gut microbiome and its functions as a potential new mechanism by which tebuconazole exposes cognitive function-related human health.

Constructing an MCF-7 breast cancer cell-based transient transfection assay for screening RARα (Ant)agonistic activities of emerging phenolic compounds.

The screening of compounds with endocrine disrupting effects has been attracting increasing attention due to the continuous release of emerging chemicals into the environment. Testing the (ant)agonistic activities of these chemicals on the retinoic acid receptor α (RARα), a vital nuclear receptor, is necessary to explain their perturbation in the endocrine system in vivo. In the present study, MCF-7 breast carcinoma cells were transiently transfected with a RARα expression vector (pEF1α-RARα-RFP) and a reporter vector containing a retinoic acid reaction element (pRARE-TA-Luc). Under optimized conditions, the performance of the newly constructed system was evaluated for its feasibility in screening the (ant)agonistic effects of emerging phenolic compounds on RARα. The results showed that this transient transfection cell model responded well to stimulation with (ant)agonists of RARα, and the EC50 and IC50 values were 0.87 nM and 2.67 µM for AM580 and Ro41-5253, respectively. Its application in testing several emerging phenolic compounds revealed that triclosan (TCS) and tetrabromobisphenol A (TBBPA) exerted notable RARα antagonistic activities. This newly developed bioassay based on MCF-7 is promising in identifying the agonistic or antagonistic activities of xenobiotics on RARα and has good potential for studying RARα signaling-involved toxicological effects of emerging chemicals of concern.