Neurodevelopmental exposure to chlorpyrifos (CPF) could increase risks for neurological disorders, such as autism spectrum disorder, cognitive impairment, or attention deficit hyperactivity disorder. The potential involvement of microglia reactive to inflammatory stimuli in these neurological disorders has been generally reported. However, the concrete effects and potential mechanisms of microglia dysfunction triggered by developmental CPF exposure remain unclear. Therefore, we established mouse and human embryonic microglial cells (HMC3 cell) models of developmental CPF exposure to evaluate the effects of developmental CPF exposure on neuroinflammation and underlying mechanisms. The results showed that developmental exposure to CPF enhanced the expression of Iba1 in hippocampus. CPF treatment increased inflammatory cytokines levels and TSPO expression in hippocampus and HMC3 cells. The levels of necroptosis and necroptosis-related signaling RIPK/MLKL were increased in hippocampus and HMC3 cells following CPF exposure. Furthermore, the expression of TLR4/TRIF signaling was increased in hippocampus and HMC3 cells subjected to CPF exposure. Notably, the increased levels of TLR4/TRIF signaling, RIPK/MLKL signaling, necroptosis and pro-inflammatory cytokines induced by CPF treatment were remarkably inhibited by TAK-242 (a specific TLR4 inhibitor). Additionally, the necroptosis and pro-inflammatory cytokines production induced by CPF treatment were significantly relieved by Nec-1 (a specific RIPK1 inhibitor). In general, the above results suggested that activated microglia in hippocampus subjected to developmental CPF exposure underwent RIPK1/MLKL-mediated necroptosis regulated by TLR4/TRIF signaling.

Chemicals such as triclosan are a concern because of their presence on daily products (soap, deodorant, hand sanitizers …), consequently this compound has an ubiquitous presence in the environment. Little is known about the effect of this bactericide on aquatic life. The aim of this study is to analyze triclosan exposure (24 h) to an in vitro model, zebrafish hepatocytes cell line (ZF-L), if it can be cytotoxic (mitochondrial activity, membrane stability and apoptosis) and if can activate ATP-binding cassette (ABC) proteins (activity, expression and protein/compound affinity). Triclosan was cytotoxic to hepatocytes when exposed to concentrations (1–4 mg/L). The results showed impaired mitochondria function, as well, plasma membrane rupture and an increase of apoptotic cells. We observed an ABC proteins activity inhibition in cells exposed to 0.5 and 1 mg/L. When ABCBs and ABCC2 proteins expression were analyzed, there was an increase of protein expression in both ABC proteins families on cells exposed to 1 mg/L of triclosan. On molecular docking results, triclosan and the fluorescent used as substrate (rhodamine) presented high affinity with all ABC proteins family tested, showing a greater affinity with ABCC2. In conclusion, this study showed that triclosan can be cytotoxic to ZF-L. Molecular docking indicated high affinity between triclosan and the tested pumps.

The immune organs, like thymus, are one of the targets of hydrogen sulfide (H₂S). Previously we reported that H₂S induced the differential expression of mRNAs that implicating apoptosis in thymus, however, the roles of noncoding RNAs (ncRNAs) in H₂S-induced thymus injury are still unknown. Pollution gases could alter the expression of ncRNAs, which have been shown to play important roles in many physiological and pathophysiological processes, including immune activity. This study revealed that H₂S exposure induced 9 differentially expressed circRNAs and 15 differentially expressed miRNAs in chicken thymus. Furthermore, the circRNA - miRNA - mRNA network was constructed. We discovered that circR-PTPN23 - miR-15a - E2F3 was involved in the cell cycle and apoptosis. Further, an in vitro H₂S exposure model was established using HD11 cell line and demonstrated that H₂S suppressed cell proliferation and induced apoptosis. Moreover, ciR-PTPN23 and E2F3 were downregulated, but miR-15a was upregulated in both the thymus and HD11 cell line after H₂S exposure. Bioinformatics analysis revealed that ciR-PTPN23 directly bound to miR-15a and that E2F3 was the target gene of miR-15a. Knocking down ciR-PTPN23 suppressed HD11 proliferation and caused G1 arrest and apoptosis, however, this phenomenon could be partially reversed by ciR-PTPN23 overexpression or miR-15a silencing. In summary, the ciR-PTPN23 - miR-15a - E2F3 axis was involved in H₂S-induced cell proliferation suppression and apoptosis.

The hexafluoropropylene-oxide-dimer-acid (GenX) is a short-chain perfluoroalkyl substance that was recently introduced following the phase out of PFOA, as an alternative for the process of polymerization. GenX was detected at high concentrations in rivers, drinking water and in sera of exposed workers and recent findings suggested its potential dangerousness for human health.Aim of the study was to assess the consequences of GenX exposure on in vitro thyroid cells with particular attention to the effects on cell-viability, proliferation, DNA-damage and in the thyroid-related genes expression.FRTL-5 rat-thyroid cell line were incubated with increasing concentrations of GenX for 24 h, 48 h and 72 h to assess cell viability by WST-1. DNA-damage was assessed by comet assay and further confirmed by micronucleus assay. The proliferation of survived cells was measured by staining with crystal violet and evaluation of its optical density after incubation with SDS. Changes in TTF-1, Pax8, Tg, TSH-R, NIS and TPO genes expression were evaluated by RT-PCR.GenX exposure reduced FRTL-5 viability in a time and dose-dependent manner (24 h: ANOVA F = 22.286; p < 0.001; 48 h: F = 43.253, p < 0.001; 72 h: F = 49.708, p < 0.001). Moreover, GenX exerted a genotoxic effect, as assessed by comet assay (significant increase in tail-length, olive-tail-moment and percentage of tail-DNA) and micronucleus assay, both at cytotoxic and non-cytotoxic concentrations. Exposure to GenX at concentrations non-cytotoxic exerted a significant lowering of the expression of the regulatory gene TTF-1 (p < 0.05 versus untreated) and higher expression of Pax-8 (p < 0.05 versus untreated) and a down-regulation of NIS (p < 0.05 versus untreated). In addition, cells survived to GenX exposure showed a reduced re-proliferation ability (24 h: ANOVA F = 11,941; p < 0,001; 48 h: F = 93.11; p < 0.001; 72 h F = 21.65; p < 0.001).The exposure to GenX produces several toxic effects on thyroid cells in vitro. GenX is able to promote DNA-damage and to affect the expression of thyroid transcription-factor genes.

Epidemiological relationships between pesticide use and male infertility have been suggested for a long time. Etoxazole (ETX), an oxazoline pesticide, has been extensively used for pest eradication. It is considered relatively safe and has low mammalian toxicity because it specifically inhibits chitin synthesis. However, ETX may have toxic effects on the reproductive system. In this study, we examined the effects of ETX on the reproductive system using mouse testis cell lines (TM3 for Leydig cells and TM4 for Sertoli cells) and C57BL/6 male mice. We confirmed that ETX has anti-proliferative effects on the TM3 and TM4 cell lines. Moreover, ETX induced mitochondrial dysfunction and hampers calcium homeostasis. Western blot analysis of MAPK and Akt signaling cascades was performed to demonstrate the mode of action of ETX at a molecular level. Moreover, ETX induced misregulation of genes related to testicular function. Upon oral administration of ETX in C57BL/6 male mice, testis weight was reduced and transcriptional expression related to testis function was altered. These results indicate that ETX induces testicular toxicity by inducing mitochondrial dysfunction and calcium imbalance and regulating gene expression.

This study was designed to evaluate the sensitivities of diverse cell lines on DNA damage effects and genotoxic effects of three brominated flame retardants (BFRs) and three metal ions (Cu²⁺, Cd²⁺, Hg²⁺) by comet assay. First, THP-1 was identified as the most sensitive cell line in terms of DNA damage among 11 kinds of cells screened. Accordingly, the THP-1 cell line was used as a model in subsequent single/combined genotoxicity tests. Single exposure tests to BFRs or metal ions revealed that the DNA damage effects increased with increasing exposure concentration. In combined exposure tests, BFRs (at concentrations of 1/2 EC₅₀) were deployed in combination with different concentrations of Cu²⁺, Cd²⁺, or Hg²⁺. The results showed that the % tail DNA values were significantly increased by most mixtures. Our findings on combined toxic effects by comet assay provide valuable information for setting valid environmental safety evaluation standards.

Microplastics (MPs), are tiny plastic fragments from 1 μm to 5 mm generally found in the aquatic environment which can be easily ingested by organisms and may cause chronic physical but also toxicological effects. Toxicological assays on fish cell lines are commonly used as an alternative tool to provide fast and reliable assessment of the toxic and ecotoxic properties of chemicals or mixtures. Rainbow trout liver cell line (RTLW-1) was used to evaluate the toxicity of pollutants sorbed to MPs sampled in sandy beaches from different islands around the world during the first Race for Water Odyssey in 2015. The collected MPs were analyzed for polymer composition and associated persistent organic pollutants: polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT). In addition, DMSO-extracts from virgin MPs, MPs artificially coated with B[a]P and environmental MPs were analyzed with different bioassays: MTT reduction assay (MTT), ethoxyresorufin-O-deethylase (EROD) assay and comet assay. Microplastics from sand beaches were dominated by polyethylene, followed by polypropylene fragments with variable proportions. Organic pollutants found on plastic from beach sampling was PAHs (2–71 ng g⁻¹). Samples from Bermuda (Somerset Long Bay) and Hawaii (Makapu'u) showed the highest concentration of PAHs and DDT respectively. No toxicity was observed for virgin microplastics. No cytotoxicity was observed on cells exposed to MP extract. However, EROD activity was induced and differently modulated depending on the MPs locations suggesting presence of different pollutants or additives in extract. DNA damage was observed after exposure to four microplastics samples on the six tested. Modification of EROD activity level and DNA damage rate highlight MPs extract toxicity on fish cell line.

Di-(2-ethylhexyl) phthalate (DEHP) is used extensively in many personal care and consumer products, resulting in widespread non-occupational human exposure through multiple routes and media. DEHP has various deleterious effects including hepatotoxicity. p53 protein is a central sensor in cell apoptosis. In order to clarify the roles of p53 in DEHP-induced hepatotoxicity, Sprague–Dawley (SD) rats were dosed daily with DEHP by gavage for 30 days; BRL cells (rat liver cell line) were treated with DEHP for 24 h after pretreatment with NAC or small interfering RNA (siRNA). Results indicated that after exposure to DEHP, hepatic histological changes such as hepatocyte edema, vacuolation and hepatic sinusoidal dilation, and increased apoptosis index were observed. In the liver, DEHP induced oxidative stress and DNA damage, which activated p53 in vivo and in vitro. Pretreatment with NAC significantly reduced ROS level and p53 expression in BRL cells. The suppressed Mdm2 also contributed to p53 accumulation. Activated p53 mediated hepatocyte apoptosis via the intrinsic mitochondrial pathway, inhibiting anti-apoptotic Bcl-2 and Bcl-xL and inducing pro-apoptotic Bax, cytochrome c and caspases. In p53-silenced BRL cells, hepatocyte apoptosis mediated by p53 was attenuated. PCNA protein level was upregulated after p53 gene silencing. However, the Fas/FasL apoptotic pathway did not exhibit activated signs in DEHP-caused hepatotoxicity. Taken together, DEHP-caused oxidative stress and Mdm2 downregulation contribute to p53 activation. The p53-dependent apoptotic pathway plays critical and indispensable roles in DEHP-induced hepatotoxicity, while the Fas/FasL pathway does not involve in this molecular event.

Currently, urbanization is associated with an increase in air pollutants that contribute to invasive pathogen infections by altering the host's innate immunity and antimicrobial resistance capability. Streptococcus pyogenes, also known as Group A Streptococcus (GAS), is a gram-positive opportunistic pathogen that causes a wide range of diseases, especially in children and immunosuppressed individuals. Diesel exhaust particle (DEP), a significant constituent of particulate matter (PM), are considered a prominent risk factor for respiratory illness and circulatory diseases worldwide. Several clinical and epidemiological studies have identified a close association between PM and the prevalence of viral and bacterial infections. This study investigated the role of DEP exposure in increasing pulmonary and blood bacterial counts and mortality during GAS M1 strain infection in mice. Thus, we characterized the upregulation of reactive oxygen species production and disruption of tight junctions in the A549 lung epithelial cell line due to DEP exposure, leading to the upregulation of GAS adhesion and invasion. Furthermore, DEP exposure altered the leukocyte components of infiltrated cells in bronchoalveolar lavage fluid, as determined by Diff-Quik staining. The results highlighted the DEP-related macrophage dysfunction, neutrophil impairment, and imbalance in pro-inflammatory cytokine production via the toll-like receptor 4/mitogen-activated protein kinase signaling axis. Notably, the tolerance of the GAS biofilms toward potent antibiotics and bacterial resistance against environmental stresses was also significantly enhanced by DEP. This study aimed to provide a better understanding of the physiological and molecular interactions between exposure to invasive air pollutants and susceptibility to invasive GAS infections.

Exposure to electronic and electrical waste (e-waste) has been related to a few adverse health effects. In this study, sediment samples from an e-waste recycling town in China were collected, and aryl hydrocarbon receptor (AhR) agonists in the samples were identified using an effect-directed analysis (EDA) strategy. The CBG2.8D cell line reporter gene bioassay was used as a toxicity test, while suspect screening against chemical databases was performed for potential AhR agonist identification where both gas chromatography- and liquid chromatography-high resolution mass spectrometry analyses were run. When the original sample extract showed high AhR-mediated activity, sample fractionation was performed, and fractions exhibiting high bioactivity were chemically analyzed again to reveal the corresponding AhR agonists. In total, 23 AhR agonists were identified, including 14 commonly known ones and 9 new ones. Benzo [k]fluoranthene and 6-nitrochrysene were the dominant AhR agonists, covering 16–71% and 2.7–12%, respectively, of the AhR activation effects measured in the parent extracts. The newly identified AhR-active chemicals combined explained 0.13–0.20% of the parent extracts’ effects, with 7,12-dimethylbenz [a]anthracene and 8,9,11-trimethylbenz [a]anthracene being the major contributors. A diagnostic isomer ratio analysis of polycyclic aromatic hydrocarbons suggested that the major source of AhR agonists identified in these e-waste related sediment samples were probably petroleum product combustion and biomass combustion. In the future, for a more comprehensive AhR agonist investigation, in-house chemical synthesis and purification, and, when necessary, a secondary sample fractionation, would be beneficial.