Methyl methacrylate (MMA) is a widely used foundational monomer in industrial and medical manufacturing. Current occupational exposure limits (OELs) for MMA are established based on its irritant and sensitizing effects, which may not fully prevent its genotoxicity. Here, we conducted an occupational biomonitoring study, including 45 MMA-exposed workers, 26 MMA-toluene/xylene-exposed (MMA-TX) workers, and 31 concurrent controls from a machinery manufacturing plant. Genetic damage in peripheral blood was assessed using the novel PIG-A mutation assay and cytokinesis-block micronucleus test. MMA-exposed workers showed significantly higher PIG-A mutant frequencies (10.49 ± 7.84 vs. 5.00 ± 2.70 × 10−6), and frequencies of micronuclei (6.28 ± 2.97 vs. 3.40 ± 1.67‰), nucleoplasmic bridges (0.80 ± 0.67 vs. 0.32 ± 0.49‰), and nuclear buds (1.68 ± 1.02 vs. 0.48 ± 0.58‰) than the controls. MMA-TX-exposed workers had significantly higher PIG-A mutant frequencies (15.15 ± 11.37 × 10−6) than MMA-exposed workers, and exhibited a slightly higher but non-significant biological age acceleration, as estimated using the Klemera–Doubal method from clinical biomarkers. Quantitative benchmark dose analysis yielded a point of departure of 0.03 mg/m3-year for MMA-induced genetic damage, indicating a lower exposure threshold than the current OELs. In MMA-treated TK6 cells, a slight increase in C > T mutations was observed using high-accuracy error-corrected sequencing, resembling the mutational signature of formaldehyde, a metabolite of MMA. The findings demonstrate that MMA below the current OELs may induce cumulative genetic damage in MMA-exposed workers, providing a quantitative basis for revising OELs to better protect worker health.
Advanced maternal age is a well-established risk factor for adverse reproductive outcomes due to increased rates of aneuploidy. However, emerging evidence indicates that the genetic consequences of maternal aging extend well beyond chromosome mis-segregation. Aging oocytes acquire a broad spectrum of genetic abnormalities, including maternally derived nuclear de novo mutations (DNMs) and mitochondrial DNA mutations, together with epigenetic dysregulation of DNA methylation and post-translational modification levels. These changes reflect the unique biology of the female germline in which oocytes remain arrested in meiotic prophase I for decades. Age-related deterioration of key processes, such as erosion of cohesion complexes, altered meiotic recombination, and weakened spindle assembly checkpoint surveillance collectively destabilize meiotic chromosome architecture, directly driving chromosome mis-segregation. At the same time, accumulation of endogenous DNA damage and declining DNA damage and repair processes increase the chances of transmitting lesions that can be converted into sequence-level mutations during the earliest embryonic divisions, when genome maintenance relies exclusively on maternal factors. High-resolution sequencing studies further demonstrate that maternal aging is associated with increased DNMs burden in both nuclear and mitochondrial DNA. Together, these findings support a model in which maternal aging is a driver of genome-wide instability that links aneuploidy and mutagenesis through shared defects in meiotic surveillance, declining DNA repair efficiency, and mitochondrial function. This framework positions delayed childbearing as a multifaceted genetic risk factor that extend beyond aneuploidy to include mutations and other genomic alterations that can impact intergenerational genetic risk.
Kashin-Beck disease (KBD) is a multifactorial endemic osteoarthropathy that has been associated with nutritional and environmental factors, including selenium deficiency and T-2 toxin exposure. However, whether combined selenium deficiency and T-2 toxin exposure affects hepatic xenobiotic metabolism has not been systematically investigated. Male C57BL/6 mice were fed a selenium-adequate or selenium-deficient diet for 4 weeks, followed by another 4 weeks with or without daily oral T-2 toxin (0.2 mg/kg). Plasma selenium and glutathione peroxidase (GPx) activity were measured. Hepatic histology, activities of major mouse cytochrome P450 (Cyp450) isoforms, and corresponding mRNA and protein expression were assessed. RNA sequencing was performed using liver samples from four biological replicates per group to identify differentially expressed genes (DEGs) and enriched pathways. Selenium deficiency was confirmed by significantly reduced plasma selenium levels and GPx activity. Histological examination revealed marked hepatic steatosis. Transmission electron microscopy further showed prominent ultrastructural alterations including endoplasmic reticulum dilation. The activities of five hepatic Cyp450 isoforms, Cyp1a2, Cyp2b10, Cyp2c29, Cyp2c50, and Cyp3a11, were significantly increased to 1.64–2.51 times the control levels, consistent with increased mRNA and protein expression. Combined selenium deficiency and T-2 toxin exposure was associated with increased hepatic Cyp450 enzyme activity and expression, identifying the liver as a responsive target of KBD-related exposures. These findings suggest the need to further evaluate hepatic xenobiotic metabolism in populations from KBD-endemic areas.
Chronic exposure to pesticide mixtures through diet is common, yet their combined metabolic effects and interactions with dietary factors remain unclear. We identified four pesticides prevalent in human exposure (imazalil, thiabendazole, boscalid, lambda-cyhalothrin) and assessed their combined impacts on hepatic metabolism and metabolic homeostasis using human liver cells and male mice fed standard chow or western diets. We found that the pesticide mixture induced metabolic perturbations in human hepatocytes. In addition, the pesticide mixture altered hepatic gene expression in chow-fed mice and exacerbated western diet-induced glucose intolerance, fasting hyperglycemia, and insulin resistance without affecting body weight or liver steatosis. These findings reveal that dietary context influences the metabolic consequences of pesticide mixtures, highlighting the need to consider nutritional status when evaluating environmental contaminant risks. Our results suggest that pesticide mixtures at reference doses may contribute to metabolic dysregulation, particularly under obesogenic dietary conditions. Four common pesticides in mixture disrupt metabolism in liver cells. Dietary exposure to this pesticide mixture alters hepatic gene expression in mice. The pesticide mixture exacerbates WD-induced disruptions in glucose homeostasis. Pesticides and diet interact in producing the metabolic effects of a pesticide mixture.
Beauvericin (BEA) and enniatins (ENNs) are Fusarium mycotoxins found in cereals and cereal-based foods as reported in several studies. But information on human internal exposure remains scattered. Human biomonitoring (HBM) enables the investigation of exposure to these nonregulated contaminants. This review summarizes data from studies published since 2014 on occurrence of BEA and ENNs in human urine, blood, breast milk, tissues and hair. Most studies from Europe, Africa, Asia and North America applied state-of-art methodologies for biomarker analysis. ENN B was the most frequently detected compound and was found in a high proportion of blood samples across different populations. Although BEA was reported less frequently, measurable levels were found in plasma, breast milk, tissues and, more recently, in urine. Both BEA and ENNs were found in human milk, indicating transfer from mother to infant, but generally at low concentrations. Data for human tissues suggest differences in distribution, with BEA occurring mainly in adipose tissue and ENN B reaching the highest concentrations in liver. Some studies reported phase-I metabolites of ENNs in urine, demonstrating that biotransformation contributes to their elimination in humans. Available HBM data indicate widespread dietary exposure to BEA and ENNs in several human populations. Concentrations measured in blood and tissues are much lower than those associated with their cytotoxic effects in vitro. Uncertainties remain regarding human toxicokinetics and the toxicological relevance of their metabolites. Further studies addressing these gaps will improve interpretation of biomonitoring data and support the human health risk assessment of these emerging mycotoxins.
Micro- and nanoplastics (MPs/NPs) are ubiquitous anthropogenic particulate pollutants posing emerging threats to human neurological health. Severe heterogeneity in particle physicochemical properties, environmental aging status, exposure paradigms and experimental platforms has created persistent mechanistic uncertainties in MP/NP neurotoxicology, hindering reliable hazard characterization and risk translation. Here, we systematically consolidate empirical toxicological evidence and construct a dedicated central nervous system (CNS)-targeted adverse outcome pathway (AOP) network integrated with rigorous weight-of-evidence (WoE) grading to elucidate the hierarchical, particle-specific toxic cascades underlying MP/NP-induced neural injury. Our synthesis overturns the conventional linear toxicity paradigm, demonstrating that MPs/NPs trigger neurotoxicity via a complex multi-input mechanistic network. We definitively establish oxidative stress as a robust early convergent key event—rather than a universal molecular initiating event—orchestrating ROS overproduction, lipid peroxidation, mitochondrial dysfunction, and neuroinflammation to propagate neuronal damage. This core module is driven by five distinct particulate upstream triggers: particle–biomolecule interfacial perturbation, corona-facilitated cellular internalization, plastic-associated chemical leaching, aging-derived free radical reactivity, and gut-borne systemic neurotoxic signaling. Downstream pathogenic outcomes encompass glial overactivation, neurotransmitter dyshomeostasis, autophagy–lysosome dysfunction, metabolic reprogramming, regulated neuronal cell death, and behavioral impairments. Tiered WoE analysis confirms strong validation for early oxidative/inflammatory cascades, moderate support for gut–brain axis crosstalk and intracellular trafficking disruption, and nascent evidence for synaptic dysfunction and neurodegeneration-linked proteostatic defects. Extrapolation to human health risk remains constrained by the frequent use of high-dose exposure paradigms, limited validated data on internal dosimetry in the human brain, discrepancies between effective concentrations in experimental models and environmentally relevant human tissue burdens, and insufficient causal validation of distal adverse outcomes. We highlight key research priorities including aged mixed-particle exposure systems, leachate-controlled assays, quantitative internal dose evaluation, and mechanistic intervention verification. This evidence-stratified AOP framework resolves longstanding mechanistic ambiguities in particulate neurotoxicity, providing a standardized, causality-based foundation for future mechanistic exploration and health risk assessment of global plastic pollution.
Deoxynivalenol (DON) and its derivatives are widely distributed contaminants that seriously threaten food security and animal husbandry production. Biodegradation has become a core research direction for detoxification owing to its high efficiency and specificity. Although numerous studies have reported the toxicity, metabolism and degradation of DON and its derivatives, systematic reviews that integrate toxic mechanisms, species differences, degrading strains and key enzymes remain scarce. This paper comprehensively reviews the toxicological mechanisms and toxicokinetic characteristics of DON and its typical derivatives, and illustrates the physiological basis for species sensitivity differences. It mainly summarizes various degrading bacteria, fungi and core enzymatic catalytic pathways, and analyzes the potential risks of masked mycotoxins as well as the application bottlenecks of current biological detoxification technologies. Future research directions are also prospected. This review can serve as a reference for the research, development and industrial application of efficient and safe microbial detoxification strategies.
Flavoured-air inhalers containing essential oils are marketed as safe, natural alternatives to smoking and vaping, yet their potential respiratory toxicity remains effectively unexamined. Manufacturers claim safety based on "100
Drug-induced cardiotoxicity, mainly driven by cardiac ion-channel blockade, remains a leading cause of drug attrition and post-market withdrawal, highlighting the need for reliable early-stage screening tools. Existing computational methods, including QSAR models, largely focus on single ion channels, limiting their ability to assess multi-channel safety profiles. To address this gap, we developed Cardiosim-Tox, a modular multi-modal deep learning platform to simultaneously predicts blockade risk (binary classification) and potency (pIC50) for hERG, Cav1.2, and Nav1.5. The framework integrates topological fingerprints, Mordred 2D/3D descriptors, and molecular graph encodings under both single-task (STL) and multi-task learning (MTL) configurations. Developed on 31,816 curated unique compounds, model performance was evaluated on three Tanimoto similarity-stratified external validation sets, with domain-shift metrics and applicability domain analyses supporting robustness. MTL models consistently outperformed STL, while the full modality combination (FP + MD + Graph) achieved AUCs of 0.93–0.98 for Cav1.2, 0.88–0.96 for Nav1.5, and 0.79–0.95 for hERG across validation sets. Regression tasks similarly favored MTL (R2 = 0.94), with multimodal configurations outperforming single-modality baselines. Further comparisons with classical machine learning models and previously developed cardiotoxicity models demonstrated the superiority of Cardiosim-Tox across all endpoints. SHAP analysis confirmed that feature–activity relationships, both at global and mechanistic levels, align with known ion-channel pharmacophores, enhancing interpretability beyond predictive accuracy. Overall, Cardiosim-Tox provides a reliable and interpretable platform for integrated multi-channel cardiac safety assessment, supporting early-stage cardiotoxicity screening in drug development in line with the CiPA paradigm. The Cardiosim-Tox web server is accessible at https://metaheart.kr/login .
Cytochrome P450 2E1 (CYP2E1) plays a pivotal role in the metabolism and detoxification of low molecular-weight xenobiotics, as well as in their bioactivation into toxic and DNA-reactive intermediates. Prominent examples include drugs and chemicals like acetaminophen and N-nitrosamines. Chlorzoxazone and 4-nitrophenol are widely used as probe substrates to assess CYP2E1 activity, however, their specificity remains controversial. This study aimed to reevaluate the selectivity of chlorzoxazone and 4-nitrophenol toward CYP2E1 using recombinant Supersomes™ expressing individual human CYP isoforms. Incubations were performed with chlorzoxazone and 4-nitrophenol at 100 and 500 µM, followed by quantification of 6-hydroxychlorzoxazone and 4-nitrocatechol via UPLC-MS/MS. Chlorzoxazone turnover was detected across nearly all major liver CYP isoforms, with CYP1A1 showing the highest contribution (39%), followed by CYP2D6 (14%), CYP1A2 (10%), and CYP2E1 (10%). Similarly, 4-nitrophenol hydroxylation was not limited to CYP2E1, with significant contributions from CYP1A2 (20%), CYP2A6 (19%), and CYP2D6 (16%), while CYP2E1 accounted for 26% of total activity. In conclusion, our results underscore the limited selectivity of chlorzoxazone and 4-nitrophenol and highlight the need for more specific substrates for accurate CYP2E1 enzyme characterization.
High-throughput screening data have become the de facto ground truth for in silico toxicology. But a high-throughput “active” can reflect target engagement, non-specific cytotoxicity, or assay interference and the programmes that generate these data flag the latter two with dedicated counter-screens. When models are trained on the hit-calls without those flags, they can learn how the assay behaved rather than how the chemical harms. Because the confounders are structurally systematic, they are exactly the kind of signal a structure-based model will capture. This Commentary sets out the problem and four low-cost controls.
Metabolic dysfunction–associated steatotic liver disease (MASLD) represents a growing global health concern; however, its multiple pathogenic mechanisms remain incompletely understood. The role of the aryl hydrocarbon receptor (AHR) in MASLD is controversial, as it has been described as either pro- or anti-steatotic depending on the experimental context. Through whole-genome expression profiling and RT-qPCR analysis of human liver biopsies from two independent MASLD patient cohorts, we demonstrate that AHR expression and its canonical activity—assessed by CYP1A1 mRNA levels—are inversely correlated with hepatic steatosis. The role of AHR was further investigated in cultured human Upcyte® hepatocytes from different donors treated with a 2:1 oleate:palmitate mixture (0.6 mM) to induce steatosis, in combination with the exogenous AHR agonist β-naphthoflavone (BN, 25 µM) or the endogenous agonist 2-(1′H-indole-3′-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE, 25 µM). Activation of AHR resulted in a statistically significant reduction of intracellular lipid levels, as determined by triglyceride quantification and AdipoRed staining. Microarray analysis of AHR-activated human hepatocytes identified IGFBP1 as a robustly induced target gene. Consistently, IGFBP1 expression was diminished in the livers of both MASLD cohorts and positively correlated with AHR expression levels. Furthermore, treatment of human hepatocytes with recombinant IGFBP1, alone or in combination with IGF1, reduced lipid accumulation, supporting IGFBP1 as a potential downstream effector within the anti-steatotic AHR pathway. Collectively, these findings support a role for AHR and its target IGFBP1, as key negative regulators of hepatic lipid accumulation in human hepatocytes and suggest that activation of this pathway may be taken into account in the therapeutic approaches for MASLD.
The structural diversity and continuous emergence of synthetic cannabinoid receptor agonists (SCRAs) pose an important challenge to forensic and clinical toxicology. Understanding their metabolic pathways is essential for identifying reliable consumption biomarkers and improving toxicological screening strategies. This pilot study has investigated the influence of chemical structure on the metabolism of eight structurally diverse SCRAs: AMB-FUBINACA, ADB-FUBINACA, SDB-005, APINACA, CUMYL-4CN-BINACA, 5 F-AMB-PINACA, 5 F-AB-PINACA, and THJ-2201. The compounds were administered to male Sprague-Dawley rats from which serum and urine samples were analysed using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS). Metabolite identification was achieved through different analytical strategies. Following structural elucidation, the in vivo metabolism for each SCRA was evaluated, and the corresponding metabolic pathways were proposed. A comparative analysis of the different metabolic reactions was subsequently performed, classifying biotransformations according to the site of occurrence within the molecule, to highlight both shared features and compound-specific pathways. The results demonstrated significant variability in the number and type of metabolites identified, underscoring the substantial influence of chemical structure on SCRA metabolism. Despite this variability, consistent biotransformations across compounds were also observed. Notably, this in vivo study allowed the detection of several metabolites not previously reported in in vitro models, demonstrating the added value of in vivo approaches in profiling the complete metabolic fate of SCRAs.
The uterotrophic bioassay is a recognized tool for assessing estrogenic activities of chemicals, relying on estrogen-induced uterine growth. This study employed the assay in immature female rats using ethinyl estradiol (EE) to explore temporal gene expression dynamics in the uterus and pituitary gland, both estrogen-responsive organs. Gene expression changes were evident as early as 2 h post-EE administration in the uterus, with early responses indicating increased proliferation, macromolecule synthesis, and immune responses—notably through WNT/β-catenin signaling and cholesterol biosynthesis. Estrogen’s influence on inflammation was observed, with macrophage polarization shifting from anti-inflammatory M2 to pro-inflammatory M1 types over time. In the pituitary gland, early gene upregulation suggested proliferative and metabolic responses to estrogen. The findings enhance understanding of estrogen’s effects on uterine and pituitary function during the uterotrophic assay, offering avenues for assay optimization, improved in vitro models, and refined adverse outcome pathways (AOPs).
