Archives of Toxicology

Alternaria toxins are naturally occurring food contaminants with limited and often inconsistent genotoxicity and mutagenicity data. Within the European Partnership for the Assessment of Risks from Chemicals (PARC), an OECD-aligned in vitro testing strategy was applied to fill existing data gaps and to characterize the genotoxic potential of major Alternaria toxins using high-purity test materials. Mutagenicity was assessed using bacterial reverse mutation test (OECD TG 471) and SOS/umu assay, while chromosomal damage was assessed using the in vitro micronucleus (MN) assay (OECD TG 487) in TK6 and HepG2 cells, complemented by fluorescence in situ hybridization (FISH) and {gamma}H2AX assay in HepaRG cells. Alternariol (AOH), alternariol monomethyl ether (AME), and altertoxin-I (ATX-I) showed clear mutagenicity in bacteria, whereas altenuene (ALT), tenuazonic acid (TeA), and tentoxin (TEN) were negative under the tested conditions. In mammalian cells, AOH, AME, and ATX-I induced MN formation in TK6 cells at concentrations [≥]5.5 {micro}M, [≥]2.5 {micro}M, and [≥]0.21 {micro}M, respectively, with FISH analysis supporting a clastogenic mode of action. In HepG2 cells, all tested toxins induced chromosomal damage, with effect threshold ranging from [≥]6.25 {micro}M (AOH) to [≥]50 {micro}M (TeA). {gamma}H2AX induction confirmed DNA damage for AOH and ATX-I, and at higher concentrations for TeA (1000 {micro}M). Overall, the data indicate clear in vitro genotoxic potential for AOH, AME, and ATX-I and provide evidence of chromosomal damage for ALT, TEN, and TeA, thereby reducing critical data gaps for hazard assessment.

The foodborne mycotoxins alternariol (AOH) and alternariol monomethyl ether (AME) have been associated with several adverse effects, including cytotoxicity, genotoxicity, endocrine disruption, and immunomodulation. As these endpoints are typically observed in vitro at micromolar concentrations, the question arises whether such levels are attainable in exposed humans. To address this data gap in chemical risk assessment, a physiologically based kinetic (PBK) model was developed to predict internal exposure doses to AOH and AME in humans. As input parameters, kinetic constants for hepatic glucuronidation were obtained in vitro by incubating Sprague Dawley rat and human liver S9 fractions with 0.5-50 M AOH and 0.5-20 M AME, demonstrating rapid biotransformation in both species. Intestinal absorption of AME and physicochemical parameters were estimated using quantitative structure-activity relationship (QSAR) models. Sensitivity analysis identified parameters describing hepatic glucuronidation and gastrointestinal uptake as among the most influential, confirming the importance of their reliable estimation. The PBK model was evaluated against available rodent toxicokinetic data and subsequently extrapolated to humans. Ultimately, the currently available exposure estimates published by EFSA in 2016 were applied to predict target tissue concentrations, which were compared to points of departure (PoDs) for relevant toxicological endpoints. Even in the most susceptible group of male toddlers, predicted internal concentrations (10-4 M range) were approximately four orders of magnitude below the respective PoDs. Consequently, under the applied exposure assumptions and considering the compounds as isolated chemicals, AOH and AME are not expected to reach systemic or tissue concentrations associated with the investigated effects.

Cytochrome P450 (CYP)-mediated biotransformation of endogenous and xenobiotic substances can lead to altered exposure, toxicological impact, or adverse drug reactions. CYP induction data are fundamental to regulatory chemical toxicity hazard assessment because they directly affect the in vivo fate of xenobiotics, potentially influencing their safety and efficacy of pharmaceuticals, and impacting the safety assessment of industrial chemicals, and environmental contaminants. Here we report on the third laboratory supplementary validation of an established and previously validated human HepaRGTM in vitro method able to detect CYP1A2, CYP2B6, and CYP3A4 induction, to support the expansion of the chemical applicability domain beyond pharmaceuticals. This study was conducted to support the part 1 study with additional robust data. We established the test method in-house using the 10 previously validated pharmaceutical proficiency chemicals, then tested a further 6 proposed augmentation chemicals, tebuconazole, benfuracarb, chlorpyrifos, N, N-Diethyl-meta-toluamide, fipronil, permethrin, as tested in part 1, and then four additional chemicals: prochloraz, atrazine, pyrimethanil, and chlorpyrifos-methyl. LC-MS/MS was utilised to measure the conversion of a cocktail mixture of prototypical selective CYP probe substrates to their metabolites, in parallel with mRNA measurements. We achieved high concordance with expected classifications for proficiency and additional chemicals. Comparisons with mRNA-based measurements suggested gene expression may serve as a cost-effective pre-screening tool for CYP1A2 and CYP3A4, though with greater uncertainty for CYP2B6. The data support the robustness of the HepaRG method for CYP induction testing and the adoption of the test method in 2026 as an Organisation for Economic Cooperation and Development Test Guideline. Plain language summaryCytochrome P450 (CYP) enzymes metabolize drugs, pesticides, and other chemicals. Chemicals that increase or decrease CYP enzyme activity can change internal exposure levels, potentially leading to unexpected toxicity or impact drug effectiveness. Reliable in vitro methods to assess CYP induction are needed for regulatory chemical safety assessment. This study describes results from a third laboratory applying a previously validated human HepaRG cell-based method to assess induction of CYP1A2, CYP2B6, and CYP3A4. After successful in-house implementation using ten reference pharmaceutical compounds, the method was extended to ten more industrial chemicals. CYP induction was evaluated by measuring enzyme activity and changes in gene expression. The test method showed a high level of agreement with expected induction outcomes. Gene expression data supported enzyme activity results, particularly for CYP1A2 and CYP3A4. These results strengthen confidence in the robustness and wider applicability of the method for Organisation for Economic Cooperation and Development Test Guideline adoption.

The ubiquitously occurring food contaminants altenuene (ALT) and tentoxin (TEN) are recognized as emerging Alternaria mycotoxins, yet substantial data gaps remain when it comes to their toxicological behavior and toxicokinetic characteristics. This study aimed to compare and generate quantitative data on their hepatic metabolism and to obtain semi-quantitative insights into their metabolite profiles. To this end, primary rat and human hepatocytes were incubated with 10 {micro}M ALT or TEN over multiple time points up to 4 h. Both substrate depletion and metabolite identification revealed pronounced interspecies differences. The extent of ALT metabolism was significant, with an 88% and 57% decrease in rat and human hepatocytes after 4 h, respectively. In contrast, TEN showed extensive biotransformation in rats (67%) but only modest turnover in humans (27%) over the same period. Hepatocellular clearances were consistently higher for ALT than TEN, with hepatic extraction ratios indicating intermediate extraction for ALT and low extraction for TEN. High-resolution mass spectrometry combined with targeted analysis of selected metabolites annotated phase II conjugation as the predominant metabolic pathway for ALT and phase I oxidative metabolism for TEN, including mono- and double-metabolized species for the latter. Overall, these results provide a comprehensive characterization of ALT- and TEN-metabolism in hepatocytes, offering a foundation for future studies on their toxicological relevance and impact on human health.

Cytochrome P450 (CYP) enzymes play a key role in the metabolism of both xenobiotics and endogenous compounds, and the activity of some CYP isoforms are susceptible to induction and/or inhibition by certain chemicals. As CYP induction and inhibition can significantly alter the in vivo fate of xenobiotics i.e., levels of parent chemicals and/or metabolites, and thus toxicity, CYP induction/inhibition data is needed for regulatory chemical toxicity hazard assessment. Utilizing available human in vivo pharmaceutical data, a successful validation was previously conducted on the in vitro HepaRG CYP induction test method for measurement of induction of three key human CYP enzymes CYP1A1/1A2, 2B6 and 3A4. However, further validation data was required to demonstrate applicability of the test method to also accurately detect CYP induction mediated by industrial and pesticidal chemicals. Here we report on the supplementary validation of the HepaRG CYP enzyme induction test method carried out in two laboratories under the auspices of the EU Horizon2020-funded project "GOLIATH", to expand the chemical applicability domain beyond pharmaceutical chemicals. Successful transfer was demonstrated and reproducibility assessed for the original 10 selected proficiency pharmaceuticals, plus three reference inducers together with six additional non-pharmaceutical augmentation chemicals. The method and chemical selection were found to be reliable and relevant for the routine assessment of human CYP induction. For the augmentation chemicals being proposed as additional proficiency chemicals, the test method achieved a reasonable but not optimum reproducibility. Recommendations are proposed to improve the test methods specificity, reflecting the inherent uncertainty around borderline CYP inducing chemicals. Plain language summaryCytochrome P450 (CYP) enzymes help break down drugs and other chemicals in the body. Their activity can be increased (induced) or decreased (inhibited), which can change how toxic a chemical is and when it is excreted. Because of this, CYP data is important for chemical safety assessments. A laboratory-based method using HepaRG cells was previously validated to measure induction of key CYP enzymes (CYP1A1/1A2, CYP2B6 and CYP3A4) using pharmaceutical chemicals. This study aimed to show that it also works well for industrial and pesticidal chemicals. In the EU funded GOLIATH project, two laboratories tested 10 pharmaceutical and 6 non-pharmaceutical chemicals. The method showed good reliability overall and strong reproducibility for pharmaceuticals. For non-pharmaceutical chemicals, results were acceptable but less consistent. The study concludes that the method is useful for routine testing, but improvements are needed to increase accuracy and better handle chemicals that show weak or borderline CYP induction effects.

BackgroundThe cardiovascular system is significantly affected by exogenous factors, but understanding the risks posed by pharmaceuticals and environmental chemicals is restricted due to limited data availability. New approach methodologies (NAMs) apply in vitro, in chemico, and in silico methods to characterize hazard and risk, thus offering rapid, multiscale human biology-based strategies to overcome regulatory challenges and the potential to complement or replace animal testing for understanding chemical cardiovascular effects. MethodsIn the present study, we applied a systems-based workflow using physiologically based pharmacokinetic (PBPK) models to convert bioactive concentrations from >300 high-throughput screening (HTS) assays with cardiovascular-relevant molecular and cellular targets to human equivalent administered doses (EADs) for >800 substances with widespread human exposure potential. To derive human-relevant risk predictions, the in vitro activity-derived EADs were compared with human exposure estimates and in vivo points of departure (PODs) from toxicological animal studies. For a subset of chemicals, we applied a geospatial analysis to assess the combined risks for populations across regions of the US. ResultsThe combined HTS assay data, human exposure predictions, animal study-based PODs, geospatial exposure data, and PBPK modeling identified compounds with potential cardiovascular toxicity at relevant exposure levels. Personal care product ingredients, flame retardants, herbicides, pesticides, pharmaceuticals, and byproducts of various industrial processes were noted as agents of concern preferentially targeting endothelial cell signaling, nuclear hormone receptors, and other critical cardiovascular targets. Of the 859 chemicals assessed, in vitro CV-relevant assays were more risk protective than animal studies for 96.4% of the chemicals. A set of 17 chemicals had a log10 bioactivity exposure ratio (BER) below -2, indicating estimated human exposure more than 100-fold above the in vitro-derived bioactive dose. ConclusionsThis study establishes an integrative, multiscale framework linking molecular perturbations to population-level cardiovascular risk, enabling systematic identification of potentially cardiotoxic chemicals and the communities most vulnerable to their effects. By bridging mechanistic toxicology with pharmacokinetic modeling and epidemiologic context, this approach enhances the biological relevance and translational impact of human health risk assessment. This scalable, adaptable framework supports timely, evidence-based decision-making and aligns with the growing adoption of NAMs to advance cardiovascular research and disease prevention. Novelty and SignificanceO_ST_ABSWhat is known?C_ST_ABSHigh-throughput screening (HTS) assays can identify chemicals with activity at cardiovascular (CV) relevant molecular targets, but translating in vitro bioactivity concentrations into biologically meaningful human equivalent doses requires physiologically based pharmacokinetic (PBPK) modelling. The bioactivity exposure ratio (BER) provides a data-driven metric for comparing in vitro-derived equivalent administered doses against population exposure estimates, but its application to CV endpoints across a large and chemically diverse environmental chemical landscape has not been demonstrated. Geospatial mapping of CV chemical exposure risk has been demonstrated for a limited set of air pollutants but has not been extended to a broad environmental chemical landscape using human-relevant in vitro bioactivity data. What new information does this article contribute?Integrated in vitro to in vivo extrapolation (IVIVE) across 859 environmental chemicals demonstrates that cardiovascular-relevant in vitro endpoints are sensitive indicators of broader systemic toxicity, 96.4% of chemicals showed positive POD ratios, meaning in vitro CV assays flagged hazard at lower doses than non-specific animal toxicity studies despite the absence of endpoint matching. Seventeen chemicals including PFAS, brominated flame retardants, endocrine disruptors, and agricultural herbicides, had a BER below -2, indicating estimated human exposure more than 100-fold above the in vitro-derived cardiovascular bioactive dose, with convergent evidence from both in vitro and in vivo data supporting regulatory priority. County-level geospatial mapping reveals that cardiovascular chemical exposure risk is geographically heterogeneous across the United States, concentrated in industrially active regions already associated with elevated cardiovascular disease mortality, identifying specific populations for targeted environmental monitoring. SummaryThis study presents a scalable, systems-based IVIVE framework that integrates cardiovascular-relevant in vitro HTS bioactivity data with reverse dosimetry, population exposure predictions, and in vivo animal toxicity data to prioritize environmental chemicals for cardiovascular risk assessment. Applied to 859 chemicals spanning personal care products, flame retardants, pesticides, pharmaceuticals, and industrial compounds, the framework demonstrates that CV-relevant in vitro endpoints are sensitive indicators of systemic toxicity even in the absence of direct endpoint matching with in vivo studies. The BER emerges as a flexible and resource-adaptable prioritization metric, identifying 92 chemicals where estimated human exposure falls within the CV bioactive range, of which 17 represent the highest regulatory priority based on convergent evidence from both data streams. Geospatial mapping further reveals regional heterogeneity in cardiovascular chemical exposure risk concentrated in industrial areas of the central and southeastern United States. This work advances the application of new approach methodologies for cardiovascular chemical risk assessment at a time of accelerating regulatory transition toward human-relevant in vitro-based safety evaluation, providing a reproducible computational workflow directly applicable to chemical prioritization under evolving EPA and FDA regulatory frameworks.

Acetaminophen (APAP) overdose is the leading cause of acute liver failure (ALF), with acute kidney injury (AKI) contributing substantially to morbidity and mortality in those patients. To determine whether APAP-induced AKI depends on hepatic CYP2E1-mediated bioactivation, we used CYP2E1^flox/flox^ mice treated with AAV8-TBG-Cre to selectively delete hepatic CYP2E1 while preserving renal metabolism. Male and female mice received APAP (600 mg/kg) and were evaluated up to 48 hours for liver and kidney injury. Liver-specific CYP2E1 deletion reduced APAP hepatotoxicity, confirming the absence of hepatic NAPQI formation. Despite this protection, both male and female mice treated with AAV8-TBG-Cre and APAP developed progressive renal injury, with marked increases in blood urea nitrogen (BUN) and creatinine, tubular vacuolation, and strong induction of KIM-1 and osteopontin, along with apoptotic cell death at 48 hours. Notably, female mice, lacking renal CYP2E1 and displaying no detectable renal protein adducts, still progressed to AKI, demonstrating that kidney injury can occur through CYP-independent mechanisms. Given that APAP-induced AKI is a delayed injury, we further considered p-aminophenol (PAP), a deacetylation product of APAP, as a potential CYP-independent contributor. These findings support the concept that non-CYP pathways, including PAP formation, may contribute to kidney injury during the later phase of toxicity, although this pathway likely represents only one component of a multifactorial injury process. Together, these results demonstrate that APAP-induced AKI is a kidney-intrinsic process that can develop independently of both hepatic and renal CYP2E1 activity, emphasizing the need for kidney-specific therapeutic strategies for preventing APAP-induced renal injury.

Until now, there has been no animal-free alternative method for predicting chronic inflammation and delivering the associated dose responses, the timing of onset, and the duration of inflammation, as required by regulatory agencies. We present the results of pre-validation of an in-vitro-learned digital twin (InFiniteLungDT) capable of predicting chronic neutrophilic lung inflammation for regulatory use. The method is based on measuring the dynamics of early biological effects in vitro induced by respirable materials or their mixtures, without the need to know their intrinsic properties. We constructed the digital twin(s) for each of the material, for which we have in vivo exposure data. The instillation data set, comprising 49 different nanomaterials, was used as the primary anchor to calibrate the model. Inhalation data set, comprising 7 different nanomaterials, compliant with OECD TG 412, was used to show the general applicability of the method across species and for different exposure scenaria. In total, about 3094 single mouse exposures and 364 rat exposures (and approx. 775/225 non-exposed mouse/rat controls) were used to predict concentration-dependent time-evolved neutrophil influx into the lung. The accuracy (predictive capacity) of LOAEL determination is 93% for instillation and 84% for inhalation exposure. Taking into account the time-to-deliver-result being less than 1 week, this proves that the effect of inhaled material from acute to chronic conditions can be assessed orders of magnitude faster and cheaper than in a reference animal study.

Alternaria mycotoxins represent an emerging concern due to their frequent occurrence in food and feed. However, available toxicological data remain limited. Under the current EU regulatory framework, and in line with the EFSA/ECHA/JRC guidance for the identification of endocrine disruptors (EDs), assessment of endocrine activity relies on standardized assays performed according to OECD Test Guidelines (TGs) for the estrogen-, androgen- and steroidogenesis- (EAS) modalities. Within the framework of the European Partnership for the Assessment of Risks from Chemicals (PARC), standardized in vitro methods of regulatory relevance were performed for six chemically characterized Alternaria toxins, aiming to address current regulatory gaps on EAS-mediated activity. Alternariol (AOH), alternariol monomethyl ether (AME), tenuazonic acid (TeA), altertoxin-I (ATX-I), tentoxin (TEN) and altenuene (ALT) were assessed over a broad concentration range, from 0.001 up to 60 M, depending on cytotoxicity and solubility profile of each compound. Our findings indicate estrogenic activity for AOH (PC50: 3.9 - 4.6 {micro}M) and AME (PC50: 5.2 - 8.5 {micro}M) in the estrogen receptor transactivation assay (OECD TG 455), as well as an anti-estrogenic activity for ATX-I (IC30: 0.27 - 0.37 {micro}M). Minimal positive responses were observed at high concentrations for AOH (from the dose of 3 {micro}M) and for AME (from the dose of 10 {micro}M) in the agonistic part of the androgen receptor transactivation assay (OECD TG 458), which may also reflect glucocorticoid receptor activation. No effects on estradiol or testosterone production were observed for any of the tested Alternaria compounds in the steroidogenesis assay (OECD TG 456).

Of the cytochrome P450 enzymes, CYP3A4 is the most abundant isoform in the human liver, and this enzyme plays a dominant role in the metabolism of a wide range of clinical drugs and xenobiotics. Previous studies have demonstrated that CYP3A4 participates in the oxidative metabolism of several organophosphorus (OP) pesticides involving both thion (P=S) and oxon (P=O) forms. In the present study, we evaluated the capacity of CYP3A4 to metabolize a structurally diverse set of OP compounds using LC-MS/MS methods and assessed their potential to inhibit CYP3A4 activity using previously developed pFlour50 fluorogenic assay. Our results demonstrate that CYP3A4 preferentially metabolizes thions, as compared to oxons, and several OP compounds were also found to inhibit CYP3A4 activity in a time-dependent manner. To gain further mechanistic structural insight into the CYP3A4-OP interactions, molecular docking studies were performed using a crystal structure of CYP3A4 (PDB ID: 3NXU). Linear correlation analysis between in silico parameters like molecular weight or binding energy correlated with experimental data including inhibition data for 10 or 30 minutes or the LC-MS/MS data showing the degradation at 1 or 2 hours showed moderate but significant correlation. Soman surrogate PiMP, and cyclosarin surrogate CMP, were both effectively metabolized by CYP3A4, while docking of these surrogates and authentic agents with CYP3A4 receptor revealed very similar binding poses and interactions. Collectively, these findings highlight the important role of CYP3A4 in OP metabolism and support the potential of integrating experimental and in silico data to predict CYP3A4-mediated metabolism of existing and emerging OP compounds, including those of toxicological and chemical warfare relevance.

Acute kidney injury (AKI) affects millions of patients annually and is associated with high morbidity and mortality, to date no curative treatment exists. Drug-induced nephrotoxicity accounts for up to 25% of AKI cases, but individual susceptibility remains hard to predict. While genetic factors are suspected to play a part in this variability, the pharmacogenomics of nephrotoxin-induced kidney injury remain largely unknown. To investigate genetically determined susceptibility, we used precision-cut kidney slices (PCKS) from the two founder strains of the BXD mouse consortium, C57BL/6J and DBA/2J. PCKS preserves tissue architecture and cell-cell interaction, allowing close experimental control while maintaining the renal microenvironment. Slices were exposed to cyclosporine A (80 nM for 6h, 20nM for 24h and 48h) and Tunicamycin (1 {micro}M for 6h and for 24h) as well as normoxia (4{degrees}C for 20h) and hyperoxia (4{degrees}C for 20h and 4h in incubator). Slices were then analysed using histopathological scoring, TUNEL staining, ATP quantification and bulk RNA sequencing. We found that the main source of variation was experimental duration. Nevertheless, a subtle difference between the strains could be observed for both cyclosporine A and Tunicamycin, with DBA/2J showing a stronger response to nephrotoxic stress, including lower ATP levels, higher proportion of apoptotic cells and a more pronounced transcriptomic response. For both strains, normoxia was the least harmful condition. These findings support the hypothesis that the BXD founder strains differ in their susceptibility to nephrotoxic kidney injury and support the use of PCKS as a relevant ex vivo model for studying early renal stress response. This provides the foundation to extend this approach to a broader spectrum of the BXD population to identify genetic loci and candidate genes involved in genetic susceptibility to nephrotoxins.

Tenuazonic acid (TeA) is an emerging Alternaria mycotoxin frequently detected in food and feed commodities, raising concerns about its toxicological relevance. Chronic oral exposure to TeA has been reported to induce dysplastic alterations in the esophageal mucosa of mice, while human biomonitoring data indicate an association between TeA exposure and esophageal cancer, although a causal relationship has not yet been established. At a mechanistic level, the effects of TeA in esophageal cells remain poorly characterized. Therefore, this study investigated the impact of TeA on cytotoxicity, oxidative stress, DNA damage, mitochondrial homeostasis, cell-cycle distribution and transcriptomic stress responses in human esophageal KYSE-510 cells. TeA induced a concentration-dependent reduction in metabolic activity and total protein content after 24 h exposure to 0.1-100 M. Significant cytotoxicity was measured starting from 20 M. At sub-cytotoxic concentrations, TeA triggered rapid ROS formation within 5-30 min exposure and induced formamidopyrimidine-DNA glycosylase (FPG) sensitive DNA damage after 1 h exposure (5-7.5 M), indicating oxidative DNA lesions. In addition, TeA altered mitochondrial morphology after 4 h exposure at 7.5 M, manifested by shrinkage of the mitochondrial network area and perinuclear redistribution, while mitochondrial respiration showed only a non-significant tendency towards reduced respiratory capacity. RNA sequencing after 6 h exposure to 10 M TeA revealed oxidative stress-associated transcriptional changes, impaired antioxidant and stress-adaptive responses, and p53-associated stress signaling. Furthermore, TeA induced significant G2/M phase accumulation after 24 h exposure to 1-10 M.

Fluorinated chemicals are increasingly prevalent in pharmaceuticals and agrochemicals, yet their influence on the human gut microbiome and the potential for microbial biotransformation to alter therapeutic and toxicological profiles remain poorly understood. Here, we investigated the bidirectional relationship between 15 structurally diverse fluorinated chemicals and the gut microbiota by using an ex vivo high-throughput fermentation system. Screening revealed that flutamide, fluazinam, and pretomanid were consistently biotransformed across the donor microbiomes, while other compounds showed substantial inter-individual variability in degradation. Furthermore, exposure to fluorinated chemicals induced compound-specific shifts in microbial diversity and community composition, demonstrating their capacity to alter gut microbial ecology. Using a computational workflow combining in silico biotransformation predictions with untargeted LC-MS/MS analysis, we identified nitroreduction as the primary gut microbial transformation across all three compounds. Single-strain experiments confirmed that the nitroreduction of flutamide to flu-6, previously attributed only to hepatic metabolism, is a widespread capacity among gut bacterial strains. Finally, in vitro cytotoxicity assays and in silico modelling further revealed flu-6 to be a less hepatotoxic derivative than the parent compound, suggesting a potential detoxifying role for the gut microbiota. Together, these findings establish an integrated ex vivo, in vitro, and in silico approach for assessing the bidirectional interactions between fluorinated chemicals and the gut microbiome.

Inflammatory bowel diseases (IBD) affect millions of patients worldwide and impair quality of life. Although genetic and environmental factors are known to disrupt the gastrointestinal (GI) epithelial barrier and increase susceptibility to IBD, the precise contribution of specific environmental exposures remains unclear. Per- and polyfluoroalkyl substances (PFAS), or "forever chemicals," are widely used in consumer products and contaminate food and water sources, resulting in chronic oral exposure worldwide. Perfluorooctanoic acid (PFOA), a common PFAS, has been epidemiologically associated with the development of IBD, particularly in older adults. Here, we assessed the effects of oral PFOA exposure on the GI tract, liver, and susceptibility to colitis. C57BL/6 mice were exposed to PFOA (0.1 mg/kg or 1.0 mg/kg) beginning at weaning (post-natal day [P]21) for a time course of 4 or 8 weeks. GI physiology/pathology (Ussing chambers; histology), expression of pro-inflammatory cytokines (qPCR), microbiota composition (16S sequencing), bile acids production (qPCR; LC/MS), and liver pathology (histology) were assessed. Colitis susceptibility was evaluated in genetically predisposed (IL10 knockout) mice, and in induced (dextran sodium sulfate [DSS]) mouse models following PFOA exposure (8 weeks at 1.0 mg/kg). Oral PFOA exposure increased intestinal permeability, mildly increased cytokine expression, altered gut microbiota composition, disrupted liver and serum bile acids, and caused hepatic hypertrophy at higher doses and longer exposure. Although PFOA did not increase disease susceptibility in genetically predisposed Il10 KO mice, it significantly worsened DSS-induced colitis, but only in male mice. Together, these findings demonstrate that early-life PFOA exposure disrupts the gut-liver axis and may contribute to colitis development in a sex dependent manner.

Adverse outcome pathways (AOPs) describe stressor non-specific sequences of events between a first molecular trigger (molecular initiating event, MIE), causally linked key events (KEs), and an adverse outcome (AO). AOPs are intended to aid in chemical toxicity testing as a new approach methodology. However, commonly used AOP development methods depend on manual curation, which is labor intensive. As a result, there are still relatively few AOPs and a huge number of toxicity mechanisms and possible adverse outcomes remain undescribed. Therefore, systematic and high-throughput approaches to predict new AOPs are needed. Here, we developed and implemented a data integration-based framework to generate new candidate AOPs using insecticides and Parkinson Disease as a proof of concept. We integrated and statistically linked disconnected databases (e.g., Comparative Toxicogenomics Database, Human Protein Atlas, and Gene Ontology) to form MIE - KE (cell level) - KE (tissue level) - AO candidate AOPs. Through this systematic process, we generated 562,117 candidate AOPs, which we then scored using a weight of evidence (WoE) approach and prioritized 12,756 AOPs with a WoE >0.5. Through random sampling of 100 prioritized AOPs, we found 70% had external literature supporting their biological plausibility, and only 15% represented identifiably implausible associations. The prioritized AOPs describe varied mechanisms of toxicity related to e.g., MAPK, PTEN, and FGFR signaling pathways, with "increases phosphorylation of MAPK1" as the most frequent MIE. Our AOP generating approach yields consistently structured AOPs and can complement existing and emerging development methods to expand AOP coverage across different stressors and outcomes.

Introduction: Pediatric nicotine exposures remain an important and preventable public health issue, particularly with the rapid expansion of electronic nicotine delivery systems. This study compared demographic characteristics, exposure circumstances, and clinical outcomes between pediatric cases involving nicotine devices and bottled liquids reported to U.S. poison centers. Method: This retrospective cohort study analyzed National Poison Data System cases from 2011-2022 involving children aged less than 6 years exposed to nicotine devices or bottled liquids. Analyses were limited to cases with definitive medical outcomes. The primary outcome was defined as a moderate or major clinical effect or death. Odds ratios with 95% confidence intervals were calculated, with a secondary analysis restricted to route-concordant exposures. Results: The final cohort included 15,497 cases: 10,168 device exposures and 5,329 liquid exposures. Demographic characteristics were similar between groups. Device exposures more frequently involved inhalation, while ingestion predominated overall. Clinical effects were typically mild and transient, with vomiting and coughing most commonly reported. The primary outcome occurred in 1.9% of device cases and 2.0% of liquid cases (OR = 1.05; 95% CI 0.82-1.34). A secondary analysis restricted to inhalation-only device exposures and ingestion-only liquid exposures similarly found no significant difference in clinically important outcomes (OR = 1.38; 95% CI 0.92-2.12). Two deaths occurred, one in each group. Conclusion: These findings suggest that, despite differences in formulation and route of exposure, nicotine devices and bottled liquids produce broadly similar clinical toxicity profiles in young children. Prevention strategies should address all household nicotine products rather than focusing on specific delivery systems.

E-cigarettes have attracted significant attention as a safer substitute for conventional tobacco smoking. However, they have introduced new inhalable toxicants, including benzaldehyde-propylene glycol acetal (BPGA)--a chemical adduct produced by cherry-flavoured e-cigarettes. The health risks associated with such flavour-derived acetals remain insufficiently elucidated at the cellular level. This study investigated the role of BPGA in the progression of epithelial-to-mesenchymal transition (EMT)-like changes in alveolar epithelial cells (A549 cells). A549 cells exposed to various concentrations of BPGA were analysed for cell viability, morphology, mitochondrial function, lysosomal health, and cytoskeletal integrity using viability assays and fluorescence imaging. Intracellular reactive oxygen species (ROS) production was quantified using the 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA) assay. Antioxidant enzyme expression, inflammatory responses, and EMT-associated phenotypic alterations were evaluated using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunofluorescence (IF) assays. Exposure of alveolar epithelial cells to BPGA caused a concentration-dependent decrease in cell viability. BPGA exposure resulted in mitochondrial membrane depolarisation, lysosomal damage, cytoskeletal changes, and stress fibre formation, which altered cell morphology. It significantly increased intracellular ROS production. As a result, antioxidant enzyme levels were upregulated as a protective response. However, during severe oxidative stress, this response was overwhelmed. Excess ROS disrupted cellular homeostasis and initiated apoptosis, though not completely. ROS also acted as a signalling molecule, promoting the upregulation of inflammatory mediators. These changes were associated with altered EMT marker expression, suggesting that BPGA might drive EMT-like remodelling. In conclusion, BPGA, a chemical adduct from e-cigarette vapour, induces alveolar injury by promoting oxidative stress, inflammation, and EMT-related changes, which may explain a mechanism by which e-cigarette exposure could lead to lung injury and pulmonary fibrosis. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=169 SRC="FIGDIR/small/724520v1_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@f7739dorg.highwire.dtl.DTLVardef@1c74f11org.highwire.dtl.DTLVardef@180aeeorg.highwire.dtl.DTLVardef@75ae14_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstractC_FLOATNO C_FIG

Omics technologies are increasingly integrated into next-generation risk assessment, yet quantitative toxicogenomics outcomes remain highly dependent on analytical choices, motivating a systematic evaluation of how bioinformatics workflows influence hazard characterization and transcriptomic Points of Departure (tPOD). Here, we applied five independent transcriptomics pipelines to a shared dataset of RPTEC-TERT1 kidney cells exposed to cisplatin across multiple concentrations and timepoints, comparing effects of pre-processing, benchmark concentration modeling, and pathway-based interpretation strategies. Across workflows, substantial variability was observed in gene-level benchmark concentrations (BMCs), primarily driven by differences in normalization, filtering, and especially the modeling software used. Despite this variability, convergence increased at later timepoints as transcriptional responses strengthened, with 24 h consistently identified as the most sensitive timepoint at the gene level. Aggregation of gene-level BMCs into pathway-based metrics reduced variability but did not eliminate it, with pathway definition emerging as a major determinant of sensitivity estimates. Notably, distinct pathway resources showed minimal gene overlap, and smaller, biologically coherent gene sets (e.g., co-expression modules and biomarker panels) produced lower and less dispersed BMCs compared with broader pathway annotations. Furthermore, direct modeling of pathway activity scores yielded systematically different sensitivity estimates relative to median-based aggregation, with method-dependent conservativeness influenced by pathway coverage and response strength. Overall, our findings demonstrate that both analytical workflow design and pathway selection critically shape toxicogenomic-derived potency estimates, highlighting the need for harmonized, transparent methodologies to enable robust application of transcriptomics in chemical safety assessment and regulatory decision-making.

BackgroundPer- and polyfluoroalkyl substances (PFAS), particularly perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are persistent organic pollutants ubiquitous in the environment. Epidemiological evidence has closely linked them to an elevated risk of prostate cancer (PCa). However, the precise molecular mechanisms by which combined PFOS/PFOA exposure promotes prostate cancer and their dynamic effects on the tumor microenvironment remain unclear. MethodsThis study constructed a multi-module analytical framework integrating network pharmacology and computational biology: (1) Through ADMET toxicity prediction, multi-database target collection (three-way Venn analysis), panoramic GO/KEGG enrichment, focused androgen receptor (AR) axis analysis, GWAS genetic association validation, protein-protein interaction (PPI) network construction, machine learning-based independent screening, and a relaxed intersection strategy, we systematically identified PFOS/PFOA-prostate cancer core targets. (2) Subsequently, a PFAS-PTS score weighted purely by Cox coefficients was employed to drive gene set variation analysis (GSVA)-based pathway enrichment, tumor microenvironment (TME) deconvolution, ordinary differential equation (ODE)-based kinetic modeling, and drug intervention prediction. ResultsTarget collection identified 100 shared PFOS/PFOA-prostate cancer targets, from which 18 core targets were determined after multi-module screening. These targets were significantly enriched in the AR signaling axis, the PI3K-AKT pathway, and cell cycle regulation. Molecular docking confirmed strong binding affinities of PFOS/PFOA with AR (-9.49/-8.56 kcal/mol), AKT1 (-7.56/-6.93 kcal/mol), and PTEN (-6.36/-6.08 kcal/mol). GSVA revealed that the G2M checkpoint and E2F target gene pathways were significantly upregulated in the high-risk group (padj < 0.001), whereas the androgen response pathway was downregulated (padj = 4.8e-4). TME deconvolution (GSE141445, NNLS) revealed a significantly increased proportion of tumor cells (PCa) (p = 2.4e-4) and markedly reduced CD8+ T cell infiltration (p = 5.7e-4) in the high-risk group, indicating immunosuppressive microenvironment remodeling. ODE-based kinetic modeling confirmed that PFAS promoted tumor cell proliferation and suppressed immune surveillance in a dose-dependent manner. Drug intervention simulation demonstrated that the combination of enzalutamide and Alpelisib achieved optimal tumor cell inhibition (33.9% predicted by the ODE model). ConclusionPFOS/PFOA promote prostate cancer progression primarily through multi-target synergy involving AR axis disruption, PI3K-AKT pathway activation, and cell cycle dysregulation, while reshaping an immunosuppressive tumor microenvironment. The integrative computational framework established in this study provides systematic computational evidence for risk assessment and therapeutic intervention in PFAS-associated prostate cancer.

The preclinical safety of human-equivalent lactoferrin alpha (heqLF; effera(R)), produced by Komagataella phaffii, was evaluated to support its use as a food ingredient in infant formula and products for young children. Genotoxicity was assessed using a bacterial reverse mutation (Ames) assay in five strains of Salmonella typhimurium and Escherichia coli, and an in vitro micronucleus assay in TK6 cells. Both studies followed OECD guidelines and were conducted up to the recommended limit concentrations (5000 {micro}g/plate and 2000 {micro}g/mL, respectively). A 14-day non-GLP juvenile dose range-finding study and a 13-week GLP juvenile rat toxicity study with a 4-week recovery phase were conducted under ICH S11 guidance. Neonatal Sprague-Dawley rats received heqLF at 0, 1500, 3000, or 5000 mg/kg body weight/day by twice-daily oral gavage from postnatal day 7 to 98. Bovine lactoferrin (bLF) and whey protein at 5000 mg/kg body weight/day served as reference controls. heqLF was non-mutagenic and non-clastogenic in both genotoxicity assays. In the 13-week juvenile rat study, no heqLF-related mortality, clinical signs, developmental, neurobehavioral, or immune toxicity effects were observed. Minor, non-adverse renal findings consistent with high protein intake were observed and largely reversed during recovery. Clinical pathology parameters fully resolved during recovery. Toxicokinetic evaluation showed no systemic accumulation. Based on the absence of toxicologically relevant adverse findings, heqLF is well tolerated at doses up to 5000 mg/kg body weight/day, establishing a no observed adverse effect level (NOAEL) of 5000 mg/kg/day, the highest dose tested, and supporting its safety across intended populations from birth to adulthood.