Toxicol. Sci. [JOURNAL]
Sun
200 papers
Effects of urban PM2.5 on primary sinonasal epithelial cells in individuals with chronic rhinosinusitis.
Theorell J, Drnevich J, Verma V … +4 more , Salana S, Lee VS, Sargis RM, Veiga-Lopez A
Toxicol Sci · 2026 Jan · PMID 41071058 · Full text
Fine particulate matter (PM2.5), airborne particles with an aerodynamic diameter of ≤2.5 µm, a major air pollutant, has been implicated in sinonasal inflammatory diseases such as chronic rhinosinusitis (CRS) even at leve...
Fine particulate matter (PM2.5), airborne particles with an aerodynamic diameter of ≤2.5 µm, a major air pollutant, has been implicated in sinonasal inflammatory diseases such as chronic rhinosinusitis (CRS) even at levels below national air quality standards. PM2.5 is thought to exacerbate CRS by compromising the epithelial barrier, impairing mucociliary clearance, and promoting inflammation. However, evidence linking PM2.5 exposure to sinonasal epithelial remodeling remains limited. This study investigated the effects of environmentally relevant doses of urban PM2.5 organic extract (PM2.5 OE) on primary sinonasal epithelial cell cultures derived from individuals with and without CRS. We hypothesized that PM2.5 OE exposure would induce transcriptional changes indicative of mucociliary remodeling, reduce transepithelial resistance, and increase inflammatory cytokine production. Primary nasal epithelial cells from healthy (N = 8) and CRS subjects (N = 10) were differentiated in an air-liquid interface, followed by acute (24-h) and subacute (5-day) exposure to an environmentally relevant dose of PM2.5 OE (9 μg/ml; 1.34 µg/cm2) or the vehicle control. PM2.5 OE exposure did not significantly alter these outcomes, regardless of disease status. Instead, variation was primarily driven by biological sex and CRS, with male CRS samples exhibiting downregulation of cilia assembly pathways. Cytokine production from unexposed cultures demonstrated sex-specific differences, with female-derived cultures displaying a more pro-inflammatory profile, highlighting intrinsic immune variability. These findings underscore the importance of biological sex and disease status when evaluating environmental exposures, suggesting that longer exposures may be necessary to fully capture PM2.5 OE-induced effects. This work highlights the need to investigate the crosstalk between environmental exposures and individual-specific factors influencing CRS disease progression.
The differential toxicity of three different oxidized nickel compound nanoparticles and the effects of particle surface ligands in mouse alveolar macrophages.
Kendall RL, Hamilton RF, Albright JM … +6 more , Zhao Y, Hang Y, Tang C, Porter D, Wu N, Holian A
Toxicol Sci · 2025 Dec · PMID 41060044 · Full text
Nickel-compound engineered nanomaterials (Ni-X NP) have diverse applications, yet their continued use raises concerns for potential health impacts upon exposure. This study investigated 3 structurally distinct Ni-X-NP-pu...
Nickel-compound engineered nanomaterials (Ni-X NP) have diverse applications, yet their continued use raises concerns for potential health impacts upon exposure. This study investigated 3 structurally distinct Ni-X-NP-pure NiO (NCZ), NiO@Ni(OH)2 (SIG), and Ni@NiO@Ni(OH)2 (AA)-to determine how core composition and surface functionalization contribute to bioactivity. Each Ni-X NP was modified with surface moieties (-OH, -COOH, and -CH3) to assess the efficacy of surface modifications in reducing bioactivity. Ni-X NP were thoroughly characterized for structure, surface chemistry, and Ni2+ ion release in simulated lysosomal fluid. Red blood cells (RBCs) were used to evaluate the hemolytic capabilities of the nanoparticles, and primary murine alveolar macrophages (AM), and murine ex vivo alveolar macrophages (mexAM) were used to assess uptake, cytotoxicity, IL-1β release, and lysosomal membrane permeability (LMP). Results showed that NiO@Ni(OH)2 nanoparticles induced the greatest hemolysis in RBC, elicited the greatest IL-1β response in AM and mexAM, and produced the most LMP in mexAM. The Ni@NiO@Ni(OH)2 nanoparticle released the most Ni2+ and caused profound reductions in AM cell viability but failed to cause RBC hemolysis or LMP. Pure NiO nanoparticles exhibited minimal bioactivity and low Ni2+ release. Surface modification with (-COOH) or (-CH3) effectively reduced bioactivity in LMP-mediated inflammation but had minimal effect on Ni2+-driven toxicity. This study reveals that Ni-X NP bioactivity depends on both core composition and surface chemistry, and that surface functionalization reduces inflammation only when lysosomal damage is the primary driver. These findings underscore the need for careful design and evaluation of engineered nanomaterials.
TGx-DDI (toxicogenomic DNA damage-inducing) biomarker validation: multi-site ring trial supporting regulatory use.
Wang X, Crute CE, Allemang A … +14 more , Aubrecht J, Burleson F, Dietz-Baum Y, Dorsheimer L, Fornace AJ, Frötschl R, Hemmann U, Mitchell CA, Pfuhler S, Williams A, Lin LY, Pettit S, Yauk CL, Li HH
Toxicol Sci · 2025 Dec · PMID 41031489 · Full text
Standard in vitro genotoxicity assays often suffer from low specificity, leading to irrelevant positive findings that require costly in vivo follow-up studies. The TGx-DDI (Toxicogenomic DNA Damage-Inducing) transcriptom...
Standard in vitro genotoxicity assays often suffer from low specificity, leading to irrelevant positive findings that require costly in vivo follow-up studies. The TGx-DDI (Toxicogenomic DNA Damage-Inducing) transcriptomic biomarker was developed to address this limitation by identifying DNA damage-inducing compounds through gene expression profiling in human TK6 lymphoblastoid cells. To qualify TGx-DDI as a reliable, reproducible biomarker for augmenting genotoxicity hazard assessment, a multi-site ring-trial was conducted across four laboratories using 14 blinded test compounds and standardized protocols. TK6 cells were exposed to three concentrations of each compound, followed by RNA extraction and digital nucleic acid counting using the NanoString nCounter platform. A three-pronged bioinformatics approach-Nearest Shrunken Centroid Probability Analysis, Principal Component Analysis, and Hierarchical Clustering-was used to assign DDI or non-DDI classifications. TGx-DDI demonstrated 100% sensitivity, 86% specificity, and 91% accuracy in distinguishing DDI from non-DDI compounds under validated test conditions. High interlaboratory concordance was observed (agreement coefficients ≥0.61), and transcriptomic data showed strong cross-site correlation (Pearson r > 0.84). The biomarker reproducibly classified test agents even when conducted across study sites. These results demonstrate that TGx-DDI is a robust and reproducible transcriptomic biomarker that enhances the specificity of genotoxicity testing by distinguishing biologically relevant DNA damage responses. Its integration into genotoxicity testing strategies can support regulatory decision-making, reduce unnecessary animal use, and improve the assessment of human health risks.
Advanced cardiotoxicity profiling using field potential imaging with UHD-CMOS-MEA in human iPSC-derived cardiomyocytes.
Matsuda N, Nagafuku N, Matsuda K … +6 more , Ishibashi Y, Taniguchi T, Matsushita Y, Miyamoto N, Yoshinaga T, Suzuki I
Toxicol Sci · 2025 Dec · PMID 41026851 · Full text
Accurate assessment of cardiotoxicity using human induced pluripotent stem cell (iPSC)-derived cardiomyocytes is critical for ensuring drug safety during preclinical development. However, existing in vitro methodologies...
Accurate assessment of cardiotoxicity using human induced pluripotent stem cell (iPSC)-derived cardiomyocytes is critical for ensuring drug safety during preclinical development. However, existing in vitro methodologies predominantly focus on QT interval prolongation and arrhythmia risk, often lacking the capacity to capture the complex interplay among multiple ion channels or to detect early manifestations of chronic cardiotoxicity-both of which are essential for evaluating long-term cardiac safety. Moreover, reliable prediction of pharmacological mechanisms of action remains a significant challenge. In this study, we employed field potential imaging utilizing an ultra-high-density complementary metal-oxide-semiconductor microelectrode array (MEA) comprising 236,880 electrodes distributed across a 5.9 × 5.5 mm active area. With 91.9% surface coverage by 11 μm electrodes spaced at 0.25 μm, the platform achieves near single-cell resolution across the entire cardiomyocyte monolayer. This system enabled the extraction of high-resolution electrophysiological endpoints, including the number and spatial variability of excitation origins, conduction velocity, and propagation area-thereby extending the analytical capabilities beyond those of conventional MEAs. Pharmacological testing revealed compound-specific alterations: Isoproterenol increased excitation origins, mexiletine reduced conduction velocity, and E-4031 diminished propagation area. Although these agents are well characterized, their effects were visualized with unprecedented spatiotemporal resolution, reflecting their underlying mechanisms of action. Multivariate analysis incorporating both conventional and novel endpoints enabled accurate classification of mechanisms under acute conditions. Furthermore, chronic cardiotoxicity induced by low-dose doxorubicin (0.03 μM) was sensitively detected within 24 h-earlier and at lower concentrations than previously reported-based on significant reductions in conduction velocity and propagation area. Collectively, these findings establish a high-resolution, mechanism-aware framework for in vitro cardiotoxicity profiling, offering improved predictive accuracy by capturing multi-ion channel interactions, spatial conduction abnormalities, and early signs of chronic dysfunction.
Beyond QSARs: Quantitative Knowledge-Activity Relationships (QKARs) for enhanced drug toxicity prediction.
Li T, Qu Y, Chen A … +3 more , Thakkar S, Li D, Tong W
Toxicol Sci · 2025 Dec · PMID 41025529 · Full text
Computational toxicology plays an important role in risk assessment and drug safety. The field has been traditionally dominated by Quantitative Structure-Activity Relationships (QSARs), which predict toxicological effect...
Computational toxicology plays an important role in risk assessment and drug safety. The field has been traditionally dominated by Quantitative Structure-Activity Relationships (QSARs), which predict toxicological effects based solely on chemical structure. Although QSARs have achieved successes, their structure reliance limits drug toxicity predictions, where small structural modifications may cause major toxicity changes. Advances in artificial intelligence (AI), especially text embedding and generative AI, provide an opportunity to enhance toxicity predictions by leveraging broader chemical knowledge and its integration with structural data. In this study, we propose a novel framework, Quantitative Knowledge-Activity Relationships (QKARs), which predicts toxicity using domain-specific knowledge. We developed QKAR models for two drug toxicity endpoints, drug-induced liver injury (DILI) and drug-induced cardiotoxicity (DICT), using three different knowledge representations with varying levels of knowledge. The representations based on comprehensive knowledge of the drugs yielded better prediction than those with simpler knowledge. Five machine learning algorithms of distinct complexity were applied in QKAR models, and we observed little association between model complexity and performance. Further, we evaluated QKARs against QSARs on the same endpoints using identical datasets. We found that QKARs consistently outperformed QSARs for DILI and DICT. Notably, QKARs demonstrated better capability than QSARs in differentiating drugs with similar structures but different liver toxicity profiles. We also investigated integrating knowledge-based and structure-based representations, Q(K + S)ARs, for further enhanced prediction accuracy. Our findings demonstrate the potential of QKARs as a robust alternative to QSARs, offering additional opportunities in drug toxicity assessments by leveraging both domain-specific knowledge and structural data.
Exploration of oxidative stress-mediated genetic toxicology modes of action using a pathway analysis, Connectivity Mapping, and transcriptional benchmark dosing-based framework.
De Abrew KN, Selman BG, Shobair M … +3 more , Zhang X, Allemang AJ, Pfuhler S
Toxicol Sci · 2025 Dec · PMID 41017723 · Publisher ↗
Although current genetic toxicology practices can detect downstream genotoxicity effects, such as gene mutation and double-strand breaks, they are unable to detect the underlying mode of action (MoA) of a chemical or dif...
Although current genetic toxicology practices can detect downstream genotoxicity effects, such as gene mutation and double-strand breaks, they are unable to detect the underlying mode of action (MoA) of a chemical or differentiate between direct- and indirect-acting genotoxicants without additional modification. The Adverse Outcome Pathway (AOP) framework is a useful tool to critically identify and evaluate MoAs and can enable subsequent quantitative dose-response assessments of genotoxicity endpoints. The recently developed AOP, "Oxidative DNA damage leading to chromosomal aberrations and mutations" (https://aopwiki.org/aops/296), pertains to 1 common genetic toxicology-relevant MoA: Oxidative stress. Reactive oxygen species (ROS) play a key role in regulating many biological processes; however, when disrupted, an excess of ROS can eventually lead to DNA damage and double-strand breaks. Here, we look at 18 compounds reported to have complete or mixed oxidative stress MoAs and use a combination of genomic tools such as Pathway analysis, Connectivity Mapping (CMap), and Transcriptional benchmark dose modeling to define a framework that can separate substances that test negative in vivo from true in vivo genotoxicants. TK6 cells were treated with the 18 compounds for 4 h, parallel micronucleus and genomics experiments were performed, and in vitro micronucleus data were used to infer dose for genomics analysis. The resulting genomic data were analyzed using pathway analysis for hypothesis generation; these hypotheses were tested using CMap and Transcriptional benchmark dose modeling. We demonstrate that a genomics-based workflow based on in vitro methods can be used to successfully separate in vivo genotoxicants from non-genotoxicants. These methods have the potential to evolve into Next Generation Risk Assessment tools that can be used for determining the contribution of the oxidative stress MoA in a predictive toxicology setting.
High-content toxicological profiling of 87 compounds using a 3D mouse mini-testis model: a New Approach Methodology (NAM) for prioritizing male reproductive toxicants.
Yin L, Hu JC, Xia M … +1 more , Yu XJ
Toxicol Sci · 2025 Dec · PMID 41017718 · Full text
Environmental exposure to industrial chemicals, endocrine disruptors, and pharmaceuticals has been increasingly linked to the global decline in male reproductive health. To address the urgent need for efficient and mecha...
Environmental exposure to industrial chemicals, endocrine disruptors, and pharmaceuticals has been increasingly linked to the global decline in male reproductive health. To address the urgent need for efficient and mechanistically informed toxicity screening, we developed a high-throughput screening, high-content analysis (HCA) platform using a 3D in vitro mini-testis model. This system was used to evaluate 87 structurally diverse compounds from the National Toxicology Program chemical library. The model incorporates murine-derived spermatogonia, Sertoli, and Leydig cells embedded in an extracellular matrix, providing a physiologically relevant environment for mechanistic toxicology. Each compound was tested across 10 phenotypic endpoints, including nuclear morphology, cytoskeletal integrity (F-actin), DNA damage (γH2AX), and cell viability by using high-content imaging. Quantitative Points of Departure (PODs) were calculated and integrated into a High-Content Assay Index. Toxicological Priority Index (ToxPi) scores, derived from the PODs, enabled compound ranking and clustering. Compared with existing in vivo reproductive toxicity data, the 3D model demonstrated 91.5% sensitivity, 93.8% specificity, and 93.6% concordance (n = 64 compounds). Notably, 22 compounds lacking reproductive toxicity data were identified as potentially reproductive toxicants. Mechanistic analyses revealed that nuclear morphology, F-actin intensity, and γH2AX were the most sensitive indicators of reproductive toxicity. Cluster and category-level analysis showed that flame retardants and pesticides ranked highest in toxicity. The integration of multi-parametric data via ToxPi facilitated high-resolution chemical prioritization. Given current ethical and technical challenges in sourcing human testicular tissue or differentiating stem cells into testicular cell types, murine cells provide a reproducible and practical alternative for complex multicellular testis modeling. Our results demonstrate that the HCA-integrated 3D mini-testis model offers a robust, scalable, and mechanistically insightful platform for male reproductive toxicity screening, supporting its adoption as New Approach Methodologies aligned with regulatory and ethical testing goals.
Investigation of bone toxicity in drug development: review of current and emerging technologies.
Tuladhar A, Guffroy M, Finnema SJ … +4 more , Christmann R, Van Vleet TR, Mayana SAK, Fossey S
Toxicol Sci · 2025 Dec · PMID 41002228 · Publisher ↗
Assessment and characterization of bone toxicity during drug development is important to ensure the safety of new therapeutics. Drugs can affect bone composition and quality either directly on bone cells or indirectly vi...
Assessment and characterization of bone toxicity during drug development is important to ensure the safety of new therapeutics. Drugs can affect bone composition and quality either directly on bone cells or indirectly via systemic effects, leading to alterations in bone density, remodeling, and fracture risk. Drug classes known to have harmful effects on bone include antidiabetics, non-steroidal anti-inflammatory drugs, antivirals, chemotherapeutics, and steroids. Various methods are available to assess and investigate bone toxicity, including in vivo animal models, ex vivo organ cultures, and in vitro cell cultures. In addition to routine assessment with in vivo animal models using microscopic examination of bone and clinical pathology parameters (calcium, phosphorus, and alkaline phosphatase), other tools such as serum biomarkers of bone turnover, advanced imaging approaches, and histomorphometric analyses provide additional insight into bone microarchitecture and the remodeling process. Emerging in vitro methods, such as microphysiological systems (organ-on-a-chip) technologies simulating bone's dynamic environment, offer toxicologists useful tools to study drug-induced bone toxicity. In silico models are increasingly recognized as critical tools in assessing drug-induced bone toxicity, offering a complementary approach to traditional in vitro and in vivo methods. Mechanistic models, such as pharmacokinetic-pharmacodynamic frameworks, simulate remodeling dynamics and simulate drug metabolism and exposure to explore the risk of bone and cartilage toxicity, whereas finite element models simulate cellular interactions and mechanical stress responses for skeletal toxicity predictions. This review aims to evaluate key features of bone biology impacted by therapeutics with examples and describe techniques for assessing bone toxicity during drug development.
In vitro models of the male reproductive system: applications for developmental and reproductive toxicology.
Hansen BC, Aryeh KS, Lindell LX … +4 more , Lau GK, Nicholson TM, Faustman EM, Kelly EJ
Toxicol Sci · 2025 Dec · PMID 41002216 · Publisher ↗
There is a paucity of in vitro models to study the male reproductive system. Proper function of the reproductive system is critical for endocrine function, growth and development, and fertility. Without practical in vitr...
There is a paucity of in vitro models to study the male reproductive system. Proper function of the reproductive system is critical for endocrine function, growth and development, and fertility. Without practical in vitro screening models, reproductive toxicities can be missed in early drug development or standard toxicological batteries. Successful in vitro models of the male reproductive system need to recapitulate the dynamic nature of the testis, considering the formation of the testicular niches from gonadal differentiation through puberty and the post-pubertal activity of the paracrine and endocrine signals that support spermatogenesis. In vitro approaches are reviewed that model primordial germ cell differentiation, gonadal morphogenesis, fetal steroidogenesis, neonatal reproductive development, and adult testicular niche dynamics to present opportunities for inclusion of male reproductive toxicity screening within a toxicological battery. The utility of cells derived from model organisms, differentiated from induced pluripotent stem cells, and obtained from donated human tissue is discussed. The field of reproductive and developmental toxicology is primed for expansion in in-vitro model availability as complex in-vitro model development continues to accelerate, and fit-for-purpose model approaches are adopted in toxicological and drug development pipelines. This review highlights the current limitations and emerging opportunities in male reproductive in vitro models, providing a roadmap for integrating these systems into toxicology testing and drug development workflows. It highlights the need for developmentally benchmarked, physiologically relevant, and multicellular models to fill existing gaps and improve translatability.
Streamlined format for Toxicological Sciences: still your science, your journal.
Kaplan BL, Peters JM
Toxicol Sci · 2025 Dec · PMID 40991919 · Publisher ↗
Abstract loading — click title to view on PubMed.
Pharmacokinetics of cannabidiol and its metabolites in rhesus monkeys and New Zealand White rabbits.
Wu Q, Camacho L, Talpos J … +7 more , Shpyleva S, Mellon RD, Fisher JE, Vanlandingham M, Shores P, Gamboa da Costa G, Beland FA
Toxicol Sci · 2025 Dec · PMID 40973479 · Publisher ↗
Cannabidiol (CBD) is extensively metabolized in humans, with 7-carboxy-CBD being the major metabolite. The biotransformation of CBD in mice, rats, and dogs differs from that in humans. We have investigated if the pharmac...
Cannabidiol (CBD) is extensively metabolized in humans, with 7-carboxy-CBD being the major metabolite. The biotransformation of CBD in mice, rats, and dogs differs from that in humans. We have investigated if the pharmacokinetics of CBD in rhesus monkeys and New Zealand White rabbits is similar to humans by measuring serum levels of CBD and its phase I and II metabolites after single intragastric (77.5 mg/kg body weight) or intravenous (3.9 mg/kg body weight) CBD doses. In rhesus monkeys, intragastric CBD yielded a maximum concentration (Cmax) of 241.6 nM (males) and 476.5 nM (females), with a terminal half-life (T1/2) of 11.6 and 15.4 h. The area under the curve from zero to infinity (AUC0-inf) was 5,376 nM*h (males) and 7,366 nM*h (females), with bioavailability of 2.5% and 5.5%. 7-Carboxy-CBD showed a Cmax of 334.7 nM (males) and 655.4 nM (females), with AUC0-inf 1.5 to 1.6 times higher than CBD. The levels of other metabolites were minimal. In rabbits, intragastric CBD resulted in a Cmax of 76.6 nM (males) and 117.1 nM (females), with a T1/2 of 11.1 and 14.9 h. The AUC0-inf was 1,443 nM*h (males) and 1,645 nM*h (females), with bioavailability of 2.1% to 2.2%. 7-Carboxy-CBD levels were significantly higher than CBD, with a Cmax of 11,631 nM (males) and 13,278 nM (females), and an AUC0-inf 120 to 133 times higher. In contrast to rhesus monkeys, New Zealand White rabbits exhibit a CBD metabolic profile similar to humans, with high levels of 7-carboxy-CBD, making them a promising model for studying CBD metabolism-driven toxicity.
The OASIS Consortium: integrating multi-omics technologies to transform chemical safety assessment.
Rouquié D, Bender A, Cheah J … +13 more , Crute CE, Dalmas D, Ewald J, Fullerton A, Harrill JA, Kadri S, Kleinstreuer N, Kramer N, LaRocca J, Mitchell CA, Seal S, Singh S, Carpenter AE
Toxicol Sci · 2025 Dec · PMID 40971841 · Full text
Next Generation Risk Assessment (NGRA) aims to improve safety testing of pharmaceuticals, agrochemicals, and industrial chemicals. NGRA employs new approach methodologies, such as novel in vitro assays coupled with expos...
Next Generation Risk Assessment (NGRA) aims to improve safety testing of pharmaceuticals, agrochemicals, and industrial chemicals. NGRA employs new approach methodologies, such as novel in vitro assays coupled with exposure modeling, to minimize the use of animal models, which can fail to predict specific biological effects in humans. The strategy of the 'Omics for Assessing Signatures for Integrated Safety (OASIS) Consortium combines multi-omics technologies (including transcriptomics, proteomics, and Cell Painting [high-content imaging]) and multiple cell model systems (ranging from simple cell cultures to complex organotypic models). By integrating these approaches with internal exposure estimates, the consortium aims to improve the translation between in vitro and in vivo test systems, ultimately enhancing the relevance of safety assessment to human biology. OASIS's integrated approach aims to better translate the biological effects across different chemical and biological spaces, starting with the liver as a use case. By using compounds with well-characterized in vivo and in vitro nonclinical safety and toxicology data related to adverse organ-specific effects in rats and humans, OASIS aims to create novel integrated methods that improve safety assessment while reducing animal use. Ideally, these efforts will contribute to regulatory science across sectors and support the adoption of more predictive, efficient, and cost-effective toxicological models.
Zebrafish cell lines and high-throughput transcriptomics: advancing in vitro and bioinformatics methods for supporting environmental risk assessment.
Schumann PG, Bundy J, Haggard DE … +9 more , Everett L, Harrill JA, Harris F, Ryoo D, Collins J, Rivetti C, Campos B, Hodges G, LaLone CA
Toxicol Sci · 2025 Dec · PMID 40971701 · Full text
Historic animal-based toxicity testing methods cannot keep pace with the need for prioritizing new and existing chemicals for comprehensive risk assessment. New approach methodologies such as high-throughput in vitro tra...
Historic animal-based toxicity testing methods cannot keep pace with the need for prioritizing new and existing chemicals for comprehensive risk assessment. New approach methodologies such as high-throughput in vitro transcriptomics screening have emerged to address this challenge. However, most in vitro methods were developed using mammalian cell lines, including human, and may not adequately represent environmental species, potentially limiting the utility of this methodology for supporting environmental risk assessment. The objective of this study was to evaluate whether zebrafish cell lines can generate biologically meaningful chemical effects data in a high-throughput transcriptomics pipeline that is protective of toxicologically relevant aquatic apical endpoints. Forty-two test chemicals were screened in 2 commercially available zebrafish cell lines (ZFL liver and ZEM2S embryonic fibroblast) using the TempO-Seq zS1500+ platform. Transcriptomic points-of-departure (tPODs) were derived using 2 methods: Gene-level analysis (tPODgenes) with BMDExpress software and biological pathway-altering concentrations (BPACs/tPODsignatures) from signature-based dose-response analysis. When converted to predicted external water concentrations using quantitative in vitro-in vivo extrapolation models, tPODs were generally protective of aquatic in vivo endpoints from the ECOTOX Knowledgebase. Differential gene expression and biological pathway analysis revealed potential cell-type-specific effects for several chemicals, highlighting the value of using multiple cell types for capturing tissue-specific responses. Lastly, the biological pathway information was used to extrapolate the chemical effects data across species through an integration of protein-protein interaction network analysis and the Sequence Alignment to Predict Across Species Susceptibility tool, which has significant implications for improving the ecological relevance of these methods.
Testing the effects of two different zebrafish exposure paradigms on transcriptomic-based chemical risk assessment using the flame retardant triphenyl phosphate.
Morash MG, Kirzinger MW, Achenbach JC … +8 more , Venkatachalam AB, Hui JPM, Penny S, Stemmler K, Cooper JP, Ratzlaff DE, Woodland CLA, Ellis LD
Toxicol Sci · 2025 Nov · PMID 40924570 · Full text
In the zebrafish larval toxicity model, phenotypic changes induced by chemical exposure can potentially be explained and predicted by the analysis of gene expression changes at sub-phenotypic concentrations. The increase...
In the zebrafish larval toxicity model, phenotypic changes induced by chemical exposure can potentially be explained and predicted by the analysis of gene expression changes at sub-phenotypic concentrations. The increase in knowledge of gene pathway-specific effects arising from the zebrafish transcriptomic model has the potential to enhance the role of the larval zebrafish as a component of Integrated Approaches to Testing and Assessment (IATA). In this paper, we compared the transcriptomic responses to triphenyl phosphate between 2 standard exposure paradigms, the Zebrafish Embryo Toxicity (ZET) and General and Behavioral Toxicity (GBT) assays. The ZET assay represents a developmental model with chemical exposure from 6 to 120 h post fertilization (hpf), which covers organogenesis, whereas the GBT represents a juvenile model with exposure from 72 to 120 hpf, which occurs post-organogenesis. This comparison demonstrates both similarities and differences between the 2 assays. Although both models identified similar xenobiotic metabolism pathways, the difference in exposure window length and the time of transcriptomic sampling between the 2 methods also yielded unique sets of affected pathways, demonstrating their complimentary nature. Both data sets support previously described effects of triphenyl phosphate on aquatic and mammalian systems. This work validates and strengthens the use of both exposure paradigms and continues to demonstrate that zebrafish larvae are a valuable tool in the context of IATA toward reduced reliance on the use of higher vertebrate derived data for chemical risk assessment.
Context-dependent contribution of peptidyl arginine deiminase 4 (PAD4) to neutrophil extracellular trap formation and liver injury in acute and chronic hepatotoxicant challenge.
Capece GE, Patel AK, Hu D … +7 more , Roychowdhury T, Hazel B, Kothapalli J, Mac NA, Denorme F, Campbell RA, Poole LG
Toxicol Sci · 2025 Nov · PMID 40924556 · Full text
Neutrophils play a complex role in the pathogenesis of chronic liver disease and have been linked to both liver damage and injury resolution. Recent reports propose that neutrophils drive liver injury and fibrosis throug...
Neutrophils play a complex role in the pathogenesis of chronic liver disease and have been linked to both liver damage and injury resolution. Recent reports propose that neutrophils drive liver injury and fibrosis through the formation of neutrophil extracellular traps (NETs). This study tests the hypothesis that the enzyme peptidyl arginine deiminase-4 (PAD4) drives NET formation and liver fibrosis in experimental chronic liver injury. Wild-type (PAD4+/+) and PAD4-deficient (PAD4-/-) mice were chronically challenged twice weekly with carbon tetrachloride (CCl4, 1 ml/kg, i.p) or vehicle (corn oil) for 6 weeks, and samples were collected 24 h after the final challenge. In separate studies, mice were challenged once, and samples were collected 24 to 48 h later. Circulating NET biomarkers (e.g. myeloperoxidase-DNA complexes) were elevated in chronic CCl4-challenged wild-type mice compared to vehicle, though surprisingly, intrahepatic NETs were rarely observed. In contrast to our hypothesis, PAD4 deficiency did not eliminate circulating NET markers in chronic challenge. Furthermore, PAD4 deficiency did not impact liver fibrosis assessed by picrosirius red labeling or the myofibroblast marker α-smooth muscle actin but caused a modest, sex-specific decrease in hepatic collagen type I immunolabeling. Interestingly, plasma NET biomarkers and intrahepatic NETs were both increased following acute CCl4 challenge in a PAD4-dependent manner. Furthermore, PAD4 deficiency reduced coagulation activity after 24 h and decreased hepatocellular necrosis 48 h after challenge. Our studies ultimately suggest that PAD4 affects liver injury uniquely, depending on the stage of disease and that mechanisms of NET formation may occur independent of PAD4 in chronic liver injury.
ToxPoint: The case for Equilibrative Nucleoside Transporters in current regulatory guidance.
Martinez-Guerrero L, Tang X, Ekins S … +2 more , Wright SH, Cherrington NJ
Toxicol Sci · 2025 Nov · PMID 40900667 · Full text
Abstract loading — click title to view on PubMed.
ToxPoint: The indispensable role of zebrafish as a new approach methodology (NAM) in toxicology.
Tanguay RL
Toxicol Sci · 2025 Nov · PMID 40889284 · Full text
Abstract loading — click title to view on PubMed.
Rat and dog quad-culture liver chip models: characterization and use to interrogate a potential flavin-containing monooxygenase-mediated, species-specific toxicity of a histamine receptor antagonist.
Kukla DA, Sharapova TA, Ciurlionis R … +8 more , Van Vleet T, Wetter JM, Peterkin VC, Lee AJ, Marsh KC, Wang Y, Mahalingaiah PKS, Stresser DM
Toxicol Sci · 2025 Oct · PMID 40880281 · Publisher ↗
Microphysiological systems (MPS) contain multiple cell types in three dimensions and often incorporate fluidic shear forces. There is interest in MPS for disease and efficacy modeling, safety and disposition studies. Ani...
Microphysiological systems (MPS) contain multiple cell types in three dimensions and often incorporate fluidic shear forces. There is interest in MPS for disease and efficacy modeling, safety and disposition studies. Animal cell-based MPS are needed to provide confidence in the translation of data from human cell-based MPS. We developed rat and dog quad-culture liver MPS incorporating primary hepatocytes, sinusoidal endothelial, Kupffer, and stellate cells. Using cryopreserved primary cells, we established a protocol for co-culturing cells under physiological flow conditions. Cells were evaluated for viability, morphology, and function (e.g. albumin production, cytochrome P450, and flavin-containing monooxygenase [FMO] activity). Optimized culture conditions maintained high-quality rat and dog liver chips for up to 7 days. Model performance was evaluated with ABT-288, a histamine-3 receptor antagonist that caused elevated serum transaminases in dogs but not rats. This finding was partially attributed to the high levels of FMO-mediated N-oxide metabolites produced in the dog. Key findings in our study were (i) dog chips showed much higher FMO-mediated N-oxidation compared with rat, and (2) dog chips exhibited modestly higher sensitivity to ABT-288 toxicity endpoints (albumin, alanine transaminase, and lactate dehydrogenase) compared with rat. Species differences in N-oxidation were not observed in rat and dog liver microsomes or 2D hepatocyte monocultures, suggesting that properties of the quad-culture MPS were necessary to model higher FMO activity observed in dogs in vivo. The data suggest that this preclinical species liver chip model provides novel understanding of in vitro to in vivo translation of ABT-288 dog liver toxicity.
Estimation of benchmark dose ratio distributions for subchronic-to-chronic extrapolation using meta-analysis.
Blessinger T, Fox J, Dean J
Toxicol Sci · 2025 Nov · PMID 40854148 · Full text
Recently, the International Programme on Chemical Safety (IPCS) developed a unified probabilistic framework for deriving reference values and a software tool, Approximate Probabilistic Analysis (APROBA), to help implemen...
Recently, the International Programme on Chemical Safety (IPCS) developed a unified probabilistic framework for deriving reference values and a software tool, Approximate Probabilistic Analysis (APROBA), to help implement this framework. The distributions of multiple sources of uncertainty and variability were estimated, including uncertainty when extrapolating from subchronic to chronic data. The subchronic-to-chronic distribution was estimated using ratios between subchronic and chronic benchmark doses (BMDs) and was determined to be approximately lognormal, with parameter values reported by IPCS. These parameters were estimated largely from historical data on body and organ weights from toxicological studies. We estimated the distribution using a larger collection of data, including histopathological and clinical endpoints. Our analysis determined that key assumptions of the method and the default values in APROBA are consistent with the results from the new data. However, the uncertainty of predictions for dichotomous response data was greater than assumed in APROBA, and the reference values derived using our new results were lower than those derived from APROBA (by 25% in an example case). Also, APROBA's default parameter values do not account fully for the uncertainty of predicted chronic BMDs. Most importantly, the uncertainty of the prediction can be much greater than assumed in APROBA if BMDs are accepted when they fall well outside the observed dose range or when an upper confidence limit is not quantifiable. Careful evaluation of dose-response model fit, including a number of indicators of model suitability in addition to standard goodness-of-fit statistics, is necessary to improve quantification of uncertainty.
Navigating complexity in modern toxicology: the role of omics in short-term in vivo studies.
Mitchell CA, Wehmas L, Rouquié D … +3 more , Caiment F, Currie RA, Crute CE
Toxicol Sci · 2025 Nov · PMID 40854116 · Full text
Toxicology is shifting toward predictive, mechanism-based approaches that support quicker, more human-relevant risk assessments and reduce reliance on animal testing. Central to this shift are short-term in vivo studies...
Toxicology is shifting toward predictive, mechanism-based approaches that support quicker, more human-relevant risk assessments and reduce reliance on animal testing. Central to this shift are short-term in vivo studies enriched with omics endpoints, which provide early molecular indicators of toxicity. These data enable the derivation of molecular points of departure and other biologically anchored metrics that can inform potency ranking, hazard identification, and risk assessment. This commentary summarizes insights from the 2025 Society of Toxicology session of the same name and highlights the importance of aligning technical advances with regulatory needs. Next-Generation Risk Assessment (NGRA) is a safety evaluation approach that incorporates emerging tools such as in vitro methods, computational models, and omics data to inform decision-making for human health and the environment, while aiming to reduce dependence on traditional animal testing. NGRA frameworks, while potentially generic in principle, must be tailored to the specific regulatory requirements and exposure contexts of different product sectors, including pharmaceuticals, industrial chemicals, agrochemicals, and cosmetics. Short-term mechanistic animal studies serve as a bridge between traditional long-term animal testing and new approach methodologies. From a technical standpoint, the generation, analysis, and interpretation of omics data have matured considerably, bringing regulatory acceptance within reach. Remaining challenges include standardizing bioinformatics pipelines, building confidence through validation against apical endpoints, and expanding training. Addressing these gaps through collaborative science and flexible regulatory frameworks will be key to realizing the full potential of omics-enabled hazard profiles to support NGRA.
About
- Frequency
- Sun
- Papers found
- 200
- RSS feed
- Subscribe