Ecotoxicology and Environmental Safety

Mitochondrial ploidy -- the relative copy number of mitochondrial DNA per mitochondrion -- may serve as an early marker of cellular stress and a potential signal of genotoxic damage. In this study, we investigate the dynamics of mitochondrial ploidy in iPSC cells in vitro following exposure to a range of chemical mutagens. Using a qPCR-based method allowing accurate quantification of mitochondrial DNA and mitochondria number, we reveal distinct changes in mitochondrial ploidy that correlate with the genotoxic impact of specific agents. Among the mutagens tested, MX, benzidine, cyclophosphamide, hydrogen peroxide, semustine and nickel (II) chloride induced the most pronounced alterations in mitochondrial DNA content and organization. These findings suggest that mitochondrial ploidy can be used as a sensitive molecular indicator of mutagenic stress, potentially reflecting mitochondrial genome maintenance and organelle adaptation mechanisms.

Polychlorinated biphenyls (PCBs) are ubiquitous and representative pollutants that pose great health risks. While cells responses to dioxin-like PCBs tend to be studied on a bulk scale, few studies have been made from a single-cell level. Here, by using single-cell RNA sequencing, we depicted a detailed landscape of hepatic nonparenchymal cells intricate responses to PCB126 exposure. A total of 13 clusters were identified. Notably, PCB126 exposure resulted in cell-type-specific gene expression profiles and genetic pathways. By analyzing genes related to aryl hydrocarbon receptors, we discovered that PCB126 induced the canonical genomic AhR pathway mainly in endothelial cells. In contrast, other cell types showed little induction. Enrichment pathway analysis indicated that immune cells changed their transcriptional patterns in response to PCB126. ScRNA-seq is a powerful tool to dissect underlying mechanisms of chemical toxicity regarding biological heterogeneity. Taken together, our study not only extends our current understanding of PCB126 toxicity, but also emphasizes the importance of in vivo cell heterogeneity in environmental toxicology.

Exposure to chemical pollutants can alter the rate, and genome-wide distribution of germline mutations. However, studies measuring the effect of chemical exposure on mutation rate and spectra have not considered the ecological and evolutionary backgrounds of studied genotypes, which could influence the rates and patterns of germline mutations in altered environments, e.g., chemical pollution. Utilizing a study of natural Daphnia pulex populations, we conducted a comprehensive experiment to test our hypothesis that adaptation to chemical pollution also protects the germline from mutagenesis. We, 1) identified Daphnia pulex populations that have adapted to live in mining-devastated regions by increasing their cadmium tolerance. 2) We completed a mutation-accumulation (MA) experiment with an adapted genotype to measure the germline mutation rate in both control conditions and an environmentally relevant cadmium concentration. 3) We compared these MA experiment results to a previously reported, identically designed MA experiment with a nonadapted genotype. We report that patterns of cadmium-induced mutagenesis in the adapted genotype were reversed compared to our previous observations in the nonadapted genotype. Cadmium exposure altered the single nucleotide mutation (SNM) rate in the same genome regions in adapted and nonadapted genotypes, but the rates were changed in opposite directions. Cadmium also altered specific SNM classes in these genotypes in opposite directions. The reversal of mutational trends in the adapted genotype suggests protection against cadmium genotoxicity. We further demonstrate that adapted populations have elevated gene copy-number and expression levels of metallothionein, the protein that protects against cadmium toxicity by binding to cadmium irreversibly.

While distinct environmental exposures imprint unique mutational signatures on cancer genomes, the specific causal patterns for many known carcinogens remain uncharacterized in relevant human tissues. To address this gap, we developed a novel, physiologically relevant system that uses a combination of airway epithelial cells and whole genome sequencing to characterize mutational patterns induced by genotoxic carcinogens associated with lung cancer. After validating the platforms accuracy by successfully recapturing the known signature for Benzo(a)pyrene (BaP), we used this system to gain detailed insights into the types of mutations that occur with exposure to N-nitrosotris-(2-chloroethyl) urea (NTCU) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), genotoxic compounds that induce lung squamous cell carcinoma and lung adenocarcinoma in mouse models, respectively. Cells exposed to NTCU had significantly more somatic SNVs compared to control samples. An average of 82.3% of mutations in NTCU samples were attributed to a novel mutational signature distinct from those in the COSMIC database but highly correlated with recent in vivo mouse models. In contrast, NNK exposure did not demonstrate a distinct mutational pattern above background at both high and low concentrations. Ultimately, this in vitro system provides a robust platform to define causal links between environmental exposures and mutational patterns in lung cancer mutagenesis. Statement of SignificanceIn vitro exposure of N-nitrosotris-(2-chloroethyl) urea to airway epithelial cells revealed a distinct mutational signature.

Chronic contaminant exposure may impose hidden physiological costs long before obvious demographic or health effects become detectable in wildlife populations. Epigenetic clocks quantify biological ageing and may provide sensitive biomarkers of cumulative toxicological stress. Per-and polyfluoroalkyl substances (PFAS) are persistent contaminants that bioaccumulate in marine food webs, yet their long-term physiological consequences for wildlife remain poorly understood. Here, we tested whether PFAS exposure is associated with accelerated biological ageing in common dolphins (Delphinus delphis). We analysed liver PFAS concentrations and skin DNA methylation profiles from 30 stranded or bycaught dolphins from New Zealand waters. Epigenetic age was estimated using a recently developed species-specific epigenetic clock, and age acceleration was calculated as the residual deviation between epigenetic and chronological age. Using an information-theoretic modelling framework, we assessed the effects of total PFAS burden, sex, and their interactions on epigenetic age acceleration. Total PFAS concentrations were positively associated with epigenetic age acceleration, indicating that dolphins with higher PFAS burdens were biologically older than expected for their chronological age. Each 1 ng g{square}{superscript 1} increase in total PFAS was associated with an average increase of 0.031 years in biological age. Sex did not significantly influence age acceleration, suggesting that PFAS-associated ageing effects occur across both sexes. Although modest, this effect is consistent with PFAS acting as a chronic physiological stressor influencing molecular ageing processes. Our findings provide the first evidence linking PFAS exposure to accelerated biological ageing in a wild mammal, highlighting epigenetic ageing as an integrative biomarker of long-term contaminant effects in wildlife.

BackgroundMicro- and nanoplastics (MNPs) contamination may pose a significant risk to human health. However, their true impact remains underexplored due to substantial limitations of current analytical methods. Traditional techniques like Raman and FTIR microscopy, coupled with filtration, fail to detect smaller MNPs and are prone to external contamination. Likewise, pyrolysis-GC/MS lacks the ability to pinpoint MNP size or location. MethodsThis study presents a universal approach for MNPs detection in tissues, validated to mitigate external contamination risks and enable the identification of significantly smaller MNPs. The method preserves histological information, allowing for comprehensive spatial analysis, including assesment of local DNA damage using the {gamma}-H2AX histone. FindingsApplying this method to human placenta samples revealed orders of magnitude higher MNP loads than previously reported, with quantities ranging from thousands to millions per cm3, far exceeding current reports of fewer than 1 MNP per gram or cm3 of tissue. Importantly, within the observed concentration range, we found a positive association between MNP load and placental DNA damage. InterpretationOur findings show that that the prevalence of MNPs in biological tissues has been substantially underestimated, as the smallest and potentially most harmful MNPs go undetected with traditional methods. Furthermore, we found that the concentations were linked with genotoxic effects in the placenta. This novel analytical workflow represents a significant advancement in MNPs research and provides crucial insights into their impact on human health. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSPrior to our study, MNPs have been detected in human tissues, including the placenta, but in very low quantities, often fewer than 1 MNP per gram or cm3 (Amereh et al., 2022; Ragusa et al., 2021). Current detection methods, such as Raman and FTIR microscopy, have significant challenges, particularly in detecting MNPs in the lower size range, which are considered more hazardous (Dzier[z]y[n]ski et al., 2024). These methods also involve lengthy sample preparation processes, including chemical dissolution and filtration, which inherently lead to the loss of histological information. Additionally, they carry a high risk of external sample contamination, as well as MNP degradation and alteration, compromising the accuracy and reliability of the results (Renner et al., 2018). Added value of this studyThis study introduces a universal analytical workflow for MNPs detection in tissues that addresses critical limitations of existing methods. By eliminating external contamination risks and enabling the detection of significantly smaller MNPs, this method revealed orders of magnitude higher MNPs loads in human placenta samples compared to previous reports. The preservation of histological information allows for detailed spatial mapping of MNPs, contributing to a more comprehensive understanding of their distribution and potential biological impacts. A key finding of this study is the positive association between MNP load and placental DNA damage, as quantified by {gamma}-H2AX labeling. This direct correlation between MNP exposure and genotoxic effects strongly suggests that the observed DNA damage is not an artifact of external contamination but rather a consequence of internalized MNPs within the tissue. This first finding of the presence of {gamma}-H2AX foci, a well-established biomarker of DNA double-strand breaks, underscores the potential genotoxic risk posed by MNPs and highlights their ability to induce cellular harm at the molecular level. Implications of all the available evidenceOur research indicates that the true MNPs load in human tissues may be significantly higher than previously recognized. The analytical workflow presented here has the potential to transform the field of MNPs research by enabling more accurate assessments of MNP prevalence in human and other biological tissues. Designed with methods and techniques widely available to researchers across disciplines, this workflow can be readily applied to diverse biological and environmental studies. This, in turn, could inform future studies on their biological interactions, long-term health effects, and dose-response relationships. Given the widespread presence of MNPs in the environment, our findings underscore the urgent need for longitudinal studies to evaluate the chronic effects of exposure, particularly in vulnerable populations such as pregnant individuals and their developing fetuses. Additionally, our findings and methodology are a stepping stone towards true direct toxicological research on MNPs. Addressing MNP contamination at the source and improving public and regulatory awareness are critical steps toward developing effective mitigation strategies.

In vitro toxicology has used immortalized cancer cell lines as model human systems for decades. However, these cell lines pose problems in designing toxicity testing programs as they inherently do not represent normal human biology. There is also a huge number of such cell lines to choose from, derived from human cancer cells from nearly every tissue. We explored the idea of using available basal gene expression data (NCI-60 cell line panel and Human GTEx tissue data) to determine if there was sufficient variability in cell line gene expression to group cell lines by relevance to specific human tissues. The transcriptomic analysis suggests that the variability in gene expression in cancer cell lines and in normal human tissue is minimal. The overall basal gene expression of cancer cells lines even overlapped normal human tissue gene expression. While some human tissues (e.g., lung) have basal expression profiles that do not appear to be like any cancer cell line, including cancers that may be derived from the same tissue, most human tissues show basal expression profiles comparable to several cancer cell lines. These results are important to address the genomic baseline and variability of cancer cell lines used for new approach methods of toxicity testing.

There are substantial gaps in our empirical knowledge of the effects of chemical exposure on aquatic life that are unlikely to be filled by traditional laboratory toxicity testing alone. One possible alternative of generating new toxicity data is cross-species extrapolation (CSE), a statistical approach in which existing data are used to predict the effect of a chemical on untested species. Some CSE models use relatedness as a predictor of chemical sensitivity, but relatively little is known about how strongly shared evolutionary history influences sensitivity across all chemicals. To address this question, we conducted a survey of phylogenetic signal in the toxicity data from aquatic animal species for a large set of chemicals using a phylogeny inferred from taxonomy. Strong phylogenetic signal was present in just six of thirty-two toxicity datasets, and there were no clear shared properties among those datasets with strong signal. Strong signal was rare even among chemicals specifically developed to target insects, meaning that these chemicals may be equally lethal to non-target taxa, including chordates. When signal was strong, distinct patterns of sensitivity were evident in the data, which may be informative when assembling toxicity datasets for regulatory use. Although strong signal does not appear to manifest in aquatic toxicity data for most chemicals, we encourage additional phylogenetic evaluations of toxicity data in order to guide the selection of CSE tools and as a means to explore the patterns of chemical sensitivity across the broad diversity of life.

BackgroundAir pollution caused by fine particles has been recognized as a significant environmental risk factor. Over the past two decades, there has been a substantial increase in evidence on the impact of air pollutants on mortality and morbidity in vulnerable groups, such as children under 5 years of age, people over 60 years of age, and people with comorbidities, primarily in low- and middle-income countries. However, most studies have focused on nosologically identified respiratory and cardiovascular events. Our objective was to evaluate the relationship between PM2.5 ambient air pollution exposure and -physical fitness (PF), an attribute that determines an individua[l]s physical performance and general health, in adults from Medellin, Colombia. MethodsA cross-sectional nested cohort study was conducted to establish exposure to PM2.5 by each participants residence address. Physical fitness was assessed using the Dundee step test, sit-to-stand muscle power test, and grip strength. Multiple linear regression models adjusted for personal medical history were constructed to evaluate the study relationship. Results320 participants were included, with an average age of 60 {+/-} 8.7 years and an annual PM2.5 ambient air pollution of 18.9 {+/-} 1.75 {micro}g/m3. People with PM2.5 exposures above the 75th percentile showed greater use of the heart rate reserve ({beta} coefficient= 7.11; 95%CI 1.11-13.12) and better relative muscle power ({beta} coefficient= 0.50; 95%CI 0.23). -0.77) and grip strength ({beta} coefficient= 3.59; 95%CI 1.63-5.56). ConclusionsThis is the first study to explore the relationship between ambient PM2.5 ambient air pollution and cardiorespiratory and muscular fitness in a Latin American city. Our results indicate that people with greater exposure to PM2.5 have worse cardiorespiratory fitness (CRF) and better muscular fitness (MF). Key pointsPhysical fitness determines an individuals physical performance and general health status and includes indicators for establishing a cardiovascular baseline. Prolonged exposure to air pollution negatively affects cardiovascular health. However, few studies have analyzed physical fitness indicators in relation to this environmental risk factor, and none have been conducted in the Latin American population. It was established that people with higher exposure to PM2.5 ambient air pollution at their residence address had worse cardiorespiratory fitness.

We measured baseline levels of 19 trace element and mercury speciation for grey seals (Halichoerus grypus) from the Gulf of St. Lawrence (GSL), Quebec, Canada. With interest growing in commercializing grey seal products for human consumption in this region, the goal of this study was to measure essential and non-essential trace elements in grey seals to evaluate health concerns and nutritional benefits. From 2015 to 2019, 120 grey seals were sampled by hunters and researchers at 4 sites in the GSL. Muscle, liver, heart and kidney samples were analyzed for 10 non-essential elements (Sb, As, Be, B, Cd, Pb, Hg, Ni, Tl, Sn) and 9 essential elements (Co, Cr, Cu, Fe, Mg, Mn, Mo, Se, Zn). Both total mercury (THg) and methylmercury (MeHg) were analysed for a subset of samples. Many elements were undetected in liver (Sb, As, Be, B, Cr, Co, Pb, Ni, Tl, Sn) and muscle tissues (same, plus Cd, Mn, Mo). Results showed lower element concentrations in the muscle (Fe, Mg, Se) and livers (Cd, Cr, Hg, Mn, Mo, Se) of young-of-the-year harvested in the winter (< 6 weeks old) compared to older animals feeding at sea. For older seals ([~] 5 months to 29 years), we did not observe progressive age-dependent bioaccumulation. Sex-specific differences were not very pronounced, but a few elements were 30 - 70% higher in the muscle (THg, MeHg) and liver (Mn, Zn) of male seals. Comparison to Canadian dietary reference intakes shows that a weekly portion of liver from young-of-the-year (< 6 weeks old) is a good source of essential elements (Cu, Fe) and that muscle and liver from this age category does not exceed reference values for toxic elements (As, Cd, Pb, MeHg). Ongoing discussions with regional public health professionals will help to develop dietary recommendations for the consumption of older grey seals. HIGHLIGHTSO_LIWe measured baseline levels of 19 trace elements in grey seals harvested from the Gulf of St. Lawrence. C_LIO_LIWe evaluated nutritional benefits and health concerns of human consumption of grey seal products. C_LIO_LIOnce seals began feeding at sea ([~] 5 mo), many element concentrations increased, but did not bioaccumulate progressively with age afterwards. C_LIO_LISome elements were more concentrated in the muscle (mercury) and livers (manganese, zinc) of male seals. C_LIO_LIYoung seal (< 6 we) livers are a good dietary sources of copper and iron, while its muscle and liver were below reference values for toxic elements. C_LI GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=105 SRC="FIGDIR/small/458200v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@ad9ea6org.highwire.dtl.DTLVardef@8adf1borg.highwire.dtl.DTLVardef@13d992eorg.highwire.dtl.DTLVardef@113c8c7_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioRxiv has withdrawn this preprint because we no longer have confidence on the validity of the manuscript and the identity of the authors. Therefore, this work should not be cited as a reference for this project.

Over 100,000 people were exposed to arsenic-contaminated drinking water in Antofagasta, Chile from 1958-1970. Individuals born during this high exposure period have elevated rates of cancer, lung and cardiovascular disease, and hypertension. However, the mechanisms of long-term arsenic toxicity remain unclear. We investigated whether early-life arsenic exposure was associated with altered glucocorticoid levels in adulthood. This study included 114 individuals born in Antofagasta during the high exposure period and 118 individuals born elsewhere. Arsenic exposure metrics were constructed based on residential histories and included: concentration at birth, peak and highest 5-year average between ages 0-10 years, and highest lifetime 5-year average, and lifetime cumulative exposure. Morning plasma cortisol concentrations were measured using a cell-based bioassay. Individuals in the highest quartile of highest lifetime 5-year average of arsenic exposure had approximately 11% lower mean log cortisol levels than those in the lowest quartile of exposure ({beta} = -0.116; 95% CI: -0.229, -0.003). In sex-stratified analyses, associations were stronger among females. For example, females in the highest quartile of cumulative exposure had 22.0% lower cortisol levels compared to those in the lowest quartile ({beta} = -0.248; 95% CI: -0.444, -0.053) and the test for interaction by sex was statistically significant (p = 0.036). This study is the first to show that early-life arsenic exposure may have lasting effects on cortisol. These findings highlight endocrine disruption as a mechanism contributing to long-term health effects of early arsenic exposure.

Quantitative Adverse Outcome Pathways (qAOPs) may support next-generation risk assessment by integrating New Approach Methodologies (NAMs) for derivation of points of departure. To be useful, a qAOP should be chemical-agnostic. However, existing qAOP studies often pool multi-chemical data without adequately addressing inter-chemical heterogeneity. Consequently, fundamental pathway relationships become obscured by heterogeneity-induced noise, thereby compromising the reliability of chemical-agnostic predictions. We developed a chemical-agnostic calibration approach to addresses this challenge by leveraging hierarchical structures to systematically separate chemical-specific heterogeneity from underlying pathway effects. Through this methodological framework, chemical-specific deviations are explicitly modeled as random effects, enabling the extraction of pathway-level parameters that represent core mechanistic relationships independent of individual chemical properties. Through simulation studies across varying heterogeneity levels, we demonstrate that performance differences between models with and without hierarchical calibration reveal the magnitude of heterogeneity in the data. Moreover, when heterogeneity is substantial, an uncalibrated qAOP should not be considered truly chemical-agnostic in practice, as it confounds pathway-level effects with chemical-specific variation. We demonstrated the application of this calibration approach through a case study of non-mutagenic liver tumor. The framework proposed in this study enhances qAOP generalizability while preserving the chemical-agnostic principle, supporting robust NAMs-based next-generation risk assessments. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=89 SRC="FIGDIR/small/642550v2_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@e7011eorg.highwire.dtl.DTLVardef@1fa7be9org.highwire.dtl.DTLVardef@1dd0b52org.highwire.dtl.DTLVardef@1123a93_HPS_FORMAT_FIGEXP M_FIG Figure 1: For TOC only C_FIG

Background: Men with prostate cancer (PCa) may be especially vulnerable to per- and polyfluoroalkyl substances (PFAS) exposure due to their endocrine-disrupting and cardiometabolic impacts and cardiotoxicity and immune suppression of treatments. Objective: A pilot study was launched to measure serum and tap water PFAS concentrations in PCa survivors. Methods: Men with PCa were recruited from Rutgers Cancer Institute between February 2025 and March 2026, with ongoing enrollment and follow-up. Eligible men were aged [&ge;]40 years and either on active surveillance or within 3-12 months of initial definitive treatment. Participants provided blood and residential tap water samples, which were analyzed using mass spectrometry (serum) and modified EPA method 537 (water). Geometric means were used to summarize PFAS concentrations by race and assess serum-tap water correlations. Results: Of 235 eligible patients, 124 (60%) enrolled. Median age was 64 years; 63% were non-Hispanic White, 43% had a Gleason score [&le;]6. Roughly half of participants provided serum and/or tap water samples. In serum, six PFAS analytes had >80% detection; of these analytes, median concentrations ranged from 0.13 ng/mL (IQR: 0.07-0.20) for PFHpS to 2.55 ng/mL (IQR:1.54-3.82) for nPFOS. Among 74 tap water samples, 9 PFAS analytes had >60% detection; of these, median concentrations of PFNA (0.56 ng/L; IQR: 0.33-0.75), PFOA (3.75 ng/L; IQR: 1.21-5.27), and PFOS (2.29 ng/L; IQR: 0.46-2.89), were below New Jersey Maximum Contaminant Levels. Non-White participants had significantly higher levels of multiple PFAS analytes in both serum and tap water. Serum-tap water correlations were modest (r=0.22-0.41). Significance: The pilot study has demonstrated both the feasibility and importance of studying PFAS exposure pathways as well as potential impacts of PFAS exposure in diverse populations. Keywords: Prostatic Neoplasms, Per- and Polyfluoroalkyl Substances (PFAS), Biomonitoring, Environmental Exposure, Cohort Studies, Pilot study Impact Statement: This study provides some of the first estimates of PFAS exposure among prostate cancer patients in serum and tap water, showing moderate correlations between tap water and serum concentrations of specific PFAS analytes. These findings can support larger studies to identify environmental exposure sources and evaluate the role of PFAS in prostate cancer progression and outcomes.

High metabolic rate may provide fitness benefits for individuals. But high metabolic rates incur energetic costs and the need to ingest more food, increasing the risks of ingesting harmful substances from the environment. How organisms respond to elevated levels of ionizing radiation is an important question in the light of increasing pollution from nuclear accidents and waste, as well as ever-increasing reliance on radiation in medical diagnostics and therapies. We investigated how limits to metabolic rate, and aerobic metabolic scope (ceiling of energetic activity above maintenance levels), of wild rodents inhabiting a gradient of radioactive contamination from the Chernobyl accident covary with the biological burden of radionuclides in their bodies. Our results demonstrate that high biological dose rate correlates with high self-maintenance and low aerobic capacity in adults. In contrast, in subadults high dose rate correlates with high aerobic capacity. Consequently, high dose rate correlates with low aerobic scope in adults, but with high aerobic scope in subadults. Despite the uncertainty of the causal mechanisms, whether the dose rate affects the metabolic rate, the reverse or the reciprocal feedback prevail, it can be hypothesized that metabolic down-regulation could contribute to protection against radioactive exposure. Yet, metabolic down-regulation might be constrained by developmental obligations. Understanding the physiological mechanisms affecting responses to radiation exposure is key for risk assessment of environmental contamination, radiotherapies, and space exploration, and may help to rectify discordant opinions concerning the effects of radiation on the ecology of organisms living in Chornobyl.

Pollution is a significant threat to aquatic ecosystems globally and, in order to survive, natural populations depend upon their ability to rapidly develop tolerance to chemical stressors. We examined whether early-life priming enhances life-long copper-tolerance in a model fish species via developmental plasticity. Stickleback (Gasterosteus aculeatus) embryos were pre-exposed to a low concentration of copper (10 {micro}g/L) during early development, reared in clean water for nine months alongside a control group, and then exposed to copper (0,10 and 20 {micro}g/L) for 96 h as adults. Priming markedly reduced evidence of copper-toxicity in adult gills at the transcriptional level (including reduced cellular stress response (CSR) and disruption of ion-homeostasis) and increased inducibility of the metal-binding protein, metallothionein. In parallel, we identified epigenetic and microbiome-mediated mechanisms likely contributing to this tolerance. Pre-exposure induced persistent DNA methylation changes, consistent with priming of CSR and ion-homeostasis pathways. We identified enhanced copper-tolerance in the gill microbiota of primed fish that likely also contributed to host tolerance. These findings provide critical evidence for developmental plasticity induced by chemical stressors in animals, highlight the importance of integrated microbiome and epigenetic responses, and enhance our understanding of how natural populations cope with pollution in their environment.

MotivationThe Adverse Outcome Pathways (AOP) framework advances alternative toxicology by prioritizing the mechanisms underlying toxic effects. It organizes existing knowledge in a structured way, tracing the progression from the initial perturbation of a molecular event--caused by various stressors--through key events (KEs) across different biological levels, ultimately leading to adverse outcomes that affect human health and ecosystems. However, the increasing volume of toxicological data presents a significant challenge for integrating all available knowledge effectively. ResultsArtificial intelligence provides powerful methods to analyze and integrate large, heterogeneous data sources. Within this framework, the AOP-helpFinder text mining tool, accessible as a web server, was designed to identify stressor-event and event-event relationships by automatically screening scientific literature in the PubMed database, facilitating the development of AOPs. The proposed new version introduces enhanced functionality by incorporating additional data sources, automatically annotating events from the literature with toxicological database information in a systems biology context. Users can now visualize results as interactive networks directly on the web server. With these advancements, AOP-helpFinder 3.0 offers a robust solution for integrative and predictive toxicology, as demonstrated in a case study exploring toxicological mechanisms associated with radon exposure. AvailabilityAOP-helpFinder is available at https://aop-helpfinder-v3.u-paris-sciences.fr/ Contactkarine.audouze@u-paris.fr Supplementary informationSupplementary data are available on Zenodo (https://zenodo.org/records/15193936) and codes on GitHub (https://github.com/systox1124/AOP-helpFinder).

Fine particulate matter (PM2.5) was found to be associated with elevated blood lipids, but fewer studies have examined the associations with specific constituents of PM2.5. We studied the associations between exposure to annual PM2.5 and its 14 constituents, and repeated blood lipid measurements among general responders enrolled in the World Trade Center Health Program between 2003 and 2019 (n = 44,876). We used generalized additive mixed effect models to investigate the single-pollutant associations with repeated measures of blood total cholesterol (TC), high and low-density lipoprotein (HDL-C and LDL-C) levels. We then used linear generalized weighted quantile sum regression with a random intercept for participant ID to account for the clustering of repeated measures and evaluate the combined associations with the component mixture. A decile increase in the mixture of 14 PM2.5 chemical components was associated with 0.375 mg/dL increase in TC levels (95% confidence Interval (CI): 0.174-0.577) and 0.302 mg/dL increase in LDL-C (95% CI: 0.063, 0.540). Lead, organic carbon, and iron were major drivers of both associations. Component-specific models also show higher TC and LDL levels associated with interquartile range increases in organic carbon (0.472, 95% CI [0.027, 0.918] and 0.648 95% CI [0.136, 1.160]) and iron exposure (1.081, 95% CI [0.630, 1.532] and 0.748, 95% CI [0.318, 1.178]). In conclusion, we found PM2.5 exposure to be associated with elevated lipid levels. The associations differed by PM2.5 composition, highlighting organic carbon, lead, and iron and major drivers. These findings are highly significant for a population exposed to extreme air pollution event and susceptible to lipid alterations that might trigger cardiovascular events.

BackgroundAir pollution has been recognized as an untraditional risk factor for myocardial infarction (MI). However, the MI risk attributable to long-term exposure to fine particulate matter (PM2.5) is unclear, especially in younger populations, and few studies represented the general population. MethodsWe applied the difference-in-differences approach to estimate the relationship between annual PM2.5 exposure and hospitalizations for MI among U.S. residents and further identified potential susceptible subpopulations. All hospital admissions for MI in ten U.S. states over the period 2002-2016 were obtained from the Healthcare Cost and Utilization Project State Inpatient Database. ResultsIn total, 1,914,684 MI hospital admissions from 8,106 ZIP codes in ten states from 2002 to 2016 were included in this study. We observed a 1.35% (95% CI: 1.11-1.59%) increase in MI hospitalization rate for 1 g/m3 increase in annual PM2.5 exposure. The estimate was robust to adjustment for surface pressure, relative humidity and co-pollutants. In the population with exposure at or below 12 g/m3, there was a larger increment of 2.17% (95% CI: 1.79-2.56%) in hospitalization rate associated with 1 g/m3 increase in PM2.5. Young people (0-34 years) and elderly people ([&ge;]75 years) were the two most susceptible age groups. Residents living in more densely populated or poorer areas and individuals with comorbidities were observed to be at a greater risk. ConclusionsThis study indicates long-term residential exposure to PM2.5 could lead to increased risk of MI among U.S. general population. The association persists below current standards. Clinical PerspectiveO_ST_ABSWhat is new?C_ST_ABSO_LILong-term exposure to PM2.5 increased the risk of myocardial infarction in the general U.S. population. C_LIO_LIYoung individuals aged 0-34 years had the highest relative risk from long-term exposure to PM2.5, and elderly people aged [&ge;]75 years were the second most susceptible to the effects. C_LIO_LIIndividuals with iron deficiency anemia, psychosis, and renal failure were more susceptible to the long-term effects of PM2.5 on MI. C_LI What are the clinical implications?O_LILong-term PM2.5 exposure is one of the important modifiable environmental risk factors for myocardial infarction, therefore, air pollution control and behavioral interventions should be taken to prevent the occurrence of myocardial infarction. C_LI

Lead (Pb), chromium (Cr), and cadmium (Cd) are heavy metals that contaminate sites throughout North America. Historically, toxicological effects of Pb, Cr, or Cd compounds have been investigated in a hybrid mouse strain, B6C3F1. However, humans have more genetic diversity and population variability in response to toxicants than is represented in this homogeneous mouse model, which leaves genetic effects on dose response uncertain. Use of the Collaborative Cross (CC) addresses the problem of limited genetic diversity inherent in models like B6C3F1. In previous work, blood Pb levels in panel of female CC lines exposed to high-dose (0.1%) lead acetate showed a strain dependent response. Four strains from the original study with varying Pb blood levels after exposure were selected to determine if strain and sex dependence was exhibited in a two-week acute exposure to Pb, but also to Cr or Cd exposure. To investigate genetic background influence on metal deposition, five animals of each sex from each strain were placed on an American diet for one week prior to dosing high- (0.1%) or low- (0.01%) dose Pb acetate, high- (0.1%) or low- (0.01%) sodium dichromate, or high- (0.1%) or low- (0.01%) cadmium chloride via drinking water ad libitum for 14-days, matching the standard short-term exposure of the National Toxicology Program. Body composition was measured before the start of dosing and prior to necropsy using EcoMRI. Blood Pb at necropsy from this study suggests the strain dependent trends observed in previous exposures is conserved for acute Pb exposure but with different trends for Cr and Cd indicating that even a small panel of strains will not suffice for estimating variation across all toxicants.