Toxicological Sciences最新文献

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.

In utero exposure to the synthetic estrogen diethylstilbestrol (DES) has been linked to developmental abnormalities and elevated breast cancer risk in adulthood in human and rodent models. Although the impact of DES on the mammary epithelium has been thoroughly investigated, its effect on the other cell types of the mammary gland remains understudied. Here, given that the mammary gland development is strongly associated with its microenvironment, we aimed to investigate how in utero DES exposure alters the mammary gland's stromal and immune function across key developmental stages. To achieve this aim, timed-pregnant rats were gavaged daily with DES or vehicle from gestation days 16 to 21, and female offspring mammary glands were analyzed at pre-puberty (postnatal day 21 [PND21]), puberty (PND46), and adulthood (PND90). We assessed morphological and extracellular matrix changes, performed transcriptomic cell-type enrichment analysis, measured cytokine expression, and quantified immune cell populations. DES-exposed mammary glands exhibited pronounced stromal remodeling, including increased collagen deposition and orientation by adulthood. Gene expression profiling indicated DES-induced stage-specific immune alterations: Immune cell signatures were enriched at PND21 and PND90 but diminished at PND46. Correspondingly, DES increased macrophage populations at PND21 while reducing T-lymphocyte numbers at PND46 and PND90. DES exposure also dysregulated inflammatory cytokine/chemokine expression in adult glands, suggesting a persistent inflammatory environment. In conclusion, in utero exposure to an estrogenic compound can reprogram mammary development, inducing long-term changes in the extracellular matrix and immune landscape. These disruptions to stromal-immune homeostasis may impair normal mammary morphogenesis and increase susceptibility to breast pathologies later in life.

Wildfires have surged in frequency and severity, and in 2022, they contributed to nearly 30% of the fine inhalable particulate matter (PM2.5) in the United States. Health effects from wildfire-induced wood smoke (WS) exposure include worsened pre-existing lung diseases and lung function, increased emergency room visits, and increased risk of premature death. Evidence suggests that males and females have unique responses to air pollutants, but sex-specific responses to WS remain understudied. To evaluate whether males and females differentially respond to WS, we analyzed induced sputum samples in humans following a controlled chamber exposure to WS. A total of 79 participants were exposed to 500 µg/m3 of WS for 2 h with intermittent exercise, and a subset of participants' samples were analyzed for cellularity and cytokine concentrations, and protein expression in the sputum supernatants. Cell differentials were compared between pre-, 6 h, and 24 h post-exposure, and proteomic and cytokine signatures were compared between pre- and 24 h post-exposure. A total of 368 proteins were significantly different in females, and 27 were significantly different in males post-exposure. Pathway analysis revealed inhibition of leukocyte extravasation signaling, phagosome formation, and macrophage nitric oxide and reactive oxygen species pathways in females versus males. Females had a lower percentage of iNOS+ and a higher percentage of CD301+ sputum macrophages versus males. Overall, this exploratory analysis suggests that in response to acute WS exposure, different pathways are affected in females compared with males. Future studies are needed to determine whether this confers an immune advantage and to understand the mechanisms of sex-specific WS-induced respiratory effects.

Zebrafish (Danio rerio) are an ideal system for understanding developmental toxicity as they display similar toxicity outcomes to other vertebrates. Further, many molecules have been tested for developmental toxicity in zebrafish, providing an opportunity for machine learning model development. We curated 1,345 small molecules from ToxCast, flame retardant compounds, per- and polyfluoroalkyl substances (PFAS), and industrial chemicals published by the Superfund Research Program (SRP). Following curation, we trained machine learning models on the zebrafish toxicity endpoints ANY_ = any effect including mortality, ANY_BUT_MORT = any effect excluding mortality, MORT = mortality, i.e. did the embryo die, EDEM = did an edema form, and CRAN = Craniofacial malformation. We demonstrated that these models were better than random when compared with shuffled data. We also fine-tuned the molecular SMILES encoder MolBART to predict on all zebrafish toxicity endpoints and found it generally matched the performance of classical machine learning models for ANY_BUT_MORT, CRAN, and EDEM endpoints. We present new toxicity data for Proteolysis Targeting Chimeras (PROTACs) in zebrafish and machine learning models for these data by fingerprinting different parts of the molecule individually, yielding predictive performance (AUROC 0.6 to 0.7). If we are to reduce animal testing with new approach methodologies like these zebrafish toxicity models they need to be able adapt to new molecular classes like PROTACs.

The mycotoxin deoxynivalenol (DON) is a widespread contaminant that threatens male reproductive health, though the systemic mechanisms involving the gut-testis axis remain incompletely understood. We employed a multi-omics approach-integrating transcriptomics, 16S rRNA sequencing, and serum metabolomics-in a mouse model to investigate these mechanisms. Oral exposure to DON (2 mg/kg/day for 2 weeks) induced testicular damage and disrupted the blood-testis barrier, marked by the downregulation of Occludin and GJA1, alongside the suppression of steroidogenesis-related genes and proteins, including StAR and CYP17A1. Concurrently, DON triggered gut microbiota dysbiosis, characterized by an increased abundance of Desulfovibrio and a decline in beneficial bacteria. Serum metabolomics further identified a significant depletion of key fatty acids and the cholesterol precursor 5-Alpha-Cholestanol. Crucially, fecal microbiota transplantation from DON-treated mice reproduced testicular damage and suppressed steroidogenesis in recipient animals, directly establishing the causal role of gut microbiota in DON-induced reproductive toxicity. These findings collectively demonstrate that DON impairs male reproductive function by inducing gut microbiota dysbiosis and associated metabolic alterations. This work advances our understanding of the gut-testis axis in toxicology and provides mechanistic insights for mitigating mycotoxin-induced reproductive dysfunction.

Environmental pollution negatively impacts respiratory health by damaging and reprogramming airway epithelial cells (AECs). CYP1B1 is one of the most highly induced genes in AECs exposed to combustion-derived air pollutants such as wood smoke particulate matter (WSPM) and plays dual roles in generating toxic reactive intermediates and in the detoxification of xenobiotics of diverse nature. However, the significance of CYP1B1 induction by AECs challenged with pollutants remains unclear. A comparison of BEAS-2B and CYP1B1-overexpressing BEAS-2B cells revealed that CYP1B1 overexpression reduced acute cytotoxicity and enhanced proliferation and migration following WSPM-induced injury in vitro. Conversely, inhibition of CYP1B1 in HBEC3-KT cells increased cytotoxicity and decreased proliferation. CYP1B1 inhibition in HBEC3-KT cells exacerbated endoplasmic reticulum stress (ERS), which promotes cell cycle arrest and cytotoxicity, while overexpression of CYP1B1 attenuated ERS. CYP1B1 Inhibition also enhanced the expression of mRNA for the NRF2 target genes NQO1 and HMOX1, and the pro-inflammatory cytokine IL8, whereas CYP1B1 overexpression downregulated mRNA expression for NQO1 and HMOX1. In vivo, Cyp1b1-deficient mice exhibited greater basal lung inflammation, but limited response to WSPM-treatment compared to wild-type mice. However, Cyp1b1-/- derived mouse tracheal epithelial cells (MTEC) treated with WSPM showed a more pronounced inflammatory response, characterized by exacerbated Cxcl1, Cxcl2, and Trpa1 mRNA expression compared to wild-type cells. In conclusion, CYP1B1 mitigates WSPM-induced damage to AECs by squelching ERS, oxidative stress, NRF2, and inflammatory signaling, thereby supporting cellular defense and repair. Additional interactions with CYP1A1 and TRP channels also suggest a broader role in AEC physiology.

Chronic kidney disease (CKD) affects ∼15% of U.S. adults and over 840 million people worldwide. Environmental contaminants, including pesticides and metals, are increasingly recognized as disease contributors, yet mechanisms and consequences of long-term, low-level mixture exposures remain poorly defined. Our prior work identified glyphosate and metals (cadmium, arsenic, lead, vanadium) in drinking water from agricultural regions with high CKD prevalence and showed that early-life co-exposures disrupt kidney development. Here, using adult zebrafish as a mechanistic model, we tested whether chronic, low-level exposure to glyphosate, metals, and their combination impairs kidney function and structure. We exposed zebrafish for 10 and 60 days to glyphosate (10 ppb), metals (2 ppb Cd, 4 ppb As, 5 ppb Pb, 15 V), or glyphosate + metals and evaluated low-molecular weight proteinuria, histopathology, metabolomics, mitochondrial function, mitochondrial copy number, and mitophagy in the kidney. Chronic exposure to glyphosate and metals produced distinct yet overlapping kidney toxicity signatures, including tubular injury, altered metabolism, and impaired mitochondrial function. Co-exposures generated the most severe effects, with mitochondrial beta oxidation, respiration, and mitophagy as sensitive targets. These findings demonstrate that glyphosate and metals at levels found in drinking water damage kidney function over time, with co-exposure worsening outcomes compared to individual chemicals. Our study identifies mitochondria-rich proximal tubules as critical targets of chronic glyphosate-metal exposure, providing mechanistic insight into how environmental contaminants contribute to CKD risk. This work advances understanding of disease etiology in environmental nephropathies and highlights environmental factors as important drivers of kidney health.

Thyroid hormones (THs) influence testis development, with early life hypothyroidism resulting in smaller testes. Developmental exposure to thyroperoxidase (TPO)-inhibiting drugs such as propylthiouracil (PTU) and methimazole (MMI) also impair testis development in rodents by reducing TH levels, leading to smaller testes in pups due to, for instance, disrupted Sertoli cell proliferation and maturation. Comparable effects are seen following exposure to the TPO-inhibiting pesticide amitrole, one of many environmental chemicals with TH-disrupting properties. Despite this phenotype, the molecular underpinnings of hypothyroid-induced testis effects are less clear, complicating mechanism-based chemical toxicity testing relying on alternative test methods and omics approaches. Here, we report on transcriptomics profiling of testes from hypothyroid rats induced by chemical exposures. Pregnant Sprague-Dawley rat dams were exposed by oral gavage to two doses of MMI (8 or 16 mg/kg body weight/day) or amitrole (25 or 50 mg/kg bw/day) from gestational day (GD) 7 to pup day (PD) 16, with BRB-seq performed for both life stages, specifically GD21 and PD16. Both MMI and amitrole caused significant changes to the testis transcriptome, seen particularly at PD16, with 313 differentially expressed genes (DEGs) defining a shared TH-mediated profile. Additionally, amitrole exposure resulted in a distinct profile of 1,517 DEGs, suggesting compound specific effects beyond TH disruption. This study underscores the potential sensitivity of transcriptomic profiling in detecting early tissue disruption under toxicological conditions, in this case testis disruption under hypothyroid state, offering critical insights for chemical risk assessment beyond histopathological endpoints.

Exposure to environmental pollutants during key stages of development increases the risk of disease later in life. One such toxicant with growing evidence of this response is the air pollutant, ozone (O3). Exposure to O3 during the implantation receptivity period in rats affects the metabolic status of offspring at adolescence, which may increase their susceptibility to subsequent environmental exposures. Herein, we studied the impacts of maternal O3 exposure on postnatal systemic responses to O3 in male and female offspring. Following peri-implantation O3 exposure (0.8 ppm for 4 hours/day on gestation days 5 and 6), offspring were exposed to O3 for 1 day/week on postnatal weeks 5-7. After the final exposure, metabolic effects were analyzed by circulating hormones and clinical chemistries, as well as hepatic lipid status and transcriptomic alterations. By and large, male offspring from O3-exposed dams were more greatly impacted than those from air-exposed dams. This included increased hepatic lipid mobilization, increased circulating glucose, and a robust number of differentially expressed genes (2,348). Interestingly, many of these transcriptomic differences were attributed to maternal O3 exposure, with 1,741 of these genes sharing directional similarity with postnatally exposed air littermates. Females, on the other hand, reported minimal baseline effects of maternal O3 exposure (108). However, postnatal O3 exposure in female offspring substantially increased these differences to 947 genes. Collectively, this work supports the growing evidence that early pregnancy exposure to O3 alters the metabolic development of the offspring. Furthermore, postnatal exposure to environmental stressors reveals hepatic susceptibilities that are sexually dimorphic.