Toxicological Sciences最新文献

Parental exposure to toxicants can affect progeny health. However, laboratory studies often employ exposures that result in loading of pollutants to gametes or toxic effects to parents, which could indirectly affect germ cell or gamete health. Here, we took advantage of the biology of Caenorhabditis elegans to carry out a study in which we minimized the potential for maternal loading of toxicants, and used an exposure paradigm that either did (high concentration) or did not (low concentration) significantly impact the health of the P0 generation. We hypothesized that parental exposure to mitochondrial toxicants during germ cell and gamete development, at levels not causing P0 toxicity, would result in altered mitochondria and organismal health in offspring. In the P0 generation, a high rotenone concentration altered growth, mitochondrial respiration, gene expression, induction of the mitochondrial unfolded protein response, and susceptibility to dopaminergic neurodegeneration induced by a chemical rechallenge later in life. However, we observed minor or no effects in P0 at a low concentration. In high-exposure F1 offspring, we observed altered embryo size, larval developmental stage distribution, spare respiratory capacity, heat shock protein expression, and dopaminergic neurodegeneration after a secondary rotenone challenge. The only effects observed in the F1 offspring of the low exposure were a 1.7% decrease in egg size (size later in development was normal), and moderate evidence of a slightly increased sensitivity to heat shock protein expression and dopaminergic neurodegeneration caused by a secondary later-in-life rotenone exposure. We recommend that parental toxicity be carefully assessed to contextualize offspring outcomes.

Volatile organic compounds (VOCs) are increasingly implicated in systemic diseases, but their contribution to skin disorders such as atopic dermatitis (AD) remains unclear. This study assessed VOC concentrations in medical environments, their effects on AD development, and the efficacy of VOC removal using chemical filters. Total VOC levels were monitored in 3 types of veterinary hospitals. AD-like lesions were induced in female NC/Nga mice by repeated dermal application of toluene diisocyanate or house dust mite ointment, with or without topical exposure to a VOC mixture (10 μg/ml). Clinical parameters, including dermatitis scores, transepidermal water loss, and skin thickness, were measured weekly, and immunological and histological analyses were performed. VOC monitoring revealed that 1 hospital exhibited concentrations exceeding 400 μg/m³. In the mouse model, direct VOC exposure significantly aggravated keratinocyte inflammation and worsened AD symptoms. Application of chemical filtering systems effectively reduced VOC levels in real clinical settings, and their use in the experimental model suppressed AD development. However, therapeutic application of VOC removal showed only limited effects on systemic immunological markers. These findings suggest that VOCs present in healthcare environments may contribute to the onset and progression of AD. Incorporating VOC-removing filters into air-conditioning systems could serve as a preventive strategy to improve the management of allergic skin diseases.

Firefighters are exposed to high levels of toxic chemicals while fighting fires, and previous studies have established these men and women have a significantly elevated risk for various cancers. Improved risk management for firefighters requires the identification of biomarkers indicative of physiological response. Micro-RNAs (miRNAs) have emerged as promising noninvasive prognostic and diagnostic biomarkers for various diseases. Here, we isolated miRNA from the urine of a large dataset of firefighters, collected pre- and post-fire exposure, as well as from healthy non-firefighter controls. miRNA was analyzed by microarray using the Affymetrix GeneChip miRNA 4.0 array. Analysis revealed 23 human miRNAs were significantly up-regulated and 25 significantly down-regulated in firefighters compared with control samples (analysis 1). Gene targets of these miRNAs were analyzed using the Online Database for Annotation, Visualization, and Integrated Discovery (DAVID) and found to cluster in several pathways and disease associations with smoking, cancer, and inflammatory diseases. Furthermore, we performed a longitudinal analysis of samples from firefighters that provided a sample prior to a fire exposure and immediately after a fire (analysis 2). This analysis found 20 miRNAs that were significantly up-regulated post-fire exposure. Of these, 5 were also up-regulated in firefighters vs control samples (hsa-miR-1268b, hsa-miR-4433b-3p, hsa-miR-4253, hsa-miR-6824-5p, and hsa-miR-3188). Again, analysis of gene targets of these miRNAs found association of mostly the same pathways and disease processes found in analysis 1. These findings are consistent with epidemiological evidence for increased risks associated with firefighting and offer a proof of concept and framework for the use of miRNA in urine as biomarkers for health risk assessment associated with firefighting.

In drug discovery, assessing cardiac contractile force is crucial because of its association with the development of cardiovascular events and heart failure. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) provide a promising in vitro model for drug discovery, particularly for assessing proarrhythmic risk. However, the availability of robust in vitro models to evaluate cardiac contractility has been limited. Here, we demonstrate that subjecting hiPSC-CMs to electrical stimulation for 48 h using a multielectrode array system induces partial functional and morphological maturation, as evidenced by a positive force-frequency relationship, increased conduction velocity of depolarization signals and improved sarcomere orientation with distinct Z-bands compared to unstimulated controls. We confirmed that electrical stimulation enables the evaluation of the positive inotropic effects of drug compounds with diverse pharmacological actions. The functional maturation induced by the electrical stimulation was observed across different facilities. The method also effectively detected prolonged QT intervals. These findings demonstrate the utility of the electrical stimulation for 48 h for hiPSC-CMs using the multielectrode array assay system to assess drug-induced contractile function and detect prolonged QT intervals in a single experiment, thereby enhancing the early-stage assessment of cardiotoxicity in drug discovery.

Exposure to agricultural chemicals is a risk factor for neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD). Chlorpyrifos (CPF) is an organophosphate insecticide widely used in agricultural and occupational settings. Epidemiological studies have associated CPF exposure with developmental impairments and an increased risk of AD and PD. Experimental characterization of the impact of chronic, systemic CPF exposure is essential for understanding how organophosphates actually influence disease risk. Multiple studies have assessed the effects of gestational exposure to CPF in preclinical models. To model exposure faced by adults, we administered CPF-contaminated drinking water to mice from 6 to 22 mo of age. This chronic exposure led to systemic effects, including reduced levels of the acute-phase protein haptoglobin (HTP) in both plasma and liver. Notably, the combination of aging and CPF exposure resulted in astrogliosis in the hippocampus and striatum, as well as neuronal loss in the striatum, primarily due to the loss of GAD65/67-immunoreactive interneurons. Having identified CPF-driven suppression of HPT in peripheral tissues, we examined HPT expression in brain tissues. We readily detected HPT expression in brain microglia. We then cultivated primary microglia and found that CPF exposure decreased HPT secretion in vitro. These findings indicate systemic and neurotoxic effects resulting from adult exposure to CPF-contaminated water.

Drug candidates are often evaluated for their activities against unexpected targets (off-targets), to either prospectively flag potential hazards or to provide mechanistic insights for a given phenotype. The in vitro to in vivo translatability is critical when selecting which "phenotypically consequential" off-targets to screen. To this end, human genetics and indication-based pharmacology offer unraveled insights. Enhanced natural language processing tools were applied to harness the power of large data obtained from 7 genetics and 2 pharmacology databases. Mapping biological roles to organ systems, we curated targets implicated in 22 organ systems of safety concerns, resulting in a safetyome composed of over ∼11,000 proteins. This is a significant expansion from our previously proposed screen, whose scope included phenotypes affecting 5 organ systems. Prioritization of the large panel using expression pattern and gene conservation across species resulted in a core panel of 500 targets. Mapping biological roles obtained from the databases to specific terms allowed us to systematically generate over 3,000 phenotype-based (specialized) panels, which can be used as gene or protein sets for issue resolution. All three components: The full safetyome, the core panel of 500 targets, and the over 3,000+ specialized panels, were systematically and orthogonally tested using independent data source, i.e., gene expression data from the Comparative Toxicogenomics Database. All panels, together with a user-friendly App, are published to aid effective safety assessment and issue resolution with strong "translational" focus.

Phthalates are ubiquitous endocrine-disrupting chemicals whose exposure is associated with accelerated reproductive aging in humans. We focused on the pituitary gland, the source of the gonadotropins: Follicle-stimulating hormone (FSH) and luteinizing hormone (LH). We hypothesized that the common phthalates di-(2-ethylhexyl) phthalate (DEHP) and diisononyl phthalate (DiNP) modulate inflammation in the pituitary and impact gonadotropin expression acutely and during aging. To test this, female CD-1 mice were orally dosed with corn oil or varying concentrations of DEHP and DiNP for 10 days. Pituitary tissues were collected immediately after dosing or 15 months post-dosing, processed, and analyzed by quantitative real-time PCR (qPCR) and immunohistochemistry. We found that acute phthalate exposure did not alter Fshb and Lhb mRNA expression compared with controls, but both DEHP and DiNP reduced FSH immunopositive cell number. Phthalate exposure also decreased Il1b, and increased Il18 and Tnf mRNA levels compared with controls, suggesting an inflammatory imbalance. At 15 months post-dosing, DiNP exposure increased Lhb and Il1b mRNA levels, but repressed Fshb and Nlrp3 mRNA levels compared with controls. Next, using dissociated cultures, we investigated the impact of phthalates and the proinflammatory stimulus lipopolysaccharide (LPS) on inflammation and gonadotropin gene expression directly at the pituitary. Both the DEHP metabolite MEHP and LPS decreased Fshb, but not Lhb mRNA relative to control. MEHP also repressed the induction of Il1b by LPS. Together, these findings suggest that acute exposure to phthalate alters mRNA expression of inflammatory markers and gonadotropins in the pituitary, which could alter the process of reproductive aging.

There is a critical need to understand pathophysiological mechanisms involved in injury from acute chlorine gas (Cl2) exposure. Limited information is available regarding the time course and mechanisms of injury after acute Cl2 exposure due to a lack of human clinical data and limited fidelity of pre-clinical animal models. We designed and integrated a Cl2 exposure platform to generate and deliver precise concentrations of Cl2 to a microfluidic human airway-on-a-chip microphysiological system. Chemical, biological, structural, and functional airway-on-a-chip responses to Cl2 exposure were characterized across multiple concentrations, exposure times, and post-exposure timepoints. Transcriptomics and metabolomics analyses delineated key molecular, cellular, and physiological pathways involved in the acute response to Cl2 exposure. This work represents a significant advancement towards high-throughput, human-relevant characterization of pulmonary toxicants and medical countermeasure development, addressing critical gaps in toxicology modeling while reducing reliance on animal studies.

Cupferron, widely used in industrial and analytical contexts, has been proposed as a potential nitric oxide (NO) donor; however, its effects on the male reproductive system remain unclear. We assessed toxicity in TM3 (Leydig) and TM4 (Sertoli) mouse cells. Cytotoxicity (6 to 0.0035 mg/ml) was measured by MTT/NRU; genotoxicity by comet assay; oxidative stress markers (MDA, 8-OHdG, GSH, SOD) and testosterone by ELISA; cell death and ROS by flow cytometry; and gene expression by RT-qPCR. MTT IC50 values were 0.131 mg/ml (TM3) and 0.219 mg/ml (TM4). At 0.125 mg/ml, comet assay revealed markedly increased DNA damage, ≥ 16-fold (P ≤ 0.05) in both TM3 and TM4 cells. In TM4, MDA and 8-OHdG rose ≥ 1.3-fold, while SOD activity increased in both TM3 (1.2-fold) and TM4 (1.5-fold) cells (P ≤ 0.05). Annexin V/PI analysis indicated increased necrosis without significant changes in apoptosis. Testosterone levels were unaffected at all doses. RT-qPCR showed upregulation of SOD1, HMOX1, GSTA1, GPX1 antioxidant genes in both TM3 and TM4 (P ≤ 0.05). Network toxicology highlighted NOS1, NOS3, and PTGS2 as putative targets, supported by docking indicating high affinity and substrate-like poses, implicating modulation of oxidative/inflammatory pathways. ADMETLab 3.0 predicted genotoxic, hepatotoxic, and carcinogenic risks. Overall, Cupferron induces oxidative stress, DNA damage, necrosis, and antioxidant gene activation in Leydig and Sertoli cells, supporting potential male reproductive toxicity and the need for comprehensive in vivo and mechanistic in vitro studies.