Archives of Toxicology最新文献

The rapid emergence of synthetic cannabinoid receptor agonists (SCRAs) poses challenges for drug testing, particularly when analyzing urine samples due to the rapid metabolization of the parent compounds. In early 2023, two novel SCRAs were reported to the European Union Drugs Agency (EUDA): ADMB-3TMS-PrINACA and Cumyl-3TMS-PrINACA, which are both indazole SCRAs featuring a trimethylsilyl propyl moiety connected to the tertiary indazole nitrogen. Peaks corresponding to metabolites of ADMB-BINACA (also known as ADB-BUTINACA) and Cumyl-4CN-BINACA observed with retention time shifts in a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detecting SCRAs were later identified as metabolites of ADMB- and Cumyl-3TMS-PrINACA. Pooled human liver microsome (pHLMs, 25 µmol/L) and pooled human hepatocyte (PHH, 20 µmol/L) assays were performed to generate metabolites. Additionally, human urine samples were analyzed by reversed phase liquid chromatography-quadrupole-time-of-flight-mass spectrometry (LC-QToF-MS), assisted by GLORYx and BioTransformer 3.0 for in silico metabolite prediction. Gas chromatography-mass spectrometry (GC-MS) was used to identify substances in seized materials. In total, 34 metabolites for ADMB-3TMS-PrINACA and 38 for Cumyl-3TMS-PrINACA were tentatively identified. Major biotransformations included side chain monohydroxylation (specific markers) and TMS-group cleavage, likely initiated by oxidative Si-demethylation followed by further hydroxylation resulting in an N-3-OH-propyl metabolite and further oxidation to the respective N-propionic acid. Most of these biomarkers were detected in the blood, urine, and stomach content of a deceased poly-drug user exposed to ADMB-3TMS-PrINACA. Overall, Cumyl-3TMS-PrINACA was more prevalent than ADMB-3TMS-PrINACA in Germany according to routine urine testing. This work provides the first investigation of the metabolic fate and suggests biomarkers for these new SCRAs.

This study investigated the role of ferroptosis in acute depleted uranium (DU)-induced nephrotoxicity. Using Sprague-Dawley rats and HK-2 cells to establish models of acute DU exposure (rats: 10 mg/kg; cells: 500 μM for 24 h), we found that DU exposure caused mitochondrial dysfunction, lipid peroxidation, and iron accumulation, all hallmarks of ferroptosis, which were inhibited by ferrostatin-1 (Fer-1). We identified mitochondrial ethylmalonic encephalopathy 1 (ETHE1) as a key DU target. ETHE1 downregulation exacerbated DU-induced reactive oxygen species (ROS), ferrous ions (Fe²⁺) overload and ferroptosis, while exogenous ETHE1 protein alleviated them. Furthermore, DU-triggered ROS activated the p38 mitogen-activated protein kinase (P38-MAPK) pathway, an effect enhanced by ETHE1 knockdown. Inhibiting P38-MAPK with adezmapimod (SB203580) suppressed ferroptosis and autophagy, and reduced the expression of nuclear receptor coactivator 4 (NCOA4), a mediator of ferritinophagy. Knockdown of NCOA4 also attenuated ferroptosis. In conclusion, acute DU exposure downregulates ETHE1, promoting mitochondrial ROS that activates P38-MAPK signaling. This pathway induces NCOA4-mediated ferritinophagy, ultimately leading to renal cell ferroptosis. These findings elucidate a novel mechanism for DU-induced kidney injury.

N, N-dimethylformamide (DMF), a widely used industrial solvent including new energy technologies, induces hepatotoxicity through poorly understood mechanisms. This study demonstrates that DMF exposure triggers ferroptosis in hepatocytes, characterized by glutathione depletion, iron accumulation, and lipid peroxidation both in vitro (0-160 mM DMF exposure) and in vivo (0, 750 mg/kg and 1500 mg/kg of DMF exposure). Transmission electron microscopy revealed ferroptotic mitochondrial damage, while biochemical assays confirmed GPX4 suppression and elevated 4-HNE levels. piRNA sequencing identified piR-16404 as significantly downregulated following DMF exposure. Functional studies showed piR-16404 overexpression attenuated DMF-induced ferroptosis by targeting CASTOR1, an arginine sensor for mTORC1. Mechanistically, piR-16404 binds CASTOR1's 3'-UTR to promote its degradation, thereby reactivating mTORC1-GPX4 signaling. In vivo supplementation of agomir-piR-16404 ameliorated DMF-induced liver injury, reducing serum ALT/AST by 42-58% and restoring hepatic GPX4 expression. Our findings establish ferroptosis as a key pathway in DMF hepatotoxicity and identify the piR-16404-CASTOR1-mTORC1 axis as a novel therapeutic target, providing new insights into environmental chemical-induced liver injury mechanisms.

The intestinal epithelium forms a selective barrier between the intestinal lumen and the subepithelial layer. Intestinal epithelium plays a critical role in initiating inflammatory tissue responses in vivo, which remains challenging to emulate in vitro. Caco-2 cells are commonly used models of the intestinal epithelium, but lack crucial receptors and pathways associated with pro-inflammatory reactions. Human-induced pluripotent stem cell (iPSC)-based in vitro models are assumed to provide a system that better emulates in vivo responses. This study evaluated the inflammatory response of iPSC-derived intestinal epithelial cells (IEC) and Caco-2-derived intestinal epithelial cells to the microbial toxins lipopolysaccharide (LPS) and nigericin. Here, iPSCs were differentiated towards enterocyte, goblet- and Paneth-like cells without using three-dimensional culture techniques. The formed monolayer barriers were exposed to a combination of 0-100 µM nigericin and 100 ng/mL LPS on either the apical or basolateral side. The treatment-induced expression of cytokine genes and cytokine secretion were compared between the iPSC-derived cell model and differentiated Caco-2 cell layers. Nigericin exposure in combination with LPS significantly reduced transepithelial electrical resistance in the iPSC-derived model, and resulted in a tenfold increased secretion of the pro-inflammatory cytokines interleukin (IL)-6, IL-8, and tumor necrosis factor-alpha compared to the negative control. A similar increase was observed for the mRNA expression of these cytokines. No significant effect on TEER, cytokine secretion, or mRNA expression was observed in the Caco-2 model. Overall, this study shows that iPSC-IECs are a more sensitive model compared to Caco-2 to emulate inflammatory perturbations of the human intestinal epithelium.

Microcystis, a commonly occurring genus of bloom-forming cyanobacteria, can produce numerous secondary metabolites, including microcystins (MCs), which are hepatotoxic and neurotoxic to humans and animals. However, the mechanisms of cyanobacterial neurotoxicity associated with MCs have not yet been clarified. This study reports the first observations of hepatic encephalopathy (HE) after exposure to Microcystis bloom extracts (MEs), which contained MCs. Mechanisms of toxicity were studied in rats exposed to MEs by use of a single intraperitoneal injection of 80 μg MC-LR equivalents/kg, body mass. Abnormal serum biochemical markers of hepatic functions and histopathological damage of liver and cerebral cortex were observed. Specifically, Alzheimer type II astrocytes, histological markers of HE, were observed. Motor impairment and significantly increased concentrations of ammonia in serum, increased activities of glutamine synthetase, and concentrations of glutamine in the cerebral cortex were detected, which indicated occurrence of HE. Mechanisms of HE, including ammonia poisoning, oxidative stress and inflammation, were confirmed by real-time quantitative PCR and transcriptomics. Also, transcriptomics revealed that zinc ions dyshomeostasis and ferroptosis are involved in the development of HE. This study presents novel insights into neurotoxic symptoms in human poisonings caused by Microcystis, links neurotoxicity in the brain to the liver, i.e., the liver-brain axis, and provides a new perspective on the multi-organ toxicity of Microcystis and a basis for developing treatments.

This study aimed to evaluate the cardiotoxic effects of metaflumizone (MTF), a commonly used pesticide, and the potential protective role of propolis (PROP) against MTF-induced cardiac damage. Twenty-eight male Wistar albino rats were randomly divided into four groups: Control, PROP (200 mg/kg), MTF (500 mg/kg), and MTF + PROP. All treatments were administered orally for 21 days. Biochemical, molecular (RT-qPCR), histopathological, and UHPLC-Orbitrap^®-HRMS analyses were performed to assess the outcomes. MTF administration significantly increased malondialdehyde (MDA) levels in whole blood and decreased glutathione (GSH) levels, indicating elevated oxidative stress. Additionally, superoxide dismutase (SOD) and catalase (CAT) activities were reduced in erythrocyte packs, further confirming systemic oxidative imbalance. At the molecular level, MTF suppressed the activities of PI3K, Akt, and mTOR in cardiac tissue and significantly upregulated the mRNA expression of TNF-α, IL-1β, IL-6, NF-κB, and Cyt-c. Histopathological evaluation revealed pronounced myocardial degeneration in the MTF group. In contrast, PROP supplementation effectively reversed these pathological alterations by restoring PI3K/Akt/mTOR pathway activity, attenuating oxidative and inflammatory responses, and preserving histological integrity. Collectively, the findings suggest that propolis exerts significant cardioprotective effects against MTF induced toxicity by modulating oxidative stress, inflammation, and apoptosis. These results provide the first in vivo evidence that propolis may mitigate MTF induced cardiotoxicity through regulation of oxidative stress, inflammation, and apoptosis.

Perfluorooctane sulfonate (PFOS) poses significant health and environmental risks due to its persistence and widespread use and has been linked to various adverse outcomes, such as liver toxicity. Although the molecular responses and toxicity effects of PFOS exposure have been extensively studied, considerable uncertainty remains regarding the causal mechanisms leading to PFOS-associated adverse effects. To help bridge this gap, we conducted CRISPR screens in HepG2/C3A human liver cells exposed to IC₂₅ (170 µM) of PFOS to identify genes and pathways influencing PFOS-induced cytotoxicity. Using a genome-wide CRISPR knockout library targeting 18,819 genes, we identified 340 candidate genes that modulate PFOS-induced cytotoxicity when genetically disrupted (189 gene disruptions increased sensitivity and 151 gene disruptions increased resistance). From these candidate genes, we individually disrupted two candidate genes, SLC6A9 which encodes the glycine transporter GlyT1, and CPSF2, and confirmed increased resistance to PFOS exposure. Further, molecular docking analysis predicts that PFOS directly binds to GlyT1 and functional inhibition of GlyT1 also increases resistance to PFOS exposure. Gene-Disease outcome association analysis using the Comparative Toxicogenomics Database (CTD) indicated an enrichment of candidate genes associated with cancer-related and liver disease phenotypes. KEGG and STRING enrichment analyses found over representation of several biological pathways including DNA damage response and cell cycle. Lastly, cross-species conservation analysis using the top two validated gene targets found that their pathways were highly conserved in several environmentally relevant species. These findings provide new mechanistic and functional insights into PFOS-induced cytotoxicity, highlight potential molecular targets for toxicity mitigation, and establish a foundation for cross-species toxicogenomic modeling of PFOS health effects.

Aristolochic acids (AAs), derived from Aristolochia herbs, are well-known nephrotoxins, and emerging evidence suggests their potential role in the development of liver cancers. However, the specific organs most affected by AAs, particularly in relation to liver cancer, remain unclear. Considering the known sex differences in enzyme activities, we hypothesized that variations in AA metabolism may contribute to the kidney and liver toxicity associated with these compounds. Our analysis of DNA adducts in the kidneys and livers of mice treated with aristolochic acid I (AA-I) revealed that male mice exhibited over 2.5 times higher levels of DNA adducts in their kidney DNA compared to female mice. Conversely, female mice showed 1.5 times higher adduct levels in their liver DNA than their male counterparts. These findings indicate that AA exposure presents a sex-specific disease risk, with males being at greater risk for kidney disease and females for liver disease. Additionally, we observed similar concentration patterns of the metabolite aristolactam I (AL-I) and the activity of NQO1 enzymes in the respective organs. Further in vitro studies, involving the incubation of AA-I with liver and kidney homogenates, demonstrated significant differences in AL-I concentrations, mirroring the trends observed in the AA-DNA adduct and AL-I analyses of AA-I-exposed mice. Collectively, these results underscore the importance of sex differences in the enzymatic activity responsible for the metabolic activation of AAs, which is critical for understanding the differential nephrotoxic and hepatotoxic effects associated with these compounds.

Trichloroethylene (TCE) remains a versatile organic solvent used globally. In recent years, immunological occupational diseases such as hypersensitivity syndrome (HS) and systemic sclerosis (SSc) have attracted attention in terms of the number of patients and the life-threatening consequences. This review summarizes mechanisms underlying HS pathogenesis based on the available literature. TCE-HS is a disease attributable to anti-CYP2E1 autoantibodies and HLA-B13:01 as susceptibility gene and is characterized by systemic skin lesions, severe-to-moderate liver damage, fever above 38 °C, leukocytosis, lymphadenopathy, and human herpesvirus 6 (HHV6) reactivation with elevated inflammatory cytokines, which are all similar to the characteristics of drug-induced HS. TCE-HS occurs on average 1 month after the commencement of exposure to TCE, which is shorter than the corresponding period for SSc. Recent epidemiological and animal studies have clarified the mechanism of pathogenesis: the oxidative metabolites chloral hydrate, dichloroacetyl chloride, and trichloroethanol, which are produced by CYP2E1, amplify the methylation of CD4⁺ T cells and activate them, resulting in the upregulation of cytokines such as TNF-α. Subsequently, some unidentified but oxidized metabolite haptens are assumed to activate CD8⁺ T cells with HLA-B*13:01, resulting in the production of anti-CYP2E1 autoantibodies. Subsequently, HHV6 is reactivated, leading to the development of skin and hepatic injuries. Whether skin lesions develop through a pathophysiological mechanism originating from hepatic lesions or by the same mechanism as the development of hepatic lesions remains unclear. Although disease contours have been clarified, further studies are required to elucidate its pathogenesis.