Toxicology letters最新文献

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor, which plays numerous and pivotal roles in human physiology and pathophysiology. Therefore, pharmacotherapeutic targeting of the AhR is a highly pertinent issue. The identification of new AhR ligands and the characterization of the interactions between the AhR ligands and AhR protein requires appropriate methodology. In spite the AhR is monomeric intracellular soluble receptor, the full-length human AhR protein has not been crystallized so far, and its isolation in a form applicable in the binding assays is highly challenging. Recent advances, including crystallization of AhR fragments, recombinant protein technologies, and cryogenic electron microscopy, allowed for exploitation of diverse experimental techniques for studying interactions between ligands and the AhR. In the current paper, we review existing AhR ligand binding assays, including their description, applicability and limitations.

The prevalence of obesity-associated kidney injury has increased, yet the precise extent of the injury and its underlying mechanisms remain unclear. This study used a Sprague-Dawley (SD) rat model to simulate human exposure scenarios, with the objective of investigating the involvement of mitochondria in obesity-induced renal toxicity. Biochemical analysis revealed significant increases in serum creatinine, cystatin C, urinary protein, urinary microalbumin, and urinary α1-microglobulin levels in rats fed a high-fat diet, indicating a notable decline in glomerular filtration function. Histopathological examination showed mild to moderate degeneration in renal tubular epithelial cells, slight glomerular enlargement, fusion and disappearance of pedunculated cell, and decreased electron density of mitochondrial matrix and cristae, indicating the impaired filtration function of kidney. Furthermore, the study found reduced mitochondrial membrane potential and superoxide dismutase (SOD) levels, along with increased malondialdehyde (MDA) levels, signifying elevated mitochondrial oxidative stress in the kidneys of high-fat diet-fed rats. Additionally, a decrease in the number of mitochondrial proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) and uncoupling protein-2 (UCP-2)-positive cells, as well as reduced protein expression levels in the mitochondria, suggests a reduced renal mitochondrial resistance to oxidative stress. Collectively, these findings indicate that a high-fat diet triggers abnormalities in both renal filtration and structural functionality in SD rats. The observed reduction in renal mitochondrial density and the elevation in oxidative stress levels could potentially serve as underlying mechanisms.

The medical community continues to regard organophosphate nerve agent poisoning as a significant concern. Due to the lack of therapeutic options for the nicotinic signs and symptoms for certain agents (e.g. tabun), decontamination remains a pivotal aspect of patient care. Current models to study skin penetration of nerve agents and the respective decontamination rely on expensive, laborious and not readily available methods, i.e. GC-MS-MS and LC-MS-MS. Hence, we used a photometric acetylcholinesterase (AChE) inhibition assay for the quantification of nerve agents, relying on VX as a model substance. Inhibition curves were determined in a time dependent manner and consecutively slopes of the tangents and the calculated standard curve were used for quantification. The concentration dependent rate constant of VX with human AChE (k₁) and the inhibitor concentration [IX] were used to plot 1/k₁ against 1/[IX]-(1-α). α equals [S]/(K_m+[S]), [S] being the substrate and K_m the Michaelis-Menten-constant. A Franz cell model served as an example to determine the robustness and suitability of the assay to study penetration rates and the success of decontamination. The inhibition assay delivers robust results, even when the decontamination protocol interferes with the colorimetric Ellman assay. Hence, we provide a generic, low-cost method for the quantification of nerve agents in a model studying the decontamination of nerve agents.

The nicotinic acetylcholine receptor (nAChR) is a pentameric ligand-gated ion channel (pLGIC) commonly used as a model for receptors belonging to the Cys-loop superfamily. Members of pLGICs are standardly used in numerous toxicological investigations e.g., GABA and nAChR in the context of nerve agent poisoning. Organophosphorus compounds inhibit AChE, leading to accumulation of acetylcholine in the synaptic cleft and subsequently to a cholinergic crisis, in part through desensitization of nAChR. Due to the limitations of standard therapy, studies concerning functional ligand-receptor interactions of therapeutically active substances are of high importance. Therefore, we developed a novel method to obtain muscle type nAChR-containing membrane fragments from native tissue using high-pressure homogenization. The obtained microsomal fragments were characterized using Dynamic Light Scattering, laser Doppler electrophoresis and protein concentration. The microsomal membrane fragments were further purified, and the plasma membrane fraction was enriched using different density gradients. K_D and B_Max values were determined using a scintillation proximity assay (SPA) with [³H]epibatidine as reporter ligand. Measurement data showed that the ideal conditions to obtain microsomal membrane fragments with high pressure homogenization were four runs at 400bar. For density gradient centrifugation the under layering of the microsomal membrane fragments (bottom-up method) is to be preferred for further purification. Sucrose seems to be more efficient compared to xylitol or iodixanol density gradients. The nAChR-containing plasma membrane fractions resulting from the developed purification protocol achieve a high degree of quality and reproducibility, making them suitable to model physiological conditions. This system has the potential to be used in both bead- and filtration-based assays probing affinity parameters for ligand binding or functional experiments. The protocol can be easily modified for other LGICs or transmembrane proteins, allowing for further expansion of its use.

Osthole (OST), a coumarin derivative, is one of the major components of Cnidium monnieri (L.) Cussion. OST was reported to induce apoptosis in hepatocytes. Elevated serum ALT and AST were documented in Sprague-Dawley rats after administration of OST. In the present study, OST was found to be metabolized to a phenol metabolite which was further metabolically oxidized to the corresponding quinone methide intermediate. A glutathione conjugate derived from the reactive metabolite was detected in vitro and in vivo. The structures of the metabolites were verified by chemical analysis. CYP3A4 and CYP1A2 were the major enzymes to catalyze the oxidation reactions. Pre-treatment with 1-aminobenzotriazole or ketoconazole decreased the susceptibility of primary hepatocytes to the cytotoxicity of OST. The findings provided solid evidence that the metabolic activation of OST correlated with the cytotoxicity of OST.

Rare earth is used extensively around the world, and rare earth particles cause a respiratory disease in workers termed rare earth pneumoconiosis(REP) that have attracted considerable attention. However, the mechanisms of REP, characterized by diffuse pulmonary fibrosis, are elusive. REP progression involves various signaling pathway networks comprising numerous cell types and cytokines. Acting as an important medium for communication between cells, exosomes are emerging as a major research topic. However, the role of exosomal lncRNAs, miRNAs and mRNAs in REP remains unclear. In the present study, we conducted high-throughput RNA sequencing to generate long non-coding RNA(lncRNA), microRNA (miRNA) and mRNA profiles from the serum exosomes of nine patients with rare earth pneumoconiosis and nine healthy people. Our results identified a total of 94 lncRNAs, 93miRNAs, and 29 mRNAs were differentially expressed in the serum exosomes of patients with rare earth pneumoconiosis. Subsequently, Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were used to analyze the differentially expressed RNAs. The abundant enriched GO terms of exosomal genes are cytoplasm, protein binding, cytoskeleton, Nuclear cytoplasmic transport, and KEGG pathways of exosomal genes included metabolic and cancer pathway, PI3K/Akt, wnt, mTOR, HIF-1, actin cytoskeleton and cell cycle and so on. RT-qPCR results showed that lnc-KCNMB2-AS1, hsa-miR-186-5p, hsa-miR-100-5p, hsa-miR-381-5p, NCOA4 and PLXDC1 were up-regulated, and lnc-TMEM151A, hsa-miR-758-5p and hsa-miR-6842-5p were significantly down-regulated in exosomes. In addition, our study fuond that the PI3K/Akt pathway was activated, and the expression level of miR-100-5p was increased synchronously in lung tissue of mice exposed to rare earth Nd₂O₃. In this study, PI3K/Akt pathway is significant helpful in elucidating the mechanism of REP. These findings can provide new insights into the mechanism of REP and develop a novel treatment strategy and biomarker.

Cannabis sativa is a complex plant, renowned for its diverse array of bioactive compounds, the most prominent of which are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). These compounds exhibit markedly opposing pharmacological effects, with THC being primarily psychoactive and CBD known for its non-psychoactive properties. In recent years, there has been growing interest in the potential health implications of these compounds, particularly concerning male reproductive health. Accumulating evidence over the past decade has alluded to the potential negative effects of THC, including its association with reduced sperm quality, altered hormone levels, changes in genetic and epigenetic profiles, and potential impacts on fertility. Conversely, emerging studies suggest that CBD may exert protective and beneficial effects on male reproductive health, possibly through its anti-inflammatory and antioxidant properties. This review aims to provide a comprehensive analysis of the current scientific literature, delineating the mechanisms by which THC and CBD influence male reproductive health, highlighting the disparities in their effects, and discussing the clinical and therapeutic implications of these findings.

Cisplatin is widely used in anti-tumor therapy, but the ototoxicity caused by high-dose cisplatin often limits its efficacy, and the specific mechanism of cisplatin-induced cochlear damage is still not perfect. The Wnt/β-catenin signaling pathway is closely related to aging, embryonic development, and apoptosis. Meanwhile, B lymphoma Moloney murine leukemia virus insertion region 1 (BMI1) plays a certain role in the evolution and development of the inner ear and the occurrence and development of inner ear-related diseases. Our study intends to explore the role and specific mechanism of the Wnt/β-catenin signaling pathway and BMI1 in improving cisplatin ototoxicity. The appropriate experimental concentrations for each drug were selected by CCK-8 cell proliferation assay and Western Blot to detect apoptosis. The lentivirus transfection of HEI-OC1 cochlear hair cells was used to overexpress BMI1. Western Blot, qPCR, and immunofluorescence detected the activation of each component of BMI1 and Wnt/β-catenin signaling pathway in each experimental model. Wnt/β-catenin signaling pathway and BMI1 are jointly involved in cisplatin-induced cell injury. Low lithium chloride (LiCl) concentrations activated the Wnt/β-catenin pathway, increased BMI1 expression, and reduced cisplatin-induced hair cell injury. In contrast, overexpression of BMI1 inhibited the Wnt/β-catenin pathway and reduced hair cell injury. Meanwhile, the increased cisplatin-induced damage to hair cells by inhibiting BMI1 could not be rescued by LiCl. In conclusion, LiCl can ameliorate cisplatin ototoxicity by elevating BMI1 expression through activation of the Wnt/β-catenin pathway. Overexpression of BMI1 inhibits the Wnt/β-catenin pathway and reduces cisplatin-induced hair cell damage.

Manganese is an essential trace element required for various physiological processes. However, excessive exposure to this metal can lead to health issues. This study aims to evaluate whether adequate zinc intake can influence the relationship between blood manganese levels and markers indicating damage to the liver and other organs in populations using epidemiological data. We conducted a comprehensive analysis utilizing 2013-2016 data from the National Health and Nutrition Examination Survey (NHANES). The findings indicated that blood manganese exhibits a significant positive association with the serum levels of enzymatic markers of liver damage alkaline phosphatase and aspartate aminotransferase. However, when investigating the interaction between blood manganese and zinc intake at the second quartile, a significant negative association was found with alkaline phosphatase in three different linear regression models. A similar association was found between the fourth quartile of zinc intake and lactate dehydrogenase activity in all three models of the study. The findings suggest that unhealthy high levels of manganese in populations may lead to tissue injury and disease. Nevertheless, having an adequate zinc intake could help mitigate manganese toxicity.