TOXICOLOGY LETTERS

Toxicological mode-of-action and developmental toxicity of different carbon chain length PFAS
Sodani K, Ter Braak B, Hartvelt S, Boelens M, Jamalpoor A and Mukhi S
Per-and polyfluoro alkyl substances (PFAS), also known as "forever chemicals", are deemed as highly toxic with similar toxicological mode-of-action (MoA) and potency. However, varying carbon chain length and functional head-group of PFAS can affect their physicochemical properties, resulting in different toxicological properties. To assess PFAS toxicological MoA and to distinguish between high toxic PFAS and the low-toxic analogs, we tested a set of eight PFAS with varying carbon chain length (C2-C10) in the ToxProfiler assay. ToxProfiler is a human in vitro assay containing seven fluorescent reporters to visualize and quantify activation of the major cellular stress pathways: oxidative stress, cell cycle stress, endoplasmic reticulum (ER) stress, autophagy, ion stress, protein stress and inflammation. In addition, we evaluated teratogenicity potential of long-chain PFAS perfluorooctanoic acid (PFOA; C8), and the ultrashort-chain PFAS trifluoroacetic acid (TFA; C2) in ReproTracker, a human induced pluripotent stem cell (hiPSCs)-based assay in which differentiation into cardiomyocytes, hepatocytes, and neural rosettes is followed to identify developmental toxicity hazards of new drugs and chemicals. In this study, we identified long-chain PFAS (C8-C10), such as PFOA (C8) to be more cytotoxic than ultrashort-chain PFAS and to predominantly induce ER and oxidative stress at 130 µM. PFAS with a carbon chain length of C4-C7 primarily induced autophagy (300 µM) in ToxProfiler. Ultrashort-chain PFAS trifluoroacetic acid (TFA; C2) and perfluoropropionic acid (PFPrA; C3) did not activate any of the ToxProfiler stress response reporters and were not cytotoxic at their maximum tested concentrations (10 mM). In concordance, exposure of differentiating cells to PFOA in ReproTracker led to a concentration-dependent decrease in the hepatocyte-specific and neuroectodermal biomarker genes and disrupted their morphology at 30 and 60 µM, respectively. TFA had no significant effect on biomarker expression, nor on the morphology/functionality of the three differentiated cells. Altogether, we demonstrated that the carbon chain length of PFAS can determine their in vitro toxicity and ultrashort-chain PFAS (TFA) were found to be less toxic when compared to long-chain PFAS.
Low doses of bisphenol F and S affect human ovarian granulosa cells by reducing the number of active mitochondria and ATP synthesis
Głód P, Marynowicz W, Homa J, Smoleniec J, Maduzia D and Ptak A
Bisphenols (BPs) are a group of environmental pollutants mainly represented by bisphenol S (BPS) and F (BPF). In ovaries, BPs can accumulate in follicular fluid (FF), changing the follicular microenvironment and simultaneously affecting ovarian granulosa cells (GCs) function. In the present study, we determined the effects of BPS and BPF on oxidative stress and mitochondrial function in human ovarian GCs. Single, short-term treatment with BPs at doses reflecting their concentrations in FF (10 nM) did not affect reactive oxygen species (ROS) levels but induced mitochondrial membrane depolarization. BPF-induced mitophagy decreased the number of active mitochondria and consequently reduced the ATP production rate. The observed changes did not translate into lowered viability of GCs, but long-term treatment with BPF influenced the intrinsic apoptosis pathway by increasing caspase 9 activity without affecting apoptosis. GCs are crucial for ovarian function as they produce primary steroid hormones and regulate oocyte maturation and follicle growth. Mitochondrial dysfunction caused by BPs, manifesting as reduced ATP production in GCs, can directly cause ovarian disorders such as infertility. Therefore, this study highlights the significance of investigating the effects of BPs on reproductive health.
Evaluation of the causal effects of perfluorooctanesulfonate on COVID-19 and its associated mechanisms: Integrated Mendelian randomization and network toxicology analyses
Tao W and Chen L
Observational reports have suggested that exposure to perfluorooctanesulfonate (PFOS) can influence COVID-19 infection-related parameters. This study thus sought to use integrated Mendelian randomization (MR) and network toxicology approaches to clarify the potential causal link between PFOS exposure and COVID-19 severity and the molecular mechanisms underlying this relationship. Inverse-variance-weighted analyses highlighted a causal link between plasma PFOS concentrations and a greater risk of sCOVID-19 (OR 1.293, 95 % CI 1.077-1.552, p = 0.006), but not of SARS-CoV-2 infection (p = 0.257) or COVID-19 hospitalization (p = 0.516). No causal link between PFOS concentration and sCOVID-19 was found by reverse MR. In total, 65 targets were tentatively linked to the relationship between PFOS exposure and sCOVID-19. GO and KEGG analyses highlighted involvement in pathways associated with kinase activity, inflammatory responses, and epithelial and endothelial cell migration. In molecular docking analyses, PFOS was confirmed to readily bind to all five analyzed core targets (IL10, ALB, NOTCH1, PPARG, and NFE2L2). These results suggest that PFOS exposure is causally linked to sCOVID-19 risk, while also offering promising insights into the mechanisms that may underlie this association and candidate targets for treatments aimed at limiting the negative effects of PFOS on COVID-19 severity.
Emerging nicotine analog 6-methyl nicotine increases reactive oxygen species in aerosols and cytotoxicity in human bronchial epithelial cells
Effah F, Sun Y, Friedman A and Rahman I
Nicotine-contained e-cigarettes (E-cigs) generate reactive oxygen species (ROS), volatile organic compounds, and heavy metals. Inhalation toxicology studies suggest that exposure to these toxicants may adversely impact human health. These findings led to the U.S. Food and Drug Administration's (FDA) regulation of nicotine-containing E-cigs under the Tobacco Regulation Act (TRA) of 2020. Manufacturers aiming to sell nicotine products in the U.S. must submit a Premarket Tobacco Product Application (PMTA) and obtain FDA approval before marketing their products. However, due to the lengthy PMTA process, some companies have exploited a loophole in the TRA (2020) by introducing nicotine analogs, such as 6-methyl nicotine (6-MN) into E-cig products. 6-MN is marketed as a 'safer' alternative to nicotine, offering comparable satisfaction despite not being derived from tobacco or nicotine. Nonetheless, its safety profiles are unknown. Therefore, this study tested the toxicity of 6-MN compared to traditional nicotine in vitro. We observed that thermal degradation of 6-MN in e-liquids significantly generated more ROS in the aerosols than nicotine. We investigated the dose-response cytotoxicity of 6-MN vs nicotine when exposed to HBEC3-KT human bronchial epithelial cells. 6-MN-contained e-liquids significantly increased cytotoxicity and intracellular ROS induction in a dose-specific manner compared to nicotine. Further, we observed that 6-MN (pure compound) transiently increased metabolic activity significantly at all doses tested compared to nicotine. Given the potential risks associated with 6-MN, it cannot be deemed 'safer' than nicotine. Therefore, further primary toxicological research is urgently needed to provide regulatory agencies with more robust data to implement regulations.
Mitigation of gentamycin induced acute kidney injury due to benzothiazole derivatives N1 and N5: Antioxidant and renoprotective mechanisms in-vivo zebrafish
Madesh S, Palaniappan S, Aravind A, Sau A, Almutairi MH, Almutairi BO, Soundharrajan I, Namasivayam SKR, Kumaradoss KM and Arockiaraj J
Acute kidney injury (AKI) is marked by a rapid decline in renal function, often caused by oxidative stress and nephrotoxic agents. Complications limit current therapeutic strategies, and no specific drugs are available to prevent renal injury or accelerate recovery. In the present research, we investigated the therapeutic efficacy of synthesized 2-aminobenzothiazole derivatives, N1 and N5, in mitigating Gentamicin (Gen) -induced renal damage in vivo zebrafish. The preliminary work of radical scavenging and hemolysis inhibition assay revealed that, both compounds exhibited strong antioxidant and anti-inflammatory activities. Furthermore, acute toxicity assays in zebrafish embryo/larvae revealed no adverse effects at concentrations up to 200 μM were tested, highlighting the safety of these compounds. In the zebrafish AKI model, Gen exposure led to oxidative stress, inflammation, and impaired glomerular filtration with tissue damage. Treatment with N1 and N5 significantly reduced ROS levels, apoptosis, and lipid peroxidation and restored antioxidant enzyme activities. Furthermore, N5 treatment improved renal filtration and reduced proteinuria levels, indicating its ability to mitigate nephrotoxic effects. Gene expression analysis showed that N1 and N5 downregulated pro-inflammatory markers (cox-2, tnfα, mpo) and angiogenic mediators (vegf, vegfr2), demonstrating anti-inflammatory and anti-angiogenic properties. Histological analyses revealed that N1 and N5 attenuated glomerular and tubular damage, reduced necrosis, and promoted tissue repair. These findings highlight the potential of 2-aminothiazole derivatives as effective therapeutic agents for AKI, offering antioxidant, anti-inflammatory, and cytoprotective benefits and warranting further investigation into their long-term efficacy in chronic kidney disease models.
The herbicide 2,4-dichlorophenoxyacetic acid induces pancreatic β-cell death via oxidative stress-activated AMPKα signal downstream-regulated apoptotic pathway
Lin KA, Su CC, Lee KI, Liu SH, Fang KM, Tang CH, Lia WC, Kuo CY, Chang KC, Huang CF, Chen YW and Yang CY
2,4-Dichlorophenoxyacetic acid (2,4-D) is one of commonly and widely used organic herbicides in agriculture. It has been reported that 2,4-D can induce adverse effects in mammalian cells. Epidemiological and animal studies have indicated that exposure to 2,4-D is associated with poorer glycemic control and impaired pancreatic β-cell function. However, limited information is available on 2,4-D-induced toxicological effects in β-cells, with the underlying toxicological mechanisms remains unclear. Herein, our results showed that 2,4-D exposure (30-500 μg/mL) significantly reduced cell viability, induced mitochondria dysfunction (including the mitochondrial membrane potential (MMP) loss, the increase in cytosolic cytochrome c release, and the change in Bcl-2 and Bax protein expression), and triggered apoptotic events (including the increased population of apoptotic cells, caspase-3 activity, and caspase-3/-7 and PAPR activation) in RIN-m5F β-cells, accompanied with insulin secretion inhibition. Exposure of cells to 2,4-D could also evoke JNK, ERK1/2, p38, and AMP-activated protein kinase (AMPK)α activation as well as reactive oxygen species (ROS) generation. Pretreatment of cells with compound C (an AMPK inhibitor) and the antioxidantN-acetylcysteine (NAC), but not that SP600125/PD98059/SB203580 (the inhibitors of JNK/ERK/p38, respectively), obviously attenuated the 2,4-D-triggered AMPKα phosphorylation, MMP loss, apoptotic events, and insulin secretion dysfunction,as similar effects with the transfection with AMPKα1-specific siRNA. Of note, buffering the ROS production with NAC obviously prevented the 2,4-D-induced ROS generation as well as AMPKα activation, but the either compound C and AMPKα1-specific siRNA transfection could not effectively reduce 2,4-D-induced ROS generation. Collectively, these findings indicate that the induction of oxidative stress-activated AMPKα signaling is a crucial mechanism underlying 2,4-D-triggered mitochondria-dependent apoptosis, ultimately leading to β-cell death.
The effects of citalopram and sertraline on adipogenesis and lipogenesis in 3T3-L1 cells
Bozdag D, Entezari B and Gurer-Orhan H
Selective serotonin reuptake inhibitors (SSRIs), widely used antidepressants, have been associated with metabolic adverse effects, including weight gain and disrupted lipid metabolism. This study investigates the potential adipogenic and lipogenic effects of two commonly prescribed SSRIs, citalopram (CIT) and sertraline (SER), using the murine 3T3-L1 preadipocyte cell line. Key markers, such as adiponectin secretion, G3PDH activity, and the expression of critical transcription factors (PPARγ, CEBPα, SREBP1) and lipogenic enzymes (FASN, LPL), were evaluated. Furthermore, assessment of intracellular lipid accumulation via Oil Red O staining was used as a measure for enhanced adipogenesis. The results show that CIT significantly increased adiponectin secretion and G3PDH activity, with comparable potency to the positive control, rosiglitazone. Both SSRIs upregulated the transcription of key adipogenic genes but displayed discrepancies in protein expression. Despite these molecular changes, neither CIT nor SER promoted lipid accumulation, indicating disruption of adipogenic and lipogenic processes without direct stimulation of fat storage. These findings underscore the complexity of SSRI-induced metabolic effects and the need for further studies to evaluate their long-term impact.
Neurotoxic implications of gliotoxin and ochratoxin A in SH-SY5Y cells: ROS-induced apoptosis and genotoxicity
Penalva-Olcina R, Juan C, Fernández-Franzón M and Juan-García A
Gliotoxin (GTX) and ochratoxin A (OTA) are naturally produced toxins by fungi and are known for their potential health risks. With the aim of shed some light on the mechanisms by which GTX, OTA, and their combination exert toxicity at neuronal level, the following in vitro studies were conducted in SH-SY5Y cells: a) intracellular ROS monitorization by the H2-DCFDA assay b) study of the expression of pro-apoptotic genes Bcl2, Casp-3, and Bax by RT-qPCR c) study of the apoptotic-necrotic progression of SH-SY5Y cells by flow cytometry; d) study of the genotoxic potential through the in vitro micronucleus (MN) assay also by flow cytometry following OECD TG 487 guidelines. ROS production was increased when cells were exposed to mycotoxins at all scenarios tested highlighting the effects of GTX. Regarding gene expression, increases of Bax and Casp-3 genes at 1.3- and 3- folds respectively were observed when cells were exposed to GTX at 0.75 μM, with a more prominent increase after exposure to the binary combination [GTX + OTA] at [0.2 + 0.1] µM, increasing 3 and 5-folds more, respectively when compared to the control. MN formation increased a 30 % compared to control when exposed to GTX at 0.4 μM, 43 % for OTA at 0.8 μM, with the highest increase observed when cells were exposed to the combination [GTX + OTA] at [0.2 + 1.5] μM, obtaining a 65 % more MN formation. Based on the results obtained, we can conclude that for the proposed scenarios of exposure to GTX, OTA, and their combination, genotoxic effects together with oxidative effects at neuronal level in SH-SY5Y cell line, were found to play a key role in their mechanisms of toxic action.
Corrigendum to "Review of the genotoxicity of "Arvin compounds", drinking water contaminants formed by the degradation of antioxidants in polyolefin pipes" [Toxicol. Lett. 402 (2024) 81-90]
Dekant W
The effects of occupational aluminum exposure on blood pressure and blood glucose in workers - A longitudinal study in northern China
Xue L, Guo S, Huan J, Li C, Song J, Wang L, Zhang H, Pan B, Niu Q, Lu X and Yin J
Trace element and metal exposure is closely related to the occurrence of chronic diseases, particularly affecting blood pressure and blood glucose. Current studies suggest that heavy metal exposure is a risk factor for hypertension and diabetes. Aluminum can enter the human body through daily life and occupational exposure from food, environment, drugs, and other sources, affecting the cardiovascular, endocrine, and other systems. Therefore, it is significant to observe the effect of aluminum on blood pressure and blood glucose in workers with high concentration.
Discovery of non-steroidal aldo-keto reductase 1D1 inhibitors through automated screening and in vitro evaluation
Kȩdzierski J, van Diest RE, Allard JA, Odermatt A and Smieško M
Steroid hormones regulate a wide range of physiological processes in the human body. However, exposure to xenobiotics can disrupt the hormonal balance by inhibition of enzymes involved in hormone synthesis or metabolism. Aldo-keto reductase 1D1 (AKR1D1) plays a key role in bile acid and steroid hormone metabolism by catalyzing the reduction of the double bond between C4 and C5 atoms of Δ(4)-steroids. In our previous work, we developed a model to screen for steroid-like xenobiotics that inhibit AKR1D1. In the current study, we used this model to screen for novel non-steroidal inhibitors. By applying an automatized screening approach, based on molecular docking and scoring in combination with post-docking refinement, 45 compounds were detected as potential hits and selected for in vitro evaluation. Among them, zardaverine was identified as the most potent inhibitor, with an IC value of 2.32 ± 1.27 μM. Other moderate inhibitors included carbamazepine, larotrectinib, endosulfan II, megastigmatrienone A, and mizolastine. The structural diversity of the identified inhibitors demonstrates that the binding site of AKR1D1 is rather promiscuous and can accommodate a broad range of ligands. These findings underscore the importance of toxicity screening and potential to identify structurally different AKR1D1 inhibitors.
A simple acetylcholinesterase inhibition assay for the quantification of the nerve agent VX: Application in a Franz cell model with rat skin and various decontaminants
Schwab A, Horn G, Kehe K, Worek F and Amend N
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 (k) and the inhibitor concentration [IX] were used to plot 1/k against 1/[IX]-(1-α). α equals [S]/(K+[S]), [S] being the substrate and K 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.
Mitophagy impairment drives microglia activation and results in cognitive deficits in neonatal mice following sevoflurane exposure
Zhang P, Cheng RJ, Yang QL, Gong Y, Xu Y, Chen LM, Zhou L and Jiang CL
Sevoflurane exposure induces cognitive deficits in neonatal mice. Mitophagy was closely correlated to sevoflurane inhalation induced neurotoxicity in developing brains. However, the underlying mechanisms have not been fully elucidated. In this study, we attempted to clarify the role of mitophagy in neonatal mice undergoing sevoflurane exposure. BV2 microglial cells were cultured, and mcherry-EGFP-LC3B adenovirus were transfected. The results showed that the fluorescence intensity of GFP was markedly increased after sevoflurane exposure, and rapamycin administration could mitigate this effect. The mitophagy flux test showed that sevoflurane exposure reduced the degree of colocalization between Mito-Traker and Lyso-Traker fluorescent, while which was elevated by rapamycin treatment. The immunofluorescence assay suggested that sevoflurane inhalation resulted in the significant decrease of autolysosome formation, which was sharply enhanced in SEV group after rapamycin treatment. Meanwhile, sevoflurane inhalation shifted microglial M1/M2 phenotypic polarization, and rapamycin administration reversed this status. Moreover, the degree of colocalization among Iba-1, Synaptophysin (Syn) and lysosomal-associated membrane protein 1 (Lamp1) was increased after sevoflurane exposure, and that was reduced following rapamycin treatment. The behavioral performance was worse after sevoflurane inhalation in neonatal mice, and rapamycin treatment effectively improved the cognitive outcome. Collectively, these findings demonstrated that mitophagy impairment induced by sevoflurane exposure promoted microglia M1 phenotypic polarization and enlarged phagocytosis, and resulted in cognitive deficits, while rapamycin administration effectively reversed this tendency.
Aristolochic acid-induced DNA adduct formation triggers acute DNA damage response in rat kidney proximal tubular cells
Komatsu M, Funakoshi T, Aki T and Unuma K
Aristolochic acid nephropathy (AAN) is a form of acute kidney injury triggered by the ingestion of aristolochic acid (AA), characterized by significant degeneration and loss of cells in the proximal tubules. Previous reports of AA-induced acute kidney injury have reported that AA-induced cytotoxicity can occur within a short period, up to 24 h; however, there are few reports on the relationship between AA-DNA adduct formation and cytotoxic mechanism during the acute phase. In this study, we aimed to elucidate the toxicological mechanisms in the initial phase of AA exposure by examining the effects of AA on NRK-52E rat proximal tubular cells within 24 h. We detected the formation of AA-DNA adducts as early as 4 h post-exposure, indicating that 50 μM of AA causes DNA damage. The DNA damage response pathway was activated, peaking at 8 h post-exposure. Additionally, we observed an increasing trend of G1 phase cell cycle arrest after 8 h, followed by a significant decline in cell viability at 16 h. These findings suggest that 50 μM of AA induces rapid DNA damage in NRK-52E cells, primarily through the formation of AA-DNA adducts, ultimately leading to G1 phase cell cycle arrest.
Iodoacetamide triggers ovarian dysfunction in mice through TGF-β signaling pathway and apoptosis
Xiao C, Li Q, Li M, Han Y, Xu H, Jiang H, Zhang S, Jin Z and Gao L
Iodoacetamide (IAcAm) is a harmful disinfection by-product. Studies have demonstrated that IAcAm can produce toxic effects in various tissues; however, its effect on female reproductive function remains unclear. To explore the effects of IAcAm on ovaries, we constructed a female mouse IAcAm toxicity model of free drinking model. The findings indicated that IAcAm exposure for five weeks did not affect the body growth of mice but increased the ovary/body weight ratio. At the tissue level, the numbers of atretic follicles increased. After the exposure, ovarian and blood samples were collected for analysis. IAcAm exposure caused changes in serum sex hormone levels, with an increase in follicle-stimulating hormone concentration(follicle-stimulating hormone) and a decrease in anti-Müllerian hormone concentration (anti-Müllerian hormone). Subsequent investigations revealed that IAcAm activated the transforming growth factor-β (TGF-β) signaling pathway and promoted ovarian fibrosis in mice. Simultaneously, IAcAm stimulated the granulosa cell apoptosis pathway and promoted granulosa cell apoptosis. Moreover, IAcAm interfered with mitochondrial function and increased reactive oxygen species, leading to a decrease in oocyte developmental potential. In conclusion, IAcAm exposure causes ovarian inflammation and leads to mitochondrial dysfunction in oocytes, affecting follicle maturation and reducing oocyte quality.
Binding of ligands to the aryl hydrocarbon receptor: An overview of methods
Hrubý J and Dvořák Z
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.
Modernizing toxicology: The importance of accessible NAM training
Slankster-Schmierer E
Current toxicology curricula and certifications are heavily reliant on animal-based research and lack mandatory education and training in New Approach Methodologies (NAMs). Traditional animal-based toxicological methods come with many concerns, including translatability and reproducibility, which NAMs are aptly positioned to address. The NAM Use for Regulatory Application (NURA) program aims to bridge this educational gap by providing training to toxicologists, method developers, regulators, and legislators on the use of NAMs, helping to build confidence in NAM use and facilitate the shift to more human-based methods.
Involvement of mitochondrial dysfunction and oxidative stress in the nephrotoxicity induced by high-fat diet in Sprague-Dawley rats
Zhang B, Xu J, Wang M and Yu C
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 uncoupling protein-2 (UCP-2) and proliferator-activated receptor gamma coactivator 1-alpha (PGC1α)-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.
Zanamivir alleviates ethanol intoxication through activating catalase
Guan Z, Tian D, Wang M, Meng X, Kang J, Hu Z, Xu H, Ma X, Jin T, Gao X, Zhang Y, Gu Y, Liu X and Chen X
Acute alcohol intoxication is characterized as high morbidity and mortality. To explore new chemicals to relieve ethanol intoxication, we tried to explore the activators of catalase (CAT), an enzyme responsible for oxidization of ethanol into acetaldehyde to accelerate ethanol removal.
Characterization of cell membrane fragments containing muscle type nAChR from Tetronarce californica after preparation using high pressure homogenization
Springer F, Freisleben M, Muschik S, Worek F, Seeger T, Meinel L and Niessen KV
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 and B values were determined using a scintillation proximity assay (SPA) with [H]epibatidine as reporter ligand. Measurement data showed that the ideal conditions to obtain microsomal membrane fragments with high pressure homogenization were four runs at 400 bar. 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.
Lithium attenuates ketamine-induced long-term neurotoxicity through DISC1-mediated GSK-3β/β-catenin and ERK/CREB pathways
Yang TT, Guo ZW, Zhang F, Peng Y, Yu W, Gao GQ, Tian H, Zhang SJ and Liu JR
Ketamine, an antagonist of N-methyl-D-aspartate receptor, is extensively employed in pediatric anesthesia. Multiple studies have shown that repeated ketamine exposure induces neuroapoptosis, synaptic changes and cognitive deficits during neurodevelopment. Therefore, it is essential to elucidate the mechanisms of ketamine-induced neurotoxicity and develop therapies to mitigate its harmful effects. Here, we investigated the role of disrupted in Schizophrenia 1 (DISC1) in ketamine-induced long-term neurotoxicity through a ketamine-exposed neuroapoptosis model. Neonatal rats received 2-5 intraperitoneal injections of ketamine (20 mg/kg b.w.) at 90 min intervals. Another cohort of pups received five intraperitoneal injections of ketamine (20 mg/kg×5 b.w.) with or without lithium (120 mg/kg×5 b.w.) at 90 min intervals over 6 h. Neuroapoptosis, DISC1-associated proteins expression in rats treated with ketamine, lithium, or a combination of both were detected, and the cognitive function of adolescent rats was evaluated by Morris water maze test. The length of dendrites and axons of primary neurons treated with lithium and ketamine were further measured. Results showed that ketamine time-dependently downregulated the levels of DISC1, pGSK-3β, β-catenin, pERK, pCREB and PSD95 in neonatal rats. Lithium could ameliorate neuroapoptosis, cognitive deficits and neurite growth inhibition triggered by ketamine. Mechanistically, lithium upregulated the levels of DISC1, PSD95 and GSK-3β/β-catenin and ERK/CREB signaling-related proteins. Consequently, lithium mitigated ketamine-induced long-term neurotoxicity by elevating DISC1 level and activating the GSK-3β/β-catenin and ERK/CREB signaling pathways.