An 8-(Diazomethyl) Quinoline Derivatized Acyl-CoA in Silico Mass Spectral Library Reveals the Landscape of Acyl-CoA in Aging Mouse Organs.

Acyl-Coenzyme As (acyl-CoAs) are essential intermediates to incorporate carboxylic acids into the bioactive metabolic network across all species, which play important roles in lipid remodeling, fatty acids, and xenobiotic carboxylic metabolism. However, due to the poor liquid chromatographic behavior, the relatively low mass spectrometry (MS) sensitivity, and lack of authentic standards for annotation, the in-depth untargeted profiling of acyl-CoAs is challenging. We developed a chemical derivatization strategy of acyl-CoAs by employing 8-(diazomethyl) quinoline (8-DMQ) as the labeling reagent, which increased the detection sensitivity by 625-fold with good peak shapes. By applying the MS/MS fragmentation rules learned from the MS/MS spectra of 8-DMQ-acyl-CoA authentic standards, an 8-DMQ-acyl-CoA in silico mass spectral library containing 33,344 high-resolution tandem mass spectra of 8,336 acyl-CoA species was created. The in silico library facilitated the high-throughput and automatic annotation of acyl-CoA using multiple metabolomic data processing tools, such as NIST MS Search and MSDIAL. The feasibility of the in silico library in a complex sample was demonstrated by profiling endogenous acyl-CoAs in multiple organs of an aging mouse. 53 acyl-CoA species were annotated, including 12 oxidized fatty acyl-CoAs and 3 novel nonfatty acyl-CoAs. False positive annotations were further screened by developing an eXtreme Gradient Boosting (XGBoost) based retention time prediction model. The organ distribution and the aging dynamics of acyl-CoAs in a mouse model were discussed for the first time, which helped to elucidate the organ-specific function of acyl-CoAs and the role of different acyl-CoA species during aging.

Applications of 3D organoids in toxicological studies: a comprehensive analysis based on bibliometrics and advances in toxicological mechanisms.

A mechanism exploration is an important part of toxicological studies. However, traditional cell and animal models can no longer meet the current needs for in-depth studies of toxicological mechanisms. The three-dimensional (3D) organoid derived from human embryonic stem cells (hESC) or induced pluripotent stem cells (hiPSC) is an ideal experimental model for the study of toxicological effects and mechanisms, which further recapitulates the human tissue microenvironment and provides a reliable method for studying complex cell-cell interactions. This article provides a comprehensive overview of the state of the 3D organoid technology in toxicological studies, including a bibliometric analysis of the existing literature and an exploration of the latest advances in toxicological mechanisms. The use of 3D organoids in toxicology research is growing rapidly, with applications in disease modeling, organ-on-chips, and drug toxicity screening being emphasized, but academic communications among countries/regions, institutions, and research scholars need to be further strengthened. Attempts to study the toxicological mechanisms of exogenous chemicals such as heavy metals, nanoparticles, drugs and organic pollutants are also increasing. It can be expected that 3D organoids can be better applied to the safety evaluation of exogenous chemicals by establishing a standardized methodology.

Mitophagy and its regulatory mechanisms in the biological effects of nanomaterials.

Mitophagy is a selective cellular process critical for the removal of damaged mitochondria. It is essential in regulating mitochondrial number, ensuring mitochondrial functionality, and maintaining cellular equilibrium, ultimately influencing cell destiny. Numerous pathologies, such as neurodegenerative diseases, cardiovascular disorders, cancers, and various other conditions, are associated with mitochondrial dysfunctions. Thus, a detailed exploration of the regulatory mechanisms of mitophagy is pivotal for enhancing our understanding and for the discovery of novel preventive and therapeutic options for these diseases. Nanomaterials have become integral in biomedicine and various other sectors, offering advanced solutions for medical uses including biological imaging, drug delivery, and disease diagnostics and therapy. Mitophagy is vital in managing the cellular effects elicited by nanomaterials. This review provides a comprehensive analysis of the molecular mechanisms underpinning mitophagy, underscoring its significant influence on the biological responses of cells to nanomaterials. Nanoparticles can initiate mitophagy via various pathways, among which the PINK1-Parkin pathway is critical for cellular defense against nanomaterial-induced damage by promoting mitophagy. The role of mitophagy in biological effects was induced by nanomaterials, which are associated with alterations in Ca2+ levels, the production of reactive oxygen species, endoplasmic reticulum stress, and lysosomal damage.

An MLWE-Based Cut-and-Choose Oblivious Transfer Protocol.

The existing lattice-based cut-and-choose oblivious transfer protocol is constructed based on the learning-with-errors (LWE) problem, which generally has the problem of inefficiency. An efficient cut-and-choose oblivious transfer protocol is proposed based on the difficult module-learning-with-errors (MLWE) problem. Compression and decompression techniques are introduced in the LWE-based dual-mode encryption system to improve it to an MLWE-based dual-mode encryption framework, which is applied to the protocol as an intermediate scheme. Subsequently, the security and efficiency of the protocol are analysed, and the security of the protocol can be reduced to the shortest independent vector problem (SIVP) on the lattice, which is resistant to quantum attacks. Since the whole protocol relies on the polynomial ring of elements to perform operations, the efficiency of polynomial modulo multiplication can be improved by using fast Fourier transform (FFT). Finally, this paper compares the protocol with an LWE-based protocol in terms of computational and communication complexities. The analysis results show that the protocol reduces the computation and communication overheads by at least a factor of n while maintaining the optimal number of communication rounds under malicious adversary attacks.

Recombinant human metallothionein-III alleviates oxidative damage induced by copper and cadmium in Caenorhabditis elegans.

Recombinant human metallothionein III (rh-MT-III) is a genetically engineered product produced by Escherichia coli fermentation technology. Its molecules contain abundant reducing sulfhydryl groups, which possess the ability to bind heavy metal ions. The present study was to evaluate the binding effects of rh-MT-III against copper and cadmium in vitro and to investigate the antioxidant activity of rh-MT-III using Caenorhabditis elegans in vivo. For in vitro experiments, the binding rates of copper and cadmium were 91.4% and 97.3% for rh-MT-III at a dosage of 200 µg/mL at 10 h, respectively. For in vivo assays, the oxidative stress induced by copper (CuSO4 , 10 µg/mL) and cadmium (CdCl2 , 10 µg/mL) was significantly reduced after 72 h of exposure to different doses of rh-MT-III (5-500 µg/mL), indicated by restoring locomotion behavior and growth, and reducing malondialdehyde and reactive oxygen species levels in C. elegans. Moreover, rh-MT-III decreased the deposition of lipofuscin and fat content, which could delay the progression of aging. In addition, rh-MT-III (500 µg/mL) promoted the up-regulation of Mtl-1 and Mtl-2 gene expression in C. elegans, which could enhance the resistance to oxidative stress by increasing the enzymatic activity of antioxidant defense system and scavenging free radicals. The results indicated that supplemental rh-MT-III could effectively protect C. elegans from heavy metal stress, providing an experimental basis for the future application and development of rh-MT-III.

Zinc offers splenic protection through suppressing PERK/IRE1-driven apoptosis pathway in common carp (Cyprinus carpio) under arsenic stress.

Arsenic (As) occurs naturally and concentrations in water bodies can reach high levels, leading to accumulation in vital organs like the spleen. Being an important organ in immune response and blood development processes, toxic effects of As on the spleen could compromise immunity and cause associated disorders in affected individuals. Splenic detoxification is key to improving the chances of survival but relatively little is known about the mechanisms involved. Essential trace elements like zinc have shown immune-modulatory effects humans and livestock. This study aimed to investigate the mechanisms involved in As-induced splenic toxicity in the common carp (Cyprinus carpio), and the protective effects of zinc (Zn). Our findings suggest that environmental exposure to As caused severe histological injuries and Ca2+ accumulation in the spleen of common carp. Additionally, transcriptional and translational profiles of endoplasmic reticulum stress, apoptosis and autophagy-related genes of the spleen showed upward trends under As toxicity. Treatment with Zn appears to offer protection against As-induced splenic injury in common carp and the pathologic changes above were alleviated. Our results provide additional insight into the mechanism of As toxicity in common carp while elucidating the role of Zn, a natural immune-modulator, as a potential antidote against As poisoning.

Zinc application alleviates the adverse renal effects of arsenic stress in a protein quality control way in common carp.

The potential antagonistic mechanism between zinc (Zn) and arsenic (As) on renal toxicity was investigated in common carp. The results showed that by increased Zn efflux and retention (as reflected by zinc transporter 1 (ZnT-1), Zrt- and Irt- 1ike protein (ZIP) and metallothionein (MT) expression), Zn co-administration significantly recovered the antioxidant function (catalase, CAT) and the level of renal barrier function (Occludin, Claudins and Zonula Occludens) in comparison to As treatment. Interestingly, Zn co-administration with As resulted in carps undergoing reduction of heat shock response (HSPs), a low induction of autophagy flux (Beclin-1, microtubule-associated protein 1 light chain 3 (LC3) and sequestosome 1 (P62)) and decreased endoplasmic reticulum (ER) stress (activating transcription factor 6 (ATF-6), inositol requiring-1α (IRE1) and PKR-like ER kinase (PERK)) in the aspect of mRNA or protein levels. All these alleviated protein quality control processes induced by Zn under As stress was correlated with the no longer loosen tight connection, less swollen endoplasmic reticulum as well as reduced formation of autophagosomes and autophagic vesicles. Mechanically, post-transcriptional regulated protein quantities compromising phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway was demonstrated true causative forces inside the cell for Zn against As poisoning. In conclusion, we suggested the potential renal protective effect of Zn supplementation against As exposure by the modulation of protein quality control processes.

As3+ or/and Cu2+ exposure triggers oxidative stress imbalance, induces inflammatory response and apoptosis in chicken brain.

Arsenic (As) and copper (Cu) are common environmental pollutants in nature. When they are excessively present in living organisms, they can cause heavy metal poisoning. There were relatively few studies of the toxicological concentrations of As and Cu in the brain using chicken as a model. Therefore, in this study, arsenic trioxide or/and copper sulfate were added to chicken diets for a 12-week toxicity test. The test results showed that excessive intake of As or/and Cu led to a significant reduction in the total antioxidant capacity (T-AOC), catalase (CAT) and hydroxyl radicals. And significant increase in nitric oxide synthase (NOS) indicates an imbalanced oxidation reaction. In addition, the increase in heat shock protein (HSPs), the increase of NF-κB pathway-related pro-inflammatory mediators, the change of apoptosis factors on the death receptor and mitochondrial apoptosis pathway show that, As or/and Cu exposure induced chicken brain has heat shock response (HSP), tissue inflammation and apoptosis. This damage is inseparable from the oxidative imbalance. It is worth noting that these injury changes are time-dependent, and the combined effect of these two metals is more severe than that of a single group of injuries. Our findings can inform the regulation of animal feed additives and avoid agricultural economic losses or biological health damage.

Arsenic (III) or/and copper (II) exposure induce immunotoxicity through trigger oxidative stress, inflammation and immune imbalance in the bursa of chicken.

The environmental hazards of arsenic (As) and copper (Cu) contamination have swept through quite a few districts worldwide. Whereas, molecular mechanisms involved in As- and Cu-induced immunotoxicity in Gallus gallus bursa of Fabricius (BF) are complex and elusive. Male Hy-line chickens were exposed to arsenic trioxide (As2O3; 30 mg/kg) and copper sulfate (CuSO4; 300 mg/kg) alone or in combination, respectively, to examine the potential ecotoxicity of them. The ions homeostasis and BF index of chicken had distinct changes after As or/and Cu exposure. Moreover, As or/and Cu treatment significantly increased the MDA content and NOS activity, and simultaneously resulted in reductions in CAT and AHR activities. Subsequently, it was further exhibited up-regulations of nuclear factor-κB (NF-κB), inflammatory mediators and pro-inflammation cytokines accompanied by depletion of anti-inflammatory cytokines and severe pathological conditions. Moreover, decreased ratio of IFN-γ/IL-4 and increased level of IL-17 illustrated an imbalance of the immune response. Meanwhile, incremental mRNA transcription and protein levels of heat shock proteins (HSPs) alleviated toxicity caused by As or/and Cu. Importantly, exposure to both contaminants significantly soared the BF injury in comparison with exposure to As or Cu alone. All these results illustrated that exposure to As2O3 or/and CuSO4 elicited BF tissue damage and ions changes, and its severity was associated with prolonged persistence of oxidative damage, accompanied by a dysregulated immune response which played a vital role in inflammatory injury. Additionally, combined management of As2O3 and CuSO4 could exacerbate BF injury.

Zinc alleviates arsenism in common carp: Varied change profiles of cytokines and tight junction proteins among two intestinal segments.

This study was designed to evaluate the effects of zinc on inflammation and tight junction (TJ) in different intestinal regions of common carp under sub-chronic arsenic insult. Fish were exposed to zinc (0, 1 mg/L) and arsenic trioxide (0, 2.83 mg/L) in individual or combination for a month. Inflammatory infiltration and TJ structure changes were displayed by H&E staining and transmission electron microscope. To further explore these changes, biochemical indicator (SOD), gene or protein expressions of inflammatory responses (NF-κB, IL-1ß, IL-6 and IL-8) and TJ proteins (Occludin, Claudins and ZOs) were determined. In the anterior intestine, arsenic decreased activity of SOD, mRNA levels of Occludin, Claudins and ZOs, increased mRNA levels of ILs. However, unlike the anterior intestine, arsenic has an upregulation effects of Occludin and Claudin-4 in the mid intestine. These anomalies induced by arsenic, except IL-8, were completely or partially recovered by zinc co-administration. Furthermore, transcription factor (NF-κB) nuclear translocation paralleled with its downstream genes in both intestinal regions. In conclusion, our results unambiguously suggested that under arsenic stress, zinc can partly relieve intestinal inflammation and disruption of tight junction segment-dependently.

Destruction of redox and mitochondrial dynamics co-contributes to programmed cell death in chicken kidney under arsenite or/and copper (II) exposure.

BACKGROUND: Sub-chronic arsenic (arsenite) exposure-induced oxidative toxicity leads to adverse effects in various organ systems, especially the kidney. Copper sulphate (Cu2+), known for its extensive uses in agriculture, has also been reported to have pro-oxidation properties. Both of these two potential toxic elements can bio-accumulate through food chain, thus endangering human health. However, their interaction study in the kidney is scanty. AIM: To investigate the synergism effects of Cu2+ in arseniasis-elicited oxidative stress and cascaded renal injury in chickens. RESULTS: Arsenite intoxication decreased renal antioxidant system along with ATPases. Arsenite exposure also significantly elicited disequilibrium of mitochondrial homeostasis, accompanying by elevated apoptotic and autophagic cell death. The disturbed morphological and ultrastructural changes further corroborated arsenite nephrotoxicity. These anomalies aligned with the findings in Cu2+ groups, which co-administrated with arsenic further deteriorated these pathological changes. This synergism was achieved partially via the inactivation of phosphoinositide-3-kinase/protein kinase b/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway through the activation of P53. CONCLUSIONS: Copper excess and arsenic exposure can function independently or cooperatively to affect oxidative stress, mitochondrial dynamics and programmed cell death. These results highlighted the need to take precautions against copper and arsenic co-exposure when considering their impact in susceptible animals/populations.

Molecular mechanisms of silver nanoparticle-induced neurotoxic injury and new perspectives for its neurotoxicity studies: A critical review.

Silver nanoparticles (AgNPs) garnered significant attention and applications in the field of nanotechnology due to their unique physicochemical properties. However, with the increasing exposure of AgNPs in the environment and biological systems, concerns about their potential neurotoxicity have also risen. Recent studies on the neurotoxic effects and mechanisms of AgNPs have often relied on traditional toxicological research methods and perspectives. This reliance has limited the extrapolation of these findings to the human brain environment and hindered a deep understanding of the neurotoxicity of AgNPs. This review first outlines the molecular mechanisms of AgNPs-induced neurotoxic injury from a traditional research perspective, identifying oxidative stress, inflammatory responses, and autophagy disorders as key areas of current research. Related molecular signaling pathways, including the nuclear transcription factor-κB (NF-κB) signaling pathway, the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, and the calcium signaling pathway, have been implicated in the neurotoxic injury process induced by AgNPs. Subsequently, we elucidated the unique advantages of the 3D brain organoids applied to the neurotoxicity study of AgNPs by drawing on relevant studies in the same field. We also emphasize that establishing a standardized 3D brain organoids construction platform is a crucial prerequisite for its widespread application. Furthermore, we suggest that future studies should explore the neurotoxicity mechanisms of AgNPs through the lenses of "adaptive homeostasis" and "structure-activity relationship analysis". In conclusion, the neurotoxicity of AgNPs should be comprehensively evaluated by integrating new research techniques and perspectives, ultimately allowing these nanoparticles to better serve human society.

Tuning Vision-Language Models with Multiple Prototypes Clustering.

Benefiting from advances in large-scale pre-training, foundation models, have demonstrated remarkable capability in the fields of natural language processing, computer vision, among others. However, to achieve expert-level performance in specific applications, such models often need to be fine-tuned with domain-specific knowledge. In this paper, we focus on enabling vision-language models to unleash more potential for visual understanding tasks under few-shot tuning. Specifically, we propose a novel adapter, dubbed as lusterAdapter, which is based on trainable multiple prototypes clustering algorithm, for tuning the CLIP model. It can not only alleviate the concern of catastrophic forgetting of foundation models by introducing anchors to inherit common knowledge, but also improve the utilization efficiency of few annotated samples via bringing in clustering and domain priors, thereby improving the performance of few-shot tuning. We have conducted extensive experiments on 11 common classification benchmarks. The results show our method significantly surpasses the original CLIP and achieves state-of-the-art (SOTA) performance under all benchmarks and settings. For example, under the 16-shot setting, our method exhibits a remarkable improvement over the original CLIP by 19.6%, and also surpasses TIP-Adapter and GraphAdapter by 2.7% and 2.2%, respectively, in terms of average accuracy across the 11 benchmarks. Code is available at https://github.com/uyzhang/Cluster-Adapter.

Silver nanoparticles induced synaptic degeneration via Ca2+/CaMKII signal and Drp1-dependent mitochondrial disorder in HT22 cells.

Silver nanoparticles (AgNPs) have been widely used in biomedicine and cosmetics, increasing their potential risks in neurotoxicity. But the involved molecular mechanism remains unclear. This study aims to explore molecular events related to AgNPs-induced neuronal damage by RNA-seq, and elucidate the role of Ca2+/CaMKII signal and Drp1-dependent mitochondrial disorder in HT22 cells synaptic degeneration induced by AgNPs. This study found that cell viabilities were decreased by AgNPs in a dose/time-dependent manner. AgNPs also increased protein expression of PINK1, Parkin, synaptophysin, and inhibited PGC-1α, MAP2 and APP protein expression, indicating AgNPs-induced synaptic degeneration involved in disturbance of mitophagy and mitochondrial biogenesis in HT22 cells. Moreover, inhibition of AgNPs-induced Ca2+/CaMKII activation and Drp1/ROS rescued mitophagy disturbance and synaptic degeneration in HT22 cells by reserving aforementioned protein express changes except for PGC-1α and APP protein. Thus, AgNPs-induced synaptic degeneration was mediated by Ca2+/CaMKII signal and Drp1-dependent mitochondrial disorder in HT22 cells, and mitophagy is the sensitive to the mechanism. Our study will provide in-depth molecular mechanism data for neurotoxic evaluation and biomedical application of AgNPs.

Oxidative stress-activated Nrf2 remitted polystyrene nanoplastic-induced mitochondrial damage and inflammatory response in HepG2 cells.

Generated from plastics, microplastics (MPs) and nanoplastics (NPs) are difficult to completely degrade in the natural environment, which can accumulate in almost all lives. Liver is one of the main target organs. In this study, HepG2 and L02 cells were exposed to 0-50 µg/mL polystyrene (PS)-NPs to investigate the mechanism of mitochondrial damage and inflammation. The results showed mitochondria damage and inflammatory caused by NPs, and it can be inhibited by N-acetyl-L-cysteine (NAC). In addition, reactive oxygen species (ROS) activated nuclear factor erythroid-derived factor 2-related factor (Nrf2) pathway. Nrf2 siRNA exacerbated the injury, suggesting Nrf2 plays a protective role. Moreover, p62 siRNA increased ROS and mitochondrial damage by inhibiting Nrf2, but didn't affect the inflammation. In conclusion, Nrf2 was activated by ROS and played a protective role in PS-NPs-mediated hepatotoxicity. This study supplemented the data of liver injury caused by PS-NPs, providing a basis for the safe disposal of plastics.

Beyond Self-Attention: External Attention Using Two Linear Layers for Visual Tasks.

Attention mechanisms, especially self-attention, have played an increasingly important role in deep feature representation for visual tasks. Self-attention updates the feature at each position by computing a weighted sum of features using pair-wise affinities across all positions to capture the long-range dependency within a single sample. However, self-attention has quadratic complexity and ignores potential correlation between different samples. This article proposes a novel attention mechanism which we call external attention, based on two external, small, learnable, shared memories, which can be implemented easily by simply using two cascaded linear layers and two normalization layers; it conveniently replaces self-attention in existing popular architectures. External attention has linear complexity and implicitly considers the correlations between all data samples. We further incorporate the multi-head mechanism into external attention to provide an all-MLP architecture, external attention MLP (EAMLP), for image classification. Extensive experiments on image classification, object detection, semantic segmentation, instance segmentation, image generation, and point cloud analysis reveal that our method provides results comparable or superior to the self-attention mechanism and some of its variants, with much lower computational and memory costs.

Study on Chain Extension Blending Modification and Foaming Behavior of Thermoplastic Polyamide Elastomer.

In order to improve the melt foaming properties of thermoplastic polyamide elastomers and reduce the shrinkage rate of foamed materials, acid anhydride chain extenders SMA (styrene maleic anhydride copolymer) are used in this paper to in situ reactive blending thermoplastic polyamide elastomers (TPAE) and polyamide 6 (PA6). The rheological and crystalline properties of the modified samples were characterized by a rotational rheometer and differential scanning calorimeter, and the melt batch foaming experiment with CO2 as the foaming agent was carried out. The results showed that the melting enthalpy of modified TPAE reduced with the addition of content of PA6, which implied that the crystallinity of the hard phase of the system was depressed. Nevertheless, the reduction of crystallinity was beneficial to improve the penetration of gas and reduce the effect of the pressure difference inside and outside the cell on foam shrinkage. Additionally, the microcross-linked structure formed with the increase of PA6 content enhanced the storage modulus of modified TPAE, which could accelerate recovery of strain. The foaming temperature zone and recovery performance of all modified TPAE samples were significantly improved. The overall shrinkage rate was reduced to less than 10%, the maximum expansion ratio could reach 11-13 times with a more complete and uniform cell structure, and the resilience was improved by about 12%.

Comparative oxidative damages induced by silver nanoparticles with different sizes and coatings in Caenorhabditis elegans.

Silver nanoparticles (AgNPs) are widely used in many commercial and medical products. Serious concerns are paid on their adverse potentials to the environment and human health. In this study, toxic effects and oxidative stress induced by AgNPs with different sizes and coatings (20 nm AgNPs, 20 nm polyvinylpyrrolidone (PVP) -AgNPs and 50 nm AgNPs) in Caenorhabditis elegans (C. elegans) were investigated. The toxic effects including the shortened lifespan and decreased frequency of head thrashes and body bends of C. elegans were induced in a dose-dependent manner by AgNPs. The reactive oxygen species (ROS) production and the oxidative stress-related indicators including malondialdehyde (MDA) and glutathione (GSH) in nematodes were changed after exposure to three kinds of AgNPs. These effects were the most obvious in a 20 nm PVP-AgNPs exposure group. AgNPs could also induce the expression of genes related to oxidative stress in nematodes. In addition, the up-regulation of mtl-1 and mtl-2 in nematodes might reduce the oxidative damage caused by AgNPs, by using transgenic strains CF2222 and CL2120 nematodes. Metallothionein (MT), an antioxidant, could relieve the oxidative damage caused by AgNPs. These results suggested that 20 nm PVP-AgNPs with a smaller particle size and better dispersion have stronger toxic effects and the oxidative damage to nematodes. Mtl-1 and mtl-2 might be involved in alleviating the oxidative damage caused by AgNPs. Our findings provide clues for the safety evaluation and mechanism information of metal nanoparticles.

Adaptive regulations of Nrf2 alleviates silver nanoparticles-induced oxidative stress-related liver cells injury.

Silver nanoparticles (AgNPs) are widely used in various fields such as industry, agriculture, and medical care because of their excellent broad-spectrum antibacterial activity. However, their extensive use has raised concerns about their health risks. Liver is one of the main target organs for the accumulation and action of AgNPs. Therefore, evaluating the toxic effects of AgNPs on liver cells and its mechanisms of action is crucial for the safe application of AgNPs. In the study, polyvinylpyrrolidone (PVP)-coated AgNPs were characterized. The human hepatoma cell line (HepG2) and the normal hepatic cell line (L02) were exposed to different concentrations of AgNPs (20-160 µg/mL) and pretreated with the addition of N-acetylcysteine (NAC) or by Nrf2 siRNA transfection. NAC was able to inhibit the concentration-dependent increase in the level of apoptosis induced by AgNPs in HepG2 cells and L02 cells. Interestingly, HepG2 cells were more sensitive to AgNPs than L02 cells, and this may be related to the different ROS generation and responses to AgNPs by cancer cells and normal cells. In addition, NAC also alleviated the imbalance of antioxidant system and cell cycle arrest, which may be related to AgNPs-induced DNA damage and autophagy. The knockdown of nuclear factor erythroid-derived factor 2-related factor (Nrf2) found that AgNPs-induced ROS and apoptosis levels were further upregulated, but the cell cycle arrest was alleviated. On the whole, Nrf2 exerts a protective role in AgNPs-induced hepatotoxicity. This study complements the hepatotoxicity mechanisms of AgNPs and provides data for a future exploration of AgNPs-related anti-hepatocellular carcinoma drugs.

ROS and DRP1 interactions accelerate the mitochondrial injury induced by polystyrene nanoplastics in human liver HepG2 cells.

Microplastics have become a serious environmental pollutant and subsequently have harmful effects on human health. Thus, the impacts of microplastics on human cells need to be explored. In the present study, the cytotoxic effects at the subcellular-organelle levels to polystyrene nanoplastics (PS-NPs, diameter 21.5 ± 2.7 nm) were investigated in the human hepatocellular carcinoma (HepG2) cell line. The cell viability exposed to PS-NPs at the concentrations of 6.25, 12.5, 25 and 50 µg/mL for 24 h diminished in a concentration-dependent manner. The PS-NPs treatment induced mitochondrial injuries, including morphological changes, decreased adenosine triphosphate (ATP) production and the loss of mitochondrial membrane potentials (MMP). The PS-NPs treatment could further spark cell apoptosis by upregulating caspase 3, caspase 9, cytochrome c, and Bcl-2 associated X protein (Bax)/B-cell lymphoma-2 (Bcl-2) in HepG2 cells, which is related to the mitochondrial dysfunction. PS-NPs exposure stimulated the excessive cellular reactive oxygen species (ROS) production and also induced mitochondrial fission by upregulating dynamin-related protein 1 (DRP1) and P-DRP1, but downregulating optic atrophy protein 1 (OPA1) and peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1α) expression levels. The above effects on mitochondria damage induced by PS-NPs were reversed by the pretreatment of N-acetylcysteine (NAC), mitochondrial division inhibitor 1 (Mdivi-1) and DRP1 siRNA. The results suggested that the interaction between ROS and DRP1-dependent mitochondrial division could promote mitochondrial lesions and mitochondria-related apoptosis caused by PS-NPs. These findings on molecular mechanisms provide a theoretical basis for preventing the hazards caused by microplastics to human health.