Arsenic or/and antimony induced mitophagy and apoptosis associated with metabolic abnormalities and oxidative stress in the liver of mice

Association of prenatal multiple metal exposures with child neurodevelopment at 3 years of age: A prospective birth cohort study

Prenatal exposures to toxic metals and trace elements have been linked to childhood neurodevelopment. However, existing evidence remains inconclusive, and further research is needed to investigate the mixture effects of multiple metal exposures on childhood neurodevelopment. We aimed to examine the associations between prenatal exposure to specific metals and metal mixtures and neurodevelopment in children. In this prospective cohort study, we used the multivariable linear regressions and the robust modified Poisson regressions to explore the associations of prenatal exposure to 25 specific metals with neurodevelopment among children at 3 years of age in 854 mother-child pairs from the Jiangsu Birth Cohort (JBC) Study. The Bayesian kernel machine regression (BKMR) was employed to assess the joint effects of multiple metals on neurodevelopment. Prenatal manganese (Mn) exposure was negatively associated with the risk of non-optimal cognition development of children, while vanadium (V), copper (Cu), zinc (Zn), antimony (Sb), cerium (Ce) and uranium (U) exposures were positively associated with the risk of non-optimal gross motor development. BKMR identified an interaction effect between Sb and Ce on non-optimal gross motor development. Additionally, an element risk score (ERS), representing the mixture effect of multiple metal exposures including V, Cu, Zn, Sb, Ce and U was constructed based on weights from a Poisson regression model. Children with ERS in the highest tertile had higher probability of non-optimal gross motor development (RR = 2.37, 95 % CI: 1.15, 4.86) versus those at the lowest tertile. Notably, Sb [conditional-posterior inclusion probabilities (cPIP) = 0.511] and U (cPIP = 0.386) mainly contributed to the increased risk of non-optimal gross motor development. The findings highlight the importance of paying attention to the joint effects of multiple metals on children's neurodevelopment. The ERS score may serve as an indicator of comprehensive metal exposure risk for children's neurodevelopment.

Selenium restored mitophagic flux to alleviate cadmium-induced hepatotoxicity by inhibiting excessive GPER1-mediated mitophagy activation

Cadmium (Cd) is a common environmental pollutant, while selenium (Se) can ameliorate heavy metal toxicity. Consequently, this study aimed to investigate the protective effects of Se against Cd-induced hepatocyte injury and its underlying mechanisms. To achieve this, we utilized the Dongdagou-Xinglong cohort, BRL3A cell models, and a rat model exposed to Cd and/or Se. The results showed that Se counteracted liver function injury and the decrease in GPER1 levels caused by environmental Cd exposure, and various methods confirmed that Se could protect against Cd-induced hepatotoxicity both in vivo and in vitro. Mechanistically, Cd caused excessive mitophagy activation, evidenced by the colocalization of LC3B, PINK1, Parkin, P62, and TOMM20. Transfection of BRL3A cells with mt-keima adenovirus indicated that Cd inhibited autophagosome-lysosome fusion, thereby impeding mitophagic flux. Importantly, G1, a specific agonist of GPER1, mitigated Cd-induced mitophagy overactivation and hepatocyte toxicity, whereas G15 exacerbates these effects. Notably, Se supplementation attenuated Cd-induced GPER1 protein reduction and excessive mitophagy activation while facilitating autophagosome-lysosome fusion, thereby restoring mitophagic flux. In conclusion, this study proposed a novel mechanism whereby Se alleviated GPER1-mediated mitophagy and promoted autophagosome-lysosome fusion, thus restoring Cd-induced mitophagic flux damage, and preventing hepatocyte injury.

Endocrine system, cell growth and death, and energy metabolism induced by Sb(III) exposure in earthworm (Pheretima guillemi) revealed by transcriptome and metabolome analysis

Antimony (Sb) is known for its severe and extensive toxicity, and earthworms are considered important indicator organisms in soil ecosystems. Therefore, the present study investigated the mechanism of toxicity of the Sb at different concentrations (50, 200 mg/kg) on earthworms using biochemical indicators, pathological sections, as well as metabolomics and transcriptomics analyses. The results showed that as the exposure concentration increased, both the antioxidant system of earthworms, extent of intestinal damage, and their metabolomic characteristics were significantly enhanced. In the 50 and 200 mg/kg Sb treatment group, 30 and 177 significant differentially changed metabolites (DCMs) were identified, respectively, with the most DCMs being down- and up-regulated, respectively. Metabolomics analysis showed that the contents of dl-tryptophan, glutamic acid, glycine, isoleucine, l-methionine, involved in the protein digestion and absorption as well as aminoacyl-tRNA biosynthesis were significantly up-regulated under the 200 mg/kg treatment. At the transcriptional level, Sb mainly affected the immune system, nervous system, amino acid metabolism, endocrine system, and carbohydrate metabolism in earthworms. The integration of transcriptomic and metabolomic data indicated that high doses of Sb regulated the metabolites and genes related to the oxidative phosphorylation pathway in earthworms. Overall, these results revealed global responses beyond the scope of conventional toxicity endpoints and facilitated a more in-depth and comprehensive assessment of the toxic effects of Sb.

Oral arsenite exposure induces inflammation and apoptosis in pulmonary tissue: acute and chronic evaluation in young and adult mice

Inorganic arsenic is a well-known environmental toxicant, and exposure to this metalloid is strongly linked with severe and extensive toxic effects in various organs including the lungs. In the present study, we aimed to investigate the acute and chronic effects of arsenite exposure on pulmonary tissue in young and adult mice. In brief, young and adult female Balb/C mice were exposed to 3 and 30 ppm arsenite daily via drinking water for 30 and 90 days. Subsequently, the animals were sacrificed and various histological and immunohistochemistry (IHC) analyses were performed using lung tissues. Our findings showed arsenite was found to cause dose-dependent pathological changes such as thickening of the alveolar septum, inflammatory cell infiltrations and lung fibrosis in young and adult mice. In addition, arsenite exposure significantly increased the expression of inflammatory markers NF-κB and TNF-α, indicating that arsenite-exposed mice suffered from severe lung inflammation. Moreover, the IHC analysis of fibrotic proteins demonstrated an increased expression of TGF-β1, α-SMA, vimentin and collagen-I in the arsenite-exposed mice compared to the control mice. This was accompanied by apoptosis, which was indicated by the upregulated expression of caspase-3 in arsenite-exposed mice compared to the control. Adult mice were generally found to be more prone to arsenite toxicity during chronic exposure relative to their younger counterparts. Overall, our findings suggest that arsenite in drinking water may induce dose-dependent and age-dependent structural and functional impairment in the lungs through elevating inflammation and fibrotic proteins.

Curcumin attenuates aflatoxin B1-induced ileum injury in ducks by inhibiting NLRP3 inflammasome and regulating TLR4/NF-κB signaling pathway

Aflatoxin B1 (AFB1) is a widespread toxic contamination in feed for animals. The primary active component of turmeric, curcumin (Cur), is an antioxidant and an anti-inflammatory. However, it is yet unknown how AFB1 affects the intestinal epithelial barrier and whether Cur acts as a protective mechanism when exposed to AFB1. Here, we explored the mechanism of AFB1-induced intestinal injury from intestinal epithelial barrier, inflammation, pyroptosis, and intestinal flora, and evaluated the protective role of Cur. We found that AFB1 caused weight loss and intestinal morphological damage that is mainly characterized by shortened intestinal villi, deepened crypts, and damaged intestinal epithelium. Exposure to AFB1 decreased the expression of Claudin-1, MUC2, ZO-1, and Occludin and increased the expression of pyroptosis-related factors (NLRP3, GSDMD, Caspase-1, IL-1β, and IL-18) and inflammation-related factors (TLR4, NF-κB, IκB, IFN-γ, and TNF-α). Furthermore, ileal gut microbiota was altered, and simultaneously, the Lactobacillus abundance was decreased. The gut microbiota interacts with a wide range of physiologic functions and disease development in the host through its metabolites, and disturbances in gut microbial metabolism can cause functional impairment of the ileum. Meanwhile, Cur can ameliorate histological ileum injuries and intestinal flora disturbance caused by AFB1. We found that Cur reversed the effects of AFB1 through modulating both NLRP3 inflammasome and the TLR4/NF-κB signaling pathway. In conclusion, AFB1 can induce inflammatory damage and pyroptosis in duck ileum, while Cur has obviously protective effects on all the above damages.

Mediating Role of Liver Dysfunction in the Association between Arsenic Exposure and Diabetes in Chinese Adults: A Nationwide Cross-Sectional Study of China National Human Biomonitoring (CNHBM) 2017-2018

Inconsistent results have been reported regarding the association between low-to-moderate arsenic (As) exposure and diabetes. The effect of liver dysfunction on As-induced diabetes remains unclear. The cross-sectional study included 10,574 adults from 2017-2018 China National Human Biomonitoring. Urinary total As (TAs) levels were analyzed as markers of As exposure. Generalized linear mixed models and restricted cubic splines models were used to examine the relationships among TAs levels, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentrations, and diabetes prevalence. Mediating analysis was performed to assess whether liver dysfunction mediated the association between TAs and diabetes. Overall, the OR (95% CI) of diabetes in participants in the second, third, and fourth quartiles of TAs were 1.08 (0.88, 1.33), 1.17 (0.94, 1.45), and 1.52 (1.22, 1.90), respectively, in the fully adjusted models compared with those in the lowest quartile. Serum ALT was positively associated with TAs and diabetes. Additionally, mediation analyses showed that ALT mediated 4.32% of the association between TAs and diabetes in the overall population and 8.86% in the population without alcohol consumption in the past year. This study suggested that alleviating the hepatotoxicity of As could have implications for both diabetes and liver disease.

Multi-omics reveals the protective effects of curcumin against AFB1-induced oxidative stress and inflammatory damage in duckling intestines

Aflatoxin B1 (AFB1) is the most prevalent and toxic class of aflatoxins, which is considered a significant risk factor for food safety. Curcumin, a phytoconstituent with anti-inflammatory and antioxidant properties, has potential therapeutic value for intestinal inflammatory diseases. In this study, the duckling model susceptible to AFB1 was selected for toxicity testing, aiming to explore the effect of curcumin on AFB1 enterotoxicity and its possible mechanism of action. The results showed that curcumin promoted the growth and development of ducklings and mitigated the changes in morphology and permeability serological index (DAO and D-LA) after AFB1 exposure. Curcumin also mitigated AFB1-induced oxidative stress by activating the Nrf2 pathway, and ameliorated intestinal inflammation by inhibiting the NF-κB/IκB signaling pathway and boosting intestinal autophagy. In terms of gut flora and their metabolites, we found that curcumin supplementation significantly increased the intestinal flora's abundance index and diversity index compared to the AFB1 group, mitigating the decline in the abundance of Actinobacteria and the rise in that of harmful bacteria Clostridia. Furthermore, untargeted metabolomic analysis revealed that the protective effect of curcumin on the intestine was mainly through the regulation of AFB1-induced disorders of lipid metabolism, involving linoleic acid metabolism, α-linolenic acid metabolism, and glycerolipid metabolism. Overall, the enteroprotective effects of curcumin may be of significant value in the future for treating chronic AFB1 poisoning and also provide new therapeutic ideas for other mycotoxicosis.

Environment, Endocrine Disruptors, and Fatty Liver Disease Associated with Metabolic Dysfunction (MASLD)

Ecological theories suggest that environmental factors significantly influence obesity risk and related syndemic morbidities, including metabolically abnormal obesity associated with nonalcoholic fatty liver disease (MASLD). These factors encompass anthropogenic influences and endocrine-disrupting chemicals (EDCs), synergistically interacting to induce metabolic discrepancies, notably in early life, and disrupt metabolic processes in adulthood. This review focuses on endocrine disruptors affecting a child's MASLD risk, independent of their role as obesogens and thus regardless of their impact on adipogenesis. The liver plays a pivotal role in metabolic and detoxification processes, where various lipophilic endocrine-disrupting molecules accumulate in fatty liver parenchyma, exacerbating inflammation and functioning as new anthropogenics that perpetuate chronic low-grade inflammation, especially insulin resistance, crucial in the pathogenesis of MASLD.

MitomiR-1736-3p regulates copper-induced mitochondrial pathway apoptosis by inhibiting AATF in chicken hepatocytes

Copper (Cu) is a toxic heavy metal pollutant. The hepatic toxicity of Cu has attracted widespread attention from researchers. However, its underlying mechanism remains elusive. Mitochondrial microRNAs (mitomiRs) are considered important factors in regulating mitochondrial and cellular functions, and their roles have been implicated in the mechanisms of metal toxicity. Therefore, this research revealed the changes in the mitomiRs expression profile of chicken liver after Cu exposure. It was ultimately determined that mitomiR-1736-3p can be involved in Cu-induced chicken liver damage by targeting AATF. In particular, our investigations have uncovered that exposure to Cu can trigger heightened levels of apoptosis in the hepatic tissue of chickens and primary chicken embryo hepatocytes (CEHs). It is noteworthy that we found upregulation of miR-1736-3p expression can exacerbate Cu-induced cell apoptosis, while inhibition of miR-1736-3p can effectively reduce apoptosis occurrence. Subsequently, we found that Cu-induced cell apoptosis could be restored by overexpressing AATF, while silencing AATF exacerbated the level of apoptosis. Fascinatingly, this change in apoptotic level is directly influenced by AATF on Bax and Bak1, rather than on p53 and Bcl-2. Overall, these findings suggest that the mitomiR-1736-3p/AATF axis mediates the mitochondrial pathway of cell apoptosis potentially involved in Cu-induced chicken liver toxicity.

Arsenic and polystyrene-nano plastics co-exposure induced testicular toxicity: Triggers oxidative stress and promotes apoptosis and inflammation in mice

Co-existing of polystyrene-nano plastics (PSNPs) and arsenic (As) in the environment caused a horrendous risk to human health. However, the potential mechanism of PSNPs and As combination induced testicular toxicity in mammals has not been elucidated. Therefore, we first explore the testicular toxicity and the potential mechanism in male Kunming mice exposed to As or/and PSNPs. Results revealed that compared to the As or PSNPs group, the combined group showed more significant testicular toxicity. Specifically, As and PSNPs combination induced irregular spermatozoa array and blood-testis barrier disruption. Simultaneously, As and PSNPs co-exposure also exacerbated oxidative stress, including increasing the MDA content, and down-regulating expression of Nrf-2, HO-1, SOD-1, and Trx. PSNPs and As combination also triggered testicular apoptosis, containing changes in apoptotic factors (P53, Bax, Bcl-2, Cytc, Caspase-8, Caspase-9, and Caspase-3). Furthermore, co-exposed to As and PSNPs aggravated inflammatory damage characterized by targeted phosphorylation of NF-κB and degradation of I-κB. In summary, our results strongly confirmed As + PSNPs co-exposure induced the synergistic toxicity of testis through excessive oxidative stress, apoptosis, and inflammation, which could offer a new sight into the mechanism of environmental pollutants co-exposure induced male reproductive toxicity.

Understanding the goethite role on stibnite oxidative dissolution and transformation: Spectroscopic and DFT study

The geochemical cycling of antimony (Sb) in aquatic system is primarily influenced by the dissolution and transformation of stibnite (Sb2S3) in the presence of iron minerals. Here, Sb2S3 oxidative dissolution and sequestration on goethite were investigated to mimic the environmental fate of Sb2S3. The results demonstrated that goethite accelerated the rate of Sb2S3 oxidative dissolution by a factor of 9.4 times under sunlight. The significant Sb2S3 oxidation on goethite was attributed to a heterogeneous electron transfer from Sb2S3 to goethite, as proved by XANES analysis. This electron transfer facilitated the generation of hydroxyl radicals (OH) on Sb2S3, and superoxide radicals (O2-) on goethite. Radical trapping experiments confirmed that O2- was the dominant oxidant for Sb(III) oxidation with 91 % contribution. Thus, goethite plays a dominant role in O2- generation and Sb2S3 oxidative dissolution. Meanwhile, the total dissolved Sb was decreased by 69 % in Sb2S3 and goethite coexisting system compared to a single Sb2S3 system, indicating the retention of dissolved Sb on goethite. Density functional theory (DFT) calculations deciphered that Sb(III) oxidation on mineral-water interfaces with O2- radicals was thermodynamically preferential to OH radicals. Additionally, the Sb was anchored on goethite as a bidentate binuclear structure with a favorable adsorption energy. Our findings shed the light to understand the geochemical cycles of Sb2S3 in natural environment.

Arsenic-Induced Ferroptosis in Chicken Hepatocytes via the Mitochondrial ROS Pathway

Arsenic has been shown to be highly toxic and can cause liver damage. Previous studies have shown that arsenic causes severe liver damage and induces accumulation of reactive oxygen species (ROS). This study aimed to investigate the effects of ferroptosis on the liver in arsenic trioxide (ATO) and to explore the underlying mechanisms. We confirmed the hepatotoxic effects of arsenic by in vivo and in vitro experiments. After 28 days of administration of arsenic trioxide (4-mg/kg, 8-mg/kg) by gavage, chickens exhibited body weight loss and liver damage in a dose-dependent manner. In addition, in vivo and in vitro western blot and real-time fluorescence quantitative PCR analyses simultaneously indicated that ferroptosis might be the main pathway of arsenic-induced liver injury. Finally, Mito-TEMPO effectively eliminated the ROS accumulation in mitochondria, significantly attenuating the process of cellular ferroptosis. In summary, the hepatotoxic effects of arsenic are related to ferroptosis, and the hepatic ferroptosis process of arsenic is regulated by mitochondrial ROS (MtROS). Our study reveals new mechanisms of arsenic toxicity to the liver, which may deepen our understanding of arsenic toxicology.

Association of urinary arsenic metabolism with type 2 diabetes and glucose homeostasis: Cross-sectional and longitudinal associations

BACKGROUND

Previous researches have assessed the relationships of urinary arsenic metabolism with type 2 diabetes (T2D) and glucose-insulin homeostasis, but the results were controversial, and potential mechanisms remain largely unclear.

OBJECTIVES

This study aimed to investigate the cross-sectional and longitudinal associations of urinary arsenic metabolism with T2D prevalence and glucose changes in relatively higher arsenic exposure, and further to evaluate the underlying roles of oxidative damage in these relationships.

METHODS

We included 796 participants at baseline, among them 509 participants were followed up after 2 years. Logistic regression model and leave-one-out approach were applied to evaluate the associations of arsenic metabolism with T2D prevalence. Linear mixed model was conducted to estimate the relationship of arsenic metabolism with glycemic changes over two years. The associations between arsenic metabolism and indicators of oxidative stress were assessed with a linear regression model. We further performed mediation analysis to investigate the role of oxidative stress in the associations of arsenic metabolism with 2-year change of glucose levels.

RESULTS

Higher urinary MMA% increased T2D prevalence and baseline glucose levels. MMA% was positively associated with 2-year change of glucose levels. Moreover, we observed significant dose-response relationship between MMA% and 8-hydroxy-2-deoxyguanosine (8-OHdG). However, the mediating role of 8-OHdG in the association of MMA% and 2-year change of glucose levels was not observed in this population.

CONCLUSIONS

In this population exposure to relatively higher arsenic levels, higher MMA% contributed to increased T2D prevalence and glucose homeostasis disorder. Arsenic metabolism also affected oxidative stress levels, especially 8-OHdG. Further studies are required to investigate the potential mechanisms.

The Role of BNIP3 and Blocked Autophagy Flux in Arsenic-Induced Oxidative Stress-Induced Liver Injury in Rats

Arsenic is a widely distributed environmental toxic substance in nature. Chronic arsenic exposure can cause permanent damage to the liver, resulting in the death of poisoned patients. However, the mechanism of liver damage caused by arsenic poisoning is yet unclear. Here, four different concentrations of sodium arsenite (NaAsO2) (0 mg/L (control group), 25 mg/L, 50 mg/L, and 100 mg/L group)were established to induce liver injury in rats. Taking this into account, the relationship and potential mechanisms of oxidative stress, Bcl-2/adenovirus E1B-19-kDa-interacting protein 3 (BNIP3), and inhibition of autophagy flux in liver injury caused by arsenic poisoning were studied. The results indicated that long-term exposure to NaAsO2 could induce oxidative stress, leading to high expression of BNIP3, thereby impaired autophagy flux, and ultimately resulting in liver damage. This research provides an important basis for future research on liver damage caused by chronic arsenic exposure and prevention and treatment with BNIP3 as the target.

Dissecting the role of cadmium, lead, arsenic, and mercury in non-alcoholic fatty liver disease and non-alcoholic steatohepatitis

The objective of the present study was to review the existing epidemiological and laboratory findings supporting the role of toxic metal exposure in non-alcoholic fatty liver disease (NAFLD). The existing epidemiological studies demonstrate that cadmium (Cd), lead (Pb), arsenic (As), and mercury (Hg) exposure was associated both with an increased risk of NAFLD and altered biochemical markers of liver injury. Laboratory studies demonstrated that metal exposure induces hepatic lipid accumulation resulting from activation of lipogenesis and inhibition of fatty acid β-oxidation due to up-regulation of sterol regulatory element-binding protein 1 (SREBP-1), carbohydrate response element binding protein (ChREBP), peroxisome proliferator-activated receptor γ (PPARγ), and down-regulation of PPARα. Other metabolic pathways involved in this effect may include activation of reactive oxygen species (ROS)/extracellular signal-regulated kinase (ERK) and inhibition of AMP-activated protein kinase (AMPK) signaling. The mechanisms of hepatocyte damage during development of metal-induced hepatic steatosis were shown to involve oxidative stress, endoplasmic reticulum stress, pyroptosis, ferroptosis, and dysregulation of autophagy. Induction of inflammatory response contributing to progression of NAFLD to non-alcoholic steatohepatitis (NASH) upon toxic metal exposure was shown to be mediated by up-regulation of nuclear factor κB (NF-κB) and activation of NRLP3 inflammasome. Moreover, epigenetic effects of the metals, as well as their effect on gut microbiota and gut wall integrity were also shown to mediate their role in NAFLD development. Despite being demonstrated for Cd, Pb, and As, the contribution of these mechanisms into Hg-induced NAFLD is yet to be estimated. Therefore, further studies are required to clarify the intimate mechanisms underlying the relationship between heavy metal and metalloid exposure and NAFLD/NASH to reveal the potential targets for treatment and prevention of metal-induced NAFLD.

Altered generation pattern of reactive oxygen species triggering DNA and plasma membrane damages to human liver cells treated with arsenite

Human exposure to arsenic via drinking water is one of globally concerned health issues. Oxidative stress is regarded as the denominator of arsenic-inducing toxicities. Therefore, to identify intracellular sources of reactive oxygen species (ROS) could be essential for addressing the detrimental effects of arsenite (iAsIII). In this study, the contributions of different pathways to ROS formation in iAsIII-treated human normal liver (L-02) cells were quantitatively assessed, and then concomitant oxidative impairs were evaluated using metabolomics and lipidomics approaches. Following iAsIII treatment, NADPH oxidase (NOX) activity and expression levels of p47phox and p67phox were upregulated, and NOX-derived ROS contributed to almost 60.0 % of the total ROS. Moreover, iAsIII also induced mitochondrial superoxide anion and impaired mitochondrial respiratory function of L-02 cells with a decreasing ATP production. The inhibition of NOX activity significantly rescued mitochondrial membrane potential in iAsIII-treated L-02 cells. Purine and glycerophospholipids metabolisms in L-02 cells were disrupted by iAsIII, which might be used to represent DNA and plasma membrane damages, respectively. Our study supported that NOX could be the primary pathway of ROS overproduction and revealed the potential mechanisms of iAsIII toxicity related to oxidative stress.

A Drosophila model of gestational antimony exposure uncovers growth and developmental disorders caused by disrupting oxidative stress homeostasis

The toxic heavy metal antimony (Sb) is ubiquitous in our daily lives. Various models have shown that Sb induces neuronal and reproductive toxicity. However, little is known about the developmental toxicity of Sb exposure during gestation and the underlying mechanisms. To study its effects on growth and development, Drosophila stages from eggs to pupae were exposed to different Sb concentrations (0, 0.3, 0.6 and 1.2 mg/mL Sb); RNA sequencing was used to identify the underlying mechanism. The model revealed that prenatal Sb exposure significantly reduced larval body size and weight, the pupation and eclosion rates, and the number of flies at all stages. With 1.2 mg/mL Sb exposure in 3rd instar larvae, 484 genes were upregulated and 694 downregulated compared to controls. Biological analysis showed that the disrupted transcripts were related to the oxidative stress pathway, as verified by reactive oxygen species (ROS) scavenger N-acetylcysteine (NAC) and glutathione (GSH) intervention experiments. Sb exposure induced oxidative stress imbalance could be rectified by chelation and antioxidant effects of NAC/GSH. The Drosophila Schneider 2 (S2) model further demonstrated that NAC and GSH greatly ameliorated cell death induced by Sb exposure. In conclusion, gestational Sb exposure disrupted oxidative stress homeostasis, thereby impairing growth and development.

Refining health risk assessment of arsenic in wild edible boletus from typical high geochemical background areas: The role of As species, bioavailability, and enterotoxicity

Arsenic (As) is easily accumulated in wild Boletus. However, the accurate health risks and adverse effects of As on humans were largely unknown. In this study, we analyzed the total concentration, bioavailability, and speciation of As in dried wild boletus from some typical high geochemical background areas using an in vitro digestion/Caco-2 model. The health risk assessment, enterotoxicity, and risk prevention strategy after consumption of As-contaminated wild Boletus were further investigated. The results showed that the average concentration of As was 3.41-95.87 mg/kg dw, being 1.29-56.3 folds of the Chinese food safety standard limit. DMA and MMA were the dominant chemical forms in raw and cooked boletus, while their total (3.76-281 mg/kg) and bioaccessible (0.69-153 mg/kg) concentrations decreased to 0.05-9.27 mg/kg and 0.01-2.38 mg/kg after cooking. The EDI value of total As was higher than the WHO/FAO limit value, while the bioaccessible or bioavailable EDI suggested no health risks. However, the intestinal extracts of raw wild boletus triggered cytotoxicity, inflammation, cell apoptosis, and DNA damage in Caco-2 cells, indicating existing health risk assessment models based on total, bioaccessible, or bioavailable As may be not accurate enough. Given that, the bioavailability, species, and cytotoxicity should be systematically considered in accurate risk assessment. In addition, cooking mitigated the enterotoxicity along with decreasing the total and bioavailable DMA and MMA in wild boletus, suggesting that cooking could be a simple and effective way to decrease the health risks of consumption of As-contaminated wild boletus.

Co-exposure to environmentally relevant concentrations of cadmium and polystyrene nanoplastics induced oxidative stress, ferroptosis and excessive mitophagy in mice kidney

Nanoplastics (NPs) are defined as a group of emerging pollutants. However, the adverse effect of NPs and/or heavy metals on mammals is still largely unclear. Therefore, we performed a 35-day chronic toxicity experiment with mice to observe the impacts of exposure to Cadmium (Cd) and/or polystyrene nanoplastics (PSNPs). This study revealed that combined exposure to Cd and PSNPs added to the mice's growth toxicity and kidney damage. Moreover, Cd and PSNPs co-exposure obviously increased the MDA level and expressions of 4-HNE and 8-OHDG while decreasing the activity of antioxidase in kidneys via inhibiting the Nrf2 pathway and its downstream genes and proteins expression. More importantly, the results suggested for the first time that Cd and PSNPs co-exposure synergistically increased iron concentration in kidneys, and induced ferroptosis through regulating expression levels of SLC7A11, GPX4, PTGS2, HMGB1, FTH1 and FTL. Simultaneously, Cd and PSNPs co-exposure further increased the expression levels of Pink, Parkin, ATG5, Beclin1, and LC3 while significantly reducing the P62 expression level. In brief, this study found that combined exposure to Cd and PSNPs synergistically caused oxidative stress, ferroptosis and excessive mitophagy ultimately aggravating kidney damage in mice, which provided new insight into the combined toxic effect between heavy metals and PSNPs on mammals.

Mitochondrial miR-12294-5p regulated copper-induced mitochondrial oxidative stress and mitochondrial quality control imbalance by targeted inhibition of CISD1 in chicken livers

Copper (Cu) is hazardous metal contaminant, which induced hepatotoxicity is closely related to mitochondrial disorder, but exact regulatory mechanism has not yet been revealed. Mitochondrial microRNAs (mitomiRs) are a novel and critical regulator of mitochondrial function and mitochondrial homeostasis. Hence, this study revealed the impact of Cu-exposure on mitomiR expression profiles in chicken livers, and further identified mitomiR-12294-5p and its target gene CISD1 as core regulators involved in Cu-induced hepatotoxicity. Additionally, our results showed that Cu-exposure induced mitochondrial oxidative damage, and mitochondrial quality control imbalance mediated by mitochondrial dynamics disturbances, mitochondrial biogenesis inhibition and abnormal mitophagy flux in chicken livers and primary chicken embryo hepatocytes (CEHs). Meaningfully, we discovered that inhibition of the expression of mitomiR-12294-5p effectively alleviated Cu-induced mitochondrial oxidative stress and mitochondrial quality control imbalance, while the up-regulation of mitomiR-12294-5p expression exacerbated Cu-induced mitochondrial damage. Simultaneously, the above Cu-induced mitochondrial damage can be effectively rescued by the overexpression of CISD1, while knockdown of CISD1 dramatically reverses the mitigating effect that inhibition of mitomiR-12294-5p expression on Cu-induced mitochondrial oxidative stress and mitochondrial quality control imbalance. Overall, these results suggested that mitomiR-12294-5p/CISD1 axis mediated mitochondrial damage is a novel molecular mechanism involved in regulating Cu-induced hepatotoxicity in chickens.

Recent insights into autophagy and metals/nanoparticles exposure

Some anthropogenic pollutants, such as heavy metals and nanoparticles (NPs), are widely distributed and a major threat to environmental safety and public health. In particular, lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As), and mercury (Hg) have systemic toxicity even at extremely low concentrations, so they are listed as priority metals in relation to their significant public health burden. Aluminum (Al) is also toxic to multiple organs and is linked to Alzheimer's disease. As the utilization of many metal nanoparticles (MNPs) gradually gain traction in industrial and medical applications, they are increasingly being investigated to address potential toxicity by impairing certain biological barriers. The dominant toxic mechanism of these metals and MNPs is the induction of oxidative stress, which subsequently triggers lipid peroxidation, protein modification, and DNA damage. Notably, a growing body of research has revealed the linkage between dysregulated autophagy and some diseases, including neurodegenerative diseases and cancers. Among them, some metals or metal mixtures can act as environmental stimuli and disturb basal autophagic activity, which has an underlying adverse health effect. Some studies also revealed that specific autophagy inhibitors or activators could modify the abnormal autophagic flux attributed to continuous exposure to metals. In this review, we have gathered recent data about the contribution of the autophagy/mitophagy mediated toxic effects and focused on the involvement of some key regulatory factors of autophagic signaling during exposure to selected metals, metal mixtures, as well as MNPs in the real world. Besides this, we summarized the potential significance of interactions between autophagy and excessive reactive oxygen species (ROS)-mediated oxidative damage in the regulation of cell survival response to metals/NPs. A critical view is given on the application of autophagy activators/inhibitors to modulate the systematic toxicity of various metals/MNPs.

Effects of antimony exposure on DNA damage and genome-wide variation in zebrafish (Danio rerio) liver

Antimony (Sb) is a potentially toxic and carcinogenic cumulative contaminant that poses a serious threat to aquatic ecosystems. To better clarify the genotoxicity of Sb and its mechanism of action. In this study, we investigated DNA damage and genome-wide variation in the liver of a model organism, zebrafish (Danio rerio), under subacute Sb exposure and explored its potential toxicological mechanisms. The results showed that medium and high concentrations of Sb significantly reduced the total antioxidant capacity and increased the content of reactive oxygen species in zebrafish liver, and further studies revealed that it increased oxidative DNA damage and DNA-DNA cross-link (DDC), but had little effect on DNA-protein cross-link (DPC). The result of resequencing showed that the mutation sites of the genes with high concentrations of Sb were higher than those with medium concentrations, and the mutation was mainly a single nucleotide. The pathways significantly enriched for nonsynonymous single nucleotide polymorphisms (SNPs) and insertion/deletion mutations (InDels) variant genes in the coding regions of both the medium and high Sb-treated groups were ECM-receptor interactions, and the high Sb-treated group also included lysine degradation, hematopoietic cell lineage, and cytokine-cytokine receptor interactions. This suggests that ECM-receptor interactions play an important role in the mechanism of antimony toxicity to the liver of zebrafish.

Regulation of Gut Microflora by Lactobacillus casei Zhang Attenuates Liver Injury in Mice Caused by Anti-Tuberculosis Drugs

The gut-liver axis may provide a new perspective for treating anti-tuberculosis drug-induced liver injury (ATDILI). Herein, the protective effect of Lactobacillus casei (Lc) was investigated by modulating gut microflora (GM) and the toll like receptor 4 (TLR4)-nuclear factor (NF)-κB-myeloiddifferentiationfactor 88 (MyD88) pathway. C57BL/6J mice were given three levels of Lc intragastrically for 2 h before administering isoniazid and rifampicin for 8 weeks. Blood, liver, and colon tissues, as well as cecal contents, were collected for biochemical and histological examination, as well as Western blot, quantitative real time polymerase chain reaction (qRT-PCR), and 16S rRNA analyses. Lc intervention decreased alkaline phosphatase (ALP), superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), and tumor necrosis factor (TNF)-α levels (p < 0.05), recovered hepatic lobules, and reduced hepatocyte necrosis to alleviate liver injury induced by anti-tuberculosis drugs. Moreover, Lc also increased the abundance of Lactobacillus and Desulfovibrio and decreased Bilophila abundance, while enhancing zona occludens (ZO)-1 and claudin-1 protein expression compared with the model group (p < 0.05). Furthermore, Lc pretreatment reduced the lipopolysaccharide (LPS) level and downregulated NF-κB and MyD88 protein expression (p < 0.05), thus restraining pathway activation. Spearman correlation analysis indicated that Lactobacillus and Desulfovibrio were positively correlated with ZO-1 or occludin protein expression and negatively correlated with pathway protein expression. Desulfovibrio had significant negative relationships with alanine aminotransferase (ALT) and LPS levels. In contrast, Bilophila had negative associations with ZO-1, occludin, and claudin-1 protein expressions and positive correlations with LPS and pathway proteins. The results prove that Lactobacillus casei can enhance the intestinal barrier and change the composition of the gut microflora. Moreover, Lactobacillus casei may also inhibit TLR4-NF-κB-MyD88 pathway activation and alleviate ATDILI.

Short-term exposure to antimony induces hepatotoxicity and metabolic remodeling in rats

Antimony (Sb) poses a significant threat to human health due to sharp increases in its exploitation and application globally, but few studies have explored the pathophysiological mechanisms of acute hepatotoxicity induced by Sb exposure. We established an in vivo model to comprehensively explore the endogenous mechanisms underlying liver injury induced by short-term Sb exposure. Adult female and male Sprague-Dawley rats were orally administrated various concentrations of potassium antimony tartrate for 28 days. After exposure, the serum Sb concentration, liver-to-body weight ratio, and serum glucose levels significantly increased in a dose-dependent manner. Body weight gain and serum concentrations of biomarkers of hepatic injury (e.g., total cholesterol, total protein, alkaline phosphatase, and the aspartate aminotransferase/alanine aminotransferase ratio) decreased with increasing Sb exposure. Through integrative non-targeted metabolome and lipidome analyses, alanine, aspartate, and glutamate metabolism; phosphatidylcholines; sphingomyelins; and phosphatidylinositols were the most significantly affected pathways in female and male rats exposed to Sb. Additionally, correlation analysis showed that the concentrations of certain metabolites and lipids (e.g., deoxycholic acid, N-methylproline, palmitoylcarnitine, glycerophospholipids, sphingomyelins, and glycerol) were significantly associated with hepatic injury biomarkers, indicating that metabolic remodeling may be involved in apical hepatotoxicity. Our study demonstrated that short-term exposure to Sb induces hepatotoxicity, possibly through a glycolipid metabolism disorder, providing an important reference for the health risks of Sb pollution.

Sodium arsenite-induced cytotoxicity is regulated by BNIP3L/Nix-mediated endoplasmic reticulum stress responses and CCPG1-mediated endoplasmic reticulum-phagy

We elucidated the BNIP3L/Nix and SQSTM1/p62 molecular mechanisms in sodium arsenite (NaAR)-induced cytotoxicity. Considerable changes in the morphology and adhesion of H460 cells were observed in response to varying NaAR concentrations. NaAR exposure induced DNA damage-mediated apoptosis and Nix accumulation via proteasome inhibition. Nix targets the endoplasmic reticulum (ER), inducing ER stress responses. p62 and Nix were colocalized and their expressions were inversely correlated. Autophagy inhibition upregulated Nix, p62, cell cycle progression gene 1 (CCPG1), heme oxygenase (HO)- 1, and calnexin expression. Nix knockdown decreased the NaAR-induced ER stress and microtubule-associated protein 1 A/1B light-chain 3 (LC3) B-II levels and increased the CCPG1 and calnexin levels. p62 knockdown upregulated Nix, LC3-II, and CCPG1 expressions and the ER stress responses, indicating that p62 regulates Nix levels. Nix downstream pathways were mitigated by Ca²⁺ chelators. We demonstrate the critical roles of Nix and p62 in ER stress and ER-phagy in response to NaAR.

Cuproptosis is involved in copper-induced hepatotoxicity in chickens

Copper (Cu) is an essential trace element, but it is also a ubiquitous environmental pollutant that threatens public health. Cuproptosis is a recently discovered cell death mode that unlike other programmed cell death, characterized by proteotoxic stress due to lipoylated protein aggregation and iron-sulfur cluster protein loss. Chickens as a high-trophic-level non-mammalian vertebrate that easily absorb and accumulate copper from the environment and food, but it is unclear whether the underlying molecular mechanisms that cause their hepatotoxicity under natural copper stress are related to cuproptosis. Therefore, we established animal models of chickens with different concentrations of copper exposure to dissect the role and mechanism of cuproptosis in chicken hepatotoxicity under natural copper stress. Our histopathological and biochemical results demonstrated that the liver structure with copper-treated exhibited dose-dependent damage. Meanwhile, copper treatment also dramatically increased serum and liver copper content and activated the expression of the membrane-associated copper transporter ATP7B. Furthermore, we found that Cu-exposure significantly increased the MDA content, and reduced the levels of T-AOC and SOD in serum and liver. Additionally, we found that the mRNA and protein levels of FDX1 were significantly upregulated in the 220 and 330 mg/kg Cu-treated groups. In our further studies, we found that copper did not alter protein levels of DLAT and DLST in chicken liver, but significantly increased Lipoylated-DLAT levels and oligomerization of Lipoylated-DLAT in the 330 mg/kg Cu-treatment group. Overall, we identified that FDX1-mediated protein lipoylation and proteotoxic stress indeed participate in copper-induced hepatotoxicity in chickens. Our results present novel insight into the pathogenesis of copper-induced hepatotoxicity in chickens and provide data to support filling in the role of cuproptosis in birds.

Systematic evaluation of membrane-camouflaged nanoparticles in neutralizing Clostridium perfringens ε-toxin

Clostridium perfringens ε-toxin (ETX) is the main toxin leading to enterotoxemia of sheep and goats and is classified as a potential biological weapon. In addition, no effective treatment drug is currently available in clinical practice for this toxin. We developed membrane-camouflaged nanoparticles (MNPs) with different membrane origins to neutralize ETX and protect the host from fatal ETX intoxication. We evaluated the safety and therapeutic efficacy of these MNPs in vitro and in vivo. Compared with membranes from karyocytes, such as Madin-Darby canine kidney (MDCK) cells and mouse neuroblastoma N2a cells (N2a cells), membrane from erythrocytes, which do not induce any immune response, are superior in safety. The protective ability of MNPs was evaluated by intravenous injection and lung delivery. We demonstrate that nebulized inhalation is as safe as intravenous injection and that both modalities can effectively protect mice against ETX. In particular, pulmonary delivery of nanoparticles more effectively treated the challenge of inhaled toxins than intravenously injected nanoparticles. Moreover, MNPs can alter the biological distribution of ETX among different organs in the body, and ETX was captured, neutralized and slowly delivered to the liver and spleen, where nanoparticles with ETX could be phagocytized and metabolized. This demonstrates how MNPs treat toxin infections in vivo. Finally, we injected the MNPs into mice in advance to find out whether MNPs can provide preventive protection, and the results showed that the long-cycle MNPs could provide at least a 3-day protection in mice. These findings demonstrate that MNPs provide safe and effective protection against ETX intoxication, provide new insights into membrane choices and delivery routes of nanoparticles, and new evidence of the ability of nanoparticles to provide preventive protection against infections.

Statins as Potential Preventative Treatment of ETX and Multiple Pore-Forming Toxin-Induced Diseases

Epsilon toxin (ETX), produced by type B and D strains of Clostridium perfringens, can cause fatal enterotoxaemia in ruminant animals, particularly sheep, cattle, and goats. Previous studies show that the cytotoxicity of ETX is dependent on the integrity of lipid rafts, the maintenance of which is ensured by cholesterol. Zaragozic acid (ZA) is a statin drug that reduces the synthesis of squalene, which is responsible for cholesterol synthesis. In this study, ZA significantly reduced the toxicity of ETX in Madin–Darby canine kidney (MDCK) cells. We show that ZA does not affect the binding of ETX to MDCK cells, but propidium iodide staining (PI) and Western blotting confirmed that ZA significantly disrupts the ability of ETX to form pores or oligomers in MDCK cells. Additionally, ZA decreased the phosphatidylserine exposure on the plasma membrane and increased the Ca2+ influx of the cells. Results of density gradient centrifugation suggest that ZA decreased the number of lipid rafts in MDCK membranes, which probably contributed to the attenuation of pore-formation. Moreover, ZA protected mice against ETX in vivo. All mice pre-treated with ZA for 48 h before exposure to an absolute lethal dose of ETX (6400 ng/kg) survived. In summary, these findings provide an innovative method to prevent ETX intoxication. Considering many pore-forming toxins require lipid rafts, we tested and found ZA also inhibited the toxicity of other toxins such as Clostridium perfringens Net B and β-toxin (CPB) and Staphylococcus aureus α-hemolysin (Hla). We expect ZA can thus be developed as a broad-spectrum medicine for the treatment of multiple toxins. In addition, other statins, such as lovastatin (LO), also reduced the toxicity of ETX. These findings indicate that statin medicines are potential candidates for preventing and treating multiple toxin-induced diseases.

Arsenic Trioxide Triggers Mitochondrial Dysfunction, Oxidative Stress, and Apoptosis via Nrf 2/Caspase 3 Signaling Pathway in Heart of Ducks

Arsenic is a common environmental pollutant and poses a serious threat to human and animal health. In this study, we used the ducks to mimic arsenic trioxide (ATO) exposure and investigated the mechanism of cardiac toxicity. The results indicated that ATO inhibited the body and organ growth of ducks, led to an increase in LDH content, and caused obvious deformity, ischemia infarction. It is found that ATO exacerbated the swell of mitochondrial and the contraction of cell nuclei in the heart of ducks through transmission electron microscopy (TEM). ATO also induced an increase in MDA content; inhibited the activation of the Nrf 2 pathway; downregulated the expression of mRNA and protein of Nrf 2, HO-1, and SOD-1; and upregulated the expression of mRNA and protein of Keap 1. At the same time, ATO induced apoptosis which not only upregulated the expression levels of mRNA and proteins (Caspase 3, Cyt-C, P53, Bax) but also decreased the mRNA and protein expression level of Bcl-2. These results indicated that ATO can lead to oxidative stress and apoptosis in the heart of ducks. In general, our research shows that ATO triggers mitochondrial dysfunction, oxidative stress, and apoptosis via Nrf 2/Caspase 3 signaling pathway in the heart of ducks.

Curcumin attenuates AFB1-induced duck liver injury by inhibiting oxidative stress and lysosomal damage

Aflatoxin B1 (AFB1), as the most toxic secondary metabolite produced by Aspergillus flavus, is a serious threat to human and animal health. Curcumin, a polyphenol from the plant turmeric, has demonstrated unique anti-damage properties in several studies. But, its ability to alleviate AFB1-induced liver damage in ducks and the underlying mechanisms are not completely elucidated. In this study, we investigated the intervention of curcumin on AFB1-induced hepatotoxicity in ducks. Research data showed that the combination of curcumin and AFB1 alleviated oxidative stress, reduced malondialdehyde (MDA) accumulation and relieved hepatotoxicity after 28 days of treatment, compared with AFB1. Also, curcumin upregulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream antioxidant enzymes (SOD, HO-1), which enhanced the antioxidant capacity of the liver. In addition, curcumin inhibited AFB1-induced lysosomal damage in the liver, with the character of reduced lysosomal membrane permeabilization, restored autophagic flux, and promoted lysosomal biogenesis, thereby enhancing the self-protective capacity of the liver. In conclusion, our results suggest that curcumin alleviates AFB1-induced duck hepatotoxicity by inhibiting oxidative stress and lysosomal damage.

Water-soluble Yb3+, Er3+ codoped NaYF4 nanoparticles induced SGC-7901 cell apoptosis through mitochondrial dysfunction and ROS-mediated ER stress

BACKGROUND

Nanoparticles are potential luminescent probes; among them, upconversion nanoparticles (UCNP) are currently being developed as fluorescent probes for biomedical applications. However, the molecular mechanisms of UCNP in human gastric cell lines remain poorly understood. Here, we aimed to examine UCNP cytotoxicity to SGC-7901 cells and explore its underlying mechanisms.

METHODS

The effects of 50-400 μg/mL UCNP on human gastric adenocarcinoma (SGC-7901) cells were investigated. Flow cytometry was used to evaluate reactive oxygen species (ROS), mitochondrial membrane potential (ΔΨm), intracellular Ca²⁺ levels, and apoptosis. Activated caspase-3 and nine activities were measured; meanwhile, cytochrome C (Cyt C) in the cytosol and B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein (Bax), protein kinase B (Akt), phosphorylated-Akt (p-Akt), 78 kDa glucose-regulated protein (GRP78), 94 kDa glucose-regulated protein (GRP94), calpain-1, and calpain-2 protein levels were also detected.

RESULTS

UCNP inhibited the viability of SGC-7901 cells in a concentration- and time-dependent manner and increased the proportion of cell apoptosis. Exposure to UCNP enhanced the ratio of Bax/Bcl-2, elevated the level of ROS, decreased ΔΨm, increased intracellular Ca²⁺ and Cyt C protein levels, decreased the levels of phosphorylated Akt, increased the activity of caspase-3 and caspase-9, and upregulated the protein expression of GRP-78, GRP-94, calpain-1 and calpain-2 in SGC-7901 cells.

CONCLUSION

UCNP induced SGC-7901 cell apoptosis by promoting mitochondrial dysfunction and ROS-mediated endoplasmic reticulum (ER) stress, initiating the caspase-9/caspase-3 cascade.

Associations of metal mixtures with metabolic-associated fatty liver disease and non-alcoholic fatty liver disease: NHANES 2003-2018

Objective

The hepatotoxicity of exposure to a single heavy metal has been examined in previous studies. However, there is limited evidence on the association between heavy metals mixture and non-alcoholic fatty liver disease (NAFLD) and metabolic-associated fatty liver disease (MAFLD). This study aims to investigate the associations of 13 urinary metals, individually and jointly, with NAFLD, MAFLD, and MAFLD components.

Methods

This study included 5,548 adults from the National Health and Nutrition Examination Survey (NHANES) 2003-2018. Binary logistic regression was used to explore the associations between individual metal exposures and MAFLD, NAFLD, and MAFLD components. Bayesian kernel machine regression (BKMR) and Quantile-based g-computation (QGC) were used to investigate the association of metal mixture exposure with these outcomes.

Results

In single metal analysis, increased levels of arsenic [OR 1.09 (95%CI 1.03-1.16)], dimethylarsinic acid [1.17 (95%CI 1.07-1.27)], barium [1.22 (95%CI 1.14-1.30)], cobalt [1.22 (95%CI 1.11-1.34)], cesium [1.35 (95%CI 1.18-1.54)], molybdenum [1.45 (95%CI 1.30-1.62)], antimony [1.18 (95%CI 1.08-1.29)], thallium [1.49 (95%CI 1.33-1.67)], and tungsten [1.23 (95%CI 1.15-1.32)] were significantly associated with MAFLD risk after adjusting for potential covariates. The results for NAFLD were similar to those for MAFLD, except for arsenic, which was insignificantly associated with NAFLD. In mixture analysis, the overall metal mixture was positively associated with MAFLD, NAFLD, and MAFLD components, including obesity/overweight, diabetes, and metabolic dysfunction. In both BKMR and QGC models, thallium, molybdenum, tungsten, and barium mainly contributed to the positive association with MAFLD.

Conclusion

Our study indicated that exposure to heavy metals, individually or cumulatively, was positively associated with NAFLD, MAFLD, and MAFLD components, including obesity/overweight, diabetes, and metabolic dysfunction. Additional research is needed to validate these findings in longitudinal settings.

Contemporary Comprehensive Review on Arsenic-Induced Male Reproductive Toxicity and Mechanisms of Phytonutrient Intervention

Arsenic (As) is a poisonous metalloid that is toxic to both humans and animals. Drinking water contamination has been linked to the development of cancer (skin, lung, urinary bladder, and liver), as well as other disorders such as diabetes and cardiovascular, gastrointestinal, neurological, and developmental damage. According to epidemiological studies, As contributes to male infertility, sexual dysfunction, poor sperm quality, and developmental consequences such as low birth weight, spontaneous abortion, and small for gestational age (SGA). Arsenic exposure negatively affected male reproductive systems by lowering testicular and accessory organ weights, and sperm counts, increasing sperm abnormalities and causing apoptotic cell death in Leydig and Sertoli cells, which resulted in decreased testosterone synthesis. Furthermore, during male reproductive toxicity, several molecular signalling pathways, such as apoptosis, inflammation, and autophagy are involved. Phytonutrient intervention in arsenic-induced male reproductive toxicity in various species has received a lot of attention over the years. The current review provides an in-depth summary of the available literature on arsenic-induced male toxicity, as well as therapeutic approaches and future directions.

Integrating transcriptome and physiological analysis to reveal the essential responses of Daphnia magna to antimony trioxide nanoparticle

Antimony (Sb) pollution has already posed a severe threat to the aquatic ecosystem. However, the toxicity mechanisms of Sb on aquatic organisms are far from being elucidated. One of the crucial questions remaining unresolved is the characterization of molecular toxicity of Sb(III). Transcriptomics profiling combined with physiological characterizations was applied to investigate the response of Daphnia magna to nano-size antimony trioxide (nATO) and its soluble Sb(III) counterpart antimony potassium tartrate (APT) in the present study. Both nATO and APT induced the formation of oxidative stress, enhanced the activities of anti-oxidative enzymes, altered the metabolism of xenobiotics, increased the concentration of hydrogen sulfide (H₂S) and nitric oxide (NO), and triggered the self-protection mechanisms such as ubiquitin-mediated proteolysis. In addition, nATO and APT caused damage to the nervous system of D. magna, inhibited its locomotion and nutrient uptake in a concentration-dependent manner. Moreover, nATO exposure enhanced the autophagy activity, reflected by the up-regulated expression of hypoxia-inducible factor-1α, calmodulin-dependent protein kinase-β, and inositol-requiring enzyme 1. The present study, for the first time, depicted a global map of cellular response to nATO, provided essential information on Sb(III) toxicity to aquatic organisms, and is of great significance to the development of Sb management strategies.

New insights into the interaction between duodenal toxicity and microbiota disorder under copper exposure in chicken: Involving in endoplasmic reticulum stress and mitochondrial toxicity

Copper (Cu) has been widely used in industrial agricultural production, but excess use can lead to toxic effect on host physiology, which poses a threaten to public hygiene. However, the relationship between gut microbiota and Cu-induced intestinal toxicity is unclear. Here, we identified that intestinal flora disturbance was related to duodenal toxicity under Cu exposure. We found that excess Cu disturbed gut microbiota homeostasis, resulting in Cu accumulation and intestinal damage. In addition, Cu considerably increased intestinal permeability by reducing expression of tight junction proteins (Claudlin-1, Occludin, and ZO-1). Meanwhile, Cu could induce endoplasmic reticulum stress, mitophagy, and mitochondria-mediated apoptosis in the duodenum, with the evidence by the elevated levels of GRP78, GRP94, LC3Ⅱ/LC3Ⅰ and Caspase-3 protein expression. Correlation analysis showed that Melainabacteria was closely related to tight junction proteins and endoplasmic reticulum stress of duodenum, indicating that disturbance of intestinal flora may aggravate the toxic effect of Cu. Therefore, our results suggest that the destruction of intestinal flora induced by excessive Cu may further lead to intestinal barrier damage, ultimately leading to endoplasmic reticulum stress, mitophagy and apoptosis. This research provides a new insight into interpretation of the interrelationship between microbiota disorder and duodenal toxicity under Cu exposure.

Zingiber officinale and Panax ginseng ameliorate ulcerative colitis in mice via modulating gut microbiota and its metabolites

Zingiber officinale and Panax ginseng, as well-known traditional Chinese medicines, have been used together to clinically treat ulcerative colitis with synergistic effects for thousands of years. However, their compatibility mechanism remains unclear. In this study, the shift of gut microbiome and fecal metabolic profiles were monitored by 16S rRNA sequencing technology and ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry analysis, respectively, which aimed to reveal the synergistic mechanism of Zingiber officinale and Panax ginseng on the amelioration of ulcerative colitis. The results showed that the relative abundance of beneficial bacteria (such as Muribaculaceae_norank, Lachnospiraceae NK4A136 group and Akkermansia) was significantly increased and the abundance of pathogenic bacteria (such as Bacteroides, Parabacteroides and Desulfovibrio) was markedly decreased after the intervention of Zingiber officinale-Panax ginseng herb pair. And a total of 16 differential metabolites related to ulcerative colitis were identified by the metabolomics analysis, which were majorly associated with the metabolic pathways, including arachidonic acid metabolism, tryptophan metabolism, and steroid biosynthesis. Based on these findings, it was suggested that the regulation of the gut microbiota-metabolite axis might be a potential target for the synergistic mechanism of Zingiber officinale-Panax ginseng herb pair in the treatment of ulcerative colitis. Furthermore, the integrated analysis of microbiome and metabolomics used in this study could also serve as a useful template for exploring the mechanism of other drugs.

Metabolomics as a valid analytical technique in environmental exposure research: application and progress

BACKGROUND

In recent years, studies have shown that exposure to environmental pollutants (e.g., radiation, heavy metal substances, air pollutants, organic pollutants) is a leading cause of human non-communicable diseases. The key to disease prevention is to clarify the harmful mechanisms and toxic effects of environmental pollutants on the body. Metabolomics is a high-sensitivity, high-throughput omics technology that can obtain detailed metabolite information of an organism. It is a crucial tool for gaining a comprehensive understanding of the pathway network regulation mechanism of the organism. Its application is widespread in many research fields such as environmental exposure assessment, medicine, systems biology, and biomarker discovery.

AIM OF REVIEW

Recent findings show that metabolomics can be used to obtain molecular snapshots of organisms after environmental exposure, to help understand the interaction between environmental exposure and organisms, and to identify potential biomarkers and biological mechanisms.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review focuses on the application of metabolomics to understand the biological effects of radiation, heavy metals, air pollution, and persistent organic pollutants exposure, and examines some potential biomarkers and toxicity mechanisms.

Histone demethylase JHDM2A participates in the repair of arsenic-induced DNA damage in L-02 cells by regulating DDB2

Arsenic is widely present in nature and is a class I carcinogen confirmed by the World Health Organization and the International Agency for Research on Cancer. The liver is responsible for biotransformation in the body and is one of the major organs where arsenic accumulates in the body, but the mechanisms of arsenic-induced abnormal DNA damage repair pathways in the liver are still unclear. Recent studies have revealed that epigenetic mechanisms play an important role in arsenic-induced lesions. In this study, an in vitro model was established using human normal hepatocytes L-02 to investigate the mechanism of the specific demethylase JHDM2A of H3K9me2 in the repair of arsenic-induced DNA damage in L-02 cells. The results showed that with the increase of arsenic concentrations, the extent of DNA damage in L-02 cells showed an increasing trend and total intracellular H3K9me2 expression was downregulated. In addition, the enrichment level of H3K9me2 in the promoter region of DBB2, a key factor of nucleotide repair (NBR), increased, while protein and mRNA expression levels showed a decreasing trend. Thereafter, we overexpressed and repressed JHDM2A and found a close association between JHDM2A and arsenic-induced DNA damage. DDB2 protein and mRNA expression was downregulated with JHDM2A overexpression and upregulated with JHDM2A repression, while DBB2 promoter region H3K9me2 enrichment levels remained at a high level, although they were affected after JHDM2A overexpression or knockdown to some extent. These results suggest a potential mechanism by which JHDM2A may regulate DDB2 gene expression, participate in the NBR process, and play a role in arsenic-induced DNA damage in L-02 cells, which is not the result of JHDM2A exerting demethylation on H3K9me2 in the DDB2 promoter region. Our results provided an epigenetic mechanism for endemic arsenicosis, as well as a scientific basis for potential prevention and control measures.

PINK1/Parkin-mediated mitophagy as a protective mechanism against AFB1-induced liver injury in mice

Aflatoxin B₁ (AFB₁) can cause oxidative stress leading to mitochondrial damage and subsequent liver injury. Although it is well-known that damaged mitochondria are eliminated by PINK1/Parkin-mediated mitophagy, this mechanism has not yet been characterized in the context of AFB₁-induced liver injury. In this study, male wild-type C57BL/6N mice were divided into groups 1-4, which were then orally administered 0, 0.5, 0.75, and 1 mg/kg body weight AFB₁ for 28 d, respectively. Our results demonstrated that oxidative stress, NLRP3-inflammasome activation, and mitochondrial damage were dose-dependently augmented in AFB₁-induced liver injury. Additionally, PINK1/Parkin-mediated mitophagy peaked in the groups that had received a mid-dose of AFB₁ (0.75 mg/kg), which was attenuated slightly in high-dose groups. Afterward, we further characterized AFB₁-induced liver injury by comparing wild-type C57BL/6N mice with Parkin knockout (Parkin^-/-) mice. We found that the restricted mitophagy in Parkin^-/- mice was associated with increased oxidative stress, NLRP3-inflammasome activation, mitochondrial damage, and liver injury. Taken together, these results indicate that PINK1/Parkin-mediated mitophagy plays an important role in attenuating AFB₁-induced liver injury in mice.

Relationships between urinary antimony concentrations and depressive symptoms in adults

BACKGROUND

Antimony is widely used in industrial production. The general population may be exposed to long-term low-dose antimony, and there are no studies on antimony and depression symptoms. This study aims to explore the relationships between urinary antimony concentrations and depressive symptoms in adults.

METHODS

We conducted a cross-sectional study using data from U.S. National Health and Nutrition Examination Survey (NHANES) 2007-2016 for urinary antimony (N = 8538). Depressive symptoms were assessed through Patient's Health Questionnaire (PHQ-9). In order to determine the relationships between urinary antimony concentrations and depressive symptoms, binary logistic regression model and restricted cubic spline were used. Dominance analysis was used to explore the relative importance between variables associated with depressive symptoms.

RESULTS

There was a significant positive relationship between urinary antimony concentrations and depressive symptoms in the general population, and OR with 95% CI was 1.72 (1.15, 2.60). This relationship also occurred in participants without disease status, and OR with 95% CI was 2.05 (1.10, 3.82). After stratified gender, the urinary antimony concentrations were positively correlated with depressive symptoms in the highest tertiles of female participants, and OR with 95% CI was 1.74 (1.06, 2.86). After adjusted urinary lead, arsenic, cadmium, and mercury as covariates, the result was still statistically significant, and OR with 95% CI was 1.83 (1.23, 2.72). Restricted cubic spline showed a nonlinear positive relationship between urinary antimony and depressive symptoms. Based on the result of dominance analysis, the relative importance of urinary antimony concentration accounted for 3.58%.

CONCLUSION

This study indicated that urinary antimony was positively related to depressive symptoms, especially in female.

The ZrO2 NPs enhanced the risk of arsenate by promoting its accumulation and reducing its detoxification during food chain transfer from Daphnia magna to zebrafish

Arsenic (As) can co-occur with zirconium dioxide nanoparticles (ZrO₂ NPs) in aquatic environments, but their combined influence along the aquatic food chain is barely explored. This study constructed water flea Daphnia magna - zebrafish Danio rerio to evaluate the impact of ZrO₂ NPs on the accumulation, trophic transfer, transformation, and detoxification of arsenate (As(V)). The zebrafish were fed D. magna exposed to As(V), ZrO₂ NPs, or As(V) + ZrO₂ NPs for 20 d. Results demonstrated that ZrO₂ NPs significantly facilitated total As and As(V) sorption in D. magna and in tissues of zebrafish. ZrO₂ NPs enhanced the transformation of inorganic arsenic (iAs) to monomethylated acid (MMA), while decreased synthesis of arsenobetaine (AsB) in tissues, leading to iAs increased. Co-exposed As(V) and ZrO₂ NPs facilitated upregulation of absorption-related genes (aqp7) and As biotransformation-related genes (gst, gss), and detoxification and oxidative stress-related genes (mt2, cat, sod1 and sod2). Therefore, genetic expression coupling with biotransformation for the first time demonstrated that As(V) combined with ZrO₂ NPs led to increased harm to D. magna and zebrafish and amplified the ecological risks of As(V) along the aquatic food chain. Attention should be paid to the combined toxicity of As(V) and ZrO₂ NPs in aquatic environment.

Curcumin activates the Nrf2 Pathway to alleviate AFB1-induced immunosuppression in the spleen of ducklings

Ducklings is one of the most susceptible poultry to Aflatoxin B1 (AFB1) which widely existed in duckling products will also in turn affect human health. Curcumin (CUR) has significant effects on immune regulation and anti-oxidation. But whether CUR alleviates toxic effects on duckling spleen induced by AFB1 remains largely unknown. In this study we treated duckings with AFB1 and CUR for 21 days before harvesting serum and spleen tissue for analyses. The results showed that AFB1 damaged the spleen tissue of ducklings by activating the NF-κB signaling pathway. And the addition of CUR not only promoted the growth of ducklings, but also enhanced the immune function of the spleen and reduced the damage of AFB1 to the spleen tissue. At the same time, CUR activated the Nrf2 signaling pathway, upregulated the expression of related antioxidant enzymes, inhibited the NF-kB signaling pathway, and ultimately reducing the inflammation of the duckling spleen induced by AFB1. It has been suggested from these results that Nrf2 pathway might be a potential therapeutic target for CUR to treat AFB1-induced immunosuppression in ducklings.

Arsenic causes mitochondrial biogenesis obstacles by inhibiting the AMPK/PGC-1α signaling pathway and also induces apoptosis and dysregulated mitophagy in the duck liver

Arsenic is a dangerous metalloid-material which is known to cause liver injury in many animals and humans. However, little is known about the underlying mechanism of arsenic-induced hepatotoxicity in poultry. This study was executed to systematically investigate the potential role of mitochondrial biogenesis, mitophagy and apoptosis in duck hepatotoxicity caused by arsenic. Results showed that the body weight and liver coefficient of duck had distinct changed after arsenic-exposure, and the arsenic content in serum and liver also increased significantly in a dose-dependent manner. Meanwhile, histopathological examination and metabolomics results showed that arsenic-exposure caused severe steatosis and metabolism disorder in liver tissues. Furthermore, arsenic-exposure significantly inhibited AMPK/PGC-1α-mediated mitochondrial biogenesis, determined by the ultrastructure observation and down-regulation of p-AMPKα/AMPKα, PGC-1α, NRF1, NRF2, TFAM, TFB1M, TFB2M and COX-Ⅳ expression levels. Besides, arsenic-treatment obviously increased the levels of mitophagy (PINK1, Parkin, LC3, P62) and pro-apoptotic (Caspase-3, Caspase-9, Cleaved Caspase-3, Cytc, Bax, P53) indexes, and simultaneously resulted in reductions in anti-apoptosis index (Bcl-2). Overall, our findings provided evidences that arsenic-induced duck hepatotoxicity may be caused by a combination of impaired mitochondrial biosynthesis, mitophagy, and mitochondrial-dependent apoptosis. To our knowledge, this is the first report to systematically investigate the potential mechanism of arsenic-induced hepatotoxicity in poultry.

Curcumin alleviates arsenic-induced injury in duck skeletal muscle via regulating the PINK1/Parkin pathway and protecting mitochondrial function

Arsenic is a well-known environmental pollutant due to its toxicity, which can do harm to animals and human. Curcumin is a polyphenolic compound derived from turmeric, commonly accepted to have antioxidant properties. However, whether curcumin can ameliorate the damage caused by arsenic trioxide (ATO) in duck skeletal muscle remains largely unknown. Therefore, the present study aims to investigate the potential molecular mechanism of curcumin against ATO-induced skeletal muscle injury. The results showed that treating with curcumin could attenuate body weight loss induced by ATO and reduced arsenic content accumulation in the skeletal muscle of duck. Curcumin was also able to alleviated the oxidative stress triggered by ATO, which was manifested by the increase of T-AOC and SOD, and MDA decrease. Moreover, we observed that curcumin could ease mitochondrial damage and vacuolate degeneration of nucleus. Our further investigation found that ATO disrupted normal mitochondrial fission/fusion (Drp1, OPA1, Mfn1/2) and restrained mitochondrial biogenesis (PGC-1α, Nrf1/2, TFAM), while curcumin could promote mitochondrial fusion and activated PGC-1α pathway. Furthermore, curcumin was found that it could not only reduce the mRNA and protein levels of mitophagy (PINK1, Parkin, LC3, p62) and pro-apoptotic genes (p53, Bax, Caspase-3, Cytc), but also increased the levels of anti-apoptotic genes (Bcl-2). In conclusion, curcumin was able to alleviate ATO-induced skeletal muscle damage by improving mitophagy and preserving mitochondrial function, which can serve as a novel strategy to take precautions against ATO toxicity.

The role of Fas-FasL-FADD signaling pathway in arsenic-mediated neuronal apoptosis in vivo and in vitro

The molecular mechanisms underlying arsenic-induced neurotoxicity have not been completely elucidated. Our study aimed to determine the role of the Fas-FasL-FADD signaling pathway in arsenic-mediated neuronal apoptosis. Pathological and molecular biological tests were performed on the cerebral cortex of arsenic-exposed rats and SH-SY5Y neuroblastoma cells. Arsenic induced apoptosis in the cortical neurons, which corresponded to abnormal ultrastructural changes. Mechanistically, arsenic activated the Fas-FasL-FADD signaling pathway and the downstream caspases both in vivo and in vitro. ZB4 treatment reversed the apoptotic effects of arsenic on the SHSY5Y cells. Taken together, arsenic induces neurotoxicity by activating the Fas-FasL-FADD signaling pathway.

Dual role of cadmium in rat liver: Inducing liver injury and inhibiting the progression of early liver cancer

The heavy metal cadmium (Cd) can induce damage in liver and liver cancer cells; however, the mechanism underlying its toxicity needs to be further verified in vivo. We daily administered CdCl₂ to adult male rats at different dosages via gavage for 12 weeks and established rat liver injury model and liver cancer model to study the dual role of Cd in rat liver. Increased exposure to Cd resulted in abnormal liver function indicators, pathological degeneration, rat liver cell necrosis, and proliferation of collagen fibres. Using immunohistochemistry, we found that the area of GST-P-positive precancerous liver lesions decreased in a dose-dependent manner. Real-time quantitative polymerase chain reaction, western blot, immunohistochemistry, and transmission electron microscopy revealed that Cd induced mitophagy, as well as mitophagy blockade, as evidenced by the downregulation of TOMM20 and upregulation of LC3II and P62 with increasing Cd dose. Next, the expression of PINK1/Parkin, a classic signalling pathway protein that regulates mitophagy, was examined. Cd was found to promote PINK1/Parkin expression, which was proportional to the Cd dose. In conclusion, Cd activates PINK1/Parkin-mediated mitophagy in a dose-dependent manner. Mitophagy blockade likely aggravates Cd toxicity, leading to the dual role of inducing liver injury and inhibiting the progression of early liver cancer.

Arsenic exposure induces intestinal barrier damage and consequent activation of gut-liver axis leading to inflammation and pyroptosis of liver in ducks

Arsenic is an important hazardous metalloid commonly found in polluted soil, rivers and groundwater. However, few studies exist regarding the effect of arsenic trioxide (ATO) on the gut-liver axis and consequent hepatotoxicity in waterfowl. Here, we investigated the influence of ATO on duck intestines and livers, and explored the role of the gut-liver axis in ATO-induced hepatotoxicity and intestinal toxicity. Our results demonstrated that ATO-exposure induced intestinal damage, liver inflammatory cell infiltration and vesicle steatosis. Additionally, the intestinal microbiota community in ATO-exposed ducks displayed significantly decreased α-diversity and an altered bacterial composition. Moreover, ATO-exposure markedly reduced the expression of intestinal barrier-related proteins (Claudin-1, MUC2, ZO-1 and Occludin), resulting in increased intestinal permeability and elevated lipopolysaccharide levels. Simultaneously, ATO-exposure also upregulated pyroptosis-related index levels in the liver and jejunum, and increased pro-inflammatory cytokine production (IFN-γ, TNF-α, IL-18, and IL-1β). Our further mechanistic studies showed that ATO-induced liver and jejunum inflammation were provoked by the activation of the LPS/TLR4/NF-κB signaling pathway and NLRP3 inflammasome. In summary, these results manifested that ATO exposure can cause liver and jejunal inflammation and pyroptosis, and the indirect gut-liver axis pathway may play an essential role in the potential mechanism of ATO-induced hepatotoxicity.

Arsenic (III) and/or Antimony (III) induced disruption of calcium homeostasis and endoplasmic reticulum stress resulting in apoptosis in mice heart

Arsenic (As) and antimony (Sb) are known as an environmental contaminant with cardiotoxicity properties. The endoplasmic reticulum (ER) is the largest calcium reservoir in the cell, and its calcium homeostasis disorder plays a vital role in endoplasmic reticulum stress (ERS) and apoptosis. The objective of this study was to investigate whether As and Sb induced apoptosis via endoplasmic reticulum stress (ERS) linked to calcium homeostasis disturbance. In this study, thirty-two adult mice were gavage-fed daily with As₂O₃ (4 mg/kg), SbCl₃ (15 mg/kg) and co-treat with SbCl₃ (15 mg/kg) and As₂O₃ (4 mg/kg) daily for 60 days. It was observed that As or/and Sb caused histopathological lesions and ER expansion of the heart. Meanwhile, the gene expression of ER Ca²⁺ release channels (RyR2 and IP3R) and calmodulin-dependent protein kinase II (CaMKII) increased while the levels of mRNA and protein of ER Ca²⁺ uptake channel (SERCA2) downregulated significantly compared to the controls. Then, As or/and Sb induced ERS and triggered the ER apoptotic pathway by activating unfolded protein response (UPR)-associated genes ((PERK, ATF6, IRE1, XBP1, JNK, GRP78), and apoptosis-related genes (Caspase12, Caspase3, p53, CHOP). Above indicators in As + Sb group became more severe than that of As group and Sb group. Overall, our results proved that the cardiotoxicity caused by As or/and Sb might be concerning disturbing calcium homeostasis, which induced apoptosis through the ERS pathway.