Toxic effects of arsenic trioxide on spermatogonia are associated with oxidative stress, mitochondrial dysfunction, autophagy and metabolomic alterations

Could the Effect of Arsenic on the Testis be Reversed after Removing the Insult? A Meta-analysis Study

Arsenic in drinking water has been associated with an increased risk of health concerns. This metalloid is ingested and distributed throughout the body, accumulating in several organs, including the testis. In this organ, arsenic disturbs steroidogenesis and spermatogenesis and affects male fertility. Although testicular impairment induced by arsenic is well documented, it is still controversial whether such disturbance remains days after the removal of arsenic insult. Therefore, we used a meta-analytical approach to evaluate the magnitude of arsenic effects on testicular parameters and verify whether a withdrawal period can mitigate these alterations. The search terms 'testis" and 'arsenic' were used in PubMed/Medline, Scopus, and Web of Science databases. A total of 1,217 articles were obtained from the literature search, and 73 articles were included in this meta-analysis. Our results showed that arsenic negatively affected hormone synthesis and secretion, testicular weight, tubular and intertubular morphometry, and daily sperm production 24 h after ending exposure. Arsenic inhibited antioxidant enzyme activity, culminating in high oxidative metabolite production and apoptosis occurrence. Most of these effects were not observed in the testis between eight and fifty days after arsenic withdrawal, remaining endocrine dysregulation and oxidative metabolite production. Sodium arsenite was the most toxic compound to the testis at subchronic exposure. These findings shed light on the plasticity and regenerative capacity of testicular interstitium and spermatogonial stem cell niche. However, sexual hormone imbalance remained after arsenic removal. This review evidenced the importance of understanding its toxicity's short- and long-term effects on male reproductive competence.

Mitochondrial Dysfunction in Environmental Toxicology: Mechanisms, Impacts, and Health Implications

Mitochondria, pivotal to cellular metabolism, serve as the primary sources of biological energy and are key regulators of intracellular calcium ion storage, crucial for maintaining cellular calcium homeostasis. Dysfunction in these organelles impairs ATP synthesis, diminishing cellular functionality. Emerging evidence implicates mitochondrial dysfunction in the etiology and progression of diverse diseases. Environmental factors that induce mitochondrial dysregulation raise significant public health concerns, necessitating a nuanced comprehension and classification of mitochondrial-related hazards. This review systematically adopts a toxicological perspective to illuminate the biological functions of mitochondria, offering a comprehensive exploration of how toxicants instigate mitochondrial dysfunction. It delves into the disruption of energy metabolism, the initiation of mitochondrial fragility and autophagy, and the induction of mutations in mitochondrial DNA by mutagens. The overarching objective is to enhance our understanding of the repercussions of mitochondrial damage on human health.

Integrating Transcriptome and Metabolome Analyses Revealed Salinity Induces Arsenobetaine Biosynthesis in Marine Medaka (Oryzias melastigma)

Marine fish exhibit elevated levels of arsenobetaine (AsB), while the impact and underlying mechanism of salinity on AsB biosynthesis remain inadequately explored. In this study, marine medaka (Oryzias melastigma), typically inhabiting 30‰ high salinity, were gradually acclimated to low salinities of 20, 10, and 0‰. Following acclimation, the fish were exposed to arsenate (As(V)) in their diet for 30 days. Results showed a significant accumulation of total arsenic (As) and AsB concentrations in the muscle and head tissues of the exposed fish, with these accumulations exhibiting a positive correlation with water salinity. Transcriptome analyses revealed that exposure to As(V) at low salinity may disrupt membrane components and induce cytoskeletal injuries, while at high salinity, it triggered oxidoreductase activity and transmembrane transport. Metabolome analyses indicated that low salinity induced osmotic stress, resulting in an increased requirement for amino acids to upload intracellular osmotic equilibrium in O. melastigma. Furthermore, the key organic osmolytes and amino acids, including taurine, l-methionine, guanidinoethyl sulfonate, and N-acetyl-l-aspartic acid, exhibited a negative correlation with the AsB concentration. These findings indicated that salinity can regulate osmotic balance by influencing amino acid synthesis under low salinity and stimulating AsB synthesis under high salinity conditions in O. melastigma. This study provides insights into the impact of high salinity on AsB biosynthesis, the underlying regulatory mechanisms, and implications for managing As(V) risk.

Long-term arsenic exposure decreases mice body weight and liver lipid droplets

Arsenic (As) is a widespread global pollutant, and there is significant controversy surrounding its complex relationship with obesity, primarily focused on short-term exposure. Recognizing the prolonged nature of dietary arsenic exposure, this study involved feeding mice with arsenic-contained food for 14 months. The results showed that mice exposed to arsenic developed a non-alcoholic fatty liver condition, characterized by a light-yellow hue on the liver surface and various pathological alterations in the liver cells, including enlarged nuclei, cellular necrosis, inflammatory infiltration, dysfunctional mitochondria, and endoplasmic reticulum disorganization. There were also disruptions in biochemistry indices, with a significant increase in total cholesterol (TC) level and a decrease in high-density lipoprotein (HDL) level. However, some contradictory observations occurred, such as a significant decrease in body weight, triglyceride (TG) level, and the numbers of lipid droplets. Several genes related to lipid metabolism were tested, and a model was used to explain these discrepancies. Besides, examinations of the colon revealed compromised intestinal barrier function and signs of inflammation. Fecal 16S rRNA sequencing and pseudo-targeted metabolomics revealed disruptions in internal homeostasis, such as modules, nodes, connections, and lipid-related KEGG pathways. Fecal targeted metabolomics analyses of short-chain fatty acids (SCFAs) and bile acids (BAs) demonstrated a significant upregulation in three primary bile acids (CA, CDCA, TCDCA), four secondary bile acids (TUDCA, DCA, LCA, GUDCA), and total SCFAs level. Oxidative stress and inflammation were also evident. Additionally, based on correlation analysis and mediation analysis, it was assumed that changes in the microbiota (e.g., Dubosiella) can impact the liver metabolites (e.g., TGs) through alterations in fecal metabolites (e.g., LPCs). These findings provide a theoretical reference for the long-term effect of arsenic exposure on liver lipid metabolism.

Rosolic acid as a novel activator of the Nrf2/ARE pathway in arsenic-induced male reproductive toxicity: An in silico study

Male reproductive toxicity as a result of arsenic exposure is linked with oxidative stress and excessive generation of reactive oxygen species (ROS). It leads to an imbalance between ROS production and antioxidant defense mechanisms ultimately resulting in male infertility. The nuclear factor erythroid 2 (NFE2)-related factor 2 (Nrf2) is a transcription factor that responds to cellular stressors controlling the oxidative state, mitochondrial dysfunction, inflammation, and proteostasis. This study aims to investigate the potential of Rosolic acid (ROA) to act as a novel Nrf2 activator by mitigating oxidative stress to combat arsenic-induced male reproductive toxicity. The protein and ligands were prepared in the BIOVIA Discovery Studio, followed by protein-ligand docking using auto dock vina integrated with the PyRx-Virtual Screening Tool. Then the ADME properties were analyzed using the SwissADME tool to get a clear idea about the physicochemical properties, lipophilicity, water solubility, pharmacokinetics, and drug likeliness of ROA. It was followed by molecular dynamics simulation (MDS) studies using GROMACS. The 3D and 2D interaction maps revealed the interactions of Keap 1 with ROA. Keap1-ROA complex was found to have a binding energy of -7.8 kcal/mol. ROA showed 0 violations for Lipinski and 0 alerts each for PAINS and Brenk and a bioavailability score of 0.55. The BOILED-Egg representation showcases that ROA is predicted as passively crossing the blood-brain barrier (BBB). The MDS described 2FLU-ROA as a stable system. This work portrays that ROA can be a potent Nrf2 activator by exhibiting an inhibitory activity against the Keap1 protein and thus mitigating oxidative stress in arsenic-induced male reproductive toxicity.

Crosstalk among Reactive Oxygen Species, Autophagy and Metabolism in Myocardial Ischemia and Reperfusion Stages

Myocardial ischemia is the most common cardiovascular disease. Reperfusion, an important myocardial ischemia tool, causes unexpected and irreversible damage to cardiomyocytes, resulting in myocardial ischemia/reperfusion (MI/R) injury. Upon stress, especially oxidative stress induced by reactive oxygen species (ROS), autophagy, which degrades the intracellular energy storage to produce metabolites that are recycled into metabolic pathways to buffer metabolic stress, is initiated during myocardial ischemia and MI/R injury. Excellent cardioprotective effects of autophagy regulators against MI and MI/R have been reported. Reversing disordered cardiac metabolism induced by ROS also exhibits cardioprotective action in patients with myocardial ischemia. Herein, we review current knowledge on the crosstalk between ROS, cardiac autophagy, and metabolism in myocardial ischemia and MI/R. Finally, we discuss the possible regulators of autophagy and metabolism that can be exploited to harness the therapeutic potential of cardiac metabolism and autophagy in the diagnosis and treatment of myocardial ischemia and MI/R.

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.

Arsenic exposure caused male infertility indicated by testis and sperm metabolic dysfunction in SD rats

Arsenic containment is one of the most severe environmental problems. It has been reported that arsenic exposure could cause male reproductive damage. However, the evidence chain from sodium arsenite (NaAsO2) exposure to adverse male fertility outcomes has not been completed by molecular events. In this study, adult male rats were exposed to NaAsO2 for eight weeks via drinking water for verifying their reproductive capacity by checking the phenotypes of testis damage, sperm quality, and female pregnancy rate. H&E staining indicated testicular cells had atrophied, and necrosis was observed under transmission electron microscopy. Sperm viability tended to decrease, and sperm malformation increased. Notably, metabolites in the testes and sperm showed substantial disruption, especially sperm metabolites. The pregnancy rate tests showed that arsenic decreased male rats' reproduction, with some adverse outcomes of the increased numbers of unpregnant females. However, the fetal crown-rump length remained unaltered, indicating that the pregnancy rate was impacted by arsenic exposure but not fetal growth. On arsenic toxicometabolomics analysis, docosahexaenoic acid (DHA) in sperm was the clearest metabolic sign to correlate with the unpregnant rate. In summary, arsenic exposure can cause male infertility via the injured sperm, which results in decreased female pregnancy. The DHA information may imply the dietary intervention for improving sperm quality. Although the fetal growth of the successful pregnancy has not been affected, the changes in epigenetic phenotypes carried by sperms still need to be verified.

The constructive and destructive impact of autophagy on both genders' reproducibility, a comprehensive review

Reproduction is characterized by a series of massive renovations at molecular, cellular, and tissue levels. Recent studies have strongly tended to reveal the involvement of basic molecular pathways such as autophagy, a highly conserved eukaryotic cellular recycling, during reproductive processes. This review comprehensively describes the current knowledge, updated to September 2022, of autophagy contribution during reproductive processes in males including spermatogenesis, sperm motility and viability, and male sex hormones and females including germ cells and oocytes viability, ovulation, implantation, fertilization, and female sex hormones. Furthermore, the consequences of disruption in autophagic flux on the reproductive disorders including oligospermia, azoospermia, asthenozoospermia, teratozoospermia, globozoospermia, premature ovarian insufficiency, polycystic ovarian syndrome, endometriosis, and other disorders related to infertility are discussed as well.Abbreviations: AKT/protein kinase B: AKT serine/threonine kinase; AMPK: AMP-activated protein kinase; ATG: autophagy related; E2: estrogen; EDs: endocrine disruptors; ER: endoplasmic reticulum; FSH: follicle stimulating hormone; FOX: forkhead box; GCs: granulosa cells; HIF: hypoxia inducible factor; IVF: in vitro fertilization; IVM: in vitro maturation; LCs: Leydig cells; LDs: lipid droplets; LH: luteinizing hormone; LRWD1: leucine rich repeats and WD repeat domain containing 1; MAP1LC3: microtubule associated protein 1 light chain 3; MAPK: mitogen-activated protein kinase; MTOR: mechanistic target of rapamycin kinase; NFKB/NF-kB: nuclear factor kappa B; P4: progesterone; PCOS: polycystic ovarian syndrome; PDLIM1: PDZ and LIM domain 1; PI3K: phosphoinositide 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; PtdIns3K: class III phosphatidylinositol 3-kinase; POI: premature ovarian insufficiency; ROS: reactive oxygen species; SCs: Sertoli cells; SQSTM1/p62: sequestosome 1; TSGA10: testis specific 10; TST: testosterone; VCP: vasolin containing protein.

The Protective Effects of Trametes Versicolor on Arsenic-Induced Male Reproductive Toxicity through Regulation of Oxidative Stress: A Biochemical and Histopathological Survey

Exposure to arsenic is linked to a wide range of diseases, in particular male reproductive toxicities. Trametes versicolor is a traditional medicinal fungus with a remarkable potential for antioxidant activity. The purpose of this study was to examine the ameliorating effects of water and methanol extracts of T. versicolor on arsenic-induced male reproductive toxicities via the abrogation of oxidative stress. The mice were divided as follows: control: normal saline, As: arsenic (15 mg/kg), WE: water extract (400 mg/kg), ME: methanol extract (400 mg/kg), As + WE: arsenic (15 mg/kg) + water extract (100, 200, 400 mg/kg), As + ME: arsenic (15 mg/kg) + methanol extract (100, 200, 400 mg/kg), and positive control: arsenic (15 mg/kg) + vitamin C (500 mg/kg). Animals were treated via the intraperitoneal route. About 24 hr later, the mice were euthanized, and oxidative stress parameters (reactive oxygen species [ROS], lipid peroxidation, glutathione concentration, protein carbonylation, glutathione peroxidase, and superoxide dismutase activity), histopathological changes and sperm parameters (count, motility, and morphology) were examined in the testicular tissue. Arsenic caused significant pathological changes in the testicular tissue and sperm morphology and significantly reduced sperm count and motility. Moreover, arsenic mediated oxidative stress via significant increases in ROS generation, lipid peroxidation, and protein carbonyl content, as well as significant depletion in glutathione concentration and superoxide dismutase and glutathione peroxidase activities. Although, coadministration of water and methanol extracts of T. versicolor at 200 and 400 mg/kg counteracted arsenic-induced oxidative and histopathological damages and improved sperm parameters. Our study indicated that T. versicolor ameliorated arsenic-induced testis toxicity and sperm dysfunction via attenuation of oxidative damage.

Constructing a seventeen-gene signature model for non-obstructive azoospermia based on integrated transcriptome analyses and WGCNA

BACKGROUND

Non-obstructive azoospermia (NOA) affects approximately 1% of the male population worldwide. The underlying mechanism and gene transcription remain unclear. This study aims to explore the potential pathogenesis for the detection and management of NOA.

METHODS

Based on four microarray datasets from the Gene Expression Omnibus database, integrated analysis and weighted correlation network analysis (WGCNA) were used to obtain the intersected common differentially expressed genes (DESs). Differential signaling pathways were identified via GO and GSVA-KEGG analyses. We constructed a seventeen-gene signature model using least absolute shrinkage and selection operation (LASSO) regression, and validated its efficacy in another two GEO datasets. Three patients with NOA and three patients with obstructive azoospermia were recruited. The mRNA levels of seven key genes were measured in testicular samples, and the gene expression profile was evaluated in the Human Protein Atlas (HPA) database.

RESULTS

In total, 388 upregulated and 795 downregulated common DEGs were identified between the NOA and control groups. ATPase activity, tubulin binding, microtubule binding, and metabolism- and immune-associated signaling pathways were significantly enriched. A seventeen-gene signature predictive model was constructed, and receiver operating characteristic (ROC) analysis showed that the area under the curve (AUC) values were 1.000 (training group), 0.901 (testing group), and 0.940 (validation set). The AUCs of seven key genes (REC8, CPS1, DHX57, RRS1, GSTA4, SI, and COX7B) were all > 0.8 in both the testing group and the validation set. The qRT-PCR results showed that consistent with the sequencing data, the mRNA levels of RRS1, GSTA4, and COX7B were upregulated, while CPS1, DHX57, and SI were downregulated in NOA. Four genes (CPS1, DHX57, RRS1, and SI) showed significant differences. Expression data from the HPA database showed the localization characteristics and trajectories of seven key genes in spermatogenic cells, Sertoli cells, and Leydig cells.

CONCLUSIONS

Our findings suggest a novel seventeen-gene signature model with a favorable predictive power, and identify seven key genes with potential as NOA-associated marker genes. Our study provides a new perspective for exploring the underlying pathological mechanism in male infertility.

The interplay of arsenic, silymarin, and NF-ĸB pathway in male reproductive toxicity: A review

Arsenic toxicity is one of the most trending reasons for several malfunctions, particularly reproductive toxicity. The exact mechanism of arsenic poisoning is a big question mark. Exposure to arsenic reduces sperm count, impairs fertilization, and causes inflammation and genotoxicity through interfering with autophagy, epigenetics, ROS generation, downregulation of essential protein expression, metabolite changes, and hampering several signaling cascades, particularly by the alteration of NF-ĸB pathway. This work tries to give a clear idea about the different aspects of arsenic resulting in male reproductive complications, often leading to infertility. The first part of this article explains the implications of arsenic poisoning and the crosstalk of the NF-ĸB pathway in male reproductive toxicity. Silymarin is a bioactive compound that exerts anti-cancer and anti-inflammatory properties and has demonstrated hopeful outcomes in several cancers, including colon cancer, breast cancer, and skin cancer, by downregulating the hyperactive NF-ĸB pathway. The next half of this article thus sheds light on silymarin's therapeutic potential in inhibiting the NF-ĸB signaling cascade, thus offering protection against arsenic-induced male reproductive toxicity.

SIRT1/PGC-1α is involved in arsenic-induced male reproductive damage through mitochondrial dysfunction, which is blocked by the antioxidative effect of zinc

Exposure to arsenic poses threats to male reproductive system, including impairing the testes and sperm quality. Although an association regarding arsenic exposure and male reproductive damage has been reported, the undergoing molecular mechanisms and interventions for prevention remain unclear. For the present work, male mice were exposed to 0, 2.5, 5, or 10 ppm sodium arsenite (NaAsO₂) for 8 months. The results showed that arsenic-exposed mice had reduced fertility with abnormalities in the testes, epididymides, and sperm. Exposure of mice to arsenic caused a redox imbalance, decreased SIRT1 and PGC-1α levels, and affected mitochondrial biogenesis and proteins related to mitochondrial dynamics. For immortalized spermatogenic (GC-2) cells, arsenic caused apoptosis and oxidative stress, reduced SIRT1/PGC-1α levels and ATP production, inhibited mitochondrial respiration, and changed the mitochondrial membrane potential (MMP). Mitochondrial biogenesis and dynamics were also impaired. However, by reducing mitochondrial damage in GC-2 cells, upregulation of SIRT1 or zinc (Zn) supplementation reversed the apoptosis induced by arsenic. For mice, Zn supplementation blocked arsenic-induced oxidative stress, the decreases of SIRT1 and PGC-1α levels, and the impairment of mitochondrial function, and it reversed the damage to testes, low sperm quality, and low litter size. Collectively, these results suggest that arsenic causes excessive production of ROS, inhibits the SIRT1/PGC-1α pathway, and causing mitochondrial dysfunction by mediating impairment of mitochondrial biogenesis and dynamics, which results in germ cells apoptosis and male reproductive damage, processes that are blocked by Zn via an antioxidative effect. Our study contributes to understanding of the mechanisms for arsenic-induced male reproductive damage and points to the therapeutic significance of Zn.

Long-term Copper Exposure Induces Mitochondrial Dynamics Disorder and Mitophagy in the Cerebrum of Pigs

Copper (Cu) is an essential trace element for growth and development in most organisms. However, environmental exposure to high doses of Cu can damage multiple organs. To investigate the underlying mechanism of Cu toxicity on mitochondrial dynamics and mitophagy in the cerebrum of pigs, 60 30-day-old pigs were randomly divided into three groups and treated with different contents of anhydrous Cu sulfate in the diets (Cu 10 mg/kg, control group; Cu 125 mg/kg, group I; Cu 250 mg/kg, group II) for 80 days. The Cu levels and histological changes in the cerebrum were measured. Moreover, the protein and mRNA expression levels related to mitophagy and mitochondrial dynamics were determined. The results showed that the contents of Cu were increased in the cerebrum with increasing dietary Cu. Vacuolar degeneration was found in group I and group II compared to the control group. Additionally, the protein and mRNA expression levels of PINK1, Parkin, and Drp1 and the protein level of LC3-II were remarkably upregulated with increasing levels of dietary Cu. Nevertheless, the protein and mRNA expression levels of MFN1 and MFN2 and the mRNA expression of P62 were obviously downregulated in a Cu dose-dependent manner. Overall, these results suggested that excess Cu could trigger mitochondrial dynamics disorder and mitophagy in the pig cerebrum, which provided a novel insight into Cu-induced toxicology.

Arsenic exposure and its implications in male fertility

Arsenic exposure is a global health concern. This toxic metalloid is ubiquitous in the environment and contaminates food and drinking water. Once ingested, it undergoes a complex metabolic process within the body, which contributes to its accumulation and reactivity. Arsenic toxicity stems from the induction of oxidative stress, inhibition of thiol-containing proteins, and mimicry of inorganic phosphates. Arsenic poisoning is associated with the development of reproductive disorders. In males, arsenic causes a reduction in testicular weight and alterations in steroidogenesis and spermatogenesis. Moreover, it reduces the number and quality of spermatozoa harvested from the cauda epididymis. The mitochondria are targets of arsenic toxicity because of the production of free radicals and their high content of cysteine-rich proteins and fatty acids. Mitochondrial dysfunction may contribute to reproductive disorders because this organelle is crucial for controlling testicular and epididymal events related to sperm production and maturation. All of these alterations mediated by arsenic exposure contribute to the failure of male reproductive competence by reducing gamete viability. This review describes the potential mechanisms of arsenic toxicity, its detrimental effects on male reproductive organs, and consequences on sperm fertility.

The effect of isovitexin on lipopolysaccharide-induced renal injury and inflammation by induction of protective autophagy

Chronic kidney disease (CKD) is a systemic inflammatory syndrome that includes tubulointerstitial inflammation. Lipopolysaccharide (LPS), the outer membrane of Gram-negative bacteria, can increase reactive oxygen species production (ROS) that triggers cell inflammation. Isovitexin (IV) is a flavone that has the potential for anticancer, antioxidant, and anti-inflammatory. This study aimed to hypothesize that IV inhibited LPS-induced renal injury in vitro and in vivo. In vitro study, IV prevented LPS-induced ROS production and increased cell viability on SV40-MES-13 cells. Additionally, IV ameliorated mitochondrial membrane potential, downregulated inflammation and pyroptosis factors on LPS treatment. We found that LPS treatment reduced the expression of autophagy, however, this effect was reversed by IV. In vivo study, the renal injury model in C57BL/6 mice cotreatment with IV was examined. In addition, IV decreased LPS-induced glomerular atrophy and reduced inflammation-related cytokines releases. Further showed that IV could significantly reduce LPS-induced inflammation and pyroptosis factors in mice. Under the immunostaining, increased fluorescence of LC3 autophagy-related protein was recovered by IV. In summary, IV ameliorated renal injury, inflammation and increased protected autophagy by anti-ROS production, anti-inflammation, and anti-pyroptosis. In the future, the safety of isovitexin as a novel perspective for CKD patients should be evaluated in further clinical studies.

Analyzing toxicological effects of AsIII and AsV to Chlamys farreri by integrating transcriptomic and metabolomic approaches

Inorganic arsenic (iAs) is a widespread contaminant in marine environments, which is present in two different oxidation states (arsenate (AsV) and arsenite (AsIII)) that have complex toxic effects on marine organisms. The scallop Chlamys farreri (C. farreri) accumulates high levels of As and is a suitable bioindicator of As. In this report, we integrated transcriptomics and metabolomics to investigate genetic and metabolite changes and functional physiological disturbances in C. farreri exposured to inorganic arsenic. Physiological indicators antioxidant factors and cell apoptosis analysis macroscopically corroborated the toxic effects of inorganic arsenic revealed by omics results. Toxic effects of inorganic arsenic on C. farreri were signaling-mediated, causing interference with a variety of cell growth and small molecule metabolism. The results provide evidence that inorganic arsenic disrupts the physiological functions of bivalves, highlighting the correlations between different metabolic pathways and providing new insights into the toxic effects of environmental pollutants on marine organisms.

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.

Exogenously-Sourced Salicylic Acid Imparts Resilience towards Arsenic Stress by Modulating Photosynthesis, Antioxidant Potential and Arsenic Sequestration in Brassica napus Plants

In the current study, salicylic acid (SA) assesses the physiological and biochemical responses in overcoming the potential deleterious impacts of arsenic (As) on Brassica napus cultivar Neelam. The toxicity caused by As significantly reduced the observed growth and photosynthetic attributes and accelerated the reactive oxygen species (ROS). Plants subjected to As stress revealed a significant (p ≤ 0.05) reduction in the plant growth and photosynthetic parameters, which accounts for decreased carbon (C) and sulfur (S) assimilation. Foliar spray of SA lowered the oxidative burden in terms of hydrogen peroxide (H2O2), superoxide anion (O2•-), and lipid peroxidation in As-affected plants. Application of SA in two levels (250 and 500 mM) protected the Brassica napus cultivar from As stress by enhancing the antioxidant capacity of the plant by lowering oxidative stress. Among the two doses, 500 mM SA was most effective in mitigating the adverse effects of As on the Brassica napus cultivar. It was found that SA application to the Brassica napus cultivar alleviated the stress by lowering the accumulation of As in roots and leaves due to the participation of metal chelators like phytochelatins, enhancing the S-assimilatory pathway, carbohydrate metabolism, higher cell viability in roots, activity of ribulose 1, 5-bisphosphate carboxylase (Rubisco), and proline metabolism through the active participation of γ-glutamyl kinase (GK) and proline oxidase (PROX) enzyme. The current study shows that SA has the capability to enhance the growth and productivity of B. napus plants cultivated in agricultural soil polluted with As and perhaps other heavy metals.

Protective mechanisms of sulfur against arsenic phytotoxicity in Brassica napus by regulating thiol biosynthesis, sulfur-assimilation, photosynthesis, and antioxidant response

The contamination of agricultural soils with Arsenic (As) is a significant environmental stress that restricts plant growth, metabolism, and productivity worldwide. The present study examined the role of elemental sulfur (S⁰) in protecting Brassica napus plants from Arsenic (As) toxicity. Arsenic (100, and 200 mg As kg^-1 soil) in soil caused detrimental effects on five Brassica napus cultivars (Neelam, Teri-Uttam Jawahar, Him Sarson, GSC-101, and NUDB 26-11). The As toxicity inhibited the growth and photosynthesis indices in all cultivars with more deterioration effects in NUDB 26-11. Plant absorption and uptake of As caused the generation of oxidative injury by accumulating the reactive oxygen species (ROS), which simultaneously decreased the plant defence capability and ultimately the photosynthesis. Application of sulfur (S⁰, 100 or 200 mg S kg^-1 soil) alleviated the negative impacts and toxicity of As on the photosynthesis and growth matrices of plants, especially under high S level. S⁰ also boosted the antioxidant potential of plants and toned-down lipid peroxidation and ROS aggravation such as superoxide anion (O₂^•-) and H₂O₂, hydrogen peroxide, in As affected plants. In general, S⁰ at 200 mg kg^-1 soil more perceptibly increased the functionality of antioxidant enzymes, and non-enzymatic antioxidants, metal chelators and non-protein thiols. Further amendment of soil with S⁰ at fifteen days before seed sowing affected by As-induced toxic effects (added to soil at the time of sowing) considerably intensified the endogenous hydrogen sulfide (H₂S) content and its regenerating enzymes D-cysteine desulfhydrase (DCD) and L-cysteine desulfhydrase (LCD) that further strengthened the defense capability of plants to withstand As-stress. Our results suggest the role of H₂S in the S-induced defense operation of the B. napus plants in restraining As toxicity. The current study shows that S⁰ as a source of S might be used to promote the growth of B. napus plants in polluted agricultural soils.

Arsenic trioxide increases apoptosis of SK-N-BE (2) cells partially by inducing GPX4-mediated ferroptosis

BACKGROUND

Neuroblastoma (NB) is the most common extracranial tumor in central nervous system threatening children's health with limited therapeutic options. Arsenic trioxide (ATO) has been identified the cytotoxicity in NB cells but the potential mechanism remains unclear. In this study, we attempted to obtain some insight into the mechanisms of cell death induced by ATO in NB cells.

METHODS AND RESULTS

Proteomic analyses found that ATO can affect the signaling pathway associated with ferroptosis, including the upregulation of iron absorption (FTL, FTH1, HO-1), ferritinophagy (LC3, P62, ATG7, NCOA4) and modifier of glutathione synthesis (GCLM); downregulation of glutamine synthetase (GS) and GPX4, which was the critical inhibitor of ferroptosis. Western blot analysis revealing GPX4 expression in SK-N-BE (2) cells decreased after treatment with ATO (7.3 µM), resulting in a loss of GPX4 activity. Furthermore, Ferroptosis inhibitor ferrostatin-1 partially blocked ATO-induced cell death.

CONCLUSIONS

Our study revealed that ATO may induce ferroptosis in neuroblastoma cell SK-N-BE (2) by facilitating the downregulation of GPX4, ultimately resulting in iron-dependent oxidative death.

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.

Zinc Alleviates Arsenic-Induced Inflammation and Apoptosis in the Head Kidney of Common Carp by Inhibiting Oxidative Stress and Endoplasmic Reticulum Stress

Arsenic (As) pollution is ubiquitous in water, which shows immunotoxicity to aquatic organisms. As an indispensable regulator of gene transcription and enzymatic modification, zinc (Zn) may play a preventive and therapeutic effect on As toxicity. The purpose of this study was to investigate the interactions of As and Zn on the head kidney of common carp Cyprinus carpio. Herein the carp were treated alone or in combination with waterborne As³⁺ (2.83 mg/L) and/or Zn²⁺ (1 mg/L). Results suggested a head kidney-toxic effect of As exposure, which was manifested by the histopathological damage of the head kidney, elevation of nuclear translocation of pro-inflammatory nuclear factor-kappa light chain enhancer of B cells (NF-κB), and blockage of the anti-oxidative nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. The global activation of three endoplasmic reticulum (ER) stress pathways led to the execution of programmed cell death, including ER apoptosis mediated by C/EBP-homologous protein (CHOP), death receptor-mediated exogenous cell apoptosis, and the endogenous apoptosis executed by Caspases9. The combined application of Zn can significantly improve the histopathological damage of the head kidney, the imbalance of the antioxidant system, and the apoptosis outcomes due to ER stress. In conclusion, this study indicates that Zn has an antagonistic effect on the head kidney injury of common carp induced by sub-chronic As exposure. The results of this study provide basic data for the risk assessment of As accumulation in an aquatic environment and a reference for the use of Zn preparation in aquaculture.

Newly-synthesized iron-oxide nanoparticles showed synergetic effect with citric acid for alleviating arsenic phytotoxicity in soybean

In the current investigation, we presented the success of the modified hydrothermal method for synthesizing the iron-oxide nanoparticles (Fe2O3-NPs) efficiently. These NPs were further characterized by using different techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM) micrographs, energy-dispersive X-ray spectroscopy (EDAX)/Mapping pattern, Raman Spectroscopy Pattern, ultra violet (UV) and Photoluminescence (PL). All these analyses revealed highly pure nature of Fe2O3-NPs with no internal defects, and suggested its application for plant growth improvement. Therefore, we further investigated the separate as well as combined effects of the Fe2O3-NPs and citric acid (CA) in the alleviation of arsenic (As) toxicity in the soybean (Glycine max L.), by evaluating the different plant growth and metabolic attributes. Results of our study revealed that As-induced growth inhibition, reduction of photosynthesis, water use efficiency (WUE), and reactive oxygen species (ROS) accumulation whereas application of the Fe2O3-NPs and CA significantly reversed all these adverse effects in soybean plants. Moreover, the As-stress induced malondialdehyde (MDA) and hydrogen peroxide (H2O2) production were partially reversed by the Fe2O3-NPs and CA in the As-stressed plants by 16% and 10% (MDA) and 29% and 12% (H2O2). This might have resulted due to the Fe2O3-NPs and CA induced activities of the antioxidant defense in plants. Overall, the Fe2O3-NPs and CA supplementation separately and in combination positively regulated the As tolerance in soybean; however, the effect of the combined application on the As tolerance was more profound relative to the individual application. These results suggested the synergetic effect of the Fe2O3-NPs and CA on the As-tolerance in soybean. However, in-depth mechanism underlying the defense crosstalk between the Fe2O3-NPs and CA needs to be further explored.

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.

Based on Activation of p62-Keap1-Nrf2 Pathway, Hesperidin Protects Arsenic-Trioxide-Induced Cardiotoxicity in Mice

Background: Hesperidin (HES) is a flavonoid glycoside found in the tangerine peel and has antioxidant properties. Arsenic trioxide (ATO) is an anti-tumour drug; however, its serious cardiotoxicity limits its clinical application. In addition, the protection of HES against ATO-induced cardiotoxicity has not been explored.

Objective: The study aims to investigate and identify the underlying effect and mechanism of HES on ATO-induced cardiotoxicity.

Methods: Fifty mice were randomly assigned to five groups. Mice were orally given HES:100 or 300 mg/kg/day concurrently and given ATO intraperitoneal injections: 7.5 mg/kg/day for 1 week. Blood and heart tissues were collected for examination. Evaluated in serum was the levels of creatine kinase (CK), lactate dehydrogenase (LDH) and cardiac troponin I (cTnI). In addition, evaluated in heart tissues were the levels of reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), catalase (CAT), tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6), B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), Caspase-3, cleaved-Caspase-3, p62, Kelch-like ECH-associated protein 1 (Keap1), and nuclear factor erythroid 2-related factor 2 (Nrf2). The heart tissues were also examined for histopathology and mitochondrial ultrastructure.

Results: Compared with the ATO group, the HES treatment groups reduced the levels of CK, LDH, cTnI, ROS, MDA, TNF-α, IL-6, Bax, Caspase-3, cleaved-Caspase-3 and Keap1 and enhanced the levels of SOD, GSH, CAT, Bcl-2, p62 and Nrf2.

Conclusions: The results demonstrate that HES protects against ATO-induced cardiotoxicity, through inhibiting oxidative stress, and subsequent inflammation and apoptosis. The underlying results are closely related to the regulation of the p62-Keap1-Nrf2 signalling pathway.

Exposure to the herbicide butachlor activates hepatic stress signals and disturbs lipid metabolism in mice

Butachlor is a systemic herbicide widely applied on wheat, rice, beans, and different other crops, and is frequently detected in groundwater, surface water, and soil. Therefore, it is necessary to investigate the potential adverse health risks and the underlying mechanisms of hepatotoxicity caused by exposure to butachlor in invertebrates, other nontarget animals, and public health. For this reason, a total of 20 mice were obtained and randomly divided into two groups. The experimental mice in one group were exposed to butachlor (8 mg/kg) and the mice in control group received normal saline. The liver tissues were obtained from each mice at day 21 of the trial. Results indicated that exposure to butachlor induced hepatotoxicity in terms of swelling of hepatocyte, disorders in the arrangement of hepatic cells, increased concentrations of different serum enzymes such as alkaline phosphate (ALP) and aspartate aminotransferase (AST). The results on the mechanisms of liver toxicity indicated that butachlor induced overexpression of Apaf-1, Bax, Caspase-3, Caspase-9, Cyt-c, p53, Beclin-1, ATG-5, and LC3, whereas decreases the expression of Bcl-2 and p62 suggesting abnormal processes of apoptosis and autophagy. Results on different metabolites (61 differential metabolites) revealed upregulation of PE and LysoPC, whereas downregulation of SM caused by butachlor exposure in mice led to the disruption of glycerophospholipids and lipid metabolism in the liver. The results of our experimental research indicated that butachlor induces hepatotoxic effects through disruption of lipid metabolism, abnormal mechanisms of autophagy, and apoptosis that provides new insights into the elucidation of the mechanisms of hepatotoxicity in mice induced by butachlor.

Connections between endoplasmic reticulum stress-associated unfolded protein response, mitochondria, and autophagy in arsenic-induced carcinogenesis

Arsenic exposure in contaminated drinking water is a global health issue, as more than 200 million people are affected globally. Arsenic has been known to cause skin, liver, lung, bladder and prostate cancers. Accordingly, it has been categorized as a group I human carcinogen by the International Agency for Research on Cancer (IARC). Various natural and anthropogenic activities lead to the release of arsenic in the environment, contaminating air, water and food sources. Traditionally, genetic mutations have been the center of cancer research. However, emerging studies have now focused on the importance of epigenetics, metabolism and endoplasmic reticulum (ER) stress in cancer. Arsenic is highly capable of inducing stress in the cells via the generation of free radicals causing oxidative stress, epigenetic and genetic alterations, mitochondrial dysfunction, activation of intracellular signaling pathways, and impairment of autophagy and DNA repair systems. The cancer cells are able to utilize the unfolded protein response (UPR) to overcome these internal stresses in various stages of arsenic-induced carcinogenesis, from cancer growth to immune responses. The UPR is an evolutionarily conserved stress response that has both survival and apoptotic outcomes. PERK, IRE1α and ATF6α are the three ER stress sensors that are activated to maintain cellular proteostasis, which can also promote apoptosis on prolonged ER stress. The dual nature of UPR in different cancer types and stages is a challenge for researchers. We must investigate the role and the connections among ER stress-associated UPR, mitochondrial dysfunction and autophagy in arsenic malignancies to identify key targets for cancer prevention and therapeutics.

Copper exposure induces mitochondrial dynamic disorder and oxidative stress via mitochondrial unfolded protein response in pig fundic gland

Cu is a metallic element that widely spread over in the environment, which have raised wide concerns about the potential toxic effects and public health threat. The objective of this study aimed to investigate the impression of copper (Cu)-triggered toxicity on mitochondrial dynamic, oxidative stress, and unfolded protein response (UPRmt) in fundic gland of pigs. Weaned pigs were randomly distributed into three groups, fed with different Cu of 10 mg/kg (control group), 125 mg/kg (group I), and 250 mg/kg (group Ⅱ). The trial persisted for 80 days and the fundic gland tissues were collected for further researches. Moreover, the markers participated to mitochondrial dynamic, UPRmt，and oxidative stress in fundic gland were determined. Results revealed that vacuolar degeneration were observed in the treated groups contrast with control group, and the Cu level was boosted with the increasing intake of Cu. Besides that, the levels of CAT, TRX, H2O2, and G6PDH were reduced in group Ⅰ and group Ⅱ, the mRNA levels of NRF2, HO-1, SOD-1, CAT, SOD-2, GSR, GPX1, GPX4, and TRX in the treated groups were promoted contrast to control group. Furthermore, the protein expression of KEAP1 was dramatically decreased, and the protein expression of NRF2, TRX and HO-1 were markedly enhanced in group Ⅰ and Ⅱ at 80 days. Moreover, the mRNA and protein expression levels of MFN1, MFN2, and OPA1 down-regulated and protein level of DRP1 was increased with the adding levels of Cu. Nevertheless, the UPRmt-related mRNA levels of CLPP, HTRA-2, CHOP, HSP10, and HSP60 were enhanced dramatically in Cu treatment group compared with control group. In general, our current study demonstrated that excessive absorption of Cu in fundic gland were related with stimulating UPRmt, oxidative stress, and the NRF2 interceded antioxidant defense. These results could afford an updated evidence on molecular theory of Cu-invited toxicity.

Zearalenone exposure mediated hepatotoxicity via mitochondrial apoptotic and autophagy pathways: Associated with gut microbiome and metabolites

Zearalenone (ZEN), a mycotoxin is frequently detected in different food products and has been widely studied for its toxicity. However, the underlying mechanisms of hepatotoxic effects, relationship between gut microbiome and liver metabolite mediated hepatotoxicity mechanisms induced by ZEN are still not clear. Here, we reported that the different microscopic changes like swelling of hepatocyte, disorganization of hepatocytes and extensive vacuolar degeneration were observed, and the mitochondrial functions decreased in exposed mice. Results exhibited up-regulation in expression of signals of apoptosis and autophagy in liver of treated mice via mitochondrial apoptotic and autophagy pathway (Beclin1/p62). The diversity of gut microbiome decreased and the values of various microbiome altered in treated mice, including 5 phyla (Chloroflexi, Sva0485, Methylomirabilota, MBNT15 and Kryptonia) and genera (Frankia, Lactococcus, Anaerolinea, Halomonas and Sh765B-TzT-35) significantly changed. Liver metabolism showed that the concentrations of 91 metabolite including lipids and lipid like molecules were significantly changed. The values of phosphatidylcholine, 2-Lysophosphatidylcholine and phosphatidate concentrations suggestive of abnormal glycerophosphate metabolism pathway were significantly increased in mice due to exposure to ZEN. In conclusion, the findings suggest that the disorders in gut microbiome and liver metabolites due to exposure to ZEN in mice may affect the liver.

Arsenic and antimony co-induced nephrotoxicity via autophagy and pyroptosis through ROS-mediated pathway in vivo and in vitro

Arsenic (As) and antimony (Sb) are commonly accumulated environmental pollutants that often coexist in nature and cause serious widespread biological toxicity. To investigate the nephrotoxicity induced by As and Sb in detail, we explored the mechanism by which As and Sb cotreatment induced autophagy and pyroptosis in vivo and in vitro. In this study, mice were treated with 4 mg/kg arsenic trioxide (ATO) or/and 15 mg/kg antimony trichloride (SbCl₃) by intragastric intubation for 60 days. TCMK-1 cells were treated with ATO (12.5 μM), SbCl₃ (25 μM) or a combination of As and Sb for 24 h. The results of the in vivo experiment demonstrated that As or/and Sb exposure could induce histopathological changes in the kidneys, and increase the levels of biochemical indicators of nephrotoxicity. In addition, As and Sb can co-induce oxidative stress, which further activate autophagy and pyroptosis. In an in vitro experiment, As and/or Sb coexposure increased ROS generation and decreased MMP. Moreover, the results of related molecular experiments further confirmed that As and Sb coactivated autophagy and pyroptosis. In conclusion, our results indicated that As and Sb co-exposure could cause autophagy and pyroptosis via the ROS pathway, and these two metals might have a synergistic effect on nephrotoxicity.

Exposure to Fluoride induces apoptosis in liver of ducks by regulating Cyt-C/Caspase 3/9 signaling pathway

Fluorine being a well-known and essential element for normal physiological functions of tissues of different organisms is frequently used for growth and development of body. The mechanisms of adverse and injurious impacts of fluoride are not clear and still are under debate. Therefore, this study was executed to ascertain the potential mechanisms of sodium fluoride in liver tissues of ducks. For this purpose, a total of 14 ducks were randomly divided and kept in two groups including control group and sodium fluoride treated group. The ducks in control group were fed with normal diet while the ducks in other group were exposed to sodium fluoride (750 mg/kg) for 28 days. The results showed that exposure to sodium fluoride induced deleterious effects in different liver tissues of ducks. The results indicated that mRNA levels of Cas-3, Cas-9, p53, Apaf-1, Bax and Cyt-c were increased in treated ducks with significantly higher mRNA level of Cas-9 and lower levels of the mRNA level of Bcl-2 as compared to untreated control group (P < 0.01). The results showed that protein expression levels of Bax and p53 were increased while protein expression level of Bcl-2 was reduced in treated ducks. No difference was observed in protein expression level of Cas-3 between treated and untreated ducks. The results of this study suggest that sodium fluoride damages the normal structure of liver and induces abnormal process of apoptosis in hepatocyte, which provide a new idea for elucidating the mechanisms of sodium fluoride induced hepatotoxicity in ducks.

Prepubertal arsenic exposure alters phosphoproteins profile, quality, and fertility of epididymal spermatozoa in sexually mature rats

Arsenic intoxication affects male reproductive parameters of prepubertal rats. Besides, morphological and functional alterations in their testis and epididymis may remain after withdrawal of arsenic insult, causing potential impairment in male fertility during adulthood. In this study, we aimed at analyzing the effect of prepubertal arsenic exposure on the fecundity of epididymal sperm from sexually mature Wistar rats, assessing fertility indexes, sperm parameters, and sperm phosphoproteins content. Male pups on postnatal day (PND) 21 received filtered water (controls, n = 10) and 10 mg L^-1 arsenite (n = 10) daily for 30 days. From PND52 to PND81, rats from both groups received filtered water. During this period, the males mated with non-exposed females between PND72 and PND75. Our results showed that sexually mature rats presented low sperm production, epididymal sperm count, motility, and quality after prepubertal arsenic exposure. These findings possibly contributed to the low fertility potential and high preimplantation loss. Epididymal sperm proteome detected 268 proteins, which 170 were found in animals from both control and arsenic groups, 27 proteins were detected only in control animals and 71 proteins only in arsenic-exposed rats. In these animals, SPATA 18 and other five proteins were upregulated, whereas keratin type II cytoskeletal 1 was downregulated (q < 0.1). The results of KEGG pathway analysis demonstrated an enrichment of pathways related to dopaminergic response, adrenergic signaling, protein degradation, and oocyte meiosis in arsenic-exposed animals. Moreover, 26 proteins were identified by phosphoproteomic with different phosphorylation pattern in animals from both groups, but SPATA18 was phosphorylated only in arsenic-exposed animals. We concluded that prepubertal exposure to arsenic is deleterious to sperm quality and male fertility, altering the sperm phosphoproteins profile.

Protective effects of curcumin on ATO-induced nephrotoxicity in ducks in relation to suppressed autophagy, apoptosis and dyslipidemia by regulating oxidative stress

Arsenic trioxide (ATO) has been known as common environmental pollution, and is deemed to a threat to global public health. Curcumin (Cur) is a phytoconstituent, which has been demonstrated to have antioxidant effects. In the current experiment, we investigated the efficacy of Cur against ATO-induced kidney injury and explored the potential molecular mechanisms that have not yet been fully elucidated in ducks. The results showed that treatment with Cur attenuated ATO-induced body weight loss, reduced the content of ATO in the kidney, and improved ATO-induced kidney pathological damage. Cur also remarkably alleviated the ascent of ATO-induced MDA level and activated the Nrf2 pathway. Using the TEM, we found Cur relieved mitochondrial swelling, autolysosomes generating and nuclear damage. Simultaneously, Cur was found that it not only significantly reduced autophagy-related mRNA and protein levels (mTOR, LC3-Ⅰ, LC3-Ⅱ, Atg-5, Beclin1, Pink1 and Parkin) and but also decreased apoptosis-related mRNA and protein expression levels (cleaved caspase-3, Cytc, p53 and Bax). Furthermore, through nontargeted metabolomics analysis, we observed that lipid metabolism balance was disordered by ATO exposure, while Cur administration alleviated the disturbance of lipid metabolism. These results showed ATO could induce autophagy and apoptosis by overproducing ROS in the kidney of ducks, and Cur might relieve excessive autophagy, apoptosis and disturbance of lipid metabolism by regulating oxidative stress. Collectively, our findings explicate the potential therapeutic value of Cur as a new strategy to a variety of disorders caused by ATO exposure.

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

Arsenic and antimony are coexisting cumulative environmental pollutants that cause severe and extensive biological toxicity. However, their interactions and toxic mechanisms in the liver remain to be fully elucidated. In this study, a total of sixty 4-week-old mice were divided into four groups and treated with 4 mg/kg arsenic trioxide (ATO) or/and 15 mg/kg antimony (Sb) for 60 days. The results demonstrated that biochemical indicators of hepatotoxicity (ALT, AST, ALP) were upregulated in all treated groups. Additionally, the oxidative burden of the liver was increased in the cotreated groups compared with the individual toxicant-treated groups. Meanwhile, mitochondrial injury, autophagosomes, hepatic-congestion and karyopyknosis were obviously observed in cotreated groups. Additionally, coupled with serum biochemical index (TG, TC), histopathology examination and metabolomics results, we found that cotreatment with ATO and Sb resulted in lipid metabolism disorder and steatosis of liver tissues. Our further investigation found that the levels of pro-apoptotic (Caspase-3, Caspase-9, Bax, P53, Cytc) and mitophagy (LC3-B, P62, PINK1, Parkin) indexes in the cotreated groups were markedly increased, whereas the levels of anti-apoptosis index (Bcl-2) were decreased. Collectively, these results show that co-exposure to ATO and Sb can cause abnormal liver energy metabolism and oxidative stress. Moreover, mitophagy and apoptosis play important roles in the mechanisms of arsenic/antimony cytotoxicity to mouse livers.

Metabolomics and transcriptomics indicated the molecular targets of copper to the pig kidney

Copper poses huge environmental and public health concerns due to its widespread and persistent use in the past several decades. Although it is well established that at higher levels copper causes nephrotoxicity, the exact mechanisms of its toxicity is not fully understood. Therefore, this experimental study for the first time investigates the potential molecular mechanisms including transcriptomics, metabolomics, serum biochemical, histopathological, cell apoptosis and autophagy in copper-induced renal toxicity in pigs. A total of 14 piglets were randomly assigned to two group (7 piglets per group) and treated with a standard diet (11 mg CuSO4 per kg of feed) and a high copper diet (250 mg CuSO4 per kg of feed). The results of serum biochemical tests and renal histopathology suggested that 250 mg/kg CuSO4 in the diet significantly increased serum creatinine (CREA) and induced renal tubular epithelial cell swelling. Results on transcriptomics and metabolomics showed alteration in 804 genes and 53 metabolites in kidneys of treated pigs, respectively. Combined analysis of transcriptomics and metabolomics indicated that different genes and metabolism pathways in kidneys of treated pigs were involved in glycerophospholipids metabolism and glycosphingolipid metabolism. Furthermore, copper induced mitochondrial apoptosis characterized by increased bax, bak, caspase 3, caspase 8 and caspase 9 expressions while decreased bcl-xl and bcl2/bax expression. Exposure to copper decreased the autophagic flux in terms of increased number of autophagosomes, beclin1 and LC3b/LC3a expression and p62 accumulation. These results indicated that the imbalance of glycosphingolipid metabolism, the impairment of autophagy and increase mitochondrial apoptosis play an important role in copper induced renal damage and are useful mechanisms to understand the mechanisms of copper nephrotoxicity.

Mechanisms underlying the protective effect of tannic acid against arsenic trioxide‑induced cardiotoxicity in rats: Potential involvement of mitochondrial apoptosis

Arsenic trioxide (ATO) is a frontline chemotherapy drug used in the therapy of acute promyelocytic leukemia. However, the clinical use of ATO is hindered by its cardiotoxicity. The present study aimed to observe the potential effects and underlying mechanisms of tannic acid (TA) against ATO-induced cardiotoxicity. Male rats were intraperitoneally injected with ATO (5 mg/kg/day) to induce cardiotoxicity. TA (20 and 40 mg/kg/day) was administered to evaluate its cardioprotective efficacy against ATO-induced heart injury in rats. Administration of ATO resulted in pathological damage in the heart and increased oxidative stress as well as levels of serum cardiac biomarkers creatine kinase and lactate dehydrogenase and the inflammatory marker NF-κB (p65). Conversely, TA markedly reversed this phenomenon. Additionally, TA treatment caused a notable decrease in the expression levels of cleaved caspase-3/caspase-3, Bax, p53 and Bad, while increasing Bcl-2 expression levels. Notably, the application of TA decreased the expression levels of cytochrome c, second mitochondria-derived activator of caspases and high-temperature requirement A2, which are apoptosis mitochondrial-associated proteins. The present findings indicated that TA protected against ATO-induced cardiotoxicity, which may be associated with oxidative stress, inflammation and mitochondrial apoptosis.

Integration of transcriptomic and metabolomic data reveals metabolic pathway alteration in mouse spermatogonia with the effect of copper exposure

Copper is a widespread heavy metal in environment and has toxic effects when exposed. However, study of copper-induced male reproductive toxicity is still insufficient to report, and the underlying mechanisms are unknown. Keeping in view, RNA-Seq and metabolomic were performed to identify metabolic pathways that were distressed in mouse spermatogonia with the effect of copper sulfate, and the integrated analysis of the mechanism of copper administered GC-1 cells from metabolomic and transcriptomic data. Our results demonstrated that many genes and metabolites were regulated in the copper sulfate-treated cells. The differential metabolites analysis showed that 49 and 127 metabolites were significantly different in ESI+ and ESI- mode, respectively. Meanwhile, a total of 2813 genes were up-regulated and 2488 genes were down-regulated in the treatment groups compared to those in the control groups. Interestingly, ophthalmic acid and gamma glutamylleucine were markedly increased by copper treatment in two modes. By integrating with transcriptomic and metabolomic data, we revealed that 37 and 22 most related pathways were over-enriched in ESI+ and ESI- mode, respectively. Whereas, amino acid biosynthesis and metabolism play essential role in the potential relationship between DEGs and metabolites, which suggests that amino acid biosynthesis and metabolism may be the major metabolic pathways disturbed by copper in GC-1 cells. This study provides important clues and evidence for understanding the mechanisms responsible for copper-induced male spermatogenesis toxicity, and useful biomarkers indicative of copper exposure could be discovered from present study.

Arsenic induces mTOR-dependent autophagy, whereas it impairs the autophagy-lysosome pathway and the potential role of TFEB in cultured dendritic cells

Arsenic is a toxic metalloid, which also compromises immunity and causes various immunological disorders. Exposure to arsenic exerts the immunosuppressive properties of dendritic cells (DCs). Autophagy is a self-renewal process of cells, which degrades damaged macromolecules and organelles through the lysosomal pathway. Thus, herein, we attempt to clarify the impacts of autophagy and the autophagy-lysosome pathway on arsenic-exposed DCs. Bone marrow-derived dendritic cells (BMDCs) were exposed to different concentrations of arsenic (0.25, 0.5 and 1 μM) with or without LPS stimulation. Initially, we observed that arsenic induced autophagosome accumulation, significantly enhanced the LC3 II and p62 expressions and down-regulated the p-mTOR protein levels. We also determined that arsenic-induced autophagy occurred via an mTOR pathway. The results further revealed that arsenic inhibited autophagic flux in LPS-stimulated BMDCs using the autophagy inhibitor chloroquine (CQ). Meanwhile, arsenic significantly decreased the number of lysosomes, protein expression of lysosomal-specific markers LAMP1 and LAMP2, and the protein levels of lysosomal cysteine cathepsins (CTSD and CTSL). Moreover, the overexpression of transcription factor EB (TFEB), the master transcriptional regulator of autophagy and lysosome biogenesis, partially relieved arsenic-inhibited lysosomal CTSD and CTSL expressions, recovered the disorder of autophagic flux, promoted the production of pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and IL-12, and reduced anti-inflammatory cytokine IL-10 secretion. In summary, our results support the idea that arsenic induces autophagy through an mTOR-dependent pathway in cultured BMDCs. Meanwhile, arsenic weakens the process of autophagic flux, which may be partially due to lysosomal dysfunction. Furthermore, we also suggest that TFEB can positively act on the autophagy-lysosome pathway and influence the expression of immunocytokines in DCs.