Cadmium induces reactive oxygen species generation and lipid peroxidation in cortical neurons in culture

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: the biology of a neglected disease

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic, debilitating disease characterised by a wide range of symptoms that severely impact all aspects of life. Despite its significant prevalence, ME/CFS remains one of the most understudied and misunderstood conditions in modern medicine. ME/CFS lacks standardised diagnostic criteria owing to variations in both inclusion and exclusion criteria across different diagnostic guidelines, and furthermore, there are currently no effective treatments available. Moving beyond the traditional fragmented perspectives that have limited our understanding and management of the disease, our analysis of current information on ME/CFS represents a significant paradigm shift by synthesising the disease's multifactorial origins into a cohesive model. We discuss how ME/CFS emerges from an intricate web of genetic vulnerabilities and environmental triggers, notably viral infections, leading to a complex series of pathological responses including immune dysregulation, chronic inflammation, gut dysbiosis, and metabolic disturbances. This comprehensive model not only advances our understanding of ME/CFS's pathophysiology but also opens new avenues for research and potential therapeutic strategies. By integrating these disparate elements, our work emphasises the necessity of a holistic approach to diagnosing, researching, and treating ME/CFS, urging the scientific community to reconsider the disease's complexity and the multifaceted approach required for its study and management.

The leachate from the Urban Solid Waste Transfer Station produces neurotoxicity in Wistar rats

Leachate from municipal solid waste is a mixture of xenobiotics capable of contaminating bodies of water and causing damage to the health of living beings that inhabit or consume contaminated water. A previous study revealed the presence of heavy metals in Urban Solid Waste Transfer Station (USWTS) leachate above the permissible national and international limits. In the present study, we demonstrate that subchronic oral administration (5 and 25 % v/v) of leachate to male Wistar rats caused changes in the immunoreactivity of the glial markers: GFAP and Iba-1, accompanied by an increase in the expression of caspase-3, and a decrease in the expression of the NeuN protein. Results indicate that the heavy metals present in the leachate induced neuronal loss in the prefrontal cortex, suggesting that these contaminants can cause neurological problems in mammals that consume surface water with xenobiotics, since the leachate could contaminate water bodies and underground water.

Caffeic acid attenuates memory dysfunction and restores the altered activity of cholinergic, monoaminergic and purinergic in brain of cadmium chloride exposure rats

OBJECTIVES

This study aims to evaluate the neuroprotective effect of caffeic acid (CAF) against cadmium chloride (CdCl2) in rats via its effect on memory index as well as on altered enzymatic activity in the brain of CdCl2-induced neurotoxicity.

METHODS

The experimental rats were divided into seven groups (n=6 rats per group) of healthy rats (group 1), CdCl2 -induced (CD) (3 mg/kg BW) rats (group 2), CD rats + Vitamin C (group 3), CD rats + CAF (10 and 20 mg/kg BW respectively) (group 4 & 5), and healthy rat + CAF (10 and 20 mg/kg BW respectively) (group 6 & 7). Thereafter, CdCl2 and CAF were administered orally to the experimental rats in group 2 to group 5 on daily basis for 14 days. Then, the Y-maze test was performed on the experimental rats to ascertain their memory index.

RESULTS

CdCl2 administration significantly altered cognitive function, the activity of cholinesterase, monoamine oxidase, arginase, purinergic enzymes, nitric oxide (NOx), and antioxidant status of Cd rats (untreated) when compared with healthy rats. Thereafter, CD rats treated with vitamin C and CAF (10 and 20 mg/kg BW) respectively exhibited an improved cognitive function, and the observed altered activity of cholinesterase, monoamine oxidase, arginase, purinergic were restored when compared with untreated CD rats. Also, the level of brain NOx and antioxidant status were significantly (p<0.05) enhanced when compared with untreated CD rats. In the same vein, CAF administration offers neuro-protective effect in healthy rats vis-à-vis improved cognitive function, reduction in the activity of some enzymes linked to the progression of cognitive dysfunction, and improved antioxidant status when compared to healthy rats devoid of CAF.

CONCLUSIONS

This study demonstrated the neuroprotective effect of CAF against CdCl2 exposure and in healthy rats.

Oxidative Stress in Breast Cancer: A Biochemical Map of Reactive Oxygen Species Production

This review systematizes information about the metabolic features of breast cancer directly related to oxidative stress. It has been shown those redox changes occur at all levels and affect many regulatory systems in the human body. The features of the biochemical processes occurring in breast cancer are described, ranging from nonspecific, at first glance, and strictly biochemical to hormone-induced reactions, genetic and epigenetic regulation, which allows for a broader and deeper understanding of the principles of oncogenesis, as well as maintaining the viability of cancer cells in the mammary gland. Specific pathways of the activation of oxidative stress have been studied as a response to the overproduction of stress hormones and estrogens, and specific ways to reduce its negative impact have been described. The diversity of participants that trigger redox reactions from different sides is considered more fully: glycolytic activity in breast cancer, and the nature of consumption of amino acids and metals. The role of metals in oxidative stress is discussed in detail. They can act as both co-factors and direct participants in oxidative stress, since they are either a trigger mechanism for lipid peroxidation or capable of activating signaling pathways that affect tumorigenesis. Special attention has been paid to the genetic and epigenetic regulation of breast tumors. A complex cascade of mechanisms of epigenetic regulation is explained, which made it possible to reconsider the existing opinion about the triggers and pathways for launching the oncological process, the survival of cancer cells and their ability to localize.

Mitochondrial administration alleviates lead- and cadmium-induced toxicity in rat renal cells

The role of heavy metals such as lead (Pb) and cadmium (Cd) in the etiology of many diseases has been proven. Also, these heavy metals can affect the normal mitochondrial function. Mitochondrial administration therapy is one of the methods used by researchers to help improve mitochondrial defects and diseases. The use of isolated mitochondria as a therapeutic approach has been investigated in in vivo and in vitro studies. Accordingly, in this study, the effects of mitochondrial administration on the improvement of toxicity caused by Pb and Cd in renal proximal tubular cells (RPTC) have been investigated. The results showed that treatment to Pb and Cd caused an increase in the level of free radicals, lipid peroxidation (LPO) content, mitochondrial and lysosomal membrane damage, and also a decrease in the reduced glutathione content in RPTC. In addition, reports have shown an increase in oxidized glutathione content and changes in energy (ATP) levels. Following, the results have shown the protective role of mitochondrial administration in improving the toxicity caused by Pb and Cd in RPTC. Furthermore, the mitochondrial internalization into RPT cells is mediated through actin-dependent endocytosis. So, it could be suggested that the treatment of Pb- and Cd-induced cytotoxicity in RPTC could be carried out through mitochondria administration.

Cadmium neurotoxicity and therapeutic strategies

Cadmium (Cd) is a multitarget, carcinogenic, nonessential environmental pollutant. Due to its toxic effects at very low concentrations, lengthy biological half-life, and low excretion rate, exposure to Cd carries a concern. Prolonged exposure to Cd causes severe injury to the nervous system of both humans and animals. Nevertheless, the precise mechanisms responsible for the neurotoxic effects of Cd have yet to be fully elucidated. The accurate chemical mechanism potentially entails the destruction of metal-ion homeostasis, inducing oxidative stress, apoptosis, and autophagy. Here we review the evidence of the neurotoxic effects of Cd and corresponding strategies to protect against Cd-induced central nervous system injury.

Role of SIRT1 in Potentially Toxic Trace Elements (Lead, Fluoride, Aluminum and Cadmium) Associated Neurodevelopmental Toxicity

The formation of the central nervous system is a meticulously planned and intricate process. Any modification to this process has the potential to disrupt the structure and operation of the brain, which could result in deficiencies in neurological growth. When neurotoxic substances are present during the early stages of development, they can be exceptionally dangerous. Prenatally, the immature brain is extremely vulnerable and is therefore at high risk in pregnant women associated with occupational exposures. Lead, fluoride, aluminum, and cadmium are examples of possibly toxic trace elements that have been identified as an environmental concern in the aetiology of a number of neurological and neurodegenerative illnesses. SIRT1, a member of the sirtuin family has received most attention for its potential neuroprotective properties. SIRT1 is an intriguing therapeutic target since it demonstrates important functions to increase neurogenesis and cellular lifespan by modulating multiple pathways. It promotes axonal extension, neurite growth, and dendritic branching during the development of neurons. Additionally, it contributes to neurogenesis, synaptic plasticity, memory development, and neuroprotection. This review summarizes the possible role of SIRT1 signalling pathway in potentially toxic trace elements -induced neurodevelopmental toxicity, highlighting some molecular pathways such as mitochondrial biogenesis, CREB/BDNF and PGC-1α/NRF1/TFAM.

Juggling cadmium detoxification and zinc homeostasis: A division of labour between the two C. elegans metallothioneins

The chemical properties of toxic cadmium and essential zinc are very similar, and organisms require intricate mechanisms that drive selective handling of metals. Previously regarded as unspecific "metal sponges", metallothioneins (MTLs) are emerging as metal selectivity filters. By utilizing C. elegans mtl-1 and mtl-2 knockout strains, metal accumulation in single worms, single copy fluorescent-tagged transgenes, isoform specific qPCR and lifespan studies it was possible to demonstrate that the handling of cadmium and zinc by the two C. elegans metallothioneins differs fundamentally: the MTL-2 protein can handle both zinc and cadmium, but when it becomes unavailable, either via a knockout or by elevated cadmium exposure, MTL-1 takes over zinc handling, leaving MTL-2 to sequester cadmium. This division of labour is reflected in the folding behaviour of the proteins: MTL-1 folded well in presence of zinc but not cadmium, the reverse was the case for MTL-2. These differences are in part mediated by a zinc-specific mononuclear His3Cys site in the C-terminal insertion of MTL-1; its removal affected the entire C-terminal domain and may shift its metal selectivity towards zinc. Overall, we uncover how metallothionein isoform-specific responses and protein properties allow C. elegans to differentiate between toxic cadmium and essential zinc.

Higher temperature and daily fluctuations aggravate clothianidin toxicity towards Limnodrilus hoffmeisteri

In nature, aquatic organisms may suffer from chemical pollution, together with thermal stress resulted from global warming. However, limited information is available on the combined effects of pesticide with climate change on aquatic organisms. In this study, the acute toxicity of clothianidin to Limnodrilus hoffmeisteri as well as its effect on the induction of oxidative stress under both constant temperature and daily temperature fluctuation (DTF) regimes was investigated. Results showed that clothianidin exhibited the minimal toxicity to L. hoffmeisteri at 25 °C, which was magnified by both increased or decreased temperatures and 10 °C DTF. At different temperatures (15 °C, 25 °C and 35 °C), clothianidin exposure led to the elevated reactive oxygen species (ROS) levels and activated the antioxidant enzymes to resist against the oxidative stress. However, the antioxidant response induced by clothianidin was overwhelmed at high temperature as evidenced by decreased glutathione (GSH) content. Significant elevation of catalase (CAT) and peroxidase (POD) activities but depletion of GSH was also observed in worms treated with clothianidin under DTF after 24 h. The results indicated that high temperature and DTF could aggravate the clothianidin-induced oxidative stress. Moreover, the critical thermal maximum (CTmax) of the worms decreased with the increasing clothianidin concentrations, suggesting that exposure to clothianidin could reduce the heat tolerance of L. hoffmeisteri. Our work highlights the crucial importance to integrate temperature changes into risk assessment of pesticides under global warming.

Arrestin domain-containing protein 1-mediated microvesicles (ARMMs) protect against cadmium-induced neurotoxicity

Exposure to environmental heavy metals such as cadmium (Cd) is often linked to neurotoxicity but the underlying mechanisms remain poorly understood. Here we show that Arrestin domain-containing protein 1 (ARRDC1)-mediated microvesicles (ARMMs)--an important class of extracellular vesicles (EVs) whose biogenesis occurs at the plasma membrane--protect against Cd-induced neurotoxicity. Cd increased the production of EVs, including ARMMs, in a human neural progenitor cell line, ReNcell CX (ReN) cells. ReN cells that lack ARMMs production as a result of CRISPR-mediated ARRDC1 knockout were more susceptible to Cd toxicity as evidenced by increased LDH production as well as elevated level of oxidative stress markers. Importantly, adding ARMMs back to the ARRDC1-knockout ReN cells significantly reduced Cd-induced toxicity. Consistent with this finding, proteomics data showed that anti-oxidative stress proteins are enriched in ARMMs secreted from ReN cells. Together our study reveals a novel protective role of ARMMs in Cd neurotoxicity and suggests that ARMMs may be used therapeutically to reduce neurotoxicity caused by exposure to Cd and potentially other metal toxicants.

Effects of arsenic exposure on trace element levels in the hippocampus and cortex of rats and their gender differences

BACKGROUND

Exposure to arsenic (As) is a major public health challenge worldwide. Chronic exposure to As can cause various human health effects, including skin diseases, cardiovascular disease, neurological disorders, and cancer. Studies have shown that As exposure can lead to disturbances in the balance of trace elements in the body. Moreover, As readily crosses the blood-brain barrier and can be enriched in the hippocampus and cortex, causing neurotoxic damage. At present, there are few reports on the effect of As on trace element levels in the central nervous system (CNS). Therefore, we sought to explore As-induced neurotoxicity and the effects of As on CNS trace element levels.

METHODS

An As-induced neurological injury model in rats was established by feeding As chow for 90 days of continuous exposure, and 19 elements were detected in the hippocampus and cortex of As-exposed rats by inductively coupled plasma mass spectrometry.

RESULTS

The results showed that the As levels in the hippocampus and cortex of As-exposed rats were significantly higher than those in the control group, The As levels in the cortex were significantly higher than in the hippocampus group. The levels of Cd, Ho, and Rb were increased in the hippocampus and decreased in Au, Ba, Ce, Cs, Pd, Se, Sr, and Tl in the As-exposed group, while the levels of Cd and Rb were increased and Se and Au were decreased in the cortex. Significant gender differences in the effects of As on hippocampal Cd, Ba, Rb, and Sr, and cortical Cd and Mo.

CONCLUSION

It is suggested that elemental imbalance may be a risk factor for developing As toxicity plays a synergistic or antagonistic role in As-induced toxicity and is closely related to As-induced CNS damage.

Immunostimulatory and anti-inflammatory impact of Fragaria ananassa methanol extract in a rat model of cadmium chloride-induced pulmonary toxicity

Cadmium is an extremely dangerous heavy metal that can lead to disastrous consequences in all organisms. Several natural remedies reduce the toxicities of experimentally generated metals in animals. Strawberry Fragaria ananassa contains several bioactive compounds that may mitigate heavy-metal toxicity. The study aim was to evaluate the ability of a strawberry fruit methanol extract (SE) to reduce Cd toxicity and to identify and quantify the active constituents of SE. Forty Wistar rats were classified into four groups: the control group- 1 ml saline IP; SE group- 100 mg of SE/kg rats orally; cadmium (Cd) group-2 mg CdCl2/kg body weight/IP daily; and treated group- SE given 1 hour before Cd administration. Administration of Cd induced several histopathological and immunohistochemical alterations in lung sections. Biochemical analysis of lung homogenates and mRNA levels of antioxidants and inflammatory cytokines indicated significant changes to the risk profile. SE administration significantly decreased the oxidative stress, inflammation, tissue damage, the mean area percentage of collagen fibers, and positive immuno-expressions of TNF-α and NF-κB induced by CdCl2. Moreover, the MDA, TNF-α, GM-CSF, and IL-1β levels in Cd-exposed rat lung tissue were significantly lower in the SE-treated group than in the Cd-group. SE significantly augmented lung GSH, SOD, HO-1, GPx-2, and Nrf2 levels in Cd-exposed rats. SE mitigated Cd-caused oxidative stress and lung inflammation. Therefore, regularly consuming a strawberry-rich diet could benefit general health and help prevent and treat diseases.

Associations of cadmium exposure with risk of metabolic syndrome and its individual components: a meta-analysis

Data directly associating cadmium (Cd) with metabolic syndrome (MetS) are sparse and inconsistent. We aimed to quantitatively assess the association of Cd exposure with risk of MetS and its individual components. Literature searching was performed in PubMed, EMBASE, and MEDLINE-OVID through September, 2021. Weighted odds ratios (ORs) for MetS and its components were pooled by comparing the highest to the lowest category of Cd exposure using random-effects models. Eleven (10 from Asia and 1 from the US) cross-sectional studies (33,887 participants and 7176 cases) were identified. Overall, Cd exposure was not associated with risk of MetS [OR: 1.08, 95% confidence interval (CI): 0.92, 1.28]. However, the association became significant when pooling Asian studies (OR: 1.18, 95% CI: 1.02, 1.35), and it was more pronounced with Cd measured in blood (OR: 1.24, 95% CI: 1.05, 1.45). Additionally, Cd exposure was significantly associated with reduced HDL-cholesterol (OR: 1.27, 95% CI: 1.05, 1.54) and elevated triglyceride (OR: 1.17, 95% CI: 1.05, 1.30), but not other components. This meta-analysis indicates that Cd exposure is associated with risk of MetS among Asian populations, which is mainly explained by Cd's association with dyslipidemia. Further studies are needed to better understand the mechanism of action.

Mirtazapine attenuated cadmium-induced neuronal intoxication by regulating Nrf2 and NF-κB/TLR4 signals

Cadmium (Cd) is one of the most hazardous metals to the environment and human health. Neurotoxicity is of the most serious hazards caused by Cd. Mirtazapine (MZP) is a central presynaptic α2 receptor antagonist used effectively in treating several neurological disorders. This study investigated the anti-inflammatory and antioxidant activity of MZP against Cd-induced neurotoxicity. In this study, rats were randomly divided into five groups: control, MZP (30 mg/kg), Cd (6.5 mg/kg/day; i.p), Cd + MZP (15 mg/kg), and Cd + MZP (30 mg/kg). Histopathological examination, oxidative stress biomarkers, inflammatory cytokines, and the impact of Nrf2 and NF-κB/TLR4 signals were assessed in our study. Compared to Cd control rats, MZP attenuated histological abrasions in the cerebral cortex and CA1 and CA3 regions of the hippocampus as well as the dentate gyrus. MZP attenuated oxidative injury by upregulating Nrf2. In addition, MZP suppressed the inflammatory response by decreasing TNF-α, IL-1β, and IL-6 mediated by downregulating TLR4 and NF-κB. It is noteworthy that MZP's neuroprotective actions were dose-dependent. Collectively, MZP is a promising therapeutic strategy for attenuating Cd-induced neurotoxicity by regulating Nrf2, and NF-κB/TLR4 signals, pending further study in clinical settings.

Synergetic effects of polyethylene microplastic and abamectin pesticides on the eyes of zebrafish larvae and adults through activation of apoptosis signaling pathways

Although the toxicity of microplastics (MPs) and pesticides has recently been described, the possible effects of combining these pollutants are poorly understood. Thus, we evaluated the potential impact of exposure to polyethylene MP (PE-MP) and abamectin (ABM) (alone and combined) in zebrafish. After five days, the combined exposure to MP and ABM decreased the survival rate compared to exposures to individual pollutants. A significant increase in reactive oxygen species (ROS), lipid peroxidation, apoptosis, and impairment in antioxidant response was observed in zebrafish larvae. Morphological changes in the eyes of zebrafish significantly increased in the combined exposure group than in the individual exposure. Furthermore, the bax and p53 expression (specific apoptotic genes) was significantly upregulated after the combined exposure to PE-MP and ABM. So, the synergetic effect of MP and ABM cannot be ignored, and further research on other higher models is required to confirm its consequences.

Cadmium aggravates the blood-brain barrier disruption via inhibition of the Wnt7A/β-catenin signaling axis

Cadmium (Cd) is a non-biodegradable widespread environmental pollutant, which can cross the blood-brain barrier (BBB) and cause cerebral toxicity. However, the effect of Cd on the BBB is still unclear. In this study, a total of 80 (1-day-old) Hy-Line white variety chicks (20 chickens/group) were selected and randomly divided into four (4) groups: the control group (Con group) (fed with a basic diet, n = 20), the Cd 35 group (basic diet with 35 mg/kg CdCl₂, n = 20), the Cd 70 group (basic diet with 70 mg/kg CdCl₂, n = 20) and the Cd 140 group (basic diet with 140 mg/kg CdCl₂, n = 20), and fed for 90 days. The pathological changes, factors associated with the BBB, oxidation level and the levels of Wingless-type MMTV integration site family, member 7 A (Wnt7A)/Wnt receptor Frizzled 4 (FZD4)/β-catenin signaling axis-related proteins in brain tissue were detected. Cd exposure induced capillary damage and neuronal swelling, degeneration and loss of neurons. Gene Set Enrichment Analysis (GSEA) showed the weakened Wnt/β-catenin signaling axis. The protein expression of the Wnt7A, FZD4, and β-catenin was decreased by Cd expusure. Inflammation generation and BBB dysfunction were induced by Cd, as manifested by impaired tight junctions (TJs) and adherens junctions (AJs) formation. These findings underscore that Cd induced BBB dysfunction via disturbing Wnt7A/FZD4/β-catenin signaling axis.

Minocycline Protects PC12 Cells Against Cadmium-Induced Neurotoxicity by Modulating Apoptosis

Cadmium (Cd) is a well-known heavy metal and a neurotoxic agent. Minocycline (Mino) is an anti-microbial agent with a lipophilic structure that crosses the blood-brain barrier and enters the cerebral tissue. In recent studies, Mino has been introduced as an antioxidant and anti-apoptotic chemical compound, and therefore, it was examined as a protective candidate against Cd-induced neurotoxicity. In this study, PC12 cells were exposed to Cd alone, or after being pre-treated with Mino. Initially, the cell viability and oxidative stress were analyzed using the MTT assay and fluorimetry, respectively. Then, Cd-induced apoptosis and Mino anti-apoptotic effect were evaluated in both intrinsic and extrinsic pathways using western blot analysis. Exposing PC12 cells to Cd for 24 h decreased cell viability and increased production of reactive oxygen species in comparison with the control group. Cd (35 μM) also elevated the level of caspase-8, Bax/Bcl-2, and caspase-3 proteins in the cells. Mino pre-treatment for 2 h (100 nM) increased the number of viable cells and decreased the production of reactive oxygen species, and the level of all apoptotic markers in comparison to Cd-treated cells. Considering all the evidence, it appears that Mino holds promising antioxidant and anti-apoptotic activity and can protect cells against Cd-induced oxidative stress and prevent apoptotic cell death.

Cadmium induces mitochondrial dysfunction via SIRT1 suppression-mediated oxidative stress in neuronal cells

Cadmium is a widespread environmental contaminant and its neurotoxicity has raised serious concerns. Mitochondrial dysfunction is a key event in Cd-induced nervous system disease; however, the exact molecular mechanism involved has not been fully elucidated. Increasing evidences have shown that Sirtuin 1 (SIRT1) is the key target protein impaired in Cd-induced mitochondrial dysfunction. In this study, the role of SIRT1 in Cd-induced mitochondrial dysfunction and cell death and the underlying mechanisms were evaluated in vitro using PC12 cells and primary rat cerebral cortical neurons. The results showed that Cd exposure caused cell death by inhibiting SIRT1 expression, thus inducing oxidative stress and mitochondrial dysfunction in vitro. However, inhibition of oxidative stress by the antioxidant puerarin alleviated Cd-induced mitochondrial dysfunction. Furthermore, activation of SIRT1 using the agonist Srt1720 significantly abolished Cd-induced oxidative stress and mitochondrial dysfunction and ultimately alleviated Cd-induced neuronal cell death. Collectively, our data indicate that Cd induced mitochondrial dysfunction via SIRT1 suppression-mediated oxidative stress, leading to the death of PC12 cells and primary rat cerebral cortical neurons. These findings suggest a novel mechanism for Cd-induced neurotoxicity.

Pancreas-Liver-Adipose Axis: Target of Environmental Cadmium Exposure Linked to Metabolic Diseases

Cadmium has been well recognized as a critical toxic agent in acute and chronic poisoning cases in occupational and nonoccupational settings and environmental exposure situations. Cadmium is released into the environment after natural and anthropogenic activities, particularly in contaminated and industrial areas, causing food pollution. In the body, cadmium has no biological activity, but it accumulates primarily in the liver and kidney, which are considered the main targets of its toxicity, through oxidative stress and inflammation. However, in the last few years, this metal has been linked to metabolic diseases. The pancreas-liver-adipose axis is largely affected by cadmium accumulation. Therefore, this review aims to collect bibliographic information that establishes the basis for understanding the molecular and cellular mechanisms linked to cadmium with carbohydrate, lipids, and endocrine impairments that contribute to developing insulin resistance, metabolic syndrome, prediabetes, and diabetes.

Melatonin protects against cadmium-induced oxidative stress via mitochondrial STAT3 signaling in human prostate stromal cells

Melatonin protects against Cadmium (Cd)-induced toxicity, a ubiquitous environmental toxicant that causes adverse health effects by increasing reactive oxygen species (ROS) production and mitochondrial dysfunction. However, the underlying mechanism remains unclear. Here, we demonstrate that Cd exposure reduces the levels of mitochondrially-localized signal transducer and activator of transcription 3 (mitoSTAT3) using human prostate stromal cells and mouse embryonic fibroblasts. Melatonin enhances mitoSTAT3 abundance following Cd exposure, which is required to attenuate ROS damage, mitochondrial dysfunction, and cell death caused by Cd exposure. Moreover, melatonin increases mitochondrial levels of GRIM-19, an electron transport chain component that mediates STAT3 import into mitochondria, which are downregulated by Cd. In vivo, melatonin reverses the reduced size of mouse prostate tissue and levels of mitoSTAT3 and GRIM-19 induced by Cd exposure. Together, these data suggest that melatonin regulates mitoSTAT3 function to prevent Cd-induced cytotoxicity and could preserve mitochondrial function during Cd-induced stress.

Integrated transcriptome and proteome unveiled distinct toxicological effects of long-term cadmium pollution on the silk glands of Pardosa pseudoannulata

Cadmium (Cd) induces severe soil pollution worldwide and exerts adverse effects on paddy field arthropods. Spiders grant a novel perspective to assess the Cd-induced toxicity, yet the impacts of long-term Cd stress on spider silk glands and its underlying mechanism remain elusive. The study showed that Cd stress enervated the antioxidant system in the spider Pardosa pseudoannulata, manifested as the decreases of glutathione peroxidase and peroxidase, and the increase of malonaldehyde (p < 0.05). In addition, a total of 1459 differentially expressed genes (DEGs) and 404 differentially expressed proteins (DEPs) were obtained from the silk glands' transcriptome and proteome. DEGs and DEPs encoding spidroin (e.g., tubuliform spidroin and ampullate spidroin) and amino acids metabolism (e.g., alanine, proline, and glycine) were distinctively down-regulated. Further enrichment analysis verified that Cd stress could inhibit amino acid metabolism via the down-regulation of several key enzymes, including glutathione synthase, methylthioadenosine phosphorylase, S-adenosylmethionine synthetase, etc. In addition, the hedgehog signaling pathway regulating cellular growth and development was down-regulated under Cd stress. A protein-protein interaction network showed that long-term Cd stress could inhibit some key biological processes in the silk glands, including peptide biosynthetic process and cytoskeleton part. Collectively, this comprehensive study established an effective animal detection model for evaluating Cd-induced toxicity, presented key biomarkers for further validation, and provided novel insights to investigate the molecular mechanisms of spiders to Cd pollution.

Elucidations of Molecular Mechanism and Mechanistic Effects of Environmental Toxicants in Neurological Disorders

Due to rising environmental and global public health concerns associated with environmental contamination, human populations are continually being exposed to environmental toxicants, including physical chemical mutagens widespread in our environment causing adverse consequences and inducing a variety of neurological disorders in humans. Physical mutagens comprise ionizing and non-ionizing radiation, such as UV rays, IR rays, X-rays, which produces a broad spectrum of neuronal destruction, including neuroinflammation, genetic instability, enhanced oxidative stress driving mitochondrial damage in the human neuronal antecedent cells, cognitive impairment due to alterations in neuronal function, especially in synaptic plasticity, neurogenesis repression, modifications in mature neuronal networks drives to enhanced neurodegenerative risk. Chemical Mutagens including alkylating agents (EMS, NM, MMS, and NTG), Hydroxylamine, nitrous acid, sodium azide, halouracils are the major toxic mutagen in our environment and have been associated with neurological disorders. These chemical mutagens create dimers of pyrimidine that cause DNA damage that leads to ROS generation producing mutations, chromosomal abnormalities, genotoxicity which leads to increased neurodegenerative risk. The toxicity of four heavy metal including Cd, As, Pb, Hg is mostly responsible for complicated neurological disorders in humans. Cadmium exposure can enhance the permeability of the BBB and penetrate the brain, driving brain intracellular accumulation, cellular dysfunction, and cerebral edema. Arsenic exerts its toxic effect by induction of ROS production in neuronal cells. In this review, we summarize the molecular mechanism and mechanistic effects of mutagens in the environment and their role in multiple neurological disorders.

Puerarin alleviates cadmium-induced rat neurocyte injury by alleviating Nrf2-mediated oxidative stress and inhibiting mitochondrial unfolded protein response

Cadmium (Cd) is a highly neurotoxic environmental pollutant. Puerarin (Pur) is a natural antioxidant isolated from Kudzu root that exhibits a powerful neuroprotective effect. Herein, we illustrated the mechanism underlying the protective effect of Pur on Cd-induced rat neurocyte injury in an in vivo rat model as well as in vitro using PC12 cells and primary rat cerebral cortical neurons. First, the results showed that Pur alleviated Cd-induced cerebral cortical pathological damage and decreased the viability of neurocytes. Furthermore, Cd activated the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, which plays a negative role in Cd-induced rat neurocyte injury. In addition, Pur alleviated Cd-induced oxidative stress by enhancing antioxidant defense, reducing reactive oxygen species (ROS) accumulation and lipid peroxidation, and inhibiting activation of the Nrf2 signaling pathway in rat neurocytes. Moreover, Pur inhibited the Cd-induced mitochondrial unfolded protein response (UPRmt) in rat neurocytes. Overall, Pur alleviated Cd-induced rat neurocyte injury by alleviating Nrf2-mediated oxidative stress and inhibiting UPRmt.

The Effect of Oxidative Stress-Induced Autophagy by Cadmium Exposure in Kidney, Liver, and Bone Damage, and Neurotoxicity

Environmental and occupational exposure to cadmium has been shown to induce kidney damage, liver injury, neurodegenerative disease, and osteoporosis. However, the mechanism by which cadmium induces autophagy in these diseases remains unclear. Studies have shown that cadmium is an effective inducer of oxidative stress, DNA damage, ER stress, and autophagy, which are thought to be adaptive stress responses that allow cells exposed to cadmium to survive in an adverse environment. However, excessive stress will cause tissue damage by inducing apoptosis, pyroptosis, and ferroptosis. Evidently, oxidative stress-induced autophagy plays different roles in low- or high-dose cadmium exposure-induced cell damage, either causing apoptosis, pyroptosis, and ferroptosis or inducing cell survival. Meanwhile, different cell types have different sensitivities to cadmium, which ultimately determines the fate of the cell. In this review, we provided a detailed survey of the current literature on autophagy in cadmium-induced tissue damage. A better understanding of the complex regulation of cell death by autophagy might contribute to the development of novel preventive and therapeutic strategies to treat acute and chronic cadmium toxicity.

The effect of Ulva rigida (C. Agardh, 1823) against cadmium-induced apoptosis and oxidative stress

Cadmium (Cd) is known as a pollutant source in recent years with the increase in industrialization. Algae have secondary metabolites with high biological activity, used for pharmaceutical agents. The liver and kidney are the primary organs involved in the elimination of systemic cadmium and the main targets of cadmium toxicity. In the previous research, it was determined the ameliorative effects of the extract obtained from Ulva rigida in the liver tissue of rats induced by cadmium. 35 female Wistar rats between 225-240 g were used. The subjects were injected subcutaneously with 1 mg/kg cadmium chloride (CdCl2) four times a week for four weeks. The study was carried out by groups as control (G1), Cadmium group (1 mg/kg CdCl2-G2), Algae group (100 mg/kg-G3), Cd+algae group (1 mg/kg CdCl2+50 mg/kg algae extract-G4) and Cd+algae group (1 mg/kg CdCl2+100 mg/kg algae extract -G5). The subjects were sacrificed by cervical dislocation. Liver tissue and cardiac blood were collected. It was determined that oxidative stress with iNOS, inflammation and apoptosis with TNF-α increased with cadmium induction, while there was a statistically significant decrease in the groups that were given algae extract. In addition, biochemical changes in SOD, CAT and MDA values were found to be significant (p<0.05). As a result, it was determined that algae extract could play a protective role with its antioxidant and antiapoptotic properties in experimentally induced cadmium toxicity in rats.

Wnt/β-Catenin Signaling Pathway Is Strongly Implicated in Cadmium-Induced Developmental Neurotoxicity and Neuroinflammation: Clues from Zebrafish Neurobehavior and In Vivo Neuroimaging

Cadmium (Cd) is a toxic heavy metal and worldwide environmental pollutant which seriously threatens human health and ecosystems. It is easy to be adsorbed and deposited in organisms, exerting adverse effects on various organs including the brain. In a very recent study, making full use of a zebrafish model in both high-throughput behavioral tracking and live neuroimaging, we explored the potential developmental neurotoxicity of Cd²⁺ at environmentally relevant levels and identified multiple connections between Cd²⁺ exposure and neurodevelopmental disorders as well as microglia-mediated neuroinflammation, whereas the underlying neurotoxic mechanisms remained unclear. The canonical Wnt/β-catenin signaling pathway plays crucial roles in many biological processes including neurodevelopment, cell survival, and cell cycle regulation, as well as microglial activation, thereby potentially presenting one of the key targets of Cd²⁺ neurotoxicity. Therefore, in this follow-up study, we investigated the implication of the Wnt/β-catenin signaling pathway in Cd²⁺-induced developmental disorders and neuroinflammation and revealed that environmental Cd²⁺ exposure significantly affected the expression of key factors in the zebrafish Wnt/β-catenin signaling pathway. In addition, pharmacological intervention of this pathway via TWS119, which can increase the protein level of β-catenin and act as a classical activator of the Wnt signaling pathway, could significantly repress the Cd²⁺-induced cell cycle arrest and apoptosis, thereby attenuating the inhibitory effects of Cd²⁺ on the early development, behavior, and activity, as well as neurodevelopment of zebrafish larvae to a certain degree. Furthermore, activation and proliferation of microglia, as well as the altered expression profiles of genes associated with neuroimmune homeostasis triggered by Cd²⁺ exposure could also be significantly alleviated by the activation of the Wnt/β-catenin signaling pathway. Thus, this study provided novel insights into the cellular and molecular mechanisms of Cd²⁺ toxicity on the vertebrate central nervous system (CNS), which might be helpful in developing pharmacotherapies to mitigate the neurological disorders resulting from exposure to Cd²⁺ and many other environmental heavy metals.

The role of inflammation in cadmium nephrotoxicity: NF-κB comes into view

Kidney diseases are major health problem and understanding the underlined mechanisms that lead to kidney diseases are critical research points with a marked potential impact on health. Cadmium (Cd) is a heavy metal that occurs naturally and can be found in contaminated food. Kidneys are the most susceptible organ to heavy metal intoxication as it is the main route of waste excretion. The harmful effects of Cd were previously well proved. Cd induces inflammatory responses, oxidative injury, mitochondrial dysfunction and disturbs Ca²⁺ homeostasis. The nuclear factor-kappa B (NF-κB) is a cellular transcription factor that regulates inflammation and controls the expression of many inflammatory cytokines. Therefore, great therapeutic benefits can be attained from NF-κB inhibition. In this review we focused on certain compounds including cytochalasin D, mangiferin, N-acetylcysteine, pyrrolidine dithiocarbamate, roflumilast, rosmarinic acid, sildenafil, sinapic acid, telmisartan and wogonin and certain plants as Astragalus Polysaccharide, Ginkgo Biloba and Thymus serrulatus that potently inhibit NF-κB and effectively counteracted Cd-associated renal intoxication. In conclusion, the proposed NF-κB involvement in Cd-renal intoxication clarified the underlined inflammation associated with Cd-nephropathy and the beneficial effects of NF-κB inhibitors that make them the potential to substantially optimize treatment protocols for Cd-renal intoxication.

Relationships between urinary metals concentrations and cognitive performance among U.S. older people in NHANES 2011-2014

Background

Epidemiological evidence on Urine metals and cognitive impairment in older individuals is sparse and limited. The goal of this study was to analyze if there was a link between urinary metal levels and cognitive performance in U.S. people aged 60 and up.

Methods

The National Health and Nutrition Examination Survey (NHANES) data from 2011 to 2014 were utilized in this cross-sectional analysis. Memory function was quantified using the following methods: Established Consortium for Word Learning in Alzheimer's Disease (CERAD-WL) (immediate learning and recall and delayed recall), Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST). An inductively coupled plasma mass spectrometry (ICP-MS) was used to estimate urine metal concentrations. The connection of Urine metals level with cognitive function was investigated employing binary logistic regression and restricted cubic spline models.

Results

A total of 840 participants aged 60 years and over were enrolled in this study. After controlling for confounders, the association between cadmium, barium, cobalt, cesium, manganese, and thallium and poor cognitive performance showed significance in multiple logistic regression compared to the lowest quartile of metals. In the DSST test, the weighted multivariate adjusted ORs (95% CI) for cadmium in the highest quartile, barium and cesium in the third quartile were 2.444 (1.310-4.560), 0.412 (0.180-0.942) and 0.440 (0.198-0.979), respectively. There were L-shaped associations between urine cesium, barium, or manganese and low cognitive performance in DSST. Urine lead, molybdenum and uranium did not show any significant relationships with cognitive impairment, respectively, compared to the respective lowest quartile concentrations.

Conclusion

The levels of barium (Ba), cobalt (Co), cesium (Cs), manganese (Mn), and thallium (Tl) in urine were found to be negatively related to the prevalence of impaired cognitive performance in our cross-sectional investigation. Higher cadmium (Cd) levels were associated with cognitive impairment.

Phytochemical: a treatment option for heavy metal induced neurotoxicity

Heavy metals are known to be carcinogenic, mutagenic, and teratogenic. Some heavy metals are necessary while present in the growing medium in moderate concentrations known to be essential heavy metals as they required for the body functioning as a nutrient. But there are some unwanted metals and are also toxic to the environment and create a harmful impact on the body, which termed to be non-essential heavy metals. Upon exposure, the heavy metals decrease the major antioxidants of cells and enzymes with the thiol group and affect cell division, proliferation, and apoptosis. It interacts with the DNA repair mechanism and initiates the production of reactive oxygen species (ROS). It subsequently binds to the mitochondria and may inhibit respiratory and oxidative phosphorylation in even low concentrations. This mechanism leads to damage antioxidant repair mechanism of neuronal cells and turns into neurotoxicity. Now, phytochemicals have led to good practices in the health system. Phytochemicals that are present in the fruits and herbs can preserve upon free radical damage. Thus, this review paper summarized various phytochemicals which can be utilized as a treatment option to reverse the effect of the toxicity caused by the ingestion of heavy metals in our body through various environmental or lifestyles ways.

Effect of zinc and copper ions on cadmium-induced toxicity in rat cultured cortical neurons

BACKGROUND

Cadmium is a highly toxic heavy metal that is capable of accumulating in the body and causing neurodegeneration. However, the effect of other trace elements on Cd²⁺ toxicity is currently poorly understood. The aim of this work was to study the effect of Zn²⁺ and Cu²⁺ ions on cadmium-induced death of neurons in the cerebral cortex.

METHODS

The work was performed on rat cortical primary cultures. The MTT test was used to determine the cytotoxicity effects. Analysis of intracellular Ca²⁺ concentration was assessed by the Fluo-4 AM calcium indicator that exhibit an increase in fluorescence upon binding Ca²⁺. MitoSOX Red (mitochondrial superoxide indicator) was used to measuring mitochondrial ROS content in live cells.

RESULTS

In this article, we show that the administration of CdCl₂ (0.005-0.02 mM) for 48 h induced an increase in dose-dependent death rate of cultured cortical neurons. Mature neurons were more sensitive to the damaging effects of Cd²⁺ than immature ones. ZnCl₂ (0.01-0.03 mM) significantly protected neurons from this toxic effect. In contrast to ZnCl₂, CuCl₂ (0.01 mM) increased cadmium neurotoxicity. Using Fluo-4 AM, measurements of intracellular calcium ions demonstrated that 24 h-exposure to Cd²⁺ induced intensive increase in Fluo-4 fluorescence in neurons, which was significantly reduced by zinc ions. CuCl₂ increased the cadmium-induced Fluo-4 and MitoSOX Red fluorescence in neurons. The chelator of intracellular Ca²⁺ BAPTA significantly decreased Cd²⁺-induced intensive increase in Fluo-4 fluorescence in cells.

CONCLUSION

The data obtained by us indicate that Zn²⁺ and Cu²⁺ can affect the neurotoxicity of cadmium in different directions: Zn²⁺ weaken the violation of intracellular calcium homeostasis caused by cadmium, preventing cell death, while Cu²⁺ potentiate the increase in the level of free intracellular calcium induced by cadmium and the development of mitochondrial dysfunction with an increase in the production of free radicals in differentiated cultured neurons of the cerebral cortex, which ultimately stimulates cytotoxicity.

Gallic and ascorbic acids supplementation alleviate cognitive deficits and neuropathological damage exerted by cadmium chloride in Wistar rats

Cadmium is a highly neurotoxic heavy metal that interferes with DNA repair mechanisms via generation of reactive oxygen species. The potentials of polyphenols and antioxidants as effective protective agents following heavy metal-induced neurotoxicity are emerging. We therefore explored the neuroprotective potentials of gallic and ascorbic acids in CdCl₂-induced neurotoxicity. Seventy-two Wistar rats were divided into six groups. Group A received distilled water, B: 3 mg/kg CdCl₂, C: 3 mg/kg CdCl₂ + 20 mg/kg gallic acid (GA), D: 3 mg/kg CdCl₂ + 10 mg/kg ascorbic acid (AA), E: 20 mg/kg GA and F: 10 mg/kg AA orally for 21 days. Depression, anxiety, locomotion, learning and memory were assessed using a battery of tests. Neuronal structure and myelin expression were assessed with histological staining and immunofluorescence. The Morris Water Maze test revealed significant increase in escape latency in CdCl₂ group relative to rats concurrently treated with GA or AA. Similarly, time spent in the target quadrant was reduced significantly in CdCl₂ group relative to other groups. Concomitant administration of gallic acid led to significant reduction in the durations of immobility and freezing that were elevated in CdCl₂ group during forced swim and open field tests respectively. Furthermore, GA and AA restored myelin integrity and neuronal loss observed in the CdCl₂ group. We conclude that gallic and ascorbic acids enhance learning and memory, decrease anxiety and depressive-like behavior in CdCl₂-induced neurotoxicity with accompanying myelin-protective ability.

Histological alterations and oxidative stress in adult zebrafish muscle after aluminium exposure

Aluminium (Al) is among the most abundant metals in nature, and its presence in the environment is further increasing by anthropogenic activities. In water bodies, the Al concentrations ranged between 0.001 and 50 mg/L, raising concerns about the health of aquatic organisms. For this reason, zebrafish was chosen as the model, since it is well suited for ecotoxicological studies. Adult specimens were exposed to 11 mg/L of Al for 10, 15 and 20 days to assess both the morphology and the oxidative state of muscle tissue. Considering the involvement of ROS, the activity of the main antioxidant enzymes, metallothioneins contents, but also oxidative damage and enzymes involved in energy consumption and neuromuscular transmission were assessed. Collected data showed an increase in the thickness of the endomysium and resorbed myofibrils in the organisms exposed to Al for 10 days, and an increase of myotomes' size in the organisms exposed to Al for 15 days. Moreover, the organisms exposed for less time to Al, it was evident an activation of anaerobic metabolism and the increased activity of antioxidant enzymes such as superoxide dismutase, glutathione peroxidase and glutathione S-transferases. However, these effects stabilized with increasing exposure time. In addition, only after 20 days of treatment did the oxidative damage to the proteins and the activity of acetylcholinesterase increase while the levels of metallothioneins and the lipid peroxidation were lower for all treated animals when compared to the control group. Overall, the biochemical and histological changes induced by aluminium exposure in the muscular tissue represent a relevant contribution to understanding the environmental risk due to the diffusion of this metal within the aquatic compartment.

Exogenous melatonin enhances soybean (Glycine max (L.) Merr.) seedling tolerance to saline-alkali stress by regulating antioxidant response and DNA damage repair

Saline-alkali (SA) stress induces excessive reactive oxygen species (ROS) accumulation in plant cells, resulting in oxidative damages of membranes, lipids, proteins, and nucleic acids. Melatonin has antioxidant protection effects in living organisms and thus has received a lot of attention. This study aimed to investigate the effect and regulating mechanism of melatonin treatment on soybean tolerance to SA stress. In this study, cultivars Heihe 49 (HH49, SA-tolerant) and Henong 95 (HN95, SA-sensitive) were pot-cultured in SA soil, then treated with MT (0-300 μM) at V1 stage. SA stress induced ROS accumulation and DNA damage in the seedling roots of both cultivars, causing G1/S arrest in HN95 and G2/M arrest in HH49. Melatonin treatment enhanced the activity of antioxidant enzymes in soybean seedling roots and reduced ROS accumulation. Additionally, melatonin treatment upregulated DNA damage repair genes, thus enhancing the reduction of DNA oxidative damage under SA stress. The effects of melatonin treatment were manifested as decreased RAPD polymorphism, 8-hydroxy-2'-deoxyguanine (8-OH-dG) level, and relative density of apurinic sites (AP-sites). Meanwhile, melatonin treatment partially alleviated the SA-induced G1/S arrest in HN95 and G2/M arrest in HH49, thus enhancing soybean seedling tolerance to SA stress.

Effect of cadmium administration on the antioxidant system and neuronal death in the hippocampus of rats

Cadmium (Cd) is a heavy metal classified as a carcinogen whose exposure could affect the function of the central nervous system. Studies suggest that Cd modifies neuronal morphology in the hippocampus and affects cognitive tasks. The oxidative stress pathway is proposed as a mechanism of toxicity. However, this mechanism is not precise yet. This study aimed to evaluate the effect of Cd administration on oxidative stress markers in the male rat's hippocampus. Male Wistar rats were divided into (1) control (drinking water) and (2) treatment with Cd (32.5 ppm of cadmium chloride (CdCl₂ ) in water). The Cd was administered for 2, 3, and 4 months. The results show that the oral administration of CdCl₂ increased the concentration of Cd in plasma and hippocampus, and this response is time-dependent on its administration. Likewise, it caused an increase in lipid peroxidation and nitrosative stress markers. Moreover, it increased reactive astrogliosis and antioxidant enzyme activity. Consequently, the progression of the oxidative response exacerbated neurodegeneration in hippocampal cells. Our results suggest that Cd exposure induces a severe oxidative response that contributes critically to hippocampal neurodegeneration. It is suggested that exposure to Cd increases the risk of developing neurological diseases, which contributes to a decrease in the quality of life of the human and the environment in which it lives.

Is Turkish coffee protects Drosophila melanogaster on cadmium acetate toxicity by promoting antioxidant enzymes?

With their increasing use in today's industry, heavy metals cause biochemical and biophysical changes by affecting the control and regulatory systems of living things. Cadmium (Cd), a heavy metal, spreads to the environment through both natural sources and industrial activities. It is taken into the organism through water, food, skin contact or smoke. Systems and organs of living things are directly or indirectly affected by Cd toxicity. Besides their recreational usage, herbal products such as coffee are preferred in alternative medicine because of their antioxidant, anti-inflammatory, anticancer and antidiabetic effects. Turkish coffee (TK) is a drink rich in flavorings, phenolic compounds and antioxidant compounds. The study evaluated the possible antioxidant role of TK against oxidative stress induced by Cadmium acetate (CdA) in the fat tissues of old-young female individuals of Drosophila melanogaster. The female flies were fed with either a standard diet, or CdA (10-30 mg), or TK (2%), or both (CdA + TK) for 3 and 10 days. Following the completion of the feeding period, the amounts of fatbody and oxidative stress markers (oxidative stress index, malondialdehyde), activities of antioxidant enzymes (Glutathione-S-transferase, Catalase, and Superoxide dismutase) and their levels were measured. Fat body lipid droplets were high in the individuals exposed to high concentrations of CdA. It was determined that lipid droplets decreased but did not significantly alter oxidative stress in the individuals treated with TK (p = 0.05). This article may be of help in terms of the use of TK compounds as antioxidants to evaluate their effects in preventing heavy metal accumulation and stress in the aging process.

Cadmium impairs zebrafish swim bladder development via ROS mediated inhibition of the Wnt / Hedgehog pathway

The posterior swim bladder is an important organ in teleost fishes, that primarily maintains buoyancy and motility for swimming and survival. In this study, we examined the molecular mechanisms of the toxicity of cadmium (Cd) on the early development of the swim bladder in zebrafish. Embryonic Cd exposure resulted in the non-inflation of the swim bladder when the ambient Cd concentration was greater than or equal to 0.25 mg/L. Cd disturbed surfactant lipid distribution and inhibited the formation of all three tissue layers in the swim bladder. Additionally, excessive Cd down-regulated Wnt (fzd3, nkd1, fzd7 and axin2) and Hedgehog (ihh, shh, ptc1 and ptc2) signaling pathways. Conversely, Wnt signaling activation partially neutralized Cd-induced swim bladder developmental defects. Moreover, ROS scavenger reduced Glutathione (GSH) effectively recovered Cd induced defects in swim bladder and Wnt/Hedgehog signaling. Taken together, our results first revealed that Cd caused swim bladder developmental defects via ROS-mediated inhibition of the Wnt and Hedgehog pathways. These results herein provide important data for future toxicological studies and risk assessments of Cd.

Zoledronic acid-induced oxidative damage and endoplasmic reticulum stress-mediated apoptosis in human embryonic kidney (HEK-293) cells

Zoledronic acid, a nitrogen-containing bisphosphonate drug, is used for the treatment of osteoporosis, Paget's disease of bone, and tumor-induced osteolysis. Zoledronic acid has also gained a place in cancer treatment due to its cytotoxic and antiproliferative effects in many cancer cells. Although zoledronic acid is considered safe, kidney damage is still one of the concerns in therapeutic doses. In the study, the aim was to assess the nephrotoxic profiles of zoledronic acid in the human embryonic kidney (HEK-293) cells. Cytotoxicity evaluation was performed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) and neutral red uptake tests, while oxidative stress was performed by reactive oxygen species (ROS) production via flow cytometry, and the incomprehensible evaluation of ROS-related genes by RT-PCR and apoptosis was performed with Annexin-PI analysis in flow cytometry. The obtained result showed that zoledronic acid inhibited cell viability (IC₅₀ values were determined as 273.16  by MTT) and cell proliferation in a concentration-dependent manner, induced ROS production, caused glutathione depletion, and increased oxidative stress index and endoplasmic reticulum (ER) stress, indicating severe cellular stress. The expression levels of oxidative damage (L-fabp, α-GST, Nrf2, and HMOX1), ER stress (CASP4, IRE1-α, GADD153, and GRP78), and apoptosis (Bcl-2, Bax, Cyt-c, p53, CASP9, CASP3, NF-κB, TNF-α, and JNK) related genes were altered as well as IRE1-α protein levels. Herein, we were the first to show that increased oxidative stress and ER stress resulting in apoptosis are the key molecular pathways in zoledronic acid-induced nephrotoxicity equivalent to clinically administered concentrations.

Potentilla anserine L. polysaccharide protects against cadmium-induced neurotoxicity

Cadmium is a toxic metal that can damage the brain and other organs. This study aimed to explore the protective effects of Potentilla anserine L. polysaccharide (PAP) against CdCl2-induced neurotoxicity in N2a and SH-SY5Y cells and in the cerebral cortex of BALB/c mice. In addition, we aimed to identify the potential mechanisms underlying these protective effects. Relative to CdCl2 treatment alone, pretreatment with PAP prevented the reduction in cell viability evoked by CdCl2, decreased rates of apoptosis, promoted calcium homeostasis, decreased ROS accumulation, increased mitochondrial membrane potential, inhibited cytochrome C and AIF release, and prevented the cleavage of caspase-3 and PARP. In addition, PAP significantly decreased the CdCl2-induced phosphorylation of CaMKII, Akt, and mTOR. In conclusion, PAP represents a potential therapeutic agent for the treatment of Cd-induced neurotoxicity, functioning in part via attenuating the activation of the mitochondrial apoptosis pathway and the Ca2+-CaMKII-dependent Akt/mTOR pathway.

Puerarin alleviates cadmium-induced mitochondrial mass decrease by inhibiting PINK1-Parkin and Nix-mediated mitophagy in rat cortical neurons

Cadmium (Cd) has well-known central nervous system toxicity, and mitochondria are direct targets of Cd-induced neuronal toxicity. However, how Cd induces mitochondrial mass decrease in terms of its neurotoxic effects remains unknown. Puerarin, an isoflavone extracted from kudzu root, can cross the blood-brain barrier and exert protective effects in nervous system disease. The purpose of the study was to determine the mechanism of Cd-induced mitochondrial mass decrease and the protective role of puerarin in rat cortical neurons. The results indicated that Cd induced mitochondrial mass decrease by activating mitophagy mediated by the PTEN-induced putative kinase protein 1 (PINK1)-E3 ubiquitin ligase (Parkin) and Nip3-like protein X (Nix) pathways in rat cortical neurons. Puerarin improved the Cd-induced decrease in mitochondrial membrane potential (MMP) in vitro, and blocked PINK1-Parkin and Nix-mediated mitophagy, inhibiting Cd-induced mitochondrial mass decrease in rat cortical neurons in vitro and in vivo. In summary, our data clearly indicated that puerarin protects rat cortical neurons against Cd-induced neurotoxicity by ameliorating mitochondrial damage, inhibiting mitophagy-mediated mitochondrial mass decrease. Puerarin appears to have great potential as a neuroprotective agent.

Low phosphate mitigates cadmium-induced oxidative stress in Saccharomyces cerevisiae by enhancing endogenous antioxidant defence system

Cadmium is a highly toxic heavy metal that causes many harmful effects on human health and ecosystems. Metal chelation-based techniques have become a common approach for the treatment of metal poisoning and also for the remediation of metal contamination. Phosphate, an essential nutrient required for key cellular functions, has been supposed to be effective in reducing cadmium bioavailability, possibly through its chelating potential. In this study, we explored the effects of phosphate on cadmium toxicity and cellular response to cadmium stress in the eukaryotic model Saccharomyces cerevisiae. Our results reveal that cadmium toxicity is unexpectedly enhanced during phosphate repletion and optimal phosphate levels for yeast growth under cadmium stress conditions decline with increasing cadmium concentrations. The profound cadmium toxicity during phosphate repletion is unlikely to result from either elevated cadmium accumulation or dysregulated homeostasis of essential metals, but rather due to increased production of intracellular reactive oxygen species. We show that, under phosphate-depleted conditions, the activities of antioxidant enzymes, especially Mn-superoxide dismutase and catalase, are significantly promoted through transcriptional upregulation. Our findings highlight the important role of cellular response to phosphate limitation in mitigating cadmium toxicity and endogenous oxidative stress through the enhancement of antioxidant enzyme activity.

Increased selenium concentration in the synthesis of CdSe magic-sized quantum dots affects how the brain responds to oxidative stress

CdSe magic-sized quantum dots (MSQDs) have been widely used as fluorescent probes in biological systems due to their excellent optical properties with a broader fluorescence spectrum and stable luminescence in biological media. However, they can be cytotoxic and alter the redox balance depending on the amounts of Cd²⁺ adsorbed on their surface. Thus, the present study aimed to evaluate whether increases in selenium concentration in the synthesis of CdSe-MSQDs decrease the oxidative stress caused by Cd²⁺ -based quantum dots. CdSe-MSQDs synthesized with different concentrations of selenium were investigated against oxidative stress in the brain of chicken embryos by examining total antioxidant capacity, lipid peroxidation, thiol, and glutathione contents, as well as the activities of glutathione peroxidase, superoxide dismutase (SOD), catalase (CAT), and glutathione reductase. In addition, the vascularization of the chorioallantoic membrane (CAM) analysis was performed. Higher selenium concentrations alter the surface defect levels (decrease free Cd²⁺ ) and controlled the oxidative effects of CdSe-MSQDs by reducing the lipid peroxidation, restoring the glutathione defense system and the antioxidant enzymes SOD and CAT, and maintaining the vascular density of the CAM. The current findings reinforce the study of the effects of the presence of Cd²⁺ ions on the surface of quantum dots, changing toxicity, and aiming interesting strategies of nanomaterials in biological systems.

Role of neurotoxicants in the pathogenesis of Alzheimer's disease: a mechanistic insight

Alzheimer's disease (AD) is the most conspicuous chronic neurodegenerative syndrome, which has become a significant challenge for the global healthcare system. Multiple studies have corroborated a clear association of neurotoxicants with AD pathogenicity, such as Amyloid beta (Aβ) proteins and neurofibrillary tangles (NFTs), signalling pathway modifications, cellular stress, cognitive dysfunctions, neuronal apoptosis, neuroinflammation, epigenetic modification, and so on. This review, therefore, aimed to address several essential mechanisms and signalling cascades, including Wnt (wingless and int.) signalling pathway, autophagy, mammalian target of rapamycin (mTOR), protein kinase C (PKC) signalling cascades, cellular redox status, energy metabolism, glutamatergic neurotransmissions, immune cell stimulations (e.g. microglia, astrocytes) as well as an amyloid precursor protein (APP), presenilin-1 (PSEN1), presenilin-2 (PSEN2) and other AD-related gene expressions that have been pretentious and modulated by the various neurotoxicants. This review concluded that neurotoxicants play a momentous role in developing AD through modulating various signalling cascades. Nevertheless, comprehension of this risk agent-induced neurotoxicity is far too little. More in-depth epidemiological and systematic investigations are needed to understand the potential mechanisms better to address these neurotoxicants and improve approaches to their risk exposure that aid in AD pathogenesis.Key messagesInevitable cascade mechanisms of how Alzheimer's Disease-related (AD-related) gene expressions are modulated by neurotoxicants have been discussed.Involvement of the neurotoxicants-induced pathways caused an extended risk of AD is explicited.Integration of cell culture, animals and population-based analysis on the clinical severity of AD is addressed.

The protective effects of chitosan oligosaccharide (COS) on cadmium-induced neurotoxicity in Wistar rats

The aim of the study was to investigate the influence of chitosan oligosaccharide (COS) on some antioxidant and cytokine levels in the rat hippocampus as well as synaptophysin (SYP) immunoreactivity in the cerebral cortex of the cadmium (Cd) exposed rats. Thirty-two male albino Wistar rats were divided randomly into four equal groups as control (C; n = 8), Cd (n = 8), COS (n = 8), and Cd + COS (CdCOS; n = 8). The rats in the Cd and CdCOS groups received Cd chloride (CdCl₂) (2 mg/kg/d) orally by gastric gavage three times a week for 4 weeks. Besides, COS (200 mg/kg/d) was administered to COS and CdCOS groups five times a week for 4 weeks. Then, they were decapitated and hippocampal/cerebral cortex tissue samples were taken for measurement of GSH levels, CAT and SOD activities, MDA values, TNF-α, IL-6, and IL-10 levels as well as SYP immunoreactivity. Although tissue GSH levels were determined the lowest in the Cd group, these values were attenuated with COS treatment in the CdCOS group (p < .01). In addition, TNF-α levels were alleviated by COS treatment in the CdCOS group when compared to Cd (p < .01). SYP-positive cells were investigated in the cerebral cortex and found mild in the CdCOS group. COS exhibits potential protective effects on Cd-induced neurotoxicity in rats.

Bioremediation of triphenyl phosphate by Pycnoporus sanguineus: Metabolic pathway, proteomic mechanism and biotoxicity assessment

So far, no information about the biodegradability of TPhP by white rot fungi has previously been made available, herein, Pycnoporus sanguineus was used as the representative to investigate the potential of white rot fungi in TPhP bioremediation. The results suggested that the biodegradation efficiency of 5 mg/L TPhP by P. sanguineus was 62.84% when pH was adjusted to 6 and initial glucose concentration was 5 g/L. Seven biodegradation products were identified, indicating that TPhP was biotransformed through oxidative cleavage, hydroxylation and methylation. The proteomic analysis revealed that cytochrome P450s, aromatic compound dioxygenase, oxidizing species-generating enzymes, methyltransferases and MFS general substrate transporters might occupy important roles in TPhP biotransformation. Carboxylesterase and glutathione S-transferase were induced to resist TPhP stress. The biotreatment by P. sanguineus contributed to a remarkable decrease of TPhP biotoxicity. Bioaugmentation with P. sanguineus could efficiently promote TPhP biodegradation in the water-sediment system due to the cooperation between P. sanguineus and some putative indigenous degraders, including Sphingobium, Burkholderia, Mycobacterium and Methylobacterium. Overall, this study provided the first insights into the degradation pathway, mechanism and security risk assessment of TPhP biodegradation by P. sanguineus and verified the feasibility of utilizing this fungus for TPhP bioremediation applications.

Metabolomic Alterations in the Digestive System of the Mantis Shrimp Oratosquilla oratoria Following Short-Term Exposure to Cadmium

Mantis shrimp Oratosquilla oratoria is an economically critical aquatic species along the coast of China but strongly accumulates marine pollutant cadmium (Cd) in its digestive system. It is necessary to characterize the toxicity of Cd in the digestive system of mantis shrimp. The metabolic process is an essential target of Cd toxicity response. In this work, we used ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-TOF-MS) for untargeted metabolomics to characterize the metabolic changes in the digestive system of O. oratoria, exposed to 0.05 mg/L for 96 h. The aim of this study was to further investigate the effect of O. oratoria on Cd response to toxicity and develop biomarkers. Metabolomics analysis showed the alteration of metabolism in the digestive system of mantis shrimp under Cd stress. A total of 91 metabolites were differentially expressed and their main functions were classified into amino acids, phospholipids, and fatty acid esters. The enrichment results of differential metabolite functional pathways showed that biological processes such as amino acid metabolism, transmembrane transport, energy metabolism, and signal transduction are significantly affected. Based on the above results, the Cd-induced oxidative stress and energy metabolism disorders were characterized by the differential expression of amino acids and ADP in mantis shrimp, while the interference of transmembrane transport and signal transduction was due to the differential expression of phospholipids. Overall, this work initially discussed the toxicological response of Cd stress to O. oratoria from the metabolic level and provided new insights into the mechanism.

Resolvin D1 protects against cadmium chloride-induced memory loss and hippocampal damage in rats: A comparison with docosahexaenoic acid

BACKGROUND

Intoxication with cadmium (Cd) ions leads to hippocampal damage and cognitive impairment. However, omega-3 polyunsaturated fatty acids (n-3 PUFAs) exert neuroprotective effects in different animal models of neurodegeneration.

PURPOSE

This study compared the neuroprotective effect of the n-3 PUFA, docosahexaenoic acid (DHA), and its downstream metabolite, resolvin D1 (RVD1), on hippocampal damage and memory deficits in cadmium chloride (CdCl₂)-treated rats.

RESEARCH DESIGN

Control or CdCl₂ (0.5 mg/kg)-treated rats were subdivided into three groups (n = 18/each) and treated for 6 weeks as follows: (1) fed control diet, (2) fed DHA-rich diets (0.7 g/100 g), or (3) treated with RVD1 (0.2 μg/kg, i.p).

RESULTS

Treatment with a DHA-rich diet or RVD1 significantly increased the levels of docosahexaenoic acid and RVD1, respectively, in the hippocampal of CdCl₂-treated rats without affecting the reduction in the expression of the 15-lipooxygenase-1 (ALOX15). These effects were associated with improvements in rats' memory function and hippocampal structure, as well as a redction in the hippocampal levels of reactive oxygen species (ROS), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), nuclear localization of the nuclear factor-kappa beta p65 (NF-κB p65), and expression of cleaved caspase-3. Concomitantly, hippocampi of both groups of rats showed significantly higher levels of Bcl-2, superoxide dismutase (SOD), and glutathione (GSH), as well as enhanced nuclear levels of the nuclear factor erythroid 2-related factor 2 (Nrf-2). The effects of RVD1 on all these markers in the CdCl₂-induced rats were more profound than those of DHA. Also, the increase in the nuclear protein levels of Nrf-2 and the decrease in the levels of Bax and nuclear protein levels of NF-κB p65 were only seen in the hippocampal of CdCl₂ + RVD1-treated rats.

CONCLUSION

RVD1 is more powerful than DHA in preventing CdCl₂-induced memory loss and hippocampal damage in rats.

Toxicological interaction between tobacco smoke toxicants cadmium and nicotine: An in-vitro investigation

Cigarettes and other tobacco products are used to obtain nicotine that is responsible for their stimulating effects. However, a lot of other organic and inorganic chemicals are also released along with nicotine. Cadmium (Cd) is one of the several heavy metals that are health hazards and is one of the inorganic elements released in tobacco smoke. The in-vitro investigation focused on exploring the effects of nicotine hydrogen tartrate (NHT) and cadmium (Cd) and their toxic interactions in the A549 cell line. In cell viability assay NHT exhibited its IC50 at 11.71 mM concentration, and the IC50 of Cd was found to be 83 µM after a 24 h exposure. Toxic effects of NHT (5 mM and 10 mM), Cd (50 µM and 100 µM), and their combination were also investigated by flowcytometry. The investigation included apoptotic and necrotic events, the effect on different cell cycle phases, and generation of reactive oxygen species by NHT, Cd, and their combination of different concentrations. Data reveal evident toxic effects of NHT, Cd, and NHT + Cd. It also indicates that the toxic interaction of NHT and Cd is not additive and appears to be minimal when compared with NHT or Cd exposures alone.