Cadmium promotes glycolysis upregulation and glutamine dependency in human neuronal cells

Associations between plasma metabolites and heavy metal exposure in residents of environmentally polluted areas

Heavy metals are commonly released into the environment through industrial processes such as mining and refining. The rapid industrialization that occurred in South Korea during the 1960s and 1970s contributed significantly to the economy of the country; however, the associated mining and refining led to considerable environmental pollution, and although mining is now in decline in South Korea, the detrimental effects on residents inhabiting the surrounding areas remain. The bioaccumulation of toxic heavy metals leads to metabolic alterations in human homeostasis, with disruptions in this balance leading to various health issues. This study used metabolomics to explore metabolomic alterations in the plasma samples of residents living in mining and refining areas. The results showed significant increases in metabolites involved in glycolysis and the surrounding metabolic pathways, such as glucose-6-phosphate, phosphoenolpyruvate, lactate, and inosine monophosphate, in those inhabiting polluted areas. An investigation of the associations between metabolites and blood clinical parameters through meet-in-the-middle analysis indicated that female residents were more affected by heavy metal exposure, resulting in more metabolomic alterations. For women, inhabiting the abandoned mine area, metabolites in the glycolysis and pentose phosphate pathways, such as ribose-5-phosphate and 3-phosphoglycerate, have shown a negative correlation with albumin and calcium. Finally, Mendelian randomization(MR) was used to determine the causal effects of these heavy metal exposure-related metabolites on heavy metal exposure-related clinical parameters. Metabolite biomarkers could provide insights into altered metabolic pathways related to exposure to toxic heavy metals and improve our understanding of the molecular mechanisms underlying the health effects of toxic heavy metal exposure.

Hepatocellular degeneration in mice co-exposed to in-utero aluminium and cadmium: Implication of a disordered antioxidant and energy homeostatic response in the liver

The current study comprised four groups of pregnant animals viz; Control (CTR) received 10 ml/kg of normal saline, Al:10 mg/kg of AlCl3, Cd: 1.5 mg/Kg of CdCl2 Al+Cd; 10 mg/kg of AlCl3 and 1.5 mg/Kg of CdCl2. Treatment was done from pregnancy days (PNT) 7-20. After delivery, male animals were weaned on PSD 21 and sacrificed on PSD 78. From the study significant increases on serum liver enzymes in the group exposed to Cd and that exposed to Al+Cd were observed. The study further showed altered serum and hepatic antioxidant balance for the Cd, Al and Al+Cd groups compared to control. Similarly, lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH) activities in the liver were elevated in Cd and Al+Cd groups while an altered liver histological feature in treated groups were also observed. it was concluded that in utero co-exposure to Al and Cd had the ability to alter hepatic functional indices.

Measurements of cadmium levels in relation to tobacco dependence and as a function of cytisine administration

Cigarette smoking delivers a number of heavy metals, including cadmium (Cd), into the body. Bioaccumulation may result in an increase in pathological consequences over time. The assessment of changes in serum Cd concentrations during the treatment of cigarette dependence with cytisine was performed for the first time. Parameters assessing smoking habits, strength of addiction, and effectiveness of therapy were analyzed. Cd was determined before, during, and after the end of treatment. The serum Cd levels were significantly higher in the smokers than in the nonsmokers. Significant differences in Cd concentrations between sampling times in smokers were observed. Individuals who stopped smoking had significantly lower Cd concentrations compared to baseline. A significant positive correlation between the serum Cd before treatment and smoking urges was also obtained. Additionally, salivary Cd determinations were performed before treatment to evaluate the use of this method to assess cigarette addiction. Our findings indicate that Cd can be used as a biomarker of smoking addiction, and provide an alternative assessment of tobacco smoke exposure to other methods. The results provide new knowledge related to Cd concentrations in human body fluids and may play a role in monitoring and assessing the efficacy of cytisine for smoking cessation.

Morphological and metabolic changes in microglia exposed to cadmium: Cues on neurotoxic mechanisms

Microglial cells play a key role in protecting the central nervous system from pathogens and toxic compounds and are involved in the pathogenesis of different neurodegenerative diseases. Cadmium is a widespread toxic heavy metal, released into the environment at a rate of 30,000 tons/year by anthropogenic activities; it is easily uptaken by the human body through diet and cigarette smoke, as well as by occupational exposure. Once inside the body, cadmium enters the cells and substitutes to zinc and other divalent cations altering many biological functions. Its extremely long half-life makes it a serious health threat. Recent data suggest a role for heavy metals in many neurodegenerative diseases; however, the role of cadmium is still to be elucidated. In this work we report the investigation of cadmium toxicity towards murine BV2 microglial cells, a widely used model for the study of neurodegeneration. Results show that increasing cadmium concentrations increase oxidative stress, a proposed mechanism of neurodegeneration, but also that BV2 cells can keep oxidative stress under control by increasing glutathione reduction. Moreover, cadmium induces alterations of cell morphology and metabolism leading to mitochondrial impairment, without switching the cells to Warburg effect. Finally cadmium induces the release of proinflammatory cytokines, but does not markedly switch BV2 cells to M1 phenotype.

Selenium alleviates cadmium-induced mitophagy through FUNDC1-mediated mitochondrial quality control pathway in the lungs of sheep

Cadmium (Cd) is a poisonous metal element that causes mitochondrial dysfunction. Selenium (Se) can reduce the damage of Cd to various organs of animals, but the protective mechanism of Se in Cd-induced lung injury has not been fully elucidated. For purpose of further illustrating the specific mechanism of Se alleviated Cd-triggered pulmonary toxicity, 48 sheep were divided into 4 groups, of which the sheep in the treatment group were taken 1 mg/kg body weight (BW) of Cd, 0.34 mg/kg BW of Se, and 0.34 mg Se + 1 mg/kg BW of Cd by intragastric administration for 50 d, respectively. The results indicated that Cd caused inflammatory cell infiltration and alveolar wall thickening, which facilitated mitochondrial vacuolation and formation of mitophagosomes in lung tissues. Simultaneously, Cd treatment impaired the antioxidant capacity of sheep lung tissue. Additionally, Cd treatment down-regulated the expression levels of mitochondrial biogenesis and mitochondrial fusion, but up-regulated the levels of mitochondrial fission and mitophagy mediated by FUNDC1. Moreover, the immunofluorescence co-localization puncta of LC3B/COX IV, LC3B/FUNDC1 were increased after Cd treatment. Nevertheless, co-treatment with Se improved effectively the above variation caused by Cd exposure. In summary, Se could mitigate Cd-generated mitophagy through FUNDC1-mediated mitochondrial quality control pathway in the lungs of sheep.

Informer-Based Safety Risk Prediction of Heavy Metals in Rice in China

Focused supervision and early warning of heavy metal (HM)-contaminated rice areas can effectively protect people's livelihood security and maintain social stability. To improve the accuracy of risk prediction, an Informer-based safety risk prediction model for HMs in rice is constructed in this paper. First, based on the national sampling data and residential consumption statistics of rice, we construct a dataset of evaluation indicators that can characterize the level of rice safety risk so as to form a safety risk space. Second, based on the K-medoids clustering algorithm, we classify the rice safety risk space into levels. Finally, we use the Informer neural network model to predict the safety risk indicators of rice in each province so as to predict the safety risk level. This study compares the prediction accuracy of a self-constructed dataset of rice safety risk assessment indicators. The experimental results show that the prediction precision of the method proposed in this paper reaches 99.17%, 91.77%, and 91.33% for low, medium, and high risk levels, respectively. The model provides technical support and a scientific basis for screening the time and area of HM contamination of rice, which needs focus.

Characterization of the p.L145F and p.S135N Mutations in SOD1: Impact on the Metabolism of Fibroblasts Derived from Amyotrophic Lateral Sclerosis Patients

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the loss of the upper and lower motor neurons (MNs). About 10% of patients have a family history (familial, fALS); however, most patients seem to develop the sporadic form of the disease (sALS). SOD1 (Cu/Zn superoxide dismutase-1) is the first studied gene among the ones related to ALS. Mutant SOD1 can adopt multiple misfolded conformation, lose the correct coordination of metal binding, decrease structural stability, and form aggregates. For all these reasons, it is complicated to characterize the conformational alterations of the ALS-associated mutant SOD1, and how they relate to toxicity. In this work, we performed a multilayered study on fibroblasts derived from two ALS patients, namely SOD1^L145F and SOD1^S135N, carrying the p.L145F and the p.S135N missense variants, respectively. The patients showed diverse symptoms and disease progression in accordance with our bioinformatic analysis, which predicted the different effects of the two mutations in terms of protein structure. Interestingly, both mutations had an effect on the fibroblast energy metabolisms. However, while the SOD1^L145F fibroblasts still relied more on oxidative phosphorylation, the SOD1^S135N fibroblasts showed a metabolic shift toward glycolysis. Our study suggests that SOD1 mutations might lead to alterations in the energy metabolism.

Cadmium exposure decreases fasting blood glucose levels and exacerbates type-2 diabetes in a mouse model

PURPOSE

Although the effects of cadmium (Cd) on the development of diabetes have been extensively investigated, the relationship between Cd exposure and the severity of established diabetes is unclear. Herein, we investigate the effects of long-term exposure to Cd in a streptozotocin-induced mouse model of type-2 diabetes mellitus (T2DM) and the underlying mechanism.

METHODS

C57BL/6 Mice were divided into the following four groups: (1) control group; (2) Cd-exposed group; (3) diabetic group; (4) Cd-exposed diabetic group. Cd exposure was established by the administration of 155 ppm CdCl₂ in drinking water. After 25 weeks of treatment, serum fasting glucose and insulin were measured. Meanwhile, the liver and pancreas specimens were sectioned and stained with Hematoxylin and eosin. Gluconeogenesis, glycolysis, lactate concentration, and fibrosis in liver were evaluated.

RESULTS

Clinical signs attributable to diabetes were more apparent in Cd-exposed diabetic mice, while no effects of Cd exposure were found on non-diabetic mice. Cd exposure significantly decreased fasting blood glucose (FBG) levels in diabetic group. We further demonstrated that the glycolysis related hepatic enzymes, pyruvate kinase M2 (PKM-2) and lactic dehydrogenase A (LDHA) were both increased, while the gluconeogenesis related hepatic enzymes, phosphoenolpyruvate-1 (PCK-1) and glucose-6-phosphatase (G6Pase) were both decreased in Cd exposed diabetic mice, indicating that Cd increased glycolysis and inhibited gluconeogenesis in diabetic model. Moreover, lactate accumulation was noted accompanied by the increased inflammation and fibrosis in the livers of diabetic mice following Cd exposure.

CONCLUSIONS

Cd exposure disturbed glucose metabolism and exacerbated diabetes, providing a biological relevance that DM patients are at greater risk when exposed to Cd.

Is Cadmium Toxicity Tissue-Specific? Toxicogenomics Studies Reveal Common and Specific Pathways in Pulmonary, Hepatic, and Neuronal Cell Models

Several harmful modifications in different tissues-organs, leading to relevant diseases (e.g., liver and lung diseases, neurodegeneration) are reported after exposure to cadmium (Cd), a wide environmental contaminant. This arises the question whether any common molecular signatures and/or Cd-induced modifications might represent the building block in initiating or contributing to address the cells towards different pathological conditions. To unravel possible mechanisms of Cd tissue-specificity, we have analyzed transcriptomics data from cell models representative of three major Cd targets: pulmonary (A549), hepatic (HepG2), and neuronal (SH-SY-5Y) cells. Further, we compared common features to identify any non-specific molecular signatures. The functional analysis of dysregulated genes (gene ontology and KEGG) shows GO terms related to metabolic processes significantly enriched only in HepG2 cells. GO terms in common in the three cell models are related to metal ions stress response and detoxification processes. Results from KEGG analysis show that only one specific pathway is dysregulated in a significant way in all cell models: the mineral absorption pathway. Our data clearly indicate how the molecular mimicry of Cd and its ability to cause a general metal ions dyshomeostasis represent the initial common feature leading to different molecular signatures and alterations, possibly responsible for different pathological conditions.