Metal-induced oxidative stress and signal transduction

Insights into the trypanothione system in antimony-resistant and sensitive Leishmania tropica clinical isolates

Pentavalent antimonials are the mainstay treatment against different clinical forms of leishmaniasis. The emergence of resistant isolates in endemic areas has led to treatment failure. Unraveling the underlying resistance mechanism would assist in improving the treatment strategies against resistant isolates. This study aimed to investigate the RNA expression level of glutathione synthetase (GS), Spermidine synthetase (SpS), trypanothione synthetase (TryS) genes involved in trypanothione synthesis, and thiol-dependent reductase (TDR) implicated in drug reduction, in antimony-sensitive and -resistant Leishmania tropica isolates. We investigated 11 antimony-resistant and 11 antimony-sensitive L. tropica clinical isolates from ACL patients. Drug sensitivity of amastigotes was determined in mouse macrophage cell line J774A.1. The RNA expression level in the promastigote forms was analyzed by quantitative real-time PCR. The results revealed a significant increase in the average expression of GS, SpS, and TrpS genes by 2.19, 1.56, and 2.33-fold in resistant isolates compared to sensitive ones. The average expression of TDR was 1.24-fold higher in resistant isolates, which was insignificant. The highest correlation coefficient between inhibitory concentration (IC50) values and gene expression belonged to the TryS, GS, SpS, and TDR genes. Moreover, the intracellular thiol content was increased 2.17-fold in resistant isolates compared to sensitive ones and positively correlated with IC50 values. Our findings suggest that overexpression of trypanothione biosynthesis genes and increased thiol content might play a key role in the antimony resistance of L. tropica clinical isolates. In addition, the diversity of gene expression in the trypanothione system and thiol content among L. tropica clinical isolates highlighted the phenotypic heterogeneity of antimony resistance among the parasite population.

In vitro assessment of cytotoxicity of spent fluid catalytic cracking refinery catalysts on cell lines and identification of critical toxic metals

The Purpose of the present study was to quantify the responses of ten cell lines (HeLa, HepG2, HEK293, MDA-MB-231, A498, A549, A357, 3 T3, BALB-C3 T3, and NIH-3 T3) to spent fluid catalytic cracking catalysts (SFCCCs) from different petroleum refineries, and relate these responses to metal concentrations of SFCCC leachates (SFCCCLs). Cytotoxicity of SFCCCs were significantly different depending on cell lines. A357 and 3 T3 cell were the most sensitive, and A498 and HeLa cells were the least sensitive. HEK293 cells showed the least fluctuation in toxic response to different SFCCCLs among all cells. Cytotoxic IC50 values of SFCCCs to 7 kinds of cells were the most correlated with vanadium (V) concentration in SFCCCLs. V is the most critical toxic factor of SFCCC. Glutathione synthesis was induced in HepG2 cells exposed to higher concentrations of SFCCCLs. SFCCCLs with low concentration of V can induce the decrease of GSH/GSSG ratio in HepG2 cells, suggesting that high concentration of V inhibits the detoxification of glutathione.

Long-term Cu exposure alters CYP450s activity and induces jejunum injury and apoptosis in broilers

Copper (Cu) is an essential trace element that plays a crucial role in numerous physiopathological processes related to human and animal health. In the poultry industry, Cu is used to promote growth as a feed supplement, but excessive use can lead to toxicity on animals. Cytochrome P450 enzymes (CYP450s) are a superfamily of proteins that require heme as a cofactor and are essential for the metabolism of xenobiotic compounds. The purpose of this study was to explore the influence of exposure to Cu on CYP450s activity and apoptosis in the jejunum of broilers. Hence, we first simulated the Cu exposure model by feeding chickens diets containing different amounts of Cu. In the present study, histopathological observations have revealed morphological damage to the jejunum. The expression levels of genes and proteins of intestinal barrier markers were prominently downregulated. While the mRNA expression level of the gene associated with CYP450s was significantly increased. Additionally, apoptosis-related genes and proteins (Bak1, Bax, Caspase-9, Caspase-3, and CytC) were also significantly augmented by excessive Cu, while simultaneously decreasing the expression of Bcl-2. It can be concluded that long-term Cu exposure affects CYP450s activity, disrupts intestinal barrier function, and causes apoptosis in broilers that ultimately leads to jejunum damage.

The effects of green and chemically-synthesized copper oxide nanoparticles on the production and gene expression of morphinan alkaloids in Oriental poppy

Oriental poppy (Papaver orientale L.) belonging to the Papaveraceae family, has the capacity to synthesize a wide range of benzylisoquinoline alkaloids (BIAs). This experiment was conducted to investigate the effects of green and chemical copper oxide nanoparticles (CuO NPs) elicitors on oxidative stress and the BIAs biosynthesis pathway in the cell suspension culture of P. orientale. This research shows that both green and chemical CuO NPs at concentrations of 20 mg/L and 40 mg/L, induce oxidative stress in the cell suspension of P. orientale by increasing the production of H2O2 and the activity of antioxidant enzymes. The comparison of treatments revealed that utilizing a lower concentration of CuO NPs (20 mg/L) and extending the duration of cell suspension incubation (up to 48 h) play a more influential role in inducing the expression of the BIAs biosynthesis pathway genes (PsWRKY, TYDC, SalSyn, SalR, SalAT, T6ODM, COR and CODM) and increasing the production of morphinan alkaloids (thebaine, codeine, and morphine). The overarching results indicate that the concentration of CuO NPs and the duration of cell treatment have a more significant impact than the nature of CuO NPs in inducing oxidative stress and stimulating the expression of the BIAs pathway genes.

Influence of global warming and industrialization on coral reefs: A 600-year record of elemental changes in the Eastern Red Sea

The Red Sea has been recognized as a coral reef refugia, but it is vulnerable to warming and pollution. Here we investigated the spatial and temporal trends of 15 element concentrations in 9 coral reef sediment cores (aged from the 1460s to the 1980s AD) to study the influence of global warming and industrialization on the Eastern Red Sea coral reefs. We found Na, Ca, Cr, Fe, Co, Ni, and Sr concentrations were higher in the northern Red Sea (i.e., Yanbu), whereas Mg, P, S, Mn, and Cd concentrations were higher in the southern Red Sea (i.e., Thuwal & Al Lith) reef sediments. In the central (i.e., Thuwal) to southern (i.e., Al Lith) Red Sea, the study revealed diverse temporal trends in element concentrations. However, both reef sedimentation rates (-36.4 % and -80.5 %, respectively) and elemental accumulation rates (-49.4 % for Cd to -12.2 % for Zn in Thuwal, and -86.2 % for Co to -61.4 % for Cu in Al Lith) exhibited a declining pattern over time, possibly attributed to warming-induced thermal bleaching. In the central to northern Red Sea (i.e., Yanbu), the severity of thermal bleaching is low, while the reef sedimentation rates (187 %), element concentrations (6.7 % for S to 764 % for Co; except Na, Mg, Ca, Sr, and Cd), and all elemental accumulation rates (190 % for Mg to 2697 % for Co) exponentially increased from the 1970s, probably due the rapid industrialization in Yanbu. Our study also observed increased trace metal concentrations (e.g., Cu, Zn, and Ni) in the Thuwal and Al Lith coral reefs with severe bleaching histories, consistent with previous reports that trace metals might result in decreased resistance of corals to thermal stress under warming scenarios. Our study points to the urgent need to reduce the local discharge of trace metal pollutants to protect this biodiversity hotspot.

Antimony resistance and gene expression in Leishmania: spotlight on molecular and proteomic aspects

Leishmaniasis is a vector-borne parasitic disease caused by Leishmania parasites with a spectrum of clinical manifestations, ranging from skin lesions to severe visceral complications. Treatment of this infection has been extremely challenging with the concurrent emergence of drug resistance. The differential gene expression and the discrepancies in protein functions contribute to the appearance of 2 distinct phenotypes: resistant and sensitive, but the current diagnostic tools fail to differentiate between them. The identification of gene expression patterns and molecular mechanisms coupled with antimony (Sb) resistance can be leveraged to prompt diagnosis and select the most effective treatment methods. The present study attempts to use comparative expression of Sb resistance-associated genes in resistant and sensitive Leishmania, to disclose their relative abundance in clinical or in vitro selected isolates to gain an understanding of the molecular mechanisms of Sb response/resistance. Data suggest that the analysis of resistance gene expression would verify the Sb resistance or susceptibility only to a certain extent; however, none of the individual expression patterns of the studied genes was diagnostic as a biomarker of Sb response of Leishmania. The findings highlighted will be useful in bridging the knowledge gap and discovering innovative diagnostic tools and novel therapeutic targets.

Assessment of heavy metal accumulation and health risk in three essential edible weeds grown on wastewater irrigated soil

The main problem facing Egypt recently is the shortage of available water resources. Therefore, farmers resort to use wastewater for irrigation. So, the present work aims to assess the impacts of wastewater irrigation on the productivity of three edible weeds (Cichorium endivia, Sonchus oleraceous and Beta vulgaris) and its effect on the nutritional value of plants and its risk on human health. This study will focus on Shibin Al Kanater region, and the physicochemical characteristics of drainage water, canal water, drainage water-irrigated soils and canal-irrigated soils were estimated. The vegetative and traits of edible weeds were determined including their photosynthetic pigments, organic and inorganic nutrients content, and heavy metals content. The health risk index (HRI) associated with consumption of polluted plants was created using the estimated exposure factor of a crop to the oral reference dosage of the toxic metal. The main results showed that biomass productivity of S. oleraceous, B. vulgaris and C. endivia increased due to drainage water irrigation with increasing percentage as 27.9, 19.6, and 19.1%, respectively. Irrigation with drainage water significantly increased the photosynthetic pigments of edible weeds. Irrigation with drainage water increased carbohydrate content, crude protein, total soluble sugar, and gross energy in all studied weeds. C. endivia, S. oleraceus and B. vulgaris plants irrigated with canal and drainage water could accumulate Fe, Zn, Cu, and Co in their roots. C. endivia, S. oleraceus and B. vulgaris plants irrigated with canal water indicated HRI more than the unit for Mn, Cu, Pb, and Cd. This research advises that regulation be put in place to prohibit irrigation using untreated drainage and to restrict the discharge of industrial, domestic, and agricultural wastewater into irrigation canals.

A review on the potential risks and mechanisms of heavy metal exposure to Chronic Obstructive Pulmonary Disease

Chronic Obstructive Pulmonary Disease (COPD) is a chronic disease that affects patients as well as the health and economic stability of society as a whole. At the same time, heavy metal pollution is widely recognized as having a possible impact on the environment and human health. Therefore, these diseases have become important global public health issues. In recent years, researchers have shown great interest in the potential association between heavy metal exposure and the development of COPD, and there has been a substantial increase in the number of related studies. However, we still face the challenge of developing a comprehensive and integrated understanding of this complex association. Therefore, this review aimed to evaluate the existing epidemiological studies to clarify the association between heavy metal exposure and COPD. In addition, we will discuss the biological mechanisms between the two to better understand the multiple molecular pathways and possible mechanisms of action involved, and provide additional insights for the subsequent identification of potential strategies to prevent and control the effects of heavy metal exposure on the development of COPD in individuals and populations.

Neutrophils and the Systemic Inflammatory Response Syndrome (SIRS)

We are not entirely able to understand, assess, and modulate the functioning of the immune system in clinical situations that lead to a systemic inflammatory response. In the search for diagnostic and treatment strategies (which are still far from perfect), it became very important to study the pathogenesis and participation of endogenous inflammation mediators. This study attempts to more precisely establish the role of neutrophils in individual phenomena occurring during an inflammatory and anti-inflammatory reaction, taking into account their cidal, immunoregulatory, and reparative abilities. Pro- and anticoagulatory properties of endothelium in systemic inflammatory response syndrome (SIRS) are emphasised, along with the resulting clinical implications (the application of immunotherapy using mesenchymal stem/stromal cells (MSCs) or IL-6 antagonists in sepsis and COVID-19 treatment, among others). Special attention is paid to reactive oxygen species (ROS), produced by neutrophils activated during "respiratory burst" in the course of SIRS; the protective and pathogenic role of these endogenous mediators is highlighted. Moreover, clinically useful biomarkers of SIRS (neutrophil extracellular traps, cell-free DNA, DAMP, TREMs, NGAL, miRNA, selected cytokines, ROS, and recognised markers of endothelial damage from the group of adhesins by means of immunohistochemical techniques) related to the neutrophils are presented, and their role in the diagnosing and forecasting of sepsis, burn disease, and COVID-19 is emphasised. Finally, examples of immunomodulation of sepsis and antioxidative thermal injury therapy are presented.

Oxidative Stress in Wistar Rats Under Acute Restraint Stress and Its Modulation by Antioxidants and Nitric Oxide Modulators

BACKGROUND

Several pathogenic conditions leading to morbidity, including cancer, aging, diabetes, reperfusion injury, cardiovascular disease, and neurological disorders, are known to be exacerbated by oxidative stress. Antioxidant therapy is effective in the treatment of such disorders and appears to be a potential therapeutic technique to reduce oxidative stress. The aim of our study is to investigate the antioxidant effects of L-ascorbic acid and nitric oxide (NO) modulators on rats suffering from oxidative stress induced by acute restraint stress (RSx1).

METHODOLOGY

In this in vivo study, Wistar rats were subjected to one hour of restraint stress on day 21 to induce oxidative stress. Superoxide dismutase (SOD), total antioxidant capacity (TAC), catalase, glutathione (GSH), and malondialdehyde (MDA) were used to assess the antioxidant effects. IBM Corp. Released 2013. IBM SPSS Statistics for Windows, Version 22.0. Armonk, NY: IBM Corp. was used for data analysis.

RESULTS

Compared to vehicle groups, acute restraint stress (RSx1) dramatically increased MDA levels while decreasing GSH, SOD, total antioxidant capacity, and catalase. L-NAME, 7-NI, AG (50 mg/kg each), and L-ascorbic acid (200 mg/kg) reversed the changes in SOD, MDA, GSH, total antioxidant capacity, and catalase levels. The NO precursor L-arginine (1000 mg/kg) and NO synthase inhibitors followed the same trend.

CONCLUSION

Our study findings highlight the complex role of antioxidants and NO modulators in the pathogenesis of diseases, as evidenced by the reversal of oxidative stress indicators. Antioxidant therapy, with its potential to mitigate oxidative stress, emerges as a viable treatment option for a range of pathological conditions associated with oxidative stress.

The role of iron in the pathogenesis of endometriosis: a systematic review

STUDY QUESTION

What is the role of iron in the pathophysiology of endometriosis?

SUMMARY ANSWER

Iron excess is demonstrated wherever endometriotic tissues are found and is associated with oxidative stress, an inflammatory micro-environment, and cell damage; the iron-mediated oxidative stress is independently linked to subfertility, symptom severity, and malignant transformation.

WHAT IS KNOWN ALREADY

Iron is found in excess in endometriotic tissues, and multiple mechanisms have been studied and posited to explain this. It is clear that iron excess plays a vital role in promoting oxidative stress and cell damage. The evidence base is large, but no comprehensive reviews exist to summarize our understanding and highlight the overarching themes to further our understanding and suggest future directions of study for the field.

STUDY DESIGN SIZE DURATION

This systematic review with a thematic analysis retrieved studies from the PubMed, Embase, Web of Science, and Cochrane Library databases and searches were conducted from inception through to August 2022. Human and animal studies published in the English language were included and identified using a combination of exploded MeSH terms ('Iron' and 'Endometriosis') and free-text search terms ('Iron', 'Ferric', 'Ferrous', 'Endometriosis', 'Endometrioma').

PARTICIPANTS/MATERIALS SETTING METHODS

This review was reported in accordance with the PRISMA guidelines. All studies reporting original data concerning the role of iron or iron complexes in the pathophysiology of endometriosis were included. Studies that did not report original data or provided a review of the field were excluded. Bias analysis was completed for each included study by using the Newcastle-Ottawa scoring system.

MAIN RESULTS AND THE ROLE OF CHANCE

There were 776 records identified and these were screened down to 53 studies which met the eligibility criteria, including 6 animal and 47 human studies, with 3556 individual participants. Iron excess is demonstrated in various tissues and fluids, including ovarian endometriomas, ovarian follicles, ectopic endometriotic lesions, and peritoneal fluid. Markers of oxidative stress are strongly associated with high iron levels, and aberrant expression of iron-transport proteins has been demonstrated. Abnormal resistance to ferroptosis is likely. Iron-mediated oxidative stress is responsible for a pro-inflammatory micro-environment and is linked to subfertility, symptom severity, and, possibly, malignant transformation.

LIMITATIONS REASONS FOR CAUTION

A minority of the included studies were of objectively low quality with a high risk of bias and may lead to misleading conclusions. Additionally, multiple studies failed to appropriately characterize the included patients by known confounding variables, such as menstrual cycle phase, which may introduce bias to the findings.

WIDER IMPLICATIONS OF THE FINDINGS

Current literature depicts a central role of aberrant iron mechanics and subsequent oxidative stress in endometriosis. It is likely that iron excess is at least partly responsible for the persistence and proliferation of ectopic endometriotic lesions. As such, iron mechanics represent an attractive target for novel therapeutics, including iron chelators or effectors of the iron-oxidative stress pathway. There are significant gaps in our current understanding, and this review highlights and recommends several topics for further research. These include the role of iron chelation, resistance to ferroptosis, the relationship between iron excess and localized hypoxia, systemic iron pathophysiology in endometriosis, and the role of oxidative stress in malignant transformation.

STUDY FUNDING/COMPETING INTERESTS

J.W. and S.G.P. are supported by clinical fellowships at Liverpool University Hospital NHS Foundation trust. No additional funding was requested or required for the completion of this work. C.J.H. is supported by a Wellbeing of Women project grant (RG2137). D.K.H. is supported by a Wellbeing of Women project grant (RG2137) and an MRC clinical research training fellowship (MR/V007238/1). The authors have no conflicts of interest to declare.

REGISTRATION NUMBER

A protocol was prospectively registered with the PROSPERO database in August 2021 (CRD42021272818).

Toxicogenomic analysis of physiologically important metals: An integrated in silico approach

Biologically important metals regulate cellular homeostasis in living systems. Anthropogenic exposure to these metals can cause adverse effects, including an increased incidence of diseases in humans such as cancer, lung, and cardiovascular defects. However, the effects of metals and the common genes/signaling pathways involved in metal toxicity have not been elucidated. Hence, the present study used toxicogenomic data mining with the comparative toxicogenomics database to explore the impact of these metals. The metals were categorized into transition, alkali, and alkali earth. The common genes were identified and subjected to functional enrichment analysis. Further, gene-gene and protein-protein interactions were assessed. Also, the top ten transcription factors and miRNAs that regulate the genes were identified. The phenotypes and diseases that have increased incidence upon alterations of these genes were detected. Overall, we were able to identify IL1B and SOD2 as the common genes, along with the AGE-RAGE signaling pathway in diabetic complications as the common pathway altered. Enriched genes and pathways specific to each metal category were also found. Further, we identified heart failure as the major diseases that have increased the incidence of these metals' exposure. In conclusion, exposure to essential metals might cause adverse effects via inflammation and oxidative stress.

Hemocytes in blue mussel Mytilus edulis adopt different energy supply modes to cope with different BDE-47 exposures

The energetic response of blue mussel Mytilus edulis when coping with tetrabromodiphenyl ether (BDE-47) exposure was evaluated from the perspective of alterations in energy supply mode, and the possible regulating mechanism was discussed based on a 21-day bioassay. The results showed that the energy supply mode changed with concentration: 0.1 μg/L BDE-47 decreased the activity of isocitrate dehydrogenase (IDH), succinate dehydrogenase (SDH), malate dehydrogenase and oxidative phosphorylation, suggesting inhibition of the tricarboxylic (TCA) acid cycle and aerobic respiration. The coincident increase in phosphofructokinase and the decrease in lactate dehydrogenase (LDH) indicated that glycolysis and anaerobic respiration were increased. When exposed to 1.0 μg/L BDE-47, M. edulis mainly utilized aerobic respiration, but lowered glucose metabolism as indicated by the decrease in glutamine and l-leucine was suggested to be involved in this process, which was differed from that in the control. The reoccurrence of IDH and SDH inhibition as well as LDH elevation indicated attenuation of aerobic and anaerobic respiration when the concentration increased to 10 μg/L, but severe protein damage was evidenced based on the elevation of amino acids and glutamine. Under the 0.1 μg/L BDE-47, activation of the AMPK-Hif-1a signaling pathway promoted the expression of glut1, which was the potential mechanism for the improvement of anaerobic respiration, and further activated glycolysis and anaerobic respiration. This study shows that the energy supply mode experienced a conversion from aerobic respiration under normal conditions to anaerobic mode in the low BDE-47 treatment and back to aerobic respiration with increasing BDE-47 concentrations, which may represent a potential mechanism for mussel physiological responses when faced with different levels of BDE-47 stress.

Role of the tyrosine aminotransferase AccTATN gene in the response to pesticide and heavy metal stress in Apis cerana cerana

Tyrosine aminotransferase (TATN) is the first enzyme involved in the metabolic degradation of tyrosine, and it plays an important role in tyrosine detoxification and helps the body resist oxidative damage. However, the function of TATN in Apis cerana cerana (A. c. cerana) remains unclear. To explore the role of TATN in the response to pesticide and heavy metal stress in A. c. cerana, AccTATN was isolated and identified. AccTATN was highly expressed in the integument and the adult stage. Exposure to multiple pesticides and heavy metal stress upregulated AccTATN expression. RNA interference experiments showed that silencing AccTATN reduced the resistance of A. c. cerana to glyphosate and avermectins stress. The expression of antioxidant-related genes and the activity of antioxidant enzymes were reduced after AccTATN was silenced, leading to the accumulation of oxidative damage. Overexpression of the recombinant AccTATN protein in a prokaryotic system also confirmed its role in heavy metal stress and improved antioxidant capacity. Our study showed that AccTATN may promote resistance to pesticide and heavy metal stress by regulating the antioxidant capacity of A. c. cerana. This study provides a valuable theoretical basis for A. c. cerana conservation.

Insights into the antioxidative mechanisms of melatonin in ameliorating chromium-induced oxidative stress-mediated hepatic and renal tissue injuries in male Wistar rats

Chromium (Cr), a hazardous heavy metal, is toxic to human health and the environment. Severe detrimental effects of Cr on different physiological systems involve oxidative stress. In the current study, sodium dichromate di-hydrate was subcutaneously injected to male Wistar rats at a dose of 5 mg/kg b.w. and experimented up to 14 days to induce alterations in hepatic and renal tissues. Another group of rats was pre-treated with melatonin at three different doses (5, 10, and 20 mg/kg b.w.; orally) and 20 mg/kg b.w. dose was evidenced to provide maximal protection against Cr-induced alterations. The study demonstrated that melatonin efficiently preserved body weight, organ weight, intracellular antioxidant enzymes, and tissue morphology. Furthermore, melatonin was also found to protect organ damage markers, oxidative stress-biomarkers, activities of pro-oxidant enzymes, levels of reactive oxygen species (ROS), nitric oxide (NO), and collagen content through its antioxidative mechanisms. Moreover, melatonin effectively decreased tissue Cr content through its metal-chelating activity. Hence, the present study has established melatonin as a promising antioxidant for conserving the liver and kidney tissues from Cr-induced oxidative damage thereby strengthening the notion that this small indoleamine can act as a future therapeutic against Cr-induced oxidative stress-mediated tissue damage.

Telomeres susceptibility to environmental arsenic exposure: Shortening or lengthening?

Maintaining telomere length plays a crucial role in regulating cellular life span. Telomere lengthening or shortening is one of the important biomarkers which could predict the preceding or present diseases. Meanwhile, the impact of environmental arsenic exposure on telomere length has increasingly concerned. Although previous studies demonstrated the effects of arsenic on telomere length, the findings were unclear on whether telomere shortens or lengthens by arsenic exposure. Thus, this manuscript summarized and discussed the telomere length alteration following arsenic exposure and the possible does-response effect of arsenic on telomere length. The present review suggested that different age groups may respond differently to arsenic exposure, and the dose-response effect of arsenic could be a critical factor in its effect on telomere length. Moreover, speciation analysis of arsenic could be more informative in identifying the effect of arsenic on telomere length.

Gene expression analysis of antioxidant and DNA methylation on the rat liver after 4-week wood preservative chromated copper arsenate exposure

Our previous 4-week repeated dose toxicity study showed that wood preservative chromated copper arsenate (CCA) induced hepatocellular hypertrophy accompanied by biochemical hepatic dysfunction and an increase in oxidative stress marker, 8-hydroxydeoxyguanosine, in female rats. To further explore the molecular mechanisms of CCA hepatotoxicity, we analyzed 10%-buffered formalin-fixed liver samples from female rats for cell proliferation, apoptosis, and protein glutathionylation and conducted microarray analysis on frozen liver samples from female rats treated with 0 or 80 mg/kg/day of CCA. Chemical analysis revealed that dimethylated arsenical was the major metabolite in liver tissues of male and female rats. CCA increase labeling indices of proliferating cell nuclear antigen and decrease terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling accompanied with increased expression of protein glutathionylation, indicating a decrease in glutathione (GSH) in hepatocytes of female rats. Microarray analysis revealed that CCA altered gene expression of antioxidants, glutathione-S-transferase (GST), heat shock proteins and ubiquitin-proteasome pathway, cell proliferation, apoptosis, DNA methylation, cytochrome P450, and glucose and lipid metabolism in female rats. Increased expression of GSTs, including Gsta2, Gsta3, Mgst1, and Cdkn1b (p27), and decreased expression of the antioxidant Mt1, and DNA methylation Dnmt1, Dnmt3a, and Ctcf were confirmed in the liver of female rats in a dose-dependent manner. Methylation status of the promoter region of the Mt1 was not evidently changed between control and treatment groups. The results suggested that CCA decreased GSH and altered the expression of several genes, including antioxidants, GST, and DNA methylation, followed by impaired cell proliferation in the liver of female rats.

The Multiple Functions of Melatonin: Applications in the Military Setting

The aim of this review is to provide the reader with a general overview on the rationale for the use of melatonin by military personnel. This is a technique that is being increasingly employed to manage growing psycho-physical loads. In this context, melatonin, a pleotropic and regulatory molecule, has a potential preventive and therapeutic role in maintaining the operational efficiency of military personnel. In battlefield conditions in particular, the time to treatment after an injury is often a major issue since the injured may not have immediate access to medical care. Any drug that would help to stabilize a wounded individual, especially if it can be immediately administered (e.g., per os) and has a very high safety profile over a large range of doses (as melatonin does) would be an important asset to reduce morbidity and mortality. Melatonin may also play a role in the oscillatory synchronization of the neuro-cardio-respiratory systems and, through its epigenetic action, poses the possibility of restoring the main oscillatory waves of the cardiovascular system, such as the Mayer wave and RSA (respiratory sinus arrhythmia), which, in physiological conditions, result in the oscillation of the heartbeat in synchrony with the breath. In the future, this could be a very promising field of investigation.

Cadmium chloride generates cytotoxic reactive species that cause oxidative damage and morphological changes in human erythrocytes

Cadmium chloride (CdCl₂₎ is a widely used industrial compound that exhibits multiple organ toxicity. Cadmium is transported through blood where erythrocytes are exposed to its action. Here the effect of CdCl₂ on human erythrocytes was examined under in vitro conditions. Human erythrocytes were treated with 0.01-0.5 mM CdCl₂ for 24 h at 37 °C. Lysates were made from CdCl₂ treated and untreated (control) cells and used for further analysis. CdCl₂ treatment resulted in marked hemolysis of erythrocytes and oxidation of hemoglobin to methemoglobin. This will result in anemia and also reduce the oxygen carrying ability of erythrocytes. Hemoglobin oxidation was accompanied by degradation of heme and release of free ferrous iron moiety. Further analysis showed elevated lipid hydroperoxides and formation of advanced oxidation protein products along with reduction in total sulfhydryl content, indicating the generation of oxidative stress condition in the cell. Incubation of erythrocytes with CdCl₂ enhanced generation of reactive oxygen and nitrogen species, decreased the antioxidant power and inhibited pathways of glucose metabolism. Plasma membrane was damaged as indicated by enhanced osmotic fragility and inhibition of membrane bound enzymes. This was confirmed by electron microscopy which showed formation of echinocytes. These results show that CdCl₂ generates reactive species which impair the antioxidant system resulting in oxidative damage to erythrocytes.

Impact of Heavy Metal Toxicity on the Gut Microbiota and Its Relationship with Metabolites and Future Probiotics Strategy: a Review

The gut microbiota has a vital role in the maintenance of intestinal homeostasis. Several studies have revealed that environmental exposure to pollutants such as heavy metals may contribute to the progression of extensive list of diseases which may further lead to perturbations in the gut leading to dysbiosis. This manuscript critically reviews the alterations in the gut microbiota composition and function upon exposure to various toxic heavy metals prevalent in the environment. The disturbance in gut microbial ecology also affects the microbial metabolic profile which may alter the speciation state and bioavailability heavy metals thus affecting metal uptake-absorption/detoxification mechanisms associated to heavy metal metabolism. The toxic effects of various heavy metals either in single or in multimetallic combination and the gut microbiota associated host health and disease condition need a comprehensive assessment with important consideration for therapeutic and protective strategies against the damage to gut microbiota.

Genotoxic Biomonitoring in Children Living near the El Fraile Mine Tailings in Northern Guerrero State, Mexico

A genotoxic study was conducted with 101 elementary school children (56 girls and 45 boys) in the 6-7, 8-9, and 10-12 age ranges from El Fraile rural community, which is located beside the El Fraile mine tailings in Taxco of Alarcon City, in northern Guerrero State, Mexico. For this, we used the alkaline comet assay in exfoliated buccal mucosa cells, scoring three genotoxic parameters: tail intensity, tail moment, and tail length. Additionally, we detected oxidative DNA damage through urinary 8-OHdG levels by enzyme-linked immunosorbent assay. We also evaluated a control group consisting of 101 children in the same age ranges from Chilpancingo City, Guerrero, who had never lived near mining zones. Genotoxic results showed that there was a significant increase in three genotoxic parameters and urinary 8-OHdG levels in the exposed children group compared with the control group. Analysis of MANOVA revealed that boys aged 8 and 9 years had higher DNA damage than girls from the same exposure group, and Spearman's analysis identified a positive correlation between DNA damage and sex and age. This study provides the first valuable genotoxic data in children living in areas with environmental pollution.

The association of chemical composition particularly the heavy metals with the oxidative potential of ambient PM2.5 in a megacity (Guangzhou) of southern China

Atmospheric fine particulate matters (PM_2.5) can cause adverse health effects through the generation of reactive oxygen species (ROS), which is normally characterized by the oxidative potential (OP). However, the particulate components that are mainly responsible for the ROS-induced OP remain controversial and warrant further investigation, especially in megacities where high exposure exists and particulate composition is complex. In this study, we measured the OP of PM_2.5 using the dithiothreitol (DTT) assay with and without chelation of metals in a megacity in southern China, Guangzhou, in January and April. We explored the correlations between OP and various chemical components in PM_2.5, including water-soluble ions, organic carbon (OC), elemental carbon (EC), and metal elements. There are strong correlations between OP^DTTv (volume-normalized) and concentrations of PM_2.5, OC, and EC, while the correlations between OP^DTTm (mass-normalized) and mass-normalized water-soluble ions, OC, EC or metal elements are weak. The OP values with chelation were reduced by ∼90%, indicating that water-soluble heavy metals were the major contributors to OP of PM_2.5 in Guangzhou. On the other hand, correlations between OP^DTTm and OC improved significantly after the chelation of heavy metals, implying that OC explains the variance of OP^DTTm although its contribution to OP is much smaller than that of heavy metals. We postulate that there might be synergetic effects between water-soluble heavy metals (which contribute most to OP) and OC (which explains the variance of OP) in ROS generation by PM_2.5. The findings of the current study provide a better understanding on the critical components in PM_2.5 and potential synergism that might be responsible for health effects in urban areas.

Oxidative stress and antioxidant mechanisms of obligate anaerobes involved in biological waste treatment processes: A review

In-depth understanding of the molecular mechanisms and physiological consequences of oxidative stress is still limited for anaerobes. Anaerobic biotechnology has become widely accepted by the wastewater/sludge industry as a better alternative to more conventional but costly aerobic processes. However, the functional anaerobic microorganisms used in anaerobic biotechnology are frequently hampered by reactive oxygen/nitrogen species (ROS/RNS)-mediated oxidative stress caused by exposure to stressful factors (e.g., oxygen and heavy metals), which negatively impact treatment performance. Thus, identifying stressful factors and understanding antioxidative defense mechanisms of functional obligate anaerobes are crucial for the optimization of anaerobic bioprocesses. Herein, we present a comprehensive overview of oxidative stress and antioxidant mechanisms of obligate anaerobes involved in anaerobic bioprocesses; as examples, we focus on anaerobic ammonium oxidation bacteria and methanogenic archaea. We summarize the primary stress factors in anaerobic bioprocesses and the cellular antioxidant defense systems of functional anaerobes, a consortia of enzymatic and nonenzymatic mechanisms. The dual role of ROS/RNS in cellular processes is elaborated; at low concentrations, they have vital cell signaling functions, but at high concentrations, they cause oxidative damage. Finally, we highlight gaps in knowledge and future work to uncover antioxidant and damage repair mechanisms in obligate anaerobes. This review provides in-depth insights and guidance for future research on oxidative stress of obligate anaerobes to boost the accurate regulation of anaerobic bioprocesses in challenging and changing operating conditions.

Environmental and occupational exposure of metals and female reproductive health

Untainted environment promotes health, but the last few decades experienced steep upsurge in environmental contaminants posing detrimental physiological impact. The responsible factors mainly include the exponential growth of human population, havoc rise in industrialization, poorly planned urbanization, and slapdash environment management. Environmental degradation can increase the likelihood of human exposure to heavy metals, resulting in health consequences such as reproductive problems. As a result, research into metal-induced causes of reproductive impairment at the genetic, epigenetic, and biochemical levels must be strengthened further. These metals impact upon the female reproduction at all strata of its regulation and functions, be it development, maturation, or endocrine functions, and are linked to an increase in the causes of infertility in women. Chronic exposures to the heavy metals may lead to breast cancer, endometriosis, endometrial cancer, menstrual disorders, and spontaneous abortions, as well as pre-term deliveries, stillbirths. For example, endometriosis, endometrial cancer, and spontaneous abortions are all caused by the metalloestrogen cadmium (Cd); lead (Pb) levels over a certain threshold can cause spontaneous abortion and have a teratogenic impact; toxic amounts of mercury (Hg) have an influence on the menstrual cycle, which can lead to infertility. Impact of environmental exposure to heavy metals on female fertility is therefore a well-known fact. Thus, the underlying mechanisms must be explained and periodically updated, given the growing evidence on the influence of increasing environmental heavy metal load on female fertility. The purpose of this review is to give a concise overview of how heavy metal affects female reproductive health.

RETRACTED: Carveol ameliorates mercury-induced oxidative stress, neuroinflammation, and neurodegeneration in a mouse brain

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editors-in-Chief. Sections of panels from Figure 7B appear similar to each other. Also, inconsistencies have been noticed between the text of the subsection 2.5.4. ‘Morris Water Maze (MWM) test’ and Figure 6E. The journal records indicated that the names of the authors Sajid Rashid, Nadia Hussain, Mehreen Gul, Muhammad Ikram and Jingbo Li were added to the revised version of the article without exceptional approval by the handling Editor, which is contrary to the journal policy on changes to authorship.

Relationship between maternal heavy metal exposure and congenital heart defects: a systematic review and meta-analysis

Congenital heart defects (CHDs) are one of the major causes of death in infants and young children, and heavy metal exposure during pregnancy is one of the possible risk factors. However, the effect of heavy metal exposure on CHDs is still controversial. We searched English (PubMed, Web of Science) and Chinese (CNKI and WanFang database) databases for relevant articles. The summarized effect sizes and 95% confidence intervals (CIs) were calculated by pooling estimates using the random-effects model. Egger's test was used to estimate publication bias. Heterogeneity among studies was indicated by p-values and I². Finally, we conducted subgroup analyses to elucidate the causes of heterogeneity. Thirteen studies were included in this meta-analysis. A positive association between maternal exposure to heavy metals and CHDs was found. Pooling odds ratios (ORs) for arsenic, cadmium, mercury, and lead were 2.12, 1.30, 1.22, and 2.30, respectively for total CHDs. Regarding CHD subtypes, arsenic was associated with an increased risk of septal defects (OR: 1.82), barium with left ventricular outflow tract obstruction (LVOTO) (OR: 1.15) and septal defects (OR: 1.21), and lead with conotruncal defects (OR: 2.34) and LVOTO (OR: 1.93). A heterogeneous relationship was found between studies using different methods of measurement, which were mainly due to differences in actual exposure levels to heavy metals. This meta-analysis suggests significant associations between arsenic, cadmium, mercury, and lead exposure during pregnancy and an increased risk of specific CHDs in offspring. These findings underscore the importance of heavy metal exposure during pregnancy in the risk of CHDs in offspring.

The Associations between Metalloestrogens, GSTP1, and SLC11A2 Polymorphism and the Risk of Endometrial Cancer

Background: The incidence of endometrial cancer (EC) is still rising. Numerous risk factors including patient characteristics and molecular instability have been identified for EC. The presence of specific molecular markers allows specific diagnostic and prognostic approaches. Several single nucleotide polymorphisms (SNPs) have been identified to influence endometrial cancer risk. Metalloestrogens are metal ions which can mimic estrogen activity; however, their role in uterine pathologies remains unknown. This study aimed to investigate total blood trace elements levels and evaluate the distribution of selected genotypes in GSTP1 and SLC11A2 genes. Methods: This retrospective case-control analysis was carried out in peripheral blood samples of 110 women with endometrial cancer (EC; n = 21), uterine fibroma (n = 25), endometrial polyp (n = 48), and normal endometrium (n = 16). Analysis included measurement of metals and phosphor in serum, and of genetic polymorphisms in GST (rs1695) and SLC11A2 (rs224589) in DNA from white blood cells. Serum trace elements were measured using ICP-OES spectrometry. SNPs were identified using Taq Man real-time PCR genotyping assays. Results: The study confirmed higher age (OR 2.19, 95% CI 1.69–2.24), post-menopausal status (OR 1.89, 95% CI 1.36–1.94), and diabetes type 2 (OR 1.54; 95% CI 0.97–1.72) as independent risk factors for EC. We also found a high level of Cd (OR 1.49; 95% CI 1.31–1.63) and a low level of Co (OR 0.76; 95% CI 0.53–0.59) to be independent risk factors of EC. None of the tested polymorphisms of GSTP1 and SLC11A2 were associated with EC risk. However, high Cd (OR 1.21, 95% CI 1.15–1.29) and Ni (OR 1.07, 95% CI 1.05–1.18) serum levels were significantly associated with a SLC1A2 TG genotype, and high Cd levels with GSTP1 (OR 1.05, 95% CI 1.01–1.13).

Mercury-Induced Oxidative Stress Response in Benthic Foraminifera: An In Vivo Experiment on Amphistegina lessonii

The evaluation of the effects of pollution (e.g., Hg pollution) is a difficult task and relies mostly on biomonitoring based on bioindicators. The application of biomarkers may represent a complementary or alternative approach in environmental biomonitoring. Mercury is known to pose a significant health hazard due to its ability to cross cellular membranes, bioaccumulate, and biomagnify. In the present research, the effects of short-term (i.e., 24 h) Hg exposure in the symbiont-bearing benthic foraminiferal species Amphistegina lessonii are evaluated using several biomarkers (i.e., proteins and enzymes). Mercury leads to significant changes in the biochemistry of cells. Its effects are mainly associated with oxidative stress (i.e., production of reactive oxygen species: ROS), depletion of glutathione (GSH), and alteration of protein synthesis. Specifically, our findings reveal that exposure to Hg leads to the consumption of GSH by GPx and GST for the scavenging of ROS and the activation of antioxidant-related enzymes, including SOD and GSH-enzymes (GST, GSR, GPx, and Se-GPx), that are directly related to a defense mechanism against ROS. The Hg exposure also activates the MAPK (e.g., p-p38) and HSP (e.g., HSP 70) pathways. The observed biochemical alterations associated with Hg exposure may represent effective and reliable proxies (i.e., biomarkers) for the evaluation of stress in A. lessonii and lead to a possible application for the detection of early warning signs of environmental stress in biomonitoring.

Oxidative Stress in Cancer Immunotherapy: Molecular Mechanisms and Potential Applications

Immunotherapy is an effective treatment option that revolutionizes the management of various cancers. Nevertheless, only a subset of patients receiving immunotherapy exhibit durable responses. Recently, numerous studies have shown that oxidative stress induced by reactive oxygen species (ROS) plays essential regulatory roles in the tumor immune response, thus regulating immunotherapeutic effects. Specifically, studies have revealed key roles of ROS in promoting the release of tumor-associated antigens, manipulating antigen presentation and recognition, regulating immune cell phenotypic differentiation, increasing immune cell tumor infiltration, preventing immune escape and diminishing immune suppression. In the present study, we briefly summarize the main classes of cancer immunotherapeutic strategies and discuss the interplay between oxidative stress and anticancer immunity, with an emphasis on the molecular mechanisms underlying the oxidative stress-regulated treatment response to cancer immunotherapy. Moreover, we highlight the therapeutic opportunities of manipulating oxidative stress to improve the antitumor immune response, which may improve the clinical outcome.

Copper content in ascitic fluid is associated with angiogenesis and progression in ovarian cancer

BACKGROUND

Ascites is associated with the poor prognosis of malignant tumors. The biological importance of the changes in the content of trace elements in the ascitic fluid is unknown. Herein, we analyzed trace elements in the ascitic fluid of patients with ovarian tumors and used cultured cells to determine the copper (Cu)-induced changes in gene expression in ovarian cancer.

METHODS

Inductively coupled plasma mass spectrometry (ICP-MS) was used to compare ascitic fluid trace element levels in patients with benign ovarian tumors (n = 22) and borderline/malignant tumors (n = 5) for primary screening. Cu levels were validated using atomic absorption spectrometry (AAS) in 88 benign, 11 borderline, and 25 malignant ovarian tumor patients. To confirm Cu-induced gene expression changes, microarray analysis was performed for Cu-treated OVCAR3, A2780, and Met5A cells. The vascular endothelial growth factor (VEGF) concentration in the cell supernatant or ascitic fluid (ovarian cancer samples) was measured using ELISA.

RESULTS

ICP-MS showed that Co, Ni, Cu, Zn, As, Se, and Mo levels significantly increased in patients with malignant/borderline ovarian tumors compared to those in patients with benign ovarian tumors. AAS showed that malignant ovarian tumors were independently associated with elevated levels of Cu in ascites adjusted for age, body mass index, alcohol, smoking, and supplement use (p < 0.001). Microarray analysis of both Cu-treated ovarian cancer cell lines OVCAR3 and A2780 and the mesothelial cell line Met-5A revealed the upregulation of the angiogenesis biological process. Real-time polymerase chain reaction and ELISA demonstrated that an increased Cu content significantly enhanced VEGF mRNA expression and protein secretion in OVCAR3, A2780, and Met-5A cells. VEGF levels and clinical stages of the tumors correlated with the ascitic fluid Cu content in patients with malignant ovarian tumors (correlation coefficient 0.445, 95 % confidence interval [CI]: 0.069-0.710, p = 0.023 and correlation coefficient 0.406, 95 % CI: 0.022-0.686, p = 0.040, respectively).

CONCLUSION

Cu levels significantly increased in patients with malignant ovarian cancer. Cu induced angiogenic effects in ovarian cancer and mesothelial cells, which affected ascites fluid production. This study clarifies the link between elevated Cu in ascites and malignant ovarian tumor progression. Strategies to decrease Cu levels in the ascitic fluid may help downregulate VEGF expression, thereby improving the prognosis of ovarian malignancies.

Evidence of micro-evolution in Crocidura russula from two abandoned heavy metal mines: potential use of Cytb, CYP1A1, and p53 as gene biomarkers

Heavy metals accumulated in the environment due to the mining industry may impact on the health of exposed wild animals with consequences at the population level via survival and selection of the most resistant individuals. The detection and quantification of shifts in gene frequencies or in the genetic structure in populations inhabiting polluted sites may be used as early indicators of environmental stress and reveal potential 'candidate gene biomarkers' for environmental health assessment. We had previously observed that specimens of the Greater white-toothed shrew (Crocidura russula) from two heavy metal mines in Southern Portugal (the Aljustrel and the Preguiça mines) carried physiological alterations compared to shrews from an unpolluted site. Here, we further investigated whether these populations showed genetic differences in genes relevant for physiological homeostasis and/or that are associated with pathways altered in animals living under chronic exposure to pollution, and which could be used as biomarkers. We analysed the mitochondrial cytochrome b (Cytb) gene and intronic and/or exonic regions of four nuclear genes: CYP1A1, LCAT, PRPF31, and p53. We observed (1) population differences in allele frequencies, types of variation, and diversity parameters in the Cytb, CYP1A1, and p53 genes; (2) purifying selection of Cytb in the mine populations; (3) genetic differentiation of the two mine populations from the reference by the p53 gene. Adding to our previous observations with Mus spretus, we provide unequivocal evidence of a population effect exerted by the contaminated environment of the mines on the local species of small mammals.

Comparative Fatty Acid Profiling of Edible Fishes in Kuala Terengganu, Malaysia

The aim of this study was to compare the relative nutritional benefit of edible Malaysian fishes from the coast of Terengganu in Malaysia, as well as to perform a taxonomical characterization and metal assessment. Discrimination between species was carried out by a morphological and molecular approach by evaluating the total concentrations of metals by ICP-MS analyses and the fatty acids (FA) composition using the GC–MS approach on the fish fillet tissues. The taxonomical studies detected fishes of 11 families and 13 species. The heavy metal assessment showed that all detected elements did not exceed the regulatory limit stated by Malaysian Food Regulations. The proportion of saturated fatty acids (SFA) ranged from 33 to 58.34%, followed by the polyunsaturated fatty acids (PUFA) values from 24 to 51.8%, and the lowest proportion was of monounsaturated fatty acids (MUFA), ranging from 12.7 to 35.9%. The ω-3/ω-6 PUFA and PUFA/SFA ratios were determined in the range 1.1 to 7.4 and 0.35 to 1.6, respectively. The C20:5 ω-3 and C22:6 ω-3 acids were detected at levels comparable to those found in the corresponding species from similar tropical marine ecosystems. The high FA values can be useful biochemical tools for comparing the relative nutritional benefits of these biodiverse and non-toxic edible Malaysian fishes.

Impacts of wildfires in aquatic organisms: biomarker responses and erythrocyte nuclear abnormalities in Gambusia holbrooki exposed in situ

Wildfires are an environmental concern due to the loss of forest area and biodiversity, but also because their role as drivers of freshwater systems contamination by metals. In this context, the fish Gambusia holbrooki was used as a model, deployed for in situ exposure in watercourses standing within a recently burnt area and further assessment of toxic effects. The fish were exposed during 4 days at four different sites: one upstream and another downstream the burnt area and two within the burnt area. Biochemical biomarkers for oxidative stress and damage were assessed. The extent of lipoperoxidative damage was monitored by quantifying malondialdehyde and DNA damage evaluated through erythrocyte nuclear abnormalities observation. Chemical analysis revealed higher metal levels within the burnt area, and exposed fish consistently showed pro-oxidative responses therein, particularly an increase of gill glutathione peroxidase and glutathione reductase activity, the records doubling compared to samples from sites in the unburnt area; also the activity of glutathione-S-transferases comparatively increased (by 2-fold in the liver) in samples from the burnt area, and malondialdehyde was produced twice as much therein and in samples downstream the burnt area reflecting oxidative damage. Consistently, the frequency of erythrocyte nuclear abnormalities was higher at sites within and downstream the burnt area. This study supports the use of sensitive oxidative stress and genotoxicity biomarkers for an early detection of potentially noxious ecological effects of wildfires runoff.

Mesorhizobium ciceri as biological tool for improving physiological, biochemical and antioxidant state of Cicer aritienum (L.) under fungicide stress

Fungicides among agrochemicals are consistently used in high throughput agricultural practices to protect plants from damaging impact of phytopathogens and hence to optimize crop production. However, the negative impact of fungicides on composition and functions of soil microbiota, plants and via food chain, on human health is a matter of grave concern. Considering such agrochemical threats, the present study was undertaken to know that how fungicide-tolerant symbiotic bacterium, Mesorhizobium ciceri affects the Cicer arietinum crop while growing in kitazin (KITZ) stressed soils under greenhouse conditions. Both in vitro and soil systems, KITZ imparted deleterious impacts on C. arietinum as a function of dose. The three-time more of normal rate of KITZ dose detrimentally but maximally reduced the germination efficiency, vigor index, dry matter production, symbiotic features, leaf pigments and seed attributes of C. arietinum. KITZ-induced morphological alterations in root tips, oxidative damage and cell death in root cells of C. arietinum were visible under scanning electron microscope (SEM). M. ciceri tolerated up to 2400 µg mL-1 of KITZ, synthesized considerable amounts of bioactive molecules including indole-3-acetic-acid (IAA), 1-aminocyclopropane 1-carboxylate (ACC) deaminase, siderophores, exopolysaccharides (EPS), hydrogen cyanide, ammonia, and solubilised inorganic phosphate even in fungicide-stressed media. Following application to soil, M. ciceri improved performance of C. arietinum and enhanced dry biomass production, yield, symbiosis and leaf pigments even in a fungicide-polluted environment. At 96 µg KITZ kg-1 soil, M. ciceri maximally and significantly (p ≤ 0.05) augmented the length of plants by 41%, total dry matter by 18%, carotenoid content by 9%, LHb content by 21%, root N by 9%, shoot P by 11% and pod yield by 15% over control plants. Additionally, the nodule bacterium M. ciceri efficiently colonized the plant rhizosphere/rhizoplane and considerably decreased the levels of stressor molecules (proline and malondialdehyde) and antioxidant defence enzymes viz. ascorbate peroxidise (APX), guaiacol peroxidise (GPX), catalase (CAT) and peroxidises (POD) of C. arietinum plants when inoculated in soil. The symbiotic strain effectively colonized the plant rhizosphere/rhizoplane. Conclusively, the ability to endure higher fungicide concentrations, capacity to secrete plant growth modulators even under fungicide pressure, and inherent features to lower the level of proline and plant defence enzymes makes this M. ciceri as a superb choice for augmenting the safe production of C. arietinum even under fungicide-contaminated soils.

p62 functions as a signal hub in metal carcinogenesis

A number of metals are toxic and carcinogenic to humans. Reactive oxygen species (ROS) play an important role in metal carcinogenesis. Oxidative stress acts as the converging point among various stressors with ROS being the main intracellular signal transducer. In metal-transformed cells, persistent expression of p62 and erythroid 2-related factor 2 (Nrf2) result in apoptosis resistance, angiogenesis, inflammatory microenvironment, and metabolic reprogramming, contributing to overall mechanism of metal carcinogenesis. Autophagy, a conserved intracellular process, maintains cellular homeostasis by facilitating the turnover of protein aggregates, cellular debris, and damaged organelles. In addition to being a substrate of autophagy, p62 is also a crucial molecule in a myriad of cellular functions and in molecular events, which include oxidative stress, inflammation, apoptosis, cell proliferation, metabolic reprogramming, that modulate cell survival and tumor growth. The multiple functions of p62 are appreciated by its ability to interact with several key components involved in various oncogenic pathways. This review summarizes the current knowledge and progress in studies of p62 and metal carcinogenesis with emphasis on oncogenic pathways related to oxidative stress, inflammation, apoptosis, and metabolic reprogramming.

Modulation of Cardiopulmonary Toxicity and Oxidative Stress by Phenolic-Rich Fraction of Croton zambiscus Leaves in Rat Exposed to Chronic Mixture of Environmental Toxicants

Chronic mixed toxicant exposure has been implicated in the aetiology of lung and heart failure through prolonged free radical generations. This study was carried out to assess the protective effect of naturally occurring phenolic components from Croton zambesicus (400 mg/kg C-ZAMB) leaves against cardiopulmonary toxicity induced by chronic mixed toxicant (0.5 mL EOMABRSL) in rats. Chronic cardiopulmonary injury via oral administration of 0.5 ml EOMABRSL for 98 days (non-withdrawal) and 70 days (withdrawal) caused unhealthy alteration in the levels of oxidative stress biomarkers [malondialdehyde (MDA), reduced glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD) and catalase]. Similarly, both withdrawal and non-withdrawal approaches of EOMABRSL-exposed animals exhibited increase in the activity of eco-51-nucleotidase (51ENT) with corresponding diminution in the activity of lactate dehydrogenase (LDH), i.e. the metabolic fuel for cardiopulmonary wellness. Ultimately, histology examination confirmed hyperplastic, bronchopneumonia and cloudy swelling of cardiovascular cells followed by the accumulation of cellular exudates and haemorrhage in the alveoli and bronchioles. The active antioxidants of 400 mg/kg C-ZAMB leaves were responsible for the biological protection of cardiopulmonary toxicity by modulating the activities of 51ENT and LDH. The oxidative stress was also reversed by 400 mg/kg phenolic C-ZAMB leaves in the heart and lungs. Hence, 400 mg/kg phenolic C-ZAMB leaves may be a natural therapy for the treatment of cardiovascular disorder associated with pulmonary dysfunction in rats.

Analyzing dose dependency of antioxidant defense system in the cyanobacterium Nostoc muscorum Meg 1 chronically exposed to Cd2

The aim of the present study was to analyze the dose dependency of oxidant-antioxidant homeostasis in Cd²⁺ exposed Nostoc muscorum Meg 1 cells. Quantification of percent DNA loss, protein oxidation and lipid peroxidation was carried out to assess Cd²⁺ induced ROS mediated damages to the organism. The countermeasures adopted by the cyanobacterium were also evaluated by computing various components of both enzymatic and non-enzymatic antioxidants. Exposure to different Cd²⁺ (0.1, 0.2, 0.3, 0.5, 1, 1.5, 2, 2.5, 3 ppm) doses showed substantial increase in ROS content in the ranges of 20-181% and 116-323% at the end of first and seventh day. The DNA damage, protein oxidation and lipid peroxidation were increased by 11-62%, 7-143% and 13-183% with increasing Cd²⁺ concentrations at the end of seven days. TEM images clearly showed damages to the cell wall, cell membrane and thylakoid organization at higher Cd²⁺ (0.5-3 ppm) concentrations. Cd²⁺ exposure up to 0.5 ppm registered increase in contents of antioxidative enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR)) and in non-enzymatic antioxidants (glutathione, total thiol, phytochelatin and proline) indicating stimulation of ROS mitigating machinery. However, toxicity of Cd²⁺ was evident as at higher concentrations the cellular morphology and ultra-structures were negatively affected and the capacities of the cells to generate various antioxidant measures were highly compromised. The organism registered 96-98% sorption ability from a solution supplemented with 0.3 ppm Cd²⁺ and thus show realistic potential as Cd²⁺ bioremediator in wastewater treatment.

Toxicology of flavoring- and cannabis-containing e-liquids used in electronic delivery systems

Electronic cigarettes (e-cigarettes) were introduced in the United States in 2007 and by 2014 they were the most popular tobacco product amongst youth and had overtaken use of regular tobacco cigarettes. E-cigarettes are used to aerosolize a liquid (e-liquid) that the user inhales. Flavorings in e-liquids is a primary reason for youth to initiate use of e-cigarettes. Evidence is growing in the scientific literature that inhalation of some flavorings is not without risk of harm. In this review, 67 original articles (primarily cellular in vitro) on the toxicity of flavored e-liquids were identified in the PubMed and Scopus databases and evaluated critically. At least 65 individual flavoring ingredients in e-liquids or aerosols from e-cigarettes induced toxicity in the respiratory tract, cardiovascular and circulatory systems, skeletal system, and skin. Cinnamaldehyde was most frequently reported to be cytotoxic, followed by vanillin, menthol, ethyl maltol, ethyl vanillin, benzaldehyde and linalool. Additionally, modern e-cigarettes can be modified to aerosolize cannabis as dried plant material or a concentrated extract. The U.S. experienced an outbreak of lung injuries, termed e-cigarette, or vaping, product use-associated lung injury (EVALI) that began in 2019; among 2,022 hospitalized patients who had data on substance use (as of January 14, 2020), 82% reported using a delta-9-tetrahydrocannabinol (main psychoactive component in cannabis) containing e-cigarette, or vaping, product. Our literature search identified 33 articles related to EVALI. Vitamin E acetate, a diluent and thickening agent in cannabis-based products, was strongly linked to the EVALI outbreak in epidemiologic and laboratory studies; however, e-liquid chemistry is highly complex, and more than one mechanism of lung injury, ingredient, or thermal breakdown product may be responsible for toxicity. More research is needed, particularly with regard to e-cigarettes (generation, power settings, etc.), e-liquids (composition, bulk or vaped form), modeled systems (cell type, culture type, and dosimetry metrics), biological monitoring, secondhand exposures and contact with residues that contain nicotine and flavorings, and causative agents and mechanisms of EVALI toxicity.

Transcriptome Analysis Reveals HgCl2 Induces Apoptotic Cell Death in Human Lung Carcinoma H1299 Cells through Caspase-3-Independent Pathway

Mercury is one of the detrimental toxicants that can be found in the environment and exists naturally in different forms; inorganic and organic. Human exposure to inorganic mercury, such as mercury chloride, occurs through air pollution, absorption of food or water, and personal care products. This study aimed to investigate the effect of HgCl₂ on cell viability, cell cycle, apoptotic pathway, and alters of the transcriptome profiles in human non-small cell lung cancer cells, H1299. Our data show that HgCl₂ treatment causes inhibition of cell growth via cell cycle arrest at G₀/G₁- and S-phase. In addition, HgCl₂ induces apoptotic cell death through the caspase-3-independent pathway. Comprehensive transcriptome analysis using RNA-seq indicated that cellular nitrogen compound metabolic process, cellular metabolism, and translation for biological processes-related gene sets were significantly up- and downregulated by HgCl₂ treatment. Interestingly, comparative gene expression patterns by RNA-seq indicated that mitochondrial ribosomal proteins were markedly altered by low-dose of HgCl₂ treatment. Altogether, these data show that HgCl₂ induces apoptotic cell death through the dysfunction of mitochondria.

Biochemical and histopathological effects of low dose vanadium in the healing of acetic acid-induced colitis in male wistar rats

OBJECTIVES

Vanadium has been reported to possess relevant therapeutic properties such as anti-diabetic and anti-tumoral. This study aimed at determining the effects of vanadium on experimentally induced colitis in rats.

METHODS

Forty-five male Wistar rats (103 ± 3.90 g, n=15) were used for this study and were divided into three groups. Group 1 (Untreated control) had nothing added to their drinking, while groups 2 and 3 received sodium metavanadate at a dose of 50 and 200 mg/L respectively in their drinking water for 10 weeks. Colitis was thereafter induced by intra colonic administration of 1.50 mL of 6% acetic acid. Animals were sacrificed on day 0 (pre-induction), three- and seven-days post induction. Blood samples were collected for haematological variables and the distal 8 cm of the colon was collected for macroscopic, histological and biochemical (malondialdehyde-MDA, superoxide dismutase-SOD, catalase-CAT, glutathione peroxidase- GPx and nitrite concentration- NO) assessment.

RESULTS

Low dose vanadium proved beneficial in ameliorating acetic acid-induced colitis by improving both histopathological and haematological changes. Gross observation showed a faster healing rate in vanadium treated groups (50 and 200 mg/L) compared with untreated control at day 3 (40 and 26.20 vs. 2.50%) and day 7 (80 and 66.70 vs. 42%) respectively. Vanadium also appears to exert its beneficial effects on acetic acid-induced colitis via up regulation of antioxidant enzymes (SOD, CAT, GPx) and NO while decreasing the over production of MDA.

CONCLUSIONS

Vanadium at small concentration functions as an essential trace element and may be able to promote healing process during ulcerative colitis.

A multibiomarker approach in the caged neotropical fish to assess the environment health in a river of central Brazilian Cerrado

Water safety is a world-wide concern and several efforts have been made in order to ensure the conservation of aquatic ecosystems. Water quality monitoring must be performed with an integrated approach using biomonitor organisms allied to water parameters. Nonetheless, very few studies have focused on biomarker responses in neotropical fish, especially in the freshwater ecosystem of Brazilian Cerrado savanna. In present study, the active biomonitoring of the João Leite river (central Brazilian Cerrado river) was performed through the evaluation of biomarker responses in caged Astyanax lacustris in combination with land use classification and analysis of water parameters. Caged fish were exposed for seven days at four sites along the river and two control groups were kept in a tank under controlled conditions. Results showed that pasture was the predominant land use in the João Leite river basin (54.07%), followed by natural vegetation (34.92%) and other kind of land use (11.01%). Water analyses showed metal concentrations (Mn and Fe) above the maximum allowed by Brazilian regulation, with particularly higher concentrations at Site 2 (near to pasture area). Biomarker responses did not show significant differences for somatic and mutagenic biomarkers between sites. However, the comet assay showed high DNA damage at Sites 2 and 3, indicating genotoxic effects in caged fish at pasture areas. Histopathological analysis showed highest frequency of leukocyte infiltration in liver of fish from Site 2, confirming the ecotoxic effects on A. lacustris in streams impacted by grazing activities. DNA damage and leukocyte infiltration in fish hepatic tissues were sensitive biomarkers in the neotropical fish A. lacustris to assess the environment health of the Cerrado river. These results showed the importance of using a multibiomarker approach in environmental risk assessment, especially in areas more at risk from anthropogenic pollution.

Toxic Prediction of Pyrrolizidine Alkaloids and Structure-Dependent Induction of Apoptosis in HepaRG Cells

Pyrrolizidine alkaloids (PAs) are common phytotoxins and could cause liver genotoxicity/carcinogenicity following metabolic activation. However, the toxicity of different structures remains unclear due to the wide variety of PAs. In this study, the absorption, distribution, metabolism, excretion, and toxicity (ADMET) of 40 PAs were analyzed, and their toxicity was predicted by Komputer Assisted Technology (TOPKAT) using Discovery Studio software. The in silico results showed that all PAs except retronecine had good intestinal absorption, and all PAs were predicted to have different toxicity ranges. To verify the predictive results, 4 PAs were selected to investigate cell injury and possible mechanisms of the differentiation in HepaRG cells, including retronecine type of twelve-membered cyclic diester (retrorsine), eleven-membered cyclic diester (monocrotaline), noncyclic diester (retronecine), and platynecine type (platyphylline). After 24 h exposure, retronecine-type PAs exhibited concentration-dependent cytotoxicity. The high-content screening assay showed that cell oxidative stress, mitochondrial damage, endoplasmic reticulum stress, and the concentration of calcium ions increased, and neutral lipid metabolism was changed notably in HepaRG cells. Induced apoptosis by PAs was indicated by cell cycle arrest in the G2/M phase, disrupting the mitochondrial membrane potential. Overall, our study revealed structure-dependent cytotoxicity and apoptosis after PA exposure, suggesting that the prediction results of in silico have certain reference values for compound toxicity. A 1,2-membered cyclic diester seems to be a more potent apoptosis inducer than other PAs.

Current understanding of nanoparticle toxicity mechanisms and interactions with biological systems

Nanotechnology is an emerging science involving the manipulation of matter on the nanometer scale.

Biological effects of inhaled hydraulic fracturing sand dust. III. Cytotoxicity and pro-inflammatory responses in cultured murine macrophage cells

Cultured murine macrophages (RAW 264.7) were used to investigate the effects of fracking sand dust (FSD) for its pro-inflammatory activity, in order to gain insight into the potential toxicity to workers associated with inhalation of FSD during hydraulic fracturing. While the role of respirable crystalline silica in the development of silicosis is well documented, nothing is known about the toxicity of inhaled FSD. The FSD (FSD 8) used in these studies was from an unconventional gas well drilling site. FSD 8was prepared as a 10 mg/ml stock solution in sterile PBS, vortexed for 15 s, and allowed to sit at room temperature for 30 min before applying the suspension to RAW 264.7cells. Compared to PBS controls, cellular viability was significantly decreased after a 24 h exposure to FSD. Intracellular reactive oxygen species (ROS) production and the production of IL-6, TNFα, and endothelin-1 (ET-1) were up-regulated as a result of the exposure, whereas the hydroxyl radical (.OH) was only detected in an acellular system. Immunofluorescent staining of cells against TNFα revealed that FSD 8 caused cellular blebbing, and engulfment of FSD 8 by macrophages was observed with enhanced dark-field microscopy. The observed changes in cellular viability, cellular morphology, free radical generation and cytokine production all confirm that FSD 8 is cytotoxic to RAW 264.7 cells and warrants future studies into the specific pathways and mechanisms by which these toxicities occur.

Perfusion reduces bispecific antibody aggregation via mitigating mitochondrial dysfunction-induced glutathione oxidation and ER stress in CHO cells

One major challenge observed for the expression of therapeutic bispecific antibodies (BisAbs) is high product aggregates. Aggregates increase the risk of immune responses in patients and therefore must be removed at the expense of purification yields. BisAbs contain engineered disulfide bonds, which have been demonstrated to form product aggregates, if mispaired. However, the underlying intracellular mechanisms leading to product aggregate formation remain unknown. We demonstrate that impaired glutathione regulation underlies BisAb aggregation formation in a CHO cell process. Aggregate formation was evaluated for the same clonal CHO cell line producing a BisAb using fed-batch and perfusion processes. The perfusion process produced significantly lower BisAb aggregates compared to the fed-batch process. Perfusion bioreactors attenuated mitochondrial dysfunction and ER stress resulting in a favorable intracellular redox environment as indicated by improved reduced to oxidized glutathione ratio. Conversely, mitochondrial dysfunction-induced glutathione oxidation and ER stress disrupted the intracellular redox homeostasis, leading to product aggregation in the fed-batch process. Combined, our results demonstrate that mitochondrial dysfunction and ER stress impaired glutathione regulation leading to higher product aggregates in the fed-batch process. This is the first study to utilize perfusion bioreactors as a tool to demonstrate the intracellular mechanisms underlying product aggregation formation.

Metals and molecular carcinogenesis

Many metals are essential for living organisms, but at higher doses they may be toxic and carcinogenic. Metal exposure occurs mainly in occupational settings and environmental contaminations in drinking water, air pollution and foods, which can result in serious health problems such as cancer. Arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr) and nickel (Ni) are classified as Group 1 carcinogens by the International Agency for Research on Cancer. This review provides a comprehensive summary of current concepts of the molecular mechanisms of metal-induced carcinogenesis and focusing on a variety of pathways, including genotoxicity, mutagenesis, oxidative stress, epigenetic modifications such as DNA methylation, histone post-translational modification and alteration in microRNA regulation, competition with essential metal ions and cancer-related signaling pathways. This review takes a broader perspective and aims to assist in guiding future research with respect to the prevention and therapy of metal exposure in human diseases including cancer.