Copper induces--and copper chelation by tetrathiomolybdate inhibits--endothelial activation in vitro

Essential and Non-Essential Metals and Metalloids and Their Role in Atherosclerosis

Peripheral arterial disease (PAD) is becoming more prevalent in the aging developed world and can have significant functional impacts on patients. There is a recent recognition that environmental toxicants such as circulating metals and metalloids may contribute to the pathogenesis of atherosclerotic disease, but the mechanisms are complex. While the broad toxic biologic effects of metals in human systems have been extensively reviewed, the role of non-essential exposure and essential metal aberrancy in PAD specifically is less frequently discussed. This review of the literature describes current scientific knowledge regarding the individual roles several major metals and metalloids play in atherogenesis and highlights areas where a dearth of data exist. The roles of lead (Pb), arsenic (As), cadmium (Cd), iron (Fe), copper (Cu), selenium (Se) are included. Contemporary outcomes of therapeutic trials aimed at chelation therapy of circulating metals to impact cardiovascular outcomes are also discussed. This review highlights the supported notion of differential metal presence within peripheral plaques themselves, although distinguishing their roles within these plaques requires further illumination.

Superoxide is an Intrinsic Signaling Molecule Triggering Muscle Hypertrophy

Aims: Redox signaling plays a key role in skeletal muscle remodeling induced by exercise and prolonged inactivity, but it is unclear which oxidant triggers myofiber hypertrophy due to the lack of strategies to precisely regulate individual oxidants in vivo. In this study, we used tetrathiomolybdate (TM) to dissociate the link between superoxide (O2•-) and hydrogen peroxide and thereby to specifically explore the role of O2•- in muscle hypertrophy in C2C12 cells and mice. Results: TM can linearly regulate intracellular O2•- levels by inhibition of superoxide dismutase 1 (SOD1). A 70% increase in O2•- levels in C2C12 myoblast cells and mice is necessary and sufficient for triggering hypertrophy of differentiated myotubes and can enhance exercise performance by more than 50% in mice. SOD1 knockout blocks TM-induced O2•- increments and thereby prevents hypertrophy, whereas SOD1 restoration rescues all these effects. Scavenging O2•- with antioxidants abolishes TM-induced hypertrophy and the enhancement of exercise performance, whereas the restoration of O2•- levels with a O2•- generator promotes muscle hypertrophy independent of SOD1 activity. Innovation and Conclusion: These findings suggest that O2•- is an endogenous initiator of myofiber hypertrophy and that TM may be used to treat muscle wasting diseases. Our work not only suggests a novel druggable mechanism to increase muscle mass but also provides a tool for precisely regulating O2•- levels in vivo. Antioxid. Redox Signal. 42, 1-15.

Copper Promotes LPS-Induced Inflammation via the NF-кB Pathway in Bovine Macrophages

Inflammation is a complex physiological process that enables the clearance of pathogens and repairing damaged tissues. Elevated serum copper concentration has been reported in cases of inflammation, but the role of copper in inflammatory responses remains unclear. This study used bovine macrophages to establish lipopolysaccharide (LPS)-induced inflammation model. There were five groups in the study: a group treated with LPS (100 ng/ml), a group treated with either copper chelator (tetrathiomolybdate, TTM) (20 μmol) or CuSO4 (25 μmol or 50 μmol) after LPS stimulation, and a control group. Copper concentrations increased in macrophages after the LPS treatment. TTM decreased mRNA expression of pro-inflammatory factors (IL-1β, TNF-α, IL-6, iNOS, and COX-2), whereas copper supplement increased them. Compared to the control group, TLP4 and MyD88 protein levels were increased in the TTM and copper groups. However, TTM treatment decreased p-p65 and increased IкB-α while the copper supplement showed reversed results. In addition, the phagocytosis and migration of bovine macrophages decreased in the TTM treatment group while increased in the copper treatment groups. Results mentioned above indicated that copper could promote the LPS-induced inflammatory response in bovine macrophages, promote pro-inflammatory factors by activating the NF-кB pathway, and increase phagocytosis capacity and migration. Our study provides a possible targeted therapy for bovine inflammation.

Deciphering the Role of Copper Homeostasis in Atherosclerosis: From Molecular Mechanisms to Therapeutic Targets

Cardiovascular disease (CVD) is a leading cause of death globally, with atherosclerosis (AS) playing a central role in its pathogenesis as a chronic inflammatory condition. Copper, an essential trace element in the human body, participates in various biological processes and plays a significant role in the cardiovascular system. Maintaining normal copper homeostasis is crucial for cardiovascular health, and dysregulation of copper balance is closely associated with the development of CVD. When copper homeostasis is disrupted, it can induce cell death, which has been proposed to be a novel form of "cuproptosis", distinct from traditional programmed cell death. This new form of cell death is closely linked to the occurrence and progression of AS. This article elaborately describes the physiological mechanisms of copper homeostasis and explores its interactions with signaling pathways related to AS. Additionally, we focus on the process and mechanism of cell death induced by imbalances in copper homeostasis and summarize the relationship between copper homeostasis-related genes and AS. We also emphasize potential therapeutic approaches, such as copper balance regulators and nanotechnology interventions, to adjust copper levels in the body, providing new ideas and strategies for the prevention and treatment of CVD.

Cuproptosis and Cu: a new paradigm in cellular death and their role in non-cancerous diseases

Cuproptosis, a newly characterized form of regulated cell death driven by copper accumulation, has emerged as a significant mechanism underlying various non-cancerous diseases. This review delves into the complex interplay between copper metabolism and the pathogenesis of conditions such as Wilson's disease (WD), neurodegenerative disorders, and cardiovascular pathologies. We examine the molecular mechanisms by which copper dysregulation induces cuproptosis, highlighting the pivotal roles of key copper transporters and enzymes. Additionally, we evaluate the therapeutic potential of copper chelation strategies, which have shown promise in experimental models by mitigating copper-induced cellular damage and restoring physiological homeostasis. Through a comprehensive synthesis of recent advancements and current knowledge, this review underscores the necessity of further research to translate these findings into clinical applications. The ultimate goal is to harness the therapeutic potential of targeting cuproptosis, thereby improving disease management and patient outcomes in non-cancerous conditions associated with copper dysregulation.

Copper Chelation Therapy Attenuates Periodontitis Inflammation through the Cuproptosis/Autophagy/Lysosome Axis

Periodontitis development arises from the intricate interplay between bacterial biofilms and the host's immune response, where macrophages serve pivotal roles in defense and tissue homeostasis. Here, we uncover the mitigative effect of copper chelator Tetrathiomolybdate (TTM) on periodontitis through inhibiting cuproptosis, a newly identified form of cell death which is dependent on copper. Our study reveals concurrent cuproptosis and a macrophage marker within murine models. In response to lipopolysaccharide (LPS) stimulation, macrophages exhibit elevated cuproptosis-associated markers, which are mitigated by the administration of TTM. TTM treatment enhances autophagosome expression and mitophagy-related gene expression, countering the LPS-induced inhibition of autophagy flux. TTM also attenuates the LPS-induced fusion of autophagosomes and lysosomes, the degradation of lysosomal acidic environments, lysosomal membrane permeability increase, and cathepsin B secretion. In mice with periodontitis, TTM reduces cuproptosis, enhances autophagy flux, and decreases Ctsb levels. Our findings underscore the crucial role of copper-chelating agent TTM in regulating the cuproptosis/mitophagy/lysosome pathway during periodontitis inflammation, suggesting TTM as a promising approach to alleviate macrophage dysfunction. Modulating cuproptosis through TTM treatment holds potential for periodontitis intervention.

Copper homeostasis and copper-induced cell death： Novel targeting for intervention in the pathogenesis of vascular aging

Copper-induced cell death, also known as cuproptosis, is distinct from other types of cell death such as apoptosis, necrosis, and ferroptosis. It can trigger the accumulation of lethal reactive oxygen species, leading to the onset and progression of aging. The significant increases in copper ion levels in the aging populations confirm a close relationship between copper homeostasis and vascular aging. On the other hand, vascular aging is also closely related to the occurrence of various cardiovascular diseases throughout the aging process. However, the specific causes of vascular aging are not clear, and different living environments and stress patterns can lead to individualized vascular aging. By exploring the correlations between copper-induced cell death and vascular aging, we can gain a novel perspective on the pathogenesis of vascular aging and enhance the prognosis of atherosclerosis. This article aims to provide a comprehensive review of the impacts of copper homeostasis on vascular aging, including their effects on endothelial cells, smooth muscle cells, oxidative stress, ferroptosis, intestinal flora, and other related factors. Furthermore, we intend to discuss potential strategies involving cuproptosis and provide new insights for copper-related vascular aging.

Transition metals in angiogenesis - A narrative review

The aim of this paper is to offer a narrative review of the literature regarding the influence of transition metals on angiogenesis, excluding lanthanides and actinides. To our knowledge there are not any reviews up to date offering such a summary, which inclined us to write this paper. Angiogenesis describes the process of blood vessel formation, which is an essential requirement for human growth and development. When the complex interplay between pro- and antiangiogenic mediators falls out of balance, angiogenesis can quickly become harmful. As it is so fundamental, both its inhibition and enhancement take part in various diseases, making it a target for therapeutic treatments. Current methods come with limitations, therefore, novel agents are constantly being researched, with metal agents offering promising results. Various transition metals have already been investigated in-depth, with studies indicating both pro- and antiangiogenic properties, respectively. The transition metals are being applied in various formulations, such as nanoparticles, complexes, or scaffold materials. Albeit the increasing attention this field is receiving, there remain many unanswered questions, mostly regarding the molecular mechanisms behind the observed effects. Notably, approximately half of all the transition metals have not yet been investigated regarding potential angiogenic effects. Considering the promising results which have already been established, it should be of great interest to begin investigating the remaining elements whilst also further analyzing the established effects.

Crosstalk between trace elements and T-cell immunity during early-life health in pigs

With gradual ban on the use of antibiotics, the deficiency and excessive use of trace elements in intestinal health is gaining attention. In mammals, trace elements are essential for the development of the immune system, specifically T-cell proliferation, and differentiation. However, there remain significant gaps in our understanding of the effects of certain trace elements on T-cell immune phenotypes and functions in pigs. In this review, we summarize the specificity, development, subpopulations, and responses to pathogens of porcine T cells and the effects of functional trace elements (e.g., iron, copper, zinc, and selenium) on intestinal T-cell immunity during early-life health in pigs. Furthermore, we discuss the current trends of research on the crosstalk mechanisms between trace elements and T-cell immunity. The present review expands our knowledge of the association between trace elements and T-cell immunity and provides an opportunity to utilize the metabolism of trace elements as a target to treat various diseases.

The copper chelator ammonium tetrathiomolybdate inhibits the progression of experimental endometriosis in TNFR1-deficient mice

The TNF-α/TNFR system is involved in endometriosis (EDT), a gynecologic estrogen-dependent disease. Elevated copper concentrations have also been associated with EDT, even in TNFR1-deficient mice where disease worsening occurs. We aimed to evaluate whether treatment with ammonium tetrathiomolybdate (TM, copper chelator) is beneficial in TNFR1-deficient mice presenting with worsened EDT status. Female C57BL/6 mice were divided into three groups: KO Sham, KO EDT, and KO EDT+TM. TM was administered from the 15th postoperative day, and samples were collected one month after inducing pathology. In peritoneal fluid, copper and estradiol levels were determined by electrothermal atomic absorption spectrometry and electrochemiluminescence, respectively. Lesions were processed for the analysis of cell proliferation (PCNA immunohistochemistry), expression of angiogenic markers (RT-qPCR), and oxidative stress (spectrophotometric methods). We found that EDT increased copper and estradiol levels compared to the KO Sham group, while the TM administration restored the levels of both factors. TM also reduced the volume and weight of the lesions and cell proliferation rate. Besides, TM treatment decreased the number of blood vessels and the Vegfa, Fgf2, and Pdgfb expression. Furthermore, superoxide dismutase and catalase activity decreased, and lipid peroxidation increased. TM administration inhibits EDT progression in TNFR1-deficient mice where the pathology is exacerbated.

Identification of Three Cuproptosis-specific Expressed Genes as Diagnostic Biomarkers and Therapeutic Targets for Atherosclerosis

Atherosclerosis is a chronic, inflammatory disease characterized by a lipid-driven infiltration of inflammatory cells in large and medium arteries and is considered to be a major underlying cause of cardiovascular diseases. Cuproptosis, a novel form of cell death, is highly linked to mitochondrial metabolism and mediated by protein lipoylation. However, the clinical implication of cuproptosis-related genes (CRGs) in atherosclerosis remains unclear. In this study, genes collected from the GEO database intersected with CRGs were identified in atherosclerosis. GSEA, GO and KEGG pathway enrichment analyses were performed for functional annotation. Through the random forest algorithm and the construction of a protein-protein interaction (PPI) network, eight selected genes (LOXL2, SLC31A1, ATP7A, SLC31A2, COA6, UBE2D1, CP and SOD1) and a vital cuproptosis-related gene FDX1 were then further validated. Two independent datasets (GSE28829 (N = 29), GSE100927 (N = 104)) were collected to construct the signature of CRGs for validation in atherosclerosis. Consistently, the atherosclerosis plaques showed significantly higher expression of SLC31A1, SLC31A2 and lower expression of SOD1 than the normal intimae. The area under the curve (AUC) of SLC31A1, SLC31A2 and SOD1 performed well for the diagnostic validation in the two datasets. In conclusion, the cuproptosis-related gene signature could serve as a potential diagnostic biomarker for atherosclerosis and may offer novel insights into the treatment of cardiovascular diseases. Based on the hub genes, a competing endogenous RNA (ceRNA) network of lncRNA-miRNA-mRNA and a transcription factor regulation network were ultimately constructed to explore the possible regulatory mechanism in atherosclerosis.

Essential Trace Element Status in Systemic Lupus Erythematosus: a Meta-analysis Based on Case-Control Studies

The homeostasis of trace elements is essential to regulate different aspects of the immune system and might play important roles in systemic lupus erythematosus (SLE). However, epidemiological evidences that compared the level of essential trace elements in SLE patients and healthy controls (HCs) did not reach a consensus. This was the first meta-analysis to comprehensively assess the level of zinc (Zn), copper (Cu), iron (Fe), and selenium (Se) in SLE and HCs. PubMed, Embase, and Web of Science were systematically searched until April 2022 to find relevant literatures. The PRISMA statement 2020 was followed to make sure the quality of reporting a meta-analysis. The outcomes were assessed by pooled standardized mean difference (SMD) and 95% confidence intervals (CIs). Finally, eleven articles with 1262 subjects were included in the meta-analysis. Significantly lower levels of Zn (SMD = -0.709; 95% CI: -1.173, -0.245; P = 0.003) and Fe (SMD = -1.783; 95% CI: -2.756, -0.809; P = 0.000) were found in SLE compared with HCs. Higher levels of Cu (SMD = 0.808; 95% CI: 0.234, 1.382; P = 0.006) were found in SLE patients. In addition, compared with HCs, Fe and Zn were lower in SLE patients in Asia and Cu was higher in SLE patients in Europe. However, no significant difference was observed in the level of Se (SMD = -0.251; 95% CI: -1.087, 0.586; P = 0.557). Above all, SLE patients exhibited lower Zn and Fe and increased Cu concentrations compared with HCs. Further studies are warranted to investigate the mechanism of Zn, Cu, and Fe in SLE patients.

In silico identification of molecular mechanisms for stroke risk caused by heavy metals and their mixtures: sponges and drugs involved

This study used various approaches and databases to evaluate the molecular processes and identify miRNA sponges and drugs associated with the development of stroke caused by heavy metals and their combinations. We found that the genes ALB (albumin), IL1B (Interleukin-1β), F2 (coagulation factor II), APOA1 (apolipoprotein A1), IL6 (Interleukin 6), and NOS2 (nitric oxide synthase 2) were linked to the development of strokes by 18 chemicals and a combination of cadmium, copper, and lead. These results may point to the significance of detoxification and neuroinflammation in stroke as well as the potential for targeting these genes in future stroke therapies. ALB and IL1B were the most common and significant genes. The "selenium micronutrient network," "vitamin B12 metabolism," and "folate metabolism" were shown to be the most significant pathways connected to the risk of stroke brought on by combined heavy metals. The two main cellular elements that may increase the risk of stroke caused by heavy metals were discovered to be "blood microparticle" and "endoplasmic reticulum lumen." We also observed an important chromosome (chr7p15.3), two transcription factors (NFKB2 [nuclear factor kappa B subunit 2] and NR1I2 [nuclear receptor subfamily 1 group, member 2]), and four microRNAs (hsa-miR-26a-5p, hsa-miR-9-5p, hsa-miR-124-3p, and hsa-miR-155-5p) associated with stroke caused by combined heavy metals. Additionally, for these miRNAs, we created and examined in silico microRNA sponge sequences. Triflusal and andrographolide have been identified as potential treatments for heavy metal-induced stroke. Taken together, heavy metals may be a significant contributor to the pathophysiology of stroke, but further investigation into the precise molecular pathways implicated in stroke pathophysiology is required to corroborate these findings.

Molybdenum fertilizer improved antioxidant capacity of Chinese Merino sheep under compound contamination

To investigate the response of different levels of molybdenum (Mo) fertilizer to Chinese Merino sheep (Junken Type) grazing on natural heavy metal-contaminated meadows, this study was carried out in the Bayanbulak Grassland lying in the northwest of Xinjiang Uygur Autonomous Region, China. A total of 24-hm2 polluted meadows were fenced and were randomly divided into four groups (3 replication/group and 2 hm2/replication) applied 0-kg Mo, 1-kg Mo, 2-kg Mo, and 3-kg Mo (ammonium molybdate tetrahydrate) per hectare for the CON group, group I, group II, and group III, respectively. Seventy-two healthy 1-year-old Chinese Merino sheep (45.56 ± 2.35 kg) were randomly assigned to the tested pastures for 90 days. Compared with the CON group, the Mo content from fertilized groups and the Se content from group II and group III in serums and livers were significantly increased (P < 0.05), and the Cu content from fertilized groups in serums and livers was significantly decreased (P < 0.05). The levels of blood Hb and RBC, and the activities of serum SOD, CAT, GSH-Px, and Cp in group III, were significantly higher (P < 0.05) than those in the CON group, group I, and group II. Serum MDA content in group III was significantly lower (P < 0.05) than that in the other three groups. In summary, Mo fertilization improved the antioxidant capacity of grazing sheep and also reduced the toxic damage to Chinese Merino sheep grazing on natural grasslands contaminated by heavy metals, but Mo poisoning caused by excessive fertilization should be prevented.

Among Gerontogens, Heavy Metals Are a Class of Their Own: A Review of the Evidence for Cellular Senescence

Advancements in modern medicine have improved the quality of life across the globe and increased the average lifespan of our population by multiple decades. Current estimates predict by 2030, 12% of the global population will reach a geriatric age and live another 3-4 decades. This swelling geriatric population will place critical stress on healthcare infrastructures due to accompanying increases in age-related diseases and comorbidities. While much research focused on long-lived individuals seeks to answer questions regarding how to age healthier, there is a deficit in research investigating what aspects of our lives accelerate or exacerbate aging. In particular, heavy metals are recognized as a significant threat to human health with links to a plethora of age-related diseases, and have widespread human exposures from occupational, medical, or environmental settings. We believe heavy metals ought to be classified as a class of gerontogens (i.e., chemicals that accelerate biological aging in cells and tissues). Gerontogens may be best studied through their effects on the "Hallmarks of Aging", nine physiological hallmarks demonstrated to occur in aged cells, tissues, and bodies. Evidence suggests that cellular senescence-a permanent growth arrest in cells-is one of the most pertinent hallmarks of aging and is a useful indicator of aging in tissues. Here, we discuss the roles of heavy metals in brain aging. We briefly discuss brain aging in general, then expand upon observations for heavy metals contributing to age-related neurodegenerative disorders. We particularly emphasize the roles and observations of cellular senescence in neurodegenerative diseases. Finally, we discuss the observations for heavy metals inducing cellular senescence. The glaring lack of knowledge about gerontogens and gerontogenic mechanisms necessitates greater research in the field, especially in the context of the global aging crisis.

Alleviative effects of a novel strain Bacillus coagulans XY2 on copper-induced toxicity in zebrafish larvae

Copper (Cu) is a kind of micronutrient element that is essential for human metabolism. However, it is also considered as an environmental pollutant which is toxic to organisms at a high concentration level. Probiotics, regarded as beneficial microorganisms for promoting human health, have functions of antioxidant capacity, immune-enhancing properties, intestinal barrier protection and regulation. Several studies have reported that probiotics show positive effects on alleviating and intervening heavy metals toxicity. However, evidence for relieving copper-induced toxicity by probiotics is still limited. In this study, we firstly conducted a zebrafish larvae model to screen out microorganisms which are helpful for CuSO₄ toxicity resistance and one novel strain named as Bacillus coagulans XY2 was discovered with the best protective activity. B. coagulans XY2 significantly reduced the mortality of zebrafish larvae exposed to 10 µmol/L CuSO₄ for 96 hr, as well as alleviated the neutrophils infiltration in the larvae lateral line under a 2 hr exposure. B. coagulans XY2 exhibited a high in vitro antioxidant activity and against CuSO₄-induced oxidative stress in zebrafish larvae by up-regulating sod1, gstp1 and cat gene transcriptional levels and relevant enzymatic activities. CuSO₄ stimulated the inflammation process resulting in obvious increases of gene il-1β and il-10 transcription, which were suppressed by B. coagulans XY2 intervention. Overall, our results underline the bio-function of B. coagulans XY2 on protecting zebrafish larvae from copper toxicity, suggesting the potential application values of probiotics in copper toxicity alleviation on human and the environment.

The Dysregulation of Inflammatory Pathways Triggered by Copper Exposure

Copper (Cu) is an essential micronutrient for both human and animals. However, excessive intake of copper will cause damage to organs and cells. Inflammation is a biological response that can be induced by various factors such as pathogens, damaged cells, and toxic compounds. Dysregulation of inflammatory responses are closely related to many chronic diseases. Recently, Cu toxicological and inflammatory effects have been investigated in various animal models and cells. In this review, we summarized the known effect of Cu on inflammatory responses and sum up the molecular mechanism of Cu-regulated inflammation. Excessive Cu exposure can modulate a huge number of cytokines in both directions, increase and/or decrease through a variety of molecular and cellular signaling pathways including nuclear factor kappa-B (NF-κB) pathway, mitogen-activated protein kinase (MAPKs) pathway, JAK-STAT (Janus Kinase- signal transducer and activator of transcription) pathway, and NOD-like receptor protein 3 (NLRP3) inflammasome. Underlying the molecular mechanism of Cu-regulated inflammation could help further understanding copper toxicology and copper-associated diseases.

Copper homeostasis and cuproptosis in health and disease

As an essential micronutrient, copper is required for a wide range of physiological processes in virtually all cell types. Because the accumulation of intracellular copper can induce oxidative stress and perturbing cellular function, copper homeostasis is tightly regulated. Recent studies identified a novel copper-dependent form of cell death called cuproptosis, which is distinct from all other known pathways underlying cell death. Cuproptosis occurs via copper binding to lipoylated enzymes in the tricarboxylic acid (TCA) cycle, which leads to subsequent protein aggregation, proteotoxic stress, and ultimately cell death. Here, we summarize our current knowledge regarding copper metabolism, copper-related disease, the characteristics of cuproptosis, and the mechanisms that regulate cuproptosis. In addition, we discuss the implications of cuproptosis in the pathogenesis of various disease conditions, including Wilson's disease, neurodegenerative diseases, and cancer, and we discuss the therapeutic potential of targeting cuproptosis.

Histological alterations, oxidative stress, and inflammatory response in the liver of swamp eel (Monopterus albus) acutely exposed to copper

Copper (Cu) is widely used as an essential trace element in diets as well as a therapeutic chemical. However, excessive Cu has deleterious effects on organisms, including teleosts. Although numerous toxic effects of Cu have been reported, the effects of Cu exposure on the swamp eel (Monopterus albus) as well as the underlying mechanisms have not yet been elucidated. In this study, swamp eels were acutely exposed to 100, 200, and 400 μg/L of Cu for 96 h to evaluate liver histopathology, oxidative stress, and inflammation. Dissolution of hepatocyte membrane, vacuolar degeneration, and inflammatory cell infiltration were detected in the livers of the Cu-treated swamp eels, especially in the 400 μg Cu/L group. Cu-induced hepatic dysfunction was further verified by the elevated activities of glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) and transcript levels of GOT and GPT genes. In addition, Cu exposure decreased the activities of total superoxide dismutase T-SOD and catalase (CAT) and the contents of glutathione (GSH) and total antioxidant capacity (T-AOC) and increased the levels of malondialdehyde (MDA). Cu exposure also significantly decreased the transcript levels of glutathione synthetase (GSS) and increased the transcript levels of SOD1, SOD2, CAT, and heme oxygenase-1 (HO-1) genes. Furthermore, pro-inflammatory genes such as interleukin (IL)-1β, tumor necrosis factor-α (TNF-α), and IL-8 were significantly upregulated. These results indicate that Cu induces oxidative stress and inflammatory response and causes pathological changes in the liver of the swamp eel.

Heavy Metal-Induced Cerebral Small Vessel Disease: Insights into Molecular Mechanisms and Possible Reversal Strategies

Heavy metals are considered a continuous threat to humanity, as they cannot be eradicated. Prolonged exposure to heavy metals/metalloids in humans has been associated with several health risks, including neurodegeneration, vascular dysfunction, metabolic disorders, cancer, etc. Small blood vessels are highly vulnerable to heavy metals as they are directly exposed to the blood circulatory system, which has comparatively higher concentration of heavy metals than other organs. Cerebral small vessel disease (CSVD) is an umbrella term used to describe various pathological processes that affect the cerebral small blood vessels and is accepted as a primary contributor in associated disorders, such as dementia, cognitive disabilities, mood disorder, and ischemic, as well as a hemorrhagic stroke. In this review, we discuss the possible implication of heavy metals/metalloid exposure in CSVD and its associated disorders based on in-vitro, preclinical, and clinical evidences. We briefly discuss the CSVD, prevalence, epidemiology, and risk factors for development such as genetic, traditional, and environmental factors. Toxic effects of specific heavy metal/metalloid intoxication (As, Cd, Pb, Hg, and Cu) in the small vessel associated endothelium and vascular dysfunction too have been reviewed. An attempt has been made to highlight the possible molecular mechanism involved in the pathophysiology, such as oxidative stress, inflammatory pathway, matrix metalloproteinases (MMPs) expression, and amyloid angiopathy in the CSVD and related disorders. Finally, we discussed the role of cellular antioxidant defense enzymes to neutralize the toxic effect, and also highlighted the potential reversal strategies to combat heavy metal-induced vascular changes. In conclusion, heavy metals in small vessels are strongly associated with the development as well as the progression of CSVD. Chelation therapy may be an effective strategy to reduce the toxic metal load and the associated complications.

Association between serum copper levels and prevalence of hyperuricemia: a cross-sectional study

Hyperuricemia has been recognized as a worldwide public health concern. This study was conducted to examine the association between serum copper (Cu) concentration and the prevalence of hyperuricemia in a middle-aged and elderly population. Serum Cu concentration was measured by Roche modular P800 using the PAESA method. Serum uric acid (UA) concentration was detected by a Beckman Coulter AU 5800. Presence of hyperuricemia was defined as serum UA ≥ 416 μmol/L for men and ≥360 μmol/L for women. The association between serum Cu concentration and the prevalence of hyperuricemia was evaluated by logistic regression. The prevalence of hyperuricemia was 17.6% (n = 6,212) in the present study. Relative to the lowest quintile, the age- and sex-adjusted odds ratios for hyperuricemia were 1.38 (95% CI: 1.12 to 1.70), 1.34 (95% CI: 1.07 to 1.66), and 1.53 (95% CI: 1.23 to 1.91) in the third, fourth, and fifth serum Cu concentration quintiles (P for trend < 0.001). Similar results were found both in men and women subgroups. None of the findings were materially altered after adjustment for additional potential confounders. In conclusion, in this population-based cross-sectional study, serum Cu concentration was positively associated with the prevalence of hyperuricemia.

Novel interaction of antioxidant-1 with TRAF4: role in inflammatory responses in endothelial cells

NADPH oxidase (NOX)-derived reactive oxygen species (ROS) and copper (Cu), an essential micronutrient, have been implicated in vascular inflammatory diseases. We reported that in proinflammatory cytokine TNF-α-stimulated endothelial cells (ECs), cytosolic Cu chaperone antioxidant-1 (Atox1) functions as a Cu-dependent transcription factor for the NOX organizer p47phox, thereby increasing ROS-dependent inflammatory gene expression. However, the role and mechanism of Atox1 nuclear translocation in inflamed ECs remain unclear. Using enface staining and nuclear fractionation, here we show that Atox1 was localized in the nucleus in inflamed aortas from ApoE^-/- mice with angiotensin II infusion on a high-fat diet, while it was found in cytosol in those from control mice. In cultured human ECs, TNF-α stimulation promoted Atox1 nuclear translocation within 15 min, which was associated with Atox1 binding to TNF-α receptor-associated factor 4 (TRAF4) in a Cu-dependent manner. TRAF4 depletion by siRNA significantly inhibited Atox1 nuclear translocation, p47phox expression, and ROS production as well as its downstream VCAM1/ICAM1 expression and monocyte adhesion to inflamed ECs, which were rescued by overexpression of nuclear targeted Atox1. Furthermore, Atox1 colocalized with TRAF4 at the nucleus in TNF-α-stimulated inflamed ECs and vessels. In summary, Cu-dependent Atox1 binding to TRAF4 plays an important role in Atox1 nuclear translocation and ROS-dependent inflammatory responses in TNF-α-stimulated ECs. Thus the Atox1-TRAF4 axis is a novel therapeutic target for vascular inflammatory disease such as atherosclerosis.

CuII(atsm) Attenuates Neuroinflammation

Background: Neuroinflammation and biometal dyshomeostasis are key pathological features of several neurodegenerative diseases, including Alzheimer’s disease (AD). Inflammation and biometals are linked at the molecular level through regulation of metal buffering proteins such as the metallothioneins. Even though the molecular connections between metals and inflammation have been demonstrated, little information exists on the effect of copper modulation on brain inflammation.

Methods: We demonstrate the immunomodulatory potential of the copper bis(thiosemicarbazone) complex Cu^II(atsm) in an neuroinflammatory model in vivo and describe its anti-inflammatory effects on microglia and astrocytes in vitro.

Results: By using a sophisticated in vivo magnetic resonance imaging (MRI) approach, we report the efficacy of Cu^II(atsm) in reducing acute cerebrovascular inflammation caused by peripheral administration of bacterial lipopolysaccharide (LPS). Cu^II(atsm) also induced anti-inflammatory outcomes in primary microglia [significant reductions in nitric oxide (NO), monocyte chemoattractant protein 1 (MCP-1), and tumor necrosis factor (TNF)] and astrocytes [significantly reduced NO, MCP-1, and interleukin 6 (IL-6)] in vitro. These anti-inflammatory actions were associated with increased cellular copper levels and increased the neuroprotective protein metallothionein-1 (MT1) in microglia and astrocytes.

Conclusion: The beneficial effects of Cu^II(atsm) on the neuroimmune system suggest copper complexes are potential therapeutics for the treatment of neuroinflammatory conditions.

Copper transporters and copper chaperones: roles in cardiovascular physiology and disease

Copper (Cu) is an essential micronutrient but excess Cu is potentially toxic. Its important propensity to cycle between two oxidation states accounts for its frequent presence as a cofactor in many physiological processes through Cu-containing enzymes, including mitochondrial energy production (via cytochrome c-oxidase), protection against oxidative stress (via superoxide dismutase), and extracellular matrix stability (via lysyl oxidase). Since free Cu is potentially toxic, the bioavailability of intracellular Cu is tightly controlled by Cu transporters and Cu chaperones. Recent evidence reveals that these Cu transport systems play an essential role in the physiological responses of cardiovascular cells, including cell growth, migration, angiogenesis and wound repair. In response to growth factors, cytokines, and hypoxia, their expression, subcellular localization, and function are tightly regulated. Cu transport systems and their regulators have also been linked to various cardiovascular pathophysiologies such as hypertension, inflammation, atherosclerosis, diabetes, cardiac hypertrophy, and cardiomyopathy. A greater appreciation of the central importance of Cu transporters and Cu chaperones in cell signaling and gene expression in cardiovascular biology offers the possibility of identifying new therapeutic targets for cardiovascular disease.

Tetrathiomolybdate Treatment Leads to the Suppression of Inflammatory Responses through the TRAF6/NFκB Pathway in LPS-Stimulated BV-2 Microglia

Although the positive relationship between copper and Alzheimer's disease (AD) was reported by a lot of epidemiological data, the mechanism is not completely known. Copper is a redox metal and serves as a mediator of inflammation. Because the homeostasis of copper is altered in Aβ precursor protein (APP) and presenilin 1 (PS1) transgenic (Tg) mice, the using of copper chelators is a potential therapeutic strategy for AD. Here we report that a copper chelator, tetrathiomolybdate (TM), is a potential therapeutic drug of AD. We investigated whether TM treatment led to a decrease of pro-inflammatory cytokines in vivo and in vitro, and found that TM treatment reduced the expression of iNOS and TNF-α in APP/PS1 Tg mice through up-regulating superoxide dismutase 1 (SOD1) activity. In vitro, once stimulated, microglia secretes a variety of proinflammatory cytokines, so we utilized LPS-stimulated BV-2 cells as the inflammatory cell model to detect the anti-inflammatory effects of TM. Our results indicated that TM-pretreatment suppressed the ubiquitination of TRAF6 and the activation of NFκB without affecting the expression of TLR4 and Myd88 in vitro. By detecting the activity of SOD1 and the production of reactive oxygen species (ROS), we found that the anti-inflammatory effects of TM could be attributed to its ability to reduce the amount of intracellular bioavailable copper, and the production of ROS which is an activator of the TRAF6 auto-ubiquitination. Hence, our results revealed that TM-treatment could reduce the production of inflammatory cytokines by the suppression of ROS/TRAF6/AKT/NFκB signaling pathway.

Copper toxicology, oxidative stress and inflammation using zebrafish as experimental model

Copper is an essential micronutrient and a key catalytic cofactor in a wide range of enzymes. As a trace element, copper levels are tightly regulated and both its deficit and excess are deleterious to the organism. Under inflammatory conditions, serum copper levels are increased and trigger oxidative stress responses that activate inflammatory responses. Interestingly, copper dyshomeostasis, oxidative stress and inflammation are commonly present in several chronic diseases. Copper exposure can be easily modeled in zebrafish; a consolidated model in toxicology with increasing interest in immunity-related research. As a result of developmental, economical and genetic advantages, this freshwater teleost is uniquely suitable for chemical and genetic large-scale screenings, representing a powerful experimental tool for a whole-organism approach, mechanistic studies, disease modeling and beyond. Copper toxicological and more recently pro-inflammatory effects have been investigated in both larval and adult zebrafish with breakthrough findings. Here, we provide an overview of copper metabolism in health and disease and its effects on oxidative stress and inflammation responses in zebrafish models. Copper-induced inflammation is highlighted owing to its potential to easily mimic pro-oxidative and pro-inflammatory features that combined with zebrafish genetic tractability could help further in the understanding of copper metabolism, inflammatory responses and related diseases. Copyright © 2016 John Wiley & Sons, Ltd.

Behind the Link between Copper and Angiogenesis: Established Mechanisms and an Overview on the Role of Vascular Copper Transport Systems

Angiogenesis critically sustains the progression of both physiological and pathological processes. Copper behaves as an obligatory co-factor throughout the angiogenic signalling cascades, so much so that a deficiency causes neovascularization to abate. Moreover, the progress of several angiogenic pathologies (e.g. diabetes, cardiac hypertrophy and ischaemia) can be tracked by measuring serum copper levels, which are being increasingly investigated as a useful prognostic marker. Accordingly, the therapeutic modulation of body copper has been proven effective in rescuing the pathological angiogenic dysfunctions underlying several disease states. Vascular copper transport systems profoundly influence the activation and execution of angiogenesis, acting as multi-functional regulators of apparently discrete pro-angiogenic pathways. This review concerns the complex relationship among copper-dependent angiogenic factors, copper transporters and common pathological conditions, with an unusual accent on the multi-faceted involvement of the proteins handling vascular copper. Functions regulated by the major copper transport proteins (CTR1 importer, ATP7A efflux pump and metallo-chaperones) include the modulation of endothelial migration and vascular superoxide, known to activate angiogenesis within a narrow concentration range. The potential contribution of prion protein, a controversial regulator of copper homeostasis, is discussed, even though its angiogenic involvement seems to be mainly associated with the modulation of endothelial motility and permeability.

The copper chelator tetrathiomolybdate regressed bleomycin-induced pulmonary fibrosis in mice, by reducing lysyl oxidase expressions

Pulmonary fibrosis (PF) is characterized by an increase in the number of fibroblasts and an accumulation of collagen fibers in the extracellular matrix (ECM). The members of the copper-dependent lysyl oxidase (LOX) enzyme family regulate the collagen accumulation in the ECM. Tetrathiomolybdate (TM) is a copper chelator. The present study reported the effect of TM on the expression of LOX proteins (LOX, LOXL1, and LOXL2), collagen digestion enzymes (MMP2 and MMP8), and TIMP1 (a collagenase inhibitor) in PF. The PF in mice was induced by intratracheal bleomycin instillation. Adult mice were divided into four groups: mice dissected after 21 days of the first bleomycin (0.08 mg/kg, single dose) treatment (I) and their controls (II), and mice treated with TM for 1 week (1.2 mg/day/mice for the first 4 days and 0.9 mg/day/mice for the last 3 days) after 14 days of the first bleomycin instillation and dissected in the 21st day of the experiment (III) and their controls (IV). Mice in groups III and IV were fed a low-copper (2 mg/kg) diet during the last 7 days of the experiment. The fibrosis score in the lung was determined under a microscope. The expressions of collagen-I, LOX, MMP, and TIMP1 proteins were analyzed by Western blotting in the lung. Mice lungs with fibrosis were characterized by an overexpression of collagen-I, LOX, MMP, and TIMP1 proteins in addition to an accumulation of collagen fibers. TM treatments significantly regressed the overexpression of these proteins in the fibrotic mice lung. In conclusion, TM treatments can be used for the regression of PF, by decreasing collagen-I protein expression and accumulation.