Intermittent hypoxia exacerbates metabolic dysfunction-associated fatty liver disease by aggravating hepatic copper deficiency-induced ferroptosis.

Intermittent hypoxia (IH) is an independent risk factor for metabolic dysfunction-associated fatty liver disease (MAFLD). Copper deficiency can disrupt redox homeostasis, iron, and lipid metabolism. Here, we investigated whether hepatic copper deficiency plays a role in IH-associated MAFLD and explored the underlying mechanism(s). Male C57BL/6 mice were fed a western-type diet with adequate copper (CuA) or marginally deficient copper (CuD) and were exposed separately to room air (RA) or IH. Hepatic histology, plasma biomarkers, copper-iron status, and oxidative stress were assessed. An in vitro HepG2 cell lipotoxicity model and proteomic analysis were used to elucidate the specific targets involved. We observed that there were no differences in hepatic phenotypes between CuA-fed and CuD-fed mice under RA. However, in IH exposure, CuD-fed mice showed more pronounced hepatic steatosis, liver injury, and oxidative stress than CuA-fed mice. IH induced copper accumulation in the brain and heart and exacerbated hepatic copper deficiency and secondary iron deposition. In vitro, CuD-treated cells with IH exposure showed elevated levels of lipid accumulation, oxidative stress, and ferroptosis susceptibility. Proteomic analysis identified 360 upregulated and 359 downregulated differentially expressed proteins between CuA and CuD groups under IH; these proteins were mainly enriched in citrate cycle, oxidative phosphorylation, fatty acid metabolism, the peroxisome proliferator-activated receptor (PPAR)α pathway, and ferroptosis. In IH exposure, CuD significantly upregulated the ferroptosis-promoting factor arachidonyl-CoA synthetase long chain family member (ACSL)4. ACSL4 knockdown markedly eliminated CuD-induced ferroptosis and lipid accumulation in IH exposure. In conculsion, IH can lead to reduced hepatic copper reserves and secondary iron deposition, thereby inducing ferroptosis and subsequent MAFLD progression. Insufficient dietary copper may worsen IH-associated MAFLD.

Are the elements zinc, copper, magnesium, and rubidium related to nutrition and iodine deficiency in pregnant Bulgarian women from iodine deficient region?

OBJECTIVE: Trace elements are essential for the biochemistry of the cell. Their reference values have been found to differ considerably in pregnant women stratified by age, place of residence, anthropometric status, and length of pregnancy. In optimal amounts, these elements reduce the risk of pregnancy complications. Subclinical hypothyroidism in pregnancy is associated with adverse maternal and neonatal outcomes. The aim of the study was to determine the effects of zinc (Zn), copper (Cu), magnesium (Mg), and rubidium (Rb) on pregnant women in an iodine deficiency region and find the relationship with the thyroid status and nutrition. METHODS: We evaluated the iodine status of 61 healthy pregnant women from an iodine deficient region in Bulgaria. Thyroid stimulating hormone (TSH) and thyroxin free (FT4) levels were measured using ELISA. RESULTS: We found elevated levels of copper that differed the most between the first and second trimesters; Cu and TSH were found to be positively correlated (р < 0.05). Lower Cu levels were found in pregnant women consuming pulses more than 2-3 times a week (р = 0.033). The women consuming fish more than 2-3 times a week had higher levels of Rb. We found a pronounced iodine deficiency in more than half of the examined women in the first to third trimesters, without any effect of pregnancy on the ioduria (р=0.834). All second and third trimester cases were associated with severe ioduria (< 150 µg/L). CONCLUSION: The high Cu levels were associated with subclinical hypothyroidism (SCH) and less pulse consumption during pregnancy in an iodine deficiency endemic area. SCH was found in 24% of the pregnant women in such an area while in 13% of them SCH had progressed to overt hypothyroidism.

Inactivation of cytosolic FUMARASE2 enhances growth and photosynthesis under simultaneous copper and iron deprivation in Arabidopsis.

Copper (Cu) and iron (Fe) are essential for plant growth and are often in short supply under natural conditions. Molecular responses to simultaneous lack of both metals (-Cu-Fe) differ from those seen in the absence of either alone. Metabolome profiling of plant leaves previously revealed that fumarate levels fall under -Cu-Fe conditions. We employed lines lacking cytosolic FUMARASE2 (FUM2) activity to study the impact of constitutive suppression of cytosolic fumarate synthesis on plant growth under Cu and/or Fe deficiency. In fum2 mutants, photosynthesis and growth were less impaired under -Cu-Fe conditions than in wild-type (WT) seedlings. In particular, levels of photosynthetic proteins, chloroplast ultrastructure, amino acid profiles and redox state were less perturbed by simultaneous Cu-Fe deficiency in lines that cannot produce fumarate in the cytosol. Although cytosolic fumarate has been reported to promote acclimation of photosynthesis to low temperatures when metal supplies are adequate, the photosynthetic efficiency of fum2 lines grown under Cu-Fe deficiency in the cold was higher than in WT. Uptake and contents of Cu and Fe are similar in WT and fum2 plants under control and -Cu-Fe conditions, and lack of FUM2 does not alter the ability to sense metal deficiency, as indicated by marker gene expression. Collectively, we propose that reduced levels of cytosolic fumarate synthesis ultimately increase the availability of Fe for incorporation into metalloproteins.

ASCORBATE PEROXIDASE6 delays the onset of age-dependent leaf senescence.

Age-dependent changes in reactive oxygen species (ROS) levels are critical in leaf senescence. While H2O2-reducing enzymes such as catalases and cytosolic ASCORBATE PEROXIDASE1 (APX1) tightly control the oxidative load during senescence, their regulation and function are not specific to senescence. Previously, we identified the role of ASCORBATE PEROXIDASE6 (APX6) during seed maturation in Arabidopsis (Arabidopsis thaliana). Here, we show that APX6 is a bona fide senescence-associated gene. APX6 expression is specifically induced in aging leaves and in response to senescence-promoting stimuli such as abscisic acid (ABA), extended darkness, and osmotic stress. apx6 mutants showed early developmental senescence and increased sensitivity to dark stress. Reduced APX activity, increased H2O2 level, and altered redox state of the ascorbate pool in mature pre-senescing green leaves of the apx6 mutants correlated with the early onset of senescence. Using transient expression assays in Nicotiana benthamiana leaves, we unraveled the age-dependent post-transcriptional regulation of APX6. We then identified the coding sequence of APX6 as a potential target of miR398, which is a key regulator of copper redistribution. Furthermore, we showed that mutants of SQUAMOSA PROMOTER BINDING PROTEIN-LIKE7 (SPL7), the master regulator of copper homeostasis and miR398 expression, have a higher APX6 level compared with the wild type, which further increased under copper deficiency. Our study suggests that APX6 is a modulator of ROS/redox homeostasis and signaling in aging leaves that plays an important role in developmental- and stress-induced senescence programs.

Systems biology of responses to simultaneous copper and iron deficiency in Arabidopsis.

Plant responses to coincident nutrient deficiencies cannot be predicted from the responses to individual deficiencies. Although copper (Cu) and iron (Fe) are essential micronutrients for plant growth that are often and concurrently limited in soils, the combinatorial response to Cu-Fe deficiency remains elusive. In the present study, we characterised the responses of Arabidopsis thaliana plants deprived of Cu, Fe or both (-Cu-Fe) at the level of plant development, mineral composition, and reconfiguration of transcriptomes, proteomes and metabolomes. Compared to single deficiencies, simultaneous -Cu-Fe leads to a distinct pattern in leaf physiology and microelement concentration characterised by lowered protein content and enhanced manganese and zinc levels. Conditional networking analysis of molecular changes indicates that biological processes also display different co-expression patterns among single and double deficiencies. Indeed, the interaction between Cu and Fe deficiencies causes distinct expression profiles for 15% of all biomolecules, leading to specific enhancement of general stress responses and protein homeostasis mechanisms, at the same time as severely arresting photosynthesis. Accordingly, central carbon metabolites, in particular photosynthates, decrease especially under -Cu-Fe conditions, whereas the pool of free amino acids increases. Further meta-analysis of transcriptomes and proteomes corroborated that protein biosynthesis and folding capacity were readjusted during the combinatorial response and unveiled important rearrangements in the metabolism of organic acids. Consequently, our results demonstrate that the response to -Cu-Fe imposes a distinct reconfiguration of large sets of molecules, not triggered by single deficiencies, resulting into a switch from autotrophy to heterotrophy and involving organic acids such as fumaric acid as central mediators of the response.

Copper-dependent amino oxidase 3 governs selection of metabolic fuels in adipocytes.

Copper (Cu) has emerged as an important modifier of body lipid metabolism. However, how Cu contributes to the physiology of fat cells remains largely unknown. We found that adipocytes require Cu to establish a balance between main metabolic fuels. Differentiating adipocytes increase their Cu uptake along with the ATP7A-dependent transport of Cu into the secretory pathway to activate a highly up-regulated amino-oxidase copper-containing 3 (AOC3)/semicarbazide-sensitive amine oxidase (SSAO); in vivo, the activity of SSAO depends on the organism's Cu status. Activated SSAO oppositely regulates uptake of glucose and long-chain fatty acids and remodels the cellular proteome to coordinate changes in fuel availability and related downstream processes, such as glycolysis, de novo lipogenesis, and sphingomyelin/ceramide synthesis. The loss of SSAO-dependent regulation due to Cu deficiency, limited Cu transport to the secretory pathway, or SSAO inactivation shifts metabolism towards lipid-dependent pathways and results in adipocyte hypertrophy and fat accumulation. The results establish a role for Cu homeostasis in adipocyte metabolism and identify SSAO as a regulator of energy utilization processes in adipocytes.

Elesclomol restores mitochondrial function in genetic models of copper deficiency.

Copper is an essential cofactor of cytochrome c oxidase (CcO), the terminal enzyme of the mitochondrial respiratory chain. Inherited loss-of-function mutations in several genes encoding proteins required for copper delivery to CcO result in diminished CcO activity and severe pathologic conditions in affected infants. Copper supplementation restores CcO function in patient cells with mutations in two of these genes, COA6 and SCO2, suggesting a potential therapeutic approach. However, direct copper supplementation has not been therapeutically effective in human patients, underscoring the need to identify highly efficient copper transporting pharmacological agents. By using a candidate-based approach, we identified an investigational anticancer drug, elesclomol (ES), that rescues respiratory defects of COA6-deficient yeast cells by increasing mitochondrial copper content and restoring CcO activity. ES also rescues respiratory defects in other yeast mutants of copper metabolism, suggesting a broader applicability. Low nanomolar concentrations of ES reinstate copper-containing subunits of CcO in a zebrafish model of copper deficiency and in a series of copper-deficient mammalian cells, including those derived from a patient with SCO2 mutations. These findings reveal that ES can restore intracellular copper homeostasis by mimicking the function of missing transporters and chaperones of copper, and may have potential in treating human disorders of copper metabolism.

Comparison of the one-year outcomes of bariatric surgery in adolescents and young adults: a matched case-control study, Tehran Obesity Treatment Study (TOTS).

PURPOSES: The increasing use of bariatric surgery in adolescents has raised some concerns regarding the postoperative outcomes and the optimal time of surgery at young ages. However, no study has yet compared the weight loss and comorbidity resolution following bariatric surgery between adolescents and young adults. METHODS: This study was conducted on a case group of adolescents (aged 11-18) and a control group of young adults (aged 19-29) undergoing bariatric surgery (sleeve gastrectomy or gastric bypass). The two groups were matched in terms of gender, body mass index (BMI), and surgery type and were assessed regarding the surgical outcomes at 1 year after surgery. RESULTS: The baseline characteristics of the adolescents (n = 118, mean age: 17.0 ± 1.6 years) and young adults (n = 236, mean age: 25.2 ± 3.2 years) were similar, as well as surgery-associated complications. The mean loss of BMI (- 15.4 ± 3.6 vs. -15.8 ± 4.6 kg/m2) and 12-month percentage of excess weight loss (80.4 ± 20.1 vs. 80.2 ± 20.1%) were similar in the two groups. Both groups showed parallel reductions in the cardiovascular risk factors. The remission of hypertension, diabetes mellitus, and dyslipidemia was similar between the groups. The increase in the hemoglobin level and copper deficiency was greater in young adults, whereas the increase in ferritin deficiency was greater in adolescents. CONCLUSION: Similar to young adults, bariatric surgery is an effective and safe method to achieve weight loss, resolve obesity-related comorbidities, and improve cardiovascular risk factors in the adolescents.

The molecular mechanisms of copper metabolism and its roles in human diseases.

Copper is an essential element in cells; it can act as either a recipient or a donor of electrons, participating in various reactions. However, an excess of copper ions in cells is detrimental as these copper ions can generate free radicals and increase oxidative stress. In multicellular organisms, copper metabolism involves uptake, distribution, sequestration, and excretion, at both the cellular and systemic levels. Mammalian enterocytes take in bioavailable copper ions from the diet in a Ctr1-dependent manner. After incorporation, cuprous ions are delivered to ATP7A, which pumps Cu+ from enterocytes into the blood. Copper ions arrive at the liver through the portal vein and are incorporated into hepatocytes by Ctr1. Then, Cu+ can be secreted into the bile or the blood via the Atox1/ATP7B/ceruloplasmin route. In the bloodstream, this micronutrient can reach peripheral tissues and is again incorporated by Ctr1. In peripheral tissue cells, cuprous ions are either sequestrated by molecules such as metallothioneins or targeted to utilization pathways by chaperons such as Atox1, Cox17, and CCS. Copper metabolism must be tightly controlled in order to achieve homeostasis and avoid disorders. A hereditary or acquired copper unbalance, including deficiency, overload, or misdistribution, may cause or aggravate certain diseases such as Menkes disease, Wilson disease, neurodegenerative diseases, anemia, metabolic syndrome, cardiovascular diseases, and cancer. A full understanding of copper metabolism and its roles in diseases underlies the identification of novel effective therapies for such diseases.

Arabidopsis Pollen Fertility Requires the Transcription Factors CITF1 and SPL7 That Regulate Copper Delivery to Anthers and Jasmonic Acid Synthesis.

A deficiency of the micronutrient copper (Cu) leads to infertility and grain/seed yield reduction in plants. How Cu affects fertility, which reproductive structures require Cu, and which transcriptional networks coordinate Cu delivery to reproductive organs is poorly understood. Using RNA-seq analysis, we showed that the expression of a gene encoding a novel transcription factor, CITF1 (Cu-DEFICIENCY INDUCED TRANSCRIPTION FACTOR1), was strongly upregulated in Arabidopsis thaliana flowers subjected to Cu deficiency. We demonstrated that CITF1 regulates Cu uptake into roots and delivery to flowers and is required for normal plant growth under Cu deficiency. CITF1 acts together with a master regulator of copper homeostasis, SPL7 (SQUAMOSA PROMOTER BINDING PROTEIN LIKE7), and the function of both is required for Cu delivery to anthers and pollen fertility. We also found that Cu deficiency upregulates the expression of jasmonic acid (JA) biosynthetic genes in flowers and increases endogenous JA accumulation in leaves. These effects are controlled in part by CITF1 and SPL7. Finally, we show that JA regulates CITF1 expression and that the JA biosynthetic mutant lacking the CITF1- and SPL7-regulated genes, LOX3 and LOX4, is sensitive to Cu deficiency. Together, our data show that CITF1 and SPL7 regulate Cu uptake and delivery to anthers, thereby influencing fertility, and highlight the relationship between Cu homeostasis, CITF1, SPL7, and the JA metabolic pathway.

Wilson disease: copper deficiency and iatrogenic neurological complications with zinc therapy.

A 17-year-old female was diagnosed with Wilson disease and commenced on oral zinc therapy. She re-presented 6 months later with a fall and had classical signs of subacute combined degeneration of the spinal cord confirmed on nerve conduction studies, as a result of zinc-induced copper deficiency. After 6 months of copper therapy, she made a complete recovery with no residual neurological deficits. Early detection of zinc-induced copper deficiency and stringent follow-up mechanisms are crucial. Early initiation of copper replacement may both limit and completely reverse neurological deficits.

The Role of Zinc in Copper Homeostasis of Aspergillus fumigatus.

Copper is an essential metal ion that performs many physiological functions in living organisms. Deletion of Afmac1, which is a copper-responsive transcriptional activator in A. fumigatus, results in a growth defect on aspergillus minimal medium (AMM). Interestingly, we found that zinc starvation suppressed the growth defect of the Δafmac1 strain on AMM. In addition, the growth defect of the Δafmac1 strain was recovered by copper supplementation or introduction of the CtrC gene into the Δafmac1 strain. However, chelation of copper by addition of BCS to AMM failed to recover the growth defect of the Δafmac1 strain. Through Northern blot analysis, we found that zinc starvation upregulated CtrC and CtrA2, which encode membrane copper transporters. Interestingly, we found that the conserved ZafA binding motif 5'-CAA(G)GGT-3' was present in the upstream region of CtrC and CtrA2 and that mutation of the binding motif led to failure of ZafA binding to the upstream region of CtrC and upregulation of CtrC expression under zinc starvation. Furthermore, the binding activity of ZafA to the upstream region of CtrC was inversely proportional to the zinc concentration, and copper inhibited the binding of ZafA to the upstream region of CtrC under a low zinc concentration. Taken together, these results suggest that ZafA upregulates copper metabolism by binding to the ZafA binding motif in the CtrC promoter region under low zinc concentration, thus regulating copper homeostasis. Furthermore, we found that copper and zinc interact in cells to maintain metal homeostasis.

Copper Dyshomeostasis in Neurodegenerative Diseases-Therapeutic Implications.

Copper is one of the most abundant basic transition metals in the human body. It takes part in oxygen metabolism, collagen synthesis, and skin pigmentation, maintaining the integrity of blood vessels, as well as in iron homeostasis, antioxidant defense, and neurotransmitter synthesis. It may also be involved in cell signaling and may participate in modulation of membrane receptor-ligand interactions, control of kinase and related phosphatase functions, as well as many cellular pathways. Its role is also important in controlling gene expression in the nucleus. In the nervous system in particular, copper is involved in myelination, and by modulating synaptic activity as well as excitotoxic cell death and signaling cascades induced by neurotrophic factors, copper is important for various neuronal functions. Current data suggest that both excess copper levels and copper deficiency can be harmful, and careful homeostatic control is important. This knowledge opens up an important new area for potential therapeutic interventions based on copper supplementation or removal in neurodegenerative diseases including Wilson's disease (WD), Menkes disease (MD), Alzheimer's disease (AD), Parkinson's disease (PD), and others. However, much remains to be discovered, in particular, how to regulate copper homeostasis to prevent neurodegeneration, when to chelate copper, and when to supplement it.

A Case of Copper Deficiency Myeloneuropathy Precipitated by Zinc Ingestion and Bariatric Surgery.

In this report, we present a case of acquired copper deficiency which initially presented as progressive pain and numbness in the patient's lower extremities. The acquired copper deficiency is attributed to a previous bariatric surgery exacerbated by zinc toxicity. A 42-year-old female with a past medical history of type 2 diabetes mellitus, anemia, hypertension, bipolar disorder, attention deficit disorder, pulmonary embolus, fibromyalgia, migraine headaches, and chronic pain as well as a remote past surgical history of gastric bypass procedure presented with progressive pain and numbness in her lower extremities. The patient reported chronic use of zinc supplements. Clinical evaluation revealed abnormal neurologic exam consistent with a myeloneuropathy and anemia. A cervical spine MRI showed increased signal intensity primarily affecting the posterior columns from C2-C6. Laboratory studies confirmed low copper, low ceruloplasmin, and elevated zinc levels. This case is an example of acquired copper deficiency due to previous bariatric surgery exacerbated by zinc ingestion. With an increased prevalence of bariatric surgery, it is important to monitor patients postoperatively for neurologic symptoms potentially due to copper deficiency.

The mitochondrial metallochaperone SCO1 maintains CTR1 at the plasma membrane to preserve copper homeostasis in the murine heart.

SCO1 is a ubiquitously expressed, mitochondrial protein with essential roles in cytochrome c oxidase (COX) assembly and the regulation of copper homeostasis. SCO1 patients present with severe forms of early onset disease, and ultimately succumb from liver, heart or brain failure. However, the inherent susceptibility of these tissues to SCO1 mutations and the clinical heterogeneity observed across SCO1 pedigrees remain poorly understood phenomena. To further address this issue, we generated Sco1hrt/hrt and Sco1stm/stm mice in which Sco1 was specifically deleted in heart and striated muscle, respectively. Lethality was observed in both models due to a combined COX and copper deficiency that resulted in a dilated cardiomyopathy. Left ventricular dilation and loss of heart function was preceded by a temporal decrease in COX activity and copper levels in the longer-lived Sco1stm/stm mice. Interestingly, the reduction in copper content of Sco1stm/stm cardiomyocytes was due to the mislocalisation of CTR1, the high affinity transporter that imports copper into the cell. CTR1 was similarly mislocalized to the cytosol in the heart of knockin mice carrying a homozygous G115S substitution in Sco1, which in humans causes a hypertrophic cardiomyopathy. Our current findings in the heart are in marked contrast to our prior observations in the liver, where Sco1 deletion results in a near complete absence of CTR1 protein. These data collectively argue that mutations perturbing SCO1 function have tissue-specific consequences for the machinery that ultimately governs copper homeostasis, and further establish the importance of aberrant mitochondrial signaling to the etiology of copper handling disorders.

Copper Regulates Maturation and Expression of an MITF:Tryptase Axis in Mast Cells.

Copper has previously been implicated in the regulation of immune responses, but the impact of this metal on mast cells is poorly understood. In this article, we address this issue and show that copper starvation of mast cells causes increased granule maturation, as indicated by higher proteoglycan content, stronger metachromatic staining, and altered ultrastructure in comparison with nontreated cells, whereas copper overload has the opposite effects. In contrast, copper status did not impact storage of histamine in mast cells, nor did alterations in copper levels affect the ability of mast cells to degranulate in response to IgER cross-linking. A striking finding was decreased tryptase content in mast cells with copper overload, whereas copper starvation increased tryptase content. These effects were associated with corresponding shifts in tryptase mRNA levels, suggesting that copper affects tryptase gene regulation. Mechanistically, we found that alterations in copper status affected the expression of microphthalmia-associated transcription factor, a transcription factor critical for driving tryptase expression. We also found evidence supporting the concept that the effects on microphthalmia-associated transcription factor are dependent on copper-mediated modulation of MAPK signaling. Finally, we show that, in MEDNIK syndrome, a condition associated with low copper levels and a hyperallergenic skin phenotype, including pruritis and dermatitis, the number of tryptase-positive mast cells is increased. Taken together, our findings reveal a hitherto unrecognized role for copper in the regulation of mast cell gene expression and maturation.

SCO2 mutations cause early-onset axonal Charcot-Marie-Tooth disease associated with cellular copper deficiency.

Recessive mutations in the mitochondrial copper-binding protein SCO2, cytochrome c oxidase (COX) assembly protein, have been reported in several cases with fatal infantile cardioencephalomyopathy with COX deficiency. Significantly expanding the known phenotypic spectrum, we identified compound heterozygous variants in SCO2 in two unrelated patients with axonal polyneuropathy, also known as Charcot-Marie-Tooth disease type 4. Different from previously described cases, our patients developed predominantly motor neuropathy, they survived infancy, and they have not yet developed the cardiomyopathy that causes death in early infancy in reported patients. Both of our patients harbour missense mutations near the conserved copper-binding motif (CXXXC), including the common pathogenic variant E140K and a novel change D135G. In addition, each patient carries a second mutation located at the same loop region, resulting in compound heterozygote changes E140K/P169T and D135G/R171Q. Patient fibroblasts showed reduced levels of SCO2, decreased copper levels and COX deficiency. Given that another Charcot-Marie-Tooth disease gene, ATP7A, is a known copper transporter, our findings further underline the relevance of copper metabolism in Charcot-Marie-Tooth disease.

In vivo bioluminescence imaging reveals copper deficiency in a murine model of nonalcoholic fatty liver disease.

Copper is a required metal nutrient for life, but global or local alterations in its homeostasis are linked to diseases spanning genetic and metabolic disorders to cancer and neurodegeneration. Technologies that enable longitudinal in vivo monitoring of dynamic copper pools can help meet the need to study the complex interplay between copper status, health, and disease in the same living organism over time. Here, we present the synthesis, characterization, and in vivo imaging applications of Copper-Caged Luciferin-1 (CCL-1), a bioluminescent reporter for tissue-specific copper visualization in living animals. CCL-1 uses a selective copper(I)-dependent oxidative cleavage reaction to release d-luciferin for subsequent bioluminescent reaction with firefly luciferase. The probe can detect physiological changes in labile Cu+ levels in live cells and mice under situations of copper deficiency or overload. Application of CCL-1 to mice with liver-specific luciferase expression in a diet-induced model of nonalcoholic fatty liver disease reveals onset of hepatic copper deficiency and altered expression levels of central copper trafficking proteins that accompany symptoms of glucose intolerance and weight gain. The data connect copper dysregulation to metabolic liver disease and provide a starting point for expanding the toolbox of reactivity-based chemical reporters for cell- and tissue-specific in vivo imaging.

The effect of copper nanoparticles and copper (II) salt on redox reactions and epigenetic changes in a rat model.

The aim of the study was to evaluate the effects of a diet containing different levels of Cu in two different chemical forms (carbonate and nanoparticles) on redox reactions and epigenetic changes in a rat model. For 4 weeks, five experimental groups (eight rats in each) were fed diets with two dosages of added Cu (standard-6.5 mg/kg or half of the standard dosage-3.25 mg/kg, and as a negative control no additional Cu in the mineral mixture) in two forms (standard-CuCO3 and copper nanoparticles). Addition of Cu nanoparticles resulted in higher Cp (ceruloplasmin) activity and LOOH (lipid peroxides) and MDA (malondialdehyde) content, as well as decrease the CAT (catalase) activity and level of PC (protein carbonyl), 3-NT (3-nitrotyrosine), 8-OHdG (8-hydroxydeoxyguanosine), GSH + GSSG (total glutathione) and DNA methylation. Reducing the dose of copper resulted in a decrease in the level of LOOH and GSH + GSSG as well as CAT activity, but increased the level of PC and methylated DNA. Based on these evidence, we concluded that addition of copper nanoparticles in the diet reduces protein oxidation and nitration as well as DNA oxidation and methylation. Lowering the level of Cu in the diet increases the oxidation of proteins and DNA methylation.