Copper deficiency alters isomyosin types and levels of laminin, fibronectin and cytochrome c oxidase subunits from rat hearts

Uncovering proteome variations and concomitant quality changes of differently drying-treated rape (Brassica napus) bee pollen by label-free quantitative proteomics

High moisture content of fresh bee pollen makes it difficult to preserve and thus makes drying a necessary process during the bee pollen production. Drying treatment will affect its quality and the effects of sun drying, hot-air drying and freeze drying on the proteome of rape (Brassica napus) bee pollen have been evaluated using label-free quantitative proteomics by liquid chromatography-tandem mass spectrometer (LC-MS/MS). A total of 8377 proteins are identified, among which the most abundant differential proteins were found in freeze drying-treated samples. Also freeze-drying treatment maximizes the content of antioxidant, antibacterial and anemic bioactive pollen protein. Besides, rape bee pollen is found to adjust its metabolism to protect itself during the drying process. These results can be favorable to evaluate the effects of drying treatment on the nutrition and function of processed rape bee pollen and insight into how rape bee pollen proteins respond to dehydration.

Perspectives on the Role and Relevance of Copper in Cardiac Disease

Cardiac hypertrophy as a result of dietary copper deficiency has been studied for 40 plus years and is the subject of this review. While connective tissue anomalies occur, a hallmark pathology is cardiac hypertrophy, increased mitochondrial biogenesis, with disruptive cristae, vacuolization of mitochondria, and deposition of lipid droplets. Electrocardiogram abnormalities have been demonstrated along with biochemical changes especially as it relates to the copper-containing enzyme cytochrome c oxidase. The master controller of mitochondrial biogenesis, PGC1-α expression and protein, along with other proteins and transcriptional factors that play a role are upregulated. Nitric oxide, vascular endothelial growth factor, and cytochrome c oxidase all may enhance the upregulation of mitochondrial biogenesis. Marginal copper intakes reveal similar pathologies in the absence of cardiac hypertrophy. Reversibility of the copper-deficient rat heart with a copper-replete diet has resulted in mixed results, depending on both the animal model used and temporal relationships. New information has revealed that copper supplementation may rescue cardiac hypertrophy induced by pressure overload.

Dietary Copper Restriction-Induced Changes in Myocardial Gene Expression and the Effect of Copper Repletion

Dietary copper (Cu) restriction leads to cardiac hypertrophy and failure in mice, and Cu repletion (CuR) reverses the hypertrophy and prevents the transition to heart failure. The present study was undertaken to determine changes in myocardial gene expression involved in Cu deficient (CuD) cardiomyopathy and its reversal by CuR. Analysis was performed on three groups of mice: 4-week-old CuD mice that exhibited signs of cardiac failure, their age-matched copper-adequate (CuA) controls, and the CuD mice that were re-fed adequate Cu for 2 weeks. Total RNA was isolated from hearts and subjected to cDNA microarray and real-time reverse transcription-polymerase chain reaction analysis. Dietary CuD caused a decrease in cardiac mRNA of β-MHC, L-type Ca2+ channel, K-dependent NCX, MMP-2, -8, and -13, NF-κB, and VEGF. The mRNA levels of ET-1, TGF-β, TNF-α, and procollagen-l-α1 and III-α1 were increased in the CuD cardiac tissue. Copper repletion resulted in cardiac mRNA levels of most of the genes examined returning to control levels, although the K-dependent NCX and MMP-2 values did not reach those of the CuA control. In addition, CuR caused an increase in β-MHC, L-type Ca2+channel, MMP-13 to levels surpassing those of CuA control, and a decrease in ET-1, and TNF-at mRNA levels. In summary, changes in gene expression of elements involved in contractility, Ca2+ cycling, and inflammation and fibrosis may account for the altered cardiac function found in CuD mice. The return to normal cardiac function by CuR may be a result of the favorable regression in gene expression of these critical components in myocardial tissue.

Biomarkers assessment in the peacock blenny Salaria pavo exposed to cadmium

Cadmium (Cd) is one of the most toxic metals and is widely distributed in freshwater and marine environments. It has received much attention from a toxicological perspective. The aim of this study was to assess the effect of Cd in the peacock blenny Salaria pavo, a species of the family of blennies that was used as bioindicator of water pollution. We performed a sublethal contamination of fish to 2 mg CdCl2 L(-1) during 1, 4, 10, and 15 days. Cd accumulation was measured in gills and liver and displayed a significant increase of its concentration throughout the experiment, with slightly higher levels in the liver, except after 4 days. Partial-length cDNA of mt1, mt2, mnsod, cuznsod, cat, and gpx were characterized. Results from mRNA expression levels displayed an up-regulation of mt2 and mnsod. Biomarker activities were determined in gills and liver. In gills, data displayed an inhibition of EROD and GST activities. Cd exposure significantly increased GPx activities but did not affect CAT levels throughout the experiment. No LPO induction was observed in gills of exposed fish. Regarding the liver, the activity of all enzymes and MDA levels increased significantly from the beginning of the experiment except EROD that increased after 15 days of contamination only. At the histological level, fish exhibited pathological symptoms in gills and liver with a predominance of circulatory disturbances in gills and regressive changes in the liver. Our results displayed that peacock blennies are able to survive Cd toxicity due to various physiological adaptation mechanisms.

Homocysteine restricts copper availability leading to suppression of cytochrome C oxidase activity in phenylephrine-treated cardiomyocytes

Cardiomyocyte hypertrophy induced by phenylephrine (PE) is accompanied by suppression of cytochrome c oxidase (CCO) activity, and copper (Cu) supplementation restores CCO activity and reverses the hypertrophy. The present study was aimed to understand the mechanism of PE-induced decrease in CCO activity. Primary cultures of neonatal rat cardiomyocytes were treated with PE at a final concentration of l00 µM in cultures for 72 h to induce cell hypertrophy. The CCO activity was determined by enzymatic assay and changes in CCO subunit COX-IV as well as copper chaperones for CCO (COX17, SCO2, and COX11) were determined by Western blotting. PE treatment increased both intracellular and extracellular homocysteine concentrations and decreased intracellular Cu concentrations. Studies in vitro found that homocysteine and Cu form complexes. Inhibition of the intracellular homocysteine synthesis in the PE-treated cardiomyocytes prevented the increase in the extracellular homocysteine concentration, retained the intracellular Cu concentration, and preserved the CCO activity. PE treatment decreased protein concentrations of the COX-IV, and the Cu chaperones COX17, COX11, and SCO2. These PE effects were prevented by either inhibition of the intracellular homocysteine synthesis or Cu supplementation. Therefore, PE-induced elevation of homocysteine restricts Cu availability through its interaction with Cu and suppression of Cu chaperones, leading to the decrease in CCO enzyme activity.

The cardiac copper chaperone proteins Sco1 and CCS are up-regulated, but Cox 1 and Cox4 are down-regulated, by copper deficiency

Copper is ferried in a cell complexed to chaperone proteins, and in the heart much copper is required for cytochrome c oxidase (Cox). It is not completely understood how copper status affects the levels of these proteins. Here we determined if dietary copper deficiency could up- or down-regulate select copper chaperone proteins and Cox subunits 1 and 4 in cardiac tissue of rats. Sixteen weanling male Long-Evans rats were randomized into treatment groups, one group receiving a copper-deficient diet (<1 mg Cu/kg diet) and one group receiving a diet containing adequate copper (6 mg Cu/kg diet) for 5 weeks. Hearts were removed, weighed, and non-myofibrillar proteins separated to analyze for levels of CCS, Sco1, Ctr1, Cox17, Cox1, and Cox4 by SDS-PAGE and Western blotting. No changes were observed in the concentrations of CTR1 and Cox17 between copper-adequate and copper-deficient rats. CCS and Sco1 were up-regulated and Cox1 and Cox4 were both down-regulated as a result of copper deficiency. These data suggest that select chaperone proteins and may be up-regulated, and Cox1 and 4 down-regulated, by a dietary copper deficiency, whereas others appear not to be affected by copper status.

Mitochondrial and sarcoplasmic protein changes in hearts from copper-deficient rats: up-regulation of PGC-1alpha transcript and protein as a cause for mitochondrial biogenesis in copper deficiency

Changes in mitochondrial and sarcoplasmic proteins using proteinomics and Western blotting in hearts from copper-deficient rats were explored in this study. Also, key enzymes that are involved in cardiac energy metabolism via glycolysis and fatty acid oxidation and related transcription factors were determined. Rats were fed one of two diets: a copper-adequate diet containing 6 mg Cu/kg diet or a diet with less than 1 mg Cu/kg diet for 5 weeks. Copper deficiency was confirmed by low liver copper levels, decreased hematocrit levels and cardiac hypertrophy. Proteinomic data revealed that of the more than 50 proteins identified from the mitochondrial fraction of heart tissue, six were significantly down-regulated and nine were up-regulated. The proteins that were decreased were beta enolase 3, carbonic anhydrase 2, aldose reductase 1, glutathione peroxidase, muscle creatine kinase and mitochondrial aconitase 2. The proteins that were up-regulated were isocitrate dehydrogenase, dihydrolipoamide dehydrogenase, transferrin, subunit d of ATP synthase, transthyretin, preproapolipoprotein A-1, GRP 75, alpha-B crystalline and heat shock protein alpha. Follow-up Western blots on rate-limiting enzymes in glycolysis (phosphofructose kinase), fatty acid oxidation (medium chain acyl dehydrogenase, peroxisome proliferator-actvator receptor-alpha or PPARalpha) and gluconeogenesis (phosphoenolpyruvate carboxykinase) did not reveal changes in metabolic enzymes. However, a significant increase in peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1alpha protein, as well as the transcript, which increased 2.5-fold, was observed. It would appear that increased mitochondrial biogenesis known to occur in copper deficiency hearts is caused by an increased expression in the master regulator of mitochondrial biogenesis, PGC-1alpha.

Differential expression of genes involved with apoptosis, cell cycle, connective tissue proteins, fuel substrate utilization, inflammation and mitochondrial biogenesis in copper-deficient rat hearts: implication of a role for Nfkappab1

We hypothesized that the increase in mitochondrial proliferation in hearts from copper-deficient rats is due to an increase in expression of the transcriptional factor peroxisomal-like proliferating related coactivator 1alpha (Ppargc1a), which regulates transcriptional activity for many of the genes that encode for mitochondrial proteins. In addition to several transcriptional factors implicated in mitochondrial biogenesis, we also looked at a number of genes involved in cell cycle regulation and fuel substrate utilization. Long-Evans rats were placed on either a copper-adequate (n=4) or copper-deficient (n=4) diet 3 days post weaning and remained on the diet for 5 weeks; their copper deficiency status was confirmed using previously established assays. Custom oligo arrays spotted with genes pertinent to mitochondrial biogenesis were hybridized with cRNA probes synthesized from the collected heart tissue. Chemiluminescent array images from both groups were analyzed for gene spot intensities and differential gene expression. Our results did not demonstrate any significant increase in Ppargc1a or its implicated targets, as we had predicted. However, consistent with previous data, an up-regulation of genes that encode for collagen type 3, fibronectin and elastin were found. Interestingly, there was also a significant increase in the expression of the transcriptional factor nuclear factor kappaB1 (Nfkappab1) in the copper-deficient treatment animals, compared to the control group, and this was confirmed by real time quantitative polymerase chain reaction. The results of this study merit the further investigation of the role of reactive oxidative species with regard to Nfkappab1 in the copper deficient rat heart.

Cadmium-dependent enzyme activity alteration is not imputable to lipid peroxidation

The effect of cadmium on the liver-specific activities of NADPH-cytochrome P450 reductase (CPR), malic dehydrogenase (MDH), glyceraldehyde-3-phosphate dehydrogenase (GADPH), and sorbitol dehydrogenase (SDH) was assessed 6, 24, and 48 h after administration of the metal to rats (2.5 mg/kg of body weight, as CdCl2, single ip injection). CPR specific activity increased after 6 h and afterward decreased significantly, while MDH specific activity increased up to 24 h and then remained unchanged. Both SDH and GADPH specific activities reduced after 6 h, the former only a little but the latter much more, and after 24 and 48 h were strongly inhibited. In vitro experiments, by incubating rat liver microsomes, mitochondria, or cytosol with CdCl2 in the pH range 6.0-8.0, excluded cadmium-induced lipid peroxidation as the cause of the reduction in enzyme activity. In addition, from these experiments, we obtained indications on the type of interactions between cadmium and the enzymes studied. In the case of CPR, the inhibitory effect is probably due to Cd2+ binding to the histidine residue of the apoenzyme, which, at physiological pH, acts as a nucleophilic group. In vitro, mitochondrial MDH was not significantly affected by cadmium at any pH, indicating that this enzyme is probably not involved in the decrease in mitochondrial respiration caused by this metal. As for GADPH specific activity, its inhibition at pH 7.4 and above is imputable to the binding of cadmium to the SH groups present in the enzyme active site, since in the presence of dithiothreitol this inhibition was removed. SDH was subjected to a dual effect when cytosol was exposed to cadmium. At pH 6.0 and 6.5, its activity was strongly stimulated up to 75 microM CdCl2 while at higher metal concentrations it was reduced. At pH 7.4 and 8.0, a stimulation up to 50 microM CdCl2 occurred but above this concentration, a reduction was found. These data seem to indicate that cadmium can bind to different enzyme sites. One, at low cadmium concentration, stimulates the SDH activity while the other, at higher metal concentrations, substitutes for zinc, thus causing inhibition. This last possibility seems to occur in vivo essentially at least 24 h after intoxication. The cadmium-induced alterations of the investigated enzymes are discussed in terms of the metabolic disorders produced which are responsible for several pathological conditions.

Rat embryos cultured under copper-deficient conditions develop abnormally and are characterized by an impaired oxidant defense system

Rat embryos (gestation days 9.0 and 10.0) obtained from dams that were fed a Cu-adequate (8 micrograms Cu/g) or Cu-deficient (< 0.5 micrograms Cu/g diet were cultured for 48 hr in Cu-adequate (16.2 microM) or Cu-deficient (1.0 microM) rat serum. Control embryos cultured in control serum were morphologically normal. Embryos from Cu-deficient dams developed abnormally when cultured in Cu-deficient serum; the abnormalities included distended hindbrains, blisters, blood pooling, and cardiac defects. Control embryos cultured in Cu-deficient serum and Cu-deficient embryos cultured in control serum also showed abnormal development, but to a lesser degree than that of the Cu-deficient embryos cultured in Cu-deficient serum. To test the idea that the above abnormalities were due in part to free radical induced damage occurring secondary to an impaired oxidant defense system, a chemiluminescence assay was used to detect superoxide dismutase (SOD) activity in the cultured embryos. SOD activity was lowest in embryos cultured in Cu-deficient serum. When the Cu-deficient serum was supplemented with antioxidants (CuZnSOD or glutathione peroxidase), its teratogenicity was reduced. These data support the idea that an impaired oxidant defense system contributes to the dysmorphology associated with Cu deficiency. However, the Cu-deficient embryos also had low cytochrome c oxidase activity compared to control embryos--thus, multiple factors are likely contributing to Cu deficiency-induced abnormalities.