Regulation of ceruloplasmin in human hepatic cells by redox active copper: identification of a novel AP-1 site in the ceruloplasmin gene

Quantitative proteomics and RNA-sequencing of mouse liver endothelial cells identify novel regulators of BMP6 by iron

Hepcidin is the master hormone governing systemic iron homeostasis. Iron regulates hepcidin by activating bone morphogenetic protein (BMP)6 expression in liver endothelial cells (LECs), but the mechanisms are incompletely understood. To address this, we performed proteomics and RNA-sequencing on LECs from iron-adequate and iron-loaded mice. Gene set enrichment analysis identified transcription factors activated by high iron, including Nrf-2, which was previously reported to contribute to BMP6 regulation, and c-Jun. Jun (encoding c-Jun) knockdown blocked Bmp6 but not Nrf-2 pathway induction by iron in LEC cultures. Chromatin immunoprecipitation of mouse livers showed iron-dependent c-Jun binding to predicted sites in Bmp6 regulatory regions. Finally, c-Jun inhibitor blunted induction of Bmp6 and hepcidin, but not Nrf-2 activity, in iron-loaded mice. However, Bmp6 and iron parameters were unchanged in endothelial Jun knockout mice. Our data suggest that c-Jun participates in iron-mediated BMP6 regulation independent of Nrf-2, though the mechanisms may be redundant and/or multifactorial.

The biology of mammalian multi-copper ferroxidases

The mammalian multicopper ferroxidases (MCFs) ceruloplasmin (CP), hephaestin (HEPH) and zyklopen (ZP) comprise a family of conserved enzymes that are essential for body iron homeostasis. Each of these enzymes contains six biosynthetically incorporated copper atoms which act as intermediate electron acceptors, and the oxidation of iron is associated with the four electron reduction of dioxygen to generate two water molecules. CP occurs in both a secreted and GPI-linked (membrane-bound) form, while HEPH and ZP each contain a single C-terminal transmembrane domain. These enzymes function to ensure the efficient oxidation of iron so that it can be effectively released from tissues via the iron export protein ferroportin and subsequently bound to the iron carrier protein transferrin in the blood. CP is particularly important in facilitating iron release from the liver and central nervous system, HEPH is the major MCF in the small intestine and is critical for dietary iron absorption, and ZP is important for normal hair development. CP and HEPH (and possibly ZP) function in multiple tissues. These proteins also play other (non-iron-related) physiological roles, but many of these are ill-defined. In addition to disrupting iron homeostasis, MCF dysfunction perturbs neurological and immune function, alters cancer susceptibility, and causes hair loss, but, despite their importance, how MCFs co-ordinately maintain body iron homeostasis and perform other functions remains incompletely understood.

A role for ceruloplasmin in the control of human glioblastoma cell responses to radiation

Background

Glioblastoma (GB) is the most common and most aggressive malignant brain tumor. In understanding its resistance to conventional treatments, iron metabolism and related pathways may represent a novel avenue. As for many cancer cells, GB cell growth is dependent on iron, which is tightly involved in red-ox reactions related to radiotherapy effectiveness. From new observations indicating an impact of RX radiations on the expression of ceruloplasmin (CP), an important regulator of iron metabolism, the aim of the present work was to study the functional effects of constitutive expression of CP within GB lines in response to beam radiation depending on the oxygen status (21% O₂ versus 3% O₂).

Methods and results

After analysis of radiation responses (Hoechst staining, LDH release, Caspase 3 activation) in U251-MG and U87-MG human GB cell lines, described as radiosensitive and radioresistant respectively, the expression of 9 iron partners (TFR1, DMT1, FTH1, FTL, MFRN1, MFRN2, FXN, FPN1, CP) were tested by RTqPCR and western blots at 3 and 8 days following 4 Gy irradiation. Among those, only CP was significantly downregulated, both at transcript and protein levels in the two lines, with however, a weaker effect in the U87-MG, observable at 3% O₂. To investigate specific role of CP in GB radioresistance, U251-MG and U87-MG cells were modified genetically to obtain CP depleted and overexpressing cells, respectively. Manipulation of CP expression in GB lines demonstrated impact both on cell survival and on activation of DNA repair/damage machinery (γH2AX); specifically high levels of CP led to increased production of reactive oxygen species, as shown by elevated levels of superoxide anion, SOD1 synthesis and cellular Fe2 + .

Conclusions

Taken together, these in vitro results indicate for the first time that CP plays a positive role in the efficiency of radiotherapy on GB cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09808-6.

Differential redox proteomic profiles of serum from severe asthma patients after one month of benralizumab and mepolizumab treatment

Mepolizumab and Benralizumab are biological drugs for severe asthma patients able to reduce moderate-to-severe exacerbation rate (peripheral eosinophilial % mepolizumab 1.6 ± 1.2; benralizumab 0; p < 0.0001), improving the quality of life and lung function parameters (FEV1%: mepolizumab 87.1 ± 21.5; benralizumab 89.7 ± 15, p < 0.04). Here we report a preliminary redox proteomic study highlighting the level of oxidative burst present in serum from patients before and after one month of both treatments. Our results highlighted apolipoprotein A1 oxidation after Mepolizumab treatment, that could be related to HDL functionality and could represent a potential biomarker for the treatment. On the other hand, after one month of Benralizumab we detected higher oxidation levels of ceruloplasmin and transthyretin, considered an important oxidative stress biomarker which action help to maintain redox homeostasis.

Intrapulmonary administration of purified NEIL2 abrogates NF-κB-mediated inflammation

Aberrant or constitutive activation of nuclear factor kappa B (NF-κB) contributes to various human inflammatory diseases and malignancies via the upregulation of genes involved in cell proliferation, survival, angiogenesis, inflammation, and metastasis. Thus, inhibition of NF-κB signaling has potential for therapeutic applications in cancer and inflammatory diseases. We reported previously that Nei-like DNA glycosylase 2 (NEIL2), a mammalian DNA glycosylase, is involved in the preferential repair of oxidized DNA bases from the transcriptionally active sequences via the transcription-coupled base excision repair pathway. We have further shown that Neil2-null mice are highly sensitive to tumor necrosis factor α (TNFα)- and lipopolysaccharide-induced inflammation. Both TNFα and lipopolysaccharide are potent activators of NF-κB. However, the underlying mechanism of NEIL2's role in the NF-κB-mediated inflammation remains elusive. Here, we have documented a noncanonical function of NEIL2 and demonstrated that the expression of genes, such as Cxcl1, Cxcl2, Cxcl10, Il6, and Tnfα, involved in inflammation and immune cell migration was significantly higher in both mock- and TNFα-treated Neil2-null mice compared with that in the WT mice. NEIL2 blocks NF-κB's binding to target gene promoters by directly interacting with the Rel homology region of RelA and represses proinflammatory gene expression as determined by co-immunoprecipitation, chromatin immunoprecipitation, and electrophoretic mobility-shift assays. Remarkably, intrapulmonary administration of purified NEIL2 via a noninvasive nasal route significantly abrogated binding of NF-κB to cognate DNA, leading to decreased expression of proinflammatory genes and neutrophil recruitment in Neil2-null as well as WT mouse lungs. Our findings thus highlight the potential of NEIL2 as a biologic for inflammation-associated human diseases.

Ceruloplasmin and oxidative stress in severe eosinophilic asthma patients treated with Mepolizumab and Benralizumab

INTRODUCTION

Severe eosinophilic asthma has been associated with Th2 airway inflammation and elevated proinflammatory cytokines and chemokines, such as IL-5. Precision therapies have recently been shown to improve asthma symptoms with a steroid-sparing effect. Two such therapies, Benralizumab and Mepolizumab, humanized IgG antibodies directed against the IL-5 receptor and IL-5, have been approved for severe eosinophilic asthma.

METHODS

Here we used a differential proteomic approach to analyse serum from patients with severe eosinophilic asthma treated with Benralizumab and Mepolizumab in a search for differential molecular modifications responsible of their effects. Enrichment analysis of differential proteins was performed for the two treatments.

RESULTS AND DISCUSSION

After one month of Benralizumab treatment we detected up-regulation of certain protein species of the antioxidant ceruloplasmin. To investigate oxidative stress, we performed redox proteomics which detected lower oxidative burst after one month of Benralizumab treatment than in the pre-treatment phase or after one month of Mepolizumab therapy.

Correlations Among mRNA Expression Levels of ATP7A, Serum Ceruloplasmin Levels, and Neuronal Metabolism in Unmedicated Major Depressive Disorder

BACKGROUND

Previous studies have found that elevated copper levels induce oxidation, which correlates with the occurrence of major depressive disorder (MDD). However, the mechanism of abnormal cerebral metabolism of MDD patients remains ambiguous. The main function of the enzyme ATPase copper-transporting alpha (ATP7A) is to transport copper across the membrane to retain copper homeostasis, which is closely associated with the onset of mental disorders and cognitive impairment. However, less is known regarding the association of ATP7A expression in MDD patients.

METHODS

A total of 31 MDD patients and 21 healthy controls were recruited in the present study. Proton magnetic resonance spectroscopy was used to assess the concentration levels of N-acetylaspartate, choline (Cho), and creatine (Cr) in brain regions of interest, including prefrontal white matter (PWM), anterior cingulate cortex (ACC), thalamus, lentiform nucleus, and cerebellum. The mRNA expression levels of ATP7A were measured using polymerase chain reaction (SYBR Green method). The correlations between mRNA expression levels of ATP7A and/or ceruloplasmin levels and neuronal biochemical metabolite ratio in the brain regions of interest were evaluated.

RESULTS

The decline in the mRNA expression levels of ATP7A and the increase in ceruloplasmin levels exhibited a significant correlation in MDD patients. In addition, negative correlations were noted between the decline in mRNA expression levels of ATP7A and the increased Cho/Cr ratios of the left PWM, right PWM, and right ACC in MDD patients. A positive correlation between elevated ceruloplasmin levels and increased Cho/Cr ratio of the left PWM was noted in MDD patients.

CONCLUSIONS

The findings suggested that the decline in the mRNA expression levels of ATP7A and the elevated ceruloplasmin levels induced oxidation that led to the disturbance of neuronal metabolism in the brain, which played important roles in the pathophysiology of MDD. The decline in the mRNA expression levels of ATP7A and the elevated ceruloplasmin levels affected neuronal membrane metabolic impairment in the left PWM, right PWM, and right ACC of MDD patients.

Integrated Proteome and Cytokine Profiles Reveal Ceruloplasmin Eliciting Liver Allograft Tolerance via Antioxidant Cascades

Acute rejection (AR) and spontaneous tolerance may occur after allograft orthotopic liver transplants (OLT) performed in certain combinations of donor and recipient rat strains, yet the underlying molecular cascades involved in these conditions remain poorly understood. Comprehensive analysis with proteomic tools revealed that ceruloplasmin was highly expressed during the tolerant period on day 63 post-OLT (POD 63) compared to the rejected samples on POD 14. Meanwhile, cytokine expression profiles implied that the inflammation was significantly stimulated in the AR subjects. Again, protein carbonylation was dramatically upregulated in the rejected subject within the tolerant group. Knockdown of ceruloplasmin would elicit more severe ROS damage, leading to cell death in the presence of H₂O₂, which induced Nrf2 cascade and the recovery of ceruloplasmin to mediate spontaneous tolerance. In summary, ceruloplasmin may contribute to amending the oxidative stress that eventually causes cell apoptosis and to maintaining the survival of hepatocytes in a drug-free tolerance OLT model.

The fungicide thiabendazole causes apoptosis in rat hepatocytes

Many pharmaceutical drugs cause hepatotoxicity in humans leading to severe liver diseases, representing a serious public health issue. This study investigates the ability of the anthelmintic and antifungal drug thiabendazole to cause cell death by apoptosis and metabolic changes in primary cultures of rat hepatocytes. Thiabendazole (200-500 μM) induced apoptosis in hepatocytes after 1 to 24h, causing loss of mitochondrial membrane potential, cytochrome c release from mitochondria, Fas-associated death domain (FADD) translocation from the cytosol to membranes, and activation of caspases-3, -8 and -9. Thus, thiabendazole activated both the mitochondrial and death receptor pathways of apoptosis. Under these conditions, cell death by necrosis was not detected following exposure to thiabendazole (100-500 μM) for 24-48 h, measured by lactate dehydrogenase release and propidium iodide uptake. Furthermore, thiabendazole increased activities of cytochrome P450 (CYP) isoenzymes CYP1A and CYP2B after 24 and 48 h, determined by 7-ethoxyresorufin-O-deethylase (EROD) and 7-pentoxyresorufin-O-dealkylase (PROD) activities, respectively. An important finding is that thiabendazole can eliminate hepatocytes by apoptosis, which could be a sensitive marker for hepatic damage and cell death. This study improves understanding of the mode of cell death induced by thiabendazole, which is important given that humans and animals are exposed to this compound as a pharmaceutical agent and in an environmental context.

Copper bioavailability, blood parameters, and nutrient balance in mink

A 3 × 3 + 1 factorial experiment was conducted based on a completely randomized design to evaluate the effects of different sources of copper on plasma metabolites, nutrient digestibility, relative copper bioavailability, and retention of some minerals in male mink. Animals in the control group were fed a basal diet, which mainly consisted of corn, fish meal, meat and bone meal, and soybean oil, with no copper supplementation. Mink in the other 9 treatments were fed the basal diet supplemented with Cu from reagent-grade copper sulfate (CuSO4), tribasic copper chloride (TBCC), or copper methionine (CuMet). Copper concentrations of the experimental diets were 50, 100, and 150 mg Cu/kg DM. Blood samples were collected via the toe clip at the end of study (d 42) to determine blood hematology and blood metabolites. A metabolism trial of 4 d was conducted during the last week of experimental feeding. There was a linear (P < 0.01) effect of dose of Cu on plasma Cu concentrations, ceruloplasmin concentration, and Cu-Zn superoxide dismutase activity. A linear response to Cu dose was noted for fat (P < 0.05) digestibility. Supplemental dose of Cu linearly increased (P < 0.05) liver Cu and decreased (P < 0.05) liver Zn level but did not alter liver Fe. The concentration of liver Cu of the mink fed with TBCC and CuMet diets was greater (P < 0.05) than that fed CuSO4. Compared with CuSO4 (100%), relative bioavailability values of TBCC were 104 and 104%, based on serum ceruloplasmin and liver copper, respectively, and relative bioavailability values of CuMet were 130 and 111%. CuMet and TBCC are more bioavailable than CuSO4. In conclusion, the relative bioavailability of CuMet obtained in this study was greater than that of CuSO4 and TBCC. Dose of Cu had an important effect on the regulating ceruloplasmin concentration, Cu-Zn superoxide dismutase activity, and the digestion of dietary fat in mink.

Influence of dietary zinc and copper on apparent mineral retention and serum biochemical indicators in young male mink (Mustela vison)

An experiment was conducted in a 3 × 3 (Cu × Zn) factorial experiment based on a completely randomized design to evaluate the effects of dietary copper and zinc on apparent mineral retention and serum biochemical indicators in young male mink on a corn-fish meal based diet. Animals were fed basal diets supplemented with Cu from copper sulfate (CuSO4) and Zn from zinc sulfate (ZnSO4). Supplemental Cu levels were 0, 15, and 30 mg/kg copper, respectively, while supplemental Zn levels were 0, 150, and 300 mg/kg, respectively. A metabolism trial of 4 days was conducted during the last week of experimental feeding. Blood samples were collected via the toe clip to determine blood hematology and blood metabolites. Copper excretion, retention, and digestibility were influenced by dietary copper (P < 0.05), however, there was also a zinc-copper interaction. Copper digestibility and retention were substantially reduced when zinc was added to the low copper diet but showed little change with zinc supplementation of the high copper diet. Both plasma Cu and plasma Zn were influenced by dietary level of the respective mineral (P < 0.05). There was no influence of dietary copper on plasma zinc; however, high Zn in the diet reduced plasma Cu concentrations. There was a zinc-copper interaction for plasma Cu (P = 0.053). Cu-Zn superoxide dismutase (Cu-Zn SOD) activity tended to be influenced by dietary zinc (P = 0.065) and dietary copper (P = 0.035). Dietary copper had a significant effect on ceruloplasmin (CER) and triglyceride (TG) concentrations (P < 0.05). Our results show that moderately high Zn in the diet (Zn:Cu ratio of 40:1) significantly reduce the apparent Cu digestibility. Our results also show that moderately high Cu in the diet increases Cu retention, but not reduces Zn absorption, and moderately high Zn in the diet reduced plasma Cu concentrations and CER activity.

Effects of Copper and/or Cholesterol Overload on Mitochondrial Function in a Rat Model of Incipient Neurodegeneration

Copper (Cu) and cholesterol (Cho) are both associated with neurodegenerative illnesses in humans and animals models. We studied the effect in Wistar rats of oral supplementation with trace amounts of Cu (3 ppm) and/or Cho (2%) in drinking water for 2 months. Increased amounts of nonceruloplasmin-bound Cu were observed in plasma and brain hippocampus together with a higher concentration of ceruloplasmin in plasma, cortex, and hippocampus. Cu, Cho, and the combined treatment Cu + Cho were able to induce a higher Cho/phospholipid ratio in mitochondrial membranes with a simultaneous decrease in glutathione content. The concentration of cardiolipin decreased and that of peroxidation products, conjugated dienes and lipoperoxides, increased. Treatments including Cho produced rigidization in both the outer and inner mitochondrial membranes with a simultaneous increase in permeability. No significant increase in Cyt C leakage to the cytosol was observed except in the case of cortex from rats treated with Cu and Cho nor were there any significant changes in caspase-3 activity and the Bax/Bcl2 ratio. However, the A β (1-42)/(1-40) ratio was higher in cortex and hippocampus. These findings suggest an incipient neurodegenerative process induced by Cu or Cho that might be potentiated by the association of the two supplements.

Metal ions in macrophage antimicrobial pathways: emerging roles for zinc and copper

The immunomodulatory and antimicrobial properties of zinc and copper have long been appreciated. In addition, these metal ions are also essential for microbial growth and survival. This presents opportunities for the host to either harness their antimicrobial properties or limit their availability as defence strategies. Recent studies have shed some light on mechanisms by which copper and zinc regulation contribute to host defence, but there remain many unanswered questions at the cellular and molecular levels. Here we review the roles of these two metal ions in providing protection against infectious diseases in vivo, and in regulating innate immune responses. In particular, we focus on studies implicating zinc and copper in macrophage antimicrobial pathways, as well as the specific host genes encoding zinc transporters (SLC30A, SLC39A family members) and CTRs (copper transporters, ATP7 family members) that may contribute to pathogen control by these cells.

Ototoxic Model of Oxaliplatin and Protection from Nicotinamide Adenine Dinucleotide

Oxaliplatin, an anticancer drug commonly used to treat colorectal cancer and other tumors, has a number of serious side effects, most notably neuropathy and ototoxicity. To gain insights into its ototoxic profile, oxaliplatin was applied to rat cochlear organ cultures. Consistent with it neurotoxic propensity, oxaliplatin selectively damaged nerve fibers at a very low dose 1 μM. In contrast, the dose required to damage hair cells and spiral ganglion neurons was 50 fold higher (50 μM). Oxailiplatin-induced cochlear lesions initially increased with dose, but unexpectedly decreased at very high doses. This non-linear dose response could be related to depressed oxaliplatin uptake via active transport mechanisms. Previous studies have demonstrated that axonal degeneration involves biologically active processes which can be greatly attenuated by nicotinamide adenine dinucleotide (NAD+). To determine if NAD+ would protect spiral ganglion axons and the hair cells from oxaliplatin damage, cochlear cultures were treated with oxaliplatin alone at doses of 10 μM or 50 μM respectively as controls or combined with 20 mM NAD+. Treatment with 10 μM oxaliplatin for 48 hours resulted in minor damage to auditory nerve fibers, but spared cochlear hair cells. However, when cochlear cultures were treated with 10 μM oxaliplatin plus 20 mM NAD+, most auditory nerve fibers were intact. 50 μM oxaliplatin destroyed most of spiral ganglion neurons and cochlear hair cells with apoptotic characteristics of cell fragmentations. However, 50 μM oxaliplatin plus 20 mM NAD+ treatment greatly reduced neuronal degenerations and hair cell missing. The results suggested that NAD+ provides significant protection against oxaliplatin-induced neurotoxicity and ototoxicity, which may be due to its actions of antioxidant, antiapoptosis, and energy supply.

Relevance of copper transporter 1 for cisplatin resistance in human ovarian carcinoma cells

Defects in intracellular accumulation of the antitumour drug cisplatin are a commonly observed feature in the cells selected for cisplatin resistance. Copper transporter 1 (CTR1) has been suggested to play an important role in drug uptake and resistance. Here, we describe a detailed investigation of the involvement of CTR1 in cisplatin uptake and its relevance for cisplatin resistance using a well characterised sensitive/cisplatin-resistant cell line pair: A2780 human ovarian carcinoma cell line and its cisplatin-resistant variant A2780cis. A2780cis cells showed decreased cisplatin accumulation and lower CTR1 expression compared to A2780 cells. Co-incubation with copper sulphate affected neither cisplatin accumulation (determined by flameless atomic absorption spectrometry) nor its cytotoxicity (determined using an MTT-assay, MTT=3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide). In both cell lines, CTR1 was localised near the nucleus as found using confocal fluorescence microscopy. The steady-state localisation of the protein in perinuclear region appears to involve its continuous endocytosis from cell surface. In contrast to copper, cisplatin exposure had no influence on the sub cellular localisation of CTR1. Co-localisation between CTR1 and a fluorescent cisplatin analogue labelled with carboxyfluorescein-diacetate could be observed in vesicular structures when continuous retrieval of the protein from cell membrane was inhibited. Our results strongly suggest that CTR1 mediates cisplatin uptake in the cell lines studied. Upon its transport across the plasma membrane by CTR1 the platinum drug is likely to be internalised along with the protein. Our findings imply that reduced CTR1 expression accounts for decreased cisplatin accumulation and represents one of the determinants of cisplatin resistance in A2780cis cell line.

Putative biomarker genes for grading clear cell renal cell carcinoma

OBJECTIVE

The initial objective of this renal cancer study was to identify gene sets in clear cell renal cell carcinoma (ccRCC) to support grading of ccRCC histopathology.

MATERIALS AND METHODS

Preselected ccRCC tumor tissues of grade 1 (G1, n = 14) and grade 3 (G3, n = 15) as well es 14 normal kidney tissues thereof were subjected to microarray expression analysis using Human Genome U133 Plus 2.0 Array. Event ratio scoring, hierarchical clustering and principal component analysis were used to determine gene sets that distinguish expression profiles from normal kidney tissue, G1 and G3 tumor tissues.

RESULTS

An initial set of 73 genes provided seven gene subclusters (SC01 to SC07) that distinguish RNA expression profiles from G1, G3 tumor and normal kidney tissues. A ranked list of 24 genes was determined that separated G1 from G3 tumors in high concordance with histopathological grading confirmed by immunohistochemical analysis of ceruloplasmin protein expression.

CONCLUSION

A final set of 24 genes has been determined awaiting further validation on the RNA as well as on the protein level by studying an additional cohort of ccRCC patients. A reliable separation of G1 and G3 tumor grades will be instrumental to foster and direct the administration of upcoming targeted therapeutics of ccRCC tumors in a more predictive and reliable manner.

Interleukin-1β induces ceruloplasmin and ferroportin-1 gene expression via MAP kinases and C/EBPβ, AP-1, and NF-κB activation

Previously, we demonstrated that IL-1β was able to increase iron efflux from glial cells through a coordinate induction of both ferroportin-1 (Fpn) and ceruloplasmin (Cp) synthesis. In this study, we have investigated the signaling pathways that are involved in the transcriptional activation of the Cp and Fpn. Our data show that the expression of Cp and Fpn in response to IL-1β requires the activation of MAP kinase pathways as a consequence of an IL-1β receptor stimulation. Moreover, we have observed that IL-1β regulates the expression of Cp and Fpn genes through (i) p38 MAPK-mediated activation of C/EBP transcription factor, (ii) ERK1/2-, JNK1- and partially p38 MAPK-dependent activation of AP-1, and through (iii) activation of NF-κB partially mediated by p38 MAPK.

Glutathione synthesis inhibitor butathione sulfoximine regulates ceruloplasmin by dual but opposite mechanism: Implication in hepatic iron overload

Glutathione (GSH) depletion is often detected in chronic pathological conditions like hepatitis C infection, alcohol consumption or xenobiotic assault with simultaneous reactive oxygen species (ROS) generation and hepatic iron overload. However, relation between GSH depletion and regulators of iron homeostasis is not clear so far. To determine that hepatic HepG2 cells were treated with GSH synthesis inhibitor butathione sulfoximine (BSO) and a dual regulation of ceruloplasmin (Cp) that involves in hepatic iron release was detected unlike other iron homeostasis regulators. BSO treatment that caused marginal GSH deficiency increased Cp synthesis due to increased transcription mediated by activator protein (AP)-1-binding site. In higher GSH deficiency (> 40 %) with increased ROS generation, Cp expression was decreased due to promotion of Cp mRNA decay mediated by 3'untranslated region (3'UTR) as found by transfecting chimera of chloramphenicol acetyl transferase (CAT) gene with Cp 3'UTR. RNA gel shift assay showed significant reduction in 3'UTR binding protein complex in similar condition. Decreased CAT expression and RNA-protein complex binding are reversed by pretreatment with antioxidant N-acetyl cysteine suggesting 3'UTR binding protein complex is redox-sensitive. This unique and opposite regulation of Cp provides a mechanism of hepatic iron-deposition during glutathione deficiency detected in chronic pathological conditions.

Relevance of non-ceruloplasmin copper to oxidative stress in patients with hepatocellular carcinoma

Altered copper homeostasis and oxidative stress have been observed in patients with hepatocellular carcinoma. Non-ceruloplasmin copper, the free form, is a potent pro-oxidant than the protein bound copper. The aim of the present study was to evaluate which form of copper can be correlated with the oxidative stress in the circulation and in the malignant liver tissues of hepatocellular carcinoma patients. Hepatocellular carcinoma patients (grades II and III, n = 18) were enrolled in this study. Serum levels of total, free and bound copper, ceruloplasmin, iron, iron-binding capacity, lipid peroxidation products, and enzymatic and non-enzymatic antioxidants were quantified in serum and in malignant liver tissues and compared with those of normal samples (n = 20). A significant positive correlation between the serum non-ceruloplasmin copper and lipid peroxidation products and negative correlation with antioxidants were observed in hepatocellular carcinoma patients. In liver tissue, glutathione peroxidase, superoxide dismutase, and catalase activity were significantly decreased with concomitant elevation in oxidative stress markers. Our experiment revealed that the elevation in non-ceruloplasmin copper has high relevance with the oxidative stress than the bound copper.

Glycoproteomic analysis of WGA-bound glycoprotein biomarkers in sera from patients with lung adenocarcinoma

Differential protein expression profiles in the serum samples from patients with lung adenocarcinoma may be associated with glycosylation during cancer development. In this study, we used various glycoproteomic approaches to investigate the different glycoproteomic profiles of human normal and lung adenocarcinoma serum samples and to investigate putative altered glycoprotein biomarkers. In our preliminary screening, FITC-labeled lectin staining was used for the detection of specific glycoprotein profiles. wheat germ agglutinin (WGA) lectin had the highest level of specific binding to glycoproteins in both samples. We enriched for glycoproteins in the serum samples using WGA lectin affinity and then performed co-immunoprecipitation with anti-haptoglobin and 2-DE, 2-D difference in-gel electrophoresis and MS analyses. From these analyses, we identified 39 differentially expressed proteins, including 27 up-regulated proteins and 12 down-regulated proteins. Bioinformatics tools were used to search for protein ontology, category classifications and prediction of glycosylation sites. In addition, three up-regulated glycoproteins (adiponectin, cerulolasmin and glycosylphosphatidyl-inositol-80) and two down-regulated glycoproteins (cyclin H and Fyn) that were found to be correlated with lung cancer development were validated by Western blot analysis. We suggest that these altered glycoproteins may be useful as biomarkers for lung cancer development and progression.

A mouse mammary gland involution mRNA signature identifies biological pathways potentially associated with breast cancer metastasis

Mouse mammary gland involution resembles a wound healing response with suppressed inflammation. Wound healing and inflammation are also associated with tumour development, and a 'wound-healing' gene expression signature can predict metastasis formation and survival. Recent studies have shown that an involuting mammary gland stroma can promote metastasis. It could therefore be hypothesised that gene expression signatures from an involuting mouse mammary gland may provide new insights into the physiological pathways that promote breast cancer progression. Indeed, using the HOPACH clustering method, the human orthologues of genes that were differentially regulated at day 3 of mammary gland involution and showed prolonged expression throughout the first 4 days of involution distinguished breast cancers in the NKI 295 breast cancer dataset with low and high metastatic activity. Most strikingly, genes associated with copper ion homeostasis and with HIF-1 promoter binding sites were the most over-represented, linking this signature to hypoxia. Further, six out of the ten mRNAs with strongest up-regulation in cancers with poor survival code for secreted factors, identifying potential candidates that may be involved in stromal/matrix-enhanced metastasis formation/breast cancer development. This method therefore identified biological processes that occur during mammary gland involution, which may be critical in promoting breast cancer metastasis that could form a basis for future investigation, and supports a role for copper in breast cancer development.

Reactive oxygen species regulate ceruloplasmin by a novel mRNA decay mechanism involving its 3'-untranslated region: implications in neurodegenerative diseases

Ceruloplasmin (Cp), a copper-containing protein, plays a significant role in body iron homeostasis as aceruloplasminemia patients and Cp knock-out mice exhibit iron overload in several tissues including liver and brain. Several other functions as oxidant, as antioxidant, and in nitric oxide metabolism are also attributed to Cp. Despite its role in iron oxidation and other biological oxidation reactions the regulation of Cp by reactive oxygen species (ROS) remains unexplored. Cp is synthesized in liver as a secretory protein and predominantly as a glycosylphosphatidylinositol-anchored membrane-bound form in astroglia. In this study we demonstrated that Cp expression is decreased by an mRNA decay mechanism in response to extracellular (H2O2) or intracellular oxidative stress (by mitochondrial chain blockers rotenone or antimycin A) in both hepatic and astroglial cells. The promotion of Cp mRNA decay is conferred by its 3'-untranslated region (UTR). When chloramphenicol acetyltransferase (CAT) gene was transfected as a chimera with Cp 3'-UTR in hepatic or astroglial cells, in response to either H2O2, rotenone, or antimycin A, the expression of CAT transcript was decreased, whereas expression of a 3'-UTR-less CAT transcript remained unaffected. RNA gel shift assay showed significant reduction in 3'-UTR-binding protein complex by ROS in both cell types that was reversed by the antioxidant N-acetylcysteine suggesting that ROS affects RNA-protein complex formation to promote Cp mRNA decay. Our finding is not only the first demonstration of regulation of Cp by ROS by a novel post-transcriptional mechanism but also provides a mechanism of iron deposition in neurodegenerative diseases.

Differential expression of ceruloplasmin isoforms in the cerebrospinal fluid of amyotrophic lateral sclerosis patients

Amyotrophic lateral sclerosis (ALS) a fatal degenerative disease that selectively affects motor neurons, likely results from a complex interplay among oxidative injury, excitotoxic stimulation, protein aggregation and genetic factors. Ceruloplasmin (Cp) protein is a ferroxidase that oxidizes toxic ferrous iron to its nontoxic ferric form, protecting the central nervous system (CNS) from iron deposition. Cp is thus considered as one of the main systems dedicated to the protection of the CNS from oxidative stress damage. We investigated Cp protein behaviour in the cerebrospinal fluid (CSF) of ALS patients of recent onset. An increased expression of Cp was observed in ALS (n = 16) compared to two control groups (healthy subjects, n = 11 and peripheral neuropathy patients, n = 10). 2-DE analysis revealed a differential expression of Cp isoforms in ALS patients compared to controls. ALS samples showed an increase in the relative abundance of more basic Cp forms, corresponding to the nonsialylated proteins. Despite the increase in protein expression, ferroxidase activity evaluated in the CSF of ALS patients was comparable to that of the controls, indicating a Cp functional impairment. Ceruloplasmin isoforms profile may be proposed as disease feature that could provide insight into the molecular mechanisms of ALS pathogenesis.

Hyaluronan regulates ceruloplasmin production by gliomas and their treatment-resistant multipotent progenitors

Ceruloplasmin (glycosylphosphatidylinositol-linked ferroxidase associated with normal astrocytes) can also be secreted by glioma cells, where its function is unknown. Ceruloplasmin is not only present in glioma cells and in human glioma specimens but also is enriched in highly malignant glioma stem-like cells. Hyaluronan is a large extracellular glycosaminoglycan that enhances malignant glioma behaviors by interacting with CD44 receptors and by downstream activation of signaling proteins and transporters associated with malignancy. We examined the relationship between hyaluronan and ceruloplasmin expression in glioma stem-like cells. Antagonism of hyaluronan interactions with short-fragment hyaluronan oligomers decreased ceruloplasmin expression in parental and stem-like glioma cells in vivo and in cell culture, implying that hyaluronan regulates ceruloplasmin expression. Further gain and loss-of-function studies are needed to fully define the relationship between hyaluronan and ceruloplasmin, and ceruloplasmin's effect on malignant behaviors.

Sera proteomic biomarker profiling in HIV-1 infected subjects with cognitive impairment

HIV-1 infection of the brain commonly leads to cognitive impairments (CIs). In its most severe form, HIV-1 associated dementia (HAD) is associated with advanced immune suppression and debilitating loss of memory, behavioral, and motor functions. Despite significant research activities, diagnosis remains one of exclusion. Bioimaging, neuropsychological testing, and viral and immune biomarkers serve to support but not define a diagnosis of HIV-1 associated CI. This is timely and required as brain injury triggered by HIV-1 can be controlled, in part, by antiretroviral medicines. The recent development of proteomics has opened new ways to study viral-host interactions which may provide new insight into treatment and disease monitoring. To this end, we developed a proteomics platform for HIV-1 associated CI biomarker discovery and used it to perform a pilot study for sera-associated HAD proteins. A 2-DE map of a serum proteome was focused on differentially expressed proteins. Differential expression of two proteins was validated by Western blot tests identifying afamin and ceruloplasmin as a potential biomarkers for CI associated with advanced HIV-1 infection.

The uptake and fate of vanadyl ion in ascidian blood cells and a detailed hypothesis for the mechanism and location of biological vanadium reduction. A visible and X-ray absorption spectroscopic study

Vanadium K-edge X-ray absorption spectroscopy (XAS) has been used to track the uptake and fate of VO(2+) ion in blood cells from Ascidia ceratodes, following exposure to dithiothreitol (DTT) or to DTT plus VO(2+). The full range of endogenous vanadium was queried by fitting the XAS of blood cells with the XAS spectra of model vanadium complexes. In cells exposed only to DTT, approximately 0.4% of a new V(III) species was found in a site similar to Na[V(edta)(H(2)O)]. With exposure to DTT and VO(2+), average intracellular [VO(aq)](2+) increased from 3% to 5%, and 6% of a new complexed form of vanadyl ion appeared evidencing a ligand array similar to [VO(edta)](2-). At the same time, the relative ratio of blood cell [V(H(2)O)(6)](3+) increased at the expense of [V(H(2)O)(5)(SO(4))](+) in a manner consistent with a significant increase in endogenous acidity. In new UV/Visible experiments, VO(2+) could be reduced to 7-coordinate [V(nta)(H(2)O)(3)] or [V(nta)(ida)](2-) with cysteine methyl ester in pH 6.5 solution. Ascorbate reduced [VO(edta)](2-) to 7-coordinate [V(edta)(H(2)O)](-), while [VO(trdta)](2-) was unreactive. These results corroborate the finding that the reductive EMF of VO(2+) is increased by the availability of a 7-coordinate V(III) product. Finally, a new and complete hypothesis is proposed for an ascidian vanadate reductase. The structure of the enzyme active site, the vanadate-vanadyl-vanadic reduction mechanism, the cellular locale, and elements of the regulatory machinery governing the biological reduction of vanadate and vanadyl ion by ascidians are all predicted. Together these constitute the new field of vanadium redox enzymology.

The antioxidant response induced by Lonicera caerulaea berry extracts in animals bearing experimental solid tumors

Lonicera caerulea is a species of bush native to the Kamchatka Peninsula (Russian Far East) whose berries have been extensively studied due to their potential high antioxidant activity. The aim of our work was to investigate the in vivo effects of the antioxidant action of Lonicera caerulea berry extracts on the dynamics of experimentally-induced tumors. Our data showed that aqueous Lonicera caerulaea extracts reduced the tumor volume when administered continuously during the tumor growth and development stages, but augmented the tumor growth when the administration of extracts started three weeks before tumor grafting. Prolonged administration of Lonicera caerulaea berry extracts induced the antioxidant defense mechanism in the tumor tissues, while surprisingly amplifying the peripheral oxidative stress.

Effects of iron loading on muscle: genome-wide mRNA expression profiling in the mouse

Background

Hereditary hemochromatosis (HH) encompasses genetic disorders of iron overload characterized by deficient expression or function of the iron-regulatory hormone hepcidin. Mutations in 5 genes have been linked to this disease: HFE, TFR2 (encoding transferrin receptor 2), HAMP (encoding hepcidin), SLC40A1 (encoding ferroportin) and HJV (encoding hemojuvelin). Hepcidin inhibits iron export from cells into plasma. Hemojuvelin, an upstream regulator of hepcidin expression, is expressed in mice mainly in the heart and skeletal muscle. It has been suggested that soluble hemojuvelin shed by the muscle might reach the liver to influence hepcidin expression. Heart muscle is one of the target tissues affected by iron overload, with resultant cardiomyopathy in some HH patients. Therefore, we investigated the effect of iron overload on gene expression in skeletal muscle and heart using Illumina™ arrays containing over 47,000 probes. The most apparent changes in gene expression were confirmed using real-time RT-PCR.

Results

Genes with up-regulated expression after iron overload in both skeletal and heart muscle included angiopoietin-like 4, pyruvate dehydrogenase kinase 4 and calgranulin A and B. The expression of transferrin receptor, heat shock protein 1B and DnaJ homolog B1 were down-regulated by iron in both muscle types. Two potential hepcidin regulatory genes, hemojuvelin and neogenin, showed no clear change in expression after iron overload.

Conclusion

Microarray analysis revealed iron-induced changes in the expression of several genes involved in the regulation of glucose and lipid metabolism, transcription and cellular stress responses. These may represent novel connections between iron overload and pathological manifestations of HH such as cardiomyopathy and diabetes.