Ferritin, iron homeostasis, and oxidative damage

Characteristics of follicular fluid in ovaries with endometriomas

The study of follicular fluid (FF) content nearby endometriomas may assist in elucidating pathophysiology, possible biomarkers related to this disease and the effect of endometriomas on ovarian physiology. As the question "how endometrioma may intrude the physiology of ovarian tissue?" is still open, we aimed to summarize the molecular evidence supporting the idea that endometriomas can negatively influence the content of the surrounding ovarian follicles. An alteration of the iron metabolism and an increased ROS (reactive oxygen species) generation characterize the intrafollicular environment adjacent to endometriomas. Other potentially negative effects include decreased testosterone and anti-Mullerian hormone FF levels although these have been only partially clarified. Alterations in lipid and proteomic patterns have been also observed in FF samples nearby endometriomas. The possibility that endometriomas per se may influence IVF clinical results as a consequence of the detrimental impact on the local intrafollicular environment is also discussed.

Positive correlation between insulin resistance and iron overload-induced oxidative stress in patients with fanconi anemia (FA)- and non-FA-related bone marrow failure: The results of a multicenter study

This study investigated the relationship between DNA, protein, and lipid oxidations and insulin resistance in patients with Fanconi anemia (FA)- and non-FA-related bone marrow failure. Sixteen patients with FA, 7 non-FA-related aplastic anemia, and 10 controls were included in the study. Fasting blood glucose, simultaneous insulin, hepcidin, ferritin, 8-hydroxy deoxyguanosine (8-OHdG), protein carbonyls, malondialdehyde (MDA), and homeostatic model assessment-insulin resistance (HOMA-IR) were investigated in the patients and controls. Diepoxybutane test-positive (DEB+) patients were diagnosed with FA, whereas DEB-patients were diagnosed as non-FA. 8-OHdG levels in both FA and non-FA patients were significantly higher than those in the controls (P = .001 and P = .005, respectively). Serum ferritin levels were also higher in FA and non-FA patients than in the controls (P = .0001 and P = .005, respectively). Insulin resistance (IR) was significantly higher in FA patients than in non-FA patients and controls (P = .005 and P = .015, respectively). Significant differences were observed between 8-OHdG, ferritin, and MDA levels in patients with or without IR (P = .009, P = .001, and P = .013, respectively). Moderate and strong relations of 44% and 85% were determined between IR and ferritin levels in patients with FA or non-FA (P = .08 and P = .014, respectively). FA and non-FA patients exhibited a tendency to IR. IR was related to ferritin levels, and ferritin levels were also correlated with oxidative stress. These findings suggest that the increased rate of IR in patients with FA and non-FA may derive from increased oxidative stress, which may in turn be due to elevated serum ferritin levels.

Using environmental proteomics to assess pollutant response of Carcinus maenas along the Tunisian coast

Biochemical responses to pollutants were studied at four Tunisia littoral sites using Carcinus maenas as a bioindicator. Proteomic analysis was used to assess the global impact of complex pollution mixtures, and to provide new biomarkers and basic insights into pollutant toxicity. Metal contents and metallothionein levels followed a gradient based on sampling sites: Bizerte ≫ Teboulba > Gargour~Mahres. Approximately 900 and 700 spots were resolved in digestive glands and gills, respectively. Gills from Bizerte animals had the maximum number of altered spots, mostly upregulated. In other locations, the number of altered spots in gills decreased in parallel to total metals in in the following order: Teboulba > Gargour > Mahres (mostly downregulated). Out of the 39 spots excised, ten proteins were identified in digestive glands and eight in gills. Digestive glands of Bizerte crabs had higher levels of ferritin, three vitellogenin forms and mannose-binding protein, while Gargour crabs had higher levels of four cryptocyanin forms. Gills of Bizerte crabs had higher levels of ferritin, three vitellogenins forms, lectin 4C, actin, and collagenolytic serine protease. Proteins with altered expression in crabs from Tunisia littoral are related to molting, oxidative stress and inflammation, innate immune response, and proteolysis.

Proteomic Analysis of Minimally Damaged Renal Tubular Tissue from Two-Kidney-One-Clip Hypertensive Rats Demonstrates Extensive Changes Compared to Tissue from Controls

BACKGROUND

Tubular atrophy and interstitial fibrosis mark the final stage in most forms of progressive kidney diseases. Little is known regarding changes in the tubular proteome. In this study, we investigated changes in the tubular proteome of normal or minimally damaged tubular tissue in the non-clipped kidney from rats with two-kidney one-clip (2K1C) hypertension.

METHODS

Formalin-fixed paraffin-embedded kidney sections from four 2K1C rats with hypertensive kidney damage and 6 sham rats were used. Tubulointerstitial tissue without discernable interstitial expansion or pronounced tubular alterations was microdissected and this was assumed to represent an early stage of chronic tubular damage in 2K1C. Samples were analyzed by mass spectrometry and relative protein abundances were compared between 2K1C and sham.

RESULTS

A total of 1,160 proteins were identified with at least 2 unique peptides, allowing for relative quantitation between samples. Among these, 151 proteins were more abundant, and 192 proteins were less abundant in 2K1C compared with sham. Transgelin, vimentin and creatine kinase B-type were among the proteins that were most increased in 2K1C. Ingenuity Pathway Analysis showed increased abundance of proteins related to Rho signaling and protein turnover (eIF2 signaling and protein ubiquitination), and decreased abundance of proteins related to fatty acid β-oxidation.

CONCLUSION

Tubular tissue from normal or minimally damaged hypertensive kidney damage demonstrate extensive proteomic changes with upregulation of pathways associated with progressive kidney damage, such as Rho signaling and protein turnover. Thus, proteomics presents itself to be a promising tool for the discovery of early damage markers from not yet morphologically visible tubular damage.

Tumor cell survival pathways activated by photodynamic therapy: a molecular basis for pharmacological inhibition strategies

Photodynamic therapy (PDT) has emerged as a promising alternative to conventional cancer therapies such as surgery, chemotherapy, and radiotherapy. PDT comprises the administration of a photosensitizer, its accumulation in tumor tissue, and subsequent irradiation of the photosensitizer-loaded tumor, leading to the localized photoproduction of reactive oxygen species (ROS). The resulting oxidative damage ultimately culminates in tumor cell death, vascular shutdown, induction of an antitumor immune response, and the consequent destruction of the tumor. However, the ROS produced by PDT also triggers a stress response that, as part of a cell survival mechanism, helps cancer cells to cope with the PDT-induced oxidative stress and cell damage. These survival pathways are mediated by the transcription factors activator protein 1 (AP-1), nuclear factor E2-related factor 2 (NRF2), hypoxia-inducible factor 1 (HIF-1), nuclear factor κB (NF-κB), and those that mediate the proteotoxic stress response. The survival pathways are believed to render some types of cancer recalcitrant to PDT and alter the tumor microenvironment in favor of tumor survival. In this review, the molecular mechanisms are elucidated that occur post-PDT to mediate cancer cell survival, on the basis of which pharmacological interventions are proposed. Specifically, pharmaceutical inhibitors of the molecular regulators of each survival pathway are addressed. The ultimate aim is to facilitate the development of adjuvant intervention strategies to improve PDT efficacy in recalcitrant solid tumors.

H ferritin silencing induces protein misfolding in K562 cells: A Raman analysis

The redox state of the cell is involved in the regulation of many physiological functions as well as in the pathogenesis of several diseases, and is strictly dependent on the amount of iron in its catalytically active state. Alterations of iron homeostasis determine increased steady-state concentrations of Reactive Oxygen Species (ROS) that cause lipid peroxidation, DNA damage and altered protein folding. Ferritin keeps the intracellular iron in a non-toxic and readily available form and consequently plays a central role in iron and redox homeostasis. The protein is composed by 24 subunits of the H- and L-type, coded by two different genes, with structural and functional differences. The aim of this study was to shed light on the role of the single H ferritin subunit (FHC) in keeping the native correct protein three-dimensional structure. To this, we performed Raman spectroscopy on protein extracts from K562 cells subjected to FHC silencing. The results show a significant increase in the percentage of disordered structures content at a level comparable to that induced by H2O2 treatment in control cells. ROS inhibitor and iron chelator were able to revert protein misfolding. This integrated approach, involving Raman spectroscopy and targeted-gene silencing, indicates that an imbalance of the heavy-to-light chain ratio in the ferritin composition is able to induce severe but still reversible modifications in protein folding and uncovers new potential pathogenetic mechanisms associated to intracellular iron perturbation.

Profile of oxidative stress markers is dependent on vitamin D levels in patients with chronic hepatitis C

OBJECTIVES

Although vitamin D deficiency can change liver injury progression in patients with hepatitis C virus (HCV), the main molecular mechanisms involved are largely unknown. The first aim of this study was to evaluate the association between oxidative stress and hypovitaminosis D in patients with HCV. The second aim was to verify whether oxidative stress is involved in the molecular mechanisms related to liver injury.

METHODS

The study included 147 participants: 89 controls and 58 patients with HCV (vitamin D < 30, n = 32; vitamin D > 30, n = 26).

RESULTS

Patients with HCV and hypovitaminosis D presented significantly higher aminotransferase-to-platelet ratio index (APRI; P = 0.0464) and viral load (P = 0.0426) levels than patients with HCV without hypovitaminosis D. Regarding oxidative stress, HCV patients with hypovitaminosis D had higher advanced oxidation protein products (P = 0.0409), nitric oxide metabolites (P = 0.0206) levels, and oxidative stress index (P = 0.0196), whereas total radical-trapping antioxidant parameter (P = 0.0446) levels were significantly lower than HCV patients without hypovitaminosis D. Vitamin D in patients with HCV showed inverse correlations with levels of iron (r = -0.407, P = 0.0285), ferritin (r = -0.383, P = 0.0444), APRI (r = -0.453, P = 0.0154) and plasma lipid hydroperoxides levels (r = -0.426, P = 0.0189).

CONCLUSION

Vitamin D insufficiency contributes to the inflammatory process and oxidative stress imbalance in patients with HCV. The profile of oxidative stress markers in these patients depends on vitamin D levels, which probably change intracellular signalling pathways and increase inflammation and liver injury.

Cellular magnetic resonance imaging contrast generated by the ferritin heavy chain genetic reporter under the control of a Tet-On switch

INTRODUCTION

Despite the strong appeal of ferritin as a magnetic resonance imaging (MRI) reporter for stem cell research, no attempts have been made to apply this genetic imaging reporter in stem cells in an inducible manner, which is important for minimizing the potential risk related to the constitutive expression of an imaging reporter. The aim of the present study was to develop an inducible genetic MRI reporter system that enables the production of intracellular MRI contrast as needed.

METHODS

Ferritin heavy chain (FTH1) was genetically modified by adding a Tet-On switch. A C3H10T1/2 cell line carrying Tet-FTH1 (C3H10T1/2-FTH1) was established via lentiviral transduction. The dose- and time-dependent expression of FTH1 in C3H10T1/2 cells was assessed by western blot and immunofluorescence staining. The induced "ON" and non-induced "OFF" expressions of FTH1 were detected using a 3.0 T MRI scanner. Iron accumulation in cells was analyzed by Prussian blue staining and transmission electron microscopy (TEM).

RESULTS

The expression of FTH1 was both dose- and time-dependently induced, and FTH1 expression peaked in response to induction with doxycycline (Dox) at 0.2 μg/ml for 72 h. The induced expression of FTH1 resulted in a significant increase in the transverse relaxation rate of C3H10T1/2-FTH1 cells following iron supplementation. Prussian blue staining and TEM revealed extensive iron accumulation in C3H10T1/2-FTH1 cells in the presence of Dox.

CONCLUSIONS

Cellular MRI contrast can be produced as needed via the expression of FTH1 under the control of a Tet-On switch. This finding could lay the groundwork for the use of FTH1 to track stem cells in vivo in an inducible manner.

Systematic review of anaemia and inflammatory markers in chronic obstructive pulmonary disease

This systematic review synthesizes the relevant published articles on the prevalence of anaemia in patients with chronic obstructive pulmonary disease (COPD) and its relationship with inflammatory markers. The upregulation of erythropoietin in anaemia maintains homeostasis. However, anaemic COPD patients do not respond to increased levels of erythropoietin. The increased levels could be an indicator of the peripheral erythropoietin resistance in COPD. Anaemia and inflammation are associated with an increased risk of hospitalization and mortality in these patients. The understanding of anaemia in chronic inflammation is that anaemia is at least partially due to the excessive production of inflammatory cytokines, which can contribute to improvements in the management, prognosis, and survival of patients with COPD and anaemia.

Pharmacological induction of ferritin prevents osteoblastic transformation of smooth muscle cells

Vascular calcification is a frequent complication of atherosclerosis, diabetes and chronic kidney disease. In the latter group of patients, calcification is commonly seen in tunica media where smooth muscle cells (SMC) undergo osteoblastic transformation. Risk factors such as elevated phosphorus levels and vitamin D3 analogues have been identified. In the light of earlier observations by our group and others, we sought to inhibit SMC calcification via induction of ferritin. Human aortic SMC were cultured using β-glycerophosphate with activated vitamin D3 , or inorganic phosphate with calcium, and induction of alkaline phosphatase (ALP) and osteocalcin as well as accumulation of calcium were used to monitor osteoblastic transformation. In addition, to examine the role of vitamin D3 analogues, plasma samples from patients on haemodialysis who had received calcitriol or paricalcitol were tested for their tendency to induce calcification of SMC. Addition of exogenous ferritin mitigates the transformation of SMC into osteoblast-like cells. Importantly, pharmacological induction of heavy chain ferritin by 3H-1,2-Dithiole-3-thione was able to inhibit the SMC transition into osteoblast-like cells and calcification of extracellular matrix. Plasma samples collected from patients after the administration of activated vitamin D3 caused significantly increased ALP activity in SMC compared to the samples drawn prior to activated vitamin D3 and here, again induction of ferritin diminished the osteoblastic transformation. Our data suggests that pharmacological induction of ferritin prevents osteoblastic transformation of SMC. Hence, utilization of such agents that will cause enhanced ferritin synthesis may have important clinical applications in prevention of vascular calcification.

Self-assembly is prerequisite for catalysis of Fe(II) oxidation by catalytically active subunits of ferritin

Fe(III) storage by ferritin is an essential process of the iron homeostasis machinery. It begins by translocation of Fe(II) from outside the hollow spherical shape structure of the protein, which is formed as the result of self-assembly of 24 subunits, to a di-iron binding site, the ferroxidase center, buried in the middle of each active subunit. The pathway of Fe(II) to the ferroxidase center has remained elusive, and the importance of self-assembly for the functioning of the ferroxidase center has not been investigated. Here we report spectroscopic and metal ion binding studies with a mutant of ferritin from Pyrococcus furiosus (PfFtn) in which self-assembly was abolished by a single amino acid substitution. We show that in this mutant metal ion binding to the ferroxidase center and Fe(II) oxidation at this site was obliterated. However, metal ion binding to a conserved third site (site C), which is located in the inner surface of each subunit in the vicinity of the ferroxidase center and is believed to be the path for Fe(II) to the ferroxidase center, was not disrupted. These results are the basis of a new model for Fe(II) translocation to the ferroxidase center: self-assembly creates channels that guide the Fe(II) ions toward the ferroxidase center directly through the protein shell and not via the internal cavity and site C. The results may be of significance for understanding the molecular basis of ferritin-related disorders such as neuroferritinopathy in which the 24-meric structure with 432 symmetry is distorted.

Exposure to toxic Alexandrium minutum activates the detoxifying and antioxidant systems in gills of the oyster Crassostrea gigas

Harmful algal blooms of Alexandrium spp. dinoflagellates regularly occur in French coastal waters contaminating shellfish. Studies have demonstrated that toxic Alexandrium spp. disrupt behavioural and physiological processes in marine filter-feeders, but molecular modifications triggered by phycotoxins are less well understood. This study analyzed the mRNA levels of 7 genes encoding antioxidant/detoxifying enzymes in gills of Pacific oysters (Crassostrea gigas) exposed to a cultured, toxic strain of A. minutum, a producer of paralytic shellfish toxins (PST) or fed Tisochrysis lutea (T. lutea, formerly Isochrysis sp., clone Tahitian (T. iso)), a non-toxic control diet, in four repeated experiments. Transcript levels of sigma-class glutathione S-transferase (GST), glutathione reductase (GR) and ferritin (Fer) were significantly higher in oysters exposed to A. minutum compared to oysters fed T. lutea. The detoxification pathway based upon glutathione (GSH)-conjugation of toxic compounds (phase II) is likely activated, and catalyzed by GST. This system appeared to be activated in gills probably for the detoxification of PST and/or extra-cellular compounds, produced by A. minutum. GST, GR and Fer can also contribute to antioxidant functions to prevent cellular damage from increased reactive oxygen species (ROS) originating either from A. minutum cells directly, from oyster hemocytes during immune response, or from other gill cells as by-products of detoxification.

Iron oxides in human spleen

Iron is an essential element for fundamental cell functions and a catalyst for chemical reactions. Three samples extracted from the human spleen were investigated by scanning (SEM) and transmission electron microscopy (TEM), Mössbauer spectrometry (MS), and SQUID magnetometry. The sample with diagnosis of hemosiderosis (H) differs from that referring to hereditary spherocytosis and the reference sample. SEM reveals iron-rich micrometer-sized aggregate of various structures-tiny fibrils in hereditary spherocytosis sample and no fibrils in hemochromatosis. Hematite and magnetite particles from 2 to 6 μm in TEM with diffraction in all samples were shown. The SQUID magnetometry shows different amount of diamagnetic, paramagnetic and ferrimagnetic structures in the tissues. The MS results indicate contribution of ferromagnetically split sextets for all investigated samples. Their occurrence indicates that at least part of the sample is magnetically ordered below the critical temperature. The iron accumulation process is different in hereditary spherocytosis and hemosiderosis. This fact may be the reason of different iron crystallization.

Oxidative stress and the homeodynamics of iron metabolism

Iron and oxygen share a delicate partnership since both are indispensable for survival, but if the partnership becomes inadequate, this may rapidly terminate life. Virtually all cell components are directly or indirectly affected by cellular iron metabolism, which represents a complex, redox-based machinery that is controlled by, and essential to, metabolic requirements. Under conditions of increased oxidative stress—i.e., enhanced formation of reactive oxygen species (ROS)—however, this machinery may turn into a potential threat, the continued requirement for iron promoting adverse reactions such as the iron/H2O2-based formation of hydroxyl radicals, which exacerbate the initial pro-oxidant condition. This review will discuss the multifaceted homeodynamics of cellular iron management under normal conditions as well as in the context of oxidative stress.

Parameters influencing in-hospital mortality in patients hospitalized in intensive cardiac care unit: is there an influence of anemia and iron deficiency?

We investigated the incidence and prognostic value of anemia as well as of the iron status in non-selected patients admitted to an intensive cardiac care unit (ICCU). 392 patients (mean age 70 ± 13.8 years, 43% women), 168 with acute coronary syndromes (ACS), 122 with acute decompensated heart failure, and 102 with other acute cardiac disorders were consecutively, prospectively assessed. The biomarkers of iron status-serum iron concentration (SIC), total iron binding capacity (TIBC), and transferrin saturation (TSAT) together with standard clinical, biochemical and echocardiographic variables-were analyzed. In-hospital mortality was 3.8% (15 patients). The prevalences of anemia (according to WHO criteria), and iron deficiency (ID) were 64 and 63%, respectively. The level of biomarkers of iron status, but not anemia, was lower in patients who died (p < 0.05). Anemia was less frequent in patients with ACS as compared to the remaining ICCU population (p = 0.019). The analysis by logistic regression indicated the highest risk of death for age [odds ratio (OD) 1.38, 95% CI 1.27-1.55], SIC (OR 0.85, 95% CI 0.78-0.94), TIBC (OR 0.95, 95% CI 0.91-0.98), left ventricle ejection fraction (OR 0.85, 95% CI 0.77-0.93), as well as hospitalization for non-ACS (OR 0.25, 95% CI 0.14-0.46), (p < 0.05). The risk of death during hospitalization tended to increase with decreasing levels of TIBC (p = 0.49), as well as with the absence of ACS (p = 0.54). The incidence of anemia and ID in heterogeneous ICCU patients is high. Parameters of the iron status, but not anemia per se, independently influence in-hospital mortality. The prevalence of anemia is higher in non-ACS patients, and tends to worsen the prognosis.

Synthesis of homogeneous protein-stabilized rutin nanodispersions by reversible assembly of soybean (Glycine max) seed ferritin

We have studied the soybean seed ferritin stabilized rutin nanodispersions with improved water-solubility, thermal stability, and UV radiation stability.

Elevated serum ferritin and mercury concentrations are associated with hypertension; analysis of the fourth and fifth Korea national health and nutrition examination survey (KNHANES IV-2, 3, 2008-2009 and V-1, 2010)

The impact of simultaneously elevated serum ferritin and mercury concentrations on hypertension in the general population is not known. To determine the association of serum ferritin and mercury concentrations with hypertension, 6213 subjects (3060 men and 3153 women) over 20 years of age from 2008 to 2010 Korea National Health and Nutrition Examination Survey were divided into tertiles according to serum ferritin and mercury concentrations in each gender. Serum ferritin (258.2 vs. 94.8 pmol/L) and mercury concentrations (28.4 vs. 19.9 nmol/L) were higher in men than in women. Serum ferritin (men; P = 0.029, women; P < 0.001) and mercury (men; P < 0.001, women; P = 0.003) concentrations were significantly associated with the prevalence of hypertension. In addition, significant correlation between serum ferritin and mercury concentrations in both men (r = 0.193, P < 0.001) and women (r = 0.145, P < 0.001) were found. Also, the increase of serum ferritin concentrations were more prominent in men (P < 0.001) than in women (P = 0.017) as the serum mercury tertiles increased after proper adjustments. Furthermore, significantly higher odds ratios of hypertension were found in the second (OR = 1.86, 95% CI; 1.05-3.30), and third (OR = 1.84, 95% CI; 1.01-3.36) tertiles of serum ferritin with the top tertile of serum mercury in men. The current study indicate that serum ferritin and mercury concentrations are associated with the prevalence of hypertension and that simultaneously elevated serum ferritin and mercury concentrations are related to the risk for hypertension in men.

Phosphoproteomic analysis of the resistant and susceptible genotypes of maize infected with sugarcane mosaic virus

Protein phosphorylation plays a pivotal role in the regulation of many cellular events. No information is yet available, however, on protein phosphorylation in plants in response to virus infection. In this study, we characterized phosphoproteomes of resistant and susceptible genotypes of maize (Zea mays L.) in response to Sugarcane mosaic virus (SCMV) infection. Based on isotope tags for relative and absolute quantification technology, TiO2 enrichment method and LC-MS/MS analysis, we identified 65 and 59 phosphoproteins respectively, whose phosphorylation level regulated significantly in susceptible and resistant plants. Some identified phosphoproteins were shared by both genotypes, suggesting a partial overlapping of the responsive pathways to virus infection. While several phosphoproteins are well-known pathogen response phosphoproteins, virus infection differentially regulates most other phosphoproteins, which has not been reported in literature. Changes in protein phosphorylation status indicated that response to SCMV infection encompass a reformatting of major cellular processes. Our data provide new valuable insights into plant-virus interactions.

Hepatic oxidative status and metal homeostasis disturbance of 2-hydroxylated dioxin in ICR mice

In the present study, the toxic effects of the oral exposure of 2-hydroxylated dioxin (2-HODD) in ICR male mice were examined. The mice were administered different doses (0.2, 2.0 and 20.0mg/kg) of 2-HODD. After 14 days of exposure, the oxidative stress (OS) indicator levels and the essential metal concentrations in the mouse livers were determined. The results showed that the superoxide dismutase (SOD) and the glutathione peroxidase (GPx) activities were increased in the 0.2mg/kg group, whereas they were significantly decreased in the 2.0 and 20.0mg/kg groups. Decreases in the catalase (CAT) activity and the glutathione (GSH) levels, accompanied by increases in the malondialdehyde (MDA) contents, were recorded in all of the 2-HODD-treated groups. The hepatic iron, copper and zinc levels increased in all of the 2-HODD-treated groups. The histological examination of the livers demonstrated swollen cells and inflammation. Dose-dependent changes in both the OS indicators and the hepatic metal levels were observed. In conclusion, a single low dose of 2-HODD significantly perturbed the hepatic OS status and metals homeostasis in the mice.

Redox proteomics as biomarker for assessing the biological effects of contaminants in crayfish from Doñana National Park

Despite its environmental relevance and sensitivity, Doñana National Park (DNP) is under high ecological pressure. In crayfish (Procambarus clarkii), the utility of redox proteomics as a novel biomarker was evaluated in the aquatic ecosystems of DNP and its surroundings, where agricultural activity is a serious concern. After fluorescence labeling of reversibly oxidized Cys and 2-DE separation, the total density of proteins with reversibly oxidized thiols was found to be much higher in animals from the Matochal (MAT) and Rocina (ROC) streams, while no difference was found in crayfish from Partido (PAR) stream compared to those from the DNP core at Lucio del Palacio (the negative control). The 2-DE analysis revealed 35 spots with significant differences in thiol oxidation, among which 19 proteins were identified via MALDI-TOF/TOF. While 3 spots, identified as ferritin, showed higher oxidation levels in ROC, other identified proteins were more intense at MAT than at ROC (superoxide dismutase, protein disulfide isomerase and actin) or were overoxidized only in MAT (nucleoside diphosphate kinase, fructose-biphosphate aldolase, fatty acid-binding protein, phosphopyruvate hydratase). For most of the identified proteins, spots corresponding to different Cys oxidized forms were detected, and the native forms, without oxidized thiol groups were also found in some of them. Evidence of reversible oxidation was found for specific Cys residues, including Cys13 in ferritin as well as Cys76 and Cys108 in nucleoside diphosphate kinase. The identified thiol-oxidized proteins provide information about the metabolic pathways and/or physiological processes affected by pollutant-elicited oxidative stress.

Deferoxamine reduces neuronal death and hematoma lysis after intracerebral hemorrhage in aged rats

Intracerebral hemorrhage (ICH) is primarily a disease of the elderly. Deferoxamine (DFX), an iron chelator, reduces long-term neurological deficits and brain atrophy after ICH in aged rats. In the present study, we investigated whether DFX can reduce acute ICH-induced neuronal death and whether it affects the endogenous response to ICH (ferritin upregulation and hematoma resolution) in aged rats. Male Fischer 344 rats (18 months old) had an intracaudate injection of 100 μL autologous whole blood into the right basal ganglia and were treated with DFX (100 mg/kg) or vehicle 2 hours post-ICH and then every 12 hours up to 7 days. Rats were euthanized 1, 3, or 7 days later for neuronal death, ferritin and hematoma size measurements. Plasma ferritin levels and behavioral outcome following ICH were also examined. DFX treatment significantly reduced ICH-induced neuronal death and neurological deficits. DFX also suppressed ferritin upregulation in the ipsilateral basal ganglia after ICH and hematoma lysis (hematoma volume at day 7: 13.2±4.9 vs. 3.8±1.2 mm3 in vehicle-treated group, p<0.01). However, effects of DFX on plasma ferritin levels after ICH did not reach significance. In conclusion, DFX reduces neuronal death and neurological deficits after ICH in aged rats. It also affects the endogenous response to ICH.

Iron at the interface of immunity and infection

Both, mammalian cells and microbes have an essential need for iron, which is required for many metabolic processes and for microbial pathogenicity. In addition, cross-regulatory interactions between iron homeostasis and immune function are evident. Cytokines and the acute phase protein hepcidin affect iron homeostasis leading to the retention of the metal within macrophages and hypoferremia. This is considered to result from a defense mechanism of the body to limit the availability of iron for extracellular pathogens while on the other hand the reduction of circulating iron results in the development of anemia of inflammation. Opposite, iron and the erythropoiesis inducing hormone erythropoietin affect innate immune responses by influencing interferon-gamma (IFN-γ) mediated (iron) or NF-kB inducible (erythropoietin) immune effector pathways in macrophages. Thus, macrophages loaded with iron lose their ability to kill intracellular pathogens via IFN-γ mediated effector pathways such as nitric oxide (NO) formation. Accordingly, macrophages invaded by the intracellular bacterium Salmonella enterica serovar Typhimurium increase the expression of the iron export protein ferroportin thereby reducing the availability of iron for intramacrophage bacteria while on the other side strengthening anti-microbial macrophage effector pathways via increased formation of NO or TNF-α. In addition, certain innate resistance genes such as natural resistance associated macrophage protein function (Nramp1) or lipocalin-2 exert part of their antimicrobial activity by controlling host and/or microbial iron homeostasis. Consequently, pharmacological or dietary modification of cellular iron trafficking enhances host resistance to intracellular pathogens but may increase susceptibility to microbes in the extracellular compartment and vice versa. Thus, the control over iron homeostasis is a central battlefield in host–pathogen interplay influencing the course of an infectious disease in favor of either the mammalian host or the pathogenic invader.

Novel functional changes during podocyte differentiation: increase of oxidative resistance and H-ferritin expression

Podocytes are highly specialized, arborized epithelial cells covering the outer surface of the glomerular tuft in the kidney. Terminally differentiated podocytes are unable to go through cell division and hereby they are lacking a key property for regeneration after a toxic injury. Podocytes are long-lived cells but, to date, little is known about the mechanisms that support their stress resistance. Our aim was to investigate whether the well-known morphological changes during podocyte differentiation are accompanied by changes in oxidative resistance in a manner that could support their long-term survival. We used a conditionally immortalized human podocyte cell line to study the morphological and functional changes during differentiation. We followed the differentiation process for 14 days by time-lapse microscopy. During this period nondifferentiated podocytes gradually transformed into large, nonproliferating, frequently multinucleated cells, with enlarged nuclei and opened chromatin structure. We observed that differentiated podocytes were highly resistant to oxidants such as H₂O₂ and heme when applied separately or in combination, whereas undifferentiated cells were prone to such challenges. Elevated oxidative resistance of differentiated podocytes was associated with increased activities of antioxidant enzymes and H-ferritin expression. Immunohistochemical analysis of normal human kidney specimens revealed that podocytes highly express H-ferritin in vivo as well.

Iron metabolism disturbance in a French cohort of ALS patients

OBJECTIVE

The aim of this study was to assess iron status in a cohort of amyotrophic lateral sclerosis (ALS) patients compared to controls in order to evaluate these parameters as a risk factor or a modifying factor of ALS.

METHODS

We collected serum iron, ferritin, transferrin, total iron-binding capacity, and transferrin saturation coefficient (TSC) from 104 ALS patients at the time of diagnosis and from 145 controls. We reported phenotypic characteristics and evolution parameters such as ALSFRS-R and forced vital capacity at diagnosis and after one year of follow-up. In a first step we compared iron status between ALS patients and controls, and then we evaluated the relation between iron status and disease evolution of ALS patients using univariate and multivariate analysis.

RESULTS

We observed increased concentrations of serum iron (P = 0.002) and ferritin (P < 0.0001) and increased TSC (P = 0.017) in ALS patients. We also showed an association between markers of iron status and high body weight loss in ALS patients. The multivariate analysis of survival highlighted a significant relation between ferritin level and disease duration (P = 0.038).

CONCLUSION

This is the first study showing a higher concentration of serum iron in ALS patients, strengthening the involvement of a deregulation of iron metabolism in ALS.

An adequate Fe nutritional status of maize suppresses infection and biotrophic growth of Colletotrichum graminicola

Iron (Fe) is an essential element for plant pathogens as well as for their host plants. As Fe plays a central role in pathogen virulence, most plants have evolved Fe-withholding strategies to reduce Fe availability to pathogens. On the other hand, plants need Fe for an oxidative burst in their basal defense response against pathogens. To investigate how the plant Fe nutritional status affects plant tolerance to a hemibiotrophic fungal pathogen, we employed the maize-Colletotrichum graminicola pathosystem. Fungal infection progressed rapidly via biotrophic to necrotrophic growth in Fe-deficient leaves, while an adequate Fe nutritional status suppressed the formation of infection structures of C. graminicola already during the early biotrophic growth phase. As indicated by Prussian blue and 3,3'-diaminobenzidine (DAB) staining, the retarding effect of an adequate Fe nutritional status on fungal development coincided temporally and spatially with the recruitment of Fe to infection sites and a local production of H2 O2 . A similar coincidence between local Fe and H2 O2 accumulation was found in a parallel approach employing C. graminicola mutants affected in Fe acquisition and differing in virulence. These results indicate that an adequate Fe nutritional status delays and partially suppresses the fungal infection process and the biotrophic growth phase of C. graminicola, most likely via the recruitment of free Fe to the fungal infection site for a timely oxidative burst.

Iron overload in Plasmodium berghei-infected placenta as a pathogenesis mechanism of fetal death

Plasmodium infection during gestation may lead to severe clinical manifestations including abortion, stillbirth, intrauterine growth retardation, and low birth weight. Mechanisms underlying such poor pregnancy outcomes are still unclear. In the animal model of severe placental malaria (PM), in utero fetal death frequently occurs and mothers often succumb to infection before or immediately after delivery. Plasmodium berghei-infected erythrocytes (IEs) continuously accumulate in the placenta, where they are then phagocytosed by fetal-derived placental cells, namely trophoblasts. Inside the phagosomes, disruption of IEs leads to the release of non-hemoglobin bound heme, which is subsequently catabolized by heme oxygenase-1 into carbon monoxide, biliverdin, and labile iron. Fine-tuned regulatory mechanisms operate to maintain iron homeostasis, preventing the deleterious effect of iron-induced oxidative stress. Our preliminary results demonstrate that iron overload in trophoblasts of P. berghei-infected placenta is associated with fetal death. Placentas which supported normally developing embryos showed no iron accumulation within the trophoblasts. Placentas from dead fetuses showed massive iron accumulation, which was associated with parasitic burden. Here we present preliminary data suggesting that disruption of iron homeostasis in trophoblasts during the course of PM is a consequence of heme accumulation after intense IE engulfment. We propose that iron overload in placenta is a pathogenic component of PM, contributing to fetal death. The mechanism through which it operates still needs to be elucidated.

Heme exporter FLVCR1a regulates heme synthesis and degradation and controls activity of cytochromes P450

BACKGROUND & AIMS

The liver has one of the highest rates of heme synthesis of any organ. More than 50% of the heme synthesized in the liver is used for synthesis of P450 enzymes, which metabolize exogenous and endogenous compounds that include natural products, hormones, drugs, and carcinogens. Feline leukemia virus subgroup C cellular receptor 1a (FLVCR1a) is plasma membrane heme exporter that is ubiquitously expressed and controls intracellular heme content in hematopoietic lineages. We investigated the role of Flvcr1a in liver function in mice.

METHODS

We created mice with conditional disruption of Mfsd7b, which encodes Flvcr1a, in hepatocytes (Flvcr1a(fl/fl);alb-cre mice). Mice were analyzed under basal conditions, after phenylhydrazine-induced hemolysis, and after induction of cytochromes P450 synthesis. Livers were collected and analyzed by histologic, quantitative real-time polymerase chain reaction, and immunoblot analyses. Hepatic P450 enzymatic activities were measured.

RESULTS

Flvcr1a(fl/fl);alb-cre mice accumulated heme and iron in liver despite up-regulation of heme oxygenase 1, ferroportin, and ferritins. Hepatic heme export activity of Flvcr1a was closely associated with heme biosynthesis, which is required to sustain cytochrome induction. Upon cytochromes P450 stimulation, Flvcr1a(fl/fl);alb-cre mice had reduced cytochrome activity, associated with accumulation of heme in hepatocytes. The expansion of the cytosolic heme pool in these mice was likely responsible for the early inhibition of heme synthesis and increased degradation of heme, which reduced expression and activity of cytochromes P450.

CONCLUSIONS

In livers of mice, Flvcr1a maintains a free heme pool that regulates heme synthesis and degradation as well as cytochromes P450 expression and activity. These findings have important implications for drug metabolism.

H-ferritin ferroxidase induces cytoprotective pathways and inhibits microvascular stasis in transgenic sickle mice

Hemolysis, oxidative stress, inflammation, vaso-occlusion, and organ infarction are hallmarks of sickle cell disease (SCD). We have previously shown that increases in heme oxygenase-1 (HO-1) activity detoxify heme and inhibit vaso-occlusion in transgenic mouse models of SCD. HO-1 releases Fe(2+) from heme, and the ferritin heavy chain (FHC) ferroxidase oxidizes Fe(2+) to catalytically inactive Fe(3+) inside ferritin. FHC overexpression has been shown to be cytoprotective. In this study, we hypothesized that overexpression of FHC and its ferroxidase activity will inhibit inflammation and microvascular stasis in transgenic SCD mice in response to plasma hemoglobin. We utilized a Sleeping Beauty (SB) transposase plasmid to deliver a human wild-type-ferritin heavy chain (wt-hFHC) transposable element by hydrodynamic tail vein injections into NY1DD SCD mice. Control SCD mice were infused with the same volume of lactated Ringer's solution (LRS) or a human triple missense FHC (ms-hFHC) plasmid with no ferroxidase activity. 8 weeks later, LRS-injected mice had ~40% microvascular stasis (% non-flowing venules) 1 h after infusion of stroma-free hemoglobin, while mice overexpressing wt-hFHC had only 5% stasis (p < 0.05), and ms-hFHC mice had 33% stasis suggesting vascular protection by ferroxidase active wt-hFHC. The wt-hFHC SCD mice had marked increases in splenic hFHC mRNA and hepatic hFHC protein, ferritin light chain (FLC), 5-aminolevulinic acid synthase (ALAS), heme content, ferroportin, nuclear factor erythroid 2-related factor 2 (Nrf2), and HO-1 activity and protein. There was also a decrease in hepatic activated nuclear factor-kappa B (NF-κB) phospho-p65 and vascular cell adhesion molecule-1 (VCAM-1). Inhibition of HO-1 activity with tin protoporphyrin demonstrated HO-1 was not essential for the protection by wt-hFHC. We conclude that wt-hFHC ferroxidase activity enhances cytoprotective Nrf2-regulated proteins including HO-1, thereby resulting in decreased NF-κB-activation, adhesion molecules, and microvascular stasis in transgenic SCD mice.

Coupling heme and iron metabolism via ferritin H chain

SIGNIFICANCE

Inflammation and immunity can be associated with varying degrees of heme release from hemoproteins, eventually leading to cellular and tissue iron (Fe) overload, oxidative stress, and tissue damage. Presumably, these deleterious effects contribute to the pathogenesis of systemic infections.

RECENT ADVANCES

Heme release from hemoglobin sensitizes parenchyma cells to undergo programmed cell death in response to proinflammatory cytokines, such as tumor necrosis factor. This cytotoxic effect is driven by a mechanism involving intracellular accumulation of free radicals, which sustain the activation of the c-Jun N-terminal kinase (JNK) signaling transduction pathway. While heme catabolism by heme oxygenase-1 (HO-1) prevents programmed cell death, this cytoprotective effect requires the co-expression of ferritin H (heart/heavy) chain (FTH), which controls the pro-oxidant effect of labile Fe released from the protoporphyrin IX ring of heme. This antioxidant effect of FTH restrains JNK activation, whereas JNK activation inhibits FTH expression, a cross talk that controls metabolic adaptation to cellular Fe overload associated with systemic infections.

CRITICAL ISSUES AND FUTURE DIRECTIONS

Identification and characterization of the mechanisms via which FTH provides metabolic adaptation to tissue Fe overload should provide valuable information to our current understanding of the pathogenesis of systemic infections as well as other immune-mediated inflammatory diseases.

Biotrophy-specific downregulation of siderophore biosynthesis in Colletotrichum graminicola is required for modulation of immune responses of maize

The hemibiotrophic maize pathogen Colletotrichum graminicola synthesizes one intracellular and three secreted siderophores. eGFP fusions with the key siderophore biosynthesis gene, SID1, encoding l-ornithine-N(5) -monooxygenase, suggested that siderophore biosynthesis is rigorously downregulated specifically during biotrophic development. In order to investigate the role of siderophores during vegetative development and pathogenesis, SID1, which is required for synthesis of all siderophores, and the non-ribosomal peptide synthetase gene NPS6, synthesizing secreted siderophores, were deleted. Mutant analyses revealed that siderophores are required for vegetative growth under iron-limiting conditions, conidiation, ROS tolerance, and cell wall integrity. Δsid1 and Δnps6 mutants were hampered in formation of melanized appressoria and impaired in virulence. In agreement with biotrophy-specific downregulation of siderophore biosynthesis, Δsid1 and Δnps6 strains were not affected in biotrophic development, but spread of necrotrophic hyphae was reduced. To address the question why siderophore biosynthesis is specifically downregulated in biotrophic hyphae, maize leaves were infiltrated with siderophores. Siderophore infiltration alone did not induce defence responses, but formation of biotrophic hyphae in siderophore-infiltrated leaves caused dramatically increased ROS formation and transcriptional activation of genes encoding defence-related peroxidases and PR proteins. These data suggest that fungal siderophores modulate the plant immune system.

A paper-based calorimetric microfluidics platform for bio-chemical sensing

In this report, a paper-based micro-calorimetric biochemical detection method is presented. Calorimetric detection of biochemical reactions is demonstrated as an extension of current colorimetric and electrochemical detection mechanisms of paper-based biochemical analytical systems. Reaction and/or binding temperature of glucose/glucose oxidase, DNA/hydrogen peroxide, and biotin/streptavidin, are measured by the paper-based micro-calorimeter. Commercially available glucose calibration samples of 0.05, 0.15 and 0.3% wt/vol concentration are used for comparing the device performance with a commercially available glucose meter (electrochemical detection). The calorimetric glucose detection demonstrates a measurement error less than 2%. The calorimetric detection results of DNA concentrations from 0.9 to 7.3 mg/mL and temperature changes in biotin and streptavidin reaction are presented to demonstrate the feasibility of integrating the calorimetric detection method with paper based microfluidic devices.

[Oxidative stress in the of alcoholic liver disease]

Parameters reflecting oxidative stress (OS) have been studied in 37 patients with alcoholic liver disease (ALD) during admission to the hospital and 2 weeks after the beginning of therapy. The patients were divided into 3 groups: alcoholic hepatitis (AH), alcoholic cirrhosis with hepatic insufficiency (the group C with Child-Paquet) and terminal stage patients (they subsequently died). All patients were characterized by a significant increase in plasma products of lipid peroxidation (conjugated diene and malondialdehyde) and decrease of the ceruloplasmin level. The coefficient K OS significantly exceeded normal values both on admission and after the 2-week course of traditional treatment. This suggests an important role of the OS with ALD.

Role of intracellular labile iron, ferritin, and antioxidant defence in resistance of chronically adapted Jurkat T cells to hydrogen peroxide

To examine the role of intracellular labile iron pool (LIP), ferritin (Ft), and antioxidant defence in cellular resistance to oxidative stress on chronic adaptation, a new H2O2-resistant Jurkat T cell line "HJ16" was developed by gradual adaptation of parental "J16" cells to high concentrations of H2O2. Compared to J16 cells, HJ16 cells exhibited much higher resistance to H2O2-induced oxidative damage and necrotic cell death (up to 3mM) and had enhanced antioxidant defence in the form of significantly higher intracellular glutathione and mitochondrial ferritin (FtMt) levels as well as higher glutathione-peroxidase (GPx) activity. In contrast, the level of the Ft H-subunit (FtH) in the H2O2-adapted cell line was found to be 7-fold lower than in the parental J16 cell line. While H2O2 concentrations higher than 0.1mM fully depleted the glutathione content of J16 cells, in HJ16 cells the same treatments decreased the cellular glutathione content to only half of the original value. In HJ16 cells, H2O2 concentrations higher than 0.1mM increased the level of FtMt up to 4-fold of their control values but had no effect on the FtMt levels in J16 cells. Furthermore, while the basal cytosolic level of LIP was similar in both cell lines, H2O2 treatment substantially increased the cytosolic LIP levels in J16 but not in HJ16 cells. H2O2 treatment also substantially decreased the FtH levels in J16 cells (up to 70% of the control value). In contrast in HJ16 cells, FtH levels were not affected by H2O2 treatment. These results indicate that chronic adaptation of J16 cells to high concentrations of H2O2 has provoked a series of novel and specific cellular adaptive responses that contribute to higher resistance of HJ16 cells to oxidative damage and cell death. These include increased cellular antioxidant defence in the form of higher glutathione and FtMt levels, higher GPx activity, and lower FtH levels. Further adaptive responses include the significantly reduced cellular response to oxidant-mediated glutathione depletion, FtH modulation, and labile iron release and a significant increase in FtMt levels following H2O2 treatment.

Mitochondrial ferritin in the regulation of brain iron homeostasis and neurodegenerative diseases

Mitochondrial ferritin (FtMt) is a novel iron-storage protein in mitochondria. Evidences have shown that FtMt is structurally and functionally similar to the cytosolic H-chain ferritin. It protects mitochondria from iron-induced oxidative damage presumably through sequestration of potentially harmful excess free iron. It also participates in the regulation of iron distribution between cytosol and mitochondrial contents. Unlike the ubiquitously expressed H-ferritin, FtMt is mainly expressed in testis and brain, which suggests its tissue-related roles. FtMt is involved in pathogenesis of neurodegenerative diseases, as its increased expression has been observed in Alzheimer’s disease, restless legs syndrome and Friedreich’s ataxia. Studies from our laboratory showed that in Alzheimer’s disease, FtMt overexpression attenuated the β-amyloid induced neurotoxicity, which on the other hand increased significantly when FtMt expression was knocked down. It is also found that, by maintaining mitochondrial iron homeostasis, FtMt could prevent 6-hydroxydopamine induced dopaminergic cell damage in Parkinson’s disease. These recent findings on FtMt regarding its functions in regulation of brain iron homeostasis and its protective role in pathogenesis of neurodegenerative diseases are summarized and reviewed.

Iron availability is increased in individual human ovarian follicles in close proximity to an endometrioma compared with distal ones

STUDY QUESTION

Does the iron content of an endometrioma represent a potential source of toxicity for the adjacent follicles?

SUMMARY ANSWER

The presence of an endometrioma increases iron and H/L ferritin levels, and transferrin receptor (TfR1) mRNA in individual follicles proximal to the endometrioma and is accompanied by reduced oocyte retrieval.

WHAT IS KNOWN ALREADY

Levels of free iron in endometriotic ovarian cysts are much higher than those in normal serum or in non-endometriotic ovarian cysts. The presence of an endometrioma exerts a detrimental effect on the surrounding healthy ovarian tissue as reflected by a reduced number of developing follicles and oocytes retrieved in IVF cycles.

STUDY DESIGN, SIZE, DURATION

This is a research study with prospective collection and evaluation of individual follicles (follicular fluid and luteinized granulosa cells) from the affected and the healthy ovaries of 13 women with unilateral endometrioma.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Individual follicular samples (145) were obtained from 13 women with endometriosis-related infertility undergoing IVF-ICSI procedures from May 2012 to March 2013. All women had unilateral endometrioma not previously treated with surgery; the contralateral ovary was free of endometriomas and previous surgery. The average ± SEM age was 35.36 ± 2.5 years with anti-Mullerian hormone levels of 2.03 ± 0.55 ng/ml. Follicles were classified as: (i) proximal follicles, in physical contact with the endometrioma; (ii) distal follicles, present in the affected ovary but not in close contact with the endometrioma and (iii) contralateral follicles, in the contralateral healthy ovary. Iron content was measured by the FerroZine method. H/L ferritin subunits were evaluated by specific enzyme-linked immunosorbant assays. Expression of H ferritin and TfR1 was examined by semi-quantitative RT-PCR. Oocyte retrieval rates and Day 3 embryo quality were analyzed.

MAIN RESULTS AND THE ROLE OF CHANCE

Total iron levels were higher in endometrioma-proximal follicles compared with endometrioma-distal ones (P = 0.009) and to follicles in the healthy ovary (P = 0.02). L ferritin was higher in proximal versus distal follicles (P = 0.044) or follicles from the healthy ovary (P = 0.027). H ferritin was higher in the proximal and distal follicles compared with follicles in the healthy ovary (P = 0.042 and P = 0.0067, respectively). H ferritin transcript levels in granulosa cells were higher in proximal follicles versus follicles from healthy ovary (P = 0.02). TfR1 transcript levels were higher in proximal versus distal follicles (P = 0.03) and versus follicles from the healthy ovary (P = 0.04). The oocyte retrieval rate was lower in proximal and distal follicles than in follicles from the healthy ovary (P = 0.001 and P = 0.04, respectively).

LIMITATIONS, REASONS FOR CAUTION

This is a study on a relatively small sample size and confirmation in a larger group of patients may be required. The method used to purify luteinized granulosa cells offers the best combination of purity, viability and total number of cells recovered. However, a minor contamination by CD45(+) cells (<5%) cannot be excluded.

WIDER IMPLICATIONS OF THE FINDINGS

This study represents a further in-depth analysis of the toxic influence of the endometrioma content on the surrounding follicles. We demonstrate the presence of iron-related compounds that are potentially toxic to developing ovarian follicles adjacent to the endometrioma during IVF. Our findings provide novel information that suggests that when surgical removal of the endometrioma is not the option, follicle aspiration at sites distant from the endometrioma might increase the probability of retrieving oocytes.

STUDY FUNDING/COMPETING INTEREST(S)

This project was supported by Fondazione Giorgio Pardi, Milan, Italy. The authors have no competing financial interests in relation to the content of this research paper.

TRIAL REGISTRATION NUMBER

NA.

Glycol-split nonanticoagulant heparins are inhibitors of hepcidin expression in vitro and in vivo

Hepcidin controls systemic iron availability, and its excess contributes to the anemia of chronic diseases, the most prevalent anemia in hospitalized patients. We previously reported that heparins are efficient hepcidin inhibitors both in vitro and in vivo, but their anticoagulant activity limits therapeutic use. We studied nonanticoagulant heparins produced by N-acetylation and oxidation/reduction (glycol-split) that lost antithrombin-binding affinity. Four nonanticoagulant heparins inhibited hepcidin expression in hepatic HepG2 cells and primary hepatocytes. The 2 most potent ones used in mice suppressed liver hepcidin expression and serum hepcidin in 6 hours, with a significant decrease of spleen iron. This occurred also in lipopolysaccharide (LPS)-treated animals that mimic inflammation, as well as after chronic 1-week treatments, without evident adverse effects on coagulation. Heparin injections increased iron mobilization and facilitated the recovery from the anemia induced by heat-killed Brucella abortus, a model of inflammatory anemia. The heparins were used also in Bmp6(-/-) mice. A single dose of heparin reduced the already low level of hepcidin of these mice and prevented its induction by LPS. These nonanticoagulant compounds impair bone morphogenetic protein /sons of mothers against decapentaplegic signaling with no evident adverse effect in vivo, even when administered chronically. They may offer a strategy for the treatment of diseases with high hepcidin levels.

Phytoagents for cancer management: regulation of nucleic acid oxidation, ROS, and related mechanisms

Accumulation of oxidized nucleic acids causes genomic instability leading to senescence, apoptosis, and tumorigenesis. Phytoagents are known to reduce the risk of cancer development; whether such effects are through regulating the extent of nucleic acid oxidation remains unclear. Here, we outlined the role of reactive oxygen species in nucleic acid oxidation as a driving force in cancer progression. The consequential relationship between genome instability and cancer progression highlights the importance of modulation of cellular redox level in cancer management. Current epidemiological and experimental evidence demonstrate the effects and modes of action of phytoagents in nucleic acid oxidation and provide rationales for the use of phytoagents as chemopreventive or therapeutic agents. Vitamins and various phytoagents antagonize carcinogen-triggered oxidative stress by scavenging free radicals and/or activating endogenous defence systems such as Nrf2-regulated antioxidant genes or pathways. Moreover, metal ion chelation by phytoagents helps to attenuate oxidative DNA damage caused by transition metal ions. Besides, the prooxidant effects of some phytoagents pose selective cytotoxicity on cancer cells and shed light on a new strategy of cancer therapy. The “double-edged sword” role of phytoagents as redox regulators in nucleic acid oxidation and their possible roles in cancer prevention or therapy are discussed in this review.

Iron and intracerebral hemorrhage: from mechanism to translation

Intracerebral hemorrhage (ICH) is a leading cause of morbidity and mortality around the world. Currently, there is no effective medical treatment available to improve functional outcomes in patients with ICH due to its unknown mechanisms of damage. Increasing evidence has shown that the metabolic products of erythrocytes are the key contributor of ICH-induced secondary brain injury. Iron, an important metabolic product that accumulates in the brain parenchyma, has a detrimental effect on secondary injury following ICH. Because the damage mechanism of iron during ICH-induced secondary injury is clear, iron removal therapy research on animal models is effective. Although many animal and clinical studies have been conducted, the exact metabolic pathways of iron and the mechanisms of iron removal treatments are still not clear. This review summarizes recent progress concerning the iron metabolism mechanisms underlying ICH-induced injury. We focus on iron, brain iron metabolism, the role of iron in oxidative injury, and iron removal therapy following ICH, and we suggest that further studies focus on brain iron metabolism after ICH and the mechanism for iron removal therapy.

Multiple sclerosis: molecular mechanisms and therapeutic opportunities

The pathophysiology of multiple sclerosis (MS) involves several components: redox, inflammatory/autoimmune, vascular, and neurodegenerative. All of them are supported by the intertwined lines of evidence, and none of them should be written off. However, the exact mechanisms of MS initiation, its development, and progression are still elusive, despite the impressive pace by which the data on MS are accumulating. In this review, we will try to integrate the current facts and concepts, focusing on the role of redox changes and various reactive species in MS. Knowing the schedule of initial changes in pathogenic factors and the key turning points, as well as understanding the redox processes involved in MS pathogenesis is the way to enable MS prevention, early treatment, and the development of therapies that target specific pathophysiological components of the heterogeneous mechanisms of MS, which could alleviate the symptoms and hopefully stop MS. Pertinent to this, we will outline (i) redox processes involved in MS initiation; (ii) the role of reactive species in inflammation; (iii) prooxidative changes responsible for neurodegeneration; and (iv) the potential of antioxidative therapy.

Differential response of two ferritin subunit genes (VpFer1 and VpFer2) from Venerupis philippinarum following pathogen and heavy metals challenge

As a principal extracellular iron storage molecule, ferritin plays an important role in the iron-withholding strategy of innate immunity and detoxification system. In this study, we cloned and characterized another ferritin from Venerupis philippinarum (designated as VpFer2), in addition to one previously reported (VpFer1). VpFer2 possessed all the conserved features critical for the fundamental structure and function of ferritin H subunit. VpFer1 and VpFer2 mRNA were both found to be most abundantly expressed in hepatopancreas. Vibrio challenge could significantly up-regulate the mRNA expression of VpFers, and VpFer2 showed more sensitive to Vibrio anguillarum infection. For heavy metals exposure, the expression level of VpFer1 was significantly induced by Cd at 48 h, but kept relatively constant after exposure to Cu. With regards to VpFer2, the expression level dropped significantly at 24 h, then began to increase to the peak value at 48 h under Cd exposure, while Cu exposure constantly depressed the expression level of VpFer2 throughout the time course. Similarly, VpFer2 seemed to be more sensitive to heavy metals exposure than VpFer1 as its mRNA level changed by higher magnitudes. All these results suggested that VpFers may be important proteins involved in host immune defense and heavy metals detoxification. The diverse expression patterns of VpFers demonstrated that VpFer2 was an early and sensitive responder to environmental stress in V. philippinarum.

Proteome mapping of adult zebrafish marrow neutrophils reveals partial cross species conservation to human peripheral neutrophils

Neutrophil granulocytes are pivotal cells within the first line of host defense of the innate immune system. In this study, we have used a gel-based LC-MS/MS approach to explore the proteome of primary marrow neutrophils from adult zebrafish. The identified proteins originated from all major cellular compartments. Gene ontology analysis revealed significant association of proteins with different immune-related network and pathway maps. 75% of proteins identified in neutrophils were identified in neutrophils only when compared to neutrophil-free brain tissue. Moreover, cross-species comparison with human peripheral blood neutrophils showed partial conservation of immune-related proteins between human and zebrafish. This study provides the first zebrafish neutrophil proteome and may serve as a valuable resource for an understanding of neutrophil biology and innate immunity.