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Introduction Recent evidence suggests that ferroportin (FPN) Q248H may confer a survival advantage against malaria by reducing erythrocytic intracellular iron in Africans. We investigated if FPN Q248H mutation, that is prevalent in Batswana, is a factor in limiting the susceptibility to Plasmodium falciparum malaria. Methods 264 archived dried blood spot samples (183 P. falciparum malaria cases and 81 controls, matched for geographical region and season for equal exposure) were genotyped. Human and P. falciparum DNA was extracted using Chelex-100 resin and P. falciparum molecular confirmation performed. Ferroportin Q248H mutation was identified by restriction fragment length polymorphism. The prevalence of the FPN Q248H mutation and allele frequency and the accompanying 95% confidence interval were calculated. A qPCR method was employed to estimate P. falciparum parasitaemia. Association between FPN and malaria susceptibility was tested using Pearson Chi-square test and Mood's median test was used to compare P. falciparum parasitaemias according to FPN Q248H mutation. Results All samples were successfully genotyped. The FPN Q248H allele frequency was 0.08 (95% CI: 0.05–0.11) in cases and 0.08 (95% CI: 0.02–0.14) in controls, consistent with Hardy-Weinberg equilibrium. The prevalence of FPN Q248H phenotype was comparable in patients with P. falciparum malaria and in un-infected individuals, 16.4% (95% CI: 11.0–21.8) vs 14.8% (95% CI: 7.1–22.5), P = 0.746. In addition, no association of presence of FPN Q248H with reduced parasitaemia was recorded, P = 0.837. Conclusion In this small study, FPN Q248H polymorphism prevalence was comparable between patients with P. falciparum malaria and control subjects in the low-endemic setting of Botswana.

BACKGROUND: The ferroxidase zyklopen (Zp) has been implicated in the placental transfer of iron to the fetus. However, the evidence for this is largely circumstantial. OBJECTIVES: This study aimed to determine whether Zp is essential for placental iron transfer. METHODS: A model was established using 8- to 12-wk-old pregnant C57BL/6 mice on standard rodent chow in which Zp was knocked out in the fetus and fetal components of the placenta. Zp was also disrupted in the entire placenta using global Zp knockout mice. Inductively coupled plasma MS was used to measure total fetal iron, an indicator of the amount of iron transferred by the placenta to the fetus, at embryonic day 18.5 of gestation. Iron transporter expression in the placenta was measured by Western blotting, and the expression of Hamp1, the gene encoding the iron regulatory hormone hepcidin, was determined in fetal liver by real-time PCR. RESULTS: There was no change in the amount of iron transferred to the fetus when Zp was disrupted in either the fetal component of the placenta or the entire placenta. No compensatory changes in the expression of the iron transport proteins transferrin receptor 1 or ferroportin were observed, nor was there any change in fetal liver Hamp1 mRNA. Hephl1, the gene encoding Zp, was expressed mainly in the maternal decidua of the placenta and not in the nutrient-transporting syncytiotrophoblast. Disruption of Zp in the whole placenta resulted in a 26% increase in placental size (P

The control over iron availability is crucial under homeostatic conditions and even more in the case of an infection. This results from diverse properties of iron: first, iron is an important trace element for the host as well as for the pathogen for various cellular and metabolic processes, second, free iron catalyzes Fenton reaction and is therefore producing reactive oxygen species as a part of the host defense machinery, third, iron exhibits important effects on immune cell function and differentiation and fourth almost every immune activation in turn impacts on iron metabolism and spatio-temporal iron distribution. The central importance of iron in the host and microbe interplay and thus for the course of infections led to diverse strategies to restrict iron for invading pathogens. In this review, we focus on how iron restriction to the pathogen is a powerful innate immune defense mechanism of the host called "nutritional immunity". Important proteins in the iron-host-pathogen interplay will be discussed as well as the influence of iron on the efficacy of innate and adaptive immunity. Recently described processes like ferritinophagy and ferroptosis are further covered in respect to their impact on inflammation and infection control and how they impact on our understanding of the interaction of host and pathogen.

A full-term pregnancy comes with significant demand for iron. Not meeting this demand has adverse effects on maternal health and on the intrauterine and postnatal development of the infant. In the infant, some of these adverse effects cannot be reversed by postnatal iron supplementation, highlighting the need to tackle iron deficiency in utero. Achieving this requires sound understanding of the pathways that govern iron transfer at the fetomaternal interface. Two pathways are emerging as key players in this context; the hepcidin/ferroportin axis pathway and the iron regulatory protein (IRPs) pathway. In late gestation, suppression of maternal hepcidin, by as yet unknown factors, is required for increasing iron availability to the growing fetus. In the placenta, the rate of iron uptake by transferrin receptor TfR1 at the apical/maternal side and of iron release by ferroportin FPN at the basal/fetal side is controlled by IRP1. In fetal hepatocytes, build up of fetal iron stores requires post-translational inhibition of FPN by the cell-autonomous action of hepcidin. In the fetal liver, FPN is also subject to additional control at the transcriptional level, possibly by the action of hypoxia-inducible factor HIF2α. The rates of apical iron uptake and basal iron release in the placenta are modulated according to iron availability in the maternal blood and the placenta's own needs. This placental modulation ensures that the amount of iron delivered to the fetal circulation is maintained within a normal range, even in the face of mild maternal iron deficiency or overload. However, when maternal iron deficiency or overload are extreme, placental modulation is not sufficient to maintain normal iron supply to the fetus, resulting in fetal iron deficiency and overload respectively. Thus, the rate of iron transfer at the fetomaternal interface is subject to several regulatory signals operating simultaneously in the maternal liver, the placenta and the fetal liver. These regulatory signals act in concert to maintain normal iron supply to the fetus within a wide range of maternal iron states, but fail to do so when maternal iron deficiency or overload are extreme. The limitations of existing experimental models must be overcome if we are to gain better understanding of the role of these regulatory signals in normal and complicated pregnancy. Ultimately, that understanding could help identify better markers of fetal iron demand and underpin novel iron replacement strategies to treat maternal and fetal iron deficiency.

In this study, we evaluated the anti-tumor effects of dioscin, a steroidal saponin, on melanoma cells. Dioscin significantly inhibited cell viability and induced cell death of melanoma cells in a time- and dose- dependent manner. Furthermore, dioscin increased the concentration of intracellular ferrous irons, MDA and ROS. This effect could be inhibited by L-g-glutamyl-p-nitroanilide (GPNA), compound 968 and ferroptosis inhibitor ferrostatin-1 (Fer-1). Furthermore, dioscin induced ferroptosis by affecting the expression of transferrin and ferroportin which are regulators of intracellular levels of iron. Finally, dioscin in combination with various chemotherapeutic agents showed synergistic effects against melanoma cells. Our data suggested that dioscin exerted anti-tumor effects in melanoma cells by inducing ferroptosis. Dioscin alone or with other agents might be applied as a promising strategy to treat melanoma.

Age-related cataracts (ARC) are the primary cause of blindness worldwide, and oxidative stress is considered the central pathogenesis of age-related cataractogenesis. Interestingly, ample evidence suggests that there is no remarkable apoptosis present in aged and cataractous human lenses despite the profound disruption of redox homeostasis, raising an essential question regarding the existence of other cell death mechanisms. Here we sought to explore the lens epithelial cell's (LEC) susceptibility to ferroptosis after documentation has concluded that aged and cataractous human lenses manifest with increased reactive oxygen species (ROS) formation, elevated lipid peroxidation, and accumulative intracellular redox-active iron, constituting the three hallmarks of ferroptosis during aging and cataractogenesis. Here we show that very low concentrations of system Xc- inhibitor Erastin (0.5 μM) and glutathione peroxidase 4 (GPX4) inhibitor RSL3 (0.1 μM) can drastically induce human LEC (FHL124) ferroptosis in vitro and mouse lens epithelium ferroptosis ex vivo. Depletion of intracellular glutathione (GSH) in human LECs and mouse lens epithelium significantly sensitizes ferroptosis, particularly under RSL3 challenge. Intriguingly, both human LECs and the mouse lens epithelium demonstrate an age-related sensitization of ferroptosis. Transcriptome analysis indicates that clusters of genes are up-or down-regulated in aged LECs, impacting cellular redox and iron homeostases, such as downregulation of both cystine/glutamate antiporter subunits SLC7A11 and SLC3A2 and iron exporter ferroportin (SLC40A1). Here, for the first time, we are suggesting that LECs are highly susceptible to ferroptosis. Moreover, aged and cataractous human lenses may possess more pro-ferroptotic criteria than any other organ in the human body.

Objective: Cognitive dysfunction often accompanies diabetes. Both hypoglycemia and hyperglycemia cause cognitive dysfunctions. However, the underlying pathophysiology remains unclear. Recent evidence show that ferroptosis primarily triggers nerve cell death, Alzheimer's disease (AD), Huntington’s disease (HD), and Parkinson's disease (PD). We purposed to investigate whether ferroptosis is a vital pathogenic pathway in diabetes-induced cognitive dysfunction. Methods and results: Type 1 diabetic rat model was created by intraperitoneal injection of streptozotocin (STZ). Significant cognitive dysfunction was observed in the diabetic rats as evidenced by increase in latency period to find a hidden platform and decreased cumulative time spent in the target quadrant in the Morris water maze test. We detected the amplitude of low-frequency fluctuation (ALFF) of the BOLD (Blood Oxygenation Level-Dependent) signal using resting-state functional magnetic resonance imaging (rs-fMRI). Consequently, we found that the ALFF values, as well as the T2 relaxation time of the bilateral hippocampus, were reduced in Type 1 diabetic rats. We detected Fe2+ level and lipid peroxidation products (MDA and 4-HNE) in the hippocampus. Mitochondria and neuron injury in the STZ-induced diabetic rats were determined using a Transmission Electron Microscope and Nissl body staining. Iron overload and ferroptosis were detected in the hippocampus. Furthermore, mRNA microarray analysis revealed 201 dysregulated mRNAs in STZ-induced type 1 diabetes (T1D). Pathway enrichment analyses indicated that differentially expressed mRNAs associated-coding genes were associated with ferroptosis. Among ferroptosis signaling pathway genes, Slc40a1 gene (ferroportin) was downregulated.Conclusion: We show that ferroptosis is associated with diabetic cognitive dysfunction and Slc40a1 mediates ferroptosis in Type 1 diabetes.

Anemia is common in patients with chronic kidney disease (CKD) and results from the dysregulation of iron metabolism and erythropoiesis. Hepcidin is a key regulator of iron availability and leads to iron sequestration during the state of iron repletion. Decreases in the level of hepcidin in the presence of hypoxia and/or iron limitation allow for greater iron availability for erythropoiesis. However, kidney excretion of hepcidin decreases as the severity of CKD increases, whereas production of hepcidin is increased under inflammatory conditions often present in patients with CKD, both of which contribute to anemia. Assessment of iron status is, therefore, essential in the treatment of anemia. However, current laboratory tests for the determination of the adequate supply of iron have many limitations, including diurnal variation in the levels of biomarkers, lack of standardized reference methods across laboratories, and confounding by the presence of inflammation. In addition, the current treatment paradigm for anemia of CKD can further disrupt iron homeostasis; for example, treatment with erythropoiesis-stimulating agents in the absence of supplemental iron can induce functional iron deficiency. Moreover, supplemental iron can further increase levels of hepcidin. Several novel therapies, including hypoxia-inducible factor prolyl hydroxylase inhibitors and hepcidin inhibitors/antagonists, have shown promise in attenuating the levels and/or activity of hepcidin in anemia of CKD, thus ensuring the availability of iron for erythropoiesis.

Anaemia of chronic disease (ACD) is generated by the activation of the immune system by autoantigens, microbial molecules or tumour antigens resulting in the release of cytokines that cause an elevation of serum hepcidin, hypoferraemia, suppression of erythropoiesis, decrease in erythropoietin (EPO) and shortening of the half-life of red blood cells. Anaemia is usually normocytic and normochromic, which is the most prevalent after iron deficiency anaemia, and it is the most frequent in the elderly and in hospitalized patients. If the anaemia is severe, the patient's quality of life deteriorates, and it can have a negative impact on survival. Treatment is aimed at controlling the underlying disease and correcting anaemia. Sometimes intravenous iron and EPO have been used, but the therapeutic future is directed against hepcidin, which is the final target of anaemia.

Hepcidin links iron metabolism with innate immunity during the inhibition of bacterial infection. Our previous studies had shown that recombinant hepcidin can significantly reduce the mortality rate of Ctenopharyngodon idella infected with Flavobacterium columnare under laboratory conditions. Here, we studied the preventive and therapeutic effects of feed supplemented with different doses of recombinant hepcidin on F. columnare-challenged C. idella reared in a cage culture environment. The results showed that in the prevention groups, 30 and 90 mg/kg of added purified and unpurified hepcidin respectively resulted in a higher survival rate in the early post-infection period, while 60 mg/kg of purified hepcidin significantly improved the survival rate in the therapy group (all compared to the control group). In the hepatopancreas, the expression of hepcidin and ferritin was significantly up-regulated, and the levels of ferroportin and serum iron were significantly decreased, especially in the therapy group. In addition, the expression of iron-related genes in spleen and intestine exhibited a similar trend to that in hepatopancreas. Meanwhile, immune genes were up-regulated to varying degrees, and the therapy group exhibited a significantly improved expression of pro-inflammatory cytokines and specific immunity. In summary, our study shows that different doses of recombinant hepcidin had protective effects against bacterial infection by regulating the iron distribution and immune gene expression, which provides a strong foundation for the application of recombinant hepcidin in aquaculture.

Background Hepcidin is a key regulator of iron homeostasis. Some studies showed that exogenous hepcidin decreased the expression of divalent metal transporter (DMT1) rather than ferroportin(FPN1) to regulate renal iron metabolism. This study explored the effects of hepcidin synthesized by the kidney and its mechanism of iron regulation. Methods In the in vivo experiments, mice were divided into a unilateral ureter obstruction (UUO) model group and a sham operation group, and mice in the UUO model group were sacrificed on days 1, 3, 5 and 7. The expression of renal hepcidin, FPN1, DMT1 and the retention of renal iron were studied. In the in vitro experiments, we overexpressed hepcidin in HK-2 cells. Then we tested the expression of renal hepcidin, FPN1, DMT1 and observed the production of intracellular ferrous ions. Results Renal hepcidin expression was consistently higher in the UUO group than in the sham group from the first day. The expression of FPN1 gradually decreased, and the expression of DMT1 gradually increased in the UUO model. Intracellular ferrous ions significantly increased on the first day of the UUO model. In hepcidin overexpressed HK-2 cells, the expression of FPN1 was decreased, while the expression of DMT1 has no significant change. In addition, production of intracellular ferrous ions increased. Conclusion: local hepcidin can regulate iron metabolism in the kidney by adjusting the expression of FPN1.

Iron overload causes osteoporosis by enhancing osteoclastic bone resorption. During differentiation, osteoclasts demand high energy and contain abundant mitochondria. In mitochondria, iron is used for the synthesis of Fe-S clusters to support mitochondria biogenesis and electron transport chain. Moreover, mitochondrial reactive oxygen species (ROS) play an important role in osteoclastogenesis. Activation of MAPKs (ERK1/2, JNK, and p38) by ROS is essential and contribute to osteoclast differentiation. How iron chelation impairs electron transport chain and ROS dependent MAPKs activation during osteoclast differentiation is unknown. This study aimed to determine the direct effects of iron chelation on osteoclast differentiation, electron transport chain and MAPKs activation. In the present study, we found that when iron chelator, deferoxamine (DFO), was added, a dose-dependent inhibition of osteoclast differentiation and bone resorption was observed. Supplementation of transferrin-bound iron recovered osteoclastogenesis. Iron chelation resulted in a marked decrease in ferritin level, and increased expression of transferrin receptor 1 and ferroportin. As an iron chelator, DFO negatively affected mitochondrial function through decreasing activities of all the complexes. Expressions of mitochondrial subunits encoded both by mitochondrial and nuclear DNA were decreased. DFO augmented production of mitochondrial ROS, but inhibited the phosphorylation of ERK1/2, JNK, and p38, even in the presence of hydrogen peroxide. These results suggest that iron chelation directly inhibits iron-uptake stimulated osteoclast differentiation and suppresses electron transport chain. Iron chelation negatively regulates MAPKs activation, and this negative regulation is independent on ROS stimulation.

Iron metabolism is altered in a variety of cancers; however, little is known about the role of iron metabolism in the biology and response to therapy of acute myeloid leukemia (AML). Here we show that SLC40A1, the gene encoding the iron exporter ferroportin (FPN), is variably expressed among primary AMLs and that low levels are associated with good prognosis and improved outcomes. In particular, core binding factor (CBF) AMLs, which are associated with good outcomes with chemotherapy, consistently have low level of SLC40A1 expression. AML cell lines that expressed relatively low levels of FPN endogenously, or were engineered via gene knockdown, had an increased sensitivity to chemotherapy relative to controls expressing high levels of FPN. Primary FPNlow AML bulk cells also had increased sensitivity to Ara-C treatment, iron treatment and the combination of Ara-C and iron relative to FPNhigh cells. FPNlow leukemic stem cells (LSCs) had decreased viability following addition of iron alone and in combination with Ara-C treatment relative to FPNhigh LSCs. Together these observations suggest a model where FPN mediated iron metabolism may play a role in chemosensitivity and outcome to therapy in AML.

Zinc oxide nanoparticles (ZnO NPs) are one of the most widely used nanomaterials. Following oral exposure, these NPs can accumulate in various organs and induce the toxicity due to their physiochemical characteristics. In present study to reduce the toxicity, surface engineered ZnO NPs (c-ZnO NPs) were in-situ synthesized by using polyacrylamide grafted guar gum (PAm-g-GG) polymer in alkaline media. Further, the comparative effect of bared ZnO NPs (b-ZnO NPs) and c-ZnO NPs were assessed on secondary target organ liver and kidneys of Swiss mice at doses of 10, 50 and 300 mg/kg following 28 days repeated oral treatment. The b-ZnO NPs were incited severe damages in liver and kidney tissue than c-ZnO NPs as seen by transmission electron microscopy and histopathology. The increased levels of serum biomarkers (AST, ALT, ALP, creatinine, uric acid, and urea) were also observed, that remarking a disturbance in the function of liver and kidney. After sub-acute oral treatment of b-ZnO NPs, the hepatic pro-inflammatory cytokines (IL-6, TNF-α, and MMP-9) were up-regulated that causes the activation of acute phase response (APR). We also observed significantly increased in expression of hepatic acute phase proteins (hepcidin and haptoglobin) and altered interlinked iron (Fe) signaling biomarkers (hephaestin, TF, TFR-1, LDH, and ferroportin). This study emphasizes that exposure to ZnO NPs may cause inflammation mediated APR through ultra-structural damage of tissue that could escort the progression of anemia. Nevertheless, the capping with PAm-g-GG in c- ZnO NPs has reduced the toxicity by altering the surface reactive property of ZnO NPs.

BACKGROUND Iron oversupplementation in healthy term infants may adversely affect growth and cognitive development. OBJECTIVE We hypothesized that early-life iron excess causes systemic and central nervous system iron overload, and compromises social behavior. METHODS The nursing pig was used as a translational model in a completely randomized study. On postnatal day (PD) 1, 24 pigs (1.57 ± 0.28 kg mean ± standard deviation body wt) were assigned to the following treatment groups: 1) nonsupplemented iron-deficient group (NON); 2) control group (CON), intramuscularly injected with iron dextran (100 mg Fe) on PD2; 3) moderate iron group (MOD), orally administered ferrous sulfate at 10 mg Fe · kg body wt-1 · d-1; and 4) high iron group (HIG), orally administered ferrous sulfate at 50 mg Fe · kg-1 · d-1. Piglets were nursed by sows during the study from PD1 to PD21. Tissue iron was analyzed by atomic absorption spectrophotometry. Messenger RNA and protein expression of iron regulator and transporters were analyzed by quantitative reverse transcriptase-polymerase chain reaction and Western blot. A sociability test was performed on PD19-20. RESULTS Both MOD and HIG treatments (5.51 and 9.85 µmol/g tissue), but not CON (0.54 µmol/g), increased hepatic iron as compared with NON (0.25 µmol/g, P

The bone morphogenetic protein (BMP) type I receptors ALK2 and ALK3 are essential for expression of hepcidin, a key iron regulatory hormone. In mice, hepatocyte-specific Alk2 deficiency leads to moderate iron overload with periportal liver iron accumulation, while hepatocyte-specific Alk3 deficiency leads to severe iron overload with centrilobular liver iron accumulation and a more marked reduction of basal hepcidin levels. The objective of this study was to investigate whether the two receptors have additive roles in hepcidin regulation. Iron overload in mice with hepatocyte-specific Alk2 and Alk3 (Alk2/3) deficiency was characterized and compared to hepatocyte-specific Alk3 deficient mice. Co-immunoprecipitation studies were performed to detect the formation of ALK2 and ALK3 homodimer and heterodimer complexes in vitro in the presence and absence of ligands. The iron overload phenotype of hepatocyte-specific Alk2/3-deficient mice was more severe than that of hepatocyte-specific Alk3-deficient mice. In vitro co-immunoprecipitation studies in Huh7 cells showed that ALK3 can homodimerize in absence of BMP2 or BMP6. In contrast, ALK2 did not homodimerize in either the presence or absence of BMP ligands. However, ALK2 did form heterodimers with ALK3 in the presence of BMP2 or BMP6. ALK3-ALK3 and ALK2-ALK3 receptor complexes induced hepcidin expression in Huh7 cells. Our data indicate that: (I) ALK2 and ALK3 have additive functions in vivo, as Alk2/3 deficiency leads to a greater degree of iron overload than Alk3 deficiency; (II) ALK3, but not ALK2, undergoes ligand-independent homodimerization; (III) the formation of ALK2-ALK3 heterodimers is ligand-dependent and (IV) both receptor complexes functionally induce hepcidin expression in vitro.

Resetting M2-like tumor-associated macrophages (TAMs) to antitumor M1 phenotype is a promising strategy in cancer immunotherapy. Although iron-based nanoparticles exhibit the potential of M2-to-M1 macrophage repolarization, the efficient M2-like TAM targeting and the subsequent intracellular iron retention remains a big challenge. Here, M2 macrophage-targeting peptide-conjugated iron-based metal-organic frameworks are developed to load diclofenac (Dic@M2pep-Fe-MOF) for enhanced cancer immunotherapy. Dic@M2pep-Fe-MOF efficiently targets M2-like TAMs and decreases the efflux by hepcidin/ferroportin signaling pathway, enabling enhanced intracellular accumulation for improved M2-to-M1 macrophage repolarization. Dic@M2pep-Fe-MOF-repolarized M2-like TAMs efficiently kill and phagocytose tumor cells, and importantly remodel tumor immune microenvironment to generate long-term antitumor immune memory, eliciting strong anticancer efficacy with tumor recurrence inhibition. Our results support Dic@M2pep-Fe-MOF as a potential drug for cancer immunotherapy.

Iron is an essential trace element required for several vital physiological and developmental processes, including erythropoiesis, bone, and neuronal development. Iron metabolism and oxygen homeostasis are interlinked to perform a vital role in the functionality of the heart. The metabolic machinery of the heart utilizes almost 90 % of oxygen through the electron transport chain. To handle this tremendous level of oxygen, the iron metabolism in the heart is utmost crucial. Iron availability to the heart is therefore tightly regulated by (i) the hepcidin/ferroportin axis, which controls dietary iron absorption, storage, and recycling, and (ii) iron regulatory proteins 1 and 2 (IRP1/2) via hypoxia inducible factor 1 (HIF1) pathway. Despite iron being vital to the heart, recent investigations have demonstrated that iron imbalance is a common manifestation in conditions of heart failure (HF), since free iron readily transforms between Fe2+ and Fe3+via the Fenton reaction, leading to reactive oxygen species (ROS) production and oxidative damage. Therefore, to combat iron-mediated oxidative stress, targeting Nrf2/ARE antioxidant signaling is rational. The involvement of Nrf2 in regulating several genes engaged in heme synthesis, iron storage, and iron export is beginning to be uncovered. Consequently, it is possible that Nrf2/hepcidin/ferroportin might act as an epicenter connecting iron metabolism to redox alterations. However, the mechanism bridging the two remains obscure. In this review, we tried to summarize the contemporary insight of how cardiomyocytes regulate intracellular iron levels and discussed the mechanisms linking cardiac dysfunction with iron imbalance. Further, we emphasized the impact of Nrf2 on the interplay between systemic/cardiac iron control in the context of heart disease, particularly in myocardial ischemia and HF.

Fluorescence microscopy, as a sensitive method to detect microenvironment of molecules, is widely used in protein conformation and dynamic studies in live cells. Fluorescence lifetime imaging microscopy (FLIM), which is independent of fluorophore concentrations, scattering and bleaching, is a suitable tool to analyze membrane proteins in a single cell. Ferroportin (FPN), a multi-ion exporter in vertebrates, was modulated by metal ions with unknown mechanism. Herein, we fused green fluorescence protein on C-terminal of FPN (FPN-eGFP) and applied fluorescence lifetime to monitor conformation changes of FPN in a live cell. The fluorescence lifetime distribution showed a shift to shorter lifetime upon Mn2+ treatment, suggesting a preference conformation of FPN in Mn2+ exposure. It is also observed that the lifetime (rather than intensity) measurement was not strongly influenced by laser power. The observed fluorescence lifetime changes of FPN-eGFP upon Mn2+ treatments indicated that extracellular metal ions can modulate FPN through conformation exchanges between several different states.

Iron is an essential biometal in the aqueous humor, the principal source of nutrients for the avascular cornea and the lens. Here, we explored whether the ciliary body (CB), the source of aqueous humor, transports iron, and if the prion protein (PrPC) facilitates this process as in the outer retina. Using a combination of human, bovine, and mouse eyes as models, we report the expression of iron export proteins ferroportin and ceruloplasmin, and major iron uptake and storage proteins transferrin, transferrin receptor, and ferritin in the ciliary epithelium, indicating active exchange of iron at this site. Ferroportin and transferrin receptor are also expressed in the corneal endothelium. However, the relative expression of iron export and uptake proteins suggests export from the ciliary epithelium and import by corneal endothelium. In addition, abundant expression of PrPC, a ferrireductase that facilitates iron transport, is noted in pigmented and non-pigmented epithelium of the CB, posterior pigmented epithelium of the iris, corneal endothelium and epithelium, and lens epithelium. Notably, majority of PrPC in the ciliary epithelium is cleaved at the β-site as in retinal pigment epithelial cells, suggesting a role in iron transport. Most of the PrPC in the cornea, however, is full-length, and susceptible to aggregation by intracerebrally inoculated PrP-scrapie, an infectious conformation of PrPC responsible for human and animal prion disorders. Soluble PrPC is present in the aqueous and vitreous humor, a provocative observation with significant implications. Together, these observations suggest independent cycling of iron in the anterior segment, and a prominent role of PrPC in this process. Aggregation of PrPC in the cornea of PrP-scrapie-infected animals raises the alarming possibility of transmission of animal prions through corneal abrasions.

Cadmium (Cd) has been linked to a variety of cancers, including breast cancer; however, the molecular mechanism of its carcinogenic activity is not fully understood. To this end, the present study investigated the roles of ferroportin (FPN), a prognostic marker of breast cancer, in Cd-induced stimulation of cell proliferation and cell migration. Triple-negative MDA-MB-231 cells were treated with 1–3 μM Cd. The cells exhibited significant reduction in FPN expression and concomitant increase in iron concentration. Cells treated with Cd for 8 weeks displayed elevated proliferative and migratory activities which were inversely related with FPN expression. Reduced FPN expression also resulted in EMT as indicated by an increase in the expression of E-cadherin, and a decrease in the expression of N-cadherin, Twist and Slug. Further investigation revealed that Cd suppressed FPN expression at least partially by activating TGF-β, a known regulator of FPN expression. Taken together, these results indicate that Cd-induced stimulation of MDA-MB-231 cell proliferation, EMT, and migration is brought about by suppression of FPN expression and associated disruption of iron homeostasis.

Aging has been associated with iron retention in many cell types, including the neurons, promoting neurodegeneration by ferroptosis. Excess intracellular iron accelerates aging by damaging the DNA and blocking genomic repair systems, a process we define as ferrosenescence. Novel neuroimaging and proteomic techniques have pinpointed indicators of both iron retention and ferrosenescence, allowing for their early correction, potentially bringing prevention of neurodegenerative disorders within reach. In this review, we take a closer look at the early markers of iron dyshomeostasis in neurodegenerative disorders, focusing on preventive strategies based on nutritional and microbiome manipulations.

In order to discover new drug delivery approaches and to understand the mechanism of iron overload in cerebral ischemia/reperfusion (I/R), we aimed to investigate the effects of lycopene (LYC) in the form of nano-liposomes (L-LYC) on iron-regulating proteins and ischemic brain injury. We found that L-LYC significantly increased the LYC content in serum and the brain. Adult male Sprague-Dawley rats treated with L-LYC for 14 days were subjected to 60 min of ischemia and 7 days of reperfusion. The effects of L-LYC were evaluated by infarction volume, neurological score, neuronal apoptosis, and markers for oxidative stress. Levels of iron-regulating protein such as hepcidin and ferroportin (FPN1) were examined. L-LYC reduced cerebral infarction and improved neurobehavior of the rats more efficiently than “naked” LYC. L-LYC reduced protein levels of oxidases (e.g. nitric oxide synthase and NOX2), increased the level of Bcl-2, lowered caspase-3, and suppressed apoptosis through inhibiting MAPK-JNK. Furthermore, L-LYC suppressed hepcidin-mediated decrease in FPN1, a sole iron exporter, and normalized the levels of iron. We further demonstrated that the effect of L-LYC on hepcidin expression might result from its ability to attenuate the release of the inflammatory factor interleukin 6. The results demonstrated that nano-liposomal encapsulation significantly improved LYC efficacy in providing neuronal protection against I/R injury. The data also revealed a novel mechanism of L-LYC's neuroprotection by regulating iron metabolism in an ischemic brain.

Multicopper oxidases (MCOs) are a specific group of enzymes that contain multiple copper centers through which different substrates are oxidized. Main members of MCO family include ferroxidases, ascorbate oxidases, and laccases. MCO type of ferroxidases is key to iron transport across the plasma membrane. In Drosophila, there are four potential multicopper oxidases, MCO1-4. No convincing evidence has been presented so far to indicate any of these, or even any insect multicopper oxidase, to be a ferroxidase. Here we show Drosophila MCO3 (dMCO3) is highly likely a bona fide ferroxidase. In vitro activity assay with insect-cell-expressed dMCO3 demonstrated it has potent ferroxidase activity. Meanwhile, the ascorbate oxidase and laccase activities of dMCO3 are much less significant. dMCO3 expression in vivo, albeit at low levels, appears mostly extracellular, reminiscent of mammalian ceruloplasmin in the serum. A null dMCO3 mutant, generated by CRISPR/Cas9 technology, showed disrupted iron homeostasis, evidenced by increased iron level and reduced metal importer Mvl expression. Notably, dMCO3-null flies phenotypically are largely normal at normal or iron stressed-conditions. We speculate the likely existence of a similar iron efflux apparatus as the mammalian ferroportin/ferroxidase in Drosophila. However, its importance to fly iron homeostasis is greatly minimized, which is instead dominated by another iron efflux avenue mediated by the ZIP13-ferritin axis along the ER/Golgi secretion pathway.

The acute-phase response is triggered by the presence of infectious agents and danger signals which indicate hazards for the integrity of the mammalian body. One central feature of this response is the sequestration of iron into storage compartments including macrophages. This limits the availability of this essential nutrient for circulating pathogens, a host defence strategy known as 'nutritional immunity'. Iron metabolism and the immune response are intimately linked. In infections, the availability of iron affects both the efficacy of antimicrobial immune pathways and pathogen proliferation. However, host strategies to withhold iron from microbes vary according to the localization of pathogens: Infections with extracellular bacteria such as Staphylococcus aureus, Streptococcus, Klebsiella or Yersinia stimulate the expression of the iron-regulatory hormone hepcidin which targets the cellular iron-exporter ferroportin-1 causing its internalization and blockade of iron egress from absorptive enterocytes in the duodenum and iron-recycling macrophages. This mechanism disrupts both routes of iron delivery to the circulation, contributes to iron sequestration in the mononuclear phagocyte system and mediates the hypoferraemia of the acute phase response subsequently resulting in the development of anaemia of inflammation. When intracellular microbes are present, other strategies of microbial iron withdrawal are needed. For instance, in macrophages harbouring intracellular pathogens such as Chlamydia, Mycobacterium tuberculosis, Listeria monocytogenes or Salmonella Typhimurium, ferroportin-1-mediated iron export is turned on for the removal of iron from infected cells. This also leads to reduced iron availability for intra-macrophage pathogens which inhibits their growth and in parallel strengthens anti-microbial effector pathways of macrophages including the formation of inducible nitric oxide synthase and tumour necrosis factor. Iron plays a key role in infectious diseases both as modulator of the innate immune response and as nutrient for microbes. We need to gain a more comprehensive understanding of how the body can differentially respond to infection by extra- or intracellular pathogens. This knowledge may allow us to modulate mammalian iron homeostasis pharmaceutically and to target iron-acquisition systems of pathogens, thus enabling us to treat infections with novel strategies that act independent of established antimicrobials.

Osteoporosis, osteopenia, and pathological bone fractures are frequent complications of iron-overload conditions such as hereditary hemochromatosis, thalassemia, and sickle cell disease. Moreover, animal models of iron overload have revealed increased bone resorption and decreased bone formation. Although systemic iron overload affects multiple organs and tissues, leading to significant changes on bone modeling and remodeling, the cell autonomous effects of excessive iron on bone cells remain unknown. Here, to elucidate the role of cellular iron homeostasis in osteoclasts, we generated two mouse strains in which solute carrier family 40 member 1 (Slc40a1), a gene encoding ferroportin (FPN), the sole iron exporter in mammalian cells, was specifically deleted in myeloid osteoclast precursors or mature cells. The FPN deletion mildly increased iron levels in both precursor and mature osteoclasts, and its loss in precursors, but not in mature cells, increased osteoclastogenesis and decreased bone mass in vivo. Of note, these phenotypes were more pronounced in female than in male mice. In vitro studies revealed that the elevated intracellular iron promoted macrophage proliferation and amplified expression of nuclear factor of activated T cells 1 (Nfatc1) and PPARG coactivator 1β (Pgc-1β), two transcription factors critical for osteoclast differentiation. However, the iron excess did not affect osteoclast survival. While increased iron stimulated global mitochondrial metabolism in osteoclast precursors, it had little influence on mitochondrial mass and reactive oxygen species production. These results indicate that FPN-regulated intracellular iron levels are critical for mitochondrial metabolism, osteoclastogenesis, and skeletal homeostasis in mice.

We previously reported that the bone morphogenetic protein (BMP) antagonist, noggin, improved the repair process with an increase in the reactive microglia/macrophage population in the ischemic brain. Since BMP plays a role in intracellular iron homeostasis via the hepcidin/ferroportin axis, and iron is required for myelination, this study was aimed to determine whether noggin affected iron status and remyelination in the brain following ischemic stroke. We further examined the effect of blocking the BMP/hepcidin pathway on reactive microglia (BV2) and myelination of oligodendroglial cells (MO3.13) to define the link between microglial iron status and myelin formation. Following the noggin infusion into the ischemic brain of mice, the induction of hepcidin and ferritin protein levels decreased, and the number of myelinated axons and myelin thickness increased at 8 weeks after ischemic stroke. Noggin repressed the increase in hepcidin and ferritin levels in BV2 exposed to lipopolysaccharide (LPS) and oxygen/glucose deprivation and reperfusion (OGD/R). When MO3.13 were exposed to the conditioned media from noggin-treated BV2 (noggin CM) during reperfusion, OGD/R-induced MO3.13 cell death was reduced. Under normal conditions, noggin CM induced myelin production with an increase in ferritin levels in MO3.13, which was reversed by the iron chelator, deferoxamine. These results indicated that noggin altered the iron status in reactive microglia from the iron-storing to the iron-releasing phenotype, which contributed to myelin synthesis by providing iron. We suggest that the BMP/hepcidin pathway can be a target for the regulation of the iron status in microglia to enhance remyelination in the ischemic brain.

Sepsis is a known risk factor for new-onset atrial fibrillation (AF), and previous studies have demonstrated that ferroptosis participates in sepsis-induced organ injury development. Nevertheless, the role of ferroptosis in new-onset AF with sepsis remains largely unknown. This study aims to investigate the underlying mechanisms linking ferroptosis and AF caused by sepsis. LPS-induced endotoxemia is often used to model the acute inflammatory response associated with sepsis. Herein, we reported that ferroptosis was significantly activated in LPS-induced endotoxemia rat model. We also observed that ferroportin (Fpn), the only identified mammalian non-heme iron exporter, was downregulated in the atrium of endotoxemia model. Vulnerability to AF was also significantly increased in a endotoxemia rat model. Additionally, Fpn knockdown by shFpn further increased intracellular iron concentration and oxidative stress and exaggerated the AF vulnerability, which was alleviated by ferroptosis inhibition. Mechanistically, silencing Fpn worsened the alterations in calcium handling proteins expression in a endotoxemia rat model. These findings suggest that Fpn-mediated ferroptosis is involved in the new-onset AF with LPS-induced endotoxemia via worsening the calcium handling proteins dysregulation and provides a novel and promising strategy for preventing AF development in sepsis.

Cognitive deficits are among the most common comorbidities of temporal lobe epilepsy (TLE). Ferroptosis associated with the accumulation of iron overload-dependent lipid peroxidation produces significant cognitive deficits in TLE. The anti-aging protein, klotho, has been shown to exert neuroprotective effects while enhancing cognition in neurodegenerative disorders. However, the role of klotho in TLE progression has not been established. In this study, we evaluated the effects and underlying mechanisms of klotho in a rat model of TLE induced by lithium-chloride and pilocarpine (LiCl-Pilo). The expression of klotho was found to be inhibited in the hippocampus following LiCl-Pilo induced TLE in rats. An adeno-virus (AAV), which mediated klotho overexpression (AAV-KL) was injected into the bilateral hippocampus of the rat models. After 3 weeks, rats were treated through intraperitoneal injections of LiCl-Pilo. After 9 weeks, AAV-KL was found to have significantly induced klotho overexpression in the hippocampus, effectively ameliorated cognitive deficits and exerted neuroprotective effects in LiCl-Pilo induced TLE rat models. Klotho significantly prevented ferroptosis and iron overload. Meanwhile, klotho regulated the expressions of divalent metal transporter 1 (DMT 1) and ferroportin (FPN) that were associated with iron accumulation in the hippocampus. Furthermore, klotho significantly elevated glutathione peroxidase-4 (GPX-4) and glutathione (GSH) levels while suppressed reactive oxygen species (ROS) levels. In conclusion, klotho ameliorated cognitive deficits and exerted neuroprotective effects by inhibiting ferroptosis in LiCl-Pilo induced TLE rat models.

Iron and zinc deficiencies likely coexist in general population. We have previously demonstrated that zinc treatment induces while zinc deficiency inhibits iron absorption in intestinal cell culture models, but this needs to be tested in vivo. In the present study we assessed intestinal iron absorption, iron status (haemoglobin), red blood cell number, plasma ferritin, transferrin receptor, hepcidin) and tissue iron levels in zinc depleted, replete and pair fed control rats. Zinc depletion led to reduction in body weight, tissue zinc levels, intestinal iron absorption, protein and mRNA expression of iron transporters, the divalent metal ion transporter-1, hephaestin and ferroportin, but elevated the intestinal and liver tissue iron levels compared with the pair fed control rats. Zinc repletion led to a significant weight gain compared to zinc deficient rats and normalized the iron absorption, iron transporter expression, tissue iron levels to that of pair fed control rats. Surprisingly, haemoglobin levels and red blood cell number reduced significantly in zinc repleted rats, which could be due to rapid weight gain. Together, these results indicate that whole body zinc status has profound influence on growth, intestinal absorption and systemic utilization of iron, mediated via modulation of iron transporter expression.

Divalent ions such as calcium, iron, and copper have roles in physiological functions such as maintaining ionic homeostasis. Ion channels, present in the cell membrane, control the flow of ions across the cell membrane. Hyperkalemic periodic paralysis, iron-deficiency anemia, and horse colic are related to ion channel malfunctions. Equine ion channels have not been studied as much as those in other species. In the present study, we focused on expression and localization of calcium, iron, and copper ion channels in equine duodenum, heart, kidney, liver, lung, ovary, uterus, and testis tissues. Gene and protein expressions were quantified by using real-time polymerase chain reaction and western blotting, respectively. Localization of each channel was identified via immunohistochemical analysis. Gene (mRNA) and protein levels of Nckx3 and Trpv2 were high in uterus tissue. Ferroportin (Ireg1) mRNA levels varied, but its protein level was notably high in liver. Hephaestin (Heph) mRNA level was high in duodenum, whereas its protein level was high in liver. Nckx3 was highly expressed in ovary, uterus, and testis. Trpv2 was expressed in duodenum, liver, lung, and kidney. Ferroportin was expressed in duodenum, liver, ovary, and uterus. Hephaestin was expressed in duodenum, ovary, and testis. Copper transporter 1 (Ctr1) was expressed in all tissues, whereas Atp7a was expressed in duodenum, kidney, and testis. Each protein was expressed in their respective structures, including gland, epithelium, and myocyte. Taken together, the regulation of each ion channel is important to secretion, absorption, and contraction in the various organ. The results of this study could form a basis for elucidating Nckx3-, Trpv2-, Ireg1-, Heph-, Ctr1-, and Atp7a-related diseases in horse.

Iron is an essential element for the mammalian body however, its homeostasis must be regulated accurately for appropriate physiological functioning. Alterations in physiological iron levels can lead to moderate to severe iron disorders like chronic and acute iron deficiency (anemia) or iron overload. Hepcidin plays an important role in regulating homeostasis between circulating iron and stored iron in the cells as well as the absorption of dietary iron in the intestine. Inflammatory disorders restrict iron absorption from food due to increased circulating levels of hepcidin. Increased production of hepcidin causes ubiquitination of ferroportin (FPN) leading to its degradation, thereby retaining iron in the spleen, duodenal enterocytes, macrophages, and hepatocytes. Hepcidin inhibitors and antagonists play a consequential role to ameliorate inflammation-associated anemia. Many natural and synthesized compounds, able to reduce hepcidin expression during inflammation have been identified in recent years. Few of which are currently at various phases of clinical trial. This article comprises a comprehensive review of therapeutic approaches for the efficient treatment of anemia associated with inflammation. Many strategies have been developed targeting the hepcidin-FPN axis to rectify iron disorders. Hepcidin modulation with siRNAs, antibodies, chemical compounds, and plant extracts provides new insights for developing advanced therapeutics for iron-related disorders. Hepcidin antagonist's treatment has a high potential to improve iron status in patients with iron disorders, but their clinical success needs further recognition along with the identification and application of new therapeutic approaches.

Background & aims Iron has been proposed as influencing the progression of liver disease in subjects with non-alcoholic fatty liver disease (NAFLD). We have previously shown that, in the Hfe−/− mouse model of hemochromatosis, feeding of a high-calorie diet (HCD) leads to increased liver injury. In this study we investigated whether the feeding of an iron deficient/HCD to Hfe−/− mice influenced the development of NAFLD. Methods Liver histology was assessed in Hfe−/− mice fed a standard iron-containing or iron-deficient diet plus or minus a HCD. Hepatic iron concentration, serum transferrin saturation and free fatty acid were measured. Expression of genes implicated in iron regulation and fatty liver disease was determined by quantitative real-time PCR (qRT-PCR). Results Standard iron/HCD-fed mice developed severe steatosis whereas NAS score was reduced in mice fed iron-deficient HCD. Mice fed iron-deficient HCD had lower liver weights, lower transferrin saturation and decreased ferroportin and hepcidin gene expression than HCD-fed mice. Serum non-esterified fatty acids were increased in iron-deficient HCD-fed mice compared with standard iron HCD. Expression analysis indicated that genes involved in fatty-acid binding and mTOR pathways were regulated by iron depletion. Conclusions Our results indicate that decreasing iron intake attenuates the development of steatosis resulting from a high calorie diet. These results also suggest that human studies of agents that modify iron balance in patients with NAFLD should be revisited.

Although previous studies suggested that stress erythropoiesis and iron metabolism regulate each other to increase iron availability for hemoglobin synthesis, the molecular bases determining its different traits remain elusive. In addition, global DNA demethylation has been reported during mouse erythropoiesis in vivo. However, the understanding of iron-related genes through DNA demethylation under stress erythropoiesis is largely unknown. In the current study, we found disordered iron homeostasis and misregulated hepcidin-ferroportin axis under stress erythropoiesis. Interestingly, global 5hmC content and TET2 expression were significantly induced by oxidative stress, whereas antioxidant had the opposite's effect. Mechanistic investigation manifested that TET2-mediated DNA demethylation promotes the expression of ferroportin and erythroferrone against oxidative stress. Besides, the expression of NRF2 was significantly increased by TET2-mediated DNA demethylation during stress erythropoiesis. Elevated NRF2 expression could also modulate the activation of ferroportin and erythroferrone through a canonical antioxidant response element within its promoter. These direct and indirect pathways of TET2 synergistically cooperated to mediating iron metabolism during stress erythropoiesis. Our work revealed a critical role of TET2-mediated DNA demethylation against oxidative stress, and provided the molecular mechanisms underlying the epigenetic regulation of iron homeostasis in response to stress erythropoiesis.

Multiple sclerosis is a chronic demyelinating disease of the central nervous system characterised by inflammatory and degenerative changes. It is considered that disease arises from the influence of environmental factors on genetically susceptible individuals. Recent researches, using magnetic resonance imaging, connected iron deposits in different brain regions with demyelinating process in multiple sclerosis patients. Although iron is an essential trace element important for many biological functions it could be harmful because iron excess can induce the production of reactive oxygen species, development of oxidative stress and lipid peroxidation which leads to demyelination. In experimental autoimmune encephalomyelitis model, the most common experimental animal model for multiple sclerosis, we recently found that chronic iron overload influences the clinical course of disease in Dark Agouti rats. In female rats iron overload accelerated the onset of disease, while in male rats it accelerated the progression of disease and increased mortality rate. We hypothesize that those differences arise on molecular level in different expression of stress response proteins hepcidin and metallothioneins in male and female iron overloaded rats. They are both upregulated by metal ions in both sexes. Hepcidin is additionally upregulated by estrogen in female rats and therefore causes higher degradation of iron exporter ferroportin and sequestration of iron in the cells, lowering the possibility for the development of oxidative stress. Antioxidative effect of metallothioneins could be increased in female rats because of their ability to reversibly exchange metal ions with the estrogen receptor. In case of iron excess metallothioneins release zinc, which is normally bound to them. Zinc binds to estrogen receptor and leaves metallothioneins binding domains free for iron, causing at least provisional cytoprotective effect. To test this hypothesis, we propose to determine and compare serum levels of hepcidin and estrogen using ELISA essay as well as expression and distribution of acute stress response proteins hepcidin and metallothioneins, iron and estrogen receptor in the brain and spinal cord tissue using immunohistochemistry in control and chronic iron overloaded male and female rats in experimental autoimmune encephalomyelitis model. It would be also possible to perform the same immunohistochemistry in the brain tissue of multiple sclerosis patients post mortem. The results of experiments could contribute to better understanding of cytoprotective mechanisms in chronic iron overload that could have possible therapeutic applications in iron disturbances. In order to elucidate whether common measure of systemic iron status, like ferritin, haemoglobin concentration and transferrin saturation levels, may be used to distinguish physiologic from potentially harmful iron levels in local disease, for example multiple sclerosis and Still's disease, well-designed clinical trials would be of great interest.

Iron is required for hemoglobin production, and it plays a key role during erythropoiesis. Systemic iron homeostasis is mainly negatively regulated by the peptide hormone hepcidin, coded by the gene HAMP. Hepcidin excess may cause iron deficiency, iron-restricted erythropoiesis, and anemia. Conversely, hepcidin insufficiency leads to iron overload and oxidative damage in multiple tissues. During regulation of hepcidin synthesis, multiple promoter elements in the HAMP gene respond to variable signaling pathways corresponding to different extracellular situations. It has been reported that hepcidin expression can be suppressed by secreted erythroid factors, including GDF15, TWSG1, GDF11, and ERFE, thereby increasing iron availability for hemoglobin synthesis. These potential erythroid factors act via intricate mechanisms that remain controversial. However, it is clear that hepcidin affects erythropoiesis, and promising therapies targeting hepcidin have been developed to treat erythroid disorders. These therapeutic strategies include suppressing or activating HAMP gene expression, mimicking or activating hepcidin activity, and blocking the ability of hepcidin to bind to its target ferroportin.

Eukaryotic cells contain hundreds of metalloproteins that are supported by intracellular systems coordinating the uptake and distribution of metal cofactors. Iron cofactors include heme, iron-sulfur clusters, and simple iron ions. Poly(rC)-binding proteins are multifunctional adaptors that serve as iron ion chaperones in the cytosolic/nuclear compartment, binding iron at import and delivering it to enzymes, for storage (ferritin) and export (ferroportin). Ferritin iron is mobilized by autophagy through the cargo receptor, nuclear co-activator 4. The monothiol glutaredoxin Glrx3 and BolA2 function as a [2Fe-2S] chaperone complex. These proteins form a core system of cytosolic iron cofactor chaperones in mammalian cells.

Mosaic mutant mice displaying functional dysfunction of Atp7a copper transporter (the Menkes ATPase) are an established animal model of Menkes disease and constitute a convenient tool for investigating connections between copper and iron metabolisms. This model allows to explore changes in iron metabolism in suckling mutant mice suffering from systemic copper deficiency as well as in young and adult ones undergone copper therapy, which reduces lethal effect of the Atp7a gene mutation. Our recent study demonstrated that 14-day-old mosaic mutant males display blood cell abnormalities associated with intravascular hemolysis, and show disturbances in the functioning of the hepcidin-ferroportin regulatory axis, which controls systemic iron homeostasis. We thus aimed to check whether copper supplementation recovers mutants from hemolytic insult and rebalance systemic iron regulation. Copper supplementation of 14-day-old mosaic mutants resulted in the reestablishment of hematological status, attenuation of hepicidin and concomitant induction of the iron exporter ferroportin/Slc40a1 expression in the liver, down-regulated in untreated mutants. Interestingly, treatment of wild-type males with copper, induced hepcidin-independent up-regulation of ferroportin protein level in hepatic macrophages in both young and adult (6-month-old) animals. Stimulatory effect of copper on ferroportin mRNA and protein levels was confirmed in bone marrow-derived macrophages isolated from both wild-type and mosaic mutant males. Our study indicates that copper is an important player in the regulation of the Slc40a1 gene expression.

Emerging evidence suggests that pulmonary iron accumulation is implicated in a spectrum of chronic lung diseases. However, the mechanism(s) involved in pulmonary iron deposition and its role in the in vivo pathogenesis of lung diseases remains unknown. Here we show that a point mutation in the murine ferroportin gene, which causes hereditary hemochromatosis type 4 (Slc40a1C326S), increases iron levels in alveolar macrophages, epithelial cells lining the conducting airways and lung parenchyma, and in vascular smooth muscle cells. Pulmonary iron overload is associated with oxidative stress, restrictive lung disease with decreased total lung capacity and reduced blood oxygen saturation in homozygous Slc40a1C326S/C326S mice compared to wild-type controls. These findings implicate iron in lung pathology, which is so far not considered a classical iron-related disorder.

This study aimed to evaluate the effect of sorghum and sweet potato on the bioavailability of iron, gene expression of proteins involved in iron metabolism and the plasma antioxidant capacity in animals fed with whole sorghum grains processed by dry heat or extrusion, combined or not with sweet potato flour with high content of carotenoids. Five experimental groups were tested (n = 7): dry heat sorghum flour (DS); extruded sorghum flour (ES); whole sorghum flour + sweet potato flour (DS + SP); extruded sorghum flour + sweet potato flour (ES + SP) and positive control (FS). The evaluations included: hemoglobin gain, hemoglobin regeneration efficiency, gene expression of divalente metal transporter 1 (DMT-1), duodenal citochroma B (DcytB), ferroportin, hephaestin, transferrin and ferritin and total plasma antioxidant capacity (TAC). The ES + SP group showed higher (p

Impaired iron homeostasis and the suppressive effects of proinflammatory cytokines on erythropoiesis, together with alterations of the erythrocyte membrane that impair its survival, cause anemia of inflammation. Recent epidemiologic studies have connected inflammatory anemia with critical illness, obesity, aging, kidney failure, cancer, chronic infection, and autoimmune disease. The proinflammatory cytokine, interleukin-6, the iron regulatory hormone, hepcidin, and the iron exporter, ferroportin, interact to cause iron sequestration in the setting of inflammation. Although severe anemia is associated with adverse outcomes in critical illness, experimental models suggest that iron sequestration is part of a natural defense against pathogens.

Hepcidin is the main regulator of iron metabolism and a pathogenic factor in iron disorders. Hepcidin deficiency causes iron overload, whereas hepcidin excess causes or contributes to the development of iron-restricted anaemia in chronic inflammatory diseases. We know the mechanisms involved in the synthesis of hepcidin and, under physiological conditions, there is a balance between activating signals and inhibitory signals that regulate its synthesis. The former include those related to plasmatic iron level and also those related to chronic inflammatory diseases. The most important inhibitory signals are related to active erythropoiesis and to matriptase-2. Knowing how hepcidin is synthesised has helped design new pharmacological treatments whose main target is the hepcidin. In the near future, there will be effective treatments aimed at correcting the defect of many of these iron metabolism disorders.

Iron is an essential biogenic element for both prokaryotic and eukaryotic cells. In humans iron is present in hundreds of different metalloproteins. The peptide hormone hepcidin serves as a master regulator of iron homeostasis on the level of single cells and whole organism - by altering cell surface expression of cellular iron exporter - protein ferroportin. Altered levels of extracellular hepcidin lead to pathological conditions such as hemochromatosis and iron loading or, on the other side, iron restrictive anemias. Therapeutic modulation of hepcidin is a new and promising approach to treatment of these conditions. In this review, a summary of the current knowledge of hepcidin function, regulation and pathological involvements are provided, followed by a section covering the therapeutic potential of hepcidin and the current strategies how to modulate its levels and biological functions for therapeutic purposes.

[Objective] To explore the relationship between iron and infertility by investigating iron-related gene expression in granulosa and uterine cervical cells., [Design] Case-control study., [Setting] Two tertiary hospitals., [Patient(s)] Two independent cohorts of fertile (n = 18 and n = 17) and infertile (n = 31 and n = 35) women., [Intervention(s)] In vitro fertilization., [Main Outcome Measure(s)] Gene expression levels of ferritin light chain (FTL), ferritin heavy chain (FTH), transferrin receptor (TFRC), and ferroportin (SLC40A1) mRNA were analyzed in granulosa and cervical cells., [Result(s)] In the first cohort, fertile and infertile women were similar in body mass index. Ferroportin mRNA levels were decreased in granulosa cells from infertile women in parallel with increased serum hepcidin levels. A positive association between ferroportin and TFRC mRNA, a gene associated with intracellular iron deficiency, was observed only in granulosa cells from fertile women. The major findings were replicated in a second independent cohort., [Conclusion(s)] Ferroportin mRNAs and circulating hepcidin identify a subset of infertile women and may constitute a target for therapy.

Introduction Neonatal hemochromatosis (NH) is a rare neonatal disorder that results in liver cirrhosis with hemosiderin deposition in the liver and other organs, similarly to hereditary hemochromatosis. Excess iron is transferred from the mother to fetus through the placenta in NH. We examined the expression of iron metabolism-related substances in placental syncytiotrophoblasts (STB) by immunostaining to clarify how the transfer of iron through STB increases in NH. Methods Immunostaining was performed using formalin-fixed, paraffin-embedded sections of placentae from three NH cases, four gestational age-matched controls, and, depending on the antibody examined, five to seven full-term controls. The reactivity of immunostaining was assessed by averages of scores assigned by 3 researchers. Results On the microvillar surface of STB, the reactions of the antibodies against transferrin receptor 1 (TFR1), transferrin, ferritin, hepcidin, ferroportin, divalent metal transporter-1 (DMT1), hephaestin, and HFE were stronger in NH than in controls. In the cytoplasm, the reactions of antibodies against TFR1, transferrin, ferritin, hepcidin, DMT1, hephaestin, HFE, and ZIP 14 were stronger in NH than in gestational age-matched controls. Among these reactions, those of anti-TFR1 antibody on the surface of STB in NH was especially marked. Discussion In the placenta of NH, increases in expressions of TFR1, transferrin, and ferritin of which those of TFR1 were especially marked, reflect increased iron influx from the mother to fetus. The hepcidin observed on the surface and in the cytoplasm of STB of NH is suggested to be from the mother, possibly to compensate for the decreased fetal liver-derived hepcidin.

There is strong literature support for brain metal dysregulation, oxidative stress and oxidative damage to neurons in Alzheimer's disease (AD); these processes begin early and continue throughout the disease. Here, we review current knowledge on metal dysregulation and nucleic acid oxidative damage in AD (we also include new data demonstrating increased RNA and DNA oxidative damage in hippocampus from individuals having suffered from degenerative (e.g. AD) and psychological diseases: 8-oxo-7,8-dihydroguanine (8-oxoGua) levels as determined by HPLC-EC-UV were particularly elevated in RNA and heterogeneously distributed among adjacent regions versus the control). Whereas neuronal iron accumulation occurs in aging, neuronal iron levels further increase in AD accompanied by oxidative damage, decreased copper levels, amyloid plaque formation and brain inflammation. The 'hepcidin-ferroportin iron overload' AD hypothesis links these processes together and is discussed here. Moreover, we find that most existing transgenic animal AD models only partly involve these processes, rather they are often limited to expression of mutated amyloid beta protein precursor (AbetaPP), presenilin, tau or apolipoprotein E proteins although a few models appear more relevant than others. Relevant models are likely to be crucial for refining and testing this hypothesis as well as developing new drugs.

Prevalences of human herpesvirus-8 (HHV-8) infection and diabetes mellitus are very common in certain parts of Africa, containing iron-rich soils. We hypothesized that some genetic factors could have a link with susceptibility to HHV-8 infection. We focused on ferroportin Q248H mutation (rs11568350), transferrin (TF) polymorphism and fructosamine-3 kinase (FN3K) 900C/G polymorphism (rs1056534). The study population consisted of 210 type 2 diabetic adults and 125 healthy controls recruited in Bukavu (South Kivu). In the whole study population (diabetics+healthy controls), ferroportin Q248H mutation was detected in 47 subjects (14.0%) with 43 heterozygotes and 4 homozygotes. TF phenotype frequencies were 88.1% (CC), 10.4% (CD) and 1.5% (BC). Genotype frequencies of FN3K 900C/G polymorphism were respectively 9,3% (CC), 43.3% (GC) and 47.4% (GG). Prevalence of HHV8-infection in the study population was 77.3%. HHV-8 infection rate and HHV-8 IgG antibody titer were significantly higher in diabetics then in controls (p0.0001). Significant differences were observed in HHV-8 infection rate and in HHV-8 IgG antibody titer according to FN3K rs1056534 (p0.05 and p0.05, respectively) and TF polymorphism (p0.05 and p=0.005, respectively). No significant differences in HHV-8 infection rate and in HHV-8 IgG antibody titer were observed in the ferroportin Q248H mutation carriers (rs11568350) in comparison with ferroportin wild type. In a multiple regression analysis, FN3K rs1056534, TF polymorphism and presence of diabetes mellitus were predictors for HHV-8 infection. In contrast to these findings, ferroportin Q248H mutation (rs11568350) did not influence the susceptibility for an HHV-8 infection in sub-Saharan Africans.