Known and potential roles of transferrin in iron biology. Biometals. 2012;25:677-686. [PMID: 22294463 DOI: 10.1007/s10534-012-9520-3]

Advances of Iron and Ferroptosis in Diabetic Kidney Disease

Diabetes mellitus presents a significant threat to human health because it disrupts energy metabolism and gives rise to various complications, including diabetic kidney disease (DKD). Metabolic adaptations occurring in the kidney in response to diabetes contribute to the pathogenesis of DKD. Iron metabolism and ferroptosis, a recently defined form of cell death resulting from iron-dependent excessive accumulation of lipid peroxides, have emerged as crucial players in the progression of DKD. In this comprehensive review, we highlight the profound impact of adaptive and maladaptive responses regulating iron metabolism on the progression of kidney damage in diabetes. We summarize the current understanding of iron homeostasis and ferroptosis in DKD. Finally, we propose that precise manipulation of iron metabolism and ferroptosis may serve as potential strategies for kidney management in diabetes.

Anemia of Chronic Kidney Disease-A Narrative Review of Its Pathophysiology, Diagnosis, and Management

Anemia is one of the most common chronic kidney disease (CKD) complications. It negatively affects patients' quality of life and clinical outcomes. The pathophysiology of anemia in CKD involves the interplay of various factors such as erythropoietin (EPO) deficiency, iron dysregulation, chronic inflammation, bone marrow dysfunction, and nutritional deficiencies. Despite recent advances in understanding this condition, anemia still remains a serious clinical challenge in population of patients with CKD. Several guidelines have been published with the aim to systematize the diagnostic approach and treatment of anemia; however, due to emerging data, many recommendations vary between publications. Recent studies indicate a potential of novel biomarkers to evaluate anemia and related conditions such as iron deficiency, which is often present in CKD patients. Our article aims to summarize the pathophysiology of anemia in CKD, as well as the diagnosis and management of this condition, including novel therapeutic approaches such as hypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHI). Understanding these complex subjects is crucial for a targeted approach to diagnose and treat patients with anemia in CKD effectively.

Advance in Iron Metabolism, Oxidative Stress and Cellular Dysfunction in Experimental and Human Kidney Diseases

Kidney diseases pose a significant global health issue, frequently resulting in the gradual decline of renal function and eventually leading to end-stage renal failure. Abnormal iron metabolism and oxidative stress-mediated cellular dysfunction facilitates the advancement of kidney diseases. Iron homeostasis is strictly regulated in the body, and disturbance in this regulatory system results in abnormal iron accumulation or deficiency, both of which are associated with the pathogenesis of kidney diseases. Iron overload promotes the production of reactive oxygen species (ROS) through the Fenton reaction, resulting in oxidative damage to cellular molecules and impaired cellular function. Increased oxidative stress can also influence iron metabolism through upregulation of iron regulatory proteins and altering the expression and activity of key iron transport and storage proteins. This creates a harmful cycle in which abnormal iron metabolism and oxidative stress perpetuate each other, ultimately contributing to the advancement of kidney diseases. The crosstalk of iron metabolism and oxidative stress involves multiple signaling pathways, such as hypoxia-inducible factor (HIF) and nuclear factor erythroid 2-related factor 2 (Nrf2) pathways. This review delves into the functions and mechanisms of iron metabolism and oxidative stress, along with the intricate relationship between these two factors in the context of kidney diseases. Understanding the underlying mechanisms should help to identify potential therapeutic targets and develop novel and effective therapeutic strategies to combat the burden of kidney diseases.

The effect of red blood cell disorders on male fertility and reproductive health

Male infertility is defined as a failure to conceive after 12 months of unprotected intercourse owing to suspected male reproductive factors. Non-malignant red blood cell disorders are systemic conditions that have been associated with male infertility with varying severity and strength of evidence. Hereditary haemoglobinopathies and bone marrow failure syndromes have been associated with hypothalamic-pituitary-gonadal axis dysfunction, hypogonadism, and abnormal sperm parameters. Bone marrow transplantation is a potential cure for these conditions, but exposes patients to potentially gonadotoxic chemotherapy and/or radiation that could further impair fertility. Iron imbalance might also reduce male fertility. Thus, disorders of hereditary iron overload can cause iron deposition in tissues that might result in hypogonadism and impaired spermatogenesis, whereas severe iron deficiency can propagate anaemias that decrease gonadotropin release and sperm counts. Reproductive urologists should be included in the comprehensive care of patients with red blood cell disorders, especially when gonadotoxic treatments are being considered, to ensure fertility concerns are appropriately evaluated and managed.

A nomogram for predicting the risk of treatment failure of roxadustat in peritoneal dialysis with renal anemia

The determinants of roxadustat treatment failure in renal anemia remain elusive. This study sought to develop a nomogram for predicting the risk of treatment failure of roxadustat in peritoneal dialysis (PD) with renal anemia. A retrospective cohort analysis from January 1, 2019, to January 31, 2023, included 204 PD patients with renal anemia, stratified by attainment group (Hb ≥ 110 g/L, n = 103) or non-attainment (Hb < 110 g/L, n = 101) within 1 year treatment. Univariate and multivariate Cox proportional hazards regressions were employed to ascertain predictive factors and construct the nomogram. Nomogram efficacy was evaluated via C-index, time-dependent ROC, calibration plots, and decision curve analysis, with internal validation via tenfold cross-validation and 1000 bootstrap resampling iterations. The study identified PD duration, serum transferrin, cardiovascular comorbidities, and stains as significant predictors. The nomogram demonstrated moderate discrimination at 6 months (AUC: 0.717) and enhanced predictive accuracy at 12 months (AUC: 0.741). The predicted and actual risk probabilities were concordant, with clinical net benefits observed at six-month (8 to 53%) and twelve-month (27 to 84%) risk thresholds. This nomogram is a valuable tool for effectively predicting non-attainment risk and facilitating personalized management of renal anemia in PD patients treated with roxadustat.

Role of mineral nutrients other than iron in pregnancy: under recognized opportunities to improve maternal/fetal outcomes: a literature review

BACKGROUND

Anemia during pregnancy is an important global health concern, affecting 40% of women worldwide, and iron deficiency shares a significant proportion of the burden. From conception to birth, pregnancy is a period when women undergo metabolic and physiological changes. The nutritional needs are higher during pregnancy; thus, adequate nutrition is essential to maintain fetal growth and development. However, adverse effects due to deficiency in nutrition during pregnancy can result in maternal, fetal and neonatal complications. Despite the multifactorial etiology of anemia, iron deficiency is assumed as the primary cause of anemia during pregnancy and hence, mitigation strategy pivots around it for anemia management. Therefore, excluding other contributors, a single-micronutrient approach with iron supplements remains a myopic approach and this can exacerbate iron deficiency anemia. Micronutrient deficiencies are of particular concern as they may pose a silent threat to the survival and well-being of reproductive-age women and their infants.

AIM

Micronutrients, especially trace minerals, play a myriad of roles in pregnancy, and the lack of each one causes adverse complications to both the mother and the fetus. In this review paper, we attempt to piece together available information regarding the adverse effects of abnormal trace mineral levels along with iron deficiency on the mother and the fetus.

METHOD

A non-systematic literature search in PubMed, Google Scholar, and the Cochrane databases, for publications on minerals and vitamins during pregnancy and the possible influence of supplements on pregnancy outcomes.

CONCLUSION

Micronutrient deficiency exacerbates the pregnancy-induced anemia and other adverse birth outcomes. Micronutrient supplementation during pregnancy can combat anemia as well as reduce a number of adverse pregnancy outcomes in a comprehensive manner.

Mechanisms controlling cellular and systemic iron homeostasis

In mammals, hundreds of proteins use iron in a multitude of cellular functions, including vital processes such as mitochondrial respiration, gene regulation and DNA synthesis or repair. Highly orchestrated regulatory systems control cellular and systemic iron fluxes ensuring sufficient iron delivery to target proteins is maintained, while limiting its potentially deleterious effects in iron-mediated oxidative cell damage and ferroptosis. In this Review, we discuss how cells acquire, traffick and export iron and how stored iron is mobilized for iron-sulfur cluster and haem biogenesis. Furthermore, we describe how these cellular processes are fine-tuned by the combination of various sensory and regulatory systems, such as the iron-regulatory protein (IRP)-iron-responsive element (IRE) network, the nuclear receptor co-activator 4 (NCOA4)-mediated ferritinophagy pathway, the prolyl hydroxylase domain (PHD)-hypoxia-inducible factor (HIF) axis or the nuclear factor erythroid 2-related factor 2 (NRF2) regulatory hub. We further describe how these pathways interact with systemic iron homeostasis control through the hepcidin-ferroportin axis to ensure appropriate iron fluxes. This knowledge is key for the identification of novel therapeutic opportunities to prevent diseases of cellular and/or systemic iron mismanagement.

Identification of a novel ferroptosis-related gene signature associated with retinal degeneration induced by light damage in mice

Background

Neurodegenerative retinal diseases such as retinitis pigmentosa are serious disorders that may cause irreversible visual impairment. Ferroptosis is a novel type of programmed cell death, and the involvement of ferroptosis in retinal degeneration is still unclear. This study aimed to investigate the related ferroptosis genes in a mice model of retinal degeneration induced by light damage.

Methods

A public dataset of GSE10528 deriving from the Gene Expression Omnibus database was analyzed to identify the differentially expressed genes (DEGs). Gene set enrichment analysis between light damage and control group was conducted. The differentially expressed ferroptosis-related genes (DE-FRGs) were subsequently identified by intersecting the DEGs with a ferroptosis genes dataset retrieved from the FerrDb database. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were further performed using the DE-FRGs. A protein-protein interaction (PPI) network was constructed to identify hub ferroptosis-related genes (HFRGs). The microRNAs (miRNAs)-HFRGs, transcription factors (TFs)-HFRGs networks as well as target drugs potentially interacting with HFRGs were analyzed utilizing bioinformatics algorithms.

Results

A total of 932 DEGs were identified between the light damage and control group. Among these, 25 genes were associated with ferroptosis. GO and KEGG analyses revealed that these DE-FRGs were mainly enriched in apoptotic signaling pathway, response to oxidative stress and autophagy, ferroptosis, necroptosis and cytosolic DNA-sensing pathway. Through PPI network analysis, six hub ferroptosis-related genes (Jun, Stat3, Hmox1, Atf3, Hspa5 and Ripk1) were ultimately identified. All of them were upregulated in light damage retinas, as verified by the GSE146176 dataset. Bioinformatics analyses predicated that 116 miRNAs, 23 TFs and several potential therapeutic compounds might interact with the identified HFRGs.

Conclusion

Our study may provide novel potential biomarkers, therapeutic targets and new insights into the ferroptosis landscape in retinal neurodegenerative diseases.

Reversible atransferrinemia in a patient with chronic enteropathy: is transferrin mandatory for iron transport?

Herein, we report the case of a 42-year-old woman, hospitalized in a French tertiary hospital for a relapse of a chronic enteropathy, who was found on admission to have no detectable serum transferrin. Surprisingly, she only exhibited mild anaemia. This atransferrinemia persisted for two months throughout her hospitalization, during which her haemoglobin concentration remained broadly stable. Based on her clinical history and evolution, we concluded to an acquired atransferrinemia secondary to chronic undernutrition, inflammation and liver failure. We discuss the investigations performed in this patient, and hypotheses regarding the relative stability of her haemoglobin concentration despite the absence of detectable transferrin.

Might nontransferrin-bound iron in blood plasma and sera be a nonproteinaceous high-molecular-mass FeIII aggregate?

The HFE (Homeostatic Fe regulator) gene is commonly mutated in hereditary hemochromatosis. Blood of (HFE)(-/-) mice and of humans with hemochromatosis contains toxic nontransferrin-bound iron (NTBI) which accumulates in organs. However, the chemical composition of NTBI is uncertain. To investigate, HFE(-/-) mice were fed iron-deficient diets supplemented with increasing amounts of iron, with the expectation that NTBI levels would increase. Blood plasma was filtered to obtain retentate and flow-through solution fractions. Liquid chromatography detected by inductively coupled plasma mass spectrometry of flow-through solutions exhibited low-molecular-mass iron peaks that did not increase intensity with increasing dietary iron. Retentates yielded peaks due to transferrin (TFN) and ferritin, but much iron in these samples adsorbed onto the column. Retentates treated with the chelator deferoxamine (DFO) yielded a peak that comigrated with the Fe-DFO complex and originated from iron that adhered to the column in the absence of DFO. Additionally, plasma from younger and older 57Fe-enriched HFE mice were separately pooled and concentrated by ultrafiltration. After removing contributions from contaminating blood and TFN, Mössbauer spectra were dominated by features due to magnetically interacting FeIII aggregates, with greater intensity in the spectrum from the older mice. Similar features were generated by adding 57FeIII to "pseudo plasma". Aggregation was unaffected by albumin or citrate at physiological concentrations, but DFO or high citrate concentrations converted aggregated FeIII into high-spin FeIII complexes. FeIII aggregates were retained by the cutoff membrane and adhered to the column, similar to the behavior of NTBI. A model is proposed in which FeII entering blood is oxidized, and if apo-TFN is unavailable, the resulting FeIII ions coalesce into FeIII aggregates, a.k.a. NTBI.

Perinatal iron deficiency as an early risk factor for schizophrenia

Growing evidence indicates that a suboptimal intrauterine environment confers risk for schizophrenia. The developmental model of schizophrenia posits that aberrant brain growth during early brain development and adolescence may interact to contribute to this psychiatric disease in adulthood. Although a variety of factors may perturb the environment of the developing fetus and predispose for schizophrenia later, a common mechanism has yet to be elucidated. Micronutrient deficiencies during the perinatal period are known to induce potent effects on brain development by altering neurodevelopmental processes. Iron is an important candidate nutrient to consider because of its role in energy metabolism, monoamine synthesis, synaptogenesis, myelination, and the high prevalence of iron deficiency (ID) in the mother-infant dyad. Understanding the current state of science regarding perinatal ID as an early risk factor for schizophrenia is imperative to inform empirical work investigating the etiology of schizophrenia and develop prevention and intervention programs. In this narrative review, we focus on perinatal ID as a common mechanism underlying the fetal programming of schizophrenia. First, we review the neural aberrations associated with perinatal ID that indicate risk for schizophrenia in adulthood, including disruptions in dopaminergic neurotransmission, hippocampal-dependent learning and memory, and sensorimotor gating. Second, we review the pathophysiology of perinatal ID as a function of maternal ID during pregnancy and use epidemiological and cohort studies to link perinatal ID with risk of schizophrenia. Finally, we review potential confounding phenotypes, including nonanemic causes of perinatal brain ID and future risk of schizophrenia.

Shotgun Proteomics for the Identification and Profiling of the Tear Proteome of Keratoconus Patients

Purpose

The qualitative approach followed in this study aims to obtain an extensive view of the keratoconus (KC) tear proteome, which could highlight proteins previously undetected and enlarge our knowledge of the disease's pathophysiology.

Methods

Twenty-five patients diagnosed with KC and 25 control subjects were studied in a prospective, cross-sectional study. KC screening examinations, including clinical and tomographic examinations, were performed on all participants. Tear samples were collected using Schirmer strips and analyzed by liquid chromatography-tandem mass spectrometry in a data-dependent workflow. A spectral count was used as a semiquantification tool. The tear proteomes of both groups were identified and profiled, and the functional interactions and biological characterization of differential proteins were analyzed using in silico tools.

Results

We identified a total of 232 proteins, of whom 133 were expressed in both groups’ samples; 41 were observed only in control samples and 58 were identified just in tears of patients with KC. A semiquantitative analysis showed the dysregulation of 17 proteins in the KC samples. An in silico analysis linked proteins only expressed in KC samples to oxidative stress, skin development, and apoptosis. The dysregulation of proteins involved in iron transport, inflammation, oxidative stress, and protease inhibition was observed in the semiquantitative results.

Conclusions

A shotgun analysis showed that the tear proteome of patients with KC differed from controls by more than one-third of the total proteins identified, highlighting the relationship of the proteins only expressed in KC tears with processes of cell death, oxidative damage, and inflammation. The underexpression of proteins involved in iron pathways might support the iron imbalance as a contributing factor to cellular damage and death in KC disease.

Immunoaffinity Capillary Electrophoresis in the Era of Proteoforms, Liquid Biopsy and Preventive Medicine: A Potential Impact in the Diagnosis and Monitoring of Disease Progression

Over the years, multiple biomarkers have been used to aid in disease screening, diagnosis, prognosis, and response to therapy. As of late, protein biomarkers are gaining strength in their role for early disease diagnosis and prognosis in part due to the advancements in identification and characterization of a distinct functional pool of proteins known as proteoforms. Proteoforms are defined as all of the different molecular forms of a protein derived from a single gene caused by genetic variations, alternative spliced RNA transcripts and post-translational modifications. Monitoring the structural changes of each proteoform of a particular protein is essential to elucidate the complex molecular mechanisms that guide the course of disease. Clinical proteomics therefore holds the potential to offer further insight into disease pathology, progression, and prevention. Nevertheless, more technologically advanced diagnostic methods are needed to improve the reliability and clinical applicability of proteomics in preventive medicine. In this manuscript, we review the use of immunoaffinity capillary electrophoresis (IACE) as an emerging powerful diagnostic tool to isolate, separate, detect and characterize proteoform biomarkers obtained from liquid biopsy. IACE is an affinity capture-separation technology capable of isolating, concentrating and analyzing a wide range of biomarkers present in biological fluids. Isolation and concentration of target analytes is accomplished through binding to one or more biorecognition affinity ligands immobilized to a solid support, while separation and analysis are achieved by high-resolution capillary electrophoresis (CE) coupled to one or more detectors. IACE has the potential to generate rapid results with significant accuracy, leading to reliability and reproducibility in diagnosing and monitoring disease. Additionally, IACE has the capability of monitoring the efficacy of therapeutic agents by quantifying companion and complementary protein biomarkers. With advancements in telemedicine and artificial intelligence, the implementation of proteoform biomarker detection and analysis may significantly improve our capacity to identify medical conditions early and intervene in ways that improve health outcomes for individuals and populations.

Cell Ferroptosis: New Mechanism and New Hope for Retinitis Pigmentosa

Retinitis pigmentosa (RP) is a leading cause of inherited retinal degeneration, with more than 60 gene mutations. Despite the genetic heterogenicity, photoreceptor cell damage remains the hallmark of RP pathology. As a result, RP patients usually suffer from reduced night vision, loss of peripheral vision, decreased visual acuity, and impaired color perception. Although photoreceptor cell death is the primary outcome of RP, the underlying mechanisms are not completely elucidated. Ferroptosis is a novel programmed cell death, with characteristic iron overload and lipid peroxidation. Recent studies, using in vitro and in vivo RP models, discovered the involvement of ferroptosis-associated cell death, suggesting a possible new mechanism for RP pathogenesis. In this review, we discuss the association between ferroptosis and photoreceptor cell damage, and its implication in the pathogenesis of RP. We propose that ferroptotic cell death not only opens up a new research area in RP, but may also serve as a novel therapeutic target for RP.

Vanadium Decreases Hepcidin mRNA Gene Expression in STZ-Induced Diabetic Rats, Improving the Anemic State

Diabetes is a disease with an inflammatory component that courses with an anemic state. Vanadium (V) is an antidiabetic agent that acts by stimulating insulin signaling. Hepcidin blocks the intestinal absorption of iron and the release of iron from its deposits. We aim to investigate the effect of V on hepcidin mRNA expression and its consequences on the hematological parameters in streptozotocin-induced diabetic Wistar rats. Control healthy rats, diabetic rats, and diabetic rats treated with 1 mgV/day were examined for five weeks. The mineral levels were measured in diet and serum samples. Hepcidin expression was quantified in liver samples. Inflammatory and hematological parameters were determined in serum or whole blood samples. The inflammatory status was higher in diabetic than in control rats, whereas the hematological parameters were lower in the diabetic rats than in the control rats. Hepcidin mRNA expression was significantly lower in the V-treated diabetic rats than in control and untreated diabetic rats. The inflammatory status remained at a similar level as the untreated diabetic group. However, the hematological profile improved after the V-treatment, reaching similar levels to those found in the control group. Serum iron level was higher in V-treated than in untreated diabetic rats. We conclude that V reduces gene expression of hepcidin in diabetic rats, improving the anemic state caused by diabetes.

Fetal-fluid proteome analyses in late-term healthy pregnant mares and in mares with experimentally induced ascending placentitis

Characterisation of fetal fluids in healthy and disease states of pregnant mares can help to unravel the pathophysiology and to identify putative markers of disease. Thus, this study aimed to compare the protein composition of: (1) amniotic and allantoic fluids of healthy mares obtained immediately after euthanasia and (2) allantoic fluid harvested via centesis before and after experimental induction of placentitis via transcervical inoculation of Streptococcus equi ssp zooepidemicus in healthy mares. Fetal fluids were analysed with a high-throughput proteomic technique after in-gel digestion. Statistical comparisons were performed following normalisation of peptide spectral match. Global normalisation was performed to calculate relative expression. There were 112 unique proteins present in both allantoic and amniotic fluids. There were 13 and 29 proteins defined as amniotic- or allantoic-specific respectively that were present in at least two fluid samples. Another 26 proteins were present in both amniotic and allantoic fluids. Panther DB functional classification grouped fetal-fluid proteins as transfer carriers, signalling molecules, receptors, immunity, hydrolase, enzymes, membrane traffic, cytoskeleton, cell adhesion, calcium binding and extracellular matrix. Experimentally induced placentitis resulted in 10 proteins being upregulated and 10 downregulated in allantoic fluid. Newly identified proteins and changes in the fetal-fluid proteome provide clues about the physiology of pregnancy and pathogenesis of placentitis.

The Role of Fe, Zn, and Cu in Pregnancy

Iron (Fe), copper (Cu), and zinc (Zn) are microelements essential for the proper functioning of living organisms. These elements participatein many processes, including cellular metabolism and antioxidant and anti-inflammatory defenses, and also influence enzyme activity, regulate gene expression, and take part in protein synthesis. Fe, Cu, and Zn have a significant impact on the health of pregnant women and in the development of the fetus, as well as on the health of the newborn. A proper concentration of these elements in the body of women during pregnancy reduces the risk of complications such as anemia, induced hypertension, low birth weight, preeclampsia, and postnatal complications. The interactions between Fe, Cu, and Zn influence their availability due to their similar physicochemical properties. This most often occurs during intestinal absorption, where metal ions compete for binding sites with transport compounds. Additionally, the relationships between these ions have a great influence on the course of reactions in the tissues, as well as on their excretion, which can be stimulated or delayed. This review aims to summarize reports on the influence of Fe, Cu, and Zn on the course of single and multiple pregnancies, and to discuss the interdependencies and mechanisms occurring between Fe, Cu, and Zn.

Interactions between iron and manganese in neurotoxicity

The essential and naturally occurring transition metal manganese (Mn) is present in the soil, water, air, and various foods. Manganese can accumulate in the brain if the Mn intake or exposure is excessive and this can result in neurotoxic effects. Manganese is important for the proper activation of different metabolic and antioxidant enzymes. There are numerous Mn importers and exporters. However, the exact transport mechanism for Mn is not fully understood. On the other hand, iron (Fe) is another well-known essential metal, which has redox activity in addition to chemical characteristics resembling those of Mn. Existing data show that interactions occur between Fe and Mn due to certain similarities regarding their mechanisms of the absorption and the transport. It has been disclosed that Mn-specific transporters, together with Fe transporters, regulate the Mn distribution in the brain and other peripheral tissues. In PC12 cells, a significant increase of transferrin receptor (TfR) mRNA expression was linked to Mn exposure and accompanied by elevated Fe uptake. In both humans and animals, there is a strong relationship between Fe and Mn metabolism. In the present review, special attention is paid to the interaction between Mn and Fe. In particular, Fe and Mn distribution, as well as the potential molecular mechanisms of Mn-induced neurotoxicity in cases of Fe deficiency, are discussed.

In-depth proteome analysis of more than 12,500 proteins in buffalo mammary epithelial cell line identifies protein signatures for active proliferation and lactation

The mature mammary gland is made up of a network of ducts that terminates in alveoli. The innermost layer of alveoli is surrounded by the differentiated mammary epithelial cells (MECs), which are responsible for milk synthesis and secretion during lactation. However, the MECs are in a state of active proliferation during pregnancy, when they give rise to network like structures in the mammary gland. Buffalo (Bubalus bubalis) constitute a major source of milk for human consumption, and the MECs are the major precursor cells which are mainly responsible for their lactation potential. The proteome of MECs defines their functional state and suggests their role in various cellular activities such as proliferation and lactation. To date, the proteome profile of MECs from buffalo origin is not available. In the present study, we have profiled in-depth proteome of in vitro cultured buffalo MECs (BuMECs) during active proliferation using high throughput tandem mass spectrometry (MS). MS analysis identified a total of 8330, 5970, 5289, 4818 proteins in four sub-cellular fractions (SCFs) that included cytosolic (SCF-I), membranous and membranous organelle’s (SCF-II), nuclear (SCF-III), and cytoskeletal (SCF-IV). However, 792 proteins were identified in the conditioned media, which represented the secretome. Altogether, combined analysis of all the five fractions (SCFs- I to IV, and secretome) revealed a total of 12,609 non-redundant proteins. The KEGG analysis suggested that these proteins were associated with 325 molecular pathways. Some of the highly enriched molecular pathways observed were metabolic, MAPK, PI3-AKT, insulin, estrogen, and cGMP-PKG signalling pathway. The newly identified proteins in this study are reported to be involved in NOTCH signalling, transport and secretion processes.

Iron Metabolism and Brain Development in Premature Infants

Iron is important for a remarkable array of essential functions during brain development, and it needs to be provided in adequate amounts, especially to preterm infants. In this review article, we provide an overview of iron metabolism and homeostasis at the cellular level, as well as its regulation at the mRNA translation level, and we emphasize the importance of iron for brain development in fetal and early life in preterm infants. We also review the risk factors for disrupted iron metabolism that lead to high risk of developing iron deficiency and subsequent adverse effects on neurodevelopment in preterm infants. At the other extreme, iron overload, which is usually caused by excess iron supplementation in iron-replete preterm infants, might negatively impact brain development or even induce brain injury. Maintaining the balance of iron during the fetal and neonatal periods is important, and thus iron status should be monitored routinely and evaluated thoroughly during the neonatal period or before discharge of preterm infants so that iron supplementation can be individualized.

Transferrin receptor 1 controls systemic iron homeostasis by fine-tuning hepcidin expression to hepatocellular iron load

Transferrin receptor 1 (Tfr1) mediates uptake of circulating transferrin-bound iron to developing erythroid cells and other cell types. Its critical physiological function is highlighted by the embryonic lethal phenotype of Tfr1-knockout (Tfrc^-/-) mice and the pathologies of several tissue-specific knockouts. We generated Tfrc^Alb-Cre mice bearing hepatocyte-specific ablation of Tfr1 to explore implications in hepatocellular and systemic iron homeostasis. Tfrc^Alb-Cre mice are viable and do not display any apparent liver pathology. Nevertheless, their liver iron content (LIC) is lower compared with that of control Tfrc^fl/fl littermates as a result of the reduced capacity of Tfr1-deficient hepatocytes to internalize iron from transferrin. Even though liver Hamp messenger RNA (mRNA) and serum hepcidin levels do not differ between Tfrc^Alb-Cre and Tfrc^fl/fl mice, Hamp/LIC and hepcidin/LIC ratios are significantly higher in the former. Importantly, this is accompanied by modest hypoferremia and microcytosis, and it predisposes Tfrc^Alb-Cre mice to iron-deficiency anemia. Tfrc^Alb-Cre mice appropriately regulate Hamp expression following dietary iron manipulations or holo-transferrin injection. Holo-transferrin also triggers proper induction of Hamp mRNA, ferritin, and Tfr2 in primary Tfrc^Alb-Cre hepatocytes. We further show that these cells can acquire ⁵⁹Fe from ⁵⁹Fe-transferrin, presumably via Tfr2. We conclude that Tfr1 is redundant for basal hepatocellular iron supply but essential for fine-tuning hepcidin responses according to the iron load of hepatocytes. Our data are consistent with an inhibitory function of Tfr1 on iron signaling to hepcidin via its interaction with Hfe. Moreover, they highlight hepatocellular Tfr1 as a link between cellular and systemic iron-regulatory pathways.

Acute and Chronic Iron Overloading Differentially Modulates the Expression of Cellular Iron-homeostatic Molecules in Normal Rat Kidney

Little is known about the renal responses to acute iron overloading. This study measured the renal tubular expression of transferrin receptor-1 (TfR1), cubilin/megalin receptors, hepcidin, ferroportin, and ferritin chains following subacute intoxication of 40 male Wistar rats with a single oral dose of ferrous iron (300 mg/kg). The animals were randomly subdivided into 4 equal subgroups at the time of necropsy (1, 2, 4, and 8 hr). The results were compared with the controls ( n=15) and with the chronic group ( n=15), which received iron for 4 weeks (75 mg/kg/day; 5 days/week). Although both toxicity models inhibited TfR1, they upregulated the cubilin/megalin receptors and hepcidin, and triggered iron deposition in tubular cells. The ferritin heavy-chain and ferroportin were downregulated in the 2-hr and 4-hr acute subgroups, whereas chronic toxicity promoted their expression, compared with controls. Moreover, the 4-hr and 8-hr subgroups had higher intracellular Fe⁺² and marked cell apoptosis compared with the chronic group. In conclusion, the kidney appears to sustain iron reabsorption in both intoxication models. However, the cellular iron storage and exporter proteins were differentially expressed in both models, and their inhibition post-acute toxicity might contribute toward the intracellular accumulation of Fe⁺², oxidative stress, and ferroptosis.

Crossing the Iron Gate: Why and How Transferrin Receptors Mediate Viral Entry

Because both the host and pathogen require iron, the innate immune response carefully orchestrates control over iron metabolism to limit its availability during times of infection. Nutritional iron deficiency can impair host immunity, while iron overload can cause oxidative stress to propagate harmful viral mutations. An emerging enigma is that many viruses use the primary gatekeeper of iron metabolism, the transferrin receptor, as a means to enter cells. Why and how this iron gate is a viral target for infection are the focus of this review.

Haemochromatosis

Haemochromatosis is defined as systemic iron overload of genetic origin, caused by a reduction in the concentration of the iron regulatory hormone hepcidin, or a reduction in hepcidin-ferroportin binding. Hepcidin regulates the activity of ferroportin, which is the only identified cellular iron exporter. The most common form of haemochromatosis is due to homozygous mutations (specifically, the C282Y mutation) in HFE, which encodes hereditary haemochromatosis protein. Non-HFE forms of haemochromatosis due to mutations in HAMP, HJV or TFR2 are much rarer. Mutations in SLC40A1 (also known as FPN1; encoding ferroportin) that prevent hepcidin-ferroportin binding also cause haemochromatosis. Cellular iron excess in HFE and non-HFE forms of haemochromatosis is caused by increased concentrations of plasma iron, which can lead to the accumulation of iron in parenchymal cells, particularly hepatocytes, pancreatic cells and cardiomyocytes. Diagnosis is noninvasive and includes clinical examination, assessment of plasma iron parameters, imaging and genetic testing. The mainstay therapy is phlebotomy, although iron chelation can be used in some patients. Hepcidin supplementation might be an innovative future approach.

Addition of oral iron to plasma transfusion in human congenital hypotransferrinemia: A 10-year observational follow-up with the effects on hematological parameters and growth

Congenital hypotransferrinemia (OMIM 209300) is an extremely rare disorder of inherited iron metabolism. Since its description in 1961, only 16 cases have been reported. The defective gene and molecular defect causing this disorder and clinicolaboratory findings seen in the homozygous and heterozygous states have been documented in both humans and mice. However, due to the lack of follow-up studies of the described cases, the long-term prognosis remains unknown. We present a 10-year observational follow-up of a patient previously diagnosed on a molecular basis who was treated with a unique therapy of plasma transfusion fortified with oral iron, with satisfactory clinicolaboratory responses.

The ironclad truth: how in vivo transcriptomics and in vitro mechanistic studies shape our understanding of Neisseria gonorrhoeae gene regulation during mucosal infection

Neisseria gonorrhoeae is one of the most prevalent sexually transmitted infections worldwide. This obligate human pathogen has been extensively studied in vitro, where bacterial factors that are known to contribute to gonococcal disease and their regulation are relatively well defined. However, these in vitro experimental conditions only loosely replicate the host specific environment encountered by the bacteria in vivo. We recently reported on the complete gonococcal transcriptome expressed during natural human mucosal infection using RNA-seq analysis. Gene transcripts expressed in vivo (in vivo expressed factors) included genes encoding antibiotic resistance determinants, and a large number of hypothetical genes. A comparison of the gonococcal transcriptome expressed in vivo with the corresponding strain grown in vitro identified sets of genes regulated by infection, including those regulated by iron and the transcriptional regulatory protein Fur. We highlight here the role of Fur and gonococcal-specific regulatory processes important for infection and pathogenicity. We have determined that the genes controlled by Fur follow the same expression pattern in vivo as described previously in vitro, confirming Fur's regulatory role during infection. Collectively, these studies provide new insights into how bacterial fitness and pathogenicity are modulated during human mucosal infection.

Iron Acquisition Strategies of Bacterial Pathogens

Iron is an essential micronutrient for both microbes and humans alike. For well over half a century we have known that this element, in particular, plays a pivotal role in health and disease and, most especially, in shaping host-pathogen interactions. Intracellular iron concentrations serve as a critical signal in regulating the expression not only of high-affinity iron acquisition systems in bacteria, but also of toxins and other noted virulence factors produced by some major human pathogens. While we now are aware of many strategies that the host has devised to sequester iron from invading microbes, there are as many if not more sophisticated mechanisms by which successful pathogens overcome nutritional immunity imposed by the host. This review discusses some of the essential components of iron sequestration and scavenging mechanisms of the host, as well as representative Gram-negative and Gram-positive pathogens, and highlights recent advances in the field. Last, we address how the iron acquisition strategies of pathogenic bacteria may be exploited for the development of novel prophylactics or antimicrobials.

Interactions of iron with manganese, zinc, chromium, and selenium as related to prophylaxis and treatment of iron deficiency

Iron (Fe) deficiency is considered as the most common nutritional deficiency. Iron deficiency is usually associated with low Fe intake, blood loss, diseases, poor absorption, gastrointestinal parasites, or increased physiological demands as in pregnancy. Nutritional Fe deficiency is usually treated with Fe tablets, sometimes with Fe-containing multimineral tablets. Trace element interactions may have a significant impact on Fe status. Existing data demonstrate a tight interaction between manganese (Mn) and Fe, especially in Fe-deficient state. The influence of Mn on Fe homeostasis may be mediated through its influence on Fe absorption, circulating transporters like transferrin, and regulatory proteins. The existing data demonstrate that the influence of zinc (Zn) on Fe status may be related to their competition for metal transporters. Moreover, Zn may be involved in regulation of hepcidin production. At the same time, human data on the interplay between Fe and Zn especially in terms of Fe-deficiency and supplementation are contradictory, demonstrating both positive and negative influence of Zn on Fe status. Numerous data also demonstrate the possibility of competition between Fe and chromium (Cr) for transferrin binding. At the same time, human data on the interaction between these metals are contradictory. Therefore, while managing hypoferremia and Fe-deficiency anemia, it is recommended to assess the level of other trace elements in parallel with indices of Fe homeostasis. It is supposed that simultaneous correction of trace element status in Fe deficiency may help to decrease possible antagonistic or increase synergistic interactions.

Management of human factors engineering-associated hemochromatosis: A 2015 update

This review focuses on the management of iron metabolism and iron overload experienced in the hereditary condition, human factors engineering (HFE)-associated hemochromatosis. Hemochromatosis refers to a group of genetic diseases that result in iron overload; the major one globally is HFE-associated hemochromatosis. The evolution in understanding of the most common form of hereditary hemochromatosis, being the substation of cysteine to a tyrosine at position 282 in the HFE gene, has been extensively studied Novel mutations in both HFE and non-HFE genes have been indicated in this disease which hold significance in its application for the Asia-Pacific region. In conditions with iron overload, the storage of excess iron in various body tissues leads to complications and toxic damage. The most common presenting complaint for this disease is malaise, lethargy and other non-specific symptoms. In order to diagnose hereditary hemochromatosis, there are biochemical, imaging and genetic testing options. Currently, cascade screening of affected families is preferred over population-level screening. The mainstay of treatment is venesection and the appropriate approach to treatment has been consolidated over the years. Recently, the indications for venesection therapy of hemochromatosis have been challenged and are the subject of ongoing research.

Hepatocyte Nuclear Factor 4α Controls Iron Metabolism and Regulates Transferrin Receptor 2 in Mouse Liver

Iron is an essential element in biological systems, but excess iron promotes the formation of reactive oxygen species, resulting in cellular toxicity. Several iron-related genes are highly expressed in the liver, a tissue in which hepatocyte nuclear factor 4α (HNF4α) plays a critical role in controlling gene expression. Therefore, the role of hepatic HNF4α in iron homeostasis was examined using liver-specific HNF4α-null mice (Hnf4a^ΔH mice). Hnf4a^ΔH mice exhibit hypoferremia and a significant change in hepatic gene expression. Notably, the expression of transferrin receptor 2 (Tfr2) mRNA was markedly decreased in Hnf4a^ΔH mice. Promoter analysis of the Tfr2 gene showed that the basal promoter was located at a GC-rich region upstream of the transcription start site, a region that can be transactivated in an HNF4α-independent manner. HNF4α-dependent expression of Tfr2 was mediated by a proximal promoter containing two HNF4α-binding sites located between the transcription start site and the translation start site. Both the GC-rich region of the basal promoter and the HNF4α-binding sites were required for maximal transactivation. Moreover, siRNA knockdown of HNF4α suppressed TFR2 expression in human HCC cells. These results suggest that Tfr2 is a novel target gene for HNF4α, and hepatic HNF4α plays a critical role in iron homeostasis.

Macrophages and iron trafficking at the birth and death of red cells

Macrophages play a critical role in iron homeostasis via their intimate association with developing and dying red cells. Central nurse macrophages promote erythropoiesis in the erythroblastic island niche. These macrophages make physical contact with erythroblasts, enabling signaling and the transfer of growth factors and possibly nutrients to the cells in their care. Human mature red cells have a lifespan of 120 days before they become senescent and again come into contact with macrophages. Phagocytosis of red blood cells is the main source of iron flux in the body, because heme must be recycled from approximately 270 billion hemoglobin molecules in each red cell, and roughly 2 million senescent red cells are recycled each second. Here we will review pathways for iron trafficking found at the macrophage-erythroid axis, with a focus on possible roles for the transport of heme in toto.

Ferroportin deficiency impairs manganese metabolism in flatiron mice

We examined the physiologic role of ferroportin (Fpn) in manganese (Mn) export using flatiron (ffe/+) mice, a genetic model of Fpn deficiency. Blood (0.0123 vs. 0.0107 mg/kg; P = 0.0003), hepatic (1.06 vs. 0.96 mg/kg; P = 0.0125), and bile Mn levels (79 vs. 38 mg/kg; P = 0.0204) were reduced in ffe/+ mice compared to +/+ controls. Erythrocyte Mn-superoxide dismutase was also reduced at 6 (0.154 vs. 0.096, P = 0.0101), 9 (0.131 vs. 0.089, P = 0.0162), and 16 weeks of age (0.170 vs. 0.090 units/mg protein/min; P < 0.0001). (54)Mn uptake after intragastric gavage was markedly reduced in ffe/+ mice (0.0187 vs. 0.0066% dose; P = 0.0243), while clearance of injected isotope was similar in ffe/+ and +/+ mice. These values were compared to intestinal absorption of (59)Fe, which was significantly reduced in ffe/+ mice (8.751 vs. 3.978% dose; P = 0.0458). The influence of the ffe mutation was examined in dopaminergic SH-SY5Y cells and human embryonic HEK293T cells. While expression of wild-type Fpn reversed Mn-induced cytotoxicity, ffe mutant H32R failed to confer protection. These combined results demonstrate that Fpn plays a central role in Mn transport and that flatiron mice provide an excellent genetic model to explore the role of this exporter in Mn homeostasis. -

Macrophages and iron trafficking at the birth and death of red cells

Macrophages play a critical role in iron homeostasis via their intimate association with developing and dying red cells. Central nurse macrophages promote erythropoiesis in the erythroblastic island niche. These macrophages make physical contact with erythroblasts, enabling signaling and the transfer of growth factors and possibly nutrients to the cells in their care. Human mature red cells have a lifespan of 120 days before they become senescent and again come into contact with macrophages. Phagocytosis of red blood cells is the main source of iron flux in the body, because heme must be recycled from approximately 270 billion hemoglobin molecules in each red cell, and roughly 2 million senescent red cells are recycled each second. Here we will review pathways for iron trafficking found at the macrophage-erythroid axis, with a focus on possible roles for the transport of heme in toto.

Recent advances in hemochromatosis: a 2015 update : a summary of proceedings of the 2014 conference held under the auspices of Hemochromatosis Australia

This review focuses on iron metabolism, the genetics of hemochromatosis, current treatment protocols and various screening methods. Even though the most common form of hereditary hemochromatosis, C282Y gene mutations in the HFE gene, has been extensively studied, novel mutations in both HFE and non-HFE genes have been implicated in this disease. These have important implications for the Asia-Pacific region. In overload, deposition of iron in various body tissues leads to toxic damage. Patients commonly present with non-specific symptoms of malaise and lethargy. Biochemical, imaging and genetic testing can be carried out to confirm diagnosis. Venesection forms the mainstay of treatment and at present cascade screening of affected families is recommended over population-level screening.

Maternal perinatal undernutrition modifies lactose and serotranferrin in milk: relevance to the programming of metabolic diseases?

A close link between intrauterine growth restriction and development of chronic adult diseases such as obesity, diabetes, and hypertension has been established both in humans and animals. Modification of growth velocity during the early postnatal period (i.e., lactation) may also sensitize to the development of metabolic syndrome in adulthood. This suggests that milk composition may have long-lasting programming/deprogramming metabolic effects in the offspring. We therefore assess the effects of maternal perinatal denutrition on breast milk composition in a food-restricted 50% (FR50) rat model. Monosaccharides and fatty acids were characterized by gas chromatography, and proteins were profiled by surface-enhanced laser desorption/ionization-time-of-flight analysis in milk samples from FR50 and control rat dams. Milk analysis of FR50 rats demonstrated that maternal undernutrition decreases lactose concentration and modulates lipid profile at postnatal day 10 by increasing the unsaturated fatty acids/saturated fatty acids and diminishes serotransferrin levels at postnatal day 21. Our data indicate that maternal perinatal undernutrition modifies milk composition both quantitatively and qualitatively. These modifications by maternal nutrition open new perspectives to identify molecules that could be used in artificial milk to protect from the subsequent development of metabolic diseases.

Exposure to bis(maltolato)oxovanadium(IV) increases levels of hepcidin mRNA and impairs the homeostasis of iron but not that of manganese

The aim of this study was to examine whether alterations in iron homeostasis, caused by exposure to vanadium, are related to changes in the gene expression of hepatic hepcidin. Two groups of rats were examined: control and vanadium-exposed. Vanadium, as bis(maltolato)oxovanadium(IV) was supplied in the drinking water. The experiment had a duration of five weeks. Iron and manganese were measured in excreta, serum and tissues. Leptin, ferritin, IL-1β, IL-6, TNF-α, red blood cells, haemoglobin and haematocrit were determined. Protein carbonyl group levels and hepcidin gene expression were determined in the liver. In the vanadium-exposed rats, iron absorption, serum iron and leptin and all haematological parameters decreased. Levels of IL-6, TNF-α and ferritin in serum and of iron in the liver, spleen and heart increased. In the liver, levels of protein carbonyl groups and hepcidin mRNA were also higher in the vanadium-exposed group. Exposure to vanadium did not modify manganese homeostasis. The results obtained from this study provide the first evidence that bis(maltolato)oxovanadium(IV) produces an increase in the gene expression of the hepcidin, possibly caused by an inflammatory process. Both factors could be the cause of alterations in Fe homeostasis and the appearance of anaemia. However, Mn homeostasis was not affected.

Investigating the role of transferrin in the distribution of iron, manganese, copper, and zinc

The essential role of transferrin in mammalian iron metabolism is firmly established. Integral to our understanding of transferrin, studies in hypotransferrinemic mice, a model of inherited transferrin deficiency, have demonstrated that transferrin is essential for iron delivery for erythropoiesis and in the regulation of expression of hepcidin, a hormone that inhibits macrophage and enterocyte iron efflux. Here we investigate a potential role for transferrin in the distribution of three other physiologic metals, manganese, copper, and zinc. We first assessed metal content in transferrin-rich fractions of wild-type mouse sera and demonstrate that although both iron and manganese cofractionated predominantly with transferrin, the absolute levels of manganese are several orders of magnitude lower than those of iron. We next measured metal content in multiple tissues in wild-type and hypotransferrinemic mice of various ages. Tissue metal imbalances were severe for iron and minimal to moderate for some metals in some tissues in hypotransferrinemic mice. Metal levels measured in a transferrin-replete yet hepcidin-deficient and iron-loaded mouse strain suggested that the observed imbalances in tissue copper, zinc, and manganese levels were not all specific to hypotransferrinemic mice or caused directly by transferrin deficiency. Overall, our results suggest that transferrin does not have a primary role in the distribution of manganese, copper, or zinc to tissues and that the abnormalities observed in tissue manganese levels are not attributable to a direct role for transferrin in manganese metabolism but rather are attributable to an indirect effect of transferrin deficiency on hepcidin expression and/or iron metabolism.

Systemic iron homeostasis

The iron hormone hepcidin and its receptor and cellular iron exporter ferroportin control the major fluxes of iron into blood plasma: intestinal iron absorption, the delivery of recycled iron from macrophages, and the release of stored iron from hepatocytes. Because iron losses are comparatively very small, iron absorption and its regulation by hepcidin and ferroportin determine total body iron content. Hepcidin is in turn feedback-regulated by plasma iron concentration and iron stores, and negatively regulated by the activity of erythrocyte precursors, the dominant consumers of iron. Hepcidin and ferroportin also play a role in host defense and inflammation, and hepcidin synthesis is induced by inflammatory signals including interleukin-6 and activin B. This review summarizes and discusses recent progress in molecular characterization of systemic iron homeostasis and its disorders, and identifies areas for further investigation.

The clinical significance of the mini-nutritional assessment and the scored patient-generated subjective global assessment in elderly patients with stroke

OBJECTIVE

To evaluate the clinical usefulness of the subjective assessments of nutritional status (Mini-Nutritional Assessment [MNA] and scored patient-generated subjective global assessment [PG-SGA]), compared with the objective (hematological, biochemical, and anthropometric) assessments, and to identify the correlation between the MNA and the scored PG-SGA in elderly patients with stroke.

METHODS

Thirty-five stroke patients, aged 60 to 89 years old, participated in our study. The MNA, the scored PG-SGA and objective factors were evaluated. The objective malnutrition state was defined based on laboratory outcomes. According to the MNA and the scored PG-SGA classifications, total patients were respectively divided into three groups; well-nourished (W), at risk of malnutrition (R), and malnourished (M), and into four groups; normally nourished (A), suspected or mildly malnourished (B), moderately malnourished (C), and severely malnourished (D).

RESULTS

Mean age and body mass index of subjects were 70.6 years and 22.2 kg/m(2), respectively. Twenty-six (74.3%) patients were identified to be at an objectively malnourished state. In MNA, 3 (8.6%) patients were classified as group W, 13 (37.1%) as R, and 19 (54.3%) as M. Total MNA scores and three categorization had mild correlation with objective grouping (r=0.383, r=0.350, p<0.05, respectively). Restructuring into two groups by combining group R and M made strong correlation (r=0.520, p<0.01). On the basis of scored PG-SGA, 6 (17.1%) patients were sorted as group A, 10 (28.6%) as B, 15 (42.9%) as C, and 4 (11.4%) as D, respectively. Total scores and the grouping into four indicated meaningful correlation with the objective distinction (r=-0.403, p<0.05, r=0.449, p<0.01, respectively). There was a significant correlation between the MNA scores and the PG-SGA scores (r=-0.651, p<0.01).

CONCLUSION

It is proposed that the MNA and the scored PG-SGA would be useful in screening malnourished elderly patients with stroke.

Manganese and the brain

Manganese (Mn) is an essential trace metal that is pivotal for normal cell function and metabolism. Its homeostasis is tightly regulated; however, the mechanisms of Mn homeostasis are poorly characterized. While a number of proteins such as the divalent metal transporter 1, the transferrin/transferrin receptor complex, the ZIP family metal transporters ZIP-8 and ZIP-14, the secretory pathway calcium ATPases SPCA1 and SPCA2, ATP13A2, and ferroportin have been suggested to play a role in Mn transport, the degree that each of them contributes to Mn homeostasis has still to be determined. The recent discovery of SLC30A10 as a crucial Mn transporter in humans has shed further light on our understanding of Mn transport across the cell. Although essential, Mn is toxic at high concentrations. Mn neurotoxicity has been attributed to impaired dopaminergic (DAergic), glutamatergic and GABAergic transmission, mitochondrial dysfunction, oxidative stress, and neuroinflammation. As a result of preferential accumulation of Mn in the DAergic cells of the basal ganglia, particularly the globus pallidus, Mn toxicity causes extrapyramidal motor dysfunction. Firstly described as "manganism" in miners during the nineteenth century, this movement disorder resembles Parkinson's disease characterized by hypokinesia and postural instability. To date, a variety of acquired causes of brain Mn accumulation can be distinguished from an autosomal recessively inherited disorder of Mn metabolism caused by mutations in the SLC30A10 gene. Both, acquired and inherited hypermanganesemia, lead to Mn deposition in the basal ganglia associated with pathognomonic magnetic resonance imaging appearances of hyperintense basal ganglia on T1-weighted images. Current treatment strategies for Mn toxicity combine chelation therapy to reduce the body Mn load and iron (Fe) supplementation to reduce Mn binding to proteins that interact with both Mn and Fe. This chapter summarizes our current understanding of Mn homeostasis and the mechanisms of Mn toxicity and highlights the clinical disorders associated with Mn neurotoxicity.