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Efficacy and Mechanism of Buxue Yimu Pills () on Gynecological Anemia: A Combination of Clinical and Network Pharmacology Study. Chin J Integr Med 2021; 28:1072-1080. [PMID: 34241801 DOI: 10.1007/s11655-021-3296-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2020] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To compare the clinical efficacy and safety of oral administration of Buxue Yimu Pills (BYP, ), ferrous sulfate (FS), and the combination of BYP and FS on gynecological anemia, and investigate the mechanisms using network pharmacology. METHODS A randomized, controlled, multi-center clinical trial was conducted. Totally 150 patients with hemoglobin of 70-110 g/L due to gynecological conditions were recruited and randomized (using the block randomization method) into Buxue Yimu Pills group (24 g/d), oral iron group (FS Tablets, 0.9 g/d), and combined treatment group (BYP, 24 g/d plus FS Tablets, 0.9 g/d), 50 patients in each group. At the enrollment and 4-week treatment, complete blood count, serum iron indexes were evaluated. Adverse events, liver and renal functions, as well as blood coagulation were observed. Network pharmacology was conducted to identify the active ingredients and explore the potential mechanisms of BYP. RESULTS Ten (20%) and 7 (14%) participants discontinued the therapy due to gastrointestinal symptoms in oral iron and combination treatment groups. All 3 groups showed elevated hemoglobin. The patients in the iron group exhibited typically elevated in serum iron and ferritin and decreased in total iron-binding capacity. No change in iron indexes was observed in BYP group. The patients in the combination treatment group neither showed significant changes in serum ferritin nor total iron-binding capacity. No significant adverse reactions were observed in the BYP group. The network pharmacology identified 27 bioactive compounds and 145 targets of BYP on gynecological anemia. Biological processes and pathways including regulation of inflammation, hormone, angiogenesis and hemostasis, response to decreased oxygen levels, effects on myeloma cell, and response to metal ions were identified. CONCLUSION BYP contributes to the practical improvement on gynecological anemia potentially through multi-target mechanisms and optimized iron re-distribution. (Trial registration: No. NCT03232554).
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Jones G, Goswami SK, Kang H, Choi HS, Kim J. Combating iron overload: a case for deferoxamine-based nanochelators. Nanomedicine (Lond) 2020; 15:1341-1356. [PMID: 32429801 PMCID: PMC7304435 DOI: 10.2217/nnm-2020-0038] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 03/16/2020] [Indexed: 12/11/2022] Open
Abstract
While iron is a nutrient metal, iron overload can result in multiple organ failures. Iron chelators, such as deferoxamine, are commonly used to ameliorate iron overload conditions. However, their uses are limited due to poor pharmacokinetics and adverse effects. Many novel chelator formulations have been developed to overcome these drawbacks. In this review, we have discussed various nanochelators, including linear and branched polymers, dendrimers, polyrotaxane, micelles, nanogels, polymeric nanoparticles and liposomes. Although these research efforts have mainly been focused on nanochelators with longer half-lives, prolonged residence of polymers in the body could raise potential safety issues. We also discussed recent advances in nanochelation technologies, including mechanism-based, long-acting nanochelators.
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Affiliation(s)
- Gregory Jones
- Department of Pharmaceutical Sciences, Bouve College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | - Sumanta Kumar Goswami
- Department of Pharmaceutical Sciences, Bouve College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | - Homan Kang
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, USA
| | - Hak Soo Choi
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, USA
| | - Jonghan Kim
- Department of Pharmaceutical Sciences, Bouve College of Health Sciences, Northeastern University, Boston, MA 02115, USA
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Han M, Chang J, Kim J. Loss of divalent metal transporter 1 function promotes brain copper accumulation and increases impulsivity. J Neurochem 2016; 138:918-28. [PMID: 27331785 DOI: 10.1111/jnc.13717] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 06/08/2016] [Accepted: 06/09/2016] [Indexed: 12/20/2022]
Abstract
The divalent metal transporter 1 (DMT1) is a major iron transporter required for iron absorption and erythropoiesis. Loss of DMT1 function results in microcytic anemia. While iron plays an important role in neural function, the behavioral consequences of DMT1 deficiency are largely unexplored. The goal of this study was to define the neurobehavioral and neurochemical phenotypes of homozygous Belgrade (b/b) rats that carry DMT1 mutation and explore potential mechanisms of these phenotypes. The b/b rats (11-12 weeks old) and their healthy littermate heterozygous (+/b) Belgrade rats were subject to elevated plus maze tasks. The b/b rats spent more time in open arms, entered open arms more frequently and traveled more distance in the maze than +/b controls, suggesting increased impulsivity. Impaired emotional behavior was associated with down-regulation of GABA in the hippocampus in b/b rats. Also, b/b rats showed increased GABAA receptor α1 and GABA transporter, indicating altered GABAergic function. Furthermore, metal analysis revealed that b/b rats have decreased total iron, but normal non-heme iron, in the brain. Interestingly, b/b rats exhibited unusually high copper levels in most brain regions, including striatum and hippocampus. Quantitative PCR analysis showed that both copper importer copper transporter 1 and exporter copper-transporting ATPase 1 were up-regulated in the hippocampus from b/b rats. Finally, b/b rats exhibited increased 8-isoprostane levels and decreased glutathione/glutathione disulfide ratio in the hippocampus, reflecting elevated oxidative stress. Combined, our results suggest that copper loading in DMT1 deficiency could induce oxidative stress and impair GABA metabolism, which promote impulsivity-like behavior. Iron-copper model: Mutations in the divalent metal transporter 1 (DMT1) decrease body iron status and up-regulate copper absorption, which leads to copper loading in the brain and consequently increases metal-induced oxidative stress. This event disrupts GABAergic neurotransmission and promotes impulsivity-like behavior. Our model provides better understanding of physiological risks associated with imbalanced metal metabolism in mental function and, more specifically, the interactions with GABA and redox control in the treatment of emotional disorders.
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Affiliation(s)
- Murui Han
- Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, USA
| | - JuOae Chang
- Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Jonghan Kim
- Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, USA.
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Menon AV, Chang J, Kim J. Mechanisms of divalent metal toxicity in affective disorders. Toxicology 2015; 339:58-72. [PMID: 26551072 DOI: 10.1016/j.tox.2015.11.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 10/19/2015] [Accepted: 11/03/2015] [Indexed: 01/01/2023]
Abstract
Metals are required for proper brain development and play an important role in a number of neurobiological functions. The divalent metal transporter 1 (DMT1) is a major metal transporter involved in the absorption and metabolism of several essential metals like iron and manganese. However, non-essential divalent metals are also transported through this transporter. Therefore, altered expression of DMT1 can modify the absorption of toxic metals and metal-induced toxicity. An accumulating body of evidence has suggested that increased metal stores in the brain are associated with elevated oxidative stress promoted by the ability of metals to catalyze redox reactions, resulting in abnormal neurobehavioral function and the progression of neurodegenerative diseases. Metal overload has also been implicated in impaired emotional behavior, although the underlying mechanisms are not well understood with limited information. The current review focuses on psychiatric dysfunction associated with imbalanced metabolism of metals that are transported by DMT1. The investigations with respect to the toxic effects of metal overload on behavior and their underlying mechanisms of toxicity could provide several new therapeutic targets to treat metal-associated affective disorders.
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Affiliation(s)
| | - JuOae Chang
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
| | - Jonghan Kim
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA.
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Shawki A, Anthony SR, Nose Y, Engevik MA, Niespodzany EJ, Barrientos T, Öhrvik H, Worrell RT, Thiele DJ, Mackenzie B. Intestinal DMT1 is critical for iron absorption in the mouse but is not required for the absorption of copper or manganese. Am J Physiol Gastrointest Liver Physiol 2015; 309:G635-47. [PMID: 26294671 PMCID: PMC4609933 DOI: 10.1152/ajpgi.00160.2015] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 08/18/2015] [Indexed: 01/31/2023]
Abstract
Divalent metal-ion transporter-1 (DMT1) is a widely expressed iron-preferring membrane-transport protein that serves a critical role in erythroid iron utilization. We have investigated its role in intestinal metal absorption by studying a mouse model lacking intestinal DMT1 (i.e., DMT1(int/int)). DMT1(int/int) mice exhibited a profound hypochromic-microcytic anemia, splenomegaly, and cardiomegaly. That the anemia was due to iron deficiency was demonstrated by the following observations in DMT1(int/int) mice: 1) blood iron and tissue nonheme-iron stores were depleted; 2) mRNA expression of liver hepcidin (Hamp1) was depressed; and 3) intraperitoneal iron injection corrected the anemia, and reversed the changes in blood iron, nonheme-iron stores, and hepcidin expression levels. We observed decreased total iron content in multiple tissues from DMT1(int/int) mice compared with DMT1(+/+) mice but no meaningful change in copper, manganese, or zinc. DMT1(int/int) mice absorbed (64)Cu and (54)Mn from an intragastric dose to the same extent as did DMT1(+/+) mice but the absorption of (59)Fe was virtually abolished in DMT1(int/int) mice. This study reveals a critical function for DMT1 in intestinal nonheme-iron absorption for normal growth and development. Further, this work demonstrates that intestinal DMT1 is not required for the intestinal transport of copper, manganese, or zinc.
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Affiliation(s)
- Ali Shawki
- 1Department of Molecular & Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio; ,2Systems Biology & Physiology Program, University of Cincinnati College of Medicine, Cincinnati, Ohio;
| | - Sarah R. Anthony
- 1Department of Molecular & Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio;
| | - Yasuhiro Nose
- 3Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, North Carolina;
| | - Melinda A. Engevik
- 1Department of Molecular & Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio; ,2Systems Biology & Physiology Program, University of Cincinnati College of Medicine, Cincinnati, Ohio;
| | - Eric J. Niespodzany
- 1Department of Molecular & Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio;
| | - Tomasa Barrientos
- 3Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, North Carolina;
| | - Helena Öhrvik
- 3Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, North Carolina; ,4Department of Medical Biochemistry & Microbiology, Uppsala University, Uppsala, Sweden; and
| | - Roger T. Worrell
- 1Department of Molecular & Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio; ,2Systems Biology & Physiology Program, University of Cincinnati College of Medicine, Cincinnati, Ohio;
| | - Dennis J. Thiele
- 3Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, North Carolina; ,5Department of Biochemistry, Duke University Medical Center, Durham, North Carolina
| | - Bryan Mackenzie
- Department of Molecular & Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio; Systems Biology & Physiology Program, University of Cincinnati College of Medicine, Cincinnati, Ohio;
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Skjørringe T, Burkhart A, Johnsen KB, Moos T. Divalent metal transporter 1 (DMT1) in the brain: implications for a role in iron transport at the blood-brain barrier, and neuronal and glial pathology. Front Mol Neurosci 2015; 8:19. [PMID: 26106291 PMCID: PMC4458610 DOI: 10.3389/fnmol.2015.00019] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 05/20/2015] [Indexed: 01/25/2023] Open
Abstract
Iron is required in a variety of essential processes in the body. In this review, we focus on iron transport in the brain and the role of the divalent metal transporter 1 (DMT1) vital for iron uptake in most cells. DMT1 locates to cellular membranes and endosomal membranes, where it is a key player in non-transferrin bound iron uptake and transferrin-bound iron uptake, respectively. Four isoforms of DMT1 exist, and their respective characteristics involve a complex cell-specific regulatory machinery all controlling iron transport across these membranes. This complexity reflects the fine balance required in iron homeostasis, as this metal is indispensable in many cell functions but highly toxic when appearing in excess. DMT1 expression in the brain is prominent in neurons. Of serious dispute is the expression of DMT1 in non-neuronal cells. Recent studies imply that DMT1 does exist in endosomes of brain capillary endothelial cells denoting the blood-brain barrier. This supports existing evidence that iron uptake at the BBB occurs by means of transferrin-receptor mediated endocytosis followed by detachment of iron from transferrin inside the acidic compartment of the endosome and DMT1-mediated pumping iron into the cytosol. The subsequent iron transport across the abluminal membrane into the brain likely occurs by ferroportin. The virtual absent expression of transferrin receptors and DMT1 in glial cells, i.e., astrocytes, microglia and oligodendrocytes, suggest that the steady state uptake of iron in glia is much lower than in neurons and/or other mechanisms for iron uptake in these cell types prevail.
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Affiliation(s)
- Tina Skjørringe
- Section of Neurobiology, Biomedicine, Institute of Medicine and Health Technology, Aalborg University Aalborg, Denmark
| | - Annette Burkhart
- Section of Neurobiology, Biomedicine, Institute of Medicine and Health Technology, Aalborg University Aalborg, Denmark
| | - Kasper Bendix Johnsen
- Section of Neurobiology, Biomedicine, Institute of Medicine and Health Technology, Aalborg University Aalborg, Denmark
| | - Torben Moos
- Section of Neurobiology, Biomedicine, Institute of Medicine and Health Technology, Aalborg University Aalborg, Denmark
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Zhang WL, Meng HZ, Yang MW. Regulation of DMT1 on Bone Microstructure in Type 2 Diabetes. Int J Med Sci 2015; 12:441-9. [PMID: 26078704 PMCID: PMC4466406 DOI: 10.7150/ijms.11986] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/18/2015] [Indexed: 12/26/2022] Open
Abstract
Diabetic osteoporosis is gradually attracted people's attention. However, the process of bone microstructure changes in diabetic patients, and the exact mechanism of osteoblast iron overload are unclear. Therefore, the present study aimed to explore the function of DMT1 in the pathological process of diabetic osteoporosis. We build the type two diabetes osteoporosis models with SD rats and Belgrade rats, respectively. Difference expression of DMT1 was detected by using the method of immunohistochemistry and western blotting. Detection of bone microstructure and biomechanics and iron content for each group of samples. We found that DMT1 expression in type 2 diabetic rats was higher than that in normal rats. The bone biomechanical indices and bone microstructure in the rat model deficient in DMT1 was significantly better than that in the normal diabetic model. The loss of DMT1 can reduce the content of iron in bone. These findings indicate that DMT1 expression was enhanced in the bone tissue of type 2 diabetic rats, and plays an important role in the pathological process of diabetic osteoporosis. Moreover, DMT1 may be a potential therapeutic target for diabetic osteoporosis.
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Affiliation(s)
- Wei-Lin Zhang
- Department of Orthopedics, the First Hospital of China Medical University, Shenyang, Liaoning, China
| | - Hong-Zheng Meng
- Department of Orthopedics, the First Hospital of China Medical University, Shenyang, Liaoning, China
| | - Mao-Wei Yang
- Department of Orthopedics, the First Hospital of China Medical University, Shenyang, Liaoning, China
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Veuthey T, Wessling-Resnick M. Pathophysiology of the Belgrade rat. Front Pharmacol 2014; 5:82. [PMID: 24795636 PMCID: PMC4000996 DOI: 10.3389/fphar.2014.00082] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 04/02/2014] [Indexed: 01/01/2023] Open
Abstract
The Belgrade rat is an animal model of divalent metal transporter 1 (DMT1) deficiency. This strain originates from an X-irradiation experiment first reported in 1966. Since then, the Belgrade rat’s pathophysiology has helped to reveal the importance of iron balance and the role of DMT1. This review discusses our current understanding of iron transport homeostasis and summarizes molecular details of DMT1 function. We describe how studies of the Belgrade rat have revealed key roles for DMT1 in iron distribution to red blood cells as well as duodenal iron absorption. The Belgrade rat’s pathology has extended our knowledge of hepatic iron handling, pulmonary and olfactory iron transport as well as brain iron uptake and renal iron handling. For example, relationships between iron and manganese metabolism have been discerned since both are essential metals transported by DMT1. Pathophysiologic features of the Belgrade rat provide us with a unique and interesting animal model to understand iron homeostasis.
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Affiliation(s)
- Tania Veuthey
- Department of Genetics and Complex Diseases, Harvard School of Public Health Boston, MA, USA
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9
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Abstract
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.
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Veuthey T, Hoffmann D, Vaidya VS, Wessling-Resnick M. Impaired renal function and development in Belgrade rats. Am J Physiol Renal Physiol 2013; 306:F333-43. [PMID: 24226520 DOI: 10.1152/ajprenal.00285.2013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Belgrade rats carry a disabling mutation in the iron transporter divalent metal transporter 1 (DMT1). Although DMT1 plays a major role in intestinal iron absorption, the transporter is also highly expressed in the kidney, where its function remains unknown. The goal of this study was to characterize renal physiology of Belgrade rats. Male Belgrade rats died prematurely with ∼50% survival at 20 wk of age. Necropsy results indicated marked glomerular nephritis and chronic end-stage renal disease. By 15 wk of age, Belgrade rats displayed altered renal morphology associated with sclerosis and fibrosis. Creatinine clearance was significantly lower compared with heterozygote littermates. Urinary biomarkers of kidney injury, including albumin, fibrinogen, and kidney injury molecule-1, were significantly elevated. Pilot morphological studies suggest that nephrogenesis is delayed in Belgrade rat pups due to their low iron status and fetal growth restriction. Such defects in renal development most likely underlie the compromised renal metabolism observed in adult b/b rats. Belgrade rat kidney nonheme iron levels were not different from controls but urinary iron and transferrin levels were higher. These results further implicate an important role for the transporter in kidney function not only in iron reabsorption but also in glomerular filtration of the serum protein.
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Affiliation(s)
- Tania Veuthey
- Dept. of Genetics & Complex Diseases, Harvard School of Public Health, 665 Huntington Ave., Boston, MA 02115.
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Jia X, Kim J, Veuthey T, Lee CH, Wessling-Resnick M. Glucose metabolism in the Belgrade rat, a model of iron-loading anemia. Am J Physiol Gastrointest Liver Physiol 2013; 304:G1095-102. [PMID: 23599042 PMCID: PMC3680718 DOI: 10.1152/ajpgi.00453.2012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The iron-diabetes hypothesis proposes an association between iron overload and glucose metabolism that is supported by a number of epidemiological studies. The prevalence of type 2 diabetes in patients with hereditary hemochromatosis and iron-loading thalassemia supports this hypothesis. The Belgrade rat carries a mutation in the iron transporter divalent metal transporter 1 (DMT1) resulting in iron-loading anemia. In this study, we characterized the glycometabolic status of the Belgrade rat. Belgrade rats displayed normal glycemic control. Insulin signaling and secretion were not impaired, and pancreatic tissue did not incur damage despite high levels of nonheme iron. These findings suggest that loss of DMT1 protects against oxidative damage to the pancreas and helps to maintain insulin sensitivity despite iron overload. Belgrade rats had lower body weight but increased food consumption compared with heterozygous littermates. The unexpected energy balance was associated with increased urinary glucose output. Increased urinary excretion of electrolytes, including iron, was also observed. Histopathological evidence suggests that altered renal function is secondary to changes in kidney morphology, including glomerulosclerosis. Thus, loss of DMT1 appears to protect the pancreas from injury but damages the integrity of kidney structure and function.
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Affiliation(s)
- Xuming Jia
- Department of Genetics & Complex Diseases, Harvard School of Public Health, Boston, Massachusetts
| | - Jonghan Kim
- Department of Genetics & Complex Diseases, Harvard School of Public Health, Boston, Massachusetts
| | - Tania Veuthey
- Department of Genetics & Complex Diseases, Harvard School of Public Health, Boston, Massachusetts
| | - Chih-Hao Lee
- Department of Genetics & Complex Diseases, Harvard School of Public Health, Boston, Massachusetts
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Kim J, Jia X, Buckett PD, Liu S, Lee CH, Wessling-Resnick M. Iron loading impairs lipoprotein lipase activity and promotes hypertriglyceridemia. FASEB J 2012; 27:1657-63. [PMID: 23241313 DOI: 10.1096/fj.12-224386] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Iron loading is associated with altered lipid metabolism, but underlying mechanisms remain unknown. We compared serum iron and triglycerides (TGs) in Belgrade rats, a genetic model of iron-loading anemia. Homozygous b/b rats had greater serum iron (68 vs. 28 μM; P=0.0004) and TG levels (180 vs. 84 mg/dl; P=0.014) compared to +/b controls. To confirm the association between iron loading and high TGs, Fischer rats were fed chow containing 1% carbonyl iron. Compared to controls pair-fed normal chow, carbonyl iron-fed rats had elevated serum iron (42 vs. 21 μM; P=0.007) and TGs (190 vs. 115 mg/dl; P=0.009). Despite normal hepatic production and secretion, TG clearance was lower in b/b than +/b rats due to reduced serum lipoprotein lipase (LPL) activity (3.1 vs. 5.0 mM/min; P=0.026). Likewise, LPL was lower in carbonyl iron-fed rats compared to controls (2.4 vs. 3.7 mM/min; P=0.017). Direct addition of iron to serum ex vivo or recombinant LPL in vitro decreased enzymatic activity in a dose-dependent manner. Lowering serum iron in Belgrade rats reduced TG levels (274 to 67 mg/dl, P=0.001). This study explains the relationship between iron status and lipid metabolism and provides mechanistic support for interventions that reduce serum iron levels in individuals at risk for hypertriglyceridemia.
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Affiliation(s)
- Jonghan Kim
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, Massachusetts 02115, USA
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Paragas N, Qiu A, Hollmen M, Nickolas TL, Devarajan P, Barasch J. NGAL-Siderocalin in kidney disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:1451-8. [PMID: 22728330 DOI: 10.1016/j.bbamcr.2012.06.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 06/06/2012] [Accepted: 06/13/2012] [Indexed: 12/11/2022]
Abstract
Kidney damage induces the expression of a myriad of proteins in the serum and in the urine. The function of these proteins in the sequence of damage and repair is now being studied in genetic models and by novel imaging techniques. One of the most intensely expressed proteins is lipocalin2, also called NGAL or Siderocalin. While this protein has been best studied by clinical scientists, only a few labs study its underlying metabolism and function in tissue damage. Structure-function studies, imaging studies and clinical studies have revealed that NGAL-Siderocalin is an endogenous antimicrobial with iron scavenging activity. This review discusses the "iron problem" of kidney damage, the tight linkage between kidney damage and NGAL-Siderocalin expression and the potential roles that NGAL-Siderocalin may serve in the defense of the urogenital system. This article is part of a Special Issue entitled: Cell Biology of Metals.
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Affiliation(s)
- Neal Paragas
- College of Physicians & Surgeons of Columbia University, New York, NY, USA
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Horvathova M, Kapralova K, Zidova Z, Dolezal D, Pospisilova D, Divoky V. Erythropoietin-driven signaling ameliorates the survival defect of DMT1-mutant erythroid progenitors and erythroblasts. Haematologica 2012; 97:1480-8. [PMID: 22580996 DOI: 10.3324/haematol.2011.059550] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Hypochromic microcytic anemia associated with ineffective erythropoiesis caused by recessive mutations in divalent metal transporter 1 (DMT1) can be improved with high-dose erythropoietin supplementation. The aim of this study was to characterize and compare erythropoiesis in samples from a DMT1-mutant patient before and after treatment with erythropoietin, as well as in a mouse model with a DMT1 mutation, the mk/mk mice. DESIGN AND METHODS Colony assays were used to compare the in vitro growth of pre-treatment and post-treatment erythroid progenitors in a DMT1-mutant patient. To enable a comparison with human data, high doses of erythropoietin were administered to mk/mk mice. The apoptotic status of erythroblasts, the expression of anti-apoptotic proteins, and the key components of the bone marrow-hepcidin axis were evaluated. RESULTS Erythropoietin therapy in vivo or the addition of a broad-spectrum caspase inhibitor in vitro significantly improved the growth of human DMT1-mutant erythroid progenitors. A decreased number of apoptotic erythroblasts was detected in the patient's bone marrow after erythropoietin treatment. In mk/mk mice, erythropoietin administration increased activation of signal transducer and activator of transcription 5 (STAT5) and reduced apoptosis in bone marrow and spleen erythroblasts. mk/mk mice propagated on the 129S6/SvEvTac background resembled DMT1-mutant patients in having increased plasma iron but differed by having functional iron deficiency after erythropoietin administration. Co-regulation of hepcidin and growth differentiation factor 15 (GDF15) levels was observed in mk/mk mice but not in the patient. CONCLUSIONS Erythropoietin inhibits apoptosis of DMT1-mutant erythroid progenitors and differentiating erythroblasts. Ineffective erythropoiesis associated with defective erythroid iron utilization due to DMT1 mutations has specific biological and clinical features.
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Affiliation(s)
- Monika Horvathova
- Department of Biology, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic
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Ruvin Kumara VM, Wessling-Resnick M. Olfactory ferric and ferrous iron absorption in iron-deficient rats. Am J Physiol Lung Cell Mol Physiol 2012; 302:L1280-6. [PMID: 22492739 DOI: 10.1152/ajplung.00004.2012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The absorption of metals from the nasal cavity to the blood and the brain initiates an important route of occupational exposures leading to health risks. Divalent metal transporter-1 (DMT1) plays a significant role in the absorption of intranasally instilled manganese, but whether iron uptake would be mediated by the same pathway is unknown. In iron-deficient rats, blood (59)Fe levels after intranasal administration of the radioisotope in the ferrous form were significantly higher than those observed for iron-sufficient control rats. Similar results were obtained when ferric iron was instilled intranasally, and blood levels of (59)Fe were even greater in the iron-deficient rats compared with the amount of ferrous iron absorbed. Experiments with Belgrade (b/b) rats showed that DMT1 deficiency limited ferric iron uptake from the nasal cavity to the blood compared with +/b controls matched for iron deficiency. These results indicate that olfactory uptake of ferric iron by iron-deficient rats involves DMT1. Western blot experiments confirmed that DMT1 levels are significantly higher in iron-deficient rats compared with iron-sufficient controls in olfactory tissue. Thus the molecular mechanism of olfactory iron absorption is regulated by body iron status and involves DMT1.
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Affiliation(s)
- V M Ruvin Kumara
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, MA 02115, USA
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Shawki A, Knight PB, Maliken BD, Niespodzany EJ, Mackenzie B. H(+)-coupled divalent metal-ion transporter-1: functional properties, physiological roles and therapeutics. CURRENT TOPICS IN MEMBRANES 2012. [PMID: 23177986 DOI: 10.1016/b978-0-12-394316-3.00005-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Divalent metal-ion transporter-1 (DMT1) is a widely expressed, iron-preferring membrane transport protein. Animal models establish that DMT1 plays indispensable roles in intestinal nonheme-iron absorption and iron acquisition by erythroid precursor cells. Rare mutations in human DMT1 result in severe microcytic-hypochromic anemia. When we express DMT1 in RNA-injected Xenopus oocytes, we observe rheogenic Fe(2+) transport that is driven by the proton electrochemical potential gradient. In that same preparation, DMT1 also transports cadmium and manganese but not copper. Whether manganese metabolism relies upon DMT1 remains unclear but DMT1 contributes to the effects of overexposure to cadmium and manganese in some tissues. There exist at least four DMT1 isoforms that arise from variant transcription of the SLC11A2 gene. Whereas these isoforms display identical functional properties, N- and C-terminal variations contain cues that direct the cell-specific targeting of DMT1 isoforms to discrete subcellular compartments (plasma membrane, endosomes, and lysosomes). An iron-responsive element (IRE) in the mRNA 3'-untranslated region permits the regulation of some isoforms by iron status, and additional mechanisms by which DMT1 is regulated are emerging. Natural-resistance-associated macrophage protein-1 (NRAMP1)-the only other member of the mammalian SLC11 gene family-contributes to antimicrobial function by extruding from the phagolysosome divalent metal ions (e.g. Mn(2+)) that may be essential cofactors for bacteria-derived enzymes or required for bacterial growth. The principal or only intestinal nonheme-iron transporter, DMT1 is a validated therapeutic target in hereditary hemochromatosis (HHC) and other iron-overload disorders.
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Affiliation(s)
- Ali Shawki
- Department of Molecular & Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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A novel N491S mutation in the human SLC11A2 gene impairs protein trafficking and in association with the G212V mutation leads to microcytic anemia and liver iron overload. Blood Cells Mol Dis 2011; 47:243-8. [PMID: 21871825 DOI: 10.1016/j.bcmd.2011.07.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 07/01/2011] [Accepted: 07/12/2011] [Indexed: 11/21/2022]
Abstract
BACKGROUND DMT1 is a transmembrane iron transporter involved in iron duodenal absorption and cellular iron uptake. Mutations in the human SLC11A2 gene coding DMT1 lead to microcytic anemia and hepatic iron overload, with unexpectedly low levels of plasma ferritin in the presence of iron stores. DESIGN AND METHODS We report a patient with a similar phenotype due to two mutations in the SLC11A2 gene, the known p.Gly212Val (G212V) mutation and a novel one, p.Asn491Ser (N491S). To assess the expression of DMT1 in human liver, we studied the expression of the four DMT1 mRNA isoforms by real-time quantitative PCR in control human liver samples. We also studied the effect of G212V and N491S DMT1 mutations on RNA splicing in blood leukocytes and cellular trafficking of dsRed2-tagged-DMT1 protein in the human hepatic cell line HuH7. RESULTS Our results showed that i) only the isoforms 1B-IRE and 1B-nonIRE were significantly expressed in human liver; ii) the G212V mutation did not seem to affect mRNA splicing and the N491S mutation induced a splicing alteration leading to a truncated protein, which seemed quantitatively of low relevance; and iii) the N491S mutation, in contrast to the G212V mutation, led to abnormal protein trafficking. CONCLUSIONS Our data confirm the major role of DMT1 in the maintenance of iron homeostasis in humans and demonstrate that the N491S mutation, through its deleterious effect on protein trafficking, contributes together with the G212V mutation to the development of anemia and hepatic iron overload.
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Kim J, Molina RM, Donaghey TC, Buckett PD, Brain JD, Wessling-Resnick M. Influence of DMT1 and iron status on inflammatory responses in the lung. Am J Physiol Lung Cell Mol Physiol 2011; 300:L659-65. [PMID: 21278260 DOI: 10.1152/ajplung.00343.2010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Divalent metal transporter 1 (DMT1) is the major iron transporter responsible for duodenal dietary iron absorption and is required for erythropoiesis. Recent studies suggest that loss of DMT1 activity could be involved in metal-related lung injury, but little is known about the effects of iron status and DMT1 function on pulmonary inflammation. To better define the role of DMT1 and iron status in pulmonary inflammatory responses, we performed bronchoalveolar lavage (BAL) following intratracheal instillation of lipopolysaccharide (LPS) to the Belgrade rat, an animal model deficient in DMT1 function. In the basal state, the BAL fluid of Belgrade rats had more macrophages and higher lactate dehydrogenase, myeloperoxidase, albumin, and hemoglobin levels compared with heterozygote control rats. Following LPS instillation, the macrophage fraction relative to total BAL cell content and levels of albumin and IgM were increased in Belgrade rats compared with controls. In contrast, heterozygote Belgrade rats made anemic by diet-induced iron deficiency exhibited attenuated inflammatory responses to LPS. These combined results show that pulmonary inflammation can be modified by both DMT1 and iron status. Loss of DMT1 alters pulmonary responses necessary for lung homeostasis in the basal state and enhances LPS-induced inflammation and therefore would contribute to progression of lung injury.
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Affiliation(s)
- Jonghan Kim
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, Massachusetts, USA
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Garrick MD, Garrick LM. Cellular iron transport. Biochim Biophys Acta Gen Subj 2009; 1790:309-25. [DOI: 10.1016/j.bbagen.2009.03.018] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 03/23/2009] [Accepted: 03/23/2009] [Indexed: 01/24/2023]
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Suzuki T, Momoi K, Hosoyamada M, Kimura M, Shibasaki T. Normal cadmium uptake in microcytic anemia mk/mk mice suggests that DMT1 is not the only cadmium transporter in vivo. Toxicol Appl Pharmacol 2008; 227:462-7. [DOI: 10.1016/j.taap.2007.10.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Revised: 10/17/2007] [Accepted: 10/23/2007] [Indexed: 11/28/2022]
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Thompson K, Molina RM, Donaghey T, Brain JD, Wessling-Resnick M. Iron absorption by Belgrade rat pups during lactation. Am J Physiol Gastrointest Liver Physiol 2007; 293:G640-4. [PMID: 17640977 DOI: 10.1152/ajpgi.00153.2007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Divalent metal transporter-1 (DMT1) mediates dietary nonheme iron absorption. Belgrade (b) rats have defective iron metabolism due to a mutation in the DMT1 gene. To examine the role of DMT1 in neonatal iron assimilation, b/b and b/+ pups were cross-fostered to F344 Fischer dams injected with (59)FeCl(3) twice weekly during lactation. Tissue distribution of the radioisotope in the pups was determined at weaning (day 21). The b/b pups had blood (59)Fe levels significantly lower than b/+ controls but significantly higher (59)Fe tissue levels in heart, bone marrow, skeletal muscle, kidney, liver, spleen, stomach, and intestines. To study the pharmacokinetics of nonheme iron absorption at the time of weaning, (59)FeCl(3) was administered to 21-day-old b/b and b/+ rats by intragastric gavage. Blood (59)Fe levels measured 5 min to 4 h postgavage were significantly lower in b/b rats, consistent with impaired DMT1 function in intestinal iron absorption. Tissue (59)Fe levels were also lower in b/b rats postgavage. Combined, these data suggest that DMT1 function is not essential for iron assimilation from milk during early development in the rat.
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Affiliation(s)
- Khristy Thompson
- Department of Genetics and Complex Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
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