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Transferrin receptor 1 controls systemic iron homeostasis by fine-tuning hepcidin expression to hepatocellular iron load. Blood 2018; 133:344-355. [PMID: 30538134 DOI: 10.1182/blood-2018-05-850404] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 12/04/2018] [Indexed: 02/06/2023] Open
Abstract
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 TfrcAlb-Cre mice bearing hepatocyte-specific ablation of Tfr1 to explore implications in hepatocellular and systemic iron homeostasis. TfrcAlb-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 Tfrcfl/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 TfrcAlb-Cre and Tfrcfl/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 TfrcAlb-Cre mice to iron-deficiency anemia. TfrcAlb-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 TfrcAlb-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.
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Jiang S, Yan K, Sun B, Gao S, Yang X, Ni Y, Ma W, Zhao R. Long-Term High-Fat Diet Decreases Hepatic Iron Storage Associated with Suppressing TFR2 and ZIP14 Expression in Rats. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:11612-11621. [PMID: 30350980 DOI: 10.1021/acs.jafc.8b02974] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
High-fat diet-induced obesity is known to disturb hepatic iron metabolism in a time-dependent manner. The mechanism of decreased hepatic iron deposits induced by long-term high-fat diet needs to be further investigated. In this study, 24 6-week-old male Sprague-Dawley rats were given a 16-week high-fat diet and hepatic iron metabolism was examined. High-fat diet feeding considerably decreased hepatic iron contents, enhanced transferrin expression, and reduced the expression of ferritin heavy chain, ferritin light chain, and hepatic iron uptake-related proteins (transferrin receptor 2, TFR2, and ZRT/IRT-like protein 14, ZIP14) in rats. Impaired expression of hepatic TFR2 coincided with DNA hypermethylation on the promoter and repressed expression of transcription factor hepatocyte nuclear factor 4α (HNF4α). miR-181 family expression was markedly increased and verified to regulate Zip14 expression by the dual-luciferase reporter system. Taken together, long-term high-fat diet decreases hepatic iron storage, which is closely linked to inhibition of liver iron transport through the TFR2 and ZIP14-dependent pathway.
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Affiliation(s)
- Shuxia Jiang
- Key Laboratory of Animal Physiology and Biochemistry, College of Veterinary Medicine , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , People's Republic of China
| | - Kai Yan
- Key Laboratory of Animal Physiology and Biochemistry, College of Veterinary Medicine , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , People's Republic of China
| | - Bo Sun
- Key Laboratory of Animal Physiology and Biochemistry, College of Veterinary Medicine , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , People's Republic of China
| | - Shixing Gao
- Key Laboratory of Animal Physiology and Biochemistry, College of Veterinary Medicine , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , People's Republic of China
| | - Xiaojing Yang
- MOE Joint International Research Laboratory of Animal Health & Food Safety , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , People's Republic of China
- Key Laboratory of Animal Physiology and Biochemistry, College of Veterinary Medicine , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , People's Republic of China
| | - Yingdong Ni
- MOE Joint International Research Laboratory of Animal Health & Food Safety , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , People's Republic of China
- Key Laboratory of Animal Physiology and Biochemistry, College of Veterinary Medicine , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , People's Republic of China
| | - Wenqiang Ma
- MOE Joint International Research Laboratory of Animal Health & Food Safety , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , People's Republic of China
- Key Laboratory of Animal Physiology and Biochemistry, College of Veterinary Medicine , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , People's Republic of China
| | - Ruqian Zhao
- MOE Joint International Research Laboratory of Animal Health & Food Safety , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , People's Republic of China
- Key Laboratory of Animal Physiology and Biochemistry, College of Veterinary Medicine , Nanjing Agricultural University , Nanjing , Jiangsu 210095 , People's Republic of China
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Gartmann L, Wex T, Grüngreiff K, Reinhold D, Kalinski T, Malfertheiner P, Schütte K. Expression of zinc transporters ZIP4, ZIP14 and ZnT9 in hepatic carcinogenesis-An immunohistochemical study. J Trace Elem Med Biol 2018; 49:35-42. [PMID: 29895370 DOI: 10.1016/j.jtemb.2018.04.034] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 04/25/2018] [Accepted: 04/26/2018] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Dysregulation of both, systemic zinc levels and tissue-specific zinc transporters, is reported in chronic inflammatory and malignant liver disease (hepatocellular carcinoma, HCC). Aim of this study is to assess the expression level of three zinc transporters in liver tissue and HCC: ZIP4, ZIP14 and ZnT9. METHODS The study is based on tissue samples obtained from 138 patients with histologically proven HCC. Tissue specimens from tumor (n = 138) and extra-lesional specimens (n = 72) were assessed immunohistochemically for the expression of the three zinc transporters. Expression levels were semi-quantitatively scored and statistically analyzed with respect to the etiology of HCC (alcohol, AFLD; non-alcoholic fatty liver disease, NAFLD; virus-hepatitis, VH) and survival. RESULTS Overall, expression levels of ZIP4, ZIP14 and ZnT9 were significantly higher in HCC tissue than in adjacent extra-lesional liver tissue. Expression levels in tumor tissue and survival time revealed a negative correlation for ZIP4 and ZIP14, and in part for ZnT9 (nuclear staining) (p < 0.05), whereas cytoplasmic staining of ZnT9 did not correlate with survival. Furthermore, the expression level of ZIP4 in extra-lesional tissue showed inverse correlation with survival time. CONCLUSION The upregulation of zinc transporters in hepatic carcinogenesis and its negative correlation with survival time implies a regulatory/functional link between zinc-homeostasis and development/progression of HCC that deserves to be further explored.
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Affiliation(s)
- Laura Gartmann
- Department of Gastroenterology, Hepatology and Infectious Diseases, Otto-von-Guericke University, Leipziger Str. 44, D-39120 Magdeburg, Germany; Medical Laboratory for Clinical Chemistry, Microbiology and Infectious Diseases "Prof. Schenk/Dr. Ansorge & Colleagues", Department Molecular Genetics, Schwiesaustr. 11, D-39124, Magdeburg, Germany
| | - Thomas Wex
- Department of Gastroenterology, Hepatology and Infectious Diseases, Otto-von-Guericke University, Leipziger Str. 44, D-39120 Magdeburg, Germany; Medical Laboratory for Clinical Chemistry, Microbiology and Infectious Diseases "Prof. Schenk/Dr. Ansorge & Colleagues", Department Molecular Genetics, Schwiesaustr. 11, D-39124, Magdeburg, Germany
| | - Kurt Grüngreiff
- Clinic of Gastroenterology, City Hospital Magdeburg, Klinikum Magdeburg GmbH, Birkenallee 34, D-39130, Magdeburg, Germany
| | - Dirk Reinhold
- Institute of Molecular and Clinical Immunology, Otto-von-Guericke University, Leipziger Str. 44, D-39120 Magdeburg, Germany
| | - Thomas Kalinski
- Institute of Pathology, Otto-von-Guericke University, Leipziger Str. 44, D-39120, Magdeburg, Germany
| | - Peter Malfertheiner
- Department of Gastroenterology, Hepatology and Infectious Diseases, Otto-von-Guericke University, Leipziger Str. 44, D-39120 Magdeburg, Germany
| | - Kerstin Schütte
- Department of Gastroenterology, Hepatology and Infectious Diseases, Otto-von-Guericke University, Leipziger Str. 44, D-39120 Magdeburg, Germany; Department of Internal Medicine and Gastroenterology, Niels-Stensen-Kliniken, Marienhospital Osnabrück GmbH, Bischofsstraße 1, D-49074, Osnabrück, Germany.
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54
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How cellular Zn 2+ signaling drives physiological functions. Cell Calcium 2018; 75:53-63. [PMID: 30145429 DOI: 10.1016/j.ceca.2018.08.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/16/2018] [Accepted: 08/17/2018] [Indexed: 01/10/2023]
Abstract
Zinc is an essential micronutrient affecting many aspects of human health. Cellular Zn2+ homeostasis is critical for cell function and survival. Zn2+, acting as a first or second messenger, triggers signaling pathways that mediate the physiological roles of Zn2+. Transient changes in Zn2+ concentrations within the cell or in the extracellular region occur following its release from Zn2+ binding metallothioneins, its transport across membranes by the ZnT or ZIP transporters, or release of vesicular Zn2+. These transients activate a distinct Zn2+ sensing receptor, ZnR/GPR39, or modulate numerous proteins and signaling pathways. Importantly, Zn2+ signaling regulates cellular physiological functions such as: proliferation, differentiation, ion transport and secretion. Indeed, novel therapeutic approaches aimed to maintain Zn2+ homeostasis and signaling are evolving. This review focuses on recent findings describing roles of Zn2+ and its transporters in regulating physiological or pathological processes.
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Bowers K, Srai SKS. The trafficking of metal ion transporters of the Zrt- and Irt-like protein family. Traffic 2018; 19:813-822. [PMID: 29952128 DOI: 10.1111/tra.12602] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 06/25/2018] [Accepted: 06/25/2018] [Indexed: 12/28/2022]
Abstract
Metal ion transporters of the Zrt- and Irt-like protein (ZIP, or SLC39A) family transport zinc, iron, manganese and/or cadmium across cellular membranes and into the cytosol. The 14 human ZIP family proteins are expressed in a wide variety of tissues and function in many different cellular processes. Many of these proteins (including ZIP1, 2, 3, 4, 5, 6/10, 8, 9, 11, 12, 14) are situated, at least some of the time, on the plasma membrane, where they mediate metal ion uptake into cells. Their level on the cell surface can be controlled rapidly via protein trafficking in response to the ions they transport. For example, the cell surface level of many ZIPs (including ZIP1, 3, 4, 8 and 12) is mediated by the available concentration of zinc. Zinc depletion causes a decrease in endocytosis and degradation, resulting in more ZIP on the surface to take up the essential ion. ZIP levels on the cell surface are a balance between endocytosis, recycling and degradation. We review the trafficking mechanisms of human ZIP proteins, highlighting possible targeting motifs and suggesting a model of zinc-mediated endocytic trafficking. We also provide two possible models for ZIP14 trafficking and degradation.
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Affiliation(s)
- Katherine Bowers
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK
| | - Surjit K S Srai
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK
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56
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Tubular iron deposition and iron handling proteins in human healthy kidney and chronic kidney disease. Sci Rep 2018; 8:9353. [PMID: 29921869 PMCID: PMC6008459 DOI: 10.1038/s41598-018-27107-8] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 05/23/2018] [Indexed: 02/07/2023] Open
Abstract
Iron is suggested to play a detrimental role in the progression of chronic kidney disease (CKD). The kidney recycles iron back into the circulation. However, the localization of proteins relevant for physiological tubular iron handling and their potential role in CKD remain unclear. We examined associations between iron deposition, expression of iron handling proteins and tubular injury in kidney biopsies from CKD patients and healthy controls using immunohistochemistry. Iron was deposited in proximal (PT) and distal tubules (DT) in 33% of CKD biopsies, predominantly in pathologies with glomerular dysfunction, but absent in controls. In healthy kidney, PT contained proteins required for iron recycling including putative iron importers ZIP8, ZIP14, DMT1, iron storage proteins L- and H-ferritin and iron exporter ferroportin, while DT only contained ZIP8, ZIP14, and DMT1. In CKD, iron deposition associated with increased intensity of iron importers (ZIP14, ZIP8), storage proteins (L-, H-ferritin), and/or decreased ferroportin abundance. This demonstrates that tubular iron accumulation may result from increased iron uptake and/or inadequate iron export. Iron deposition associated with oxidative injury as indicated by heme oxygenase-1 abundance. In conclusion, iron deposition is relatively common in CKD, and may result from altered molecular iron handling and may contribute to renal injury.
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57
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Olgar Y, Ozdemir S, Turan B. Induction of endoplasmic reticulum stress and changes in expression levels of Zn 2+-transporters in hypertrophic rat heart. Mol Cell Biochem 2018; 440:209-219. [PMID: 28849306 DOI: 10.1007/s11010-017-3168-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 08/16/2017] [Indexed: 12/15/2022]
Abstract
Clinical and experimental studies have shown an association between intracellular free Zn2+ ([Zn2+]i)-dyshomeostasis and cardiac dysfunction besides [Ca2+]i-dyshomeostasis. Since [Zn2+]i-homeostasis is regulated through Zn2+-transporters depending on their subcellular distributions, one can hypothesize that any imbalance in Zn2+-homeostasis via alteration in Zn2+-transporters may be associated with the induction of ER stress and apoptosis in hypertrophic heart. We used a transverse aortic constriction (TAC) model to induce hypertrophy in young male rat heart. We confirmed the development of hypertrophy with a high ratio of heart to body weight and cardiomyocyte capacitance. The expression levels of ER stress markers GRP78, CHOP/Gadd153, and calnexin are significantly high in TAC-group in comparison to those of controls (SHAM-group). Additionally, we detected high expression levels of apoptotic status marker proteins such as the serine kinase GSK-3β, Bax-to-Bcl-2 ratio, and PUMA in TAC-group in comparison to SHAM-group. The ratios of phospho-Akt to Akt and phospho-NFκB to the NFκB are significantly higher in TAC-group than in SHAM-group. Furthermore, we observed markedly increased phospho-PKCα and PKCα levels in TAC-group. We, also for the first time, determined significantly increased ZIP7, ZIP14, and ZnT8 expressions along with decreased ZIP8 and ZnT7 levels in the heart tissue from TAC-group in comparison to SHAM-group. Furthermore, a roughly calculated total expression level of ZIPs responsible for Zn2+-influx into the cytosol (increased about twofold) can be also responsible for the markedly increased [Zn2+]i detected in hypertrophic cardiomyocytes. Taking into consideration the role of increased [Zn2+]i via decreased ER-[Zn2+] in the induction of ER stress in cardiomyocytes, our present data suggest that differential changes in the expression levels of Zn2+-transporters can underlie mechanical dysfunction, in part due to the induction of ER stress and apoptosis in hypertrophic heart via increased [Zn2+]i- besides [Ca2+]i-dyshomeostasis.
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Affiliation(s)
- Yusuf Olgar
- Ankara University Faculty of Medicine, Ankara, Turkey
| | - Semir Ozdemir
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya, Turkey
| | - Belma Turan
- Ankara University Faculty of Medicine, Ankara, Turkey.
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Aydemir TB, Cousins RJ. The Multiple Faces of the Metal Transporter ZIP14 (SLC39A14). J Nutr 2018; 148:174-184. [PMID: 29490098 PMCID: PMC6251594 DOI: 10.1093/jn/nxx041] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 11/07/2017] [Indexed: 12/14/2022] Open
Abstract
The SLC39A family of metal transporters was identified through homologies with the Zrt- and Irt-like (ZIP) proteins from yeast and plants. Of all the ZIP transporters, ZIP14 is arguably the most robustly characterized in terms of function at the integrative level. Mice with a global knockout of Zip14 are viable, thus providing the opportunity to conduct physiologic experiments. In mice, Zip14 expression is highly tissue specific, with the greatest abundance in the jejunum > liver > heart > kidney > white adipose tissue > skeletal muscle > spleen > pancreas. A unique feature of Zip14 is its upregulation by proinflammatory conditions, particularly increased interleukin 6 (IL-6) and nitric oxide. The transcription factors AP-1, ATF4, and ATF6α are involved in Zip14 regulation. ZIP14 does not appear to be zinc-regulated. The Zip14 knockout phenotype shows multiple sites of ZIP14 function, including the liver, adipose tissue, brain, pancreas, and bone. A prominent feature of the Zip14 ablation is a reduction in intestinal barrier function and onset of metabolic endotoxemia. Many aspects of the phenotype are accentuated with age and accompany increased circulating IL-6. Studies with 65Zn, 59Fe [nontransferrin-bound iron (NTBI)] and 54Mn show that ZIP14 transports these metals. At a steady state, the plasma concentrations of zinc, NTBI, and manganese are such that zinc ions are the major substrate available for ZIP14 at the cell surface. Upregulation of ZIP14 accounts for the hypozincemia and hepatic zinc accumulation associated with acute inflammation and sepsis and is required for liver regeneration and resistance to endoplasmic reticulum (ER) stress. Zip14 ablation in mice produces a defect in manganese excretion that leads to excess manganese accumulation in the brain that produces characteristics of Parkinsonism.
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Affiliation(s)
- Tolunay B Aydemir
- Food Science and Human Nutrition Department and Center for Nutritional
Sciences, College of Agricultural and Life Sciences, University of Florida, Gainesville,
FL,Address correspondence to TBA (e-mail: )
| | - Robert J Cousins
- Food Science and Human Nutrition Department and Center for Nutritional
Sciences, College of Agricultural and Life Sciences, University of Florida, Gainesville,
FL
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59
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Xiao G, Zhou B. ZIP13: A Study of Drosophila Offers an Alternative Explanation for the Corresponding Human Disease. Front Genet 2018; 8:234. [PMID: 29445391 PMCID: PMC5797780 DOI: 10.3389/fgene.2017.00234] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 12/22/2017] [Indexed: 12/16/2022] Open
Abstract
The fruit fly Drosophila melanogaster has become an important model organism to investigate metal homeostasis and human diseases. Previously we identified dZIP13 (CG7816), a member of the ZIP transporter family (SLC39A) and presumably a zinc importer, is in fact physiologically primarily responsible to move iron from the cytosol into the secretory compartments in the fly. This review will discuss the implication of this finding for the etiology of Spondylocheirodysplasia-Ehlers-Danlos Syndrome (SCD–EDS), a human disease defective in ZIP13. We propose an entirely different model in that lack of iron in the secretory compartment may underlie SCD-EDS. Altogether three different working models are discussed, supported by relevant findings made in different studies, with uncertainties, and questions remained to be solved. We speculate that the distinct ZIP13 sequence features, different from those of all other ZIP family members, may confer it special transport properties.
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Affiliation(s)
- Guiran Xiao
- School of Food Science and Engineering, Hefei University of Technology, Hefei, China
| | - Bing Zhou
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing, China
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60
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Olgar Y, Durak A, Tuncay E, Bitirim CV, Ozcinar E, Inan MB, Tokcaer-Keskin Z, Akcali KC, Akar AR, Turan B. Increased free Zn 2+ correlates induction of sarco(endo)plasmic reticulum stress via altered expression levels of Zn 2+ -transporters in heart failure. J Cell Mol Med 2018; 22:1944-1956. [PMID: 29333637 PMCID: PMC5824399 DOI: 10.1111/jcmm.13480] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 10/29/2017] [Indexed: 12/14/2022] Open
Abstract
Zn2+ -homoeostasis including free Zn2+ ([Zn2+ ]i ) is regulated through Zn2+ -transporters and their comprehensive understanding may be important due to their contributions to cardiac dysfunction. Herein, we aimed to examine a possible role of Zn2+ -transporters in the development of heart failure (HF) via induction of ER stress. We first showed localizations of ZIP8, ZIP14 and ZnT8 to both sarcolemma and S(E)R in ventricular cardiomyocytes (H9c2 cells) using confocal together with calculated Pearson's coefficients. The expressions of ZIP14 and ZnT8 were significantly increased with decreased ZIP8 level in HF. Moreover, [Zn2+ ]i was significantly high in doxorubicin-treated H9c2 cells compared to their controls. We found elevated levels of ER stress markers, GRP78 and CHOP/Gadd153, confirming the existence of ER stress. Furthermore, we measured markedly increased total PKC and PKCα expression and PKCα-phosphorylation in HF. A PKC inhibition induced significant decrease in expressions of these ER stress markers compared to controls. Interestingly, direct increase in [Zn2+ ]i using zinc-ionophore induced significant increase in these markers. On the other hand, when we induced ER stress directly with tunicamycin, we could not observe any effect on expression levels of these Zn2+ transporters. Additionally, increased [Zn2+ ]i could induce marked activation of PKCα. Moreover, we observed marked decrease in [Zn2+ ]i under PKC inhibition in H9c2 cells. Overall, our present data suggest possible role of Zn2+ transporters on an intersection pathway with increased [Zn2+ ]i and PKCα activation and induction of HF, most probably via development of ER stress. Therefore, our present data provide novel information how a well-controlled [Zn2+ ]i via Zn2+ transporters and PKCα can be important therapeutic approach in prevention/treatment of HF.
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Affiliation(s)
- Yusuf Olgar
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Aysegul Durak
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Erkan Tuncay
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
| | | | - Evren Ozcinar
- Department of Cardiovascular Surgery, Heart Center, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Mustafa Bahadir Inan
- Department of Cardiovascular Surgery, Heart Center, Ankara University Faculty of Medicine, Ankara, Turkey
| | | | - Kamil Can Akcali
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Ahmet Ruchan Akar
- Department of Cardiovascular Surgery, Heart Center, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Belma Turan
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
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61
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Recent Advances in the Role of SLC39A/ZIP Zinc Transporters In Vivo. Int J Mol Sci 2017; 18:ijms18122708. [PMID: 29236063 PMCID: PMC5751309 DOI: 10.3390/ijms18122708] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 11/27/2017] [Accepted: 12/08/2017] [Indexed: 02/07/2023] Open
Abstract
Zinc (Zn), which is an essential trace element, is involved in numerous mammalian physiological events; therefore, either a deficiency or excess of Zn impairs cellular machineries and influences physiological events, such as systemic growth, bone homeostasis, skin formation, immune responses, endocrine function, and neuronal function. Zn transporters are thought to mainly contribute to Zn homeostasis within cells and in the whole body. Recent genetic, cellular, and molecular studies of Zn transporters highlight the dynamic role of Zn as a signaling mediator linking several cellular events and signaling pathways. Dysfunction in Zn transporters causes various diseases. This review aims to provide an update of Zn transporters and Zn signaling studies and discusses the remaining questions and future directions by focusing on recent progress in determining the roles of SLC39A/ZIP family members in vivo.
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The Tumor Suppressor, P53, Decreases the Metal Transporter, ZIP14. Nutrients 2017; 9:nu9121335. [PMID: 29292794 PMCID: PMC5748785 DOI: 10.3390/nu9121335] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 11/29/2017] [Accepted: 12/04/2017] [Indexed: 12/17/2022] Open
Abstract
Loss of p53’s proper function accounts for over half of identified human cancers. We identified the metal transporter ZIP14 (Zinc-regulated transporter (ZRT) and Iron-regulated transporter (IRT)-like Protein 14) as a p53-regulated protein. ZIP14 protein levels were upregulated by lack of p53 and downregulated by increased p53 expression. This regulation did not fully depend on the changes in ZIP14’s mRNA expression. Co-precipitation studies indicated that p53 interacts with ZIP14 and increases its ubiquitination and degradation. Moreover, knockdown of p53 resulted in higher non-transferrin-bound iron uptake, which was mediated by increased ZIP14 levels. Our study highlights a role for p53 in regulating nutrient metabolism and provides insight into how iron and possibly other metals such as zinc and manganese could be regulated in p53-inactivated tumor cells.
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63
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Gulec A, Gulec S. Ankaferd Influences mRNA Expression of Iron-Regulated Genes During Iron-Deficiency Anemia. Clin Appl Thromb Hemost 2017; 24:960-964. [PMID: 29110513 PMCID: PMC6714724 DOI: 10.1177/1076029617737838] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Ankaferd Blood Stopper (ABS) comprises a mixture of plants and stops bleeding via forming a protein network by erythroid aggregation. Bleeding causes reduction of iron levels in body. It has been indicated that ABS contains significant amount of iron. Thus, we investigated the biological activity of ABS-derived iron on iron-regulated genes during iron-deficiency anemia (IDA). IDA We selected Caco-2 and HepG2 cell lines as in vitro models of human intestine and liver, respectively. Iron deficiency anemia was induced by deferoxamine. The cells were treated with ferric ammonium citrate (FAC) and ABS. Messenger RNA levels of iron-regulated genes were analyzed by quantitative reverse transcription polymerase chain reaction to elucidate whether iron in ABS behaved similar to inorganic iron (FAC) during IDA. The results showed that ABS-derived iron influenced transcriptions of iron-regulated marker genes, including divalent metal transporter (Dmt1), transferrin receptor (TfR), ankyrin repeat domain 37 (Ankrd37), and hepcidin (Hamp) in IDA-induced Caco-2 and HepG2 cells. Our results suggest that when ABS is used to stop tissue bleeding, it might have an ability to reduce levels of IDA.
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Affiliation(s)
- Afife Gulec
- 1 Molecular Nutrition and Human Physiology Laboratory, Food Engineering Department, İzmir Institute of Technology, Urla, İzmir, Turkey
| | - Sukru Gulec
- 1 Molecular Nutrition and Human Physiology Laboratory, Food Engineering Department, İzmir Institute of Technology, Urla, İzmir, Turkey
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Scarl RT, Lawrence CM, Gordon HM, Nunemaker CS. STEAP4: its emerging role in metabolism and homeostasis of cellular iron and copper. J Endocrinol 2017; 234:R123-R134. [PMID: 28576871 PMCID: PMC6166870 DOI: 10.1530/joe-16-0594] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 06/02/2017] [Indexed: 12/28/2022]
Abstract
Preserving energy homeostasis in the presence of stressors such as proinflammatory cytokines and nutrient overload is crucial to maintaining normal cellular function. Six transmembrane epithelial antigen of the prostate 4 (STEAP4), a metalloreductase involved in iron and copper homeostasis, is thought to play a potentially important role in the cellular response to inflammatory stress. Genome-wide association studies have linked various mutations in STEAP4 with the development of metabolic disorders such as obesity, metabolic syndrome and type 2 diabetes. Several studies have shown that expression of Steap4 is modulated by inflammatory cytokines, hormones and other indicators of cellular stress and that STEAP4 may protect cells from damage, helping to maintain normal metabolic function. STEAP4 appears to be particularly relevant in metabolically oriented cells, such as adipocytes, hepatocytes and pancreatic islet cells. These cells struggle to maintain their function in iron or copper overloaded states, presumably due to increased oxidative stress, suggesting STEAP4's role in metal homeostasis is critical to the maintenance of cellular homeostasis in general, and in preventing the onset of metabolic disease. In this review, we explore genetic associations of STEAP4 with metabolic disorders, and we examine STEAP4 tissue expression, subcellular localization, regulation, structure and function as it relates to metabolic diseases. We then examine how STEAP4's role as a regulator of cellular iron and copper may relate to type 2 diabetes.
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Affiliation(s)
- Rachel T Scarl
- Diabetes InstituteHeritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, USA
- Department of Biomedical SciencesHeritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, USA
| | - C Martin Lawrence
- Department of Chemistry and BiochemistryMontana State University, Bozeman, Montana, USA
| | - Hannah M Gordon
- Diabetes InstituteHeritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, USA
- Department of Biomedical SciencesHeritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, USA
| | - Craig S Nunemaker
- Diabetes InstituteHeritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, USA
- Department of Biomedical SciencesHeritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, USA
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65
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Bafaro E, Liu Y, Xu Y, Dempski RE. The emerging role of zinc transporters in cellular homeostasis and cancer. Signal Transduct Target Ther 2017; 2:17029. [PMID: 29218234 PMCID: PMC5661630 DOI: 10.1038/sigtrans.2017.29] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/21/2017] [Accepted: 04/25/2017] [Indexed: 12/21/2022] Open
Abstract
Zinc is an essential micronutrient that plays a role in the structural or enzymatic functions of many cellular proteins. Cellular zinc homeostasis involves the opposing action of two families of metal transporters: the ZnT (SLC30) family that functions to reduce cytoplasmic zinc concentrations and the ZIP (SLC39) family that functions to increase cytoplasmic zinc concentrations. Fluctuations in intracellular zinc levels mediated by these transporter families affect signaling pathways involved in normal cell development, growth, differentiation and death. Consequently, changes in zinc transporter localization and function resulting in zinc dyshomeostasis have pathophysiological effects. Zinc dyshomeostasis has been implicated in the progression of cancer. Here we review recent progress toward understanding the structural basis for zinc transport by ZnT and ZIP family proteins, as well as highlight the roles of zinc as a signaling molecule in physiological conditions and in various cancers. As zinc is emerging as an important signaling molecule in the development and progression of cancer, the ZnT and ZIP transporters that regulate cellular zinc homeostasis are promising candidates for targeted cancer therapy.
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Affiliation(s)
- Elizabeth Bafaro
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Yuting Liu
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Yan Xu
- Department of Obstetrics and Gynecology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Robert E Dempski
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
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66
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Metzendorf C, Zeigerer A, Seifert S, Sparla R, Najafi B, Canonne-Hergaux F, Zerial M, Muckenthaler MU. Acute loss of the hepatic endo-lysosomal system in vivo causes compensatory changes in iron homeostasis. Sci Rep 2017. [PMID: 28642463 PMCID: PMC5481338 DOI: 10.1038/s41598-017-02898-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Liver cells communicate with the extracellular environment to take up nutrients via endocytosis. Iron uptake is essential for metabolic activities and cell homeostasis. Here, we investigated the role of the endocytic system for maintaining iron homeostasis. We specifically depleted the small GTPase Rab5 in the mouse liver, causing a transient loss of the entire endo-lysosomal system. Strikingly, endosome depletion led to a fast reduction of hepatic iron levels, which was preceded by an increased abundance of the iron exporter ferroportin. Compensatory changes in livers of Rab5-depleted mice include increased expression of transferrin receptor 1 as well as reduced expression of the iron-regulatory hormone hepcidin. Serum iron indices (serum iron, free iron binding capacity and total iron binding capacity) in Rab5-KD mice were increased, consistent with an elevated splenic and hepatic iron export. Our data emphasize the critical importance of the endosomal compartments in hepatocytes to maintain hepatic and systemic iron homeostasis in vivo. The short time period (between day four and five) upon which these changes occur underscore the fast dynamics of the liver iron pool.
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Affiliation(s)
- Christoph Metzendorf
- Department of Pediatric Hematology, Oncology and Immunology University of Heidelberg, Heidelberg University Clinic, INF 350, 69120, Heidelberg, Germany.,Molecular Medicine Partnership Unit, 69120, Heidelberg, Germany.,Heidelberg University Biochemistry Center (BZH), INF 327, 69120, Heidelberg, Germany
| | - Anja Zeigerer
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany.,Institute for Diabetes and Cancer, Helmholtz Center for Environmental Health, 85764, Neuherberg, Germany
| | - Sarah Seifert
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany
| | - Richard Sparla
- Department of Pediatric Hematology, Oncology and Immunology University of Heidelberg, Heidelberg University Clinic, INF 350, 69120, Heidelberg, Germany.,Molecular Medicine Partnership Unit, 69120, Heidelberg, Germany
| | - Bahar Najafi
- German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany.,Institute for Diabetes and Cancer, Helmholtz Center for Environmental Health, 85764, Neuherberg, Germany
| | | | - Marino Zerial
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany
| | - Martina U Muckenthaler
- Department of Pediatric Hematology, Oncology and Immunology University of Heidelberg, Heidelberg University Clinic, INF 350, 69120, Heidelberg, Germany. .,Molecular Medicine Partnership Unit, 69120, Heidelberg, Germany.
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67
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Brix KV, Schlekat CE, Garman ER. The mechanisms of nickel toxicity in aquatic environments: An adverse outcome pathway analysis. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2017; 36:1128-1137. [PMID: 27935089 DOI: 10.1002/etc.3706] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 11/13/2016] [Accepted: 11/29/2016] [Indexed: 06/06/2023]
Abstract
Current ecological risk assessment and water quality regulations for nickel (Ni) use mechanistically based, predictive tools such as biotic ligand models (BLMs). However, despite many detailed studies, the precise mechanism(s) of Ni toxicity to aquatic organisms remains elusive. This uncertainty in the mechanism(s) of action for Ni has led to concern over the use of tools like the BLM in some regulatory settings. To address this knowledge gap, the authors used an adverse outcome pathway (AOP) analysis, the first AOP for a metal, to identify multiple potential mechanisms of Ni toxicity and their interactions with freshwater aquatic organisms. The analysis considered potential mechanisms of action based on data from a wide range of organisms in aquatic and terrestrial environments on the premise that molecular initiating events for an essential metal would potentially be conserved across taxa. Through this analysis the authors identified 5 potential molecular initiating events by which Ni may exert toxicity on aquatic organisms: disruption of Ca2+ homeostasis, disruption of Mg2+ homeostasis, disruption of Fe2+/3+ homeostasis, reactive oxygen species-induced oxidative damage, and an allergic-type response of respiratory epithelia. At the organ level of biological organization, these 5 potential molecular initiating events collapse into 3 potential pathways: reduced Ca2+ availability to support formation of exoskeleton, shell, and bone for growth; impaired respiration; and cytotoxicity and tumor formation. At the level of the whole organism, the organ-level responses contribute to potential reductions in growth and reproduction and/or alterations in energy metabolism, with several potential feedback loops between each of the pathways. Overall, the present AOP analysis provides a robust framework for future directed studies on the mechanisms of Ni toxicity and for developing AOPs for other metals. Environ Toxicol Chem 2017;36:1128-1137. © 2016 SETAC.
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Affiliation(s)
- Kevin V Brix
- EcoTox, Miami, Florida, USA
- RSMAS, University of Miami, Miami, Florida, USA
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68
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Amin SN, El-Aidi AA, Zickri MB, Rashed LA, Hassan SS. Hepatoprotective effect of blocking N-methyl-d-aspartate receptors in male albino rats exposed to acute and repeated restraint stress. Can J Physiol Pharmacol 2017; 95:721-731. [PMID: 28317386 DOI: 10.1139/cjpp-2016-0556] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Stress affects many organs in addition to the brain, including the liver. We assessed the effects on the liver of blocking N-methyl-d-aspartate (NMDA) glutamate receptors with memantine in acute and repeated restraint stress. Forty-two male albino rats were divided into 7 groups; control, acute restraint stress (ARS), ARS + memantine, repeated restraint stress, repeated restraint + memantine, and positive control groups. We measured serum iron, zinc, alanine transferase and aspartame transferase, hepatic malondialdehyde, tumor necrosis factor-α (TNF-α), glutathione peroxidase, superoxide dismutase, metallothionein content, zinc transporter ZRT/IRT-like protein 14 mRNA expression, and hepcidin expression. We conducted a histopathological evaluation via histological staining and immunostaining for glial fibrillary acidic protein and synaptophysin expression, both of which are markers of hepatic stellate cell (HSC) activation. Both ARS and repeated stress increased markers of hepatic cell injury, oxidative stress, and HSC activation. Blocking NMDA with memantine provided a hepatoprotective effect in acute and repeated restraint stress and decreased hepatic cell injury, oxidative stress, and HSC activation.
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Affiliation(s)
- Shaimaa Nasr Amin
- a Department of Medical Physiology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | | | - Maha Baligh Zickri
- c Department of Histology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Laila Ahmed Rashed
- d Department of Biochemistry, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Sherif Sabry Hassan
- e Department of Anatomy, Faculty of Medicine, Cairo University, Cairo, Egypt.,f California University of Science and Medicine, School of Medicine, Department of Medical Education, Colton, CA, USA
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69
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Sterling J, Guttha S, Song Y, Song D, Hadziahmetovic M, Dunaief JL. Iron importers Zip8 and Zip14 are expressed in retina and regulated by retinal iron levels. Exp Eye Res 2017; 155:15-23. [PMID: 28057442 PMCID: PMC5359041 DOI: 10.1016/j.exer.2016.12.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 12/30/2016] [Accepted: 12/31/2016] [Indexed: 01/25/2023]
Abstract
Intracellular retinal iron accumulation has been implicated in the pathogenesis of age-related macular degeneration (AMD), the leading cause of irreversible blindness among individuals over the age of 50. Ceruloplasmin/hephaestin double knockout mice (Cp/Heph DKO) and hepcidin knockout mice (Hepc KO) accumulate retinal iron and model some features of AMD. Two canonical pathways govern cellular iron import - transferrin-bound iron import and non-transferrin bound iron import. In Cp/Heph DKO and Hepc KO iron-loaded retinas, transferrin-bound iron import is downregulated. Despite this effort to reduce cellular iron burden, iron continues to accumulate in these retinas in an age-dependent manner. Quantitative RT-PCR and Western analysis were used to quantify the expression of three ferrous iron importers, Dmt1, Zip8, and Zip14, in wild-type (Wt), Cp/Heph DKO, and Hepc KO retinas. Zip8 and Zip14 protein levels were analyzed using Western analysis in mice injected intravitreally with either apo- or holo-transferrin to elucidate one possible mechanism of Zip14 regulation in the retina. Both zip8 and zip14 were expressed in the mouse retina. Paradoxically, protein levels of non-transferrin bound iron importers were upregulated in both Cp/Heph DKO and Hepc KO retinas. Intravitreal holo-transferrin injection decreased Zip 14 protein levels. These data indicate that Zip8 and Zip14 may take up increasing amounts of non-transferrin bound iron in these two mouse models of retinal iron accumulation. Their upregulation in these already iron-loaded retinas suggests a vicious cycle leading to toxicity.
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Affiliation(s)
- Jacob Sterling
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA 19104, USA.
| | - Samyuktha Guttha
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA 19104, USA.
| | - Ying Song
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA 19104, USA.
| | - Delu Song
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA 19104, USA.
| | - Majda Hadziahmetovic
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA 19104, USA.
| | - Joshua L Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA 19104, USA.
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70
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Abstract
Iron is a crucial component of heme- and iron-sulfur clusters, involved in vital cellular functions such as oxygen transport, DNA synthesis, and respiration. Both excess and insufficient levels of iron and heme-precursors cause human disease, such as iron-deficiency anemia, hemochromatosis, and porphyrias. Hence, their levels must be tightly regulated, requiring a complex network of transporters and feedback mechanisms. The use of zebrafish to study these pathways and the underlying genetics offers many advantages, among others their optical transparency, ex-vivo development and high genetic and physiological conservations. This chapter first reviews well-established methods, such as large-scale mutagenesis screens that have led to the initial identification of a series of iron and heme transporters and the generation of a variety of mutant lines. Other widely used techniques are based on injection of RNA, including complementary morpholino knockdown and gene overexpression. In addition, we highlight several recently developed approaches, most notably endonuclease-based gene knockouts such as TALENs or the CRISPR/Cas9 system that have been used to study how loss of function can induce human disease phenocopies in zebrafish. Rescue by chemical complementation with iron-based compounds or small molecules can subsequently be used to confirm causality of the genetic defect for the observed phenotype. All together, zebrafish have proven to be - and will continue to serve as an ideal model to advance our understanding of the pathogenesis of human iron and heme-related diseases and to develop novel therapies to treat these conditions.
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Affiliation(s)
| | - Barry H. Paw
- Brigham & Women’s Hospital, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
- Dana-Farber Cancer Institute, Boston, MA, United States
- Boston Children’s Hospital, Boston, MA, United States
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71
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Abdel-Hafez SII, Nafady NA, Abdel-Rahim IR, Shaltout AM, Daròs JA, Mohamed MA. Assessment of protein silver nanoparticles toxicity against pathogenic Alternaria solani. 3 Biotech 2016; 6:199. [PMID: 28330271 PMCID: PMC5031560 DOI: 10.1007/s13205-016-0515-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 09/08/2016] [Indexed: 01/09/2023] Open
Abstract
Mycogenic synthesis of silver nanoparticles (AgNPs) was carried out in the present investigation using an aqueous extract of endophytic non-pathogenic Alternaria solani F10 (KT721914). The mycosynthesized AgNPs were characterized by means of spectroscopic and microscopic techniques. The surface plasmon resonance found at 430 nm confirmed the formation of stable AgNPs for several weeks at room temperature. Also, the results revealed the formation of spherical and monodispersed AgNPs with an average size of 14.8 ± 1.2 nm. The FT-IR spectrum suggested that the fungal extracellular proteins and secondary metabolites had the role in Ag reduction and AgNPs capping of which protein Ag nanoconjugates were formed. Furthermore, the mycosynthesized AgNPs exhibited potent antifungal activity against different pathogenic isolates of the same Alternaria solani fungus, the causal pathogen of tomato early blight disease. The antifungal efficiency of the AgNPs at 1, 5 and 10 ppm were evaluated for 8 days after incubation by measuring the inhibition rate of fungal radial growth. The results were further supported by investigating fungal hyphae morphology alteration by scanning and transmission electron microscopy. Treated fungal hyphae showed formation of pits and pores. Also, the mycosynthesized AgNPs were able to pass and distribute throughout the fungal cell area and interact with the cell components.
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Affiliation(s)
- Sobhy I I Abdel-Hafez
- Botany and Microbiology Department, Faculty of Science, Assiut University, Assiut, 71516, Egypt
| | - Nivien A Nafady
- Botany and Microbiology Department, Faculty of Science, Assiut University, Assiut, 71516, Egypt.
| | - Ismail R Abdel-Rahim
- Botany and Microbiology Department, Faculty of Science, Assiut University, Assiut, 71516, Egypt
| | - Abeer M Shaltout
- Plant Pathology Research Institute, Agricultural Research Center, Giza, 12655, Egypt
| | - José-Antonio Daròs
- Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia), Avenida de los Naranjos, 46022, Valencia, Spain
| | - Mohamed A Mohamed
- Botany and Microbiology Department, Faculty of Science, Assiut University, Assiut, 71516, Egypt
- Plant Pathology Research Institute, Agricultural Research Center, Giza, 12655, Egypt
- Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia), Avenida de los Naranjos, 46022, Valencia, Spain
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72
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Green Synthesized Silver Nanoparticles: Toxicity Against Poecilia reticulata Fishes and Ceriodaphnia cornuta Crustaceans. J CLUST SCI 2016. [DOI: 10.1007/s10876-016-1126-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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73
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Asperti M, Stuemler T, Poli M, Gryzik M, Lifshitz L, Meyron-Holtz EG, Vlodavsky I, Arosio P. Heparanase Overexpression Reduces Hepcidin Expression, Affects Iron Homeostasis and Alters the Response to Inflammation. PLoS One 2016; 11:e0164183. [PMID: 27711215 PMCID: PMC5053418 DOI: 10.1371/journal.pone.0164183] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 09/21/2016] [Indexed: 01/03/2023] Open
Abstract
Hepcidin is the key regulator of systemic iron availability that acts by controlling the degradation of the iron exporter ferroportin. It is expressed mainly in the liver and regulated by iron, inflammation, erythropoiesis and hypoxia. The various agents that control its expression act mainly via the BMP6/SMAD signaling pathway. Among them are exogenous heparins, which are strong hepcidin repressors with a mechanism of action not fully understood but that may involve the competition with the structurally similar endogenous Heparan Sulfates (HS). To verify this hypothesis, we analyzed how the overexpression of heparanase, the HS degrading enzyme, modified hepcidin expression and iron homeostasis in hepatic cell lines and in transgenic mice. The results showed that transient and stable overexpression of heparanase in HepG2 cells caused a reduction of hepcidin expression and of SMAD5 phosphorylation. Interestingly, the clones showed also altered level of TfR1 and ferritin, indices of a modified iron homeostasis. The heparanase transgenic mice showed a low level of liver hepcidin, an increase of serum and liver iron with a decrease in spleen iron content. The hepcidin expression remained surprisingly low even after treatment with the inflammatory LPS. The finding that modification of HS structure mediated by heparanase overexpression affects hepcidin expression and iron homeostasis supports the hypothesis that HS participate in the mechanisms controlling hepcidin expression.
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Affiliation(s)
- Michela Asperti
- Molecular Biology laboratory, Department of Molecular and Translational Medicine DMMT, University of Brescia, Viale Europa 11, 25123, Brescia, Italy
| | - Tanja Stuemler
- Laboratory for Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Maura Poli
- Molecular Biology laboratory, Department of Molecular and Translational Medicine DMMT, University of Brescia, Viale Europa 11, 25123, Brescia, Italy
| | - Magdalena Gryzik
- Molecular Biology laboratory, Department of Molecular and Translational Medicine DMMT, University of Brescia, Viale Europa 11, 25123, Brescia, Italy
| | - Lena Lifshitz
- Laboratory for Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Esther G. Meyron-Holtz
- Laboratory for Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Israel Vlodavsky
- Cancer and Vascular Biology Research Center, Rappaport Faculty of Medicine, Technion- Israel Institute of Technology, Haifa, 31096, Israel
| | - Paolo Arosio
- Molecular Biology laboratory, Department of Molecular and Translational Medicine DMMT, University of Brescia, Viale Europa 11, 25123, Brescia, Italy
- * E-mail:
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74
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Abstract
Optimal iron nutrition in utero is essential for development of the fetus and helps establish birth iron stores adequate to sustain growth in early infancy. In species with hemochorial placentas, such as humans and rodents, iron in the maternal circulation is transferred to the fetus by directly contacting placental syncytiotrophoblasts. Early kinetic studies provided valuable data on the initial uptake of maternal transferrin, an iron-binding protein, by the placenta. However, the remaining steps of iron trafficking across syncytiotrophoblasts and through the fetal endothelium into the fetal blood remain poorly characterized. Over the last 20 years, identification of transmembrane iron transporters and the iron regulatory hormone hepcidin has greatly expanded the knowledge of cellular iron transport and its regulation by systemic iron status. In addition, emerging human and animal data demonstrating comprised fetal iron stores in severe maternal iron deficiency challenge the classic dogma of exclusive fetal control over the transfer process and indicate that maternal and local signals may play a role in regulating this process. This review compiles current data on the kinetic, molecular, and regulatory aspects of placental iron transport and considers new questions and knowledge gaps raised by these advances.
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Affiliation(s)
- Chang Cao
- C. Cao and M.D. Fleming are with the Department of Pathology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Mark D Fleming
- C. Cao and M.D. Fleming are with the Department of Pathology, Boston Children's Hospital, Boston, Massachusetts, USA.
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75
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Tuschl K, Meyer E, Valdivia LE, Zhao N, Dadswell C, Abdul-Sada A, Hung CY, Simpson MA, Chong WK, Jacques TS, Woltjer RL, Eaton S, Gregory A, Sanford L, Kara E, Houlden H, Cuno SM, Prokisch H, Valletta L, Tiranti V, Younis R, Maher ER, Spencer J, Straatman-Iwanowska A, Gissen P, Selim LAM, Pintos-Morell G, Coroleu-Lletget W, Mohammad SS, Yoganathan S, Dale RC, Thomas M, Rihel J, Bodamer OA, Enns CA, Hayflick SJ, Clayton PT, Mills PB, Kurian MA, Wilson SW. Mutations in SLC39A14 disrupt manganese homeostasis and cause childhood-onset parkinsonism-dystonia. Nat Commun 2016; 7:11601. [PMID: 27231142 PMCID: PMC4894980 DOI: 10.1038/ncomms11601] [Citation(s) in RCA: 204] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 04/12/2016] [Indexed: 02/07/2023] Open
Abstract
Although manganese is an essential trace metal, little is known about its transport and homeostatic regulation. Here we have identified a cohort of patients with a novel autosomal recessive manganese transporter defect caused by mutations in SLC39A14. Excessive accumulation of manganese in these patients results in rapidly progressive childhood-onset parkinsonism-dystonia with distinctive brain magnetic resonance imaging appearances and neurodegenerative features on post-mortem examination. We show that mutations in SLC39A14 impair manganese transport in vitro and lead to manganese dyshomeostasis and altered locomotor activity in zebrafish with CRISPR-induced slc39a14 null mutations. Chelation with disodium calcium edetate lowers blood manganese levels in patients and can lead to striking clinical improvement. Our results demonstrate that SLC39A14 functions as a pivotal manganese transporter in vertebrates.
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Affiliation(s)
- Karin Tuschl
- Genetics and Genomic Medicine, UCL Institute of Child Health, University College London, London WC1N 1EH, UK.,Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Esther Meyer
- Developmental Neurosciences, UCL Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Leonardo E Valdivia
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Ningning Zhao
- Department of Cell, Development and Cancer Biology, Oregon Health &Sciences University, Portland, Oregon 97239, USA
| | - Chris Dadswell
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, UK
| | - Alaa Abdul-Sada
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, UK
| | - Christina Y Hung
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Michael A Simpson
- Division of Genetics and Molecular Medicine, King's College London School of Medicine, London SE1 9RT, UK
| | - W K Chong
- Department of Radiology, Great Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UK
| | - Thomas S Jacques
- Developmental Biology and Cancer, UCL Institute of Child Health and Department of Histopathology, Great Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UK
| | - Randy L Woltjer
- Department of Pathology, Oregon Health &Science University, Portland, Oregon 97239, USA
| | - Simon Eaton
- Developmental Biology and Cancer Programme, UCL Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Allison Gregory
- Department of Molecular &Medical Genetics, Oregon Health &Science University, Portland, Oregon 97239, USA
| | - Lynn Sanford
- Department of Molecular &Medical Genetics, Oregon Health &Science University, Portland, Oregon 97239, USA
| | - Eleanna Kara
- Institute of Neurology, University College London, London WC1N 3BG, UK.,Alzheimer's Disease Research Centre, Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Henry Houlden
- Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Stephan M Cuno
- Institute of Human Genetics, Technische Universität München, Munich 81675, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg 85764, Germany
| | - Holger Prokisch
- Institute of Human Genetics, Technische Universität München, Munich 81675, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg 85764, Germany
| | - Lorella Valletta
- Unit of Molecular Neurogenetics, IRCCS, Foundation Neurological Institute 'C. Besta', Milan 20133, Italy
| | - Valeria Tiranti
- Unit of Molecular Neurogenetics, IRCCS, Foundation Neurological Institute 'C. Besta', Milan 20133, Italy
| | - Rasha Younis
- Department of Medical and Molecular Genetics, University of Birmingham, Birmingham B15 2TT, UK
| | - Eamonn R Maher
- Centre for Rare Diseases and Personalised Medicine, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.,Department of Medical Genetics, School of Clinical Medicine, University of Cambridge, and Cambridge NIHR Biomedical Research Centre, Cambridge CB2 0QQ, UK
| | - John Spencer
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, UK
| | - Ania Straatman-Iwanowska
- MRC Laboratory for Molecular Cell Biology and Cell Biology Unit, University College London, London WC1E 6BT, UK
| | - Paul Gissen
- Genetics and Genomic Medicine, UCL Institute of Child Health, University College London, London WC1N 1EH, UK.,MRC Laboratory for Molecular Cell Biology and Cell Biology Unit, University College London, London WC1E 6BT, UK.,Department of Metabolic Medicine, Great Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UK
| | - Laila A M Selim
- Department of Paediatric Neurology, Faculty of Medicine, Cairo University Children's Hospital, Cairo 11432, Egypt
| | - Guillem Pintos-Morell
- Department of Paediatrics, Section of Paediatric Nephrology, Genetics and Metabolism, Unit of Rare Diseases, University Hospital 'Germans Trias I Pujol', Universitat Autònoma de Barcelona, Badalona 08916, Spain
| | - Wifredo Coroleu-Lletget
- Department of Paediatrics, Paediatric Neurology and Neonatology Unit, University Hospital 'Germans Trias I Pujol', Badalona 08916, Spain
| | - Shekeeb S Mohammad
- Neuroimmunology Group, Institute for Neuroscience and Muscle Research, Kids Research Institute at the Children's Hospital at Westmead, University of Sydney, Westmead NSW 2145, Australia
| | - Sangeetha Yoganathan
- Department of Neurological Sciences, Christian Medical College Hospital, Vellore 632 004, India
| | - Russell C Dale
- Neuroimmunology Group, Institute for Neuroscience and Muscle Research, Kids Research Institute at the Children's Hospital at Westmead, University of Sydney, Westmead NSW 2145, Australia
| | - Maya Thomas
- Department of Neurological Sciences, Christian Medical College Hospital, Vellore 632 004, India
| | - Jason Rihel
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Olaf A Bodamer
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Caroline A Enns
- Department of Cell, Development and Cancer Biology, Oregon Health &Sciences University, Portland, Oregon 97239, USA
| | - Susan J Hayflick
- Department of Molecular &Medical Genetics, Oregon Health &Science University, Portland, Oregon 97239, USA.,Department of Neurology, Oregon Health &Science University, Portland, Oregon 97239, USA.,Department of Pediatrics, Oregon Health &Science University, Portland, Oregon 97239, USA
| | - Peter T Clayton
- Genetics and Genomic Medicine, UCL Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Philippa B Mills
- Genetics and Genomic Medicine, UCL Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Manju A Kurian
- Developmental Neurosciences, UCL Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Stephen W Wilson
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
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76
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Bogdan AR, Miyazawa M, Hashimoto K, Tsuji Y. Regulators of Iron Homeostasis: New Players in Metabolism, Cell Death, and Disease. Trends Biochem Sci 2015; 41:274-286. [PMID: 26725301 DOI: 10.1016/j.tibs.2015.11.012] [Citation(s) in RCA: 586] [Impact Index Per Article: 65.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/16/2015] [Accepted: 11/24/2015] [Indexed: 02/07/2023]
Abstract
Iron is necessary for life, but can also cause cell death. Accordingly, cells evolved a robust, tightly regulated suite of genes for maintaining iron homeostasis. Previous mechanistic studies on iron homeostasis have granted insight into the role of iron in human health and disease. We highlight new regulators of iron metabolism, including iron-trafficking proteins [solute carrier family 39, SLC39, also known as ZRT/IRT-like protein, ZIP; and poly-(rC)-binding protein, PCBP] and a cargo receptor (NCOA4) that is crucial for release of ferritin-bound iron. We also discuss emerging roles of iron in apoptosis and a novel iron-dependent cell death pathway termed 'ferroptosis', the dysregulation of iron metabolism in human pathologies, and the use of iron chelators in cancer therapy.
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Affiliation(s)
- Alexander R Bogdan
- Department of Biological Sciences, North Carolina State University, Campus Box 7633, Raleigh, NC 27695-7633, USA
| | - Masaki Miyazawa
- Department of Biological Sciences, North Carolina State University, Campus Box 7633, Raleigh, NC 27695-7633, USA
| | - Kazunori Hashimoto
- Department of Biological Sciences, North Carolina State University, Campus Box 7633, Raleigh, NC 27695-7633, USA
| | - Yoshiaki Tsuji
- Department of Biological Sciences, North Carolina State University, Campus Box 7633, Raleigh, NC 27695-7633, USA.
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77
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Hennigar SR, McClung JP. Homeostatic regulation of trace mineral transport by ubiquitination of membrane transporters. Nutr Rev 2015; 74:59-67. [PMID: 26611242 DOI: 10.1093/nutrit/nuv060] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 07/12/2015] [Indexed: 02/03/2023] Open
Abstract
Post-translational modification is a critical mechanism by which trace mineral transporters rapidly adapt to their environment to homeostatically regulate ion transport. Recently, a novel pathway was described whereby iron stimulates the ubiquitination and proteasomal degradation of the trace mineral transporter ZIP14. Discovery of this pathway suggests the proteasome as a potential therapeutic target for regulation of iron storage. Moreover, these findings contribute to a theoretical framework that can be applied to other ubiquitinated trace mineral transporters. This review will detail the current state of knowledge regarding the ubiquitination of trace mineral transporters, focusing on iron and zinc transporters, and the potential utility of post-translational modification of trace mineral transporters in the treatment of disease.
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Affiliation(s)
- Stephen R Hennigar
- S.R. Hennigar and J.P. McClung are with the Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - James P McClung
- S.R. Hennigar and J.P. McClung are with the Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA.
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78
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Bailão EFLC, Lima PDS, Silva-Bailão MG, Bailão AM, Fernandes GDR, Kosman DJ, Soares CMDA. Paracoccidioides spp. ferrous and ferric iron assimilation pathways. Front Microbiol 2015; 6:821. [PMID: 26441843 PMCID: PMC4585334 DOI: 10.3389/fmicb.2015.00821] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 07/27/2015] [Indexed: 12/25/2022] Open
Abstract
Iron is an essential micronutrient for almost all organisms, including fungi. Usually, fungi can uptake iron through receptor-mediated internalization of a siderophore or heme, and/or reductive iron assimilation (RIA). Traditionally, the RIA pathway consists of ferric reductases (Fres), ferroxidase (Fet3) and a high-affinity iron permease (Ftr1). Paracoccidioides spp. genomes do not present an Ftr1 homolog. However, this fungus expresses zinc regulated transporter homologs (Zrts), members of the ZIP family of membrane transporters that are able in some organisms to transport zinc and iron. A 2,3,5-triphenyltetrazolium chloride (TTC)-overlay assay indicates that both Pb01 and Pb18 express a ferric reductase activity; however, 59Fe uptake assays indicate that only in Pb18 is this activity coupled to a reductase-dependent iron uptake pathway. In addition, Zrts are up-regulated in iron deprivation, as indicated by RNAseq and qRT-PCR using Pb01 transcripts. RNAseq strategy also demonstrated that transcripts related to siderophore uptake and biosynthesis are up-regulated in iron-deprived condition. The data suggest that the fungus could use both a non-classical RIA, comprising ferric reductases and Fe/Zn permeases (Zrts), and siderophore uptake pathways under iron-limited conditions. The study of iron metabolism reveals novel surface molecules that could function as accessible targets for drugs to block iron uptake and, consequently, inhibit pathogen's proliferation.
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Affiliation(s)
- Elisa Flávia L C Bailão
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás Goiânia, Brazil
| | - Patrícia de Sousa Lima
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás Goiânia, Brazil
| | - Mirelle G Silva-Bailão
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás Goiânia, Brazil
| | - Alexandre M Bailão
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás Goiânia, Brazil
| | | | - Daniel J Kosman
- Department of Biochemistry, School of Medicine and Biomedical Sciences, State University of New York at Buffalo Buffalo, NY, USA
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79
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Jenkitkasemwong S, Wang CY, Coffey R, Zhang W, Chan A, Biel T, Kim JS, Hojyo S, Fukada T, Knutson MD. SLC39A14 Is Required for the Development of Hepatocellular Iron Overload in Murine Models of Hereditary Hemochromatosis. Cell Metab 2015; 22:138-50. [PMID: 26028554 PMCID: PMC4497937 DOI: 10.1016/j.cmet.2015.05.002] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 03/04/2015] [Accepted: 04/24/2015] [Indexed: 01/07/2023]
Abstract
Nearly all forms of hereditary hemochromatosis are characterized by pathological iron accumulation in the liver, pancreas, and heart. These tissues preferentially load iron because they take up non-transferrin-bound iron (NTBI), which appears in the plasma during iron overload. Yet, how tissues take up NTBI is largely unknown. We report that ablation of Slc39a14, the gene coding for solute carrier SLC39A14 (also called ZIP14), in mice markedly reduced the uptake of plasma NTBI by the liver and pancreas. To test the role of SLC39A14 in tissue iron loading, we crossed Slc39a14(-/-) mice with Hfe(-/-) and Hfe2(-/-) mice, animal models of type 1 and type 2 (juvenile) hemochromatosis, respectively. Slc39a14 deficiency in hemochromatotic mice greatly diminished iron loading of the liver and prevented iron deposition in hepatocytes and pancreatic acinar cells. The data suggest that inhibition of SLC39A14 may mitigate hepatic and pancreatic iron loading and associated pathologies in iron overload disorders.
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Affiliation(s)
- Supak Jenkitkasemwong
- Food Science and Human Nutrition Department, University of Florida, Gainesville, FL 32611, USA
| | - Chia-Yu Wang
- Food Science and Human Nutrition Department, University of Florida, Gainesville, FL 32611, USA
| | - Richard Coffey
- Food Science and Human Nutrition Department, University of Florida, Gainesville, FL 32611, USA
| | - Wei Zhang
- Food Science and Human Nutrition Department, University of Florida, Gainesville, FL 32611, USA
| | - Alan Chan
- Food Science and Human Nutrition Department, University of Florida, Gainesville, FL 32611, USA
| | - Thomas Biel
- Department of Surgery, University of Florida, Gainesville, FL 32611, USA
| | - Jae-Sung Kim
- Department of Surgery, University of Florida, Gainesville, FL 32611, USA
| | - Shintaro Hojyo
- RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan; Deutsches Rheuma-Forschungszentrum Berlin, Osteoimmunology, Charitéplatz, 10117 Berlin, Germany
| | - Toshiyuki Fukada
- RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan; Division of Pathology, Department of Oral Diagnostic Sciences, School of Dentistry, Showa University, Shinagawa 142-8666, Japan; Molecular and Cellular Physiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima 770-8055, Japan
| | - Mitchell D Knutson
- Food Science and Human Nutrition Department, University of Florida, Gainesville, FL 32611, USA.
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80
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Tripathi AK, Haldar S, Qian J, Beserra A, Suda S, Singh A, Hopfer U, Chen SG, Garrick MD, Turner JR, Knutson MD, Singh N. Prion protein functions as a ferrireductase partner for ZIP14 and DMT1. Free Radic Biol Med 2015; 84:322-330. [PMID: 25862412 PMCID: PMC4476631 DOI: 10.1016/j.freeradbiomed.2015.03.037] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 03/30/2015] [Accepted: 03/30/2015] [Indexed: 12/21/2022]
Abstract
Excess circulating iron is stored in the liver, and requires reduction of non-Tf-bound iron (NTBI) and transferrin (Tf) iron at the plasma membrane and endosomes, respectively, by ferrireductase (FR) proteins for transport across biological membranes through divalent metal transporters. Here, we report that prion protein (PrP(C)), a ubiquitously expressed glycoprotein most abundant on neuronal cells, functions as a FR partner for divalent-metal transporter-1 (DMT1) and ZIP14. Thus, absence of PrP(C) in PrP-knock-out (PrP(-/-)) mice resulted in markedly reduced liver iron stores, a deficiency that was not corrected by chronic or acute administration of iron by the oral or intraperitoneal routes. Likewise, preferential radiolabeling of circulating NTBI with (59)Fe revealed significantly reduced uptake and storage of NTBI by the liver of PrP(-/-) mice relative to matched PrP(+/+) controls. However, uptake, storage, and utilization of ferritin-bound iron that does not require reduction for uptake were increased in PrP(-/-) mice, indicating a compensatory response to the iron deficiency. Expression of exogenous PrP(C) in HepG2 cells increased uptake and storage of ferric iron (Fe(3+)), not ferrous iron (Fe(2+)), from the medium, supporting the function of PrP(C) as a plasma membrane FR. Coexpression of PrP(C) with ZIP14 and DMT1 in HepG2 cells increased uptake of Fe(3+) significantly, and surprisingly, increased the ratio of N-terminally truncated PrP(C) forms lacking the FR domain relative to full-length PrP(C). Together, these observations indicate that PrP(C) promotes, and possibly regulates, the uptake of NTBI through DMT1 and Zip14 via its FR activity. Implications of these observations for neuronal iron homeostasis under physiological and pathological conditions are discussed.
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Affiliation(s)
- Ajai K. Tripathi
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Swati Haldar
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Juan Qian
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Amber Beserra
- School of Arts and Sciences, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Srinivas Suda
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Ajay Singh
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Ulrich Hopfer
- Department of physiology and Biophysics, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Shu G. Chen
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | | | | | | | - Neena Singh
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
- To whom correspondence should be addressed: Neena Singh, Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, Ohio 44106, USA. Tel: 216-368-2617;
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81
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Wessling-Resnick M. Nramp1 and Other Transporters Involved in Metal Withholding during Infection. J Biol Chem 2015; 290:18984-90. [PMID: 26055722 DOI: 10.1074/jbc.r115.643973] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
During the course of infection, many natural defenses are set up along the boundaries of the host-pathogen interface. Key among these is the host response to withhold metals to restrict the growth of invading microbes. This simple act of nutritional warfare, starving the invader of an essential element, is an effective means of limiting infection. The physiology of metal withholding is often referred to as "nutritional immunity," and the mechanisms of metal transport that contribute to this host response are the focus of this review.
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Affiliation(s)
- Marianne Wessling-Resnick
- From the Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, Massachusetts 02115
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82
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Bresgen N, Eckl PM. Oxidative stress and the homeodynamics of iron metabolism. Biomolecules 2015; 5:808-47. [PMID: 25970586 PMCID: PMC4496698 DOI: 10.3390/biom5020808] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 04/21/2015] [Accepted: 04/22/2015] [Indexed: 12/12/2022] Open
Abstract
Iron and oxygen share a delicate partnership since both are indispensable for survival, but if the partnership becomes inadequate, this may rapidly terminate life. Virtually all cell components are directly or indirectly affected by cellular iron metabolism, which represents a complex, redox-based machinery that is controlled by, and essential to, metabolic requirements. Under conditions of increased oxidative stress—i.e., enhanced formation of reactive oxygen species (ROS)—however, this machinery may turn into a potential threat, the continued requirement for iron promoting adverse reactions such as the iron/H2O2-based formation of hydroxyl radicals, which exacerbate the initial pro-oxidant condition. This review will discuss the multifaceted homeodynamics of cellular iron management under normal conditions as well as in the context of oxidative stress.
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Affiliation(s)
- Nikolaus Bresgen
- Department of Cell Biology, University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria.
| | - Peter M Eckl
- Department of Cell Biology, University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria.
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83
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Ji C, Kosman DJ. Molecular mechanisms of non-transferrin-bound and transferring-bound iron uptake in primary hippocampal neurons. J Neurochem 2015; 133:668-83. [PMID: 25649872 DOI: 10.1111/jnc.13040] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 01/08/2015] [Accepted: 01/14/2015] [Indexed: 12/16/2022]
Abstract
The molecular mechanisms of iron trafficking in neurons have not been elucidated. In this study, we characterized the expression and localization of ferrous iron transporters Zip8, Zip14 and divalent metal transporter 1 (DMT1), and ferrireductases Steap2 and stromal cell-derived receptor 2 in primary rat hippocampal neurons. Steap2 and Zip8 partially co-localize, indicating these two proteins may function in Fe(3+) reduction prior to Fe(2+) permeation. Zip8, DMT1, and Steap2 co-localize with the transferrin receptor/transferrin complex, suggesting they may be involved in transferrin receptor/transferrin-mediated iron assimilation. In brain interstitial fluid, transferring-bound iron (TBI) and non-transferrin-bound iron (NTBI) exist as potential iron sources. Primary hippocampal neurons exhibit significant iron uptake from TBI (Transferrin-(59) Fe(3+)) and NTBI, whether presented as (59) Fe(2+) -citrate or (59) Fe(3+) -citrate; reductase-independent (59) Fe(2+) uptake was the most efficient uptake pathway of the three. Kinetic analysis of Zn(2+) inhibition of Fe(2+) uptake indicated that DMT1 plays only a minor role in the uptake of NTBI. In contrast, localization and knockdown data indicate that Zip8 makes a major contribution. Data suggest also that cell accumulation of (59) Fe from TBI relies at least in part on an endocytosis-independent pathway. These data suggest that Zip8 and Steap2 play a major role in iron accumulation from NTBI and TBI by hippocampal neurons. Analysis of the expression and localization of known iron uptake transporters demonstrated that Zip8 makes a major contribution to iron accumulation in primary cultures of rat embryonic hippocampal neurons. These cells exhibit uptake pathways for ferrous and ferric iron (non-transferrin-bound iron, NTBI in figure) and for transferrin-bound iron; the ferrireductases Steap2 and SDR2 support the uptake of ferric iron substrates. Zip8 and Steap2 are strongly expressed in the plasma membrane of both soma and processes, implying a crucial role in iron accumulation from NTBI and transferrin-bound iron (TBI) by hippocampal neurons.
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Affiliation(s)
- Changyi Ji
- Department of Biochemistry, State University of New York, School of Medicine and Biomedical Sciences Buffalo, Buffalo, New York, USA
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84
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Krenn MA, Schürz M, Teufl B, Uchida K, Eckl PM, Bresgen N. Ferritin-stimulated lipid peroxidation, lysosomal leak, and macroautophagy promote lysosomal "metastability" in primary hepatocytes determining in vitro cell survival. Free Radic Biol Med 2015; 80:48-58. [PMID: 25532933 DOI: 10.1016/j.freeradbiomed.2014.12.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 11/27/2014] [Accepted: 12/04/2014] [Indexed: 12/12/2022]
Abstract
Several pathologies are associated with elevated levels of serum ferritin, for which growth inhibitory properties have been reported; however, the underlying mechanisms are still poorly defined. Previously we have described cytotoxic properties of isoferritins released from primary hepatocytes in vitro, which induce apoptosis in an iron and oxidative stress-dependent mode. Here we show that this ferritin species stimulates endosome clustering and giant endosome formation in primary hepatocytes accompanied by enhanced lysosomal membrane permeability (LMP). In parallel, protein modification by lipid peroxidation-derived 4-hydroxynonenal (HNE) is strongly promoted by ferritin, the HNE-modified proteins (HNE-P) showing remarkable aggregation. Emphasizing the prooxidant context, GSH is rapidly depleted and the GSH/GSSG ratio is substantially declining in ferritin-treated cells. Furthermore, ferritin triggers a transient upregulation of macroautophagy which is abolished by iron chelation and apparently supports HNE-P clearance. Macroautophagy inhibition by 3-methyladenine strongly amplifies ferritin cytotoxicity in a time- and concentration-dependent mode, suggesting an important role of macroautophagy on cellular responses to ferritin endocytosis. Moreover, pointing at an involvement of lysosomal proteolysis, ferritin cytotoxicity and lysosome fragility are aggravated by the protease inhibitor leupeptin. In contrast, EGF which suppresses ferritin-induced cell death attenuates ferritin-mediated LMP. In conclusion, we propose that HNE-P accumulation, lysosome dysfunction, and macroautophagy stimulated by ferritin endocytosis provoke lysosomal "metastability" in primary hepatocytes which permits cell survival as long as in- and extrinsic determinants (e.g., antioxidant availability, damage repair, EGF signaling) keep the degree of lysosomal destabilization below cell death-inducing thresholds.
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Affiliation(s)
- Margit A Krenn
- University of Salzburg, Department of Cell Biology, Hellbrunnerstrasse 34, A-5020 Salzburg, Austria
| | - Melanie Schürz
- University of Salzburg, Department of Cell Biology, Hellbrunnerstrasse 34, A-5020 Salzburg, Austria
| | - Bernhard Teufl
- University of Salzburg, Department of Cell Biology, Hellbrunnerstrasse 34, A-5020 Salzburg, Austria
| | - Koji Uchida
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Peter M Eckl
- University of Salzburg, Department of Cell Biology, Hellbrunnerstrasse 34, A-5020 Salzburg, Austria
| | - Nikolaus Bresgen
- University of Salzburg, Department of Cell Biology, Hellbrunnerstrasse 34, A-5020 Salzburg, Austria.
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85
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Guthrie GJ, Aydemir TB, Troche C, Martin AB, Chang SM, Cousins RJ. Influence of ZIP14 (slc39A14) on intestinal zinc processing and barrier function. Am J Physiol Gastrointest Liver Physiol 2015; 308:G171-8. [PMID: 25428902 PMCID: PMC4312952 DOI: 10.1152/ajpgi.00021.2014] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
ZIP14 is a zinc transport protein with high expression in the small intestine and liver. Zip14 is upregulated during endotoxemia and leads to increased liver zinc content and transient hypozinemia. Since body zinc status and inflammation are associated with changes in intestinal permeability, we hypothesized that ZIP14 may influence intestinal permeability. Wild-type (WT) and Zip14 knockout (KO) mice were used to determine ZIP14-associated intestinal zinc metabolism and effects on permeability. Fractionation of plasma membranes revealed that ZIP14 is localized to the basolateral membrane of enterocytes. Studies utilizing (65)Zn administered by subcutaneous injection revealed greater zinc accumulation in the SI of Zip14 KO mice compared with WT mice. Isolation of endosomes confirmed the presence of ZIP14. Quantification of endosomal zinc concentration by FluoZin-3AM fluorescence demonstrated that zinc is trapped in endosomes of Zip14 KO mice. Intestinal permeability assessed both by plasma FITC-dextran following gavage and by serum endotoxin content was greater in Zip14 KO mice. Threonine phosphorylation of the tight junction protein occludin, which is necessary for tight junction assembly, was reduced in KO mice. Claudin 1 and 2, known to have an inverse relationship in regards to tight junction integrity, reflected impaired barrier function in KO jejunum. These data suggest involvement of ZIP14 in providing zinc for a regulatory role needed for maintenance of the intestinal barrier. In conclusion, ZIP14 is a basolaterally localized protein in enterocytes and is involved in endosomal trafficking of zinc and is necessary for proper maintenance of intestinal tight junctions.
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Affiliation(s)
- Gregory J. Guthrie
- Food Science and Human Nutrition Department and Center for Nutritional Sciences, College of Agricultural and Life Sciences, University of Florida, Gainesville, Florida
| | - Tolunay B. Aydemir
- Food Science and Human Nutrition Department and Center for Nutritional Sciences, College of Agricultural and Life Sciences, University of Florida, Gainesville, Florida
| | - Catalina Troche
- Food Science and Human Nutrition Department and Center for Nutritional Sciences, College of Agricultural and Life Sciences, University of Florida, Gainesville, Florida
| | - Alyssa B. Martin
- Food Science and Human Nutrition Department and Center for Nutritional Sciences, College of Agricultural and Life Sciences, University of Florida, Gainesville, Florida
| | - Shou-Mei Chang
- Food Science and Human Nutrition Department and Center for Nutritional Sciences, College of Agricultural and Life Sciences, University of Florida, Gainesville, Florida
| | - Robert J. Cousins
- Food Science and Human Nutrition Department and Center for Nutritional Sciences, College of Agricultural and Life Sciences, University of Florida, Gainesville, Florida
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86
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Zhao N, Nizzi CP, Anderson SA, Wang J, Ueno A, Tsukamoto H, Eisenstein RS, Enns CA, Zhang AS. Low intracellular iron increases the stability of matriptase-2. J Biol Chem 2014; 290:4432-46. [PMID: 25550162 DOI: 10.1074/jbc.m114.611913] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Matriptase-2 (MT2) is a type II transmembrane serine protease that is predominantly expressed in hepatocytes. It suppresses the expression of hepatic hepcidin, an iron regulatory hormone, by cleaving membrane hemojuvelin into an inactive form. Hemojuvelin is a bone morphogenetic protein (BMP) co-receptor. Here, we report that MT2 is up-regulated under iron deprivation. In HepG2 cells stably expressing the coding sequence of the MT2 gene, TMPRSS6, incubation with apo-transferrin or the membrane-impermeable iron chelator, deferoxamine mesylate salt, was able to increase MT2 levels. This increase did not result from the inhibition of MT2 shedding from the cells. Rather, studies using a membrane-permeable iron chelator, salicylaldehyde isonicotinoyl hydrazone, revealed that depletion of cellular iron was able to decrease the degradation of MT2 independently of internalization. We found that lack of the putative endocytosis motif in its cytoplasmic domain largely abolished the sensitivity of MT2 to iron depletion. Neither acute nor chronic iron deficiency was able to alter the association of Tmprss6 mRNA with polyribosomes in the liver of rats indicating a lack of translational regulation by low iron levels. Studies in mice showed that Tmprss6 mRNA was not regulated by iron nor the BMP-mediated signaling with no evident correlation with either Bmp6 mRNA or Id1 mRNA, a target of BMP signaling. These results suggest that regulation of MT2 occurs at the level of protein degradation rather than by changes in the rate of internalization and translational or transcriptional mechanisms and that the cytoplasmic domain of MT2 is necessary for its regulation.
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Affiliation(s)
- Ningning Zhao
- From the Department of Cell and Developmental Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Christopher P Nizzi
- the Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Sheila A Anderson
- the Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Jiaohong Wang
- the Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, and
| | - Akiko Ueno
- the Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, and
| | - Hidekazu Tsukamoto
- the Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, and the Department of Veteran Affairs, Greater Los Angeles Healthcare System, Los Angeles, California 90073
| | - Richard S Eisenstein
- the Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Caroline A Enns
- From the Department of Cell and Developmental Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - An-Sheng Zhang
- From the Department of Cell and Developmental Biology, Oregon Health and Science University, Portland, Oregon 97239,
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87
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Zhang C, Zhang F. Iron homeostasis and tumorigenesis: molecular mechanisms and therapeutic opportunities. Protein Cell 2014; 6:88-100. [PMID: 25476483 PMCID: PMC4312762 DOI: 10.1007/s13238-014-0119-z] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 11/04/2014] [Indexed: 12/21/2022] Open
Abstract
Excess iron is tightly associated with tumorigenesis in multiple human cancer types through a variety of mechanisms including catalyzing the formation of mutagenic hydroxyl radicals, regulating DNA replication, repair and cell cycle progression, affecting signal transduction in cancer cells, and acting as an essential nutrient for proliferating tumor cells. Thus, multiple therapeutic strategies based on iron deprivation have been developed in cancer therapy. During the past few years, our understanding of genetic association and molecular mechanisms between iron and tumorigenesis has expanded enormously. In this review, we briefly summarize iron homeostasis in mammals, and discuss recent progresses in understanding the aberrant iron metabolism in numerous cancer types, with a focus on studies revealing altered signal transduction in cancer cells.
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Affiliation(s)
- Caiguo Zhang
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, 80045, USA,
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88
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Iron transport across the blood-brain barrier: development, neurovascular regulation and cerebral amyloid angiopathy. Cell Mol Life Sci 2014; 72:709-27. [PMID: 25355056 DOI: 10.1007/s00018-014-1771-4] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/10/2014] [Accepted: 10/23/2014] [Indexed: 12/14/2022]
Abstract
There are two barriers for iron entry into the brain: (1) the brain-cerebrospinal fluid (CSF) barrier and (2) the blood-brain barrier (BBB). Here, we review the literature on developmental iron accumulation by the brain, focusing on the transport of iron through the brain microvascular endothelial cells (BMVEC) of the BBB. We review the iron trafficking proteins which may be involved in the iron flux across BMVEC and discuss the plausible mechanisms of BMVEC iron uptake and efflux. We suggest a model for how BMVEC iron uptake and efflux are regulated and a mechanism by which the majority of iron is trafficked across the developing BBB under the direct guidance of neighboring astrocytes. Thus, we place brain iron uptake in the context of the neurovascular unit of the adult brain. Last, we propose that BMVEC iron is involved in the aggregation of amyloid-β peptides leading to the progression of cerebral amyloid angiopathy which often occurs prior to dementia and the onset of Alzheimer's disease.
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89
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Lane DJR, Richardson DR. The active role of vitamin C in mammalian iron metabolism: much more than just enhanced iron absorption! Free Radic Biol Med 2014; 75:69-83. [PMID: 25048971 DOI: 10.1016/j.freeradbiomed.2014.07.007] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/04/2014] [Accepted: 07/08/2014] [Indexed: 01/18/2023]
Abstract
Ascorbate is a cofactor in numerous metabolic reactions. Humans cannot synthesize ascorbate owing to inactivation of the gene encoding the enzyme l-gulono-γ-lactone oxidase, which is essential for ascorbate synthesis. Accumulating evidence strongly suggests that in addition to the known ability of dietary ascorbate to enhance nonheme iron absorption in the gut, ascorbate within mammalian systems can regulate cellular iron uptake and metabolism. Ascorbate modulates iron metabolism by stimulating ferritin synthesis, inhibiting lysosomal ferritin degradation, and decreasing cellular iron efflux. Furthermore, ascorbate cycling across the plasma membrane is responsible for ascorbate-stimulated iron uptake from low-molecular-weight iron-citrate complexes, which are prominent in the plasma of individuals with iron-overload disorders. Importantly, this iron-uptake pathway is of particular relevance to astrocyte brain iron metabolism and tissue iron loading in disorders such as hereditary hemochromatosis and β-thalassemia. Recent evidence also indicates that ascorbate is a novel modulator of the classical transferrin-iron uptake pathway, which provides almost all iron for cellular demands and erythropoiesis under physiological conditions. Ascorbate acts to stimulate transferrin-dependent iron uptake by an intracellular reductive mechanism, strongly suggesting that it may act to stimulate iron mobilization from the endosome. The ability of ascorbate to regulate transferrin iron uptake could help explain the metabolic defect that contributes to ascorbate-deficiency-induced anemia.
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Affiliation(s)
- Darius J R Lane
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, University of Sydney, Sydney, NSW 2006, Australia.
| | - Des R Richardson
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, University of Sydney, Sydney, NSW 2006, Australia.
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90
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Philpott CC, Ryu MS. Special delivery: distributing iron in the cytosol of mammalian cells. Front Pharmacol 2014; 5:173. [PMID: 25101000 PMCID: PMC4106451 DOI: 10.3389/fphar.2014.00173] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 07/04/2014] [Indexed: 01/19/2023] Open
Abstract
Eukaryotic cells contain hundreds of proteins that require iron cofactors for activity. These iron enzymes are located in essentially every subcellular compartment; thus, iron cofactors must travel to every compartment in the cell. Iron cofactors exist in three basic forms: Heme, iron–sulfur clusters, and simple iron ions (also called non-heme iron). Iron ions taken up by the cell initially enter a kinetically labile, exchangeable pool that is referred to as the labile iron pool. The majority of the iron in this pool is delivered to mitochondria, where it is incorporated into heme and iron–sulfur clusters, as well as non-heme iron enzymes. These cofactors must then be distributed to nascent proteins in the mitochondria, cytosol, and membrane-bound organelles. Emerging evidence suggests that specific systems exist for the distribution of iron cofactors within the cell. These systems include membrane transporters, protein chaperones, specialized carriers, and small molecules. This review focuses on the distribution of iron ions in the cytosol and will highlight differences between the iron distribution systems of simple eukaryotes and mammalian cells.
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Affiliation(s)
- Caroline C Philpott
- Genetics and Metabolism Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health Bethesda, MD, USA
| | - Moon-Suhn Ryu
- Genetics and Metabolism Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health Bethesda, MD, USA
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91
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Zhang C. Essential functions of iron-requiring proteins in DNA replication, repair and cell cycle control. Protein Cell 2014; 5:750-60. [PMID: 25000876 PMCID: PMC4180463 DOI: 10.1007/s13238-014-0083-7] [Citation(s) in RCA: 180] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 05/04/2014] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic cells contain numerous iron-requiring proteins such as iron-sulfur (Fe-S) cluster proteins, hemoproteins and ribonucleotide reductases (RNRs). These proteins utilize iron as a cofactor and perform key roles in DNA replication, DNA repair, metabolic catalysis, iron regulation and cell cycle progression. Disruption of iron homeostasis always impairs the functions of these iron-requiring proteins and is genetically associated with diseases characterized by DNA repair defects in mammals. Organisms have evolved multi-layered mechanisms to regulate iron balance to ensure genome stability and cell development. This review briefly provides current perspectives on iron homeostasis in yeast and mammals, and mainly summarizes the most recent understandings on iron-requiring protein functions involved in DNA stability maintenance and cell cycle control.
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Affiliation(s)
- Caiguo Zhang
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, 80045, USA,
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92
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Coates TD. Physiology and pathophysiology of iron in hemoglobin-associated diseases. Free Radic Biol Med 2014; 72:23-40. [PMID: 24726864 PMCID: PMC4940047 DOI: 10.1016/j.freeradbiomed.2014.03.039] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 03/26/2014] [Accepted: 03/27/2014] [Indexed: 01/19/2023]
Abstract
Iron overload and iron toxicity, whether because of increased absorption or iron loading from repeated transfusions, can be major causes of morbidity and mortality in a number of chronic anemias. Significant advances have been made in our understanding of iron homeostasis over the past decade. At the same time, advances in magnetic resonance imaging have allowed clinicians to monitor and quantify iron concentrations noninvasively in specific organs. Furthermore, effective iron chelators are now available, including preparations that can be taken orally. This has resulted in substantial improvement in mortality and morbidity for patients with severe chronic iron overload. This paper reviews the key points of iron homeostasis and attempts to place clinical observations in patients with transfusional iron overload in context with the current understanding of iron homeostasis in humans.
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Affiliation(s)
- Thomas D Coates
- Children׳s Center for Cancer and Blood Diseases, Children׳s Hospital Los Angeles, University of Southern California Keck School of Medicine, Los Angeles, CA 90027, USA.
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93
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An iron-regulated and glycosylation-dependent proteasomal degradation pathway for the plasma membrane metal transporter ZIP14. Proc Natl Acad Sci U S A 2014; 111:9175-80. [PMID: 24927598 DOI: 10.1073/pnas.1405355111] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Protein degradation is instrumental in regulating cellular function. Plasma membrane proteins targeted for degradation are internalized and sorted to multivesicular bodies, which fuse with lysosomes, where they are degraded. ZIP14 is a newly identified iron transporter with multitransmembrane domains. In an attempt to dissect the molecular mechanisms by which iron regulates ZIP14 levels, we found that ZIP14 is endocytosed, extracted from membranes, deglycosylated, and degraded by proteasomes. This pathway did not depend on the retrograde trafficking to the endoplasmic reticulum and thus did not involve the well-defined endoplasmic reticulum-associated protein degradation pathway. Iron inhibited membrane extraction of internalized ZIP14, resulting in higher steady-state levels of ZIP14. Asparagine-linked (N-linked) glycosylation of ZIP14, particularly the glycosylation at N102, was required for efficient membrane extraction of ZIP14 and therefore is necessary for its iron sensitivity. These findings highlight the importance of proteasomes in the degradation of endocytosed plasma membrane proteins.
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94
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Gálvez-Peralta M, Wang Z, Bao S, Knoell DL, Nebert DW. Tissue-Specific Induction of Mouse ZIP8 and ZIP14 Divalent Cation/Bicarbonate Symporters by, and Cytokine Response to, Inflammatory Signals. Int J Toxicol 2014; 33:246-258. [PMID: 24728862 DOI: 10.1177/1091581814529310] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Mouse Slc39a8 and Slc39a14 genes encode ZIP8 and ZIP14, respectively, which are ubiquitous divalent cation/(HCO3-)2 symporters responsible for uptake of Zn2+, Fe2+, and Mn2+ into cells. Cd2+ and other toxic nonessential metals can displace essential cations, thereby entering vertebrate cells. Whereas Slc39a8 encodes a single protein, Slc39a14 has 2 exons 4 which, via alternative splicing, give rise to ZIP14A and ZIP14B; why differences exist in cell type-specific expression of ZIP14A and ZIP14B remains unknown. Inflammatory stimuli have been associated with upregulation of ZIP8 and ZIP14, but a systematic study of many tissues simultaneously in a laboratory animal following inflammatory cytokine exposure has not yet been reported. Herein, we show that C57BL/6J male mice--treated intraperitoneally with lipopolysaccharide or the proinflammatory cytokines tumor necrosis factor (TNF) or interleukin-6 (IL6)--exhibited quantatively very different, highly tissue-specific, and markedly time-dependent up- and downregulation of ZIP8, ZIP14A, and ZIP14B messenger RNA (mRNA) levels in 12 tissues. The magnitude of inflammatory response was confirmed by measuring the proinflammatory cytokine TNF, IL6, and interleukin-1β mRNA levels in the same tissues of these animals. Our data suggest that most if not all tissues use ZIP8, ZIP14A, and/or ZIP14B for Zn2+ uptake, some tissues under basal conditions and others moreso when inflammatory stressors are present; collectively, this might lead to substantial alterations in plasma Zn2+ levels due to Zn2+ redistribution not just in liver but across many vital organs. In the context of cadmium-mediated toxicity, our data suggest that tissues other than liver, kidney, and lung should also be considered.
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Affiliation(s)
- Marina Gálvez-Peralta
- Department of Environmental Health, Center for Environmental Genetics, University of Cincinnati Medical Center, Cincinnati, OH, USA.,Present address: Department of Basic Pharmaceutical Sciences, West Virginia University, Morgantown, WV, USA
| | - Zhifang Wang
- Department of Environmental Health, Center for Environmental Genetics, University of Cincinnati Medical Center, Cincinnati, OH, USA.,Present address: Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, People's Republic of China
| | - Shengying Bao
- David Heart and Lung Research Institute, Ohio State University, Columbus, OH, USA
| | - Daren L Knoell
- David Heart and Lung Research Institute, Ohio State University, Columbus, OH, USA
| | - Daniel W Nebert
- Department of Environmental Health, Center for Environmental Genetics, University of Cincinnati Medical Center, Cincinnati, OH, USA
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95
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Worthen CA, Enns CA. The role of hepatic transferrin receptor 2 in the regulation of iron homeostasis in the body. Front Pharmacol 2014; 5:34. [PMID: 24639653 PMCID: PMC3944196 DOI: 10.3389/fphar.2014.00034] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 02/18/2014] [Indexed: 12/22/2022] Open
Abstract
Fine-tuning of body iron is required to prevent diseases such as iron-overload and anemia. The putative iron sensor, transferrin receptor 2 (TfR2), is expressed in the liver and mutations in this protein result in the iron-overload disease Type III hereditary hemochromatosis (HH). With the loss of functional TfR2, the liver produces about 2-fold less of the peptide hormone hepcidin, which is responsible for negatively regulating iron uptake from the diet. This reduction in hepcidin expression leads to the slow accumulation of iron in the liver, heart, joints, and pancreas and subsequent cirrhosis, heart disease, arthritis, and diabetes. TfR2 can bind iron-loaded transferrin (Tf) in the bloodstream, and hepatocytes treated with Tf respond with a 2-fold increase in hepcidin expression through stimulation of the bone morphogenetic protein (BMP)-signaling pathway. Loss of functional TfR2 or its binding partner, the original HH protein, results in a loss of this transferrin-sensitivity. While much is known about the trafficking and regulation of TfR2, the mechanism of its transferrin-sensitivity through the BMP-signaling pathway is still not known.
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Affiliation(s)
- Christal A Worthen
- Department of Cell and Developmental Biology, Oregon Health and Science University Portland, OR, USA
| | - Caroline A Enns
- Department of Cell and Developmental Biology, Oregon Health and Science University Portland, OR, USA
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96
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Frazer DM, Anderson GJ. The regulation of iron transport. Biofactors 2014; 40:206-14. [PMID: 24132807 DOI: 10.1002/biof.1148] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 09/02/2013] [Accepted: 09/06/2013] [Indexed: 01/01/2023]
Abstract
Iron is an essential nutrient, but its concentration and distribution in the body must be tightly controlled due to its inherent toxicity and insolubility in aqueous solution. Living systems have successfully overcome these potential limitations by evolving a range of iron binding proteins and transport systems that effectively maintain iron in a nontoxic and soluble form for much, if not all, of its time within the body. In the circulation, iron is transported to target organs bound to the serum iron binding protein transferrin. Individual cells modulate their uptake of transferrin-bound iron depending on their iron requirements, using both transferrin receptor 1-dependent and independent pathways. Once inside the cell, iron can be chaperoned to sites of need or, if in excess, stored within ferritin. Iron is released from cells by the iron export protein ferroportin1, which requires the ferroxidase activity of ceruloplasmin or hephestin to load iron safely onto transferrin. The regulation of iron export is controlled predominantly at the systemic level by the master regulator of iron homeostasis hepcidin. Hepcidin, in turn, responds to changes in body iron demand, making use of a range of regulatory mechanisms that center on the bone morphogenetic protein signaling pathway. This review provides an overview of recent advances in the field of iron metabolism and outlines the key components of the iron transport and regulation systems.
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Affiliation(s)
- David M Frazer
- Iron Metabolism Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Qld, Australia
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97
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Montalbetti N, Dalghi MG, Albrecht C, Hediger MA. Nutrient transport in the mammary gland: calcium, trace minerals and water soluble vitamins. J Mammary Gland Biol Neoplasia 2014; 19:73-90. [PMID: 24567109 DOI: 10.1007/s10911-014-9317-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 01/22/2014] [Indexed: 01/19/2023] Open
Abstract
Milk nutrients are secreted by epithelial cells in the alveoli of the mammary gland by several complex and highly coordinated systems. Many of these nutrients are transported from the blood to the milk via transcellular pathways that involve the concerted activity of transport proteins on the apical and basolateral membranes of mammary epithelial cells. In this review, we focus on transport mechanisms that contribute to the secretion of calcium, trace minerals and water soluble vitamins into milk with particular focus on the role of transporters of the SLC series as well as calcium transport proteins (ion channels and pumps). Numerous members of the SLC family are involved in the regulation of essential nutrients in the milk, such as the divalent metal transporter-1 (SLC11A2), ferroportin-1 (SLC40A1) and the copper transporter CTR1 (SLC31A1). A deeper understanding of the physiology and pathophysiology of these transporters will be of great value for drug discovery and treatment of breast diseases.
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Affiliation(s)
- Nicolas Montalbetti
- Institute of Biochemistry and Molecular Medicine, and Swiss National Centre of Competence in Research, NCCR TransCure, University of Bern, Bühlstrasse 28, 3012, Bern, Switzerland,
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98
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Giorgi G, Roque ME. Iron overload induces changes of pancreatic and duodenal divalent metal transporter 1 and prohepcidin expression in mice. Acta Histochem 2014; 116:354-62. [PMID: 24083991 DOI: 10.1016/j.acthis.2013.08.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 08/21/2013] [Accepted: 08/22/2013] [Indexed: 02/06/2023]
Abstract
It is well known that the iron content of the body is tightly regulated. Iron excess induces adaptive changes that are differentially regulated in each tissue. The pancreas is particularly susceptible to iron-related disorders. We studied the expression and regulation of key iron proteins in the pancreas, duodenum and liver, using an animal model of iron overload (female CF1 mice injected i.p. with iron saccharate, colloidal iron form). Divalent metal transporter 1, prohepcidin and ferritin (pancreas, duodenum, liver) were assessed by immunohistochemistry; divalent metal transporter 1 (pancreas, duodenum) by Western blot. In the iron overloaded mice, prohepcidin expression increased in islets of Langerhans and hepatocytes, and divalent metal transporter 1 expression decreased in cells of islets and in enterocytes. In the iron overloaded mice, ferritin expression decreased in islets of Langerhans and increased in acinar cells; hemosiderin was localized in connective tissue cells. The inverse relationship between divalent metal transporter 1 and prohepcidin may indicate a negative regulation by hepcidin, and hence reduction of iron stores in islets of Langerhans. Our data showed that in iron overloaded mice model, induced by colloidal iron form, a coordinated expression of key iron proteins in the pancreas, duodenum and liver may occur. Further research will be necessary to determine the adaptive responses induced by iron in the pancreas.
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99
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Liuzzi JP, Yoo C. Role of zinc in the regulation of autophagy during ethanol exposure in human hepatoma cells. Biol Trace Elem Res 2013; 156:350-6. [PMID: 24061963 DOI: 10.1007/s12011-013-9816-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 09/02/2013] [Indexed: 02/07/2023]
Abstract
Faulty autophagy has been linked to various diseases including neurodegenerative disorders, diabetes, and cancer. Increasing evidence support the notion that activation of autophagy protects against ethanol-induced steatosis and liver injury. Herein, we investigated the role of zinc in autophagy in human hepatoma cells VL-17A exposed or not to ethanol. LC3II/LC3I ratio, p62, and Beclin-1 expression and autophagosomes number were determined in cells incubated in medium containing various concentrations of zinc with or without ethanol. In addition, labile zinc and mRNA expression of metallothionein and the zinc transporters SLC39A8, SLC39A14, and SLC30A10 were evaluated in cells exposed to ethanol and the autophagy inhibitor 3-methyladenine. Zinc depletion caused a significant suppression of autophagy in cells. Conversely, zinc addition to medium stimulated autophagy in cells. Moreover, cotreatment with ethanol and excess zinc (40 μM) had an additive effect on the induction of autophagy. 3-methyadenine treatment decreased labile zinc, but this effect was more pronounced in cells exposed to ethanol. Lastly, ethanol and 3-methyladenine caused significant changes in the expression of metallothionein and zinc transporters. The results from this study support the hypothesis that zinc is critical for autophagy under basal conditions and during ethanol exposure.
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Affiliation(s)
- J P Liuzzi
- Department of Dietetics and Nutrition, Florida International University, Miami, USA,
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100
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Abstract
Iron is an essential nutrient that is tightly regulated. A principal function of the liver is the regulation of iron homeostasis. The liver senses changes in systemic iron requirements and can regulate iron concentrations in a robust and rapid manner. The last 10 years have led to the discovery of several regulatory mechanisms in the liver that control the production of iron regulatory genes, storage capacity, and iron mobilization. Dysregulation of these functions leads to an imbalance of iron, which is the primary cause of iron-related disorders. Anemia and iron overload are two of the most prevalent disorders worldwide and affect over a billion people. Several mutations in liver-derived genes have been identified, demonstrating the central role of the liver in iron homeostasis. During conditions of excess iron, the liver increases iron storage and protects other tissues, namely, the heart and pancreas from iron-induced cellular damage. However, a chronic increase in liver iron stores results in excess reactive oxygen species production and liver injury. Excess liver iron is one of the major mechanisms leading to increased steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma.
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Affiliation(s)
- Erik R Anderson
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
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