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Pardridge WM. A Historical Review of Brain Drug Delivery. Pharmaceutics 2022; 14:1283. [PMID: 35745855 PMCID: PMC9229021 DOI: 10.3390/pharmaceutics14061283] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 12/13/2022] Open
Abstract
The history of brain drug delivery is reviewed beginning with the first demonstration, in 1914, that a drug for syphilis, salvarsan, did not enter the brain, due to the presence of a blood-brain barrier (BBB). Owing to restricted transport across the BBB, FDA-approved drugs for the CNS have been generally limited to lipid-soluble small molecules. Drugs that do not cross the BBB can be re-engineered for transport on endogenous BBB carrier-mediated transport and receptor-mediated transport systems, which were identified during the 1970s-1980s. By the 1990s, a multitude of brain drug delivery technologies emerged, including trans-cranial delivery, CSF delivery, BBB disruption, lipid carriers, prodrugs, stem cells, exosomes, nanoparticles, gene therapy, and biologics. The advantages and limitations of each of these brain drug delivery technologies are critically reviewed.
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Affiliation(s)
- William M Pardridge
- Department of Medicine, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
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2
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Adverse effects of iron deficiency anemia on pregnancy outcome and offspring development and intervention of three iron supplements. Sci Rep 2021; 11:1347. [PMID: 33446747 PMCID: PMC7809104 DOI: 10.1038/s41598-020-79971-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 12/15/2020] [Indexed: 11/09/2022] Open
Abstract
Iron deficiency anemia (IDA) is a common micronutrient deficiency among pregnant women with severe consequences including impaired immuno-inflammatory system, premature birth, fetal death etc. The present study aimed to investigate the effects of three iron supplements on IDA female rats and their offspring. The IDA female rat model was established with low iron diet and the rats were then mated. After pregnancy, rats were fed diets containing different iron supplements (iron polysaccharide complex, iron protein succinylate and ferrous sulfate) until their offspring were 42 days old. Pregnancy outcomes, haematological, iron metabolism, physical and neurological development indexes were determined. The results showed that all three iron supplements improved the levels of hematological parameters of both mother and offspring rats. After iron supplementation, serum iron, transferrin saturation and serum ferritin levels were increased compared with the IDA group. The level of ferritin light chain in the liver and spleen of both mother and offspring rats in iron supplemented groups was significantly higher than that of the IDA group. The average number of born alive per litter in the iron treatment groups was significantly higher than that in the IDA group. Iron supplements also improved the physical growth and neurobehavioral development of offspring rats. It was also found that iron supplementation improved the expression of ferritin light chain and the synaptic growth associated proteins in the brain and hippocampus. No significant difference was found in the efficacy of three iron supplements. These results suggest that pregnant and postpartum IDA affects pregnancy outcomes, offspring physical development and causes neural impairment. Sufficient iron supplementation can significantly improve IDA and its adverse effects on both mother and offspring.
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3
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Radziejewska A, Suliburska J, Kołodziejski P, Chmurzynska A. Role of Slc19a1 and Tfr2 in liver transport of iron and folate: A rat model of folate/iron deficiency followed by supplementation. J Trace Elem Med Biol 2020; 62:126568. [PMID: 32521439 DOI: 10.1016/j.jtemb.2020.126568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 05/18/2020] [Accepted: 05/22/2020] [Indexed: 12/28/2022]
Abstract
The aim of this study was to determine how folate and iron deficiency, and the subsequent supplementation of rats' diet with these nutrients, affects Slc19a1and Tfr2 gene expression and the metabolism of folate and iron. After 28 days of iron-folate deficiency 150 female rats were randomized into five experimental groups receiving a diet deficient in folic acid (FA), an iron-supplemented diet (DFE), an iron-deficient diet supplemented with FA (DFOL), a diet supplemented with iron and FA (FEFOL), and a diet deficient in iron and FA (D); there was also a control group (C). Samples were collected on days 2, 10, and 21 of the experiment. After two days of supplementation, Tfr2 mRNA level were 78 % lower in the DFE group than in the C group (p < 0.05); after 10 days, TfR2 levels in the FEFOL group were 82 % lower than in the C and the DFE group (p < 0.01). However, we did not find any differences at the protein level at any time-point. Hepcidin concentrations were higher in the DFE and the DFEFOL groups than in the D group after 21 days of supplementation (p < 0.01). Transcript and protein abundance of Slc19a1 gene did not differ between the groups at any time-point. Iron metabolism was affected by iron and folate deficiency and subsequent supplementation with these micronutrients, but TFR2 protein was not involved in the regulatory mechanism. Hepcidin expression can be are upregulated after 21 days of supplementation with 150 mg of iron/ kg of diet.
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Affiliation(s)
- Anna Radziejewska
- Institute of Human Nutrition and Dietetics, Poznan University of Life Sciences, Wojska Polskiego 31, 60-624 Poznan, Poland
| | - Joanna Suliburska
- Institute of Human Nutrition and Dietetics, Poznan University of Life Sciences, Wojska Polskiego 31, 60-624 Poznan, Poland
| | - Paweł Kołodziejski
- Department of Animal Physiology and Biochemistry, Poznan University of Life Sciences, 35 Wolynska Street, 60-637 Poznan, Poland
| | - Agata Chmurzynska
- Institute of Human Nutrition and Dietetics, Poznan University of Life Sciences, Wojska Polskiego 31, 60-624 Poznan, Poland.
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4
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Jiang D, Lee H, Pardridge WM. Plasmid DNA gene therapy of the Niemann-Pick C1 mouse with transferrin receptor-targeted Trojan horse liposomes. Sci Rep 2020; 10:13334. [PMID: 32770132 PMCID: PMC7414904 DOI: 10.1038/s41598-020-70290-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 07/27/2020] [Indexed: 01/25/2023] Open
Abstract
Niemann-Pick C1 (NPC1) is a lysosomal cholesterol storage disorder, that severely affects the brain, and is caused by mutations in the NPC1 gene, which encodes an intracellular membrane transporter of non-esterified cholesterol. Therapeutic options for NPC1 are few, and classical enzyme replacement therapy with the recombinant protein is not possible as the NPC1 gene product is an insoluble membrane protein, which increases the need for development of gene therapy for NPC1. While viral based gene therapy is under development, it is important to investigate alternative approaches to brain gene therapy without viral vectors. The present work develops a plasmid DNA approach to gene therapy of NPC1 using Trojan horse liposomes (THLs), wherein the plasmid DNA is encapsulated in 100 nm pegylated liposomes, which are targeted to organs with a monoclonal antibody against the mouse transferrin receptor. THLs were encapsulated with a 8.0 kb plasmid DNA encoding the 3.9 kb human NPC1 open reading frame, under the influence of a 1.5 kb platelet derived growth factor B (PDGFB) promoter. THLs were administered weekly beginning at 6–7 weeks in the NPC1−/− null mouse, and delivery of the plasmid DNA, and NPC1 mRNA expression in brain, spleen, and liver were confirmed by quantitative PCR. THL treatment reduced tissue inclusion bodies in brain, and peripheral organs, but did not prolong lifespan in these mice. The work suggests that early treatment after birth may be required to reverse this disease model with NPC1 gene replacement therapy.
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Affiliation(s)
- Dahai Jiang
- The Lipogene Company, 2649 Townsgate Road, Thousand Oaks, CA, 91361, USA
| | - Hungyen Lee
- The Lipogene Company, 2649 Townsgate Road, Thousand Oaks, CA, 91361, USA
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5
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van Vuren AJ, van Wijk R, van Beers EJ, Marx JJ. Liver Iron Retention Estimated from Utilization of Oral and Intravenous Radioiron in Various Anemias and Hemochromatosis in Humans. Int J Mol Sci 2020; 21:ijms21031077. [PMID: 32041196 PMCID: PMC7037197 DOI: 10.3390/ijms21031077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 01/28/2020] [Accepted: 02/04/2020] [Indexed: 01/19/2023] Open
Abstract
Patients with hereditary hemochromatosis and non-transfusion-dependent hereditary anemia develop predominantly liver iron-overload. We present a unique method allowing quantification of liver iron retention in humans during first-pass of 59Fe-labeled iron through the portal system, using standard ferrokinetic techniques measuring red cell iron uptake after oral and intravenous 59Fe administration. We present data from patients with iron deficiency (ID; N = 47), hereditary hemochromatosis (HH; N = 121) and non-transfusion-dependent hereditary anemia (HA; N = 40). Mean mucosal iron uptake and mucosal iron transfer (±SD) were elevated in patients with HH (59 ± 18%, 80 ± 15% respectively), HA (65 ± 17%, 74 ± 18%) and ID (84 ± 14%, 94 ± 6%) compared to healthy controls (43 ± 19%, 64 ± 18%) (p < 0.05) resulting in increased iron retention after 14 days compared to healthy controls in all groups (p < 0.01). The fraction of retained iron utilized for red cell production was 0.37 ± 0.17 in untreated HA, 0.55 ± 0.20 in untreated HH and 0.99 ± 0.22 in ID (p < 0.01). Interestingly, compared to red blood cell iron utilization after oral iron administration, red blood cell iron utilization was higher after injection of transferrin-bound iron in HA and HH. Liver iron retention was considerably higher in HH and HA compared to ID. We hypothesize that albumin serves as a scavenger of absorbed Fe(II) for delivering albumin-bound Fe(III) to hepatocytes.
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Affiliation(s)
- Annelies J. van Vuren
- Van Creveldkliniek, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Richard van Wijk
- Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Eduard J. van Beers
- Van Creveldkliniek, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
- Correspondence: ; Tel.: +31-88-755-84-50
| | - Joannes J.M. Marx
- Departments of Haematology and Internal Medicine, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
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Greene CJ, Attwood K, Sharma NJ, Gross KW, Smith GJ, Xu B, Kauffman EC. Transferrin receptor 1 upregulation in primary tumor and downregulation in benign kidney is associated with progression and mortality in renal cell carcinoma patients. Oncotarget 2017; 8:107052-107075. [PMID: 29291011 PMCID: PMC5739796 DOI: 10.18632/oncotarget.22323] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 08/31/2017] [Indexed: 12/19/2022] Open
Abstract
The central dysregulated pathway of clear cell (cc) renal cell carcinoma (RCC), the von Hippel Lindau/hypoxia inducible factor-α axis, is a key regulator of intracellular iron levels, however the role of iron uptake in human RCC tumorigenesis and progression remains unknown. We conducted a thorough, large-scale investigation of the expression and prognostic significance of the primary iron uptake protein, transferrin receptor 1 (TfR1/CD71/TFRC), in RCC patients. TfR1 immunohistochemistry was performed in over 1500 cores from 574 renal cell tumor patient tissues (primary tumors, matched benign kidneys, metastases) and non-neoplastic tissues from 36 different body sites. TfR1 levels in RCC tumors, particularly ccRCC, were significantly associated with adverse clinical prognostic features (anemia, lower body mass index, smoking), worse tumor pathology (size, stage, grade, multifocality, sarcomatoid dedifferentiation) and worse survival outcomes, including after adjustments for tumor pathology. Highest TfR1 tissue levels in the non-gravid body were detected in benign renal tubule epithelium. Opposite to TfR1 changes in the primary tumor, TfR1 levels in benign kidney dropped during tumor progression and were inversely associated with worse survival outcomes, independent of tumor pathology. Quantitative measurement of TfR1 subcellular localization in cell lines demonstrated mixed cytoplasmic and membranous expression with increased TfR1 in clusters in ccRCC versus benign renal cell lines. Results of this study support an important role for TfR1 in RCC progression and identify TfR1 as a novel RCC biomarker and therapeutic target.
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Affiliation(s)
| | - Kristopher Attwood
- Department of Biostatistics and Bioinformatics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
| | - Nitika J. Sharma
- Department of Urology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
| | - Kenneth W. Gross
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
| | - Gary J. Smith
- Department of Urology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
| | - Bo Xu
- Department of Pathology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
| | - Eric C. Kauffman
- Department of Urology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
- Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14214, USA
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7
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Bettencourt C, Forabosco P, Wiethoff S, Heidari M, Johnstone DM, Botía JA, Collingwood JF, Hardy J, Milward EA, Ryten M, Houlden H. Gene co-expression networks shed light into diseases of brain iron accumulation. Neurobiol Dis 2016; 87:59-68. [PMID: 26707700 PMCID: PMC4731015 DOI: 10.1016/j.nbd.2015.12.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 11/18/2015] [Accepted: 12/14/2015] [Indexed: 12/21/2022] Open
Abstract
Aberrant brain iron deposition is observed in both common and rare neurodegenerative disorders, including those categorized as Neurodegeneration with Brain Iron Accumulation (NBIA), which are characterized by focal iron accumulation in the basal ganglia. Two NBIA genes are directly involved in iron metabolism, but whether other NBIA-related genes also regulate iron homeostasis in the human brain, and whether aberrant iron deposition contributes to neurodegenerative processes remains largely unknown. This study aims to expand our understanding of these iron overload diseases and identify relationships between known NBIA genes and their main interacting partners by using a systems biology approach. We used whole-transcriptome gene expression data from human brain samples originating from 101 neuropathologically normal individuals (10 brain regions) to generate weighted gene co-expression networks and cluster the 10 known NBIA genes in an unsupervised manner. We investigated NBIA-enriched networks for relevant cell types and pathways, and whether they are disrupted by iron loading in NBIA diseased tissue and in an in vivo mouse model. We identified two basal ganglia gene co-expression modules significantly enriched for NBIA genes, which resemble neuronal and oligodendrocytic signatures. These NBIA gene networks are enriched for iron-related genes, and implicate synapse and lipid metabolism related pathways. Our data also indicates that these networks are disrupted by excessive brain iron loading. We identified multiple cell types in the origin of NBIA disorders. We also found unforeseen links between NBIA networks and iron-related processes, and demonstrate convergent pathways connecting NBIAs and phenotypically overlapping diseases. Our results are of further relevance for these diseases by providing candidates for new causative genes and possible points for therapeutic intervention.
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Affiliation(s)
- Conceição Bettencourt
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK; Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK.
| | - Paola Forabosco
- Istituto di Ricerca Genetica e Biomedica CNR, Cagliari, Italy
| | - Sarah Wiethoff
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK; Center for Neurology and Hertie Institute for Clinical Brain Research, Eberhard-Karls-University, Tübingen, Germany
| | - Moones Heidari
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia; Centre for Bioinformatics, Biomarker Discovery and Information-Based Medicine, The University of Newcastle, Callaghan, NSW, Australia
| | - Daniel M Johnstone
- Bosch Institute and Discipline of Physiology, University of Sydney, NSW, Australia
| | - Juan A Botía
- Department of Medical and Molecular Genetics, King's College London, London, UK
| | | | - John Hardy
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Elizabeth A Milward
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia; Centre for Bioinformatics, Biomarker Discovery and Information-Based Medicine, The University of Newcastle, Callaghan, NSW, Australia
| | - Mina Ryten
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK; Department of Medical and Molecular Genetics, King's College London, London, UK
| | - Henry Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
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8
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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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Abstract
Neonatal hemochromatosis is a clinical condition in which severe liver disease in the newborn is accompanied by extrahepatic siderosis. Gestational alloimmune liver disease (GALD) has been established as the cause of fetal liver injury resulting in nearly all cases of NH. In GALD, a women is exposed to a fetal antigen that she does not recognize as "self" and subsequently begins to produce IgG antibodies that are directed against fetal hepatocytes. These antibodies bind to fetal liver antigen and activate the terminal complement cascade resulting in hepatocyte injury and death. GALD can cause congenital cirrhosis or acute liver failure with and without iron overload and siderosis. Practitioners should consider GALD in cases of fetal demise, stillbirth, and neonatal acute liver failure. Identification of infants with GALD is important as treatment is available and effective for subsequent pregnancies.
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Affiliation(s)
- Amy G. Feldman
- Address for correspondence. Amy G. Feldman, MD, Ann & Robert H. Lurie Children's Hospital of Chicago, 225 East Chicago Avenue, Box 57, Chicago, IL 60611-2605, United States. Tel.: +1 312 227 7600; fax: +1 312 227 9645.
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10
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Abstract
Iron is essential for all known life due to its redox properties; however, these same properties can also lead to its toxicity in overload through the production of reactive oxygen species. Robust systemic and cellular control are required to maintain safe levels of iron, and the liver seems to be where this regulation is mainly located. Iron misregulation is implicated in many diseases, and as our understanding of iron metabolism improves, the list of iron-related disorders grows. Recent developments have resulted in greater knowledge of the fate of iron in the body and have led to a detailed map of its metabolism; however, a quantitative understanding at the systems level of how its components interact to produce tight regulation remains elusive. A mechanistic computational model of human liver iron metabolism, which includes the core regulatory components, is presented here. It was constructed based on known mechanisms of regulation and on their kinetic properties, obtained from several publications. The model was then quantitatively validated by comparing its results with previously published physiological data, and it is able to reproduce multiple experimental findings. A time course simulation following an oral dose of iron was compared to a clinical time course study and the simulation was found to recreate the dynamics and time scale of the systems response to iron challenge. A disease state simulation of haemochromatosis was created by altering a single reaction parameter that mimics a human haemochromatosis gene (HFE) mutation. The simulation provides a quantitative understanding of the liver iron overload that arises in this disease. This model supports and supplements understanding of the role of the liver as an iron sensor and provides a framework for further modelling, including simulations to identify valuable drug targets and design of experiments to improve further our knowledge of this system. Iron is an essential nutrient required for healthy life but, in excess, is the cause of debilitating and even fatal conditions. The most common genetic disorder in humans caused by a mutation, haemochromatosis, results in an iron overload in the liver. Indeed, the liver plays a central role in the regulation of iron. Recently, an increasing amount of detail has been discovered about molecules related to iron metabolism, but an understanding of how they work together and regulate iron levels (in healthy people) or fail to do it (in disease) is still missing. We present a mathematical model of the regulation of liver iron metabolism that provides explanations of its dynamics and allows further hypotheses to be formulated and later tested in experiments. Importantly, the model reproduces accurately the healthy liver iron homeostasis and simulates haemochromatosis, showing how the causative mutation leads to iron overload. We investigate how best to control iron regulation and identified reactions that can be targets of new medicines to treat iron overload. The model provides a virtual laboratory for investigating iron metabolism and improves understanding of the method by which the liver senses and controls iron levels.
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Chua ACG, Klopcic BRS, Ho DS, Fu SK, Forrest CH, Croft KD, Olynyk JK, Lawrance IC, Trinder D. Dietary iron enhances colonic inflammation and IL-6/IL-11-Stat3 signaling promoting colonic tumor development in mice. PLoS One 2013; 8:e78850. [PMID: 24223168 PMCID: PMC3819375 DOI: 10.1371/journal.pone.0078850] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 09/16/2013] [Indexed: 12/18/2022] Open
Abstract
Chronic intestinal inflammation and high dietary iron are associated with colorectal cancer development. The role of Stat3 activation in iron-induced colonic inflammation and tumorigenesis was investigated in a mouse model of inflammation-associated colorectal cancer. Mice, fed either an iron-supplemented or control diet, were treated with azoxymethane and dextran sodium sulfate (DSS). Intestinal inflammation and tumor development were assessed by endoscopy and histology, gene expression by real-time PCR, Stat3 phosphorylation by immunoblot, cytokines by ELISA and apoptosis by TUNEL assay. Colonic inflammation was more severe in mice fed an iron-supplemented compared with a control diet one week post-DSS treatment, with enhanced colonic IL-6 and IL-11 release and Stat3 phosphorylation. Both IL-6 and ferritin, the iron storage protein, co-localized with macrophages suggesting iron may act directly on IL-6 producing-macrophages. Iron increased DSS-induced colonic epithelial cell proliferation and apoptosis consistent with enhanced mucosal damage. DSS-treated mice developed anemia that was not alleviated by dietary iron supplementation. Six weeks post-DSS treatment, iron-supplemented mice developed more and larger colonic tumors compared with control mice. Intratumoral IL-6 and IL-11 expression increased in DSS-treated mice and IL-6, and possibly IL-11, were enhanced by dietary iron. Gene expression of iron importers, divalent metal transporter 1 and transferrin receptor 1, increased and iron exporter, ferroportin, decreased in colonic tumors suggesting increased iron uptake. Dietary iron and colonic inflammation synergistically activated colonic IL-6/IL-11-Stat3 signaling promoting tumorigenesis. Oral iron therapy may be detrimental in inflammatory bowel disease since it may exacerbate colonic inflammation and increase colorectal cancer risk.
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Affiliation(s)
- Anita C. G. Chua
- School of Medicine and Pharmacology, Fremantle Hospital, University of Western Australia, Fremantle, Western Australia, Australia
- Western Australian Institute for Medical Research, Perth, Western Australia, Australia
- * E-mail:
| | - Borut R. S. Klopcic
- School of Medicine and Pharmacology, Fremantle Hospital, University of Western Australia, Fremantle, Western Australia, Australia
- Centre for Inflammatory Bowel Diseases, Fremantle Hospital, Fremantle, Western Australia, Australia
| | - Desiree S. Ho
- School of Medicine and Pharmacology, Fremantle Hospital, University of Western Australia, Fremantle, Western Australia, Australia
- Western Australian Institute for Medical Research, Perth, Western Australia, Australia
| | - S. Kristine Fu
- School of Medicine and Pharmacology, Fremantle Hospital, University of Western Australia, Fremantle, Western Australia, Australia
- Centre for Inflammatory Bowel Diseases, Fremantle Hospital, Fremantle, Western Australia, Australia
| | - Cynthia H. Forrest
- Department of Histopathology, PathWest, Fremantle Hospital, Fremantle, Western Australia, Australia
- School of Pathology and Laboratory Medicine, University of Western Australia, Perth, Western Australia, Australia
| | - Kevin D. Croft
- School of Medicine and Pharmacology, Royal Perth Hospital, University of Western Australia, Perth, Western Australia, Australia
| | - John K. Olynyk
- Department of Gastroenterology, Fremantle Hospital, Fremantle, Western Australia, Australia
- Institute for Immunology and Infectious Diseases, Murdoch University, Murdoch, Western Australia, Australia
- Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia
| | - Ian C. Lawrance
- School of Medicine and Pharmacology, Fremantle Hospital, University of Western Australia, Fremantle, Western Australia, Australia
- Centre for Inflammatory Bowel Diseases, Fremantle Hospital, Fremantle, Western Australia, Australia
| | - Debbie Trinder
- School of Medicine and Pharmacology, Fremantle Hospital, University of Western Australia, Fremantle, Western Australia, Australia
- Western Australian Institute for Medical Research, Perth, Western Australia, Australia
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Zhao N, Enns CA. N-linked glycosylation is required for transferrin-induced stabilization of transferrin receptor 2, but not for transferrin binding or trafficking to the cell surface. Biochemistry 2013; 52:3310-9. [PMID: 23556518 PMCID: PMC3656769 DOI: 10.1021/bi4000063] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Transferrin receptor 2 (TfR2) is
a member of the transferrin receptor-like
family of proteins. Mutations in TfR2 can lead to a rare form of the
iron overload disease, hereditary hemochromatosis. TfR2 is proposed
to sense body iron levels and increase the level of expression of
the iron regulatory hormone, hepcidin. Human TfR2 (hTfR2) contains
four potential Asn-linked (N-linked) glycosylation sites on its ectodomain.
The importance of glycosylation in TfR2 function has not been elucidated.
In this study, by employing site-directed mutagenesis to remove glycosylation
sites of hTfR2 individually or in combination, we found that hTfR2
was glycosylated at Asn 240, 339, and 754, while the consensus sequence
for N-linked glycosylation at Asn 540 was not utilized. Cell surface
protein biotinylation and biotin-labeled Tf indicated that in the
absence of N-linked oligosaccharides, hTfR2 still moved to the plasma
membrane and bound its ligand, holo-Tf. However, without N-linked
glycosylation, hTfR2 did not form the intersubunit disulfide bonds
as efficiently as the wild type (WT). Moreover, the unglycosylated
form of hTfR2 could not be stabilized by holo-Tf. We further provide
evidence that the unglycosylated hTfR2 behaved in manner different
from that of the WT in response to holo-Tf treatment. Thus, the putative
iron-sensing function of TfR2 could not be achieved in the absence
of N-linked oligosaccharides. On the basis of our analyses, we conclude
that unlike TfR1, N-linked glycosylation is dispensable for the cell
surface expression and holo-Tf binding, but it is required for efficient
intersubunit disulfide bond formation and holo-Tf-induced stabilization
of TfR2.
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Affiliation(s)
- Ningning Zhao
- Department of Cell and Developmental Biology, Oregon Health & Science University , Portland, Oregon 97239, United States
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Lane DJR, Chikhani S, Richardson V, Richardson DR. Transferrin iron uptake is stimulated by ascorbate via an intracellular reductive mechanism. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1527-41. [PMID: 23481043 DOI: 10.1016/j.bbamcr.2013.02.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 02/14/2013] [Accepted: 02/15/2013] [Indexed: 02/08/2023]
Abstract
Although ascorbate has long been known to stimulate dietary iron (Fe) absorption and non-transferrin Fe uptake, the role of ascorbate in transferrin Fe uptake is unknown. Transferrin is a serum Fe transport protein supplying almost all cellular Fe under physiological conditions. We sought to examine ascorbate's role in this process, particularly as cultured cells are typically ascorbate-deficient. At typical plasma concentrations, ascorbate significantly increased (59)Fe uptake from transferrin by 1.5-2-fold in a range of cells. Moreover, ascorbate enhanced ferritin expression and increased (59)Fe accumulation in ferritin. The lack of effect of cycloheximide or the cytosolic aconitase inhibitor, oxalomalate, on ascorbate-mediated (59)Fe uptake from transferrin indicate increased ferritin synthesis or cytosolic aconitase activity was not responsible for ascorbate's activity. Experiments with membrane-permeant and -impermeant ascorbate-oxidizing reagents indicate that while extracellular ascorbate is required for stimulation of (59)Fe uptake from (59)Fe-citrate, only intracellular ascorbate is needed for transferrin (59)Fe uptake. Additionally, experiments with l-ascorbate analogs indicate ascorbate's reducing ene-diol moiety is necessary for its stimulatory activity. Importantly, neither N-acetylcysteine nor buthionine sulfoximine, which increase or decrease intracellular glutathione, respectively, affected transferrin-dependent (59)Fe uptake. Thus, ascorbate's stimulatory effect is not due to a general increase in cellular reducing capacity. Ascorbate also did not affect expression of transferrin receptor 1 or (125)I-transferrin cellular flux. However, transferrin receptors, endocytosis, vacuolar-type ATPase activity and endosomal acidification were required for ascorbate's stimulatory activity. Therefore, ascorbate is a novel modulator of the classical transferrin Fe uptake pathway, acting via an intracellular reductive mechanism.
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Affiliation(s)
- Darius J R Lane
- Department of Pathology, University of Sydney, Sydney, New South Wales, Australia.
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Nam H, Wang CY, Zhang L, Zhang W, Hojyo S, Fukada T, Knutson MD. ZIP14 and DMT1 in the liver, pancreas, and heart are differentially regulated by iron deficiency and overload: implications for tissue iron uptake in iron-related disorders. Haematologica 2013; 98:1049-57. [PMID: 23349308 DOI: 10.3324/haematol.2012.072314] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The liver, pancreas, and heart are particularly susceptible to iron-related disorders. These tissues take up plasma iron from transferrin or non-transferrin-bound iron, which appears during iron overload. Here, we assessed the effect of iron status on the levels of the transmembrane transporters, ZRT/IRT-like protein 14 and divalent metal-ion transporter-1, which have both been implicated in transferrin- and non-transferrin-bound iron uptake. Weanling male rats (n=6/group) were fed an iron-deficient, iron-adequate, or iron-overloaded diet for 3 weeks. ZRT/IRT-like protein 14, divalent metal-ion transporter-1 protein and mRNA levels in liver, pancreas, and heart were determined by using immunoblotting and quantitative reverse transcriptase polymerase chain reaction analysis. Confocal immunofluorescence microscopy was used to localize ZRT/IRT-like protein 14 in the liver and pancreas. ZRT/IRT-like protein 14 and divalent metal-ion transporter-1 protein levels were also determined in hypotransferrinemic mice with genetic iron overload. Hepatic ZRT/IRT-like protein 14 levels were found to be 100% higher in iron-loaded rats than in iron-adequate controls. By contrast, hepatic divalent metal-ion transporter-1 protein levels were 70% lower in iron-overloaded animals and nearly 3-fold higher in iron-deficient ones. In the pancreas, ZRT/IRT-like protein 14 levels were 50% higher in iron-overloaded rats, and in the heart, divalent metal-ion transporter-1 protein levels were 4-fold higher in iron-deficient animals. At the mRNA level, ZRT/IRT-like protein 14 expression did not vary with iron status, whereas divalent metal-ion transporter-1 expression was found to be elevated in iron-deficient livers. Immunofluorescence staining localized ZRT/IRT-like protein 14 to the basolateral membrane of hepatocytes and to acinar cells of the pancreas. Hepatic ZRT/IRT-like protein 14, but not divalent metal-ion transporter-1, protein levels were elevated in iron-loaded hypotransferrinemic mice. In conclusion, ZRT/IRT-like protein 14 protein levels are up-regulated in iron-loaded rat liver and pancreas and in hypotransferrinemic mouse liver. Divalent metal-ion transporter-1 protein levels are down-regulated in iron-loaded rat liver, and up-regulated in iron-deficient liver and heart. Our results provide insight into the potential contributions of these transporters to tissue iron uptake during iron deficiency and overload.
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Affiliation(s)
- Hyeyoung Nam
- Food Science & Human Nutrition Department, University of Florida, Gainesville, FL, USA
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Acikyol B, Graham RM, Trinder D, House MJ, Olynyk JK, Scott RJ, Milward EA, Johnstone DM. Brain transcriptome perturbations in the transferrin receptor 2 mutant mouse support the case for brain changes in iron loading disorders, including effects relating to long-term depression and long-term potentiation. Neuroscience 2013; 235:119-28. [PMID: 23333676 DOI: 10.1016/j.neuroscience.2013.01.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 12/14/2012] [Accepted: 01/02/2013] [Indexed: 11/16/2022]
Abstract
Iron abnormalities within the brain are associated with several rare but severe neurodegenerative conditions. There is growing evidence that more common systemic iron loading disorders such as hemochromatosis can also have important effects on the brain. To identify features that are common across different forms of hemochromatosis, we used microarray and real-time reverse transcription polymerase chain reaction (RT-PCR) to assess brain transcriptome profiles of transferrin receptor 2 mutant mice (Tfr2(mut)), a model of a rare type of hereditary hemochromatosis, relative to wildtype control mice. The results were compared with our previous findings in dietary iron-supplemented wildtype mice and Hfe(-/-) mice, a model of a common type of hereditary hemochromatosis. For transcripts showing significant changes relative to controls across all three models, there was perfect (100%) directional concordance (i.e. transcripts were increased in all models or decreased in all models). Comparison of the two models of hereditary hemochromatosis, which showed more pronounced changes than the dietary iron-supplemented mice, revealed numerous common molecular effects. Pathway analyses highlighted changes for genes relating to long-term depression (6.8-fold enrichment, p=5.4×10(-7)) and, to a lesser extent, long-term potentiation (3.7-fold enrichment, p=0.01), with generalized reductions in transcription of key genes from these pathways, which are involved in modulating synaptic strength and efficacy and are essential for memory and learning. The agreement across the models suggests the findings are robust and strengthens previous evidence that iron loading disorders affect the brain. Perturbations of brain phenomena such as long-term depression and long-term potentiation might partly explain neurologic symptoms reported for some hemochromatosis patients.
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Affiliation(s)
- B Acikyol
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia
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Delima RD, Chua ACG, Tirnitz-Parker JEE, Gan EK, Croft KD, Graham RM, Olynyk JK, Trinder D. Disruption of hemochromatosis protein and transferrin receptor 2 causes iron-induced liver injury in mice. Hepatology 2012; 56:585-93. [PMID: 22383097 DOI: 10.1002/hep.25689] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 02/19/2012] [Indexed: 12/21/2022]
Abstract
UNLABELLED Mutations in hemochromatosis protein (HFE) or transferrin receptor 2 (TFR2) cause hereditary hemochromatosis (HH) by impeding production of the liver iron-regulatory hormone, hepcidin (HAMP). This study examined the effects of disruption of Hfe or Tfr2, either alone or together, on liver iron loading and injury in mouse models of HH. Iron status was determined in Hfe knockout (Hfe(-/-)), Tfr2 Y245X mutant (Tfr2(mut)), and double-mutant (Hfe(-/-) ×Tfr2(mut) ) mice by measuring plasma and liver iron levels. Plasma alanine transaminase (ALT) activity, liver histology, and collagen deposition were evaluated to assess liver injury. Hepatic oxidative stress was assessed by measuring superoxide dismutase (SOD) activity and F(2)-isoprostane levels. Gene expression was measured by real-time polymerase chain reaction. Hfe(-/-) ×Tfr2(mut) mice had elevated hepatic iron with a periportal distribution and increased plasma iron, transferrin saturation, and non-transferrin-bound iron, compared with Hfe(-/-), Tfr2(mut), and wild-type (WT) mice. Hamp1 expression was reduced to 40% (Hfe(-/-) and Tfr2(mut) ) and 1% (Hfe(-/-) ×Tfr2(mut)) of WT values. Hfe(-/-) ×Tfr2(mut) mice had elevated plasma ALT activity and mild hepatic inflammation with scattered aggregates of infiltrating inflammatory cluster of differentiation 45 (CD45)-positive cells. Increased hepatic hydoxyproline levels as well as Sirius red and Masson's Trichrome staining demonstrated advanced portal collagen deposition. Hfe(-/-) and Tfr2(mut) mice had less hepatic inflammation and collagen deposition. Liver F(2) -isoprostane levels were elevated, and copper/zinc and manganese SOD activities decreased in Hfe(-/-) ×Tfr2(mut), Tfr2(mut), and Hfe(-/-) mice, compared with WT mice. CONCLUSION Disruption of both Hfe and Tfr2 caused more severe hepatic iron overload with more advanced lipid peroxidation, inflammation, and portal fibrosis than was observed with the disruption of either gene alone. The Hfe(-/-) ×Tfr2(mut) mouse model of iron-induced liver injury reflects the liver injury phenotype observed in human HH.
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Affiliation(s)
- Roheeth D Delima
- School of Medicine and Pharmacology, Fremantle Hospital, University of Western Australia, Fremantle, Western Australia, Australia
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Factors influencing disease phenotype and penetrance in HFE haemochromatosis. Hum Genet 2010; 128:233-48. [DOI: 10.1007/s00439-010-0852-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Accepted: 06/16/2010] [Indexed: 01/24/2023]
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