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Kohzuki H, Ito H, Kurokawa H, Matsui H, Yamamoto T, Ishikawa E. Reactive oxygen species induced by indomethacin enhance accumulation of heme carrier protein 1 and hematoporphyrin accumulation in vitro and in vivo in a brain tumor model. J Clin Biochem Nutr 2024; 74:207-212. [PMID: 38799142 PMCID: PMC11111468 DOI: 10.3164/jcbn.23-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 01/17/2024] [Indexed: 05/29/2024] Open
Abstract
Photodynamic therapy (PDT) is useful for various cancers such as high-grade glioma and cancers of other organs. However, the mechanism of tumor-specific accumulation of porphyrin is not clear. The authors previously reported that heme carrier protein 1 (HCP1) contributes to the transport of porphyrins; specifically, we showed that the production of cancer-specific reactive oxygen species from mitochondria (mitROS) leads in turn to enhanced HCP1 expression. Indomethacin (IND), a non-steroidal anti-inflammatory drug, increases ROS production by affecting mitochondrial electron transfer system. In the present work, the authors investigated the effect of pretreatment with IND on cancer-specific porphyrin accumulation, using both a glioma cell line and a rat brain tumor model. This work demonstrated that exposure of a rat glioma cell to IND results in increased generation of cancer-specific mitROS and accumulation of HCP1 expression and porphyrin concentration. Additionally, systemic dosing of a brain tumor animal model with IND resulted in elevated cellular accumulation of porphyrin in tumor cell. This is an effect not seen with normal brain tissue. Thus, the administration of IND increases intracellular porphyrin concentrations in tumor cell without exerting harmful effects on normal brain tissue, and increased porphyrin concentration in tumor cell may lead to improved PDT effect.
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Affiliation(s)
- Hidehiro Kohzuki
- Graduate School of Comprehensive Human Sciences, Doctoral Program in Clinical Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
- Department of Neurosurgery, Institute of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Hiromu Ito
- Quantum RedOx Chemistry Team, Institute for Quantum Life Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Hiromi Kurokawa
- Department of Gastroenterology, Institute of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Hirofumi Matsui
- Department of Gastroenterology, Institute of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Tetsuya Yamamoto
- Department of Neurosurgery, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama, Kanagawa 236-0027, Japan
| | - Eiichi Ishikawa
- Department of Neurosurgery, Institute of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
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2
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Roth-Walter F. Iron-Deficiency in Atopic Diseases: Innate Immune Priming by Allergens and Siderophores. FRONTIERS IN ALLERGY 2022; 3:859922. [PMID: 35769558 PMCID: PMC9234869 DOI: 10.3389/falgy.2022.859922] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 03/03/2022] [Indexed: 12/12/2022] Open
Abstract
Although iron is one of the most abundant elements on earth, about a third of the world's population are affected by iron deficiency. Main drivers of iron deficiency are beside the chronic lack of dietary iron, a hampered uptake machinery as a result of immune activation. Macrophages are the principal cells distributing iron in the human body with their iron restriction skewing these cells to a more pro-inflammatory state. Consequently, iron deficiency has a pronounced impact on immune cells, favoring Th2-cell survival, immunoglobulin class switching and primes mast cells for degranulation. Iron deficiency during pregnancy increases the risk of atopic diseases in children, while both children and adults with allergy are more likely to have anemia. In contrast, an improved iron status seems to protect against allergy development. Here, the most important interconnections between iron metabolism and allergies, the effect of iron deprivation on distinct immune cell types, as well as the pathophysiology in atopic diseases are summarized. Although the main focus will be humans, we also compare them with innate defense and iron sequestration strategies of microbes, given, particularly, attention to catechol-siderophores. Similarly, the defense and nutritional strategies in plants with their inducible systemic acquired resistance by salicylic acid, which further leads to synthesis of flavonoids as well as pathogenesis-related proteins, will be elaborated as both are very important for understanding the etiology of allergic diseases. Many allergens, such as lipocalins and the pathogenesis-related proteins, are able to bind iron and either deprive or supply iron to immune cells. Thus, a locally induced iron deficiency will result in immune activation and allergic sensitization. However, the same proteins such as the whey protein beta-lactoglobulin can also transport this precious micronutrient to the host immune cells (holoBLG) and hinder their activation, promoting tolerance and protecting against allergy. Since 2019, several clinical trials have also been conducted in allergic subjects using holoBLG as a food for special medical purposes, leading to a reduction in the allergic symptom burden. Supplementation with nutrient-carrying lipocalin proteins can circumvent the mucosal block and nourish selectively immune cells, therefore representing a new dietary and causative approach to compensate for functional iron deficiency in allergy sufferers.
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Affiliation(s)
- Franziska Roth-Walter
- Comparative Medicine, The Interuniversity Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University Vienna, University of Vienna, Vienna, Austria
- Institute of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
- *Correspondence: Franziska Roth-Walter ;
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3
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Bonilla DA, Moreno Y, Petro JL, Forero DA, Vargas-Molina S, Odriozola-Martínez A, Orozco CA, Stout JR, Rawson ES, Kreider RB. A Bioinformatics-Assisted Review on Iron Metabolism and Immune System to Identify Potential Biomarkers of Exercise Stress-Induced Immunosuppression. Biomedicines 2022; 10:724. [PMID: 35327526 PMCID: PMC8945881 DOI: 10.3390/biomedicines10030724] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 03/01/2022] [Accepted: 03/09/2022] [Indexed: 02/01/2023] Open
Abstract
The immune function is closely related to iron (Fe) homeostasis and allostasis. The aim of this bioinformatics-assisted review was twofold; (i) to update the current knowledge of Fe metabolism and its relationship to the immune system, and (ii) to perform a prediction analysis of regulatory network hubs that might serve as potential biomarkers during stress-induced immunosuppression. Several literature and bioinformatics databases/repositories were utilized to review Fe metabolism and complement the molecular description of prioritized proteins. The Search Tool for the Retrieval of Interacting Genes (STRING) was used to build a protein-protein interactions network for subsequent network topology analysis. Importantly, Fe is a sensitive double-edged sword where two extremes of its nutritional status may have harmful effects on innate and adaptive immunity. We identified clearly connected important hubs that belong to two clusters: (i) presentation of peptide antigens to the immune system with the involvement of redox reactions of Fe, heme, and Fe trafficking/transport; and (ii) ubiquitination, endocytosis, and degradation processes of proteins related to Fe metabolism in immune cells (e.g., macrophages). The identified potential biomarkers were in agreement with the current experimental evidence, are included in several immunological/biomarkers databases, and/or are emerging genetic markers for different stressful conditions. Although further validation is warranted, this hybrid method (human-machine collaboration) to extract meaningful biological applications using available data in literature and bioinformatics tools should be highlighted.
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Affiliation(s)
- Diego A. Bonilla
- Research Division, Dynamical Business & Science Society—DBSS International SAS, Bogota 110311, Colombia; (Y.M.); (J.L.P.)
- Research Group in Biochemistry and Molecular Biology, Faculty of Science and Education, Universidad Distrital Francisco José de Caldas, Bogota 110311, Colombia
- Research Group in Physical Activity, Sports and Health Sciences (GICAFS), Universidad de Córdoba, Montería 230002, Colombia
- Sport Genomics Research Group, Department of Genetics, Physical Anthropology and Animal Physiology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain;
| | - Yurany Moreno
- Research Division, Dynamical Business & Science Society—DBSS International SAS, Bogota 110311, Colombia; (Y.M.); (J.L.P.)
- Research Group in Biochemistry and Molecular Biology, Faculty of Science and Education, Universidad Distrital Francisco José de Caldas, Bogota 110311, Colombia
| | - Jorge L. Petro
- Research Division, Dynamical Business & Science Society—DBSS International SAS, Bogota 110311, Colombia; (Y.M.); (J.L.P.)
- Research Group in Physical Activity, Sports and Health Sciences (GICAFS), Universidad de Córdoba, Montería 230002, Colombia
| | - Diego A. Forero
- Health and Sport Sciences Research Group, School of Health and Sport Sciences, Fundación Universitaria del Área Andina, Bogotá 111221, Colombia; (D.A.F.); (C.A.O.)
| | - Salvador Vargas-Molina
- Faculty of Sport Sciences, EADE-University of Wales Trinity Saint David, 29018 Málaga, Spain;
| | - Adrián Odriozola-Martínez
- Sport Genomics Research Group, Department of Genetics, Physical Anthropology and Animal Physiology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain;
- kDNA Genomics, Joxe Mari Korta Research Center, University of the Basque Country UPV/EHU, 20018 Donostia, Spain
| | - Carlos A. Orozco
- Health and Sport Sciences Research Group, School of Health and Sport Sciences, Fundación Universitaria del Área Andina, Bogotá 111221, Colombia; (D.A.F.); (C.A.O.)
| | - Jeffrey R. Stout
- Physiology of Work and Exercise Response (POWER) Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL 32816, USA;
| | - Eric S. Rawson
- Department of Health, Nutrition and Exercise Science, Messiah University, Mechanicsburg, PA 17055, USA;
| | - Richard B. Kreider
- Exercise & Sport Nutrition Laboratory, Human Clinical Research Facility, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843, USA;
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Liu Q, Wu J, Zhang X, Wu X, Zhao Y, Ren J. Iron homeostasis and disorders revisited in the sepsis. Free Radic Biol Med 2021; 165:1-13. [PMID: 33486088 DOI: 10.1016/j.freeradbiomed.2021.01.025] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/31/2020] [Accepted: 01/11/2021] [Indexed: 12/26/2022]
Abstract
Sepsis is a life-threatening condition caused by a dysregulated host-response to inflammation, although it currently lacks a fully elucidated pathobiology. Iron is a crucial trace element that is essential for fundamental processes in both humans and bacteria. During sepsis, iron metabolism is altered, including increased iron transport and uptake into cells and decreased iron export. The intracellular sequestration of iron limits its availability to circulating pathogens, which serves as a conservative strategy against the pathogens. Although iron retention has been showed to have protective protect effects, an increase in labile iron may cause oxidative injury and cell death (e.g., pyroptosis, ferroptosis) as the condition progresses. Moreover, iron disorders are substantial and correlate with the severity of sepsis. This also suggests that iron may be useful as a diagnostic marker for evaluating the severity and predicting the outcome of the disease. Further knowledge about these disorders could help in evaluating how drugs targeting iron homeostasis can be optimally applied to improve the treatment of patients with sepsis. Here, we present a comprehensive review of recent advances in the understanding of iron metabolism, focusing on the regulatory mechanisms and iron-mediated injury in sepsis.
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Affiliation(s)
- Qinjie Liu
- Research Institute of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, PR China.
| | - Jie Wu
- Department of General Surgery, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, 210002, PR China.
| | - Xufei Zhang
- Research Institute of General Surgery, Jinling Hospital, Nanjing Medical University, Nanjing, 210002, PR China.
| | - Xiuwen Wu
- Research Institute of General Surgery, Jinling Hospital, Nanjing, 210002, PR China.
| | - Yun Zhao
- Department of General Surgery, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, 210002, PR China.
| | - Jianan Ren
- Research Institute of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, PR China; Department of General Surgery, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, 210002, PR China; Research Institute of General Surgery, Jinling Hospital, Nanjing Medical University, Nanjing, 210002, PR China.
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5
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Ito H, Kurokawa H, Matsui H. Mitochondrial reactive oxygen species and heme, non-heme iron metabolism. Arch Biochem Biophys 2020; 700:108695. [PMID: 33232715 DOI: 10.1016/j.abb.2020.108695] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/13/2022]
Abstract
Mitochondria are one of the most important organelles for eukaryotes, including humans, to produce energy. In the energy-producing process, mitochondria constantly generate reactive oxygen species as a by-product of electrons leaking out from the electron transport chain react with oxygen. The active oxygen, in turn, plays pivotal roles in mediating several signalings, including those that are implicated in the development of some diseases such as neurodegenerative disease, cardiovascular disease, and carcinogenesis. This signaling, derived from mitochondrial reactive oxygen species, also affects intracellular iron homeostasis by regulating the expression of transporters. Heme iron is incorporated into cells through HCP1, and non-heme iron is transported by DMT1 in absorptive cells. Intracellular iron is exported by ferroportin and bound with transferrin. In most types of cell including erythrocyte, transferrin-bound iron is incorporated through transferrin-transferrin receptor system. We previously reported that the expression of HCP1 and DMT1 was upregulated in cancer cells and that overexpression of manganese superoxide dismutase, which is a mitochondrial-specific superoxide dismutase, downregulated the expression. These findings indicate that mitochondrial reactive oxygen species is associated with iron-related oxidative reactions. Recently, a mitochondria-specific iron transporter, mitoferrin, was identified, and the relationships among mitochondria, iron transportation, and diseases have been increasingly clarified.
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Affiliation(s)
- Hiromu Ito
- Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan; Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan
| | - Hiromi Kurokawa
- Algae Biomass research and development, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Hirofumi Matsui
- Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan; Algae Biomass research and development, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
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6
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Heme oxygenase 1 protects human colonocytes against ROS formation, oxidative DNA damage and cytotoxicity induced by heme iron, but not inorganic iron. Cell Death Dis 2020; 11:787. [PMID: 32968051 PMCID: PMC7511955 DOI: 10.1038/s41419-020-02950-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 08/20/2020] [Accepted: 08/27/2020] [Indexed: 12/14/2022]
Abstract
The consumption of red meat is probably carcinogenic to humans and is associated with an increased risk to develop colorectal cancer (CRC). Red meat contains high amounts of heme iron, which is thought to play a causal role in tumor formation. In this study, we investigated the genotoxic and cytotoxic effects of heme iron (i.e., hemin) versus inorganic iron in human colonic epithelial cells (HCEC), human CRC cell lines and murine intestinal organoids. Hemin catalyzed the formation of reactive oxygen species (ROS) and induced oxidative DNA damage as well as DNA strand breaks in both HCEC and CRC cells. In contrast, inorganic iron hardly affected ROS levels and only slightly increased DNA damage. Hemin, but not inorganic iron, caused cell death and reduced cell viability. This occurred preferentially in non-malignant HCEC, which was corroborated in intestinal organoids. Both hemin and inorganic iron were taken up into HCEC and CRC cells, however with differential kinetics and efficiency. Hemin caused stabilization and nuclear translocation of Nrf2, which induced heme oxygenase-1 (HO-1) and ferritin heavy chain (FtH). This was not observed after inorganic iron treatment. Chemical inhibition or genetic knockdown of HO-1 potentiated hemin-triggered ROS generation and oxidative DNA damage preferentially in HCEC. Furthermore, HO-1 abrogation strongly augmented the cytotoxic effects of hemin in HCEC, revealing its pivotal function in colonocytes and highlighting the toxicity of free intracellular heme iron. Taken together, this study demonstrated that hemin, but not inorganic iron, induces ROS and DNA damage, resulting in a preferential cytotoxicity in non-malignant intestinal epithelial cells. Importantly, HO-1 conferred protection against the detrimental effects of hemin.
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7
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Grzeszczak K, Kwiatkowski S, Kosik-Bogacka D. The Role of Fe, Zn, and Cu in Pregnancy. Biomolecules 2020; 10:E1176. [PMID: 32806787 PMCID: PMC7463674 DOI: 10.3390/biom10081176] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 08/05/2020] [Accepted: 08/05/2020] [Indexed: 12/15/2022] Open
Abstract
Iron (Fe), copper (Cu), and zinc (Zn) are microelements essential for the proper functioning of living organisms. These elements participatein many processes, including cellular metabolism and antioxidant and anti-inflammatory defenses, and also influence enzyme activity, regulate gene expression, and take part in protein synthesis. Fe, Cu, and Zn have a significant impact on the health of pregnant women and in the development of the fetus, as well as on the health of the newborn. A proper concentration of these elements in the body of women during pregnancy reduces the risk of complications such as anemia, induced hypertension, low birth weight, preeclampsia, and postnatal complications. The interactions between Fe, Cu, and Zn influence their availability due to their similar physicochemical properties. This most often occurs during intestinal absorption, where metal ions compete for binding sites with transport compounds. Additionally, the relationships between these ions have a great influence on the course of reactions in the tissues, as well as on their excretion, which can be stimulated or delayed. This review aims to summarize reports on the influence of Fe, Cu, and Zn on the course of single and multiple pregnancies, and to discuss the interdependencies and mechanisms occurring between Fe, Cu, and Zn.
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Affiliation(s)
- Konrad Grzeszczak
- Department of Biology and Medical Parasitology, Pomeranian Medical University in Szczecin, Powstańców Wielkopolskich 72, 70-111 Szczecin, Poland;
| | - Sebastian Kwiatkowski
- Department of Obstetrics and Gynecology, Pomeranian Medical University in Szczecin, Powstańców Wielkopolskich 72, 70-111 Szczecin, Poland;
| | - Danuta Kosik-Bogacka
- Independent Laboratory of Pharmaceutical Botany, Pomeranian Medical University in Szczecin, Powstańców Wielkopolskich 72, 70-111 Szczecin, Poland
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8
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Chondroitin sulfate and its nanocomposites with protamine or chitosan stabilize and deliver available nanosized iron. Int J Biol Macromol 2020; 150:501-508. [DOI: 10.1016/j.ijbiomac.2020.02.103] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 02/09/2020] [Accepted: 02/10/2020] [Indexed: 12/19/2022]
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9
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Seiwert N, Heylmann D, Hasselwander S, Fahrer J. Mechanism of colorectal carcinogenesis triggered by heme iron from red meat. Biochim Biophys Acta Rev Cancer 2019; 1873:188334. [PMID: 31783067 DOI: 10.1016/j.bbcan.2019.188334] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/25/2019] [Accepted: 11/25/2019] [Indexed: 02/07/2023]
Abstract
Colorectal cancer (CRC) is one of the major tumor entities worldwide, with an increasing incidence in younger people. CRC formation is causally linked to various genetic, life-style and dietary risk factors. Among the ladder, the consumption of red meat has emerged as important risk factor contributing to CRC. A large body of evidence shows that heme iron is the critical component of red meat, which promotes colorectal carcinogenesis. In this review, we describe the uptake and cellular fate of both heme and inorganic iron in intestinal epithelial cells. Next, an overview on the DNA damaging properties of heme iron is provided, highlighting the DNA adducts relevant for CRC etiology. Moreover, heme triggered mechanisms leading to colonic hyperproliferation are presented, which are intimately linked to changes in the intestinal microbiota induced by heme. A special focus was set on the impact of heme iron on innate and adaptive immune cells, which could be relevant in the context of CRC. Finally, we recapitulate in vivo studies providing evidence for the tumor-promoting potential of dietary heme iron. Altogether, heme iron affects numerous key pathways involved in the pathogenesis of CRC.
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Affiliation(s)
- Nina Seiwert
- Department of Toxicology, University Medical Center Mainz, 55131 Mainz, Germany; Rudolf Buchheim Institute of Pharmacology, Justus Liebig University Giessen, 35392 Giessen, Germany; Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Daniel Heylmann
- Rudolf Buchheim Institute of Pharmacology, Justus Liebig University Giessen, 35392 Giessen, Germany
| | | | - Jörg Fahrer
- Department of Toxicology, University Medical Center Mainz, 55131 Mainz, Germany; Rudolf Buchheim Institute of Pharmacology, Justus Liebig University Giessen, 35392 Giessen, Germany; Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany.
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10
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Zhu Y, Tong L, Nie K, Wiwatanaratanabutr I, Sun P, Li Q, Yu X, Wu P, Wu T, Yu C, Liu Q, Bian Z, Wang P, Cheng G. Host serum iron modulates dengue virus acquisition by mosquitoes. Nat Microbiol 2019; 4:2405-2415. [DOI: 10.1038/s41564-019-0555-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 08/06/2019] [Indexed: 12/14/2022]
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Rafikova O, Williams ER, McBride ML, Zemskova M, Srivastava A, Nair V, Desai AA, Langlais PR, Zemskov E, Simon M, Mandarino LJ, Rafikov R. Hemolysis-induced Lung Vascular Leakage Contributes to the Development of Pulmonary Hypertension. Am J Respir Cell Mol Biol 2019; 59:334-345. [PMID: 29652520 DOI: 10.1165/rcmb.2017-0308oc] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Although hemolytic anemia-associated pulmonary hypertension (PH) and pulmonary arterial hypertension (PAH) are more common than the prevalence of idiopathic PAH alone, the role of hemolysis in the development of PAH is poorly characterized. We hypothesized that hemolysis independently contributes to PAH pathogenesis via endothelial barrier dysfunction with resulting perivascular edema and inflammation. Plasma samples from patients with and without PAH (both confirmed by right heart catheterization) were used to measure free hemoglobin (Hb) and its correlation with PAH severity. A sugen (50 mg/kg)/hypoxia (3 wk)/normoxia (2 wk) rat model was used to elucidate the role of free Hb/heme pathways in PAH. Human lung microvascular endothelial cells were used to study heme-mediated endothelial barrier effects. Our data indicate that patients with PAH have increased levels of free Hb in plasma that correlate with PAH severity. There is also a significant accumulation of free Hb and depletion of haptoglobin in the rat model. In rats, perivascular edema was observed at early time points concomitant with increased infiltration of inflammatory cells. Heme-induced endothelial permeability in human lung microvascular endothelial cells involved activation of the p38/HSP27 pathway. Indeed, the rat model also exhibited increased activation of p38/HSP27 during the initial phase of PH. Surprisingly, despite the increased levels of hemolysis and heme-mediated signaling, there was no heme oxygenase-1 activation. This can be explained by observed destabilization of HIF-1a during the first 2 weeks of PH regardless of hypoxic conditions. Our data suggest that hemolysis may play a significant role in PAH pathobiology.
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Affiliation(s)
- Olga Rafikova
- 1 Department of Medicine, Division of Endocrinology, and
| | | | | | | | | | - Vineet Nair
- 2 Division of Cardiology, Sarver Heart Center, Department of Medicine, University of Arizona, Tucson, Arizona; and
| | - Ankit A Desai
- 2 Division of Cardiology, Sarver Heart Center, Department of Medicine, University of Arizona, Tucson, Arizona; and
| | | | - Evgeny Zemskov
- 3 Department of Medicine, Division of Translational and Regenerative Medicine, University of Arizona College of Medicine, Tucson, Arizona
| | - Marc Simon
- 4 Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
| | | | - Ruslan Rafikov
- 1 Department of Medicine, Division of Endocrinology, and
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Nairz M, Dichtl S, Schroll A, Haschka D, Tymoszuk P, Theurl I, Weiss G. Iron and innate antimicrobial immunity-Depriving the pathogen, defending the host. J Trace Elem Med Biol 2018; 48:118-133. [PMID: 29773170 DOI: 10.1016/j.jtemb.2018.03.007] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 02/25/2018] [Accepted: 03/06/2018] [Indexed: 02/08/2023]
Abstract
The acute-phase response is triggered by the presence of infectious agents and danger signals which indicate hazards for the integrity of the mammalian body. One central feature of this response is the sequestration of iron into storage compartments including macrophages. This limits the availability of this essential nutrient for circulating pathogens, a host defence strategy known as 'nutritional immunity'. Iron metabolism and the immune response are intimately linked. In infections, the availability of iron affects both the efficacy of antimicrobial immune pathways and pathogen proliferation. However, host strategies to withhold iron from microbes vary according to the localization of pathogens: Infections with extracellular bacteria such as Staphylococcus aureus, Streptococcus, Klebsiella or Yersinia stimulate the expression of the iron-regulatory hormone hepcidin which targets the cellular iron-exporter ferroportin-1 causing its internalization and blockade of iron egress from absorptive enterocytes in the duodenum and iron-recycling macrophages. This mechanism disrupts both routes of iron delivery to the circulation, contributes to iron sequestration in the mononuclear phagocyte system and mediates the hypoferraemia of the acute phase response subsequently resulting in the development of anaemia of inflammation. When intracellular microbes are present, other strategies of microbial iron withdrawal are needed. For instance, in macrophages harbouring intracellular pathogens such as Chlamydia, Mycobacterium tuberculosis, Listeria monocytogenes or Salmonella Typhimurium, ferroportin-1-mediated iron export is turned on for the removal of iron from infected cells. This also leads to reduced iron availability for intra-macrophage pathogens which inhibits their growth and in parallel strengthens anti-microbial effector pathways of macrophages including the formation of inducible nitric oxide synthase and tumour necrosis factor. Iron plays a key role in infectious diseases both as modulator of the innate immune response and as nutrient for microbes. We need to gain a more comprehensive understanding of how the body can differentially respond to infection by extra- or intracellular pathogens. This knowledge may allow us to modulate mammalian iron homeostasis pharmaceutically and to target iron-acquisition systems of pathogens, thus enabling us to treat infections with novel strategies that act independent of established antimicrobials.
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Affiliation(s)
- Manfred Nairz
- Department of Internal Medicine II, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria.
| | - Stefanie Dichtl
- Department of Internal Medicine II, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Andrea Schroll
- Department of Internal Medicine II, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - David Haschka
- Department of Internal Medicine II, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Piotr Tymoszuk
- Department of Internal Medicine II, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Igor Theurl
- Department of Internal Medicine II, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Günter Weiss
- Department of Internal Medicine II, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
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Bonaccorsi di Patti MC, Cutone A, Polticelli F, Rosa L, Lepanto MS, Valenti P, Musci G. The ferroportin-ceruloplasmin system and the mammalian iron homeostasis machine: regulatory pathways and the role of lactoferrin. Biometals 2018; 31:399-414. [PMID: 29453656 DOI: 10.1007/s10534-018-0087-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 02/14/2018] [Indexed: 02/08/2023]
Abstract
In the last 20 years, several new genes and proteins involved in iron metabolism in eukaryotes, particularly related to pathological states both in animal models and in humans have been identified, and we are now starting to unveil at the molecular level the mechanisms of iron absorption, the regulation of iron transport and the homeostatic balancing processes. In this review, we will briefly outline the general scheme of iron metabolism in humans and then focus our attention on the cellular iron export system formed by the permease ferroportin and the ferroxidase ceruloplasmin. We will finally summarize data on the role of the iron binding protein lactoferrin on the regulation of the ferroportin/ceruloplasmin couple and of other proteins involved in iron homeostasis in inflamed human macrophages.
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Affiliation(s)
| | - Antimo Cutone
- Department of Biosciences and Territory, University of Molise, C.da Fonte Lappone, 86090, Pesche, IS, Italy
| | - Fabio Polticelli
- Department of Sciences, University Roma Tre, Rome, Italy.,National Institute of Nuclear Physics, Roma Tre Section, Rome, Italy
| | - Luigi Rosa
- Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy
| | | | - Piera Valenti
- Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy
| | - Giovanni Musci
- Department of Biosciences and Territory, University of Molise, C.da Fonte Lappone, 86090, Pesche, IS, Italy.
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Roth-Walter F, Pacios LF, Bianchini R, Jensen-Jarolim E. Linking iron-deficiency with allergy: role of molecular allergens and the microbiome. Metallomics 2017; 9:1676-1692. [PMID: 29120476 DOI: 10.1039/c7mt00241f] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Atopic individuals tend to develop a Th2 dominant immune response, resulting in hyperresponsiveness to harmless antigens, termed allergens. In the last decade, epidemiological studies have emerged that connected allergy with a deficient iron-status. Immune activation under iron-deficient conditions results in the expansion of Th2-, but not Th1 cells, can induce class-switching in B-cells and hampers the proper activation of M2, but not M1 macrophages. Moreover, many allergens, in particular with the lipocalin and lipocalin-like folds, seem to be capable of binding iron indirectly via siderophores harboring catechol moieties. The resulting locally restricted iron-deficiency may then lead during immune activation to the generation of Th2-cells and thus prepare for allergic sensitization. Moreover, iron-chelators seem to also influence clinical reactivity: mast cells accumulate iron before degranulation and seem to respond differently depending on the type of the encountered siderophore. Whereas deferoxamine triggers degranulation of connective tissue-type mast cells, catechol-based siderophores reduce activation and degranulation and improve clinical symptoms. Considering the complex interplay of iron, siderophores and immune molecules, it remains to be determined whether iron-deficiencies are the cause or the result of allergy.
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Affiliation(s)
- Franziska Roth-Walter
- Department of Comparative Medicine, at the Interuniversity Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna, Vienna, Austria.
| | - Luis F Pacios
- Centro de Biotecnología y Genómica de Plantas (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo-UPM, 28223 Pozuelo de Alarcón, Madrid, Spain
| | - Rodolfo Bianchini
- Department of Comparative Medicine, at the Interuniversity Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna, Vienna, Austria.
| | - Erika Jensen-Jarolim
- Department of Comparative Medicine, at the Interuniversity Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna, Vienna, Austria. and Institute of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
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15
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Weinborn V, Valenzuela C, Olivares M, Arredondo M, Weill R, Pizarro F. Prebiotics increase heme iron bioavailability and do not affect non-heme iron bioavailability in humans. Food Funct 2017; 8:1994-1999. [PMID: 28485415 DOI: 10.1039/c6fo01833e] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The aim of this study was to establish the effect of a prebiotic mix on heme and non-heme iron (Fe) bioavailability in humans. To this purpose, twenty-four healthy women were randomized into one of two study groups. One group ate one yogurt per day for 12 days with a prebiotic mix (prebiotic group) and the other group received the same yogurt but without the prebiotic mix (control group). Before and after the intake period, the subjects participated in Fe absorption studies. These studies used 55Fe and 59Fe radioactive isotopes as markers of heme Fe and non-heme Fe, respectively, and Fe absorption was measured by the incorporation of radioactive Fe into erythrocytes. The results showed that there were no significant differences in heme and non-heme Fe bioavailability in the control group. Heme Fe bioavailability of the prebiotic group increased significantly by 56% post-prebiotic intake. There were no significant differences in non-heme Fe bioavailability in this group. We concluded that daily consumption of a prebiotic mix increases heme Fe bioavailability and does not affect non-heme iron bioavailability.
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Affiliation(s)
- Valerie Weinborn
- Department of Food Science and Technology, University of California, Davis, 1 Shields Avenue, Davis, CA, 95616, USA
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16
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Dietary hemoglobin rescues young piglets from severe iron deficiency anemia: Duodenal expression profile of genes involved in heme iron absorption. PLoS One 2017; 12:e0181117. [PMID: 28704474 PMCID: PMC5514692 DOI: 10.1371/journal.pone.0181117] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/25/2017] [Indexed: 12/22/2022] Open
Abstract
Heme is an efficient source of iron in the diet, and heme preparations are used to prevent and cure iron deficiency anemia in humans and animals. However, the molecular mechanisms responsible for heme absorption remain only partially characterized. Here, we employed young iron-deficient piglets as a convenient animal model to determine the efficacy of oral heme iron supplementation and investigate the pathways of heme iron absorption. The use of bovine hemoglobin as a dietary source of heme iron was found to efficiently counteract the development of iron deficiency anemia in piglets, although it did not fully rebalance their iron status. Our results revealed a concerted increase in the expression of genes responsible for apical and basolateral heme transport in the duodenum of piglets fed a heme-enriched diet. In these animals the catalytic activity of heme oxygenase 1 contributed to the release of elemental iron from the protoporphyrin ring of heme within enterocytes, which may then be transported by the strongly expressed ferroportin across the basolateral membrane to the circulation. We hypothesize that the well-recognized high bioavailability of heme iron may depend on a split pathway mediating the transport of heme-derived elemental iron and intact heme from the interior of duodenal enterocytes to the bloodstream.
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17
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Best CM, Pressman EK, Cao C, Cooper E, Guillet R, Yost OL, Galati J, Kent TR, O'Brien KO. Maternal iron status during pregnancy compared with neonatal iron status better predicts placental iron transporter expression in humans. FASEB J 2016; 30:3541-3550. [PMID: 27402672 PMCID: PMC5024693 DOI: 10.1096/fj.201600069r] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 06/28/2016] [Indexed: 01/06/2023]
Abstract
The placenta richly expresses nonheme and heme Fe transport proteins. To address the impact of maternal and neonatal Fe status and hepcidin on the regulation of these proteins, mRNA expression and protein abundance of nonheme and heme Fe transport proteins were evaluated in placental tissue from 154 adolescents. Regression analyses found maternal Fe status was significantly associated with multiple placental nonheme and heme transporters, whereas neonatal Fe status was related to only 3 heme transporters. Across statistical analyses, maternal Fe status was consistently associated with the placental nonheme Fe importer transferrin receptor 1 (TfR1). Protein abundance of TfR1 was related to midgestation maternal serum ferritin (SF) (β = -0.32; P = 0.005) and serum TfR (β = 0.25; P = 0.024). Protein abundance of the heme importer, proton-coupled folate transporter, was related to neonatal SF (β = 0.30; P = 0.016) and serum TfR (β = -0.46; P < 0.0001). Neonatal SF was also related to mRNA expression of the heme exporter feline leukemia virus subgroup C receptor 1 (β = -0.30; P = 0.004). In summary, maternal Fe insufficiency during pregnancy predicts increased expression of the placental nonheme Fe transporter TfR1. Associations between placental heme Fe transporters and neonatal Fe status require further study.-Best, C. M., Pressman, E. K., Cao, C., Cooper, E., Guillet, R., Yost, O. L., Galati, J., Kent, T. R., O'Brien, K. O. Maternal iron status during pregnancy compared with neonatal iron status better predicts placental iron transporter expression in humans.
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Affiliation(s)
- Cora M Best
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA
| | - Eva K Pressman
- University of Rochester School of Medicine and Dentistry, Rochester, New York, USA; and
| | - Chang Cao
- Department of Pathology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Elizabeth Cooper
- University of Rochester School of Medicine and Dentistry, Rochester, New York, USA; and
| | - Ronnie Guillet
- University of Rochester School of Medicine and Dentistry, Rochester, New York, USA; and
| | - Olivia L Yost
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA
| | - Jonathan Galati
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA
| | - Tera R Kent
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA
| | - Kimberly O O'Brien
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA;
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18
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A holistic view of cancer bioenergetics: mitochondrial function and respiration play fundamental roles in the development and progression of diverse tumors. Clin Transl Med 2016; 5:3. [PMID: 26812134 PMCID: PMC4728164 DOI: 10.1186/s40169-016-0082-9] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 01/11/2016] [Indexed: 02/01/2023] Open
Abstract
Since Otto Warburg made the first observation that tumor cells exhibit altered metabolism and bioenergetics in the 1920s, many scientists have tried to further the understanding of tumor bioenergetics. Particularly, in the past decade, the application of the state-of the-art metabolomics and genomics technologies has revealed the remarkable plasticity of tumor metabolism and bioenergetics. Firstly, a wide array of tumor cells have been shown to be able to use not only glucose, but also glutamine for generating cellular energy, reducing power, and metabolic building blocks for biosynthesis. Secondly, many types of cancer cells generate most of their cellular energy via mitochondrial respiration and oxidative phosphorylation. Glutamine is the preferred substrate for oxidative phosphorylation in tumor cells. Thirdly, tumor cells exhibit remarkable versatility in using bioenergetics substrates. Notably, tumor cells can use metabolic substrates donated by stromal cells for cellular energy generation via oxidative phosphorylation. Further, it has been shown that mitochondrial transfer is a critical mechanism for tumor cells with defective mitochondria to restore oxidative phosphorylation. The restoration is necessary for tumor cells to gain tumorigenic and metastatic potential. It is also worth noting that heme is essential for the biogenesis and proper functioning of mitochondrial respiratory chain complexes. Hence, it is not surprising that recent experimental data showed that heme flux and function are elevated in non-small cell lung cancer (NSCLC) cells and that elevated heme function promotes intensified oxygen consumption, thereby fueling tumor cell proliferation and function. Finally, emerging evidence increasingly suggests that clonal evolution and tumor genetic heterogeneity contribute to bioenergetic versatility of tumor cells, as well as tumor recurrence and drug resistance. Although mutations are found only in several metabolic enzymes in tumors, diverse mutations in signaling pathways and networks can cause changes in the expression and activity of metabolic enzymes, which likely enable tumor cells to gain their bioenergetic versatility. A better understanding of tumor bioenergetics should provide a more holistic approach to investigate cancer biology and therapeutics. This review therefore attempts to comprehensively consider and summarize the experimental data supporting our latest view of cancer bioenergetics.
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Ali S. Questions and answers. THE EGYPTIAN JOURNAL OF INTERNAL MEDICINE 2015. [DOI: 10.4103/1110-7782.159479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Abstract
The properties of intestinal folate absorption were documented decades ago. However, it was only recently that the proton-coupled folate transporter (PCFT) was identified and its critical role in folate transport across the apical brush-border membrane of the proximal small intestine established by the loss-of-function mutations identified in the PCFT gene in subjects with hereditary folate malabsorption and, more recently, by the Pcft-null mouse. This article reviews the current understanding of the properties of PCFT-mediated transport and how they differ from those of the reduced folate carrier. Other processes that contribute to the transport of folates across the enterocyte, along with the contribution of the enterohepatic circulation, are considered. Important unresolved issues are addressed, including the mechanism of intestinal folate absorption in the absence of PCFT and regulation of PCFT gene expression. The impact of a variety of ions, organic molecules, and drugs on PCFT-mediated folate transport is described.
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Affiliation(s)
- Michele Visentin
- Departments of Molecular Pharmacology and Medicine, Albert Einstein College of Medicine, Bronx, New York 10461; , , ,
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21
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Wu H, Zhu S, Zeng M, Liu Z, Dong S, Zhao Y, Huang H, Lo YM. Enhancement of non-heme iron absorption by anchovy (Engraulis japonicus) muscle protein hydrolysate involves a nanoparticle-mediated mechanism. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:8632-8639. [PMID: 25074419 DOI: 10.1021/jf5018719] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The mechanisms by which meat enhances human absorption of non-heme iron remain unknown. Recently, anchovy (Engraulis japonicus) muscle protein hydrolysate (AMPH) was found to mediate the formation of nanosized ferric hydrolysis products in vitro. The current paper evaluates the effects of AMPH on the bioavailability and the intestinal speciation of non-heme iron in rats, followed by an investigation of cellular uptake pathways of in vitro-formed AMPH-stabilized nanosized ferric hydrolysis products (ANPs) by polarized human intestinal epithelial (Caco-2) cells. The hemoglobin regeneration efficiencies in anemic rats followed the order ferric citrate (9.79 ± 2.02%) < commercial bare α-Fe2O3 nanoparticles (16.37 ± 6.65%) < mixture of ferric citrate and AMPH (40.33 ± 6.36%) ≈ ferrous sulfate (40.88 ± 7.67%) < ANPs (56.25 ± 11.35%). Percentage contents of intestinal low-molecular-weight iron in the groups of FC+AMPH, FeSO4, and ANPs were significantly lower than the corresponding hemoglobin regeneration efficiencies (P < 0.05), providing strong evidence for the involvement of nanosized iron in intestinal iron absorption from FC+AMPH, FeSO4, and ANPs. Calcein-fluorescence measurements of the labile iron pool of polarized Caco-2 cells revealed the involvement of both divalent transporter 1 and endocytosis in apical uptake of ANPs, with endocytosis dominating at acidic extracellular pH. Overall, AMPH enhancement of non-heme iron absorption involves a nanoparticle-mediated mechanism.
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Affiliation(s)
- Haohao Wu
- College of Food Science and Engineering, Ocean University of China , 5 Yushan Road, Qingdao, Shandong Province 266003, China
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22
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Ito H, Matsui H, Tamura M, Majima HJ, Indo HP, Hyodo I. Mitochondrial reactive oxygen species accelerate the expression of heme carrier protein 1 and enhance photodynamic cancer therapy effect. J Clin Biochem Nutr 2014; 55:67-71. [PMID: 25120282 PMCID: PMC4078070 DOI: 10.3164/jcbn.14-27] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 02/27/2014] [Indexed: 12/26/2022] Open
Abstract
Photodynamic therapy using hematoporphyrin and its derivatives is clinically useful for cancer treatments. It has been reported that cancer cells incorporate hematoporphyrin and its derivatives via heme carrier protein 1, which is a proton-coupled folate transporter. However, the mechanism of this protein expression has not been elucidated. In general, the concentration of reactive oxygen species in cancer cells is higher than that in normal cells. We previously reported that reactive oxygen species from mitochondria involved in the expression of peptide transporter 1 and accelerate the uptake of 5-aminolevulinic acid, which is a precursor of protoporphyrin IX. We suggested mitochondrial reactive oxygen species also regulated the expression of heme carrier protein 1. In this study, we used a rat gastric mucosal cell line RGM1 and its cancer-like mutated cell line RGK1. We clarified the expression of heme carrier protein 1 increased in cancer cells and it decreased in manganese superoxide dismutase expressed cancer cells. In addition, the uptake level of hematoporphyrin and photodynamic therapeutic effect were also decreased in manganese superoxide dismutase expressed cancer cells in comparison with cancer cells. Thus, we concluded that mitochondrial reactive oxygen species regulated heme carrier protein 1 expression and photodynamic therapeutic effect.
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Affiliation(s)
- Hiromu Ito
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nohdai, Tsukuba, Ibaraki 305-8575, Japan
| | - Hirofumi Matsui
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nohdai, Tsukuba, Ibaraki 305-8575, Japan
| | - Masato Tamura
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nohdai, Tsukuba, Ibaraki 305-8575, Japan
| | - Hideyuki J Majima
- Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1, Sakuragaoka, Kagoshima, Japan
| | - Hiroko P Indo
- Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1, Sakuragaoka, Kagoshima, Japan
| | - Ichinosuke Hyodo
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nohdai, Tsukuba, Ibaraki 305-8575, Japan
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Dutra FF, Bozza MT. Heme on innate immunity and inflammation. Front Pharmacol 2014; 5:115. [PMID: 24904418 PMCID: PMC4035012 DOI: 10.3389/fphar.2014.00115] [Citation(s) in RCA: 225] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Accepted: 04/29/2014] [Indexed: 12/30/2022] Open
Abstract
Heme is an essential molecule expressed ubiquitously all through our tissues. Heme plays major functions in cellular physiology and metabolism as the prosthetic group of diverse proteins. Once released from cells and from hemeproteins free heme causes oxidative damage and inflammation, thus acting as a prototypic damage-associated molecular pattern. In this context, free heme is a critical component of the pathological process of sterile and infectious hemolytic conditions including malaria, hemolytic anemias, ischemia-reperfusion, and hemorrhage. The plasma scavenger proteins hemopexin and albumin reduce heme toxicity and are responsible for transporting free heme to intracellular compartments where it is catabolized by heme-oxygenase enzymes. Upon hemolysis or severe cellular damage the serum capacity to scavenge heme may saturate and increase free heme to sufficient amounts to cause tissue damage in various organs. The mechanism by which heme causes reactive oxygen generation, activation of cells of the innate immune system and cell death are not fully understood. Although heme can directly promote lipid peroxidation by its iron atom, heme can also induce reactive oxygen species generation and production of inflammatory mediators through the activation of selective signaling pathways. Heme activates innate immune cells such as macrophages and neutrophils through activation of innate immune receptors. The importance of these events has been demonstrated in infectious and non-infectious diseases models. In this review, we will discuss the mechanisms behind heme-induced cytotoxicity and inflammation and the consequences of these events on different tissues and diseases.
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Affiliation(s)
- Fabianno F. Dutra
- Laboratório de Inflamação e Imunidade, Departamento de Imunologia, Instituto de Microbiologia, Universidade Federal do Rio de JaneiroRio de Janeiro, Brazil
| | - Marcelo T. Bozza
- Laboratório de Inflamação e Imunidade, Departamento de Imunologia, Instituto de Microbiologia, Universidade Federal do Rio de JaneiroRio de Janeiro, Brazil
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Kissei M, Itoh T, Narawa T. Effect of epigallocatechin gallate on drug transport mediated by the proton-coupled folate transporter. Drug Metab Pharmacokinet 2014; 29:367-72. [PMID: 24695276 DOI: 10.2133/dmpk.dmpk-14-rg-015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Folic acid (FA) is a water-soluble vitamin, and orally ingested FA is absorbed from the small intestine by the proton-coupled folate transporter (PCFT). In the present study, we investigated whether epigallocatechin gallate (EGCG), one of the tea catechins, affects the transport of FA by PCFT. EGCG inhibited the uptake of FA into Caco-2 cells and human PCFT-expressing HEK293 cells (PCFT-HEK293 cells). The initial rate of uptake of FA into PCFT-HEK293 cells followed Michaelis-Menten kinetics (K(m) = 1.9 µM). Dixon plots revealed that PCFT-mediated FA uptake was competitively inhibited by EGCG (K(i) ≒ 9 µM). The uptake of the PCFT substrate methotrexate (MTX) was competitively inhibited by EGCG as well (K(i) ≒ 15 µM). In conclusion, it is suggested that when FA or MTX is ingested with tea, it is likely that the intestinal absorption of these compounds by PCFT is inhibited, which could result in insufficient efficacy.
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25
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Heme, an essential nutrient from dietary proteins, critically impacts diverse physiological and pathological processes. Nutrients 2014; 6:1080-102. [PMID: 24633395 PMCID: PMC3967179 DOI: 10.3390/nu6031080] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 02/14/2014] [Accepted: 02/19/2014] [Indexed: 12/11/2022] Open
Abstract
Heme constitutes 95% of functional iron in the human body, as well as two-thirds of the average person’s iron intake in developed countries. Hence, a wide range of epidemiological studies have focused on examining the association of dietary heme intake, mainly from red meat, with the risks of common diseases. High heme intake is associated with increased risk of several cancers, including colorectal cancer, pancreatic cancer and lung cancer. Likewise, the evidence for increased risks of type-2 diabetes and coronary heart disease associated with high heme intake is compelling. Furthermore, recent comparative metabolic and molecular studies of lung cancer cells showed that cancer cells require increased intracellular heme biosynthesis and uptake to meet the increased demand for oxygen-utilizing hemoproteins. Increased levels of hemoproteins in turn lead to intensified oxygen consumption and cellular energy generation, thereby fueling cancer cell progression. Together, both epidemiological and molecular studies support the idea that heme positively impacts cancer progression. However, it is also worth noting that heme deficiency can cause serious diseases in humans, such as anemia, porphyrias, and Alzheimer’s disease. This review attempts to summarize the latest literature in understanding the role of dietary heme intake and heme function in diverse diseases.
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26
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Shah YM, Xie L. Hypoxia-inducible factors link iron homeostasis and erythropoiesis. Gastroenterology 2014; 146:630-42. [PMID: 24389303 PMCID: PMC3943938 DOI: 10.1053/j.gastro.2013.12.031] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/06/2013] [Accepted: 12/10/2013] [Indexed: 12/15/2022]
Abstract
Iron is required for efficient oxygen transport, and hypoxia signaling links erythropoiesis with iron homeostasis. Hypoxia induces a highly conserved signaling pathway in cells under conditions of low levels of O2. One component of this pathway, hypoxia-inducible factor (HIF), is a transcription factor that is highly active in hypoxic cells. The first HIF target gene characterized was EPO, which encodes erythropoietin-a glycoprotein hormone that controls erythropoiesis. In the past decade, there have been fundamental advances in our understanding of how hypoxia regulates iron levels to support erythropoiesis and maintain systemic iron homeostasis. We review the cell type-specific effects of hypoxia and HIFs in adaptive response to changes in oxygen and iron availability as well as potential uses of HIF modulators for patients with iron-related disorders.
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Affiliation(s)
- Yatrik M. Shah
- Department of Molecular & Integrative Physiology, Division of Gastroenterology, University of Michigan, Ann Arbor, Michigan,Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, Michigan, To whom correspondence should be addressed. Tel: +1 734 6150567; Fax: +1 734 9368813;
| | - Liwei Xie
- Department of Molecular & Integrative Physiology, Division of Gastroenterology, University of Michigan, Ann Arbor, Michigan
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27
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Multi-copper oxidases and human iron metabolism. Nutrients 2013; 5:2289-313. [PMID: 23807651 PMCID: PMC3738974 DOI: 10.3390/nu5072289] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 05/29/2013] [Accepted: 06/06/2013] [Indexed: 01/13/2023] Open
Abstract
Multi-copper oxidases (MCOs) are a small group of enzymes that oxidize their substrate with the concomitant reduction of dioxygen to two water molecules. Generally, multi-copper oxidases are promiscuous with regards to their reducing substrates and are capable of performing various functions in different species. To date, three multi-copper oxidases have been detected in humans—ceruloplasmin, hephaestin and zyklopen. Each of these enzymes has a high specificity towards iron with the resulting ferroxidase activity being associated with ferroportin, the only known iron exporter protein in humans. Ferroportin exports iron as Fe2+, but transferrin, the major iron transporter protein of blood, can bind only Fe3+ effectively. Iron oxidation in enterocytes is mediated mainly by hephaestin thus allowing dietary iron to enter the bloodstream. Zyklopen is involved in iron efflux from placental trophoblasts during iron transfer from mother to fetus. Release of iron from the liver relies on ferroportin and the ferroxidase activity of ceruloplasmin which is found in blood in a soluble form. Ceruloplasmin, hephaestin and zyklopen show distinctive expression patterns and have unique mechanisms for regulating their expression. These features of human multi-copper ferroxidases can serve as a basis for the precise control of iron efflux in different tissues. In this manuscript, we review the biochemical and biological properties of the three human MCOs and discuss their potential roles in human iron homeostasis.
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28
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Hooda J, Cadinu D, Alam MM, Shah A, Cao TM, Sullivan LA, Brekken R, Zhang L. Enhanced heme function and mitochondrial respiration promote the progression of lung cancer cells. PLoS One 2013; 8:e63402. [PMID: 23704904 PMCID: PMC3660535 DOI: 10.1371/journal.pone.0063402] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 03/31/2013] [Indexed: 11/18/2022] Open
Abstract
Lung cancer is the leading cause of cancer-related mortality, and about 85% of the cases are non-small-cell lung cancer (NSCLC). Importantly, recent advance in cancer research suggests that altering cancer cell bioenergetics can provide an effective way to target such advanced cancer cells that have acquired mutations in multiple cellular regulators. This study aims to identify bioenergetic alterations in lung cancer cells by directly measuring and comparing key metabolic activities in a pair of cell lines representing normal and NSCLC cells developed from the same patient. We found that the rates of oxygen consumption and heme biosynthesis were intensified in NSCLC cells. Additionally, the NSCLC cells exhibited substantially increased levels in an array of proteins promoting heme synthesis, uptake and function. These proteins include the rate-limiting heme biosynthetic enzyme ALAS, transporter proteins HRG1 and HCP1 that are involved in heme uptake, and various types of oxygen-utilizing hemoproteins such as cytoglobin and cytochromes. Several types of human tumor xenografts also displayed increased levels of such proteins. Furthermore, we found that lowering heme biosynthesis and uptake, like lowering mitochondrial respiration, effectively reduced oxygen consumption, cancer cell proliferation, migration and colony formation. In contrast, lowering heme degradation does not have an effect on lung cancer cells. These results show that increased heme flux and function are a key feature of NSCLC cells. Further, increased generation and supply of heme and oxygen-utilizing hemoproteins in cancer cells will lead to intensified oxygen consumption and cellular energy production by mitochondrial respiration, which would fuel cancer cell proliferation and progression. The results show that inhibiting heme and respiratory function can effectively arrest the progression of lung cancer cells. Hence, understanding heme function can positively impact on research in lung cancer biology and therapeutics.
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Affiliation(s)
- Jagmohan Hooda
- Department of Molecular and Cell Biology, Center for Systems Biology, University of Texas at Dallas, Richardson, Texas, United States of America
| | - Daniela Cadinu
- Department of Molecular and Cell Biology, Center for Systems Biology, University of Texas at Dallas, Richardson, Texas, United States of America
| | - Md Maksudul Alam
- Department of Molecular and Cell Biology, Center for Systems Biology, University of Texas at Dallas, Richardson, Texas, United States of America
| | - Ajit Shah
- Department of Molecular and Cell Biology, Center for Systems Biology, University of Texas at Dallas, Richardson, Texas, United States of America
| | - Thai M. Cao
- Department of Molecular and Cell Biology, Center for Systems Biology, University of Texas at Dallas, Richardson, Texas, United States of America
| | - Laura A. Sullivan
- Division of Surgical Oncology, Department of Surgery, The Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Rolf Brekken
- Division of Surgical Oncology, Department of Surgery, The Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Li Zhang
- Department of Molecular and Cell Biology, Center for Systems Biology, University of Texas at Dallas, Richardson, Texas, United States of America
- * E-mail:
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Hiyama K, Matsui H, Tamura M, Shimokawa O, Hiyama M, Kaneko T, Nagano Y, Hyodo I, Tanaka J, Miwa Y, Ogawa T, Nakanishi T, Tamai I. Cancer cells uptake porphyrinsviaheme carrier protein 1. J PORPHYR PHTHALOCYA 2013. [DOI: 10.1142/s1088424612501192] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Although exogenous porphyrin accumulation in cancer cells is important for the success of photodynamic therapies, the mechanism is not clear. We hypothesized that a newly reported transporter, heme carrier protein 1 (HCP1), is highly expressed in cancer cells, and transports porphyrins into the cells. We investigated the following three unknowns: whether cancer cells take up hematoporphyrin derivative via HCP1, whether HCP1 is involved in photodynamic therapies, and whether cancer cells highly express HCP1. First, when HCP1-overexpressed cells were treated with hematoporphyrin derivative and then exposed to an eximer laser beam, they emitted a significantly higher intensity of hematoporphyrin derivative fluorescence and became more susceptible to the laser beam than control. Second, when three other types of cancer cells with silenced HCP1 were treated with hematoporphyrin derivative and then exposed to the laser beam, they emitted a significantly lower intensity of hematoporphyrin derivative fluorescence. Third, non-cancer cells slightly expressed HCP1; on the other hand, the three other types of cancer cells clearly expressed HCP1. These results indicated that cancer cells uptake hematoporphyrin derivative via HCP1 and over-expression of HCP1 increases the efficacy of photodynamic therapies by increasing porphyrin accumulation in the cells. This is the first report about a transporter of porphyrin in cancer cells.
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Affiliation(s)
- Kazuhiro Hiyama
- Division of Gastroenterology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8575, Japan
| | - Hirofumi Matsui
- Division of Gastroenterology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8575, Japan
| | - Masato Tamura
- Division of Gastroenterology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8575, Japan
| | - Osamu Shimokawa
- Division of Gastroenterology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8575, Japan
| | - Mariko Hiyama
- Division of Gastroenterology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8575, Japan
| | - Tsuyoshi Kaneko
- Division of Gastroenterology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8575, Japan
| | - Yumiko Nagano
- Division of Gastroenterology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8575, Japan
| | - Ichinosuke Hyodo
- Division of Gastroenterology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8575, Japan
| | - Junko Tanaka
- Department of Molecular Pharmacology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8575, Japan
| | - Yoshihiro Miwa
- Department of Molecular Pharmacology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8575, Japan
| | - Tetsuo Ogawa
- Department of Membrane Transport and Biopharmaceutics, School of Pharmaceutical Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
| | - Takeo Nakanishi
- Department of Membrane Transport and Biopharmaceutics, School of Pharmaceutical Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
| | - Ikumi Tamai
- Department of Membrane Transport and Biopharmaceutics, School of Pharmaceutical Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
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Abstract
Iron metabolism has been intensively examined over the last decade and there are many new players in this field which are worth to be introduced. Since its discovery many studies confirmed role of liver hormone hepcidin as key regulator of iron metabolism and pointed out liver as the central organ of system iron homeostasis. Liver cells receive multiple signals related to iron balance and respond by transcriptional regulation of hepcidin expression. This liver hormone is negative regulator of iron metabolism that represses iron efflux from macrophages, hepatocytes and enterocytes by its binding to iron export protein ferroportin. Ferroportin degradation leads to cellular iron retention and decreased iron availability. At level of a cell IRE/IRP (iron responsive elements/iron responsive proteins) system allows tight regulation of iron assimilation that prevents an excess of free intracellular iron which could lead to oxidative stress and damage of DNA, proteins and lipid membranes by ROS (reactive oxygen species). At the same time IRE/IRP system provides sufficient iron in order to meet the metabolic needs. Recently a significant progress in understanding of iron metabolism has been made and new molecular participants have been characterized. Article gives an overview of the current understanding of iron metabolism: absorption, distribution, cellular uptake, release, and storage. We also discuss mechanisms underlying systemic and cellular iron regulation with emphasis on central regulatory hormone hepcidin.
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Affiliation(s)
- Leida Tandara
- Department of Medical Laboratory Diagnosis, University Hospital Center Split, Split, Croatia.
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31
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Skjørringe T, Møller LB, Moos T. Impairment of interrelated iron- and copper homeostatic mechanisms in brain contributes to the pathogenesis of neurodegenerative disorders. Front Pharmacol 2012; 3:169. [PMID: 23055972 PMCID: PMC3456798 DOI: 10.3389/fphar.2012.00169] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 08/29/2012] [Indexed: 01/01/2023] Open
Abstract
Iron and copper are important co-factors for a number of enzymes in the brain, including enzymes involved in neurotransmitter synthesis and myelin formation. Both shortage and an excess of iron or copper will affect the brain. The transport of iron and copper into the brain from the circulation is strictly regulated, and concordantly protective barriers, i.e., the blood-brain barrier (BBB) and the blood-cerebrospinal fluid (CSF) barrier (BCB) have evolved to separate the brain environment from the circulation. The uptake mechanisms of the two metals interact. Both iron deficiency and overload lead to altered copper homeostasis in the brain. Similarly, changes in dietary copper affect the brain iron homeostasis. Moreover, the uptake routes of iron and copper overlap each other which affect the interplay between the concentrations of the two metals in the brain. The divalent metal transporter-1 (DMT1) is involved in the uptake of both iron and copper. Furthermore, copper is an essential co-factor in numerous proteins that are vital for iron homeostasis and affects the binding of iron-response proteins to iron-response elements in the mRNA of the transferrin receptor, DMT1, and ferroportin, all highly involved in iron transport. Iron and copper are mainly taken up at the BBB, but the BCB also plays a vital role in the homeostasis of the two metals, in terms of sequestering, uptake, and efflux of iron and copper from the brain. Inside the brain, iron and copper are taken up by neurons and glia cells that express various transporters.
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Affiliation(s)
- Tina Skjørringe
- Section of Neurobiology, Biomedicine Group, Institute of Medicine and Health Technology, Aalborg University Aalborg, Denmark ; Center for Applied Human Molecular Genetics, Department of Kennedy Centre, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
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Le Blanc S, Garrick MD, Arredondo M. Heme carrier protein 1 transports heme and is involved in heme-Fe metabolism. Am J Physiol Cell Physiol 2012; 302:C1780-5. [DOI: 10.1152/ajpcell.00080.2012] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Heme-Fe is an important source of dietary iron in humans; however, the mechanism for heme-Fe uptake by enterocytes is poorly understood. Heme carrier protein 1 (HCP1) was originally identified as mediating heme-Fe transport although it later emerged that it was a folate transporter. We asked what happened to heme-Fe and folate uptake and the relative abundance of hcp1 and ho1 mRNA in Caco-2 cells after knockdown by transfection with HCP1-directed short hairpin (sh)RNA. Control Caco-2 cells were cultured in bicameral chambers with 0–80 μM heme-Fe for selected times. Intracellular Fe and heme concentration increased in Caco-2 cells reflecting higher external heme-Fe concentrations. Maximum Fe, heme, and heme oxygenase 1 (HO1) expression and activity were observed between 12 and 24 h of incubation. Quantitative RT-PCR for hcp1 revealed that its mRNA decreased at 20 μM heme-Fe while ho1 mRNA and activity increased. When shRNA knocked down hcp1 mRNA, heme-55Fe uptake and [3H]folate transport mirrored the mRNA decrease, ho1 mRNA increased, and flvcr mRNA was unchanged. These data argue that HCP1 is involved in low-affinity heme-Fe uptake not just in folate transport.
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Affiliation(s)
- Solange Le Blanc
- Micronutrient Laboratory, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile; and
| | - Michael D. Garrick
- Department of Biochemistry, State University of New York, Buffalo, New York
| | - Miguel Arredondo
- Micronutrient Laboratory, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile; and
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Jahn MR, Nawroth T, Fütterer S, Wolfrum U, Kolb U, Langguth P. Iron Oxide/Hydroxide Nanoparticles with Negatively Charged Shells Show Increased Uptake in Caco-2 Cells. Mol Pharm 2012; 9:1628-37. [DOI: 10.1021/mp200628u] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Markus R. Jahn
- Department of Biopharmacy and
Pharmaceutical Technology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Mainz, Germany
| | - Thomas Nawroth
- Department of Biopharmacy and
Pharmaceutical Technology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Mainz, Germany
| | - Sören Fütterer
- Department of Biopharmacy and
Pharmaceutical Technology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Mainz, Germany
| | - Uwe Wolfrum
- Department of Cell and Matrix
Biology, Institute of Zoology, Johannes Gutenberg University, Mainz, Germany
| | - Ute Kolb
- Institute
of Physical Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Peter Langguth
- Department of Biopharmacy and
Pharmaceutical Technology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Mainz, Germany
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34
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Larsen R, Gouveia Z, Soares MP, Gozzelino R. Heme cytotoxicity and the pathogenesis of immune-mediated inflammatory diseases. Front Pharmacol 2012; 3:77. [PMID: 22586395 PMCID: PMC3343703 DOI: 10.3389/fphar.2012.00077] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 04/11/2012] [Indexed: 01/01/2023] Open
Abstract
Heme, iron (Fe) protoporphyrin IX, functions as a prosthetic group in a range of hemoproteins essential to support life under aerobic conditions. The Fe contained within the prosthetic heme groups of these hemoproteins can catalyze the production of reactive oxygen species. Presumably for this reason, heme must be sequestered within those hemoproteins, thereby shielding the reactivity of its Fe-heme. However, under pathologic conditions associated with oxidative stress, some hemoproteins can release their prosthetic heme groups. While this heme is not necessarily damaging per se, it becomes highly cytotoxic in the presence of a range of inflammatory mediators such as tumor necrosis factor. This can lead to tissue damage and, as such, exacerbate the pathologic outcome of several immune-mediated inflammatory conditions. Presumably, targeting “free heme” may be used as a therapeutic intervention against these diseases.
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35
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Zhao R, Diop-Bove N, Visentin M, Goldman ID. Mechanisms of membrane transport of folates into cells and across epithelia. Annu Rev Nutr 2011; 31:177-201. [PMID: 21568705 DOI: 10.1146/annurev-nutr-072610-145133] [Citation(s) in RCA: 241] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Until recently, the transport of folates into cells and across epithelia has been interpreted primarily within the context of two transporters with high affinity and specificity for folates, the reduced folate carrier and the folate receptors. However, there were discrepancies between the properties of these transporters and characteristics of folate transport in many tissues, most notably the intestinal absorption of folates, in terms of pH dependency and substrate specificity. With the recent cloning of the proton-coupled folate transporter (PCFT) and the demonstration that this transporter is mutated in hereditary folate malabsorption, an autosomal recessive disorder, the molecular basis for this low-pH transport activity is now understood. This review focuses on the properties of PCFT and briefly addresses the two other folate-specific transporters along with other facilitative and ATP-binding cassette (ABC) transporters with folate transport activities. The role of these transporters in the vectorial transport of folates across epithelia is considered.
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Affiliation(s)
- Rongbao Zhao
- Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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36
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Jahn MR, Shukoor I, Tremel W, Wolfrum U, Kolb U, Nawroth T, Langguth P. Hemin-coupled iron(III)-hydroxide nanoparticles show increased uptake in Caco-2 cells. J Pharm Pharmacol 2011; 63:1522-30. [DOI: 10.1111/j.2042-7158.2011.01356.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Abstract
Objectives
The absorption of commonly used ferrous iron salts from intestinal segments at neutral to slightly alkaline pH is low, mainly because soluble ferrous iron is easily oxidized to poorly soluble ferric iron and ferrous iron but not ferric iron is carried by the divalent metal transporter DMT-1. Moreover, ferrous iron frequently causes gastrointestinal side effects. In iron(III)-hydroxide nanoparticles hundreds of ferric iron atoms are safely packed in nanoscaled cores surrounded by a solubilising carbohydrate shell, yet bioavailability from such particles is insufficient when compared with ferrous salts. To increase their intestinal uptake iron(III)-hydroxide nanoparticles were coupled in this study with the protoporphyrin hemin, which undergoes carrier-mediated uptake in the intestine.
Methods
Uptake of iron(III)-hydroxide nanoparticles with hemin covalently coupled by DCC reaction was measured in Caco-2 cells with a colorimetric assay and visualized by transmission electron microscopy.
Key findings
Nanoparticles were taken up by carrier-mediated transport, since uptake was temperature-dependent and increased with an increasing hemin substitution grade. Furthermore, uptake decreased with an increasing concentration of free hemin, due to competition for carrier-mediated uptake.
Conclusions
Hemin-coupled iron(III)-hydroxide nanoparticles were carried by a heme specific transport system, probably via receptor mediated endocytosis. It can be expected that this system shows improved absorption of iron compared with uncoupled iron(III)-hydroxide nanoparticles, which exist on the market today.
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Affiliation(s)
- Markus Richard Jahn
- Biopharmacy and Pharmaceutical Technology, Institute of Pharmacy and Biochemistry, Mainz, Germany
| | - Ibrahim Shukoor
- Institute of Inorganic and Analytical Chemistry, Mainz, Germany
| | - Wolfgang Tremel
- Institute of Inorganic and Analytical Chemistry, Mainz, Germany
| | - Uwe Wolfrum
- Cell and Matrix Biology, Institute of Zoology, Mainz, Germany
| | - Ute Kolb
- Institute of Physical Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Thomas Nawroth
- Biopharmacy and Pharmaceutical Technology, Institute of Pharmacy and Biochemistry, Mainz, Germany
| | - Peter Langguth
- Biopharmacy and Pharmaceutical Technology, Institute of Pharmacy and Biochemistry, Mainz, Germany
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37
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Chepelev NL, Willmore WG. Regulation of iron pathways in response to hypoxia. Free Radic Biol Med 2011; 50:645-66. [PMID: 21185934 DOI: 10.1016/j.freeradbiomed.2010.12.023] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Revised: 12/13/2010] [Accepted: 12/15/2010] [Indexed: 10/24/2022]
Abstract
Constituting an integral part of a heme's porphyrin ring, iron is essential for supplying cells and tissues with oxygen. Given tight links between oxygen delivery and iron availability, it is not surprising that iron deprivation and oxygen deprivation (hypoxia) have very similar consequences at the molecular level. Under hypoxia, the expression of major iron homeostasis genes including transferrin, transferrin receptor, ceruloplasmin, and heme oxygenase-1 is activated by hypoxia-inducible factors to provide increased iron availability for erythropoiesis in an attempt to enhance oxygen uptake and delivery to hypoxic cells. Iron-response proteins (IRP1 and IRP2) and "cap-n-collar" bZIP transcriptional factors (NE-F2 p45; Nrf1, 2, and 3; Bach1 and 2) also control gene and protein expression of the key iron homeostasis proteins. In this article, we give an overview of the mechanisms by which iron pathways are regulated by hypoxia at multiple levels. In addition, potential clinical benefits of manipulating iron pathways in the hypoxia-related conditions anemia and ischemia are discussed.
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38
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Geisser P, Burckhardt S. The pharmacokinetics and pharmacodynamics of iron preparations. Pharmaceutics 2011; 3:12-33. [PMID: 24310424 PMCID: PMC3857035 DOI: 10.3390/pharmaceutics3010012] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 12/27/2010] [Indexed: 12/13/2022] Open
Abstract
Standard approaches are not appropriate when assessing pharmacokinetics of iron supplements due to the ubiquity of endogenous iron, its compartmentalized sites of action, and the complexity of the iron metabolism. The primary site of action of iron is the erythrocyte, and, in contrast to conventional drugs, no drug-receptor interaction takes place. Notably, the process of erythropoiesis, i.e., formation of new erythrocytes, takes 3–4 weeks. Accordingly, serum iron concentration and area under the curve (AUC) are clinically irrelevant for assessing iron utilization. Iron can be administered intravenously in the form of polynuclear iron(III)-hydroxide complexes with carbohydrate ligands or orally as iron(II) (ferrous) salts or iron(III) (ferric) complexes. Several approaches have been employed to study the pharmacodynamics of iron after oral administration. Quantification of iron uptake from radiolabeled preparations by the whole body or the erythrocytes is optimal, but alternatively total iron transfer can be calculated based on known elimination rates and the intrinsic reactivity of individual preparations. Degradation kinetics, and thus the safety, of parenteral iron preparations are directly related to the molecular weight and the stability of the complex. High oral iron doses or rapid release of iron from intravenous iron preparations can saturate the iron transport system, resulting in oxidative stress with adverse clinical and subclinical consequences. Appropriate pharmacokinetics and pharmacodynamics analyses will greatly assist our understanding of the likely contribution of novel preparations to the management of anemia.
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Affiliation(s)
- Peter Geisser
- Research & Development Department, Vifor Pharma - Vifor International Inc, Rechenstrasse 37, St Gallen, CH-9001, Switzerland.
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39
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Recalcati S, Minotti G, Cairo G. Iron regulatory proteins: from molecular mechanisms to drug development. Antioxid Redox Signal 2010; 13:1593-616. [PMID: 20214491 DOI: 10.1089/ars.2009.2983] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Eukaryotic cells require iron for survival but, as an excess of poorly liganded iron can lead to the catalytic production of toxic radicals that can damage cell structures, regulatory mechanisms have been developed to maintain appropriate cell and body iron levels. The interactions of iron responsive elements (IREs) with iron regulatory proteins (IRPs) coordinately regulate the expression of the genes involved in iron uptake, use, storage, and export at the post-transcriptional level, and represent the main regulatory network controlling cell iron homeostasis. IRP1 and IRP2 are similar (but not identical) proteins with partially overlapping and complementary functions, and control cell iron metabolism by binding to IREs (i.e., conserved RNA stem-loops located in the untranslated regions of a dozen mRNAs directly or indirectly related to iron metabolism). The discovery of the presence of IREs in a number of other mRNAs has extended our knowledge of the influence of the IRE/IRP regulatory network to new metabolic pathways, and it has been recently learned that an increasing number of agents and physiopathological conditions impinge on the IRE/IRP system. This review focuses on recent findings concerning the IRP-mediated regulation of iron homeostasis, its alterations in disease, and new research directions to be explored in the near future.
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Affiliation(s)
- Stefania Recalcati
- Department of Human Morphology and Biomedical Sciences Città Studi, University of Milan, Milano, Italy
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40
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Chen H, Attieh ZK, Dang T, Huang G, van der Hee RM, Vulpe C. Decreased hephaestin expression and activity leads to decreased iron efflux from differentiated Caco2 cells. J Cell Biochem 2009; 107:803-8. [PMID: 19452451 DOI: 10.1002/jcb.22178] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Iron is transported across intestinal brush border cells into the circulation in at least two distinct steps. Iron can enter the enterocyte via the apical surface through several paths. However, iron egress from the basolateral side of enterocytes converges on a single export pathway requiring the iron transporter, ferroportin1, and hephaestin, a ferroxidase. Copper deficiency leads to reduced hephaestin protein expression and activity in mouse enterocytes and intestinal cell lines. We tested the effect of copper deficiency on differentiated Caco2 cells grown in transwells and found decreased hephaestin protein expression and activity as well as reduced ferroportin1 protein levels. Furthermore, the decrease in hephaestin levels correlates with a decrease of (55)Fe release from the basolateral side of Caco2 cells. Presence of ceruloplasmin, apo-transferrin or holo-transferrin did not significantly alter the results observed. Repletion of copper in Caco2 cells leads to reconstitution of hephaestin protein expression, activity, and transepithelial iron transport.
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Affiliation(s)
- Huijun Chen
- Department of Nutritional Science and Toxicology, University of California, Berkeley, 94720-3104, USA.
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41
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Hower V, Mendes P, Torti FM, Laubenbacher R, Akman S, Shulaev V, Torti SV. A general map of iron metabolism and tissue-specific subnetworks. MOLECULAR BIOSYSTEMS 2009; 5:422-43. [PMID: 19381358 PMCID: PMC2680238 DOI: 10.1039/b816714c] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Iron is required for survival of mammalian cells. Recently, understanding of iron metabolism and trafficking has increased dramatically, revealing a complex, interacting network largely unknown just a few years ago. This provides an excellent model for systems biology development and analysis. The first step in such an analysis is the construction of a structural network of iron metabolism, which we present here. This network was created using CellDesigner version 3.5.2 and includes reactions occurring in mammalian cells of numerous tissue types. The iron metabolic network contains 151 chemical species and 107 reactions and transport steps. Starting from this general model, we construct iron networks for specific tissues and cells that are fundamental to maintaining body iron homeostasis. We include subnetworks for cells of the intestine and liver, tissues important in iron uptake and storage, respectively, as well as the reticulocyte and macrophage, key cells in iron utilization and recycling. The addition of kinetic information to our structural network will permit the simulation of iron metabolism in different tissues as well as in health and disease.
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Affiliation(s)
- Valerie Hower
- Department of Cancer Biology, Wake Forest University School of Medicine, Medical Center Blvd, Winston Salem, NC 27157, USA
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42
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Bleackley MR, Wong AY, Hudson DM, Wu CHY, MacGillivray RT. Blood Iron Homeostasis: Newly Discovered Proteins and Iron Imbalance. Transfus Med Rev 2009; 23:103-23. [DOI: 10.1016/j.tmrv.2008.12.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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43
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Gaur M, Puri N, Manoharlal R, Rai V, Mukhopadhayay G, Choudhury D, Prasad R. MFS transportome of the human pathogenic yeast Candida albicans. BMC Genomics 2008; 9:579. [PMID: 19055746 PMCID: PMC2636803 DOI: 10.1186/1471-2164-9-579] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Accepted: 12/03/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The major facilitator superfamily (MFS) is one of the two largest superfamilies of membrane transporters present ubiquitously in bacteria, archaea, and eukarya and includes members that function as uniporters, symporters or antiporters. We report here the complete transportome of MFS proteins of a human pathogenic yeast Candida albicans. RESULTS Computational analysis of C. albicans genome enabled us to identify 95 potential MFS proteins which clustered into 17 families using Saier's Transport Commission (TC) system. Among these SP, DHA1, DHA2 and ACS represented major families consisting of 22, 22, 9 and 16 members, respectively. Family designations in C. albicans were validated by subjecting Saccharomyces cerevisiae genome to TC system. Based on the published available genomics/proteomics data, 87 of the putative MFS genes of C. albicans were found to express either at mRNA or protein levels. We checked the expression of the remaining 8 genes by using RT-PCR and observed that they are not expressed under basal growth conditions implying that either these 8 genes are expressed under specific growth conditions or they may be candidates for pseudogenes. CONCLUSION The in silico characterisation of MFS transporters in Candida albicans genome revealed a large complement of MFS transporters with most of them showing expression. Considering the clinical relevance of C. albicans and role of MFS members in antifungal resistance and nutrient transport, this analysis would pave way for identifying their physiological relevance.
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Affiliation(s)
- Manisha Gaur
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India.
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44
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Zhang AS, Enns CA. Iron homeostasis: recently identified proteins provide insight into novel control mechanisms. J Biol Chem 2008; 284:711-5. [PMID: 18757363 DOI: 10.1074/jbc.r800017200] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Iron is an essential nutrient required for a variety of biochemical processes. It is a vital component of the heme in hemoglobin, myoglobin, and cytochromes and is also an essential cofactor for non-heme enzymes such as ribonucleotide reductase, the limiting enzyme for DNA synthesis. When in excess, iron is toxic because it generates superoxide anions and hydroxyl radicals that react readily with biological molecules, including proteins, lipids, and DNA. As a result, humans possess elegant control mechanisms to maintain iron homeostasis by coordinately regulating iron absorption, iron recycling, and mobilization of stored iron. Disruption of these processes causes either iron-deficient anemia or iron overload disorders. In this minireview, we focus on the roles of recently identified proteins in the regulation of iron homeostasis.
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Affiliation(s)
- An-Sheng Zhang
- Department of Cell and Developmental Biology, Oregon Health & Science University, Portland, Oregon 97239, USA
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Subramanian VS, Reidling JC, Said HM. Differentiation-dependent regulation of the intestinal folate uptake process: studies with Caco-2 cells and native mouse intestine. Am J Physiol Cell Physiol 2008; 295:C828-35. [PMID: 18650265 DOI: 10.1152/ajpcell.00249.2008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Differentiation of intestinal epithelial cells is accompanied by alterations in levels of expression of many genes, including those involved in nutrient uptake. Effects of differentiation of intestinal epithelial cells on the physiological and molecular parameters of the intestinal folate uptake process are not well characterized. To address this issue, we used two models, Caco-2 cells and native mouse intestine. Studies with Caco-2 cells showed a significant increase in the initial rate of carrier-mediated folic acid uptake during differentiation (i.e., as the cells transitioned from preconfluent to confluent and then to postconfluent stages). This increase was associated with an increase in the level of expression of the human reduced folate carrier (hRFC) and the human proton-coupled folate transporter (hPCFT) both at the protein and mRNA levels with differentiation; it was also associated with a significant increase in activity of the hRFC and hPCFT promoters. Studies with native mouse intestine showed a significantly higher folate uptake in villus compared with crypt cells, which was again associated with a significantly higher level of expression of the mouse RFC and PCFT at the protein and mRNA levels. Together, these studies demonstrate that the intestinal folate uptake process undergoes differentiation-dependent regulation and that this regulation is mediated via changes in the level of expression of both the RFC and PCFT. In addition, the studies suggest the possible involvement (at least in part) of a transcriptional mechanism(s) in this type of regulation of the intestinal folate uptake process.
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46
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Richardson DR, Kalinowski DS, Lau S, Jansson PJ, Lovejoy DB. Cancer cell iron metabolism and the development of potent iron chelators as anti-tumour agents. Biochim Biophys Acta Gen Subj 2008; 1790:702-17. [PMID: 18485918 DOI: 10.1016/j.bbagen.2008.04.003] [Citation(s) in RCA: 175] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Accepted: 04/21/2008] [Indexed: 02/08/2023]
Abstract
Cancer contributes to 50% of deaths worldwide and new anti-tumour therapeutics with novel mechanisms of actions are essential to develop. Metabolic inhibitors represent an important class of anti-tumour agents and for many years, agents targeting the nutrient folate were developed for the treatment of cancer. This is because of the critical need of this factor for DNA synthesis. Similarly to folate, Fe is an essential cellular nutrient that is critical for DNA synthesis. However, in contrast to folate, there has been limited effort applied to specifically design and develop Fe chelators for the treatment of cancer. Recently, investigations have led to the generation of novel di-2-pyridylketone thiosemicarbazone (DpT) and 2-benzoylpyridine thiosemicarbazone (BpT) group of ligands that demonstrate marked and selective anti-tumour activity in vitro and also in vivo against a wide spectrum of tumours. Indeed, administration of these compounds to mice did not induce whole body Fe-depletion or disturbances in haematological or biochemical indices due to the very low doses required. The mechanism of action of these ligands includes alterations in expression of molecules involved in cell cycle control and metastasis suppression, as well as the generation of redox-active Fe complexes. This review examines the alterations in Fe metabolism in tumour cells and the systematic development of novel aroylhydrazone and thiosemicarbazone Fe chelators for cancer treatment.
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Affiliation(s)
- D R Richardson
- Department of Pathology and Bosch Institute, Iron Metabolism and Chelation Program, Blackburn Building, University of Sydney, Sydney, New South Wales, 2006, Australia.
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Umapathy NS, Gnana-Prakasam JP, Martin PM, Mysona B, Dun Y, Smith SB, Ganapathy V, Prasad PD. Cloning and functional characterization of the proton-coupled electrogenic folate transporter and analysis of its expression in retinal cell types. Invest Ophthalmol Vis Sci 2007; 48:5299-305. [PMID: 17962486 DOI: 10.1167/iovs.07-0288] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
PURPOSE In a prior study the cellular uptake of folate was investigated in the retina. Recently, a new proton-coupled folate transporter (PCFT) in human intestine was reported. In the present study, the expression of this novel transporter in the retina was determined, the mouse orthologue was cloned from retinal tissue, and its transport function was characterized. METHODS RT-PCR and folate uptake measurements were used to detect the expression of PCFT in mouse retina and in retinal cell types. The expression of PCFT mRNA in intact retina was investigated by in situ hybridization. Mouse PCFT cDNA was cloned, and its transport characteristics were analyzed by electrophysiological methods after expression of the cloned transporter in Xenopus laevis oocytes. RESULTS RT-PCR showed expression of PCFT mRNA in both neural retina and RPE eye cup. In situ hybridization detected PCFT mRNA in all retinal cell layers. Proton-coupled folate uptake was detectable in primary cultures of ganglion, Müller, and RPE cells of mouse retina and in RPE, ganglion, and Müller cells of human or rat origin. In X. laevis oocytes expressing the cloned mouse PCFT, folate and its derivatives methotrexate and 5-methyltetrahydrofolate induced H(+)-coupled inward currents with K(t) values of 1.2 +/- 0.1, 4.6 +/- 0.5, and 3.5 +/- 0.8 microM, respectively. The transport process showed an H(+)-folate stoichiometry of 1:1, suggesting that PCFT transports the zwitterionic form of folate. CONCLUSIONS This is the first report on the expression of PCFT in the retina. All cell layers of the retina express this transporter. Mouse PCFT, cloned from retina, mediates H(+)-coupled electrogenic transport of folate and its derivatives.
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Affiliation(s)
- Nagavedi S Umapathy
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, GA 30912, USA
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Subramanian VS, Marchant JS, Said HM. Apical membrane targeting and trafficking of the human proton-coupled transporter in polarized epithelia. Am J Physiol Cell Physiol 2007; 294:C233-40. [PMID: 18003745 DOI: 10.1152/ajpcell.00468.2007] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The human proton-coupled folate transporter (hPCFT) is a recently discovered intestinal transporter involved in folate uptake in epithelia (and possibly other cells). Little is currently known about the structure-function relationship of the different domains of this transporter, particularly which regions are important for substrate transport as well as targeting of the transporter to the apical cell surface of polarized cells. Here we have investigated the role of the COOH-terminal domain and a well-conserved sequence separating transmembrane (TM) domains TM2 and TM3 (DXXGRR; amino acids 109-114) speculated by others to be important for transport function. Using live cell imaging approaches, we show that 1) an hPCFT-yellow fluorescent protein construct is functionally expressed at the apical membrane domain and is localized differentially to the human reduced folate carrier; 2) the predicted cytoplasmic COOH-terminal region of hPCFT is not essential for apical targeting or transporter functionality; 3) mutations that ablate a consensus beta-turn sequence separating predicted TM2 and TM3 abolished apical [(3)H]folic acid uptake as a consequence of endoplasmic reticulum retention of mutant, likely misfolded, transporters; and 4) cell surface delivery of hPCFT is disrupted by microtubule depolymerization or by overexpression of the dynactin complex dynamitin (p50). For the first time, our data present information regarding structure-function and membrane targeting of the hPCFT polypeptide, as well as the mechanisms that control its steady-state expression in polarized cells.
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Chung B, Matak P, McKie AT, Sharp P. Leptin increases the expression of the iron regulatory hormone hepcidin in HuH7 human hepatoma cells. J Nutr 2007; 137:2366-70. [PMID: 17951471 DOI: 10.1093/jn/137.11.2366] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Obesity is a major global health problem and is associated with low-grade inflammation and, in a number of cases, poor iron status. We speculated that the adipokine leptin might play a role in regulating iron metabolism in the overweight population because it shares a number of common biological features with IL-6, a major factor in the development of the anemia of chronic disease via its stimulatory actions on the production and release of the iron regulatory hormone hepcidin. To test this hypothesis, we exposed HuH7 human hepatoma cells to leptin and measured hepcidin mRNA expression by quantitative PCR. HuH7 cells were also transfected with a hepcidin promoter-luciferase reporter gene construct to investigate transcriptional regulation of hepcidin. In leptin-treated cells, hepcidin mRNA expression was enhanced significantly. Preincubation with a Janus kinase (JAK) 2 inhibitor significantly diminished this response. Hepcidin promoter activity was also increased in the presence of leptin. This effect was decreased either by mutation of the signal transducer and activator of transcription (STAT) 3 binding motif in the hepcidin promoter or by coexpressing a dominant-negative STAT3 mutant. These data suggest that leptin upregulates hepatic hepcidin expression through the JAK2/STAT3 signaling pathway. As a consequence, the increased production of leptin in overweight individuals might be a major contributor to the aberrant iron status observed in these population groups.
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Affiliation(s)
- Bomee Chung
- Nutritional Sciences Division, King's College London, London SE1 9NH, UK
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Qiu A, Min SH, Jansen M, Malhotra U, Tsai E, Cabelof DC, Matherly LH, Zhao R, Akabas MH, Goldman ID. Rodent intestinal folate transporters (SLC46A1): secondary structure, functional properties, and response to dietary folate restriction. Am J Physiol Cell Physiol 2007; 293:C1669-78. [PMID: 17898134 DOI: 10.1152/ajpcell.00202.2007] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This laboratory recently identified a human gene that encodes a novel folate transporter [Homo sapiens proton-coupled folate transporter (HsPCFT); SLC46A1] required for intestinal folate absorption. This study focused on mouse (Mus musculus) PCFT (MmPCFT) and rat (Rattus norvegicus) PCFT (RnPCFT) and addresses their secondary structure, specificity, tissue expression, and regulation by dietary folates. Both rodent PCFT proteins traffic to the cell membrane with the NH(2)- and COOH-termini accessible to antibodies targeted to these domains only in permeabilized HeLa cells. This, together with computer-based topological analyses, is consistent with a model in which rodent PCFT proteins likely contain 12 transmembrane domains. Transport of [(3)H]folates was optimal at pH 5.5 and decreased with increasing pH due to an increase in K(m) and a decrease in V(max). At pH 7.0, folic acid and methotrexate influx was negligible, but there was residual (6S)5-methyltetrahydrofolate transport. Uptake of folates in PCFT-injected Xenopus oocytes was electrogenic and pH dependent. Folic acid influx K(m) values of MmPCFT and RnPCFT, assessed electrophysiologically, were 0.7 and 0.3 microM at pH 5.5 and 1.1 and 0.8 microM at pH 6.5, respectively. Rodent PCFTs were highly specific for monoglutamyl but not polyglutamyl methotrexate. MmPCFT mRNA was highly expressed in the duodenum, proximal jejunum, liver, and kidney with lesser expression in the brain and other tissues. MmPCFT protein was localized to the apical brush-border membrane of the duodenum and proximal jejunum. MmPCFT mRNA levels increased approximately 13-fold in the proximal small intestine in mice fed a folate-deficient vesus folate-replete diet, consistent with the critical role that PCFT plays in intestinal folate absorption.
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Affiliation(s)
- Andong Qiu
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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