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Zhang DL, Ollivierre H, Rouault TA. Using Biotinylated Iron-Responsive Element to Analyze the Activity of Iron Regulatory Proteins. Int J Mol Sci 2024; 25:4852. [PMID: 38732071 PMCID: PMC11084215 DOI: 10.3390/ijms25094852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 04/26/2024] [Accepted: 04/27/2024] [Indexed: 05/13/2024] Open
Abstract
Iron regulatory proteins (IRP1 and IRP2) are the master regulators of mammalian iron homeostasis. They bind to the iron-responsive elements (IREs) of the transcripts of iron-related genes to regulate their expression, thereby maintaining cellular iron availability. The primary method to measure the IRE-binding activity of IRPs is the electrophoresis mobility shift assay (EMSA). This method is particularly useful for evaluating IRP1 activity, since IRP1 is a bifunctional enzyme and its protein levels remain similar during conversion between the IRE-binding protein and cytosolic aconitase forms. Here, we exploited a method of using a biotinylated-IRE probe to separate IRE-binding IRPs followed by immunoblotting to analyze the IRE-binding activity. This method allows for the successful measurement of IRP activity in cultured cells and mouse tissues under various iron conditions. By separating IRE-binding IRPs from the rest of the lysates, this method increases the specificity of IRP antibodies and verifies whether a band represents an IRP, thereby revealing some previously unrecognized information about IRPs. With this method, we showed that the S711-phosphorylated IRP1 was found only in the IRE-binding form in PMA-treated Hep3B cells. Second, we found a truncated IRE-binding IRP2 isoform that is generated by proteolytic cleavage on sites in the 73aa insert region of the IRP2 protein. Third, we found that higher levels of SDS, compared to 1-2% SDS in regular loading buffer, could dramatically increase the band intensity of IRPs in immunoblots, especially in HL-60 cells. Fourth, we found that the addition of SDS or LDS to cell lysates activated protein degradation at 37 °C or room temperature, especially in HL-60 cell lysates. As this method is more practical, sensitive, and cost-effective, we believe that its application will enhance future research on iron regulation and metabolism.
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Affiliation(s)
| | | | - Tracey A. Rouault
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA; (D.-L.Z.); (H.O.)
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2
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Wang Y, Xiao M, Cai F, Li Y, Shi T, Zhou X, Tian S, Huang D. Roxadustat ameliorates vascular calcification in CKD rats by regulating HIF-2α/HIF-1α. ENVIRONMENTAL TOXICOLOGY 2024; 39:2363-2373. [PMID: 38156404 DOI: 10.1002/tox.24116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 12/08/2023] [Accepted: 12/10/2023] [Indexed: 12/30/2023]
Abstract
Vascular calcification (VC) is a common complication of chronic kidney disease (CKD). VC is a gene-regulated process similar to osteogenic differentiation. There are still no convincing schemes to prevent and reduce the development of VC. It has been reported that hypoxia-inducing factor 1α (HIF-1α) and endothelin-1(ET-1) are related to VC. In this study, we found that the expression of ET-1 and HIF-1α was enhanced after VC, the interaction between HIF-1α and ET-1 was confirmed by CO-IP and luciferase experiments. We found that ET-1 was an upregulated differential gene of calcified vascular smooth muscle cells (VSMCs) through gene sequencing. However, hypoxia-inducing factor 2α (HIF-2α) and HIF-1α have antagonistic effects on each other. HIF-1α is a pro-inflammatory cytokine, and HIF-2α can improve inflammation and fibrosis. Roxadustat, as a selective PHD3 inhibitor, preferentially activates HIF-2α. It is still unclear whether roxadustat improves VC in CKD by regulating the expression of HIF-2α/HIF-1α. Alizarin red staining and western blot as well as immunohistochemical results showed that roxadustat could significantly reduce the degree of vascular and VSMCs calcification in CKD rats. Serum HIF-1α and ET-1 were significantly decreased after roxadustat treatment. In addition, western blot results showed that roxadustat could decrease the expression of HIF-1α and ET-1 in vascular tissues and calcified VSMC, but HIF-2α expression significantly increased. Interestingly, our study confirmed that activation of HIF-1α or inhibition of HIF-2α reversed the ameliorating effect of roxadustat on VC, proving that the effect mediated by roxadustat is HIF-2α/HIF-1α dependent. We have demonstrated for the first time that roxadustat improves VC in CKD rats by regulating HIF-2α/HIF-1α, thus providing a new idea for the application of roxadustat in VC of CKD.
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Affiliation(s)
- Yujing Wang
- Department of Hemodialysis, Haikou Affiliated Hospital of Central South University Xiangya School of Medicine, Haikou, China
| | - Min Xiao
- Department of Clinical Laboratory, Strategic Support Force Medical Center, Beijing, China
| | - Feng Cai
- Department of Scientific Research, Haikou Affiliated Hospital of Central South University Xiangya School of Medicine, Haikou, China
| | - Yang Li
- Department of Nephrology, Haikou Affiliated Hospital of Central South University Xiangya School of Medicine, Haikou, China
| | - Tianli Shi
- Department of Nephrology, Haikou Affiliated Hospital of Central South University Xiangya School of Medicine, Haikou, China
| | - Xiaoyan Zhou
- Department of Hemodialysis, Haikou Affiliated Hospital of Central South University Xiangya School of Medicine, Haikou, China
| | - Shuhong Tian
- Research Center for Drug Safety Evaluation of Hainan Province, Hainan Medical University, Haikou, China
| | - Denggao Huang
- Department of Central Laboratory, Haikou Affiliated Hospital of Central South University Xiangya School of Medicine, Haikou, China
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Lakhal-Littleton S, Cleland JGF. Iron deficiency and supplementation in heart failure. Nat Rev Cardiol 2024:10.1038/s41569-024-00988-1. [PMID: 38326440 DOI: 10.1038/s41569-024-00988-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/08/2024] [Indexed: 02/09/2024]
Abstract
Non-anaemic iron deficiency (NAID) is a strategic target in cardiovascular medicine because of its association with a range of adverse effects in various conditions. Endeavours to tackle NAID in heart failure have yielded mixed results, exposing knowledge gaps in how best to define 'iron deficiency' and the handling of iron therapies by the body. To address these gaps, we harness the latest understanding of the mechanisms of iron homeostasis outside the erythron and integrate clinical and preclinical lines of evidence. The emerging picture is that current definitions of iron deficiency do not assimilate the multiple influences at play in patients with heart failure and, consequently, fail to identify those with a truly unmet need for iron. Additionally, current iron supplementation therapies benefit only certain patients with heart failure, reflecting differences in the nature of the unmet need for iron and the modifying effects of anaemia and inflammation on the handling of iron therapies by the body. Building on these insights, we identify untapped opportunities in the management of NAID, including the refinement of current approaches and the development of novel strategies. Lessons learned from NAID in cardiovascular disease could ultimately translate into benefits for patients with other chronic conditions such as chronic kidney disease, chronic obstructive pulmonary disease and cancer.
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Affiliation(s)
| | - John G F Cleland
- British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
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4
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Ghatpande N, Harrer A, Azoulay-Botzer B, Guttmann-Raviv N, Bhushan S, Meinhardt A, Meyron-Holtz EG. Iron regulatory proteins 1 and 2 have opposing roles in regulating inflammation in bacterial orchitis. JCI Insight 2024; 9:e175845. [PMID: 38301068 PMCID: PMC11143929 DOI: 10.1172/jci.insight.175845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 01/30/2024] [Indexed: 02/03/2024] Open
Abstract
Acute bacterial orchitis (AO) is a prevalent cause of intrascrotal inflammation, often resulting in sub- or infertility. A frequent cause eliciting AO is uropathogenic Escherichia coli (UPEC), a gram negative pathovar, characterized by the expression of various iron acquisition systems to survive in a low-iron environment. On the host side, iron is tightly regulated by iron regulatory proteins 1 and 2 (IRP1 and -2) and these factors are reported to play a role in testicular and immune cell function; however, their precise role remains unclear. Here, we showed in a mouse model of UPEC-induced orchitis that the absence of IRP1 results in less testicular damage and a reduced immune response. Compared with infected wild-type (WT) mice, testes of UPEC-infected Irp1-/- mice showed impaired ERK signaling. Conversely, IRP2 deletion led to a stronger inflammatory response. Notably, differences in immune cell infiltrations were observed among the different genotypes. In contrast with WT and Irp2-/- mice, no increase in monocytes and neutrophils was detected in testes of Irp1-/- mice upon UPEC infection. Interestingly, in Irp1-/- UPEC-infected testes, we observed an increase in a subpopulation of macrophages (F4/80+CD206+) associated with antiinflammatory and wound-healing activities compared with WT. These findings suggest that IRP1 deletion may protect against UPEC-induced inflammation by modulating ERK signaling and dampening the immune response.
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Affiliation(s)
- Niraj Ghatpande
- Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Technion City, Haifa, Israel
| | - Aileen Harrer
- Institute of Anatomy and Cell Biology, Unit of Reproductive Biology, Justus-Liebig-University of Giessen, Giessen, Germany
| | - Bar Azoulay-Botzer
- Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Technion City, Haifa, Israel
| | - Noga Guttmann-Raviv
- Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Technion City, Haifa, Israel
| | - Sudhanshu Bhushan
- Institute of Anatomy and Cell Biology, Unit of Reproductive Biology, Justus-Liebig-University of Giessen, Giessen, Germany
| | - Andreas Meinhardt
- Institute of Anatomy and Cell Biology, Unit of Reproductive Biology, Justus-Liebig-University of Giessen, Giessen, Germany
| | - Esther G. Meyron-Holtz
- Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Technion City, Haifa, Israel
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Xu L, Peng M, Gao T, Wang D, Lian X, Sun H, Shi J, Wang Y, Wang P. Nanoenabled Intracellular Metal Ion Homeostasis Regulation for Tumor Therapy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2306203. [PMID: 38063781 PMCID: PMC10870045 DOI: 10.1002/advs.202306203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/27/2023] [Indexed: 02/17/2024]
Abstract
Endogenous essential metal ions play an important role in many life processes, especially in tumor development and immune response. The approval of various metallodrugs for tumor therapy brings more attention to the antitumor effect of metal ions. With the deepening understanding of the regulation mechanisms of metal ion homeostasis in vivo, breaking intracellular metal ion homeostasis becomes a new means to inhibit the proliferation of tumor cells and activate antitumor immune response. Diverse nanomedicines with the loading of small molecular ion regulators or metal ions have been developed to disrupt metal ion homeostasis in tumor cells, with higher safety and efficiency than free small molecular ion regulators or metal compounds. This comprehensive review focuses on the latest progress of various intracellular metal ion homeostasis regulation-based nanomedicines in tumor therapy including calcium ion (Ca2+ ), ferrous ion (Fe2+ ), cuprous ion (Cu+ ), managanese ion (Mn2+ ), and zinc ion (Zn2+ ). The physiological functions and homeostasis regulation processes of ions are summarized to guide the design of metal ion regulation-based nanomedicines. Then the antitumor mechanisms of various ions-based nanomedicines and some efficient synergistic therapies are highlighted. Finally, the challenges and future developments of ion regulation-based antitumor therapy are also discussed, hoping to provide a reference for finding more effective metal ions and synergistic therapies.
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Affiliation(s)
- Lihua Xu
- Sino‐British Research Centre for Molecular OncologyNational Centre for International Research in Cell and Gene TherapyState Key Laboratory of Esophageal Cancer Prevention & TreatmentSchool of Basic Medical SciencesAcademy of Medical SciencesZhengzhou UniversityZhengzhou450052China
| | - Mingzheng Peng
- Sino‐British Research Centre for Molecular OncologyNational Centre for International Research in Cell and Gene TherapyState Key Laboratory of Esophageal Cancer Prevention & TreatmentSchool of Basic Medical SciencesAcademy of Medical SciencesZhengzhou UniversityZhengzhou450052China
| | - Tingting Gao
- School of Pharmaceutical SciencesZhengzhou UniversityZhengzhou450001China
| | - Dandan Wang
- Sino‐British Research Centre for Molecular OncologyNational Centre for International Research in Cell and Gene TherapyState Key Laboratory of Esophageal Cancer Prevention & TreatmentSchool of Basic Medical SciencesAcademy of Medical SciencesZhengzhou UniversityZhengzhou450052China
| | - Xiaowu Lian
- Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhou450052China
| | - Huihui Sun
- Sino‐British Research Centre for Molecular OncologyNational Centre for International Research in Cell and Gene TherapyState Key Laboratory of Esophageal Cancer Prevention & TreatmentSchool of Basic Medical SciencesAcademy of Medical SciencesZhengzhou UniversityZhengzhou450052China
| | - Jinjin Shi
- School of Pharmaceutical SciencesZhengzhou UniversityZhengzhou450001China
| | - Yafeng Wang
- School of Pharmaceutical SciencesZhengzhou UniversityZhengzhou450001China
| | - Pengju Wang
- Sino‐British Research Centre for Molecular OncologyNational Centre for International Research in Cell and Gene TherapyState Key Laboratory of Esophageal Cancer Prevention & TreatmentSchool of Basic Medical SciencesAcademy of Medical SciencesZhengzhou UniversityZhengzhou450052China
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6
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Galy B, Conrad M, Muckenthaler M. Mechanisms controlling cellular and systemic iron homeostasis. Nat Rev Mol Cell Biol 2024; 25:133-155. [PMID: 37783783 DOI: 10.1038/s41580-023-00648-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2023] [Indexed: 10/04/2023]
Abstract
In mammals, hundreds of proteins use iron in a multitude of cellular functions, including vital processes such as mitochondrial respiration, gene regulation and DNA synthesis or repair. Highly orchestrated regulatory systems control cellular and systemic iron fluxes ensuring sufficient iron delivery to target proteins is maintained, while limiting its potentially deleterious effects in iron-mediated oxidative cell damage and ferroptosis. In this Review, we discuss how cells acquire, traffick and export iron and how stored iron is mobilized for iron-sulfur cluster and haem biogenesis. Furthermore, we describe how these cellular processes are fine-tuned by the combination of various sensory and regulatory systems, such as the iron-regulatory protein (IRP)-iron-responsive element (IRE) network, the nuclear receptor co-activator 4 (NCOA4)-mediated ferritinophagy pathway, the prolyl hydroxylase domain (PHD)-hypoxia-inducible factor (HIF) axis or the nuclear factor erythroid 2-related factor 2 (NRF2) regulatory hub. We further describe how these pathways interact with systemic iron homeostasis control through the hepcidin-ferroportin axis to ensure appropriate iron fluxes. This knowledge is key for the identification of novel therapeutic opportunities to prevent diseases of cellular and/or systemic iron mismanagement.
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Affiliation(s)
- Bruno Galy
- German Cancer Research Center (DKFZ), Division of Virus-associated Carcinogenesis (F170), Heidelberg, Germany
| | - Marcus Conrad
- Helmholtz Zentrum München, Institute of Metabolism and Cell Death, Neuherberg, Germany
| | - Martina Muckenthaler
- Department of Paediatric Hematology, Oncology and Immunology, University of Heidelberg, Heidelberg, Germany.
- Molecular Medicine Partnership Unit, University of Heidelberg, Heidelberg, Germany.
- German Centre for Cardiovascular Research (DZHK), Partner site Heidelberg/Mannheim, Heidelberg, Germany.
- Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany.
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7
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Packer M. Mechanisms of enhanced renal and hepatic erythropoietin synthesis by sodium-glucose cotransporter 2 inhibitors. Eur Heart J 2023; 44:5027-5035. [PMID: 37086098 PMCID: PMC10733737 DOI: 10.1093/eurheartj/ehad235] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 03/06/2023] [Accepted: 04/03/2023] [Indexed: 04/23/2023] Open
Abstract
Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of major heart failure events, an action that is statistically linked to enhanced erythropoiesis, suggesting that stimulation of erythropoietin and cardioprotection are related to a shared mechanism. Four hypotheses have been proposed to explain how these drugs increase erythropoietin production: (i) renal cortical reoxygenation with rejuvenation of erythropoietin-producing cells; (ii) counterregulatory distal sodium reabsorption leading to increased tubular workload and oxygen consumption, and thus, to localized hypoxia; (iii) increased iron mobilization as a stimulus of hypoxia-inducible factor-2α (HIF-2α)-mediated erythropoietin synthesis; and (iv) direct HIF-2α activation and enhanced erythropoietin gene transcription due to increased sirtuin-1 (SIRT1) signaling. The first two hypotheses assume that the source of increased erythropoietin is the interstitial fibroblast-like cells in the deep renal cortex. However, SGLT2 inhibitors do not alter regional tissue oxygen tension in the non-diabetic kidney, and renal erythropoietin synthesis is markedly impaired in patients with anemia due to chronic kidney disease, and yet, SGLT2 inhibitors produce an unattenuated erythrocytic response in these patients. This observation raises the possibility that the liver contributes to the production of erythropoietin during SGLT2 inhibition. Hypoxia-inducible factor-2α and erythropoietin are coexpressed not only in the kidney but also in hepatocytes; the liver is a major site of production when erythropoietin stimulation is maintained for prolonged periods. The ability of SGLT2 inhibitors to improve iron mobilization by derepressing hepcidin and ferritin would be expected to increase cytosolic ferrous iron, which might stimulate HIF-2α expression in both the kidney and liver through the action of iron regulatory protein 1. Alternatively, the established ability of SGLT2 inhibitors to enhance SIRT1 might be the mechanism of enhanced erythropoietin production with these drugs. In hepatic cell lines, SIRT1 can directly activate HIF-2α by deacetylation, and additionally, through an effect of SIRT in the liver, peroxisome proliferator-activated receptor-γ coactivator-1α binds to hepatic nuclear factor 4 to promote transcription of the erythropoietin gene and synthesis of erythropoietin. Since SIRT1 up-regulation exerts direct cytoprotective effects on the heart and stimulates erythropoietin, it is well-positioned to represent the shared mechanism that links erythropoiesis to cardioprotection during SGLT2 inhibition.
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Affiliation(s)
- Milton Packer
- Baylor Heart and Vascular Institute, 621 North Hall Street, Dallas, TX 75226, USA
- Imperial College, London, UK
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Walter S, Mertens C, Muckenthaler MU, Ott C. Cardiac iron metabolism during aging - Role of inflammation and proteolysis. Mech Ageing Dev 2023; 215:111869. [PMID: 37678569 DOI: 10.1016/j.mad.2023.111869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 09/01/2023] [Accepted: 09/03/2023] [Indexed: 09/09/2023]
Abstract
Iron is the most abundant trace element in the human body. Since iron can switch between its 2-valent and 3-valent form it is essential in various physiological processes such as energy production, proliferation or DNA synthesis. Especially high metabolic organs such as the heart rely on iron-associated iron-sulfur and heme proteins. However, due to switches in iron oxidation state, iron overload exhibits high toxicity through formation of reactive oxygen species, underlining the importance of balanced iron levels. Growing evidence demonstrates disturbance of this balance during aging. While age-associated cardiovascular diseases are often related to iron deficiency, in physiological aging cardiac iron accumulates. To understand these changes, we focused on inflammation and proteolysis, two hallmarks of aging, and their role in iron metabolism. Via the IL-6-hepcidin axis, inflammation and iron status are strongly connected often resulting in anemia accompanied by infiltration of macrophages. This tight connection between anemia and inflammation highlights the importance of the macrophage iron metabolism during inflammation. Age-related decrease in proteolytic activity additionally affects iron balance due to impaired degradation of iron metabolism proteins. Therefore, this review accentuates alterations in iron metabolism during aging with regards to inflammation and proteolysis to draw attention to their implications and associations.
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Affiliation(s)
- Sophia Walter
- German Institute of Human Nutrition Potsdam-Rehbruecke, Department of Molecular Toxicology, Nuthetal, Germany; TraceAge-DFG Research Unit on Interactions of Essential Trace Elements in Healthy and Diseased Elderly, Potsdam-Berlin-Jena, Wuppertal, Germany; DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Christina Mertens
- Center for Translational Biomedical Iron Research, Department of Pediatric Oncology, Immunology, and Hematology, University of Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Heidelberg, Mannheim, Germany
| | - Martina U Muckenthaler
- Center for Translational Biomedical Iron Research, Department of Pediatric Oncology, Immunology, and Hematology, University of Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Heidelberg, Mannheim, Germany; Molecular Medicine Partnership Unit, Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), Heidelberg, Germany
| | - Christiane Ott
- German Institute of Human Nutrition Potsdam-Rehbruecke, Department of Molecular Toxicology, Nuthetal, Germany; TraceAge-DFG Research Unit on Interactions of Essential Trace Elements in Healthy and Diseased Elderly, Potsdam-Berlin-Jena, Wuppertal, Germany; DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany.
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9
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Hu CJ, Laux A, Gandjeva A, Wang L, Li M, Brown RD, Riddle S, Kheyfets VO, Tuder RM, Zhang H, Stenmark KR. The Effect of Hypoxia-inducible Factor Inhibition on the Phenotype of Fibroblasts in Human and Bovine Pulmonary Hypertension. Am J Respir Cell Mol Biol 2023; 69:73-86. [PMID: 36944195 PMCID: PMC10324042 DOI: 10.1165/rcmb.2022-0114oc] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 03/21/2023] [Indexed: 03/23/2023] Open
Abstract
Hypoxia-inducible factor (HIF) has received much attention as a potential pulmonary hypertension (PH) treatment target because inhibition of HIF reduces the severity of established PH in rodent models. However, the limitations of small-animal models of PH in predicting the therapeutic effects of pharmacologic interventions in humans PH are well known. Therefore, we sought to interrogate the role of HIFs in driving the activated phenotype of PH cells from human and bovine vessels. We first established that pulmonary arteries (PAs) from human and bovine PH lungs exhibit markedly increased expression of direct HIF target genes (CA9, GLUT1, and NDRG1), as well as cytokines/chemokines (CCL2, CSF2, CXCL12, and IL6), growth factors (FGF1, FGF2, PDGFb, and TGFA), and apoptosis-resistance genes (BCL2, BCL2L1, and BIRC5). The expression of the genes found in the intact PAs was determined in endothelial cells, smooth muscle cells, and fibroblasts cultured from the PAs. The data showed that human and bovine pulmonary vascular fibroblasts from patients or animals with PH (termed PH-Fibs) were the cell type that exhibited the highest level and the most significant increases in the expression of cytokines/chemokines and growth factors. In addition, we found that human, but not bovine, PH-Fibs exhibit consistent misregulation of HIFα protein stability, reduced HIF1α protein hydroxylation, and increased expression of HIF target genes even in cells grown under normoxic conditions. However, whereas HIF inhibition reduced the expression of direct HIF target genes, it had no impact on other "persistently activated" genes. Thus, our study indicated that HIF inhibition alone is not sufficient to reverse the persistently activated phenotype of human and bovine PH-Fibs.
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Affiliation(s)
- Cheng-Jun Hu
- Department of Craniofacial Biology, School of Dental Medicine, and
- Cardiovascular Pulmonary Research Laboratories, Departments of Pediatrics and Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Aya Laux
- Department of Craniofacial Biology, School of Dental Medicine, and
| | - Aneta Gandjeva
- Cardiovascular Pulmonary Research Laboratories, Departments of Pediatrics and Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Liyi Wang
- Department of Craniofacial Biology, School of Dental Medicine, and
| | - Min Li
- Cardiovascular Pulmonary Research Laboratories, Departments of Pediatrics and Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - R. Dale Brown
- Cardiovascular Pulmonary Research Laboratories, Departments of Pediatrics and Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Suzette Riddle
- Cardiovascular Pulmonary Research Laboratories, Departments of Pediatrics and Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Vitaly O. Kheyfets
- Cardiovascular Pulmonary Research Laboratories, Departments of Pediatrics and Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Rubin M. Tuder
- Cardiovascular Pulmonary Research Laboratories, Departments of Pediatrics and Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Hui Zhang
- Cardiovascular Pulmonary Research Laboratories, Departments of Pediatrics and Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Kurt R. Stenmark
- Cardiovascular Pulmonary Research Laboratories, Departments of Pediatrics and Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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Lee SJ, Jung C, Oh JE, Kim S, Lee S, Lee JY, Yoon YS. Generation of Red Blood Cells from Human Pluripotent Stem Cells-An Update. Cells 2023; 12:1554. [PMID: 37296674 PMCID: PMC10253210 DOI: 10.3390/cells12111554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 05/31/2023] [Accepted: 06/02/2023] [Indexed: 06/12/2023] Open
Abstract
Red blood cell (RBC) transfusion is a lifesaving medical procedure that can treat patients with anemia and hemoglobin disorders. However, the shortage of blood supply and risks of transfusion-transmitted infection and immune incompatibility present a challenge for transfusion. The in vitro generation of RBCs or erythrocytes holds great promise for transfusion medicine and novel cell-based therapies. While hematopoietic stem cells and progenitors derived from peripheral blood, cord blood, and bone marrow can give rise to erythrocytes, the use of human pluripotent stem cells (hPSCs) has also provided an important opportunity to obtain erythrocytes. These hPSCs include both human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs). As hESCs carry ethical and political controversies, hiPSCs can be a more universal source for RBC generation. In this review, we first discuss the key concepts and mechanisms of erythropoiesis. Thereafter, we summarize different methodologies to differentiate hPSCs into erythrocytes with an emphasis on the key features of human definitive erythroid lineage cells. Finally, we address the current limitations and future directions of clinical applications using hiPSC-derived erythrocytes.
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Affiliation(s)
- Shin-Jeong Lee
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; (S.-J.L.); (C.J.); (J.E.O.); (S.K.)
- Research and Development Center, KarisBio Inc., 50-1 Yonsei-Ro, Avison Biomedical Research Center Room 525, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Cholomi Jung
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; (S.-J.L.); (C.J.); (J.E.O.); (S.K.)
- Department of Internal Medicine, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Jee Eun Oh
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; (S.-J.L.); (C.J.); (J.E.O.); (S.K.)
- Research and Development Center, KarisBio Inc., 50-1 Yonsei-Ro, Avison Biomedical Research Center Room 525, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Sangsung Kim
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; (S.-J.L.); (C.J.); (J.E.O.); (S.K.)
- Research and Development Center, KarisBio Inc., 50-1 Yonsei-Ro, Avison Biomedical Research Center Room 525, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Sangho Lee
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA;
| | - Ji Yoon Lee
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; (S.-J.L.); (C.J.); (J.E.O.); (S.K.)
| | - Young-sup Yoon
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; (S.-J.L.); (C.J.); (J.E.O.); (S.K.)
- Research and Development Center, KarisBio Inc., 50-1 Yonsei-Ro, Avison Biomedical Research Center Room 525, Seodaemun-gu, Seoul 03722, Republic of Korea
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA;
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11
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Gangat N, Szuber N, Tefferi A. JAK2 unmutated erythrocytosis: 2023 Update on diagnosis and management. Am J Hematol 2023; 98:965-981. [PMID: 36966432 DOI: 10.1002/ajh.26920] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/18/2023] [Accepted: 03/22/2023] [Indexed: 03/27/2023]
Abstract
DISEASE OVERVIEW JAK2 unmutated or non-polycythemia vera (PV) erythrocytosis encompasses a heterogenous spectrum of hereditary and acquired entities. DIAGNOSIS Foremost in the evaluation of erythrocytosis is the exclusion of PV through JAK2 (inclusive of exons 12-15) mutation screening. Initial assessment should also include gathering of previous records on hematocrit (Hct) and hemoglobin (Hgb) levels, in order to streamline the diagnostic process by first distinguishing longstanding from acquired erythrocytosis; subsequent subcategorization is facilitated by serum erythropoietin (Epo) measurement, germline mutation screening, and review of historical data, including comorbid conditions and medication list. Hereditary erythrocytosis constitutes the main culprit in the context of longstanding erythrocytosis, especially when associated with a positive family history. In this regard, a subnormal serum Epo level suggests EPO receptor mutation. Otherwise, considerations include those associated with decreased (high oxygen affinity Hgb variants, 2,3-bisphosphoglycerate deficiency, PIEZO1 mutations, methemoglobinemia) or normal oxygen tension at 50% Hgb saturation (P50). The latter include germline oxygen sensing pathway (HIF2A-PHD2-VHL) and other rare mutations. Acquired erythrocytosis commonly results from central (e.g., cardiopulmonary disease, high-altitude habitat) or peripheral (e.g., renal artery stenosis) hypoxia. Other noteworthy conditions associated with acquired erythrocytosis include Epo-producing tumors (e.g., renal cell carcinoma, cerebral hemangioblastoma) and drugs (e.g., testosterone, erythropoiesis stimulating agents, sodium-glucose cotransporter-2 inhibitors). Idiopathic erythrocytosis is an ill-defined terminology that presumes the existence of an increased Hgb/Hct level without an identifiable etiology. Such classification often lacks accounting for normal outliers and is marred by truncated diagnostic evaluation. MANAGEMENT Current consensus treatment guidelines are not supported by hard evidence and their value is further undermined by limited phenotypic characterization and unfounded concerns for thrombosis. We are of the opinion that cytoreductive therapy and indiscriminate use of phlebotomy should be avoided in the treatment of non-clonal erythrocytosis. However, it is reasonable to consider therapeutic phlebotomy if one were to demonstrate value in symptom control, with frequency determined by symptoms rather than Hct level. In addition, cardiovascular risk optimization and low dose aspirin is often advised. FUTURE DIRECTIONS Advances in molecular hematology might result in better characterization of "idiopathic erythrocytosis" and expansion of the repertoire for germline mutations in hereditary erythrocytosis. Prospective controlled studies are needed to clarify potential pathology from JAK2 unmutated erythrocytosis, as well as to document the therapeutic value of phlebotomy.
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Affiliation(s)
- Naseema Gangat
- Division of Hematology, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Natasha Szuber
- Department of Hematology, Université de Montréal, Montréal, Quebec, Canada
| | - Ayalew Tefferi
- Division of Hematology, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota, USA
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12
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Myronenko O, Foris V, Crnkovic S, Olschewski A, Rocha S, Nicolls MR, Olschewski H. Endotyping COPD: hypoxia-inducible factor-2 as a molecular "switch" between the vascular and airway phenotypes? Eur Respir Rev 2023; 32:220173. [PMID: 36631133 PMCID: PMC9879331 DOI: 10.1183/16000617.0173-2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 11/08/2022] [Indexed: 01/13/2023] Open
Abstract
COPD is a heterogeneous disease with multiple clinical phenotypes. COPD endotypes can be determined by different expressions of hypoxia-inducible factors (HIFs), which, in combination with individual susceptibility and environmental factors, may cause predominant airway or vascular changes in the lung. The pulmonary vascular phenotype is relatively rare among COPD patients and characterised by out-of-proportion pulmonary hypertension (PH) and low diffusing capacity of the lung for carbon monoxide, but only mild-to-moderate airway obstruction. Its histologic feature, severe remodelling of the small pulmonary arteries, can be mediated by HIF-2 overexpression in experimental PH models. HIF-2 is not only involved in the vascular remodelling but also in the parenchyma destruction. Endothelial cells from human emphysema lungs express reduced HIF-2α levels, and the deletion of pulmonary endothelial Hif-2α leads to emphysema in mice. This means that both upregulation and downregulation of HIF-2 have adverse effects and that HIF-2 may represent a molecular "switch" between the development of the vascular and airway phenotypes in COPD. The mechanisms of HIF-2 dysregulation in the lung are only partly understood. HIF-2 levels may be controlled by NAD(P)H oxidases via iron- and redox-dependent mechanisms. A better understanding of these mechanisms may lead to the development of new therapeutic targets.
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Affiliation(s)
- Oleh Myronenko
- Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Vasile Foris
- Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
| | - Slaven Crnkovic
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
- Division of Physiology, Otto Loewi Research Center, Medical University of Graz, Graz, Austria
| | - Andrea Olschewski
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
- Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Graz, Austria
| | - Sonia Rocha
- Department of Molecular Physiology and Cell Signalling, Institute of Systems, Molecular, and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Mark R Nicolls
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Horst Olschewski
- Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
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13
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Liu Y, Li Y, Yang L, Shen J, Zhao H, Dong W, Chang Y, Qiao T, Li K. Stimulation of Hepatic Ferritinophagy Mitigates Irp2 Depletion-Induced Anemia. Antioxidants (Basel) 2023; 12:antiox12030566. [PMID: 36978814 PMCID: PMC10044941 DOI: 10.3390/antiox12030566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/13/2023] [Accepted: 02/16/2023] [Indexed: 03/02/2023] Open
Abstract
Background: Iron regulatory proteins (IRPs) maintain cellular iron homeostasis. Due to aberrant tissue-iron distribution, Irp2-deficient mice suffer microcytic anemia and neurodegeneration, while iron overload occurs in the liver and intestine. We previously found that Irp2 deficiency-induced Hif2 plays an important role in neurodegeneration. Methods: To test the role of Hif2 in Irp2 deficiency-induced anemia, we used Irp2 global knockout mice. Following Hif2 inhibition, routine blood tests, iron availability in bone marrow, histological assays, and biochemical analysis were performed to assess anemia improvement and tissue iron distribution. Results: We found that Hif2 inhibition improved anemia. The increased iron bioavailability for erythropoiesis was mainly derived from hepatic iron release, and secondly from enhanced intestinal absorption. We further demonstrate that nuclear receptor coactivator 4 (Ncoa4) was upregulated for iron release via the process of ferritinophagy. The released iron was utilized not only for intracellular Fe-S biogenesis but also for erythropoiesis after being exported from the liver to circulation. The hepatic iron export reduced hepcidin expression to further support iron absorption through the hepcidin-ferroportin axis to alleviate intestinal iron overload. Conclusion: Irp2 not only regulates cellular iron homeostasis but also tissue iron distribution by managing the involvement of Hif2-Ncoa4.
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Affiliation(s)
- Yutong Liu
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing 210093, China
- Department of Vascular Surgery, Affiliated Drum Tower Hospital, Medical School, Nanjing University, Nanjing 210093, China
| | - Yuxuan Li
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing 210093, China
| | - Liu Yang
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing 210093, China
| | - Jiaqi Shen
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing 210093, China
| | - Hongting Zhao
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing 210093, China
| | - Weichen Dong
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing 210093, China
- Department of Neurology, Affiliated Jinling Hospital, Medical School, Nanjing University, Nanjing 210002, China
| | - Yanzhong Chang
- College of Life Science, Hebei Normal University, Shijiazhuang 050024, China
| | - Tong Qiao
- Department of Vascular Surgery, Affiliated Drum Tower Hospital, Medical School, Nanjing University, Nanjing 210093, China
| | - Kuanyu Li
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing 210093, China
- Department of Vascular Surgery, Affiliated Drum Tower Hospital, Medical School, Nanjing University, Nanjing 210093, China
- Correspondence:
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14
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Clinical and Molecular Aspects of Iron Metabolism in Failing Myocytes. LIFE (BASEL, SWITZERLAND) 2022; 12:life12081203. [PMID: 36013382 PMCID: PMC9409945 DOI: 10.3390/life12081203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/15/2022] [Accepted: 07/22/2022] [Indexed: 11/16/2022]
Abstract
Heart failure (HF) is a common disease that causes significant limitations on the organism's capacity and, in extreme cases, leads to death. Clinically, iron deficiency (ID) plays an essential role in heart failure by deteriorating the patient's condition and is a prognostic marker indicating poor clinical outcomes. Therefore, in HF patients, supplementation of iron is recommended. However, iron treatment may cause adverse effects by increasing iron-related apoptosis and the production of oxygen radicals, which may cause additional heart damage. Furthermore, many knowledge gaps exist regarding the complex interplay between iron deficiency and heart failure. Here, we describe the current, comprehensive knowledge about the role of the proteins involved in iron metabolism. We will focus on the molecular and clinical aspects of iron deficiency in HF. We believe that summarizing the new advances in the translational and clinical research regarding iron deficiency in heart failure should broaden clinicians' awareness of this comorbidity.
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15
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The path from stem cells to red blood cells. Int J Hematol 2022; 116:160-162. [PMID: 35841459 DOI: 10.1007/s12185-022-03413-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 06/22/2022] [Accepted: 06/22/2022] [Indexed: 10/17/2022]
Abstract
As oxygen is essential for energy production in mitochondria, a sufficient amount of oxygen should be continuously delivered to the tissues to maintain life. Therefore, the number of red blood cells which carry the oxygen is considerable, at up to 25 trillion in the body, and 2 million new red blood cells are generated per second.
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16
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David S, Jhelum P, Ryan F, Jeong SY, Kroner A. Dysregulation of Iron Homeostasis in the Central Nervous System and the Role of Ferroptosis in Neurodegenerative Disorders. Antioxid Redox Signal 2022; 37:150-170. [PMID: 34569265 DOI: 10.1089/ars.2021.0218] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Significance: Iron accumulation occurs in the central nervous system (CNS) in a variety of neurological conditions as diverse as spinal cord injury, stroke, multiple sclerosis, Parkinson's disease, and others. Iron is a redox-active metal that gives rise to damaging free radicals if its intracellular levels are not controlled or if it is not properly sequestered within cells. The accumulation of iron occurs due to dysregulation of mechanisms that control cellular iron homeostasis. Recent Advances: The molecular mechanisms that regulate cellular iron homeostasis have been revealed in much detail in the past three decades, and new advances continue to be made. Understanding which aspects of iron homeostasis are dysregulated in different conditions will provide insights into the causes of iron accumulation and iron-mediated tissue damage. Recent advances in iron-dependent lipid peroxidation leading to cell death, called ferroptosis, has provided useful insights that are highly relevant for the lipid-rich environment of the CNS. Critical Issues: This review examines the mechanisms that control normal cellular iron homeostasis, the dysregulation of these mechanisms in neurological disorders, and more recent work on how iron can induce tissue damage via ferroptosis. Future Directions: Quick and reliable tests are needed to determine if and when ferroptosis contributes to the pathogenesis of neurological disorders. In addition, there is need to develop better druggable agents to scavenge lipid radicals and reduce CNS damage for neurological conditions for which there are currently few effective treatments. Antioxid. Redox Signal. 37, 150-170.
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Affiliation(s)
- Samuel David
- Centre for Research in Neuroscience, The Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Priya Jhelum
- Centre for Research in Neuroscience, The Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Fari Ryan
- Centre for Research in Neuroscience, The Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Suh Young Jeong
- Department of Molecular & Medical Genetics, Oregon Health & Science University, Portland, Oregon, USA
| | - Antje Kroner
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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17
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The mutual crosstalk between iron and erythropoiesis. Int J Hematol 2022; 116:182-191. [PMID: 35618957 DOI: 10.1007/s12185-022-03384-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 04/26/2022] [Accepted: 05/06/2022] [Indexed: 02/08/2023]
Abstract
Iron homeostasis and erythropoiesis are strongly interconnected. On one side iron is essential to terminal erythropoiesis for hemoglobin production, on the other erythropoiesis may increase iron absorption through the production of erythroferrone, the erythroid hormone that suppresses hepcidin expression Also erythropoietin production is modulated by iron through the iron regulatory proteins-iron responsive elements that control the hypoxia inducible factor 2-α. The second transferrin receptor, an iron sensor both in the liver and in erythroid cells modulates erythropoietin sensitivity and is a further link between hepcidin and erythropoiesis. When erythropoietin is decreased in iron deficiency the erythropoietin sensitivity is increased because the second transferrin receptor is removed from cell surface. A deranged balance between erythropoiesis and iron/hepcidin may lead to anemia, as in the case of iron deficiency, defective iron uptake and erythroid utilization or subnormal recycling. Defective control of hepcidin production may cause iron deficiency, as in the recessive disorder iron refractory iron deficiency anemia or in anemia of inflammation, or in iron loading anemias, which are characterized by excessive but ineffective erythropoiesis. The elucidation of the mechanisms that regulates iron homeostasis and erythropoiesis is leading to the development of drugs for the benefit of both iron and erythropoiesis disorders.
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18
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Abstract
Pulmonary hypertension (PH) describes heterogeneous population of patients with a mean pulmonary arterial pressure >20 mm Hg. Rarely, PH presents as a primary disorder but is more commonly part of a complex phenotype associated with comorbidities. Regardless of the cause, PH reduces life expectancy and impacts quality of life. The current clinical classification divides PH into 1 of 5 diagnostic groups to assign treatment. There are currently no pharmacological cures for any form of PH. Animal models are essential to help decipher the molecular mechanisms underlying the disease, to assign genotype-phenotype relationships to help identify new therapeutic targets, and for clinical translation to assess the mechanism of action and putative efficacy of new therapies. However, limitations inherent of all animal models of disease limit the ability of any single model to fully recapitulate complex human disease. Within the PH community, we are often critical of animal models due to the perceived low success upon clinical translation of new drugs. In this review, we describe the characteristics, advantages, and disadvantages of existing animal models developed to gain insight into the molecular and pathological mechanisms and test new therapeutics, focusing on adult forms of PH from groups 1 to 3. We also discuss areas of improvement for animal models with approaches combining several hits to better reflect the clinical situation and elevate their translational value.
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Affiliation(s)
- Olivier Boucherat
- Pulmonary Hypertension Research Group, Centre de Recherche de l’Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC, Canada
- Department of Medicine, Université Laval, Québec, QC, Canada
| | - Vineet Agrawal
- Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Allan Lawrie
- Dept of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK & Insigneo institute for in silico medicine, Sheffield, UK
| | - Sebastien Bonnet
- Pulmonary Hypertension Research Group, Centre de Recherche de l’Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC, Canada
- Department of Medicine, Université Laval, Québec, QC, Canada
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19
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Porras CA, Rouault TA. Iron Homeostasis in the CNS: An Overview of the Pathological Consequences of Iron Metabolism Disruption. Int J Mol Sci 2022; 23:ijms23094490. [PMID: 35562883 PMCID: PMC9104368 DOI: 10.3390/ijms23094490] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/14/2022] [Accepted: 04/17/2022] [Indexed: 11/21/2022] Open
Abstract
Iron homeostasis disruption has increasingly been implicated in various neurological disorders. In this review, we present an overview of our current understanding of iron metabolism in the central nervous system. We examine the consequences of both iron accumulation and deficiency in various disease contexts including neurodegenerative, neurodevelopmental, and neuropsychological disorders. The history of animal models of iron metabolism misregulation is also discussed followed by a comparison of three patients with a newly discovered neurodegenerative disorder caused by mutations in iron regulatory protein 2.
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20
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Saurage E, Davis PR, Meek R, Pollock DM, Kasztan M. Endothelin A receptor antagonist attenuated renal iron accumulation in iron overload heme oxygenase-1 knockout mice. Can J Physiol Pharmacol 2022; 100:637-650. [PMID: 35413222 PMCID: PMC10164438 DOI: 10.1139/cjpp-2022-0038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Progressive iron accumulation and renal impairment are prominent in both patients and mouse models of sickle cell disease (SCD). Endothelin A receptor (ETA) antagonism prevents this iron accumulation phenotype and reduces renal iron deposition in proximal tubules of SCD mice. To better understand the mechanisms of iron metabolism in the kidney and the role of ETA receptor in iron chelation and transport, we studied renal iron handling in a non-sickle cell iron overload model, heme oxygenase-1 (Hmox-1-/-) knockout mice. We found that Hmox-1-/- mice had elevated plasma endothelin-1 (ET-1), cortical ET-1 mRNA expression, and renal iron content compared to Hmox-1+/+ controls. The ETA receptor antagonist, ambrisentan, attenuated renal iron deposition, without any changes to anemia status in Hmox-1-/- mice. This was accompanied by reduced urinary iron excretion. Finally, ambrisentan had an important iron recycling effect by increasing expression of cellular iron exporter, ferroportin-1 (FPN-1) and circulating total iron levels in Hmox-1-/- mice. These findings suggest the ET-1/ETA signaling pathway contributes to in renal iron trafficking in a murine model of iron overload.
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Affiliation(s)
- Elizabeth Saurage
- The University of Alabama at Birmingham School of Medicine, 9967, Medicine, Division of Nephrology, Birmingham, Alabama, United States;
| | - Parker Ross Davis
- The University of Alabama at Birmingham Department of Medicine, 164494, Medicine, Division of Nephrology, Birmingham, Alabama, United States;
| | - Rachel Meek
- The University of Alabama at Birmingham School of Medicine, 9967, Medicine, Devision of Nephrology, Birmingham, Alabama, United States;
| | - David M Pollock
- The University of Alabama at Birmingham Department of Medicine, 164494, Medicine, Division of Nephrology, Birmingham, Alabama, United States;
| | - Malgorzata Kasztan
- The University of Alabama at Birmingham School of Medicine, 9967, Pediatrics, Division of Hematology-Oncology, Birmingham, Alabama, United States;
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21
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Liang S, Yegambaram M, Wang T, Wang J, Black SM, Tang H. Mitochondrial Metabolism, Redox, and Calcium Homeostasis in Pulmonary Arterial Hypertension. Biomedicines 2022; 10:biomedicines10020341. [PMID: 35203550 PMCID: PMC8961787 DOI: 10.3390/biomedicines10020341] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/25/2022] [Accepted: 01/26/2022] [Indexed: 02/06/2023] Open
Abstract
Pulmonary arterial hypertension (PAH) is a progressive disease characterized by elevated pulmonary arterial pressure due to increased pulmonary vascular resistance, secondary to sustained pulmonary vasoconstriction and excessive obliterative pulmonary vascular remodeling. Work over the last decade has led to the identification of a critical role for metabolic reprogramming in the PAH pathogenesis. It is becoming clear that in addition to its role in ATP generation, the mitochondrion is an important organelle that regulates complex and integrative metabolic- and signal transduction pathways. This review focuses on mitochondrial metabolism alterations that occur in deranged pulmonary vessels and the right ventricle, including abnormalities in glycolysis and glucose oxidation, fatty acid oxidation, glutaminolysis, redox homeostasis, as well as iron and calcium metabolism. Further understanding of these mitochondrial metabolic mechanisms could provide viable therapeutic approaches for PAH patients.
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Affiliation(s)
- Shuxin Liang
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangdong Key Laboratory of Vascular Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China; (S.L.); (J.W.)
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Manivannan Yegambaram
- Center for Translational Science, 11350 SW Village Pkwy, Port St. Lucie, FL 34987, USA; (M.Y.); (T.W.)
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Port St. Lucie, FL 34987, USA
| | - Ting Wang
- Center for Translational Science, 11350 SW Village Pkwy, Port St. Lucie, FL 34987, USA; (M.Y.); (T.W.)
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Port St. Lucie, FL 34987, USA
| | - Jian Wang
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangdong Key Laboratory of Vascular Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China; (S.L.); (J.W.)
| | - Stephen M. Black
- Center for Translational Science, 11350 SW Village Pkwy, Port St. Lucie, FL 34987, USA; (M.Y.); (T.W.)
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Port St. Lucie, FL 34987, USA
- Department of Cellular Biology & Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Port St. Lucie, FL 34987, USA
- Correspondence: (S.M.B.); (H.T.)
| | - Haiyang Tang
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangdong Key Laboratory of Vascular Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China; (S.L.); (J.W.)
- Correspondence: (S.M.B.); (H.T.)
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22
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Votava JA, Reese SR, Deck KM, Nizzi CP, Anderson SA, Djamali A, Eisenstein RS. Dysregulation of the sensory and regulatory pathways controlling cellular iron metabolism in unilateral obstructive nephropathy. Am J Physiol Renal Physiol 2022; 322:F89-F103. [PMID: 34843656 PMCID: PMC8742730 DOI: 10.1152/ajprenal.00537.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/16/2021] [Accepted: 11/23/2021] [Indexed: 01/03/2023] Open
Abstract
Chronic kidney disease involves disturbances in iron metabolism including anemia caused by insufficient erythropoietin (EPO) production. However, underlying mechanisms responsible for the dysregulation of cellular iron metabolism are incompletely defined. Using the unilateral ureteral obstruction (UUO) model in Irp1+/+ and Irp1-/- mice, we asked if iron regulatory proteins (IRPs), the central regulators of cellular iron metabolism and suppressors of EPO production, contribute to the etiology of anemia in kidney failure. We identified a significant reduction in IRP protein level and RNA binding activity that associates with a loss of the iron uptake protein transferrin receptor 1 (TfR1), increased expression of the iron storage protein subunits H- and L-ferritin, and a low but overall variable level of stainable iron in the obstructed kidney. This reduction in IRP RNA binding activity and ferritin RNA levels suggests the concomitant rise in ferritin expression and iron content in kidney failure is IRP dependent. In contrast, the reduction in the Epo mRNA level in the obstructed kidney was not rescued by genetic ablation of IRP1, suggesting disruption of normal hypoxia-inducible factor (HIF)-2α regulation. Furthermore, reduced expression of some HIF-α target genes in UUO occurred in the face of increased expression of HIF-α proteins and prolyl hydroxylases 2 and 1, the latter of which is not known to be HIF-α mediated. Our results suggest that the IRP system drives changes in cellular iron metabolism that are associated with kidney failure in UUO but that the impact of IRPs on EPO production is overridden by disrupted hypoxia signaling.NEW & NOTEWORTHY This study demonstrates that iron metabolism and hypoxia signaling are dysregulated in unilateral obstructive nephropathy. Expression of iron regulatory proteins (IRPs), central regulators of cellular iron metabolism, and the iron uptake (transferrin receptor 1) and storage (ferritins) proteins they target is strongly altered. This suggests a role of IRPs in previously observed changes in iron metabolism in progressive renal disease. Hypoxia signaling is disrupted and appeared to dominate the action of IRP1 in controlling erythropoietin expression.
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Affiliation(s)
- James A Votava
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin
| | - Shannon R Reese
- Division of Nephrology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Kathryn M Deck
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin
| | - Christopher P Nizzi
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin
| | - Sheila A Anderson
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin
| | - Arjang Djamali
- Division of Nephrology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
- Division of Transplant, Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin
| | - Richard S Eisenstein
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin
- Morgridge Institute for Research, University of Wisconsin-Madison, Madison, Wisconsin
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23
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Rethinking IRPs/IRE system in neurodegenerative disorders: Looking beyond iron metabolism. Ageing Res Rev 2022; 73:101511. [PMID: 34767973 DOI: 10.1016/j.arr.2021.101511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/21/2021] [Accepted: 11/04/2021] [Indexed: 12/11/2022]
Abstract
Iron regulatory proteins (IRPs) and iron regulatory element (IRE) systems are well known in the progression of neurodegenerative disorders by regulating iron related proteins. IRPs are also regulated by iron homeostasis. However, an increasing number of studies have suggested a close relationship between the IRPs/IRE system and non-iron-related neurodegenerative disorders. In this paper, we reviewed that the IRPs/IRE system is not only controlled by iron ions, but also regulated by such factors as post-translational modification, oxygen, nitric oxide (NO), heme, interleukin-1 (IL-1), and metal ions. In addition, by regulating the transcription of non-iron related proteins, the IRPs/IRE system functioned in oxidative metabolism, cell cycle regulation, abnormal proteins aggregation, and neuroinflammation. Finally, by emphasizing the multiple regulations of IRPs/IRE system and its potential relationship with non-iron metabolic neurodegenerative disorders, we provided new strategies for disease treatment targeting IRPs/IRE system.
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Shen J, Xu L, Li Y, Dong W, Cai J, Liu Y, Zhao H, Xu T, Holtz EM, Chang Y, Qiao T, Li K. Protective Effects of Hif2 Inhibitor PT-2385 on a Neurological Disorder Induced by Deficiency of Irp2. Front Neurosci 2021; 15:715222. [PMID: 34675764 PMCID: PMC8525628 DOI: 10.3389/fnins.2021.715222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 09/06/2021] [Indexed: 12/30/2022] Open
Abstract
Iron regulatory protein 2 (IRP2) deficiency in mice and humans causes microcytic anemia and neurodegeneration due to functional cellular iron depletion. Our previous in vitro data have demonstrated that Irp2 depletion upregulates hypoxia-inducible factor subunits Hif1α and Hif2α expression; inhibition of Hif2α rescues Irp2 ablation-induced mitochondrial dysfunction; and inhibition of Hif1α suppresses the overdose production of lactic acid derived from actively aerobic glycolysis. We wonder whether Hif1α and Hif2α are also elevated in vivo and play a similar role in neurological disorder of Irp2–/– mice. In this study, we confirmed the upregulation of Hif2α, not Hif1α, in tissues, particularly in the central nervous system including the mainly affected cerebellum and spinal cord of Irp2–/– mice. Consistent with this observation, inhibition of Hif2α by PT-2385, not Hif1α by PX-478, prevented neurodegenerative symptoms, which were proved by Purkinje cell arrangement from the shrunken and irregular to the full and regular array. PT-2385 treatment did not only modulate mitochondrial morphology and quality in vivo but also suppressed glycolysis. Consequently, the shift of energy metabolism from glycolysis to oxidative phosphorylation (OXPHOS) was reversed. Our results indicate that Irp2 depletion-induced Hif2α is, in vivo, in charge of the switch between OXPHOS and glycolysis, suggesting that, for the first time to our knowledge, Hif2α is a clinically potential target in the treatment of IRP2 deficiency-induced neurodegenerative syndrome.
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Affiliation(s)
- Jiaqi Shen
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, China
| | - Li Xu
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, China
| | - Yuxuan Li
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, China
| | - Weichen Dong
- Department of Neurology, The Affiliated Jinling Hospital of Nanjing University Medical School, Nanjing, China
| | - Jing Cai
- Department of Vascular Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China
| | - Yutong Liu
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, China
| | - Hongting Zhao
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, China
| | - Tianze Xu
- Department of Vascular Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China
| | - Esther Meyron Holtz
- The Laboratory of Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa, Israel
| | - Yanzhong Chang
- College of Life Science, Hebei Normal University, Shijiazhuang, China
| | - Tong Qiao
- Department of Vascular Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China
| | - Kuanyu Li
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, China
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Essential role of systemic iron mobilization and redistribution for adaptive thermogenesis through HIF2-α/hepcidin axis. Proc Natl Acad Sci U S A 2021; 118:2109186118. [PMID: 34593646 DOI: 10.1073/pnas.2109186118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2021] [Indexed: 12/23/2022] Open
Abstract
Iron is an essential biometal, but is toxic if it exists in excess. Therefore, iron content is tightly regulated at cellular and systemic levels to meet metabolic demands but to avoid toxicity. We have recently reported that adaptive thermogenesis, a critical metabolic pathway to maintain whole-body energy homeostasis, is an iron-demanding process for rapid biogenesis of mitochondria. However, little information is available on iron mobilization from storage sites to thermogenic fat. This study aimed to determine the iron-regulatory network that underlies beige adipogenesis. We hypothesized that thermogenic stimulus initiates the signaling interplay between adipocyte iron demands and systemic iron liberation, resulting in iron redistribution into beige fat. To test this hypothesis, we induced reversible activation of beige adipogenesis in C57BL/6 mice by administering a β3-adrenoreceptor agonist CL 316,243 (CL). Our results revealed that CL stimulation induced the iron-regulatory protein-mediated iron import into adipocytes, suppressed hepcidin transcription, and mobilized iron from the spleen. Mechanistically, CL stimulation induced an acute activation of hypoxia-inducible factor 2-α (HIF2-α), erythropoietin production, and splenic erythroid maturation, leading to hepcidin suppression. Disruption of systemic iron homeostasis by pharmacological HIF2-α inhibitor PT2385 or exogenous administration of hepcidin-25 significantly impaired beige fat development. Our findings suggest that securing iron availability via coordinated interplay between renal hypoxia and hepcidin down-regulation is a fundamental mechanism to activate adaptive thermogenesis. It also provides an insight into the effects of adaptive thermogenesis on systemic iron mobilization and redistribution.
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Liu X, Shi B, Suo R, Xiong S, Wang X, Liang X, Li X, Li G. Itaconate regulates macrophage function through stressful iron-sulfur cluster disrupting and iron metabolism rebalancing. FASEB J 2021; 35:e21936. [PMID: 34547129 DOI: 10.1096/fj.202100726rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 11/11/2022]
Abstract
Lipopolysaccharide (LPS)-stimulated macrophages express an aconitate decarboxylase (IRG1, also called ACOD1), leading to accumulation of the endogenous metabolite itaconate. However, the precise mechanisms by which elevated itaconate levels alter macrophage function are not clear. Our hypothesis is itaconate affects macrophage function through some uncertain mechanism. Based on this, we established a transcriptional and proteomic signature of macrophages stimulated by itaconate and identified the pathways of IL-1β secretion and altered iron metabolism. Consistently, the effect of IRG1 deficiency on IL-1β secretion and iron metabolism was confirmed in IRG1 knockout THP-1 cell lines. Several common inhibitors and other compounds were used to examine the molecular mechanisms involved. Only cysteine and antioxidants (catechin hydrate) could inhibit caspase-1 activation and IL-1β secretion in itaconate-stimulated macrophages. We further found that aconitase activity was decreased by itaconate stimulation. Our results demonstrate the counteracting effects of overexpression of mitochondrial aconitase (ACO2, a tricarboxylic acid cycle enzyme) or cytosolic aconitase (ACO1, an iron regulatory protein) on IL-1β secretion and altered iron metabolism. Both enzyme activities were inhibited by itaconate because of iron-sulfur (Fe-S) cluster destruction. Our findings indicate that the immunoregulatory functions of IRG1 and itaconate in macrophages are stressful Fe-S cluster of aconitases disrupting and iron metabolism rebalancing.
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Affiliation(s)
- Xing Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Bingshuo Shi
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Rong Suo
- Department of Cardiology, Tianjin Hospital, Tianjin, China
| | - Shenglin Xiong
- Department of Cardiology, You Country People's Hospital, Zhuzhou, China
| | - Xuewen Wang
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Xue Liang
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Xinjian Li
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Guangping Li
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, The Second Hospital of Tianjin Medical University, Tianjin, China
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Edwards DF, Miller CJ, Quintana‐Martinez A, Wright CS, Prideaux M, Atkins GJ, Thompson WR, Clinkenbeard EL. Differential Iron Requirements for Osteoblast and Adipocyte Differentiation. JBMR Plus 2021; 5:e10529. [PMID: 34532614 PMCID: PMC8441506 DOI: 10.1002/jbm4.10529] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 05/24/2021] [Accepted: 06/27/2021] [Indexed: 12/17/2022] Open
Abstract
Bone marrow mesenchymal progenitor cells are precursors for various cell types including osteoblasts, adipocytes, and chondrocytes. The external environment and signals act to direct the pathway of differentiation. Importantly, situations such as aging and chronic kidney disease display alterations in the balance of osteoblast and adipocyte differentiation, adversely affecting bone integrity. Iron deficiency, which can often occur during aging and chronic kidney disease, is associated with reduced bone density. The purpose of this study was to assess the effects of iron deficiency on the capacity of progenitor cell differentiation pathways. Mouse and human progenitor cells, differentiated under standard osteoblast and adipocyte protocols in the presence of the iron chelator deferoxamine (DFO), were used. Under osteogenic conditions, 5μM DFO significantly impaired expression of critical osteoblast genes, including osteocalcin, type 1 collagen, and dentin matrix protein 1. This led to a reduction in alkaline phosphatase activity and impaired mineralization. Despite prolonged exposure to chronic iron deficiency, cells retained viability as well as normal hypoxic responses with significant increases in transferrin receptor and protein accumulation of hypoxia inducible factor 1α. Similar concentrations of DFO were used when cells were maintained in adipogenic conditions. In contrast to osteoblast differentiation, DFO modestly suppressed adipocyte gene expression of peroxisome-proliferating activated receptor gamma, lipoprotein lipase, and adiponectin at earlier time points with normalization at later stages. Lipid accumulation was also similar in all conditions. These data suggest the critical importance of iron in osteoblast differentiation, and as long as the external stimuli are present, iron deficiency does not impede adipogenesis. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Daniel F. Edwards
- Department of Medical and Molecular GeneticsSchool of Medicine, Indiana UniversityIndianapolisINUSA
| | - Christopher J. Miller
- Department of Medical and Molecular GeneticsSchool of Medicine, Indiana UniversityIndianapolisINUSA
| | - Arelis Quintana‐Martinez
- Department of Medical and Molecular GeneticsSchool of Medicine, Indiana UniversityIndianapolisINUSA
| | - Christian S. Wright
- Department of Physical TherapySchool of Health & Human Sciences, Indiana UniversityIndianapolisINUSA
| | - Matthew Prideaux
- Indiana Center for Musculoskeletal HealthIndiana UniversityIndianapolisINUSA
| | - Gerald J. Atkins
- Centre for Orthopaedic & Trauma ResearchUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - William R. Thompson
- Department of Physical TherapySchool of Health & Human Sciences, Indiana UniversityIndianapolisINUSA
| | - Erica L. Clinkenbeard
- Department of Medical and Molecular GeneticsSchool of Medicine, Indiana UniversityIndianapolisINUSA
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Lucero García Rojas EY, Villanueva C, Bond RA. Hypoxia Inducible Factors as Central Players in the Pathogenesis and Pathophysiology of Cardiovascular Diseases. Front Cardiovasc Med 2021; 8:709509. [PMID: 34447792 PMCID: PMC8382733 DOI: 10.3389/fcvm.2021.709509] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 07/09/2021] [Indexed: 01/01/2023] Open
Abstract
Cardiovascular (CV) diseases are the major cause of death in industrialized countries. The main function of the CV system is to deliver nutrients and oxygen to all tissues. During most CV pathologies, oxygen and nutrient delivery is decreased or completely halted. Several mechanisms, including increased oxygen transport and delivery, as well as increased blood flow are triggered to compensate for the hypoxic state. If the compensatory mechanisms fail to sufficiently correct the hypoxia, irreversible damage can occur. Thus, hypoxia plays a central role in the pathogenesis and pathophysiology of CV diseases. Hypoxia inducible factors (HIFs) orchestrate the gene transcription for hundreds of proteins involved in erythropoiesis, glucose transport, angiogenesis, glycolytic metabolism, reactive oxygen species (ROS) handling, cell proliferation and survival, among others. The overall regulation of the expression of HIF-dependent genes depends on the severity, duration, and location of hypoxia. In the present review, common CV diseases were selected to illustrate that HIFs, and proteins derived directly or indirectly from their stabilization and activation, are related to the development and perpetuation of hypoxia in these pathologies. We further classify CV diseases into acute and chronic hypoxic states to better understand the temporal relevance of HIFs in the pathogenesis, disease progression and clinical outcomes of these diseases. We conclude that HIFs and their derived factors are fundamental in the genesis and progression of CV diseases. Understanding these mechanisms will lead to more effective treatment strategies leading to reduced morbidity and mortality.
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Affiliation(s)
| | - Cleva Villanueva
- Instituto Politecnico Nacional, Escuela Superior de Medicina, Mexico City, Mexico
| | - Richard A Bond
- Department of Pharmacology and Pharmaceutical Sciences, University of Houston, Houston, TX, United States
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Duarte TL, Talbot NP, Drakesmith H. NRF2 and Hypoxia-Inducible Factors: Key Players in the Redox Control of Systemic Iron Homeostasis. Antioxid Redox Signal 2021; 35:433-452. [PMID: 32791852 DOI: 10.1089/ars.2020.8148] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Significance: Oxygen metabolism and iron homeostasis are closely linked. Iron facilitates the oxygen-carrying capacity of blood, and its deficiency causes anemia. Conversely, excess free iron is detrimental for stimulating the formation of reactive oxygen species, causing tissue damage. The amount and distribution of iron thus need to be tightly regulated by the liver-expressed hormone hepcidin. This review analyzes the roles of key oxygen-sensing pathways in cellular and systemic regulation of iron homeostasis; specifically, the prolyl hydroxylase domain (PHD)/hypoxia-inducible factor (HIF) and the Kelch-like ECH-associated protein 1/NF-E2 p45-related factor 2 (KEAP1/NRF2) pathways, which mediate tissue adaptation to low and high oxygen, respectively. Recent Advances: In macrophages, NRF2 regulates genes involved in hemoglobin catabolism, iron storage, and iron export. NRF2 was recently identified as the molecular sensor of iron-induced oxidative stress and is responsible for BMP6 expression by liver sinusoidal endothelial cells, which in turn activates hepcidin synthesis by hepatocytes to restore systemic iron levels. Moreover, NRF2 orchestrates the activation of antioxidant defenses that are crucial to protect against iron toxicity. On the contrary, low iron/hypoxia stabilizes renal HIF2a via inactivation of iron-dependent PHD dioxygenases, causing an erythropoietic stimulus that represses hepcidin via an inhibitory effect of erythroferrone on bone morphogenetic proteins. Intestinal HIF2a is also stabilized, increasing the expression of genes involved in dietary iron absorption. Critical Issues: An intimate crosstalk between oxygen-sensing pathways and iron regulatory mechanisms ensures that fluctuations in systemic iron levels are promptly detected and restored. Future Directions: The realization that redox-sensitive transcription factors regulate systemic iron levels suggests novel therapeutic approaches. Antioxid. Redox Signal. 35, 433-452.
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Affiliation(s)
- Tiago L Duarte
- Instituto de Biologia Molecular e Celular, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
| | - Nick P Talbot
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, United Kingdom
| | - Hal Drakesmith
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
- Haematology Theme, Oxford Biomedical Research Centre, Oxford, United Kingdom
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Breakthrough Science: Hypoxia-Inducible Factors, Oxygen Sensing, and Disorders of Hematopoiesis. Blood 2021; 139:2441-2449. [PMID: 34411243 DOI: 10.1182/blood.2021011043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 07/28/2021] [Indexed: 11/20/2022] Open
Abstract
Hypoxia-inducible factors (HIF) were discovered as activators of erythropoietin gene transcription in response to reduced O2 availability. O2-dependent hydroxylation of HIFs on proline and asparagine residues regulates protein stability and transcription activity, respectively. Mutations in genes encoding components of the oxygen sensing pathway cause familial erythrocytosis. Several small molecule inhibitors of HIF prolyl hydroxylases are currently in clinical trials as erythropoiesis stimulating agents. HIFs are overexpressed in bone marrow neoplasms, and the development of HIF inhibitors may improve outcome in these disorders.
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31
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Maio N, Zhang DL, Ghosh MC, Jain A, SantaMaria AM, Rouault TA. Mechanisms of cellular iron sensing, regulation of erythropoiesis and mitochondrial iron utilization. Semin Hematol 2021; 58:161-174. [PMID: 34389108 DOI: 10.1053/j.seminhematol.2021.06.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 06/08/2021] [Accepted: 06/10/2021] [Indexed: 12/11/2022]
Abstract
To maintain an adequate iron supply for hemoglobin synthesis and essential metabolic functions while counteracting iron toxicity, humans and other vertebrates have evolved effective mechanisms to conserve and finely regulate iron concentration, storage, and distribution to tissues. At the systemic level, the iron-regulatory hormone hepcidin is secreted by the liver in response to serum iron levels and inflammation. Hepcidin regulates the expression of the sole known mammalian iron exporter, ferroportin, to control dietary absorption, storage and tissue distribution of iron. At the cellular level, iron regulatory proteins 1 and 2 (IRP1 and IRP2) register cytosolic iron concentrations and post-transcriptionally regulate the expression of iron metabolism genes to optimize iron availability for essential cellular processes, including heme biosynthesis and iron-sulfur cluster biogenesis. Genetic malfunctions affecting the iron sensing mechanisms or the main pathways that utilize iron in the cell cause a broad range of human diseases, some of which are characterized by mitochondrial iron accumulation. This review will discuss the mechanisms of systemic and cellular iron sensing with a focus on the main iron utilization pathways in the cell, and on human conditions that arise from compromised function of the regulatory axes that control iron homeostasis.
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Affiliation(s)
- Nunziata Maio
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - De-Liang Zhang
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Manik C Ghosh
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Anshika Jain
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Anna M SantaMaria
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Tracey A Rouault
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD.
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Silvestri L, Nai A. Iron and erythropoiesis: A mutual alliance. Semin Hematol 2021; 58:145-152. [PMID: 34389106 DOI: 10.1053/j.seminhematol.2021.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/26/2021] [Accepted: 05/31/2021] [Indexed: 02/07/2023]
Abstract
The large amount of iron required for hemoglobin synthesis keeps iron homeostasis and erythropoiesis inter-connected, both iron levels being affected by increased erythropoiesis, and erythropoiesis regulated by serum iron. The connection between these 2 processes is maintained even when erythropoiesis is ineffective. In the last years great advances in the understanding of the mechanisms of this crosstalk have been achieved thanks to the discovery of 2 essential players: hepcidin, the master regulator of iron homeostasis, and erythroferrone, the long sought erythroid regulator. In addition, how circulating transferrin-bound iron contributes to the crosstalk between the 2 systems has started to be unraveled.
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Affiliation(s)
- Laura Silvestri
- Regulation of Iron Metabolism Unit-Div. Genetics & Cell Biology-IRCCS San Raffaele Scientific Institute, Milano, Italy; San Raffaele Vita-Salute University, Milano, Italy.
| | - Antonella Nai
- Regulation of Iron Metabolism Unit-Div. Genetics & Cell Biology-IRCCS San Raffaele Scientific Institute, Milano, Italy; San Raffaele Vita-Salute University, Milano, Italy
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Ghosh MC, Zhang DL, Ollivierre WH, Noguchi A, Springer DA, Linehan WM, Rouault TA. Therapeutic inhibition of HIF-2α reverses polycythemia and pulmonary hypertension in murine models of human diseases. Blood 2021; 137:2509-2519. [PMID: 33512384 PMCID: PMC8109019 DOI: 10.1182/blood.2020009138] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/04/2020] [Indexed: 12/20/2022] Open
Abstract
Polycythemia and pulmonary hypertension are 2 human diseases for which better therapies are needed. Upregulation of hypoxia-inducible factor-2α (HIF-2α) and its target genes, erythropoietin (EPO) and endothelin-1, causes polycythemia and pulmonary hypertension in patients with Chuvash polycythemia who are homozygous for the R200W mutation in the von Hippel Lindau (VHL) gene and in a murine mouse model of Chuvash polycythemia that bears the same homozygous VhlR200W mutation. Moreover, the aged VhlR200W mice developed pulmonary fibrosis, most likely due to the increased expression of Cxcl-12, another Hif-2α target. Patients with mutations in iron regulatory protein 1 (IRP1) also develop polycythemia, and Irp1-knockout (Irp1-KO) mice exhibit polycythemia, pulmonary hypertension, and cardiac fibrosis attributable to translational derepression of Hif-2α, and the resultant high expression of the Hif-2α targets EPO, endothelin-1, and Cxcl-12. In this study, we inactivated Hif-2α with the second-generation allosteric HIF-2α inhibitor MK-6482 in VhlR200W, Irp1-KO, and double-mutant VhlR200W;Irp1-KO mice. MK-6482 treatment decreased EPO production and reversed polycythemia in all 3 mouse models. Drug treatment also decreased right ventricular pressure and mitigated pulmonary hypertension in VhlR200W, Irp1-KO, and VhlR200W;Irp1-KO mice to near normal wild-type levels and normalized the movement of the cardiac interventricular septum in VhlR200Wmice. MK-6482 treatment reduced the increased expression of Cxcl-12, which, in association with CXCR4, mediates fibrocyte influx into the lungs, potentially causing pulmonary fibrosis. Our results suggest that oral intake of MK-6482 could represent a new approach to treatment of patients with polycythemia, pulmonary hypertension, pulmonary fibrosis, and complications caused by elevated expression of HIF-2α.
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Affiliation(s)
- Manik C Ghosh
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development
| | - De-Liang Zhang
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development
| | - Wade H Ollivierre
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development
| | - Audrey Noguchi
- Murine Phenotyping Core, National Heart, Lung, and Blood Institute, and
| | | | - W Marston Linehan
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Tracey A Rouault
- Molecular Medicine Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development
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Nutritional immunity: the impact of metals on lung immune cells and the airway microbiome during chronic respiratory disease. Respir Res 2021; 22:133. [PMID: 33926483 PMCID: PMC8082489 DOI: 10.1186/s12931-021-01722-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 04/15/2021] [Indexed: 12/15/2022] Open
Abstract
Nutritional immunity is the sequestration of bioavailable trace metals such as iron, zinc and copper by the host to limit pathogenicity by invading microorganisms. As one of the most conserved activities of the innate immune system, limiting the availability of free trace metals by cells of the immune system serves not only to conceal these vital nutrients from invading bacteria but also operates to tightly regulate host immune cell responses and function. In the setting of chronic lung disease, the regulation of trace metals by the host is often disrupted, leading to the altered availability of these nutrients to commensal and invading opportunistic pathogenic microbes. Similarly, alterations in the uptake, secretion, turnover and redox activity of these vitally important metals has significant repercussions for immune cell function including the response to and resolution of infection. This review will discuss the intricate role of nutritional immunity in host immune cells of the lung and how changes in this fundamental process as a result of chronic lung disease may alter the airway microbiome, disease progression and the response to infection.
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36
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Iron control of erythroid microtubule cytoskeleton as a potential target in treatment of iron-restricted anemia. Nat Commun 2021; 12:1645. [PMID: 33712594 PMCID: PMC7955080 DOI: 10.1038/s41467-021-21938-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 02/20/2021] [Indexed: 12/17/2022] Open
Abstract
Anemias of chronic disease and inflammation (ACDI) result from restricted iron delivery to erythroid progenitors. The current studies reveal an organellar response in erythroid iron restriction consisting of disassembly of the microtubule cytoskeleton and associated Golgi disruption. Isocitrate supplementation, known to abrogate the erythroid iron restriction response, induces reassembly of microtubules and Golgi in iron deprived progenitors. Ferritin, based on proteomic profiles, regulation by iron and isocitrate, and putative interaction with microtubules, is assessed as a candidate mediator. Knockdown of ferritin heavy chain (FTH1) in iron replete progenitors induces microtubule collapse and erythropoietic blockade; conversely, enforced ferritin expression rescues erythroid differentiation under conditions of iron restriction. Fumarate, a known ferritin inducer, synergizes with isocitrate in reversing molecular and cellular defects of iron restriction and in oral remediation of murine anemia. These findings identify a cytoskeletal component of erythroid iron restriction and demonstrate potential for its therapeutic targeting in ACDI. Debilitating anemias in chronic diseases can result from deficient iron delivery to red cell precursors. Here, the authors show how this deficiency damages the cytoskeletal framework of progenitor cells and identify a targeted strategy for cytoskeletal repair, leading to anemia correction.
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Iron Deficiency in Pulmonary Arterial Hypertension: A Deep Dive into the Mechanisms. Cells 2021; 10:cells10020477. [PMID: 33672218 PMCID: PMC7926484 DOI: 10.3390/cells10020477] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 02/13/2021] [Accepted: 02/18/2021] [Indexed: 02/06/2023] Open
Abstract
Pulmonary arterial hypertension (PAH) is a severe cardiovascular disease that is caused by the progressive occlusion of the distal pulmonary arteries, eventually leading to right heart failure and death. Almost 40% of patients with PAH are iron deficient. Although widely studied, the mechanisms linking between PAH and iron deficiency remain unclear. Here we review the mechanisms regulating iron homeostasis and the preclinical and clinical data available on iron deficiency in PAH. Then we discuss the potential implications of iron deficiency on the development and management of PAH.
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Pullamsetti SS, Mamazhakypov A, Weissmann N, Seeger W, Savai R. Hypoxia-inducible factor signaling in pulmonary hypertension. J Clin Invest 2021; 130:5638-5651. [PMID: 32881714 DOI: 10.1172/jci137558] [Citation(s) in RCA: 94] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Pulmonary hypertension (PH) is characterized by pulmonary artery remodeling that can subsequently culminate in right heart failure and premature death. Emerging evidence suggests that hypoxia-inducible factor (HIF) signaling plays a fundamental and pivotal role in the pathogenesis of PH. This Review summarizes the regulation of HIF isoforms and their impact in various PH subtypes, as well as the elaborate conditional and cell-specific knockout mouse studies that brought the role of this pathway to light. We also discuss the current preclinical status of pan- and isoform-selective HIF inhibitors, and propose new research areas that may facilitate HIF isoform-specific inhibition as a novel therapeutic strategy for PH and right heart failure.
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Affiliation(s)
- Soni Savai Pullamsetti
- Department of Lung Development and Remodeling, Max Planck Institute for Heart and Lung Research, member of the German Center for Lung Research (DZL), member of the Cardio-Pulmonary Institute (CPI), Bad Nauheim, Germany.,Department of Internal Medicine, Universities of Giessen and Marburg Lung Center, member of the DZL and CPI, Justus Liebig University, Giessen, Germany
| | - Argen Mamazhakypov
- Department of Lung Development and Remodeling, Max Planck Institute for Heart and Lung Research, member of the German Center for Lung Research (DZL), member of the Cardio-Pulmonary Institute (CPI), Bad Nauheim, Germany
| | - Norbert Weissmann
- Department of Internal Medicine, Universities of Giessen and Marburg Lung Center, member of the DZL and CPI, Justus Liebig University, Giessen, Germany
| | - Werner Seeger
- Department of Lung Development and Remodeling, Max Planck Institute for Heart and Lung Research, member of the German Center for Lung Research (DZL), member of the Cardio-Pulmonary Institute (CPI), Bad Nauheim, Germany.,Department of Internal Medicine, Universities of Giessen and Marburg Lung Center, member of the DZL and CPI, Justus Liebig University, Giessen, Germany.,Institute for Lung Health (ILH), Justus Liebig University, Giessen, Germany
| | - Rajkumar Savai
- Department of Lung Development and Remodeling, Max Planck Institute for Heart and Lung Research, member of the German Center for Lung Research (DZL), member of the Cardio-Pulmonary Institute (CPI), Bad Nauheim, Germany.,Department of Internal Medicine, Universities of Giessen and Marburg Lung Center, member of the DZL and CPI, Justus Liebig University, Giessen, Germany.,Institute for Lung Health (ILH), Justus Liebig University, Giessen, Germany.,Frankfurt Cancer Institute (FCI), Goethe University, Frankfurt am Main, Germany
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Pulmonary Hypertension in Acute and Chronic High Altitude Maladaptation Disorders. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18041692. [PMID: 33578749 PMCID: PMC7916528 DOI: 10.3390/ijerph18041692] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/05/2021] [Accepted: 02/07/2021] [Indexed: 12/13/2022]
Abstract
Alveolar hypoxia is the most prominent feature of high altitude environment with well-known consequences for the cardio-pulmonary system, including development of pulmonary hypertension. Pulmonary hypertension due to an exaggerated hypoxic pulmonary vasoconstriction contributes to high altitude pulmonary edema (HAPE), a life-threatening disorder, occurring at high altitudes in non-acclimatized healthy individuals. Despite a strong physiologic rationale for using vasodilators for prevention and treatment of HAPE, no systematic studies of their efficacy have been conducted to date. Calcium-channel blockers are currently recommended for drug prophylaxis in high-risk individuals with a clear history of recurrent HAPE based on the extensive clinical experience with nifedipine in HAPE prevention in susceptible individuals. Chronic exposure to hypoxia induces pulmonary vascular remodeling and development of pulmonary hypertension, which places an increased pressure load on the right ventricle leading to right heart failure. Further, pulmonary hypertension along with excessive erythrocytosis may complicate chronic mountain sickness, another high altitude maladaptation disorder. Importantly, other causes than hypoxia may potentially underlie and/or contribute to pulmonary hypertension at high altitude, such as chronic heart and lung diseases, thrombotic or embolic diseases. Extensive clinical experience with drugs in patients with pulmonary arterial hypertension suggests their potential for treatment of high altitude pulmonary hypertension. Small studies have demonstrated their efficacy in reducing pulmonary artery pressure in high altitude residents. However, no drugs have been approved to date for the therapy of chronic high altitude pulmonary hypertension. This work provides a literature review on the role of pulmonary hypertension in the pathogenesis of acute and chronic high altitude maladaptation disorders and summarizes current knowledge regarding potential treatment options.
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Mleczko‐Sanecka K, Silvestri L. Cell-type-specific insights into iron regulatory processes. Am J Hematol 2021; 96:110-127. [PMID: 32945012 DOI: 10.1002/ajh.26001] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 08/20/2020] [Accepted: 09/14/2020] [Indexed: 12/16/2022]
Abstract
Despite its essential role in many biological processes, iron is toxic when in excess due to its propensity to generate reactive oxygen species. To prevent diseases associated with iron deficiency or iron loading, iron homeostasis must be tightly controlled. Intracellular iron content is regulated by the Iron Regulatory Element-Iron Regulatory Protein (IRE-IRP) system, whereas systemic iron availability is adjusted to body iron needs chiefly by the hepcidin-ferroportin (FPN) axis. Here, we aimed to review advances in the field that shed light on cell-type-specific regulatory mechanisms that control or modify systemic and local iron balance, and how shifts in cellular iron levels may affect specialized cell functions.
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Affiliation(s)
| | - Laura Silvestri
- Regulation of Iron Metabolism Unit, Division of Genetics and Cell Biology IRCCS San Raffaele Scientific Institute Milan Italy
- Vita‐Salute San Raffaele University Milan Italy
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41
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Gangat N, Szuber N, Pardanani A, Tefferi A. JAK2 unmutated erythrocytosis: current diagnostic approach and therapeutic views. Leukemia 2021; 35:2166-2181. [PMID: 34021251 PMCID: PMC8324477 DOI: 10.1038/s41375-021-01290-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/28/2021] [Accepted: 05/06/2021] [Indexed: 02/08/2023]
Abstract
JAK2 unmutated or non-polycythemia vera (PV) erythrocytosis encompasses both hereditary and acquired conditions. A systematic diagnostic approach begins with documentation of historical hematocrit (Hct)/hemoglobin (Hgb) measurements and classification of the process as life-long/unknown duration or acquired. Further investigation in both categories is facilitated by determination of serum erythropoietin level (EPO). Workup for hereditary/congenital erythrocytosis requires documentation of family history and laboratory screening for high-oxygen affinity hemoglobin variants, 2, 3 biphosphoglycerate deficiency, and germline mutations that are known to alter cellular oxygen sensing (e.g., PHD2, HIF2A, VHL) or EPO signaling (e.g., EPOR mutations); the latter is uniquely associated with subnormal EPO. Acquired erythrocytosis is often elicited by central or peripheral hypoxia resulting from cardiopulmonary disease/high-altitude dwelling or renal artery stenosis, respectively; EPO in the former instance is often normal (compensated by negative feed-back). Other conditions associated with acquired erythrocytosis include EPO-producing tumors and the use of drugs that promote erythropoiesis (e.g., testosterone, erythropoiesis stimulating agents). "Idiopathic erythrocytosis" loosely refers to an otherwise not explained situation. Historically, management of non-PV erythrocytosis has been conflicted by unfounded concerns regarding thrombosis risk, stemming from limited phenotypic characterization, save for Chuvash polycythemia, well-known for its thrombotic tendency. In general, cytoreductive therapy should be avoided and phlebotomy is seldom warranted where frequency is determined by symptom control rather than Hct threshold. Although not supported by hard evidence, cardiovascular risk optimization and low-dose aspirin use are often advised. Application of modern genetic tests and development of controlled therapeutic intervention trials are needed to advance current clinical practice.
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Affiliation(s)
- Naseema Gangat
- grid.66875.3a0000 0004 0459 167XDivision of Hematology, Department of Internal Medicine, Mayo Clinic, Rochester, MN USA
| | - Natasha Szuber
- grid.14848.310000 0001 2292 3357Department of Hematology, Université de Montréal, Montréal, QC Canada
| | - Animesh Pardanani
- grid.66875.3a0000 0004 0459 167XDivision of Hematology, Department of Internal Medicine, Mayo Clinic, Rochester, MN USA
| | - Ayalew Tefferi
- grid.66875.3a0000 0004 0459 167XDivision of Hematology, Department of Internal Medicine, Mayo Clinic, Rochester, MN USA
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Garza KR, Clarke SL, Ho YH, Bruss MD, Vasanthakumar A, Anderson SA, Eisenstein RS. Differential translational control of 5' IRE-containing mRNA in response to dietary iron deficiency and acute iron overload. Metallomics 2020; 12:2186-2198. [PMID: 33325950 DOI: 10.1039/d0mt00192a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Iron regulatory proteins (IRPs) are iron-responsive RNA binding proteins that dictate changes in cellular iron metabolism in animal cells by controlling the fate of mRNAs containing iron responsive elements (IREs). IRPs have broader physiological roles as some targeted mRNAs encode proteins with functions beyond iron metabolism suggesting hierarchical regulation of IRP-targeted mRNAs. We observe that the translational regulation of IRP-targeted mRNAs encoding iron storage (L- and H-ferritins) and export (ferroportin) proteins have different set-points of iron responsiveness compared to that for the TCA cycle enzyme mitochondrial aconitase. The ferritins and ferroportin mRNA were largely translationally repressed in the liver of rats fed a normal diet whereas mitochondrial aconitase mRNA is primarily polysome bound. Consequently, acute iron overload increases polysome association of H- and L-ferritin and ferroportin mRNAs while mitochondrial aconitase mRNA showed little stimulation. Conversely, mitochondrial aconitase mRNA is most responsive in iron deficiency. These differences in regulation were associated with a faster off-rate of IRP1 for the IRE of mitochondrial aconitase in comparison to that of L-ferritin. Thus, hierarchical control of mRNA translation by IRPs involves selective control of cellular functions acting at different states of cellular iron status and that are critical for adaptations to iron deficiency or prevention of iron toxicity.
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Affiliation(s)
- Kerry R Garza
- University of Wisconsin-Madison, Department of Nutritional Sciences, 1415 Linden Drive, Madison, WI 53706, USA.
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43
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Valente de Souza L, Hoffmann A, Weiss G. Impact of bacterial infections on erythropoiesis. Expert Rev Anti Infect Ther 2020; 19:619-633. [PMID: 33092423 DOI: 10.1080/14787210.2021.1841636] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION The importance of iron is highlighted by the many complex metabolic pathways in which it is involved. A sufficient supply is essential for the effective production of 200 billion erythrocytes daily, a process called erythropoiesis. AREAS COVERED During infection, the human body can withhold iron from pathogens, mechanism termed nutritional immunity. The subsequent disturbances in iron homeostasis not only impact on immune function and infection control, but also negatively affect erythropoiesis. The complex interplay between iron, immunity, erythropoiesis and infection control on the molecular and clinical level are highlighted in this review. Diagnostic algorithms for correct interpretation and diagnosis of the iron status in the setting of infection are presented. Therapeutic concepts are discussed regarding effects on anemia correction, but also toward their role on the course of infection. EXPERT OPINION In the setting of infection, anemia is often neglected and its impact on the course of diseases is incompletely understood. Clinical expertise can be improved in correct diagnosing of anemia and disturbances of iron homeostasis. Systemic studies are needed to evaluate the impact of specific therapeutic interventions on anemia correction on the course of infection, but also on patients' cardiovascular performance and quality of life.
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Affiliation(s)
- Lara Valente de Souza
- Department of Internal Medicine II, Infectious Diseases, Immunology, Rheumatology, Medical University ofI nnsbruck, Innsbruck, Austria.,Christian Doppler Laboratory for Iron Metabolism and Anemia Research, Medical University of Innsbruck, Innsbruck, Austria
| | - Alexander Hoffmann
- Department of Internal Medicine II, Infectious Diseases, Immunology, Rheumatology, Medical University ofI nnsbruck, Innsbruck, Austria.,Christian Doppler Laboratory for Iron Metabolism and Anemia Research, Medical University of Innsbruck, Innsbruck, Austria
| | - Günter Weiss
- Department of Internal Medicine II, Infectious Diseases, Immunology, Rheumatology, Medical University ofI nnsbruck, Innsbruck, Austria.,Christian Doppler Laboratory for Iron Metabolism and Anemia Research, Medical University of Innsbruck, Innsbruck, Austria
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Abstract
The TEMPI syndrome is a rare and acquired disorder characterized by 5 salient features, which compose its name: (1) telangiectasias; (2) elevated erythropoietin and erythrocytosis; (3) monoclonal gammopathy; (4) perinephric fluid collections; and (5) intrapulmonary shunting. Complete resolution of symptoms following treatment with plasma cell-directed therapy supports the hypothesis that the monoclonal antibody is causal and pathogenic. Understanding the basis of the TEMPI syndrome will depend on the identification of additional patients and a coordinated international effort.
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45
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Fillebeen C, Lam NH, Chow S, Botta A, Sweeney G, Pantopoulos K. Regulatory Connections between Iron and Glucose Metabolism. Int J Mol Sci 2020; 21:ijms21207773. [PMID: 33096618 PMCID: PMC7589414 DOI: 10.3390/ijms21207773] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/07/2020] [Accepted: 10/16/2020] [Indexed: 02/06/2023] Open
Abstract
Iron is essential for energy metabolism, and states of iron deficiency or excess are detrimental for organisms and cells. Therefore, iron and carbohydrate metabolism are tightly regulated. Serum iron and glucose levels are subjected to hormonal regulation by hepcidin and insulin, respectively. Hepcidin is a liver-derived peptide hormone that inactivates the iron exporter ferroportin in target cells, thereby limiting iron efflux to the bloodstream. Insulin is a protein hormone secreted from pancreatic β-cells that stimulates glucose uptake and metabolism via insulin receptor signaling. There is increasing evidence that systemic, but also cellular iron and glucose metabolic pathways are interconnected. This review article presents relevant data derived primarily from mouse models and biochemical studies. In addition, it discusses iron and glucose metabolism in the context of human disease.
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Affiliation(s)
- Carine Fillebeen
- Lady Davis Institute for Medical Research, Jewish General Hospital and Department of Medicine, McGill University, Montreal, QC H3Y 1P3, Canada;
| | - Nhat Hung Lam
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada; (N.H.L.); (S.C.); (A.B.); (G.S.)
| | - Samantha Chow
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada; (N.H.L.); (S.C.); (A.B.); (G.S.)
| | - Amy Botta
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada; (N.H.L.); (S.C.); (A.B.); (G.S.)
| | - Gary Sweeney
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada; (N.H.L.); (S.C.); (A.B.); (G.S.)
| | - Kostas Pantopoulos
- Lady Davis Institute for Medical Research, Jewish General Hospital and Department of Medicine, McGill University, Montreal, QC H3Y 1P3, Canada;
- Correspondence: ; Tel.: +1-514-340-8260 (ext. 25293)
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46
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Altamura S, Marques O, Colucci S, Mertens C, Alikhanyan K, Muckenthaler MU. Regulation of iron homeostasis: Lessons from mouse models. Mol Aspects Med 2020; 75:100872. [DOI: 10.1016/j.mam.2020.100872] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 06/28/2020] [Accepted: 07/02/2020] [Indexed: 12/13/2022]
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Iron-responsive-like elements and neurodegenerative ferroptosis. ACTA ACUST UNITED AC 2020; 27:395-413. [PMID: 32817306 PMCID: PMC7433652 DOI: 10.1101/lm.052282.120] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 07/02/2020] [Indexed: 12/26/2022]
Abstract
A set of common-acting iron-responsive 5′untranslated region (5′UTR) motifs can fold into RNA stem loops that appear significant to the biology of cognitive declines of Parkinson's disease dementia (PDD), Lewy body dementia (LDD), and Alzheimer's disease (AD). Neurodegenerative diseases exhibit perturbations of iron homeostasis in defined brain subregions over characteristic time intervals of progression. While misfolding of Aβ from the amyloid-precursor-protein (APP), alpha-synuclein, prion protein (PrP) each cause neuropathic protein inclusions in the brain subregions, iron-responsive-like element (IRE-like) RNA stem–loops reside in their transcripts. APP and αsyn have a role in iron transport while gene duplications elevate the expression of their products to cause rare familial cases of AD and PDD. Of note, IRE-like sequences are responsive to excesses of brain iron in a potential feedback loop to accelerate neuronal ferroptosis and cognitive declines as well as amyloidosis. This pathogenic feedback is consistent with the translational control of the iron storage protein ferritin. We discuss how the IRE-like RNA motifs in the 5′UTRs of APP, alpha-synuclein and PrP mRNAs represent uniquely folded drug targets for therapies to prevent perturbed iron homeostasis that accelerates AD, PD, PD dementia (PDD) and Lewy body dementia, thus preventing cognitive deficits. Inhibition of alpha-synuclein translation is an option to block manganese toxicity associated with early childhood cognitive problems and manganism while Pb toxicity is epigenetically associated with attention deficit and later-stage AD. Pathologies of heavy metal toxicity centered on an embargo of iron export may be treated with activators of APP and ferritin and inhibitors of alpha-synuclein translation.
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48
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Sonnweber T, Pizzini A, Tancevski I, Löffler-Ragg J, Weiss G. Anaemia, iron homeostasis and pulmonary hypertension: a review. Intern Emerg Med 2020; 15:573-585. [PMID: 32040829 PMCID: PMC7289779 DOI: 10.1007/s11739-020-02288-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/28/2020] [Indexed: 02/08/2023]
Abstract
Anaemia is a highly prevalent condition, which negatively impacts on patients' cardiovascular performance and quality of life. Anaemia is mainly caused by disturbances of iron homeostasis. While absolute iron deficiency mostly as a consequence of chronic blood loss or insufficient dietary iron absorption results in the emergence of iron deficiency anaemia, inflammation-driven iron retention in innate immune cells and blockade of iron absorption leads to the development of anaemia of chronic disease. Both, iron deficiency and anaemia have been linked to the clinical course of pulmonary hypertension. Various mechanistic links between iron homeostasis, anaemia, and pulmonary hypertension have been described and current treatment guidelines suggest regular iron status assessment and the implementation of iron supplementation strategies in these patients. The pathophysiology, diagnostic assessment as well as current and future treatment options concerning iron deficiency with or without anaemia in individuals suffering from pulmonary hypertension are discussed within this review.
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Affiliation(s)
- Thomas Sonnweber
- Department of Internal Medicine II, Medical University Innsbruck, Innsbruck, Austria
| | - Alex Pizzini
- Department of Internal Medicine II, Medical University Innsbruck, Innsbruck, Austria
| | - Ivan Tancevski
- Department of Internal Medicine II, Medical University Innsbruck, Innsbruck, Austria
| | - Judith Löffler-Ragg
- Department of Internal Medicine II, Medical University Innsbruck, Innsbruck, Austria
| | - Günter Weiss
- Department of Internal Medicine II, Medical University Innsbruck, Innsbruck, Austria.
- Christian Doppler Laboratory for Iron Metabolism and Anaemia Research, Medical University Innsbruck, Innsbruck, Austria.
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49
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Oskarsson GR, Oddsson A, Magnusson MK, Kristjansson RP, Halldorsson GH, Ferkingstad E, Zink F, Helgadottir A, Ivarsdottir EV, Arnadottir GA, Jensson BO, Katrinardottir H, Sveinbjornsson G, Kristinsdottir AM, Lee AL, Saemundsdottir J, Stefansdottir L, Sigurdsson JK, Davidsson OB, Benonisdottir S, Jonasdottir A, Jonasdottir A, Jonsson S, Gudmundsson RL, Asselbergs FW, Tragante V, Gunnarsson B, Masson G, Thorleifsson G, Rafnar T, Holm H, Olafsson I, Onundarson PT, Gudbjartsson DF, Norddahl GL, Thorsteinsdottir U, Sulem P, Stefansson K. Predicted loss and gain of function mutations in ACO1 are associated with erythropoiesis. Commun Biol 2020; 3:189. [PMID: 32327693 PMCID: PMC7181819 DOI: 10.1038/s42003-020-0921-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 03/24/2020] [Indexed: 12/28/2022] Open
Abstract
Hemoglobin is the essential oxygen-carrying molecule in humans and is regulated by cellular iron and oxygen sensing mechanisms. To search for novel variants associated with hemoglobin concentration, we performed genome-wide association studies of hemoglobin concentration using a combined set of 684,122 individuals from Iceland and the UK. Notably, we found seven novel variants, six rare coding and one common, at the ACO1 locus associating with either decreased or increased hemoglobin concentration. Of these variants, the missense Cys506Ser and the stop-gained Lys334Ter mutations are specific to eight and ten generation pedigrees, respectively, and have the two largest effects in the study (EffectCys506Ser = -1.61 SD, CI95 = [-1.98, -1.35]; EffectLys334Ter = 0.63 SD, CI95 = [0.36, 0.91]). We also find Cys506Ser to associate with increased risk of persistent anemia (OR = 17.1, P = 2 × 10-14). The strong bidirectional effects seen in this study implicate ACO1, a known iron sensing molecule, as a major homeostatic regulator of hemoglobin concentration.
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Affiliation(s)
- Gudjon R Oskarsson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
| | | | - Magnus K Magnusson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
| | | | | | | | | | | | | | | | | | | | | | | | - Amy L Lee
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
| | | | | | | | | | | | | | | | | | | | - Folkert W Asselbergs
- Department of Cardiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- Institute of Cardiovascular Science, Faculty of Population Health Sciences, University College London, London, UK
- Health Data Research UK and Institute of Health Informatics, University College London, London, UK
| | - Vinicius Tragante
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Department of Cardiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | | | | | | | | | - Hilma Holm
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
| | - Isleifur Olafsson
- Department of Clinical Biochemistry, Landspitali, the National University Hospital of Iceland, Reykjavik, Iceland
| | - Pall T Onundarson
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
- Department of Laboratory Hematology, Landspitali, the National University Hospital of Iceland, Reykjavik, Iceland
| | - Daniel F Gudbjartsson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- School of Engineering and Natural Sciences, University of Iceland, Reykjavik, Iceland
| | | | - Unnur Thorsteinsdottir
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
| | | | - Kari Stefansson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland.
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland.
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50
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Zhang Y, Feng X, Zhang J, Chen X. Iron Regulatory Protein 2 Exerts its Oncogenic Activities by Suppressing TAp63 Expression. Mol Cancer Res 2020; 18:1039-1049. [PMID: 32276991 DOI: 10.1158/1541-7786.mcr-19-1104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/19/2020] [Accepted: 04/07/2020] [Indexed: 12/15/2022]
Abstract
Iron regulatory protein 2 (IRP2) is a key regulator of iron homeostasis and is found to be altered in several types of human cancer. However, how IRP2 contributes to tumorigenesis remains to be elucidated. In this study, we sought to investigate the role of IRP2 in tumorigenesis and found that IRP2 promotes cell growth by repressing TAp63, a member of p53 tumor suppressor family. Specifically, we found that IRP2 overexpression decreased, whereas IRP2 deficiency increased, TAp63 expression. We also showed that the repression of TAp63 by IRP2 was independent of tumor suppressor p53. To uncover the molecular basis, we found that IRP2 stabilized TAp63 mRNA by binding to an iron response element in the 3'UTR of p63 mRNA. To determine the biological significance of this regulation, we showed that IRP2 facilitates cell proliferation, at least in part, via repressing TAp63 expression. Moreover, we found that IRP2 deficiency markedly alleviated cellular senescence in TAp63-deficient mouse embryo fibroblasts. Together, we have uncovered a novel regulation of TAp63 by IRP2 and our data suggest that IRP2 exerts its oncogenic activities at least in part by repressing TAp63 expression. IMPLICATIONS: We have revealed a novel regulation of TAp63 by IRP2 and our data suggest that IRP2 exerts its oncogenic activities, at least in part, by repressing TAp63 expression.
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Affiliation(s)
- Yanhong Zhang
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, Davis, California
| | - Xiuli Feng
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, Davis, California
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Jin Zhang
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, Davis, California
| | - Xinbin Chen
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, Davis, California.
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