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Zhang T, Liu Q, Chen Q, Wu H. Iron regulatory protein two facilitates ferritinophagy and DNA damage/repair through guiding ATG9A trafficking. J Biol Chem 2024; 300:107767. [PMID: 39276939 DOI: 10.1016/j.jbc.2024.107767] [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: 03/23/2024] [Revised: 07/17/2024] [Accepted: 08/25/2024] [Indexed: 09/17/2024] Open
Abstract
Trace elemental iron is an essential nutrient that participates in diverse metabolic processes. Dysregulation of cellular iron homeostasis, both iron deficiency and iron overload, is detrimental and tightly associated with disease pathogenesis. IRPs-IREs system is located at the center for iron homeostasis regulation. Additionally, ferritinophagy, the autophagy-dependent ferritin catabolism for iron recycling, is emerging as a novel mechanism for iron homeostasis regulation. It is still unclear whether IRPs-IREs system and ferritinophagy are synergistic or redundant in determining iron homeostasis. Here we report that IRP2, but not IRP1, is indispensable for ferritinophagy in response to iron depletion. Mechanistically, IRP2 ablation results in compromised AMPK activation and defective ATG9A endosomal trafficking, leading to the decreased engulfment of NCOA4-ferritin complex by endosomes and the subsequent dysregulated endosomal microferritinophagy. Moreover, this defective endosomal microferritinophagy exacerbates DNA damage and reduces colony formation in IRP2-depleted cells. Collectively, this study expands the physiological function of IRP2 in endosomal microferritinophagy and highlights potential crosstalk between IRPs-IREs and ferritinophagy in manipulating iron homeostasis.
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Affiliation(s)
- Ting Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China; Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Qian Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China; Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Quan Chen
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Hao Wu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China; Hubei Hongshan Laboratory, Wuhan, Hubei, China.
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2
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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: 110] [Impact Index Per Article: 110.0] [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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3
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Hinokuma H, Kanamori Y, Ikeda K, Hao L, Maruno M, Yamane T, Maeda A, Nita A, Shimoda M, Niimura M, Takeshima Y, Li S, Suzuki M, Moroishi T. Distinct functions between ferrous and ferric iron in lung cancer cell growth. Cancer Sci 2023; 114:4355-4364. [PMID: 37688294 PMCID: PMC10637068 DOI: 10.1111/cas.15949] [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: 05/10/2023] [Revised: 08/19/2023] [Accepted: 08/21/2023] [Indexed: 09/10/2023] Open
Abstract
Accumulating evidence suggests an association between iron metabolism and lung cancer progression. In biological systems, iron is present in either reduced (Fe2+ ; ferrous) or oxidized (Fe3+ ; ferric) states. However, ferrous and ferric iron exhibit distinct chemical and biological properties, the role of ferrous and ferric iron in lung cancer cell growth has not been clearly distinguished. In this study, we manipulated the balance between cellular ferrous and ferric iron status by inducing gene mutations involving the FBXL5-IRP2 axis, a ubiquitin-dependent regulatory system for cellular iron homeostasis, and determined its effects on lung cancer cell growth. FBXL5 depletion (ferrous iron accumulation) was found to suppress lung cancer cell growth, whereas IRP2 depletion (ferric iron accumulation) did not suppress such growth, suggesting that ferrous iron but not ferric iron plays a suppressive role in cell growth. Mechanistically, the depletion of FBXL5 impaired the degradation of the cyclin-dependent kinase inhibitor, p27, resulting in a delay in the cell cycle at the G1/S phase. FBXL5 depletion in lung cancer cells also improved the survival of tumor-bearing mice. Overall, this study highlights the important function of ferrous iron in cell cycle progression and lung cancer cell growth.
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Affiliation(s)
- Hironori Hinokuma
- Department of Molecular and Medical Pharmacology, Faculty of Life SciencesKumamoto UniversityKumamotoJapan
- Department of Thoracic and Breast Surgery, Graduate School of Medical SciencesKumamoto UniversityKumamotoJapan
| | - Yohei Kanamori
- Department of Molecular and Medical Pharmacology, Faculty of Life SciencesKumamoto UniversityKumamotoJapan
| | - Koei Ikeda
- Department of Thoracic and Breast Surgery, Graduate School of Medical SciencesKumamoto UniversityKumamotoJapan
| | - Li Hao
- Department of Molecular and Medical Pharmacology, Faculty of Life SciencesKumamoto UniversityKumamotoJapan
| | - Masataka Maruno
- Department of Molecular and Medical Pharmacology, Faculty of Life SciencesKumamoto UniversityKumamotoJapan
| | - Taishi Yamane
- Department of Molecular and Medical Pharmacology, Faculty of Life SciencesKumamoto UniversityKumamotoJapan
| | - Ayato Maeda
- Department of Molecular and Medical Pharmacology, Faculty of Life SciencesKumamoto UniversityKumamotoJapan
| | - Akihiro Nita
- Department of Molecular and Medical Pharmacology, Faculty of Life SciencesKumamoto UniversityKumamotoJapan
| | - Mayuko Shimoda
- Department of Molecular and Medical Pharmacology, Faculty of Life SciencesKumamoto UniversityKumamotoJapan
| | - Mayumi Niimura
- Department of Molecular and Medical Pharmacology, Faculty of Life SciencesKumamoto UniversityKumamotoJapan
| | - Yuki Takeshima
- Department of Molecular and Medical Pharmacology, Faculty of Life SciencesKumamoto UniversityKumamotoJapan
| | - Shuran Li
- Department of Molecular and Medical Pharmacology, Faculty of Life SciencesKumamoto UniversityKumamotoJapan
| | - Makoto Suzuki
- Department of Thoracic and Breast Surgery, Graduate School of Medical SciencesKumamoto UniversityKumamotoJapan
| | - Toshiro Moroishi
- Department of Molecular and Medical Pharmacology, Faculty of Life SciencesKumamoto UniversityKumamotoJapan
- Center for Metabolic Regulation of Healthy Aging, Faculty of Life SciencesKumamoto UniversityKumamotoJapan
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4
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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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5
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Zhou H, Chen J, Fan M, Cai H, Dong Y, Qiu Y, Zhuang Q, Lei Z, Li M, Ding X, Yan P, Lin A, Zheng S, Yan Q. KLF14 regulates the growth of hepatocellular carcinoma cells via its modulation of iron homeostasis through the repression of iron-responsive element-binding protein 2. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2023; 42:5. [PMID: 36600258 DOI: 10.1186/s13046-022-02562-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 12/06/2022] [Indexed: 01/06/2023]
Abstract
BACKGROUND Hepatocellular carcinoma (HCC) is a multifactor-driven malignant tumor with rapid progression, which causes the difficulty to substantially improve the prognosis of HCC. Limited understanding of the mechanisms in HCC impedes the development of efficacious therapies. Despite Krüpple-Like factors (KLFs) were reported to be participated in HCC pathogenesis, the function of KLF14 in HCC remains largely unexplored. METHODS We generated KLF14 overexpressed and silenced liver cancer cells, and nude mouse xenograft models for the in vitro and in vivo study. Luciferase reporter assay, ChIP-qPCR, Co-IP, immunofluorescence were performed for mechanism research. The expression of KLF14 in HCC samples was analyzed by quantitative RT-PCR, Western blotting, and immunohistochemistry (IHC) analysis. RESULTS KLF14 was significantly downregulated in human HCC tissues, which was highly correlated with poor prognosis. Inhibition of KLF14 promoted liver cancer cells proliferation and overexpression of KLF14 suppressed cells growth. KLF14 exerts its anti-tumor function by inhibiting Iron-responsive element-binding protein 2 (IRP2), which then causes transferrin receptor-1(TfR1) downregulation and ferritin upregulation on the basis of IRP-IREs system. This then leading to cellular iron deficiency and HCC cells growth suppression in vitro and in vivo. Interestingly, KLF14 suppressed the transcription of IRP2 via recruiting SIRT1 to reduce the histone acetylation of the IRP2 promoter, resulting in iron depletion and cell growth suppression. More important, we found fluphenazine is an activator of KLF14, inhibiting HCC cells growth through inducing iron deficiency. CONCLUSION KLF14 acts as a tumor suppressor which inhibits the proliferation of HCC cells by modulating cellular iron metabolism via the repression of IRP2. We identified Fluphenazine, as an activator of KLF14, could be a potential compound for HCC therapy. Our findings therefore provide an innovative insight into the pathogenesis of HCC and a promising therapeutic target.
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Affiliation(s)
- Hui Zhou
- College of Life Science, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Junru Chen
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, China
| | - Mingjie Fan
- College of Life Science, Zhejiang University, Hangzhou, 310058, Zhejiang, China.,Department of Pediatrics, The First Affiliated Hospital, School of Medicine Zhejiang University, Hangzhou, 310003, Zhejiang, China
| | - Huajian Cai
- College of Life Science, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Yufei Dong
- College of Life Science, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Yue Qiu
- College of Life Science, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Qianqian Zhuang
- College of Life Science, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Zhaoying Lei
- College of Life Science, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Mengyao Li
- College of Life Science, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Xue Ding
- College of Life Science, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Peng Yan
- College of Life Science, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Aifu Lin
- College of Life Science, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Shusen Zheng
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, China.
| | - Qingfeng Yan
- College of Life Science, Zhejiang University, Hangzhou, 310058, Zhejiang, China. .,Department of Pediatrics, The First Affiliated Hospital, School of Medicine Zhejiang University, Hangzhou, 310003, Zhejiang, China. .,Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Hangzhou, 310058, Zhejiang, China.
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6
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Yoshinaga M, Han K, Morgens DW, Horii T, Kobayashi R, Tsuruyama T, Hia F, Yasukura S, Kajiya A, Cai T, Cruz PHC, Vandenbon A, Suzuki Y, Kawahara Y, Hatada I, Bassik MC, Takeuchi O. The N 6-methyladenosine methyltransferase METTL16 enables erythropoiesis through safeguarding genome integrity. Nat Commun 2022; 13:6435. [PMID: 36307435 PMCID: PMC9616860 DOI: 10.1038/s41467-022-34078-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 10/12/2022] [Indexed: 02/07/2023] Open
Abstract
During erythroid differentiation, the maintenance of genome integrity is key for the success of multiple rounds of cell division. However, molecular mechanisms coordinating the expression of DNA repair machinery in erythroid progenitors are poorly understood. Here, we discover that an RNA N6-methyladenosine (m6A) methyltransferase, METTL16, plays an essential role in proper erythropoiesis by safeguarding genome integrity via the control of DNA-repair-related genes. METTL16-deficient erythroblasts exhibit defective differentiation capacity, DNA damage and activation of the apoptotic program. Mechanistically, METTL16 controls m6A deposition at the structured motifs in DNA-repair-related transcripts including Brca2 and Fancm mRNAs, thereby upregulating their expression. Furthermore, a pairwise CRISPRi screen revealed that the MTR4-nuclear RNA exosome complex is involved in the regulation of METTL16 substrate mRNAs in erythroblasts. Collectively, our study uncovers that METTL16 and the MTR4-nuclear RNA exosome act as essential regulatory machinery to maintain genome integrity and erythropoiesis.
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Affiliation(s)
- Masanori Yoshinaga
- grid.258799.80000 0004 0372 2033Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501 Japan
| | - Kyuho Han
- grid.168010.e0000000419368956Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - David W. Morgens
- grid.168010.e0000000419368956Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Takuro Horii
- grid.256642.10000 0000 9269 4097Laboratory of Genome Science, Biosignal Genome Resource Center, Institute for Molecular and Cellular Regulation, Gunma University, Gunma, 371-8512 Japan
| | - Ryosuke Kobayashi
- grid.256642.10000 0000 9269 4097Laboratory of Genome Science, Biosignal Genome Resource Center, Institute for Molecular and Cellular Regulation, Gunma University, Gunma, 371-8512 Japan
| | - Tatsuaki Tsuruyama
- grid.258799.80000 0004 0372 2033Department of Drug and Discovery Medicine, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501 Japan
| | - Fabian Hia
- grid.258799.80000 0004 0372 2033Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501 Japan
| | - Shota Yasukura
- grid.258799.80000 0004 0372 2033Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501 Japan
| | - Asako Kajiya
- grid.258799.80000 0004 0372 2033Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501 Japan
| | - Ting Cai
- grid.258799.80000 0004 0372 2033Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501 Japan
| | - Pedro H. C. Cruz
- grid.136593.b0000 0004 0373 3971Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Osaka, 565-0871 Japan
| | - Alexis Vandenbon
- grid.258799.80000 0004 0372 2033Laboratory of Tissue Homeostasis, Institute for Life and Medical Sciences, Kyoto University, Kyoto, 606-8507 Japan
| | - Yutaka Suzuki
- grid.26999.3d0000 0001 2151 536XLaboratory of Functional Genomics, Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, 277-8562 Japan
| | - Yukio Kawahara
- grid.136593.b0000 0004 0373 3971Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Osaka, 565-0871 Japan
| | - Izuho Hatada
- grid.256642.10000 0000 9269 4097Laboratory of Genome Science, Biosignal Genome Resource Center, Institute for Molecular and Cellular Regulation, Gunma University, Gunma, 371-8512 Japan ,grid.256642.10000 0000 9269 4097Viral Vector Core, Gunma University Initiative for Advanced Research (GIAR), Gunma, 371-8512 Japan
| | - Michael C. Bassik
- grid.168010.e0000000419368956Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Osamu Takeuchi
- grid.258799.80000 0004 0372 2033Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501 Japan
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7
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Jia F, Li H, Jiao Q, Li C, Fu L, Cui C, Jiang H, Zhang L. Deubiquitylase OTUD3 prevents Parkinson’s disease through stabilizing iron regulatory protein 2. Cell Death Dis 2022; 13:418. [PMID: 35490179 PMCID: PMC9056525 DOI: 10.1038/s41419-022-04704-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 02/13/2022] [Accepted: 03/02/2022] [Indexed: 11/16/2022]
Abstract
Iron deposits are neuropathological hallmark of Parkinson’s disease (PD). Iron regulatory protein 2 (IRP2) is a key factor in regulating brain iron homeostasis. Although two ubiquitin ligases that promote IRP2 degradation have been identified, the deubiquitylase for stabilization of IRP2 in PD remains undefined. Here, we report OTUD3 (OTU domain-containing protein 3) functions as a deubiquitylase for IRP2, interacts with IRP2 in the cytoplasm, de-polyubiquitylates, and stabilizes IRP2 protein in an iron-independent manner. Depletion of OTUD3 results in a disorder of iron metabolism. OTUD3 knockout mice display nigral iron accumulation, motor deficits, and nigrostriatal dopaminergic neurodegeneration, which resembles the pathology of PD. Consistently, decreased levels of OTUD3 are detected in transgenic PD mice expressing A53T mutant of human α-synuclein. Five single nucleotide polymorphism mutations of OTUD3 are present in cases of sporadic PD or controls, although no significant associations of OTUD3 SNPs with sporadic PD are detected. Taken together, these findings demonstrate that OTUD3 is a bona fide deubiquitylase for IRP2 and plays a critical role in the nigral iron deposits in PD.
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8
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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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9
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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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10
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Kopeć Z, Starzyński RR, Jończy A, Mazgaj R, Lipiński P. Role of Iron Metabolism-Related Genes in Prenatal Development: Insights from Mouse Transgenic Models. Genes (Basel) 2021; 12:1382. [PMID: 34573364 PMCID: PMC8465470 DOI: 10.3390/genes12091382] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/30/2021] [Accepted: 09/01/2021] [Indexed: 12/20/2022] Open
Abstract
Iron is an essential nutrient during all stages of mammalian development. Studies carried out over the last 20 years have provided important insights into cellular and systemic iron metabolism in adult organisms and led to the deciphering of many molecular details of its regulation. However, our knowledge of iron handling in prenatal development has remained remarkably under-appreciated, even though it is critical for the health of both the embryo/fetus and its mother, and has a far-reaching impact in postnatal life. Prenatal development requires a continuous, albeit quantitatively matched with the stage of development, supply of iron to support rapid cell division during embryogenesis in order to meet iron needs for erythropoiesis and to build up hepatic iron stores, (which are the major source of this microelement for the neonate). Here, we provide a concise overview of current knowledge of the role of iron metabolism-related genes in the maintenance of iron homeostasis in pre- and post-implantation development based on studies on transgenic (mainly knock-out) mouse models. Most studies on mice with globally deleted genes do not conclude whether underlying in utero iron disorders or lethality is due to defective placental iron transport or iron misregulation in the embryo/fetus proper (or due to both). Therefore, there is a need of animal models with tissue specific targeted deletion of genes to advance the understanding of prenatal iron metabolism.
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Affiliation(s)
| | | | | | | | - Paweł Lipiński
- Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, 05-552 Jastrzębiec, Poland; (Z.K.); (R.R.S.); (A.J.); (R.M.)
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11
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Haschka D, Tymoszuk P, Petzer V, Hilbe R, Heeke S, Dichtl S, Skvortsov S, Demetz E, Berger S, Seifert M, Mitterstiller AM, Moser P, Bumann D, Nairz M, Theurl I, Weiss G. Ferritin H deficiency deteriorates cellular iron handling and worsens Salmonella typhimurium infection by triggering hyperinflammation. JCI Insight 2021; 6:e141760. [PMID: 34236052 PMCID: PMC8410025 DOI: 10.1172/jci.insight.141760] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 05/26/2021] [Indexed: 12/30/2022] Open
Abstract
Iron is an essential nutrient for mammals as well as for pathogens. Inflammation-driven changes in systemic and cellular iron homeostasis are central for host-mediated antimicrobial strategies. Here, we studied the role of the iron storage protein ferritin H (FTH) for the control of infections with the intracellular pathogen Salmonella enterica serovar Typhimurium by macrophages. Mice lacking FTH in the myeloid lineage (LysM-Cre+/+Fthfl/fl mice) displayed impaired iron storage capacities in the tissue leukocyte compartment, increased levels of labile iron in macrophages, and an accelerated macrophage-mediated iron turnover. While under steady-state conditions, LysM-Cre+/+Fth+/+ and LysM-Cre+/+Fthfl/fl animals showed comparable susceptibility to Salmonella infection, i.v. iron supplementation drastically shortened survival of LysM-Cre+/+Fthfl/fl mice. Mechanistically, these animals displayed increased bacterial burden, which contributed to uncontrolled triggering of NF-κB and inflammasome signaling and development of cytokine storm and death. Importantly, pharmacologic inhibition of the inflammasome and IL-1β pathways reduced cytokine levels and mortality and partly restored infection control in iron-treated ferritin-deficient mice. These findings uncover incompletely characterized roles of ferritin and cellular iron turnover in myeloid cells in controlling bacterial spread and for modulating NF-κB and inflammasome-mediated cytokine activation, which may be of vital importance in iron-overloaded individuals suffering from severe infections and sepsis.
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Affiliation(s)
- David Haschka
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - Piotr Tymoszuk
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - Verena Petzer
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - Richard Hilbe
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - Simon Heeke
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - Stefanie Dichtl
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - Sergej Skvortsov
- Department of Therapeutic Radiology and Oncology, Laboratory for Experimental and Translational Research on Radiation Oncology, Tyrolean Cancer Research Institute, Medical University of Innsbruck, Innsbruck, Austria
| | - Egon Demetz
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - Sylvia Berger
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - Markus Seifert
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | | | | | - Dirk Bumann
- Biozentrum, University of Basel, Klingelbergstrasse, Basel, Switzerland
| | - Manfred Nairz
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - Igor Theurl
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - Guenter Weiss
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
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12
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Camaschella C, Pagani A. Mendelian inheritance of anemia due to disturbed iron homeostasis. Semin Hematol 2021; 58:175-181. [PMID: 34389109 DOI: 10.1053/j.seminhematol.2021.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 05/16/2021] [Accepted: 05/31/2021] [Indexed: 02/01/2023]
Abstract
Genetic disorders that affect proteins involved in maintaining iron balance may lead to Mendelian anemias. They may be classified as defects of intestinal iron absorption, iron transport in the circulation, iron uptake and utilization by maturing erythroid cells, iron recycling by macrophages and systemic regulation of iron homeostasis. All these Mendelian anemias are rare disorders, prevalently recessive, characterized by microcytic and hypochromic red blood cells. Advances in our knowledge of iron metabolism and its systemic regulation on one side have facilitated the identification of novel iron related anemias, while on the other the study of the affected patients and of the corresponding animal models have contributed to our understanding of iron trafficking and regulation.
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Affiliation(s)
- Clara Camaschella
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy.
| | - Alessia Pagani
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
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13
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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: 25] [Impact Index Per Article: 8.3] [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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14
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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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15
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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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16
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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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17
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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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18
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Hernández-Gallardo AK, Missirlis F. Cellular iron sensing and regulation: Nuclear IRP1 extends a classic paradigm. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118705. [PMID: 32199885 DOI: 10.1016/j.bbamcr.2020.118705] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/02/2020] [Accepted: 03/16/2020] [Indexed: 01/26/2023]
Abstract
The classic view is that iron regulatory proteins operate at the post-transcriptional level. Iron Regulatory Protein 1 (IRP1) shifts between an apo-form that binds mRNAs and a holo-form that harbors a [4Fe4S] cluster. The latter form is not considered relevant to iron regulation, but rather thought to act as a non-essential cytosolic aconitase. Recent work in Drosophila, however, shows that holo-IRP1 can also translocate to the nucleus, where it appears to downregulate iron metabolism genes, preparing the cell for a decline in iron uptake. The shifting of IRP1 between states requires a functional mitoNEET pathway that includes a glycogen branching enzyme for the repair or disassembly of IRP1's oxidatively damaged [3Fe4S] cluster. The new findings add to the notion that glucose metabolism is modulated by iron metabolism. Furthermore, we propose that ferritin ferroxidase activity participates in the repair of the IRP1 [3Fe4S] cluster leading to the hypothesis that cytosolic ferritin directly contributes to cellular iron sensing.
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Affiliation(s)
| | - Fanis Missirlis
- Departamento de Fisiología, Biofísica y Neurociencias, Cinvestav, CDMX, Mexico.
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19
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van Vuren AJ, van Wijk R, van Beers EJ, Marx JJ. Liver Iron Retention Estimated from Utilization of Oral and Intravenous Radioiron in Various Anemias and Hemochromatosis in Humans. Int J Mol Sci 2020; 21:ijms21031077. [PMID: 32041196 PMCID: PMC7037197 DOI: 10.3390/ijms21031077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 01/28/2020] [Accepted: 02/04/2020] [Indexed: 01/19/2023] Open
Abstract
Patients with hereditary hemochromatosis and non-transfusion-dependent hereditary anemia develop predominantly liver iron-overload. We present a unique method allowing quantification of liver iron retention in humans during first-pass of 59Fe-labeled iron through the portal system, using standard ferrokinetic techniques measuring red cell iron uptake after oral and intravenous 59Fe administration. We present data from patients with iron deficiency (ID; N = 47), hereditary hemochromatosis (HH; N = 121) and non-transfusion-dependent hereditary anemia (HA; N = 40). Mean mucosal iron uptake and mucosal iron transfer (±SD) were elevated in patients with HH (59 ± 18%, 80 ± 15% respectively), HA (65 ± 17%, 74 ± 18%) and ID (84 ± 14%, 94 ± 6%) compared to healthy controls (43 ± 19%, 64 ± 18%) (p < 0.05) resulting in increased iron retention after 14 days compared to healthy controls in all groups (p < 0.01). The fraction of retained iron utilized for red cell production was 0.37 ± 0.17 in untreated HA, 0.55 ± 0.20 in untreated HH and 0.99 ± 0.22 in ID (p < 0.01). Interestingly, compared to red blood cell iron utilization after oral iron administration, red blood cell iron utilization was higher after injection of transferrin-bound iron in HA and HH. Liver iron retention was considerably higher in HH and HA compared to ID. We hypothesize that albumin serves as a scavenger of absorbed Fe(II) for delivering albumin-bound Fe(III) to hepatocytes.
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Affiliation(s)
- Annelies J. van Vuren
- Van Creveldkliniek, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Richard van Wijk
- Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Eduard J. van Beers
- Van Creveldkliniek, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
- Correspondence: ; Tel.: +31-88-755-84-50
| | - Joannes J.M. Marx
- Departments of Haematology and Internal Medicine, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
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20
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Santos MCFD, Anderson CP, Neschen S, Zumbrennen-Bullough KB, Romney SJ, Kahle-Stephan M, Rathkolb B, Gailus-Durner V, Fuchs H, Wolf E, Rozman J, de Angelis MH, Cai WM, Rajan M, Hu J, Dedon PC, Leibold EA. Irp2 regulates insulin production through iron-mediated Cdkal1-catalyzed tRNA modification. Nat Commun 2020; 11:296. [PMID: 31941883 PMCID: PMC6962211 DOI: 10.1038/s41467-019-14004-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 12/06/2019] [Indexed: 12/12/2022] Open
Abstract
Regulation of cellular iron homeostasis is crucial as both iron excess and deficiency cause hematological and neurodegenerative diseases. Here we show that mice lacking iron-regulatory protein 2 (Irp2), a regulator of cellular iron homeostasis, develop diabetes. Irp2 post-transcriptionally regulates the iron-uptake protein transferrin receptor 1 (TfR1) and the iron-storage protein ferritin, and dysregulation of these proteins due to Irp2 loss causes functional iron deficiency in β cells. This impairs Fe-S cluster biosynthesis, reducing the function of Cdkal1, an Fe-S cluster enzyme that catalyzes methylthiolation of t6A37 in tRNALysUUU to ms2t6A37. As a consequence, lysine codons in proinsulin are misread and proinsulin processing is impaired, reducing insulin content and secretion. Iron normalizes ms2t6A37 and proinsulin lysine incorporation, restoring insulin content and secretion in Irp2-/- β cells. These studies reveal a previously unidentified link between insulin processing and cellular iron deficiency that may have relevance to type 2 diabetes in humans.
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Affiliation(s)
- Maria C Ferreira Dos Santos
- Department of Medicine, Division of Hematology, University of Utah, Salt Lake City, UT, 84112, USA.,Molecular Medicine Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Cole P Anderson
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, 84112, USA.,Department of Oncological Sciences, University of Utah, Salt Lake City, UT, 84112, USA.,Landstuhl Regional Medical Center, 66849, Landstuhl, Germany
| | - Susanne Neschen
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Kimberly B Zumbrennen-Bullough
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, 84112, USA.,Department of Oncological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Steven J Romney
- Department of Medicine, Division of Hematology, University of Utah, Salt Lake City, UT, 84112, USA.,Molecular Medicine Program, University of Utah, Salt Lake City, UT, 84112, USA.,Thermo Fisher Scientific, Waltham, MA, 02451, USA
| | - Melanie Kahle-Stephan
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,Medizinische Hochschule Brandenburg Theodor Fontane Institut für Sozialmedizin und Epidemiologie, 14770, Brandenburg an der Havel, Germany
| | - Birgit Rathkolb
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,Institute of Molecular Animal Breeding and Biotechnology, Gene Center, Ludwig-Maximilians-Universität München, Feodor-Lynen Strasse 25, 81377, Munich, Germany
| | - Valerie Gailus-Durner
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Helmut Fuchs
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Eckhard Wolf
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, Ludwig-Maximilians-Universität München, Feodor-Lynen Strasse 25, 81377, Munich, Germany
| | - Jan Rozman
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prumyslova, 595, 252 50 Vestec, Czech Republic
| | - Martin Hrabe de Angelis
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, Alte Akademie 8, 85354, Freising, Germany
| | - Weiling Maggie Cai
- Department of Microbiology, National University of Singapore, Singapore, Singapore, 119077.,Antimicrobial Resistance Interdisciplinary Research Group (IRG), Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, Singapore, Singapore, 138602.,Agilent Technologies, 1 Yishun Ave 7, Singapore, Singapore, 768923
| | - Malini Rajan
- Department of Medicine, Division of Hematology, University of Utah, Salt Lake City, UT, 84112, USA.,Molecular Medicine Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Jennifer Hu
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Celgene Corporation, 1616 Eastlake Ave East, Seattle, WA, 98102, USA
| | - Peter C Dedon
- Antimicrobial Resistance Interdisciplinary Research Group (IRG), Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, Singapore, Singapore, 138602.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Elizabeth A Leibold
- Department of Medicine, Division of Hematology, University of Utah, Salt Lake City, UT, 84112, USA. .,Molecular Medicine Program, University of Utah, Salt Lake City, UT, 84112, USA. .,Department of Oncological Sciences, University of Utah, Salt Lake City, UT, 84112, USA.
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21
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Zhang J, Kong X, Zhang Y, Sun W, Xu E, Chen X. Mdm2 is a target and mediator of IRP2 in cell growth control. FASEB J 2019; 34:2301-2311. [PMID: 31907996 DOI: 10.1096/fj.201902278rr] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 11/20/2019] [Accepted: 11/25/2019] [Indexed: 12/26/2022]
Abstract
Iron is an essential element to all living organisms and plays a vital role in many cellular processes, such as DNA synthesis and energy production. The Mdm2 oncogene is an E3 ligase and known to promote tumor growth. However, the role of Mdm2 in iron homeostasis is not certain. Here, we showed that Mdm2 expression was increased by iron depletion but decreased by iron repletion. We also showed that Iron Regulatory Protein 2 (IRP2) mediated iron-regulated Mdm2 expression. Specifically, Mdm2 expression was increased by ectopic IRP2 but decreased by knockdown or knockout of IRP2 in human cancer cells as well as in mouse embryonic fibroblasts. In addition, we showed that IRP2-regulated Mdm2 expression was independent of tumor suppressor p53. Mechanistically, we found that IRP2 stabilized Mdm2 transcript via binding to an iron response element (IRE) in the 3'UTR of Mdm2 mRNA. Finally, we showed that Mdm2 is required for IRP2-mediated cell proliferation and Mdm2 expression is highly associated with IRP2 in both the normal and cancerous liver tissues. Together, we uncover a novel regulation of Mdm2 by IRP2 via mRNA stability and that the IRP2-Mdm2 axis may play a critical role in cell growth.
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Affiliation(s)
- Jin Zhang
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, Davis, California
| | - Xiangmudong Kong
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, Davis, California
| | - Yanhong Zhang
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, Davis, California
| | - Wenqiang Sun
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, Davis, California
| | - Enshun Xu
- 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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Iron regulatory protein 2 modulates the switch from aerobic glycolysis to oxidative phosphorylation in mouse embryonic fibroblasts. Proc Natl Acad Sci U S A 2019; 116:9871-9876. [PMID: 31040213 DOI: 10.1073/pnas.1820051116] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The importance of the role of iron regulatory proteins (IRPs) in mitochondrial iron homeostasis and function has been raised. To understand how an IRP affects mitochondrial function, we used globally Irp2-depleted mouse embryonic fibroblasts (MEFs) and found that Irp2 ablation significantly induced the expression of both hypoxia-inducible factor subunits, Hif1α and Hif2α. The increase of Hif1α up-regulated its targeted genes, enhancing glycolysis, and the increase of Hif2α down-regulated the expression of iron-sulfur cluster (Fe-S) biogenesis-related and electron transport chain (ETC)-related genes, weakening mitochondrial respiration. Inhibition of Hif1α by genetic knockdown or a specific inhibitor prevented Hif1α-targeted gene expression, leading to decreased aerobic glycolysis. Inhibition of Hif2α by genetic knockdown or selective disruption of the heterodimerization of Hif2α and Hif1β restored the mitochondrial ETC and coupled oxidative phosphorylation (OXPHOS) by enhancing Fe-S biogenesis and increasing ETC-related gene expression. Our results indicate that Irp2 modulates the metabolic switch from aerobic glycolysis to OXPHOS that is mediated by Hif1α and Hif2α in MEFs.
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23
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Characterization of Tfrc-mutant mice with microcytic phenotypes. Blood Adv 2019; 2:1914-1922. [PMID: 30093529 DOI: 10.1182/bloodadvances.2018018820] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 06/15/2018] [Indexed: 01/01/2023] Open
Abstract
To identify novel regulators of erythropoiesis, we performed independent forward genetic screens using the chemical mutagen ENU in mice. Among progeny displaying microcytic red-cell phenotypes, 7 independent mouse strains harboring mutations within the transferrin receptor gene Tfrc were identified. Six of the mutants, including the previously described red blood cell 6 (RBC6) strain, displayed reduced erythroblast CD71 expression and midgestation lethality of homozygotes (E12.5-E14.5), and 1 novel strain, RBC21, displayed a variable phenotype with sustained CD71 expression and late homozygous lethality (E18.5). Standard iron studies were normal in the RBC21 mutant, but intracellular ferritin was significantly reduced. The microcytic phenotype seen in the RBC21 strain was the result of impaired binding of transferrin to the receptor. Neither RBC6 nor RBC21 responded to iron replacement therapy. These studies describe how point mutations of the transferrin receptor can cause a microcytic anemia that does not respond to iron therapy and would not be detected by routine iron studies, such as serum ferritin.
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Rouault TA. The indispensable role of mammalian iron sulfur proteins in function and regulation of multiple diverse metabolic pathways. Biometals 2019; 32:343-353. [PMID: 30923992 PMCID: PMC6584224 DOI: 10.1007/s10534-019-00191-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 03/18/2019] [Indexed: 02/07/2023]
Abstract
In recent years, iron sulfur (Fe–S) proteins have been identified as key players in mammalian metabolism, ranging from long-known roles in the respiratory complexes and the citric acid cycle, to more recently recognized roles in RNA and DNA metabolism. Fe–S cofactors have often been missed because of their intrinsic lability and oxygen sensitivity. More Fe–S proteins have now been identified owing to detection of their direct interactions with components of the Fe–S biogenesis machinery, and through use of informatics to detect a motif that binds the co-chaperone responsible for transferring nascent Fe–S clusters to domains of recipient proteins. Dissection of the molecular steps involved in Fe–S transfer to Fe–S proteins has revealed that direct and shielded transfer occurs through highly conserved pathways that operate in parallel in the mitochondrial matrix and in the cytosolic/nuclear compartments of eukaryotic cells. Because Fe–S clusters have the unusual ability to accept or donate single electrons in chemical reactions, their presence renders complex chemical reactions possible. In addition, Fe–S clusters may function as sensors that interconnect activity of metabolic pathways with cellular redox status. Presence in pathways that control growth and division may enable cells to regulate their growth according to sufficiency of energy stores represented by redox capacity, and oxidation of such proteins could diminish anabolic activities to give cells an opportunity to restore energy supplies. This review will discuss mechanisms of Fe–S biogenesis and delivery, and methods that will likely reveal important roles of Fe–S proteins in proteins not yet recognized as Fe–S proteins.
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25
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Muto Y, Moroishi T, Ichihara K, Nishiyama M, Shimizu H, Eguchi H, Moriya K, Koike K, Mimori K, Mori M, Katayama Y, Nakayama KI. Disruption of FBXL5-mediated cellular iron homeostasis promotes liver carcinogenesis. J Exp Med 2019; 216:950-965. [PMID: 30877170 PMCID: PMC6446870 DOI: 10.1084/jem.20180900] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 01/15/2019] [Accepted: 02/25/2019] [Indexed: 12/17/2022] Open
Abstract
Hepatocellular iron overload elicited by ablation of the iron-sensing ubiquitin ligase FBXL5 promotes liver carcinogenesis induced by exposure to a chemical carcinogen or hepatitis virus, suggesting that FBXL5 is a previously unrecognized oncosuppressor in liver carcinogenesis in mice. Hepatic iron overload is a risk factor for progression of hepatocellular carcinoma (HCC), although the molecular mechanisms underlying this association have remained unclear. We now show that the iron-sensing ubiquitin ligase FBXL5 is a previously unrecognized oncosuppressor in liver carcinogenesis in mice. Hepatocellular iron overload elicited by FBXL5 ablation gave rise to oxidative stress, tissue damage, inflammation, and compensatory proliferation of hepatocytes and to consequent promotion of liver carcinogenesis induced by exposure to a chemical carcinogen. The tumor-promoting outcome of FBXL5 deficiency in the liver was also found to be effective in a model of virus-induced HCC. FBXL5-deficient mice thus constitute the first genetically engineered mouse model of liver carcinogenesis promoted by iron overload. In addition, dysregulation of FBXL5-mediated cellular iron homeostasis was found to be associated with poor prognosis in human HCC, suggesting that FBXL5 plays a key role in defense against hepatocarcinogenesis.
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Affiliation(s)
- Yoshiharu Muto
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Toshiro Moroishi
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Kazuya Ichihara
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Masaaki Nishiyama
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Hideyuki Shimizu
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Hidetoshi Eguchi
- Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Kyoji Moriya
- Department of Infection Control and Prevention, The University of Tokyo Hospital, Tokyo, Japan
| | - Kazuhiko Koike
- Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Koshi Mimori
- Department of Surgery, Kyushu University, Beppu Hospital, Beppu, Japan
| | - Masaki Mori
- Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yuta Katayama
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Keiichi I Nakayama
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
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26
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Iwai K. Regulation of cellular iron metabolism: Iron-dependent degradation of IRP by SCF FBXL5 ubiquitin ligase. Free Radic Biol Med 2019; 133:64-68. [PMID: 30218771 DOI: 10.1016/j.freeradbiomed.2018.09.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 09/10/2018] [Accepted: 09/12/2018] [Indexed: 12/30/2022]
Abstract
Because of essentiality and toxicity of iron in our body, iron metabolism is tightly regulated in cells. In mammalian cells, iron regulatory protein 1 and 2 (IRP1 and IRP2) are the central regulators of cellular iron metabolism. IRPs regulate iron metabolism by interacting with the RNA stem-loop structures, iron-responsive elements (IREs), found on the transcripts encoding proteins involved in iron metabolism only in iron depleted condition. It is also well-known that the ubiquitin system plays central roles in cellular iron regulation because both IRPs having the IRE binding activity are recognized and ubiquitinated by the SCFFBXL5 ubiquitin ligase in condition of iron-replete. FBXL5, which is a substrate recognition subunit of SCFFBXL5, senses iron availability via its hemerythrin-like domain. In this small article, current understanding of the roles of SCFFBXL5-mediated degradation of IRPs played in cellular iron metabolism is discussed.
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Affiliation(s)
- Kazuhiro Iwai
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Kyoto University, Yoshida-konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
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27
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Iron regulatory protein 2 deficiency may correlate with insulin resistance. Biochem Biophys Res Commun 2019; 510:191-197. [PMID: 30685084 DOI: 10.1016/j.bbrc.2019.01.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 01/05/2019] [Indexed: 12/12/2022]
Abstract
Iron is known to be a crucial regulator of glucose, and several studies have demonstrated that iron overload is one of the risk factors for insulin resistance and diabetes; however, the mechanism has not yet been clarified. To investigate the effect of iron overload on glucose metabolism and the underlying mechanism, Irp2 knockout (Irp2-/-) mice (endogenous iron overload model) were used. We found that Irp2-/- mice exhibited hyperglycemia and iron overload in the liver and skeletal muscle. Increased MDA, decreased SOD levels, and increased cell apoptosis were also found in the liver and muscle of Irp2-/- mice. Glucose concentrations were significantly higher in Irp2-/- mice in insulin tolerance tests. However, early-phase insulin secretion was not altered in Irp2-/- mice. The expression of hepatic IRS2 and muscle GLUT4 was declined in Irp2-/- mice at both mRNA and protein levels when compared with those of wild-type control. In conclusions, Irp2-/- mice showed hyperglycemia, which might due to insulin resistance rather than due to impaired insulin secretion.
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28
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Zhou Y, Yang Y, Liu Y, Chang H, Liu K, Zhang X, Chang Y. Irp2 Knockout Causes Osteoporosis by Inhibition of Bone Remodeling. Calcif Tissue Int 2019; 104:70-78. [PMID: 30191282 DOI: 10.1007/s00223-018-0469-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 08/22/2018] [Indexed: 02/07/2023]
Abstract
It has been found that iron disorder may lead to osteoporosis. However, the mechanism has been little explored. In the present study, we try to investigate the effects of iron disorder on bone metabolism using Irp2 knockout (Irp2-/-) mice. Female Irp2-/- mice were used in this study. Bone mineral density (BMD) was measured by Micro-CT. Serum markers for bone turnover were measured by enzyme-linked immunosorbent assay. Content of iron was measured in bone and liver tissue, and Vitamin D 25-hydroxylase (CYP2R1) content was measured in liver tissue. Relative gene expression involved in iron export and uptake, and some genes involved in activities of osteoblast and osteoclast were all measured by real-time PCR and western blot. Compared to wild-type mice, Irp2-/- mice exhibited reduced BMD, bone iron deficiency, and hepatic iron overload. Serum levels of 25(OH)D3 and markers for bone formation such as bone alkaline phosphatase (Balp), bone-gla-protein (BGP), and type I collagen alpha1 chain (Col I α1) were decreased, while markers for bone resorption including cathepsin K (Ctsk) and tartrate-resistant acid phosphatase (Trap) were all significantly increased. Hepatic CYP2R1 level was decreased in Irp2-/- mice compared with wild-type control mice. Compared to wild-type C57BL6 control mice, the expression of genes involved in osteoblast activity such as Balp, BGP, and Col I α1 were all significantly decreased in bone tissue, while genes for osteoclast activity such as Ctsk and Trap were all markedly increased in Irp2-/- mice at mRNA level. Genes involved in iron storage, uptake, and exporting were also measured in bone tissue. Posttranscriptionally decreased ferritin (FTL), ferroportin 1 (FPN1), and increased transferrin receptor 1 (TfR1) gene expressions have been unexpectedly found in bone tissue of Irp2-/- mice. Irp2-/- mice exhibit reduced bone iron content and osteoporosis. Decreased circulating 25(OH)D3 levels promoted activity of osteoclast, while impaired activity of osteoblast may contribute to pathogenesis of osteoporosis. And, reduced bone iron content may not be totally caused by TfR1-dependent pathways.
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Affiliation(s)
- Yaru Zhou
- Department of Endocrinology, Third Hospital of Hebei Medical University, Shijiazhuang, China.
| | - Yu Yang
- Department of Endocrinology, Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Yan Liu
- Department of Endocrinology, Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Hengrui Chang
- Department of Orthopaedic Surgery, Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Kuanzhi Liu
- Department of Endocrinology, Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Xiaojuan Zhang
- Department of Endocrinology, Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Yanzhong Chang
- College of Life Science, Hebei Normal University, Shijiazhuang, 050051, China.
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29
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Sukhbaatar N, Weichhart T. Iron Regulation: Macrophages in Control. Pharmaceuticals (Basel) 2018; 11:ph11040137. [PMID: 30558109 PMCID: PMC6316009 DOI: 10.3390/ph11040137] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 12/10/2018] [Accepted: 12/12/2018] [Indexed: 12/21/2022] Open
Abstract
Macrophages are sentinel cells of the innate immune system and have important functions in development, tissue homeostasis, and immunity. These phylogenetically ancient cells also developed a variety of mechanisms to control erythropoiesis and the handling of iron. Red pulp macrophages in the spleen, Kupffer cells in the liver, and central nurse macrophages in the bone marrow ensure a coordinated metabolism of iron to support erythropoiesis. Phagocytosis of senescent red blood cells by macrophages in the spleen and the liver provide a continuous delivery of recycled iron under steady-state conditions and during anemic stress. Central nurse macrophages in the bone marrow utilize this iron and provide a cellular scaffold and niche to promote differentiation of erythroblasts. This review focuses on the role of the distinct macrophage populations that contribute to efficient iron metabolism and highlight important cellular and systemic mechanisms involved in iron-regulating processes.
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Affiliation(s)
- Nyamdelger Sukhbaatar
- Medical University of Vienna, Center for Pathobiochemistry and Genetics, Vienna 1090, Austria.
| | - Thomas Weichhart
- Medical University of Vienna, Center for Pathobiochemistry and Genetics, Vienna 1090, Austria.
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30
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Wang L, Liu X, You LH, Ci YZ, Chang S, Yu P, Gao G, Chang YZ. Hepcidin and iron regulatory proteins coordinately regulate ferroportin 1 expression in the brain of mice. J Cell Physiol 2018; 234:7600-7607. [PMID: 30370612 DOI: 10.1002/jcp.27522] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 09/10/2018] [Indexed: 12/31/2022]
Abstract
Iron plays an essential role in various cellular metabolic processes of the body. Maintenance of cellular iron homeostasis is particularly important for keeping the normal functions of the cells. Ferroportin 1 (FPN1) is the currently only known iron exporter on the cell membrane. It has been indicated that the regulation of FPN1 in response to the alteration of iron level mainly involves two processes, posttranscriptional repression by iron regulatory proteins (IRPs) and posttranslational degradation by hepcidin, the major iron-sensing hormone. However, whether there is any communication between the two types of regulations or which one plays dominant role has not been reported. In our study with IRP2-/- mice, we found that knockout of IRP2 increased FPN1 expression in the cerebral cortex of IRP2-/- mice, whereas the upregulation of FPN1 was more significant in IRP1/IRP2 dual knockdown fibroblasts. Interestingly, we found that the knockout of IRP2 severely affected the regulation effect of hepcidin on FPN1 in mouse brain. FPN1 level decreased dramatically in the brain of wild-type mice injected with hepcidin, but it did not decrease much in IRP2 knockout mice. Further investigation disclosed that the compromised hepcidin-FPN1 regulation in IRP2-/- cells was directly dependent on the existence of iron-responsive element (IRE) in FPN1 messenger RNA. These results indicate that IRPs and hepcidin coordinately regulate the FPN1 level in mice. This study will provide a more comprehensive understanding of the regulatory mechanisms of FPN1 expression.
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Affiliation(s)
- Lan Wang
- Laboratory of Molecular Iron Metabolism, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei, China
| | - Xiaopeng Liu
- Laboratory of Molecular Iron Metabolism, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei, China
| | - Lin-Hao You
- Laboratory of Molecular Iron Metabolism, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei, China
| | - Yun-Zhe Ci
- Laboratory of Molecular Iron Metabolism, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei, China
| | - Shiyang Chang
- Laboratory of Molecular Iron Metabolism, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei, China
| | - Peng Yu
- Laboratory of Molecular Iron Metabolism, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei, China
| | - Guofen Gao
- Laboratory of Molecular Iron Metabolism, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei, China
| | - Yan-Zhong Chang
- Laboratory of Molecular Iron Metabolism, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei, China
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31
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Weiss A, Spektor L, A. Cohen L, Lifshitz L, Magid Gold I, Zhang DL, Truman-Rosentsvit M, Leichtmann-Bardoogo Y, Nyska A, Addadi S, Rouault TA, Meyron-Holtz EG. Orchestrated regulation of iron trafficking proteins in the kidney during iron overload facilitates systemic iron retention. PLoS One 2018; 13:e0204471. [PMID: 30321179 PMCID: PMC6188744 DOI: 10.1371/journal.pone.0204471] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 09/07/2018] [Indexed: 01/24/2023] Open
Abstract
The exact route of iron through the kidney and its regulation during iron overload are not completely elucidated. Under physiologic conditions, non-transferrin and transferrin bound iron passes the glomerular filter and is reabsorbed through kidney epithelial cells, so that hardly any iron is found in the urine. To study the route of iron reabsorption through the kidney, we analyzed the location and regulation of iron metabolism related proteins in kidneys of mice with iron overload, elicited by iron dextran injections. Transferrin Receptor 1 was decreased as expected, following iron overload. In contrast, the multi-ligand hetero-dimeric receptor-complex megalin/cubilin, which also mediates the internalization of transferrin, was highly up-regulated. Moreover, with increasing iron, intracellular ferritin distribution shifted in renal epithelium from an apical location to a punctate distribution throughout the epithelial cells. In addition, in contrast to many other tissues, the iron exporter ferroportin was not reduced by iron overload in the kidney. Iron accumulated mainly in interstitial macrophages, and more prominently in the medulla than in the cortex. This suggests that despite the reduction of Transferrin Receptor 1, alternative pathways may effectively mediate re-absorption of iron that cycles through the kidney during parenterally induced iron-overload. The most iron consuming process of the body, erythropoiesis, is regulated by the renal erythropoietin producing cells in kidney interstitium. We propose, that the efficient re-absorption of iron by the kidney, also during iron overload enables these cells to sense systemic iron and regulate its usage based on the systemic iron state.
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Affiliation(s)
- Avital Weiss
- Laboratory for Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Lior Spektor
- Laboratory for Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Lyora A. Cohen
- Laboratory for Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Lena Lifshitz
- Laboratory for Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Inbar Magid Gold
- Laboratory for Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - De-Liang Zhang
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Marianna Truman-Rosentsvit
- Laboratory for Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Yael Leichtmann-Bardoogo
- Laboratory for Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Abraham Nyska
- Sackler School of Medicine, Tel Aviv University, and Consultant in Toxicologic Pathology, Timrat, Israel
| | | | - Tracey A. Rouault
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Esther G. Meyron-Holtz
- Laboratory for Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
- * E-mail:
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Cui R, Choi SE, Kim TH, Lee HJ, Lee SJ, Kang Y, Jeon JY, Kim HJ, Lee KW. Iron overload by transferrin receptor protein 1 regulation plays an important role in palmitate-induced insulin resistance in human skeletal muscle cells. FASEB J 2018; 33:1771-1786. [PMID: 30207798 DOI: 10.1096/fj.201800448r] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Free fatty acid is considered to be one of the major pathogenic factors of inducing insulin resistance. The association between iron disturbances and insulin resistance has recently begun to receive a lot of attention. Although skeletal muscles are a major tissue for iron utilization and storage, the role of iron in palmitate (PA)-induced insulin resistance is unknown. We investigated the molecular mechanism underlying iron dysregulation in PA-induced insulin resistance. Interestingly, we found that PA simultaneously increased intracellular iron and induced insulin resistance. The iron chelator deferoxamine dramatically inhibited PA-induced insulin resistance, and iron donors impaired insulin sensitivity by activating JNK. PA up-regulated transferrin receptor 1 (tfR1), an iron uptake protein, which was modulated by iron-responsive element-binding proteins 2. Knockdown of tfR1 and iron-responsive element-binding proteins 2 prevented PA-induced iron uptake and insulin resistance. PA also translocated the tfR1 by stimulating calcium influx, but the calcium chelator, BAPTA-AM, dramatically reduced iron overload by inhibiting tfR1 translocation and ultimately increased insulin sensitivity. Iron overload may play a critical role in PA-induced insulin resistance. Blocking iron overload may thus be a useful strategy for preventing insulin resistance and diabetes.-Cui, R., Choi, S.-E., Kim, T. H., Lee, H. J., Lee, S. J., Kang, Y., Jeon, J. Y., Kim, H. J., Lee, K.-W. Iron overload by transferrin receptor protein 1 regulation plays an important role in palmitate-induced insulin resistance in human skeletal muscle cells.
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Affiliation(s)
- Rihua Cui
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, South Korea
| | - Sung-E Choi
- Department of Physiology, Ajou University School of Medicine, Suwon, South Korea
| | - Tae Ho Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul Medical Center, Seoul, South Korea
| | - Hwa Joung Lee
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, South Korea
| | - Soo Jin Lee
- Department of Physiology, Ajou University School of Medicine, Suwon, South Korea
| | - Yup Kang
- Department of Physiology, Ajou University School of Medicine, Suwon, South Korea
| | - Ja Young Jeon
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, South Korea
| | - Hae Jin Kim
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, South Korea
| | - Kwan-Woo Lee
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, South Korea
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33
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Zhang J, Chen X. p53 tumor suppressor and iron homeostasis. FEBS J 2018; 286:620-629. [PMID: 30133149 DOI: 10.1111/febs.14638] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 07/16/2018] [Accepted: 08/20/2018] [Indexed: 12/20/2022]
Abstract
Iron is an essential nutrient for all living organisms and plays a vital role in many fundamental biochemical processes, such as oxygen transport, energy metabolism, and DNA synthesis. Due to its capability to produce free radicals, iron has deleterious effects and thus, its level needs to be tightly controlled in the body. Deregulation of iron metabolism is known to cause diseases, including anemia by iron deficiency and hereditary hemochromatosis by iron overload. Interestingly, dysregulated iron metabolism occurs frequently in tumor cells and contributes to tumorigenesis. In this review, we will discuss the role of p53 tumor suppressor in iron homeostasis.
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Affiliation(s)
- Jin Zhang
- Comparative Oncology Laboratory, School of Veterinary Medicine and Medicine, University of California at Davis, CA, USA
| | - Xinbin Chen
- Comparative Oncology Laboratory, School of Veterinary Medicine and Medicine, University of California at Davis, CA, USA
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34
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Li H, Zhao H, Hao S, Shang L, Wu J, Song C, Meyron-Holtz EG, Qiao T, Li K. Iron regulatory protein deficiency compromises mitochondrial function in murine embryonic fibroblasts. Sci Rep 2018; 8:5118. [PMID: 29572489 PMCID: PMC5865113 DOI: 10.1038/s41598-018-23175-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 03/07/2018] [Indexed: 01/25/2023] Open
Abstract
Iron is essential for growth and proliferation of mammalian cells. The maintenance of cellular iron homeostasis is regulated by iron regulatory proteins (IRPs) through binding to the cognate iron-responsive elements in target mRNAs and thereby regulating the expression of target genes. Irp1 or Irp2-null mutation is known to reduce the cellular iron level by decreasing transferrin receptor 1 and increasing ferritin. Here, we report that Irp1 or Irp2-null mutation also causes downregulation of frataxin and IscU, two of the core components in the iron-sulfur cluster biogenesis machinery. Interestingly, while the activities of some of iron-sulfur cluster-containing enzymes including mitochondrial aconitase and cytosolic xanthine oxidase were not affected by the mutations, the activities of respiratory chain complexes were drastically diminished resulting in mitochondrial dysfunction. Overexpression of human ISCU and frataxin in Irp1 or Irp2-null cells was able to rescue the defects in iron-sulfur cluster biogenesis and mitochondrial quality. Our results strongly suggest that iron regulatory proteins regulate the part of iron sulfur cluster biogenesis tailored specifically for mitochondrial electron transport chain complexes.
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Affiliation(s)
- Huihui Li
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, P. R. China
| | - Hongting Zhao
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, P. R. China
| | - Shuangying Hao
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, P. R. China
- Medical School of Henan Polytechnic University, Jiaozuo, 454000, P. R. China
| | - Longcheng Shang
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, P. R. China
| | - Jing Wu
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, P. R. China
| | - Chuanhui Song
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, P. R. China
| | - Esther G Meyron-Holtz
- Laboratory for Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Technion, Technion City, Haifa, 32000, Israel
| | - Tong Qiao
- Department of Vascular Surgery, Drum Tower Clinical Medical College of Nanjing Medical University, Nanjing, 210008, P. R. China
| | - Kuanyu Li
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, P. R. China.
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35
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Oikonomidou PR, Rivella S. What can we learn from ineffective erythropoiesis in thalassemia? Blood Rev 2018; 32:130-143. [PMID: 29054350 PMCID: PMC5882559 DOI: 10.1016/j.blre.2017.10.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 09/30/2017] [Accepted: 10/02/2017] [Indexed: 02/07/2023]
Abstract
Erythropoiesis is a dynamic process regulated at multiple levels to balance proliferation, differentiation and survival of erythroid progenitors. Ineffective erythropoiesis is a key feature of various diseases, including β-thalassemia. The pathogenic mechanisms leading to ineffective erythropoiesis are complex and still not fully understood. Altered survival and decreased differentiation of erythroid progenitors are both critical processes contributing to reduced production of mature red blood cells. Recent studies have identified novel important players and provided major advances in the development of targeted therapeutic approaches. In this review, β-thalassemia is used as a paradigmatic example to describe our current knowledge on the mechanisms leading to ineffective erythropoiesis and novel treatments that may have the potential to improve the clinical phenotype of associated diseases in the future.
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Affiliation(s)
- Paraskevi Rea Oikonomidou
- Department of Pediatrics, Division of Hematology, Children's Hospital of Philadelphia (CHOP), Philadelphia, PA, USA.
| | - Stefano Rivella
- Department of Pediatrics, Division of Hematology, Children's Hospital of Philadelphia (CHOP), Philadelphia, PA, USA; Cell and Molecular Biology Graduate Group (CAMB), University of Pennsylvania, Philadelphia, PA, USA.
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36
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Rouault TA, Maio N. Biogenesis and functions of mammalian iron-sulfur proteins in the regulation of iron homeostasis and pivotal metabolic pathways. J Biol Chem 2017; 292:12744-12753. [PMID: 28615439 PMCID: PMC5546015 DOI: 10.1074/jbc.r117.789537] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fe-S cofactors are composed of iron and inorganic sulfur in various stoichiometries. A complex assembly pathway conducts their initial synthesis and subsequent binding to recipient proteins. In this minireview, we discuss how discovery of the role of the mammalian cytosolic aconitase, known as iron regulatory protein 1 (IRP1), led to the characterization of the function of its Fe-S cluster in sensing and regulating cellular iron homeostasis. Moreover, we present an overview of recent studies that have provided insights into the mechanism of Fe-S cluster transfer to recipient Fe-S proteins.
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Affiliation(s)
- Tracey A Rouault
- Molecular Medicine Branch, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892.
| | - Nunziata Maio
- Molecular Medicine Branch, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892
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37
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Zhang Y, Qian Y, Zhang J, Yan W, Jung YS, Chen M, Huang E, Lloyd K, Duan Y, Wang J, Liu G, Chen X. Ferredoxin reductase is critical for p53-dependent tumor suppression via iron regulatory protein 2. Genes Dev 2017; 31:1243-1256. [PMID: 28747430 PMCID: PMC5558926 DOI: 10.1101/gad.299388.117] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/26/2017] [Indexed: 01/20/2023]
Abstract
In this study, Chen and colleagues investigated the biological function of ferredoxin reductase (FDXR), a target of p53. They generated a Fdxr-deficient mouse model and found that the signal from FDXR to iron homeostasis and the p53 pathway was transduced by ferredoxin 2, a substrate of FDXR, and that p53 played a role in iron homeostasis and was required for FDXR-mediated iron metabolism, suggesting that the FDXR–p53 loop is critical for tumor suppression via iron homeostasis. Ferredoxin reductase (FDXR), a target of p53, modulates p53-dependent apoptosis and is necessary for steroidogenesis and biogenesis of iron–sulfur clusters. To determine the biological function of FDXR, we generated a Fdxr-deficient mouse model and found that loss of Fdxr led to embryonic lethality potentially due to iron overload in developing embryos. Interestingly, mice heterozygous in Fdxr had a short life span and were prone to spontaneous tumors and liver abnormalities, including steatosis, hepatitis, and hepatocellular carcinoma. We also found that FDXR was necessary for mitochondrial iron homeostasis and proper expression of several master regulators of iron metabolism, including iron regulatory protein 2 (IRP2). Surprisingly, we found that p53 mRNA translation was suppressed by FDXR deficiency via IRP2. Moreover, we found that the signal from FDXR to iron homeostasis and the p53 pathway was transduced by ferredoxin 2, a substrate of FDXR. Finally, we found that p53 played a role in iron homeostasis and was required for FDXR-mediated iron metabolism. Together, we conclude that FDXR and p53 are mutually regulated and that the FDXR–p53 loop is critical for tumor suppression via iron homeostasis.
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Affiliation(s)
- Yanhong Zhang
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, Davis, California 95616, USA
| | - Yingjuan Qian
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, Davis, California 95616, USA.,College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210014, China
| | - Jin Zhang
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, Davis, California 95616, USA
| | - Wensheng Yan
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, Davis, California 95616, USA
| | - Yong-Sam Jung
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, Davis, California 95616, USA.,College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210014, China
| | - Mingyi Chen
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Eric Huang
- Department of Pathology, School of Medicine, University of California at Davis Health, Sacramento, California 95817, USA
| | - Kent Lloyd
- Department of Surgery, School of Medicine, University of California at Davis Health, Sacramento, California 95817, USA
| | - Yuyou Duan
- Department of Dermatology and Internal Medicine, University of California at Davis Health, Sacramento, California 95616, USA
| | - Jian Wang
- Department of Pathology, School of Medicine, Wayne State University, Detroit, Michigan 48201 USA
| | - Gang Liu
- Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Xinbin Chen
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, Davis, California 95616, USA
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38
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Essential role of FBXL5-mediated cellular iron homeostasis in maintenance of hematopoietic stem cells. Nat Commun 2017; 8:16114. [PMID: 28714470 PMCID: PMC5520054 DOI: 10.1038/ncomms16114] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 05/25/2017] [Indexed: 12/17/2022] Open
Abstract
Hematopoietic stem cells (HSCs) are maintained in a hypoxic niche to limit oxidative stress. Although iron elicits oxidative stress, the importance of iron homeostasis in HSCs has been unknown. Here we show that iron regulation by the F-box protein FBXL5 is required for HSC self-renewal. Conditional deletion of Fbxl5 in mouse HSCs results in cellular iron overload and a reduced cell number. Bone marrow transplantation reveals that FBXL5-deficient HSCs are unable to reconstitute the hematopoietic system of irradiated recipients as a result of stem cell exhaustion. Transcriptomic analysis shows abnormal activation of oxidative stress responses and the cell cycle in FBXL5-deficient mouse HSCs as well as downregulation of FBXL5 expression in HSCs of patients with myelodysplastic syndrome. Suppression of iron regulatory protein 2 (IRP2) accumulation in FBXL5-deficient mouse HSCs restores stem cell function, implicating IRP2 as a potential therapeutic target for human hematopoietic diseases associated with FBXL5 downregulation.
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Metzendorf C, Zeigerer A, Seifert S, Sparla R, Najafi B, Canonne-Hergaux F, Zerial M, Muckenthaler MU. Acute loss of the hepatic endo-lysosomal system in vivo causes compensatory changes in iron homeostasis. Sci Rep 2017. [PMID: 28642463 PMCID: PMC5481338 DOI: 10.1038/s41598-017-02898-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Liver cells communicate with the extracellular environment to take up nutrients via endocytosis. Iron uptake is essential for metabolic activities and cell homeostasis. Here, we investigated the role of the endocytic system for maintaining iron homeostasis. We specifically depleted the small GTPase Rab5 in the mouse liver, causing a transient loss of the entire endo-lysosomal system. Strikingly, endosome depletion led to a fast reduction of hepatic iron levels, which was preceded by an increased abundance of the iron exporter ferroportin. Compensatory changes in livers of Rab5-depleted mice include increased expression of transferrin receptor 1 as well as reduced expression of the iron-regulatory hormone hepcidin. Serum iron indices (serum iron, free iron binding capacity and total iron binding capacity) in Rab5-KD mice were increased, consistent with an elevated splenic and hepatic iron export. Our data emphasize the critical importance of the endosomal compartments in hepatocytes to maintain hepatic and systemic iron homeostasis in vivo. The short time period (between day four and five) upon which these changes occur underscore the fast dynamics of the liver iron pool.
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Affiliation(s)
- Christoph Metzendorf
- Department of Pediatric Hematology, Oncology and Immunology University of Heidelberg, Heidelberg University Clinic, INF 350, 69120, Heidelberg, Germany.,Molecular Medicine Partnership Unit, 69120, Heidelberg, Germany.,Heidelberg University Biochemistry Center (BZH), INF 327, 69120, Heidelberg, Germany
| | - Anja Zeigerer
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany.,Institute for Diabetes and Cancer, Helmholtz Center for Environmental Health, 85764, Neuherberg, Germany
| | - Sarah Seifert
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany
| | - Richard Sparla
- Department of Pediatric Hematology, Oncology and Immunology University of Heidelberg, Heidelberg University Clinic, INF 350, 69120, Heidelberg, Germany.,Molecular Medicine Partnership Unit, 69120, Heidelberg, Germany
| | - Bahar Najafi
- German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany.,Institute for Diabetes and Cancer, Helmholtz Center for Environmental Health, 85764, Neuherberg, Germany
| | | | - Marino Zerial
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany
| | - Martina U Muckenthaler
- Department of Pediatric Hematology, Oncology and Immunology University of Heidelberg, Heidelberg University Clinic, INF 350, 69120, Heidelberg, Germany. .,Molecular Medicine Partnership Unit, 69120, Heidelberg, Germany.
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40
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Milczarek A, Starzyński RR, Styś A, Jończy A, Staroń R, Grzelak A, Lipiński P. A drastic superoxide-dependent oxidative stress is prerequisite for the down-regulation of IRP1: Insights from studies on SOD1-deficient mice and macrophages treated with paraquat. PLoS One 2017; 12:e0176800. [PMID: 28542246 PMCID: PMC5438123 DOI: 10.1371/journal.pone.0176800] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 04/17/2017] [Indexed: 12/21/2022] Open
Abstract
Iron regulatory protein 1 (IRP1) is a cytosolic bifunctional [4Fe-4S] protein which exhibits aconitase activity or binds iron responsive elements (IREs) in untranslated regions of specific mRNA encoding proteins involved in cellular iron metabolism. Superoxide radical (O2.-) converts IRP1 from a [4Fe-4S] aconitase to a [3Fe-4S] „null” form possessing neither aconitase nor trans-regulatory activity. Genetic ablation of superoxide dismutase 1 (SOD1), an antioxidant enzyme that acts to reduce O2.- concentration, revealed a new O2.--dependent regulation of IRP1 leading to the reduction of IRP1 protein level and in consequence to the diminution of IRP1 enzymatic and IRE-binding activities. Here, we attempted to establish whether developmental changes in SOD1 activity occurring in the mouse liver, impact IRP1 expression. We show no correlation between hepatic SOD1 activity and IRP1 protein level neither in pre- nor postnatal period probably because the magnitude of developmental fluctuations in SOD1 activity is relatively small. The comparison of SOD1 activity in regards to IRP1 protein level in the liver of threeSOD1 genotypes (Sod1+/+, Sod1+/- and Sod1-/-) demonstrates that only drastic SOD1 deficiency leads to the reduction of IRP1 protein level. Importantly, we found that in the liver of fetuses lacking SOD1, IRP1 is not down-regulated. To investigate O2.--dependent regulation of IRP1 in a cellular model, we exposed murine RAW 264.7 and bone marrow-derived macrophages to paraquat, widely used as a redox cycler to stimulate O2.-production in cells. We showed that IRP1 protein level as well as aconitase and IRE-binding activities are strongly reduced in macrophages treated with paraquat. The analysis of the expression of IRP1-target genes revealed the increase in L-ferritin protein level resulting from the enhanced transcriptional regulation of the LFt gene and diminished translational repression of L-ferritin mRNA by IRP1. We propose that O2.--dependent up-regulation of this cellular protectant in paraquat-treated macrophages may counterbalance iron-related toxic effects of O2.-.
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Affiliation(s)
- Anna Milczarek
- Department of Molecular Biology, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzębiec, Poland
| | - Rafał R. Starzyński
- Department of Molecular Biology, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzębiec, Poland
| | - Agnieszka Styś
- Department of Molecular Biology, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzębiec, Poland
| | - Aneta Jończy
- Department of Molecular Biology, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzębiec, Poland
| | - Robert Staroń
- Department of Molecular Biology, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzębiec, Poland
| | - Agnieszka Grzelak
- Department of Molecular Biophysics, University of Łódź, Łódź, Poland
| | - Paweł Lipiński
- Department of Molecular Biology, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzębiec, Poland
- * E-mail:
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41
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Papanikolaou G, Pantopoulos K. Systemic iron homeostasis and erythropoiesis. IUBMB Life 2017; 69:399-413. [DOI: 10.1002/iub.1629] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 03/16/2017] [Indexed: 01/01/2023]
Affiliation(s)
- George Papanikolaou
- Department of Nutrition and DieteticsSchool of Health Science and Education, Harokopion UniversityAthens Greece
| | - Kostas Pantopoulos
- Lady Davis Institute for Medical Research and Department of MedicineMcGill UniversityMontreal Quebec Canada
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42
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Wofford JD, Chakrabarti M, Lindahl PA. Mössbauer Spectra of Mouse Hearts Reveal Age-dependent Changes in Mitochondrial and Ferritin Iron Levels. J Biol Chem 2017; 292:5546-5554. [PMID: 28202542 DOI: 10.1074/jbc.m117.777201] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 02/14/2017] [Indexed: 01/12/2023] Open
Abstract
Cardiac function requires continuous high levels of energy, and so iron, a critical player in mitochondrial respiration, is an important component of the heart. Hearts from 57Fe-enriched mice were evaluated by Mössbauer spectroscopy. Spectra consisted of a sextet and two quadrupole doublets. One doublet was due to residual blood, whereas the other was due to [Fe4S4]2+ clusters and low-spin FeII hemes, most of which were associated with mitochondrial respiration. The sextet was due to ferritin; there was no evidence of hemosiderin, a ferritin decomposition product. Iron from ferritin was nearly absent in young hearts, but increased steadily with age. EPR spectra exhibited signals similar to those of brain, liver, and human cells. No age-dependent EPR trends were apparent. Hearts from HFE-/- mice with hemochromatosis contained slightly more iron overall than controls, including more ferritin and less mitochondrial iron; these differences typify slightly older hearts, perhaps reflecting the burden due to this disease. HFE-/- livers were overloaded with ferritin but had low mitochondrial iron levels. IRP2-/- hearts contained less ferritin than controls but normal levels of mitochondrial iron. Hearts of young mice born to an iron-deficient mother contained normal levels of mitochondrial iron and no ferritin; the heart from the mother contained low ferritin and normal levels of mitochondrial iron. High-spin FeII ions were nearly undetectable in heart samples; these were evident in brains, livers, and human cells. Previous Mössbauer spectra of unenriched diseased human hearts lacked mitochondrial and blood doublets and included hemosiderin features. This suggests degradation of iron-containing species during sample preparation.
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Affiliation(s)
| | | | - Paul A Lindahl
- From the Departments of Chemistry and .,Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843
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43
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Grievink H, Zeltcer G, Drenger B, Berenshtein E, Chevion M. Protection by Nitric Oxide Donors of Isolated Rat Hearts Is Associated with Activation of Redox Metabolism and Ferritin Accumulation. PLoS One 2016; 11:e0159951. [PMID: 27447933 PMCID: PMC4957751 DOI: 10.1371/journal.pone.0159951] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 07/11/2016] [Indexed: 11/19/2022] Open
Abstract
Preconditioning (PC) procedures (ischemic or pharmacological) are powerful procedures used for attaining protection against prolonged ischemia and reperfusion (I/R) injury, in a variety of organs, including the heart. The detailed molecular mechanisms underlying the protection by PC are however, complex and only partially understood. Recently, an ‘iron-based mechanism’ (IBM), that includes de novo ferritin synthesis and accumulation, was proposed to explain the specific steps in cardioprotection generated by IPC. The current study investigated whether nitric oxide (NO), generated by exogenous NO-donors, could play a role in the observed IBM of cardioprotection by IPC. Therefore, three distinct NO-donors were investigated at different concentrations (1–10 μM): sodium nitroprusside (SNP), 3-morpholinosydnonimine (SIN-1) and S-nitroso-N-acetylpenicillamine (SNAP). Isolated rat hearts were retrogradely perfused using the Langendorff configuration and subjected to prolonged ischemia and reperfusion with or without pretreatment by NO-donors. Hemodynamic parameters, infarct sizes and proteins of the methionine-centered redox cycle (MCRC) were analyzed, as well as cytosolic aconitase (CA) activity and ferritin protein levels. All NO-donors had significant effects on proteins involved in the MCRC system. Nonetheless, pretreatment with 10 μM SNAP was found to evoke the strongest effects on Msr activity, thioredoxin and thioredoxin reductase protein levels. These effects were accompanied with a significant reduction in infarct size, increased CA activity, and ferritin accumulation. Conversely, pretreatment with 2 μM SIN-1 increased infarct size and was associated with slightly lower ferritin protein levels. In conclusion, the abovementioned findings indicate that NO, depending on its bio-active redox form, can regulate iron metabolism and plays a role in the IBM of cardioprotection against reperfusion injury.
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Affiliation(s)
- Hilbert Grievink
- Department of Biochemistry and Molecular Biology, Hebrew University of Jerusalem, Jerusalem, Israel
- Anesthesiology and Critical Care Medicine, Hebrew University—Hadassah Medical Center, Jerusalem, Israel
| | - Galina Zeltcer
- Department of Biochemistry and Molecular Biology, Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Radiology, Hebrew University—Hadassah Medical Center, Jerusalem, Israel
| | - Benjamin Drenger
- Anesthesiology and Critical Care Medicine, Hebrew University—Hadassah Medical Center, Jerusalem, Israel
| | - Eduard Berenshtein
- Department of Biochemistry and Molecular Biology, Hebrew University of Jerusalem, Jerusalem, Israel
- Electron Microscopy Unit, The Core Research Facility, Hebrew University, Jerusalem, Israel
| | - Mordechai Chevion
- Department of Biochemistry and Molecular Biology, Hebrew University of Jerusalem, Jerusalem, Israel
- * E-mail:
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44
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Abstract
Disrupted brain iron homeostasis is a common feature of neurodegenerative disease. To begin to understand how neuronal iron handling might be involved, we focused on dopaminergic neurons and asked how inactivation of transport proteins affected iron homeostasis in vivo in mice. Loss of the cellular iron exporter, ferroportin, had no apparent consequences. However, loss of transferrin receptor 1, involved in iron uptake, caused neuronal iron deficiency, age-progressive degeneration of a subset of dopaminergic neurons, and motor deficits. There was gradual depletion of dopaminergic projections in the striatum followed by death of dopaminergic neurons in the substantia nigra. Damaged mitochondria accumulated, and gene expression signatures indicated attempted axonal regeneration, a metabolic switch to glycolysis, oxidative stress, and the unfolded protein response. We demonstrate that loss of transferrin receptor 1, but not loss of ferroportin, can cause neurodegeneration in a subset of dopaminergic neurons in mice.
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45
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Abstract
Respiratory disease accounts for a large proportion of emergency admissions to hospital and diseaseassociated mortality. Genetic association studies demonstrate a link between iron metabolism and pulmonary disease phenotypes. IREB2 is a gene that produces iron regulatory protein 2 (IRP2), which has a key role in iron homeostasis. This review addresses pathways involved in iron metabolism, particularly focusing on the role of IREB2. In addition to this, environmental factors also influence phenotypic variation in respiratory disease, for example inhaled iron from cigarette smoke is deposited in the lung and causes tissue damage by altering iron homeostasis. The effects of cigarette smoke are detailed in this article, particularly in relation to lung conditions that favour the upper lobes, such as emphysema and lung cancer. Clinical applications of iron homeostasis are also discussed in this review, especially looking at the pathophysiology of chronic obstructive pulmonary disease, lung cancer, pulmonary infections and acute respiratory distress syndrome. Promising new treatments involving iron are also covered.
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46
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Figueroa-Angulo EE, Calla-Choque JS, Mancilla-Olea MI, Arroyo R. RNA-Binding Proteins in Trichomonas vaginalis: Atypical Multifunctional Proteins. Biomolecules 2015; 5:3354-95. [PMID: 26703754 PMCID: PMC4693282 DOI: 10.3390/biom5043354] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 11/07/2015] [Accepted: 11/12/2015] [Indexed: 01/08/2023] Open
Abstract
Iron homeostasis is highly regulated in vertebrates through a regulatory system mediated by RNA-protein interactions between the iron regulatory proteins (IRPs) that interact with an iron responsive element (IRE) located in certain mRNAs, dubbed the IRE-IRP regulatory system. Trichomonas vaginalis, the causal agent of trichomoniasis, presents high iron dependency to regulate its growth, metabolism, and virulence properties. Although T. vaginalis lacks IRPs or proteins with aconitase activity, possesses gene expression mechanisms of iron regulation at the transcriptional and posttranscriptional levels. However, only one gene with iron regulation at the transcriptional level has been described. Recently, our research group described an iron posttranscriptional regulatory mechanism in the T. vaginalis tvcp4 and tvcp12 cysteine proteinase mRNAs. The tvcp4 and tvcp12 mRNAs have a stem-loop structure in the 5'-coding region or in the 3'-UTR, respectively that interacts with T. vaginalis multifunctional proteins HSP70, α-Actinin, and Actin under iron starvation condition, causing translation inhibition or mRNA stabilization similar to the previously characterized IRE-IRP system in eukaryotes. Herein, we summarize recent progress and shed some light on atypical RNA-binding proteins that may participate in the iron posttranscriptional regulation in T. vaginalis.
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Affiliation(s)
- Elisa E Figueroa-Angulo
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV-IPN), Av. IPN # 2508, Col. San Pedro Zacatenco, CP 07360 México, D.F., Mexico.
| | - Jaeson S Calla-Choque
- Laboratorio de Inmunopatología en Neurocisticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, Urb. Ingeniería, S.M.P., Lima 15102, Peru.
| | - Maria Inocente Mancilla-Olea
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV-IPN), Av. IPN # 2508, Col. San Pedro Zacatenco, CP 07360 México, D.F., Mexico.
| | - Rossana Arroyo
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV-IPN), Av. IPN # 2508, Col. San Pedro Zacatenco, CP 07360 México, D.F., Mexico.
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47
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Abstract
Cellular iron homeostasis is regulated by post-transcriptional feedback mechanisms, which control the expression of proteins involved in iron uptake, release and storage. Two cytoplasmic proteins with mRNA-binding properties, iron regulatory proteins 1 and 2 (IRP1 and IRP2) play a central role in this regulation. Foremost, IRPs regulate ferritin H and ferritin L translation and thus iron storage, as well as transferrin receptor 1 (TfR1) mRNA stability, thereby adjusting receptor expression and iron uptake via receptor-mediated endocytosis of iron-loaded transferrin. In addition splice variants of iron transporters for import and export at the plasma-membrane, divalent metal transporter 1 (DMT1) and ferroportin are regulated by IRPs. These mechanisms have probably evolved to maintain the cytoplasmic labile iron pool (LIP) at an appropriate level. In certain tissues, the regulation exerted by IRPs influences iron homeostasis and utilization of the entire organism. In intestine, the control of ferritin expression limits intestinal iron absorption and, thus, whole body iron levels. In bone marrow, erythroid heme biosynthesis is coordinated with iron availability through IRP-mediated translational control of erythroid 5-aminolevulinate synthase mRNA. Moreover, the translational control of HIF2α mRNA in kidney by IRP1 coordinates erythropoietin synthesis with iron and oxygen supply. Besides IRPs, body iron absorption is negatively regulated by hepcidin. This peptide hormone, synthesized and secreted by the liver in response to high serum iron, downregulates ferroportin at the protein level and thereby limits iron absorption from the diet. Hepcidin will not be discussed in further detail here.
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Affiliation(s)
- Lukas C Kühn
- Ecole Polytechnique Fédérale de Lausanne (EPFL), ISREC - Swiss Institute for Experimental Cancer Research, EPFL_SV_ISREC, Room SV2516, Station 19, CH-1015 Lausanne, Switzerland.
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48
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Guan X, Jiang X, Yang C, Tian X, Li L. The MRI marker geneMagAattenuates the oxidative damage induced by iron overload in transgenic mice. Nanotoxicology 2015; 10:531-41. [DOI: 10.3109/17435390.2015.1090029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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49
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Erythrocytic Iron Deficiency Enhances Susceptibility to Plasmodium chabaudi Infection in Mice Carrying a Missense Mutation in Transferrin Receptor 1. Infect Immun 2015; 83:4322-34. [PMID: 26303393 DOI: 10.1128/iai.00926-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 08/20/2015] [Indexed: 01/26/2023] Open
Abstract
The treatment of iron deficiency in areas of high malaria transmission is complicated by evidence which suggests that iron deficiency anemia protects against malaria, while iron supplementation increases malaria risk. Iron deficiency anemia results in an array of pathologies, including reduced systemic iron bioavailability and abnormal erythrocyte physiology; however, the mechanisms by which these pathologies influence malaria infection are not well defined. In the present study, the response to malaria infection was examined in a mutant mouse line, Tfrc(MRI24910), identified during an N-ethyl-N-nitrosourea (ENU) screen. This line carries a missense mutation in the gene for transferrin receptor 1 (TFR1). Heterozygous mice exhibited reduced erythrocyte volume and density, a phenotype consistent with dietary iron deficiency anemia. However, unlike the case in dietary deficiency, the erythrocyte half-life, mean corpuscular hemoglobin concentration, and intraerythrocytic ferritin content were unchanged. Systemic iron bioavailability was also unchanged, indicating that this mutation results in erythrocytic iron deficiency without significantly altering overall iron homeostasis. When infected with the rodent malaria parasite Plasmodium chabaudi adami, mice displayed increased parasitemia and succumbed to infection more quickly than their wild-type littermates. Transfusion of fluorescently labeled erythrocytes into malaria parasite-infected mice demonstrated an erythrocyte-autonomous enhanced survival of parasites within mutant erythrocytes. Together, these results indicate that TFR1 deficiency alters erythrocyte physiology in a way that is similar to dietary iron deficiency anemia, albeit to a lesser degree, and that this promotes intraerythrocytic parasite survival and an increased susceptibility to malaria in mice. These findings may have implications for the management of iron deficiency in the context of malaria.
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Gassmann M, Muckenthaler MU. Adaptation of iron requirement to hypoxic conditions at high altitude. J Appl Physiol (1985) 2015; 119:1432-40. [PMID: 26183475 DOI: 10.1152/japplphysiol.00248.2015] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 07/10/2015] [Indexed: 12/12/2022] Open
Abstract
Adequate acclimatization time to enable adjustment to hypoxic conditions is one of the most important aspects for mountaineers ascending to high altitude. Accordingly, most reviews emphasize mechanisms that cope with reduced oxygen supply. However, during sojourns to high altitude adjustment to elevated iron demand is equally critical. Thus in this review we focus on the interaction between oxygen and iron homeostasis. We review the role of iron 1) in the oxygen sensing process and erythropoietin (Epo) synthesis, 2) in gene expression control mediated by the hypoxia-inducible factor-2 (HIF-2), and 3) as an oxygen carrier in hemoglobin, myoglobin, and cytochromes. The blood hormone Epo that is abundantly expressed by the kidney under hypoxic conditions stimulates erythropoiesis in the bone marrow, a process requiring high iron levels. To ensure that sufficient iron is provided, Epo-controlled erythroferrone that is expressed in erythroid precursor cells acts in the liver to reduce expression of the iron hormone hepcidin. Consequently, suppression of hepcidin allows for elevated iron release from storage organs and enhanced absorption of dietary iron by enterocytes. As recently observed in sojourners at high altitude, however, iron uptake may be hampered by reduced appetite and gastrointestinal bleeding. Reduced iron availability, as observed in a hypoxic mountaineer, enhances hypoxia-induced pulmonary hypertension and may contribute to other hypoxia-related diseases. Overall, adequate systemic iron availability is an important prerequisite to adjust to high-altitude hypoxia and may have additional implications for disease-related hypoxic conditions.
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Affiliation(s)
- Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland, and Universidad Peruana Cayetano Heredia, Lima, Peru; and
| | - Martina U Muckenthaler
- Pediatric Oncology, Hematology and Immunology, University Hospital Heidelberg, Molecular Medicine Partnership Unit, University of Heidelberg, Translational Lung Research Center Heidelberg, and German Center for Lung Research, Heidelberg, Germany
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