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Yousefi A, Zheng Z, Zargarbashi S, Assadipapari M, Hickman GJ, Parmenter CD, Bueno-Alejo CJ, Sanderson G, Craske D, Xu L, Perry CC, Rahmani M, Ying C. Structural Flexibility and Disassembly Kinetics of Single Ferritin Molecules Using Optical Nanotweezers. ACS NANO 2024; 18:15617-15626. [PMID: 38850556 PMCID: PMC11191739 DOI: 10.1021/acsnano.4c01221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 05/23/2024] [Accepted: 05/31/2024] [Indexed: 06/10/2024]
Abstract
Ferritin, a spherical protein shell assembled from 24 subunits, functions as an efficient iron storage and release system through its channels. Understanding how various chemicals affect the structural behavior of ferritin is crucial for unravelling the origins of iron-related diseases in living organisms including humans. In particular, the influence of chemicals on ferritin's dynamics and iron release is barely explored at the single-protein level. Here, by employing optical nanotweezers using double-nanohole (DNH) structures, we examined the effect of ascorbic acid (reducing reagent) and pH on individual ferritin's conformational dynamics. The dynamics of ferritin increased as the concentration of ascorbic acid approached saturation. At pH 2.0, ferritin exhibited significant structural fluctuations and eventually underwent a stepwise disassembly into fragments. This work demonstrated the disassembly pathway and kinetics of a single ferritin molecule in solution. We identified four critical fragments during its disassembly pathway, which are 22-mer, 12-mer, tetramer, and dimer subunits. Moreover, we present single-molecule evidence of the cooperative disassembly of ferritin. Interrogating ferritin's structural change in response to different chemicals holds importance for understanding their roles in iron metabolism, hence facilitating further development of medical treatments for its associated diseases.
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Affiliation(s)
- Arman Yousefi
- Advanced
Optics and Photonics Laboratory, Department of Engineering, School
of Science and Technology, Nottingham Trent
University, Nottingham NG118NS, United
Kingdom
| | - Ze Zheng
- Advanced
Optics and Photonics Laboratory, Department of Engineering, School
of Science and Technology, Nottingham Trent
University, Nottingham NG118NS, United
Kingdom
| | - Saaman Zargarbashi
- Advanced
Optics and Photonics Laboratory, Department of Engineering, School
of Science and Technology, Nottingham Trent
University, Nottingham NG118NS, United
Kingdom
| | - Mahya Assadipapari
- Advanced
Optics and Photonics Laboratory, Department of Engineering, School
of Science and Technology, Nottingham Trent
University, Nottingham NG118NS, United
Kingdom
| | - Graham J. Hickman
- School
of Science and Technology, Nottingham Trent
University, Nottingham NG11 8NS, United Kingdom
| | | | - Carlos J. Bueno-Alejo
- School
of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - Gabriel Sanderson
- Advanced
Optics and Photonics Laboratory, Department of Engineering, School
of Science and Technology, Nottingham Trent
University, Nottingham NG118NS, United
Kingdom
| | - Dominic Craske
- School
of Science and Technology, Nottingham Trent
University, Nottingham NG11 8NS, United Kingdom
| | - Lei Xu
- Advanced
Optics and Photonics Laboratory, Department of Engineering, School
of Science and Technology, Nottingham Trent
University, Nottingham NG118NS, United
Kingdom
| | - Carole C. Perry
- Interdisciplinary
Biomedical Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham NG11 8NS, United Kingdom
| | - Mohsen Rahmani
- Advanced
Optics and Photonics Laboratory, Department of Engineering, School
of Science and Technology, Nottingham Trent
University, Nottingham NG118NS, United
Kingdom
| | - Cuifeng Ying
- Advanced
Optics and Photonics Laboratory, Department of Engineering, School
of Science and Technology, Nottingham Trent
University, Nottingham NG118NS, United
Kingdom
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2
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Kittilukkana A, Intakhad J, Pilapong C. The role of labile iron on brain proteostasis; could it be an early event of neurodegenerative disease? Arch Biochem Biophys 2024; 756:110020. [PMID: 38692471 DOI: 10.1016/j.abb.2024.110020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/20/2024] [Accepted: 04/27/2024] [Indexed: 05/03/2024]
Abstract
Iron deposits in the brain are a natural consequence of aging. Iron accumulation, especially in the form of labile iron, can trigger a cascade of adverse effects, eventually leading to neurodegeneration and cognitive decline. Aging also increases the dysfunction of cellular proteostasis. The question of whether iron alters proteostasis is now being pondered. Herein, we investigated the effect of ferric citrate, considered as labile iron, on various aspects of proteostasis of neuronal cell lines, and also established an animal model having a labile iron diet in order to evaluate proteostasis alteration in the brain along with behavioral effects. According to an in vitro study, labile iron was found to activate lysosome formation but inhibits lysosomal clearance function. Furthermore, the presence of labile iron can alter autophagic flux and can also induce the accumulation of protein aggregates. RNA-sequencing analysis further reveals the upregulation of various terms related to proteostasis along with neurodegenerative disease-related terms. According to an in vivo study, a labile iron-rich diet does not induce iron overload conditions and was not detrimental to the behavior of male Wistar rats. However, an iron-rich diet can promote iron accumulation in a region-dependent manner. By staining for autophagic markers and misfolding proteins in the cerebral cortex and hippocampus, an iron-rich diet was actually found to alter autophagy and induce an accumulation of misfolding proteins. These findings emphasize the importance of labile iron on brain cell proteostasis, which could be implicated in developing of neurological diseases.
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Affiliation(s)
- Aiyarin Kittilukkana
- Chiang Mai University, Faculty of Associated Medical Sciences, Department of Radiologic Technology, Laboratory of BioMolecular Imaging, Molecular and Cellular Biology, 50200, Chiang Mai, Thailand
| | - Jannarong Intakhad
- Chiang Mai University, Faculty of Associated Medical Sciences, Department of Radiologic Technology, Laboratory of BioMolecular Imaging, Molecular and Cellular Biology, 50200, Chiang Mai, Thailand
| | - Chalermchai Pilapong
- Chiang Mai University, Faculty of Associated Medical Sciences, Department of Radiologic Technology, Laboratory of BioMolecular Imaging, Molecular and Cellular Biology, 50200, Chiang Mai, Thailand.
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3
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Petronek MS, Monga V, Bodeker KL, Kwofie M, Lee CY, Mapuskar KA, Stolwijk JM, Zaher A, Wagner BA, Smith MC, Vollstedt S, Brown H, Chandler ML, Lorack AC, Wulfekuhle JS, Sarkaria JN, Flynn RT, Greenlee JD, Howard MA, Smith BJ, Jones KA, Buettner GR, Cullen JJ, St-Aubin J, Buatti JM, Magnotta VA, Spitz DR, Allen BG. Magnetic Resonance Imaging of Iron Metabolism with T2* Mapping Predicts an Enhanced Clinical Response to Pharmacologic Ascorbate in Patients with GBM. Clin Cancer Res 2024; 30:283-293. [PMID: 37773633 PMCID: PMC10841843 DOI: 10.1158/1078-0432.ccr-22-3952] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 05/22/2023] [Accepted: 09/27/2023] [Indexed: 10/01/2023]
Abstract
PURPOSE Pharmacologic ascorbate (P-AscH-) is hypothesized to be an iron (Fe)-dependent tumor-specific adjuvant to chemoradiation in treating glioblastoma (GBM). This study determined the efficacy of combining P-AscH- with radiation and temozolomide in a phase II clinical trial while simultaneously investigating a mechanism-based, noninvasive biomarker in T2* mapping to predict GBM response to P-AscH- in humans. PATIENTS AND METHODS The single-arm phase II clinical trial (NCT02344355) enrolled 55 subjects, with analysis performed 12 months following the completion of treatment. Overall survival (OS) and progression-free survival (PFS) were estimated with the Kaplan-Meier method and compared across patient subgroups with log-rank tests. Forty-nine of 55 subjects were evaluated using T2*-based MRI to assess its utility as an Fe-dependent biomarker. RESULTS Median OS was estimated to be 19.6 months [90% confidence interval (CI), 15.7-26.5 months], a statistically significant increase compared with historic control patients (14.6 months). Subjects with initial T2* relaxation < 50 ms were associated with a significant increase in PFS compared with T2*-high subjects (11.2 months vs. 5.7 months, P < 0.05) and a trend toward increased OS (26.5 months vs. 17.5 months). These results were validated in preclinical in vitro and in vivo model systems. CONCLUSIONS P-AscH- combined with temozolomide and radiotherapy has the potential to significantly enhance GBM survival. T2*-based MRI assessment of tumor iron content is a prognostic biomarker for GBM clinical outcomes. See related commentary by Nabavizadeh and Bagley, p. 255.
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Affiliation(s)
| | - Varun Monga
- Department of Internal Medicine, Division of Hematology and Oncology, University of Iowa; Iowa City, IA, USA
| | - Kellie L. Bodeker
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
| | - Michael Kwofie
- Department of Radiology, University of Iowa; Iowa City, IA, USA
| | - Chu-Yu Lee
- Department of Radiology, University of Iowa; Iowa City, IA, USA
| | - Kranti A. Mapuskar
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
| | | | - Amira Zaher
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
| | - Brett A. Wagner
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
| | - Mark C. Smith
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
| | - Sandy Vollstedt
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
| | - Heather Brown
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
| | - Meghan L. Chandler
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
| | - Amanda C. Lorack
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
| | | | - Jann N. Sarkaria
- Department of Radiation Oncology, Mayo Clinic; Rochester, MN, USA
| | - Ryan T. Flynn
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
| | | | | | - Brian J. Smith
- Department of Biostatistics, University of Iowa; Iowa City, IA, USA
| | - Karra A. Jones
- Department of Pathology, Division of Neuropathology, Duke University; Durham, NC, USA
| | - Garry R. Buettner
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
| | | | - Joel St-Aubin
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
| | - John M. Buatti
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
| | | | - Douglas R. Spitz
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
| | - Bryan G. Allen
- Department of Radiation Oncology, University of Iowa; Iowa City, IA, USA
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4
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Petronek MS, Teferi N, Lee CY, Magnotta VA, Allen BG. MRI Detection and Therapeutic Enhancement of Ferumoxytol Internalization in Glioblastoma Cells. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:189. [PMID: 38251153 PMCID: PMC10821426 DOI: 10.3390/nano14020189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 01/23/2024]
Abstract
Recently, the FDA-approved iron oxide nanoparticle, ferumoxytol, has been found to enhance the efficacy of pharmacological ascorbate (AscH-) in treating glioblastoma, as AscH- reduces the Fe3+ sites in the nanoparticle core. Given the iron oxidation state specificity of T2* relaxation mapping, this study aims to investigate the ability of T2* relaxation to monitor the reduction of ferumoxytol by AscH- with respect to its in vitro therapeutic enhancement. This study employed an in vitro glioblastoma MRI model system to investigate the chemical interaction of ferumoxytol with T2* mapping. Lipofectamine was utilized to facilitate ferumoxytol internalization and assess intracellular versus extracellular chemistry. In vitro T2* mapping successfully detected an AscH--mediated reduction of ferumoxytol (25.6 ms versus 2.8 ms for FMX alone). The T2* relaxation technique identified the release of Fe2+ from ferumoxytol by AscH- in glioblastoma cells. However, the high iron content of ferumoxytol limited T2* ability to differentiate between the external and internal reduction of ferumoxytol by AscH- (ΔT2* = +839% for external FMX and +1112% for internal FMX reduction). Notably, the internalization of ferumoxytol significantly enhances its ability to promote AscH- toxicity (dose enhancement ratio for extracellular FMX = 1.16 versus 1.54 for intracellular FMX). These data provide valuable insights into the MR-based nanotheranostic application of ferumoxytol and AscH- therapy for glioblastoma management. Future developmental efforts, such as FMX surface modifications, may be warranted to enhance this approach further.
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Affiliation(s)
- Michael S. Petronek
- Department of Radiation Oncology, University of Iowa, Iowa City, IA 52242, USA
| | - Nahom Teferi
- Department of Neurosurgery, University of Iowa, Iowa City, IA 52242, USA;
| | - Chu-Yu Lee
- Department of Radiology, University of Iowa, Iowa City, IA 52242, USA (V.A.M.)
| | - Vincent A. Magnotta
- Department of Radiology, University of Iowa, Iowa City, IA 52242, USA (V.A.M.)
| | - Bryan G. Allen
- Department of Radiation Oncology, University of Iowa, Iowa City, IA 52242, USA
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5
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Abedi H, Shahpiri A. Functional characterization of a manganese superoxide dismutase from Avicennia marina: insights into its role in salt, hydrogen peroxide, and heavy metal tolerance. Sci Rep 2024; 14:406. [PMID: 38172216 PMCID: PMC10764323 DOI: 10.1038/s41598-023-50851-5] [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: 05/29/2023] [Accepted: 12/27/2023] [Indexed: 01/05/2024] Open
Abstract
Avicennia marina is a salt-tolerance plant with high antioxidant and antibacterial potential. In the present work, a gene encoding MnSOD from Avicennia marina (AmSOD2) was cloned in the expression vectors pET28a. The resulting constructs were transformed into Escherichia coli strains Rosetta (DE3). Following the induction with Isopropyl β-D-1-thiogalactopyranoside, the protein His-AmSOD2 was expressed but dominantly found in the insoluble fraction of strain R-AmSOD2. Due to detection of mitochondrial transit peptide in the amino acid sequence of AmSOD2, the transit peptide was removed and AmSOD2 without transit peptide (tAmSOD2) was expressed in E. coli and dominantly found in the soluble fraction. The enzyme His-tAmSOD2 exhibited a molecular mass of 116 kDa in native condition. Nevertheless, in reducing conditions the molecular mass is 28 kDa indicating the enzyme His-tAmSOD2 is a tetramer protein. As shown by ICP analysis there is one mole Mn2+ in each monomer. The Pure His-tAmSOD2 was highly active in vitro, however the activity was almost three-fold lower than His-AmSOD1. Whereas the high stability of the recombinant His-AmSOD1was previously shown after incubation in a broad range pH and high temperature, His-tAmSOD2 was stable up to 50 °C and pH 6 for 1 h. The gene expression analysis showed that the gene encoding AmSOD2 is expressed in root, shoot and leaves of A. marina. In addition, the results show that the expression in the leaves was enhanced after treatment of plant with NaCl, H2O2, Cd2+ and Ni2+ indicating the important role of MnSOD in the resistant mechanism of mangroves.
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Affiliation(s)
- Hamid Abedi
- Department of Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran
| | - Azar Shahpiri
- Department of Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
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6
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Leischner C, Marongiu L, Piotrowsky A, Niessner H, Venturelli S, Burkard M, Renner O. Relevant Membrane Transport Proteins as Possible Gatekeepers for Effective Pharmacological Ascorbate Treatment in Cancer. Antioxidants (Basel) 2023; 12:antiox12040916. [PMID: 37107291 PMCID: PMC10135768 DOI: 10.3390/antiox12040916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/23/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
Despite the increasing number of newly diagnosed malignancies worldwide, therapeutic options for some tumor diseases are unfortunately still limited. Interestingly, preclinical but also some clinical data suggest that the administration of pharmacological ascorbate seems to respond well, especially in some aggressively growing tumor entities. The membrane transport and channel proteins are highly relevant for the use of pharmacological ascorbate in cancer therapy and are involved in the transfer of active substances such as ascorbate, hydrogen peroxide, and iron that predominantly must enter malignant cells to induce antiproliferative effects and especially ferroptosis. In this review, the relevant conveying proteins from cellular surfaces are presented as an integral part of the efficacy of pharmacological ascorbate, considering the already known genetic and functional features in tumor tissues. Accordingly, candidates for diagnostic markers and therapeutic targets are mentioned.
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Affiliation(s)
- Christian Leischner
- Institute of Nutritional Sciences, Department of Nutritional Biochemistry, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany
| | - Luigi Marongiu
- Institute of Nutritional Sciences, Department of Nutritional Biochemistry, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany
- Department of Internal Medicine VIII, University Hospital Tuebingen, Otfried-Mueller-Straße 10, 72076 Tuebingen, Germany
| | - Alban Piotrowsky
- Institute of Nutritional Sciences, Department of Nutritional Biochemistry, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany
| | - Heike Niessner
- Department of Dermatology, Division of Dermatooncology, University of Tuebingen, Liebermeisterstraße 25, 72076 Tuebingen, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image Guided and Functionally Instructed Tumor Therapies", 72076 Tuebingen, Germany
| | - Sascha Venturelli
- Institute of Nutritional Sciences, Department of Nutritional Biochemistry, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany
- Institute of Physiology, Department of Vegetative and Clinical Physiology, University of Tuebingen, Wilhelmstraße 56, 72074 Tuebingen, Germany
| | - Markus Burkard
- Institute of Nutritional Sciences, Department of Nutritional Biochemistry, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany
| | - Olga Renner
- Institute of Nutritional Sciences, Department of Nutritional Biochemistry, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany
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7
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Hu Z, Li Y, Ma B, Lei S, Wang X. Iron metabolism mediates the relationship between Vitamin C and hepatic steatosis and fibrosis in NAFLD. Front Nutr 2022; 9:952056. [PMID: 36159474 PMCID: PMC9494736 DOI: 10.3389/fnut.2022.952056] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/18/2022] [Indexed: 11/13/2022] Open
Abstract
Vitamin C (Vit C) and iron metabolism are closely related to metabolic disorders. However, the relation between iron storage protein ferritin and Vit C has not been elucidated. We aimed to investigate the crosstalk between Vit C and ferritin and its implications on non-alcoholic fatty liver disease (NAFLD). Clinical information of 3,614 subjects was obtained from the NHANES Public Data 2017–2018. FibroScan data, which estimates liver steatosis and fibrosis and Vit C, were selected to assess factors influencing NAFLD in this cross-sectional study. Ferritin and Vit C among different categories of liver steatosis and fibrosis were assessed by CAP and E value. Logistic regression and RCS models were used to analyze the correlations. In vitro study in hepG2 were conducted to validate the regulations. Ferritin increased while Vit C decreased with more severe hepatic steatosis and hepatic fibrosis (all P < 0.001). Logistic regression models indicated that increased serum ferritin was a risk factor for NAFLD while increased Vit C was a protective factor for NAFLD and hepatic fibrosis after adjusting the continuous and categorical variables. Vitamin C was negatively associated with ferritin. Further mediation analysis identified that ferritin mediates the impact of Vit C on NAFLD (P < 0.05) and cirrhosis (P < 0.001). The experiments on cellular level suggested Vit C alleviated PA/OA induced steatosis and maintains iron homeostasis through inhibiting PA/OA induced upregulation of iron bound protein ferritin and labile iron pool (LIP) induction in hepG2 cells. In conclusion, Vit C was a protective factor, whereas ferritin was a risk factor for hepatic steatosis and fibrosis. Vitamin C alleviated NAFLD and maintained iron homeostasis via ferritin suppression and LIP induction.
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Affiliation(s)
- Zhengyu Hu
- Department of General Surgery, Shanghai Tenth People's Hospital, Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Yan Li
- Department of Gastroenterology, Shanghai Tenth People's Hospital, Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Bingwei Ma
- Department of General Surgery, Shanghai Tenth People's Hospital, Affiliated to Tongji University School of Medicine, Shanghai, China
| | - Saifei Lei
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA, United States
| | - Xingchun Wang
- Department of Endocrinology and Metabolism, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, Shanghai, China
- *Correspondence: Xingchun Wang
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8
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Ni Y, Wu GH, Cai JJ, Zhang R, Zheng Y, Liu JQ, Yang XH, Yang X, Shen Y, Lai JM, Ye XM, Mo SJ. Tubule-mitophagic secretion of SerpinG1 reprograms macrophages to instruct anti-septic acute kidney injury efficacy of high-dose ascorbate mediated by NRF2 transactivation. Int J Biol Sci 2022; 18:5168-5184. [PMID: 35982894 PMCID: PMC9379417 DOI: 10.7150/ijbs.74430] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 07/26/2022] [Indexed: 11/06/2022] Open
Abstract
High-dose ascorbate confers tubular mitophagy responsible for septic acute kidney injury (AKI) amelioration, yet its biological roles in immune regulation remain poorly understood. Methods: The role of tubular mitophagy in macrophage polarization upon high-dose ascorbate treatment was assessed by fluorescence-activated cell sorter analysis (FACS) in vitro and by immunofluorescence in AKI models of LPS-induced endotoxemia (LIE) from Pax8-cre; Atg7flox/flox mice. The underlying mechanisms were revealed by RNA-sequencing, gene set enrichment analysis (GSEA), luciferase reporter, chromatin immunoprecipitation (ChIP) and adeno-associated viral vector serotype 9 (AAV9) delivery assays. Results: High-dose ascorbate enables conversion of macrophages from a pro-inflammatory M1 subtype to an anti-inflammatory M2 subtype in murine AKI models of LIE, leading to decreased renal IL-1β and IL-18 production, reduced mortality and alleviated tubulotoxicity. Blockade of tubular mitophagy abrogates anti-inflammatory macrophages polarization under the high-dose ascorbate-exposed coculture systems. Similar abrogations are verified in LIE mice with tubular epithelium-specific ablation of Atg7, where the high-dose ascorbate-inducible renal protection and survival improvement are substantially weaker than their control littermates. Mechanistically, high-dose ascorbate stimulates tubular secretion of serpin family G member 1 (SerpinG1) through maintenance of mitophagy, for which nuclear factor-erythroid 2 related factor 2 (NRF2) transactivation is required. SerpinG1 perpetuates anti-inflammatory macrophages to prevent septic AKI, while kidney-specific disruption of SerpinG1 by adeno-associated viral vector serotype 9 (AAV9)-short hairpin RNA (shRNA) delivery thwarts the anti-inflammatory macrophages polarization and anti-septic AKI efficacy of high-dose ascorbate. Conclusion: Our study identifies SerpinG1 as an intermediate of tubular mitophagy-orchestrated myeloid function during septic AKI and reveals a novel rationale for ascorbate-based therapy.
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Affiliation(s)
- Yin Ni
- Emergency and Intensive Care Unit Center, Department of Intensive Care Unit, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China
| | - Guo-Hua Wu
- Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310029, Zhejiang, P.R.China
| | - Juan-Juan Cai
- Department of Pathology, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China
| | - Run Zhang
- Emergency and Intensive Care Unit Center, Department of Intensive Care Unit, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China
| | - Yang Zheng
- Emergency and Intensive Care Unit Center, Department of Intensive Care Unit, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China
| | - Jing-Quan Liu
- Emergency and Intensive Care Unit Center, Department of Intensive Care Unit, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China
| | - Xiang-Hong Yang
- Emergency and Intensive Care Unit Center, Department of Intensive Care Unit, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China
| | - Xue Yang
- Clinical Research Institute, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China
| | - Ye Shen
- Center for Rehabilitation Medicine, Department of Intensive Rehabilitation Care Unit, Zhejiang P rovincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China.,Center for Rehabilitation Medicine, Rehabilitation & Sports Medicine Research Institute of Zhejiang Province, Department of Rehabilitation Medicine, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China
| | - Jun-Mei Lai
- Center for Rehabilitation Medicine, Department of Intensive Rehabilitation Care Unit, Zhejiang P rovincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China.,Center for Rehabilitation Medicine, Rehabilitation & Sports Medicine Research Institute of Zhejiang Province, Department of Rehabilitation Medicine, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China
| | - Xiang-Ming Ye
- Center for Rehabilitation Medicine, Department of Intensive Rehabilitation Care Unit, Zhejiang P rovincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China.,Center for Rehabilitation Medicine, Rehabilitation & Sports Medicine Research Institute of Zhejiang Province, Department of Rehabilitation Medicine, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China
| | - Shi-Jing Mo
- Emergency and Intensive Care Unit Center, Department of Intensive Care Unit, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China.,Center for Rehabilitation Medicine, Department of Intensive Rehabilitation Care Unit, Zhejiang P rovincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China.,Center for Rehabilitation Medicine, Rehabilitation & Sports Medicine Research Institute of Zhejiang Province, Department of Rehabilitation Medicine, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, Zhejiang, P.R.China
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9
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Viktorinova A, Durfinova M. Mini-Review: Is iron-mediated cell death (ferroptosis) an identical factor contributing to the pathogenesis of some neurodegenerative diseases? Neurosci Lett 2021; 745:135627. [PMID: 33440237 DOI: 10.1016/j.neulet.2021.135627] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/18/2020] [Accepted: 01/02/2021] [Indexed: 12/23/2022]
Abstract
The review article briefly discusses a hypothesis based on the potential participation of iron dyshomeostasis and iron-mediated cell death (ferroptosis) in the pathogenesis of some neurodegenerative diseases. Iron dyshomeostasis (especially cellular iron overload) is considered to be a critical condition of neurodegeneration. The etiopathogenesis of many neurodegenerative diseases including Alzheimer's and Parkinson's diseases, Multiple sclerosis, and others, is different. However, there are several identical cellular processes, such as iron dyshomeostasis (an excessive iron deposition), iron-induced oxidative stress, the accumulation of lipid-generated reactive oxygen species, and ferroptosis that accompany these diseases. Based on the existing theoretical and experimental evidence, the article provides current insight into iron dyshomeostasis and ferroptosis as a contributing factor to the pathogenesis of neurodegeneration. In addition, special attention is addressed to the possible relationship between cellular iron overload and key pathological features of selected neurodegenerative diseases, such as β-amyloid and tau proteins, α-synuclein, and demyelination. The mechanism by which ferroptosis may be involved in the pathogenesis of various neurodegenerative diseases is not fully elucidated. Further experimental and clinical studies are needed to clarify the hypothesis on the potential role of ferroptosis in the pathogenesis of neurodegenerative diseases.
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Affiliation(s)
- Alena Viktorinova
- Institute of Medical Chemistry, Biochemistry and Clinical Biochemistry, Faculty of Medicine, Comenius University, Bratislava, Slovakia.
| | - Monika Durfinova
- Institute of Medical Chemistry, Biochemistry and Clinical Biochemistry, Faculty of Medicine, Comenius University, Bratislava, Slovakia
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10
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Smith MJ, Fowler M, Naftalin RJ, Siow RCM. UVA irradiation increases ferrous iron release from human skin fibroblast and endothelial cell ferritin: Consequences for cell senescence and aging. Free Radic Biol Med 2020; 155:49-57. [PMID: 32387586 DOI: 10.1016/j.freeradbiomed.2020.04.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 04/26/2020] [Indexed: 12/13/2022]
Abstract
UVA irradiation of human dermal fibroblasts and endothelial cells induces an immediate transient increase in cytosolic Fe(II), as monitored by the fluorescence Fe(II) reporters, FeRhonox1 in cytosol and MitoFerroGreen in mitochondria. Both superoxide dismutase (SOD) inhibition by tetrathiomolybdate (ATM) and catalase inhibition by 3-amino-1, 2, 4-triazole (ATZ) increase and prolong the cytosolic Fe(II) signal after UVA irradiation. SOD inhibition with ATM also increases mitochondrial Fe(II). Thus, mitochondria do not source the UV-dependent increase in cytosolic Fe(II), but instead reflect and amplify raised cytosolic labile Fe(II) concentration. Hence control of cytosolic ferritin iron release is key to preventing UVA-induced inflammation. UVA irradiation also increases dermal endothelial cell H2O2, as monitored by the adenovirus vector Hyper-DAAO-NES(HyPer). These UVA-dependent changes in intracellular Fe(II) and H2O2 are mirrored by increases in cell superoxide, monitored with the luminescence probe L-012. UV-dependent increases in cytosolic Fe(II), H2O2 and L-012 chemiluminescence are prevented by ZnCl2 (10 μM), an effective inhibitor of Fe(II) transport via ferritin's 3-fold channels. Quercetin (10 μM), a potent membrane permeable Fe(II) chelator, abolishes the cytosolic UVA-dependent FeRhonox1, Fe(II) and HyPer, H2O2 and increase in MitoFerroGreen Fe(II) signals. The time course of the quercetin-dependent decrease in endothelial H2O2 correlates with the decrease in FeRhox1 signal and both signals are fully suppressed by preloading cells with ZnCl2. These results confirm that antioxidant enzyme activity is the key factor in controlling intracellular iron levels, and hence maintenance of cell antioxidant capacity is vitally important in prevention of skin aging and inflammation initiated by labile iron and UVA.
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Affiliation(s)
- Matthew J Smith
- King's BHF Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, 150 Stamford Street, London, SE1 9NH, UK
| | - Mark Fowler
- Unilever Colworth Science Park, Bedfordshire, UK
| | - Richard J Naftalin
- King's BHF Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, 150 Stamford Street, London, SE1 9NH, UK.
| | - Richard C M Siow
- King's BHF Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, 150 Stamford Street, London, SE1 9NH, UK
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11
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Murgas CJ, Green SP, Forney AK, Korba RM, An SS, Kitten T, Lucas HR. Intracellular Metal Speciation in Streptococcus sanguinis Establishes SsaACB as Critical for Redox Maintenance. ACS Infect Dis 2020; 6:1906-1921. [PMID: 32329608 DOI: 10.1021/acsinfecdis.0c00132] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Streptococcus sanguinis is an oral commensal bacterium, but it can colonize pre-existing heart valve vegetations if introduced into the bloodstream, leading to infective endocarditis. Loss of Mn- or Fe-cofactored virulence determinants are thought to result in weakening of this bacterium. Indeed, intracellular Mn accumulation mediated by the lipoprotein SsaB, a component of the SsaACB transporter complex, has been shown to promote virulence for endocarditis and O2 tolerance. To delineate intracellular metal-ion abundance and redox speciation within S. sanguinis, we developed a protocol exploiting two spectroscopic techniques, Inductively coupled plasma-optical emission spectrometry (ICP-OES) and electron paramagnetic resonance (EPR) spectroscopy, to respectively quantify total intracellular metal concentrations and directly measure redox speciation of Fe and Mn within intact whole-cell samples. Addition of the cell-permeable siderophore deferoxamine shifts the oxidation states of accessible Fe and Mn from reduced-to-oxidized, as verified by magnetic moment calculations, aiding in the characterization of intracellular metal pools and metal sequestration levels for Mn2+ and Fe. We have applied this methodology to S. sanguinis and an SsaACB knockout strain (ΔssaACB), indicating that SsaACB mediates both Mn and Fe uptake, directly influencing the metal-ion pools available for biological inorganic pathways. Mn supplementation of ΔssaACB returns total intracellular Mn to wild-type levels, but it does not restore wild-type redox speciation or distribution of metal cofactor availability for either Mn or Fe. Our results highlight the biochemical basis for S. sanguinis oxidative resistance, revealing a dynamic role for SsaACB in controlling redox homeostasis by managing the intracellular Fe/Mn composition and distribution.
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Affiliation(s)
- Cody J. Murgas
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Shannon P. Green
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia 23298, United States
- Department of Microbiology & Immunology, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Ashley K. Forney
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Rachel M. Korba
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Seon-Sook An
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Todd Kitten
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia 23298, United States
- Department of Microbiology & Immunology, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Heather R. Lucas
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
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12
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Zhou L, Zhang L, Wang S, Zhao B, Lv H, Shang P. Labile iron affects pharmacological ascorbate-induced toxicity in osteosarcoma cell lines. Free Radic Res 2020; 54:385-396. [PMID: 32183598 DOI: 10.1080/10715762.2020.1744577] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Vitamin C and iron are both important nutrients for humans and involved in several physiological processes. The biological activities of vitamin C and iron are based on their abilities to accept or donate electrons. Although vitamin C is well known as an excellent electron donor in physiological conditions, it also has pro-oxidant properties, especially with catalytic metal iron. Cancer cells have a higher iron requirement than normal cells, which allows pharmacological ascorbate to kill cancer cells selectively. In this study, we demonstrated that the levels of H2O2 in cells were significantly raised after treated with pharmacological ascorbate, and intracellular labile iron could increase pharmacological ascorbate-mediated oxidative stress by Fenton reaction. Catalytic metal iron plays opposite roles in and outside cells. Intracellular excess labile iron improved ascorbate-induced toxicity, while the excess labile iron in the medium abolished ascorbate-induced toxicity. Fe3+ and Fe2+ have the same effect on ascorbate-induced toxicity, but Fe3+ chelator deferoxamine (DFO) has a profound inhibition effect than Fe2+ chelator 2,2'-bipyridyl (BIP) on ascorbate-induced toxicity. The influence of intracellular labile iron and ascorbate on the ferritin expression may cause selective sensitivity in osteosarcoma cell lines on pharmacological ascorbate. High iron requirement of many cancer cells facilitates pharmacological ascorbate on cancer treatment. In addition, increasing iron content in tumour tissue may be effective strategies to improve the effects of pharmacological ascorbate.
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Affiliation(s)
- Liangfu Zhou
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Lixiu Zhang
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Shenghang Wang
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Bin Zhao
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Huanhuan Lv
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.,Research and Development Institute, Northwestern Polytechnical University in Shenzhen, Shenzhen, China.,Key Laboratory for Space Bioscience and Biotechnology, Institute of Special Environment Biophysics, Northwestern Polytechnical University, Xi'an, China
| | - Peng Shang
- Research and Development Institute, Northwestern Polytechnical University in Shenzhen, Shenzhen, China.,Key Laboratory for Space Bioscience and Biotechnology, Institute of Special Environment Biophysics, Northwestern Polytechnical University, Xi'an, China
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13
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Przybyło M, Langner M. On the physiological and cellular homeostasis of ascorbate. Cell Mol Biol Lett 2020; 25:32. [PMID: 32514268 PMCID: PMC7257198 DOI: 10.1186/s11658-020-00223-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 04/30/2020] [Indexed: 02/07/2023] Open
Abstract
Recent interest in the role of ascorbate in crucial metabolic processes is driven by the growing number of medical reports that show beneficial effects of ascorbate supplementation for maintaining general well-being and recovery from a variety of medical conditions. The effect of ascorbate on the local body environment highly depends on its local concentration; at low concentrations it can cause the reduction of reactive oxygen and facilitate activities of enzymes, while at high concentrations it generates free radicals by reducing ferric ions. Ascorbate serving as an electron donor assists the iron-containing proteins and the iron transfer between various aqueous compartments. These functions require effective and adjustable mechanisms responsible for ascorbate biodistribution. In the paper we propose a new biophysical model of ascorbate redistribution between various aqueous body compartments. It combines recent experimental evidence regarding the ability of ascorbate to cross the lipid bilayer by unassisted diffusion, with active transport by well-characterized sodium vitamin C transporter (SVCT) membrane proteins. In the model, the intracellular concentration of ascorbate is maintained by the balance of two opposing fluxes: fast active and slow passive transport. The model provides a mechanistic understanding of ascorbate flux across the epidermal barrier in the gut as well as the role of astrocytes in ascorbate recycling in the brain. In addition, ascorbate passive diffusion across biological membranes, which depends on membrane electric potentials and pH gradients, provides the rationale for the correlation between ascorbate distribution and the transfer of iron ions inside a cell. The proposed approach provides, for the first time, a mechanistic account of processes leading to ascorbate physiological and cellular distribution, which helps to explain numerous experimental and clinical observations.
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Affiliation(s)
- Magdalena Przybyło
- Faculty of Biomedical Engineering, Wrocław University of Sciences and Technology, 50-370 Wrocław, Poland
- Lipid Systems Ltd, Krzemieniecka 48C, 54-613 Wrocław, Poland
| | - Marek Langner
- Faculty of Biomedical Engineering, Wrocław University of Sciences and Technology, 50-370 Wrocław, Poland
- Lipid Systems Ltd, Krzemieniecka 48C, 54-613 Wrocław, Poland
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14
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Muhoberac BB, Vidal R. Iron, Ferritin, Hereditary Ferritinopathy, and Neurodegeneration. Front Neurosci 2019; 13:1195. [PMID: 31920471 PMCID: PMC6917665 DOI: 10.3389/fnins.2019.01195] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 10/21/2019] [Indexed: 12/31/2022] Open
Abstract
Cellular growth, function, and protection require proper iron management, and ferritin plays a crucial role as the major iron sequestration and storage protein. Ferritin is a 24 subunit spherical shell protein composed of both light (FTL) and heavy chain (FTH1) subunits, possessing complimentary iron-handling functions and forming three-fold and four-fold pores. Iron uptake through the three-fold pores is well-defined, but the unloading process somewhat less and generally focuses on lysosomal ferritin degradation although it may have an additional, energetically efficient pore mechanism. Hereditary Ferritinopathy (HF) or neuroferritinopathy is an autosomal dominant neurodegenerative disease caused by mutations in the FTL C-terminal sequence, which in turn cause disorder and unraveling at the four-fold pores allowing iron leakage and enhanced formation of toxic, improperly coordinated iron (ICI). Histopathologically, HF is characterized by iron deposition and formation of ferritin inclusion bodies (IBs) as the cells overexpress ferritin in an attempt to address iron accumulation while lacking the ability to clear ferritin and its aggregates. Overexpression and IB formation tax cells materially and energetically, i.e., their synthesis and disposal systems, and may hinder cellular transport and other spatially dependent functions. ICI causes cellular damage to proteins and lipids through reactive oxygen species (ROS) formation because of high levels of brain oxygen, reductants and metabolism, taxing cellular repair. Iron can cause protein aggregation both indirectly by ROS-induced protein modification and destabilization, and directly as with mutant ferritin through C-terminal bridging. Iron release and ferritin degradation are also linked to cellular misfunction through ferritinophagy, which can release sufficient iron to initiate the unique programmed cell death process ferroptosis causing ROS formation and lipid peroxidation. But IB buildup suggests suppressed ferritinophagy, with elevated iron from four-fold pore leakage together with ROS damage and stress leading to a long-term ferroptotic-like state in HF. Several of these processes have parallels in cell line and mouse models. This review addresses the roles of ferritin structure and function within the above-mentioned framework, as they relate to HF and associated disorders characterized by abnormal iron accumulation, protein aggregation, oxidative damage, and the resulting contributions to cumulative cellular stress and death.
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Affiliation(s)
- Barry B. Muhoberac
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Ruben Vidal
- Department of Pathology and Laboratory Medicine, Indiana Alzheimer Disease Center, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
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15
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Koppenol WH, Hider RH. Iron and redox cycling. Do's and don'ts. Free Radic Biol Med 2019; 133:3-10. [PMID: 30236787 DOI: 10.1016/j.freeradbiomed.2018.09.022] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 09/01/2018] [Accepted: 09/14/2018] [Indexed: 12/23/2022]
Abstract
A major form of toxicity arises from the ability of iron to redox cycle, that is, to accept an electron from a reducing compound and to pass it on to H2O2 (the Fenton reaction). In order to do so, iron must be suitably complexed to avoid formation of Fe2O3. The ligands determine the electrode potential; this information should be known before experiments are carried out. Only one-electron transfer reactions are likely to be significant; thus two-electron potentials should not be used to determine whether an iron(III) complex can be reduced or oxidized. Ascorbate is the relevant reducing agent in blood serum, which means that iron toxicity in this compartment arises from the ascorbate-driven Fenton reaction. In the cytosol, an iron(II)-glutathione complex is likely to be the low-molecular weight iron complex involved in toxicity. When physiologically relevant concentrations are used the window of redox opportunity ranges from +0.1 V to +0.9 V. The electrode potential for non-transferrin-bound iron in the form of iron citrate is close to 0 V and the reduction of iron(III) citrate by ascorbate is slow. The clinically utilised chelators desferrioxamine, deferiprone and deferasirox in each case render iron complexes with large negative electrode potentials, thus being effective in preventing iron redox cycling and the associated toxicity resulting from such activity. There is still uncertainty about the product of the Fenton reaction, HO• or FeO2+.
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Affiliation(s)
- W H Koppenol
- Schwändibergstrasse 25, CH-8784 Braunwald, Switzerland; Emeritus, Department of Chemistry and Applied Biosciences, ETHZ, CH-8093 Zürich, Switzerland.
| | - R H Hider
- Department of Pharmacy, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
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16
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Badu-Boateng C, Naftalin RJ. Ascorbate and ferritin interactions: Consequences for iron release in vitro and in vivo and implications for inflammation. Free Radic Biol Med 2019; 133:75-87. [PMID: 30268889 DOI: 10.1016/j.freeradbiomed.2018.09.041] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 01/19/2023]
Abstract
This review discusses the chemical mechanisms of ascorbate-dependent reduction and solubilization of ferritin's ferric iron core and subsequent release of ferrous iron. The process is accelerated by low concentrations of Fe(II) that increase ferritin's intrinsic ascorbate oxidase activity, hence increasing the rate of ascorbate radical formation. These increased rates of ascorbate oxidation provide reducing equivalents (electrons) to ferritin's core and speed the core reduction rates with subsequent solubilization and release of Fe(II). Ascorbate-dependent solubilization of ferritin's iron core has consequences relating to the interpretation of 59Fe uptake sourced from 59Fe-lebelled holotransferrin into ferritin. Ascorbate-dependent reduction of the ferritin core iron solubility increases the size of ferritin's iron exchangeable pool and hence the rate and amount of exchange uptake of 59Fe into ferritin, whilst simultaneously increasing net iron release rate from ferritin. This may rationalize the inconsistency that ascorbate apparently stabilizes 59Fe ferritin and retards lysosomal ferritinolysis and whole cell 59Fe release, whilst paradoxically increasing the rate of net iron release from ferritin. This capacity of ascorbate and iron to synergise ferritin iron release has pathological significance, as it lowers the concentration at which ascorbate activates ferritin's iron release to within the physiological range (50-250 μM). These effects have relevance to inflammatory pathology and to the pro-oxidant effects of ascorbate in cancer therapy and cell death by ferroptosis.
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Affiliation(s)
- Charles Badu-Boateng
- Kings, BHF Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Richard J Naftalin
- Kings, BHF Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London SE1 9NH, UK
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17
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Koochana PK, Mohanty A, Subhadarshanee B, Satpati S, Naskar R, Dixit A, Behera RK. Phenothiazines and phenoxazines: as electron transfer mediators for ferritin iron release. Dalton Trans 2019; 48:3314-3326. [DOI: 10.1039/c8dt04383c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Redox active phenothiazine and phenoxazine dyes facilitate ferritin iron release by acting as electron transfer (ET) mediators following Marcus theory.
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Affiliation(s)
| | - Abhinav Mohanty
- Department of Chemistry
- National Institute of Technology
- Rourkela-769008
- India
| | | | - Suresh Satpati
- Institute of Life Sciences
- Bhubaneswar-751023
- India
- Indian Institute of Science
- Bangalore-560012
| | - Rajat Naskar
- Department of Chemistry
- National Institute of Technology
- Rourkela-769008
- India
| | | | - Rabindra K. Behera
- Department of Chemistry
- National Institute of Technology
- Rourkela-769008
- India
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18
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Reductive Mobilization of Iron from Intact Ferritin: Mechanisms and Physiological Implication. Pharmaceuticals (Basel) 2018; 11:ph11040120. [PMID: 30400623 PMCID: PMC6315955 DOI: 10.3390/ph11040120] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 01/18/2023] Open
Abstract
Ferritins are highly conserved supramolecular protein nanostructures composed of two different subunit types, H (heavy) and L (light). The two subunits co-assemble into a 24-subunit heteropolymer, with tissue specific distributions, to form shell-like protein structures within which thousands of iron atoms are stored as a soluble inorganic ferric iron core. In-vitro (or in cell free systems), the mechanisms of iron(II) oxidation and formation of the mineral core have been extensively investigated, although it is still unclear how iron is loaded into the protein in-vivo. In contrast, there is a wide spread belief that the major pathway of iron mobilization from ferritin involves a lysosomal proteolytic degradation of ferritin, and the dissolution of the iron mineral core. However, it is still unclear whether other auxiliary iron mobilization mechanisms, involving physiological reducing agents and/or cellular reductases, contribute to the release of iron from ferritin. In vitro iron mobilization from ferritin can be achieved using different reducing agents, capable of easily reducing the ferritin iron core, to produce soluble ferrous ions that are subsequently chelated by strong iron(II)-chelating agents. Here, we review our current understanding of iron mobilization from ferritin by various reducing agents, and report on recent results from our laboratory, in support of a mechanism that involves a one-electron transfer through the protein shell to the iron mineral core. The physiological significance of the iron reductive mobilization from ferritin by the non-enzymatic FMN/NAD(P)H system is also discussed.
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Smirnoff N. Ascorbic acid metabolism and functions: A comparison of plants and mammals. Free Radic Biol Med 2018; 122:116-129. [PMID: 29567393 PMCID: PMC6191929 DOI: 10.1016/j.freeradbiomed.2018.03.033] [Citation(s) in RCA: 275] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 03/15/2018] [Accepted: 03/17/2018] [Indexed: 02/07/2023]
Abstract
Ascorbic acid is synthesised by eukaryotes, the known exceptions being primates and some other animal groups which have lost functional gulonolactone oxidase. Prokaryotes do not synthesise ascorbate and do not need an ascorbate supply, so the functions that are essential for mammals and plants are not required or are substituted by other compounds. The ability of ascorbate to donate electrons enables it to act as a free radical scavenger and to reduce higher oxidation states of iron to Fe2+. These reactions are the basis of its biological activity along with the relative stability of the resulting resonance stabilised monodehydroascorbate radical. The importance of these properties is emphasised by the evolution of at least three biosynthetic pathways and production of an ascorbate analogue, erythroascorbate, by fungi. The iron reducing activity of ascorbate maintains the reactive centre Fe2+ of 2-oxoglutarate-dependent dioxygenases (2-ODDs) thus preventing inactivation. These enzymes have diverse functions and, recently, the possibility that ascorbate status in mammals could influence 2-ODDs involved in histone and DNA demethylation thereby influencing stem cell differentiation and cancer has been uncovered. Ascorbate is involved in iron uptake and transport in plants and animals. While the above biochemical functions are shared between mammals and plants, ascorbate peroxidase (APX) is an enzyme family limited to plants and photosynthetic protists. It provides these organisms with increased capacity to remove H2O2 produced by photosynthetic electron transport and photorespiration. The Fe reducing activity of ascorbate enables hydroxyl radical production (pro-oxidant effect) and the reactivity of dehydroascorbate (DHA) and reaction of its degradation products with proteins (dehydroascorbylation and glycation) is potentially damaging. Ascorbate status influences gene expression in plants and mammals but at present there is little evidence that it acts as a specific signalling molecule. It most likely acts indirectly by influencing the redox state of thiols and 2-ODD activity. However, the possibility that dehydroascorbylation is a regulatory post-translational protein modification could be explored.
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Affiliation(s)
- Nicholas Smirnoff
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK.
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