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Kuo KH. Pyruvate kinase activators: targeting red cell metabolism in thalassemia. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2023; 2023:114-120. [PMID: 38066911 PMCID: PMC10727068 DOI: 10.1182/hematology.2023000468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Thalassemia is an inherited red blood cell disorder whereby the qualitative and/or quantitative imbalance in α- to β-globin ratio results in hemolysis and ineffective erythropoiesis. Oxidative stress, from the precipitated excess globin and free iron, is a major factor that drives hemolysis and ineffective erythropoiesis. Pyruvate kinase activity and adenosine triphosphate availability are reduced due to the overwhelmed cellular antioxidant system from the excessive oxidative stress. Mitapivat, a pyruvate kinase activator in development as a treatment for thalassemia, was shown to increase hemoglobin and reduce hemolysis in a small phase 2 single-arm trial of patients with α- and β-thalassemia. The ongoing phase 3 studies with mitapivat and the phase 2 study with etavopivat will examine the role of pyruvate kinase activators as disease modifying agents in thalassemia.
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Affiliation(s)
- Kevin H.M. Kuo
- Division of Hematology, Department of Medicine, University of Toronto, Toronto, Canada
- Division of Medical Oncology and Hematology, Department of Medicine, University Health Network, Toronto, ON, Canada
- Institute of Health Policy, Management and Evaluation, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
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Reboucas P, Fillebeen C, Botta A, Cleverdon R, Steele AP, Richard V, Zahedi RP, Borchers CH, Burelle Y, Hawke TJ, Pantopoulos K, Sweeney G. Discovery-Based Proteomics Identify Skeletal Muscle Mitochondrial Alterations as an Early Metabolic Defect in a Mouse Model of β-Thalassemia. Int J Mol Sci 2023; 24:ijms24054402. [PMID: 36901833 PMCID: PMC10002226 DOI: 10.3390/ijms24054402] [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: 01/17/2023] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 02/25/2023] Open
Abstract
Although metabolic complications are common in thalassemia patients, there is still an unmet need to better understand underlying mechanisms. We used unbiased global proteomics to reveal molecular differences between the th3/+ mouse model of thalassemia and wild-type control animals focusing on skeletal muscles at 8 weeks of age. Our data point toward a significantly impaired mitochondrial oxidative phosphorylation. Furthermore, we observed a shift from oxidative fibre types toward more glycolytic fibre types in these animals, which was further supported by larger fibre-type cross-sectional areas in the more oxidative type fibres (type I/type IIa/type IIax hybrid). We also observed an increase in capillary density in th3/+ mice, indicative of a compensatory response. Western blotting for mitochondrial oxidative phosphorylation complex proteins and PCR analysis of mitochondrial genes indicated reduced mitochondrial content in the skeletal muscle but not the hearts of th3/+ mice. The phenotypic manifestation of these alterations was a small but significant reduction in glucose handling capacity. Overall, this study identified many important alterations in the proteome of th3/+ mice, amongst which mitochondrial defects leading to skeletal muscle remodelling and metabolic dysfunction were paramount.
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Affiliation(s)
| | - Carine Fillebeen
- Lady Davis Institute for Medical Research, Department of Medicine, McGill University, Montreal, QC H3T 1E2, Canada
| | - Amy Botta
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada
| | - Riley Cleverdon
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Alexandra P. Steele
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Vincent Richard
- Lady Davis Institute for Medical Research, Department of Medicine, McGill University, Montreal, QC H3T 1E2, Canada
- Segal Cancer Proteomics Centre, Lady Davis Institute, Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University, Montreal, QC H3T 1E2, Canada
| | - René P. Zahedi
- Lady Davis Institute for Medical Research, Department of Medicine, McGill University, Montreal, QC H3T 1E2, Canada
- Segal Cancer Proteomics Centre, Lady Davis Institute, Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University, Montreal, QC H3T 1E2, Canada
- Manitoba Centre for Proteomics & Systems Biology, University of Manitoba, Winnipeg, MB R3E 3P4, Canada
- Department of Internal Medicine, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Christoph H. Borchers
- Lady Davis Institute for Medical Research, Department of Medicine, McGill University, Montreal, QC H3T 1E2, Canada
- Segal Cancer Proteomics Centre, Lady Davis Institute, Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University, Montreal, QC H3T 1E2, Canada
- Manitoba Centre for Proteomics & Systems Biology, University of Manitoba, Winnipeg, MB R3E 3P4, Canada
| | - Yan Burelle
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Thomas J. Hawke
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Kostas Pantopoulos
- Lady Davis Institute for Medical Research, Department of Medicine, McGill University, Montreal, QC H3T 1E2, Canada
| | - Gary Sweeney
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada
- Correspondence: ; Tel.: +1-416-736-2100 (ext. 66635)
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Biochemistry of mammalian ferritins in the regulation of cellular iron homeostasis and oxidative responses. SCIENCE CHINA. LIFE SCIENCES 2020; 64:352-362. [PMID: 32974854 DOI: 10.1007/s11427-020-1795-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/11/2020] [Indexed: 02/08/2023]
Abstract
Ferritin, an iron-storage protein, regulates cellular iron metabolism and oxidative stress. The ferritin structure is characterized as a spherical cage, inside which large amounts of iron are deposited in a safe, compact and bioavailable form. All ferritins readily catalyze Fe(II) oxidation by peroxides at the ferroxidase center to prevent free Fe(II) from participating in oxygen free radical formation via Fenton chemistry. Thus, ferritin is generally recognized as a cytoprotective stratagem against intracellular oxidative damage The expression of cytosolic ferritins is usually regulated by iron status and oxidative stress at both the transcriptional and post-transcriptional levels. The mechanism of ferritin-mediated iron recycling is far from clarified, though nuclear receptor co-activator 4 (NCOA4) was recently identified as a cargo receptor for ferritin-based lysosomal degradation. Cytosolic ferritins are heteropolymers assembled by H- and L-chains in different proportions. The mitochondrial ferritins are homopolymers and distributed in restricted tissues. They play protective roles in mitochondria where heme- and Fe/S-enzymes are synthesized and high levels of ROS are produced. Genetic ferritin disorders are mainly related to the L-chain mutations, which generally cause severe movement diseases. This review is focused on the biochemistry and function of mammalian intracellular ferritin as the major iron-storage and anti-oxidation protein.
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