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Cheng IH, Pi WC, Hsu CH, Guo Y, Lai JL, Wang GG, Chung BC, Roeder RG, Chen WY. TAF2, within the TFIID complex, regulates the expression of a subset of protein-coding genes. Cell Death Discov 2024; 10:244. [PMID: 38773077 PMCID: PMC11109217 DOI: 10.1038/s41420-024-02017-z] [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: 01/23/2024] [Revised: 05/03/2024] [Accepted: 05/08/2024] [Indexed: 05/23/2024] Open
Abstract
TFIID, one of the general transcription factor (GTF), regulates transcriptional initiation of protein-coding genes through direct binding to promoter elements and subsequent recruitment of other GTFs and RNA polymerase II. Although generally required for most protein-coding genes, accumulated studies have also demonstrated promoter-specific functions for several TFIID subunits in gene activation. Here, we report that TBP-associated factor 2 (TAF2) specifically regulates TFIID binding to a small subset of protein-coding genes and is essential for cell growth of multiple cancer lines. Co-immunoprecipitation assays revealed that TAF2 may be sub-stoichiometrically associated with the TFIID complex, thus indicating a minor fraction of TAF2-containing TFIID in cells. Consistently, integrated genome-wide profiles show that TAF2 binds to and regulates only a small subset of protein-coding genes. Furthermore, through the use of an inducible TAF2 degradation system, our results reveal a reduction of TBP/TFIID binding to several ribosomal genes upon selective ablation of TAF2. In addition, depletion of TAF2, as well as the TAF2-regulated ribosomal protein genes RPL30 and RPL39, decreases ribosome assembly and global protein translation. Collectively, this study suggests that TAF2 within the TFIID complex is of functional importance for TBP/TFIID binding to and expression of a small subset of protein-coding genes, thus establishing a previously unappreciated promoter-selective function for TAF2.
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Affiliation(s)
- I-Hsin Cheng
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Wen-Chieh Pi
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chung-Hao Hsu
- School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yiran Guo
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, 27710, USA
- Duke Cancer Institute, Durham, NC, 27710, USA
| | - Jun-Lin Lai
- Program in Molecular Medicine, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan
| | - Gang G Wang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, 27710, USA
- Duke Cancer Institute, Durham, NC, 27710, USA
| | - Bon-Chu Chung
- Insitute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- Graduate Institute of Biomedical Sciences, Neuroscience and Brain Disease Center, China Medical University, Taichung, Taiwan
- National Laboratory Animal Center, National Applied Research Laboratories, Taipei, Taiwan
| | - Robert G Roeder
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY, 10065, USA
| | - Wei-Yi Chen
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, Taiwan.
- Program in Molecular Medicine, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan.
- Cancer and Immunology Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan.
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2
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Duncan BB, Lotter JL, Superata J, Barranta ME, Machado T, Darden I, Venugopal S, Wu CO, Abkowitz JL, Dunbar CE, Young DJ. Treatment of refractory/relapsed Diamond-Blackfan anaemia with eltrombopag. Br J Haematol 2024; 204:2077-2085. [PMID: 38462764 PMCID: PMC11212774 DOI: 10.1111/bjh.19357] [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: 12/03/2023] [Accepted: 02/13/2024] [Indexed: 03/12/2024]
Abstract
Diamond-Blackfan anaemia (DBA) is a rare, inherited bone marrow failure syndrome with a ribosomal defect causing slowed globin chain production with normal haem synthesis, causing an overabundance of reactive iron/haem and erythroid-specific cellular toxicity. Eltrombopag, a non-peptide thrombopoietin receptor agonist, is a potent intracellular iron chelator and induced a robust durable response in an RPS19-mutated DBA patient on another trial. We hypothesized eltrombopag would improve RBC production in DBA patients. We conducted a single-centre, single-arm pilot study (NCT04269889) assessing safety and erythroid response of 6 months of daily, fixed-dose eltrombopag for DBA patients. Fifteen transfusion-dependent (every 3-5 weeks) patients (median age 18 [range 2-56]) were treated. One responder had sustained haemoglobin improvement and >50% reduction in RBC transfusion frequency. Of note, 7/15 (41%) patients required dose reductions or sustained discontinuation of eltrombopag due to asymptomatic thrombocytosis. Despite the low response rate, eltrombopag has now improved erythropoiesis in several patients with DBA with a favourable safety profile. Dosing restrictions due to thrombocytosis may cause insufficient iron chelation to decrease haem production and improve anaemia in most patients. Future work will focus on erythropoiesis dynamics in patients and use of haem synthesis inhibitors without an impact on other haematopoietic lineages.
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Affiliation(s)
- Brynn B Duncan
- Translational Stem Cell Biology Branch, NHLBI, Bethesda, Maryland, USA
| | | | | | | | - Tania Machado
- Office of the Clinical Director, NHLBI, Bethesda, Maryland, USA
| | - Ivana Darden
- Office of the Clinical Director, NHLBI, Bethesda, Maryland, USA
| | | | - Colin O Wu
- Office of Biostatistics Research, NHLBI, Bethesda, Maryland, USA
| | - Janis L Abkowitz
- Division of Hematology, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Cynthia E Dunbar
- Translational Stem Cell Biology Branch, NHLBI, Bethesda, Maryland, USA
| | - David J Young
- Translational Stem Cell Biology Branch, NHLBI, Bethesda, Maryland, USA
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3
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Gonzalez-Menendez P, Phadke I, Olive ME, Joly A, Papoin J, Yan H, Galtier J, Platon J, Kang SWS, McGraw KL, Daumur M, Pouzolles M, Kondo T, Boireau S, Paul F, Young DJ, Lamure S, Mirmira RG, Narla A, Cartron G, Dunbar CE, Boyer-Clavel M, Porat-Shliom N, Dardalhon V, Zimmermann VS, Sitbon M, Dever TE, Mohandas N, Da Costa L, Udeshi ND, Blanc L, Kinet S, Taylor N. Arginine metabolism regulates human erythroid differentiation through hypusination of eIF5A. Blood 2023; 141:2520-2536. [PMID: 36735910 PMCID: PMC10273172 DOI: 10.1182/blood.2022017584] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 01/20/2023] [Accepted: 01/20/2023] [Indexed: 02/05/2023] Open
Abstract
Metabolic programs contribute to hematopoietic stem and progenitor cell (HSPC) fate, but it is not known whether the metabolic regulation of protein synthesis controls HSPC differentiation. Here, we show that SLC7A1/cationic amino acid transporter 1-dependent arginine uptake and its catabolism to the polyamine spermidine control human erythroid specification of HSPCs via the activation of the eukaryotic translation initiation factor 5A (eIF5A). eIF5A activity is dependent on its hypusination, a posttranslational modification resulting from the conjugation of the aminobutyl moiety of spermidine to lysine. Notably, attenuation of hypusine synthesis in erythroid progenitors, by the inhibition of deoxyhypusine synthase, abrogates erythropoiesis but not myeloid cell differentiation. Proteomic profiling reveals mitochondrial translation to be a critical target of hypusinated eIF5A, and accordingly, progenitors with decreased hypusine activity exhibit diminished oxidative phosphorylation. This affected pathway is critical for eIF5A-regulated erythropoiesis, as interventions augmenting mitochondrial function partially rescue human erythropoiesis under conditions of attenuated hypusination. Levels of mitochondrial ribosomal proteins (RPs) were especially sensitive to the loss of hypusine, and we find that the ineffective erythropoiesis linked to haploinsufficiency of RPS14 in chromosome 5q deletions in myelodysplastic syndrome is associated with a diminished pool of hypusinated eIF5A. Moreover, patients with RPL11-haploinsufficient Diamond-Blackfan anemia as well as CD34+ progenitors with downregulated RPL11 exhibit a markedly decreased hypusination in erythroid progenitors, concomitant with a loss of mitochondrial metabolism. Thus, eIF5A-dependent protein synthesis regulates human erythropoiesis, and our data reveal a novel role for RPs in controlling eIF5A hypusination in HSPCs, synchronizing mitochondrial metabolism with erythroid differentiation.
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Affiliation(s)
- Pedro Gonzalez-Menendez
- Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Montpellier, France
- Laboratory of Excellence GR-Ex, Paris, France
| | - Ira Phadke
- Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Montpellier, France
- Laboratory of Excellence GR-Ex, Paris, France
- Pediatric Oncology Branch, National Cancer Institute (NCI), Center for Cancer Research (CCR), National Institutes of Health (NIH), Bethesda, MD
| | - Meagan E. Olive
- Proteomics Platform, Broad Institute, Massachusetts Institute of Technology and Harvard University, Cambridge, MA
| | - Axel Joly
- Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Montpellier, France
- Laboratory of Excellence GR-Ex, Paris, France
| | - Julien Papoin
- Feinstein Institute for Medical Research, Manhasset, NY
- EA4666 HEMATIM, Université Picardie Jules Verne, Amiens, France
| | | | - Jérémy Galtier
- Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Montpellier, France
- Laboratory of Excellence GR-Ex, Paris, France
| | - Jessica Platon
- EA4666 HEMATIM, Université Picardie Jules Verne, Amiens, France
| | | | - Kathy L. McGraw
- Laboratory of Receptor Biology and Gene Expression, NCI, CCR, NIH, Bethesda, MD
| | - Marie Daumur
- Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Montpellier, France
- Laboratory of Excellence GR-Ex, Paris, France
| | - Marie Pouzolles
- Pediatric Oncology Branch, National Cancer Institute (NCI), Center for Cancer Research (CCR), National Institutes of Health (NIH), Bethesda, MD
| | - Taisuke Kondo
- Pediatric Oncology Branch, National Cancer Institute (NCI), Center for Cancer Research (CCR), National Institutes of Health (NIH), Bethesda, MD
| | - Stéphanie Boireau
- Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Montpellier, France
- Montpellier Ressources Imagerie, BioCampus, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Franciane Paul
- Department of Clinical Hematology, Centre Hospitalier Universitaire de Montpellier, Montpellier, France
| | - David J. Young
- Translational Stem Cell Biology Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD
| | - Sylvain Lamure
- Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Montpellier, France
- Department of Clinical Hematology, Centre Hospitalier Universitaire de Montpellier, Montpellier, France
| | | | - Anupama Narla
- Division of Pediatric Hematology/Oncology, Stanford University, Stanford, CA
| | - Guillaume Cartron
- Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Montpellier, France
- Department of Clinical Hematology, Centre Hospitalier Universitaire de Montpellier, Montpellier, France
| | - Cynthia E. Dunbar
- Translational Stem Cell Biology Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD
| | - Myriam Boyer-Clavel
- Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Montpellier, France
| | | | - Valérie Dardalhon
- Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Montpellier, France
| | - Valérie S. Zimmermann
- Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Montpellier, France
| | - Marc Sitbon
- Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Montpellier, France
- Laboratory of Excellence GR-Ex, Paris, France
| | - Thomas E. Dever
- Section on Protein Biosynthesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD
| | | | - Lydie Da Costa
- Laboratory of Excellence GR-Ex, Paris, France
- EA4666 HEMATIM, Université Picardie Jules Verne, Amiens, France
- Service d'Hématologie Biologique (Hematology Diagnostic Laboratory), Assistance Publique–Hôpitaux de Paris, Robert Debr Hôpital, Paris, France
- Paris Cité University, Paris, France
| | - Namrata D. Udeshi
- Proteomics Platform, Broad Institute, Massachusetts Institute of Technology and Harvard University, Cambridge, MA
| | - Lionel Blanc
- Feinstein Institute for Medical Research, Manhasset, NY
| | - Sandrina Kinet
- Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Montpellier, France
- Laboratory of Excellence GR-Ex, Paris, France
| | - Naomi Taylor
- Institut de Génétique Moléculaire de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Montpellier, France
- Laboratory of Excellence GR-Ex, Paris, France
- Pediatric Oncology Branch, National Cancer Institute (NCI), Center for Cancer Research (CCR), National Institutes of Health (NIH), Bethesda, MD
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4
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Outcome of colorectal cancer in Diamond-Blackfan syndrome with a ribosomal protein S19 mutation. Clin J Gastroenterol 2020; 13:1173-1177. [PMID: 32643123 DOI: 10.1007/s12328-020-01176-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 06/22/2020] [Indexed: 10/23/2022]
Abstract
Diamond-Blackfan anemia is an autosomal dominant syndrome, characterized by anemia and a predisposition for malignancies. Ribosomal proteins are responsible for this syndrome, and the incidence of colorectal cancer in patients with this syndrome is higher than the general population. This patient's Diamond-Blackfan anemia was caused by a novel ribosomal protein S19 gene mutation, and he received chemotherapy for colorectal cancer caused by it. In his cancer, ribosomal proteins S19 and TP53 were overexpressed. He received 5FU and cetuximab; however, his anemia made chemotherapy difficult, and he did not survive long. Patients with Diamond-Blackfan anemia should be screened earlier and more often for colorectal cancer than usual.
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5
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Turi Z, Lacey M, Mistrik M, Moudry P. Impaired ribosome biogenesis: mechanisms and relevance to cancer and aging. Aging (Albany NY) 2019; 11:2512-2540. [PMID: 31026227 PMCID: PMC6520011 DOI: 10.18632/aging.101922] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 04/04/2019] [Indexed: 02/06/2023]
Abstract
The biosynthesis of ribosomes is a complex process that requires the coordinated action of many factors and a huge energy investment from the cell. Ribosomes are essential for protein production, and thus for cellular survival, growth and proliferation. Ribosome biogenesis is initiated in the nucleolus and includes: the synthesis and processing of ribosomal RNAs, assembly of ribosomal proteins, transport to the cytoplasm and association of ribosomal subunits. The disruption of ribosome biogenesis at various steps, with either increased or decreased expression of different ribosomal components, can promote cell cycle arrest, senescence or apoptosis. Additionally, interference with ribosomal biogenesis is often associated with cancer, aging and age-related degenerative diseases. Here, we review current knowledge on impaired ribosome biogenesis, discuss the main factors involved in stress responses under such circumstances and focus on examples with clinical relevance.
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Affiliation(s)
- Zsofia Turi
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 779 00 Olomouc, Czech Republic
| | - Matthew Lacey
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 779 00 Olomouc, Czech Republic
| | - Martin Mistrik
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 779 00 Olomouc, Czech Republic
| | - Pavel Moudry
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 779 00 Olomouc, Czech Republic
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6
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Regulation of globin-heme balance in Diamond-Blackfan anemia by HSP70/GATA1. Blood 2019; 133:1358-1370. [PMID: 30700418 DOI: 10.1182/blood-2018-09-875674] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 01/12/2019] [Indexed: 02/07/2023] Open
Abstract
Diamond-Blackfan anemia (DBA) is a congenital erythroblastopenia that is characterized by a blockade in erythroid differentiation related to impaired ribosome biogenesis. DBA phenotype and genotype are highly heterogeneous. We have previously identified 2 in vitro erythroid cell growth phenotypes for primary CD34+ cells from DBA patients and following short hairpin RNA knockdown of RPS19, RPL5, and RPL11 expression in normal human CD34+ cells. The haploinsufficient RPS19 in vitro phenotype is less severe than that of 2 other ribosomal protein (RP) mutant genes. We further documented that proteasomal degradation of HSP70, the chaperone of GATA1, is a major contributor to the defect in erythroid proliferation, delayed erythroid differentiation, increased apoptosis, and decreased globin expression, which are all features of the RPL5 or RPL11 DBA phenotype. In the present study, we explored the hypothesis that an imbalance between globin and heme synthesis may be involved in pure red cell aplasia of DBA. We identified disequilibrium between the globin chain and the heme synthesis in erythroid cells of DBA patients. This imbalance led to accumulation of excess free heme and increased reactive oxygen species production that was more pronounced in cells of the RPL5 or RPL11 phenotype. Strikingly, rescue experiments with wild-type HSP70 restored GATA1 expression levels, increased globin synthesis thereby reducing free heme excess and resulting in decreased apoptosis of DBA erythroid cells. These results demonstrate the involvement of heme in DBA pathophysiology and a major role of HSP70 in the control of balanced heme/globin synthesis.
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7
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Oyarbide U, Topczewski J, Corey SJ. Peering through zebrafish to understand inherited bone marrow failure syndromes. Haematologica 2018; 104:13-24. [PMID: 30573510 PMCID: PMC6312012 DOI: 10.3324/haematol.2018.196105] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 11/14/2018] [Indexed: 12/22/2022] Open
Abstract
Inherited bone marrow failure syndromes are experiments of nature characterized by impaired hematopoiesis with cancer and leukemia predisposition. The mutations associated with inherited bone marrow failure syndromes affect fundamental cellular pathways, such as DNA repair, telomere maintenance, or proteostasis. How these disturbed pathways fail to produce sufficient blood cells and lead to leukemogenesis are not understood. The rarity of inherited cytopenias, the paucity of affected primary human hematopoietic cells, and the sometime inadequacy of murine or induced pluripotential stem cell models mean it is difficult to acquire a greater understanding of them. Zebrafish offer a model organism to study gene functions. As vertebrates, zebrafish share with humans many orthologous genes involved in blood disorders. As a model organism, zebrafish provide advantages that include rapid development of transparent embryos, high fecundity (providing large numbers of mutant and normal siblings), and a large collection of mutant and transgenic lines useful for investigating the blood system and other tissues during development. Importantly, recent advances in genomic editing in zebrafish can speedily validate the new genes or novel variants discovered in clinical investigation as causes for marrow failure. Here we review zebrafish as a model organism that phenocopies Fanconi anemia, Diamond-Blackfan anemia, dyskeratosis congenita, Shwachman-Diamond syndrome, congenital amegakaryocytic thrombocytopenia, and severe congenital neutropenia. Two important insights, provided by modeling inherited cytopenias in zebrafish, widen understanding of ribosome biogenesis and TP53 in mediating marrow failure and non-hematologic defects. They suggest that TP53-independent pathways contribute to marrow failure. In addition, zebrafish provide an attractive model organism for drug development.
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Affiliation(s)
- Usua Oyarbide
- Department of Pediatrics, Children's Hospital of Richmond and Massey Cancer Center at Virginia Commonwealth University, Richmond, VA, USA
| | - Jacek Topczewski
- Department of Pediatrics, Stanley Manne Children's Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.,Department of Biochemistry and Molecular Biology, Medical University of Lublin, Poland
| | - Seth J Corey
- Department of Pediatrics, Children's Hospital of Richmond and Massey Cancer Center at Virginia Commonwealth University, Richmond, VA, USA .,Department of Microbiology/Immunology, Virginia Commonwealth University, USA.,Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, USA
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8
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Perreault AA, Benton ML, Koury MJ, Brandt SJ, Venters BJ. Epo reprograms the epigenome of erythroid cells. Exp Hematol 2017; 51:47-62. [PMID: 28410882 DOI: 10.1016/j.exphem.2017.03.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 03/28/2017] [Accepted: 03/31/2017] [Indexed: 12/25/2022]
Abstract
The hormone erythropoietin (Epo) is required for erythropoiesis, yet its molecular mechanism of action remains poorly understood, particularly with respect to chromatin dynamics. To investigate how Epo modulates the erythroid epigenome, we performed epigenetic profiling using an ex vivo murine cell system that undergoes synchronous erythroid maturation in response to Epo stimulation. Our findings define the repertoire of Epo-modulated enhancers, illuminating a new facet of Epo signaling. First, a large number of enhancers rapidly responded to Epo stimulation, revealing a cis-regulatory network of Epo-responsive enhancers. In contrast, most of the other identified enhancers remained in an active acetylated state during Epo signaling, suggesting that most erythroid enhancers are established at an earlier precursor stage. Second, we identified several hundred super-enhancers that were linked to key erythroid genes, such as Tal1, Bcl11a, and Mir144/451. Third, experimental and computational validation revealed that many predicted enhancer regions were occupied by TAL1 and enriched with DNA-binding motifs for GATA1, KLF1, TAL1/E-box, and STAT5. Additionally, many of these cis-regulatory regions were conserved evolutionarily and displayed correlated enhancer:promoter acetylation. Together, these findings define a cis-regulatory enhancer network for Epo signaling during erythropoiesis, and provide the framework for future studies involving the interplay of epigenetics and Epo signaling.
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Affiliation(s)
- Andrea A Perreault
- Department of Molecular Physiology and Biophysics, Chemical and Physical Biology Program, Vanderbilt Genetics Institute, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, TN
| | - Mary Lauren Benton
- Department of Biomedical Informatics, Vanderbilt University, Nashville, TN
| | - Mark J Koury
- Division of Hematology/Oncology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Stephen J Brandt
- Department of Cancer Biology, Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
| | - Bryan J Venters
- Department of Molecular Physiology and Biophysics, Chemical and Physical Biology Program, Vanderbilt Genetics Institute, Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, TN.
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9
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Doty RT, Phelps SR, Shadle C, Sanchez-Bonilla M, Keel SB, Abkowitz JL. Coordinate expression of heme and globin is essential for effective erythropoiesis. J Clin Invest 2015; 125:4681-91. [PMID: 26551679 DOI: 10.1172/jci83054] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 10/08/2015] [Indexed: 01/27/2023] Open
Abstract
Erythropoiesis requires rapid and extensive hemoglobin production. Heme activates globin transcription and translation; therefore, heme synthesis must precede globin synthesis. As free heme is a potent inducer of oxidative damage, its levels within cellular compartments require stringent regulation. Mice lacking the heme exporter FLVCR1 have a severe macrocytic anemia; however, the mechanisms that underlie erythropoiesis dysfunction in these animals are unclear. Here, we determined that erythropoiesis failure occurs in these animals at the CFU-E/proerythroblast stage, a point at which the transferrin receptor (CD71) is upregulated, iron is imported, and heme is synthesized--before ample globin is produced. From the CFU-E/proerythroblast (CD71(+) Ter119(-) cells) stage onward, erythroid progenitors exhibited excess heme content, increased cytoplasmic ROS, and increased apoptosis. Reducing heme synthesis in FLVCR1-defient animals via genetic and biochemical approaches improved the anemia, implying that heme excess causes, and is not just associated with, the erythroid marrow failure. Expression of the cell surface FLVCR1 isoform, but not the mitochondrial FLVCR1 isoform, restored normal rbc production, demonstrating that cellular heme export is essential. Together, these studies provide insight into how heme is regulated to allow effective erythropoiesis, show that erythropoiesis fails when heme is excessive, and emphasize the importance of evaluating Ter119(-) erythroid cells when studying erythroid marrow failure in murine models.
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10
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Mercurio S, Aspesi A, Silengo L, Altruda F, Dianzani I, Chiabrando D. Alteration of heme metabolism in a cellular model of Diamond-Blackfan anemia. Eur J Haematol 2015; 96:367-74. [PMID: 26058344 DOI: 10.1111/ejh.12599] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2015] [Indexed: 01/23/2023]
Abstract
Diamond-Blackfan anemia (DBA) is a congenital pure red cell aplasia often associated with skeletal malformations. Mutations in ribosomal protein coding genes, mainly in RPS19, account for the majority of DBA cases. The molecular mechanisms underlying DBA pathogenesis are still not completely understood. Alternative spliced isoforms of FLVCR1 (feline leukemia virus subgroup C receptor 1) transcript coding for non-functional proteins have been reported in some DBA patients. Consistently, a phenotype very close to DBA has been described in animal models of FLVCR1 deficiency. FLVCR1 gene codes for two proteins: the plasma membrane heme exporter FLVCR1a and the mitochondrial heme exporter FLVCR1b. The coordinated expression of both FLVCR1 isoforms regulates an intracellular heme pool, necessary for proper expansion and differentiation of erythroid precursors. Here, we investigate the role of FLVCR1 isoforms in a cellular model of DBA. RPS19-downregulated TF1 cells show reduced FLVCR1a and FLVCR1b mRNA levels associated with heme overload. The downregulation of FLVCR1 isoforms affects cell cycle progression and apoptosis in differentiating K562 cells, a phenotype similar to DBA. Taken together, these data suggest that alteration of heme metabolism could play a role in the pathogenesis of DBA.
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Affiliation(s)
- Sonia Mercurio
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | - Anna Aspesi
- Department of Health Sciences, University of Eastern Piedmont, Novara, Italy
| | - Lorenzo Silengo
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | - Fiorella Altruda
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | - Irma Dianzani
- Department of Health Sciences, University of Eastern Piedmont, Novara, Italy
| | - Deborah Chiabrando
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy
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Chiabrando D, Vinchi F, Fiorito V, Mercurio S, Tolosano E. Heme in pathophysiology: a matter of scavenging, metabolism and trafficking across cell membranes. Front Pharmacol 2014; 5:61. [PMID: 24782769 PMCID: PMC3986552 DOI: 10.3389/fphar.2014.00061] [Citation(s) in RCA: 275] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 03/18/2014] [Indexed: 01/19/2023] Open
Abstract
Heme (iron-protoporphyrin IX) is an essential co-factor involved in multiple biological processes: oxygen transport and storage, electron transfer, drug and steroid metabolism, signal transduction, and micro RNA processing. However, excess free-heme is highly toxic due to its ability to promote oxidative stress and lipid peroxidation, thus leading to membrane injury and, ultimately, apoptosis. Thus, heme metabolism needs to be finely regulated. Intracellular heme amount is controlled at multiple levels: synthesis, utilization by hemoproteins, degradation and both intracellular and intercellular trafficking. This review focuses on recent findings highlighting the importance of controlling intracellular heme levels to counteract heme-induced oxidative stress. The contributions of heme scavenging from the extracellular environment, heme synthesis and incorporation into hemoproteins, heme catabolism and heme transport in maintaining adequate intracellular heme content are discussed. Particular attention is put on the recently described mechanisms of heme trafficking through the plasma membrane mediated by specific heme importers and exporters. Finally, the involvement of genes orchestrating heme metabolism in several pathological conditions is illustrated and new therapeutic approaches aimed at controlling heme metabolism are discussed.
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Affiliation(s)
- Deborah Chiabrando
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin Turin, Italy
| | - Francesca Vinchi
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin Turin, Italy
| | - Veronica Fiorito
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin Turin, Italy
| | - Sonia Mercurio
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin Turin, Italy
| | - Emanuela Tolosano
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin Turin, Italy
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Khan AA, Quigley JG. Heme and FLVCR-related transporter families SLC48 and SLC49. Mol Aspects Med 2013; 34:669-82. [PMID: 23506900 DOI: 10.1016/j.mam.2012.07.013] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 03/14/2012] [Indexed: 12/11/2022]
Abstract
Heme is critical for a variety of cellular processes, but excess intracellular heme may result in oxidative stress and membrane injury. Feline leukemia virus subgroup C receptor (FLVCR1), a member of the SLC49 family of four paralogous genes, is a cell surface heme exporter, essential for erythropoiesis and systemic iron homeostasis. Disruption of FLVCR1 function blocks development of erythroid progenitors, likely due to heme toxicity. Mutations of SLC49A1 encoding FLVCR1 are noted in patients with a rare neurodegenerative disorder: posterior column ataxia with retinitis pigmentosa. FLVCR2 is highly homologous to FLVCR1 and may function as a cellular heme importer. Mutations of SLC49A2 encoding FLVCR2 are observed in Fowler syndrome, a rare proliferative vascular disorder of the brain. The functions of the remaining members of the SLC49 family, MFSD7 and DIRC2 (encoded by the SLC49A3 and SLC49A4 genes), are unknown, although the latter is implicated in hereditary renal carcinomas. SLC48A1 (heme responsive gene-1, HRG-1), the sole member of the SLC48 family, is associated with the endosome and appears to transport heme from the endosome into the cytosol.
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Affiliation(s)
- Anwar A Khan
- Department of Medicine, Section of Hematology/Oncology, University of Illinois at Chicago, Chicago, IL, USA.
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Hannan KM, Sanij E, Rothblum LI, Hannan RD, Pearson RB. Dysregulation of RNA polymerase I transcription during disease. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:342-60. [PMID: 23153826 DOI: 10.1016/j.bbagrm.2012.10.014] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 10/30/2012] [Accepted: 10/31/2012] [Indexed: 12/13/2022]
Abstract
Transcription of the ribosomal RNA genes by the dedicated RNA polymerase I enzyme and subsequent processing of the ribosomal RNA are fundamental control steps in the synthesis of functional ribosomes. Dysregulation of Pol I transcription and ribosome biogenesis is linked to the etiology of a broad range of human diseases. Diseases caused by loss of function mutations in the molecular constituents of the ribosome, or factors intimately associated with RNA polymerase I transcription and processing are collectively termed ribosomopathies. Ribosomopathies are generally rare and treatment options are extremely limited tending to be more palliative than curative. Other more common diseases are associated with profound changes in cellular growth such as cardiac hypertrophy, atrophy or cancer. In contrast to ribosomopathies, altered RNA polymerase I transcriptional activity in these diseases largely results from dysregulated upstream oncogenic pathways or by direct modulation by oncogenes or tumor suppressors at the level of the RNA polymerase I transcription apparatus itself. Ribosomopathies associated with mutations in ribosomal proteins and ribosomal RNA processing or assembly factors have been covered by recent excellent reviews. In contrast, here we review our current knowledge of human diseases specifically associated with dysregulation of RNA polymerase I transcription and its associated regulatory apparatus, including some cases where this dysregulation is directly causative in disease. We will also provide insight into and discussion of possible therapeutic approaches to treat patients with dysregulated RNA polymerase I transcription. This article is part of a Special Issue entitled: Transcription by Odd Pols.
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Affiliation(s)
- K M Hannan
- Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, Locked Bag 1, A'Beckett St, Melbourne, Victoria 8006, Australia
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Hamza I, Dailey HA. One ring to rule them all: trafficking of heme and heme synthesis intermediates in the metazoans. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:1617-32. [PMID: 22575458 DOI: 10.1016/j.bbamcr.2012.04.009] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 04/15/2012] [Accepted: 04/19/2012] [Indexed: 12/17/2022]
Abstract
The appearance of heme, an organic ring surrounding an iron atom, in evolution forever changed the efficiency with which organisms were able to generate energy, utilize gasses and catalyze numerous reactions. Because of this, heme has become a near ubiquitous compound among living organisms. In this review we have attempted to assess the current state of heme synthesis and trafficking with a goal of identifying crucial missing information, and propose hypotheses related to trafficking that may generate discussion and research. The possibilities of spatially organized supramolecular enzyme complexes and organelle structures that facilitate efficient heme synthesis and subsequent trafficking are discussed and evaluated. Recently identified players in heme transport and trafficking are reviewed and placed in an organismal context. Additionally, older, well established data are reexamined in light of more recent studies on cellular organization and data available from newer model organisms. This article is part of a Special Issue entitled: Cell Biology of Metals.
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Affiliation(s)
- Iqbal Hamza
- Department of Animal & Avian Sciences, University of Maryland, College Park, MD 20742, USA.
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Mutations of FLVCR1 in posterior column ataxia and retinitis pigmentosa result in the loss of heme export activity. Blood Cells Mol Dis 2012; 49:60-6. [PMID: 22483575 DOI: 10.1016/j.bcmd.2012.03.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 02/28/2012] [Indexed: 11/20/2022]
Abstract
The feline leukemia virus subgroup C receptor 1 (FLVCR1) is a heme exporter that maintains the intracellular heme concentration. FLVCR1 was previously assumed to be involved in Diamond-Blackfan anemia, and it was recently reported that mutations in the FLVCR1 gene are found in patients with posterior column ataxia and retinitis pigmentosa (PCARP). Four mutations in FLVCR1 (Asn121Asp, Cys192Arg, Ala241Thr, and Gly493Arg) are located within putative transmembrane domains; however, the effects of FLVCR1 mutations on PCARP are unclear. In this study, we analyzed the function of FLVCR1 mutants by using a fluorescent heme analog as a transporter substrate, and found that all 4 FLVCR1 mutants lost their heme export activity. To investigate the mechanism responsible for this loss of activity, we determined the subcellular localization of FLVCR1 mutants. FLVCR1 mutants did not localize to the plasma membrane and were observed in intracellular structures, including lysosomes. We hypothesize that the loss of function of FLVCR1 mutants is caused by their mislocation. We examined the half-life of FLVCR1 in cells, which was >16h for wild-type FLVCR1 compared with 2-4h for the mutants. Based on these results, we propose that FLVCR1 mutants failed to fold properly in the ER, were rapidly degraded in the lysosomes, and therefore, could not export heme out of cells. Thus, accumulation of heme in FLVCR1-mutant cells could cause cellular toxicity.
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Pham CD, Yu Z, Ben Lovely C, Agarwal C, Myers DA, Paul JA, Cooper M, Barati M, Perlin MH. Haplo-insufficiency for different genes differentially reduces pathogenicity and virulence in a fungal phytopathogen. Fungal Genet Biol 2012; 49:21-9. [DOI: 10.1016/j.fgb.2011.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 11/16/2011] [Accepted: 11/17/2011] [Indexed: 11/26/2022]
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Abstract
Diamond Blackfan anemia (DBA) is a rare congenital anemia, with more than 50% of patients having mutations in a ribosomal protein. Evidence suggests that both translation and p53 activation play roles in mediating the hematopoietic phenotype. The reason for erythroid specificity of DBA is unclear. Several zebrafish models of DBA have been generated, and these models have already provided key information about disease pathogenesis. The zebrafish model is particularly amenable for studying blood development, allows for advanced imaging techniques, can be manipulated genetically, and is useful for high-throughput screening. By applying zebrafish approaches to the existing DBA models, we will be able to better understand the role of the ribosomal protein mutation in DBA and develop better treatments for this disease.
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Affiliation(s)
- Alison M Taylor
- Stem Cell Program and Division of Hematology/Oncology, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA
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Jaacks LM, Young MF, Essley BV, McNanley TJ, Cooper EM, Pressman EK, McIntyre AW, Orlando MS, Abkowitz JL, Guillet R, O'Brien KO. Placental expression of the heme transporter, feline leukemia virus subgroup C receptor, is related to maternal iron status in pregnant adolescents. J Nutr 2011; 141:1267-72. [PMID: 21593354 PMCID: PMC3738384 DOI: 10.3945/jn.110.135798] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Little is known about the expression of heme transporters in human placenta and possible associations between these transporters and maternal or neonatal iron status. To address this area of research, relative protein expression of 2 heme transporters, Feline Leukemia Virus, Subgroup C, Receptor 1 (FLVCR1) and Breast Cancer Resistance Protein (BCRP), was assessed using Western-blot analysis in human placental tissue in relation to maternal/neonatal iron status and placental iron concentration. Placental FLVCR1 (n = 71) and BCRP (n = 83) expression were assessed at term (36.6-41.7 wk gestation) in a cohort of pregnant adolescents (13-18 y of age) at high-risk of iron deficiency. Both FLVCR1 and BCRP were detected in all placental samples assayed. Placental FLVCR1 expression was positively related to placental BCRP expression (n = 69; R(2) = 0.104; P < 0.05). Adolescents that were anemic at delivery had lower placental FLVCR1 expression (n = 49; P < 0.05). Placental FLVCR1 expression was positively associated with placental iron concentration at delivery (n = 61; R(2) = 0.064; P < 0.05). In contrast, placental BCRP expression was not significantly associated with maternal iron status or placental iron content. Both FLVCR1 and BCRP are highly expressed in human placental tissue, but only FLVCR1 was significantly inversely associated with maternal iron status and placental iron concentration. Further analysis is needed to explore potential functional roles of FLVCR1 in human placental iron transport.
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Affiliation(s)
- Lindsay M. Jaacks
- Cornell University, Division of Nutritional Sciences, Ithaca, NY 14853-0001
| | - Melissa F. Young
- Cornell University, Division of Nutritional Sciences, Ithaca, NY 14853-0001
| | - Bridget V. Essley
- Cornell University, Division of Nutritional Sciences, Ithaca, NY 14853-0001
| | - Thomas J. McNanley
- The University of Rochester School of Medicine and Dentistry, Rochester, NY 14642-0001
| | - Elizabeth M. Cooper
- The University of Rochester School of Medicine and Dentistry, Rochester, NY 14642-0001
| | - Eva K. Pressman
- The University of Rochester School of Medicine and Dentistry, Rochester, NY 14642-0001
| | - Allison W. McIntyre
- The University of Rochester School of Medicine and Dentistry, Rochester, NY 14642-0001
| | - Mark S. Orlando
- The University of Rochester School of Medicine and Dentistry, Rochester, NY 14642-0001
| | - Janis L. Abkowitz
- University of Washington, Department of Medicine/Hematology, Seattle, WA 98195-7710
| | - Ronnie Guillet
- The University of Rochester School of Medicine and Dentistry, Rochester, NY 14642-0001
| | - Kimberly O. O'Brien
- Cornell University, Division of Nutritional Sciences, Ithaca, NY 14853-0001,To whom correspondence should be addressed. E-mail:
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Khan AA, Quigley JG. Control of intracellular heme levels: heme transporters and heme oxygenases. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1813:668-82. [PMID: 21238504 PMCID: PMC3079059 DOI: 10.1016/j.bbamcr.2011.01.008] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2010] [Revised: 12/31/2010] [Accepted: 01/06/2011] [Indexed: 12/19/2022]
Abstract
Heme serves as a co-factor in proteins involved in fundamental biological processes including oxidative metabolism, oxygen storage and transport, signal transduction and drug metabolism. In addition, heme is important for systemic iron homeostasis in mammals. Heme has important regulatory roles in cell biology, yet excessive levels of intracellular heme are toxic; thus, mechanisms have evolved to control the acquisition, synthesis, catabolism and expulsion of cellular heme. Recently, a number of transporters of heme and heme synthesis intermediates have been described. Here we review aspects of heme metabolism and discuss our current understanding of heme transporters, with emphasis on the function of the cell-surface heme exporter, FLVCR. Knockdown of Flvcr in mice leads to both defective erythropoiesis and disturbed systemic iron homeostasis, underscoring the critical role of heme transporters in mammalian physiology. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.
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Affiliation(s)
- Anwar A. Khan
- Department of Medicine, Section of Hematology/Oncology, University of Illinois College of Medicine, 909 South Wolcott Avenue, Chicago, IL-60612
| | - John G. Quigley
- Department of Medicine, Section of Hematology/Oncology, University of Illinois College of Medicine, 909 South Wolcott Avenue, Chicago, IL-60612
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Crosstalk between Erythropoiesis and Iron Metabolism. Adv Hematol 2010; 2010. [PMID: 20862206 PMCID: PMC2938435 DOI: 10.1155/2010/317095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 07/14/2010] [Indexed: 01/13/2023] Open
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