title: HSP70 sequestration by free α-globin promotes ineffective erythropoiesis in β-thalassaemia.
abstract: β-Thalassaemia major (β-TM) is an inherited haemoglobinopathy caused by a quantitative defect in the synthesis of β-globin chains of haemoglobin, leading to the accumulation of free α-globin chains that form toxic aggregates. Despite extensive knowledge of the molecular defects causing β-TM, little is known of the mechanisms responsible for the ineffective erythropoiesis observed in the condition, which is characterized by accelerated erythroid differentiation, maturation arrest and apoptosis at the polychromatophilic stage. We have previously demonstrated that normal human erythroid maturation requires a transient activation of caspase-3 at the later stages of maturation. Although erythroid transcription factor GATA-1, the master transcriptional factor of erythropoiesis, is a caspase-3 target, it is not cleaved during erythroid differentiation. We have shown that, in human erythroblasts, the chaperone heat shock protein70 (HSP70) is constitutively expressed and, at later stages of maturation, translocates into the nucleus and protects GATA-1 from caspase-3 cleavage. The primary role of this ubiquitous chaperone is to participate in the refolding of proteins denatured by cytoplasmic stress, thus preventing their aggregation. Here we show in vitro that during the maturation of human β-TM erythroblasts, HSP70 interacts directly with free α-globin chains. As a consequence, HSP70 is sequestrated in the cytoplasm and GATA-1 is no longer protected, resulting in end-stage maturation arrest and apoptosis. Transduction of a nuclear-targeted HSP70 mutant or a caspase-3-uncleavable GATA-1 mutant restores terminal maturation of β-TM erythroblasts, which may provide a rationale for new targeted therapies of β-TM.
authors.affiliation: 1] Laboratoire INSERM, unité mixte de recherche 1163, centre national de la recherche scientifique (CNRS) équipe de recherche labellisée 8254, 24 Boulevard de Montparnasse, 75015 Paris, France [2] Service de Médecine Interne, Faculté de médecine Paris Descartes, Sorbonne Paris-Cité et Assistance publique - Hôpitaux de Paris, Hôpital Européen Georges Pompidou, 15 rue Leblanc 75908 Paris, France [3] Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Assistance publique - Hôpitaux de Paris, Hôpital Necker, 24 Boulevard de Montparnasse, 75015 Paris, France [4] Laboratory of Excellence GR-Ex, 75015 Paris, France [5].
authors.forename: Jean-Benoît
authors.initials: JB
authors.lastname: Arlet
authors.affiliation: 1] Laboratoire INSERM, unité mixte de recherche 1163, centre national de la recherche scientifique (CNRS) équipe de recherche labellisée 8254, 24 Boulevard de Montparnasse, 75015 Paris, France [2] Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Assistance publique - Hôpitaux de Paris, Hôpital Necker, 24 Boulevard de Montparnasse, 75015 Paris, France [3] Laboratory of Excellence GR-Ex, 75015 Paris, France [4] Département de Biothérapie, Faculté de médecine Paris Descartes, Sorbonne Paris-Cité et Assistance publique - Hôpitaux de Paris, Hôpital Necker, 149 rue de Sèvres 75015 Paris, France [5].
authors.forename: Jean-Antoine
authors.initials: JA
authors.lastname: Ribeil
authors.affiliation: 1] Laboratoire INSERM, unité mixte de recherche 1163, centre national de la recherche scientifique (CNRS) équipe de recherche labellisée 8254, 24 Boulevard de Montparnasse, 75015 Paris, France [2] Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Assistance publique - Hôpitaux de Paris, Hôpital Necker, 24 Boulevard de Montparnasse, 75015 Paris, France [3] Laboratory of Excellence GR-Ex, 75015 Paris, France.
authors.forename: Flavia
authors.initials: F
authors.lastname: Guillem
authors.affiliation: Commissariat à l'énergie atomique (CEA), Institute of Emerging Diseases and Innovative Therapies (iMETI), 18 Route du Panorama, 92260 Fontenay-aux-Roses, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Negre
authors.affiliation: 1] INSERM, unité mixte de recherche 866, Equipe labellisée Ligue contre le Cancer and Association pour la Recherche contre le Cancer, and Laboratoire d'Excellence Lipoprotéines et santé (LipSTIC), 21033 Dijon, France [2] University of Burgundy, Faculty of Medicine and Pharmacy, 7 boulevard Jeanne d'Arc, 21033 Dijon, France.
authors.forename: Adonis
authors.initials: A
authors.lastname: Hazoume
authors.affiliation: 1] INSERM, unité mixte de recherche 866, Equipe labellisée Ligue contre le Cancer and Association pour la Recherche contre le Cancer, and Laboratoire d'Excellence Lipoprotéines et santé (LipSTIC), 21033 Dijon, France [2] University of Burgundy, Faculty of Medicine and Pharmacy, 7 boulevard Jeanne d'Arc, 21033 Dijon, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Marcion
authors.affiliation: Commissariat à l'énergie atomique (CEA), Institute of Emerging Diseases and Innovative Therapies (iMETI), 18 Route du Panorama, 92260 Fontenay-aux-Roses, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Beuzard
authors.affiliation: 1] Laboratoire INSERM, unité mixte de recherche 1163, centre national de la recherche scientifique (CNRS) équipe de recherche labellisée 8254, 24 Boulevard de Montparnasse, 75015 Paris, France [2] Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Assistance publique - Hôpitaux de Paris, Hôpital Necker, 24 Boulevard de Montparnasse, 75015 Paris, France [3] Laboratory of Excellence GR-Ex, 75015 Paris, France [4] INSERM, unité mixte de recherche 699, Hôpital Bichat, 46 rue Henri Huchard, 75018 Paris, France.
authors.forename: Michaël
authors.initials: M
authors.lastname: Dussiot
authors.affiliation: 1] Laboratoire INSERM, unité mixte de recherche 1163, centre national de la recherche scientifique (CNRS) équipe de recherche labellisée 8254, 24 Boulevard de Montparnasse, 75015 Paris, France [2] Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Assistance publique - Hôpitaux de Paris, Hôpital Necker, 24 Boulevard de Montparnasse, 75015 Paris, France [3] Laboratory of Excellence GR-Ex, 75015 Paris, France [4] INSERM, unité mixte de recherche 699, Hôpital Bichat, 46 rue Henri Huchard, 75018 Paris, France [5] Faculté de médecine and Université Denis Diderot Paris VII, 5 Rue Thomas Mann, 75013 Paris, France.
authors.forename: Ivan Cruz
authors.initials: IC
authors.lastname: Moura
authors.affiliation: Centre national de la recherche scientifique (CNRS), unité mixte de recherche 8113, Ecole Normale Supérieure de Cachan, 61 avenue du président Wilson, 94230 Cachan, France.
authors.forename: Samuel
authors.initials: S
authors.lastname: Demarest
authors.affiliation: 1] Centre national de la recherche scientifique (CNRS), unité mixte de recherche 8113, Ecole Normale Supérieure de Cachan, 61 avenue du président Wilson, 94230 Cachan, France [2] Laboratoire d'Excellence en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Campus Paris Saclay, 5 rue Jean-Baptiste Clément 92296 Châtenay-Malabry, France.
authors.forename: Isaure Chauvot
authors.initials: IC
authors.lastname: de Beauchêne
authors.affiliation: 1] Laboratoire INSERM, unité mixte de recherche 1163, centre national de la recherche scientifique (CNRS) équipe de recherche labellisée 8254, 24 Boulevard de Montparnasse, 75015 Paris, France [2] Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Assistance publique - Hôpitaux de Paris, Hôpital Necker, 24 Boulevard de Montparnasse, 75015 Paris, France [3] Laboratory of Excellence GR-Ex, 75015 Paris, France.
authors.forename: Zakia
authors.initials: Z
authors.lastname: Belaid-Choucair
authors.affiliation: 1] INSERM, unité mixte de recherche 866, Equipe labellisée Ligue contre le Cancer and Association pour la Recherche contre le Cancer, and Laboratoire d'Excellence Lipoprotéines et santé (LipSTIC), 21033 Dijon, France [2] University of Burgundy, Faculty of Medicine and Pharmacy, 7 boulevard Jeanne d'Arc, 21033 Dijon, France.
authors.forename: Margaux
authors.initials: M
authors.lastname: Sevin
authors.affiliation: 1] Laboratoire INSERM, unité mixte de recherche 1163, centre national de la recherche scientifique (CNRS) équipe de recherche labellisée 8254, 24 Boulevard de Montparnasse, 75015 Paris, France [2] Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Assistance publique - Hôpitaux de Paris, Hôpital Necker, 24 Boulevard de Montparnasse, 75015 Paris, France [3] Laboratory of Excellence GR-Ex, 75015 Paris, France [4] INSERM, unité mixte de recherche 699, Hôpital Bichat, 46 rue Henri Huchard, 75018 Paris, France [5] Faculté de médecine and Université Denis Diderot Paris VII, 5 Rue Thomas Mann, 75013 Paris, France.
authors.forename: Thiago Trovati
authors.initials: TT
authors.lastname: Maciel
authors.affiliation: 1] Centre national de la recherche scientifique (CNRS), unité mixte de recherche 8113, Ecole Normale Supérieure de Cachan, 61 avenue du président Wilson, 94230 Cachan, France [2] Laboratoire d'Excellence en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Campus Paris Saclay, 5 rue Jean-Baptiste Clément 92296 Châtenay-Malabry, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Auclair
authors.affiliation: 1] Commissariat à l'énergie atomique (CEA), Institute of Emerging Diseases and Innovative Therapies (iMETI), 18 Route du Panorama, 92260 Fontenay-aux-Roses, France [2] Women's Hospital and Harvard Medical School, 25 Shattuck St, Boston, Massachusetts 02115, USA.
authors.forename: Philippe
authors.initials: P
authors.lastname: Leboulch
authors.affiliation: Commissariat à l'énergie atomique (CEA), Institute of Emerging Diseases and Innovative Therapies (iMETI), 18 Route du Panorama, 92260 Fontenay-aux-Roses, France.
authors.forename: Stany
authors.initials: S
authors.lastname: Chretien
authors.affiliation: 1] Centre national de la recherche scientifique (CNRS), unité mixte de recherche 8113, Ecole Normale Supérieure de Cachan, 61 avenue du président Wilson, 94230 Cachan, France [2] Laboratoire d'Excellence en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Campus Paris Saclay, 5 rue Jean-Baptiste Clément 92296 Châtenay-Malabry, France.
authors.forename: Luba
authors.initials: L
authors.lastname: Tchertanov
authors.affiliation: INSERM, unité mixte de recherche 779, Université Paris XI, Le Kremlin-Bicêtre, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Baudin-Creuza
authors.affiliation: University of Burgundy, Faculty of Medicine and Pharmacy, 7 boulevard Jeanne d'Arc, 21033 Dijon, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: Seigneuric
authors.affiliation: 1] Laboratory of Excellence GR-Ex, 75015 Paris, France [2] Institut Cochin, INSERM, unité mixte de recherche 1016, centre national de la recherche scientifique (CNRS), unité mixte de recherche 8104, Université Paris Descartes, and Assistance publique - Hôpitaux de Paris, Hôpitaux Universitaires Paris Centre, Hôpital Cochin, Service d'hématologie biologique, 27 rue du Faubourg Saitn-Jacques, 75014 Paris, France.
authors.forename: Michaela
authors.initials: M
authors.lastname: Fontenay
authors.affiliation: 1] INSERM, unité mixte de recherche 866, Equipe labellisée Ligue contre le Cancer and Association pour la Recherche contre le Cancer, and Laboratoire d'Excellence Lipoprotéines et santé (LipSTIC), 21033 Dijon, France [2] University of Burgundy, Faculty of Medicine and Pharmacy, 7 boulevard Jeanne d'Arc, 21033 Dijon, France [3] Centre anticancéreux George François Leclerc, 1 rue professeur Marion, 21079 Dijon, France [4].
authors.forename: Carmen
authors.initials: C
authors.lastname: Garrido
authors.affiliation: 1] Laboratoire INSERM, unité mixte de recherche 1163, centre national de la recherche scientifique (CNRS) équipe de recherche labellisée 8254, 24 Boulevard de Montparnasse, 75015 Paris, France [2] Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Assistance publique - Hôpitaux de Paris, Hôpital Necker, 24 Boulevard de Montparnasse, 75015 Paris, France [3] Laboratory of Excellence GR-Ex, 75015 Paris, France [4] Service d'hématologie, Faculté de médecine Paris Descartes, Sorbonne Paris-Cité et Assistance publique - Hôpitaux de Paris Hôpital Necker, 149 rue de Sèvres, 75015 Paris, France [5].
authors.forename: Olivier
authors.initials: O
authors.lastname: Hermine
authors.affiliation: 1] Laboratoire INSERM, unité mixte de recherche 1163, centre national de la recherche scientifique (CNRS) équipe de recherche labellisée 8254, 24 Boulevard de Montparnasse, 75015 Paris, France [2] Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Assistance publique - Hôpitaux de Paris, Hôpital Necker, 24 Boulevard de Montparnasse, 75015 Paris, France [3] Laboratory of Excellence GR-Ex, 75015 Paris, France [4].
authors.forename: Geneviève
authors.initials: G
authors.lastname: Courtois
mesh_terms: D017209:Apoptosis; D001853:Bone Marrow / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival / Q000235:genetics; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D004789:Enzyme Activation; D004900:Erythroblasts / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D004920:Erythropoiesis / Q000235:genetics; D050982:GATA1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D058990:Molecular Targeted Therapy; D011485:Protein Binding; D058849:Protein Refolding; D055542:alpha-Globins / Q000378:metabolism*; D017086:beta-Thalassemia / Q000097:blood* / Q000378:metabolism* / Q000473:pathology
chemical_list: D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; D018840:HSP70 Heat-Shock Proteins; D055542:alpha-Globins; D053148:Caspase 3