Germline variants in ETV6 underlie reduced platelet formation, platelet dysfunction and increased levels of circulating CD34+ progenitors
Marjorie Poggi,
Matthias Canault,
Marie Favier,
Ernest Turro,
Paul Saultier,
Dorsaf Ghalloussi,
Veronique Baccini,
Lea Vidal,
Anna Mezzapesa,
Nadjim Chelghoum,
Badreddine Mohand-Oumoussa,
Céline Falaise,
Rémi Favier,
Willem H. Ouwehand,
Mathieu Fiore,
Franck Peiretti,
Pierre Emmanuel Morange,
Noémie Saut,
Denis Bernot,
Andreas Greinacher,
NIHR BioResource,
Alan T. Nurden,
Paquita Nurden,
Kathleen Freson,
David-Alexandre Trégouët,
Hana Raslova,
Marie-Christine Alessi
Affiliations
Marjorie Poggi
Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France
Matthias Canault
Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France
Marie Favier
Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France;Inserm U1170, Gustave Roussy, University Paris Sud, Equipe labellisée Ligue contre le Cancer 94805 Villejuif, France
Ernest Turro
Department of Haematology and National Health Service Blood & Transplant, Cambridge University, UK;MRC Biostatistics Unit, Cambridge, UK
Paul Saultier
Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France
Dorsaf Ghalloussi
Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France
Veronique Baccini
Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France
Lea Vidal
Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France
Anna Mezzapesa
Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France
Nadjim Chelghoum
Post-Genomic Platform of Pitié-Salpêtrière (P3S), Pierre and Marie Curie University, F-75013 Paris, France
Badreddine Mohand-Oumoussa
Post-Genomic Platform of Pitié-Salpêtrière (P3S), Pierre and Marie Curie University, F-75013 Paris, France
Céline Falaise
French Reference-Center on Inherited Platelet Disorders, Marseille, France
Rémi Favier
Assistance Publique-Hôpitaux de Paris, Hôpital Armand Trousseau, Paris, France
Willem H. Ouwehand
Department of Haematology and National Health Service Blood & Transplant, Cambridge University, UK;Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
Mathieu Fiore
French Reference-Center on Inherited Platelet Disorders, Marseille, France;Laboratoire d’hématologie, CHU de Bordeaux, Pessac, France
Franck Peiretti
Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France
Pierre Emmanuel Morange
Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France;French Reference-Center on Inherited Platelet Disorders, Marseille, France
Noémie Saut
Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France;French Reference-Center on Inherited Platelet Disorders, Marseille, France
Denis Bernot
Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France
Andreas Greinacher
Institute for Immunology and Transfusion Medicine, University Medicine Greifswald, Germany
NIHR BioResource
NIHR BioResource - Rare Diseases, Cambridge University Hospitals, Cambridge Biomedical Campus, UK
Alan T. Nurden
LIRYC, Plateforme Technologique et d’Innovation Biomédicale, Hôpital Xavier Arnozan, Pessac, France
Paquita Nurden
French Reference-Center on Inherited Platelet Disorders, Marseille, France;LIRYC, Plateforme Technologique et d’Innovation Biomédicale, Hôpital Xavier Arnozan, Pessac, France
Kathleen Freson
Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Belgium
David-Alexandre Trégouët
ICAN Institute of Cardiometabolism and Nutrition, F-75013 Paris, France;Inserm, UMR_S 1166, Team Genomics and Pathophysiology of Cardiovascular Diseases, F-75013 Paris, France;Sorbonne Universités, Université Pierre et Marie Curie (UPMC Univ Paris 06), UMR_S 1166, F-75013 Paris, France
Hana Raslova
Inserm U1170, Gustave Roussy, University Paris Sud, Equipe labellisée Ligue contre le Cancer 94805 Villejuif, France
Marie-Christine Alessi
Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France;French Reference-Center on Inherited Platelet Disorders, Marseille, France
Variants in ETV6, which encodes a transcription repressor of the E26 transformation-specific family, have recently been reported to be responsible for inherited thrombocytopenia and hematologic malignancy. We sequenced the DNA from cases with unexplained dominant thrombocytopenia and identified six likely pathogenic variants in ETV6, of which five are novel. We observed low repressive activity of all tested ETV6 variants, and variants located in the E26 transformation-specific binding domain (encoding p.A377T, p.Y401N) led to reduced binding to corepressors. We also observed a large expansion of megakaryocyte colony-forming units derived from variant carriers and reduced proplatelet formation with abnormal cytoskeletal organization. The defect in proplatelet formation was also observed in control CD34+ cell-derived megakaryocytes transduced with lentiviral particles encoding mutant ETV6. Reduced expression levels of key regulators of the actin cytoskeleton CDC42 and RHOA were measured. Moreover, changes in the actin structures are typically accompanied by a rounder platelet shape with a highly heterogeneous size, decreased platelet arachidonic response, and spreading and retarded clot retraction in ETV6 deficient platelets. Elevated numbers of circulating CD34+ cells were found in p.P214L and p.Y401N carriers, and two patients from different families suffered from refractory anemia with excess blasts, while one patient from a third family was successfully treated for acute myeloid leukemia. Overall, our study provides novel insights into the role of ETV6 as a driver of cytoskeletal regulatory gene expression during platelet production, and the impact of variants resulting in platelets with altered size, shape and function and potentially also in changes in circulating progenitor levels.