title: Abnormal proplatelet formation and emperipolesis in cultured human megakaryocytes from gray platelet syndrome patients.
abstract: The Gray Platelet Syndrome (GPS) is a rare inherited bleeding disorder characterized by deficiency of platelet α-granules, macrothrombocytopenia and marrow fibrosis. The autosomal recessive form of GPS is linked to loss of function mutations in NBEAL2, which is predicted to regulate granule trafficking in megakaryocytes, the platelet progenitors. We report the first analysis of cultured megakaryocytes from GPS patients with NBEAL2 mutations. Megakaryocytes cultured from peripheral blood or bone marrow hematopoietic progenitor cells from four patients were used to investigate megakaryopoiesis, megakaryocyte morphology and platelet formation. In vitro differentiation of megakaryocytes was normal, whereas we observed deficiency of megakaryocyte α-granule proteins and emperipolesis. Importantly, we first demonstrated that platelet formation by GPS megakaryocytes was severely affected, a defect which might be the major cause of thrombocytopenia in patients. These results demonstrate that cultured megakaryocytes from GPS patients provide a valuable model to understand the pathogenesis of GPS in humans.
authors.affiliation: Department of Molecular Medicine, University of Pavia, Pavia, Italy.|Biotechnology Research Laboratories, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Policlinico San Matteo Foundation, Pavia, Italy.
authors.forename: Christian A
authors.initials: CA
authors.lastname: Di Buduo
authors.affiliation: Department of Internal Medicine, Policlinico Agostino Gemelli, Catholic University, Rome, Italy.
authors.forename: Maria Adele
authors.initials: MA
authors.lastname: Alberelli
authors.affiliation: Hematology Research, Instituto de Investigaciones Médicas Alfredo Lanari, University of Buenos Aires, CONICET, Buenos Aires, Argentina.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Glembostky
authors.affiliation: Medicina III, Azienda Ospedaliera San Paolo, Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy.
authors.forename: Gianmarco
authors.initials: G
authors.lastname: Podda
authors.affiliation: Hematology Research, Instituto de Investigaciones Médicas Alfredo Lanari, University of Buenos Aires, CONICET, Buenos Aires, Argentina.
authors.forename: Paola R
authors.initials: PR
authors.lastname: Lev
authors.affiliation: Medicina III, Azienda Ospedaliera San Paolo, Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Cattaneo
authors.affiliation: Department of Internal Medicine, Policlinico Agostino Gemelli, Catholic University, Rome, Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Landolfi
authors.affiliation: Hematology Research, Instituto de Investigaciones Médicas Alfredo Lanari, University of Buenos Aires, CONICET, Buenos Aires, Argentina.
authors.forename: Paula G
authors.initials: PG
authors.lastname: Heller
authors.affiliation: Department of Molecular Medicine, University of Pavia, Pavia, Italy.|Biotechnology Research Laboratories, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Policlinico San Matteo Foundation, Pavia, Italy.|Department of Biomedical Engineering, Tufts University, Medford, MA, USA.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Balduini
authors.affiliation: Department of Internal Medicine, Policlinico Agostino Gemelli, Catholic University, Rome, Italy.
authors.forename: Erica
authors.initials: E
authors.lastname: De Candia
mesh_terms: D000368:Aged; D001792:Blood Platelets / Q000166:cytology* / Q000378:metabolism; D001798:Blood Proteins / Q000235:genetics*; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D002648:Child; D057687:Emperipolesis; D055652:Gray Platelet Syndrome / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008297:Male; D008533:Megakaryocytes / Q000166:cytology* / Q000378:metabolism / Q000473:pathology; D008954:Models, Biological; D009154:Mutation; D055815:Young Adult
chemical_list: D001798:Blood Proteins; C561485:NBEAL2 protein, human; D002118:Calcium