Page 182 - 2019_07 resto del Mondo-web

Ferrata Storti Foundation
Haematologica 2019 Volume 104(7):1460-1472
Platelet Biology & its Disorders
Molecular mechanisms of bleeding disorder- associated GFI1BQ287* mutation and its affected pathways in megakaryocytes
and platelets
Rinske van Oorschot,1* Marten Hansen,2* Johanna M. Koornneef,3* Anna E. Marneth,1 Saskia M. Bergevoet,1 Maaike G.J.M. van Bergen,1 Floris P.J. van Alphen,4 Carmen van der Zwaan,3 Joost H.A. Martens,5 Michiel Vermeulen,5 Pascal W.T.C. Jansen,5 Marijke P.A. Baltissen,5 Britta A.P. Laros-van Gorkom,6 Hans Janssen,7 Joop H. Jansen,1 Marieke von Lindern,2 Alexander B. Meijer,3 Emile van den Akker2 and Bert A. van der Reijden1
1Department of Laboratory Medicine, Laboratory of Hematology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Nijmegen; 2Department of Hematopoiesis, Sanquin Research-Academic Medical Center Landsteiner Laboratory, Amsterdam; 3Department of Plasma Proteins, Sanquin Research, Amsterdam; 4Department of Research Facilities, Sanquin Research, Amsterdam; 5Department of Molecular Biology, Faculty of Science, Radboud University Nijmegen, Radboud Institute for Molecular Life Sciences, Nijmegen; 6Department of Hematology, Radboud University Medical Center, Nijmegen and 7Department of Biochemistry, the Netherlands Cancer Institute, Amsterdam, the Netherlands
*RO, MH, and JMK contributed equally to this work.
ABSTRACT
Dominant-negative mutations in the transcription factor Growth Factor Independence-1B (GFI1B), such as GFI1BQ287*, cause a bleed- ing disorder characterized by a plethora of megakaryocyte and platelet abnormalities. The deregulated molecular mechanisms and path- ways are unknown. Here we show that both normal and Q287* mutant GFI1B interacted most strongly with the lysine specific demethylase-1 – REST corepressor - histone deacetylase (LSD1-RCOR-HDAC) complex in megakaryoblasts. Sequestration of this complex by GFI1BQ287* and chemical separation of GFI1B from LSD1 induced abnormalities in normal megakary- ocytes comparable to those seen in patients. Megakaryocytes derived from GFI1BQ287*-induced pluripotent stem cells also phenocopied abnormalities seen in patients. Proteome studies on normal and mutant-induced pluripo- tent stem cell-derived megakaryocytes identified a multitude of deregulated pathways downstream of GFI1BQ287* including cell division and interferon signaling. Proteome studies on platelets from GFI1BQ287* patients showed reduced expression of proteins implicated in platelet function, and elevated expression of proteins normally downregulated during megakaryocyte dif- ferentiation. Thus, GFI1B and LSD1 regulate a broad developmental pro- gram during megakaryopoiesis, and GFI1BQ287* deregulates this program through LSD1-RCOR-HDAC sequestering.
Introduction
Platelets are specialized cell fragments that function to prevent excessive bleeding upon blood vessel injury.1 During megakaryopoiesis, megakaryoblasts undergo endomitosis followed by cytoplasmic maturation, during which a- and δ-granules are formed. Subsequently, mature megakaryocytes migrate to blood vessels in the bone marrow or lung, where they form protrusions and shed proplatelets into the bloodstream.2,3
The identification of inherited bleeding and platelet disorder mutations has pro- vided insight into proteins crucial for platelet production and function. Genes mutated in these disorders range from those encoding proteins involved in a-gran- ule biology, such as NBEAL2, to transcription factors controlling a wide range of
Correspondence:
BERT A. VAN DER REIJDEN
bert.vanderReijden@radboudumc.nl
Received: March 30, 2018. Accepted: January 9, 2019. Pre-published: January 17, 2019.
doi:10.3324/haematol.2018.194555
Check the online version for the most updated information on this article, online supplements, and information on authorship & disclosures: www.haematologica.org/content/104/7/1460
©2019 Ferrata Storti Foundation
Material published in Haematologica is covered by copyright. All rights are reserved to the Ferrata Storti Foundation. Use of published material is allowed under the following terms and conditions: https://creativecommons.org/licenses/by-nc/4.0/legalcode. Copies of published material are allowed for personal or inter- nal use. Sharing published material for non-commercial pur- poses is subject to the following conditions: https://creativecommons.org/licenses/by-nc/4.0/legalcode, sect. 3. Reproducing and sharing published material for com- mercial purposes is not allowed without permission in writing from the publisher.
1460
haematologica | 2019; 104(7)
ARTICLE