Sphingolipid dysregulation due to lack of functional KDSR impairs proplatelet formation causing thrombocytopenia
Tadbir K. Bariana,
Veerle Labarque,
Jessica Heremans,
Chantal Thys,
Mara De Reys,
Daniel Greene,
Benjamin Jenkins,
Luigi Grassi,
Denis Seyres,
Frances Burden,
Deborah Whitehorn,
Olga Shamardina,
Sofia Papadia,
Keith Gomez,
NIHR BioResource,
Chris Van Geet,
Albert Koulman,
Willem H. Ouwehand,
Cedric Ghevaert,
Mattia Frontini,
Ernest Turro,
Kathleen Freson
Affiliations
Tadbir K. Bariana
Department of Haematology, University College London, UK;The Katharine Dormandy Haemophilia Centre and Thrombosis Unit, Royal Free London NHS Foundation Trust, UK;Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK;NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK
Veerle Labarque
Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Belgium
Jessica Heremans
Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Belgium
Chantal Thys
NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK;Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Belgium
Mara De Reys
Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Belgium
Daniel Greene
Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK;NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK;NHS Blood and Transplant, Cambridge Biomedical Campus, UK;Medical Research Council Biostatistics Unit, Cambridge Institute of Public Health, Cambridge Biomedical Campus, UK
Benjamin Jenkins
NIHR Biomedical Research Centre Core Metabolomics and Lipidomics Laboratory, University of Cambridge, Cambridge Biomedical Campus, UK
Luigi Grassi
Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK;NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK;NHS Blood and Transplant, Cambridge Biomedical Campus, UK;Medical Research Council Biostatistics Unit, Cambridge Institute of Public Health, Cambridge Biomedical Campus, UK
Denis Seyres
Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK;NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK;NHS Blood and Transplant, Cambridge Biomedical Campus, UK;Medical Research Council Biostatistics Unit, Cambridge Institute of Public Health, Cambridge Biomedical Campus, UK
Frances Burden
Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK;NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK;NHS Blood and Transplant, Cambridge Biomedical Campus, UK
Deborah Whitehorn
Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK;NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK;NHS Blood and Transplant, Cambridge Biomedical Campus, UK
Olga Shamardina
Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK;NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK;NHS Blood and Transplant, Cambridge Biomedical Campus, UK
Sofia Papadia
Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK;NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK;NHS Blood and Transplant, Cambridge Biomedical Campus, UK
Keith Gomez
Department of Haematology, University College London, UK;The Katharine Dormandy Haemophilia Centre and Thrombosis Unit, Royal Free London NHS Foundation Trust, UK;NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK
NIHR BioResource
NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK
Chris Van Geet
NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK;Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Belgium
Albert Koulman
NIHR Biomedical Research Centre Core Metabolomics and Lipidomics Laboratory, University of Cambridge, Cambridge Biomedical Campus, UK
Willem H. Ouwehand
Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK;NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK;NHS Blood and Transplant, Cambridge Biomedical Campus, UK;British Heart Foundation Centre of Excellence, Division of Cardiovascular Medicine, Cambridge University Hospitals, Cambridge Biomedical Campus, UK;Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
Cedric Ghevaert
Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK;NHS Blood and Transplant, Cambridge Biomedical Campus, UK;British Heart Foundation Centre of Excellence, Division of Cardiovascular Medicine, Cambridge University Hospitals, Cambridge Biomedical Campus, UK
Mattia Frontini
Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK;NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK;NHS Blood and Transplant, Cambridge Biomedical Campus, UK;British Heart Foundation Centre of Excellence, Division of Cardiovascular Medicine, Cambridge University Hospitals, Cambridge Biomedical Campus, UK
Ernest Turro
Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, UK;NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK;NHS Blood and Transplant, Cambridge Biomedical Campus, UK;Medical Research Council Biostatistics Unit, Cambridge Institute of Public Health, Cambridge Biomedical Campus, UK
Kathleen Freson
NIHR BioResource, Cambridge University Hospitals, Cambridge Biomedical Campus, UK;Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, University of Leuven, Belgium
Sphingolipids are fundamental to membrane trafficking, apoptosis, and cell differentiation and proliferation. KDSR or 3-keto-dihydrosphingosine reductase is an essential enzyme for de novo sphingolipid synthesis, and pathogenic mutations in KDSR result in the severe skin disorder erythrokeratodermia variabilis et progressiva-4. Four of the eight reported cases also had thrombocytopenia but the underlying mechanism has remained unexplored. Here we expand upon the phenotypic spectrum of KDSR deficiency with studies in two siblings with novel compound heterozygous variants associated with thrombocytopenia, anemia, and minimal skin involvement. We report a novel phenotype of progressive juvenile myelofibrosis in the propositus, with spontaneous recovery of anemia and thrombocytopenia in the first decade of life. Examination of bone marrow biopsies showed megakaryocyte hyperproliferation and dysplasia. Megakaryocytes obtained by culture of CD34+ stem cells confirmed hyperproliferation and showed reduced proplatelet formation. The effect of KDSR insufficiency on the sphingolipid profile was unknown, and was explored in vivo and in vitro by a broad metabolomics screen that indicated activation of an in vivo compensatory pathway that leads to normalization of downstream metabolites such as ceramide. Differentiation of propositus-derived induced pluripotent stem cells to megakaryocytes followed by expression of functional KDSR showed correction of the aberrant cellular and biochemical phenotypes, corroborating the critical role of KDSR in proplatelet formation. Finally, Kdsr depletion in zebrafish recapitulated the thrombocytopenia and showed biochemical changes similar to those observed in the affected siblings. These studies support an important role for sphingolipids as regulators of cytoskeletal organization during megakaryopoiesis and proplatelet formation.
