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CME Evaluation

Oral Communication Session

Platelet Disorders

Session: Inherited platelet disorders - Functional analysis

OC 55.5 - Impaired protein composition unveils alterations in platelet structure and functionality and contributes to hemorrhagic syndrome in ETV6-related thrombocytopenia

Tuesday, June 25, 2024
10:30 – 10:45 ICT
Room: 110 A-C

    Co-Author(s)

  • IT

    Ivan Tesakov

    Researcher
    Dmitry Rogachev National Medical Research Centеr of Pediatric Hematology, Oncology and Immunology
    Moscow, Moskva, Russia

    • Co-Author(s)

  • AM

    Alexey Martyanov

    Researcher
    Dmitry Rogachev National Medical Research Centеr of Pediatric Hematology, Oncology and Immunology
    Chapel Hill, North Carolina, United States

  • DF

    Darya Fedorova

    Hematologist
    Dmitry Rogachev National Medical Research Centеr of Pediatric Hematology, Oncology and Immunology
    Moscow, Moskva, Russia

  • Olga An, MD

    PhD Candidate
    University Medical Center Mainz, Center for Thrombosis and Hemostasis
    Mainz, Rheinland-Pfalz, Germany

    • Presenting Author(s)

  • Anna Boldova, PhD

    PhD student
    Center for Theoretical Problems of Physicochemical Pharmacology
    Moscow, Moskva, Russia

    • Co-Author(s)

  • AG

    Andrei Garzon

    Researcher
    Center for Theoretical Problems of Physico-Сhemical Pharmacology
    Moscow, Moskva, Russia

  • AI

    Anastasia Ignatova

    Research associate
    Dmitry Rogachev National Medical Research Centеr of Pediatric Hematology, Oncology and Immunology
    Moscow, Moskva, Russia

  • JK

    Julia-Jessica Korobkin

    Researcher
    Center for Theoretical Problems of Physico-Сhemical Pharmacology
    Moscow, Moskva, Russia

  • AP

    Anna Pavlova

    Molecular Genetics Diagnostic Laboratory
    Institute of Experimental Hematology and Transfusion Medicine, University Hospital Bonn
    Bonn, Nordrhein-Westfalen, Germany

  • EY

    Eugenia Yushkova

    Junior researcher
    Center for Theoretical Problems of Physico-Сhemical Pharmacology
    Moscow, Moskva, Russia

  • VZ

    Viktor Zgoda

    Head of the Department of Proteomic Research and Mass Spectrometry
    Institute of Biomedical Chemistry
    Moscow, Moskva, Russia

  • PZ

    Pavel Zharkov

    Doctor of Science, Head of Hemostasis Pathology Unit
    Dmitry Rogachev National Medical Research Center Of Pediatric Hematology, Oncology and Immunology
    Moscow, Moskva, Russia

  • MP

    Mikhail Panteleev

    Director
    Center for Theoretical Problems of Physico-Сhemical Pharmacology
    Moscow, Moskva, Russia

  • GN

    Galina A. Novichkova

    General director, MD
    Dmitry Rogachev National Research Center of Pediatric Hematology, Oncology and Immunology
    Moscow, Moskva, Russia

  • AS

    Anastasia N. Sveshnikova

    Head of Laboratory
    Dmitry Rogachev National Medical Research Center Of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
    Moscow, Moskva, Russia

Background: ETV6-related thrombocytopenia (ETV6-RT) is caused by germline mutations in the ETV6 gene, encoding the ETV6 transcription factor. While several targets of ETV6 have been reported, there is limited understanding of the impact of ETV6-RT on platelet structure and functioning.

Aims: Elucidation of the mechanisms of hemostatic dysfunction in ETV6-RT.

Methods: Nine patients (5 pediatric and 4 adults) from 5 families with ETV6-RT and ten pediatric healthy donors were enrolled in the study. Bleeding propensity was evaluated using ISTH/SSC bleeding assessment tool (ISTH-BAT). Platelet functionality was assessed by flow cytometry and ex vivo thrombi formation assay. Blood smears were examined using immunofluorescent microscopy. Proteomics analysis of purified platelets was performed in triplicates using Ultimate 3000 RSLC nano chromatographic HPLC system. Data were analyzed using MaxQuant software. The study was performed in accordance with the Declaration of Helsinki and approved by the independent ethics committee.

Results: The majority of patients presented with mild-to-moderate thrombocytopenia. Median ISTH-BAT scores were 3 (1 to 9) for pediatric patients, and 0 (0 to 1) for adults. The ability of platelets to form thrombi ex vivo was noticeably decreased. While platelet functional responses upon strong activation were comparable to controls, we observed diminished calcium mobilization and fibrinogen binding upon activation by ADP. Microscopic examination revealed platelet shape abnormalities and diffuse distribution of β1-tubulin. Among 976 proteins identified by platelet proteomics analysis, only 78 were unique for healthy controls, while 393 proteins were found exclusively in ETV6-RT. We identified three major groups of proteins (cytoskeleton proteins, proteins responsible for vesicle transport, and mitochondrial proteins) whose expression was significantly altered in ETV6-RT.

Conclusion(s): Alterations in the composition of cytoskeleton proteins contribute to impaired platelet structure and abnormal functional responses in ETV6-RT. The study was supported by the endowment foundation "Science for Children".