Development of megakaryocyte-specific lentiviral vectors for gene therapy of platelet disorders

Liesbeth De Waele, Kathleen Freson, Chantal Thys, Christel Van Geet, D. Collen, Thierry VandenDriessche, Marinee Chuah

Research output: Contribution to journalEditorial


Introduction: For some life-threatening bleeding disorders such as GATA1 deficiency, the current therapies are insufficient, justifying the development of alternative strategies as gene therapy. The objective of the study is to develop improved lentiviral vectors for megakaryocyte(MK)-specific long term gene expression by ex vivo transduction of hematopoietic stem cells (HSC).

Methods: Self-inactivating lentiviral vectors were constructed expressing GFP driven by the murine (m) or human (h) GPIIb promoter. To evaluate the lineage-specificity and expression potential of the vectors, human and murine HSC were transduced in vitro and in vivo. The GPIIb promoter was also tested in GATA1 deficient HSC.

Results: We transduced murine and human HSC with Lenti-hGPIIb-GFP and Lenti-mGPIIb-GFP. After transduction the HSC were induced to differentiate in vitro along the MK and non-MK lineages. Both GPIIb promoters drove expression at higher levels (20%) than the ubiquitous CMV or PGK promoters, exclusively in the MK lineage. In both human and murine HSC the hGPIIb promoter with an extra RUNX1 and GATA1 binding site, was more potent in the MK lineage compared to the mGPIIb promoter. Since FLI1 and GATA1 are the main transcription factors regulating GPIIb expression, we tested the Lenti-hGPIIb-GFP construct in GATA1 deficient HSC and obtained comparable transduction efficiencies as for WT HSC.

To assess the MK-specificity of the lentiviral vectors in vivo, we transplanted irradiated C57Bl/6 mice with HSC transduced with Lenti-hGPIIb-GFP. Four months after transplantation we could detect 6% GFP positive platelets without a GFP signal in other lineages.

Conclusions: In vitro and in vivo MK-specific transgene expression driven by the hGPIIb and mGPIIb promoters could be obtained after ex vivo genetic engineering of HSC by improved lentiviral vectors. Studies are ongoing to study whether this approach can induce phenotypic correction of GATA1 deficient mice by transplantation of ex vivo Lenti-hGPIIb-GATA1 transduced HSC.
Original languageEnglish
JournalJ Thromb Haemost
Publication statusPublished - 2007


  • Gene Therapy
  • Platelet Disorders


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