Efficient expression of a transgene in platelets using simian immunodeficiency virus-based vector harboring glycoprotein Ibα promoter: in vivo model for platelet-targeting gene therapy

• Published in: The FASEB journal 2006-07, Vol.20 (9), p.1522-1524
• Main Authors: Ohmori, Tsukasa, Mimuro, Jun, Takano, Katsuhiro, Madoiwa, Seiji, Kashiwakura, Yuji, Ishiwata, Akira, Niimura, Masanori, Mitomo, Katsuyuki, Tabata, Toshiaki, Hasegawa, Mamoru, Ozawa, Keiya, Sakata, Yoichi
• Format: Article
• Language: English
• Subjects: Cytomegalovirus; hemophilia A; lentiviral vector; Simian immunodeficiency virus; stem cell transplantation
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fj.05-5161fje

Platelets release several mediators that modify vascular integrity and hemostasis. In the present study, we developed a technique for efficient transgene expression in platelets in vivo and examined whether this targeted-gene-product delivery system using a platelet release reaction could be exploited for clinical applications. Analysis of luciferase reporter gene constructs driven by platelet-specific promoters (the GPIIb, GPIbα, and GPVI) revealed that the GPIbα promoter was the most potent in the megakaryoblastic cell line UT-7/TPO and human CD34⁺-derived megakaryocytes. Transduction of UT-7/TPO; CD34⁺-derived megakaryocytes; and c-Kit⁺, ScaI⁺, and Lineage⁻ (KSL) murine hematopoietic stem cells with a simian immunodeficiency virus (SIV)-based lentiviral vector carrying eGFP resulted in efficient, dose-dependent expression of eGFP, and the GPIbα promoter seemed to bestow megakaryocytic-specific expression. Transplantation of KSL cells transduced with SIV vector containing eGFP into mice showed that there was preferable expression of eGFP in platelets driven by the GPIbα promoter [7-11% for the cytomeglovirus (CMV) promoter, 16-27% for the GPIbα promoter]. Furthermore, transplantation of ex vivo-transduced KSL cells by SIV vector carrying human factorVIII (hFVIII) driven by the GPIbα promoter induced the production of detectable transcripts of the hFVIII gene and the hFVIII antigen in bone marrow and spleen for at least 90 days and partially corrected the hemophilia A phenotype. Platelet-targeting gene therapy using SIV vectors appears to be promising for gene therapy approaches toward not only inherited platelet diseases but also other hemorrhagic disorders such as hemophilia A.--Ohmori, T., Mimuro, J., Takano, K., Madoiwa, S., Kashiwakura, Y., Ishiwata, A., Niimura, M., Mitomo, K., Tabata, T., Hasegawa, M., Ozawa, K., Sakata, Y. Efficient expression of a transgene in platelets using simian immunodeficiency virus-based vector harboring glycoprotein Ibα promoter: in vivo model for platelet-targeting gene therapy.