Gene delivery to the spinal cord: Comparison between lentiviral, adenoviral, and retroviral vector delivery systems

Authors

  • Ahmed A. Abdellatif,

    1. Department of Anatomical Sciences and Neurobiology, University of Louisville, School of Medicine, Louisville, Kentucky
    2. Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, Kentucky
    3. Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville
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  • Jennifer L. Pelt,

    1. Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, Kentucky
    2. Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville
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  • Richard L. Benton,

    1. Department of Anatomical Sciences and Neurobiology, University of Louisville, School of Medicine, Louisville, Kentucky
    2. Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, Kentucky
    3. Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville
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  • Russell M. Howard,

    1. Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, Kentucky
    2. Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville
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  • Pantelis Tsoulfas,

    1. The Miami Project and Department of Neurological Surgery, University of Miami, School of Medicine, Miami, Florida
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  • Peipei Ping,

    1. Department of Medicine, University of Louisville, School of Medicine, Louisville, Kentucky
    Current affiliation:
    1. Departments of Physiology and Medicine, UCLA, School of Medicine, Los Angeles, California
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  • Xiao-Ming Xu,

    1. Department of Anatomical Sciences and Neurobiology, University of Louisville, School of Medicine, Louisville, Kentucky
    2. Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, Kentucky
    3. Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville
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  • Scott R. Whittemore

    Corresponding author
    1. Department of Anatomical Sciences and Neurobiology, University of Louisville, School of Medicine, Louisville, Kentucky
    2. Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville
    • Kentucky Spinal Cord Injury Research Center, Department of Neurological Surgery, University of Louisville, 511 South Floyd St., MDR 616, Louisville, KY 40202
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Abstract

Viral gene delivery for spinal cord injury (SCI) is a promising approach for enhancing axonal regeneration and neuroprotection. An understanding of spatio-temporal transgene expression in the spinal cord is essential for future studies of SCI therapies. Commonly, intracellular marker proteins (e.g., EGFP) were used as indicators of transgene levels after viral delivery, which may not accurately reflect levels of secreted transgene. This study examined transgene expression using ELISA after viral delivery of D15A, a neurotrophin with BDNF and NT-3 activities, at 1, 2, and 4weeks after in vivo and ex vivo delivery using lentiviral, adenoviral, and retroviral vectors. Further, the inflammatory responses and viral infection patterns after in vivo delivery were examined. Lentiviral vectors had the most stable pattern of gene expression, with D15A levels of 536 ± 38 and 363 ± 47 pg/mg protein seen at 4 weeks after the in vivo and ex vivo delivery, respectively. Our results show that protein levels downregulate disproportionately to levels of EGFP after adenoviral vectors both in vivo and ex vivo. D15A dropped from initial levels of 422 ± 87 to 153 ± 18 pg/mg protein at 4 weeks after in vivo administration. Similarly, ex vivo retrovirus-mediated transgene expression exhibited rapid downregulation by 2 weeks post-grafting. Compared to adenoviral infection, macrophage activation was attenuated after lentiviral infection. These results suggest that lentiviral vectors are most suitable in situations where stable long-term transgene expression is needed. Retroviral ex vivo delivery is optional when transient expression within targeted spinal tissue is desired, with adenoviral vectors in between. © 2006 Wiley-Liss, Inc.

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