Direct Gene Transfer Into Human Epileptogenic Hippocampal Tissue with an Adeno-Associated Virus Vector: Implications for a Gene Therapy Approach to Epilepsy

Authors

  • Andrew Freese,

    Corresponding author
    1. Division of Neurosurgery, University of Pennsylvania School of Medicine, Philadelphia, U.S.A.
    2. Laboratory of Molecular Neurosurgery, Bockus Research Institute, Graduate Hospital, Philadelphia, U.S.A.
      Address correspondence and reprint requests to Dr. A. Freese at Division of Neurosurgery, University of Pennsylvania School of Medicine, 3400 Spruce St., Philadelphia, PA 19104–6380.
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  • Michael G. Kaplitt,

    1. Division of Neurosurgery, New York Hospital, Cornell University and Rockefeller University, New York, New York, U.S.A.
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  • William M. O'Connor,

    1. Laboratory of Molecular Neurosurgery, Bockus Research Institute, Graduate Hospital, Philadelphia, U.S.A.
    2. Department of Neurosurgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, U.S.A.
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  • Maureen Abbey,

    1. Laboratory of Molecular Neurosurgery, Bockus Research Institute, Graduate Hospital, Philadelphia, U.S.A.
    2. Department of Neurosurgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, U.S.A.
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  • David Langer,

    1. Division of Neurosurgery, University of Pennsylvania School of Medicine, Philadelphia, U.S.A.
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  • Paola Leone,

    1. Molecular Pharmacology and Neurogenetics Laboratory, Section of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut, U.S.A.
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  • Michael J. O'Connor,

    1. Division of Neurosurgery, University of Pennsylvania School of Medicine, Philadelphia, U.S.A.
    2. Laboratory of Molecular Neurosurgery, Bockus Research Institute, Graduate Hospital, Philadelphia, U.S.A.
    3. Department of Neurosurgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, U.S.A.
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  • Matthew J. During

    1. Molecular Pharmacology and Neurogenetics Laboratory, Section of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut, U.S.A.
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Address correspondence and reprint requests to Dr. A. Freese at Division of Neurosurgery, University of Pennsylvania School of Medicine, 3400 Spruce St., Philadelphia, PA 19104–6380.

Abstract

Summary: Purpose: Virus vectors capable of transferring genetic information into human cells provide hope for improved therapy in several neurological diseases, including epilepsy. We evaluated the ability of an adeno-associated virus (AAV) vector to transfer and cause expression of a lacZ marker gene in brain slices obtained from patients undergoing temporal lobectomy for control of medically intractable seizures.

Methods: Human brain slices were injected with an AAV vector (AAVlac Z) encoding Escherichia coliβ-galactosidase and incubated for as long as 24 h. The presence of lacZ mRNA. β-galactosidase protein and enzymatic activity were assayed by reverse transcriptase polymerase chain reaction (rtPCR), immunocytochemistry, and the X-Gal technique, respectively.

Results: AAVlac Z directed the expression in human epileptogenic brain of E. coliβ-galactosidase that had functional activity. Expression was observed in S5 h and was sustained for as long as the slices were viable. Morphological analysis indicated that neurons were preferentially transfected, and there was no evidence of cytotoxicity.

Conclusions: Our results confirm the feasibility of using AAV vectors to transfer genes into the human CNS and in particular, into neurons. Replacement of the lac Z gene with a functional gene modulating hippocampal neuronal physiology, might allow a localized genetic intervention for focal seizures based on the stereotaxic or endovascular delivery of such a vector system into the appropriate brain region.

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