, Volume 6, Issue 2, pp 307–311 | Cite as

Adeno-associated virus vector-mediated expression and constitutive secretion of galanin suppresses limbic seizure activity

Theme 3: Gene Therapy


Theoretically, gene therapy techniques offer an attractive alternative treatment option for intractable, focal epilepsies. Although logical gene therapy targets include excitatory and inhibitory receptors, variable viral vector tropism interjects an uncertainty as to the direction of change, seizure suppression, or seizure sensitization. To circumvent this therapeutic liability, adeno-associated virus (AAV) vectors have been constructed where the gene product is constitutively secreted from the transduced cell. Using AAV vectors, the fibronectin secretory signal sequence (FIB) was placed in front of the coding sequence for green fluorescent protein or the active portion of the neuroactive peptide galanin (GAL). Subsequent studies showed that these vectors supported expression and constitutive secretion of these gene products from transfected cells in vitro. More importantly, upon transduction in vivo, AAV-FIB-GAL vectors significantly attenuated focal seizure sensitivity, and this seizure attenuation could be controlled in vivo by using a tetracyclineregulated promoter. The expression and constitutive secretion of green fluorescent protein, or the expression of GAL alone, exerted no effect on focal seizure sensitivity. Moreover, unilateral infusion of the AAV-FIB-GAL vectors into the hippocampus prevented kainic acid-induced hilar cell death. With regard to limbic seizures, bilateral infusion of AAV-FIB-GAL vectors into the piriform cortex prevented both behavioral and localized electrographic seizure activity after the peripheral administration of kainic acid. Also, when rats were electrically kindled to class V seizure activity, subsequent infusion of AAV-FIB-GAL proved capable of significantly elevating the seizure initiation threshold. Thus, these studies clearly demonstrate the anti-seizure effectiveness of AAV vector-mediated expression and constitutive secretion of galanin.

Key Words

Epilepsy seizure galanin gene therapy adeno-associated virus 


  1. 1.
    Hauser WA, Hesdorffer DC. Epilepsy: frequency, causes and consequences. Hauser WA, Hesdorffer DC, Eds. Demos Publications, New York: 1990.Google Scholar
  2. 2.
    Kwan P, Brodie MJ. Early identification of refractory epilepsy. N Engl J Med 2000;342: 314–319.CrossRefPubMedGoogle Scholar
  3. 3.
    Ojemann GA. Treatment of temporal lobe epilepsy. Ann Rev Med 1997;48: 317–328.CrossRefPubMedGoogle Scholar
  4. 4.
    McCown TJ, Xiao X, Li J, Breese GR, Samulski RJ. Differential and persistent expression patterns of CNS gene transfer by an adeno-associated virus (AAV) vector. Brain Res 1996;713: 99–107.CrossRefPubMedGoogle Scholar
  5. 5.
    Naldini L, Blomer U, Gage FH, Trono D, Verma IM. Efficient transfer, integration and sustained long-term expression of the transgene in adult rat brains injected with a lentiviral vector. Proc Nat Acad Sci 1996;93: 11382–11388.CrossRefPubMedGoogle Scholar
  6. 6.
    Rogawski MA, Löscher W. The neurobiology of antiepileptic drugs. Nat Rev Neurosci 2004;7: 553–564.CrossRefGoogle Scholar
  7. 7.
    Monyer H, Sprengel R, Schoepfer R, et al. Heteromeric NMDA receptors: molecular and functional distinction of subtypes. Science 1992;256: 1217–1221.CrossRefPubMedGoogle Scholar
  8. 8.
    Hollmann M, Heinmann S. Cloned glutamate receptors. Ann Rev Neurosci 1994;17: 31–108.CrossRefPubMedGoogle Scholar
  9. 9.
    Haberman RP, Criswell HE, Snowdy S, et al. Therapeutic liabilities of in vivo viral vector tropism: adeno-associated virus (AAV) vectors, NMDAR 1 antisense and focal seizure sensitivity. Mol Ther 2002;6: 495–500.CrossRefPubMedGoogle Scholar
  10. 10.
    Haberman RP, McCown TJ, Samulski RJ. Inducible long-term gene expression in brain with adeno-associated virus gene transfer. Gene Ther 1998;5: 1604–1611.CrossRefPubMedGoogle Scholar
  11. 11.
    Sakurai E, Maeda T, Kaneko S, Akaike A, Satoh M. Galanin inhibits long-term potentiation at Schaffer collateral-CA1 synapses in guinea-pig hippocampal slices. Neurosci Lett 1996;5: 21–24.CrossRefGoogle Scholar
  12. 12.
    Liebowitz SF, Akabayashi A, Wang J. Obesity on a high-fat diet: role of hypothalamic galanin in neurons of the anterior paraventricular nucleus projecting to the median eminence. J Neurosci 1998;18: 2707–2719.Google Scholar
  13. 13.
    Mazarati AM, Liu H, Soomets U, et al. Galanin modulation of seizures and seizure modulation of hippocampal galanin in animal models of status epilepticus. J Neurosci 1998;18: 10070–10077.PubMedGoogle Scholar
  14. 14.
    Coumis U, Davies CH. The effects of galanin on long-term symaptic plasticity in the CA1 area of rodent hippocampus. Neurosci 2002;112: 173–182.CrossRefGoogle Scholar
  15. 15.
    Branchek RA, Smith KE, Gerald C, Walker MW. Galanin receptor subtypes. Trends Pharmacol Sci 2000;21: 109–117.CrossRefPubMedGoogle Scholar
  16. 16.
    Pieribone VA, Xu S-QD, Zhang X, Hökfelt T. Electrophysiologic effects of galanin on neurons of the central nervous system. Ann N Y Acad Sci 1998;863: 264–273.CrossRefPubMedGoogle Scholar
  17. 17.
    Fisone G, Wu CF, Consolo S, et al. Galanin inhibits acetylcholine release in the ventral hippocampus of the rat: histochemical, autoradiographic, in vivo and in vitro studies. Proc Nat Acad Sci USA 1987;84: 7339–7343.CrossRefPubMedGoogle Scholar
  18. 18.
    Zini S, Roisin MP, Lange U, Bartfai T, Ben-Ari Y. Galanin reduces release of endogenous excitatory amino acids in the rat hippocampus. Eur J Pharmacol 1993;245: 1–7.CrossRefPubMedGoogle Scholar
  19. 19.
    Mazarati AM, Wasterlain CG. Anticonvulsant effects of four neuropeptides in the rat hippocampus during self-sustaining status epilepticus. Neurosci Lett 2002;331: 123–127.CrossRefPubMedGoogle Scholar
  20. 20.
    Haberman RP, Samulski RJ, McCown TJ. Attenuation of seizures and neuronal death by adeno-associated virus (AAV) vector galanin expression and secretion. Nat Med 2003;9: 1076–1080.CrossRefPubMedGoogle Scholar
  21. 21.
    Lin EJ, Richichi C, Young D, Bauer K, Vezzani A, During MJ. Recombinant AAV-mediated expression of galanin in rat hippocampus suppresses seizure development. Eur J Neurosci 2003; 18: 2087–2092.CrossRefPubMedGoogle Scholar
  22. 22.
    McCown TJ. Adeno-associated virus-mediated expression and constitutive secretion of galanin suppresses limbic seizure activity in vivo. Mol Ther 2006; 14: 63–68.CrossRefPubMedGoogle Scholar

Copyright information

© The American Society for Experimental NeuroTherapeutics, Inc. 2009

Authors and Affiliations

  1. 1.UNC Gene Therapy Center, Department of PsychiatryUniversity of North Carolina at Chapel HillChapel Hill

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