The assessment of adeno-associated vectors as potential intrinsic treatments for brainstem axon regeneration

Ryan R. Williams, Damien D Pearse, Patrick A. Tresco, Mary B Bunge

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Background Adeno-associated virus (AAV) vector-mediated transgene expression is a promising therapeutic to change the intrinsic state of neurons and promote repair after central nervous system injury. Given that numerous transgenes have been identified as potential candidates, the present study demonstrates how to determine whether their expression by AAV has a direct intrinsic effect on axon regeneration. Methods: Serotype 2 AAV-enhanced green fluorescent protein (EGFP) was stereotaxically injected into the brainstem of adult rats, followed by a complete transection of the thoracic spinal cord and Schwann cell (SC) bridge implantation. Results: The expression of EGFP in brainstem neurons labeled numerous axons in the thoracic spinal cord and that regenerated into the SC bridge. The number of EGFP-labeled axons rostral to the bridge directly correlated with the number of EGFP-labeled axons that regenerated into the bridge. Animals with a greater number of EGFP-labeled axons rostral to the bridge exhibited an increased percentage of those axons found near the distal end of the bridge compared to animals with a lesser number. This suggested that EGFP may accumulate distally in the axon with time, enabling easier visualization. By labeling brainstem axons with EGFP before injury, numerous axon remnants undergoing Wallerian degeneration may be identified distal to the complete transection up to 6weeks after injury. Conclusions: Serotype 2 AAV-EGFP enabled easy visualization of brainstem axon regeneration. Rigorous models of axonal injury (i.e. complete transection and cell implantation) should be used in combination with AAV-EGFP to directly assess AAV-mediated expression of therapeutic transgenes as intrinsic treatments to improve axonal regeneration.

Original languageEnglish
Pages (from-to)20-34
Number of pages15
JournalJournal of Gene Medicine
Volume14
Issue number1
DOIs
StatePublished - Jan 1 2012

Fingerprint

Brain Stem
Axons
Regeneration
Dependovirus
Transgenes
Schwann Cells
Wounds and Injuries
Thorax
Wallerian Degeneration
Nervous System Trauma
enhanced green fluorescent protein
Neurons
Spinal Cord Injuries
Spinal Cord
Central Nervous System
Therapeutics

Keywords

  • Adeno-associated viral vector
  • Axon regeneration
  • Enhanced green fluorescent protein
  • Schwann cell
  • Spinal cord injury
  • Wallerian degeneration

ASJC Scopus subject areas

  • Genetics
  • Molecular Biology
  • Molecular Medicine
  • Genetics(clinical)
  • Drug Discovery

Cite this

The assessment of adeno-associated vectors as potential intrinsic treatments for brainstem axon regeneration. / Williams, Ryan R.; Pearse, Damien D; Tresco, Patrick A.; Bunge, Mary B.

In: Journal of Gene Medicine, Vol. 14, No. 1, 01.01.2012, p. 20-34.

Research output: Contribution to journalArticle

@article{12a087762881420cbe70c8e20db9204c,
title = "The assessment of adeno-associated vectors as potential intrinsic treatments for brainstem axon regeneration",
abstract = "Background Adeno-associated virus (AAV) vector-mediated transgene expression is a promising therapeutic to change the intrinsic state of neurons and promote repair after central nervous system injury. Given that numerous transgenes have been identified as potential candidates, the present study demonstrates how to determine whether their expression by AAV has a direct intrinsic effect on axon regeneration. Methods: Serotype 2 AAV-enhanced green fluorescent protein (EGFP) was stereotaxically injected into the brainstem of adult rats, followed by a complete transection of the thoracic spinal cord and Schwann cell (SC) bridge implantation. Results: The expression of EGFP in brainstem neurons labeled numerous axons in the thoracic spinal cord and that regenerated into the SC bridge. The number of EGFP-labeled axons rostral to the bridge directly correlated with the number of EGFP-labeled axons that regenerated into the bridge. Animals with a greater number of EGFP-labeled axons rostral to the bridge exhibited an increased percentage of those axons found near the distal end of the bridge compared to animals with a lesser number. This suggested that EGFP may accumulate distally in the axon with time, enabling easier visualization. By labeling brainstem axons with EGFP before injury, numerous axon remnants undergoing Wallerian degeneration may be identified distal to the complete transection up to 6weeks after injury. Conclusions: Serotype 2 AAV-EGFP enabled easy visualization of brainstem axon regeneration. Rigorous models of axonal injury (i.e. complete transection and cell implantation) should be used in combination with AAV-EGFP to directly assess AAV-mediated expression of therapeutic transgenes as intrinsic treatments to improve axonal regeneration.",
keywords = "Adeno-associated viral vector, Axon regeneration, Enhanced green fluorescent protein, Schwann cell, Spinal cord injury, Wallerian degeneration",
author = "Williams, {Ryan R.} and Pearse, {Damien D} and Tresco, {Patrick A.} and Bunge, {Mary B}",
year = "2012",
month = "1",
day = "1",
doi = "10.1002/jgm.1628",
language = "English",
volume = "14",
pages = "20--34",
journal = "Journal of Gene Medicine",
issn = "1099-498X",
publisher = "John Wiley and Sons Ltd",
number = "1",

}

TY - JOUR

T1 - The assessment of adeno-associated vectors as potential intrinsic treatments for brainstem axon regeneration

AU - Williams, Ryan R.

AU - Pearse, Damien D

AU - Tresco, Patrick A.

AU - Bunge, Mary B

PY - 2012/1/1

Y1 - 2012/1/1

N2 - Background Adeno-associated virus (AAV) vector-mediated transgene expression is a promising therapeutic to change the intrinsic state of neurons and promote repair after central nervous system injury. Given that numerous transgenes have been identified as potential candidates, the present study demonstrates how to determine whether their expression by AAV has a direct intrinsic effect on axon regeneration. Methods: Serotype 2 AAV-enhanced green fluorescent protein (EGFP) was stereotaxically injected into the brainstem of adult rats, followed by a complete transection of the thoracic spinal cord and Schwann cell (SC) bridge implantation. Results: The expression of EGFP in brainstem neurons labeled numerous axons in the thoracic spinal cord and that regenerated into the SC bridge. The number of EGFP-labeled axons rostral to the bridge directly correlated with the number of EGFP-labeled axons that regenerated into the bridge. Animals with a greater number of EGFP-labeled axons rostral to the bridge exhibited an increased percentage of those axons found near the distal end of the bridge compared to animals with a lesser number. This suggested that EGFP may accumulate distally in the axon with time, enabling easier visualization. By labeling brainstem axons with EGFP before injury, numerous axon remnants undergoing Wallerian degeneration may be identified distal to the complete transection up to 6weeks after injury. Conclusions: Serotype 2 AAV-EGFP enabled easy visualization of brainstem axon regeneration. Rigorous models of axonal injury (i.e. complete transection and cell implantation) should be used in combination with AAV-EGFP to directly assess AAV-mediated expression of therapeutic transgenes as intrinsic treatments to improve axonal regeneration.

AB - Background Adeno-associated virus (AAV) vector-mediated transgene expression is a promising therapeutic to change the intrinsic state of neurons and promote repair after central nervous system injury. Given that numerous transgenes have been identified as potential candidates, the present study demonstrates how to determine whether their expression by AAV has a direct intrinsic effect on axon regeneration. Methods: Serotype 2 AAV-enhanced green fluorescent protein (EGFP) was stereotaxically injected into the brainstem of adult rats, followed by a complete transection of the thoracic spinal cord and Schwann cell (SC) bridge implantation. Results: The expression of EGFP in brainstem neurons labeled numerous axons in the thoracic spinal cord and that regenerated into the SC bridge. The number of EGFP-labeled axons rostral to the bridge directly correlated with the number of EGFP-labeled axons that regenerated into the bridge. Animals with a greater number of EGFP-labeled axons rostral to the bridge exhibited an increased percentage of those axons found near the distal end of the bridge compared to animals with a lesser number. This suggested that EGFP may accumulate distally in the axon with time, enabling easier visualization. By labeling brainstem axons with EGFP before injury, numerous axon remnants undergoing Wallerian degeneration may be identified distal to the complete transection up to 6weeks after injury. Conclusions: Serotype 2 AAV-EGFP enabled easy visualization of brainstem axon regeneration. Rigorous models of axonal injury (i.e. complete transection and cell implantation) should be used in combination with AAV-EGFP to directly assess AAV-mediated expression of therapeutic transgenes as intrinsic treatments to improve axonal regeneration.

KW - Adeno-associated viral vector

KW - Axon regeneration

KW - Enhanced green fluorescent protein

KW - Schwann cell

KW - Spinal cord injury

KW - Wallerian degeneration

UR - http://www.scopus.com/inward/record.url?scp=84862966021&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84862966021&partnerID=8YFLogxK

U2 - 10.1002/jgm.1628

DO - 10.1002/jgm.1628

M3 - Article

C2 - 22106053

AN - SCOPUS:84862966021

VL - 14

SP - 20

EP - 34

JO - Journal of Gene Medicine

JF - Journal of Gene Medicine

SN - 1099-498X

IS - 1

ER -