Neurons have the intrinsic ability to regenerate after injury to the adult mammalian spinal cord as demonstrated by transplantation of either peripheral nerves, Schwann cells, or fetal spinal cord tissue. These axons regenerate into and throughout these transplants, but fail to grow significant distances back into the adult central nervous system (CNS). Axons that do regenerate into the adult CNS are randomly organized and not directed specifically towards their targets. Several hypotheses indicate that changes in the growth promoting state, either by active inhibition or the lack of a good growth supportive substrate, produce an environment that is refractory to axonal regeneration. This application is designed to examine the hypothesis that a selective expression of growth-supportive and guidance molecules can be used to increase axonal regeneration and direct these axons to select target regions. To test this hypothesis, we will examine axonal growth in two models. The first is the well-established dorsal root entry zone model to examine regeneration from separate sensory populations through the dorsal root entry zone (DREZ) and into the spinal cord. We have previously demonstrated robust axonal regeneration into both appropriate and aberrant targets. The first two specific aims will use this model. The second is a novel in vivo guidance model that uses an expression pathway to guide axonal growth from neuronal transplants towards a distant target location. We propose to accomplish the following specific aims: 1) to determine if co-expression of nerve growth factor (NGF) and semaphorin 3a within the adult spinal cord will direct the regeneration of sensory axons to appropriate target locations. 2) To enhance proprioceptive axonal regeneration by selective expression of neurotrophin (NT)-3 or tyrosine kinase (trk) C-receptor. 3) To direct the growth of axons from a neuronal transplant along a complex pathway to a distant target location. 4) To generate an expression pathway that can induce axonal growth from a transplant, through or around a lesion site, and towards a distant target location. For the proposed experiments, recombinant adenovirus will be used to transfer cellular adhesion molecules (CAMs), laminin neurotrophins, or chemorepulsive (e.g., semaphorin 3a) into the endogenous CNS environment. Regeneration of sensory axons through the DREZ and into the spinal cord will be examined using behavioral assessments for functional recovery and tract tracing techniques. This grant application is designed to better define the molecular mechanisms that influence axonal regeneration and guidance within the adult CNS, with the ultimate goal of inducing axonal regeneration in the spinal cord to appropriate locations, while discouraging aberrant connections.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS038126-06
Application #
6621343
Study Section
Special Emphasis Panel (ZRG1-BDCN-2 (01))
Program Officer
Kleitman, Naomi
Project Start
1999-01-01
Project End
2006-12-31
Budget Start
2003-01-01
Budget End
2003-12-31
Support Year
6
Fiscal Year
2003
Total Cost
$248,332
Indirect Cost
Name
University of Kentucky
Department
Physiology
Type
Schools of Medicine
DUNS #
939017877
City
Lexington
State
KY
Country
United States
Zip Code
40506
Kelamangalath, Lakshmi; Tang, Xiaoqing; Bezik, Kathleen et al. (2015) Neurotrophin selectivity in organizing topographic regeneration of nociceptive afferents. Exp Neurol 271:262-78
Lin, C-L; Heron, P; Hamann, S R et al. (2014) Functional distinction between NGF-mediated plasticity and regeneration of nociceptive axons within the spinal cord. Neuroscience 272:76-87
Chen, Qin; Smith, George M; Shine, H David (2008) Immune activation is required for NT-3-induced axonal plasticity in chronic spinal cord injury. Exp Neurol 209:497-509
Jin, Ying; Ziemba, Kristine S; Smith, George M (2008) Axon growth across a lesion site along a preformed guidance pathway in the brain. Exp Neurol 210:521-30
Curinga, Gabrielle; Smith, George M (2008) Molecular/genetic manipulation of extrinsic axon guidance factors for CNS repair and regeneration. Exp Neurol 209:333-42
Ziemba, Kristine S; Chaudhry, Nagarathnamma; Rabchevsky, Alexander G et al. (2008) Targeting axon growth from neuronal transplants along preformed guidance pathways in the adult CNS. J Neurosci 28:340-8
Heron, P M; Sutton, B M; Curinga, G M et al. (2007) Localized gene expression of axon guidance molecules in neuronal co-cultures. J Neurosci Methods 159:203-14
Tang, Xiao-Qing; Heron, Paula; Mashburn, Charles et al. (2007) Targeting sensory axon regeneration in adult spinal cord. J Neurosci 27:6068-78
Curinga, Gabrielle M; Snow, Diane M; Mashburn, Charles et al. (2007) Mammalian-produced chondroitinase AC mitigates axon inhibition by chondroitin sulfate proteoglycans. J Neurochem 102:275-88
Chaudhry, Nagarathnamma; de Silva, Udesh; Smith, George M (2006) Cell adhesion molecule L1 modulates nerve-growth-factor-induced CGRP-IR fiber sprouting. Exp Neurol 202:238-49

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