Neuroscience 2005 Abstract
| Presentation Number: | 103.6 |
|---|---|
| Abstract Title: | Neutralization of netrin-1 increases axon outgrowth on adult spinal cord myelin. |
| Authors: |
Loew, K. I.*1
; Tessier-Lavigne, M.2
; Tuszynski, M. H.1
1Dept Neurosci, UCSD School of Medicine, La Jolla, CA 2CA, Basic Sci Bldg Rm 4046, 92093-0626, |
| Primary Theme and Topics |
Sensory and Motor Systems - Spinal Cord -- Injury and recovery |
| Session: |
103. Spinal Cord Injury: Axon Regeneration Poster |
| Presentation Time: | Saturday, November 12, 2005 2:00 PM-3:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # TT63 |
| Keywords: | spinal cord injury, myelin inhibitors |
We tested the hypothesis that netrin is as an inhibitor to axon growth in adult white matter. An in vitro assay was established to neutralize potential netrin-mediated inhibition of axon outgrowth via Unc5 receptor signaling. Embryonic day 15 (E15) rat spinal cords were isolated, motor columns were dissected and Unc5H1- and Unc5H3- expressing motor neurons were enzymatically dissociated and plated on coverslips that were coated with myelin prepared from adult rat spinal cord. Unc5H2 receptor bodies, fusion proteins between the extracellular domain of the netrin receptor Unc5H2 and human Fc IgG, were engineered to neutralize netrin-1.
Axon outgrowth from E15 spinal motor neurons increased by 82% (p < 0.001) after treatment of myelin with soluble Unc5H2 receptor bodies, from a mean neurite length of 49 µm +/- 0.6 µm (SEM) using control Fc to 89 µm +/- 1.3 µm (SEM) using the receptor body. Effects were observed in a dose dependent manner. These results suggest that physiological levels of netrin-1 contained within myelin of the adult spinal cord inhibit axon outgrowth from Unc5-expressing neurons. Unc5-expressing adult neurons include corticospinal neurons, rubrospinal neurons and proriospinal neurons throughout the spinal cord gray matter.
Axon outgrowth from E15 spinal motor neurons increased by 82% (p < 0.001) after treatment of myelin with soluble Unc5H2 receptor bodies, from a mean neurite length of 49 µm +/- 0.6 µm (SEM) using control Fc to 89 µm +/- 1.3 µm (SEM) using the receptor body. Effects were observed in a dose dependent manner. These results suggest that physiological levels of netrin-1 contained within myelin of the adult spinal cord inhibit axon outgrowth from Unc5-expressing neurons. Unc5-expressing adult neurons include corticospinal neurons, rubrospinal neurons and proriospinal neurons throughout the spinal cord gray matter.
Supported by NIH
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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