Neuroscience 2000 Abstract
| Presentation Number: | 217.5 |
|---|---|
| Abstract Title: | Distinct effects of laminin and L1 on NGF-induced axon extension. |
| Authors: |
Liu, R. Y.*1
; Schmid, R. S.2
; Maness, P. F.2
; Snider, W. D.1
1Neuroscience Center, Univ. of North Carolina, Chapel Hill, NC 2Biochemistry, Univ. of North Carolina School of Medicine, Chapel Hill, NC |
| Primary Theme and Topics |
A. Development and Regeneration - 6. Process outgrowth, growth cones and sprouting |
| Secondary Theme and Topics | A. Development and Regeneration<br />- 10. Expression and regulation of trophic factors: neurotrophins |
| Session: |
217. Process outgrowth: regulation by extracellular factors II Poster |
| Presentation Time: | Monday, November 6, 2000 8:00 AM-9:00 AM |
| Location: | Hall G-J |
| Keywords: | neural cell adhesion molecule, integrin, neurite outgrowth, neurotrophin |
Extracellular matrix molecules, cell adhesion molecules of the Ig superfamily and neurotrophins are all capable of promoting axon growth via common signal transduction pathways. However, potential interactions among these axon growth enhancing molecules have been difficult to study because of neuronal dependence on neurotrophin stimulation for survival. To circumvent this problem, we have cultured embryonic sensory neurons from Bax-/- mice, which do not undergo apoptosis in the absence of neurotrophins (Patel et al., Neuron 25, 345-357). We have measured axon extension on L1, laminin and the neutral substrate poly-D-lysine (PDL) with and without NGF. Both laminin and L1 support axon growth in the absence of neurotrophic stimulation in comparison to PDL. As previously reported many neurons plated on L1 exhibited growth cones with complex morphology compared to laminin. Mean axon length on the two substrates was similar at 48 hours (approx. 500μm). Concentrations of L1 between 150 and 600 ng/ml produced the same result. As expected, addition of NGF (50ng/ml) markedly enhanced axon growth on laminin (approx. 3 fold at 48 hrs). In striking contrast, addition of NGF had no significant effect on L1-dependent axon growth. Indeed axon length on L1 was slightly less at 48 hrs in the presence of NGF (500μm - L1, 450μm - L1+NGF). We conclude that extracellular matrix molecules and Ig superfamily members have distinct regulatory effects on NGF-induced axon growth. We propose that distinct interactions of L1 and integrins with the cytoskeleton may importantly influence the degree of axon extension induced by NGF.
Supported by NIH grant NS 31768
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2000 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2000. Online.
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