A Synthetic Peptide Ligand of Neural Cell Adhesion Molecule (NCAM), C3d, Promotes Neuritogenesis and Synaptogenesis and Modulates Presynaptic Function in Primary Cultures of Rat Hippocampal Neurons

Galina Skladchikova,Vladimir Berezin,Darya Kiryushko,Elisabeth Bock,Thomas Kofoed,Arne Holm

doi:10.1074/jbc.m211628200

Abstract

The neural cell adhesion molecule (NCAM) plays a key role in morphogenesis of the nervous system and in remodeling of neuronal connections accompanying regenerative and cognitive processes. Recently, a new synthetic ligand of NCAM, the C3-peptide, which binds to the NCAM IgI module, has been identified by means of combinatorial chemistry (Rønn, L. C. B, Olsen, M., Ostergaard, S., Kiselyov, V., Berezin, V., Mortensen, M. T., Lerche, M. H., Jensen, P. H., Soroka, V., Saffell, J. L., Doherty, P., Poulsen, F. M., Bock, E., Holm, A., and Saffells, J. L. (1999) Nat. Biotechnol. 17, 1000-1005). In vitro, the dendrimeric form of C3, termed C3d, disrupts NCAM-mediated cell adhesion, induces neurite outgrowth, and triggers intracellular signaling cascades similar to those activated by homophilic NCAM binding. The peptide may therefore be expected to regulate regeneration and synaptic plasticity. Here we demonstrate that in primary cultures of hippocampal neurons: 1) C3d induces a sustained neuritogenic response, the neuritogenic activity of the compound being dependent on the dose, starting time, and duration of peptide application; 2) the peptide triggers the neuritogenic response by forming an adhesive substratum necessary for NCAM-mediated neurite formation and elongation; 3) C3d promotes synapse formation; and 4) C3d modulates the presynaptic function, causing a transient increase of the function at low (2 and 5 microm) doses and a reduction when applied at a higher concentration (10 microm). The effect of the peptide is dependent on the activation of the fibroblast growth factor receptor. We suggest that C3d may constitute a useful lead for the development of compounds for treatment of various neurodegenerative disorders.

Highlights

The neural cell adhesion molecule (NCAM)1 plays a key role in morphogenesis of the nervous system [2] and in remodeling of neuronal connections associated with regenerative and cognitive processes
We demonstrate that in primary cultures of hippocampal neurons: 1) C3d induces a sustained neuritogenic response, the neuritogenic activity of the compound being dependent on the dose, starting time, and duration of peptide application; 2) the peptide triggers the neuritogenic response by forming an adhesive substratum necessary for NCAM-mediated neurite formation and elongation; 3) C3d promotes synapse formation; and 4) C3d modulates the presynaptic function, causing a transient increase of the function at low (2 and 5 ␮M) doses and a reduction when applied at a higher concentration (10 ␮M)
We investigate the kinetics of the neuritogenic effect of C3d and show that by providing an adhesive substratum for neurite promotion, the peptide induces both a persistent neuritogenic response from primary hippocampal neurons and the formation of functional synapses, with synaptogenesis accelerated in cultures grown on C3d versus control substratum

Summary

Introduction

The neural cell adhesion molecule (NCAM)1 plays a key role in morphogenesis of the nervous system [2] and in remodeling of neuronal connections associated with regenerative and cognitive processes (for review, see Ref. 3). The dendrimeric form of C3, termed C3d, disrupts NCAM-mediated cell adhesion, induces neurite outgrowth, and triggers intracellular signaling cascades similar to those activated by homophilic NCAM binding.

Results

Conclusion