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Neural Plasticity
Volume 2016 (2016), Article ID 3679545, 14 pages
http://dx.doi.org/10.1155/2016/3679545
Review Article

The Chemorepulsive Protein Semaphorin 3A and Perineuronal Net-Mediated Plasticity

1Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, Netherlands
2John van Geest Centre for Brain Repair, University of Cambridge, Cambridge CB2 OPY, UK
3Department of Neuroscience, Neuroscience Institute of Turin (NIT) and Neuroscience Institute Cavalieri-Ottolenghi (NICO), University of Turin, Orbassano, 10043 Turin, Italy

Received 18 September 2015; Accepted 10 December 2015

Academic Editor: Preston E. Garraghty

Copyright © 2016 F. de Winter et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

During postnatal development, closure of critical periods coincides with the appearance of extracellular matrix structures, called perineuronal nets (PNN), around various neuronal populations throughout the brain. The absence or presence of PNN strongly correlates with neuronal plasticity. It is not clear how PNN regulate plasticity. The repulsive axon guidance proteins Semaphorin (Sema) 3A and Sema3B are also prominently expressed in the postnatal and adult brain. In the neocortex, Sema3A accumulates in the PNN that form around parvalbumin positive inhibitory interneurons during the closure of critical periods. Sema3A interacts with high-affinity with chondroitin sulfate E, a component of PNN. The localization of Sema3A in PNN and its inhibitory effects on developing neurites are intriguing features and may clarify how PNN mediate structural neural plasticity. In the cerebellum, enhanced neuronal plasticity as a result of an enriched environment correlates with reduced Sema3A expression in PNN. Here, we first review the distribution of Sema3A and Sema3B expression in the rat brain and the biochemical interaction of Sema3A with PNN. Subsequently, we review what is known so far about functional correlates of changes in Sema3A expression in PNN. Finally, we propose a model of how Semaphorins in the PNN may influence local connectivity.