Developmentally regulated expression of brain-specific chondroitin sulfate proteoglycans, neurocan and phosphacan, in the postnatal rat hippocampus

Abstract

Developmental changes in the distribution of brain-specific chondroitin sulfate proteoglycans, neurocan and phosphacan/RPTPzeta/beta, in the hippocampus of the Sprague-Dawley rat were examined using monoclonal antibodies 1G2 and 6B4. The 1G2 immunoreactivity was predominant in the neonatal hippocampus while the 6B4 immunoreactivity was predominant in the mature hippocampus. Moderate 1G2 immunoreactivity was detected in the dentate gyrus and subiculum immediately after birth. Immunoreactivity reached a peak on postnatal days 7-10 (P7-P10) when intense 1G2 labeling was present throughout the neuropil layers of the hippocampus except the mossy fiber tract. 6B4 immunoreactivity was limited in the stratum lacunosum moleculare of CA1 in the neonatal hippocampus. It gradually increased by P21 when diffuse 6B4 immunoreactivity was detected in the stratum oriens and radiatum of Ammon's horn, and in the hilus and inner one-third molecular layer of the dentate gyrus, while 1G2 immunoreactivity decreased after P21. In the adult hippocampus, moderate 6B4 immunoreactivity was present in the stratum oriens and radiatum of Ammon's horn, and in the hilus and inner one-third molecular layer of the dentate gyrus, but not in the mossy fiber tract. In addition, strong 6B4 labeling appeared around a subset of neurons after P21. The results suggest that neurocan may have a role in the development of neuronal organization, while phosphacan/RPTPzeta/beta may contribute to the maintenance and plasticity of synaptic structure and function. Furthermore, the absence of 1G2 and 6B4 immunoreactivities in the stratum lucidum suggests that neurocan and phosphacan/RPTPzeta/beta may function as a barrier for the extension of mossy fibers and provide an environment permissive for fasciculation of the mossy fibers.

Phosphacan and receptor protein tyrosine phosphatase β expression mediates deafferentation‐induced synaptogenesis

“…In contrast, our results suggest that UEC does not induce astrocyte production of phosphacan, but rather granule cells are a principal source of phosphacan after lesion and facilitate its redistribution to areas undergoing reactive synaptogenesis. This interpretation is consistent with prior observations by Okamoto et al (2001) which show that phosphacan is not colocalized to astrocytes within adult hippocampus.…”

Localization of chondroitin sulfate proteoglycan versican in adult brain with special reference to large projection neurons

“…On the other hand, inhibitory interneurons in the cerebral cortex, hippocampus, striatum, and cerebellar stellate cells are not labeled by the GAGα antibody. These results are interesting, because other CSPGs, neurocan, aggrecan, and phosphacan are localized around Pv-labeled interneurons and construct perineuronal nets around them (Matthews et al 2002;McRae et al 2007;Matsui et al 1994;Okamoto et al 2001). The present double-labeling of GAGα with WFA and phosphacan shows the absence of versican from these perineuronal nets.…”

The perineuronal net component of the extracellular matrix in plasticity and epilepsy

“…Their expression has been linked to sculpting of axonal path finding, cell adhesion, elongation, process outgrowth, branching, and synapse formation and plasticity (Engel et al, 1996; Meyer-Puttlitz et al, 1996; Margolis et al, 1996; Margolis and Margolis, 1997; Garwood et al, 2001; Zhou et al, 2001; Okamoto et al, 2001; Faissner et al, 2006). Neurocan is expressed around the developing mossy fiber tract and has been proposed to act as a barrier for directing mossy fiber extension (Seki and Rutishauser, 1998; Okamoto et al, 2001). Neurocan expression peaks during development with little expression in the adult (Yamaguchi 1996); however, following SE it is re-expressed in the adult hippocampus (Kurazono et al, 2001; Matsui et al, 2002; Heck et al, 2004).…”