Composition of Perineuronal Net Extracellular Matrix in Rat Brain

Abstract

We developed a method to extract differentially chondroitin sulfate proteoglycans (CSPGs) that are diffusely present in the central nervous system (CNS) matrix and CSPGs that are present in the condensed matrix of perineuronal nets (PNNs). Adult rat brain was sequentially extracted with Tris-buffered saline (TBS), TBS-containing detergent, 1 M NaCl, and 6 M urea. Extracting tissue sections with these buffers showed that the diffuse and membrane-bound CSPGs were extracted in the first three buffers, but PNN-associated CSPGs remained and were only removed by 6 M urea. Most of the CSPGs were extracted to some degree with all the buffers, with neurocan, brevican, aggrecan, and versican particularly associated with the stable urea-extractable PNNs. The CSPGs in stable complexes only extractable in urea buffer are found from postnatal day 7-14 coinciding with PNN formation. Disaccharide composition analysis indicated a different glycosaminoglycan (GAG) composition for PGs strongly associated with extracellular matrix (ECM). For CS/dermatan sulfate (DS)-GAG

Oligodendrocyte Precursor Cells Modulate the Neuronal Network by Activity-Dependent Ectodomain Cleavage of Glial NG2

“…The NG2 ectodomain of 290 kD can be extracted with PBS from the ECM of the rodent brain (Figures 3B and S1) [31],[32]. To analyze the effect of activity-dependent effects of the whole neural network on NG2 cleavage within OPC, we subjected acute hippocampal slices to cLTP (PFR incubation) or incubation with 4AP + BCC and analyzed levels of the released NG2 ectodomain.…”

“…Acute rat hippocampal slices [84] were incubated for 15 min with PFR or 4AP + BCC and subsequently transferred to standard artificial cerebrospinal fluid (aCSF) without Mg 2+ and protease inhibitors, followed by tissue digestion with chondroitinase ABC [32] and Western Blot analysis.…”

“…An NG2 ectodomain has been reported to be extractable in aqueous buffers from the extracellular matrix (ECM), suggesting that NG2 cleavage occurs in vivo in the normal CNS [31],[32]. Recent results demonstrated activity-dependent cleavage of the synaptic neuronal adhesion molecules N-cadherin and neuroligin1 by the α-secretase ADAM10 with subsequent modifications of synaptic structure and function [33],[34].…”

Functions of Chondroitin Sulfate and Heparan Sulfate in the Developing Brain

“…However, recent studies indicated that adult brain as well as immature brain is enriched with extracellular matrix components [82]. Unlike the extracellular matrices of other tissues, those of the brain lack collagen fibers, and are composed mainly of proteoglycans, tenascins and hyaluronic acid.…”

Molecular mechanisms of scar-sourced axon growth inhibitors

“…The CSPG binding may convert Sema5A from an attractive to an inhibitory guidance cue (Kantor et al, 2004). Sema3A, a repulsive guidance molecule, may interact with CS-E enriched in the PNNs and this interaction could mediate the repulsive function of Sema3A (De Wit et al, 2005; Deepa et al, 2006; Kwok et al, 2011). In addition, the GAGs of CSPGs may bind to extracellular calcium or its channels and regulate neuronal growth by affecting calcium availability and entry into neurons (Hrabetova et al, 2009).…”