Distribution and synthesis of extracellular matrix proteoglycans, hyaluronan, link proteins and tenascin-R in the rat spinal cord.
Perineuronal nets (PNNs) are dense extracellular matrix (ECM) structures that form around many neuronal cell bodies and dendrites late in development. They contain several chondroitin sulphate proteoglycans (CSPGs), hyaluronan, link proteins and tenascin-R. Their time of appearance correlates with the ending of the critical period for plasticity, and they have been implicated in this process. The distribution of PNNs in the spinal cord was examined using Wisteria floribunda agglutinin lectin and staining for chondroitin sulphate stubs after chondroitinase digestion. Double labelling with the neuronal marker, NeuN, showed that PNNs were present surrounding approximately 30% of motoneurons in the ventral horn, 50% of large interneurons in the intermediate grey and 20% of neurons in the dorsal horn. These PNNs formed in the second week of postnatal development. Immunohistochemical staining demonstrated that the PNNs contain a mixture of CSPGs, hyaluronan, link proteins and tenascin-R. Of the CSPGs, aggrecan was present in all PNNs while neurocan, versican and phosphacan/RPTPbeta were present in some but not all PNNs. In situ hybridization showed that aggrecan and cartilage link protein (CRTL 1) and brain link protein-2 (BRAL 2) are produced by neurons. PNN-bearing neurons express hyaluronan synthase, and this enzyme and phosphacan/RPTPbeta may attach PNNs to the cell surface. During postnatal development the expression of link protein and aggrecan mRNA is up-regulated at the time of PNN formation, and these molecules may therefore trigger their formation.
Galtrey
Clare M
CM
Cambridge Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Robinson Way, Cambridge, CB2 2PY, UK.
Kwok
Jessica C F
JC
Carulli
Daniela
D
Rhodes
Kate E
KE
Fawcett
James W
JW
D000818:Animals; D000831:Animals, Newborn; D003712:Dendrites / Q000737:chemistry / Q000378:metabolism; D005109:Extracellular Matrix / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D006820:Hyaluronic Acid / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000737:chemistry / Q000378:metabolism; D011509:Proteoglycans / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism*; D019063:Tenascin / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D000099249:Proteoglycan Link Protein
D016326:Extracellular Matrix Proteins; D006820:Hyaluronic Acid; D011509:Proteoglycans; D019063:Tenascin; D000099249:Proteoglycan Link Protein; C074638:tenascin R