Up-regulation of the extracellular matrix glycoprotein tenascin-R during axonal reorganization and astrogliosis in the adult rat hippocampus.
Interactions between cells and extracellular matrix (ECM) molecules play a crucial role during brain development. The ECM glycoprotein tenascin-R (TN-R) has been implicated in the control of axon targeting, neural cell adhesion, migration and differentiation. Here, we have focused on the putative role of TN-R in chronic brain diseases involving increased neuronal excitability, as found in epilepsy. An episode of pilocarpine-induced status epilepticus (SE) led over a period of 3-30 days to neuron loss in the hippocampal hilus, CA3 and CA1 with reactive mossy fiber sprouting and astrogliosis in these regions. We found a focal up-regulation of granular TN-R immunoreactivity within the neuropil of segments of the CA3 pyramidal cell layer, the extent of this up-regulation paralleled the degree of pyramidal cell loss, mossy fiber sprouting and astrogliosis in these CA3 segments. In contrast, parvalbumin immunoreactivity and Wisteria floribundi agglutinin (WFA)-labeled perineuronal nets were reduced in CA3 segments with neuronal cell loss. The parallel development of increase in focal granular TN-R immunoreactivity, reactive mossy fiber sprouting and astrogliosis in CA3 implies a role for TN-R in axon targeting and synapse formation and/or in astrocytic targeting and interactions with the ECM during lesion-induced sprouting in the adult brain.
Brenneke
Franziska
F
Department of Epileptology, University of Bonn Medical Center, Sigmund-Freud Street 25, 53127 Bonn, Germany.
Schachner
Melitta
M
Elger
Christian E
CE
Lie
Ailing A
AA
D000818:Animals; D001253:Astrocytes / Q000737:chemistry / Q000378:metabolism*; D001369:Axons / Q000737:chemistry / Q000378:metabolism*; D004827:Epilepsy / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000032:analysis / Q000096:biosynthesis; D006624:Hippocampus / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D019063:Tenascin / Q000032:analysis / Q000096:biosynthesis*; D015854:Up-Regulation / Q000502:physiology*
D016326:Extracellular Matrix Proteins; D019063:Tenascin; C074638:tenascin R