Glutamatergic cerebellar granule neurons synthesize and secrete reelin in vitro.
In the postnatal forebrain, the extracellular matrix protein reelin is expressed and secreted by subsets of GABAergic neurons, whereas in the cerebellum reelin is detected in glutamatergic cells of the granule cell layer. Thus, various regions of the postnatal brain present different patterns of reelin expression, whose significance remains unknown. We combined immunocytochemical and pharmacological approaches to characterize the phenotypic and temporal profiles of reelin expression in dissociated cultures of cerebellar granule neurons. A single type of reelin immunoreactivity, identified by a punctate labelling, was present in the somata of the majority of neurons. This immunoreactivity was observed throughout maturation and was exclusively present in glutamatergic neurons expressing the vesicular glutamate transporter 1. Neurons containing the reelin receptors apolipoprotein E receptor 2 (Apoer2) and very low-density lipoprotein receptor (Vldlr) represented about 80% of cerebellar neurons. The vast majority of reelin-positive neurons coexpressed Apoer2, suggesting that reelin immunoreactivity resulted in part from receptor-bound reelin. Inhibition of protein synthesis with cycloheximide completely abolished reelin immunoreactivity. In contrast, blocking protein secretion with brefeldin A did not affect the proportion of punctate neurons but revealed a subpopulation of neurons characterized by a solid reelin staining. These data show for the first time that a homogeneous population of glutamatergic neurons can synthesize and secrete reelin in cerebellar granule cells in vitro.
Sinagra
Mélanie
M
INSERM U862, Neurocentre Magendie, Pathophysiology of Synaptic Plasticity, 146 rue Léo Saignat, Bordeaux, F-33000, France.
Gonzalez Campo
Cecilia
C
Verrier
Danièle
D
Moustié
Olivier
O
Manzoni
Olivier J
OJ
Chavis
Pascale
P
D000818:Animals; D000831:Animals, Newborn; D020126:Brefeldin A / Q000494:pharmacology; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism*; D002452:Cell Count / Q000379:methods; D002531:Cerebellum / Q000166:cytology*; D003513:Cycloheximide / Q000494:pharmacology; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005968:Glutamate Decarboxylase / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism*; D026502:LDL-Receptor Related Proteins; D051379:Mice; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011973:Receptors, LDL / Q000378:metabolism; D018110:Receptors, Lipoprotein / Q000378:metabolism; D000091042:Reelin Protein; D012697:Serine Endopeptidases / Q000378:metabolism*; D013997:Time Factors; D050598:Vesicular Glutamate Transport Protein 1 / Q000378:metabolism; D050495:Vesicular Inhibitory Amino Acid Transport Proteins / Q000378:metabolism
D015816:Cell Adhesion Molecules, Neuronal; D016326:Extracellular Matrix Proteins; D026502:LDL-Receptor Related Proteins; D009419:Nerve Tissue Proteins; D011500:Protein Synthesis Inhibitors; D011973:Receptors, LDL; D018110:Receptors, Lipoprotein; D000091042:Reelin Protein; C493465:Slc17a7 protein, mouse; C036053:VLDL receptor; D050598:Vesicular Glutamate Transport Protein 1; D050495:Vesicular Inhibitory Amino Acid Transport Proteins; C492244:Viaat protein, mouse; C098773:low density lipoprotein receptor-related protein 8; D020126:Brefeldin A; D018698:Glutamic Acid; D003513:Cycloheximide; C000717128:Reln protein, mouse; D012697:Serine Endopeptidases; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1