Expression and localization of reelin in human odontoblasts.
Reelin is a large extracellular matrix (ECM) glycoprotein strongly expressed during embryonic development in the central nervous system and involved in architectonic brain development. It could participate in axon plasticity processes or adhesion-recognition between nerve fibers in adulthood. Previously identified from a subtractive cDNA library of fully differentiated human odontoblasts, reelin might be involved in the relationship between dental nerves and odontoblasts in as so far the latter are in close association with pulpal nerve fibers. Here, we show by in situ hybridization and immunohistochemistry that reelin is specifically expressed by human odontoblasts in vivo and in vitro and that an intense expression of the reelin gene is detected in odontoblasts in comparison with pulpal cells (PC). Co-cultures of rat trigeminal ganglion (TG) and odontoblasts allow to mimic odontoblast innervation and demonstrate that neurites contact these cells with reelin molecules as observed in vivo in human dental pulp. Moreover, by RT-PCR, we show that both reelin receptors (namely apolipoprotein E receptor [ApoER-2], very low density lipoprotein receptor [VLDLR] and cadherin-related neuronal receptor [CNR]) and the cytoplasmic adapter Disabled-1 implicated in the reelin signal transduction, were expressed by trigeminal ganglion. On the basis of these data, we suggest that reelin might be an extracellular matrix molecule involved in the terminal innervation of the dentin-pulp complex, promoting adhesion between dental nerve endings and odontoblasts.
Laboratoire du Développement des Tissus Dentaires, EA 1892, IFR 62, Faculté d'Odontologie, Rue Guillaume Paradin, 69372 CEDEX08 Lyon, France.
Jean-Christophe
JC
Maurin
Marie-Lise
ML
Couble
Marianne
M
Didier-Bazes
Christine
C
Brisson
Henry
H
Magloire
Françoise
F
Bleicher
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000293:Adolescent; D000818:Animals; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism*; D002478:Cells, Cultured; D018920:Coculture Techniques; D003782:Dental Pulp / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D009419:Nerve Tissue Proteins / Q000378:metabolism; D016501:Neurites / Q000502:physiology; D009804:Odontoblasts / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011956:Receptors, Cell Surface / Q000378:metabolism; D000091042:Reelin Protein; D012697:Serine Endopeptidases; D012668:Trigeminal Ganglion / Q000502:physiology
D048868:Adaptor Proteins, Signal Transducing; D015816:Cell Adhesion Molecules, Neuronal; C115785:DAB1 protein, human; C499786:Dab1 protein, rat; D016326:Extracellular Matrix Proteins; D009419:Nerve Tissue Proteins; D011956:Receptors, Cell Surface; D000091042:Reelin Protein; C000717129:Reln protein, rat; C469363:reelin receptor; C000717127:RELN protein, human; D012697:Serine Endopeptidases