Ta. Mitsiadis et al., Reactivation of Delta-Notch signaling after injury: Complementary expression patterns of ligand and receptor in dental pulp, EXP CELL RE, 246(2), 1999, pp. 312-318
The evolutionarily conserved Notch-mediated intercellular signaling pathway
is essential for proper embryonic development of many tissues and organs.
Recent data suggest that Notch receptors and their membrane-bound ligands D
elta and Serrate are involved in both patterning and cell fate determinatio
n during odontogenesis. It remains, however, uncertain if Notch signaling i
s important for tooth homeostasis and regeneration. Here we report on the e
xpression of Notch receptors and the Delta1 ligand in dental pulp of normal
and injured adult rat teeth, Notch receptors were absent from normal adult
dental tissues, whereas expression was upregulated after injury, In injure
d teeth, Notch2 was expressed in mesenchymal cells of the pulp both close t
o the site of injury (i.e., in the dental crown) and at a distance from it
(i.e., in the dental roots), Notch3 expression was mainly associated with v
ascular structures, while Notch1 expression was restricted to few pulpal ce
lls close to the lesion. None of them was expressed in odontoblasts. Expres
sion of Delta1 was upregulated in odontoblasts of the injured teeth, as wel
l as in vascular structures, These results demonstrate the reactivation of
the Notch signaling pathway during wound healing and, furthermore, highligh
t the similarity between developmental and regenerative processes. (C) 1999
Academic Press.