Expression of neural cell adhesion molecule (NCAM) during the first molar development in the mouse

Abstract

NCAM, the neural cell adhesion molecule, was immunolocalized in the mandibular first molar tooth germ of the mouse. NCAM was first detected in the tooth germ of the late bud stage, where only the cells in the outer part of the condensed mesenchyme (primitive dental follicle) exhibited faint immunoreactivity. The entire dental follicle was intensely immunostained for NCAM from cap stage to the stage when root formation started. During root formation, NCAM disappeared from the follicular tissue surrounding the cervical root as well as from the part covering the crown top. This loss of NCAM proceeded in the direction of the root apex, but even after the tooth had achieved functional occlusion, NCAM was still expressed by the mesenchymal cells adjacent to the root apex. On the other hand, NCAM was negative in the dental papilla until birth. After birth, NCAM-immunoreactivity appeared in the basal portion of the dental papilla, but this NCAM-positive area gradually diminished in width during the root elongation. Instead, another NCAM-positive zone appeared in the core of the pulp during root formation. Even in the tooth that had already erupted, the pulp core contained cells that were strongly positive for NCAM immunostaining. In addition to its expression in the above two mesenchymal cell lineages, NCAM was transiently expressed by epithelial components of the tooth germ, some of the cells of the dental lamina and the enamel organ. The results suggest that NCAM participates in several processes of tooth development.

Coordination of trigeminal axon navigation and patterning with tooth organ formation: epithelial-mesenchymal interactions, and epithelial Wnt4 and Tgfβ1 regulate semaphorin 3a expression in the dental mesenchyme

“…Nerve growth factor (Ngf), which is essential for tooth innervation (Matsuo et al, 2001;Qian and Naftel, 1996), is expressed in the mesenchymal axon pathway, and, later, together with glial cell line-derived neurotrophic factor (Gdnf), in the dental follicle target area around the tooth germ (Luukko et al, 1997a;Luukko et al, 1997c;Mitsiadis et al, 1992;Nosrat et al, 1998). Similarly, the neural cell adhesion molecule (Ncam) and low-affinity neurotrophin receptor (Lanr), which may sequester neurotrophins, are present in the dental follicle target field during axon navigation (Luukko et al, 1996;Mitsiadis et al, 1992;Obara and Takeda, 1993). In addition, mRNAs for netrin 3 (Net3) are expressed in the mesenchymal axon pathway and dental follicle region and may therefore be involved in the regulation of dental axon growth (Loes et al, 2003).…”

Developmentally regulated expression of Netrin‐1 and ‐3 in the embryonic mouse molar tooth germ

“…However, we did not observe disturbances in Net-1 mutant mice, suggesting that Net-1 does not serve a critical role in embryonic tooth axon guidance or in early tooth histo-organogenesis. Local expression of several putative axonal guidance molecules such as NGF, N-CAM, NGF, GDNF, and Neurturin as well as Net-3 (see below) in the tooth axon pathways (Mitsiadis et al, 1992;Obara and Takeda, 1993;Luukko et al, 1997aLuukko et al, ,b, 1998Nosrat et al, 1998Nosrat et al, , 2002 raises the possibility that a lack of proper Net-1 signaling in Net -/-mice may be compensated for by other neuroregulatory molecules.…”

“…NGF receptor trkA-deficient mice show complete loss of nerve fibers in tooth pulp (Matsuo et al, 2001). Neural cell adhesion molecule (N-CAM) and chemorepellant Sema3A appear to be locally involved in axon guidance in the tooth target field (Obara and Takeda, 1993;Løes et al, 2001). However, only little is known about the molecular guidance mechanism behind pioneer axon navigation to the developing tooth germ.…”

“…In the lower molar, the nerve fibers emerge from the mandibular nerve trunk and navigate to the tooth target region as a single axon projection (Luukko, 1997;Løes et al, 2002). In the mouse, the nerve trajectory is located next to the condensed dental mesenchyme at the buccal side of the E13 bud stage tooth germ (Mohammed and Atkinson, 1983;Obara and Takeda, 1993;Løes et al, 2002). During epithelial folding morphogenesis at the cap and bell stages, the nerve fibers form a plexus in the mesenchymal dental follicle region, which surrounds the enamel organ and dental papilla.…”

Immunohistochemical expression of CD56 in dog (Canis familiaris) odontogenesis

“…12 It is therefore crucial to examine the tissue of origin to elucidate the staining patterns observed in the associated tumours. To the best of our knowledge, there are currently four studies where CD56 expression was studied in developing mouse teeth [13][14][15][16] while another two studies evaluated the CD56 expression in human impacted third molars. 17,18 In the latter two cases the tooth crown was already formed and CD56 expression was only investigated in the ectomesenchymal cells of the dental follicle and third molar pad.…”