Secretion of CSF‐1 and its inhibition in rat dental follicle cells, implications for tooth eruption

Abstract

Tooth eruption requires the presence of a dental follicle around the unerupted tooth. Before the onset of eruption there is an influx of mononuclear cells into the follicle which, in turn, form osteoclasts that erode the alveolar bone. Eruption can be accelerated by the injection of colony-stimulating factor-one (CSF-1), a molecule that is maximally transcribed and translated in the dental follicle cells at the time of peak influx of mononuclear cells into the follicle of the rat first mandibular molar. To determine if the rat dental follicle cells secrete the CSF-1 needed for these cellular events, conditioned medium was collected from cultures of these cells. Using as a bioassay, a cell line (m-NFS 60) that is responsive to CSF-1 for growth, it was shown that conditioned medium from the follicle cells stimulated growth of the m-NFS 60 cells by almost 33% over the controls. Western blots confirmed that CSF-1 was secreted into the medium. Treating the dental follicle cells with an antisense oligodeoxynucleotide probe against CSF-1 reduced the amount of CSF-1 produced. These results demonstrate that CSF-1 is secreted by the dental follicle cells and that the production of CSF-1 can be reduced with an antisense probe. This secretion by the dental follicle might recruit mononuclear cells into the follicle to initiate tooth eruption.

Regulation of secretion of osteoprotegerin in rat dental follicle cells

“…As seen by the results discussed above, both CSF‐1 and PTHrP reduce the secretion of OPG in vitro and can do so at the same concentration that maximally reduces the expression of OPG in vitro (4). CSF‐1 is secreted by the dental follicle cells (9, 18) and, as such, could have an autocrine effect on the cells to inhibit OPG secretion. Because the CSF‐1 gene is maximally expressed in the follicle of the first mandibular molar at day 3 postnatally in the rat, it is probable that maximal secretion of CSF‐1 occurs to contribute to the reduction in OPG expression also seen at day 3 postnatally (4).…”

Bone Morphogenetic Protein 2 Induces Dental Follicle Cells to Differentiate Toward a Cementoblast/Osteoblast Phenotype

“…Cells within the dental follicle region, a loose connective tissue surrounding the developing tooth, play a critical role in the process of tooth eruption (17–22) . In addition, substantial evidence exists indicating that follicle cells are progenitors of periodontal cells including cementoblasts, PDL fibroblasts, and alveolar osteoblasts (23–25) .…”

HSP25 Affects the Proliferation and Differentiation of Rat Dental Follicle Cells

“…Mononuclear and osteoclast formation initiate at day 3 postnatally in the rat molar . Highly-expressed molecules, such as CSF-1, EGF, MCP-1 and NF-КB, have all been proven significant in the ostoclastogenesis process during eruption (Lin et al, 1996;Grier et al, 1998;Que et al, 1998;Que et al, 1999). However, relatively few in vivo studies have been carried out on the role of those molecules in osteogenesis during eruption.…”

“…It was reported that vascular endothelial growth factor (VEGF), dexamethasone/insulin, bone morphogenetic protein 2 (BMP2) and bone morphogenetic protein 7 (BMP7) can promote cementoblast/osteoblast differentiation of DFCs (Zhao et al, 2002;Morsczeck et al, 2005;Chen et al, 2007;Kémoun et al, 2007). In tooth eruption, cytokines such as colony-stimulating factor 1 (CSF-1) and its receptor, interleukin-1 (IL-1) and its receptor, endothelial growth factor (EGF), monocyte chemoattractant protein 1 (MCP-1) and nuclear factor-κB (NF-κB) were noted for their involvement in the dental follicle, in which they combine to form a complicated tooth eruption network system (Lin et al, 1996;Wise et al, 1997;Xu et al, 1998;Que et al, 1998;Grier et al, 1998;Que et al, 1999;Gu et al, 2003).…”