Epithelial–mesenchymal interactions induce enamel matrix proteins and proteases in the epithelial cells of the rests of Malassez in vitro

Abstract

Epithelial-mesenchymal interactions influence morphogenesis and cell differentiation in periodontal tissue regeneration. The current study examined the expression of amelogenin, ameloblastin, matrix metallopeptidase-20 (MMP-20), and kallikrein-4 (KLK-4) and their effects on the interactions between the epithelial cells of Malassez and periodontal ligament fibroblasts. Explants of human periodontal ligament tissues produced outgrowths containing both the epithelial cells of Malassez and periodontal ligament fibroblasts after incubation in a modified serum-free medium. Both the epithelial cells and fibroblasts were co-cultured in the same dish. The distribution and expression of all four factors were evaluated using immunohistochemistry, in-situ hybridization and RT-PCR analysis. The epithelial cells of Malassez were cultured separately and were used as the control. Immunohistochemical analysis revealed weak expression of amelogenin, ameloblastin, MMP-20 and KLK-4 in epithelial cells of Malassez co-cultured with periodontal ligament fibroblasts. in-situ hybridization and RT-PCR confirmed significant mRNA expression of these factors in co-cultured cells compared with control cells. MMP20 mRNA was not expressed in control cells. These results suggest that the epithelial-mesenchymal interactions promote differentiation of human epithelial cells of Malassez and that the induction of enamel matrix proteases facilitates the degradation of enamel matrix proteins.

Wnt3a signaling induces murine dental follicle cells to differentiate into cementoblastic/osteoblastic cells via an osterix‐dependent pathway

“…Cells were used as confluent monolayers for experiments at subculture levels 2–5. We confirmed that these were epithelial cells, without contamination with fibroblasts, by staining with an epithelial cell‐specific marker, cytokeratin, as we have reported previously . All tissue culture reagents were from Invitrogen/Gibco BRL (Carlsbad, CA, USA), if not otherwise indicated.…”

“…Cells were used as confluent monolayers for experiments at subculture levels 3–10. For epithelial rest cells of Malassez , the tissue fragments were cultured in the epithelial medium described above for human gingival epithelial cells. Cells were used as confluent monolayers for experiments at subculture levels 2–5.…”

A Review of the Epithelial Cell Rests of Malassez on the Bicentennial of Their Description

“…72 When ERM cells are cocultured with PDL fibroblasts, protein expression of both cell types is different compared to the proteins expressed by each cell type cultured individually. [73][74][75][76] Such in vitro experiments have helped to elucidate the potential interactions between ERM cells and PDL fibroblasts that are found in close proximity in vivo. In one experiment, porcine ERM cells were cocultured with porcine PDL fibroblasts in special plates designed to physically separate the 2 cell types by a microporous membrane.…”

Phosphorylation Modulates Ameloblastin Self-assembly and Ca2+ Binding

“…AMBN is functional, and is also expressed in adult bone repair (Nakamura et al, 2006; Spahr et al, 2006; Tamburstuen et al, 2010). During tooth development AMBN is induced by epithelial-mesenchymal interactions and expressed in MSC and epithelial cells (Fong et al, 1998; Takahashi et al, 2012) and in the pre-secretory and secretory stages of ameloblasts development (Nanci et al, 1998). Exon 5 and exon 6 knock down experiments in mice did however, not have any observable effects on the pre-secretory stages of ameloblasts development (Wazen et al, 2009).…”