Expression of odontogenic ameloblast-associated protein in the dental follicle and its role in osteogenic differentiation of dental follicle stem cells

Abstract

Objective Odontogenic Ameloblast-Associated Protein (ODAM) is encoded by a secretory calcium-binding phosphoprotein cluster gene, which generally plays an important role for mineralization. Dental follicle (DF) is essential in regulating bone formation for tooth eruption. This study aims to reveal ODAM expression in the DFs of developing and erupting molars, and to determine the possible role of ODAM. Design DFs were collected from human third molars and rat mandibular molars for gene expression assessment and for establishment of cell cultures. RT-PCR and western blot were conducted to determine ODAM expression. Over- or silencing expression of ODAM in the dental follicle stem cells (DFSCs) was done by transfecting the cells with ODAM plasmid or siRNA to evaluate ODAM effects on osteogenesis. Results Rat DFs weakly expressed ODAM at early-postnatal days, but a chronological increment of ODAM expression from days 1 to 11 was observed. Differences in expression of ODAM were seen in the human DFs of different individuals. In vitro, ODAM was expressed in DFSCs, but almost no expression in DF-derived fibroblast-like cells. Forcing the DFSCs to overexpress ODAM accelerated osteogenesis, whereas continuously silencing the ODAM in the DFSCs reduced osteogenesis only at 2 weeks of osteogenic induction. Conclusions ODAM is differentially expressed in the DFs of different age molars. Its expression is coincident with the increased bone formation of tooth crypt during tooth eruption in rat DFs. Increase of ODAM expression may accelerate osteogenic differentiation of DFSCs. Thus, ODAM expression in the DF may regulate bone formation for timely tooth eruption.

Effects of rhBMP-2 on Bone Formation Capacity of Rat Dental Stem/Progenitor Cells from Dental Follicle and Alveolar Bone Marrow

“…Wise et al [34] reported that nonstem DFCs would be gained when cultured in MEM and 10% Gibco newborn calf serum with antibiotics, indicating that DFC cultures derived from this condition are fibroblast-like cells [34] and do not possess the capability of differentiation [37]. Yao et al [37,38] reported that primary cultured cell populations derived from dental tissue contained stem cells when cultured in medium consisting of a-MEM plus 20% FBS and proper antibiotics, indicating that our isolated primary DFCs and ABM-MSCs derived from this condition contained stem cells.…”

Glutamine Metabolism Is Essential for Stemness of Bone Marrow Mesenchymal Stem Cells and Bone Homeostasis

“…Previous studies supported that glutamine metabolism as a regulatory node participated in many biological processes, including vessel formation, cancer progress, and immune regulation [14–16]. Recently, glutamine in bone homeostasis gained increasing concentration in mediating the proliferation, osteoblast, and adipocyte differentiation, immunological features of cell BMSCs [17].…”

Dental Follicle Cells: Roles in Development and Beyond

“…Ameloblast-associated protein (OADM) related to mineralization expressed on DFCs in a time-dependent pattern. The gradually increased OADM expression in the early stage of differentiation accelerated osteogenesis to make a normal eruption, and the missing OADM did not influence bone density but resulted in a postponed tooth eruption [54, 55]. Cleidocranial dysplasia (CCD) patients are characterized by delayed tooth eruption due to runt-related transcription factor 2 ( Runx2 ) mutation, DFCs-CCD patients displayed significantly lower osteogenic, osteoclast-inductive and matrix-degrading capacities, mechanistically contacted with disturbed RANK/RANKL/OPG signaling and decreased expression of matrix metalloproteinase 9 (MMP9) and MMP2 [56–58].…”

“…The level of EGR1 was elevated after osteogenic differentiation of DFCs and in turn it regulated the expression of DLX3 and BMP2 to mediate osteogenic differentiation positively [96]. Fractional odontogenic matrix protein such as dentin matrix protein 1 (DMP1) and odontogenic ameloblast-associated protein (ODAM) have been identified to correlate positively with the osteogenic capability of DFCs, which suggested the complex microenvironment in different time and space for DFC differentiation in tooth development [54, 97].…”