Regulation of OPG and RANKL expressed by human dental follicle cells in osteoclastogenesis

Abstract

We investigate whether the expression of the receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) in human dental follicle cells (HDFCs) regulated by colony stimulating factor 1 (CSF-1), parathyroid hormone-related protein (PTHrP) and bone morphogenetic protein-2 (BMP-2) contributes to osteoclastogenesis. Adolescent human impacted third mandibular molars were used to separate HDFCs. These cells were incubated with PTHrP (10 ng/ml), CSF-1 (25 ng/ml), or BMP-2 (100 ng/ml) for 0.5, 1, 3, 6 and 12 h. The expression of OPG and RANKL was investigated by immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR). Two co-culture systems and tartrate-resistant acid phosphatase (TRAP) staining were used to examine osteoclast formation. Scanning electron microscopy was utilized for the resorption pit assay. RANKL and OPG were expressed innately in HDFCs. Exogenous PTHrP, CSF-1 and BMP-2 chronologically regulated the expression of RANKL and OPG in HDFCs. PTHrP and CSF-1 had similar regulative patterns leading to the up-regulated expression of RANKL and the down-regulated expression of OPG and opposite for BMP-2. The number of TRAP-positive peripheral blood mononuclear cells (PBMCs) slightly increased in contacted co-culture of HDFCs and PBMCs, whereas secreted OPG from HDFCs inhibited osteoclastogenesis in the transwell co-culture system. Contacted co-culture of HDFCs and PBMCs exhibited small and shallow resorption pits, whereas in the transwell co-culture system, secreted OPG from HDFCs reduced the resorption pits, reflecting the difference in osteoclast production. Collectively, we found a dual action of HDFCs in osteoclastogenesis; moreover, PTHrP, CSF-1 and BMP-2 might influence osteoclastogenesis by regulating the expression of RANKL and OPG in HDFCs.

ClC-7 Deficiency Impairs Tooth Development and Eruption

“…Here we found that DFCs/monocytes co-culture system could induce the monocytes to differentiate into osteoclasts. The co-cultures of human/rat DFCs and osteoclast precursors have been applied in contact or non-contact systems before 33 34 . Due to the inhibition function of OPG secreted by DFC, both systems turned out a lower efficiency of TRAP+ cell formation 33 34 and fewer and shallow resorption pits 33 .…”

“…The co-cultures of human/rat DFCs and osteoclast precursors have been applied in contact or non-contact systems before 33 34 . Due to the inhibition function of OPG secreted by DFC, both systems turned out a lower efficiency of TRAP+ cell formation 33 34 and fewer and shallow resorption pits 33 . Those TRAP+ cells in co-culture of DFC and monocytes only formed few and shallow pits in dentin slices, which might also be foreign body giant cells 35 .…”

Parathyroid hormone‐related peptide (1–34) promotes tooth eruption and inhibits osteogenesis of dental follicle cells during tooth development

“…suggesting that PTHrP may play a role in tooth formation. Moreover, previous studies demonstrated that PTHrP increased the expression level of the osteoclast differentiation factor in DF cells (DFCs; Nakchbandi & Broadus, 2000;Sun et al, 2015). However, the regulation of bone resorption and osteogenic differentiation of DFCs by PTHrP remains unclear.…”

Alveolar bone morphology and remodeling parameters in the sites of congenitally missing teeth. A pilot study

“…9 Runex 2 gene is expressed by the dental follicle which directly affects bone formation by stimulating the differentiation of osteoblasts which normally express RANKL and other regulatory genes 10 . The differentiated osteoblasts from the dental follicle cells express RANKL and OPG which act together as regulatory factors for osteoclast differentiation 11 . Ripamonti added that during tooth development, cementum matrix produces morphogenetic signals capable of inducing bone formation 12 .…”