DKK1 and TNF‐alpha influence osteogenic differentiation of adBMP9‐infected‐rDFCs

Abstract

Objectives Rat dental follicle cells (rDFCs) function as precursor cells of periodontal tissues. Bone morphogenetic protein (BMP9) plays an important role in proliferation and differentiation. Tumour necrosis factor‐alpha (TNF‐alpha) is an important contributor to bone resorption. Wnt canonical pathway can be inhibited by Dickkopf 1 (DKK1). The aim of the study was to enhance the osteogenesis of BMP9 treated rDFCs in an inflammatory environment and elucidate the mechanism. Materials and Methods rDFCs were infected by adenoviruses expressing BMP9 (adBMP9). Expression levels of proteins and genes were measured by Western blotting and qPCR. The effect on osteogenesis was evaluated by measuring the activity of alkaline phosphatase (ALP), observation of Alizarin Red S and haematoxylin and eosin staining. Results TNF‐alpha activated the canonical Wnt pathway and inhibited the non‐canonical pathway. DKK1 suppressed the canonical pathway and promoted the non‐canonical pathway. Addition of TNF‐alpha or DKK1 inhibited BMP9/Smad pathway. However, this inhibition was reduced by the addition of DKK1 with TNF‐alpha. Conclusions DKK1 reduces the inhibitory effects of TNF‐alpha in adBMP9‐infected‐rDFCs, possibly through interaction with the Smad signalling pathway and Wnt pathways. These findings may lead to a novel approach for the treatment of periodontitis‐related alveolar bone defects.

TNF‑α regulates the osteogenic differentiation of bone morphogenetic factor 9 adenovirus‑transduced rat follicle stem cells via Wnt signaling

“…the late dental development stage via cellular migration and differentiation (5-7). adBMP9 acts on cells as an exogenous factor to safely and effectively transfect the target gene into the target cell (8)(9)(10)(11)(12)(13). The present study transfected cells with an adenovirus to construct an adBMP9-transduced rdFc model.…”

“…TnF-α levels were reported to be markedly increased in the gingival crevicular fluid of patients with periodontitis and the expression levels of TnF-α have been closely associated with the severity of periodontitis (29,30). Previous studies have identified that TNF-α suppressed cell osteogenic differentiation (8,21,31,32). it was also discovered that high concentrations of TnF-α suppressed the expression of osteogenesis-related factors, such as alP, ocn and runX2 in mesenchymal stem cells (33,34).…”

“…1B). To determine the effect of TnF-α on adBMP9-induced osteogenic differentiation, rdFcs were transfected with adBMP9 prior to treatment with 10 ng/ml TnF-α, which was selected as the stimulatory concentration for use in the experiments (8). cells were collected 7-and 14-days post-transfection and analyzed via alP staining and alizarin red S staining, respectively.…”

“…Wnt signaling has been discovered to be crucial for BMP9-induced osteogenic differentiation (8,24). adGFP was used in preliminary western blotting experiments as the vector control as a comparison to the effects of adBMP9 (Fig.…”

“…Effect of DKK1 treatment on AdBMP9-induced osteogenic differentiation of rDFCs. dKK1 is an inhibitor of the Wnt/β-catenin signaling pathway (8,23). The present study selected 0.1 and 0.4 µg/ml dKK1 as the stimulatory concentrations to treat the rdFcs with.…”