CD8+ T cells mediate the regenerative PTH effect in hPDL cells via Wnt10b signaling

Abstract

It was the aim of the present investigation to examine whether the stimulating effect of parathyroid hormone (PTH) on human periodontal ligament (hPDL) cell proliferation and differentiation would be enhanced by hPDL/T-cell interaction involving Wnt10b signaling as a mediating pathway. hPDL cells were cultured from healthy premolar tissues of three adolescent orthodontic patients and exposed to PTH(1-34) in monocultures or co-cultures with CD8 T cells. At harvest, proliferation, alkaline phosphatase-specific activity (ALP), and osteocalcin production were determined by immunofluorescence cytochemistry, real-time PCR, biochemical assay, and ELISA. Wnt10b signaling was analyzed by the use of a specific WNT10b neutralizing antibody. PTH(1-34) stimulation of T cells significantly increased Wnt10b expression and production. Wnt10b exposure of hPDL cells enhanced proliferation and differentiation. PDL cells co-cultured with T cells showed a Wnt10b-dependent regulation of proliferation and differentiation parameters. The addition of a Wnt10b-neutralizing Ab to the co-culture medium resulted in a significant inhibition of the PTH(1-34) effect on proliferation, ALP-specific activity, and osteocalcin protein expression. Our findings provide novel insight into the mechanism of action of PTH on hPDL cells and establish the interplay of T cells and hPDL cells via the Wnt10b pathway as a modulating factor for the anabolic properties of the hormone in periodontal regeneration.

Sodium‐chloride‐induced effects on the expression profile of human periodontal ligament fibroblasts with focus on simulated orthodontic tooth movement

“…Expression of ALPL can be stimulated by OPG and promote pre‐osteoblast maturation from mesenchymal stem cells . Periodontal ligament fibroblasts show structural and functional similarities to osteoblasts, which are mainly involved in regenerative bone formation, but also in osteoclastogenesis via their ability to express RANKL . Stimulation of PDLF with NaCl significantly increased expression of the ALPL gene and secretion of the ALPL protein, both with and without simulated orthodontic compressive strain, possibly hinting at a bone‐forming effect of high NaCl concentrations on PDLFs.…”

Valid gene expression normalization by RT-qPCR in studies on hPDL fibroblasts with focus on orthodontic tooth movement and periodontitis

“…Since sequences of these commercially available primers are often not published for corroboration, other problems such as secondary structure formation of primers and amplicons at annealing might be present as well, which is why we chose to exclude these genes and primers in our principal analysis. Furthermore the frequently used reference genes 18S-rRNA (RNA18S5) 8 , POLR2A 15 – 17 , 50 and GAPDH 13 , 14 also showed limited expression stability. Thus the usage of these common reference genes should be reconsidered in future gene expression studies on hPDL fibroblasts.…”

Comparative assessment of mouse models for experimental orthodontic tooth movement

“…Induction of orthodontic tooth movement (OTM) by applying mechanical forces to teeth with orthodontic intra- and extraoral appliances requires a coordinated tissue adaptation in the surrounding alveolar bone and periodontal ligament (PDL), a connective tissue, which connects teeth to their bony sockets 1 . Cells present in the bone and PDL, such as osteoblasts, osteoclasts and osteocytes, as well as fibroblasts and cells of the immune system such as macrophages and T cells 2 , 3 respond to mechanical forces and changes in the local environment 1 . Their response affects the mass and morphology of the surrounding bone 4 , 5 and triggers a sterile inflammatory reaction at the cellular level leading to increased bone remodelling and turnover 1 , 6 .…”