scholarly journals Autophagy Induces Expression of IL-6 in Human Periodontal Ligament Fibroblasts Under Mechanical Load and Overload and Effects Osteoclastogenesis in vitro

2021 ◽  
Vol 12 ◽  
Author(s):  
Alexandra Mayr ◽  
Jana Marciniak ◽  
Benedikt Eggers ◽  
Kim Blawat ◽  
Jan Wildenhof ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mechanical Stimulation ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Physiological Stress ◽  
Mechanical Load ◽  
Dependent Manner ◽  
Periodontal Ligament Fibroblasts ◽  
Autophagy Inhibitor ◽  
Autophagy Inhibition

Objective: Autophagy is an important cellular adaptation mechanism to mechanical stress. In animal experiments, inhibition of autophagy during orthodontic tooth movement triggered increased expression of inflammation-related genes and decreased bone density. The aim of this study was to investigate how autophagy affects cytokine levels of interleukin 6 (IL-6) in human periodontal ligament (hPDL) fibroblasts under mechanical pressure and the resulting influence on osteoblast communication.Methods: hPDL fibroblasts were subjected to physiologic mechanical load, constant overload, or rapamycin treatment for 16 to 24 h ± autophagy inhibitor 3-MA. Autophagosomes were quantified by flow cytometry. Gene expression of il-6 as well as IL-6 levels in the supernatant were determined with rtPCR and ELISA. To investigate the influence of mechanically-induced autophagy on cell-cell communication, an osteoblast-culture was subjected to supernatant from stimulated hPDL fibroblasts ± soluble IL-6 receptor (sIL-6R). After 24 h, osteoprotegerin (opg) and receptor activator of nuclear factor κB ligand (rankl) gene expressions were detected with rtPCR. Gene expression of a disintegrin and metalloproteinases (adam) 10 and 17 in stimulated hPDL fibroblasts was examined via rtPCR.Results: Autophagy was induced by biomechanical stress in hPDL fibroblasts in a dose-dependent manner. Mechanical load and overload increased IL-6 expression at gene and protein level. Autophagy inhibition further enhanced the effects of mechanical stimulation on IL-6 expression. Mechanical stimulation of hPDL fibroblasts downregulated adam10 and adam17 expressions. Inhibition of autophagy had stimulus-intensity depending effects: autophagy inhibition alone or additional application of physiological stress enhanced adam10 and adam17 expressions, whereas mechanical overload had adverse effects. Osteoblasts showed significantly reduced opg expression in the presence of supernatant derived of hPDL fibroblasts treated with autophagy inhibitor and sIL-6R.Conclusion: IL-6 levels were increased in response to pressure in hPDL fibroblasts, which was further enhanced by autophagy inhibition. This caused a decrease in opg expression in osteoblasts. This may serve as an explanatory model for accelerated tooth movement observed under autophagy inhibition, but may also represent a risk factor for uncontrolled bone loss.

scholarly journals In Vitro Compression Model for Orthodontic Tooth Movement Modulates Human Periodontal Ligament Fibroblast Proliferation, Apoptosis and Cell Cycle

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 932
Author(s):  
Julia Brockhaus ◽  
Rogerio B. Craveiro ◽  
Irma Azraq ◽  
Christian Niederau ◽  
Sarah K. Schröder ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Periodontal Ligament ◽  
Environmental Changes ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Compressive Force ◽  
Periodontal Ligament Fibroblasts ◽  
Human Periodontal Ligament Fibroblasts

Human Periodontal Ligament Fibroblasts (hPDLF), as part of the periodontal apparatus, modulate inflammation, regeneration and bone remodeling. Interferences are clinically manifested as attachment loss, tooth loosening and root resorption. During orthodontic tooth movement (OTM), remodeling and adaptation of the periodontium is required in order to enable tooth movement. hPDLF involvement in the early phase-OTM compression side was investigated for a 72-h period through a well-studied in vitro model. Changes in the morphology, cell proliferation and cell death were analyzed. Specific markers of the cell cycle were investigated by RT-qPCR and Western blot. The study showed that the morphology of hPDLF changes towards more unstructured, unsorted filaments under mechanical compression. The total cell numbers were significantly reduced with a higher cell death rate over the whole observation period. hPDLF started to recover to pretreatment conditions after 48 h. Furthermore, key molecules involved in the cell cycle were significantly reduced under compressive force at the gene expression and protein levels. These findings revealed important information for a better understanding of the preservation and remodeling processes within the periodontium through Periodontal Ligament Fibroblasts during orthodontic tooth movement. OTM initially decelerates the hPDLF cell cycle and proliferation. After adapting to environmental changes, human Periodontal Ligament Fibroblasts can regain homeostasis of the periodontium, affecting its reorganization.

scholarly journals Myeloid HIF1α Is Involved in the Extent of Orthodontically Induced Tooth Movement

Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 796
Author(s):  
Christian Kirschneck ◽  
Nadine Straßmair ◽  
Fabian Cieplik ◽  
Eva Paddenberg ◽  
Jonathan Jantsch ◽  
...  
Keyword(s):  
Bone Density ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Hypoxia Inducible Factor ◽  
Myeloid Cells ◽  
Orthodontic Tooth Movement ◽  
Periodontal Ligament Fibroblasts ◽  
Expression Of Genes ◽  
Periodontal Bone Loss

During orthodontic tooth movement, transcription factor hypoxia-inducible factor 1α (HIF1α) is stabilised in the periodontal ligament. While HIF1α in periodontal ligament fibroblasts can be stabilised by mechanical compression, in macrophages pressure application alone is not sufficient to stabilise HIF1α. The present study was conducted to investigate the role of myeloid HIF1α during orthodontic tooth movement. Orthodontic tooth movement was performed in wildtype and Hif1αΔmyel mice lacking HIF1α expression in myeloid cells. Subsequently, µCT images were obtained to determine periodontal bone loss, extent of orthodontic tooth movement and bone density. RNA was isolated from the periodontal ligament of the control side and the orthodontically treated side, and the expression of genes involved in bone remodelling was investigated. The extent of tooth movement was increased in Hif1αΔmyel mice. This may be due to the lower bone density of the Hif1αΔmyel mice. Deletion of myeloid Hif1α was associated with increased expression of Ctsk and Acp5, while both Rankl and its decoy receptor Opg were increased. HIF1α from myeloid cells thus appears to play a regulatory role in orthodontic tooth movement.

scholarly journals The role of 25-hydroxyvitamin-D3 and vitamin D receptor gene in human periodontal ligament fibroblasts as response to orthodontic compressive strain: an in vitro study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Erika Calvano Küchler ◽  
Agnes Schröder ◽  
Vinicius Broska Teodoro ◽  
Ute Nazet ◽  
Rafaela Scariot ◽  
...  
Keyword(s):  
Gene Expression ◽  
Vitamin D ◽  
Single Nucleotide Polymorphisms ◽  
Periodontal Ligament ◽  
Compressive Strain ◽  
Nucleotide Polymorphisms ◽  
Periodontal Ligament Fibroblasts ◽  
Single Nucleotide ◽  
Cox 2

Abstract Background This study aimed to investigate, if different physiological concentrations of vitamin D (25(OH)D3) and single nucleotide polymorphisms in vitamin D receptor (VDR) gene have an impact on gene expression in human periodontal ligament (hPDL) fibroblasts induced by simulated orthodontic compressive strain. Methods A pool of hPDL fibroblasts was treated in absence or presence of 25(OH)D3 in 3 different concentrations (10, 40 and 60 ng/ml). In order to evaluate the role of single nucleotide polymorphisms in the VDR gene, hPDL fibroblasts from 9 patients were used and treated in absence or presence of 40 ng/ml 25(OH)D3. Each experiment was performed with and without simulated orthodontic compressive strain. Real-time PCR was used for gene expression and allelic discrimination analysis. Relative expression of dehydrocholesterol reductase (DHCR7), Sec23 homolog A, amidohydrolase domain containing 1 (AMDHD1), vitamin D 25-hydroxylase (CYP2R1), Hydroxyvitamin D-1-α hydroxylase, receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin (OPG), cyclooxygenase-2 (COX-2) and interleukin-6 (IL6) was assessed. Three single nucleotide polymorphisms in VDR were genotyped. Parametric or non-parametric tests were used with an alpha of 5%. Results RANKL, RANKL:OPG ratio, COX-2, IL-6, DHCR7, CYP2R1 and AMDHD1 were differentially expressed during simulated orthodontic compressive strain (p < 0.05). The RANKL:OPG ratio was downregulated by all concentrations (10 ng/ml, 40 ng/ml and 60 ng/ml) of 25(OH)D3 (mean = 0.96 ± 0.68, mean = 1.61 ± 0.66 and mean = 1.86 ± 0.78, respectively) in comparison to the control (mean 2.58 ± 1.16) (p < 0.05). CYP2R1 gene expression was statistically modulated by the different 25(OH)D3 concentrations applied (p = 0.008). Samples from individuals carrying the GG genotype in rs739837 presented lower VDR mRNA expression and samples from individuals carrying the CC genotype in rs7975232 presented higher VDR mRNA expression (p < 0.05). Conclusions Simulated orthodontic compressive strain and physiological concentrations of 25(OH)D3 seem to regulate the expression of orthodontic tooth movement and vitamin-D-related genes in periodontal ligament fibroblasts in the context of orthodontic compressive strain. Our study also suggests that single nucleotide polymorphisms in the VDR gene regulate VDR expression in periodontal ligament fibroblasts in the context of orthodontic compressive strain.

scholarly journals Role and Regulation of Mechanotransductive HIF-1α Stabilisation in Periodontal Ligament Fibroblasts

2020 ◽  
Vol 21 (24) ◽  
pp. 9530
Author(s):  
Christian Kirschneck ◽  
Magdalena Thuy ◽  
Alexandra Leikam ◽  
Svenja Memmert ◽  
James Deschner ◽  
...  
Keyword(s):  
Periodontal Ligament ◽  
Tensile Strain ◽  
Tooth Movement ◽  
Compressive Strain ◽  
Mechanical Strain ◽  
Hypoxia Inducible Factor ◽  
Orthodontic Tooth Movement ◽  
Prostaglandin Synthesis ◽  
Vegf Expression ◽  
Periodontal Ligament Fibroblasts

Orthodontic tooth movement (OTM) creates compressive and tensile strain in the periodontal ligament, causing circulation disorders. Hypoxia-inducible factor 1α (HIF-1α) has been shown to be primarily stabilised by compression, but not hypoxia in periodontal ligament fibroblasts (PDLF) during mechanical strain, which are key regulators of OTM. This study aimed to elucidate the role of heparan sulfate integrin interaction and downstream kinase phosphorylation for HIF-1α stabilisation under compressive and tensile strain and to which extent downstream synthesis of VEGF and prostaglandins is HIF-1α-dependent in a model of simulated OTM in PDLF. PDLF were subjected to compressive or tensile strain for 48 h. In various setups HIF-1α was experimentally stabilised (DMOG) or destabilised (YC-1) and mechanotransduction was inhibited by surfen and genistein. We found that HIF-1α was not stabilised by tensile, but rather by compressive strain. HIF-1α stabilisation had an inductive effect on prostaglandin and VEGF synthesis. As expected, HIF-1α destabilisation reduced VEGF expression, whereas prostaglandin synthesis was increased. Inhibition of integrin mechanotransduction via surfen or genistein prevented stabilisation of HIF-1α. A decrease in VEGF expression was observed, but not in prostaglandin synthesis. Stabilisation of HIF-1α via integrin mechanotransduction and downstream phosphorylation of kinases seems to be essential for the induction of VEGF, but not prostaglandin synthesis by PDLF during compressive (but not tensile) orthodontic strain.

Expression of MMP-8 and MMP-13 Genes in the Periodontal Ligament during Tooth Movement in Rats

2003 ◽  
Vol 82 (8) ◽  
pp. 646-651 ◽  
Author(s):  
I. Takahashi ◽  
M. Nishimura ◽  
K. Onodera ◽  
J.-W. Bae ◽  
H. Mitani ◽  
...  
Keyword(s):  
Gene Expression ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Polymerase Chain Reaction Analysis ◽  
Tension And Compression ◽  
Polymerase Chain

Periodontal ligament tissue is remodeled on both the tension and compression sides of moving teeth during orthodontic tooth movement. The present study was designed to clarify the hypothesis that the expression of MMP-8 and MMP-13 mRNA is promoted during the remodeling of periodontal ligament tissue in orthodontic tooth movement. We used the in situ hybridization method and semi-quantitative reverse-transcription/polymerase chain-reaction analysis to elucidate the gene expression of MMP-8 and MMP-13 mRNA. Expression of MMP-8 and MMP-13 mRNA transiently increased on both the compression and tension sides during active tooth movement in vivo. The gene expression of MMP-8 and MMP-13 was induced by tension, while compression indirectly promoted the gene expression of MMP-8 and MMP-13 through soluble factors in vitro. Thus, we concluded that the expression of MMP-8 and MMP-13 is differentially regulated by tension and compression, and plays an important role in the remodeling of the periodontal ligament.

scholarly journals Compression and hypoxia play independent roles while having combinative effects in the osteoclastogenesis induced by periodontal ligament cells

2015 ◽  
Vol 86 (1) ◽  
pp. 66-73 ◽  
Author(s):  
Mei Le Li ◽  
Jianru Yi ◽  
Yan Yang ◽  
Xuan Zhang ◽  
Wei Zheng ◽  
...  
Keyword(s):  
Gene Expression ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Thin Sheet ◽  
Orthodontic Tooth Movement ◽  
Compressive Force ◽  
Periodontal Ligament Cells ◽  
Tartrate Resistant Acid Phosphatase ◽  
Hypoxia Group ◽  
Polymerase Chain

ABSTRACT Objective:  To investigate the isolated and combined effects of compression and hypoxia on the osteoclastogenesis induced by periodontal ligament cells (PDLCs). Materials and Methods:  A periodontal ligament tissue model (PDLtm) was established by 3-D culturing human PDLCs on a thin sheet of poly lactic-co-glycolic acid scaffold. The PDLtm was treated with hypoxia and/or compression for 6, 24, or 72 hours. After that, a real-time polymerase chain reaction was used for gene expression analysis. The conditioned media were used for the coculture of osteoblast and osteoclast (OC) precursors; tartrate-resistant acid phosphatase staining was done to examine OC formation. Results:  Either compression or hypoxia alone significantly up-regulated the gene expression of pro-osteoclastogenic cytokines in the PDLtm and enhanced osteoclastogenesis in the cocultures, and the combination of the two had significantly stronger effects than either stimulation alone. In addition, comparing the two stimulants, we found that the osteoclastogenic property of the PDLCs peaked earlier (at 6 hours) in the compression group than in the hypoxia group (at 24 hours). Conclusions:  Both compressive force and hypoxia may take part in initiating osteoclastogenesis in orthodontic tooth movement and may have combinatory effects, which could update our concepts of the mechanisms involved in the initiation of bone resorption on the pressure side of the tooth in question.

Sign in / Sign up

Export Citation Format

Share Document