scholarly journals Long Non-coding RNA FER1L4 Mediates the Autophagy of Periodontal Ligament Stem Cells Under Orthodontic Compressive Force via AKT/FOXO3 Pathway

2021 ◽  
Vol 9 ◽  
Author(s):  
Yiping Huang ◽  
Hao Liu ◽  
Runzhi Guo ◽  
Yineng Han ◽  
Yuhui Yang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Compressive Force ◽  
Tissue Remodeling ◽  
Mechanical Force ◽  
Periodontal Tissue ◽  
Periodontal Ligament Stem Cells ◽  
Periodontal Tissue Remodeling

Orthodontic tooth movement is achieved by periodontal tissue remodeling triggered by mechanical force. It is essential to investigate the reaction of periodontal ligament stem cells (PDLSCs) for improving orthodontic therapeutic approaches. Autophagy is an endogenous defense mechanism to prevent mechanical damage of environmental change. Long non-coding RNAs (lncRNAs) are key regulators in gene regulation, but their roles are still largely uncharacterized in the reaction of PDLSCs during orthodontic tooth movement. In this study, we showed that autophagy was significantly induced in PDLSCs under compressive force, as revealed by the markers of autophagy, microtubule-associated protein light chain 3 (LC3) II/I and Beclin1, and the formation of autophagosomes. After the application of compressive force, lncRNA FER1L4 was strongly upregulated. Overexpression of FER1L4 increased the formation of autophagosome and autolysosomes in PDLSCs, while knockdown of FER1L4 reversed the autophagic activity induced by mechanical force. In mechanism, FER1L4 inhibited the phosphorylation of protein kinase B (AKT) and subsequently increased the nuclear translocation of forkhead box O3 (FOXO3) and thus mediated autophagic cascades under compressive strain. In mouse model, the expression of Lc3 as well as Fer1l4 was increased in the pressure side of periodontal ligament during tooth movement. These findings suggest a novel mechanism of autophagy regulation by lncRNA during periodontal tissue remodeling of orthodontic treatment.

scholarly journals Force-Induced Autophagy in Periodontal Ligament Stem Cells Modulates M1 Macrophage Polarization via AKT Signaling

2021 ◽  
Vol 9 ◽  
Author(s):  
Nan Jiang ◽  
Danqing He ◽  
Yushi Ma ◽  
Junxiang Su ◽  
Xiaowen Wu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Remodeling ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Macrophage Polarization ◽  
Akt Signaling ◽  
Mechanical Force ◽  
Akt Signaling Pathway ◽  
Periodontal Ligament Stem Cells ◽  
M1 Macrophage

Autophagy, a lysosomal degradation pathway, serves as a protective cellular mechanism in maintaining cell and tissue homeostasis under mechanical stimulation. As the mechanosensitive cells, periodontal ligament stem cells (PDLSCs) play an important role in the force-induced inflammatory bone remodeling and tooth movement process. However, whether and how autophagy in PDLSCs influences the inflammatory bone remodeling process under mechanical force stimuli is still unknown. In this study, we found that mechanical force stimuli increased the expression of the autophagy protein LC3, the number of M1 macrophages and osteoclasts, as well as the ratio of M1/M2 macrophages in the compression side of the periodontal ligament in vivo. These biological changes induced by mechanical force were repressed by the application of an autophagy inhibitor 3-methyladenine. Moreover, autophagy was activated in the force-loaded PDLSCs, and force-stimulated PDLSC autophagy further induced M1 macrophage polarization in vitro. The macrophage polarization could be partially blocked by the administration of autophagy inhibitor 3-methyladenine or enhanced by the administration of autophagy activator rapamycin in PDLSCs. Mechanistically, force-induced PDLSC autophagy promoted M1 macrophage polarization via the inhibition of the AKT signaling pathway. These data suggest a novel mechanism that force-stimulated PDLSC autophagy steers macrophages into the M1 phenotype via the AKT signaling pathway, which contributes to the inflammatory bone remodeling and tooth movement process.

scholarly journals Biomechanical Interfaces of Corticotomies on Periodontal Tissue Remodeling during Orthodontic Tooth Movement

Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 1
Author(s):  
Ruojing Liu ◽  
Li Huang ◽  
Xiaoyue Xiao ◽  
Yuzhe Guan ◽  
Yukun Jiang ◽  
...  
Keyword(s):  
Alveolar Bone ◽  
Tooth Movement ◽  
Root Resorption ◽  
Orthodontic Tooth Movement ◽  
Tissue Remodeling ◽  
Sham Operation ◽  
Periodontal Tissue ◽  
Wnt Signal Pathway ◽  
Post Surgery ◽  
Periodontal Tissue Remodeling

Corticotomy is an effective approach in accelerating orthodontic tooth movement (OTM) in clinical treatment. Corticotomy causes regional acceleratory phenomenon (RAP) in the alveolar bone of surgical sites. However, the molecular mechanism of RAP after corticotomy remains unclear. Herein, we established a mouse model to study the biomechanical interfaces of corticotomy-assisted OTM and to investigate the histological responses and underlying cellular mechanism. A total of 144 male C57BL/6 mice were randomly assigned into four groups: corticotomy alone (Corti), sham operation (Sham), corticotomy with tooth movement (Corti + TM), and sham operation with tooth movement (Sham + TM). Nickel–titanium orthodontic springs were applied to trigger tooth movement. Mice were sacrificed on Post-Surgery Day (PSD) 3, 7, 14, 21, and 28 for radiographic, histological, immunohistochemical, and molecular biological analyses. The results reveal that corticotomy significantly promoted alveolar bone turnover and periodontal tissue remodeling. During orthodontic tooth movement, corticotomy significantly promoted osteogenic and proliferative activity, accelerated tooth movement, and eliminated root resorption by upregulating Wnt signal pathway.

scholarly journals N-acetylcysteine promotes osteogenic differentiation in periodontal ligament stem cells under cyclic mechanical stretch

2021 ◽  
Author(s):  
Xun Xi ◽  
Zixuan Li ◽  
Yi Zhao ◽  
Hong Liu ◽  
Shuai Chen ◽  
...  
Keyword(s):  
Stem Cells ◽  
Osteogenic Differentiation ◽  
Periodontal Ligament ◽  
Alveolar Bone ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Mechanical Stretch ◽  
Micro Ct ◽  
Periodontal Ligament Stem Cells ◽  
Ct System

Abstract Background Biomechanical forces are vital for the regulation of skeletal tissue. Mechanical stretch plays a vital role in osteogenic differentiation of periodontal ligament stem cells (PDLSCs) during orthodontic treatment. Cyclic mechanical stretch may trigger the up-regulated production of reactive oxygen species (ROS). ROS has a critical effect on bone cell function and the pathophysiology of bone diseases. N-acetylcysteine (NAC), a ROS scavenger, possesses powerful antioxidant capacity. The aim of this study was to determine the role of ROS and NAC in PDLSCs during osteogenic differentiation under cyclic mechanical stretch. We further investigated that the therapeutic potential of NAC to improve the changes of the microstructure of alveolar bone during orthodontic tooth movement in rats by micro-CT system. Methods The expression of COL1 (collagen type I), RUNX2 (runt-related transcription factor 2) and OPN (osteopontin) by qRT-PCR and Western blot experiments, and alkaline phosphatase (ALP) staining as well as ALP activity tests were used to examine osteogenic differentiation tendency of PDLSCs subjected to cyclic mechanical stretch of 10% and 0.5Hz deformation induced by the Flexcell tension system. ROS production in PDLSCs were measured under cyclic mechanical stretch by Flow Cytometry. The levels of reduced glutathione (GSH), oxidized GSH (GSSG) and the GSH/GSSG ratio with or without NAC treatment were analyzed. And we evaluated the changes of the microstructure of alveolar bone during orthodontic tooth movement in rats employing micro-CT system. Results NAC treatment could promote the osteogenic differentiation of PDLSCs under cyclic mechanical stretch. Down-regulated ROS generation and the up-regulated level of GSH and the ratio of GSH/GSSG in PDLSCs treated with NAC were observed in response to cyclic mechanical stretch. NAC improved the microstructure of alveolar bone, including BV/TV (bone volume/total volume), Tb.Th (trabecular thickness), Tb.Sp (trabecular separation) and SMI (microstructure model index), during orthodontic tooth movement in rats. Conclusion These results revealed that NAC might be a potential therapeutic approach for the remodeling of the alveolar bone during orthodontic tooth movement.

scholarly journals Mechanobiology of Periodontal Ligament Stem Cells in Orthodontic Tooth Movement

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Huaming Huang ◽  
Ruili Yang ◽  
Yan-heng Zhou
Keyword(s):  
Stem Cells ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Critical Role ◽  
Orthodontic Tooth Movement ◽  
Periodontal Ligament Stem Cells ◽  
Orthodontic Force ◽  
Applied Forces

Periodontal ligament stem cells (PDLSCs) possess self-renewal, multilineage differentiation, and immunomodulatory properties. They play a crucial role in maintaining periodontal homeostasis and also participated in orthodontic tooth movement (OTM). Various studies have applied controlled mechanical stimulation to PDLSCs and investigated the effects of orthodontic force on PDLSCs. Physical stimuli can regulate the proliferation and differentiation of PDLSCs. During the past decade, a variety of studies has demonstrated that applied forces can activate different signaling pathways in PDLSCs, including MAPK, TGF-β/Smad, and Wnt/β-catenin pathways. Besides, recent advances have highlighted the critical role of orthodontic force in PDLSC fate through mediators, such as IL-11, CTHRC1, miR-21, and H2S. This perspective review critically discusses the PDLSC fate to physical forcein vitroand orthodontic forcein vivo, as well as the underlying molecular mechanism involved in OTM.

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 EZH2 reduction is an essential mechanoresponse for the maintenance of super-enhancer polarization against compressive stress in human periodontal ligament stem cells

2020 ◽  
Vol 11 (9) ◽  
Author(s):  
Qian Li ◽  
Xiwen Sun ◽  
Yunyi Tang ◽  
Yanan Qu ◽  
Yanheng Zhou ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mechanical Stress ◽  
Periodontal Ligament ◽  
Compressive Force ◽  
Mechanical Stimuli ◽  
Periodontal Ligament Stem Cells ◽  
Super Enhancer ◽  
Ezh2 Expression ◽  
A Genome ◽  
Temporal Dimensions

Abstract Despite the ubiquitous mechanical cues at both spatial and temporal dimensions, cell identities and functions are largely immune to the everchanging mechanical stimuli. To understand the molecular basis of this epigenetic stability, we interrogated compressive force-elicited transcriptomic changes in mesenchymal stem cells purified from human periodontal ligament (PDLSCs), and identified H3K27me3 and E2F signatures populated within upregulated and weakly downregulated genes, respectively. Consistently, expressions of several E2F family transcription factors and EZH2, as core methyltransferase for H3K27me3, decreased in response to mechanical stress, which were attributed to force-induced redistribution of RB from nucleoplasm to lamina. Importantly, although epigenomic analysis on H3K27me3 landscape only demonstrated correlating changes at one group of mechanoresponsive genes, we observed a genome-wide destabilization of super-enhancers along with aberrant EZH2 retention. These super-enhancers were tightly bounded by H3K27me3 domain on one side and exhibited attenuating H3K27ac deposition and flattening H3K27ac peaks along with compensated EZH2 expression after force exposure, analogous to increased H3K27ac entropy or decreased H3K27ac polarization. Interference of force-induced EZH2 reduction could drive actin filaments dependent spatial overlap between EZH2 and super-enhancers and functionally compromise the multipotency of PDLSC following mechanical stress. These findings together unveil a specific contribution of EZH2 reduction for the maintenance of super-enhancer stability and cell identity in mechanoresponse.

scholarly journals Osteoclastic effects of mBMMSCs under compressive pressure during orthodontic tooth movement

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jing Wang ◽  
Delong Jiao ◽  
Xiaofeng Huang ◽  
Yuxing Bai
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Normal Saline ◽  
Periodontal Ligament ◽  
Alveolar Bone ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Mouse Bone Marrow ◽  
Micro Ct ◽  
Tail Vein

Abstract Background During orthodontic tooth movement (OTM), alveolar bone remodelling is closely related to mechanical force. It is unclear whether stem cells can affect osteoclastogenesis to promote OTM. This study aimed to investigate the role of mouse bone marrow mesenchymal stem cells (mBMMSCs) under compression load in OTM. Methods A mouse OTM model was established, and GFP-labelled mBMMSCs and normal saline were injected into different groups of mice by tail vein injection. OTM distance was measured using tissue specimens and micro-computed tomography (micro-CT). The locations of mBMMSCs were traced using GFP immunohistochemistry. Haematoxylin-eosin staining, tartrate-resistant acid phosphate (TRAP) staining and immunohistochemistry of Runx2 and lipoprotein lipase were used to assess changes in the periodontal ligament during OTM. mBMMSCs under compression were co-cultured with mouse bone marrow-derived macrophages (mBMMs), and the gene expression levels of Rankl, Mmp-9, TRAP, Ctsk, Alp, Runx2, Ocn and Osterix were determined by RT-PCR. Results Ten days after mBMMSCs were injected into the tail vein of mice, the OTM distance increased from 176 (normal saline) to 298.4 μm, as determined by tissue specimen observation, and 174.2 to 302.6 μm, as determined by micro-CT metrological analysis. GFP-labelled mBMMSCs were mostly located on the compressed side of the periodontal ligament. Compared to the saline group, the number of osteoclasts in the alveolar bone increased significantly (P < 0.01) on the compressed side in the mBMMSC group. Three days after mBMMSC injection, the number of Runx2-GFP double-positive cells on the tension side was significantly higher than that on the compression side. After applying compressive force on the mBMMSCs in vitro for 2 days, RANKL expression was significantly higher than in the non-compression cells, but expression of Alp, Runx2, Ocn and Osterix was significantly decreased (P < 0.05). The numbers of osteoclasts differentiated in response to mBMMs co-cultured with mBMMSCs under pressure load and expression of osteoclast differentiation marker genes (Mmp-9, TRAP and Ctsk) were significantly higher than those in mBMMs stimulated by M-CSF alone (P < 0.05). Conclusions mBMMSCs are not only recruited to the compressed side of the periodontal ligament but can also promote osteoclastogenesis by expressing Rankl, improving the efficiency of OTM.

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.

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