Expression of UNCL during development of periodontal tissue and response of periodontal ligament fibroblasts to mechanical stress in vivo and in vitro

Genes expressed by human periodontal ligament fibroblasts (HPFs) are likely to be associated with specific functions of the ligament. The aim of this study is to profile genes expressed highly by HPFs. A library (6 × 103 pfu) was constructed, followed by subtraction of HPF cDNAs with human gingival fibroblast (HGF) cDNAs. Reverse-dot hybridization revealed that 33 clones expressed higher levels of specific mRNAs in HPFs than in HGFs. These were mRNAs for known genes, including several associated with maturation and differentiation of cells. None had been reported in PFs. One clone, PDL-29, identified as a COX assembly factor, showed much stronger mRNA expression in HPFs than in HGFs in culture. In rat periodontium, however, PDL-29 mRNA expression was similar in PFs and GFs. These results suggest that HPFs express many previously unreported genes associated with maturation and differentiation, but expression can differ in vitro and in vivo.

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Intermittent Compressive Stress Enhanced Insulin-Like Growth Factor-1 Expression in Human Periodontal Ligament Cells

International Journal of Cell Biology ◽

10.1155/2015/369874 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Jittima Pumklin ◽

Jeeranan Manokawinchoke ◽

Kanokporn Bhalang ◽

Prasit Pavasant

Keyword(s):

Mechanical Stress ◽

Compressive Stress ◽

Periodontal Ligament ◽

Molecular Mechanisms ◽

Treated Group ◽

Periodontal Ligament Cells ◽

Human Periodontal Ligament Cells ◽

Chemical Inhibitors

Mechanical force was shown to promote IGF-1 expression in periodontal ligament both in vitro and in vivo. Though the mechanism of this effect has not yet been proved, here we investigated the molecular mechanism of intermittent mechanical stress on IGF-1 expression. In addition, the role of hypoxia on the intermittent compressive stress on IGF-1 expression was also examined. In this study, human periodontal ligament cells (HPDLs) were stimulated with intermittent mechanical stress for 24 hours. IGF-1 expression was examined by real-time polymerase chain reaction. Chemical inhibitors were used to determine molecular mechanisms of these effects. For hypoxic mimic condition, the CoCl2 supplementation was employed. The results showed that intermittent mechanical stress dramatically increased IGF-1 expression at 24 h. The pretreatment with TGF-β receptor I or TGF-β1 antibody could inhibit the intermittent mechanical stress-induced IGF-1 expression. Moreover, the upregulation of TGF-β1 proteins was detected in intermittent mechanical stress treated group. Correspondingly, the IGF-1 expression was upregulated upon being treated with recombinant human TGF-β1. Further, the hypoxic mimic condition attenuated the intermittent mechanical stress and rhTGF-β1-induced IGF-1 expression. In summary, this study suggests intermittent mechanical stress-induced IGF-1 expression in HPDLs through TGF-β1 and this phenomenon could be inhibited in hypoxic mimic condition.

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α11β1 Integrin-Dependent Regulation of Periodontal Ligament Function in the Erupting Mouse Incisor

Molecular and Cellular Biology ◽

10.1128/mcb.00041-07 ◽

2007 ◽

Vol 27 (12) ◽

pp. 4306-4316 ◽

Cited By ~ 86

Author(s):

Svetlana N. Popova ◽

Malgorzata Barczyk ◽

Carl-Fredrik Tiger ◽

Wouter Beertsen ◽

Paola Zigrino ◽

...

Keyword(s):

Periodontal Ligament ◽

Tooth Movement ◽

Tooth Eruption ◽

Collagen I ◽

Periodontal Ligament Fibroblasts ◽

Primary Defect ◽

Embryonic Fibroblasts ◽

Mouse Incisor

ABSTRACT The fibroblast integrin α11β1 is a key receptor for fibrillar collagens. To study the potential function of α11 in vivo, we generated a null allele of the α11 gene. Integrin α11−/− mice are viable and fertile but display dwarfism with increased mortality, most probably due to severely defective incisors. Mutant incisors are characterized by disorganized periodontal ligaments, whereas molar ligaments appear normal. The primary defect in the incisor ligament leads to halted tooth eruption. α11β1-defective embryonic fibroblasts displayed severe defects in vitro, characterized by (i) greatly reduced cell adhesion and spreading on collagen I, (ii) reduced ability to retract collagen lattices, and (iii) reduced cell proliferation. Analysis of matrix metalloproteinase in vitro and in vivo revealed disturbed MMP13 and MMP14 synthesis in α11−/− cells. We show that α11β1 is the major receptor for collagen I on mouse embryonic fibroblasts and suggest that α11β1 integrin is specifically required on periodontal ligament fibroblasts for cell migration and collagen reorganization to help generate the forces needed for axial tooth movement. Our data show a unique role for α11β1 integrin during tooth eruption.

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Contraction and organization of collagen gels by cells cultured from periodontal ligament, gingiva and bone suggest functional differences between cell types

Journal of Cell Science ◽

10.1242/jcs.50.1.299 ◽

1981 ◽

Vol 50 (1) ◽

pp. 299-314

Author(s):

C.G. Bellows ◽

A.H. Melcher ◽

J.E. Aubin

Keyword(s):

Periodontal Ligament ◽

Cell Types ◽

The Other ◽

Collagen Gels ◽

Collagen Fibres ◽

Periodontal Ligament Fibroblasts ◽

3 Dimensional ◽

Cell Processes

Monkey periodontal ligament fibroblasts (MPLF cells), human gingival fibroblasts (HGF cells), rat embryonic calvaria cells (REC cells), porcine periodontal ligament epithelial cells (PPLE cells) and rat osteosarcoma 17/2 cells (ROS cells) were incorporated into 3-dimensional collagen gels plated in 60 mm Petri dishes in order: first, to measure the capacity of these cell types to contract; second, to investigate cell-collagen and intercellular relationships during contraction; and third, to define the cellular contribution to tissue contraction in an in vitro system. Measurements at times up to 72 h on 3 ml gels containing 5 × 10(5) cells and with a collagen concentration of 1.20 mg/ml showed that MPLF cells contracted the gels at a significantly greater rate (P less than 0.001) than did the other cell types. In addition, contraction started sooner and was of greater extent than with the other cells. HGF cells contracted the gels more rapidly than REC and PPLE cells, while ROS cells caused no contraction. Several stages of gel compaction could be defined: (1) the attachment of cells to collagen; (2) cellular spreading within the collagen fibre matrix; (3) organization and alignment of collagen fibres by cell processes; (4) cell migration; (5) establishment of intercellular contacts; and (6) the development of a cellular reticular arrangement within the gel and the extension of this arrangement into a 3-dimensional, tissue-like, honeycomb network. Electron microscopic observations on 0.1 ml gels containing MPLF cells showed that, in the early contractile phase, numerous cell processes attached to or enclosed collagen fibrils. These processes contained microfilamentous material and few organelles. In compacted gels, the cells contained an increased amount of distended rough endoplasmic reticulum and Golgi membranes. Since MPLF cells have the capacity for vigorous contraction of the collagen gels and since they develop a reticular, 3-dimensional structure in compacted gels that is reminiscent of the relationship of periodontal ligament fibroblasts to collagen fibres in vivo, it is suggested that they could provide the major force necessary for tooth eruption in vivo. This system also provides a well-defined in vitro model to study the sequential stages that occur during contraction processes.

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Effect of Static Compressive Force on Aldehyde Dehydrogenase Activity in Periodontal Ligament Fibroblasts

The Open Dentistry Journal ◽

10.2174/1874210602115010417 ◽

2021 ◽

Vol 15 (1) ◽

pp. 417-423

Author(s):

Fabio Schemann-Miguel ◽

Antonio Carlos Aloise ◽

Silvana Gaiba ◽

Lydia Masako Ferreira

Keyword(s):

Aldehyde Dehydrogenase ◽

Periodontal Ligament ◽

Tooth Movement ◽

Compressive Force ◽

Control Group ◽

Aldh Activity ◽

Periodontal Ligament Fibroblasts ◽

Normal Tissues

Background: The application of static compressive forces to periodontal ligament fibroblasts (PDLFs) in vivo or in vitro has been linked to the expression of biochemical agents and local tissue modifications that could be involved in maintaining homeostasis during orthodontic movement. An approach used for identifying mesenchymal cells, or a subpopulation of progenitor cells in both tumoral and normal tissues, involves determining the activity of aldehyde dehydrogenase (ALDH). However, the role of subpopulations of PDLF-derived undifferentiated cells in maintaining homeostasis during tooth movement remains unclear. Objective: This study aimed at analyzing the effect of applying a static compressive force to PDLFs on the activity of ALDH in these cells. Methods: PDLFs were distributed into two groups: control group (CG), where fibroblasts were not submitted to compression, and experimental group (EG), where fibroblasts were submitted to a static compressive force of 4 g/mm2 for 6 hours. The compressive force was applied directly to the cells using a custom-built device. ALDH activity in the PDLFs was evaluated by a flow cytometry assay. Results: ALDH activity was observed in both groups, but was significantly lower in EG than in CG after the application of a static compressive force in the former. Conclusion: Application of a static compressive force to PDLFs decreased ALDH activity.

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PPARγ-Induced Global H3K27 Acetylation Maintains Osteo/Cementogenic Abilities of Periodontal Ligament Fibroblasts

International Journal of Molecular Sciences ◽

10.3390/ijms22168646 ◽

2021 ◽

Vol 22 (16) ◽

pp. 8646

Author(s):

Hang Yuan ◽

Shigeki Suzuki ◽

Shizu Hirata-Tsuchiya ◽

Akiko Sato ◽

Eiji Nemoto ◽

...

Keyword(s):

Periodontal Ligament ◽

Alveolar Bone ◽

Key Factors ◽

Active Chromatin ◽

Periodontal Ligament Fibroblasts ◽

Chromatin Region ◽

Transcriptional Alterations ◽

Pparγ Agonists

The periodontal ligament is a soft connective tissue embedded between the alveolar bone and cementum, the surface hard tissue of teeth. Periodontal ligament fibroblasts (PDLF) actively express osteo/cementogenic genes, which contribute to periodontal tissue homeostasis. However, the key factors maintaining the osteo/cementogenic abilities of PDLF remain unclear. We herein demonstrated that PPARγ was expressed by in vivo periodontal ligament tissue and its distribution pattern correlated with alkaline phosphate enzyme activity. The knockdown of PPARγ markedly reduced the osteo/cementogenic abilities of PDLF in vitro, whereas PPARγ agonists exerted the opposite effects. PPARγ was required to maintain the acetylation status of H3K9 and H3K27, active chromatin markers, and the supplementation of acetyl-CoA, a donor of histone acetylation, restored PPARγ knockdown-induced decreases in the osteo/cementogenic abilities of PDLF. An RNA-seq/ChIP-seq combined analysis identified four osteogenic transcripts, RUNX2, SULF2, RCAN2, and RGMA, in the PPARγ-dependent active chromatin region marked by H3K27ac. Furthermore, RUNX2-binding sites were selectively enriched in the PPARγ-dependent active chromatin region. Collectively, these results identified PPARγ as the key transcriptional factor maintaining the osteo/cementogenic abilities of PDLF and revealed that global H3K27ac modifications play a role in the comprehensive osteo/cementogenic transcriptional alterations mediated by PPARγ.

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Mesenchymal Stem Cells Acquire Characteristics of Cells in the Periodontal Ligament in vitro

Journal of Dental Research ◽

10.1177/154405910408300106 ◽

2004 ◽

Vol 83 (1) ◽

pp. 27-34 ◽

Cited By ~ 45

Author(s):

P.R. Kramer ◽

S. Nares ◽

S.F. Kramer ◽

D. Grogan ◽

M. Kaiser

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Periodontal Ligament ◽

Bone Sialoprotein ◽

Clinical Applications ◽

Periodontal Ligament Cells ◽

Periodontal Tissue

Mesenchymal stem cells differentiate into multiple types of cells derived from mesenchyme. Periodontal ligament cells are primarily derived from mesenchyme; thus, we expected mesenchymal stem cells to differentiate into periodontal ligament. Using a combination of immunohistochemistry and in situ hybridization on co-cultures of mesenchymal stem cells and periodontal ligament, we observed a significant increase in mesenchymal stem cells’ expression of osteocalcin and osteopontin and a significant decrease in expression of bone sialoprotein, characteristics of periodontal ligament in vivo. Increased osteopontin and osteocalcin and decreased bone sialoprotein expression was detected within 7 days and maintained through 21 days of co-culture. We conclude that contact or factors from periodontal ligament induced mesenchymal stem cells to obtain periodontal-ligament-like characteristics. Importantly, analysis of the data suggests the feasibility of utilizing mesenchymal stem cells in clinical applications for repairing and/or regenerating periodontal tissue.

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

Biomolecules ◽

10.3390/biom11070932 ◽

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.

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Exosomal Vimentin from Adipocyte Progenitors Protects Fibroblasts against Osmotic Stress and Inhibits Apoptosis to Enhance Wound Healing

International Journal of Molecular Sciences ◽

10.3390/ijms22094678 ◽

2021 ◽

Vol 22 (9) ◽

pp. 4678

Author(s):

Sepideh Parvanian ◽

Hualian Zha ◽

Dandan Su ◽

Lifang Xi ◽

Yaming Jiu ◽

...

Keyword(s):

Wound Healing ◽

Osmotic Stress ◽

Mechanical Stress ◽

Impaired Wound Healing ◽

In Vivo Experiments ◽

Adipocyte Progenitors ◽

Osmotic Balance ◽

Induced Apoptosis

Mechanical stress following injury regulates the quality and speed of wound healing. Improper mechanotransduction can lead to impaired wound healing and scar formation. Vimentin intermediate filaments control fibroblasts’ response to mechanical stress and lack of vimentin makes cells significantly vulnerable to environmental stress. We previously reported the involvement of exosomal vimentin in mediating wound healing. Here we performed in vitro and in vivo experiments to explore the effect of wide-type and vimentin knockout exosomes in accelerating wound healing under osmotic stress condition. Our results showed that osmotic stress increases the size and enhances the release of exosomes. Furthermore, our findings revealed that exosomal vimentin enhances wound healing by protecting fibroblasts against osmotic stress and inhibiting stress-induced apoptosis. These data suggest that exosomes could be considered either as a stress modifier to restore the osmotic balance or as a conveyer of stress to induce osmotic stress-driven conditions.

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