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Journal of Dental Research Dec 2021The WNT/β-catenin signaling pathway plays a central role in the biology of the periodontium, yet the function of specific extracellular WNT ligands remains poorly...
The WNT/β-catenin signaling pathway plays a central role in the biology of the periodontium, yet the function of specific extracellular WNT ligands remains poorly understood. By using a inducible transgenic mouse model targeting -expressing alveolar osteoblasts, odontoblasts, and cementoblasts, we demonstrate that the WNT ligand WNT1 is a strong promoter of cementum and alveolar bone formation in vivo. We induced expression for 1, 3, or 9 wk in Wnt1Tg mice and analyzed them at the age of 6 wk and 12 wk. Micro-computed tomography (CT) analyses of the mandibles revealed a 1.8-fold increased bone volume after 1 and 3 wk of expression and a 3-fold increased bone volume after 9 wk of expression compared to controls. In addition, the alveolar ridges were higher in Wnt1Tg mice as compared to controls. Nondecalcified histology demonstrated increased acellular cementum thickness and cellular cementum volume after 3 and 9 wk of expression. However, 9 wk of expression was also associated with periodontal breakdown and ectopic mineralization of the pulp. The composition of this ectopic matrix was comparable to those of cellular cementum as demonstrated by quantitative backscattered electron imaging and immunohistochemistry for noncollagenous proteins. Our analyses of 52-wk-old mice after 9 wk of expression revealed that expression affects mandibular bone and growing incisors but not molar teeth, indicating that influences only growing tissues. To further investigate the effect of on cementoblasts, we stably transfected the cementoblast cell line (OCCM-30) with a vector expressing -HA and performed proliferation as well as differentiation experiments. These experiments demonstrated that promotes proliferation but not differentiation of cementoblasts. Taken together, our findings identify, for the first time, as a critical regulator of alveolar bone and cementum formation, as well as provide important insights for harnessing the WNT signal pathway in regenerative dentistry.
Topics: Animals; Cementogenesis; Dental Cementum; Mice; Osteogenesis; Periodontal Ligament; X-Ray Microtomography
PubMed: 34009051
DOI: 10.1177/00220345211012386 -
Scientific Reports Apr 2021Periodontal ligament (PDL) possesses a stem/progenitor population to maintain the homeostasis of periodontal tissue. However, transcription factors that regulate this...
Periodontal ligament (PDL) possesses a stem/progenitor population to maintain the homeostasis of periodontal tissue. However, transcription factors that regulate this population have not yet been identified. Thus, we aimed to identify a molecule related to the osteogenic differentiation of PDL progenitors using a single cell-based strategy in this study. We first devised a new protocol to isolate PDL cells from the surface of adult murine molars and established 35 new single cell-derived clones from the PDL explant. Among these clones, six clones with high (high clones, n = 3) and low (low clones, n = 3) osteogenic potential were selected. Despite a clear difference in the osteogenic potential of these clones, no significant differences in their cell morphology, progenitor cell marker expression, alkaline phosphatase activity, proliferation rate, and differentiation-related gene and protein expression were observed. RNA-seq analysis of these clones revealed that Z-DNA binding protein-1 (Zbp1) was significantly expressed in the high osteogenic clones, indicating that Zbp1 could be a possible marker and regulator of the osteogenic differentiation of PDL progenitor cells. Zbp1-positive cells were distributed sparsely throughout the PDL. In vitro Zbp1 expression in the PDL clones remained at a high level during osteogenic differentiation. The CRISPR/Cas9 mediated Zbp1 knockout in the high clones resulted in a delay in cell differentiation. On the other hand, Zbp1 overexpression in the low clones promoted cell differentiation. These findings suggested that Zbp1 marked the PDL progenitors with high osteogenic potential and promoted their osteogenic differentiation. Clarifying the mechanism of differentiation of PDL cells by Zbp1 and other factors in future studies will facilitate a better understanding of periodontal tissue homeostasis and repair, possibly leading to the development of novel therapeutic measures.
Topics: Animals; CRISPR-Cas Systems; Cell Differentiation; Clone Cells; Humans; Mesenchymal Stem Cells; Mice; Osteogenesis; Periodontal Ligament; Periodontium; RNA-Binding Proteins; RNA-Seq; Stem Cells
PubMed: 33824390
DOI: 10.1038/s41598-021-87016-1 -
Experimental Cell Research Jul 2020Mineralization disorders with a broad range of etiological factors represent a huge challenge in dental diagnosis and therapy. Hypophosphatasia (HPP) belongs to the rare...
Mineralization disorders with a broad range of etiological factors represent a huge challenge in dental diagnosis and therapy. Hypophosphatasia (HPP) belongs to the rare diseases affecting predominantly mineralized tissues, bones and teeth, and occurs due to mutations in the ALPL gene, which encodes tissue-nonspecific alkaline phosphatase (TNAP). Here we analyzed stem cells from bone marrow (BMSCs), dental pulp (DPSCs) and periodontal ligament (PDLSCs) in the absence and presence of efficient TNAP inhibitors. The differentiation capacity, expression of surface markers, and gene expression patterns of donor-matched dental cells were compared during this in vitro study. Differentiation assays showed efficient osteogenic but low adipogenic differentiation (aD) capacity of PDLSCs and DPSCs. TNAP inhibitor treatment completely abolished the mineralization process during osteogenic differentiation (oD). RNA-seq analysis in PDLSCs, comparing oD with and without TNAP inhibitor levamisole, showed clustered regulation of candidate molecular mechanisms that putatively impaired osteogenesis and mineralization, disequilibrated ECM production and turnover, and propagated inflammation. Combined alteration of cementum formation, mineralization, and elastic attachment of teeth to cementum via elastic fibers may explain dental key problems in HPP. Using this in vitro model of TNAP deficiency in DPSCs and PDLSCs, we provide novel putative target areas for research on molecular cues for specific dental problems in HPP.
Topics: Adolescent; Adult; Antirheumatic Agents; Biomarkers; Case-Control Studies; Cell Differentiation; Cells, Cultured; Dental Pulp; Female; Humans; Hypophosphatasia; Inflammation; Levamisole; Male; Mesenchymal Stem Cells; Osteogenesis; Periodontal Ligament; RNA-Seq; Stomatognathic Diseases; Transcriptome; Young Adult
PubMed: 32333908
DOI: 10.1016/j.yexcr.2020.112026 -
Odontology Jul 2019The epithelial rests of Malassez (ERMs) might represent a valuable source of oral epithelial cells with stem cell properties. The purpose of this study was to isolate...
The epithelial rests of Malassez (ERMs) might represent a valuable source of oral epithelial cells with stem cell properties. The purpose of this study was to isolate and characterize cells derived from human ERM, and compare them with cells derived from matched normal oral mucosa (NOM). Matched tissue specimens of the periodontal ligament of extracted tooth and NOM were collected. Cells were isolated in culture, then characterized by immunohistochemistry and flow cytometry for expression of pancytokeratin, ESA, PDGFRB, CD31 and CD44. 3D organotypic cultures were constructed by growing epithelial cells on top of fibroblast-populated collagen gels. Both ERM and NOM-isolated cells expressed the markers of epithelial lineage (ESA and pancytokeratin), and to some extent PDGFR, an indicator of a more mesenchymal phenotype, but not the endothelial cell marker CD31. Cells with epithelial morphology were isolated from periodontium of cervical, middle and apical parts of the root, but contained a significantly lower percentage of ESA and pancytokeratin-positive cells than when isolating cells from NOM (p < 0.001). ERM cells expressed a significantly higher percentage of the stem cell-related molecule CD44 (cervical 92.93 ± 0.25%, middle 93.8 ± 0.26%, apical 94.36 ± 0.41%) than cells isolated from NOM (27.8 ± 1.47%, p < 0.001). When grown in 3D organotypic cultures and in collagen gels, ERM cells formed a less differentiated epithelium than NOM cells, but expressing pancytokeratin and vimentin. In conclusion, epithelial cells could be isolated from human periodontium and grown in culture; their in vitro characterization indicates that they have a less differentiated phenotype compared with cells derived from normal oral epithelium.
Topics: Cells, Cultured; Epithelial Cells; Fibroblasts; Humans; Periodontal Ligament; Rest
PubMed: 30478679
DOI: 10.1007/s10266-018-0397-7 -
Journal of Dental Research Jun 2019Despite an extensive literature documenting the adaptive changes of bones and ligaments to mechanical forces, our understanding of how tissues actually mount a...
Despite an extensive literature documenting the adaptive changes of bones and ligaments to mechanical forces, our understanding of how tissues actually mount a coordinated response to physical loading is astonishingly inadequate. Here, using finite element (FE) modeling and an in vivo murine model, we demonstrate the stress distributions within the periodontal ligament (PDL) caused by occlusal hyperloading. In direct response, a spatially restricted pattern of apoptosis is triggered in the stressed PDL, the temporal peak of which is coordinated with a spatially restricted burst in PDL cell proliferation. This culminates in increased collagen deposition and a thicker, stiffer PDL that is adapted to its new hyperloading status. Meanwhile, in the adjacent alveolar bone, hyperloading activates bone resorption, the peak of which is followed by a bone formation phase, leading ultimately to an accelerated rate of mineral apposition and an increase in alveolar bone density. All of these adaptive responses are orchestrated by a population of Wnt-responsive stem/progenitor cells residing in the PDL and bone, whose death and revival are ultimately responsible for directly giving rise to new PDL fibers and new bone.
Topics: Alveolar Bone Loss; Animals; Finite Element Analysis; Mice; Periodontal Ligament; Periodontium; Stress, Mechanical; Wnt Proteins
PubMed: 30971171
DOI: 10.1177/0022034519839438 -
The Angle Orthodontist May 2014
Topics: Alveolar Process; Biomechanical Phenomena; Bone Remodeling; Dental Cementum; Humans; Inflammation; Periodontal Ligament; Root Resorption; Terminology as Topic; Tooth Mobility; Tooth Movement Techniques; Tooth Root
PubMed: 24749703
DOI: 10.2319/0003-3219-84.3.568 -
TheScientificWorldJournal 2014Mechanical force loading exerts important effects on the skeleton by controlling bone mass and strength. Several in vivo experimental models evaluating the effects of... (Review)
Review
Mechanical force loading exerts important effects on the skeleton by controlling bone mass and strength. Several in vivo experimental models evaluating the effects of mechanical loading on bone metabolism have been reported. Orthodontic tooth movement is a useful model for understanding the mechanism of bone remodeling induced by mechanical loading. In a mouse model of orthodontic tooth movement, TNF-α was expressed and osteoclasts appeared on the compressed side of the periodontal ligament. In TNF-receptor-deficient mice, there was less tooth movement and osteoclast numbers were lower than in wild-type mice. These results suggest that osteoclast formation and bone resorption caused by loading forces on the periodontal ligament depend on TNF-α. Several cytokines are expressed in the periodontal ligament during orthodontic tooth movement. Studies have found that inflammatory cytokines such as IL-12 and IFN-γ strongly inhibit osteoclast formation and tooth movement. Blocking macrophage colony-stimulating factor by using anti-c-Fms antibody also inhibited osteoclast formation and tooth movement. In this review we describe and discuss the effect of cytokines in the periodontal ligament on osteoclast formation and bone resorption during mechanical force loading.
Topics: Animals; Bone Remodeling; Bone Resorption; Cytokines; Humans; Osteoclasts; Periodontal Ligament; Periodontium; Stress, Mechanical; Tooth Migration
PubMed: 24574904
DOI: 10.1155/2014/617032 -
Frontiers in Endocrinology 2023To observe the elongation of the axial tooth movement in the unopposed rodent molar model with type 1 diabetes mellitus and explore the pathological changes of...
OBJECTIVES
To observe the elongation of the axial tooth movement in the unopposed rodent molar model with type 1 diabetes mellitus and explore the pathological changes of periodontal ligament and alveolar bone, and their correlation with tooth axial movement.
METHODS
The 80 C57BL/6J mice were randomly divided into the streptozotocin(STZ)-injected group (n = 50) and the control group (n = 30). Mice in the streptozotocin(STZ)-injected group were injected intraperitoneal with streptozotocin (STZ), and mice in the control group were given intraperitoneal injection of equal doses of sodium citrate buffer. Thirty mice were randomly selected from the successful models as the T1DM group. The right maxillary molar teeth of mice were extracted under anesthesia, and allowed mandibular molars to super-erupt. Mice were sacrificed at 0, 3, 6,9, and 12 days. Tooth elongation and bone mineral density (BMD) were evaluated by micro-CT analysis(0,and 12 days mice). Conventional HE staining, Masson staining and TRAP staining were used to observe the changes in periodontal tissue(0, 3, 6, 9, and 12 days mice). The expression differences of SPARC, FGF9, BMP4, NOGGIN, and type I collagen were analyzed by RT-qPCR.
RESULTS
After 12 days of tooth extraction, our data showed significant super-eruption of mandibular mouse molars of the two groups. The amount of molar super-eruption in the T1DM group was 0.055mm( ± 0.014mm), and in the control group was 0.157( ± 0.017mm). The elongation of the T1DM mice was less than that of the control mice(<0.001). It was observed that the osteoclasts and BMD increased gradually in both groups over time. Compared with the control group, the collagen arrangement was more disordered, the number of osteoclasts was higher (<0.05), and the increase of bone mineral density was lower(2.180 ± 0.007g/cm vs. 2.204 ± 0.006g/cm, <0.001) in the T1DM group. The relative expression of SPARC, FGF9, BMP4, and type I collagen in the two groups increased with the extension of tooth extraction time while NOGGIN decreased. The relative expression of all of SPARC, FGF9, BMP4, and type I collagen in the T1DM group were significantly lower, and the expression of NOGGIN was higher than that in the control group (<0.05).
CONCLUSION
The axial tooth movement was inhibited in type 1 diabetic mice. The result may be associated with the changes of periodontal ligament osteoclastogenic effects and alveolar bone remodeling regulated by the extracellular matrix and osteogenesis-related factors.
Topics: Mice; Animals; Periodontal Ligament; Diabetes Mellitus, Type 1; Collagen Type I; Diabetes Mellitus, Experimental; Streptozocin; Mice, Inbred C57BL
PubMed: 36755916
DOI: 10.3389/fendo.2023.1098702 -
International Journal of Molecular... Apr 2023Periodontitis is a gingiva disease sustained by microbially associated and host-mediated inflammation that results in the loss of the connective periodontal tissues,... (Review)
Review
Periodontitis is a gingiva disease sustained by microbially associated and host-mediated inflammation that results in the loss of the connective periodontal tissues, including periodontal ligament and alveolar bone. Symptoms include swollen gingiva, tooth loss and, ultimately, ineffective mastication. Clinicians utilize regenerative techniques to rebuild and recover damaged periodontal tissues, especially in advanced periodontitis. Human periodontal ligament stem cells (hPDLSCs) are considered an appealing source of stem cells for regenerative therapy in periodontium. hPDLSCs manifest the main properties of mesenchymal stem cells, including the ability to self-renew and to differentiate in mesodermal cells. Significant progress has been made for clinical application of hPDLSCs; nevertheless, some problems remain, including the small number of cells isolated from each sample. In recent decades, hPDLSC ex vivo expansion and differentiation have been improved by modifying cell culture conditions, especially with the supplementation of cytokines' or growth factors' mix, chemicals, and natural compounds, or by using the decellularized extracellular matrix. Here, we analyzed the changes in stemness properties and differentiation potential of hPDLSCs when culturing in alternative media. In addition, we focused on the possibility of replacing FBS with human emoderivates to minimize the risks of xenoimmunization or zoonotic transmission when cells are expanded for therapeutic purposes.
Topics: Humans; Periodontal Ligament; Osteogenesis; Stem Cells; Cell Differentiation; Cells, Cultured; Periodontitis; Cell Proliferation
PubMed: 37175504
DOI: 10.3390/ijms24097798 -
Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Dec 2018Periostin, a kind of matricellular protein highly expressed in periodontal ligament and periosteum, is an important regulator of the integrity of periodontal ligament... (Review)
Review
Periostin, a kind of matricellular protein highly expressed in periodontal ligament and periosteum, is an important regulator of the integrity of periodontal ligament and periodontitis processes. Periostin has been shown to play a positive role in the recovery of periodontitis. This paper reviews relevant literature about the role of periostin in periodontal tissue and periodontitis.
Topics: Humans; Periodontal Ligament; Periodontitis; Periosteum
PubMed: 30593118
DOI: 10.7518/hxkq.2018.06.019