scholarly journals Nonuniformity in Periodontal Ligament: Mechanics and Matrix Composition

2020 ◽  
pp. 002203452096245
Author(s):  
B.K. Connizzo ◽  
L. Sun ◽  
N. Lacin ◽  
A. Gendelman ◽  
I. Solomonov ◽  
...  
Keyword(s):  
Periodontal Ligament ◽  
Type I Collagen ◽  
Alveolar Bone ◽  
Tooth Movement ◽  
Critical Role ◽  
3D Structure ◽  
Matrix Composition ◽  
Type I ◽  
Critical Function ◽  
Significant Difference

The periodontal ligament (PDL) plays a critical role in providing immediate response to abrupt high loads during mastication while also facilitating slow remodeling of the alveolar bone. The PDL exceptional functionality is permitted by the unique nonuniform structure of the tissue. Two distinct areas that are critical to PDL function were previously identified: the furcation and the dense collar. Despite their hypothesized functions in tooth movement and maintenance, these 2 regions have not yet been compared within the context of their native environment. Therefore, the objective of this study is to elucidate the extracellular matrix (ECM) structure, composition, and biomechanical function of the furcation and the collar regions while maintaining the 3-dimensional (3D) structure in the murine PDL. We identify significant difference between the collar and furcation regions in both structure and mechanical properties. Specifically, we observed unique longitudinal structures in the dense collar that correlate with type VI collagen and LOX, both of which are associated with increased type I collagen density and tissue stiffness and are therefore proposed to function as scaffolds for tooth stabilization. We also found that the collar region is stiffer than the furcation region and therefore suggest that the dense collar acts as a suspense structure of the tooth within the bone during physiological loading. The furcation region of the PDL contained more proteins associated with reduced stiffness and higher tissue remodeling, as well as a dual mechanical behavior, suggesting a critical function in loads transfer and remodeling of the alveolar bone. In summary, this work unravels the nonuniform nature of the PDL within the 3D structural context and establishes understanding of regional PDL function, which opens new avenues for future studies of remodeling, regeneration, and disease.

Sphingomyelin Phosphodiesterase 3 Enhances Cytodifferentiation of Periodontal Ligament Cells

2016 ◽  
Vol 96 (3) ◽  
pp. 339-346 ◽  
Author(s):  
S. Miyauchi ◽  
J. Kitagaki ◽  
R. Masumoto ◽  
A. Imai ◽  
K. Kobayashi ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Periodontal Ligament ◽  
Type I Collagen ◽  
Alveolar Bone ◽  
Skeletal Development ◽  
Aggressive Periodontitis ◽  
Periodontal Ligament Cells ◽  
Type I ◽  
Phosphodiesterase 3 ◽  
Pdl Cells

Sphingomyelin phosphodiesterase 3 ( Smpd3), which encodes neutral sphingomyelinase 2 (nSMase2), is a key molecule for skeletal development as well as for the cytodifferentiation of odontoblasts and alveolar bone. However, the effects of nSMase2 on the cytodifferentiation of periodontal ligament (PDL) cells are still unclear. In this study, the authors analyzed the effects of Smpd3 on the cytodifferentiation of human PDL (HPDL) cells. The authors found that Smpd3 increases the mRNA expression of calcification-related genes, such as alkaline phosphatase (ALPase), type I collagen, osteopontin, Osterix (Osx), and runt-related transcription factor (Runx)-2 in HPDL cells. In contrast, GW4869, an inhibitor of nSMase2, clearly decreased the mRNA expression of ALPase, type I collagen, and osteocalcin in HPDL cells, suggesting that Smpd3 enhances HPDL cytodifferentiation. Next, the authors used exome sequencing to evaluate the genetic variants of Smpd3 in a Japanese population with aggressive periodontitis (AgP). Among 44 unrelated subjects, the authors identified a single nucleotide polymorphism (SNP), rs145616324, in Smpd3 as a putative genetic variant for AgP among Japanese people. Moreover, Smpd3 harboring this SNP did not increase the sphingomyelinase activity or mRNA expression of ALPase, type I collagen, osteopontin, Osx, or Runx2, suggesting that this SNP inhibits Smpd3 such that it has no effect on the cytodifferentiation of HPDL cells. These data suggest that Smpd3 plays a crucial role in maintaining the homeostasis of PDL tissue.

scholarly journals Mechanosensitive Piezo1 in Periodontal Ligament Cells Promotes Alveolar Bone Remodeling During Orthodontic Tooth Movement

2021 ◽  
Vol 12 ◽  
Author(s):  
Yukun Jiang ◽  
Yuzhe Guan ◽  
Yuanchen Lan ◽  
Shuo Chen ◽  
Tiancheng Li ◽  
...  
Keyword(s):  
Bone Remodeling ◽  
Periodontal Ligament ◽  
Alveolar Bone ◽  
Tooth Movement ◽  
Critical Role ◽  
Orthodontic Tooth Movement ◽  
Chemical Signals ◽  
Periodontal Tissues ◽  
Alveolar Bone Remodeling ◽  
Pdl Cells

Orthodontic tooth movement (OTM) is a process depending on the remodeling of periodontal tissues surrounding the roots. Orthodontic forces trigger the conversion of mechanical stimuli into intercellular chemical signals within periodontal ligament (PDL) cells, activating alveolar bone remodeling, and thereby, initiating OTM. Recently, the mechanosensitive ion channel Piezo1 has been found to play pivotal roles in the different types of human cells by transforming external physical stimuli into intercellular chemical signals. However, the function of Piezo1 during the mechanotransduction process of PDL cells has rarely been reported. Herein, we established a rat OTM model to study the potential role of Piezo1 during the mechanotransduction process of PDL cells and investigate its effects on the tension side of alveolar bone remodeling. A total of 60 male Sprague-Dawley rats were randomly assigned into three groups: the OTM + inhibitor (INH) group, the OTM group, and the control (CON) group. Nickel-titanium orthodontic springs were applied to trigger tooth movement. Mice were sacrificed on days 0, 3, 7, and 14 after orthodontic movement for the radiographic, histological, immunohistochemical, and molecular biological analyses. Our results revealed that the Piezo1 channel was activated by orthodontic force and mainly expressed in the PDL cells during the whole tooth movement period. The activation of the Piezo1 channel was essential for maintaining the rate of orthodontic tooth movement and facilitation of new alveolar bone formation on the tension side. Reduced osteogenesis-associated transcription factors such as Runt-related transcription factor 2 (RUNX2), Osterix (OSX), and receptor activator of nuclear factor-kappa B ligand (RANKL)/osteoprotegerin (OPG) ratio were examined when the function of Piezo1 was inhibited. In summary, Piezo1 plays a critical role in mediating both the osteogenesis and osteoclastic activities on the tension side during OTM.

scholarly journals Comparison of BALP, CTX-I, and IL-4 levels around miniscrew implants during orthodontic tooth movement between two different amounts of force

2019 ◽  
Vol 89 (4) ◽  
pp. 630-636
Author(s):  
Mine Gecgelen Cesur ◽  
V. Ozgen Ozturk ◽  
Beral Afacan ◽  
F. Burcu Sirin ◽  
Afra Alkan ◽  
...  
Keyword(s):  
Type I Collagen ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Interleukin 4 ◽  
Enzyme Linked Immunosorbent Assay ◽  
Type I ◽  
Bone Specific Alkaline Phosphatase ◽  
Time Points ◽  
Significant Difference ◽  
The Right

ABSTRACT Objectives: To evaluate the Interleukin-4 (IL-4), bone-specific alkaline phosphatase (BALP), and C-telopeptide of type I collagen (CTX-I) levels in peri-miniscrew crevicular fluid (PMCF) during orthodontic tooth movement between 75 and 150 g of distalization force. Materials and Methods: Thirty miniscrews were placed bilaterally between the maxillary second premolars and first molars. The right and the left maxillary canines were moved distally using either 75 or 150 g of force. PMCF samples were collected before loading (T0); at 2 hours (T1) and 24 hours (T2) later; and on days 7 (T3), 14 (T4), 21 (T5), 30 (T6), and 90 (T7) after force application. Enzyme-linked immunosorbent assay kits were used to determine BALP, CTX-I, and IL-4 levels. Results: There was no significant difference between the force groups at all time points with respect to BALP, CTX-I, and IL-4 levels (P > .05). There was no significant difference among time points for the two force groups in terms of BALP and IL-4 levels (P > .05). The CTX-I level at T3 was significantly higher than at T0 for both force groups (P < .05). Conclusions: Both 75 g and 150 g of orthodontic force are within optimal force limits, and there is no difference in biochemical markers of bone turnover.

scholarly journals Specific immunohistochemical localization of osteonectin and collagen types I and III in fetal and adult porcine dental tissues.

1985 ◽  
Vol 33 (6) ◽  
pp. 531-540 ◽  
Author(s):  
P S Tung ◽  
C Domenicucci ◽  
S Wasi ◽  
J Sodek
Keyword(s):  
Periodontal Ligament ◽  
Type I Collagen ◽  
Alveolar Bone ◽  
Type Iii Collagen ◽  
Similar Distribution ◽  
Type I ◽  
Collagen Types ◽  
Type Iii ◽  
Dental Tissues ◽  
Strong Staining

Affinity-purified antibodies have been used in combination with the peroxidase-antiperoxidase technique to study the distribution of osteonectin and collagen types I and III in porcine dental tissues. Tissue sections (2 mm thick), including unerupted (fetal) or erupted (adult) teeth, were fixed in periodate-lysine-paraformaldehyde, demineralized in 12% w/v ethylenediaminetetraacetic acid, and after embedding, 6 micron sections were prepared for immunolocalization. Strong staining for osteonectin was observed in dentine of unerupted teeth and in the associated alveolar bone. Light to moderate staining was observed in the dental pulp, stratum intermedium, stellate reticulum, and the reticular elements in the endosteal spaces. In erupted teeth, osteonectin staining in dentine was concentrated around dentinal tubules and the associated alveolar bone stained with variable intensity. Cementum was poorly stained. However, the periodontal ligament and reticular material in the endosteal spaces showed moderate to strong staining. Weaker staining was apparent in the pulp and lamina propria of the gingiva. In comparison, type I collagen showed a similar distribution to osteonectin in both fetal and adult tissues, whereas type III collagen was generally restricted to the periodontal ligament, reticular elements of the endosteal spaces, and Sharpey's fibers in bone and cementum. Both odontoblast and ameloblast layers in fetal tissues stained for osteonectin and type III collagen.

scholarly journals Collagen molecular phenotypic switch between non-neoplastic and neoplastic canine mammary tissues

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Masahiko Terajima ◽  
Yuki Taga ◽  
Becky K. Brisson ◽  
Amy C. Durham ◽  
Kotaro Sato ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Mammary Gland ◽  
Mammary Carcinoma ◽  
Cancer Biology ◽  
Type I Collagen ◽  
Critical Role ◽  
Premature Death ◽  
Mammary Tissue ◽  
Type I ◽  
Cross Links

AbstractIn spite of major advances over the past several decades in diagnosis and treatment, breast cancer remains a global cause of morbidity and premature death for both human and veterinary patients. Due to multiple shared clinicopathological features, dogs provide an excellent model of human breast cancer, thus, a comparative oncology approach may advance our understanding of breast cancer biology and improve patient outcomes. Despite an increasing awareness of the critical role of fibrillar collagens in breast cancer biology, tumor-permissive collagen features are still ill-defined. Here, we characterize the molecular and morphological phenotypes of type I collagen in canine mammary gland tumors. Canine mammary carcinoma samples contained longer collagen fibers as well as a greater population of wider fibers compared to non-neoplastic and adenoma samples. Furthermore, the total number of collagen cross-links enriched in the stable hydroxylysine-aldehyde derived cross-links was significantly increased in neoplastic mammary gland samples compared to non-neoplastic mammary gland tissue. The mass spectrometric analyses of type I collagen revealed that in malignant mammary tumor samples, lysine residues, in particular those in the telopeptides, were markedly over-hydroxylated in comparison to non-neoplastic mammary tissue. The extent of glycosylation of hydroxylysine residues was comparable among the groups. Consistent with these data, expression levels of genes encoding lysyl hydroxylase 2 (LH2) and its molecular chaperone FK506-binding protein 65 were both significantly increased in neoplastic samples. These alterations likely lead to an increase in the LH2-mediated stable collagen cross-links in mammary carcinoma that may promote tumor cell metastasis in these patients.

scholarly journals Autophagy facilitates type I collagen synthesis in periodontal ligament cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomomi Nakamura ◽  
Motozo Yamashita ◽  
Kuniko Ikegami ◽  
Mio Suzuki ◽  
Manabu Yanagita ◽  
...  
Keyword(s):  
Periodontal Ligament ◽  
Collagen Synthesis ◽  
Type I Collagen ◽  
Periodontal Diseases ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Physiological Role ◽  
Type I ◽  
Periodontal Tissue ◽  
Pdl Cells

AbstractAutophagy is a lysosomal protein degradation system in which the cell self-digests its intracellular protein components and organelles. Defects in autophagy contribute to the pathogenesis of age-related chronic diseases, such as myocardial infarction and rheumatoid arthritis, through defects in the extracellular matrix (ECM). However, little is known about autophagy in periodontal diseases characterised by the breakdown of periodontal tissue. Tooth-supportive periodontal ligament (PDL) tissue contains PDL cells that produce various ECM proteins such as collagen to maintain homeostasis in periodontal tissue. In this study, we aimed to clarify the physiological role of autophagy in periodontal tissue. We found that autophagy regulated type I collagen synthesis by elimination of misfolded proteins in human PDL (HPDL) cells. Inhibition of autophagy by E-64d and pepstatin A (PSA) or siATG5 treatment suppressed collagen production in HPDL cells at mRNA and protein levels. Immunoelectron microscopy revealed collagen fragments in autolysosomes. Accumulation of misfolded collagen in HPDL cells was confirmed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis. E-64d and PSA treatment suppressed and rapamycin treatment accelerated the hard tissue-forming ability of HPDL cells. Our findings suggest that autophagy is a crucial regulatory process that facilitates type I collagen synthesis and partly regulates osteoblastic differentiation of PDL cells.

scholarly journals Characterization of porcine osteonectin extracted from foetal calvariae

1988 ◽  
Vol 253 (1) ◽  
pp. 139-151 ◽  
Author(s):  
C Domenicucci ◽  
H A Goldberg ◽  
T Hofmann ◽  
D Isenman ◽  
S Wasi ◽  
...  
Keyword(s):  
Amino Acids ◽  
Secondary Structure ◽  
Type I Collagen ◽  
Culture Shock ◽  
Gel Filtration ◽  
Alpha Helix ◽  
Type I ◽  
Homologous Proteins ◽  
Compact Structure ◽  
Significant Difference

Osteonectin, extracted from foetal porcine calvariae with 0.5 M-EDTA, was purified to homogeneity by using gel filtration and polyanion anion-exchange fast protein liquid chromatography under dissociative conditions without the need of reducing agents. The purified protein migrated with an Mr of 40,300 on SDS/polyacrylamide gels and was similar to bovine osteonectin in both amino acid composition and in its ability to bind to hydroxyapatite in the presence of 4 M-guanidinium hydrochloride (GdmCl). However, unlike the bovine protein, porcine osteonectin did not bind selectively to hydroxyapatite when EDTA tissue extracts were used. In addition, purified porcine osteonectin did not show any apparent affinity for either native or denatured type I collagen, but did bind to serum albumin. Primary sequence analysis revealed an N-terminal alanine residue, with approximately one-half of the subsequent 35 residues identified as small hydrophobic amino acids and one-quarter as acidic amino acids. The only significant difference between the N-terminal sequences of the bovine and porcine proteins was the deletion of the tripeptide Val-Ala-Glu in porcine osteonectin. In contrast with bovine osteonectin, far-u.v.c.d. of porcine osteonectin revealed considerable secondary structure, of which 27% was alpha-helix and 39% was beta-sheet. Cleavage of the molecule with CNBr under non-reducing conditions generated five fragments, of which two major fragments (Mr 27,900 and 12,400) stained blue with Stains All, a reagent that stains sialic-acid-rich proteins/phosphate-containing proteins and/or Ca2+-binding proteins blue while staining other proteins pink. The 12,400-Mr fragment bound 45Ca2+ selectively, indicating a Ca2+-binding site in this part of the molecule. The 27,900-Mr fragment did not bind Ca2+, and since biosynthetic studies with 32PO4(3-) did not show phosphorylation of porcine osteonectin, this fragment is likely to be highly acidic. The incomplete cleavage of the molecule with CNBr and the ability of the molecule to regain its secondary structure after exposure to 7 M-urea are features consistent with the molecule having a compact structure that is stabilized by numerous disulphide bridges. The chemical and binding properties of porcine osteonectin are closely similar to the recently described ‘culture shock’, SPARC and BM-40 proteins, indicating that these are homologous proteins.

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.

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