1
|
Abstract
Cementum is a mineralized tissue covering the tooth root that functions in tooth attachment and posteruptive adjustment of tooth position. During formation of the apically located cellular cementum, some cementoblasts become embedded in the cementoid matrix and become cementocytes. As apparently terminally differentiated cells embedded in a mineralized extracellular matrix, cementocytes are part of a select group of specialized cells, also including osteocytes, hypertrophic chondrocytes, and odontoblasts. The differentiation and potential function(s) of cementocytes are virtually unknown, and the question may be posed whether the cementocyte is a dynamic actor in cementum in comparable fashion with the osteocyte in the skeleton, responding to changing tooth functions and endocrine signals and actively directing local cementum metabolism. This review summarizes the literature with regard to cementocytes, comparing them to their closest "cousins," the osteocytes, where insights gained from osteocyte studies serve to inform the critical examination of cementocytes. The review identifies important unanswered questions about these cells regarding their origins, differentiation, morphology and lacuno-canalicular system, selective markers, and potential functions.
Collapse
Affiliation(s)
- N Zhao
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA Department of Orthodontics, Shanghai Key Laboratory of Stomatology, Shanghai No. 9 Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - B L Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - L F Bonewald
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| |
Collapse
|
2
|
Zhao N, Nociti FH, Duan P, Prideaux M, Zhao H, Foster BL, Somerman MJ, Bonewald LF. Isolation and Functional Analysis of an Immortalized Murine Cementocyte Cell Line, IDG-CM6. J Bone Miner Res 2016; 31:430-442. [PMID: 26274352 PMCID: PMC4827449 DOI: 10.1002/jbmr.2690] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 08/08/2015] [Accepted: 08/12/2015] [Indexed: 12/30/2022]
Abstract
The dental cementum covering the tooth root is similar to bone in several respects but remains poorly understood in terms of development and differentiation of cementoblasts, as well as the potential function(s) of cementocytes residing in the cellular cementum. It is not known if the cementocyte is a dynamic actor in cementum metabolism, comparable to the osteocyte in the bone. Cementocytes exhibit irregular spacing and lacunar shape, with fewer canalicular connections compared with osteocytes. Immunohistochemistry and quantitative PCR (qPCR) revealed that the in vivo expression profile of cementocytes paralleled that of osteocytes, including expression of dentin matrix protein 1 (Dmp1/DMP1), Sost/sclerostin, E11/gp38/podoplanin, Tnfrsf11b (osteoprotegerin [OPG]), and Tnfsf11 (receptor activator of NF-κB ligand [RANKL]). We used the Immortomouse(+/-); Dmp1-GFP(+/-) mice to isolate cementocytes as Dmp1-expressing cells followed by immortalization using the interferon (IFN)-γ-inducible promoter driving expression of a thermolabile large T antigen to create the first immortalized line of cementocytes, IDG-CM6. This cell line reproduced the expression profile of cementocytes observed in vivo, including alkaline phosphatase activity and mineralization. IDG-CM6 cells expressed higher levels of Tnfrsf11b and lower levels of Tnfsf11 compared with IDG-SW3 osteocytes, and under fluid flow shear stress, IDG-CM6 cells significantly increased OPG while decreasing RANKL, leading to a significantly increased OPG/RANKL ratio, which would inhibit osteoclast activation. These studies indicate similarities yet potentially important differences in the function of cementocytes compared with osteocytes and support cementocytes as mechanically responsive cells.
Collapse
Affiliation(s)
- Ning Zhao
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA.,Department of Orthodontics, Shanghai Key Laboratory of Stomatology, Shanghai No. 9 Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Francisco H Nociti
- Laboratory of Oral Connective Tissue Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA.,Department of Prosthodontics and Periodontics, Division of Periodontics, School of Dentistry at Piracicaba, Piracicaba, Sao Paulo, Brazil
| | - Peipei Duan
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA.,Department of Orthodontics, State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, Chengdu, China
| | - Matthew Prideaux
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA.,Bone Cell Biology Group, Centre for Orthopaedic & Trauma Research, University of Adelaide, Adelaide, Australia
| | - Hong Zhao
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Brian L Foster
- Laboratory of Oral Connective Tissue Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA.,Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Martha J Somerman
- Laboratory of Oral Connective Tissue Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Lynda F Bonewald
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| |
Collapse
|
3
|
Effects of TGF-β1 on OPG/RANKL expression of cementoblasts and osteoblasts are similar without stress but different with mechanical compressive stress. ScientificWorldJournal 2015; 2015:718180. [PMID: 25685846 PMCID: PMC4312653 DOI: 10.1155/2015/718180] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 12/06/2014] [Accepted: 12/06/2014] [Indexed: 02/05/2023] Open
Abstract
Introduction. This study aimed to explore the effects of TGF-β1 on regulating activities of cementoblasts and osteoblasts with or without stress. Material and Methods. Human recombinant TGF-β1 was added with different doses. Immunohistochemical test of osteoprotegerin (OPG)/receptor activator of nuclear factor-kappaB ligand (RANKL) and Alizarin Red-S staining were conducted. Mechanical compressive stress was obtained by increasing the pressure of gaseous phase. OPG/RANKL expression was detected in both cells through quantitative real-time PCR. Results. Similar significant differences (P < 0.05) existed in OPG/RANKL change with increasing concentration of TGF-β1 without mechanical stress for cementoblasts and osteoblasts. However, under 3 h stress, OPG increased and RANKL decreased significantly (P < 0.01) but with similar OPG/RANKL change. Moreover, under 24 h stress, OPG change exhibited no difference (P > 0.05), but RANKL decreased significantly (P < 0.01) at 10 and 100 ng/mL TGF-β1 in cementoblasts. In osteoblasts, OPG increased significantly (P < 0.01) at 10 and 100 ng/mL, whereas RANKL decreased with statistical difference (P < 0.05) at 1 and 10 ng/mL. Conclusions. The effects of TGF-β1 on OPG/RANKL expression of cementoblasts and osteoblasts are similar even without mechanical stress. However, these effects are different under mechanical compressive stress.
Collapse
|
4
|
Tsuchiya S, Tsuchiya M, Nishioka T, Suzuki O, Sasano Y, Igarashi K. Physiological distal drift in rat molars contributes to acellular cementum formation. Anat Rec (Hoboken) 2013; 296:1255-63. [PMID: 23775928 DOI: 10.1002/ar.22731] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 04/15/2013] [Indexed: 12/15/2022]
Abstract
Occlusal forces may induce the physiological teeth migration in humans, but there is little direct evidence. Rat molars are known to migrate distally during aging, possibly caused by occlusal forces. The purpose of this study was to determine if a reduction in occlusion would decrease teeth migration and affect associated periodontal structures such as cementum. To reduce occlusal forces, the right upper first molar (M1) in juvenile rats was extracted. The transition of the position of upper second molar (M2) and formation of M2 cementum was followed during aging. From the cephalometric analyses, upper M2 was located more anterior compared with the original position with aging after M1 extraction. Associated with this "slowing-down" of the physiological drift, cementum thickness on distal surface, but not on mesial surface, of M2 root was significantly increased. The accumulation of alizarin red as vital stain indicative of calcification, was observed in the distal cementum of M2 root only on the side of M1 extraction. Extraction of M1 that results in less functional loading, distinctly attenuates the physiological drift only in the upper dentition. The decreased physiological drift appears to activate acellular cementum formation only on distal surface of M2 root, perhaps due to reduced mechanical stress associated with the attenuated distal drift. In conclusion, the physiological distal drift in rat molars appears to be largely driven by the occlusal force and also affects the formation of acellular cementum. These findings provide additional direct evidence for an important role of occlusal forces in tooth migration.
Collapse
Affiliation(s)
- Shinobu Tsuchiya
- Division of Oral Dysfunction Science, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | | | | | | | | | | |
Collapse
|
5
|
Monnouchi S, Maeda H, Fujii S, Tomokiyo A, Kono K, Akamine A. The Roles of Angiotensin II in Stretched Periodontal Ligament Cells. J Dent Res 2011; 90:181-5. [DOI: 10.1177/0022034510382118] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The loading caused by occlusion and mastication plays an important role in maintaining periodontal ligament (PDL) tissues. We hypothesized that a loading magnitude would be involved in the production of biological factors that function in the maintenance of PDL tissues. Here, we identified up-regulated gene expressions of transforming growth factor-β1 (TGF-β1), alkaline phosphatase (ALP), and angiotensinogen in human PDL fibroblastic cells (HPLFs) that were exposed to 8% stretch loading. Immunolocalization of angiotensin I/II (Ang I/II), which was converted from angiotensinogen, was detected in rat PDL tissues. HPLFs that were stimulated by Ang II also increased their gene expressions of TGF-β1 and ALP. Furthermore, the antagonist for Ang II type 2 receptor, rather than for type 1, significantly inhibited gene expressions induced by the stretch loading. Analysis of these data suggests that Ang II mediates the loading signal in stretched HPLFs to induce expressions of TGF-β1 and ALP.
Collapse
Affiliation(s)
- S. Monnouchi
- Division of Oral Rehabilitation, Department of Endodontology and Operative Dentistry, Faculty of Dental Science, Kyushu University
| | - H. Maeda
- Department of Endodontology, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - S. Fujii
- Department of Endodontology, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - A. Tomokiyo
- Division of Oral Rehabilitation, Department of Endodontology and Operative Dentistry, Faculty of Dental Science, Kyushu University
| | - K. Kono
- Division of Oral Rehabilitation, Department of Endodontology and Operative Dentistry, Faculty of Dental Science, Kyushu University
| | - A. Akamine
- Division of Oral Rehabilitation, Department of Endodontology and Operative Dentistry, Faculty of Dental Science, Kyushu University
- Department of Endodontology, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| |
Collapse
|
6
|
Bosshardt DD, Sculean A, Windisch P, Pjetursson BE, Lang NP. Effects of enamel matrix proteins on tissue formation along the roots of human teeth. J Periodontal Res 2005; 40:158-67. [PMID: 15733151 DOI: 10.1111/j.1600-0765.2005.00785.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Enamel matrix-derived proteins (EMD) are thought to trigger the formation of acellular extrinsic fibre cementum (AEFC), while other reports indicate that EMD may have osteogenic potential. The aim of the present study was to characterize the tissues developing on the root surface following application of EMD. METHODS Twelve human periodontitis-affected teeth, scheduled for extraction, were treated with EMD. Two to 6 weeks later, the teeth were extracted, demineralized and processed for embedding in acrylic and epoxy resins. New tissue formation was analysed by light and transmission electron microscopy. RESULTS New tissue formation on the root was observed in the notch and on both scaled and unscaled root surfaces distant of the notch area in six defects. The newly formed tissues on the root were thick, collagenous, devoid of extrinsic fibres, and had an irregular surface contour. The presence of electron-dense, organic material in the collagenous matrix indicated at least partial mineralization. Embedded cells were numerous and the cells on the matrix surface were very large in size. Abundant rough endoplasmic reticulum and a prominent Golgi complex were evident. The presence of a split between the treated root surfaces and the newly formed tissue was a common observation, as was the presence of bacteria and host cells in the interfacial gap. CONCLUSION Following treatment with EMD, a bone-like tissue resembling cellular intrinsic fibre cementum may develop on the root surfaces, instead of AEFC. Furthermore, EMD may both induce de novo formation of a mineralized connective tissue on scaled root surfaces and stimulate matrix deposition on old native cementum. Interfacial bonding appeared to be weak after 6 weeks of healing.
Collapse
Affiliation(s)
- Dieter D Bosshardt
- Department of Periodontology and Fixed Prosthodontics, School of Dental Medicine, University of Berne, Berne, Switzerland.
| | | | | | | | | |
Collapse
|
7
|
Hashimoto F, Kobayashi Y, Kobayashi ET, Sakai E, Kobayashi K, Shibata M, Kato Y, Sakai H. Expression and localization of MGP in rat tooth cementum. Arch Oral Biol 2001; 46:585-92. [PMID: 11369313 DOI: 10.1016/s0003-9969(01)00022-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Tooth cementum, a calcified hard tissue covering the root surfaces, is an important component connecting the teeth to the collagenous fibres of the periodontal ligament. Although the overall composition of cementum may closely resemble that of bone, each part has not been fully characterized. Here, the localization of the matrix gamma-carboxyglutamic acid (Gla) protein (MGP), one of the major Gla-containing proteins in the body, in cementum was investigated using immunohistochemistry and in situ hybridization. (1) Strong MGP antigenicity was observed in the acellular cementum, but was only moderate in the cellular cementum; (2) polygonal periodontal ligament cells facing the acellular cementum and the uncalcified cellular cementum expressed MGP mRNA, indicating that these cells produced MGP and deposited it on the cementum; (3) MGP accumulated at the junction between the uncalcified and calcified cellular cementum; and (4) the distribution pattern of MGP antigenicity resembled that of osteopontin. As one function of MGP could be as a negative regulator for mineral apposition, the expression of MGP in the cells adjacent to the cementum may be important to prevent hyperapposition of minerals.
Collapse
Affiliation(s)
- F Hashimoto
- Department of Orthodontics, School of Dentistry, Nagasaki University, 1-7-1 Sakamoto, 852-8588, Nagasaki, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
8
|
|
9
|
Kagayama M, Sasano Y, Akita H. Time and position-specific expression of glycosaminoglycans in rat molar cementum related to physiological tooth movement. J Periodontal Res 1995; 30:285-9. [PMID: 7562326 DOI: 10.1111/j.1600-0765.1995.tb02135.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The role of glycosaminoglycans (GAGs) and proteoglycans during cementogenesis is not known. In this study, we have analysed the temporal and spacial expression of GAGs in the cellular cementum of 10-30 weeks old rats, immunohistochemically using monoclonal antibodies 2B6 and 3B3, specific for chondroitin 4-sulfate/dermatan sulfate and chondroitin 6-sulfate, respectively. Both 2B6- and 3B3-epitopes were expressed at similar position and time in the rat cellular cementum. Two types of cellular cementum were identified; GAG-positive and GAG-negative cementum. The former corresponded to the lightly stained and the latter to the darkly stained cementum in sections stained with haematoxylin and eosin. The GAG-positive cementum was seen at the distal side of dentine surface and appeared most thick at, middle of the apical half roots, whereas the other parts of the cementum were the GAG-negative. Distribution of GAG-positive cementum showed changes with age of animals. In 10-15 week old rats, the GAG-positive cementum occupied most of the cementum layer, covering a thin layer of the GAG-negative cementum. The cellular cementum of 20-30 week old rats consisted of three layers; GAG-negative, GAG-positive and GAG-negative cementum from dentine to cementum surface, reducing the GAG-positive area. Because our previous study has demonstrated that the lightly stained cementum is uncalcified, the present result suggests a correlation between calcification and contents of GAGs in the cellular cementum. Further, time- and position-specific expression of GAGs indicates their relation to the physiological tooth movement, which has been known in the rat molars.
Collapse
Affiliation(s)
- M Kagayama
- Department of Anatomy, Tohoku University School of Dentistry, Sendai, Japan
| | | | | |
Collapse
|