Expression of Connexin 43 in Rat Mandibular Bone and Periodontal Ligament (PDL) Cells during Experimental Tooth Movement

Su, Mu; Borke, James L.; Donahue, Henry J.; Li, Z.; Warshawsky, Neil; Russell, Charles D.; Lewis, Jill E.

doi:10.1177/00220345970760070501

Cited by 75 publications

(66 citation statements)

References 22 publications

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“…Ubiquitously expressed Cx43 has been identified in primary osteocytes in vivo [123] and MLO-Y4 cells [107]. Cx45 is also expressed in MLO-Y4 cells [124].…”

Section: Osteocytes In Bone Tissuementioning

confidence: 98%

A paradigm shift for bone quality in dentistry: A literature review

Kuroshima

Kaku

Ishimoto

et al. 2017

Journal of Prosthodontic Research

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A B S T R A C TPurpose: The aim of this study was to present the current concept of bone quality based on the proposal by the National Institutes of Health (NIH) and some of the cellular and molecular factors that affect bone quality. Study selection: This is a literature review which focuses on collagen, biological apatite (BAp), and bone cells such as osteoblasts and osteocytes. Results: In dentistry, the term "bone quality" has long been considered to be synonymous with bone mineral density (BMD) based on radiographic and sensible evaluations. In 2000, the NIH proposed the concept of bone quality as "the sum of all characteristics of bone that influence the bone's resistance to fracture," which is completely independent of BMD. The NIH defines bone quality as comprising bone architecture, bone turnover, bone mineralization, and micro-damage accumulation. Moreover, our investigations have demonstrated that BAp, collagen, and bone cells such as osteoblasts and osteocytes play essential roles in controlling the current concept of bone quality in bone around hip and dental implants. Conclusion: The current concept of bone quality is crucial for understanding bone mechanical functions. BAp, collagen and osteocytes are the main factors affecting bone quality. Moreover, mechanical loading dynamically adapts bone quality. Understanding the current concept of bone quality is required in dentistry.

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“…Ubiquitously expressed Cx43 has been identified in primary osteocytes in vivo [123] and MLO-Y4 cells [107]. Cx45 is also expressed in MLO-Y4 cells [124].…”

Section: Osteocytes In Bone Tissuementioning

confidence: 98%

A paradigm shift for bone quality in dentistry: A literature review

Kuroshima

Kaku

Ishimoto

et al. 2017

Journal of Prosthodontic Research

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“…)4ס‬ QRT-PCR for BMP4 mRNA showed a 1.8-fold increase in expression as well as BMP2 (F). stretching in osteogenic cells 4,12,33) and in PDL cells 33) has been investigated. However, whether mechanical stretching induces the activation of Gja1 in ERM remains unknown.…”

Section: ) Effect Of 18gamentioning

confidence: 99%

Epithelial Cell Rests of Malassez Modulate Cell Proliferation, Differentiation and Apoptosis via Gap Junctional Communication under Mechanical Stretching in vitro

Haku¹,

Muramatsu²,

Hara³

et al. 2011

Bull. Tokyo Dent. Coll.

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Epithelial cell rests of Malassez (ERM) are involved in the maintenance and homeostasis of the periodontal ligament. The objective of this study was to investigate the effect of mechanical stretching on cell growth, cell death and differentiation in the ERM. Cultured porcine ERM were stretched for 24 hr in cycles of 18% elongation for 1 sec followed by 1 sec relaxation. The numbers of cells and TUNEL-positive cells were then counted. The expression of mRNAs encoding gap junction protein ␣1 (Gja1), ameloblastin, bone morphogenetic protein 2 (BMP2 ), bone morphogenetic protein 4 (BMP4 ) and noggin were evaluated using quantitative real-time PCR. The number of cells in the stretching group was approximately 1.3-fold higher than that in the non-stretching controls at 24 hr (pϽ0.01). Apoptotic cells ranged from 1.9-2.5% in the stretching group at 24 hr, but were only 0.6% in the control group (pϽ0.01). The expression of Gja1, ameloblastin and noggin mRNAs in the stretching group was decreased at 24 hr compared with in the non-stretching group (pϽ0.01), whereas the expression of BMP2 and BMP4 mRNAs in the stretching group was significantly higher than that in the control group (pϽ0.01). Incorporation of 18 ␣-glycyrrhetinic acid (18GA, a gap junction inhibitor) promoted proliferation and apoptosis and confirmed both the increase of BMP2 and BMP4 and the decline of Gja1, ameloblastin and noggin in ERM. Thus, the ERM modulate cell proliferation and apoptosis, and inhibit differentiation by reducing expression of Gja1 under mechanical stretching.

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“…Cx43, a ubiquitously expressed connexin, is identified in virtually all types of bone cells, including cultured osteoblasts from newborn rat calvaria (13), human bone marrow stromal cells, trabecular bone osteoblasts (14), murine osteoblasts (15), primary osteocytes in vivo (16), mandibular bone and periodontal ligament cells of rat teeth (17), osteoblast-like MC3T3-E1 cells (18,19), osteocyte-like MLO-Y4 cells (20,21) and chondrocytes from articular and growth plate cartilage (22)(23)(24). Cx45 and Cx46 are expressed in several established osteoblast cell lines.…”

Section: Gap Junctions In Bone Cellsmentioning

confidence: 99%

Roles of gap junctions and hemichannels in bone cell functions and in signal transmission of mechanical stress

Jiang¹,

2007

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Gap junctions formed by connexins (Cx) play an important role in transmitting signals between bone cells such as osteoblasts and osteoclasts, cells responsible for bone formation and bone remodeling, respectively. Gap junction intercellular communication (GJIC) has been demonstrated to mediate the process of osteoblast differentiation and bone formation. Furthermore, GJIC propagates Ca 2+ signaling, conveys anabolic effects of hormones and growth factors, and regulates gene transcription of osteoblast differentiation markers. GJIC is also implicated to regulate osteoclast formation, survival and apoptosis. Compared with other bone cells, the most abundant type are osteocytes, which express large amounts of connexins. Mechanosensing osteocytes connect and form gap junctions with themselves and other cells only through the tips of their dendritic processes, a relatively small percent of the total cell surface area compared to other cells. Recent studies show that in addition to gap junctions, osteoblasts and osteocytes express functional hemichannels, the un-opposed halves of gap junction channels. Hemichannels are localized at the cell surface and function independently of gap junctions. Hemichannels in osteocytes mediate the immediate release of prostaglandins in response to mechanical stress. The major challenges remaining in the field are how the functions of these two types of channels are coordinated in bone cells and what the asserted, distinct effects of these channels are on bone formation and remodeling processes, and on conveying signals elicited by mechanical loading. KeywordsBone; Gap Junctions; Hemichannels; Cx43; Connexin; Osteoblast; Osteocyte; Mechanical Stress; Review INTRODUCTION Gap Junctions in Bone CellsGap junctions are transmembrane channels, which connect the cytoplasm of adjacent cells. These channels permit molecules with molecular weights approximately less than 1 kD a such as small metabolites, ions, and intracellular signaling molecules (i.e. calcium, cAMP, inositol triphosphate) to pass through. Gap junction channels have been demonstrated to be important in modulating cell signaling and tissue function in many organs, such as heart, liver, peripheral nerve, ovary, ear and lens of the eye (1-8). Gap junctions are formed by members of a family of sequentially and structurally related proteins known as connexins. Approximately twenty connexins have been identified and cloned from various tissues and cells (9-11). Six monomers of connexins are joined head-to-head across the extracellular "gap" between two adjacent cells (21,26,27). However, we found that Cx45 protein is expressed in bone marrow, but not in osteoblasts, osteocytes and osteoclasts in the alveolar bone tissues of the tooth (28).Functional gap junctions in osteoblasts were first demonstrated with electrical conductance and dye injection (29). Voltage-sensitive gap junction currents were detected in osteoblastic cells derived from calvarias of new-born rats with a single gap junction channel conductance of approxim...

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Expression of Connexin 43 in Rat Mandibular Bone and Periodontal Ligament (PDL) Cells during Experimental Tooth Movement

Cited by 75 publications

References 22 publications

A paradigm shift for bone quality in dentistry: A literature review

A paradigm shift for bone quality in dentistry: A literature review

Epithelial Cell Rests of Malassez Modulate Cell Proliferation, Differentiation and Apoptosis via Gap Junctional Communication under Mechanical Stretching in vitro

Roles of gap junctions and hemichannels in bone cell functions and in signal transmission of mechanical stress

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