Characterization of gap junctions between osteoblast-like cells in culture

Schirrmacher, K.; Schmitz, Inge; Winterhager, Elke; Traub, Otto; Brümmer, Franz; Jones, David B.; Bingmann, D.

doi:10.1007/bf00334489

Cited by 106 publications

(56 citation statements)

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“…Gap junctions are implicated in metabolic cooperation, differentiation and growth of cells (13). It has been shown that Cx43is a major gap junction protein in osteoblasts, and that the Cx43expression is correlated with the extent of intercellular communication (6,25,26,27). Wehave recently found that the Cx43 expression in osteoblasts is associated with an increase in cell density (3).…”

Section: Resultsmentioning

confidence: 99%

“…Osteoblasts and osteocytes in bone matrix in vivo are connected with each other, forming a cell-cell network via gap junctions (8,15,18,21). It has become clear that connexin 43 (Cx43) is a major gap junction protein expressed in osteoblastic cells (6,25,26,27). Wehave recently observed that the expression of Cx43 in osteoblastic cells was induced with an increase in cell density (3 Nissui Pharmaceutical, Tokyo, Japan) supplemented with 0.5% bovine serum albumin (Albumax; Gibco Laboratories, Grant Island, NY), ITS (containing 5^g/ml insulin, 5^g/ml transferrin and 5 ng/ml selenious acid; Collaborative Research, Inc., Bed ford, MA), lOO U/ml penicillin and 100^g /ml streptomycin (Gibco Laboratories).…”

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confidence: 99%

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Hormonal Regulation of Connexin 43 Expression and Gap Junctional Communication in Human Osteoblastic Cells.

Chiba

Sawada

Oyamada

et al. 1994

Cell Struct. Funct.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Hormonal Regulation of Connexin 43 Expression and Gap Junctional Communication in Human Osteoblastic Cells.

Chiba

Sawada

Oyamada

et al. 1994

Cell Struct. Funct.

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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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“…Connexins have been identified in bone tissues by morphological, structural, and functional analyses [4][5][6][7]. Among the members of the connexin family, Connexin43 (Cx43) is the most ubiquitously expressed in virtually all types of bone cells [8][9][10][11]. Genetic studies have demonstrated that both gap junction and Cx43 play essential roles in the bone development and turnover of human and animal models in vivo.…”

Section: Introductionmentioning

confidence: 99%

Role of Cx43-Based Gap Junction in Murine Osteoblast-Like Mc3t3-E1Cells Exposed to 17-Βestradiol

Shang¹,

Wei²,

Liang³

2017

Mol Biol

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Estrogen has garnered considerable attention because of its importance in bone mass maintenance and the efficacy of hormone therapy in combating postmenopausal osteoporosis. Gap junctions are membrane spanning protein channels present on the surfaces of adjacent cells. They enable neighboring cells to physically link, which facilitate intercellular communication by allowing passage of small molecules from cell to cell in a process known as Gap Junctional Intercellular Communication (GJIC), can make the relevant cells function as a whole. An in vitro experiment combined with microarray analyses has identified novel genes in the response of MC3T3-E1 cells to an appropriate concentration of 17-β estradiol and the results of microarray showed that gap junction alpha-1 (Gja1) in the gap junction pathway was significantly elevated. We studied the effect of 17-β estradiol on the proliferation and differentiation of MC3T3-E1 cells disrupting of GJIC among osteoblasts with the chemical inhibitor, 18α-Glycyrrhetinic Acid (AGA). And we found that an appropriate concentration and duration of 17-β estradiol increased Methyl Thiazol Tetrazolium (MTT) values, Alkaline Phosphatase (ALP) activity and Runt-related transcription factor 2 (Runx2) proteins and gene expression and facilitated the mineralization of extracellular matrix. However, the promoting effect of 17-β estradiol on the proliferation and differentiation of MC3T3-E1 cells was weakened under the action of AGA. Therefore, we suggest that 17-β estradiol promotes MC3T3-E1's proliferation, differentiation and functions associated with Cx43-based GJIC, but gap junction is not the only signaling pathway that mediates the influence of 17-β estradiol on osteoblasts. The specific regulatory mechanism has yet to be researched.

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Characterization of gap junctions between osteoblast-like cells in culture

Cited by 106 publications

References 37 publications

Hormonal Regulation of Connexin 43 Expression and Gap Junctional Communication in Human Osteoblastic Cells.

Hormonal Regulation of Connexin 43 Expression and Gap Junctional Communication in Human Osteoblastic Cells.

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

Role of Cx43-Based Gap Junction in Murine Osteoblast-Like Mc3t3-E1Cells Exposed to 17-Βestradiol

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