A Comparison of Type I Collagen, Fibronectin, and Vitronectin in Supporting Adhesion of Mechanically Strained Osteoblasts

Lacouture, Mario E.; Schaffer, Jonathan; Klickstein, Lloyd B.

doi:10.1359/jbmr.2002.17.3.481

Cited by 50 publications

(29 citation statements)

References 55 publications

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“…The influence of mechanical force on collagen expression has been extensively investigated, as tissues in the musculoskeletal system are under constant mechanical loading. Within a variety of cell types, including the SaOs-2 cell line, mechanical loading has been demonstrated to have an influence on the gene expression of collagen types I and III (Kim et al 2002;Lacouture et al 2002;Jones et al 1991). Our group has also demonstrated that a 24-h cyclic mechanical loading of 5% strain at 0.5 Hz can increase collagen I and III mRNA synthesis in porcine ACL fibroblasts (Lee et al 2004a,b).…”

Section: Discussionmentioning

confidence: 87%

Strain-related collagen gene expression in human osteoblast-like cells

2005

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The gene expression of cells in the musculoskeletal system, such as in bone, cartilage, ligament and tendon, is profoundly affected by mechanical loading. Previous studies have demonstrated that the expression of many genes, including collagen types I and III, are affected by mechanical strain in diverse cell types, such as human osteoblast-like SaOs-2 cells. However, whether the effect of mechanical loading on collagen gene expression is strain-related remains unclear. The goal of this study was to determine the relationship between mechanical strain and the gene expression of collagen types I and III in SaOs-2 cells. A Flexercell cellular mechanical loading system was used to subject SaOs-2 cells to equibiaxial cyclic tensile stress at a rate of 0.5 Hz with various strains of 5%, 7.5%, 10%, and 12.5% for 24 h. The relative amount of mRNA of both collagen I and collagen III increased at 5% strain compared with that of the control. As the strain increased, the relative amount of mRNA of collagen I remained stable at strain levels up to 12.5%. However, the mRNA for collagen III began to drop when the strain was greater than 5%, until a 10% strain was reached. From the application of a 10% strain through the maximum loading of a 12.5% strain, the relative amount of collagen III mRNA remained stable at amounts lower than that of the control. Thus, the gene expression of collagen types I and III responds differentially to mechanical strain at various magnitudes.

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Section: Discussionmentioning

confidence: 87%

Strain-related collagen gene expression in human osteoblast-like cells

2005

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“…ECM components, such as, type 1 collagen, fibronectin, vitronectin, are present during specific stages of bone development and have been shown to have different roles in supporting adhesion of mechanically strained osteoblasts (88). Modified extracellular matrix molecule, sulfated hyaluronan, enhances the expression of Cx43 and N-cadherin, further resulting in remarkable induction of the alkaline phosphatase activity in rat osteoblast cells (89).…”

Section: Gap Junction Regulation By Hormones Growth Factors and Othementioning

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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“…The biological significance of the proliferation/ differentiation relationship is also necessary for an understanding of the manner in which perturbations in specific genes may be related to a broad spectrum of skeletal disorders (15)(16)(17)(18). Gene expression inducement is associated with ECM maturation and mineralization.…”

Section: Introductionmentioning

confidence: 99%

A comparison of osteogenesis-related gene expression of mesenchymal stem cells during the osteoblastic differentiation induced by Type-I collagen and/or fibronectin

Ozawa

Yamada

Nagasaka

2003

IJOMS

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Mesenchymal stem cells (MSCs) contain multipotent cells and differentiate into osteoblasts, chondrocytes, and adiphocytes. Recently, MSCs have been used clinically in a tissue-engineering concept, but cell activity varies. It was found that the characteristics of extracellular matrices, type Tcollagen and/or fibronectin matrices, induced the osteoblastic differentiation of MSCs. Six weeks after cells were cultured with type I collagen and fibronectin, they formed mineralized tissue six times higher than other matrices. In this study, using "real time RT-PCR," we assessed the expression of osteogenesis-related genes (alkaline phosphatase, BMP-2, osteocalcin, and cbfa-1) during osteoblastic differentiation by measuring their mRNA, quantitatively. The expression of the alkaline phosphatase gene increased time-dependently during osteoblastic differentiation until day 12, but expression induced by type I collagen and type I collagen and fibronectin decreased gradually. The expression of osteocalcin and the BMP-2 gene increased time-dependently; osteocalcin gene expression induced by type I collagen and fibronectin was about 6.2 times higher than noninduced cells. Expression of the cbfa-1 gene was different from that of type I collagen, fibronectin, and non-induced cells from day 12 and increased timedependently. These findings were supportedby alkaline phosphatasestaining and immunofluoresence with an osteopontin antibody.

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A Comparison of Type I Collagen, Fibronectin, and Vitronectin in Supporting Adhesion of Mechanically Strained Osteoblasts

Cited by 50 publications

References 55 publications

Strain-related collagen gene expression in human osteoblast-like cells

Strain-related collagen gene expression in human osteoblast-like cells

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

A comparison of osteogenesis-related gene expression of mesenchymal stem cells during the osteoblastic differentiation induced by Type-I collagen and/or fibronectin

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