Effect of Epidermal Growth Factor on Collagen Synthesis in Osteoblastic Cells Derived from Newborn Mouse Calvaria

Hiramatsu, Masahiko; Kumegawa, Masayoshi; Hatakeyama, Keiko; Yajima, Toshihiko; Minami, Naomi; Kodama, Hiroaki

doi:10.1210/endo-111-6-1810

Cited by 41 publications

(14 citation statements)

References 32 publications

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“…Therefore, it is tempting to suggest that EGF shifts osteoblasts to cells with a less differentiated phenotype. EGF has a proliferative effect on osteoblasts, as judged by an increase of DNA synthesis, [3H]-thymidine incorporation, and cell number [16,17,19]. In the present study, no effect on DNA synthesis and protein content was observed after incubation with EGF.…”

Section: Discussioncontrasting

confidence: 52%

“…In other studies with various osteoblast-like ceils, EGF has been shown to decrease alkaline phosphatase activity, hydroxyproline content, and collagen synthesis [16,19]. Among the osteosarcoma cell lines, there is a close relation between, on the one hand, the presence of receptors for and biological responses to 1,25(OH)2D3 and on the other hand, osteoblastic properties such as elevated alkaline phosphatase activity and bone formation in subcutaneous tumors [32].…”

Section: Discussionmentioning

confidence: 91%

“…As for 1,25(OH)2D 3 and PTH, the receptor for EGF in bone is located on the osteoblast [14,15]. EGF stimulates DNA and protein synthesis and prostaglandin production in osteoblasts of various origin [16][17][18] whereas collagen synthesis, hydroxyproline content, and alkaline phosphatase activity are reduced by EGF [16,19]. Furthermore, EGF may modulate osteoblast responses to calciotrophic hormones.…”

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confidence: 99%

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Modulation by epidermal growth factor of the basal 1,25(OH)2D3 receptor level and the heterologous up-regulation of the 1,25(OH)2D3 receptor in clonal osteoblast-like cells

et al. 1991

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Summary. The effects of epidermal growth factor (EGF) on basal 1,25-dihydroxyvitamin D 3 (1,25-(OH)2D3) receptor level and on parathyroid hormone (PTH)-induced 1,25-(OH)2D3 receptor up-regulation were studied in the phenotypically osteoblastic cell line UMR 106. EGF in concentrations exceeding 0.1 ng/ml reduced the number of 1,25(OH)2D 3 binding sites without changing the binding affinity. Maximal reduction was 30% at about 1 ng/ml. This reduction was independent of a change in cAMP content. EGF dose-dependently attenuated both PTH-induced 1,25(OH)2D 3 receptor up-regulation and PTH-stimulated cAMP production, without an effect on the EDso of the PTH effects. For both PTH responses the IC5o and the maximal effective dose were similar, 0.1 ng/ml and 1 ng/ml EGF, respectively. Reduction was first seen at 0.01 ng/ml EGF. At this concentration, EGF reduced PTH-stimulated 1,25-(OH)2D 3 receptor binding without an inhibition of the cAMP response. Time-course studies with 1 ng/ml EGF revealed that at 2 h preincubation EGF reduced the heterologous upregulation by PTH, and maximal inhibition was seen after 4 h. In contrast, PTH-stimulated cAMP production was just significantly inhibited only after 6 h, with 60% inhibition after 24 h preincubation. The effects of prostaglandin E 2 and forskolin on both 1,25(OH)eD3 binding and cAMP production were inhibited in a similar fashion. On the other hand, dibutyryl cAMP-and 3-isobutyl-l-methylxanthinestimulated 1,25(OH)2D3 binding were not affected by EGF. Taken together, our results demonstrate that EGF reduces both the basal number of 1,25(OH)2D3 binding sites and the heterologous up-regulation of the 1,25(OH)2D 3 receptor. The current data suggest that EGF reduces heterologous upregulation of the 1,25(OH)2D3 receptor independent of as well as dependent on the cAMP messenger system. The EGF effect is not primarily located at the PTH receptor, at cAMP phosphodiesterase, or at protein kinase A level.Key words: EGF-1,25(OH)zD 3 binding -PTH -Osteoblast cell line.1,25-Dihydroxyvitamin D 3 (1,25(OH)2D3) and parathyroid hormone (PTH) play an important role in calcium homeostasis. One of the target tissues for 1,25(OH)2D3 and PTH is bone. For both hormones the receptors in bone are located on the osteoblast [1][2][3][4]. From in vitro as well as in vivo studies, evidence has been obtained indicating that 1,25 (OH)2D 3 and PTH act in an interrelated fashion [5,6]. Also at the level of the osteoblast, interactions between 1,25(OH)2D 3 and PTH have been reported. For instance, preincubation of osteoblast-like cells with 1,25(OH)2D 3 attenuates the stimulation of cAMP production by PTH [7][8][9][10]. Furthermore, we have recently reported that PTH and PTHrelated protein cause heterologous up-regulation of the 1,25(OH)2D3 receptor [11].It has been shown that besides these two well-known calciotrophic hormones, growth factors and cytokines also affect bone cell metabolism. One of these polypeptide growth factors is epidermal growth factor (EGF) which has been shown to stimulate bone resorpti...

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Section: Discussioncontrasting

confidence: 52%

Section: Discussionmentioning

confidence: 91%

mentioning

confidence: 99%

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Modulation by epidermal growth factor of the basal 1,25(OH)2D3 receptor level and the heterologous up-regulation of the 1,25(OH)2D3 receptor in clonal osteoblast-like cells

et al. 1991

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“…Collagen prolyl hydroxylase activity was stimulated by EGF in the cotton-pellet granuloma system of Hiramatsu et al (7); however, the significance of this is uncertain since collagen synthesis was not directly determined in that study, and this enzyme activity is usually not rate-limiting for collagen synthesis (25). These authors also reported an EGF-mediated increase in this enzyme in cloned osteoblastic cells, yet a decrease in collagen synthesis was noted (26). In addition, EGF reduced collagen fiber formation and stimulated the production of type III collagen by osteoblastic cells (9).…”

Section: Resultsmentioning

confidence: 93%

Sustained release of epidermal growth factor accelerates wound repair.

Buckley¹,

Davidson²,

Kamerath³

et al. 1985

Proc. Natl. Acad. Sci. U.S.A.

265

124

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Epidermal growth factor (EGF) is a potent mitogen in vitro, but its biological role is less clear. The vulnerary effects of EGF were evaluated in a model of wound repair, the polyvinyl alcohol sponge implanted subcutaneously in rats. EGF was purified to homogeneity by reverse-phase HPLC and quantified by receptor binding assay and amino acid analysis. Preliminary data showed moderate promotion of granulation tissue formation by daily injections of 10 /Ag of EGF. To test the hypothesis that long-term exposure to EGF is required for complete cellular response, the factor was incorporated into pellets releasing 10 or 20 jig of biologically active EGF per day, and the pellets were embedded within the sponges. Slow release of EGF caused a dramatic increase in the extent and organization of the granulation tissue at day 7, a doubling in the DNA content, and 33% increases in protein content and wet weight, as compared with placebo controls. Although collagen content was also increased by almost 50%, the relative rate of collagen synthesis remained the same, suggesting that the morphological and biochemical increase in coflagen resulted from increased numbers of fibroblasts rather than a specific stimulation of collagen synthesis. These results indicate that the local sustained presence ofEGIF accelerates the process of wound repair, specifically neovascularization, organization by fibroblasts, and accumulation of collagen.Epidermal growth factor (EGF) stimulates a variety of biological phenomena, including proliferation of skin and corneal epithelia in organ culture, proliferation and differentiation of epidermis and corneal epithelial cells in vivo (1), neoangiogenesis in the rabbit cornea (2), and the synthesis of DNA, RNA, protein, and hyaluronic acid in various cell lines in culture (1). Many cell types, including dermal fibroblasts, possess EGF surface receptors and will proliferate in response to EGF in cell culture (3). By contrast to the many observations in vitro, the function of growth factors during wound repair is not clear. This is in part the result of the difficulty of delivering growth factors and quantifying the responses to them in vivo.The process of healing surface wounds includes reepithelization, neovascularization, granulation tissue development, collagen elaboration, maturation and remodeling of the scar, and contraction (4). During the early phases of repair, the local accumulation of collagen strongly correlates with the accretion of tensile strength (5); hence, measuring the content and concentration of collagen at a repair site permits an estimate of the rate of healing.

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“…P4H isoenzymes are expressed in most tissues, although there may be tissue specificity with regard to type I or II isoforms for the ␣ subunit (12)(13)(14). Although relatively little data is available for factors affecting P4H expression and activity, P4H may be regulated by nitric oxide, tumor necrosis factor ␣, transforming growth factor ␤ (TGF␤), insulin-like growth factor 1, ␤ fibroblast growth factor, certain cytokines, and cigarette smoking (15)(16)(17)(18)(19)(20)(21)(22). Environmental stimuli, such as hypoxia, can induce P4H␣(I) expression at both transcriptional and post-transcriptional levels, which results in excess accumulation of collagen, a process relevant to fibrosis (23,24).…”

mentioning

confidence: 99%

Human Prolyl-4-hydroxylase α(I) Transcription Is Mediated by Upstream Stimulatory Factors

Chen

Shen

Wang

et al. 2006

Journal of Biological Chemistry

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Prolyl-4-hydroxylase ␣(I) (P4H␣(I)) is the rate-limiting subunit for P4H enzyme activity, which is essential for procollagen hydroxylation and secretion. In the current study, we have characterized the human P4H␣(I) promoter for transcription factors and DNA elements regulating P4H␣(I) expression. Using a progressive deletion cloning approach, we have constructed pGL3-P4H␣(I) recombinant plasmids. We have identified a positive regulatory region at the positions of bp ؊184 to ؊97 responsible for ϳ80% of the P4H␣(I) promoter efficiency. Three E-boxes were located within this region, and the E-box at position bp ؊135 explains most of the regulatory capacity. Upstream stimulatory factors (USF1/USF2) were shown to bind on the E-box using chromatin immunoprecipitation assay. Suppression of USF1 and/or USF2 using specific short interference RNA resulted in a significant reduction in P4H␣(I) promoter activity, and overexpressed USF1 or USF2 increased P4H␣(I) promoter activity significantly. Although transforming growth factor ␤1 increased the USF1/USF2-E-box binding and P4H␣(I) promoter activity, this up-regulatory effect can be largely prevented by USF1/ USF2-specific short interference RNA. On the other hand, cigarette smoking extracts, which have been shown to suppress P4H␣(I) expression, inhibited the binding between the USF1/USF2 and E-box, resulting in a reduced P4H␣(I) promoter activity. Furthermore, the E-box on the P4H␣(I) promoter appeared to indiscriminately bind with either USF1 or USF2, with a similar outcome on the promoter efficiency. In conclusion, our study shows that USF1/ USF2 plays a critical role in basal P4H␣(I) expression, and both positive (transforming growth factor ␤1) and negative (cigarette smoking extract) regulators appear to influence the USF-E-box interaction and affect P4H␣(I) expression.

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Effect of Epidermal Growth Factor on Collagen Synthesis in Osteoblastic Cells Derived from Newborn Mouse Calvaria

Cited by 41 publications

References 32 publications

Modulation by epidermal growth factor of the basal 1,25(OH)2D3 receptor level and the heterologous up-regulation of the 1,25(OH)2D3 receptor in clonal osteoblast-like cells

Modulation by epidermal growth factor of the basal 1,25(OH)2D3 receptor level and the heterologous up-regulation of the 1,25(OH)2D3 receptor in clonal osteoblast-like cells

Sustained release of epidermal growth factor accelerates wound repair.

Human Prolyl-4-hydroxylase α(I) Transcription Is Mediated by Upstream Stimulatory Factors

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