Intact insulin-like growth factor binding protein-5 (IGFBP-5) associates with bone matrix and the soluble fragments of IGFBP-5 accumulated in culture medium of neonatal mouse calvariae by parathyroid hormone and prostaglandin E2-treatment

Hakeda, Yoshiyuki; Kawaguchi, Hiroshi; Hurley, Marja M.; Pilbeam, Carol C.; Abreu, Christine; Linkhart, Thomas A.; Mohan, Subburaman; Kumegawa, Masayoshi; Raisz, Lawrence G.

doi:10.1002/(sici)1097-4652(199602)166:2<370::aid-jcp15>3.0.co;2-f

Cited by 35 publications

References 58 publications

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Insulin-like growth factor binding proteins localize to discrete cell culture compartments in periosteal and osteoblast cultures from fetal rat bone

Chen

Shu

et al. 1998

J. Cell. Biochem.

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Insulin-like growth factor (IGF)-I and IGF-II are expressed at biologically effective levels by bone cells. Their stability and activity are modulated by coexpression of IGF binding proteins (IGFBPs). Secreted IGFBPs may partition to soluble, cell-associated, and matrix-bound compartments. Extracellular localization may sequester, store, or present IGFs to appropriate receptors. Of the six IGFBPs known, rat osteoblasts synthesize all but IGFBP-1. Of these, IGFBP-3, -4, and -5 mRNAs are induced by an increase in cAMP. Little is known about extracellular IGFBP localization in bone and nothing about IGFBP expression by nonosteoblastic periosteal bone cells. We compared basal IGFBP expression in periosteal and osteoblast bone cell cultures and assessed the effects of changes in cAMP-dependent protein kinase A or protein kinase C. Basal IGFBP gene expression differed principally in that more IGFBP-2 and -5 occurred in osteoblast cultures, and more IGFBP-3 and -6 occurred in periosteal cultures. An increase in cAMP enhanced IGFBP-3, -4, and -5 mRNAand accordingly increased soluble IGFBP-3, -4, and -5 and matrix-bound IGFBP-3 and -5 in both bone cell populations. In contrast, protein kinase C activators suppressed IGFBP-5 mRNA, and its basal protein levels remained very low. We also detected low Mr bands reactive with antisera to IGFBP-2, -3, and -5, suggesting proteolytic processing or degradation. Our studies reveal that various bone cell populations secrete and bind IGFBPs in selective ways. Importantly, inhibitory IGFBP-4 does not significantly accumulate in cell-associated compartments, even though its secretion is enhanced by cAMP. Because IGFBPs bind IGFs less tightly in cell-bound compartments, they may prolong anabolic effects by agents that increase bone cell cAMP.

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Insulin-like growth factor binding proteins localize to discrete cell culture compartments in periosteal and osteoblast cultures from fetal rat bone

Chen

Shu

et al. 1998

J. Cell. Biochem.

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Insulin‐Like Growth Factor Binding Proteins

Clemmons

1999

Comprehensive Physiology

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The sections in this article are: Gene Structures Insulin‐Like Growth Factor Binding Protein 1 Insulin‐Like Growth Factor Binding Protein 2 Insulin‐Like Growth Factor Binding Protein 3 Insulin‐Like Growth Factor Binding Protein 4 Insulin‐Like Growth Factor Binding Protein 5 Insulin‐Like Growth Factor Binding Protein 6 Acid Labile Subunit Protein Structures Insulin‐Like Growth Factor Binding Protein 1 Insulin‐Like Growth Factor Binding Protein 2 Insulin‐Like Growth Factor Binding Protein 3 Insulin‐Like Growth Factor Binding Protein 4 Insulin‐Like Growth Factor Binding Protein 5 Insulin‐Like Growth Factor Binding Protein 6 Insulin‐Like Growth Factor Binding Protein‐Related Proteins Control of Gene Expression, Synthesis, and Secretion of Insulin‐Like Growth Factor Binding Proteins by Cells and Tissues Tissue Expression Secretion by Cells In Vitro Variables that Regulate Pericellular Abundanbce of Insulin‐Like Growth Factor Binding Proteins Proteolysis Phosphorylation of Insulin‐Like Growth Factor Binding Proteins Binding to Cell Surfaces and to Extracellular Matrix Regulation of Insulin‐Like Growth Factor Actions in vitro and in vivo Regulation of Half‐Life Modulation of Insulin‐Like Growth Factor Actions Specific Functions of Each Form of Binding Protein A Unified Theory of the Mechanism of Action of Insulin‐Like Growth Factor Binding Proteins in Connective Tissue Cells Use of Insulin‐Like Growth Factor Analogs Related Proteins Control of Insulin‐Like Growth Factor Binding Protein Concentrations in Physiologic Fluids Methodologic Considerations Detection of Insulin‐Like Growth Factor Binding Proteins in Physiologic Fluids Other than Blood Regulation of Insulin‐Like Growth Factor Binding Proteins in Serum Regulation of Insulin‐Like Growth Factor Binding Proteins by Hormones Summary

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Anabolic effects of prostaglandins in cultured fetal rat calvariae: Structure-activity relations and signal transduction pathway

Woodiel

Fall

Raisz

1996

Journal of Bone and Mineral Research

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The structure-activity relations and signal transduction pathways for the anabolic effects of prostaglandins were examined in cultured fetal rat calvariae. In the presence of cortisol prostaglandins of the E and F series (10(-9) to 10(-5) M) produced a dose-related increase in [3H]thymidine incorporation up to 4-fold at 24 h. Prostaglandin E2 (PGE2) was also effective in the absence of cortisol. Butaprost (10(-6) M), a selective EP-2 receptor agonist, produced partial stimulation. Prostaglandin D2, prostacyclin, sulprostone, an EP-1 and EP-3 receptor agonist, and fluprostenol, an FP receptor agonist, were ineffective. Forskolin (10(-4) M) increased [3H]thymidine incorporation 3-fold, while phorbol myristate acetate (PMA) (10(-6) M) produced a 1.8-fold increase. Isobutylmethylxanthine (IBMX) increased [3H]thymidine incorporation in control cultures, in the absence of cortisol, and increased the response to PGE2 in control and cortisol-treated cultures. [3H]proline incorporation into collagen and noncollagen protein was measured in the continuous presence of prostaglandins and cortisol for 72-96 h (continuous model) or when prostaglandins and cortisol were applied for 24 h, followed by culture for 48 h in control medium (on/off model). The effects on collagen were greater than on noncollagen proteins, so that the percent of collagen synthesis increased. The effects of prostaglandins and forskolin paralleled their mitogenic effects. PMA increased only noncollagen protein. Indomethacin did not diminish the anabolic response, while aphidicolin produced only partial inhibition. We conclude that the anabolic effects of prostaglandins on replication and differentiation of osteoblasts are likely to be mediated by an EP-2 receptor that stimulates adenylate cyclase.

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Intact insulin-like growth factor binding protein-5 (IGFBP-5) associates with bone matrix and the soluble fragments of IGFBP-5 accumulated in culture medium of neonatal mouse calvariae by parathyroid hormone and prostaglandin E2-treatment

Cited by 35 publications

References 58 publications

Insulin-like growth factor binding proteins localize to discrete cell culture compartments in periosteal and osteoblast cultures from fetal rat bone

Insulin-like growth factor binding proteins localize to discrete cell culture compartments in periosteal and osteoblast cultures from fetal rat bone

Insulin‐Like Growth Factor Binding Proteins

Anabolic effects of prostaglandins in cultured fetal rat calvariae: Structure-activity relations and signal transduction pathway

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