Endocrinology, Vol 135, 2358-2363, Copyright © 1994 by Endocrine Society

ARTICLES

Glycosaminoglycans inhibit degradation of insulin-like growth factor- binding protein-5

T Arai, A Arai, WH Busby Jr and DR Clemmons
Department of Medicine, University of North Carolina, Chapel Hill 27599.

Human dermal fibroblasts secrete insulin-like growth factor-binding protein-3 (IGFBP-3), -4, and -5. Fibroblast-conditioned medium contains minimal intact IGFBP-5, and this form of IGFBP is predominantely a 23- kilodalton fragment, suggesting that the IGFBP-5 fragment is derived from intact IGFBP-5 by proteolysis. In this study we investigated the effects of glycosaminoglycans on IGFBP-5 degradation in fibroblast- conditioned medium. The addition of heparin, heparan sulfate, and dermatan sulfate (100 micrograms/ml) to the medium of fibroblast monolayer cultures inhibited IGFBP-5 degradation, as determined by the conversion of intact IGFBP-5 to a 23-kilodalton fragment. In contrast, hyaluronic acid, keratan sulfate, and chondroitin sulfate-A and -C had no effect. Heparin and heparan sulfate inhibited IGFBP-5 degradation at concentrations of 1 or 2.5 micrograms/ml, but 100 micrograms/ml dermatan sulfate were required. Heparin was also inhibitory in vitro, that is when conditioned medium and heparin were incubated without cells. Experiments with modified forms of heparin showed that O-sulfate groups in the 2 or 3 carbon position were required for heparin to be inhibitory. Completely desulfated heparin had no activity, and N- resulfation of desulfated heparin had only a minimal effect. Dextran sulfate, pentosan polysulfate, and fucoidan, which are composed of different saccharide units but contain O-sulfate groups in the 2 or 3 carbon positions, also inhibited IGFBP-5 degradation. These results demonstrate that heparin-like molecules are important regulators of IGFBP-5 degradation. O-Sulfation of the 2 or 3 position of the saccharide ring is required for inhibitory activity. As glycosaminoglycan side-chains are present in proteoglycans that are present in extracellular matrix and on cell surfaces, these side-chains represent a potential mechanism for regulating IGFBP-5 proteolysis in vivo.

This article has been cited by other articles:

				K. S. Kim, Y. B. Seu, S.-H. Baek, M. J. Kim, K. J. Kim, J. H. Kim, and J.-R. Kim Induction of Cellular Senescence by Insulin-like Growth Factor Binding Protein-5 through a p53-dependent Mechanism Mol. Biol. Cell, November 1, 2007; 18(11): 4543 - 4552. [Abstract] [Full Text] [PDF]

				M. Oufattole, S. W.-J. Lin, B. Liu, D. Mascarenhas, P. Cohen, and B. D. Rodgers Ribonucleic Acid Polymerase II Binding Subunit 3 (Rpb3), a Potential Nuclear Target of Insulin-Like Growth Factor Binding Protein-3 Endocrinology, May 1, 2006; 147(5): 2138 - 2146. [Abstract] [Full Text] [PDF]

				J. Beattie, K. Phillips, J. H Shand, M. Szymanowska, D. J Flint, and G. J Allan Molecular recognition characteristics in the insulin-like growth factor (IGF)-insulin-like growth factor binding protein -3/5 (IGFBP-3/5) heparin axis J. Mol. Endocrinol., February 1, 2005; 34(1): 163 - 175. [Abstract] [Full Text] [PDF]

				S. R. Edmondson, S. P. Thumiger, G. A. Werther, and C. J. Wraight Epidermal Homeostasis: The Role of the Growth Hormone and Insulin-Like Growth Factor Systems Endocr. Rev., December 1, 2003; 24(6): 737 - 764. [Abstract] [Full Text] [PDF]

				J.M. Gibson, J.D. Aplin, A. White, and M. Westwood Regulation of IGF bioavailability in pregnancy Mol. Hum. Reprod., January 1, 2001; 7(1): 79 - 87. [Abstract] [Full Text] [PDF]

				H. Miyake, C. Nelson, P. S. Rennie, and M. E. Gleave Overexpression of Insulin-Like Growth Factor Binding Protein-5 Helps Accelerate Progression to Androgen-Independence in the Human Prostate LNCaP Tumor Model through Activation of Phosphatidylinositol 3'-Kinase Pathway Endocrinology, June 1, 2000; 141(6): 2257 - 2265. [Abstract] [Full Text] [PDF]

				H. Miyake, M. Pollak, and M. E. Gleave Castration-induced Up-Regulation of Insulin-like Growth Factor Binding Protein-5 Potentiates Insulin-like Growth Factor-I Activity and Accelerates Progression to Androgen Independence in Prostate Cancer Models Cancer Res., June 1, 2000; 60(11): 3058 - 3064. [Abstract] [Full Text] [PDF]

				E. Tonner, M. C. Barber, M. T. Travers, A. Logan, and D. J. Flint Hormonal Control of Insulin-Like Growth Factor-Binding Protein-5 Production in the Involuting Mammary Gland of the Rat Endocrinology, December 1, 1997; 138(12): 5101 - 5107. [Abstract] [Full Text] [PDF]

				C. K. Abrass, A. K. Berfield, and D. L. Andress Heparin binding domain of insulin-like growth factor binding protein-5 stimulates mesangial cell migration Am J Physiol Renal Physiol, December 1, 1997; 273(6): F899 - F906. [Abstract] [Full Text] [PDF]

				P. G. Campbell and D. L. Andress Plasmin degradation of insulin-like growth factor-binding protein-5 (IGFBP-5): regulation by IGFBP-5-(201---218) Am J Physiol Endocrinol Metab, November 1, 1997; 273(5): E996 - E1004. [Abstract] [Full Text] [PDF]

				P. G. Campbell and D. L. Andress Insulin-like growth factor (IGF)-binding protein-5-(201---218) region regulates hydroxyapatite and IGF-I binding Am J Physiol Endocrinol Metab, November 1, 1997; 273(5): E1005 - E1013. [Abstract] [Full Text] [PDF]

				T. J. Nam, W. Busby Jr., D. R. Clemmons, T. J. Nam, W. Busby Jr., and D. R. Clemmons Insulin-Like Growth Factor Binding Protein-5 Binds to Plasminogen Activator Inhibitor-I Endocrinology, July 1, 1997; 138(7): 2972 - 2983. [Abstract] [Full Text] [PDF]

				A. Parker, J. B. Clarke, W. H. Busby Jr., and D. R. Clemmons Identification of the Extracellular Matrix Binding Sites for Insulin-like Growth Factor-binding Protein 5 J. Biol. Chem., June 7, 1996; 271(23): 13523 - 13529. [Abstract] [Full Text] [PDF]

				T. Arai, J. Clarke, A. Parker, W. Busby Jr., T. Nam, and D. R. Clemmons Substitution of Specific Amino Acids in Insulin-like Growth Factor (IGF) Binding Protein 5 Alters Heparin Binding and Its Change in Affinity for IGF-I in Response to Heparin J. Biol. Chem., March 15, 1996; 271(11): 6099 - 6106. [Abstract] [Full Text] [PDF]

				C. Duan, S. B. Hawes, T. Prevette, and D. R. Clemmons Insulin-like Growth Factor-I (IGF-I) Regulates IGF-binding Protein-5 Synthesis through Transcriptional Activation of the Gene in Aortic Smooth Muscle Cells J. Biol. Chem., February 23, 1996; 271(8): 4280 - 4288. [Abstract] [Full Text] [PDF]

				D. L. Andress and D. L. Andress Heparin Modulates the Binding of Insulin-like Growth Factor (IGF) Binding Protein-5 to a Membrane Protein in Osteoblastic Cells J. Biol. Chem., November 24, 1995; 270(47): 28289 - 28296. [Abstract] [Full Text] [PDF]

				J. L. Fowlkes, D. M. Serra, C. K. Rosenberg, and K. M. Thrailkill Insulin-like Growth Factor (IGF)-binding Protein-3 (IGFBP-3) Functions as an IGF-reversible Inhibitor of IGFBP-4 Proteolysis J. Biol. Chem., November 17, 1995; 270(46): 27481 - 27488. [Abstract] [Full Text] [PDF]