Heparin inhibits the binding of basic fibroblast growth factor to cultured human aortic smooth-muscle cells

Abstract

Basic fibroblast growth factor (bFGF) and its specific receptors have diverse roles on a variety of cell types, such as the induction of vascular smooth-muscle cell proliferation which contributes to restenosis after coronary balloon angioplasty. bFGF is also known to interact with heparan sulphate proteoglycans present on the cell surface or in the extracellular matrix. In this study, the binding of 125I-bFGF to human aortic smooth-muscle cells was investigated. 125I-bFGF binding to these cells was reversible and saturable. Scatchard analysis revealed the presence of two distinct binding sites: a high-affinity receptor (Kd=38+/-7 pM; 1480+/-220 sites/cell) and a low-affinity non-saturable binding site (Kd=8. 0+/-2.0 nM). Pretreatment of the cells with heparinase resulted in a large reduction of 125I-bFGF binding to its low-affinity receptors, suggesting that they are heparin-like molecules. The specificity of the low- and high-affinity binding sites for bFGF was determined with acidic FGF, platelet-derived growth factor-BB and epidermal growth factor, which did not compete for 125I-bFGF binding. Expression of FGF receptor isoforms analysed by reverse transcriptase-PCR revealed the presence of only the type-1 receptor. Binding to low-affinity binding sites was antagonized by heparin, suramin, protamine sulphate and platelet factor 4. Unexpectedly, these molecules also reduced the binding of 125I-bFGF to its high-affinity sites. Consistent with these results, heparin, suramin, protamine sulphate and platelet factor 4 inhibited bFGF-induced proliferation of human aortic smooth-muscle cells. Heparin abrogated bFGF-induced release of tissue-type plasminogen activator by these cells. These observations suggest that the interaction of bFGF with human aortic smooth-muscle cells is different from that described for other cells such as endothelial cells, in which heparin acts as a potentiating factor of the mitogenic activity of bFGF.

Biodegradable elastomeric scaffolds with basic fibroblast growth factor release

“…[51,52] However, high concentrations of heparin inhibit the proliferation of smooth muscle cells. [53] The bFGF bioactivity from PEUU scaffolds without heparin indicated that commonly-used growth factor stabilizing protein BSA [20] alone could stabilize the bFGF and maintain smooth muscle cell mitogenicity. The incorporation of heparin may further stabilize the bFGF, but our data did not suggest such stabilization.…”

“…[24] Scaffolds loaded with 100 ng bFGF /mg PEUU (without I 125 -bFGF) were cut into 50 mg pieces. Samples were placed into a 15 mL conical tube and 10 mL release medium was added.…”

Effects of heparin on the production of homocysteine-induced extracellular matrix metalloproteinase-2 in cultured rat vascular smooth muscle cells

“…Heparin inhibits growth of baboon SMCs by preventing prolonged mitogen-activated protein kinase activation elicited by ligands of seven transmembrane domain receptors and heterotrimeric G-proteins (39). Bono et al (40) showed that heparin inhibits the binding of basic fibroblast growth factor to cultured human aortic SMCs. Lake and Castellot (41) showed that Wnt-induced secreted protein-2 modulates the antiproliferative effect of heparin and regulates cell motility in VSMCs.…”

Pharmacology of Heparin and Related Drugs

“…Interactions between heparin and proteins can vary from highly sequence specific, such as the binding of AT, to relatively nonspecific (Mulloy et al, 1996) (see section III); hence, a wide array of physiologically relevant molecules are bound by this highly polyanionic molecule (Tyrrell et al, 1999; Table 1). A significant number of proteins that can be classed as heparin binding are fundamentally associated with the inflammatory response, including, but by no means limited to, cytokines (Muramatsu and Muramatsu, 2008), chemokines (Miller and Krangel, 1992;Handel et al, 2005;Shute, 2012), growth factors (Skinner et al, 1991;Watt et al, 1993;Diamond et al, 1995;Bono et al, 1997;Koenig et al, 1998), adhesion molecules (Lever et al, 2000), cytotoxic peptides (Fredens et al, 1991), and tissue-degrading enzymes (Redini et al, 1988;Walsh et al, 1991).…”