Heparin-derived oligosaccharides: affinity for acidic fibroblast growth factor and effect on its growth-promoting activity for human endothelial cells.
The minimal structural requirements for the interaction of heparin with acidic fibroblast growth factor (aFGF) were investigated. Oligosaccharides (tetra- to decasaccharides) obtained by nitrous acid depolymerisation of standard heparin were separated by affinity chromatography on Sepharose-immobilised aFGF. The shortest fragment retained by the affinity column at 0.2 M NaCl and eluted at 1 M NaCl was a "regular" hexasaccharide, a trimer of the most abundant disaccharide sequence in heparin. More complex octa- and decasaccharides were also retained by the column. The oligosaccharides eluted by 1 M NaCl from the affinity column ("high-affinity" oligosaccharides) and those washed from the column at 0.2 M NaCl ("low-affinity" oligosaccharides) were compared for their capacity to protect aFGF from proteolysis and to potentiate its mitogenic activity. At a low ionic strength, all oligosaccharides tested, except the "regular" disaccharide, protected aFGF against trypsin and collagenase digestion. At higher ionic strength (greater than 0.2 M NaCl), only high-affinity oligosaccharides showed a protective effect. The high-affinity oligosaccharides (hexa- to decasaccharides) potentiated the mitogenic activity of aFGF, as measured by [3H]thymidine incorporation into DNA of human fibroblasts. The effect of the oligosaccharides on human endothelial cell proliferation was more complex: inhibition of proliferation was observed in the presence of serum and low concentrations of aFGF (1-5 ng/ml) and potentiation in the presence of higher concentrations of aFGF. The potentiating effect increased as a function of molecular size of the heparin fragments and, for a given size, as a function of the anionic charge of the oligosaccharide. Our results suggest that inhibition of cell proliferation by heparin may result from interference with an autocrine basic FGF-like activity.
Bârzu
T
T
Institut Choay, Paris Cedex.
Lormeau
J C
JC
Petitou
M
M
Michelson
S
S
Choay
J
J
D002455:Cell Division / Q000187:drug effects; D002846:Chromatography, Affinity; D004730:Endothelium, Vascular / Q000166:cytology*; D005346:Fibroblast Growth Factors / Q000378:metabolism* / Q000494:pharmacology; D006493:Heparin / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D003012:Microbial Collagenase / Q000378:metabolism; D008970:Molecular Weight; D009844:Oligosaccharides / Q000378:metabolism / Q000494:pharmacology; D000071228:Polyelectrolytes; D011108:Polymers / Q000494:pharmacology; D013329:Structure-Activity Relationship; D014357:Trypsin / Q000378:metabolism
D005346:Fibroblast Growth Factors; D006493:Heparin; D003012:Microbial Collagenase; D009844:Oligosaccharides; D000071228:Polyelectrolytes; D011108:Polymers; D014357:Trypsin