Heparan sulfate proteoglycans on the cell surface act as low affinity binding sites for acidic and basic fibroblast growth factor (FGF) [Moscatelli (1987): J Cell Physiol 131:123-1301 and play an important role in the interaction of FGF with the FGF receptor (FGFR). In this study, several aspects of
Heparin potentiates the action of acidic fibroblast growth factor by prolonging its biological half-life
โ Scribed by Deborah H. Damon; Roy R. Lobb; Patricia A. D'Amore; John A. Wagner
- Publisher
- John Wiley and Sons
- Year
- 1989
- Tongue
- English
- Weight
- 552 KB
- Volume
- 138
- Category
- Article
- ISSN
- 0021-9541
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โฆ Synopsis
The mechanism(s) by which heparin influences the biological activities of acidic and basic fibrc-iblast growth factors (aFGF and bFCF) is not completely understood. One mechanism by which heparin could alter the biological activities of aFGF and bFGF is by altering their biological half-lives. We investigated the possibility that heparin potentiates aFGF-induced neurite outgrowth from PC12 cells by prolonging its biological half-life. Under conditions where heparin potentiated aFGF-induced neurite outgrowth, we observed that heparin increased the biological half-life of aFGF from 7 to 39 hr. We determined that >25 hr of exposure to active aFGF was required for induction of neurite outgrowth. If aFGF activity was maintained for greater than 25 hr by periodic readdition of factor, heparin no longer potentiated aFGF-induced neurite outgrowth. These observations strongly suggest that heparin potentiates the activity of aFGF by prolonging its biological half-life. The protease inhibitors hirudin, leupeptin, and pepstatin A did not potentiate aFGF-induced neurite outgrowth, indicating that protcases inhibited by these inhibitors are not rrsponsible for the loss of aFGF activity that we observed. However, aprotinin potentiated aFGF neurite-promoting activity approximately sevenfold, indicating that proteases that are inhibited by aprotinin are at least partially responsible for aFGF inactivation. These observations suggest that heparin regulates the activity of aFGF by regulating its proteolytic degradation, thereby regulating its biological half-life.
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## Abstract The bioactivity of both bFGF and aFGF in the BALB/MKโ1 cell line has been compared to that of EGF. Our results indicate that, for that cell type, aFGF was far more potent than bFGF in inducing cell proliferation. In the presence of heparin, aFGF was as potent as EGF. In addition, excess