ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
Vascular smooth muscle cell (SMC) hyperplasia is an important component in the pathogenesis of arteriosclerotic lesions and is responsible for the failure of many vascular surgical procedures. SMC proliferation is inhibited by the glycosaminoglycan heparin; however, the precise mechanisms of action are still not understood. One important question in this regard is whether binding, internalization, and metabolism of heparin are necessary for the antiproliferative activity. In this study, we have analyzed SMC rendered resistant to the antiproliferative effect of heparin by drug selection and retroviral infection of SMC. We first examined the ability of heparin to bind to SMC. Experiments using [3H]heparin indicate the presence of saturable, heparin-displaceable, protease-sensitive binding sites on both sensitive and resistant SMC. The affinity of heparin binding does not correlate with the antiproliferative response. Using fluorescent and radiolabeled heparin probes, we observed that early heparin internalization kinetics in both sensitive and resistant SMC is similar, indicating that resistanace to heparin is not due to changes in the ability of cells to take up heparin. In contrast, we observed during the continuous incubation with heparin that binding to resistant SMC is rapidly downregulated, whereas sensitive cells continue to bind and internalize heparin. These results suggest that upregulation of heparin binding to the SMC surface is required for an antiproliferative response. In an accompanying paper (Letourneur et al. [1995] J. Cell. Physiol., 165:687-695, this issue), we describe the degradation and secretion of internalized heparin in both sensitive and resistant SMC. © 1995 Wiley-Liss Inc.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1041650327
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