Heparin selectively inhibits the transcription of tissue-type plasminogen activator in primate arterial smooth muscle cells during mitogenesis

• Published in: The Journal of biological chemistry 1992-02, Vol.267 (5), p.3438-3444
• Main Authors: TIN AU, Y. P, KENAGY, R. D, CLOWES, A. W
• Format: Article
• Language: English
• Subjects: Animals; Aorta - cytology; Aorta - drug effects; Aorta - enzymology; Biological and medical sciences; Cell Nucleus - drug effects; Cell Nucleus - physiology; Cell physiology; Cells, Cultured; DNA Replication - drug effects; Fundamental and applied biological sciences. Psychology; Genes, fos - drug effects; Genes, myc - drug effects; Glycosaminoglycans - pharmacology; Heparin - pharmacology; Isoquinolines - pharmacology; Kinetics; Mitotic Index - drug effects; Molecular and cellular biology; Muscle, Smooth, Vascular - cytology; Muscle, Smooth, Vascular - drug effects; Muscle, Smooth, Vascular - enzymology; Papio; Platelet-Derived Growth Factor - genetics; primates; Protein Kinase C - antagonists & inhibitors; Receptors, Cell Surface - genetics; Receptors, Platelet-Derived Growth Factor; Responses to growth factors, tumor promotors, other factors; RNA, Messenger - genetics; S Phase - drug effects; Sulfonamides; Tetradecanoylphorbol Acetate - pharmacology; Tissue Plasminogen Activator - genetics; Transcription, Genetic - drug effects
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)50750-5

How heparin inhibits vascular smooth muscle cell proliferation and migration has not been established. We have investigated the hypothesis that heparin inhibits vascular smooth muscle cell proliferation and migration by interfering with the expression and activity of proteases such as plasminogen activators. In an in vitro mitogenesis model, tissue-type plasminogen activator (tPA) mRNA and protein increase in baboon smooth muscle cells stimulated with fetal bovine serum or phorbol esters. Heparin inhibits smooth muscle cell proliferation and suppresses the induction of tPA mRNA and protein while it has little effect on the mRNA of urokinase-type plasminogen activator, plasminogen activator inhibitor type I, and a number of genes that are also modulated by serum and phorbol esters. The inhibitory effect on tPA mRNA is specific to heparin-like molecules and does not depend on the anticoagulation activity of heparin. The increase in tPA mRNA is due to increased transcription, which is suppressed by heparin. The induction of tPA by serum and phorbol esters is diminished by protein kinase C inhibitors such as H7 or staurosporine and by protein kinase C depletion. Since heparin suppresses the induction of the tPA gene by phorbol esters, these results suggest that heparin may interfere with the protein kinase C pathway.