Thrombin Stimulates Smooth Muscle Cell Procollagen Synthesis and mRNA Levels via a PAR-1 Mediated Mechanism

Summary

Thrombin is a serine protease involved in haemostasis which exerts a number of cellular effects, including stimulating mesenchymal cell migration, proliferation, and has been implicated both in normal wound healing and pathological conditions associated with hyperproliferation of smooth muscle cells such as atherosclerosis and restenosis. We hypothesize that thrombin, in addition to its proliferative effects, may also influence the deposition of matrix proteins at sites of vascular injury by directly stimulating smooth muscle cell procollagen production.

10 nM thrombin significantly stimulated rat aortic smooth muscle cell procollagen production by 34 ± 3% compared to media control cells over a 48 h incubation period, and increased steady state α₁(I) pro-collagen mRNA levels by up to 104 ± 22%. These effects are mediated via interaction of thrombin with the PAR-1 receptor since TRAP (Thrombin Receptor Activating Peptide) stimulated procollagen production by 23 ± 0.5%. In addition, conditioned medium from thrombin-treated cells stimulated procollagen production by 30 ± 3% suggesting that thrombin is acting via the production and/or release of an autocrine mediator.

These data suggest a novel role for thrombin in vascular wound healing and the development of pathological conditions associated with increased connective tissue deposition.

• References

• 1 Carney DH. Postclotting effects of thrombin mediated by interaction with high affinity receptors. In: Thrombin structure and function. Berliner L. ed. Plenum; New York, NY: 1992. pp 351-96.
• 2 Grand RJA, Turnell AS, Grabham PW. Cellular consequences of thrombin-receptor activation. Biochem J 1996; 313: 353-68.
• 3 Bar-Shavit R, Benezra M, Eldor A, Hy-Am E, Fenton II JW, Wilner GD, Vlodavsky I. Thrombin immobilized to extracellular matrix is a potent mitogen for vascular smooth muscle cells: nonenzymatic mode of action. Cell Reg 1990; 1: 453-63.
• 4 Ross R. The pathogenesis of atherosclerosis – an update. N Eng J Med 1986; 314: 488-500.
• 5 Fingerle J, Johnson R, Clowes AW, Majesky MW, Reidy MA. Role of platelets in smooth muscle cell proliferation and migration after vascular injury in rat carotid artery. PNAS 1989; 86: 8412-6.
• 6 Nelken NA, Soifer SJ, O’Keefe J, Vu TKH, Charo IF, Coughlin SR. Thrombin receptor expression in normal and atherosclerotic human arteries. J Clin Invest 1992; 90: 1614-21.
• 7 Wilcox JN, Rodriguez J, Subramanian R, Ollerenshaw J, Zhong C, Hayzer DJ, Horaist C, Hanson SR, Lumsden A, Salam TA, Kelly AB, Harker LA, Runge M. Characterization of thrombin receptor expression during vascular lesion formation. Circ Res 1994; 75: 1029-38.
• 8 Strauss BH, Chisholm RJ, Keeley FW, Gotlieb AI, Logan RA, Armstrong PW. Extracellular matrix remodeling after balloon angioplasty injury in a rabbit model of restenosis. Circ Res 1994; 75: 650-8.
• 9 Chambers RC, McAnulty RJ, Shock A, Campa JS, Newman Taylor A J, Laurent GJ. Cadmium selectively inhibits fibroblast procollagen production and proliferation. Am J Physiol 1994; 267: L300-L8.
• 10 Graham DJ, Alexander JJ. The effects of thrombin on bovine aortic endothelial and smooth muscle cells. J Vasc Surg 1990; 11: 307-13.
• 11 Ohba T, McDonald JK, Silver RM, Strange C, LeRoy EC, Ludwicka A. Scleroderma bronchoalveolar lavage fluid contains thrombin, a mediator of human lung fibroblast proliferation via induction of platelet-derived growth factor alpha-receptor. Am J Respir Cell Mol Biol 1994; 10: 405-12.
• 12 Stouffer GA, Sarembock IJ, McNamara CA, Gimple LW, Owens GK. Thrombin-induced mitogenesis of vascular SMC is partially medicated autocrine production of PDGF-AA. Am J Physiol 1993; 265: C806-C11.
• 13 Herbert JM, Dupuy E, Laplace MC, Zini JM, Bar-Shavit R, Tobelem G. Thrombin induces endothelial cell growth via both a proteolytic and a nonproteolytic pathway. Biochem J 1994; 303: 227-31.
• 14 Bachhuber BG, Sarembock IJ, Gimple LW, Owens GK. Alpha-thrombin induces TGF 1 mRNA and protein in cultured vascular smooth muscle cells via a proteolytically activated receptor. J Vasc Res 1997; 34: 41-8.
• 15 Taipale J, Koli K, and Keski-Oja J. Release of transforming growth factor-1 from the pericellular matrix of cultured fibroblasts and fibrosarcoma cells by plasmin and thrombin. J Biol Chem 1992; 267: 25378-84.
• 16 Ishihara H, Connolly AJ, Zeng D, Kahn ML, Zheng YW, Timmons C, Tram T, and Coughlin SR. Protease-activated receptor 3 is a second thrombin receptor in humans. Nature 1997; 386: 502-6.
• 17 Reidy MA. Biology of a disease: a reassessment of endothelial injury and arterial lesion formation. Lab Invest 1985; 53: 513.
• 18 Fager G. Thrombin and proliferation of vascular smooth muscle cells. Circ Res 1995; 77: 645-50.
• 19 Badimon L, Meyer BJ, Badimon JJ. Thrombin in arterial thrombosis. Haemostasis 1994; 24: 69-80.
• 20 Brown SL, Lundgren CH, Nordt T, Fujii S. Stimulation of migration of human aortic smooth muscle cells by vitronectin: implications for atherosclerosis. Cardiovasc Res 1994; 28: 1815-20.
• 21 Noda-Heiny H, Sobel BE. Vascular smooth muscle cell migration mediated by thrombin and urokinase receptor. Am J Physiol 1995; 268: C1195-C201.
• 22 Ragosta M, Barry WL, Gimple LW, Gertz SD, McCoy KW, Stouffer GA, McNamara CA, Powers ER, Owens GK, Sarembock IJ. Effect of thrombin inhibition with desulfatohirudin on early kinetics of cellular proliferation after balloon angioplasty in atherosclerotic rabbits. Circulation 1996; 93: 1194-200.