title: Removal of heparan sulfate by heparinase treatment inhibits FGF-2-dependent smooth muscle cell proliferation in injured rat carotid arteries.
abstract: Smooth muscle cells (SMC) of the rat carotid arterial media proliferate and migrate in response to injury during the formation of a neointima. The interaction of fibroblast growth factor (FGF-2), which is released at the site of injury, with heparan sulfate proteoglycans (HSPGs) is necessary to induce signaling, which elicits an FGF-dependent mitogenic response by arterial smooth muscle cells, and also serves as a mechanism for storage of the growth factor within the extracellular matrix. However, whether these interactions are critical during neointimal formation has not been directly tested. In this study, a model of FGF-2-dependent medial SMC mitogenic response in balloon-injured rat carotid artery was used to test the effect of degradation of vessel wall heparan sulfate on subsequent SMC proliferation. Treatment of balloon-catheterized rat carotid arteries with chondroitin ABC lyase and/or heparin lyases eliminated heparan sulfates in the vessel wall, as determined by immunoperoxidase staining. In contrast, the distribution in the carotid vessel wall of the large core protein of perlecan, a major vessel wall HSPG that binds FGF-2, is not decreased. The effect of glycosaminoglycan digestion in situ on medial SMC proliferation in response to a bolus injection of FGF-2 after injury was determined by measuring the percentage of SMC nuclei that incorporated 5-bromo-2'-deoxyuridine (BrdU) 48 h after injury. Enzymatic removal of heparan sulfate reduced BrdU incorporation into medial SMC by 60-70% (P < 0.001) at 48 h after injury. Moreover, pre-incubation of FGF-2 with heparin prior to injection restored SMC replication to the levels present in injured vessels treated with buffer alone (P < 0.01). These experiments indicate that endogenous HSPGs are essential to promote FGF-2-driven medial SMC proliferation following injury, and that heparinase treatment can abrogate FGF-2-dependent responses in vivo.
authors.affiliation: The Hope Heart Institute, 1124 Columbia Street, Suite 783, Seattle, WA 98104, USA. mkinsella@hopeheart.org
authors.forename: Michael G
authors.initials: MG
authors.lastname: Kinsella
authors.forename: Colleen
authors.initials: C
authors.lastname: Irvin
authors.forename: Michael A
authors.initials: MA
authors.lastname: Reidy
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Wight
mesh_terms: D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D002339:Carotid Arteries / Q000378:metabolism / Q000473:pathology*; D020212:Carotid Artery Injuries / Q000378:metabolism / Q000473:pathology; D002404:Catheterization; D002455:Cell Division / Q000187:drug effects*; D019765:Chondroitin ABC Lyase / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000293:injuries / Q000473:pathology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology / Q000502:physiology*; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism; D019763:Heparin Lyase / Q000494:pharmacology; D006497:Heparan Sulfate / Q000378:metabolism*; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D009131:Muscle, Smooth, Vascular / Q000293:injuries / Q000378:metabolism / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001973:Bromodeoxyuridine; D019765:Chondroitin ABC Lyase; D016222:Fibroblast Growth Factor 2; D019812:Heparan Sulfate Proteoglycans; D019763:Heparin Lyase; D006497:Heparan Sulfate; C071927:perlecan