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Background: Thrombospondin-1 (TSP-1) stimulates vascular smooth muscle cell (VSMC) migration via defined intracellular signaling pathways. The aim of this study was to examine the signaling pathways whereby TSP-1 folded domains (amino-terminal [NH(2)], procollagen homology [PCH], all 3 type 1 repeats [3TSR], and a single recombinant protein containing the 3rd type 2 repeat, the type 3 repeats, and the carboxyl-terminal [E3T3C1]) induce VSMC migration., Methods: Quiescent VSMCs were pretreated with serum-free media or inhibitors: PP2 (c-Src), LY294002 (phosphatidylinositol 3-kinase), FPT (Ras), Y27632 (Rho kinase), SB202190 (p38 kinase), and PD98059 (extracellular signal-regulated kinase). Migration induced by serum-free media, TSP-1, NH(2), PCH, 3TSR, and E3T3C1 was assessed using a modified Boyden chamber., Results: TSP-1, NH(2), 3TSR, and E3T3C1 induced VSMC chemotaxis (P < .05), but PCH did not (P > .05). PP2, FPT, SB202190, and PD98059 attenuated chemotaxis stimulated by TSP-1, NH(2), 3TSR, and E3T3C1 (P < .05). LY294002 inhibited TSP-1-induced and E3T3C1-induced (P < .05) but not NH(2)-induced or 3TSR-induced (P > .05) chemotaxis. Y27632 inhibited NH(2)-induced, 3TSR-induced, and E3T3C1-induced (P < .05) but not TSP-1-induced (P > .05) induced chemotaxis., Conclusions: TSP-1 folded domains are differentially dependent on intracellular signaling pathways to induce migration., (Published by Elsevier Inc.)

Background: Vascular smooth muscle cell (VSMC) migration is an important process in many vascular disorders. Nicotine, thrombospondin-1 (TSP-1) and fibronectin (Fn) separately induce VSMC migration. The hypothesis of this study was that nicotine treatment of vascular cells would augment TSP-1-induced and Fn-induced VSMC migration., Methods: VSMCs or endothelial cells (ECs) were treated with serum-free medium or nicotine. Migration of VSMCs was assessed using a modified Boyden chemotaxis chamber to serum-free medium, TSP-1, Fn, EC basal medium, and conditioned EC medium or nicotine-treated conditioned EC medium alone or with supplemented TSP-1 or Fn., Results: Nicotine treatment increased VSMC chemotaxis to serum-free medium, but TSP-1 or Fn had no further effect on chemotaxis. Conditioned EC and nicotine-treated conditioned EC enhanced VSMC chemotaxis, which was further augmented by Fn supplementation., Conclusions: Nicotine-stimulated EC derived factors induce VSMC migration, which is augmented by the addition of Fn., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: Neointimal hyperplasia involves the migration of medial vascular smooth muscle cells (VSMCs) in response to arterial injury. Thrombospondin-1 (TSP1), platelet-derived growth factor (PDGF), and fibronectin (Fn) induce VSMC migration. Nitric oxide (NO) limits VSMC migration. The hypothesis of this study is that NO would dose dependently inhibit TSP1-induced, PDGF-induced, and Fn-induced VSMC chemotaxis., Methods: VSMCs were pretreated with serum free media or the NO donors diethylenetriamine NONOate or S-nitroso-N-acetyl-D,L-penicillamine. Chemotaxis to TSP1, PDGF, or Fn was determined. Analysis of variance with post hoc testing was done. P values < .05 were considered significant., Results: PDGF, TSP1, and Fn induced VSMC chemotaxis. NO donors inhibited chemotaxis of VSMCs to PDGF in a concentration-dependent manner. NO donors had a variable effect on TSP1-induced chemotaxis. NO donors did not inhibit Fn-induced chemotaxis., Conclusion: The complex interactions of these proteins in vivo will need to be considered when developing NO-dependent therapies for neointimal hyperplasia., (Published by Elsevier Inc.)