Atherosclerotic lower extremity peripheral artery disease (PAD) is among the most prevalent, morbid and mortal of all cardiovascular disorders. Pathologic arterial smooth muscle (ASM) cell migration is a major component of atherogenic PAD and efforts aimed at attenuating its progression are clinically essential. Cyclic nucleotide signaling has long been studied for its growth-mitigating properties in the setting of PAD and other vascular growth disorders. In this study we hypothesized that the novel, heme-independent soluble guanylyl cyclase activator BAY 60-2770 (BAY) inhibits ASM cell migration through phosphorylation of the protein kinase G (PKG) target and actin-binding protein vasodilator-stimulated phosphoprotein (VASP). In a rat model of injury-induced arterial growth, BAY significantly reduced neointima formation and luminal narrowing compared to vehicle (Veh)-treated control arteries after 2 weeks. Using rat and human ASM cells BAY significantly attenuated cell migration, reduced G:F actin, and increased cyclic GMP content, PKG activity and phosphorylated VASP at Ser239 (pVASP.S239) compared to Veh controls. Using site-directed mutagenesis, both full-length VASP-overexpressing (wild type, WT) and VASP.S239 phosphorylation-resistant mutants showed significantly reduced cell migration compared to naïve controls, however, there was no effect on cell migration between either VASP transfected group in the presence of BAY. Interestingly, both VASP mutants showed significantly increased PKG activity compared to naïve cells, and in turn pharmacologic PKG blockade in the presence of BAY fully reversed the inhibitory effect of BAY alone on cell migration. These data suggest BAY has capacity to inhibit ASM cell migration through cyclic GMP/PKG/VASP signaling yet through mechanisms independent of pVASP.S239. Findings from this study implicate BAY via cyclic GMP/PKG/VASP as a potential pharmacotherapeutic agent against aberrant ASM growth disorders such as PAD.
Effect of soluble guanylyl cyclase activator and stimulator therapy on nitroglycerin-induced nitrate tolerance in rats