cyclin-d1 and Graft-Occlusion--Vascular

Toward understanding the mechanisms of vascular wall remodeling, here we have studied the role of NFATc1 in MCP-1-induced human aortic smooth muscle cell (HASMC) growth and migration and injury-induced rat aortic wall remodeling. We have identified PKN1 as a novel downstream target of NFATc1-cyclin D1/CDK6 activity in mediating vascular wall remodeling following injury. MCP-1, a potent chemoattractant protein, besides enhancing HASMC motility, also induced its growth, and these effects require NFATc1-dependent cyclin D1 expression and CDK4/6 activity. In addition, MCP-1 induced PKN1 activation in a sustained and NFATc1-cyclin D1/CDK6-dependent manner. Furthermore, PKN1 activation is required for MCP-1-induced HASMC growth and migration. Balloon injury induced PKN1 activation in NFAT-dependent manner and pharmacological or dominant negative mutant-mediated blockade of PKN1 function or siRNA-mediated down-regulation of its levels substantially suppressed balloon injury-induced smooth muscle cell migration and proliferation resulting in reduced neointima formation. These novel findings suggest that PKN1 plays a critical role in vascular wall remodeling, and therefore, it could be a promising new target for the next generation of drugs for vascular diseases, particularly restenosis following angioplasty, stent implantation, or vein grafting.

Topics: Animals; Cell Division; Cell Movement; Cyclin D1; Cyclin-Dependent Kinase 6; Enzyme Activation; Graft Occlusion, Vascular; Humans; Muscle, Smooth, Vascular; Mutation; Myocytes, Smooth Muscle; Neointima; NFATC Transcription Factors; Protein Kinase C; Rats

Proliferation of vascular smooth muscle cells (VSMCs) is a crucial event in the pathogenesis of intimal hyperplasia, the main cause of restenosis following vascular reconstruction. Here, the impact of sonic hedgehog (Shh)/Gli family zinc finger 2 (Gli2) signaling on VSMC proliferation was assessed.. Increased Shh signaling was detected in VSMCs in the neointima of vein grafts obtained from mice undergoing restenosis. Comparable results were found in primary cultured human VSMCs (hVSMCs) obtained from patients undergoing coronary bypass surgery, which were used to further assess the impacts of Shh signaling on VSMC proliferation. Inhibition of Shh signaling in hVSMCs through treatment with cyclopamine or knockdown of Gli2 results in G(1) arrest and reduced cyclin D1, cyclin E, and phosphorylated retinoblastoma (pRB) levels. In contrast, activation of Shh/Gli2 signaling in hVSMCs results in increased levels of G(1) cyclins and promotes G(1)-S transition. Stimulation of hVSMC proliferation by Shh is abolished by cyclin D1 knockdown.. Combined, these results demonstrate that Shh/Gli2 signaling stimulates VSMC proliferation via regulation of the G(1) cyclin-retinoblastoma axis and suggest that antagonists that target the Shh pathway may be therapeutically beneficial in the prevention of intimal hyperplasia.

Topics: Animals; Cell Proliferation; Cells, Cultured; Cyclin D1; Cyclin E; Disease Models, Animal; G1 Phase; Graft Occlusion, Vascular; Hedgehog Proteins; Humans; Hyperplasia; Jugular Veins; Kruppel-Like Transcription Factors; Mice; Mice, Inbred C57BL; Muscle, Smooth, Vascular; Phosphorylation; Recombinant Fusion Proteins; Retinoblastoma Protein; RNA Interference; S Phase; Saphenous Vein; Signal Transduction; Veratrum Alkaloids; Zinc Finger Protein Gli2