Delivery and expression of fluid shear stress-inducible promoters to the vessel wall: Applications for cardiovascular gene therapy

In atherosclerosis, endothelial cells at sites of stenosis experience elevated levels of shear stress. We have constructed a series of shear stress-inducible transcription units (SITUs) expressing the luciferase reporter gene and determined their activation by fluid shear stress in transfected endothelial cells. Chimeric promoters were constructed that comprised basal transcription factor-binding sites coupled to a shear stress response element (SSRE). We have used consensus binding sites for transcription factors NF-kappa B, Ap1, Sp1, Oct1, and Egr-1/Sp1 in either the presence or absence of the previously defined "GAGACC" SSRE, The response of the promoters to shear stress was determined after transfection into:human umbilical vein endothelial cells (HUVECs), After transient transfection into HUVECs, fluid shear stress activated the promoters by between two- and eightfold. The most responsive SITUs comprised an overlapping Sp1/Egr-1-binding site linked to a TATA box with (SP5) or without (SP7) the GAGACC SSRE, Instillation of SP5 DNA in vivo into the left carotid artery of rabbit and subsequent generation of a stenosis:using a mechanical wire occluder caused a 10-fold upregulation of luciferase reporter gene expression at the site of vessel occlusion, These vectors show promise for therapeutic gene expression at sites of occlusive vascular disease.