Catalytic Oligodeoxynucleotides Define a Key Regulatory Role for Early Growth Response Factor-1 in the Porcine Model of Coronary In-Stent Restenosis

Abstract

Abstract-Early growth response factor-1 (Egr-1) controls the expression of a growing number of genes involved in the pathogenesis of atherosclerosis and postangioplasty restenosis. Egr-1 is activated by diverse proatherogenic stimuli. As such, this transcription factor represents a key molecular target in efforts to control vascular lesion formation in humans.In this study, we have generated DNAzymes targeting specific sequences in human EGR-1 mRNA. These molecules cleave in vitro transcribed EGR-1 mRNA efficiently at preselected sites, inhibit EGR-1 protein expression in human aortic smooth muscle cells, block serum-inducible cell proliferation, and abrogate cellular regrowth after mechanical injury in vitro. These DNAzymes also selectively inhibit EGR-1 expression and proliferation of porcine arterial smooth muscle cells and reduce intimal thickening after stenting pig coronary arteries in vivo. Key Words: catalytic DNA Ⅲ transcription factors Ⅲ early growth response factor-1 Ⅲ stenting Ⅲ gene therapy T he capacity to selectively target specific mRNA sequences with catalytic molecules composed of DNA provides immense potential to broaden our understanding of the roles of specific mediators in normal and pathologic settings. Catalytic DNA can be used to cleave the phosphodiester linkage between virtually any unpaired purine and paired pyrimidine, selectivity being conferred by the nucleotide sequences of the hybridizing arms. These next-generation antisense oligonucleotides are extremely specific and easy to synthesize and have low toxicity, because they do not require phosphorothioate or other backbone modifications to confer nuclease resistance. DNAzyme biotechnology has practical therapeutic implications as a new category of genesuppression agents in pathophysiological settings.Stenting of coronary atherosclerotic lesions has revolutionized the treatment of cardiovascular disease in the last 5 years, after two landmark trials demonstrating a reduction in restenosis relative to coronary balloon angioplasty in comparable vessels.

Berberine suppresses MEK/ERK-dependent Egr-1 signaling pathway and inhibits vascular smooth muscle cell regrowth after in vitro mechanical injury

“…Antisense oligonucleotides or DNA enzymes targeting Egr-1 inhibited SMC proliferation after mechanic injury in vitro [6,27,30,44]. These DNA enzymes also block Egr-1 induction and neointima formation in a rat carotid angioplasty model [30] and after stenting pig coronary arteries in vivo [6]. These findings indicate that Egr-1 as a potential target gene for a therapeutic approach to inhibit neointima formation after angioplasty.…”

“…In injured vascular cells, Egr-1 is rapidly activated and found to be involved in profound chemotactic and mitogenic effects, which may contribute to the structural remodeling that typically occurs in the pathogenesis of vascular diseases [7,43]. Antisense oligonucleotides or DNA enzymes targeting Egr-1 inhibited SMC proliferation after mechanic injury in vitro [6,27,30,44]. These DNA enzymes also block Egr-1 induction and neointima formation in a rat carotid angioplasty model [30] and after stenting pig coronary arteries in vivo [6].…”

“…A dominant cellular event in the re-narrowing of the lumen after angioplasty is vascular smooth muscle cell (SMC) proliferation. Injury induces medial and then intima cell cycle reentry, following a wave of immediate early gene expression [1,6]. Cells undergo either cell proliferation, migration or both, with subsequent synthesis of extracellular matrix and collagen resulting in neointimal formation [1][2][3].…”

Egr-1 Expression During Neointimal Development in Flow-Associated Pulmonary Hypertension

“…In systemic vessels, the importance of Egr-1 expression during vascular remodeling has been confirmed given that neointima formation is reduced when Egr-1 expression is blocked. [33][34][35][36] In addition, these studies demonstrate that Egr-1-induced neointima formation is mediated through both proliferative and inflammatory pathways. [33][34][35][36] Taken together, this is the first study to demonstrate the spatiotemporal correlation between increased Egr-1 expression and increased pulmonary blood flow, as an inductor of neointimal development.…”

“…[33][34][35][36] In addition, these studies demonstrate that Egr-1-induced neointima formation is mediated through both proliferative and inflammatory pathways. [33][34][35][36] Taken together, this is the first study to demonstrate the spatiotemporal correlation between increased Egr-1 expression and increased pulmonary blood flow, as an inductor of neointimal development. These data suggest that Egr-1 may be able to initiate and maintain the process of neointimal development in flow-associated PAH and therefore also justifies further exploration of the exact role of Egr-1 in pulmonary vascular remodeling in PAH.…”