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. These findings demonstrate that endoluminally delivered DNAzymes targeting EGR-1 may serve as inhibitors of in-stent restenosis.
Subject(s)
Coronary Vessels/metabolism , DNA, Catalytic/pharmacology , DNA-Binding Proteins/metabolism , Graft Occlusion, Vascular/metabolism , Graft Occlusion, Vascular/prevention & control , Immediate-Early Proteins , Transcription Factors/metabolism , Animals , Cell Division/drug effects , Cells, Cultured , Coronary Vessels/drug effects , Coronary Vessels/pathology , DNA-Binding Proteins/genetics , Disease Models, Animal , Dose-Response Relationship, Drug , Early Growth Response Protein 1 , Gene Expression Regulation/drug effects , Graft Occlusion, Vascular/pathology , Humans , Muscle, Smooth, Vascular/cytology , Muscle, Smooth, Vascular/drug effects , Muscle, Smooth, Vascular/metabolism , RNA, Messenger/antagonists & inhibitors , RNA, Messenger/metabolism , Swine , Transcription Factors/genetics , Tunica Intima/drug effects , Tunica Intima/metabolism , Tunica Intima/pathologySubject(s)
Coronary Stenosis/surgery , Coronary Thrombosis/etiology , Stents/adverse effects , Ticlopidine/analogs & derivatives , Animals , Anticoagulants/therapeutic use , Aspirin/therapeutic use , Clopidogrel , Coronary Stenosis/pathology , Coronary Thrombosis/pathology , Coronary Vessels/pathology , Drug Therapy, Combination , Heparin/therapeutic use , Humans , Models, Animal , Myocardial Infarction/etiology , Myocardial Infarction/pathology , Swine , Ticlopidine/therapeutic useABSTRACT
BACKGROUND & AIMS: Activated pancreatic stellate cells have recently been implicated in pancreatic fibrogenesis. This study examined the role of pancreatic stellate cells in alcoholic pancreatic fibrosis by determining whether these cells are activated by ethanol itself and, if so, whether such activation is caused by the metabolism of ethanol to acetaldehyde and/or the generation of oxidant stress within the cells. METHODS: Cultured rat pancreatic stellate cells were incubated with ethanol or acetaldehyde. Activation was assessed by cell proliferation, alpha-smooth muscle actin expression, and collagen synthesis. Alcohol dehydrogenase (ADH) activity in stellate cells and the influence of the ADH inhibitor 4-methylpyrazole (4MP) on the response of these cells to ethanol was assessed. Malondialdehyde levels were determined as an indicator of lipid peroxidation. The effect of the antioxidant vitamin E on the response of stellate cells to ethanol or acetaldehyde was also examined. RESULTS: Exposure to ethanol or acetaldehyde led to cell activation and intracellular lipid peroxidation. These changes were prevented by the antioxidant vitamin E. Stellate cells exhibited ethanol-inducible ADH activity. Inhibition of ADH by 4MP prevented ethanol-induced cell activation. CONCLUSIONS: Pancreatic stellate cells are activated on exposure to ethanol. This effect of ethanol is most likely mediated by its metabolism (via ADH) to acetaldehyde and the generation of oxidant stress within the cells.
