Abstract 14821: Long-Term Consistent Expression of Apolipoprotein B mRNA-Specific Hammerhead Ribozymes, Delivered via scAAV8.2 Vector, Promises Atherosclerosis Inhibition in Mice
Target substrate-specific hammerhead ribozymes cleave the specific mRNA efficiently and result in the inhibition of gene expression. In humans, elevated levels of apolipoprotein B (apoB) is positively associated with premature coronary artery diseases. The goal of this study is to demonstrate that long-term reduction of apoB gene expression, using hammerhead ribozymes, would result in inhibition of atherosclerosis development. Our laboratory has previously shown that specifically designed hammerhead ribozymes cleaved apoB mRNA efficiently in HepG2 cells. For this study, we used a new designed hammerhead ribozyme targeted at the N-terminal of apoB mRNA at GUC2326 (designated RB1) as well as a previously designed ribozyme targeted at GUA6679 of apoB mRNA (designated RB15), and used scAAV8.2 vector to express active ribozymes of RB1, RB15, combination of RB1/RB15, and an inactive hammerhead ribozyme RB15-mutant in atherosclerosis prone LDb mice (Ldlr-/-Apobec1-/-), which are deficient of both LDL receptor (Ldlr-/-) and apoB mRNA editing enzyme (Apobec1-/-). At 4 months after treatment, the LDb mice had significantly decreased plasma triglyceride and apoB levels. Quantitative and histochemical analysis of the mouse aorta, collected on day 120, showed a marked decrease in the atherosclerotic lesions (RB1 decreased 64%, RB15 decreased 50% and RB1+RB15 decreased 63%). Furthermore, the active ribozymes treatment decreased the diacylglycerol acyl transferase (Dgat-1) mRNA levels and the incorporation of trans-fatty acids to diacylglycerol. These results provide the first time evidence that decreased apoB levels had significant impact on atherosclerosis development as the result of decreased Dgat-1 expression and the levels of triacylglycerol.
- © 2013 by American Heart Association, Inc.