Abstract 16748: Induction of Hypercholesterolemia and Atherosclerosis in Mice by Adeno-Associated Viral Vectors Encoding the PCSK9 Gene
Background: Induction of advanced atherosclerosis in small animals has mostly been achieved in germline genetically modified mice, such as apolipoprotein E or LDL receptor deficient mice. However, the need to breed with these lines for genetic experiments is time consuming and inefficient, and initiation of the disease from birth constrains the types of experiments that can be performed. New techniques to induce atherosclerosis in the strain of choice and at the time point of choice are therefore needed.
Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibits LDL receptor recycling, and gain-of-function PCSK9 mutations, e.g. D374Y, cause accelerated atherosclerosis in humans.
We assessed the hypothesis that virus-mediated gene transfer of D374Y-PCSK9 could induce atherosclerosis in mice.
Methods: We constructed a recombinant adeno-associated virus encoding human D374Y-PCSK9 (rAAV-D374Y-PCSK9). C57BL/6NTac mice were given a single intravenous dose of the virus (5х10^11, 1х10^11, or 2х10^10 viral genomes) and then fed a high-fat diet with or without added cholate for 12 weeks (n=4 in each of the 6 groups). D374Y-PCSK9 and total cholesterol (TC) levels were measured in plasma, and atherosclerosis was quantified en face.
Results: Plasma D374Y-PCSK9 levels increased rapidly after rAAV-D374Y-PCSK9 injection. Twenty-one days after injection the low-dose group fed a cholate-containing diet had a 13-fold higher TC compared with controls, and the high-dose group a 17-fold higher TC. In the cholate-free groups TC was 4-fold higher in the low-dose group and 6-fold higher in the high-dose group.
Both D374Y-PCSK9 and TC levels remained strongly elevated throughout the study period. At the end of the study all the vector-injected groups showed development of atherosclerotic lesions in the aorta, whereas control groups showed no lesion development. Cross-section histology of the aortic root revealed presence of fibroatheromas in all vector-injected groups.
Conclusion: We found that a single dose of rAAV-D374Y-PCSK9 induced hypercholesterolemia and atherosclerosis in mice. This technique may be used as a quick and versatile tool for atherosclerosis research in mice, but may also in perspective be applicable in other small animal species.
- © 2013 by American Heart Association, Inc.