p66^Shc Deletion Confers Vascular Protection in Advanced Atherosclerosis in Hypercholesterolemic Apolipoprotein E Knockout Mice

Abstract

Previous studies showed that p66^{Shc −/−} mice on a very-high-fat diet (HFD) had reduced oxidative stress, foam cell, and early atherosclerotic lesion formation. Here, the authors have used hypercholesterolemic apolipoprotein E (ApoE^−/−) mice to investigate the role of p66Shc deletion in advanced atheroma. The authors generated mice deficient of both ApoE and p66Shc genes (ApoE^−/− /p66^{Shc −/−}). They used microsatellite polymerase chain reaction (PCR) analysis to analyze the genetic background and considered only animals with a constant percentages of C57B6L and 129SV background strands (it was obtained the 50.3% ± 6.4% of C57B6L background). Computer-assisted analysis revealed that advanced atherosclerotic lesions in ApoE^−/−/p66^{Shc +/+} were significantly larger than those observed in ApoE^−/−/p66^{Shc −/−}. Accordingly, the lipid-laden macrophage foam cells and oxidation-specific epitopes in ApoE^−/−/p66^{shc +/+} HFD-treated groups were higher than those observed in normal diet (ND)-treated groups. Thus, p66^{Shc −/−} plays an important protective role also against advanced atherosclerotic lesion formation. Finally, the authors have used microarray to investigate major changes in gene expression in aortas of mice with ApoE^−/−/p66^{Shc −/−} background treated with a very HFD in comparison to ApoE^−/−/p66^{Shc +/+} (these data have been confirmed by by real-time PCR and immunohistochemistry). DAVID (Database for Annotation, Visualization and Integrated Discovery) analysis revealed that CD36 antigen (CD36), tissue inhibitor of metalloproteinase 2 (TIMP2), apolipoprotein E (ApoE), acetyl–coenzyme A acetyltransferase 1 (ACAT1), and thrombospondin 1 (THBS1) can be involved in p66 deletion–dependent vascular protection through the adipocytokine/lipid signaling pathway.

Keywords:

• Atherosclerosis
• ApoE
• p66^Shc