Targeting Wnt/β-Catenin Activated Cells with Dominant-Negative N-cadherin to Reduce Neointima Formation

Approximately 50% of coronary artery bypass grafts using autologous saphenous vein fail within 10 years due to intimal thickening. This study examined whether a gene therapy approach that selectively kills Wnt/β-catenin/T-cell factor (TCF) activated VSMCs using dominant negative N-cadherin (dn-N-cadherin) reduced intimal thickening. Cultured human VSMCs infected with an adenovirus encoding dn-N-cadherin via the TCF promoter (Ad-TOP-dn-N-cadherin) specifically expressed dn-N-cadherin in response to activation of the Wnt/β-catenin/TCF pathway. Infection with Ad-TOP-dn-N-cadherin significantly increased VSMC apoptosis (3±0.2% vs. 9±0.7%; P<0.05, n=6), and significantly inhibited VSMC migration by 83±15% (P<0.05, n=6) but did not affect VSMC proliferation (P>0.05, n=5). In an ex-vivo human saphenous vein organ culture model, luminal delivery of Ad-TOP-dn-N-cadherin significantly increased VSMC apoptosis after seven days of culture (4±1.4% vs. 9±1.6%; P<0.01, n=6) and suppressed intimal thickening by 75±7% (P<0.05, n=5) without a detrimental effect on endothelial cell coverage. In vivo, Ad-TOP-dn-N-cadherin significantly reduced intimal thickening at day 21 (n=10) in comparison to the Ad-β-galactosidase (Ad-β-gal) control virus (n=12, P<0.05) in the mouse carotid artery ligation model. In summary, we have developed a novel approach to selectively reduce intimal thickening which may be beneficial in reducing late vein graft failure.