MicroRNA-146a sponge therapy suppresses neointimal formation in rat vein grafts

The long-term failure of vein grafts due to neointimal hyperplasia remains a difficult problem in cardiovascular surgery. Exploring novel approaches to prevent neointimal hyperplasia is important. MicroRNA-146a (miR-146a) plays an essential role in promoting vascular smooth muscle cell (VSMC) proliferation. Thus, the aim of the present study is to investigate whether adenovirus-mediated miR-146a sponge (Ad-miR-146a-SP) gene therapy could attenuate neointimal formation in rat vein grafts. (Ad-miR-146a-SP) was constructed to transfect cultured VSMCs and grafted veins. To improve the efficiency of transferring the miR-146a sponge gene into the grafted veins, 20% poloxamer F-127 gel incorporated with 0.25% trypsin was used to increase adenovirus contact time and penetration. miR-146a-SP transduction significantly reduced the expression of miR-146a both in cultured VSMCs and vein grafts. miR-146a sponge markedly attenuated VSMC proliferation and migration. Consistent with this, miR-146a sponge gene therapy significantly attenuated neointimal formation and also improved blood flow in the vein grafts. Mechanistically, we identified the Krüppel-like factor 4(KLF4) as a potential downstream target gene of miR-146a in vein grafts. Our data show that miR-146a sponge gene therapy could effectively reduce miR-146a activity and attenuate neointimal formation in vein grafts, suggesting its potential therapeutic application for prevention of vein graft failure. © 2018 IUBMB Life, 71(1):125-133, 2019.