Rapamycin modulates anti- and pro-thrombotic gene expressions via Kruppel-like factor 2: in vitro studies

Abstract

Purpose: Stent thrombosis (ST) is one of severe complications after sirolimus-eluting stent (SES) implantation. However, the underlying transcriptional mechanisms of this adverse effect have less been investigated. Methods: Human umbilical vein endothelial cells (HUVECs) were treated with rapamycin and gene expression profiling including Krupple-like factor 2 (KLF2), tissue factor (TF), plasminogen activator inhibitor-1 (PAI-1), endothelial nitric oxide synthase (eNOS), thrombomodulin (TM), and mammalian target of rapamycin (mTOR) were determined. Cells infected with adenovirus-KLF2 (Ad-KLF2) were stimulated by rapamycin and the expressions of the preceding genes were also examined. At same time, the effects of cell lysates on blood clotting time were evaluated in vitro. Results: Rapamycin enhanced TF, PAI-1 but inhibited KLF2, eNOS and TM expressions in a dose-dependent manner, which were antagonized by FK-506, a competitor of rapamycin. Overexpression of KLF2 strongly reversed rapamycin-induced effects on preceding gene expressions. Meantime, KLF2 overexpression increased the time of blood clotting in vitro. Conclusion: Rapamycin resulted in an imbalance of anti- and pro- thrombotic gene expression profiling, which was reversed by overexpression of KLF2, suggesting that that the KLF2 pathway might be involved in ST after SES implantation.