Association between NKILA and some apoptotic gene expression in atherosclerosis

Oxidized light-density lipoprotein (ox-LDL) causes endothelial dysfunction, which is an important determinant of atherogenesis, and subsequently leads to apoptosis. Atherosclerosis is one of the most significant cardiovascular diseases (CVDs) threatening human health and causes death worldwide. Recently, long noncoding RNAs (lncRNAs) have been suggested to involved in vascular biology. Ox-LDL activates nuclear factor kappa-B (NF-κB), and NF-κB interacting lncRNA (NKILA) inhibits NF-κB signaling. In this study, the hypothesis is that NKILA may regulate endothelial cell (EC) apoptosis and, therefore, play a role in the pathogenesis of atherosclerosis. This hypothesis is based on the knowledge that EC apoptosis contributes to atherosclerosis development and that NKILA has become a prominent lncRNA in CVDs. The expression of Bcl-2-associated X protein (BAX), caspase 9 (CASP9), cytochrome c (Cyt c, CYCS), apoptotic protease activating factor 1 (APAF1), and B-cell lymphoma 2 (BCL-2) genes in human umbilical vein endothelial cells (HUVEC) treated with ox-LDL and transfected with NKILA siRNA was analyzed using quantitative reverse transcription polymerase chain reaction (RT-qPCR). BAX, CASP9, CYCS, APAF1, and BCL-2 gene expression was downregulated in ox-LDL and NKILA siRNA-treated HUVEC. In addition, when threshold/quantification cycle (Cq) values of NKILA gene expression increased, Cq values of BAX, CASP9, APAF1, and BCL-2 gene expression increased statistics significantly. The expression detection of all these genes, resulting from NKILA gene silencing, may provide guidance for epigenetic studies on EC apoptosis in atherosclerosis.