Dual impacts of lncRNA XIST and lncRNA SNHG5 on inflammatory reaction and apoptosis of endothelial cells via regulating miR‐155/CARHSP1 axis

Considering the significance of lncRNA/miRNA axis in explaining atherosclerosis (AS) progression, this investigation was intended to clarify whether lncRNAs XIST/SNHG5 would regulate AS aetiology by sponging miR-155, an AS-promoting molecule. We altogether recruited 367 patients who were examined by coronary angiography, and meanwhile, human coronary artery endothelial cells (HCAECs) were purchased to establish cells models via ox-LDL treatment. The study results indicated that lowly expressed XIST/SNHG5 and highly expressed miR-155 were frequently detectable among AS patients who showed severe stenosis and possessed high triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-sensitivity C-reactive protein (hs-CRP) levels. Besides, HCAECs treated by ox-LDL released large amounts of inflammatory cytokines, and their apoptosis rate was also raised. Moreover, expressions of XIST and SNHG5 declined markedly within ox-LDL-treated HCAECs, whereas miR-155 expression significantly ascended. Transfection of pcDNA-XIST and pcDNA-SNHG5 both reduced the expression of TNF-alpha, IL-6, IL-8 and IL-1 beta within HCAECs and also dampened the apoptotic tendency of HCAECs. Co-treatment of pcDNA-XIST and pcDNA-SNHG5 produced a larger effect on HCAEC activity than pcDNA-XIST or pcDNA-SNHG5 alone. Furthermore, miR-155, modified by XIST and SNHG5, was capable of reversing the impacts of XIST and SNHG5 on HCAEC activity. Eventually, CARHSP1 was activated by XIST and SNHG5, and its overexpression dwindled impacts of miR-155 mimic on proliferation and inflammation response of HCAECs. In conclusion, targeting XIST and SNHG5 might be an ideal alternative in delaying AS progression, allowing for their repression of downstream miR-155.