LncRNA XIST knockdown ameliorates oxidative low-density lipoprotein-induced endothelial cells injury by targeting miR-204-5p/TLR4.

Oxidative low-density lipoprotein (ox-LDL)-induced endothelial cell injury is a key contributor to atherosclerosis development. However, the role and mechanism of long noncoding RNA X-inactive specific transcript (XIST) in atherosclerosis remain largely unknown. The ox-LDL-induced human umbilical vein endothelial cells (HUVECs) injury was analyzed by cell viability, apoptosis, inflammatory cytokines secretion and oxidative stress. The expression levels of XIST, microRNA-204-5p (miR-204-5p) and toll-like receptor 4 (TLR4) were detected by quantitative real-time polymerase chain reaction and western blot, respectively. The target interaction between miR-204-5p and XIST or TLR4 was explored by bioinformatics analysis, luciferase assay and RNA immunoprecipitation. The expression of XIST was enhanced in ox-LDL-treated HUVECs. Knockdown of XIST attenuated ox-LDL-induced viability inhibition, apoptosis production, inflammatory response and oxidative stress in HUVECs. XIST was validated as a sponge of miR-204-5p and TLR4 acted as a target of miR-204-5p. Knockdown of miR-204-5p reversed silence of XISTmediated suppressive role in ox-LDL-induced injury. TLR4 alleviated miR-204-5p-mediated inhibitive effect on ox-LDL-induced injury. Moreover, XIST could regulate TLR4 expression by sponging miR-204-5p. In conclusion, silence of XIST displayed a protective role in ox-LDL-induced injury in HUVECs by regulating miR-204-5p/TLR4 axis, providing a novel mechanism for understanding the pathogenesis of atherosclerosis.