LncRNA RP11-490M8.1 Inhibits Lipopolysaccharide-induced Pyroptosis Via TLR4/NF-κB Singling Pathway In Human Umbilical Vein Endothelial Cells

Background and aimsAtherosclerosis is known as the "No.1 killer" in developed countries,which has became the disease with the highest mortality rate and a serious threat to human health.Although the pathogenesis of atherosclerosis has not been elucidated,inflammation is one of its classic theories,which is accompanied by the whole process of atherosclerosis.Pyroptosis is a kind of programmed cell necrosis which is different from apoptosis.It depends on caspase-1 activation,then leads to cell swelling and rupture,next releases pro-inflammatory factors,and finally initiates inflammatory response.Several studies have shown that pyroptosis played an important role in atherosclerosis.However,its mechanism is still unknown.Long non coding RNA(lncRNA)has a variety of biological effects and is one of the research hotspots in recent years.It has been reported that lncRNA can regulate pyroptosis and destroy the balance of pro-inflammatory and anti-inflammatory factors,suggesting that lncRNA may participate in the development of atherosclerosis.Therefore,it is of great value to find a new target which can regulate the pyroptosis and inflammation of cells and to explore its underlying mechanism in the development of atherosclerosis.Materials and methodsFirstly,three pairs of human atherosclerotic plaque and normal arterial intima were collected,and the expression of lncRNA RP11-490M8.1 in tissues were studied by microarray analysis.Secondly,serum samples from 13 pairs of atherosclerotic patients and normal controls were collected and the expression of lncRNA RP11-490M8.1 in serum was detected by quantitative real-time polymerase chain reaction(qRT-PCR).Thirdly,Human umbilical vein endothelial cells(HUVECs)were cultured in vitro and treated with lipopolysaccharide(LPS)at different concentrations and time periods.The effect of LPS on lncRNA11-490M8.1 was studied by qRT-PCR.Then qRT-PCR and western blot were performed to investigate the effects of LPS on pyroptosis related molecules in HUVECs.Finally,qRT-PCR,western blot and lentivirus overexpression were performed to investigate the effects of lncRNA RP11-490M8.1 on pyroptosis as well as its signaling pathways.Results1.The results of qRT-PCR indicated lncRNA RP11-490M8.1 in atherosclerosis serum was markedly inhibited compared with normal serum(0.1172 times,P<0.001).2.The expression of lncRNA RP11-490M8.1 in HUVECs treated with different concentrations of LPS was significantly lower than that in the control group.Meanwhile,it was also downregulated in HUVECs treated with different times(0、12、24、48h)of LPS.3.The results of qRT-PCR and western blot demonstrated that LPS treatment at different concentrations and times could upregulate the expression of pyroptosis related molecules(Caspase-1,ASC,NLRP3,IL-1β,IL-18),as well as TLR4 and NF-κB in HUVECs.4.Overexpression of lncRNA RP11-490M8.1 significantly inhibited the expression of pyroptosis related molecules(caspase-1,ASC,NLRP3,IL-1β,IL-18)and TLR4,NF-κB.5.Overexpression of lncRNA RP11-490M8.1 could attenuate LPS induced pyroptosis and activation of TLR4 and NF-κB.ConclusionThe expression of lncRNA RP11-490M8.1 in atherosclerosis plaques and serum was significantly down regulated.LPS inhibited lncRNA RP11-490M8.1 and activated TLR4/NF-κB signaling pathway,induced pyroptosis in human umbilical vein endothelial cells.This study showed that lncRNA RP11-490M8.1 inhibited LPS induced pyroptosis through TLR4/NF-κB pathway.Therefore,lncRNA RP11-490M8.1 may provide a therapeutic target for protecting atherosclerosis.