Nox4 Participates In Apoptosis Of Endothelial Cells Induced By Homocysteine Through NLRP3 Signaling Pathway

BackgroundHomocysteine(Hcy)is one of the independent risk factors for cardiovascular disease.Hcy can induce the formation of cellular reactive oxygen species(ROS),which causes endothelial damage and leads to the development of atherosclerosis(AS).ROS in endothelial cells are mainly derived from Nox4(NADPH oxidases 4).NLRP3 is highly expressed in coronary atherosclerosis and aortic sclerosis.NLRP3 is a key mediator of IL-1 family cytokine production in AS,especially when a large amount of ROS produced in cells can cause a large amount of caspase-1 precursor to be cleaved into a biologically active caspase-1 P10 fragment,promoting downstream IL-The maturation and secretion of inflammatory factors such as 1β and IL-18 impair endothelial cell function,causing cellular inflammatory damage and apoptosis,and positive feedback aggravates vascular injury.This study focuses on the role of Nox4 in Hcy-mediated endothelial cell inflammation and apoptosis,and Hcy-induced AS provides a possible mechanism.ObjectiveTo investigate the role of NADPH oxidase 4(Nox4)in oxidative stress and apoptosis of human umbilical vein endothelial cells(HUVECs)induced by homocysteine via NLRP3/caspase-1/IL-1β pathway.Methods1.Culture HUVECs in vitro.HUVECs were treated with different concentrations of Hcy to screen for appropriate induction concentrations.2.Then the cells were divided into control group,Hcy treatment group,negative control group,siNox4 group and Hcy+ siNox4 group.3.Apoptosis rate was detected by flow cytometry;superoxide free radical level was detected by DHE staining.And Nox4 siRNA was transfected with liposome to inhibit Nox4;Western blot was used to detect the expression of Nox4,NLRP3,caspase-1 and IL-1β proteins in each group,and TUNEL was used to detect apoptosis.Results1.The expression of Nox4 in HUVECs was increased under Hcy stimulation,and the cytoplasm superoxide radicals increased,which caused oxidative stress and increased the expression of NLRP3,caspase-1,IL-1β in the protein complex inflammatory body,which eventually caused apoptosis.2.After siRNA interference inhibited Nox4,the expression of NLRP3,caspase-1 and IL-1β in HUVECs was significantly decreased by Hcy stimulation,and apoptosis was decreased.ConclusionIn endothelial cells,increased expression of Nox4 may cause endothelial damage;The inhibition of Nox4 expression to protect HUVECS from oxidative stress and apoptosis are related to the NLRP3/caspase-1/IL-1β signaling pathway of complex inflammatory bodies.