Effects of Homocysteine on Expression of IκB and NF-κB in Human Umbilical Endothelial Cells

Objective:To investigate the effects of homocysteine(Hcy) on the expression and activation of NF-κB in the human umbilical vein endothelial cells(HUVECs),and explore the role of Hcy in the development of atherosclerosis.Methods:The HUVECs were randomly divided into 5 groups,and each group was cultured with 0 mmol/L(control group),2.5 mmol/L Hcy(H1),5 mmol/L Hcy(H2),10 mmol/L Hcy(H3) and 15 mmol/L Hcy(H4) for 24 hours.MTT assay was used to detect the cell viability.The expression of NF-κB p65 mRNA was tested by RT-PCR,and the expression of IκB-α was detected by Western blot.The change of NF-κB p65 nuclear translation was detected by immunohistochemistry.Results:The cell viability was significantly decreased in H2,H3 and H4 compared with that of control in HUVECs(P 0.01).After HUVECs were exposed to Hcy at different concentrations,the expression of NF-κB p65 mRNA was increased significantly(P 0.05 and P 0.01),and the degradation of IκB-α protein was promoted in a concentration dependent manner.It was also found that a great deal of NF-κB p65 translated to the nucleus from cytoplasm.Conclusion:Hcy can increase the expression of NF-κB p65 mRNA obviously,and increase the degradation of IκB-α,allowing the translation of active NF-κB into the nucleus.Therefore,NF-κB regulates the expression of its target genes such as chemotatic factors and adhesion molecules,leading to the development of atherosclerosis.