Objectives: The renin-angiotensin system may contribute to the pathogenesis of atherosclerosis. The transcription factor nuclear factor-kappa B (NF-kappa B) participates in most signal pathways involved in the inflammatory process. In this project the effect of angiotensin II (Ang II) on NF-kappa B activation and the promotion of PDGF-B mRNA expression in human endothelial cell line ECV304 was studied.
Methods: Electrophoretic mobility shift assay, immunofluorescence and immunoelectronic microscope techniques, including confocal microscopy and gold particle labelled electronic microscopy were applied to investigate the mechanism by which Ang II activates NF-kappa B, ECV304 cells were transiently transfected with an NF-kappa B/luciferase reporter gene and catalytically inactive NIK, IKK alpha, IKK beta mutants respectively. Northern blot was carried out to detect PDGF-B mRNA.
Results: By the findings of immunofluorescence confocal microscopy, immunoelectronic microscopy and Northern blot, Ang II was effective in stimulating NF-kappa B activation and there was definited cytoplasmic-to-nuclear translocation of NF-kappa B subunits p50 and p65 and overexpression of PDGF-B mRNA expression. Over-expression of the transiently transfected IKK alpha-KM, IKK beta-KM and NIK-KM mutant genes enabled to block the reporter gene activation induced by ang II.
Conclusion: Ang II is effective to activate NF-kappa B through a pathway dependent on NIK, IKK alpha and IKK beta, and induces PDGF-B transcription in the endothelial cell line ECV304.