7-ketocholesteryl-9-carboxynonanoate induced nuclear factor-kappa B activation in J774A.1 macrophages

Aims: 7-Ketocholesteryl-9-carboxynonanoate (oxLig-1), a lipid moiety of oxidized low-density lipoprotein (oxLDL), has been reported to be a crucial ligand of beta2-glycoprotein I (β(2)-GPI), and plays a potential role in the development of atherosclerosis (AS), however, the role of the sole oxLig-1 in the development of AS remains unclear.

Main methods: Expression and phosphorylation levels of several proteins, such as nuclear factor-kappaB (NF-κB), protein kinase C (PKC), IκBα and inter-cellular adhesion molecule 1 (ICAM-1) were determined by Western blot; nuclear localization of NF-κB was studied by immunocytochemistry; NF-κB activation was assayed by electrophoretic mobility shift assay (EMSA); and expressions of genes associated with AS process were investigated by Mouse Atherosclerosis RT(2) Profiler PCR Array assay.

Key findings: The present work indicated that oxLig-1 induced IκBα phosphorylation and results in the nuclear translocation of NF-κB in J774A.1 macrophages. Moreover, oxLig-1-induced NF-κB DNA binding activity was detected by EMSA. Indeed, oxLig-1 led to the activation of PKC prior to activating NF-κB. The treatment of oxLig-1 in J774A.1 macrophages up-regulates the expression of NF-κB target genes including ICAM-1.

Significance: OxLig-1 on the oxLDL plays an important role in AS process, as evidenced by the NF-κB activation and up-regulation of genes involved in AS development in oxLig-1 challenged J774A.1 macrophages.