Serum Amyloid a Promotes Visfatin Expression in Macrophages

Visfatin has been reported to exert an important role in the development of atherosclerosis. However, the mechanism that regulated the expression of Visfatin has not been elucidated yet. This study aimed to investigate the effect of SAA on the regulation of Visfatin, as well as the potential pathway. After RAW264.7 macrophages and primary monocytes were stimulated with SAA, the mRNA and protein expression of Visfatin was detected with real-time PCR and western blot, respectively. The concentration of Visfatin in the supernatant was measured with ELISA. Formyl peptide receptor 2 (FPR2) agonist (WKYMVm) and inhibitor (WRW(4)), extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor (PD98059), and peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist (Rosiglitazone) and inhibitor (GW9662) were used to investigate the mechanism of regulation of Visfatin. The results demonstrated that SAA upregulated Visfatin expression in cultured RAW264.7 macrophages and in the primary monocytes. WRW(4) decreased SAA-induced Visfatin production, while WKYMVm could induce Visfatin expression. PD98059 reduced SAA-induced Visfatin production. What is more, GW9662 inhibited SAA-induced Visfatin production, while Rosiglitazone promoted Visfatin expression. These results demonstrate that SAA upregulates Visfatin expression via a FPR2/ERK1/2/PPAR-γ signaling pathway.