Effect and mechanism of visfatin activity on EMMPRIN expression in macrophages

AIM: To investigate the effect and mechanism of visfatin on extracellular matrix metalloproteinase inducer (EMMPRIN) expression in macrophages. METHODS: Thp-1 derived macrophages were stimulated with different concentrations of visfatin. EMMPRIN mRNA and protein expression were assayed by RT-PCR and Western blot. For inhibition study, cells were pretreated with MAPK inhibitors, retinoid x receptor(RXR) ligand and nuclear transcription factor peroxisome proliferator-activated receptorγ (PPARγ) ligand prior to incubation with visfatin for 24 h. Cells were also stimulated with different concentrations of visfatin to investigate the effect of visfatin on MAPK activation and PPARγ expression. RESULTS: Visfatin significantly enhanced EMMPRIN mRNA and protein expression in macrophages. p38 and ERK1/2 MAPK inhibitors as well as RXR ligand blocked this activity. Visfatin activated p38 and ERK1/2 MAPK. CONCLUSION: Visfatin enhances macrophage expression of inflammatory factors, which require p38 and ERK1/2 MAPK. RXR may mediate this activity.