Effect of α-pinene on nuclear translocation of NF-κB in THP-1 cells

AIM: To study the effects of α-pinene on nuclear translocation of nuclear factor-κB (NF-κB) and the expression of the inhibitor of NF-κB (IκBα) in human monocyte THP-1 cell line. METHODS: THP-1 cells were incubated with α-pinene (1, 10, and 100 mg/L, for 30 min) before being stimulated with lipopolysaccharide (LPS, 1 mg/L, 30 min). The location of NF-κB p65 subunit (NF-κB/p65) in THP-1 cells was detected by immunofluorescence and laser scanning confocal microscope (LSCM). The expression of NF-κB/p65 in nuclei and that of IκBα in cytoplasm were measured by Western-blot analysis. RESULTS: The majority of FITC-labelled NF-κB/p65 was located in the nuclei being stimulated with LPS. Whereas, no such fluorescence was seen in the nuclei of the groups pretreated with α-pinene or control cells. α-Pinene pretreatment decreased the NF-κB/p65 nuclear translocation in LPSstimulated THP-1 cells, and this effect was dose-dependent, but there was no reaction in LPS-unstimulated THP-1 cells. α-Pinene pretreatment increased IκBα protein level in cytoplasm, compared with that in LPS-stimulated THP-1 cells. CONCLUSION: In a dose-related fashion, α-pinene inhibits the nuclear translocation of NF-κB induced by LPS in THP-1 cells, and this effect is partly due to the upregulation of IκBα expression.