[Effects of NF-E2-related factor-2 promoter polymorphism on lipopolysaccharide-induced inflammatory responses in macrophages].

Objective: To explore the effects of NF-E2-related factor-2 (NRF2)-617C/A promoter polymorphism on NRF2 expression as well as lipopolysaccharide-induced inflammatory responses in macrophages.

Methods: NRF2-617C/A promoter fragments were synthesized by chemical method and cloned into a pUC57 vector. The dul-luciferase reporter assay was employed to determine the activity of promoters. Then recombinant adenoviral vectors were constructed and transfected into macrophages. The expression of Nrf2 was examined by Western blotting and reverse transcription (RT)-PCR. The expressions of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10) in macrophages after the stimulation of LPS were determined by enzyme-linked immunosorbent assay (ELISA).

Results: The activity of NRF2-617C promoter-luciferase reporter (FLuc/RLuc activity ratio) was significantly higher than that of NRF2-617A group (0.584 ± 0.016 vs 0.258 ± 0.018, P < 0.05).The NRF2 protein and mRNA levels in -617C group were much higher than those of 617A group (1.123 ± 0.080 vs 0.951 ± 0.057,1.889 ± 0.031 vs 1.647 ± 0.323, both P < 0.05). After the stimulation of LPS, the NRF2 protein expression in macrophages significantly increased (0.584 ± 0.016 vs 0.258 ± 0.018, P < 0.05). Compared with -617A group, there was a significantly higher expression of NRF2 in -617C group (0.671 ± 0.033 vs 0.751 ± 0.014, P < 0.05). Additionally, the productions of IL-6 and IL-10 in -617C group were markedly lower than those in -617A group as well as IL-6/IL-10 (both P < 0.05). However, no significant difference existed in the levels of TNF-α between -617C and -617A groups (P > 0.05).

Conclusions: The -617C/A promoter polymorphism of NRF2 may influence the NRF2 expression. And it appears to be associated with the LPS-induced inflammatory responses in macrophages.