Effect of polymorphisms of Crohn disease related NOD2 gene and human beta-defensin 2 on expres-sion of human beta-defensin 2 / 中华消化内镜杂志

ABSTRACT

Objective To explore the effects of polymorphisms of Crohn's disease related NOD2 gene and human beta-defensin 2 (hBD-2) on transcription of hBD-2 gene and its mechanism. Methods HEK293T cells were transfected with hBD-2 gene and NOD2 eukaryotic expression plasmid, and were then stimulated with LPS, TNF-α, or BAY 11-7082 (antagonist of NF-κB), respectively. Transcriptional activity of hBD-2 was detected afterwards. Results LPS could suppress transcription of hBD-2 (P=0. 020), which was increased by TNF-α in a dose-dependent manner (P =0. 004). In the presence of LPS, there was sig-nificant difference in transcriptional activity of hBD-2 between wild-NOD2 transfected group and mutated NOD2 (P268S) transfected group (P=0. 008), but there was no significant difference between wild hBD-2 transfected group and mutated hBD-2 transfected group (P=0. 053). With the stimulation of TNF-α (5 ng/ml), there was a significant difference between mutated hBD-2 transfected group and wild hBD-2 transfected group (P=0. 006), but no significant difference between wild-NOD2 transfected and mutated NOD2 transfected group was defected (P = 0. 064). Pretreatment with BAY 11-7082 before TNF-α (5 ng/ml) significantly inhibited the transcriptional activity of hBD-2 (P < 0. 001). Conclusion The poly-morphism of NOD2 affects the innate expression of hBD-2, the polymorphism of site in hBD-2 promoter (-233) may lead to significant decline of the inducible expression of hBD-2, and NF-κB might be a key pathway that NOD2 protein mediates the expression of defensin.