MiR-200b attenuates IL-6 production through IKKβ and ZEB1 in human gingival fibroblasts.

OBJECTIVE

MicroRNAs (miRNAs) play important roles in biological processes such as cell differentiation, development, infection, immune response, inflammation and tumorigenesis. We previously reported that the expression of miR-200b was significantly increased in inflamed gingiva compared with non-inflamed gingiva. To elucidate the roles of miR-200b in the inflamed gingiva, we have analyzed the effects of miR-200b on the expression of IL-6 in human gingival fibroblasts (HGF).

MATERIALS AND METHODS

Total RNA and protein were extracted from HGF after stimulation by interleukin-1β (IL-1β; 1 ng/ml) or tumor necrosis factor-α (TNF-α; 10 ng/ml) and transfected with miR-200b expression plasmid or miR-200b inhibitor. IL-6, IL-1β, inhibitor of nuclear factor kappa-B kinaseβ (IKKβ), Zinc-finger E-box-binding homeobox 1 (ZEB1) and E-cadherin mRNA and protein levels were analyzed by real-time PCR and Western blot.

RESULTS

IL-1β and TNF-α increased IL-6 mRNA and protein levels, and they were significantly suppressed by miR-200b overexpression, whereas they were further increased by miR-200b inhibitor in HGF. IKKβ and ZEB1 which are target genes of miR-200b negatively regulate E-cadherin. MiR-200b suppressed the expression of IKKβ and ZEB1 and increased E-cadherin mRNA and protein levels in HGF.

CONCLUSIONS

These results suggest that miR-200b attenuates inflammatory response via IKKβ and ZEB1 in periodontal tissue.