Effects of miR-223 on expression of IL-1β and IL-6 in human gingival fibroblasts

MicroRNAs (miRNAs) are small non coding RNAs that regulate post-transcriptional expression by translational inhibition or mRNA degradation. miRNAs bind to target mRNAs through partial complementarity, and can regulate many genes. In the present study, we investigated the effects of miR-223 on the expression of inflammatory cytokines in human gingival fibroblasts (HGF). To determine the effects of miR-223 on the expressions of interleukin-1 beta (IL-1 beta) and IL-6, HGF were stimulated by IL-1 beta (1 ng/mL) or tumor necrosis factor-alpha (TNF-alpha; 10 ng/mL) and transfected with a miR-223 expression plasmid. Levels of mRNA for IL-1 beta, IL-6, inhibitor of kappa-B kinase alpha (IKK alpha) and mitogen-activated protein kinase phosphatase-5 (MKP-5) were measured by real-time PCR, and levels IL-1 beta, IL-6 and IKK alpha protein were determined by enzyme linked immunosorbent assay and Western blotting. Expression of IL-1 beta and IL-6 mRNAs was induced by IL-1 beta and TNF-alpha and further increased by miR-223 overexpression. IL-1 beta and TNF-alpha induced the expression of IL-1 beta and IL-6 mRNAs, and this was reduced by miR-223 inhibitor. Overexpression of miR-223 decreased the levels of IKK alpha protein and MKP-5 mRNA in HGF. These findings indicate that miR-223 might control the inflammatory response via IKK alpha and MKP-5 in periodontal tissue.