Affiliation: School of Dentistry, Department of Endodontics
MicroRNAs (miRNA) regulate the synthesis of cytokines in response to Toll-like receptor (TLR) activation. miRNA-181 is differentially expressed in pulpitis, which represents an immune reaction to bacteria and is also the most common cause of emergency room visits due to dental pain. We employed an in-vitro model to determine the role of miRNA in pulpitis, which has been shown in several studies to overexpress Interleukin-8 (IL-8). Primary human dental pulp fibroblasts (HDPF) were stimulated with the TLR-2/4 agonist P. gingivalis lipopolysaccharide. An inversely proportional relationship between IL-8 and miRNA-181a was observed, which was validated by in-silico identification of a miR-181a binding site on the 3'UTR of IL-8 and by dual-luciferase assays. This is the very first report demonstrating miR-181a regulation of IL-8. Considering that both mir-181 and IL-8 have been implicated in various systemic conditions, the findings of this study extend well beyond the confines of Endodontics.