Dysregulation of lncRNAs in circulation of patients with periodontitis: results of a pilot study.

BACKGROUND: Periodontitis is a chronic inflammatory disorder with a complex etiology. Long non-coding RNAs (lncRNAs) have been shown to affect pathoetiology of periodontitis. We aimed at identification of expression of five lncRNAs, namely Linc0116, Linc00667, CDK6-AS1, FENDRR and DIRC3 in the circulation and gingival tissues of these patients compared with healthy controls. METHODS: In a pilot case-control study, we compared expressions of Linc0116, Linc00667, CDK6-AS1, FENDRR and DIRC3 lncRNAs between blood and tissue samples of patients with periodontitis and healthy controls using real time quantitative PCR technique. The present work was performed on samples got from 26 patients with periodontitis and 28 controls. Female/male ratio was 16/10 and 12/16 in cases and controls, respectively. RESULTS: There was no significant difference in the expressions of Linc0116, Linc00667, CDK6-AS1, FENDRR and DIRC3 genes between affected and unaffected tissues. However, expressions of Linc0116, Linc00667, CDK6-AS1, FENDRR and DIRC3 genes were significantly lower in the blood samples of patients when compared with control samples (Ratio of mean expression = 0.16, 0.14, 0.13, 0.10 and 0.14, respectively). Subsequently, we compared expressions of these lncRNAs between patients and controls in a sex-based manner. Expressions of Linc00667, FENDRR and DIRC3 genes were significantly lower in female patients compared with female controls (RME = 0.09, 0.07 and 0.10, respectively). Yet, there was no significant difference in expression of any of mentioned lncRNAs among male subgroups. Consistent with the similar levels of Linc0116, Linc00667, CDK6-AS1, FENDRR and DIRC3 in tissue samples of patients and controls, none of them could separate these two sets of samples. However, AUC values for of Linc0116, Linc00667, CDK6-AS1, FENDRR and DIRC3 expression levels in blood samples were 0.66, 0.72, 0.70, 0.72, 0.70 and 0.68, respectively with FENDRR having the best sensitivity value. CONCLUSION: Taken together, lncRNAs might be involved in the pathologic events in the circulation of patients with periodontitis.