miR-4485-5p regulates the progression of periodontitis by targeting CDK9

Periodontitis leads to tooth loss, affecting human oral health. The role of microRNA (miRNA) in periodontitis has received increasing attention. This study aims to explore the role of miR-4485-5p in the progression of periodontitis. Baseline clinical data were collected from 93 periodontitis participants and 85 periodontally healthy subjects. The diagnostic value of miR-4485-5p and its correlation with severity were evaluated by the ROC curve and Pearson regression. miR-4485-5p and target gene expression were detected by RT-qPCR and Western blot. The periodontitis cell model was constructed by treating hPDLSCs with P. gingivalis LPS. Cell viability and inflammatory factor levels were detected by CCK-8 and ELISA. The target genes of miR-4485-5p were identified by databases and verified by dual-luciferase reporter assay. miR-4485-5p is downregulated in the saliva of patients with periodontitis. miR-4485-5p effectively distinguishes periodontitis and is negatively correlated with plaque index (PI), bleeding index (BI), probing depth (PD), and clinical attachment level (CAL). LPS inhibits the expression of miR-4485-5p in hPDLSCs, suppresses cell proliferation, and promotes the release of TNF-α, IL-1β, IL-6, and IL-8. Overexpression of miR-4485-5p promotes cell proliferation and inhibits the secretion of inflammatory factors in LPS-induced hPDLSCs. As a target of miR-4485-5p, CDK9 reversed the effects of miR-4485-5p on cell proliferation and inflammatory factors. miR-4485-5p could be the diagnostic biomarker of periodontitis and is correlated with the severity of periodontitis. Overexpression of miR-4485-5p could reverse the cell viability and inflammation in LPS-induced hPDLSCs. While CDK9 could eliminate the effect of miR-4485-5p.