Mechanisms by Which miR-584-5p Regulates Osteogenic Differentiation and Inflammation in Human Dental Pulp Stem Cells.

BACKGROUND: The pathological characteristic of pulpitis is inflammatory damage to the dental pulp tissue. OBJECTIVES: Investigating the function of miR-584-5p in osteogenic differentiation and inflammatory responses of human dental pulp stem cells (hDPSCs). METHODS: A total of 60 inflamed dental pulp tissue samples were collected from irreversible pulpitis patients, along with 40 healthy dental pulp tissue samples obtained from patients undergoing orthodontic treatment. Osteogenic differentiation models were established using hDPSCs, and an in vitro inflammatory model was induced by lipopolysaccharide treatment. miRNA and mRNA expression were measured using RT-qPCR. Cell proliferation was assessed via the CCK-8 assay, while the dual-luciferase assay was employed to confirm the targeted relationship. Western blot analysis was employed to assess the expression level of phosphatase and tensin homolog (PTEN) protein. The protein contents of inflammatory factors and osteogenic-related markers such as alkaline phosphatase, runt-related transcription factor 2, osteocalcin, dentin sialophosphoprotein, and dentin matrix protein 1 were detected by enzyme-linked immunosorbent assay. RESULTS: In inflamed dental pulp tissue, miR-584-5p was significantly upregulated, while PTEN was significantly downregulated, and the two showed a negative correlation. Overexpression of miR-584-5p could inhibit the hDPSCs' osteogenic differentiation and aggravate the lipopolysaccharide-induced inflammatory response. In contrast, inhibition of miR-584-5p exerted the opposite effects: promoting osteogenic differentiation and alleviating the inflammatory response. PTEN was a direct target gene of miR-584-5p. Overexpression of PTEN could reverse, to a certain extent, the inhibitory effect of miR-584-5p overexpression on osteogenic differentiation and its proinflammatory effect. Conversely, knockdown of PTEN could weaken, to a certain extent, the osteogenic promotion and anti-inflammatory effects caused by miR-584-5p inhibition. CONCLUSION: miR-584-5p was highly expressed in pulpitis and exerted dual regulatory effects on hDPSCs by inhibiting their osteogenic differentiation and promoting their inflammatory response, through direct targeting and suppression of PTEN.