Objective: To scrutinize the function of long non-coding RNA TUG1 on the osteogenic differentiation of human periodontal ligament stem cells in periodontitis and its specific mechanism.
Methods: Human periodontal ligament stem cells were extracted from human periodontium, followed by induction of osteogenic differentiation with osteogenic medium. Knockdown or overexpression of TUG1, microRNA-222-3p or Smad2/7 were performed in human periodontal ligament stem cells to observe their effect on expressions of osteogenic differentiation markers (Runx2, ALP, and OCN), and on calcium nodule formation by Alizarin red staining. Starbase software was utilized for prediction of the binding sites of TUG1 and microRNA-222-3p in addition to microRNA-222-3p and Smad2/7. Then dual-luciferase reporter gene assay was adopted to inspect the binding relationships between microRNA-222-3p and TUG1 or Smad2/7.
Results: Highly expressed TUG1 and lowly expressed microRNA-222-3p were found in human periodontal ligament stem cells during osteogenic differentiation. After measuring the expression of Runx2, ALP, and OCN as well as the formation of calcium nodules, we discovered that TUG1 can facilitate osteogenic differentiation of human periodontal ligament stem cells, while microRNA-222-3p had a reverse effect. Subsequently, knockdown of TUG1 and Smad2/7 or overexpression of microRNA-222-3p inhibited the osteogenic differentiation of human periodontal ligament stem cells. MicroRNA-222-3p is a target gene of TUG1, while microRNA-222-3p can negatively regulate Smad2/7.
Conclusion: LncRNA TUG1 accelerates the osteogenic differentiation of human periodontal ligament stem cells by sponging microRNA-222-3p to regulate Smad2/7.
Keywords: Human periodontal ligament stem cells; MicroRNA-222-3p; Osteogenic differentiation; Periodontitis; Smad2/7; TUG1.
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