Effects Of MiR-34a On Osteogenic Differentiation Of MG63 Cells In Healthy And Infected Conditions

Periodontitis is a kind of chronic inflammatory diseases.Periodontal pathogens such as Porphyromonas gingivalis(Pg)with a variety of virulence factors can stimulate the host immune response and cause alveolar bone resorption,and ultimately lead to periodontal tissue damage.It was reported that about 47% of Americans suffer from varying degrees of periodontitis and 64% for adults aged 65 years and older.Alveolar bone resorption caused by periodontitis has become the main reason for the loss of adult teeth.The harm not only severely affects chewing,pronunciation,but also affected the quality of life of patients.It is important to study the mechanism of alveolar bone resorption caused by periodontitis,inhibit the alveolar bone resorption and promote bone regeneration.Recent studies found that micro RNAs(miRNAs)were potential biomarkers and therapeutic targets for alveolar bone loss in periodontal disease.Researchers believed that alveolar bone absorption process caused by periodontitis could be affected by some miRNAs through regulating osteoclast and osteoblast function.Among these miRNAs,miR-34 a is of concern.miR-34 a,residing at 1p36,is a kind of endogenous non-coding RNA with regulatory function.Some researches found thatmiR-34 a played an important role in inflammatory response and process of bone metabolism in recent years.miR-34 a can inhibit macrophage inflammatory response induced by LPS,inhibit bone resorption,and promote the osteogenic differentiation of bone marrow mesenchymal stem cells and adipose-derived stem cells.In view of miR-34 a can promote osteogenic differentiation,inhibit LPS-induced inflammatory response and osteoclast function,we infer that miR-34 a may promote bone formation and inhibit alveolar bone absorption in inflammatory condition.Therefore,we designed this experiment to detect the effects of miR-34 a on osteogenic differentiation of osteoblast-like cells in healthy and inflammatory conditions,and laid a foundation for further study on whether miR-34 a could inhibit alveolar bone resorption caused by periodontitis.Methods:1 Human osteoblast-like cells MG63 were selected as experimental cells,and miR-34 a mimics were transfected into cells using Lipofectamine 2000.2 Fluorescence microscopy and real-time PCR were used to detect the efficiency miR-34 a transfection.3 MG63 were infected with Pg,then the expression of miR-34 a was detected by real-time PCR.4 miR-34 a mimics were used to transfect into MG63,then theexpression of Runx2,SP7 and COLⅠat the level of m RNA in MG63 under healthy and inflammatory conditions is detected by real-time PCR.Results:miR-34 a could be transfected into MG63 effectively by using Lipofectamine 2000;miR-34 a up-regulated the expression of Runx2,SP7 and COLⅠat the level of m RNA in healthy MG63;The expression of miR-34 a in MG63 was decreased in the infected condition;miR-34 a down-regulated the expression of Runx2,SP7 and COLⅠat the level of m RNA in infected MG63.Conclusion:miR-34 a can promote osteogenic differentiation of osteoblasts in healthy condition,and inhibit osteogenic differentiation of osteoblasts in infected condition.