miR-155-5p can be involved in acquisition of osseointegration on titanium surface

Dental implants made of titanium are commonly used. Although titanium implants succeed by osseointegration with bone, the detailed molecular mechanism of osseointegration is unclear. To clarify the involvement of microRNA (miRNA) in the acquisition of osseointegration on titanium, here we compared the miRNA expression profiles of mouse osteoblast-like cells (MC3T3-E1) cultured on titanium-, gold-, and stainless steel-coating glass dishes by microarray analysis. Three kinds of metals, namely titanium, gold, and stainless steel, were coated on the surface of the glass dishes by sputtering with similar roughness and shape of their surface. After MC3T3-E1 cells were cultured on the dishes without coating or coating with titanium, gold, or stainless steel for 6 h, total RNA was extracted, and miRNA expression was analyzed by microarray. To confirm the expression of the selected miRNA during osteogenic differentiation of MC3T3-E1 cells, real-time PCR analysis was performed. Furthermore, the effects of selected miRNA were examined by ectopic overexpression in MC3T3-E1 cells. The microarray analysis revealed that the expressions of miR-155-5p and miR-7023-3p were significantly increased in MC3T3-E1 cells cultured on titanium-coating glass dishes, compared to non-coating, gold-, and stainless steel-coating glass dishes. Interestingly, miR-155-5p was upregulated during osteogenic differentiation of MC3T3-E1 cells. Furthermore, overexpression of miR-155-5p enhanced the expression of Runx2 and Col1a1. In this study, miR-155-5p may be involved in the acquisition of osseointegration on titanium implant via upregulating osteogenic differentiation-related genes.