miR-29a promotes osteoblast proliferation by downregulating DKK-1 expression and activating Wnt/β-catenin signaling pathway

MicroRNA (miRNA) is a kind of non-coding small RNA with a negative regulating function. Some miRNAs play a role in regulating the differentiation and function of osteoblasts, chondrocytes and osteoclasts.In this study, we analyzed the role of miR-29a and dickkopf-1 (DKK-1) in osteoblast differentiation.Specimens were collected from the surgical resection of pathological ankylosing spondylitis (AS) tissue and some normal tissues. The expression of miR-29a, DKK-1 and β-catenin in normal and AS tissues were detected with real-time polymerase chain reaction (RT-PCR) and western blotting. Cell proliferation was detected with a Cell Counting Kit-8, cell migration and invasion were determined using a Transwell system and cell apoptosis was analyzed with flow cytometry. The luciferase reporter gene plasmid pGL3-DKK-1 and a point-mutation of the luciferase reporter gene plasmid mut-pGL3-DKK-1 were constructed.It was found that miR-29a could promote the proliferation of hFOB1.19 cells, while DKK-1 inhibited their proliferation. Also, miR-29a was able to inhibit the apoptosis of hFOB1.19 cells, while DKK-1 was able to promote the apoptosis of hFOB1.19 cells. When it comes to the invasion and migration of hFOB1.19 cells, miR-29a was found to promote it, while DKK-1 did not.These findings will lead to a better understanding of the proliferation and differentiation of osteoblasts and will provide new insights for the treatment of this disease.