LncRNA TUG1 influences osteoblast proliferation and differentiation through the Wnt/β-catenin signaling pathway.

Abstract

Long non-coding ribonucleic acids (lncRNAs) play a vital role in bone development, but the function of lncRNA taurine up-regulated gene 1 (TUG1) in osteoblast proliferation and differentiation is still unknown. The expression of TUG1 and the messenger RNA (mRNA) expressions of the Wnt/β-catenin signaling pathway markers [Runt-related transcription factor 2 (Runx2), Frizzled-2, axis inhibition protein 2 (Axin 2) and β-catenin] at 0 d, 1 d, 7 d and 14 d after in vitro culture of osteoblasts were detected, respectively, by Reverse Transcription-Polymerase Chain Reaction (RT-PCR). The effects of TUG1 on the Wnt/β-catenin signaling pathway markers and osteoblast proliferation and differentiation were studied through the silencing of TUG1 by short hairpin TUG1 (shTUG1). Furthermore, the effects of the Wnt/β-catenin signal on osteoblast proliferation and differentiation was verified by Wnt/β-catenin signal inhibitors. With the continuous differentiation of osteoblasts, the level of TUG1 was significantly increased. The mRNA levels of the Wnt/β-catenin signaling pathway markers (Runx2, Frizzled-2, Axin 2 and β-catenin) also showed the same increasing trend. ShTUG1 notably reduced the activity of alkaline phosphatases (ALPs), the levels of osteocalcin and osteopontin and osteoblast proliferation activity. In addition, the silencing of TUG1 by shTUG1 resulted in significant reductions in the proteins of the Wnt/β-catenin signaling pathway markers (Runx2, Frizzled-2, Axin 2 and β-catenin), and Wnt/β-catenin inhibitors markedly reduced osteoblast proliferation and differentiation activity. LncRNA TUG1 inhibition can suppress the Wnt/β-catenin signaling pathway and reduce osteoblast proliferation and differentiation.