LncRNA UCA1 affects osteoblast proliferation and differentiation by regulating BMP-2 expression.

OBJECTIVE

The aim of this study was to detect the expression of long non-coding ribonucleic acid (lncRNA) urothelial carcinoma associated 1 (UCA1) in the plasma of patients with osteoporosis (OST), and to investigate its influences on the proliferation and differentiation of osteoblasts and its mechanism.

PATIENTS AND METHODS

Plasma samples were collected from 52 OST patients treated in our hospital and 30 healthy subjects receiving a physical examination, respectively. The expression level of lncRNA UCA1 in OST patients and healthy subjects were detected via Reverse Transcription-Polymerase Chain Reaction (RT-PCR). Furthermore, osteoblast MC3T3-E1 cell lines with a stable knockout of UCA1 in mice were constructed using small-interfering RNA (siRNA). The influence of UCA1 knockout on the proliferation of osteoblasts was detected using cell counting kit-8 (CCK-8) assay. Meanwhile, the proportion of EdU-positive cells in osteoblasts of the control group and UCA1 knockout group was detected using EdU staining. Moreover, the messenger RNA (mRNA) levels of differentiation-related genes, including Runt-related transcription factor 2 (Runx2), Collagen1α1, osteoclast (OC), osteoprotegerin (OPG), osteopontin (OPN) and Osterix (OSX), were detected via RT-PCR. The protein expression level of Runx2 was detected via Western blotting. In addition, osteoblasts were cultured with a bone-derived medium for 14 d. Then, the differentiation status was detected via alizarin red staining and alkaline phosphatase staining. Finally, the expression of bone morphogenetic protein-2 (BMP-2)/(Smad1/5/8) signaling pathway was analyzed using Western blotting.

RESULTS

The expression of plasma lncRNA UCA1 was significantly increased in OST patients (p<0.05). Cell experiments revealed that UCA1 siRNA intervention could significantly promote the proliferation and differentiation of osteoblast MC3T3-E1 cell lines. In addition, Western blotting showed that the pro-apoptotic effect of UCA1 might be mediated by the BMP-2/(Smad1/5/8) signaling pathway in osteoblasts.

CONCLUSIONS

Inhibiting lncRNA UCA1 can promote the proliferation and differentiation of osteoblasts by activating the BMP-2/(Smad1/5/8) signaling pathway in osteoblasts. Therefore, UCA1 is expected to be a new therapeutic target for OST.