Lnc‐NTF3‐5 promotes osteogenic differentiation of maxillary sinus membrane stem cells via sponging miR‐93‐3p

BACKGROUND: The function and the mechanism of long non‐coding RNAs (lncRNAs) on the osteogenic differentiation of maxillary sinus membrane stem cells (MSMSCs) remain largely unknown. MATERIALS AND METHODS: The expression of lnc‐NTF3‐5 and Runt‐related transcription factor 2 (RUNX2), Osterix (OSX), and Alkaline Phosphatase (ALP) was examined by quantitative real‐time PCR (qRT‐PCR) in MSMSCs during the process osteogenic differentiation. Then the function of lnc‐NTF3‐5 was evaluated by loss‐ and gain‐of‐function techniques, as well as qRT‐PCR, western blot, and Alizarin Red staining. In addition, the microRNAs (miRNAs) sponge potential of lnc‐NTF3‐5 was assessed through RNA immunoprecipitation, dual luciferase reporter assay, and in vivo ectopic bone formation. RESULTS: Lnc‐NTF3‐5, RUNX2, OSX, and ALP increased alone with the differentiation. Inhibition of lnc‐NTF3‐5 decreased the expression of RUNX2, OSX, and ALP both at mRNA and protein levels. Alizarin red staining showed similar trend. In contrast, overexpression of lnc‐NTF3‐5 presented totally opposite effects. Besides, overexpression of lnc‐NTF3‐5 could decrease the expression of microRNA‐93‐3p (miR‐93‐3p). Enhance miR‐93‐3p could also inhibit the expression level of lnc‐NTF3‐5. RNA immunoprecipitation demonstrated that lnc‐NTF3‐5 is directly bound to miR‐93‐3p and dual luciferase reporter assay proved that miR‐93‐3p targets 3′ UTR of RUNX2 to regulate its expression. Ultimately, in vivo bone formation study showed that lnc‐NTF3‐5 and miR‐93‐3p inhibitor co‐transfection group displayed the strongest bone formation. CONCLUSIONS: The novel pathway lnc‐NTF3‐5/miR‐93‐3p/RUNX2 could regulate osteogenic differentiation of MSMSCs and might serve as a therapeutic target for bone regeneration in the posterior maxilla.