Long Noncoding RNA Metastasis-Associated Lung Adenocarcinoma Transcript 1 Promotes the Osteoblast Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells by Targeting the microRNA-96/Osterix Axis

Objectives: To investigate whether and how the long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) sponges microRNA-96 (miR-96) to achieve the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs). Methods: Protein levels were detected by Western blot. Mineralized bone matrix formation was studied by alizarin red staining. Metastasis-associated lung adenocarcinoma transcript 1, miR-96, and osteogenesis-related Messenger RNA expression was assessed by Quantitative Real-time Polymerase Chain Reaction (qRT-PCR). The interactions between miR-96 and osterix (Osx), MALAT1, and miR-96 were determined by luciferase reporter assay. Results: The expression of MALAT1 was upregulated whereas that of miR-96 was downregulated in osteogenic hBMSCs. In addition, the expression of MALAT1 significantly decreased whereas that of miR-96 increased in the hBMSCs of osteoporosis (OP) patients. qRT-PCR and alizarin red staining assays showed that MALAT1 silencing or miR-96 overexpression inhibits hBMSC osteogenic differentiation and vice versa. overexpression of miR-96 reversed the promotive effect of MALAT1 on the osteogenic differentiation of hBMSCs. Dual luciferase report assay verified that miR-96 is a regulatory target of MALAT1 and that Osx is a gene target of miR-96. Conclusions: Taken together, the results demonstrate that MALAT1 promotes the osteogenic differentiation of hBMSCs by regulating the miR-96/Osx axis. Our study provides novel mechanistic insights into the critical role of lncRNA MALAT1 as a microRNA sponge in OP patients and sheds new light on lncRNA-directed diagnostics and therapeutics in OP.