Novel lncRNA LncMSTRG.11341.25 Promotes Osteogenic Differentiation of Human Bone Marrow Stem Cells via the miR-939-5p/PAX8 Axis.

Human bone marrow stem cells (hBMSCs) play an important role during the fracture healing phase. Previous clinical studies by our research group found that fracture healing time was obviously delayed in patients who underwent splenectomy, for combined traumatic fractures and splenic rupture, which is most likely related to the dysregulation of immune inflammatory function of the body after splenectomy. A large number of studies have reported that the inflammatory factor interleukin-1β plays an important role in the multi-directional differentiation ability and immune regulation of BMSC, but its specific regulatory mechanism needs to be further studied. Recently, long noncoding RNAs (lncRNAs) have attracted remarkable attention owing to their close relationship with stem cell osteogenesis and potential role in various bone diseases. In this study, we explored the molecular mechanism of a novel lncRNA, LncMSTRG.11341.25 (LncMSTRG25), in terms of its effects on osteogenic differentiation of hBMSCs. Our results reveal significant up-regulation of LncMSTRG25, osteogenic differentiation markers during the osteogenic differentiation of hBMSCs, and decreased expression of miR-939-5p with an increase in differentiation time. LncMSTRG25 knockdown significantly inhibited the osteogenic ability of hBMSCs. When we knocked down PAX8 alone, we found that the osteogenic ability of hBMSCs was also significantly reduced. The interaction between LncMSTRG25 and PAX8 was verified using the RNA immunoprecipitation assay, RNA pull-down assays, silver staining, and the dual-luciferase reporter. The results show that LncMSTRG25 can function as a sponge to adsorb miR-939-5p, inducing the osteogenic differentiation of hBMSCs by activating PAX8. These findings deepen our understanding of the regulatory role of lncRNA-miRNA-mRNA networks in the immune microenvironment of bone marrow, and highlight the important role played by the spleen as an immune organ in fracture healing.