microRNA-935-modified bone marrow mesenchymal stem cells-derived exosomes enhance osteoblast proliferation and differentiation in osteoporotic rats.

The involvement of several microRNAs (miRNAs) in osteogenic differentiation has been indicated recently. Also, exosomes, derived from different cells, could shuttle specific miRNAs to other cell systems. Nevertheless, the effect and mechanism of microRNA-935 (miR-935)-containing exosomes in osteoblasts remain basically unclear. The current work was set to inspect the relevance of bone marrow mesenchymal stem cells (BMSCs)-derived exosomes (BMSC-exo) carrying miR-935 to osteoporotic rats. The extracted BMSCs and purchased osteoblasts were cultured, followed by exosome isolation and identification. After cell grouping, osteoblasts were co-cultured with BMSCs. CCK-8, alizarin red staining as well as ALP staining were performed to detect osteoblast proliferation and activity. The binding connection between miR-935 and signal transducer and activator of transcription 1 (STAT1) was measured by dual-luciferase reporter gene assays. The expression profiles of miR-935, STAT1 and osteoblast-related proteins were assessed by RT-qPCR and Western blot. A rat model with osteoporosis was induced, and the BMD, BV/TV, Tb.N, Tb.Th and Tb.Sp values in rat bone tissues were observed by Micro-CT. BMSC-exo inhibited STAT1 levels by the delivery of miR-935 into osteoblasts, while STAT1 silencing promoted ALP activity in osteoblasts and mineralized nodules. STAT1 was identified as a target gene of miR-935. Moreover, in vivo experiments showed that in ovariectomized rats, silencing of miR-935 significantly reduced BMD, BV/TV, Tb.N, Tb.Th and increased Tb.Sp. BMSC-exo carry miR-935 to promote osteoblast proliferation and differentiation through targeting STAT1.

Zhang Y ，Cao X ，Li P ，Fan Y ，Zhang L ，Ma X ，Sun R ，Liu Y ，Li W ... -  《-》

LncRNA MALAT1 shuttled by bone marrow-derived mesenchymal stem cells-secreted exosomes alleviates osteoporosis through mediating microRNA-34c/SATB2 axis.

Yang X ，Yang J ，Lei P ，Wen T ... -  《Aging-US》

Bone Marrow Mesenchymal Stem Cells-Derived Exosomal MicroRNA-150-3p Promotes Osteoblast Proliferation and Differentiation in Osteoporosis.

Qiu M ，Zhai S ，Fu Q ，Liu D ... -  《-》

Role of miR-199a-5p in osteoblast differentiation by targeting TET2.

miR-199a-5p was increased during osteoblast differentiation, which may target and regulate TET2, a gene attracted a lot of attention in the osteoblast differentiation in the past few years. However, the role of miR-199a-5p in osteoblast differentiation by targeting TET2 is not established. The correlation between miR-199a-5p and TET2 was verified through dual luciferase reporter assay, and their expressions in human bone marrow stromal cells (hBMSCs) during the osteoblast differentiation were detected. hBMSCs were transfected with TET2 siRNA, miR-199a-5p mimic or/and TET2 CRISPR activation plasmid., and then prepared for the induction of osteoblast differentiation, followed by alkaline phosphatase (ALP) and alizarin red staining, qRT-PCR and Western blotting. In vivo, ovariectomized (OVX) mice were injected with agomir-miR-199a-5p, antagomiR-199a-5p or/and TET2 siRNA to calculate the BMD and BV/TV ratio of mice, as well as to measure the expressions of osteogenesis-related genes in bone tissues. A gradual increase of miR-199a-5p was observed in hBMSCs during the induction of osteoblast differentiation, while TET2 expression was decreased. Besides, miR-199a-5p was reduced in the bone tissue of OVX mice, while TET2 was up-regulated. In addition, overexpression of miR-199a-5p and inhibition of TET2 augmented ALP activity in hBMSCs, with the enhanced calcification and the up-regulated expressions of Runx2, OSX and OCN, which also increased the quality of bone in OVX mice accompanying the enhancement BV/TV ratio, BMD and osteogenesis-related genes. MiR-199a-5p may promote the osteoblast differentiation and prevent OVX-induced osteoporosis by targeting TET2.

Qi XB ，Jia B ，Wang W ，Xu GH ，Guo JC ，Li X ，Liu JN ... -  《-》

Bone marrow mesenchymal stem cell-derived exosomal miR-206 promotes osteoblast proliferation and differentiation in osteoarthritis by reducing Elf3.

MicroRNAs (miRNAs) serve as gene silencers involved in essential cell functions. The role of miR-206 and E74-like factor 3 (Elf3) has been identified in osteoarthritis (OA), while the effect of exosomal miR-206 from bone marrow mesenchymal stem cells (BMSCs) in OA remains largely unknown. Thus, we aim to explore the role of exosomal miR-206 from BMSCs in OA with the involvement of Elf3. BMSCs and BMSC-derived exosomes (BMSC-exos) were obtained and identified. OA mouse models were constructed by anterior cruciate ligament transection and then treated with BMSC-exos or BMSC-exos containing miR-206 mimic/inhibitor. The expression of miR-206, Elf3, inflammatory factors, osteocalcin (OCN) and bone morphogenetic protein 2 (BMP2) in mouse femoral tissues was assessed. The pathological changes in mouse femur tissues were observed. The mouse osteoblasts were identified and treated with untransfected or transfected BMSC-exos, and then, the expression of miR-206, Elf3, OCN and BMP2 was determined. The alkaline phosphatase (ALP) activity, calcium deposition level, OCN secretion, proliferation, apoptosis and cell cycle arrest in osteoblasts were measured. MiR-206 was down-regulated while Elf3 was up-regulated in OA animal and cellular models. Exosomal miR-206 ameliorated inflammation and increased expression of OCN and BMP2 in mouse femoral tissues. Moreover, exosomal miR-206 promoted ALP activity, calcium deposition level, OCN secretion and proliferation and inhibited apoptosis in OA osteoblasts. Overexpressed Elf3 reversed miR-206 up-regulation-induced effects on OA osteoblasts. BMSC-derived exosomal miR-206 promotes proliferation and differentiation of osteoblasts in OA by reducing Elf3. Our research may provide novel targets for OA treatment.

Huang Y ，Zhang X ，Zhan J ，Yan Z ，Chen D ，Xue X ，Pan X ... -  《-》