Extracellular vesicles from bone marrow mesenchymal stem cells alleviate osteoporosis in mice through USP7-mediated YAP1 protein stability and the Wnt/β-catenin pathway.

Mesenchymal stem cells (MSCs) and their derived extracellular vesicles (EVs) have emerged as promising tools for promoting bone regeneration. This study investigates the functions of EVs derived from bone marrow-derived MSCs (BMSCs) in osteoporosis (OP) and the molecular mechanism. EVs were isolated from primary BMSCs in mice. A mouse model with OP was induced by ovariectomy. Treatment with EVs restored bone mass and strength, attenuated trabecular bone loss and cartilage damage, and increased osteogenesis while suppressing osteoclastogenesis in ovariectomized mice. In vitro, the EVs treatment improved the osteogenic differentiation of MC-3T3 while inhibiting osteoclastic differentiation of RAW264.7 cells. Microarray analysis revealed a significant upregulation of ubiquitin specific peptidase 7 (USP7) expression in mouse bone tissues following EV treatment. USP7 was found to interact with Yes1 associated transcriptional regulator (YAP1) and stabilize YAP1 protein through deubiquitination modification. YAP1-related genes were enriched in the Wnt/β-catenin signaling, and overexpression of YAP1 promoted the nuclear translocation of β-catenin. Functional experiments underscored the critical role of maintaining USP7, YAP1, and β-catenin levels in the pro-osteogenic and anti-osteoclastogenic properties of the BMSC-EVs. In conclusion, this study demonstrates that USP7, delivered by BMSC-derived EVs, stabilizes YAP1 protein, thereby ameliorating bone formation in OP through the Wnt/β-catenin activation.

Wang X ，Zou C ，Hou C ，Bian Z ，Jiang W ，Li M ，Zhu L ... -  《-》

Extracellular vesicles from GPNMB-modified bone marrow mesenchymal stem cells attenuate bone loss in an ovariectomized rat model.

The efficacy of anti-osteoporotic treatments is still limited. Our study aimed to investigate the effect of extracellular vesicles (EVs) derived from bone marrow-derived MSCs (BMSCs) overexpressing glycoprotein non-melanoma clone B (GPNMB) on osteoporosis (OP). Lentiviral vector for GPNMB overexpression or its negative control was generated and transfected into BMSCs. EVs enriched with GPNMB (GPNMB-EVs) were extracted from GPNMB-modified BMSC-conditioned medium and then identified. Cellular uptake and proliferation were analyzed using the Dil-labeled assay and CCK-8 assay, respectively. Cytochemical staining, western blot, and RT-qPCR analysis were performed to assess the effect of GPNMB-EVs on osteogenic differentiation of BMSCs in vitro. Dickkopf-1 (DKK1) as the inhibitor was applied to explore the Wnt/β-catenin signaling pathway involved in the GPNMB-EV-induced osteogenic differentiation. In vivo experiments were conducted using an ovariectomized (OVX) rat model of postmenopausal osteoporosis, and then assessed the effect of GPNMB-EVs by micro-CT, and histological and immunohistochemical assays. GPNMB-EVs were taken up by BMSCs, and they noticeably promoted the proliferation of BMSCs. Additionally, GPNMB-EVs activated the Wnt/β-catenin signaling to stimulate osteogenesis in BMSCs. In vivo examination showed that GPNMB-EVs remarkably improved trabecular bone regeneration and alleviated the osteoporotic phenotype in the OVX-induced rat model of OP. EVs derived from GPNMB-modified BMSCs significantly stimulated the proliferation and osteogenic differentiation of BMSCs via the activation of Wnt/β-catenin signaling and attenuated the bone loss in the OVX-induced rat model of OP. Our findings suggest the promising potential of GPNMB-EVs as cell-free therapy for the treatment of OP.

Huang B ，Su Y ，Shen E ，Song M ，Liu D ，Qi H ... -  《-》

Morusin induces osteogenic differentiation of bone marrow mesenchymal stem cells by canonical Wnt/β-catenin pathway and prevents bone loss in an ovariectomized rat model.

Chen M ，Han H ，Zhou S ，Wen Y ，Chen L ... -  《Stem Cell Research & Therapy》

Extracellular vesicles derived from bone marrow mesenchymal stem cells loaded on magnetic nanoparticles delay the progression of diabetic osteoporosis via delivery of miR-150-5p.

Extracellular vesicles derived from bone marrow mesenchymal stem cells (BMSC-EVs) are emerged as carriers of therapeutic targets against bone disorders, yet its isolation and purification are limited with recent techniques. Magnetic nanoparticles (MNPs) can load EVs with a unique targeted drug delivery system. We constructed gold-coated magnetic nanoparticles (GMNPs) by decorating the surface of the Fe3O4@SiO2 core and a silica shell with poly(ethylene glycol) (PEG)-aldehyde (CHO) and examined the role of BMSC-EVs loaded on GMNPs in diabetic osteoporosis (DO). The osteoporosis-related differentially expressed miR-150-5p was singled out by microarray analysis. DO models were then established in Sprague-Dawley rats by streptozotocin injection, where poor expression of miR-150-5p was validated in the bone tissues. Next, GMNPE was prepared by combining GMNPs with anti-CD63, after which osteoblasts were co-cultured with the GMNPE-BMSC-EVs. The re-expression of miR-150-5p facilitated osteogenesis in osteoblasts. GMNPE could promote the enrichment of EVs in the bone tissues of DO rats. BMSC-EVs delivered miR-150-5p to osteoblasts, where miR-150-5p targeted MMP14 and consequently activated Wnt/β-catenin pathway. This effect contributed to the enhancement of osteoblast proliferation and maturation. Furthermore, GMNPE enhanced the EV-based delivery of miR-150-5p to regulate the MMP14/Wnt/β-catenin axis, resulting in promotion of osteogenesis. Overall, our findings suggest the potential of GMNP-BMSC-EVs to strengthen osteoblast proliferation and maturation in DO, showing promise as an appealing drug delivery strategy against DO. 1. GMNPs-BMSCs-EVs-miR-150-5p promotes the osteogenesis of DO rats. 2. miR-150-5p induces osteoblast proliferation and maturation by targeting MMP14. 3. Inhibition of MMP14 activates Wnt/β-catenin and increases osteogenesis. 4. miR-150-5p activates the Wnt/β-catenin pathway by downregulating MMP14.

Xu C ，Wang Z ，Liu Y ，Wei B ，Liu X ，Duan K ，Zhou P ，Xie Z ，Wu M ，Guan J ... -  《-》

Circular RNA YAP1 attenuates osteoporosis through up-regulation of YAP1 and activation of Wnt/β-catenin pathway.

Osteoporosis is a systemic bone disease resulting from decreased bone mass and bone microstructure degeneration. Yes-associated protein 1 (YAP1) belongs to YAP family and plays a significant part in controlling bone quality. Present study aimed to study the function and up-stream mechanism of YAP1 in the differentiation of BMSCs (bone marrow stromal cells) and MC3T3-E1. ALP staining, alizarin red staining and western blot analysis of osteogenic biomarkers determined osteogenic differentiation in BMSCs and MC3T3-E1. Mechanistic assays including luciferase reporter assay, RIP assay and RNA pull down assay disclosed the interplays between RNAs. YAP1 promoted osteogenic differentiation of BMSCs and MC3T3-E1. Circ_0024097 originated from YAP1 sponged miR-376b-3p to elevate YAP1 expression in BMSCs and MC3T3-E1. Further, YAP1 mediated circ_0024097- promoted effects on osteogenic differentiation. Moreover, circ_0024097 activated Wnt/β-catenin pathway to facilitate osteogenic differentiation. It was firstly uncovered in present study that circ_0024097 attenuated osteoporosis through promoting osteogenic differentiation via miR-376b-3p/YAP1 axis and Wnt/β-catenin pathway.

Huang Y ，Xiao D ，Huang S ，Zhuang J ，Zheng X ，Chang Y ，Yin D ... -  《-》