Department of Orthopaedics, First Affiliated Hospital of Xiamen University, Xiamen 361003, PR China.
Department of Orthopaedics, Zhongshan Hospital of Fudan University, Shanghai 200032, PR China.
Life Sci. 2021 Aug 15;279:119481. doi: 10.1016/j.lfs.2021.119481. Epub 2021 Apr 12.
Muscle and adipose tissue-derived mesenchymal stem cells presented high osteogenic potentials, which modulate osteoblast function through releasing extracellular vesicles (EVs) containing miRNAs. Herein, this study evaluated the function of bone marrow mesenchymal stem cell-derived extracellular vesicles (BMSC-EVs) delivering miR-497-5p in ossification of the posterior longitudinal ligament (OPLL).
The expression level of miR-497-5p was validated in ossified posterior longitudinal ligament (PLL) tissues and BMSC-EVs. The uptake of BMSC-EVs by ligament fibroblasts was observed by immunofluorescence. miR-497-5p was overexpressed or downregulated to assess its role in osteogenic differentiation of ligament fibroblasts. Further, an OPLL rat model was established to substantiate the effect of BMSC-EVs enriched with miR-497-5p on OPLL.
Ossified PLL tissues presented with high miR-497-5p expression. PLL fibroblasts were identified to endocytose BMSC-EVs. BMSC-EVs could upregulate miR-497-5p and shuttle it to ligament fibroblasts to accelerate the osteogenic differentiation. miR-497-5p targeted and inversely regulated RSPO2. Then, RSPO2 overexpression activated Wnt/β-catenin pathway and repressed the osteogenic differentiation of ligament fibroblasts. In vivo experiments further showed that miR-497-5p-containing BMSC-EVs enhanced OPLL through diminishing RSPO2 and inactivating Wnt/β-catenin pathway.
BMSC-EVs could deliver miR-497-5p to ligament fibroblasts and modulate RSPO2-mediated Wnt/β-catenin pathway, thereby accelerating OPLL.
肌肉和脂肪组织来源的间充质干细胞具有较高的成骨潜能，通过释放含有 microRNA（miRNA）的细胞外囊泡（EVs）来调节成骨细胞的功能。本研究评估了骨髓间充质干细胞衍生的细胞外囊泡（BMSC-EVs）递送 miR-497-5p 在骨化性后纵韧带（OPLL）中的作用。
验证骨化后纵韧带（PLL）组织和 BMSC-EVs 中 miR-497-5p 的表达水平。通过免疫荧光观察韧带成纤维细胞对 BMSC-EVs 的摄取。过表达或下调 miR-497-5p 以评估其在韧带成纤维细胞成骨分化中的作用。进一步建立 OPLL 大鼠模型，以证实富含 miR-497-5p 的 BMSC-EVs 对 OPLL 的影响。
骨化 PLL 组织中 miR-497-5p 表达水平较高。鉴定出 PLL 成纤维细胞内吞 BMSC-EVs。BMSC-EVs 可以上调 miR-497-5p 并将其转染到韧带成纤维细胞中，加速成骨分化。miR-497-5p 靶向并反向调节 RSPO2。然后，RSPO2 的过表达激活了 Wnt/β-catenin 通路并抑制了韧带成纤维细胞的成骨分化。体内实验进一步表明，含 miR-497-5p 的 BMSC-EVs 通过减少 RSPO2 和使 Wnt/β-catenin 通路失活来增强 OPLL。
BMSC-EVs 可以将 miR-497-5p 递送至韧带成纤维细胞，并调节 RSPO2 介导的 Wnt/β-catenin 通路，从而加速 OPLL。
