Arthritis Research & Therapy (Nov 2020)

MicroRNA-15b shuttled by bone marrow mesenchymal stem cell-derived extracellular vesicles binds to WWP1 and promotes osteogenic differentiation

  • Yanhong Li,
  • Jing Wang,
  • Yanchao Ma,
  • Wenjia Du,
  • Haijun Feng,
  • Kai Feng,
  • Guangjie Li,
  • Shuanke Wang

DOI
https://doi.org/10.1186/s13075-020-02316-7
Journal volume & issue
Vol. 22, no. 1
pp. 1 – 15

Abstract

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Abstract Background Osteogenic differentiation is an essential process for bone regeneration involving bone marrow mesenchymal stem cells (BMSCs). BMSC-secreted extracellular vesicles (EVs) enriched with microRNAs (miRs) have vital roles to play in mediating osteogenic differentiation. Therefore, this study aimed to explore the effect of BMSC-derived EVs loaded with miR-15b on osteogenic differentiation. Methods Human BMSCs (hBMSCs) were cultured and treated with plasmids overexpressing or knocking down KLF2, WWP1, and miR-15b to define the role of derived EVs in osteogenic differentiation in vitro. The expression of osteogenic differentiation-related marker was measured by Western blot analysis. The interaction among miR-15b, WWP1, and ubiquitination of KLF2 was investigated by dual-luciferase reporter, immunoprecipitation, and GST pull-down assays. Moreover, EVs from hBMSCs transfected with miR-15b inhibitor (EV-miR-15b inhibitor) were injected into ovariectomized rats to verify the effect of miR-15b on bone loss in vivo. Results WWP1 was downregulated, and KLF2 was upregulated during osteogenic differentiation. After co-culture with EVs, miR-15b expression was elevated and WWP1 expression was reduced in hBMSCs. Upregulation of miR-15b or KLF2 or downregulation of WWP1 or NF-κB increased ALP activity and cell mineralization, as well as osteogenic differentiation-related marker expression in hBMSCs. Mechanistically, miR-15b targeted and inhibited WWP1, thus attenuating KLF2 degradation and inhibiting NF-κB activity. Co-culture of EVs increased the bone volume and trabecular number, but decreased bone loss in ovariectomized rats, which could be reversed after treatment with EV-miR-15b inhibitor. Conclusion Collectively, BMSC-derived EVs loaded with miR-15b promoted osteogenic differentiation by impairing WWP1-mediated KLF2 ubiquitination and inactivating the NF-κB signaling pathway. Graphical abstract

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