MicroRNA-99a is a novel regulator of KDM6B-mediated osteogenic differentiation of BMSCs

J Cell Mol Med. 2018 Apr;22(4):2162-2176. doi: 10.1111/jcmm.13490. Epub 2018 Jan 29.


Skeletal tissue originates from mesenchymal stem cells (MSCs) with differentiation potential into the osteoblast lineage regulated by essential transcriptional and post-transcriptional mechanisms. Recently, miRNAs and histone modifications have been identified as novel key regulators of osteogenic differentiation of MSCs. Here, we identified miR-99a and its target lysine (K)-specific demethylase 6B (KDM6B) gene as novel modulators of osteogenic differentiation of bone mesenchymal stem cells (BMSCs). Microarray profiling and further validation by quantitative real-time RT-PCR revealed that miR-99a was up-regulated during osteoblastic differentiation of BMSCs, and decreased in differentiated osteoblasts. Transfection of miR-99a mimics inhibited osteoblastic commitment and differentiation of BMSCs, whereas inhibition of miR-99a by inhibitors enhances these processes. KDM6B was determined as one of important targets of miR-99a, which was further confirmed by luciferase assay of 3'-UTR of KDM6B. Moreover, HOX gene level decreased after transfection of miR-99a mimics in BMSCs, which indicated that KDM6B is a bona fide target of miR-99a. Furthermore, in a model of in vivo bone regeneration, osteoblast-specific gain- and loss-of-function experiments performed using cranial bone defects revealed that miR-99a mimics-transfected BMSCs reduced bone formation, and conversely, miR-99a inhibitors-transfected BMSCs increased in vivo bone formation. Tissue-specific inhibition of miR-99a may be a potential novel therapeutic approach for enhancing BMSCs-based bone formation and regeneration.

Keywords: BMSCs; KDM6B; miR-99a; osteogenic differentiation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Bone Marrow / metabolism
  • Bone Marrow / pathology
  • Cell Differentiation / genetics*
  • Cell Line
  • Cells, Cultured
  • Down-Regulation / genetics
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism
  • Jumonji Domain-Containing Histone Demethylases / genetics
  • Jumonji Domain-Containing Histone Demethylases / metabolism*
  • Male
  • Mesenchymal Stem Cells / metabolism*
  • Mice, Inbred C57BL
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Osteogenesis / genetics*
  • Osteoporosis / genetics
  • Osteoporosis / pathology
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Transcription, Genetic
  • Wound Healing


  • Homeodomain Proteins
  • MicroRNAs
  • Mirn99 microRNA, mouse
  • RNA, Messenger
  • Jumonji Domain-Containing Histone Demethylases
  • Kdm6b protein, mouse