miR-20a-5p contributes to osteogenic differentiation of human dental pulp stem cells by regulating BAMBI and activating the phosphorylation of Smad5 and p38

• Published in: Stem cell research & therapy 2021-07, Vol.12 (1), p.421-421, Article 421
• Main Authors: Cen, Xiao, Pan, Xuefeng, Zhang, Bo, Huang, Wei, Pei, Fang, Luo, Tao, Huang, Xinqi, Liu, Jun, Zhao, Zhihe
• Format: Article
• Language: English
• Subjects: Activin; BAMBI; Binding sites; Bone growth; Bone remodeling; Cell Differentiation; Cells, Cultured; Computed tomography; Dental pulp; Dental Pulp - metabolism; Gene expression; Human dental pulp stem cells; Humans; Membrane Proteins; Membranes; MicroRNAs; MicroRNAs - genetics; MicroRNAs - metabolism; miR-20a-5p; Osteogenesis; Osteogenesis - genetics; Phosphatase; Phosphorylation; Polymerase chain reaction; Protein binding; Proteins; Reagents; Regeneration; Reverse transcription; Smad5 protein; Smad5 Protein - genetics; Stem cells; Stem Cells - metabolism
• ISSN: 1757-6512; 1757-6512
• DOI: 10.1186/s13287-021-02501-8

Human dental pulp stem cells (hDPSCs) are the preferable choice of seed cells for craniomaxillofacial bone tissue regeneration. As a member of the miR-17-92 cluster, miR-20a-5p functions as an important regulator during bone remodeling. This study aimed to investigate the roles and mechanisms of miR-20a-5p during osteogenesis of hDPSCs. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was conducted to determine the expression of miR-20a-5p during osteogenesis of hDPSCs. We interfered with the expression of miR-20a-5p in hDPSCs to clarify the function of miR-20a-5p on osteogenesis both in vitro and vivo. Direct bind sites between miR-20a-5p and BAMBI were confirmed by dual-luciferase reporter assay, and the underlying mechanisms were investigated with cell co-transfections. The expression of miR-20a-5p was showed to be upregulated during osteogenesis of hDPSCs. Inhibition of miR-20a-5p could weaken the intensity of ALP/ARS staining and downregulate the expression of mRNAs and proteins of osteogenic markers, while overexpression of miR-20a-5p could enhance the intensity of ALP/ARS staining and the expression of osteogenic markers. Both micro-CT reconstruction images and histological results showed that miR-20a-5p could promote the regeneration of calvarial defects. miR-20a-5p directly targeted bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI), and the latter one was an inhibitor of hDPSC osteogenesis. Silencing BAMBI partially reversed the suppression effect of miR-20a-5p knockdown on osteogenesis. Phosphorylation of Smad5 and p38 was decreased when miR-20a-5p was silenced, whereas p-Smad5 and p-p38 were upregulated when miR-20a-5p was overexpressed or BAMBI was silenced. It is demonstrated that miR-20a-5p functioned as a regulator of BAMBI to activate the phosphorylation of Smad5 and p38 during osteogenic differentiation of hDPSCs.