Down-regulation of hsa-circ-0107593 promotes osteogenic differentiation of hADSCs via miR-20a-5p/SMAD6 signaling

Objectives: Increasing evidence indicated circRNAs were involved in stem cells osteogenesis differentiation. Herein, we aimed to clarify the role of hsa-circ-0107593 during the osteogenesis process of human adipose-derived stem cells (hADSCs) and the underlying mechanisms.

Methods: The ring structure of hsa-circ-0107593 was confirmed using RNase R treatment and Sanger sequencing. Nucleoplasmic separation and fluorescence in situ hybridization detected hsa-circ-0107593 distribution. Lentivirus and siRNA were used to modulate the expression of hsa-circ-0107593, and the binding relationship between hsa-circ-0107593 and miR-20a-5p was verified by luciferase assay and RNA immunoprecipitation. We detected the osteogenic activity of hADSCs through alkaline phosphatase staining, alizarin red S staining, real-time polymerase chain reaction (RT-PCR), western blot, and cellular immunofluorescence experiment. In vivo, micro-computed tomography was performed to analyze bone formation around skull defect.

Results: RT-PCR results exhibited that hsa-circ-0107593 was downregulated while miR-20a-5p was upregulated during hADSCs osteogenesis. In vivo and in vitro experiments results indicated that knocking down hsa-circ-0107593 promoted the osteogenic differentiation of hADSCs, while overexpression of hsa-circ-0107593 showed an inhibitory effect on hADSCs osteogenic differentiation. In vitro experiment results showed hsa-circ-0107593 acted as a hADSCs osteogenic differentiation negative factor for it inhibited the suppressing effect of miR-20a-5p on SMAD6.

Conclusion: Knocking down hsa-circ-0107593 acts as a positive factor of the osteogenic differentiation of hADSCs via miR-20a-5p/SMAD6 signaling.