Abstract
Increasing evidence has indicated that bone morphogenetic protein 2 (BMP2) coordinates with microRNAs (miRNAs) to form intracellular networks regulating mesenchymal stem cells (MSCs) osteogenesis. This study aimed to identify specific miRNAs in rat adipose-derived mesenchymal stem cells (ADSCs) during BMP2-induced osteogenesis, we selected the most significantly down-regulated miRNA, miR-146a, to systematically investigate its role in regulating osteogenesis and bone regeneration. Overexpressing miR-146a notably repressed ADSC osteogenesis, whereas knocking down miR-146a greatly promoted this process. Drosophila mothers against decapentaplegic protein 4 (SMAD4), an important co-activator in the BMP signaling pathway, was miR-146a’s direct target and miR-146a exerted its repressive effect on SMAD4 through interacting with 3′-untranslated region (3′-UTR) of SMAD4 mRNA. Furthermore, knocking down SMAD4 attenuated the ability of miR-146a inhibitor to promote ADSC osteogenesis. Next, transduced ADSCs were incorporated with poly(sebacoyl diglyceride) (PSeD) porous scaffolds for repairing critical-sized cranial defect, the treatment of miR-146a inhibitor greatly enhanced ADSC-mediated bone regeneration with higher expression levels of SMAD4, Runt-related transcription factor 2 (Runx2) and Osterix in newly formed bone. In summary, our study showed that miR-146a negatively regulates the osteogenesis and bone regeneration from ADSCs both in vitro and in vivo.
Highlights
Cascade through chemotaxis and by stimulating the proliferation and differentiation of the osteoblastic cell lineage[10,11]
These findings suggest that complicate and intricate intracellular regulatory networks are involved in the regulation of osteoblast phenotype commitment and maturation of osteoprogenitors, and a better understanding of the molecular mechanisms underlying the interaction between BMP signaling and other regulatory components or pathways could provide considerable insights into the regulatory networks involved, and aid in developing efficient approaches to treat bone defects
To test the role of signal transducer and activator of transcription 3 (STAT3) in regulating miR-146a, Adipose-derived mesenchymal stem cells (ADSCs) were treated with a specific STAT3 inhibitor (WP1066) and Quantitative real-time PCR (qPCR) results showed that intracellular miR-146a level was decreased after the inactivation of STAT3 when compared to the control (Supplementary Fig. S1D)
Summary
Cascade through chemotaxis and by stimulating the proliferation and differentiation of the osteoblastic cell lineage[10,11]. Accumulating evidence has indicated that positive, negative, or synergistic effects are observed when the BMPs interacts with the MAPK, Wnt, Hedgehog (Hh), Notch, Akt/mTOR and microRNAs signaling pathways, which orchestrate in the regulation of BMP-induced signaling on bone dynamics[16]. Microarray analysis has revealed a series of differentially expressed miRNAs in C2C12 myoblast cell line during the BMP2-induced osteogenic differentiation, and these miRNAs exert negative effects on osteoblast differentiation by regulating the BMP signaling pathway[22,23]. These physiological regulations mediated by miRNAs are important for balancing bone formation and resorption processes. Our data present new insights into the role of miR-146 in ADSC osteogenic differentiation and bone formation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
