Abstract
This study was carried out to explore the roles of circular RNAs (circRNAs) in nucleus pulposus (NP) tissues in intervertebral disc degeneration (IDD). Differentially expressed circRNAs in IDD and normal NP tissues were identified based on the results of microarray analysis. Bioinformatics techniques were employed to predict the direct interactions of selected circRNAs, microRNAs (miR), and mRNAs. CircRNA_104670 was selected as the target circRNA due to its large multiplier expression in IDD tissues. After luciferase reporter and EGFP/RFP reporter assays, we confirmed that circRNA_104670 directly bound to miR-17-3p, while MMP-2 was the direct target of miR-17-3p. The receiver-operating characteristic (ROC) curve showed that circRNA_104670 and miR-17-3p had good diagnostic significance for IDD (AUC circRNA_104670 = 0.96; AUC miRNA-17-3p = 0.91). A significant correlation was detected between the Pfirrmann grade and expression of circRNA_104670 (r = 0.63; p = 0.00) and miR-17-3p (r = −0.62; p = 0.00). Flow-cytometric analysis and the MTT assay showed that interfering with circRNA_104670 using small interfering RNA (siRNA) inhibited NP cell apoptosis (p < 0.01), and this inhibition was reduced by interfering with miR-17-3p. Interfering with circRNA_104670 suppressed MMP-2 expression and increased extracellular matrix (ECM) formation, which were also reduced by interfering with miR-17-3p. Finally, an MRI evaluation showed that circRNA_104670 inhibition mice had a lower IDD grade compared with control mice (p < 0.01), whereas circRNA_104670 and miRNA-17-3p inhibition mice had a higher IDD grade compared with circRNA_104670 inhibition mice (p < 0.05). CircRNA_104670 is highly expressed in the NP tissues of IDD and acts as a ceRNA during NP degradation.
Highlights
Increasing attention has focused on musculoskeletal disorders of the spine, which are associated with low back pain, morbidity, and mental disease
A total of 792 circRNAs were differentially expressed in nucleus pulposus (NP) specimens between intervertebral disc degeneration (IDD) and normal subjects based on the results of the microarray analysis; 428 were upregulated and 364 were downregulated (Fig. 1a, c, d)
To determine the proposed ceRNA mechanism, a network of circRNA-miRNA-miRNAs and target gene (mRNA) was constructed using cytoscape, and their interactions were described based on our circRN- miRNA-mRNA microarray data
Summary
Increasing attention has focused on musculoskeletal disorders of the spine, which are associated with low back pain, morbidity, and mental disease. Several published studies have confirmed that intervertebral disc degeneration (IDD) is mainly responsible for musculoskeletal disorders of the spine[1,2,3]. Basal research has shown that the progression of IDD can be delayed or prevented by treating nucleus pulposus (NP) tissue at the molecular level since IDD has been shown to be involved in a variety of cellular events, from matrix synthesis to cytokine expression[4,5,6,7,8]. It is important to clarify the regulation of extracellular matrix (ECM) catabolism during IDD as this process is always accompanied by the accumulation of ECM-degrading molecules and inflammatory mediators[9]. Increasing attention has been paid to circRNAs, as Official journal of the Korean Society for Biochemistry and Molecular Biology
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
