CircGLCE alleviates intervertebral disc degeneration by regulating apoptosis and matrix degradation through the targeting of miR-587/STAP1

Abstract

BackgroundIntervertebral disc degeneration (IDD) can induce profound global socioeconomic burdens. Recent studies have suggested that circular RNAs might have crucial functions in the progression of IDD. The purpose of this study was to identify a specific circular RNA and to investigate its regulatory mechanism in IDD.MethodsCircGLCE was selected after microarray analyses and was further analysed by RT-qPCR and FISH. After silencing CircGLCE, its function was assessed with RT-qPCR, immunofluorescence analysis and flow cytometry. Based on Sanger sequencing, miR-587 was identified as a direct target of CircGLCE, and it was further examined with RNA pulldown assays, RT-qPCR, dual luciferase assays and FISH. After silencing CircGLCE or miR-587, western blotting, immunofluorescence analysis, and flow cytometry were conducted. STAP1 was assessed by RT-qPCR and luciferase assay, and experiments with silenced and overexpressed miR-587 were performed. A rescue experiment was also included. In an IDD rat model, the in vivo effects of overexpressing CircGLCE on IDD were analysed with imaging techniques, TUNEL staining, FISH, western blotting, H&E staining and immunohistochemistry.ResultsCircGLCE was found to stably exist in the cytoplasm of nucleus pulposus (NP) cells. It was downregulated in IDD. Knockdown of CircGLCE promoted apoptosis and induced the expression of matrix-degrading enzymes in NP cells. CircGLCE served as a miR-587 sponge in NP cells. Inhibiting miR-587 counteracted the IDD-enhancing effect caused by silencing CircGLCE. STAP1 served as the miRNA target that mediated the functions of miR-587. Overexpressing CircGLCE alleviated IDD in vivo.ConclusionsCircGLCE attenuates IDD by regulating the apoptosis of NP cells and by regulating ECM degradation through the targeting of miR-587/STAP1. CircGLCE may be a potential therapeutic target for IDD treatments.

Single Impact Injury of Vertebral Endplates Without Structural Disruption, Initiates Disc Degeneration Through Piezo1 Mediated Inflammation and Metabolism Dysfunction

“…This suggests that the glycolysis in the IVD cells might be promoted by impact injury. Interestingly, although previous research suggested that intracellular ATP of NP cells might be mainly produced via mitochondrial respiration instead of glycolysis, 12,25 increased NO production detected in our study suggested that ATP production in IVD cells via mitochondrial respiration might be inhibited by impact injury. However, we did not separate the NP and AF cells when evaluating the data.…”

“…Immunofluorescence staining was performed according to the method previously reported. 25 After stained with DAPI, the cells were examined with a confocal microscope (A1R; Nikon, Japan) and analyzed with ImageJ software (Rawak Software, Germany).…”

Role of PI3K/AKT Signaling Pathway in Nucleus Pulposus Cells

“…NP cells as the main components of the nucleus pulposus are responsible for the production and maintenance of extracellular matrix (ECM) containing collagen fibres and variety of proteoglycans especially aggrecan bearing compressive loads [4]. It is generally believed that IDD is partly caused due to the depletion of NP cells and degradation of ECM [5]. Reactive oxygen species resulting from Mitochondria dysfunction or inflammatory factors such as IL-1β and TNF-α tend to trigger apoptosis and disrupt the dynamic balance between ECM synthesis and degradation in NP cells [6,7].…”

Identification of Differentially Expressed circRNAs, miRNAs, and Genes in Patients Associated with Cartilaginous Endplate Degeneration

“…In recent years, noncoding RNAs (ncRNAs) have drawn growing attention because of the role which they play in a spectrum of chronic degenerative diseases of the spine and joints, encompassing IDD [12][13][14][15][16], ankylosing spondylitis [17], osteoarthritis [18,19], and rheumatoid arthritis [20]. Circular RNAs (circRNAs), microRNAs (miRNAs), and long ncRNAs are the members of the family of ncRNAs.…”

“…MiRNAs bind to their target mRNAs to initiate degradation or repress their translation [21].CircRNAs have been determined to be involved in multiple biological processes to mediate IDD progression, such as cell death and growth, as well as inflammatory response and ECM metabolism [12][13][14][15][16]. Furthermore, circRNAs have also been demonstrated to have the therapeutic effect on IDD model rats [14][15][16]. Mechanistically, circRNAs acts as a competitive endogenous RNA (ceRNA) to sponge miRNAs, thereby positively regulating target mRNAs expression [12].…”