LINC00641 regulates autophagy and intervertebral disc degeneration by acting as a competitive endogenous RNA of miR-153-3p under nutrition deprivation stress

Emerging evidence supports the involvement of autophagy in the pathogenesis of intervertebral disc degeneration (IDD). MicroRNAs (miRNAs) and long noncoding RNAs (lncRNAs) play fundamental roles in various cellular processes, including autophagy. However, it remains largely unknown as to how autophagy is regulated by miRNAs and lncRNAs in IDD. Biological functions of miR-153-3p and long intergenic nonprotein coding RNA 641 (LINC00641) were investigated. Luciferase reporter assays was done to validate miR-153-3p targets. To induce nutritional stress, nucleus pulposus (NP) cells were cultured in the normal nutritional condition and the low nutritional condition. Quantitative reverse-transcription polymerase chain reaction (RT-qPCR) was used to analyze miR-153-3p and LINC00641 in response to nutrient deprivation. Autophagic activity was assessed by transmission electron microscopy, western blot analysis and green fluorescent protein-light chain 3 puncta. Pull-down assay and RNA fluorescent in situ hybridization were performed to validate LINC00641 target and the location. MiR-153-3p is downregulated in NP tissues from IDD patients. Further, LINC00641 can affect collagen II and matrix metalloproteinase-3 expressions. Upregulation of LINC00641 and downregulation of miR-153-3p are detected in NP cells under nutritional stress. LINC00641 can regulate autophagic cell death by targeting miR-153-3p and autophagy-related gene 5 (ATG5). MiR-153-3p inhibits autophagy and IDD by targeting ATG5. More important, LINC00641 targets miR-153-3p, and thus affects ATG5 expression, autophagic cell death and IDD. These findings uncover a novel regulatory pathway that is composed of LINC00641, miR-153-3p, and ATG5 in IDD. This mechanism may stimulate to a more understanding of IDD pathogenesis and provide new sights for the treatment of this disorder.