The long noncoding RNA HOTAIR serves as a microRNA-34a-5p sponge to reduce nucleus pulposus cell apoptosis via a NOTCH1-mediated mechanism.

Intervertebral disc degeneration (IDD) is a major cause of lower back pain, but the specific molecular mechanisms governing its development are poorly characterized. This study sought to assess to what extent HOTAIR, a long non-coding (Lnc) RNA is expressed in IDD and regulates the apoptotic death of nucleus pulposus (NP) cells. We therefore used real-time qPCR to measure HOTAIR and microRNA(miR)-34a-5p in degenerative NP cells, and then validated their functional relevance via overexpressing them in these NP cells. We further verified the targets of these RNA constructs in 293 T cells through the use of a dual luciferase reporter assay. We further measured NP cell apoptosis via flow cytometry and Notch1 expression via western blotting. Our results indicated that IDD was linked with decreased HOTAIR expression relative to regular NP cells, and overexpressing this lncRNA was linked to reduced apoptotic NP cell death, whereas overexpressing miR-34a-5p had the opposite effect. We found that HOTAIR served as a miR-34a-5p sponge, sequestering this miRNA and thereby down regulating genes linked to apoptosis through the Notch signaling pathway. Even in naturally degenerated NP cells, HOTAIR delayed the onset of apoptosis. Together these results reveal that a HOTAIR/miR-34a-5p/Notch1 signaling pathway may regulate the development of IDD, potentially making HOTAIR a viable target for treatment of this disease.

Shao T ，Hu Y ，Tang W ，Shen H ，Yu Z ，Gu J ... -  《-》

LncRNA HOTAIR suppresses TNF-α induced apoptosis of nucleus pulposus cells by regulating miR-34a/Bcl-2 axis.

The aim of this study was to investigate the regulation mechanism of HOTAIR on nucleus pulposus cell (NPC) apoptosis induced by inflammatory cytokines. QRT-PCR was performed to analyze the expression of HOTAIR and miR-34a. Safranin O staining and immunohistochemical staining were measured to identify NPCs. ELISA assay was used to detect TNF-α level. Apoptosis was detected with TUNEL assay. Western blotting was measured to analyze the expression of caspase-3, Bax and Bcl-2. TargetScan was used to predict potential targets of miR-34a. HOTAIR was significantly low-expressed in degenerative nucleus pulposus (NP) tissues and cells of IDD patients, overexpressing HOTAIR obviously inhibited TNF-α level, NPCs apoptosis and the expression of caspase-3 and Bax, while promoted the expression of Bcl-2. MiR-34a was obviously expressed in degenerative NP tissues and cells of IDD patients. HOTAIR reduced miR-34a induced apoptosis. Apoptotic inhibition gene Bcl-2 is the target gene of miR-34a, and showed a negative relationship with miR-34a. Our data suggest that lncRNA HOTAIR suppresses TNF-α induced NPCs apoptosis by regulating miR-34a/Bcl-2 axis in IDD patients.

Yu Y ，Zhang X ，Li Z ，Kong L ，Huang Y ... -  《-》

CircRNA-CIDN mitigated compression loading-induced damage in human nucleus pulposus cells via miR-34a-5p/SIRT1 axis.

Intervertebral disc degeneration (IDD) is a major contributor to lower back pain, however, the molecular and pathogenetic mechanisms underlying IDD are poorly understood. As a high-risk factor for IDD, compression stress was reported to induce apoptosis of nucleus pulposus (NP) cells and extracellular matrix (ECM) degradation during IDD progression. Circular RNA (circRNA) is a class of endogenous non-coding RNA (ncRNA) and has been reported to function in several diseases. However, whether and how circRNA regulates compression-induced damage of NP cells remains vague. Here, we aimed to investigate the key role of circRNA in compression loading-induced IDD. We analysed the circRNA expression of three samples from compression-treated NP cells and three control samples using circRNA microarray assays and further investigated the circRNA involved in compression-induced damage of NP cells (circRNA-CIDN). We investigated the effects of circRNA-CIDN on compression-induced cell apoptosis and NP ECM degradation in vitro and ex vivo. We observed that circRNA-CIDN bound to miRNAs as a miRNA sponge based on luciferase and RNA immunoprecipitation (RIP) assays. CircRNA-CIDN was significantly downregulated in compression-treated human NP cells, as validated by circRNA microarray and qRT-PCR analysis, and overexpressing circRNA-CIDN inhibited compression-induced apoptosis and NP ECM degradation. Further studies demonstrated that circRNA-CIDN served as a sponge for miR-34a-5p, an important miRNA that enhanced compression-induced damage of NP cells via repressing the silent mating type information regulation 2 homolog 1 (SIRT1). CircRNA-CIDN was also verified to contain IDD development in an ex vivo IDD model. Our results revealed that circRNA-CIDN binding to miR-34a-5p played an important role in mitigating compression loading-induced nucleus pulposus cell damage via targeting SIRT1, providing a potential therapeutic strategy for IDD treatment. National Natural Science Foundation of China (81772391, 81974348), Fundamental Research Funds for the Central Universities (2017KFYXJJ248).

Xiang Q ，Kang L ，Wang J ，Liao Z ，Song Y ，Zhao K ，Wang K ，Yang C ，Zhang Y ... -  《EBioMedicine》

Long non-coding HCG18 promotes intervertebral disc degeneration by sponging miR-146a-5p and regulating TRAF6 expression.

Xi Y ，Jiang T ，Wang W ，Yu J ，Wang Y ，Wu X ，He Y ... -  《Scientific Reports》

Long non-coding RNA HOTAIR modulates intervertebral disc degenerative changes via Wnt/β-catenin pathway.

Zhan S ，Wang K ，Song Y ，Li S ，Yin H ，Luo R ，Liao Z ，Wu X ，Zhang Y ，Yang C ... -  《-》