scholarly journals Knockout of miR-17-92 Cluster Protect Against Intervertebral Disc Degeneration by Inhibiting Apoptosis of Nucleus Pulposus Cells in Mice via the Activation of PI3K/Akt Pathway

Author(s):  
Yingjun Guo ◽  
Yang Meng ◽  
Hao Liu ◽  
Xiaofei Wang ◽  
Ying Hong ◽  
...  

Abstract Background: microRNA(miR)-17-92 cluster is involved in a variety of physiological and pathological processes, and the purpose of this study is to preliminarily explore the role of miR-17-92 cluster in disc degeneration and the corresponding mechanisms.Methods: Hematoxylin and Eosin (HE) and Safranin O Staining were used to evaluate the degeneration of intervertebral disc. qRT-PCR was applied to evaluate the mRNA level of miR-17-92 cluster and functional genes of nucleus pulposus (NP) tissues, whose protein level was evaluated with Western-blot. Terminal-Deoxynucleoitidyl Transferase Mediated Nick End Labeling (TUNEL) was used to evaluate the apoptotic level of nucleus pulposus cell (NPC).Results: The expression levels of members of the miR-17-92 cluster were significantly increased in the NP tissues from patients with intervertebral disc degeneration (IVDD). Furthermore, in the 3-months and 24-months miR-17-92-ccKO mice, the degree of IVDD was significantly lower than that of the control group. At the same time, we also detected the expression levels of related functional genes in the NP tissues of mice in two groups. The results showed that the mRNA and protein levels of Bax and Caspase-3 in the knockout group were significantly lower than those in the control group, and the mRNA and protein levels of Bcl-2 were significantly higher. The TUNEL results showed that the apoptosis level of NPCs in the 3-month knockout mice was significantly lower than that in the control group. Finally, the assessment of pathway-related protein levels showed that p-Ser473-Akt expression ratio in the nucleus pulposus of mice in the knockout group were significantly increased, suggesting that the PI3K/Akt pathway was activated after miR-17-92 cluster knockout.Conclusion: To sum up, miR-17-92 cluster does play an important regulating role in IVDD, and the results showed that miR-17-92 cluster could inhibiting NPCs apoptosis by activating PI3K/Akt pathway, eventually producing protective effect against IVDD.

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Xin Wang ◽  
Jianshi Tan ◽  
Junhao Sun ◽  
Pengzhong Fang ◽  
Jinlei Chen ◽  
...  

Background. Intervertebral disc degeneration is related to tissue fibrosis. ADAMTS can degrade the important components of the ECM during the process of intervertebral disc degeneration, ultimately resulting in the loss of intervertebral disc function. sIL-13Rα2-Fc can inhibit fibrosis and slow down the degeneration process, but the mechanism involved remains unclear. Objective. To determine the mechanism by which sIL-13Rα2-Fc inhibits ECM degradation and reduces intervertebral disc tissue fibrosis using a transcriptomics analysis. Methods. A rat model of caudal intervertebral disc degeneration was established, and Sirius red staining was used to observe the pathological changes in the caudal intervertebral disc. Transcriptome sequencing was employed to assess the gene expression profiles of the intervertebral disc tissues in the model group and the sIL-13Rα2-Fc-treated group. Differentially expressed genes were identified and analyzed using GO annotation and KEGG pathway analyses. Real-time fluorescence quantitative PCR was used to verify the expression levels of candidate genes. The levels of GAG and HA were quantitatively assessed by ELISA, and the levels of collagen I and collagen II were analyzed by western blotting. Results. Sirius red staining showed that in the model group, the annulus fibrosus was disordered, the number of breaks increased, and the type I collagen protein levels increased, whereas in the sIL-13Rα2-Fc group, the annulus fibrosus was ordered, the number of breaks decreased, and the type II collagen protein levels increased. In comparison with the model group, we identified 58 differentially expressed genes in the sIL-13Rα2-Fc group, and these were involved in 35 signaling pathways. Compared with those in the model group, the mRNA expression levels of Rnux1, Sod2, and Tnfaip6 in the IL-13Rα2-Fc group were upregulated, and the mRNA expression levels of Aldh3a1, Galnt3, Fgf1, Celsr1, and Adamts8 were downregulated; these results were verified by real-time fluorescence quantitative PCR. TIMP-1 (an ADAMTS inhibitor) and TIMP-1 combined with the sIL-13Rα2-Fc intervention increased the levels of GAG and HA, inhibited the expression of type I collagen, and promoted the expression of type II collagen. Conclusion. Adamts8 may participate in the degradation of ECM components such as GAG and HA and lead to an imbalance in the ECM of the intervertebral disc, resulting in intervertebral disc degeneration. sIL-13Rα2-Fc promoted anabolism of the ECM and increased the levels of ECM components by inhibiting the expression of Adamts8, thus maintaining the dynamic equilibrium of the ECM and ultimately delaying intervertebral disc degeneration.


Spine ◽  
2002 ◽  
Vol 27 (20) ◽  
pp. 2212-2219 ◽  
Author(s):  
Gabriella Cs-Szabo ◽  
Deborah Ragasa-San Juan ◽  
Vani Turumella ◽  
Koichi Masuda ◽  
Eugene J-M.A. Thonar ◽  
...  

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Longxi Wu ◽  
Jieliang Shen ◽  
Xiaojun Zhang ◽  
Zhenming Hu

The intervertebral disc degeneration (IDD) is considered to be an initiator of a series of spinal diseases, among which changes in the nucleus pulposus (NP) are the most significant. NP cells reside in a microenvironment with a lack of blood vessels, hypoxia, and low glucose within the intervertebral disc. Due to the strong activity of HIF-1α, glycolysis is the main pathway for energy metabolism in NP cells. Our previous study found that higher SIRT1 expression is beneficial to delay the degeneration of NP cells. In order to find the downstream genes by which SIRT1 acts on NP cells, we used iTRAQ sequencing to detect the differences between degenerated NP cells overexpressing SIRT1 and a control group (human NP cells were derived from surgery) and found that the expression of LDHA changed in the same direction with SIRT1. This suggests that SIRT1 may delay the degeneration of NP cells by regulating glycolysis. We then used a Seahorse XFe24 analyzer to measure the bioenergetic parameters of NP cells and obtained three findings: (a) glycolysis is the main energy metabolism pathway in NP cells, (b) there is a large difference in ATP production between senescent cells and young cells, and (c) SIRT1 can regulate the production of ATP from glycolysis by regulating LDHA. We also found that SIRT1 in NP cells has a positive regulatory effect on c-Myc which is an upstream gene of LDHA. Through observing IDD-related indicators such as apoptosis, proliferation, senescence, and extracellular matrix, we found that SIRT1 can delay degeneration, and interference with c-Myc and LDHA, respectively, weakens the protective effect of SIRT1. Interfering with LDHA alone can also inhibit glycolysis and accelerate degeneration. Overall, we found that the inhibition of glycolysis in Np cells significantly affects their normal physiological functions and determined that LDHA is a potential therapeutic target for the treatment of IDD.


2019 ◽  
Author(s):  
Chen Xu ◽  
Shengchang Luo ◽  
Leixin Wei ◽  
Huiqiao Wu ◽  
Wei Gu ◽  
...  

Abstract Background: Intervertebral disc degeneration is a major cause of symptoms like low back pain and neck pain. Many groups have tried to reveal the regulatory network using either transcriptome or proteome profiling technologies, however, the relationship between these differentially expressed proteins and mRNAs are not elucidated. Since post-transcriptional regulation and other mechanisms may affect the translation of mRNA to protein, a combined transcriptome and proteome study may give more precise data on unveiling important regulatory network and key genes of Intervertebral disc degeneration. Results: In the present study, we used the label-free quantification proteomic approach and identify 656 proteins expressed in either degenerated or normal nucleus pulposus, of which 503 proteins are differentially expressed. Taking advantage of the existing nucleus pulposus transcriptome data, we combine and reanalyze the data and find 105 differentially expressed mRNA between degenerated and normal nucleus pulposus. By comparing these data, only 9 genes show significant changes in both protein and mRNA data, while 6 genes (TNFAIP6, CHI3L1, KRT19, DPT, COL6A2 and COL11A2) show concordant changes in both protein and mRNA level. Further functional analyses show different functions of the altered mRNAs and proteins in degeneration, indicating great difference between protein network and mRNA network. Using the gene co-expression network method, we uncover novel regulatory network and potential genes that may play vital roles in intervertebral disc degeneration by combining protein and mRNA data. Conclusions: This is the first study to identify novel regulatory network of intervertebral disc degeneration using combined analysis of both transcriptome and proteome, which may give new insight into the molecular mechanism of intervertebral disc degeneration.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Xue-Lin Lin ◽  
Zhao-Yun Zheng ◽  
Qing-Shan Zhang ◽  
Zhen Zhang ◽  
You-Zhi An

Abstract Objective To investigate the expression of miR-195 and its target gene Bcl-2 in intervertebral disc degeneration (IVDD) and its effect on nucleus pulposus (NP) cell apoptosis. Methods The expressions of miR-195 and Bcl-2 in NP tissues of IVDD patients were quantified by qRT-PCR and western blotting, respectively. NP cells were divided into blank group, TNF-α group, TNF-α + miR-NC group, TNF-α + siBcl-2 group, and TNF-α + miR-195 inhibitors + siBcl-2 group. Cell proliferation was detected by MTT assay, cell apoptosis evaluated by flow cytometry, and mitochondrial membrane potential (MMP) tested by JC-1 staining. Moreover, the function of miR-195 on IVDD in vivo was investigated using a puncture-induced IVDD rat model. Results IVDD patients had significantly increased miR-195 expression and decreased Bcl-2 protein expression in NP tissues. The expression of miR-195 was negatively correlated with the expression of Bcl-2 in IVDD patients. Dual-luciferase reporter gene assay indicated that Bcl-2 was a target gene of miR-195. In comparison with blank group, TNF-α group showed decreased cell proliferation and MMP, increased cell apoptosis, upregulated expression of miR-195, Bax, and cleaved caspase 3, and downregulated Bcl-2 protein, while these changes were attenuated by miR-195 inhibitors. Additionally, siBcl-2 can reverse the protective effect of miR-195 inhibitors on TNF-α-induced NP cells. Besides, inhibition of miR-195 alleviated IVDD degeneration and NP cell apoptosis in the rat model. Conclusion MiR-195 was significantly upregulated in NP tissues of IVDD patients, and inhibition of miR-195 could protect human NP cells from TNF-α-induced apoptosis via upregulation of Bcl-2.


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