Cell type-specific effects of Notch signaling activation on intervertebral discs: Implications for intervertebral disc degeneration

Abstract Background Intervertebral disc degeneration (IVDD)-related disorders are the major causes of low back pain. A previous study suggested that Notch activation serves as a protective mechanism and is a part of the compensatory response that maintains the necessary resident nucleus pulposus (NP) cell proliferation to replace lost or non-functional cells. However, the exact mechanism remains to be determined. In this study, we aimed to investigate the role of JAG2/Notch2 in NP cell proliferation and apoptosis. Methods Recombinant JAG2 or Notch2, Hes1, and Hey2 siRNAs were used to activate or inhibit Notch signaling. Cell proliferation, apoptosis, cell cycle regulatory factors, and pathways associated with Notch-mediated proliferation were examined. In vivo experiments involving an intradiscal injection of Sprague-Dawley rats were performed. Results Recombinant JAG2 induced Notch2 and Hes1/Hey2 expression together with NP cell proliferation. Downregulation of Notch2/Hes1/Hey2 induced G0/G1 phase cell cycle arrest in NP cells. Moreover, Notch2 mediated NP cell proliferation by regulating cyclin D1 and by activating PI3K/Akt and Wnt/β-catenin signaling. Furthermore, Notch signaling inhibited TNF-α-promoted NP cell apoptosis by suppressing the formation of the RIP1-FADD-caspase-8 complex. Finally, we found that intradiscal injection of JAG2 alleviated IVDD and that sh-Notch2 aggravated IVDD in a rat model. These results indicated that JAG2/Notch2 inhibited IVDD by modulating cell proliferation, apoptosis, and extracellular matrix. The JAG2/Notch2 axis regulated NP cell proliferation via PI3K/Akt and Wnt/β-catenin signaling and inhibited TNF-α-induced apoptosis by suppressing the formation of the RIP1-FADD-caspase-8 complex. Conclusions The current and previous results shed light on the therapeutic implications of targeting the JAG2/Notch2 axis to inhibit or reverse IVDD.

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Notch Signaling In B-ALL Reveals PLK1 As A Potential Therapeutic Target In B-ALL: PLK1-Selective Inhibitor Poloxin Modulates Cyclin B and P53 Pathways, Leading To Growth Arrest and Apoptosis

Blood ◽

10.1182/blood.v122.21.2912.2912 ◽

2013 ◽

Vol 122 (21) ◽

pp. 2912-2912 ◽

Cited By ~ 1

Author(s):

Sankaranarayanan Kannan ◽

Mandy A Hall ◽

Leonard S Golfman ◽

Patrick A Zweidler-McKay

Keyword(s):

Cell Cycle ◽

Notch Signaling ◽

Growth Arrest ◽

Selective Inhibitor ◽

Cyclin B ◽

Cell Type ◽

Specific Effects ◽

Cell Cycle Regulator ◽

Cell Type Specific ◽

Novel Therapeutic

Abstract Background Notch is a well-known oncogene in T-ALL, yet appears to have tumor suppressor effects in B-ALL. These cell type-specific effects of Notch signaling mirror consequences seen in early lymphocyte development and raises the question of how Notch leads to such divergent consequences in closely related cell types. In exploring these Notch mechanisms we discovered a B-ALL specific Notch-mediated reduction in the cell cycle regulator Polo-like kinase-1 (PLK1), revealing a novel targetable kinase in B-ALL. Approach To explore the consequences of Notch-mediated down regulation of cell cycle regulator kinase PLK1, we targeted PLK1 kinase function with the novel PLK1-selective inhibitor poloxin in human B-ALL lines. Results PLK1 is highly expressed in B-ALL verses normal tissues (panel A), correlates with cyclin B expression, is expressed >2-fold higher in B-ALL with t(1;19) than other B-ALL samples, and may predict response of ALL to methotrexate. In our panel of human B-ALL cell lines poloxin induced G2/M growth arrest and decreased cell number by >80% (panel B), and decreased survival in B-ALL cells (>75% AnnexinV+, panel C). PLK1 inhibition led to tumor suppressor p53 stabilization, revealing >5-fold increase in p53 protein levels following poloxin treatment in B-ALL (panel D). Mechanistically, PLK1 inhibition leads to both cytoplasmic re-localization of cyclin B, disrupting the CDC2-cyclinB complex, as well as phosphorylation of p53 at Ser20, which destabilizes p53-MDM2 interaction and thus accumulation of p53. Conclusions While exploring the mechanisms of cell type-specific effects of Notch signaling in ALL, we have found a novel therapeutic target, the cell cycle regulator PLK1. Our findings reveal a novel therapeutic approach whereby PLK1-selective inhibition via poloxin induces growth arrest and apoptosis in human B-ALL via consequences on cyclin B and p53 pathways. Disclosures: No relevant conflicts of interest to declare.

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Follistatin-Like 1 Attenuation Suppresses Intervertebral Disc Degeneration in Mice through Interacting with TNF-α and Smad Signaling Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/6640751 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Shaoyi Wang ◽

Jianlu Wei ◽

Jie Shi ◽

Qiting He ◽

Xiaocong Zhou ◽

...

Keyword(s):

Intervertebral Disc ◽

Disc Degeneration ◽

Intervertebral Disc Degeneration ◽

Inflammatory Diseases ◽

Morphological Changes ◽

Intervertebral Discs ◽

Inflammatory Factors ◽

Wild Type ◽

Tnf Α

Background. Inflammation plays an important role in intervertebral disc degeneration (IDD). The protein follistatin-like 1 (FSTL1) plays a proinflammatory role in a variety of inflammatory diseases. Objectives. The purpose of this study was to investigate whether IDD could be delayed by inhibiting FSTL-1 expression. Methods. We established a puncture-induced IDD model in wild-type and FSTL-1+/- mice and collected intervertebral discs (IVDs) from the mice. Safranin O staining was used to detect cartilage loss of IVD tissue, and HE staining was used to detect morphological changes of IVD tissue. We measured the expression of FSTL-1 and related inflammatory indicators in IVD tissues by immunohistochemical staining, real-time PCR, and Western blotting. Results. In the age-induced model of IDD, the level of FSTL-1 increased with the exacerbation of degeneration. In the puncture-induced IDD model, FSTL-1-knockdown mice showed a reduced degree of degeneration compared with that of wild-type mice. Further experiments showed that FSTL-1 knockdown also significantly reduced the level of related inflammatory factors in IVD. In vitro experiments showed that FSTL-1 knockdown significantly reduced TNF-α-induced inflammation. Specifically, the expression levels of the inflammatory factors COX-2, iNOS, MMP-13, and ADAMTS-5 were reduced. Knockdown of FSTL-1 attenuated inflammation by inhibiting the expression of P-Smad1/5/8, P-Erk1/2, and P-P65. Conclusion. Knockdown of FSTL-1 attenuated inflammation by inhibiting the TNF-α response and Smad pathway activity and ultimately delayed IDD.

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Protective Effect of Polygonatum sibiricum Polysaccharides on Apoptosis, Inflammation, and Oxidative Stress in Nucleus Pulposus Cells of Rats with the Degeneration of the Intervertebral Disc

International Journal of Polymer Science ◽

10.1155/2019/8925807 ◽

2019 ◽

Vol 2019 ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Zhaohui Zhai ◽

Zhaoxin Li ◽

Zhonglei Ji ◽

Xiaosheng Lu

Keyword(s):

Oxidative Stress ◽

Intervertebral Disc ◽

Nucleus Pulposus ◽

Disc Degeneration ◽

Rat Model ◽

Intervertebral Disc Degeneration ◽

Intervertebral Discs ◽

New Drugs ◽

Nucleus Pulposus Cells ◽

And Oxidative Stress

Objective. Polygonatum sibiricum polysaccharide (PSP) has antioxidant activity, immune enhancement, and other biological properties. However, the effect of PSP on intervertebral disc degeneration has not been reported. In this study, we mainly investigated the effect of PSP on the apoptosis, inflammation, and oxidative stress of nucleus pulposus cells (NPCs) during the process of intervertebral disc degeneration. Methods. A rat NPC model induced by H2O2 was constructed. The CCK8 method was used to measure the effects of PSP on the apoptosis of rat NPCs induced by H2O2. The effects on the activity of SOD and content of MDA were also determined. The rat model of intervertebral disc degeneration was treated with PSP for 1 month, and the mRNA expression levels of IL-1β, COX2, iNOS, Col2α1, Col10α1, and MMP3 were measured by qPCR in the tissue of intervertebral disc. NPCs from the degenerated intervertebral discs were separated, and the cell viability was measured by the CCK8 method. The contents of SOD and MDA in NPCs were determined as well. Results. PSP significantly reduced the apoptosis of NPCs induced by H2O2, significantly increased the SOD content, and decreased the content of MDA in H2O2-induced NPCs. The expression level of IL-1β, COX2, and iNOS in the rat model with intervertebral disc degeneration was significantly downregulated after 1 month of PSP treatment. PSP treatment increased the expression of Col2α1 type and significantly decreased the expression of Col10α1 type collagen and MMP3 in rats with disc degeneration. PSP treatment significantly reduced NPC apoptosis and increased its SOD content and reduced MDA content, which is consistent with the results from cell-level experiments. Conclusion. PSP can effectively reduce the apoptosis, inflammation, and oxidative stress of H2O2-induced NPCs in rats with intervertebral disc degeneration and mitigate the progression of intervertebral disc degeneration, which has the potential to be developed as new drugs for the treatment of intervertebral disc degeneration.

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Long-term treatment with senolytic drugs Dasatinib and Quercetin ameliorates age-dependent intervertebral disc degeneration in mice

Nature Communications ◽

10.1038/s41467-021-25453-2 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Emanuel J. Novais ◽

Victoria A. Tran ◽

Shira N. Johnston ◽

Kayla R. Darris ◽

Alex J. Roupas ◽

...

Keyword(s):

Intervertebral Disc ◽

Disc Degeneration ◽

Intervertebral Disc Degeneration ◽

Chronic Back Pain ◽

The Elderly ◽

Term Treatment ◽

Specific Effects ◽

Long Term Treatment ◽

Age Dependent

AbstractIntervertebral disc degeneration is highly prevalent within the elderly population and is a leading cause of chronic back pain and disability. Due to the link between disc degeneration and senescence, we explored the ability of the Dasatinib and Quercetin drug combination (D + Q) to prevent an age-dependent progression of disc degeneration in mice. We treated C57BL/6 mice beginning at 6, 14, and 18 months of age, and analyzed them at 23 months of age. Interestingly, 6- and 14-month D + Q cohorts show lower incidences of degeneration, and the treatment results in a significant decrease in senescence markers p16INK4a, p19ARF, and SASP molecules IL-6 and MMP13. Treatment also preserves cell viability, phenotype, and matrix content. Although transcriptomic analysis shows disc compartment-specific effects of the treatment, cell death and cytokine response pathways are commonly modulated across tissue types. Results suggest that senolytics may provide an attractive strategy to mitigating age-dependent disc degeneration.

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Propionibacterium acnes Induces Intervertebral Disc Degeneration by Promoting iNOS/NO and COX-2/PGE2 Activation via the ROS-Dependent NF-κB Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2018/3692752 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12 ◽

Cited By ~ 7

Author(s):

Yazhou Lin ◽

Guoqing Tang ◽

Yucheng Jiao ◽

Ye Yuan ◽

Yuehuan Zheng ◽

...

Keyword(s):

Nitric Oxide ◽

Intervertebral Disc ◽

Disc Degeneration ◽

Intervertebral Disc Degeneration ◽

Propionibacterium Acnes ◽

Intervertebral Discs ◽

Cox 2 ◽

Underlying Mechanisms

Accumulating evidence suggests that Propionibacterium acnes (P. acnes) is a novel pathogenic factor promoting intervertebral disc degeneration (IVDD). However, the underlying mechanisms by which P. acnes induces IVDD have been unclear. In this study, we quantified the severity of IVDD, as well as the expressions of inducible nitric oxide synthase (iNOS)/nitric oxide (NO) and cyclooxygenase (COX-2)/prostaglandin (PGE2) in human intervertebral discs (IVDs) infected with P. acnes. Compared with P. acnes-negative IVDs, P. acnes-positive IVDs showed increased iNOS/NO and COX-2/PGE2 activity concomitant with more severe IVDD. In order to detect the potential correlation between iNOS/NO expression, COX-2/PGE2 expression, and IVDD, we developed a P. acnes-induced IVDD rat model and found that the upregulation of iNOS/NO and COX-2/PGE2 was essential to the occurrence of P. acnes-induced IVDD. This finding was supported by the fact that the inhibition of iNOS/NO and COX-2/PGE2 activity ameliorated IVDD significantly, as evidenced by restored aggrecan and collagen II expression both in vivo and in vitro. Mechanistically, we found that P. acnes induced iNOS/NO and COX-2/PGE2 expressions via a reactive oxygen species- (ROS-) dependent NF-κB cascade. Furthermore, NADPH oxidase participated in P. acnes-induced ROS, iNOS/NO, and COX-2/PGE2 expressions. Overall, these findings further validated the involvement of P. acnes in the pathology of IVDD and provided evidence that P. acnes-induced iNOS/NO and COX-2/PGE2 activation via the ROS-dependent NF-κB pathway is likely responsible for the pathology of IVDD.

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Mitochondrial quality control in intervertebral disc degeneration

Experimental & Molecular Medicine ◽

10.1038/s12276-021-00650-7 ◽

2021 ◽

Author(s):

Yu Song ◽

Saideng Lu ◽

Wen Geng ◽

Xiaobo Feng ◽

Rongjin Luo ◽

...

Keyword(s):

Quality Control ◽

Intervertebral Disc ◽

Disc Degeneration ◽

Intervertebral Disc Degeneration ◽

Molecular Mechanisms ◽

Cell Function ◽

Current Knowledge ◽

Mitochondrial Dynamics ◽

Intervertebral Discs ◽

Mitochondrial Quality Control

AbstractIntervertebral disc degeneration (IDD) is a common and early-onset pathogenesis in the human lifespan that can increase the risk of low back pain. More clarification of the molecular mechanisms associated with the onset and progression of IDD is likely to help establish novel preventive and therapeutic strategies. Recently, mitochondria have been increasingly recognized as participants in regulating glycolytic metabolism, which has historically been regarded as the main metabolic pathway in intervertebral discs due to their avascular properties. Indeed, mitochondrial structural and functional disruption has been observed in degenerated nucleus pulposus (NP) cells and intervertebral discs. Multilevel and well-orchestrated strategies, namely, mitochondrial quality control (MQC), are involved in the maintenance of mitochondrial integrity, mitochondrial proteostasis, the mitochondrial antioxidant system, mitochondrial dynamics, mitophagy, and mitochondrial biogenesis. Here, we address the key evidence and current knowledge of the role of mitochondrial function in the IDD process and consider how MQC strategies contribute to the protective and detrimental properties of mitochondria in NP cell function. The relevant potential therapeutic treatments targeting MQC for IDD intervention are also summarized. Further clarification of the functional and synergistic mechanisms among MQC mechanisms may provide useful clues for use in developing novel IDD treatments.

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Mangiferin Alleviates Mitochondrial ROS in Nucleus Pulposus Cells and Protects against Intervertebral Disc Degeneration via Suppression of NF-κB Signaling Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/6632786 ◽

2021 ◽

Vol 2021 ◽

pp. 1-27

Author(s):

Haichao Yu ◽

Guowei Hou ◽

Jiankang Cao ◽

Yanyu Yin ◽

Yunpeng Zhao ◽

...

Keyword(s):

Intervertebral Disc ◽

Mitochondrial Dysfunction ◽

Signaling Pathway ◽

Nucleus Pulposus ◽

Disc Degeneration ◽

Intervertebral Disc Degeneration ◽

Intervertebral Discs ◽

Nucleus Pulposus Cells ◽

Mitochondrial Ros ◽

Tnf Α

Intervertebral disc degeneration (IVDD), one of the most common clinical diseases worldwide, causes disc herniation and sciatica. Recent studies have identified the involvement of mitochondrial dysfunction, inflammatory responses, and extracellular matrix degradation in IVDD. Mangiferin is known to protect against various diseases by inhibiting oxidative stress, suppressing inflammation reaction, and relieving mitochondrial dysfunction. Whether mangiferin can alleviate IVDD remains to be elucidated. In the present study, human nucleus pulposus cells (HNPCs) and mouse intervertebral discs were cultured and stimulated with TNF-α, with or without treatment of mangiferin. Moreover, we established a rat needle puncture model and injected mangiferin into the intervertebral discs to verify its protective effect on IVDD. Furthermore, the activity of the NF-κB signaling pathway was tested in vitro. Our results indicated that mangiferin alleviated the inflammatory response and reversed the loss of major intervertebral disc components. Besides, mangiferin reduced reactive oxygen species production, ameliorated mitochondrial damage, and decreased the expression of apoptosis-related parameters in stimulation of TNF-α. In addition, mangiferin antagonized the activation of the NF-κB signaling pathway induced by TNF-α. Collectively, mangiferin antagonized mitochondrial ROS in NP cells and protected against IVDD by suppressing the activation of the NF-κB signaling pathway, which might provide a potential therapeutic instrument for IVDD.

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Mechanism of Long Noncoding RNA HOTAIR in Nucleus Pulposus Cell Autophagy and Apoptosis in Intervertebral Disc Degeneration

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2022/8504601 ◽

2022 ◽

Vol 2022 ◽

pp. 1-18

Author(s):

Shujun Zhang ◽

Sheng Song ◽

Wei Cui ◽

Xueguang Liu ◽

Zhenzhong Sun

Keyword(s):

Intervertebral Disc ◽

Nucleus Pulposus ◽

Disc Degeneration ◽

Noncoding Rna ◽

Intervertebral Disc Degeneration ◽

Intervertebral Discs ◽

Luciferase Reporter ◽

Blue Staining ◽

Tunel Staining ◽

Lncrna Hotair

Objective. Intervertebral disc degeneration (IDD) contributes to cervical and lumbar diseases. Long noncoding RNAs (lncRNAs) are implicated in IDD. This study explored the mechanism of lncRNA HOTAIR in IDD. Methods. Normal and degenerative nucleus pulposus (NP) cells were isolated from NP tissues obtained in intervertebral disc surgery. Cell morphology was observed by immunocytochemistry staining and toluidine blue staining. NP cell markers were detected by RT-qPCR. Proliferation was detected by MTT assay. Autophagy-related proteins were detected by Western blot. Autophagosome was observed by monodansylcadaverine fluorescence staining. Apoptosis was detected by TUNEL staining and flow cytometry. si-HOTAIR and/or miR-148a inhibitor was introduced into degenerative NP cells. Binding relationships among HOTAIR, miR-148a, and PTEN were predicted and verified by dual-luciferase reporter assay and RNA pull-down. Finally, IDD rat models were established. Rat caudal intervertebral discs were assessed by HE staining. Expressions of HOTAIR, miR-148a, and PTEN were determined by RT-qPCR. Results. HOTAIR was highly expressed in degenerative NP cells p < 0.05 . si-HOTAIR inhibited degenerative NP cell apoptosis and autophagy p < 0.05 . HOTAIR upregulated PTEN as a sponge of miR-148a. miR-148a was poorly expressed in degenerative NP cells. miR-148a deficiency partially reversed the inhibition of si-HOTAIR on degenerative NP cell autophagy and apoptosis (all p < 0.05 ). In vivo assay confirmed that si-HOTAIR impeded autophagy and apoptosis in intervertebral disc tissues, thus improving pathological injury in IDD rats (all p < 0.05 ). Conclusion. LncRNA HOTAIR promoted NP cell autophagy and apoptosis via promoting PTEN expression as a ceRNA of miR-148a in IDD.

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Reducing Inflammation and Vascular Invasion in Intervertebral Disc Degeneration via Cystathionine-γ-Lyase Inhibitory Effect on E-Selectin

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.741046 ◽

2021 ◽

Vol 9 ◽

Author(s):

Haoran Xu ◽

Kang Wei ◽

Jingyao Tu ◽

Yangmengfan Chen ◽

Yi He ◽

...

Keyword(s):

Intervertebral Disc ◽

Disc Degeneration ◽

Vascular Function ◽

Vascular Invasion ◽

Intervertebral Disc Degeneration ◽

Human Life ◽

Lumbar Disc ◽

Inhibitory Effect ◽

Intervertebral Discs ◽

Spinal Diseases

The incidence of degenerative spinal diseases, such as cervical spondylosis and thoracic and lumbar disc herniation, is increasing. These health problems have adversely affected human life and work. Surgical intervention is effective when intervertebral disc degeneration (IDD) causes nerve compression and/or severely limits daily activity. Early IDD patients generally do not require surgery. However, there is no effective method of impeding IDD progression. Thus, novel approaches to alleviating IDD deterioration are urgently required. Cystathionine-γ-lyase (CSE) and E-selectin (CD62E) are vital factors regulating vascular function and inflammation. However, their effects on IDD and vascular invasion in intervertebral discs (IVDs) are pending further exploration. Here, bioinformatics and human nucleus pulposus (NP) tissues analyses revealed that CSE was significantly downregulated and CD62E was upregulated in the NP tissues of IDD patients. We demonstrated that CSE overexpression, CD62E downregulation, and NF-κB (P65) inhibition mitigate inflammation and recover metabolic function in NP cells. Similarly, CSE attenuated vascular invasion induced by inflammatory irritation. Using a rat IDD model, we showed that CSE improved degeneration, inflammation, and microvascular invasion in NP tissue, whereas CD62E had the opposite effect. Taken together, our results indicated that the CSE/CD62E pathway could effectively improve the inflammatory environment and vascular invasion in IVD. Hence, the findings of this study propose a promising and valuable strategy for the treatment of patients with early IDD as well as postoperative adjuvant therapy in patients with severe IDD.

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