SIRT1-autophagy axis may inhibit oxidative stress-induced ferroptosis in human nucleus pulposus cells

ObjectiveThe aim of this study is to explore the role of Parkin in intervertebral disk degeneration (IDD) and its mitophagy regulation mechanism.Study design and methodsRat nucleus pulposus (NP) cells were stimulated with hydrogen peroxide (H2O2) to a mimic pathological condition. Apoptosis and mitophagy were assessed by Western blot, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and immunofluorescence staining. The CRISPR–dCas9–KRAB system was used to silence the expression of Parkin.ResultIn this study, we found that Parkin was downregulated in rat NP cells under oxidative stress. In addition, treatment with H2O2 resulted in mitochondrial dysfunction, autophagy inhibition, and a significant increase in the rate of apoptosis of NP cells. Meanwhile, mitophagy inhibition enhanced H2O2-induced apoptosis. Furthermore, repression of Parkin significantly attenuated mitophagy and exacerbated apoptosis.ConclusionThese results suggested that Parkin may play a protective role in alleviating the apoptosis of NP cells via mitophagy, and that targeting Parkin may provide a promising therapeutic strategy for the prevention of IDD.

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Long Noncoding RNA ANPODRT Overexpression Protects Nucleus Pulposus Cells from Oxidative Stress and Apoptosis by Activating Keap1-Nrf2 Signaling

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/6645005 ◽

2021 ◽

Vol 2021 ◽

pp. 1-17

Author(s):

Liang Kang ◽

Yueyang Tian ◽

Xing Guo ◽

Xu Chu ◽

Yuan Xue

Keyword(s):

Oxidative Stress ◽

Nucleus Pulposus ◽

Noncoding Rna ◽

Target Genes ◽

Nuclear Translocation ◽

Related Factor ◽

Nucleus Pulposus Cells ◽

Tert Butyl Hydroperoxide ◽

Antioxidative Stress ◽

Opposing Effects

Oxidative stress and subsequent nucleus pulposus (NP) cell apoptosis are important contributors to the development of intervertebral disc degeneration (IDD). Emerging evidences show that long noncoding RNAs (lncRNAs) play a role in the pathogenesis of IDD. In this study, we investigated the role of lncRNA ANPODRT (anti-NP cell oxidative damage-related transcript) in oxidative stress and apoptosis in human NP cells. We found that ANPODRT was downregulated in degenerative NP tissues and in NP cells treated with tert-butyl hydroperoxide (TBHP, the oxidative stress inducer). ANPODRT overexpression alleviated oxidative stress and apoptosis in NP cells exposed to TBHP, while ANPODRT knockdown exerted opposing effects. Mechanistically, ANPODRT facilitated nuclear factor E2-related factor 2 (Nrf2) accumulation and nuclear translocation and activated its target genes by disrupting the kelch-like ECH-associated protein 1- (Keap1-) Nrf2 association in NP cells. Nrf2 knockdown abolished the antioxidative stress and antiapoptotic effects of ANPODRT in NP cells treated with TBHP. Collectively, our findings suggest that ANPODRT protects NP cells from oxidative stress and apoptosis, at least partially, by activating Nrf2 signaling, implying that ANPODRT may be a potential therapeutic target for IDD.

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The REDD1/TXNIP Complex Accelerates Oxidative Stress-Induced Apoptosis of Nucleus Pulposus Cells through the Mitochondrial Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/7397516 ◽

2021 ◽

Vol 2021 ◽

pp. 1-22

Author(s):

Huipeng Yin ◽

Kun Wang ◽

Abhirup Das ◽

Gaocai Li ◽

Yu Song ◽

...

Keyword(s):

Oxidative Stress ◽

Intervertebral Disc ◽

Nucleus Pulposus ◽

Cell Apoptosis ◽

Redox Homeostasis ◽

Mitochondrial Pathway ◽

Nucleus Pulposus Cells ◽

Damage Response ◽

Induced Apoptosis ◽

Ivd Degeneration

The death of nucleus pulposus (NP) cells is an important cause of intervertebral disc (IVD) degeneration. Redox disturbance caused by dysfunctional mitochondria has been considered as a vital risk for NP cell survival. It is valuable to identify key proteins maintaining mitochondrial function in NP cells. A previous study found that regulated in development and DNA damage response 1 (REDD1) are upregulated during intervertebral disc degeneration and that REDD1 can cause NP cell apoptosis. Thus, the present study further explores the effect of REDD1 on IVD degeneration. Our results showed that REDD1 promotes NP cell apoptosis via the mitochondrial pathway. Importantly, REDD1 formed a complex with TXNIP to strengthen its own action, and the combination was consolidated under H2O2-induced oxidative stress. The combined inhibition of the REDD1/TXNIP complex was better than that of REDD1 or TXNIP alone in restoring cell proliferation and accelerating apoptosis. Moreover, p53 acts as the transcription factor of REDD1 to regulate the REDD1/TXNIP complex under oxidative stress. Altogether, our results demonstrated that the REDD1/TXNIP complex mediated H2O2-induced human NP cell apoptosis and IVD degeneration through the mitochondrial pathway. Interferences on these sites to achieve mitochondrial redox homeostasis may be a novel therapeutic strategy for oxidative stress-associated IVD degeneration.

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Dimethyl fumarate protects nucleus pulposus cells from inflammation and oxidative stress and delays the intervertebral disc degeneration

Experimental and Therapeutic Medicine ◽

10.3892/etm.2020.9399 ◽

2020 ◽

Vol 20 (6) ◽

pp. 1-1 ◽

Cited By ~ 1

Author(s):

Hainian Zhu ◽

Gang Chen ◽

Yuhua Wang ◽

Xuchen Lin ◽

Jingyuan Zhou ◽

...

Keyword(s):

Oxidative Stress ◽

Intervertebral Disc ◽

Nucleus Pulposus ◽

Disc Degeneration ◽

Intervertebral Disc Degeneration ◽

Dimethyl Fumarate ◽

Nucleus Pulposus Cells ◽

And Oxidative Stress

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Oxidative Stress Aggravates Apoptosis of Nucleus Pulposus Cells through m6A Modification of MAT2A Pre-mRNA by METTL16

Oxidative Medicine and Cellular Longevity ◽

10.1155/2022/4036274 ◽

2022 ◽

Vol 2022 ◽

pp. 1-15

Author(s):

Peng-Bo Chen ◽

Gui-Xun Shi ◽

Tao Liu ◽

Bo Li ◽

Sheng-Dan Jiang ◽

...

Keyword(s):

Oxidative Stress ◽

Animal Model ◽

Pilot Study ◽

Nucleus Pulposus ◽

Intervertebral Disc Degeneration ◽

Nucleus Pulposus Cell ◽

Nucleus Pulposus Cells ◽

Human Npcs

The process of intervertebral disc degeneration (IVDD) is complex, and its mechanism is considered multifactorial. Apoptosis of oxidative stressed nucleus pulposus cells (NPCs) should be a fundamental element in the pathogenesis of IVDD. In our pilot study, we found that the expression of MAT2A decreased, and METTL16 increased in the degenerative nucleus pulposus tissues. Previous studies have shown that the balance of splicing, maturation, and degradation of MAT2A pre-mRNA is regulated by METTL16 m6A modification. In the current study, we aimed to figure out whether this mechanism was involved in the aberrant apoptosis of NPCs and IVDD. Human NPCs were isolated and cultured under oxidative stress. An IVDD animal model was established. It showed that significantly higher METTL16 expression and lower MAT2A expression were seen in either the NPCs under oxidative stress or the degenerative discs of the animal model. MAT2A was inhibited with siRNA in vitro or cycloleucine in vivo. METTL16 was overexpressed with lentivirus in vitro or in vivo. Downregulation of MAT2A or upregulation of METTL16 aggravated nucleus pulposus cell apoptosis and disc disorganization. The balance of splicing, maturation, and degradation of MAT2A pre-mRNA was significantly inclined to degradation in the NPCs with the overexpression of METTL16. Increased apoptosis of NPCs under oxidative stress could be rescued by reducing the expression of METTL16 using siRNA with more maturation of MAT2A pre-mRNA. Collectively, oxidative stress aggravates apoptosis of NPCs through disrupting the balance of splicing, maturation, and degradation of MAT2A pre-mRNA, which is m6A modified by METTL16.

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