Progression Of Intervertebral Disc Degeneration Research Articles

SP1/CTR1-mediated oxidative stress-induced cuproptosis in intervertebral disc degeneration.

Intervertebral disc degeneration (IDD) is an age-related disease and is responsible for low back pain. Oxidative stress-induced cell death plays a fundamental role in IDD pathogenesis. Cuproptosis is a recently discovered form of programmed cell death dependent on copper availability. Whether cuproptosis is involved in IDD progression remains unknown. Herein, we established in vitro and in vivo models to investigate cuproptosis in IDD and the mechanisms by which oxidative stress interacts with copper sensitivity in nucleus pulposus cells (NPCs). We found that ferredoxin-1 (FDX1) content increased in both rat and human degenerated discs. Sublethal oxidative stress on NPCs led to increased FDX1 expression, tricarboxylic acid (TCA) cycle-related proteins lipoylation and aggregation, and cell death in the presence of Cu2+ at physiological concentrations, while FDX1 knockdown inhibited cell death. Since copper homeostasis is involved in copper-induced cytotoxicity, we investigated the role of copper transport-related proteins, including importer (CTR1) and efflux pumps (ATPase transporter, ATP7A, and ATP7B). CTR1 and ATP7A content increased under oxidative stress, and blocking CTR1 reduced oxidative stress/copper-induced TCA-related protein aggregation and cell death. Moreover, oxidative stress promoted the expression of specific protein 1 (SP1) and SP1-mediated CTR1 transcription. SP1 inhibition decreased cell death rates, preserved disc hydration, and alleviated tissue degeneration. This suggests that oxidative stress upregulates FDX1 expression and copper flux through promoting SP1-mediated CTR1 transcription, leading to increased TCA cycle-related protein aggregation and cuproptosis. This study highlights the importance of cuproptosis in IDD progression and provides a promising therapeutic target for IDD treatment.

An injectable anti-vascularization functionalized hydrogel for degenerative nucleus pulposus repair

Neovascularization and inflammatory cell invasion within the nucleus pulposus (NP) constitute pivotal pathological changes during the acceleration stage of intervertebral disc degeneration (IDD). Mesenchymal stem cells (MSCs), renowned for their remarkable capacity in intervertebral disc (IVD) regeneration, also exhibit the capability to secrete pro-angiogenic factors, expediting IDD progression under hypoxic conditions. Consequently, we developed a hydrogel comprised of methacrylated hyaluronic acid (HAMA), rat tail collagen I (COL), and MSCs, incorporating the vascular endothelial growth factor receptor (VEGFR) inhibitor cabozantinib (Cabo@HAMA-COL/MSCs hydrogel). This innovative construct aimed to facilitate NP regeneration while mitigating vascularization and inflammation. Our findings revealed that the hydrogel aptly mimicked the mechanical characteristics of NP tissue, exhibiting injectability, low cytotoxicity, and the preservation of the cellular phenotype of NP cells. Co-culturing of MSCs and human umbilical vein endothelial cells (HUVECs) promoted migration, tube formation, and sprouting of HUVECs, which will be inhibited by cabozantinib. In vivo experiments demonstrated that Cabo@HAMA-COL/MSCs hydrogel maintained disc height, protected NP, and alleviated vascularization and inflammation in a puncture-induced rat caudal IDD model. Consequently, our results substantiate that Cabo@HAMA-COL/MSCs hydrogel can prevent IDD degeneration by ameliorating the vascularization-inflammation pathological microenvironment, offering a promising therapeutic strategy for IDD.

CircEYA3 aggravates intervertebral disc degeneration through the miR-196a-5p/EBF1 axis and NF-κB signaling

Intervertebral disc degeneration (IDD) is a well-established cause of disability, and extensive evidence has identified the important role played by regulatory noncoding RNAs, specifically circular RNAs (circRNAs) and microRNAs (miRNAs), in the progression of IDD. To elucidate the molecular mechanism underlying IDD, we established a circRNA/miRNA/mRNA network in IDD through standardized analyses of all expression matrices. Our studies confirmed the differential expression of the transcription factors early B-cell factor 1 (EBF1), circEYA3, and miR-196a-5p in the nucleus pulposus (NP) tissues of controls and IDD patients. Cell proliferation, apoptosis, and extracellular mechanisms of degradation in NP cells (NPC) are mediated by circEYA3. MiR-196a-5p is a direct target of circEYA3 and EBF1. Functional analysis showed that miR-196a-5p reversed the effects of circEYA3 and EBF1 on ECM degradation, apoptosis, and proliferation in NPCs. EBF1 regulates the nuclear factor kappa beta (NF-кB) signalling pathway by activating the IKKβ promoter region. This study demonstrates that circEYA3 plays an important role in exacerbating the progression of IDD by modulating the NF-κB signalling pathway through regulation of the miR196a-5p/EBF1 axis. Consequently, a novel molecular mechanism underlying IDD development was elucidated, thereby identifying a potential therapeutic target for future exploration.

Regulatory mechanism of FCGR2A in macrophage polarization and its effects on intervertebral disc degeneration.

Intervertebral disc degeneration (IDD) poses a significant health burden, necessitating a deeper understanding of its molecular underpinnings. Transcriptomic analysis reveals 485 differentially expressed genes (DEGs) associated with IDD, underscoring the importance of immune regulation. Weighted gene co-expression network analysis (WGCNA) identifies a yellow module strongly correlated with IDD, intersecting with 197 DEGs. Protein-protein interaction (PPI) analysis identifies ITGAX, MMP9 and FCGR2A as hub genes, predominantly expressed in macrophages. Functional validation through in vitro and in vivo experiments demonstrates the pivotal role of FCGR2A in macrophage polarization and IDD progression. Mechanistically, FCGR2A knockdown suppresses M1 macrophage polarization and NF-κB phosphorylation while enhancing M2 polarization and STAT3 activation, leading to ameliorated IDD in animal models. This study sheds light on the regulatory function of FCGR2A in macrophage polarization, offering novel insights for IDD intervention strategies. KEY POINTS: This study unveils the role of FCGR2A in intervertebral disc (IVD) degeneration (IDD). FCGR2A knockdown mitigates IDD in cellular and animal models. Single-cell RNA-sequencing uncovers diverse macrophage subpopulations in degenerated IVDs. This study reveals the molecular mechanism of FCGR2A in regulating macrophage polarization. This study confirms the role of the NF-κB/STAT3 pathway in regulating macrophage polarization in IDD.

Omilancor mitigates the senescence of nucleus pulposus cells induced by DDP through targeting MAP2K6.

This study explores the potential of Omilancor in treating Intervertebral Disc Degeneration (IDD) through MAP2K6 targeting. We analyzed mRNA microarray datasets to pinpoint MAP2K6 as a key regulator implicated in IDD progression. Follow-up studies demonstrated that cisplatin (DDP) could prompt cellular senescence in vitro by upregulating MAP2K6 expression. Through molecular docking and other analyses, we identified Omilancor as a compound capable of binding to MAP2K6. This interaction effectively impeded the cellular senescence induced by DDP. We further showed that administration of Omilancor could significantly alleviate the degeneration of IVDs in annulus fibrosus puncture-induced rat model. Omilancor shows promise as a treatment for IDD by targeting MAP2K6-mediated cellular senescence.

Circular RNA CircFOXO3 Functions as a Competitive Endogenous RNA for Acid-Sensing Ion Channel Subunit 1 Mediating Oxeiptosis in Nucleus Pulposus.

Oxeiptosis is a reactive oxygen species (ROS)-induced pathway of cell death. The involvement of circular RNAs (circRNAs) has been confirmed in the incidence and progression of intervertebral disc degeneration (IVDD). However, whether oxeiptosis occurs in IVDD and how circRNAs regulate oxeiptosis is still unclear. In this study, we discovered that oxeiptosis could be induced in nucleus pulposus cells (NPCs), and circFOXO3 was significantly upregulated after oxeiptosis induction. Transfection using circFOXO3 small interfering RNA (siRNA) significantly inhibited oxeiptosis in NPCs. Mechanistically, circFOXO3 upregulated acid-sensing ion channel subunit 1 (ASIC1) expression by functioning as a molecular sponge for miR-185-3p and miR-939-5p. Subsequent rescue experiments validated that circFOXO3 could regulate oxeiptosis in NPCs via the miR-185-3p/miR-939-5p-ASIC1 axis. Further research on ASIC1 functions indicated that this regulation was achieved by affecting the Calcium ion (Ca2+) influx mediated by ASIC1. A mouse IVDD model was established, and silencing circFOXO3 in vivo was found to inhibit IVDD development and the activation of the oxeiptosis-related pathway. Overall, circFOXO3 is one of the factors contributing to the progression of IVDD by mediating oxeiptosis.

Integrated bioinformatics analysis of ferroptosis-related gene signature in inflammation and immunity in intervertebral disc degeneration

Ferroptosis has recently been shown to play a significant role in the progression of intervertebral disk degeneration (IDD), although the underlying mechanism is still unknown. The objective of this work was to use stringent bioinformatic techniques to clarify the crucial roles played by genes associated with ferroptosis in the emergence of IDD. For additional study, the microarray data pertinent to the IDD were acquired from the Gene Expression Omnibus database. The ferroptosis-related and IDD-related genes (FIDDRGs) were identified using a variety of bioinformatic techniques, which were also used to carry out function enrichment analysis, protein–protein correlation analysis, build the correlation regulatory network, and examine the potential connections between ferroptosis and immune abnormalities and inflammatory responses in IDD. A total of 16 FIDDRGs were eliminated for the further function enrichment analysis, and 10 hub FIDDRGs were chosen to build the correlation regulatory network. Hub FIDDRGs were shown to be highly associated with M2 macrophages and hub inflammatory response-related genes in IDD. When seen as a whole, our findings can give fresh perspectives on the mechanistic studies of ferroptosis in the emergence of IDD and new prospective targets for the therapeutic approaches.

Identification and validation of ferroptosis-related lncRNA signature in intervertebral disc degeneration

Low back pain influences people of every age and is one of the major contributors to the global cost of illness. Intervertebral disc degeneration (IVDD) is a major contributor to low back pain, but its pathogenesis is unknown. Recently, ferroptosis has been shown to have a substantial role in modulating IVDD progression. However, the function of ferroptosis-related long non-coding RNAs (lncRNAs) has rarely been reported in IVDD. Consequently, the research was conducted to explore the ferroptosis-related lncRNA signature in the IVDD occurrence and development. We analyzed two datasets (GSE167199 and GSE167931) archived in the NCBI Gene Expression Omnibus (GEO) public database. We screened differentially expressed genes (DEGs) and differentially expressed lncRNAs (DELncs) in these datasets using the limma package. Ferroptosis-related genes (FRGs) were derived from the FerrDb V2 website and the intersection of DEGs and FRGs was considered as differentially expressed ferroptosis-related genes (DFGs). These genes were then subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis. Correlations between DFGs and DELncs were shown by Pearson test to determine differential expression of ferroptosis-related lncRNAs. The Pearson test showed that CPEB1-HTR2A-AS1 and ACSL3-DNAJC27-AS1 pairs had correlation coefficients over 0.9. Twenty ferroptosis-related lncRNAs were identified and validated in IVDD. Eight of these lncRNAs were upregulated in IVDD nucleus pulposus cells, including HTR2A-AS1, MIF-AS1, SLC8A1-AS1, LINC00942, DUXAP8, LINC00161, LUCAT1 and LINC01615. Twelve were downregulated in IVDD nucleus pulposus cells, including DNAJC27-AS1, H19, LINC01588, LINC02015, FLNC1, CARMN, PRKG1-AS1, APCDD1L-DT, LINC00839, LINC00536, LINC00710 and LINC01535. Eighteen of the 20 lncRNAs (excluding H19 and LUCAT1) were identified as ferroptosis-related lncRNAs for the first time and verified in IVDD. We have identified a ferroptosis-related lncRNA signature involved in IVDD and revealed a close relationship between CPEB1 and HTR2A-AS1, and between ACSL3 and DNAJC27-AS1. Our findings indicate that ferroptosis-related lncRNAs are a new target set for the early detection and therapy of IVDD.

Thread-structural microneedles loaded with engineered exosomes for annulus fibrosus repair by regulating mitophagy recovery and extracellular matrix homeostasis

Low back pain is among the most grave public health concerns worldwide and the major clinical manifestation of intervertebral disc degeneration (IVDD). The destruction of annulus fibrosus (AF) is the primary cause of IVDD. A sustainable and stable treatment system for IVDD is lacking because of the special organizational structure and low nutrient supply of AF. We here found that IVDD results in the impaired mitochondrial function of AF tissue, and mitochondrial autophagy (mitophagy) plays a protective role in this process. We therefore reported a thread-structural microneedle (T-MN) matching the ring structure of AF. Based on the adsorption effect of laminin, our T-MN could load with bone marrow mesenchymal stem cell-derived exosomes to envelope the regulating mitophagy microRNA (miRNA 378), named as T-MN@EXO@miR−378. In general, we offered in situ locking in the defect site of AF to prevent nucleus pulposus leakage and promoted AF repair. The design of the thread structure was aimed at bionically matching the layered AF structure, thereby providing stronger adhesion. The T-MN@EXO@miR−378 effectively attached to AF and slowly released therapeutic engineered exosomes, and prevented IVDD progression by restoring mitophagy, promoting AF cell proliferation and migration, and inhibiting the pathological remodeling of the extracellular matrix. This functional system can be used as an excellent tool for sustained drug release and has a certain prospect in substituting the conventional treatment of IVDD.

Maslinic acid alleviates intervertebral disc degeneration by inhibiting the PI3K/AKT and NF-κB signaling pathways.

Intervertebral disc degeneration (IDD) is the cause of low back pain (LBP), and recent research has suggested that inflammatory cytokines play a significant role in this process. Maslinic acid (MA), a natural compound found in olive plants ( Olea europaea), has anti-inflammatory properties, but its potential for treating IDD is unclear. The current study aims to investigate the effects of MA on TNFα-induced IDD in vitro and in other in vivo models. Our findings suggest that MA ameliorates the imbalance of the extracellular matrix (ECM) and mitigates senescence by upregulating aggrecan and collagen II levels as well as downregulating MMP and ADAMTS levels in nucleus pulposus cells (NPCs). It can also impede the progression of IDD in rats. We further find that MA significantly affects the PI3K/AKT and NF-κB pathways in TNFα-induced NPCs determined by RNA-seq and experimental verification, while the AKT agonist Sc-79 eliminates these signaling cascades. Furthermore, molecular docking simulation shows that MA directly binds to PI3K. Dysfunction of the PI3K/AKT pathway and ECM metabolism has also been confirmed in clinical specimens of degenerated nucleus pulposus. This study demonstrates that MA may hold promise as a therapeutic agent for alleviating ECM metabolism disorders and senescence to treat IDD.

Ginsenoside Rg1 relieves rat intervertebral disc degeneration and inhibits IL-1β-induced nucleus pulposus cell apoptosis and inflammation via NF-κB signaling pathway

The study aimed to investigate the effect of ginsenoside Rg1 on intervertebral disc degeneration (IVDD) in rats and IL-1β-induced nucleus pulposus (NP) cells, and explore its underlying mechanism. Forty IVDD rat models were divided into the IVDD group, low-dose (L-Rg1) group (intraperitoneal injection of 20 mg/kg/d ginsenoside Rg1), medium-dose (M-Rg1) group (intraperitoneal injection of 40 mg/kg/d ginsenoside Rg1), and high-dose (H-Rg1) group (intraperitoneal injection of 80 mg/kg/d ginsenoside Rg1). The pathological change was observed by HE and safranin O-fast green staining. The expression of IL-1β, IL-6, TNF-α, MMP3, aggrecan, and collagen II was detected. The expression of NF-κB p65 in IVD tissues was detected. Rat NP cells were induced by IL-1β to simulate IVDD environment and divided into the control group, IL-1β group, and 20, 50, and 100 µmol/L Rg1 groups. The cell proliferation activity, the apoptosis, and the expression of IL-6, TNF-α, MMP3, aggrecan, collagen II, and NF-κB pathway–related protein were detected. In IVDD rats, ginsenoside Rg1 improved the pathology of IVD tissues; suppressed the expression of IL-1β, IL-6, TNF-α, aggrecan, and collagen II; and inhibited the expression of p-p65/p65 and nuclear translocation of p65, to alleviate the IVDD progression. In the IL-1β-induced NP cells, ginsenoside Rg1 also improved the cell proliferation and inhibited the apoptosis and the expression of IL-6, TNF-α, aggrecan, collagen II, p-p65/p65, and IκK in a dose-dependent manner. Ginsenoside Rg1 alleviated IVDD in rats and inhibited apoptosis, inflammatory response, and ECM degradation in IL-1β-induced NP cells. And Rg1 may exert its effect via inhibiting the activation of NF-κB signaling pathway.

Shared and Compartment-Specific Processes in Nucleus Pulposus and Annulus Fibrosus During Intervertebral Disc Degeneration.

Elucidating how cell populations promote onset and progression of intervertebral disc degeneration (IDD) has the potential to enable more precise therapeutic targeting of cells and mechanisms. Single-cell RNA-sequencing (scRNA-seq) is performed on surgically separated annulus fibrosus (AF) (19,978; 26,983 cells) and nucleus pulposus (NP) (20,884; 24,489 cells) from healthy and diseased human intervertebral discs (IVD). In both tissue types, depletion of cell subsets involved in maintenance of healthy IVD is observed, specifically the immature cell subsets - fibroblast progenitors and stem cells - indicative of an impairment of normal tissue self-renewal. Tissue-specific changes are also identified. In NP, several fibrotic populations are increased in degenerated IVD, indicating tissue-remodeling. In degenerated AF, a novel disease-associated subset is identified, which expresses disease-promoting genes. It is associated with pathogenic biological processes and the main gene regulatory networks include thrombospondin signaling and FOXO1 transcription factor. In NP and AF cells thrombospondin protein promoted expression of genes associated with TGFβ/fibrosis signaling, angiogenesis, and nervous system development. The data reveal new insights of both shared and tissue-specific changes in specific cell populations in AF and NP during IVD degeneration. These identified mechanisms and molecules are novel and more precise targets for IDD prevention and treatment.

From hyperglycemia to intervertebral disc damage: exploring diabetic-induced disc degeneration.

The incidence of lumbar disc herniation has gradually increased in recent years, and most patients have symptoms of low back pain and nerve compression, which brings a heavy burden to patients and society alike. Although the causes of disc herniation are complex, intervertebral disc degeneration (IDD) is considered to be the most common factor. The intervertebral disc (IVD) is composed of the upper and lower cartilage endplates, nucleus pulposus, and annulus fibrosus. Aging, abnormal mechanical stress load, and metabolic disorders can exacerbate the progression of IDD. Among them, high glucose and high-fat diets (HFD) can lead to fat accumulation, abnormal glucose metabolism, and inflammation, which are considered important factors affecting the homeostasis of IDD. Diabetes and advanced glycation end products (AGEs) accumulation- can lead to various adverse effects on the IVD, including cell senescence, apoptosis, pyroptosis, proliferation, and Extracellular matrix (ECM) degradation. While current research provides a fundamental basis for the treatment of high glucose-induced IDD patients. further exploration into the mechanisms of abnormal glucose metabolism affecting IDD and in the development of targeted drugs will provide the foundation for the effective treatment of these patients. We aimed to systematically review studies regarding the effects of hyperglycemia on the progress of IDD.

Therapeutic factors and biomaterial-based delivery tools for degenerative intervertebral disc repair.

Intervertebral disc degeneration (IDD) is the main cause of low back pain (LBP), which significantly impacts global wellbeing and contributes to global productivity declines. Conventional treatment approaches, encompassing conservative and surgical interventions, merely serve to postpone the advancement of IDD without offering a fundamental reversal. Consequently, there is an urgent demand for an effective approach to prevent the progression of IDD. Recent investigations focusing on the treatment of IDD utilizing diverse bioactive substances integrated within various biomaterials have exhibited promising outcomes. Various bioactive substances, encompassing conventional small molecule drugs, small molecule nucleic acids, and cell therapies, exhibit distinct capacities for repairing IDD. Additionally, various biological material delivery systems, such as nano micelles, microspheres, and hydrogels, possess diverse biological and release characteristics. Consequently, these diverse materials and drugs hold promise for advancing the treatment of IDD. This article aims to provide a concise overview of the IDD process and investigate the research advancements in biomaterials and bioactive substances for IDD treatment, delving into their mechanisms.

Nucleus pulposus cells regulate macrophages in degenerated intervertebral discs via the integrated stress response-mediated CCL2/7-CCR2 signaling pathway

Lower back pain (LBP), which is a primary cause of disability, is largely attributed to intervertebral disc degeneration (IDD). Macrophages (MΦs) in degenerated intervertebral discs (IVDs) form a chronic inflammatory microenvironment, but how MΦs are recruited to degenerative segments and transform into a proinflammatory phenotype remains unclear. We evaluated chemokine expression in degenerated nucleus pulposus cells (NPCs) to clarify the role of NPCs in the establishment of an inflammatory microenvironment in IDD and explored the mechanisms. We found that the production of C-C motif chemokine ligand 2 (CCL2) and C-C motif chemokine ligand 7 (CCL7) was significantly increased in NPCs under inflammatory conditions, and blocking CCL2/7 and their receptor, C-C chemokine receptor type 2(CCR2), inhibited the inductive effects of NPCs on MΦ infiltration and proinflammatory polarization. Moreover, activation of the integrated stress response (ISR) was obvious in IDD, and ISR inhibition reduced the production of CCL2/7 in NPCs. Further investigation revealed that activating Transcription Factor 3 (ATF3) responded to ISR activation, and ChIP-qPCR verified the DNA-binding activity of ATF3 on CCL2/7 promoters. In addition, we found that Toll-like receptor 4 (TLR4) inhibition modulated ISR activation, and TLR4 regulated the accumulation of mitochondrial reactive oxygen species (mtROS) and double-stranded RNA (dsRNA). Downregulating the level of mtROS reduced the amount of dsRNA and ISR activation. Deactivating the ISR or blocking CCL2/7 release alleviated inflammation and the progression of IDD in vivo. Moreover, MΦ infiltration and IDD were inhibited in CCR2-knockout mice. In conclusion, this study highlights the critical role of TLR4/mtROS/dsRNA axis-mediated ISR activation in the production of CCL2/7 and the progression of IDD, which provides promising therapeutic strategies for discogenic LBP.

Network Pharmacology with Metabolomics Study to Reveal the Mechanisms of Bushen Huoxue Formula in Intervertebral Disc Degeneration Treatment.

Intervertebral disc degeneration (IVDD) is a pathophysiological process that leads to severe back pain or neurological deficits. The Bushen Huoxue Formula (BSHXF) is a traditional herbal remedy widely used to treat diseases related to IVDD. However, its pharmacological mechanism needs further exploration. This study aimed to elucidate the mechanisms through which BSHXF treats IVDD-related diseases by integrating metabolomics with network pharmacology. Network pharmacology was utilized to identify potential targets of BSHXF against IVDD. Additionally, an animal model of needle puncture-induced disc degeneration was established to assess the effect of BSHXF. Mice were randomly assigned to the sham group, model group, and BSHXF group. Various techniques, including PCR, CCK-8 assay, MRI, histological examinations, and immunohistochemical analyses, were employed to evaluate degenerative and oxidative stress conditions in mouse disc tissue and cultured nucleus pulposus (NP) cells. UHPLC-HRMS/MS was used to differential distinct metabolites in the disc tissue from different groups, and MetaboAnalyst 5.0 was employed to enrich the metabolic pathways. Through network pharmacology, 15 core proteins were identified through protein-protein interaction (PPI) network construction. Functional enrichment analysis highlighted the critical role of BSHXF in addressing IVDD by influencing the response to oxidative stress. Furthermore, experimental evidence demonstrated that BSHXF significantly improved the pathological progression of IVDD and increased oxidative stress markers SOD-1 and GPX1, both in the disc degeneration model and cultured NP cells. Metabolomics identified differential metabolites among the three groups, revealing 15 metabolic pathways between the sham and model groups, and 13 metabolic pathways enriched between the model and BSHXF groups. This study, integrating network pharmacology and metabolomics, suggests that BSHXF can alleviate IVDD progression by modulating oxidative stress. Key metabolic pathways associated with BSHXF-mediated reduction of oxidative stress include the citrate cycle, cysteine and methionine metabolism, alanine, aspartate and glutamate metabolism, glycine, serine and threonine metabolism, D-glutamine and D-glutamate metabolism, glutathione metabolism, and tryptophan metabolism. While this research demonstrates the therapeutic potential of BSHXF in reducing oxidative stress levels in IVDD, further research is needed to thoroughly understand its underlying mechanisms.

Network Pharmacology and Experimental Validation to Elucidate the Pharmacological Mechanisms of Luteolin Against Chondrocyte Senescence.

Luteolin, a flavonoid found in various medicinal plants, has shown promising antioxidant, anti-inflammatory, and anti-aging properties. The cartilaginous endplate (CEP) represents a crucial constituent of the intervertebral disc (IVD), assuming a pivotal responsibility in upholding both the structural and functional stability of the IVD. Exploring the precise mechanism underlying the protective effects of luteolin against senescence and degeneration of endplate chondrocytes (EPCs). Relevant targets associated with luteolin and aging were obtained from publicly available databases. To ascertain cellular functions and signaling pathways, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were employed. Core genes were identified through the construction of a protein-protein interaction (PPI) network. Molecular docking (MD) was utilized to assess the binding affinity of luteolin to these core genes. Finally, the impact of luteolin on the senescence and degeneration of EPCs was evaluated in an in vitro cellular senescence model induced by tert-butyl hydroperoxide (TBHP). There are 145 overlapping targets between luteolin and senescence. Analysis using GO revealed that these targets primarily participate in cellular response to oxidative stress and reactive oxygen species. KEGG analysis demonstrated that these markers mainly associate with signaling pathways such as p53 and PI3K-Akt. MD simulations exhibited luteolin's binding affinity to P53, Cyclin-dependent kinase (CDK)2, and CDK4. Cell cycle, cell proliferation, and β- galactosidase assays confirmed that luteolin mitigated senescence in SW1353 cells. Western blot assays exhibited that luteolin significantly suppressed the expression of Matrix Metallopeptidase (MMP) 13, P53, and P21, while concurrently promoting CDK2, CDK4, and Collagen Type II Alpha 1 (COL2A1) expression. In summary, luteolin demonstrated beneficial properties against aging and degeneration in EPCs, offering novel insights to mitigate the progression of intervertebral disc degeneration (IVDD).

Disassembly of the TRIM56-ATR complex promotes cytoDNA/cGAS/STING axis-dependent intervertebral disc inflammatory degeneration.

As the leading cause of disability worldwide, low back pain (LBP) is recognized as a pivotal socioeconomic challenge to the aging population and is largely attributed to intervertebral disc degeneration (IVDD). Elastic nucleus pulposus (NP) tissue is essential for the maintenance of IVD structural and functional integrity. The accumulation of senescent NP cells with an inflammatory hypersecretory phenotype due to aging and other damaging factors is a distinctive hallmark of IVDD initiation and progression. In this study, we reveal a mechanism of IVDD progression in which aberrant genomic DNA damage promoted NP cell inflammatory senescence via activation of the cyclic GMP-AMP synthase/stimulator of IFN genes (cGAS/STING) axis but not of absent in melanoma 2 (AIM2) inflammasome assembly. Ataxia-telangiectasia-mutated and Rad3-related protein (ATR) deficiency destroyed genomic integrity and led to cytosolic mislocalization of genomic DNA, which acted as a powerful driver of cGAS/STING axis-dependent inflammatory phenotype acquisition during NP cell senescence. Mechanistically, disassembly of the ATR-tripartite motif-containing 56 (ATR-TRIM56) complex with the enzymatic liberation of ubiquitin-specific peptidase 5 (USP5) and TRIM25 drove changes in ATR ubiquitination, with ATR switching from K63- to K48-linked modification, c thereby promoting ubiquitin-proteasome-dependent dynamic instability of ATR protein during NP cell senescence progression. Importantly, an engineered extracellular vesicle-based strategy for delivering ATR-overexpressing plasmid cargo efficiently diminished DNA damage-associated NP cell senescence and substantially mitigated IVDD progression, indicating promising targets and effective approaches to ameliorate the chronic pain and disabling effects of IVDD.

Protective effects of Shensuitongzhi formula on intervertebral disc degeneration via downregulation of NF-κB signaling pathway and inflammatory response

Low back pain (LBP) is a common orthopedic disease over the world. Lumbar intervertebral disc degeneration (IDD) is regarded as an important cause of LBP. Shensuitongzhi formula (SSTZF) is a drug used in clinical treatment for orthopedic diseases. It has been found that SSTZF can have a good treatment for IDD. But the exact mechanism has not been clarified. The results showed that SSTZF protects against LSI-induced degeneration of cartilage endplates and intervertebral discs. Meanwhile, SSTZF treatment dramatically reduces the expression of inflammatory factor as well as the expression of catabolism protein and upregulates the expression of anabolism protein in LSI-induced mice. In addition, SSTZF delayed the progression of LSI-induced IDD via downregulation the level of NF-κB signaling key gene RELA and phosphorylation of key protein P65 in endplate chondrocytes. Our study has illustrated the treatment as well as the latent mechanism of SSTZF in IDD.

Polyphenols as Potential Antioxidants for the Treatment of Intervertebral Disc Degeneration.

Intervertebral disc degeneration (IDD) is a common musculoskeletal system disease, which is one of the most important causes of low back pain. Despite the high prevalence of IDD, current treatments are limited to relieving symptoms, and there are no effective therapeutic agents that can block or reverse the progression of IDD. Oxidative stress, the result of an imbalance between the production of reactive oxygen species (ROS) and clearance by the antioxidant defense system, plays an important role in the progression of IDD. Polyphenols are antioxidant compounds that can inhibit ROS production, which can scavenge free radicals, reduce hydrogen peroxide production, and inhibit lipid oxidation in nucleus pulposus (NP) cells and IDD animal models. In this review, we discussed the antioxidant effects of polyphenols and their regulatory role in different molecular pathways associated with the pathogenesis of IDD, as well as the limitations and future prospects of polyphenols as a potential treatment of IDD.