Process Of Intervertebral Disc Degeneration Research Articles

Revisiting miR-155 in intervertebral disc degeneration: blood cell signature and local cell-free profiles

We unraveled the expression profiles of coding-noncoding RNAs in intervertebral disc degeneration (IDD). However, it remains elusive regarding miR-155 expression in peripheral blood mononuclear cells (PBMCs) and local extracellular space in IDD. The study aimed for investigating the miR-155 expression of PBMCs, extracellular miRNAs (ex-miRNAs) of human nucleus pulposus (NP) tissues, and morphological changes of cell death in the IDD process. Here, we harvested peripheral blood and NP samples from scoliosis and IDD patients as control and degenerative groups, respectively. Then standard Ficoll density-gradient centrifugation was used to isolate PBMCs. The two subpopulations of PBMCs were divided based on the cellular difference in adherence, i.e., monocytes/ macrophages and lymphocytes. Quantitative real-time PCR was used to evaluate miR-155 relative expression in PBMCs. ex-miRNAs were screened by comparison between GSE19943, GSE63492, and extracellular RNA (exRNA) atlas. The morphological changes of cell death subtypes in IDD were observed in transmission electron microscopy (TEM). Results indicate that the lower expression of miR-155 in PBMCs from IDD patients ascribed to alterations in monocytes/macrophages. Moreover, we identified 594 shared hsa-miRNAs as the intracellular miRNA expression profile and 258 miRNAs as the ex-miRNA expression profile in human NP tissue. miR-155 was amongst intracellular miRNAs in NP. TEM observation presented multiple endocytic secretory vesicles within human NP cells, implicating exosome transporting machinery. Typical necroptosis and pyroptosis were noted in human NP. Collectively, this study reveals miR-155 expression in PBMCs from IDD patients. Moreover, we propose ex-miRNA expression profile and necroptosis/pyroptosis in human NP tissue, shedding novel light on the etiology of IDD.

Revisiting miR-155 in intervertebral disc degeneration: blood cell signature and local cell-free profiles

We unraveled the expression profiles of coding-noncoding RNAs in intervertebral disc degeneration (IDD). However, it remains elusive regarding miR-155 expression in peripheral blood mononuclear cells (PBMCs) and local extracellular space in IDD. The study aimed for investigating the miR-155 expression of PBMCs, extracellular miRNAs (ex-miRNAs) of human nucleus pulposus (NP) tissues, and morphological changes of cell death in the IDD process. Here, we harvested peripheral blood and NP samples from scoliosis and IDD patients as control and degenerative groups, respectively. Then standard Ficoll density-gradient centrifugation was used to isolate PBMCs. The two subpopulations of PBMCs were divided based on the cellular difference in adherence, i.e., monocytes/ macrophages and lymphocytes. Quantitative real-time PCR was used to evaluate miR-155 relative expression in PBMCs. ex-miRNAs were screened by comparison between GSE19943, GSE63492, and extracellular RNA (exRNA) atlas. The morphological changes of cell death subtypes in IDD were observed in transmission electron microscopy (TEM). Results indicate that the lower expression of miR-155 in PBMCs from IDD patients ascribed to alterations in monocytes/macrophages. Moreover, we identified 594 shared hsa-miRNAs as the intracellular miRNA expression profile and 258 miRNAs as the ex-miRNA expression profile in human NP tissue. miR-155 was amongst intracellular miRNAs in NP. TEM observation presented multiple endocytic secretory vesicles within human NP cells, implicating exosome transporting machinery. Typical necroptosis and pyroptosis were noted in human NP. Collectively, this study reveals miR-155 expression in PBMCs from IDD patients. Moreover, we propose ex-miRNA expression profile and necroptosis/pyroptosis in human NP tissue, shedding novel light on the etiology of IDD.

The Genetic Association Identified Between Intervertebral Disc Degeneration and Associated Risk Factors Based on a Systems Biology Approach

Genetic cross-over study of intervertebral disc degeneration (IDD) and its associated risk factors. The purpose is to identify molecular biomarkers that may be involved in the IDD process and to provide effective recommendations in combination with drug analysis via systems biology methods. The pathogenesis and genetic links of IDD are still unclear. Related research is mainly based on a single data set or gene, and the impact of related risk factors on IDD is often ignored. Identifying disease-associated biomarkers and therapeutic targets through a systems biology approach that Integrative network-based gene and multi-omics analysis. In this study, the differential expression of genes was analyzed through NCBI datasets, followed by enrichment analysis. The central protein was identified through the establishment of protein-protein interaction (PPI) network. Key genes were screened out by VENN diagram and reasonable suggestions were put forward based on gene-chemical drug analysis. The IDD database analysis revealed 669 differentially expressed genes (DEGs) which were 22, 26, 168, 5, 38, 36, and 16 common DEGs with AG, SM, DEP, NAD, CED, OB, and HFD, respectively. GO and KEGG enrichment analysis may reveal the pathway by which these DEGs were involved. PPI network identified 10 central proteins including CCNB1, RETN, HMMR, BUB1, MPO, OIP5, HP, KIF11, BUB1B, and CDC25A. Three key genes BUB1, BUB1B, and CCNB1 were screened out and their expression might be related to the pathogenesis of IDD. According to the three chemical Dexamethasone, Nicotine, and Resvera-trol obtained from the analysis of genes-chemical drugs, reasonable treatment suggestions were put forward. Genetic association between IDD and risk factors in the general population was revealed by association network. Important gene-related molecular pathways and chemical drugs closely related to IDD have been found. Further study can provide guidance for the treatment and prognosis of IDD.Level of Evidence: N/A.

Polarization of infiltrating macrophages in the outer annulus fibrosus layer associated with the process of intervertebral disc degeneration and neural ingrowth in the human cervical spine

BACKGROUND CONTEXTAs no infiltrating macrophages exist in healthy discs, understanding the role of infiltrating macrophages including their polarity (M1 and M2 phenotypes) in intervertebral discs (IVDs) is important in the assessment of the pathomechanisms of disc degeneration. PURPOSETo determine the relationship between infiltrating macrophage polarization and the progression of human cervical IVD degeneration. STUDY DESIGNHistopathological study using harvested human cervical IVDs. METHODSIVDs collected during anterior cervical decompression from 60 patients were subjected to immunostaining and immunoblotting. The samples were classified as type 0–3 according to the percentage of CD16- and CD206-positive cells to CD68-positive cells in the outer annulus fibrosus layer. The number of vessels and nerve fibers and the severity of chronic inflammation with a focus on inflammatory cell infiltration, fibrosis, and capillary proliferation were also assessed. RESULTSThe number of CD16-positive cells was the highest in type 2 IVDs, and was suppressed following the infiltration of CD206-positive cells. The degree of chronic inflammation was significantly higher in type 2 and type 3 IVDs, and the number of nerve fibers was significantly higher in type 3 IVDs. The endothelial cells of small vessels were positive for nerve growth factor, brain-derived neurotrophic factor, and neurotrophin-3 expression. Staining for tropomyosin receptor kinase (Trk)-A, Trk-B, and Trk-C was positive in aberrant fibers. In immunoblot analysis, the expression levels of these neurotrophic factors and receptors were significantly higher in type 2 and 3 IVDs. CONCLUSIONSThe polarity of macrophages around newly developed microvasculature might be altered with cervical IVD degeneration. A higher number of infiltrating M1 macrophages around the vessels was associated with chronic inflammation; however, their number got suppressed following the infiltration of M2 macrophages. The expression of neurotrophins in the capillaries of small vessels might contribute to neural ingrowth into degenerated IVDs. CLINICAL SIGNIFICANCEClarifying macrophages polarity change around new microvasculature associated with progression of IVD degeneration could enhance our understanding of the underlying mechanisms of neural ingrowth into degenerated IVDs and lead to development of a novel therapeutic target for prevention of IVD.

AMPK as a Potential Therapeutic Target for Intervertebral Disc Degeneration.

As the principal reason for low back pain, intervertebral disc degeneration (IDD) affects the health of people around the world regardless of race or region. Degenerative discs display a series of characteristic pathological changes, including cell apoptosis, senescence, remodeling of extracellular matrix, oxidative stress and inflammatory local microenvironment. As a serine/threonine-protein kinase in eukaryocytes, AMP-activated protein kinase (AMPK) is involved in various cellular processes through the modulation of cell metabolism and energy balance. Recent studies have shown the abnormal activity of AMPK in degenerative disc cells. Besides, AMPK regulates multiple crucial biological behaviors in IDD. In this review, we summarize the pathophysiologic changes of IDD and activation process of AMPK. We also attempt to generalize the role of AMPK in the pathogenesis of IDD. Moreover, therapies targeting AMPK in alleviating IDD are analyzed, for better insight into the potential of AMPK as a therapeutic target.

A new immunometabolic perspective of intervertebral disc degeneration.

Intervertebral disc (IVD) degeneration is a common finding on spine imaging that increases in prevalence with age. IVD degeneration is a frequent cause of low back pain, which is a leading cause of disability. The process of IVD degeneration consists of gradual structural change accompanied by severe alterations in metabolic homeostasis. IVD degeneration, like osteoarthritis, is a common comorbidity in patients with obesity and type 2 diabetes mellitus, two metabolic syndrome pathological conditions in which adipokines are important promoters of low-grade inflammation, extracellular matrix degradation and fibrosis. Impairment in white adipose tissue function, due to the abnormal fat accumulation in obesity, is characterized by increased production of specific pro-inflammatory proteins such as adipokines by white adipose tissue and of cytokines such as TNF by immune cells of the stromal compartment. Investigations into the immunometabolic alterations in obesity and type 2 diabetes mellitus and their interconnections with IVD degeneration provide insights into how adipokines might affect the pathogenesis of IVD degeneration and impair IVD function and repair. Toll-like receptor-mediated signalling has also been implicated as a promoter of the inflammatory response in the metabolic alterations associated with IVD and is thus thought to have a role in IVD degeneration. Pathological starvation, obesity and adipokine dysregulation can result in immunometabolic alterations, which could be targeted for the development of new therapeutics.

A Study on COMP and CTX-II as Molecular Markers for the Diagnosis of Intervertebral Disc Degeneration.

Background Diagnosis of intervertebral disc degeneration (IVDD) is challenging at the early stage. The cartilage oligomeric matrix protein (COMP) and extracellular matrix degradation products of C-telopeptide of type II collagen (CTX-II) serve as markers for the serological diagnosis of IVDD. Oxidative stress might cause IVDD and matrix degeneration. Methods A total of 128 male adult Sprague–Dawley (SD) rats were randomly and equally assigned to the experimental and control groups. The experimental group was used to construct IVDD models by acupuncture, while the control group underwent sham operation. The animals were executed every week for 8 weeks after intervertebral disc acupuncture, and serum samples were collected for the estimation of CTX-II and COMP concentrations by enzyme-linked immunosorbent assay (ELISA). Also, the histological changes and caudal magnetic resonance imaging (MRI) changes were examined in the intervertebral disc. Results IVDD in rats worsened with prolonged follow-up after acupuncture. At all the time points, the experimental group showed altered histological and caudal vertebra MRI signals, and serum CTX-II and COMP concentrations were significantly greater than those of the control group. These levels increase with the process of IVDD. Conclusion Serum CTX-II and COMP estimation is a reliable method to diagnose IVDD, and their concentrations show a positive correlation with the process of IVDD.

Role of the miR-133a-5p/FBXO6 axis in the regulation of intervertebral disc degeneration.

ObjectiveLow back pain is a leading cause of disabilities worldwide, and intervertebral disc degeneration (IVDD)-related disorders have been recognised as one of the main contributors. Nevertheless, the underlying mechanism has not yet been fully understood. The aim of this study was to investigate the role of the miR-133a-5p/FBXO6 axis in the regulation of IVDD.MethodsRT-qPCR, WB and IHC were performed to assess the expression of FBXO6 in human IVD tissues. Nucleus pulposus (NP) cells were treated with IL-1β to induce IVDD cellular model. Silence of FBXO6 was achieved using specific siRNAs. CCK-8 assay, flow cytometry, TUNEL assay, RT-qPCR and WB were used to evaluate the role and mechanism of FBXO6 in the process of IVDD. Online tools, GSE datasets and RT-qPCR were used to search the candidate miRNAs targeting FBXO6. The direct binding sites between FBXO6 and miR-133a-5p were further verified by a dual luciferase assay. RT-qPCR, WB and rescue experiments were conducted to identify the regulatory function of miR-133a-5p on the expression of aggrecan, collagen Ⅱ, MMP3, ADAMTS5, IL-6 and COX2. In addition, the role of the NF-κB pathway in regulating miR-133a-5p was studied using lentiviral shRNA, WB and RT-qPCR.ResultsResults showed that FBXO6 mainly expressed in the NP tissue of IVD and the expression of FBXO6 decreased with the process of IVDD as well as under IL-1β stimulation. The silence of FBXO6 led to the decreased expression of aggrecan and collagen Ⅱ and the increased expression of MMP3, ADAMTS5, IL-6 and COX2, which further induced the degeneration of NP cells. The bioinformatic analysis showed that miR-133a-5p was the candidate miRNA targeting FBXO6. miR-133a-5p was upregulated in IVDD tissues and significantly inhibited the expression of FBXO6. The inhibition of miR-133a-5p ameliorated the acceleration of IVDD induced by the silence of FBXO6 in vitro. Moreover, it was demonstrated that IL-1β regulated the expression of the miR-133a-5p/FBXO6 axis via the NF-κB pathway in NP cells.ConclusionmiR-133a-5p was upregulated by IL-1β to aggravate intervertebral disc degeneration via sponging FBXO6. Inhibiting miR-133a-5p expression or rescuing FBXO6 expression may be promising strategies for the treatment of IVDD.The translational potential of this articleThis study suggests that the miR-133a-5p/FBXO6 axis could regulate NP cells proliferation, apoptosis, synthesis and degradation of extracellular matrix, which provides a promising therapeutic target and strategy for the treatment of IVDD.

Pharmacological Disruption of Phosphorylated Eukaryotic Initiation Factor-2α/Activating Transcription Factor 4/Indian Hedgehog Protects Intervertebral Disc Degeneration via Reducing the Reactive Oxygen Species and Apoptosis of Nucleus Pulposus Cells.

Excessive reactive oxygen species (ROS) and apoptosis in nucleus pulposus (NP) cells accelerate the process of intervertebral disc degeneration (IDD). Here, we integrated pathological samples and in vitro and in vivo framework to investigate the impact of phosphorylation of eukaryotic initiation factor-2α (eIF2α)/activating transcription factor 4 (ATF4)/Indian hedgehog (Ihh) signaling in the IDD. From the specimen analysis of the IDD patients, we found phosphorylated eIF2α (p-eIF2α), ATF4 and Ihh protein levels were positively related while the NP tissue went degenerative. In vitro, tumor necrosis factor (TNF)-α caused the NP cell degeneration and induced a cascade of upregulation of p-eIF2α, ATF4, and Ihh. Interestingly, ATF4 could enhance Ihh expression through binding its promoter region, and silencing of ATF4 decreased Ihh and protected the NP cells from degeneration. Moreover, ISRIB inhibited the p-eIF2α, which resulted in a suppression of ATF4/Ihh, and alleviated the TNF-α-induced ROS production and apoptosis of NP cells. On the contrary, further activating p-eIF2α aggravated the NP cell degeneration, with amplification of ATF4/Ihh and a higher level of ROS and apoptosis. Additionally, applying cyclopamine (CPE) to suppress Ihh was efficient to prevent NP cell apoptosis but did not decrease the ROS level. In an instability-induced IDD model in mice, ISRIB suppressed p-eIF2α/ATF4/Ihh and prevented IDD via protecting the anti-oxidative enzymes and decreased the NP cell apoptosis. CPE prevented NP cell apoptosis but did not affect anti-oxidative enzyme expression. Taken together, p-eIF2α/ATF4/Ihh signaling involves the ROS level and apoptosis in NP cells, the pharmacological disruption of which may provide promising methods in preventing IDD.

Regeneration in Spinal Disease: Therapeutic Role of Hypoxia-Inducible Factor-1 Alpha in Regeneration of Degenerative Intervertebral Disc.

The intervertebral disc (IVD) is a complex joint structure comprising three primary components—namely, nucleus pulposus (NP), annulus fibrosus (AF), and cartilaginous endplate (CEP). The IVD retrieves oxygen from the surrounding vertebral body through CEP by diffusion and likely generates ATP via anaerobic glycolysis. IVD degeneration is characterized by a cascade of cellular, compositional, structural changes. With advanced age, pronounced changes occur in the composition of the disc extracellular matrix (ECM). NP and AF cells in the IVD possess poor regenerative capacity compared with that of other tissues. Hypoxia-inducible factor (HIF) is a master transcription factor that initiates a coordinated cellular cascade in response to a low oxygen tension environment, including the regulation of numerous enzymes in response to hypoxia. HIF-1α is essential for NP development and homeostasis and is involved in various processes of IVD degeneration process, promotes ECM in NP, maintains the metabolic activities of NP, and regulates dystrophic mineralization of NP, as well as angiogenesis, autophagy, and apoptosis during IVD degeneration. HIF-1α may, therefore, represent a diagnostic tool for early IVD degeneration and a therapeutic target for inhibiting IVD degeneration

Neuropeptide Y prevents nucleus pulposus cells from cell apoptosis and IL‑1β‑induced extracellular matrix degradation

ABSTRACT Intervertebral disc degeneration (IDD) is characterized by excessive inflammatory reaction, and neuropeptide Y (NPY) was reported to have anti-inflammatory effect. However, the effect of NPY on NP cells has not been investigated up to date. This study aimed to clarify the role of NPY on the process of IDD. Fourteen fresh human lumbar intervertebral discs were harvested, and degeneration-related proteins were examined. Pfirrmann grading system was used to evaluate IDD. Rat nucleus pulposus (NP) cells were used to investigate the effect of NPY on the proliferation, apoptosis, and extracellular matrix (ECM) in NP cell induced by IL-1βin vitro. The expression levels of NPY and its receptors (type 1 receptor, Y1R, and type 2 receptor, Y2R) were detected via immunohistochemical analysis, western blot, and quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability and proliferation were explored using cell counting kit-8 assay, western blot, and immunofluorescence analysis. Cell apoptosis was investigated by Hoechst staining, JC-1 Staining, annexin V-FITC/PI double staining, and western blot. The secretion of NPY from NP cells was determined via enzyme-linked immunosorbent assay (ELISA). The expression of anabolic and catabolic gene was analyzed by qRT-PCR, western blot, immunofluorescence analysis, and ELISA. The expression of Y2R was significantly increased in both human degenerative intervertebral discs and IL-1β-induced NP cells. Although no positive results for NPY indicated by western blot both in vivo and in vitro, ELISA results demonstrated that the secretion of NPY from NP cells was increased by low-concentration IL-1β, but was decreased when the concentration of IL-1β was 30 ng/ml and above. In addition, NPY could promote NP cells proliferation and protect NP cells against IL‑1β‑induced apoptosis via suppressing mitochondrial-mediated apoptosis pathway. What’s more, NPY can suppress the expression of catabolic gene and ameliorate IL-1β- induced matrix degeneration in NP cells. In conclusion, NPY could promote NP cell proliferation and alleviate IL‑1β‑induced cell apoptosis via mitochondrial pathway. In addition, NPY can suppress the expression of ECM‑catabolic proteinases and ameliorate IL-1β- induced ECM degeneration in vitro.

MiR-142-3p and HMGB1 Are Negatively Regulated in Proliferation, Apoptosis, Migration, and Autophagy of Cartilage Endplate Cells

Cartilage endplate (CEP) degeneration plays a vital role in the pathological process of intervertebral disc degeneration. It has been previously reported that microRNAs may participate in the occurrence and development of intervertebral disc degeneration through regulating its target genes directly. The regulatory roles of miR-142-3p/HMGB1 in some orthopedic diseases have been determined successively, but there was no report about the degeneration of CEP. Therefore, we aimed to determine the regulation of miR-142-3p/HMGB1 or potential molecular mechanisms on proliferation, apoptosis, migration, and autophagy of CEP cells. The target gene of miR-142-3p was determined by double luciferase assay. We selected ATDC5 cell lines. CCK-8 method was used to detect cell proliferation. Real-time fluorescence quantitative polymerase chain reaction was used to determine gene expression levels, and western blot analysis was used to determine protein expression levels. We chose flow cytometry to measure cell apoptosis and cell cycle. The result of luciferase detection showed that the target gene of miR-142-3p in CEP cells was HMGB1. Knockdown of the miR-142-3p inhibited the expression level of HMGB1, the proliferation and migration of CEP cells, but it promoted apoptosis of CEP cells. In addition, the detection results of the proteins related to apoptosis or autophagy showed that knockdown of miR-142-3p promoted apoptosis and autophagy. The negative regulation of miR-142-3p/HMGB1 can affect the proliferation, apoptosis, migration, and autophagy of CEP cells. Our results provide a new idea for the targeted treatment of CEP degeneration by inhibiting the expression of HMGB1.

The Mechanisms and Functions of GDF-5 in Intervertebral Disc Degeneration.

Intervertebral disc degeneration (IDD) is widely recognized as the main cause of low back pain, which leads to disability in aging populations and induces great losses both socially and economically worldwide. Unfortunately, current treatments for IDD are aimed at relieving symptoms instead of preserving disc structure and function. Researchers are forged to find new promising biological therapeutics to stop, and even reverse, IVD degeneration. Recently, the injection of growth factors has been shown to be a promising biological therapy for IDD. A number of growth factors have been investigated to modulate the synthesis of the extracellular matrix (ECM) through a variety of pathogenetic biological mechanisms, including suppressing inflammatory process and down‐regulating degrading enzymes. However, growth factors, including Transforming Growth Factor‐β (TGF‐β), Fibroblast Growth Factor (FGF), and Insulin‐like Growth Factor‐1 (IGF‐1), may induce unwanted blood vessel in‐growth, which accelerates the process of IDD. On the contrary, studies have demonstrated that injection of GDF‐5 into the intervertebral disc of mice can effectively alleviate the degeneration of the intervertebral disc, which elicits their response via BMPRII and will not induce blood vessel in‐growth. This finding suggests that GDF‐5 is more suitable for use in IDD treatment compared with the three other growth factors. Substantial evidence has suggested that GDF‐5 may maintain the structure and function of the intervertebral disc (IVD). GDF‐5 plays an important role in IDD and is a very promising therapeutic agent for IDD. This review is focused on the mechanisms and functions of GDF‐5 in IDD.

Protective effect of estrogen receptors (ERα/β) against the intervertebral disc degeneration involves activating CCN5 via the promoter.

Due to the decrease of estrogen and estrogen receptor (ER) in postmenopausal women, they have a higher risk of intervertebral disc degeneration (IDD) than men. This study aims to explore how ERα and ERb interact with CCN5 and protect IDD. We used Chromatin immunoprecipitation (ChIP) and Luciferase reporter assay to determine whether the ERα/b protein binds to CCN5 promoter and activates its expression. We used TNF-α to induce nucleus pulposus (NP) cell degeneration to simulate the IDD process. The change of the expression of ERα/β and CCN5 was measured in the degenerated NP cells. To understand the function of ERα/β in the NP cells degeneration, we upregulated the ERα/b gene expression by vector transfection or 17b-estradiol (E2) stimulation. Besides, we also used the CCN5 gene-silenced NP cells by siRNA transfection as a comparison to determine the role of CCN5. We tested the cell proliferation and principal components of the extracellular matrix (ECM) to value the degree of NP cell degeneration. ERα and ERβ protein can bind to the same promoter regions of CCN5 and activate its expression, respectively. TNF-α degraded NP cells with a reduction of cell proliferation, collagen II, ACAN, ERα, ERβ, and CCN5 expression, and increased collagen I/III, and MMP-13 expression. Upregulated ERα or ERβ resulted in the maintains of CCN5 and alleviated the NP cell degeneration. Besides, 17β-E2 supplement increased the ERα, ERβ, and CCN5 expression, as well as stable NP cells phenotype. However, it was partly abolished by the silencing of CCN5. Upregulation of ERα and ERβ protects the NP cell degeneration during IDD through the activation of CCN5 by binding to its promoter.

MiR-874-3p plays a protective role in intervertebral disc degeneration by suppressing MMP2 and MMP3

Intervertebral disc degeneration (IDD) is a spinal degenerative disease and one of the most important causes of musculoskeletal disability. Matrix metalloproteinase (MMP)-mediated extracellular matrix degradation is the core process of IDD. The regulators of MMPs in the intervertebral disc are still not fully known. In this study, using quantitative reverse transcription PCR, luciferase reporter assay, Western blotting, immunofluorescence, flow cytometry, and Cell Counting Kit-8 assay, we found that the miR-874-3p expression level was significantly decreased in IDD patients. MiR-874-3p could target and repress MMP2 and MMP3 expression in nucleus pulposus cells. These results could improve the understanding of IDD and provide a possible diagnostic marker and treatment candidate for IDD. The miR-874-3p/MMP2/MMP3 axis might also provide direction for future cancer and inflammation investigations.

Glycine-Serine-Threonine Metabolic Axis Delays Intervertebral Disc Degeneration through Antioxidant Effects: An Imaging and Metabonomics Study.

Although intervertebral disc degeneration (IDD) can be described as different stages of change through biological methods, this long and complex process cannot be defined in stages by single or simple combination of biological techniques. Under the background of the development of nuclear magnetic resonance (NMR) technology and the emerging metabonomics, we based on animal models and expanded to the study of clinical human degeneration models. The characteristics of different stages of IDD were analyzed by omics. Omics imaging combined with histology, cytology, and proteomics was used for screening of the intervertebral disc (IVD) of research subjects. Furthermore, mass spectrometry nontargeted metabolomics was used to explore profile of metabolites at different stages of the IDD process, to determine differential metabolic pathways and metabolites. NMR spectroscopy was used to qualitatively and quantitatively identify markers of degeneration. NMR was combined with mass spectrometry metabolomics to explore metabolic pathways. Metabolic pathways were determined through protein molecular biology and histocytology of the different groups. Distinguishing advantages of magnetic resonance spectroscopy (MRS) for analysis of metabolites and effective reflection of structural integrity and water molecule metabolism through diffusion tensor imaging (DTI) were further used to verify the macrometabolism profile during degeneration. A corresponding model of in vitro metabolomics and in vivo omics imaging was established. The findings of this study show that a series of metabolic pathways associated with the glycine-serine-threonine (Gly-Ser-Thr) metabolic axis affects carbohydrate patterns and energy utilization efficiency and ultimately delays disc degeneration through antioxidant effects.

The Regulatory Effect of MicroRNA-101-3p on Disc Degeneration by the STC1/VEGF/MAPK Pathway.

Aims. Accumulating evidence reported that the microRNA (miRNA) took an important role in intervertebral disc degeneration (IDD). In this study, we revealed a novel miRNA regulatory mechanism in IDD. Main Methods. The miRNA microarray analyses of human degenerated and normal disc samples were employed to screen out the target miRNA. In vitro and in vivo experiments were conducted to verify the regulatory effect of miR-101-3p. Key Findings. The expression level of miR-101-3p was significantly decreased in the degenerated disc samples which were confirmed by qRT-PCR. Moreover, the miR-101-3p expression level was changed dynamically according to the disc degeneration grade. Upregulation of miR-101-3p expression level inhibited cell apoptosis. Furthermore, stanniocalcin-1 (STC1) was selected to be the target gene of miR-101-3p according to the bioinformatic algorithms. Mechanically, upregulation of miR-101-3p significantly decreased the expression of STC1, vascular endothelial growth factor (VEGF), and MAPK pathway expression levels. Therapeutically, in vivo experiment on IDD rat model illustrated that agomir-101-3p could effectively suspend IDD. Significance. Our findings demonstrated that miR-101-3p alleviated IDD process through the STC1/VEGF/MAPK pathway.

Cartilage intermediate layer protein affects the progression of intervertebral disc degeneration by regulating the extracellular microenvironment (Review).

Intervertebral disc degeneration (IDD), which is caused by multiple factors, affects the health of individuals and contributes to low back pain. The pathology of IDD is complicated, and changes in the extracellular microenvironment play an important role in promoting the process of degeneration. Cartilage intermediate layer protein (CILP) is a matrix protein that resides in the middle of human articular cartilage and is involved in numerous diseases that affect cartilage. However, there is no detailed review of the relationship between CILP and degenerative disc disease. Growing evidence has revealed the presence of CILP in the extracellular microenvironment of intervertebral discs (IVDs) and has suggested that there is a gradual increase in CILP in degenerative discs. Specifically, CILP plays an important role in regulating the metabolism of the extracellular matrix (ECM), an important component of the extracellular microenvironment. CILP can combine with transforming growth factor-β or insulin-like growth factor-1 to regulate the ECM synthesis of IVDs and influence the balance of ECM metabolism, which leads to changes in the extracellular microenvironment to promote the process of IDD. It may be possible to show the correlation of CILP with IDD and to target CILP to interfere with IDD. For this purpose, in the present study, the current knowledge on CILP was summarized and a detailed description of CILP in discs was provided.

Advanced Glycation End Product Inhibitor Pyridoxamine Attenuates IVD Degeneration in Type 2 Diabetic Rats.

Type 2 diabetes mellitus (T2DM) is associated with advanced glycation end product (AGE) enrichment and considered a risk factor for intervertebral disc (IVD) degeneration. We hypothesized that systemic AGE inhibition, achieved using pyridoxamine (PM), attenuates IVD degeneration in T2DM rats. To induce IVD degeneration, lumbar disc injury or sham surgery was performed on Zucker Diabetic Sprague Dawley (ZDSD) or control Sprague Dawley (SD) rats. Post-surgery, IVD-injured ZDSD rats received daily PM dissolved in drinking water or water only. The resulting groups were SD uninjured, SD injured, ZDSD uninjured, ZDSD injured, and ZDSD injured + PM. Levels of blood glycation and disc degeneration were investigated. At week 8 post-surgery, glycated serum protein (GSP) levels were increased in ZDSDs compared to SDs. PM treatment attenuated this increase. Micro-MRI analysis demonstrated IVD dehydration in injured versus uninjured SDs and ZDSDs. In the ZDSD injured + PM group, IVD dehydration was diminished compared to ZDSD injured. AGE levels were decreased and aggrecan levels increased in ZDSD injured + PM versus ZDSD injured rats. Histological and immunohistochemical analyses further supported the beneficial effect of PM. In summary, PM attenuated GSP levels and IVD degeneration processes in ZDSD rats, demonstrating its potential to attenuate IVD degeneration in addition to managing glycemia in T2DM.

Senolytic agent Quercetin ameliorates intervertebral disc degeneration via the Nrf2/NF-κB axis

Intervertebral disc degeneration (IDD) represents major cause of low back pain. Quercetin (QUE) is one of the approved senolytic agents. In this study, we evaluated the protective effects of QUE on IDD development and its underlying mechanism. Effects of senolytic agent QUE on the viability of nucleus pulposus cells (NPCs) were measured by CCK-8 assays and EdU staining. The senescence associated secreted phenotype (SASP) factors expressions were measured by qPCR, western blot, and ELISA; and NF-κB pathway was detected by immunofluorescence and western blot. Molecular docking was applied to predict the interacting protein of QUE; while Nrf2 was knocked down by siRNAs to confirm its role in QUE regulated senescence phenotype. X-ray, MRI, Hematoxylin-Eosin and Safranin O-Fast green staining were performed to evaluate the therapeutic effects of QUE on IDD in the puncture-induced rat model. In in vitro experiments, QUE inhibited SASP factors expression and senescence phenotype in IL-1β-treated NPCs. Mechanistically, QUE suppressed IL-1β induced activation of the NF-κB pathway cascades; it was also demonstrated in molecular docking and knock down studies that QUE might bind to Keap1-Nrf2 complex to suppress NF-κB pathway. In vivo, QUE ameliorated the IDD process in the puncture-induced rat model. Together the present work suggests that QUE inhibits SASP factors expression and senescence phenotype in NPCs and ameliorates the progression of IDD via the Nrf2/NF-κB axis, which supports senolytic agent QUE as a potential therapeutic agent for the treatment of IDD.