The PI3K/Akt pathway: a critical player in intervertebral disc degeneration

Dynamics of CD44+ bovine nucleus pulposus cells with inflammation

Intervertebral Disc (IVD) degeneration has been associated with a chronic inflammatory response, but knowledge on the contribution of distinct IVD cells, namely CD44, to the progression of IVD degeneration remains elusive. Here, bovine nucleus pulposus (NP) CD44 cells were sorted and compared by gene expression and proteomics with the negative counterpart. NP cells were then stimulated with IL-1b (10 ng/ml) and dynamics of CD44 gene and protein expression was analyzed upon pro-inflammatory treatment. The results emphasize that CD44 has a multidimensional functional role in IVD metabolism, ECM synthesis and production of neuropermissive factors. CD44 widespread expression in NP was partially associated with CD14 and CD45, resulting in the identification of distinct cell subsets. In conclusion, this study points out CD44 and CD44-based cell subsets as relevant targets in the modulation of the IVD pro-inflammatory/degenerative cascade.

Stress-Activated Protein Kinases in Intervertebral Disc Degeneration: Unraveling the Impact of JNK and p38 MAPK

Intervertebral disc degeneration (IDD) is a major cause of lower back pain. The pathophysiological development of IDD is closely related to the stimulation of various stressors, including proinflammatory cytokines, abnormal mechanical stress, oxidative stress, metabolic abnormalities, and DNA damage, among others. These factors prevent normal intervertebral disc (IVD) development, reduce the number of IVD cells, and induce senescence and apoptosis. Stress-activated protein kinases (SAPKs), particularly, c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK), control cell signaling in response to cellular stress. Previous studies have shown that these proteins are highly expressed in degenerated IVD tissues and are involved in complex biological signal-regulated processes. Therefore, we summarize the research reports on IDD related to JNK and p38 MAPK. Their structure, function, and signal regulation mechanisms are comprehensively and systematically described and potential therapeutic targets are proposed. This work could provide a reference for future research and help improve molecular therapeutic strategies for IDD.

ANGPTL4 May Regulate the Crosstalk Between Intervertebral Disc Degeneration and Type 2 Diabetes Mellitus: A Combined Analysis of Bioinformatics and Rat Models

Introduction

The crosstalk between intervertebral disc degeneration (IVDD) and type 2 diabetes mellitus (T2DM) has been investigated. However, the common mechanism underlying this phenomenon has not been clearly elucidated. This study aimed to explore the shared gene signatures of IVDD and T2DM.

Methods

The expression profiles of IVDD (GSE27494) and T2DM (GSE20966) were acquired from the Gene Expression Omnibus database. Five hub genes including ANGPTL4, CCL2, CCN3, THBS2, and INHBA were preliminarily screened. GO (Gene Ontology) enrichment analysis, functional correlation analysis, immune filtration, Transcription factors (TFs)-mRNA-miRNA coregulatory network, and potential drugs prediction were performed following the identification of hub genes. RNA sequencing, in vivo and in vitro experiments on rats were further performed to validate the expression and function of the target gene.

Results

Five hub genes (ANGPTL4, CCL2, CCN3, THBS2, and INHBA) were identified. GO analysis demonstrated the regulation of the immune system, extracellular matrix (ECM), and SMAD protein signal transduction. There was a strong correlation between hub genes and different functions, including lipid metabolism, mitochondrial function, and ECM degradation. The immune filtration pattern grouped by disease and the expression of hub genes showed significant changes in the immune cell composition. TFs-mRNA-miRNA co-expression networks were constructed. In addition, pepstatin showed great drug-targeting relevance based on potential drugs prediction of hub genes. ANGPTL4, a gene that mediates the inhibition of lipoprotein lipase activity, was eventually determined after hub gene screening, validation by different datasets, RNA sequencing, and experiments.

Discussion

This study screened five hub genes and ANGPTL4 was eventually determined as a potential target for the regulation of the crosstalk in patients with IVDD and T2DM.

Astragaloside IV relieves IL-1β-induced human nucleus pulposus cells degeneration through modulating PI3K/Akt signaling pathway

BACKGROUND

Intervertebral disc degeneration (IDD) is a multifactorial disease that is associated with nucleus pulposus (NP) apoptosis and extracellular matrix (ECM) degeneration and inflammation. Astragaloside IV (AS IV) has antioxidant, free radical scavenging, anti-inflammatory and anti-apoptosis effects. This study was to investigate whether AS IV could inhibit IL-1β-mediated apoptosis of HNP cells and its possible signal transduction pathway.

METHODS

Human nucleus pulposus cells (HNPCs) were stimulated with AS IV or LY294002 (PI3K inhibitor), followed by exposure to IL-1β for 24 hours. CCK8, TUNEL analysis and flow cytometry, ELISA and Western blotting were used to analyze the effects of AS IV on cell proliferation, apoptosis, inflammation, ECM and PI3K/Akt pathway signaling path-related proteins in IL-1β-induced HNPCs.

RESULTS

Compared with IL-1β-induced HNPCs, AS IV could improve the proliferation activity and the expressions of Collagen II, Aggrecan and Bcl-2 proteins, inhibit the apoptosis rate, inflammation and Bax and cleaved caspase-3 protein expression, and increase the activity of PI3K/Akt pathway. LY294002 attenuated the protective effect of AS IV against IL-1β-induced HNPCs degeneration.

CONCLUSION

AS IV can inhibit IL-1β-induced HNPCs apoptosis inflammation and ECM degeneration by activating PI3K/Akt signaling pathway, which can be an effective drug to reduce disc degeneration.

Identification of novel gene signatures and immune cell infiltration in intervertebral disc degeneration using bioinformatics analysis

Background: Intervertebral disc degeneration (IDD) is the leading cause of lower back pain, and an overall understanding of the molecular mechanisms related to IDD is still lacking. The purpose of this study was to explore gene signatures and immune cell infiltration related to IDD via bioinformatics analysis. Methods: A total of five expression profiles of mRNA and non-coding RNA were downloaded from the Gene Expression Omnibus (GEO) database. The potentially involved lncRNA/circRNA-miRNA-mRNA networks and protein-protein interaction networks were constructed by miRNet, circBank, STRING, and the Cytoscape database. Gene ontology, Kyoto Encyclopaedia of Genes and Genomes Analysis, Gene Set Enrichment Analysis, Gene Set Variation Analysis, Immune Infiltration Analysis, and Drug-Gene Interaction were used to analyse the top 20 hub genes. RT-qPCR was conducted to confirm the 12 differential expressions of genes both in the nucleus pulposus and annulus fibrosus tissues Results: There were 346 differentially expressed mRNAs, 12 differentially expressed miRNAs, 883 differentially expressed lncRNAs, and 916 differentially expressed circRNAs in the GEO database. Functional and enrichment analyses revealed hub genes associated with platelet activation, immune responses, focal adhesion, and PI3K-Akt signalling. The apoptotic pathway, the reactive oxygen species pathway, and oxidative phosphorylation play an essential role in IDD. Immune infiltration analysis demonstrated that the Treg cells had significant infiltration, and three levels of immune cells, including dendritic cells, Th2 cells, and tumour-infiltrating lymphocytes, were inhibited in IDD. Drug-gene interaction analysis showed that COL1A1 and COL1A2 were targeted by collagenase clostridium histolyticum, ocriplasmin, and PDGFRA was targeted by 66 drugs or molecular compounds. Finally, 24 cases of IDD tissues and 12 cases of normal disc tissues were collected, and the results of RT-qPCR were consistent with the bioinformatics results. Conclusion: Our data indicated that the 20 hub genes and immune cell infiltration were involved in the pathological process of IDD. In addition, the PDGFRA and two potential drugs were found to be significant in IDD development.

A Study Based on Network Pharmacology Decoding the Multi-Target Mechanism of Duhuo Jisheng Decoction for the Treatment of Intervertebral Disc Degeneration

Intervertebral disc degeneration (IDD) poses a grim public health impact. Duhuo Jisheng Decoction (DJD), a traditional Chinese medicine formula, has recently received significant attention for its efficacy and safety in treating IDD. However, the pathological processes of IDD in which DJD interferes and molecular mechanism involved are poorly understood, which brings difficulties to the clinical practice of DJD for the treatment of IDD. This study systematically investigated the underlying mechanism of DJD treatment of IDD. Network pharmacology approaches were employed, integrating molecular docking and random walk with restart (RWR) algorithm, to identify key compounds and targets for DJD in the treatment of IDD. Bioinformatics approaches were used to further explore the biological insights in DJD treatment of IDD. The analysis identifies AKT1, PIK3R1, CHUK, ALB, TP53, MYC, NR3C1, IL1B, ERBB2, CAV1, CTNNB1, AR, IGF2, and ESR1 as key targets. Responses to mechanical stress, oxidative stress, cellular inflammatory responses, autophagy, and apoptosis are identified as the critical biological processes involved in DJD treatment of IDD. The regulation of DJD targets in extracellular matrix components, ion channel regulation, transcriptional regulation, synthesis and metabolic regulation of reactive oxygen products in the respiratory chain and mitochondria, fatty acid oxidation, the metabolism of Arachidonic acid, and regulation of Rho and Ras protein activation are found to be potential mechanisms in disc tissue response to mechanical stress and oxidative stress. MAPK, PI3K/AKT, and NF-κB signaling pathways are identified as vital signaling pathways for DJD to treat IDD. Quercetin and Kaempferol are assigned a central position in the treatment of IDD. This study contributes to a more comprehensive understanding of the mechanism of DJD in treating IDD. It provides a reference for applying natural products to delay the pathological process of IDD.

Danggui Shaoyaosan attenuates doxorubicin induced Nephrotic Syndrome through regulating on PI3K/Akt Pathway

The study aimed to explore the role and the underlying mechanism of Danggui Shaoyaosan (DSS) in nephrotic syndrome (NS). NS rat model was induced by doxorubicin injection twice. After DSS treatment, inflammation and oxidative stress index were detected via ELISA. Western blot was used for the protein detection. Go and KEGG analysis was applied to evaluate target gene and signaling of DSS. MCP-5 cell was applied for the cell rescue experiments and mechanism exploration. The 24 h urine protein levels of NS rats increased significantly, which was reduced by DSS treatment in a concentration-dependent manner. After DSS treatment, levels of BUN, SCr, TG and TC were also decreased, and serum ALB and TP levels were increased in rats. GO and KEGG pathway enrichment identified PI3K-Akt to be the candidate signaling of DSS in the treatment of NS, which was activated in NS rats. The recuse experiments in MCP-5 demonstrated that IGF-1, the agonist of PI3K/AKT, abolished the beneficial role of DSS in podocyte cell viability, apoptosis, inflammation and oxidative stress. In conclusion, DSS exerts a protective role against the development of NS. The mechanism is related to the improvement of podocyte injury and the inhibition of PI3K/Akt pathway-related proteins.

Embelin protects against apoptosis and inflammation by regulating PI3K/Akt signaling in IL-1β-stimulated human nucleus pulposus cells

Embelin is a natural benzoquinone compound that displays a beneficial effect in various inflammatory-related diseases. However, the effect of embelin on degeneration of intervertebral disc (IDD), a chronic inflammatory disorder, has not been reported. This study was attempted to explore the therapeutic action of embelin on IDD in vitro. Network pharmacology analysis was performed for evaluating the link between embelin and IDD. The human nucleus pulposus cells (NPCs) were stimulated with IL-1β to induce inflammation. Cell viability of NPCs was assessed by CCK-8 assay. Western blotting was conducted to detect the expression levels of PI3K, p-PI3K, Akt, p-Akt, cleaved caspase-3, caspase-3, Bax, Bcl-2, p65 and p-p65. Apoptotic deaths of NPCs were examined by TUNEL assay. The production of COX-2, IL-6, IL-8, and TNF-α was examined by ELISA. It can be seen that 16 overlapping genes were selected from 109 possible targets of embelin and 342 possible targets of IDD. KEGG pathway enrichment analysis showed that the PI3K/Akt signaling pathway was a close link between embelin and IDD. We found that embelin dose-dependently improved the cell viability in IL-1β-stimulated NPCs. Embelin elevated the relative levels of p-PI3K/PI3K and p-Akt/Akt in IL-1β-stimulated NPCs. IL-1β induced a significant increase in apoptotic deaths of NPCs, which was attenuated by embelin treatment. IL-1β-induced alternations in expression levels of apoptotic-related proteins including cleaved caspase-3, Bax and Bcl-2 were prevented by embelin treatment. Pretreatment with LY294002 (an inhibitor of PI3K) reversed the inhibitory effect of embelin on IL-1β-induced apoptosis in NPCs. Embelin treatment caused inhibitory effects on the IL-1β-stimulated production of COX-2, IL-6, IL-8, and TNF-α, which were abolished by LY294002 treatment. Furthermore, embelin treatment prevented IL-1β-induced phosphorylation of p65 in NPCs, while LY294002 elevated the embelin-caused decrease in p-p65/p65 level. Overall, embelin protected human NPCs against IL-1β-stimulated apoptosis and inflammation by regulating the PI3K/Akt signaling pathway. These findings provided new ideas for the clinical usage of embelin in the prevention and treatment of IDD.

Investigating regulated signaling pathways in therapeutic targeting of non-small cell lung carcinoma

Non-small cell lung carcinoma (NSCLC) is the most common malignancy worldwide. The signaling cascades are stimulated via genetic modifications in upstream signaling molecules, which affect apoptotic, proliferative, and differentiation pathways. Dysregulation of these signaling cascades causes cancer-initiating cell proliferation, cancer development, and drug resistance. Numerous efforts in the treatment of NSCLC have been undertaken in the past few decades, enhancing our understanding of the mechanisms of cancer development and moving forward to develop effective therapeutic approaches. Modifications of transcription factors and connected pathways are utilized to develop new treatment options for NSCLC. Developing designed inhibitors targeting specific cellular signaling pathways in tumor progression has been recommended for the therapeutic management of NSCLC. This comprehensive review provided deeper mechanistic insights into the molecular mechanism of action of various signaling molecules and their targeting in the clinical management of NSCLC.

Intervertebral disc cell fate during aging and degeneration: apoptosis, senescence, and autophagy

Background

Degenerative disc disease, a major cause of low back pain and associated neurological symptoms, is a global health problem with the high morbidity, workforce loss, and socioeconomic burden. The present surgical strategy of disc resection and/or spinal fusion results in the functional loss of load, shock absorption, and movement; therefore, the development of new biological therapies is demanded. This achievement requires the understanding of intervertebral disc cell fate during aging and degeneration.

Methods

Literature review was performed to clarify the current concepts and future perspectives of disc cell fate, focused on apoptosis, senescence, and autophagy.

Results

The intervertebral disc has a complex structure with the nucleus pulposus (NP), annulus fibrosus (AF), and cartilage endplates. While the AF arises from the mesenchyme, the NP originates from the notochord. Human disc NP notochordal phenotype disappears in adolescence, accompanied with cell death induction and chondrocyte proliferation. Discs morphologically and biochemically degenerate from early childhood as well, thereby suggesting a possible involvement of cell fate including age-related phenotypic changes in the disease process. As the disc is the largest avascular organ in the body, nutrient deprivation is a suspected contributor to degeneration. During aging and degeneration, disc cells undergo senescence, irreversible growth arrest, producing proinflammatory cytokines and matrix-degradative enzymes. Excessive stress ultimately leads to programmed cell death including apoptosis, necroptosis, pyroptosis, and ferroptosis. Autophagy, the intracellular degradation and recycling system, plays a role in maintaining cell homeostasis. While the incidence of apoptosis and senescence increases with age and degeneration severity, autophagy can be activated earlier, in response to limited nutrition and inflammation, but impaired in aged, degenerated discs. The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) is a signal integrator to determine disc cell fate.

Conclusions

Cell fate and microenvironmental regulation by modulating PI3K/Akt/mTOR signaling is a potential biological treatment for degenerative disc disease.

Pharmacological network analysis of the functions and mechanism of kaempferol from Du Zhong in intervertebral disc degeneration (IDD)

Background

Senescence and apoptosis of the nucleus pulposus cells (NPCs) are essential components of the intervertebral disc degeneration (IDD) process. Senescence and anti-apoptosis treatments could be effective ways to delay or even stop disc degeneration. IDD has been treated with Eucommia ulmoides Oliver (Du Zhong, DZ) and its active ingredients. However, the roles and mechanisms of DZ in NPC apoptosis and senescence remain unclear.

Methods

Traditional Chinese Medicine Systems Pharmacology (TCMSP) database was used to select the main active ingredients of DZ with the threshold of oral bioavailability (OB) ​≥ ​30% and drug-likeness (DL) ​≥ ​0.2. GSE34095 contained expression profile of degenerative intervertebral disc tissues and non-degenerative intervertebral disc tissues were downloaded for different expression genes analysis. The disease targets genes of IDD were retrieved from GeneCards. The online tool Metascape was used for functional enrichment annotation analysis. The specific effects of the ingredient on IL-1β treated NPC cell proliferation, cell senescence, reactive oxygen species (ROS) accumulation and cell apoptosis were determined by CCK-8, SA-β-gal staining, flowcytometry and western blot assays.

Results

A total of 8 active compounds of DZ were found to meet the threshold of OB ​≥ ​30% and DL ​≥ ​0.2 with 4151 drug targets. After the intersection of 879 IDD disease targets obtained from GeneCards and 230 DEGs obtained from the IDD-related GSE dataset, a total of 13 hub genes overlapped. According to functional enrichment annotation analysis by Metascape, these genes showed to be dramatically enriched in AGE-RAGE signaling, proteoglycans in cancer, wound healing, transmembrane receptor protein tyrosine kinase signaling, MAPK cascades, ERK1/2 cascades, PI3K/Akt signaling pathway, skeletal system, etc. Disease association analysis by DisGeNET indicated that these genes were significantly associated with IDD, intervertebral disc disease, skeletal dysplasia, and other diseases. Active ingredients-targets-signaling pathway networks were constructed by Cytoscape, and kaempferol was identified as the hub active compound of DZ. In the IL-1β-induced IDD in vitro model, kaempferol treatment significantly improved IL-1β-induced NPC cell viability suppression and senescence. In addition, kaempferol treatment significantly attenuated IL-1β-induced ROS accumulation and apoptosis. Furthermore, kaempferol treatment partially eliminated IL-1β-induced decreases in aggrecan, collagen II, SOX9, and FN1 levels and increases in MMP3, MMP13, ADAMTS-4, and ADAMTS-5. Moreover, kaempferol treatment significantly relieved the promotive effects of IL-1β stimulation upon p38, JNK, and ERK1/2 phosphorylation. ERK1/2 inhibitor PD0325901 further enhanced the effect of kaempferol on the inhibition of ERK1/2 phosphorylation, downregulation of MMP3 and ADAMTS-4 expression, and upregulation of aggrecan and collagen II expressions.

Conclusion

Kaempferol has been regarded as the major active compound of DZ, protecting NPCs from IL-1β-induced damages through promoting cell viability, inhibiting cell senescence and apoptosis, increasing ECM production, and decreasing ECM degradation. MAPK signaling pathway may be involved.

The translational poteintial of this article

This study provides in vitro experimental data support for the pharmacological effects of kaempferol in treating IDD, and lays a solid experimental foundation for its future clinical application in IDD treatment.

Adenosine A1 receptor agonist, N6-cyclohexyladenosine, attenuates Huntington's disease via stimulation of TrKB/PI3K/Akt/CREB/BDNF pathway in 3-nitropropionic acid rat model

Huntington's disease (HD) is an inherited neurodegenerative disease characterized by progressive motor, behavioral, and cognitive impairments. Intrastriatal injection of 3- nitropropionic acid (3NP) was used to induce HD-like symptoms by inhibiting succinate dehydrogenase enzyme (SDH) in the mitochondrial complex II. The adenosine A₁ receptor has long been known to have a crucial role in neuroprotection, mainly by blocking Ca²⁺ influx, which causes inhibition of glutamate (Glu) and a decline in its excitatory effects at the postsynaptic level. To this end, this study investigated the possible involvement of TrKB/PI3K/Akt/CREB/BDNF pathway in mediating protection afforded by the central N6-cyclohexyladenosine (CHA), an adenosine A₁ receptor agonist. A single intrastriatal CHA injection (6.25 nM/1 μL); 45min after 3-NP injection, attenuated neuronal death, and improved cognitive and motor deficits caused by 3-NP neurotoxin. This effect was shown to parallel an enhanced activation of PI3K/Akt/CREB/BDNF axis as well as boosting pERK_1/2 levels. Moreover, CHA attenuated neuroinflammatory and oxidative stress status via reducing NFκB p65, TNFα and iNOS contents and increasing SOD. Furthermore, immunohistochemical data showed a reduction in the glial fibrillary acidic protein (GFAP) immunoreactivity to a marker for astrocyte and microglia activation following CHA treatment. The results of this study suggest that CHA may have protective effect against HD via modulating oxidative stress, excitotoxic and inflammatory pathways.

A microarray data analysis investigating the pathogenesis and potential biomarkers of autophagy and ferroptosis in intervertebral disc degeneration

Background: Intervertebral disc degeneration (IDD) entails complex pathological changes and causes lower back pain (LBP). However, there is still a lack of understanding of the mechanisms involved in IDD, particularly regarding the roles of autophagy and ferroptosis. The current study used microarray data to investigate the pathogenesis of IDD and potential biomarkers related to autophagy and ferroptosis in IDD. Methods: Differentially expressed genes (DEGs) were identified by analyzing the mRNA and miRNA expression profiles of IDD patients from the Gene Expression Omnibus (GEO). The protein-protein interaction network, Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and gene set enrichment analysis (GSEA) were utilized. The Human Autophagy Database (HADb) and Ferroptosis Database were used in conjunction with hub genes to identify autophagy- and ferroptosis-related genes. The Transcription Factor -hub gene-miRNA network was constructed. Lastly, the expression of DEGs in normal and degenerated nucleus pulposus cells (NPCs) was investigated via the quantitative reverse transcription polymerase chain reaction (qRT-PCR). Results: A total of 362 DEGs associated with IDD were identified. GO and KEGG analyses indicated that oxidative stress, extracellular matrix, PI3K-AKT signaling pathway, and ferroptosis were key factors in IDD occurrence. GSEA indicated that IDD was associated with changes in autophagy, iron ion homeostasis, extracellular matrix, and oxidative stress. Eighty-nine hub genes were obtained, including five that were autophagy-related and three that were ferroptosis-related. Of these, TP53 and SESN2 were the intersections of autophagy- and ferroptosis-related genes. In qRT-PCR analysis, CANX, SLC38A1, and TP53 were downregulated in degenerative NPCs, whereas GNAI3, SESN2, and VAMP3 were upregulated. Conclusion: The current study revealed aspects of autophagy- and ferroptosis-related genes involved in IDD pathogenesis, warranting further investigation.

Regulatory Effect of Inflammatory Mediators in Intervertebral Disc Degeneration

Intervertebral disc degeneration (IDD) is a major contributor to back, neck, and radicular pain. It is related to changes in tissue structure and function, including the breakdown of the extracellular matrix (ECM), aging, apoptosis of the nucleus pulposus, and biomechanical tissue impairment. Recently, an increasing number of studies have demonstrated that inflammatory mediators play a crucial role in IDD, and they are being explored as potential treatment targets for IDD and associated disorders. For example, interleukins (IL), tumour necrosis factor-α (TNF-α), chemokines, and inflammasomes have all been linked to the pathophysiology of IDD. These inflammatory mediators are found in high concentrations in intervertebral disc (IVD) tissues and cells and are associated with the severity of LBP and IDD. It is feasible to reduce the production of these proinflammatory mediators and develop a novel therapy for IDD, which will be a hotspot of future research. In this review, the effects of inflammatory mediators in IDD were described.

Genome-wide DNA methylation study identifies significant epigenomic changes associated with internalized stigma in adults with non-specific chronic low back pain

Non-specific chronic low back pain (cLBP) represents a common musculoskeletal condition with no identifiable cause. It cannot be diagnosed with conventional neuroimaging techniques such as computerized tomography (CT). The diagnostic uncertainty that characterizes non-specific cLBP can lead to stigmatizing responses from others that can become internalized Among individuals with non-specific cLBP, internalized stigma is associated with greater pain intensity and disability. Yet, no study has examined the biological mechanism linking high internalized stigma to worse outcomes in individuals with non-specific cLBP. We aimed to identify differentially methylated loci (DML), enrichment pathways, and associated network interactions among individuals with non-specific cLBP experiencing low vs. high internalized stigma. We examined DNA methylation in whole blood samples from 48 adults, ages 19-85, using reduced representation bisulfite sequencing (RRBS). After controlling for age, sex, race, and multiple testing, differentially methylated loci (DML) differed in adults with low vs. high internalized stigma by at least 10% and q < 0.01 in 3,665 CpG sites: 2,280 hypomethylated and 1,385 hypermethylated. Gene ontology (GO) analyses of the annotated genes from these sites revealed significant enrichment of 274 biological processes, 29 cellular components, and 24 molecular functions (adjusted p < 0.05). The top enriched molecular functions regulate protein binding and DNA binding of transcription factor activity. Pathway analyses indicated that many functional genomic pathways, including Hippo Signaling, Melanogenesis, and Pathways in Cancer, were enriched with differentially methylated genes. Also, there was a significant interaction between relevance pathways such as P53, mTOR, PI3K-Akt, and Wnt signaling pathways. These pathways have previously been associated with neuroinflammation, neurodegeneration, and stress-related conditions. Thus, findings point to possible stress-induced DNAm changes as the link between high levels of internalized stigma and worse outcomes in adults with non-specific cLBP.

Achyranthoside D (AD) improve intervertebral disc degeneration through affect the autophagy and the activation of PI3K/Akt/mTOR pathway

PURPOSE

This study aims to explore the potential mechanism of Achyranthoside D (AD) in improving intervertebral disc (IVD) degeneration (IDD).

METHODS

The IDD model of SD rats and nucleus pulposus cells (NPCs) was established by lumbar cone annulus puncture and tert-butyl peroxide, respectively. Cell proliferation was detected by CCK8 assay. Apoptosis was detected by flow cytometry and TUNEL staining. IVD tissue injury was observed by HE staining. Alcian blue staining observed the glycoprotein secretion in IVD. Monodansylcadaverin (MDC) staining was used to detect the formation of autophagosomes. The LC3 expression was tested by immunofluorescence. The type II collagen, aggrecan and MMP3 expression were detected by ELISA. RT-qPCR was used to detect the Casp 3, Bax, Bcl2, Acan, Col2a1 and Mmp3 expression. The LC3, P62, type II collagen, aggrecan, Beclin1, Akt, MMP3, p-mTOR, PI3K, mTOR, p-PI3K and p-Akt expression were analyzed by western blot.

RESULTS

The IVD tissue damage and apoptosis occurred in the Model group, and the glycoprotein secretion decreased. Compared with Model group, AD-H group alleviated the injury of IVD tissue, inhibited the apoptosis of cells, and increased the secretion of glycoprotein. 40 μg/mL AD restored the proliferation activity of NPCs. Compared to the Normal group, the NPCs apoptosis increased, the Collagen II, aggrecan and Bcl2 expressions were significantly decreased, the MMP3, Bax and Casp 3 expression were significantly increased, and the LC-3 II/I expression in IVD tissues were increased significantly in Model group, all of which was reversed in AD group. AD promoted the p-Akt, p-PI3K, p-mTOR, LC-3 II/I and Beclin1 expression, inhibited the P62 expression to alleviate the damage of nucleus pulporeus cells and the degeneration of IVD.

CONCLUSION

AD improved IDD by affecting the PI3K/Akt/mTOR pathway and autophagy.

Proanthocyanidins inhibit the apoptosis and aging of nucleus pulposus cells through the PI3K/Akt pathway delaying intervertebral disc degeneration

BACKGROUND

Low back pain is a common symptom of intervertebral disc degeneration (IDD), which seriously affects the quality of life of patients. The abnormal apoptosis and senescence of nucleus pulposus (NP) cells play important roles in the pathogenesis of IDD. Proanthocyanidins (PACs) are polyphenolic compounds with anti-apoptosis and anti-aging effects. However, their functions in NP cells are not yet clear. Therefore, this study was performed to explore the effects of PACs on NP cell apoptosis and aging and the underlying mechanisms of action.

METHODS

Cell viability was evaluated by cell counting kit-8 (CCK-8) assay. The apoptosis rate was determined TUNEL assays. Levels of apoptosis-associated molecules (Bcl-2, Bax, C-caspase-3 and Caspase-9) were evaluated via western blot. The senescence was observed through SA-β-gal staining and western blotting analysis was performed to observe the expression of senescence-related molecules (p-P53, P53, P21 and P16).

RESULTS

Pretreatment with PACs exhibited protective effects against IL-1β-induced NP cell apoptosis including apoptosis rate, expressions of proapoptosis and antiapoptosis related genes and protein. PACs could also alleviate the increase of p-p53, P21, and P16 in IL-1β-treated NP cells. SA-β-gal staining showed that IL-1β-induced senescence of NP cells was prevented by PACs pertreatment. In addition, PACs activated PI3K/Akt pathway in IL-1β-stimulated NP cells. However, these protected effects were inhibited after LY294002 treatment.

CONCLUSION

The results of the present study showed that PACs inhibit IL-1β-induced apoptosis and aging of NP cells by activating the PI3K/Akt pathway, and suggested that PACs have therapeutic potential for IDD.

Circ0007042 alleviates intervertebral disc degeneration by adsorbing miR-369 to upregulate BMP2 and activate the PI3K/AKt pathway

Background

To identify regulatory ncRNA molecules that can cause differential expression of CDH2 in intervertebral disc degeneration (IDD) and explore whether there are other ways to affect the progression of IDD.

Methods

A primary culture of human nucleus pulposus (NP) cells was established and identified by immunofluorescence. An in vitro IDD model was constructed by compressing human NP cells, and the MTT assay was used to measure cell viability. Changes in the ncRNA group were analysed by RNA-seq. The expression levels of hsa_circ_7042, CDH2, and miR-369-3p were detected by qPCR. Cell apoptosis, senescence, and extracellular matrix (ECM) metabolism were detected by flow cytometry, β-galactosidase staining, and Western blotting. hsa_circ_7042, miR-369-3p, and bone morphogenetic protein 2 (BMP2) were verified by luciferase and RNA immunoprecipitation (RIP) analyses. The PI3K/Akt pathway was validated by transfection of BMP2 siRNA. Furthermore, a mouse model of lumbar spine instability was constructed. circ_7042 adenovirus was packaged and injected into the intervertebral discs of mice, and the influence of circ_7042 overexpression on intervertebral disc degeneration was determined.

Results

Western blotting, qPCR, and flow cytometry analyses confirmed that overexpression of circ_7042 could downregulate miR-369-3p and upregulate the expression of CDH2 and BMP2 in IDD cell and animal models. Additionally, the levels of apoptotic and senescent cells decreased, and ECM degradation decreased. The PI3K/Akt pathway was significantly activated after circ_7042 was overexpressed. The injection of circ_7042-overexpressing adenovirus effectively reduced ECM degradation and the level of apoptosis in NP tissue.

Conclusions

circ_7042 could upregulate the expression of CDH2 and BMP2 by absorbing miR-369-3p, and the increased BMP2 activated the PI3K/Akt pathway, thus improving IDD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02895-7.

Targeting Autophagy for Developing New Therapeutic Strategy in Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) is a prevalent cause of low back pain. IVDD is characterized by abnormal expression of extracellular matrix components such as collagen and aggrecan. In addition, it results in dysfunctional growth, senescence, and death of intervertebral cells. The biological pathways involved in the development and progression of IVDD are not fully understood. Therefore, a better understanding of the molecular mechanisms underlying IVDD could aid in the development of strategies for prevention and treatment. Autophagy is a cellular process that removes damaged proteins and dysfunctional organelles, and its dysfunction is linked to a variety of diseases, including IVDD and osteoarthritis. In this review, we describe recent research findings on the role of autophagy in IVDD pathogenesis and highlight autophagy-targeting molecules which can be exploited to treat IVDD. Many studies exhibit that autophagy protects against and postpones disc degeneration. Further research is needed to determine whether autophagy is required for cell integrity in intervertebral discs and to establish autophagy as a viable therapeutic target for IVDD.

Upregulation of SIRT1 by Evodiamine activates PI3K/AKT pathway and blocks intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is a major cause of a number of spinal diseases, resulting in serious public health problems. Evodiamine (Evo) is an indole quinazoline alkaloid extracted from Evodia rutaecarpa, which has antioxidant, anti-apoptosis and anti-inflammatory effects. The purpose of the present study was to investigate lipopolysaccharide (LPS)-induced IDD progression in human nucleus pulposus cells (NPCs) and its potential mechanism. The viability and apoptosis of NPCs were detected by Cell Counting Kit-8 (CCK-8) and TUNEL staining, respectively. Western blotting was used to detect the expression levels of proteins, cell transfection was performed to knockdown Sirtuin 1 (SIRT1) and the expression of tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) was detected by enzyme-linked immunosorbent assay kits. The results showed that Evo effectively alleviated LPS-induced NPCs apoptosis and caspase-3 activation and Evo treatment reversed the upregulation of matrix metalloproteinase-13, as well as the downregulation of collagen type II (collagen II), Sry-type high-mobility-group box 9 and aggrecan and reduced the production of pro-inflammatory factors TNF-α and IL-6 in LPS-stimulated NPCs. In addition, treatment with Evo upregulated SIRT1 and activated the PI3K/Akt pathway, knockdown of SIRT1 inhibited the phosphorylation of Akt and PI3K in LPS-stimulated NPCs. In general, Evo upregulated SIRT1 and inhibited LPS-induced NPCs apoptosis, extracellular matrix degradation and inflammation by activating the PI3K/Akt pathway.

The importance of natural chalcones in ischemic organ damage: Comprehensive and bioinformatic analysis review

Over the last few decades, extensive research has been conducted, yielding a detailed account of thousands of newly discovered compounds of natural origin and their biological activities, all of which have the potential to be used for a wide range of therapeutic purposes. There are multiple research papers denoting the central objective of chalcones, which have been shown to have therapeutic potential against various forms of ischemia. The various aspects of chalcones are discussed in this review regarding molecular mechanisms involved in the promising anti-ischemic potential of these chalcones. The main mechanisms involved in these protective effects are Nrf2/Akt activation and NF-κB/TLR4 suppression. Furthermore, in-silico studies were carried out to discover the probable binding of these chalcones to Keap-1 (an inhibitor of Nrf2), Akt, NF-κB, and TLR4 protein molecules. Besides, network pharmacology analysis was conducted to predict the interacting partners of these signals. The obtained results indicated that Nrf2, Akt, NF-κB, and TLR4 are involved in the beneficial anti-ischemic actions of chalcones. Conclusively, the present findings show that chalcones as anti-ischemic agents have a valid rationale. The discussed studies will provide a comprehensive viewpoint on chalcones and can help to optimize their effects in different ischemia. PRACTICAL APPLICATIONS: Ischemic organ damage is an unavoidable pathological condition with a high worldwide incidence. According to the current research progress, natural chalcones have been proved to treat and/or prevent various types of ischemic organ damage by alleviating oxidative stress, inflammation, and apoptosis by different molecular mechanisms. This article displays the comprehensive research progress and the molecular basis of ischemic organ damage pathophysiology and introduces natural chalcones' mechanism in the ischemic organ condition.

Identification of Core Genes and Screening of Potential Targets in Intervertebral Disc Degeneration Using Integrated Bioinformatics Analysis

Background: Intervertebral disc degeneration (IDD), characterized by diverse pathological changes, causes low back pain (LBP). However, prophylactic and delaying treatments for IDD are limited. The aim of our study was to investigate the gene network and biomarkers of IDD and suggest potential therapeutic targets.

Methods: Differentially expressed genes (DEGs) associated with IDD were identified by analyzing the mRNA, miRNA, and lncRNA expression profiles of IDD cases from the Gene Expression Omnibus (GEO). The protein–protein interaction (PPI) network, Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis as well as miRNA–lncRNA–mRNA networks were conducted. Moreover, we obtained 71 hub genes and performed a comprehensive analysis including GO, KEGG, gene set enrichment analysis (GSEA), gene set variation analysis (GSVA), Disease Ontology (DO), methylation analysis, receiver operating characteristic (ROC) curve analysis, immune infiltration analysis, and potential drug identification. We finally used qRT-PCR to verify 13 significant DEGs in normal and degenerative nucleus pulposus cells (NPCs).

Results: We identified 305 DEGs closely related to IDD. The GO and KEGG analyses indicated that changes in IDD are significantly associated with enrichment of the inflammatory and immune response. GSEA analysis suggested that cell activation involved in the inflammatory immune response amide biosynthetic process was the key for the development of IDD. The GSVA suggested that DNA repair, oxidative phosphorylation, peroxisome, IL-6-JAK-STAT3 signaling, and apoptosis were crucial in the development of IDD. Among the 71 hub genes, the methylation levels of 11 genes were increased in IDD. A total of twenty genes showed a high functional similarity and diagnostic value in IDD. The result of the immune cell infiltration analysis indicated that seven genes were closely related to active natural killer cells. The most relevant targeted hub genes for potential drug or molecular compounds were MET and PIK3CD. Also, qRT-PCR results showed that ARHGAP27, C15orf39, DEPDC1, DHRSX, MGAM, SLC11A1, SMC4, and LINC00887 were significantly downregulated in degenerative NPCs; H19, LINC00685, mir-185-5p, and mir-4306 were upregulated in degenerative NPCs; and the expression level of mir-663a did not change significantly in normal and degenerative NPCs.

Conclusion: Our findings may provide new insights into the functional characteristics and mechanism of IDD and aid the development of IDD therapeutics.

Effect of miR124a on collageninduced arthritis in mice and the underlying mechanisms

OBJECTIVES

Rheumatoid arthritis (RA) is a chronic autoimmune disease. MicroRNA has been shown to play an important role in RA. MicroRNA-124a (miR-124a) has anti-proliferative and anti-inflammatory effects in RA fibroblast synovial cells. This study aims to explore the effects of miR-124a overexpression on arthritis in collagen-induced arthritis (CIA) mice and the underlying mechanisms.

METHODS

Bovine type II collagen and complete Ferris adjuvant were used to induce CIA model from DBA/1 mice. Twenty-eight days after initial immunization (D28), CIA mice were randomly divided into a model group, a miR-124a treatment group, and a negative control (NC) group. Physiological saline, miR-124a agomir, and miR-124a agomir NC were injected into the skin at the tail root of mice every 3 days for 4 times, respectively. The degree of joint swelling and arthritis index of mice were recorded accordingly. Sixty-three days after initial immunization (D63), the mice were sacrificed to obtain the synovial tissue of ankle joint. HE staining was used to observe the proliferation of synovial cell, infiltration of inflammatory cell, pannus, and bone erosion of synovial tissues; TUNEL staining was used to detect cell apoptosis; qRT-PCR was used to detect the mRNA expression of miR-124a, phosphatidylinositol-3-kinase catalytic subunit alpha (PIK3CA) and its downstream genes Bcl-2 and Bax. Immunohistochemistry was used to detect the protein expression of PIK3CA, Bcl-2, and Bax protein in synovial tissues of each group.

RESULTS

Different degrees of swelling presented in the paws of DBA/1 mice at D28, which indicated the CIA model was constructed successfully. Forty-eight days after initial immunization (D48), the paws of mice in the miR-124a treatment group were only slightly red and swollen, while the paws of mice in the model group and the NC group were obviously red and swollen. The arthritis index of mice in the miR-124a treatment group were decreased significantly compared to the NC group at D51, D53, D59, and D62 (51, 53, 59, 62 days after initial immunization) (all P<0.05). Sixty-three days after initial immunization (D63), HE staining indicated that the scores of synovial cell proliferation, inflammatory cell infiltration, synovial pannus, and bone erosion were significantly reduced in the miR-124a treatment group (P<0.05 or P<0.01), while cell apoptosis was increased in the miR-124a treatment group compared with the model group and NC group (P<0.01 or P<0.001). Besides, the expression of miR-124a and Bax in the synovial tissue in miR-124a treatment group was significantly higher than those in the model group and NC group (P<0.01 or P<0.001), while the expressions of PIK3CA and Bcl-2 were decreased (P<0.05 or P<0.01 or P<0.001), and the ratio of Bcl-2 to Bax was significantly decreased (P<0.01 or P<0.001).

CONCLUSIONS

Overexpression of miR-124a can reduce arthritis in CIA mice bacause it could promote synovial cell apoptosis and inhibit synovial cell proliferation via targeting PIK3CA and regulating its downstream pathways.

Kukoamine A attenuates lipopolysaccharide-induced apoptosis, extracellular matrix degradation, and inflammation in nucleus pulposus cells by activating the P13K/Akt pathway

Intervertebral disc degeneration (IDD) is the leading cause of back, neck, and radicular pain. This study aims to look at the roles of Kukoamine A (KuA) in nucleus pulposus cells (NPCs) of IDD and its related potential mechanisms. Cell viability of NPCs in the control, lipopolysaccharide (LPS) and LPS+KuA groups was firstly detected by cell counting kit (CCK)-8. Meanwhile, the protein expression of collagen II in LPS-induced NPCs was measured by western blot. Then, the experiments following the treatment of KuA in LPS-induced NPCs included cell proliferation assessment by 5-ethynyl-2’-deoxyuridine (EdU) kit, cell apoptosis and extracellular matrix degradation (ECM) analysis by Terminal dUTP nick-end labeling (TUNEL) and western blot, the detection of inflammatory cytokines by western blot and enzyme-linked immunosorbent assay (ELISA), P13K/Akt pathway-related protein levels analysis by western blot. Finally, after the addition of P13K/Akt pathway inhibitor LY294002, cell apoptosis, ECM and inflammation in KuA-treated NPCs induced by LPS were again examined by the same methods. Results indicated that KuA prevented loss of cell viability and attenuated the apoptosis, ECM, and inflammation in LPS-induced NPCs. Furthermore, western blot experiment verified the activation of KuA on P13K/Akt pathway in LPS-induced NPCs. However, inhibition of P13K/Akt pathway reversed the roles of KuA in LPS-induced NPCs. Thus, KuA attenuates LPS-induced apoptosis, ECM and inflammation in LPS-induced NPCs by activating the P13K/Akt pathway.

The Mechanism and Function of miRNA in Intervertebral Disc Degeneration

Intervertebral disc degeneration (IDD) disease has been considered as the main cause of low back pain (LBP), which is a very common symptom and the leading cause of disability worldwide today. The pathological mechanism of IDD remains quite complicated, and genetic, developmental, biochemical, and biomechanical factors all contribute to the development of the disease. There exists no effective, non-surgical treatment for IDD nowadays, which is largely related to the lack of knowledge of the specific mechanisms of IDD, and the lack of effective specific targets. Recently, non-coding RNA, including miRNA, has been recognized as an important regulator of gene expression. Current studies on the effects of miRNA in IDD have confirmed that a variety of miRNAs play a crucial role in the process of IDD via nucleus pulposus cells (NPC) apoptosis, abnormal proliferation, inflammatory factors, the extracellular matrix (ECM) degradation, and annulus fibrosus (AF) degeneration. In the past 10 years, research on miRNA has been quite active in IDD. This review summarizes the current research progression of miRNA in the IDD and puts forward some prospects and challenges on non-surgical treatment for IDD.

LncRNA HOTAIR influences cell proliferation via miR-130b/PTEN/AKT axis in IDD

Intervertebral disc degeneration (IDD) constitutes the pathological foundation of most musculoskeletal disorders of the spine. Previous studies have noted that cell proliferation is a common feature of IDD. Bioinformatics indicated that aberrantly expressed long non-coding RNAs (lncRNAs) were involved in the development of IDD. In this study, we aimed to investigate the function of lncRNA HOTAIR in the proliferation of human nucleus pulposus (NP) cells of IDD in vitro and further clarified its mechanism. The expression of HOTAIR and miR-130b was quantified by qRT-PCR in nucleus pulposus (NP) tissues. Furthermore, NP cells proliferation were assayed by CCK8 and Immunostaining. Dual-luciferase reporter and RIP assay were used to examine the expression of HOTAIR, PTEN, and their co-target gene miR-130b. Western blotting was used to test AKT expression. Our in vitro experiments on human normal NP cells observed that HOTAIR was significantly dysregulated in IDD. Further, HOTAIR can suppress proliferation by directly targeting miR-130b. In addition, Both HOTAIR and PTEN were confirmed to target miR-130b, and miR-130b upregulation reversed the phenomenon of ectopic expression of HOTAIR. More importantly, HOTAIR upregulation significantly reduced CyclinD1 protein expression by PTEN/AKT signaling pathway. Our findings suggest that HOTAIR may bind to miR-130b and subsequently increased CyclinD1 expression via PTEN/Akt pathway. Thereby, HOTAIR could become a potential target for the treatment of IDD.Abbreviations : IDD; intervertebral disc degeneration ncRNAs; non-coding RNAs lncRNAs; long non-coding RNAs miRNAs; microRNAs NP; nucleus pulposus qRT-PCR; quantitative reverse transcription-PCR LBP; Low back pain ORF; open reading frame HOTAIR; Hox transcript antisense intergenic RNA FAF1; Fas-associated protein factor-1 Erk; extracellular signal-regulated kinase TUG1; Taurine Up-regulated Gene 1 HIF1A hypoxia-inducible factor 1-alpha PI3K; phosphoinositide-3 kinase AIS; adolescent idiopathic scoliosis ECM; extracellular matrix LN;lupus nephritis CT;computed tomography MRI; magnetic resonance imaging PBS; phosphate-buffered salin PBS; phosphate-buffered salin PVDF; polyvinylidene fluoride TBST; Tris-buffered saline Tween ECL; enhanced chemiluminescence RIP; RNA immunoprecipitation.

Causes of and Molecular Targets for the Treatment of Intervertebral Disc Degeneration: A Review

Intervertebral disc degeneration (IVDD) is a pathological condition that can lead to intractable back pain or secondary neurological deficits. There is no fundamental cure for this condition, and current treatments focus on alleviating symptoms indirectly. Numerous studies have been performed to date, and the major strategy for all treatments of IVDD is to prevent cell loss due to programmed or regulated cell death. Accumulating evidence suggests that several types of cell death other than apoptosis, including necroptosis, pyroptosis, and ferroptosis, are also involved in IVDD. In this study, we discuss the molecular pathway of each type of cell death and review the literature that has identified their role in IVDD. We also summarize the recent advances in targeted therapy at the RNA level, including RNA modulations through RNA interference and regulation of non-coding RNAs, for preventing cell death and subsequent IVDD. Therefore, we review the causes and possible therapeutic targets for RNA intervention and discuss the future direction of this research field.

hsa-miR-508-5p as a New Potential Player in Intervertebral Disc Degeneration

Intervertebral disc degeneration (IDD) is widely known as the principal cause of low back pain, diminishing patients' quality of life and imposing a huge economic burden on healthcare systems worldwide. However, the underlying mechanisms of IDD remain to be determined. This study aimed to scrutinize data sets via bioinformatics to identify microRNAs (miRNAs)/genes and pathways associated with IDD. The array profiling of patients with IDD and individuals without IDD was acquired from the Gene Expression Omnibus (GEO) database (viz., GSE19943, GSE63492, and GSE34095). The expression profiles of miRNAs and genes with differential patterns were analyzed using GEO2R. The target genes of the chosen miRNA were then examined, and in silico functional analyses were performed on the signaling pathways and biological processes of the differentially expressed genes. Three human miRNAs were up and downregulated in IDD patients in the examined data sets. Among them, hsa-miR-508-5p had a significant differential expression in the IDD group, and SEC11A, IPO5, FN1, and MRPS10, as the targets of hsa-miR-508-5p, were upregulated in the IDD group. Furthermore, extracellular matrix-receptor interactions, focal adhesion, and actin cytoskeleton regulation were important pathways involved in IDD. Our analysis identified hsa-miR-508-5p as a novel miRNA involved in IDD pathogenies. Our findings not only further confirmed the significant role of miRNAs in IDD pathogenesis but also extended the spectrum of the miRNAs and genes involved in IDD. Though, still, further experimental investigations are needed to confirm our findings.

Annexin A2 promotes development of retinal neovascularization through PI3K/ AKT signaling pathway

PURPOSE

Retinal Neovascularization (RNV) is a pathological characteristic of ocular diseases. Annexin A2 (ANXA2) plays important roles in RNV while the mechanism remains unclear. The study aimed to explore relationship between ANXA2 and PI3K/AKT signaling pathway in RNV.

METHODS

We used human retinal vascular endothelial cells (HRECs) and oxygen-induced retinopathy (OIR) mice model to show ANXA2 can promote the development of RNV through PI3K/AKT signaling pathway. We divided HRECs into six groups by infecting lentivirus containing appropriate plasmid and adding corresponding solution. Assays showing ability of HRECs were performed in vitro. Mice were randomly divided into three groups and treated accordingly.

RESULTS

Expression of ANXA2 and activity of PI3K/AKT signaling pathway in HRECs were detected. RNV and expression of ANXA2 in mice retinas were detected. Results showed that ANXA2 expression is positively related with RNV-forming ability of HRECs in vitro and development of RNV in vivo while low activity of PI3K/AKT signaling pathway could attenuate the role of ANXA2.

CONCLUSIONS

We can make ANXA2 and PI3K/ AKT signaling pathway as a promising target for the regulation of pathological neovascularization of the retina, which also provides a novel idea for effective prevention and treatment of diseases related to RNV in future.

Betulin Alleviates the Inflammatory Response in Mouse Chondrocytes and Ameliorates Osteoarthritis via AKT/Nrf2/HO-1/NF-κB Axis

Osteoarthritis (OA) is a common degenerative joint disease featuring the degeneration, destruction, and ossification of cartilage. Inflammation which may facilitate OA occurrence and development is considered as the main pathological factor. Betulin, a natural product extracted from birch bark, has been commonly used for inflammation treatment; however, its role in OA remains unclear. This study is aimed to explore whether betulin can suppress IL-1β–induced inflammation in chondrocytes and alleviate OA in vitro and in vivo. In in vitro studies, the generation of pro-inflammatory factors, such as interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), prostaglandin E2 (PGE2), and nitric oxide (NO), was assessed using the enzyme-linked immunosorbent assay (ELISA) and Griess reaction. As revealed by results, betulin inhibited the expression of pro-inflammatory mediators. In addition, the protein expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), matrix metalloproteinase (MMP-13), thrombospondin motifs 5 (ADAMTS5), Collagen II, and Aggrecan were quantified using Western blot analysis. We found that betulin could inhibit the generation of COX-2 and iNOS induced by IL-1β, indicating that betulin has anti-inflammatory effects in chondrocytes. Furthermore, betulin downregulates the expression of MMP-13 and ADAMTS-5 and upregulates the expression of Collagen II and Aggrecan, indicating that it can inhibit the degradation of the extracellular matrix. In mechanism, betulin activated the AKT/Nrf2 pathway and inhibited the phosphorylation of p65. In in vivo studies, administration of betulin in vivo could inhibit cartilage destruction and inflammatory progression. Therefore, these findings suggest that betulin may alleviate IL-1β–induced OA via the AKT/Nrf2/HO-1/NF-κB signal axis, and betulin may be a potential drug for the treatment of OA.

Melatonin Suppresses Apoptosis of Nucleus Pulposus Cells through Inhibiting Autophagy via the PI3K/Akt Pathway in a High-Glucose Culture

Diabetes mellitus- (DM-) associated hyperglycemia promotes apoptosis of disc nucleus pulposus (NP) cells, which is a contributor to intervertebral disc degeneration (IDD). Melatonin is able to protect against cell apoptosis. However, its effects on apoptosis of NP cell in a high-glucose culture remain unclear. The purpose of the present study was to investigate the effects and molecular mechanism of melatonin on NP cell apoptosis in a high-glucose culture. NP cells were cultured in the baseline medium supplemented with a high-glucose concentration (0.2 M) for 3 days. The control cells were only cultured in the baseline medium. Additionally, the pharmaceutical inhibitor LY294002 was added along with the culture medium to investigate the possible role of the PI3K/Akt pathway. Apoptosis, autophagy, and activity of the PI3K/Akt pathway of NP cells among these groups were evaluated. Compared with the control NP cells, high glucose significantly increased cell apoptosis ratio and caspase-3/caspase-9 activity and decreased mRNA expression of Bcl-2, whereas it increased mRNA or protein expression of Bax, caspase-3, cleaved caspase-3, cleaved PARP, and autophagy-related molecules (Atg3, Atg5, Beclin-1, and LC3-II) and decreased protein expression of p-Akt compared with the control cells. Additionally, melatonin partly inhibited the effects of high glucose on those parameters of cell apoptosis, autophagy, and activation of PI3K/Akt. In conclusion, melatonin attenuates apoptosis of NP cells through inhibiting the excessive autophagy via the PI3K/Akt pathway in a high-glucose culture. This study provides new theoretical basis of the protective effects of melatonin against disc degeneration in a DM patient.

Uvangoletin, extracted from Sarcandra glabra, exerts anticancer activity by inducing autophagy and apoptosis and inhibiting invasion and migration on hepatocellular carcinoma cells

ETHNOPHARMACOLOGICAL RELEVANCE

Uvangoletin is a dihydrochalcone extracted from the traditional Chinese medicinal plant Sarcandra glabra. Previous research has showed that uvangoletin could induce leukemia cell death. However, the anticancer effect of uvangoletin on hepatocellular carcinoma (HCC) has not been clarified.

AIM OF THE STUDY

This study aimed to investigate the anti-cancer effects of uvangoletin on HCC and to explore its underlying mechanisms.

MATERIALS AND METHODS

We measured the anticancer activities of uvangoletin both in vitro and in vivo by MTT assay and HepG2 xenograft model. The effects of uvangoletin on apoptosis, autophagy, migration and invasion were also determined. Apoptosis was evaluated by flow cytometry method. Autophagy was assessed by immunofluorescence assay. Cell migration and invasion ability were validated by wound healing assay and cultrex® 96 well cell migration/invasion assay. The expression level of relevant proteins and pathways were examined by western blot.

RESULTS

The results of MTT assay and HepG2 xenograft model showed that uvangoletin could inhibit HCC cells proliferation in vitro and in vivo. Uvangoletin could induce HepG2 cell apoptosis as evidence by the increased expression of cleaved caspase 3, caspase 8 and Bax while decreased Bcl-2 expression. Wound healing assay and transwell assay showed that uvangoletin inhibited HepG2 cells migration and invasion and reduced vimentin, MMP9, MMP2 expression. Uvangoletin also promoted autophagy in HepG2 cells as confirmed by the accumulation of GFP-LC3 puncta. Autophagy inhibitors like 3-MA or CQ could suppress uvangoletin-induced apoptosis. Importantly, uvangoletin-induced anti-EMT effect was also attenuated after autophagy inhibitors added in. Mechanistically, the expressions of p-JNK, p-ERK, p-p38, p-AKT, p-p70S6k and p-mTOR were significantly decreased after uvangoletin treatment.

CONCLUSION

Our results showed that uvangoletin could induce apoptotic and autophagic cell death, inhibit cell proliferation and metastasis on HepG2 cells through Akt/mTOR, MAPK and TGFβ/Smad2 signal pathways.

miR-19b-3p relieves intervertebral disc degeneration through modulating PTEN/PI3K/Akt/mTOR signaling pathway

Emerging studies have revealed that non-coding RNAs contribute to regulating intervertebral disc degeneration (IVDD). Here, we intended to probe into the function of miR-19b-3p in IVDD evolvement. The miR-19b-3p level in the intervertebral disc (IVD) tissues of IVDD patients and IL-1β/TNF-α/hydrogen peroxide-treated human nucleus pulposus cells (HNPCs) was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Also, qRT-PCR was conducted to examine the profiles of MMP-3, MMP-9, MMP-13, ADAMTS-4 and ADAMTS-5. The PTEN/PI3K/Akt/mTOR pathway was examined by Western blot (WB). The miR-19b-3p overexpression assay was carried out, and HNPC proliferation and apoptosis were compared by the cell counting kit-8 (CCK-8) assay and flow cytometry (FCM). In addition, the mechanism of action of miR-19b-3p was clarified using the PTEN inhibitor (VO-Ohpic triphosphate) or the mTOR inhibitor (Rapamycin) on the basis of IL-1β intervention and miR-19b-3p mimics transfection. Our results testified that miR-19b-3p expression was curbed in IVD tissues of the IVDD patients (vs. normal IVD tissues) and IL-1β-, TNF-α, or hydrogen peroxide-treated HNPCs. Up-regulating miR-19b-3p enhanced HNPC proliferation and hampered its apoptosis. Moreover, miR-19b-3p dampened the PTEN profile and activated the PI3K/Akt/mTOR pathway. Interestingly, attenuating PTEN reduced IL-1β-, TNF-α-, or hydrogen peroxide-mediated HNPC apoptosis and up-regulated PI3K/Akt/mTOR, while inhibiting the mTOR pathway offset the protective function of miR-19b-3p. Further mechanism studies illustrated that miR-19b-3p targeted the 3'untranslated region (UTR) of PTEN and abated the PTEN level. This research confirmed that miR-19b-3p suppressed HNPC apoptosis in the in-vitro model of IVDD by regulating PTEN/PI3K/Akt/mTOR pathway.

Uncovering the mechanism of the Shenzhi Jiannao formula against vascular dementia using a combined network pharmacology approach and molecular biology

BACKGROUND

Shenzhi Jiannao formula (SZJNF) is a herbal prescription which is used for detoxification, dredging collaterals, and activating blood circulation and Qi flow in traditional Chinese medicine. SZJNF is a clinical effective prescription for the treatment of vascular dementia (VD) first formulated based on the classical theory of traditional Chinese medicine, but its anti-VD mechanism remains ambiguous.

PURPOSE

The aim of this study was to elucidate the multi-target mechanisms of SZJNF against VD using a network pharmacology approach and verify its effects through biological experiments.

STUDY DESIGN AND METHODS

We utilized network pharmacology-based prediction and molecular docking techniques to uncover the potential micro-mechanism of SZJNF against VD. We identified active components and potential targets, and performed network analysis, functional annotation, and pathway enrichment analysis. Subsequently, glutamate-induced PC12 cells and VD rats were used to verify the molecular mechanisms of SZJNF.

RESULTS

Seventeen active compounds were identified in SZJNF rat plasma; moreover, 773 predicted targets and 1544 VD-related targets were found. Various networks, including the PPI, herb-compound-target, and compound-target-pathway network were constructed. A total of 188 shared targets were identified by network topological analysis, which were closely associated to the anti-VD effects of SZJNF. They were also enriched in various biological processes through hypoxia reaction, promotion of cell proliferation, inhibition of apoptosis, neuroactive ligand-receptor interaction, and calcium signaling pathway, as evaluated by the analysis of advanced functions and pathways. SZJNF components docked well with the key targets. Treatment with SZJNF promoted cell proliferation, ameliorated apoptosis and oxidative stress injury, and improved neurological and cognitive abilities.

CONCLUSION

This study comprehensively demonstrated the multi-target mechanisms of SZJNF in VD using network pharmacology and molecular biology experiments. This provides evidence for further mechanistic studies and for the development of SZJNF as a potential treatment for patients with VD.

Interplay between p300 and HDAC1 regulate acetylation and stability of Api5 to regulate cell proliferation

Api5, is a known anti-apoptotic and nuclear protein that is responsible for inhibiting cell death in serum-starved conditions. The only known post-translational modification of Api5 is acetylation at lysine 251 (K251). K251 acetylation of Api5 is responsible for maintaining its stability while the de-acetylated form of Api5 is unstable. This study aimed to find out the enzymes regulating acetylation and deacetylation of Api5 and the effect of acetylation on its function. Our studies suggest that acetylation of Api5 at lysine 251 is mediated by p300 histone acetyltransferase while de-acetylation is carried out by HDAC1. Inhibition of acetylation by p300 leads to a reduction in Api5 levels while inhibition of deacetylation by HDAC1 results in increased levels of Api5. This dynamic switch between acetylation and deacetylation regulates the localisation of Api5 in the cell. This study also demonstrates that the regulation of acetylation and deacetylation of Api5 is an essential factor for the progression of the cell cycle.

Role of lncRNA XIST/microRNA-19/PTEN network in autophagy of nucleus pulposus cells in intervertebral disc degeneration via the PI3K/Akt signaling pathway

Intervertebral disc degeneration (IVDD) is a complicated pathological condition accompanying with low back pain. This study was designed to figure out the mechanism of lncRNA XIST in IVDD. Abnormally expressed lncRNAs in IVDD patients were measured. The correlations among XIST, miR-19 and PTEN were identified. Overexpression and silencing of XIST, miR-19 and PTEN were introduced and their roles in NPC autophagy in vitro were detected. The potential signaling pathway involved in these events was identified. Consequently, high expression of XIST was found in IVDD patients. It induced NPC autophagy and reduced NPC viability. XIST could serve as a competing endogenous RNA (ceRNA) for miR-19 and upregulate PTEN expression. The overexpression of XIST reduced miR-19 expression, which was followed by enhanced PTEN expression. Upregulation of miR-19 increased NPC viability and proliferation, while decreased NPC autophagy that regulated by XIST, while overexpressed PTEN reversed the above changes. Moreover, overexpression of XIST inactivated the PI3k/Akt signaling pathway.

AGE/RAGE in diabetic kidney disease and ageing kidney

Diabetic kidney disease (DKD) is the primary cause of chronic kidney disease that inevitably progress to end-stage kidney disease. Intervention strategies such as blood glucose control is effective for preventing DKD, but many patients with DKD still reach end-stage kidney disease. Although comprehensive mechanisms shed light on the progression of DKD, the most compelling evidence has highlighted that hyperglycemia-related advanced glycation end products (AGEs) formation plays a central role in the pathogenesis of DKD. Pathologically, accumulation of AGEs-mediated receptor for AGEs (RAGE) triggers oxidative stress and inflammation, which is the major deleterious effect of AGEs in host and intestinal microenvironment of diabetic and ageing conditions. The activation of AGEs-mediated RAGE could evoke nicotinamide adenine dinucleotide phosphate oxidase-induced reactive oxygen and nitrogen species production and subsequently give rise to oxidative stress in DKD and ageing kidney. Therefore, targeting RAGE with its ligands mediated oxidative stress and chronic inflammation is considered as an additional intervention strategy for DKD and ageing kidney. In this review, we summarize AGEs/RAGE-mediated oxidative stress and inflammation signaling pathways in DKD and ageing kidney, discussing opportunities and challenges of targeting at AGEs/RAGE-induced oxidative stress that could hold the promising potential approach for improving DKD and ageing kidney.

LncRNA H19 Aggravates Intervertebral Disc Degeneration by Promoting the Autophagy and Apoptosis of Nucleus Pulposus Cells Through the miR-139/CXCR4/NF-κB Axis

The etiology of lumbocrural pain is closely related to intervertebral disc degeneration (IDD). Long noncoding RNAs (lncRNAs) serve crucial roles in IDD progression. This study investigated the effect of lncRNA H19 on autophagy and apoptosis of nucleus pulposus cells (NPCs) in IDD. The rat model of IDD was established. Normal NPCs and degenerative NPCs (DNPCs) were cultured in vitro. H19 expression in IDD rat was detected. DNPCs were treated with si-H19 to evaluate autophagy and apoptosis of DNPCs. The binding relationships between H19 and miR-139-3p, and miR-139-3p and CXCR4 were verified. DNPCs were co-transfected si-H19 and miR-139-3p inhibitor. The phosphorylation of NF-κB pathway-related p65 in DNPCs was detected. LncRNA H19 was upregulated in IDD rats. Downregulation of H19 inhibited autophagy and apoptosis of DNPCs. LncRNA H19 sponged miR-139-3p to inhibit CXCR4 expression. si-H19 and miR-139-3p inhibitor co-treatment induced autophagy and apoptosis, and enhanced CXCR4 expression. si-H19 decreased p-p65 phosphorylation, while si-H19 and miR-139-3p inhibitor co-treatment partially elevated p-p65 phosphorylation. In conclusion, lncRNA H19 facilitated the autophagy and apoptosis of DNPCs by the miR-139-3p/CXCR4/NF-κB axis, thereby aggravating IDD. This study may offer new insights for the management of IDD.

Integrin-mediated interactions with a laminin-presenting substrate modulate biosynthesis and phenotypic expression for cells of the human nucleus pulposus

With aging and pathology, cells of the nucleus pulposus (NP) de-differentiate towards a fibroblast-like phenotype, a change that contributes to degeneration of the intervertebral disc (IVD). Laminin isoforms are a component of the NP extracellular matrix during development but largely disappear in the adult NP tissue. Exposing human adult NP cells to hydrogels made from PEGylated-laminin-111 (PEGLM) has been shown to regulate NP cell behaviors and promote cells to assume a biosynthetically active state with gene/protein expression and morphology consistent with those observed in juvenile NP cells. However, the mechanism regulating this effect has remained unknown. In the present study, the integrin subunits that promote adult degenerative NP cell interactions with laminin-111 are identified by performing integrin blocking studies along with assays of intracellular signaling and cell phenotype. The findings indicate that integrin α3 is a primary regulator of cell attachment to laminin and is associated with phosphorylation of signaling molecules downstream of integrin engagement (ERK 1/2 and GSK3β). Sustained effects of blocking integrin α3 were also demonstrated including decreased expression of phenotypic markers, reduced biosynthesis, and altered cytoskeletal organization. Furthermore, blocking both integrin α3 and additional integrin subunits elicited changes in cell clustering, but did not alter the phenotype of single cells. These findings reveal that integrin- mediated interactions through integrin α3 are critical in the process by which NP cells sense and alter phenotype in response to culture upon laminin and further suggest that targeting integrin α3 has potential for reversing or slowing degenerative changes to the NP cell.

Cardamonin inhibits the progression of oesophageal cancer by inhibiting the PI3K/AKT signalling pathway

Background: Oesophageal cancer is the most common malignant tumour with a poor prognosis, and the current treatment methods are limited. Therefore, identifying effective treatment methods has become a research hotspot. Cardamonin (CAR) is a natural chalcone compound and has been reported to play an anticancer role in several cancers. However, its function in oesophageal cancer and the possible underlying mechanism are still unclear. The purpose of this study was to demonstrate the anticancer effect of CAR on oesophageal cancer in vivo and in vitro and to explore the underlying mechanism.

Materials and Methods: MTT, crystal violet, and colony formation assays were used to detect oesophageal cancer cell proliferation. The effects of CAR on oesophageal cancer cell migration and invasion were detected by wound healing assay and Transwell assay. Hoechst 33258 staining and flow cytometry were used to detect cell apoptosis. Protein expression levels were detected by Western blot. A tumour xenograft model was established to further test the effect of CAR on the growth of oesophageal cancer in vivo.

Results: The results showed that CAR inhibited the proliferation, migration, and invasion of oesophageal cancer cells in a concentration-dependent manner and induced apoptosis. Furthermore, the Western blot assay showed that CAR could suppress metastasis by inhibiting epithelial-mesenchymal transition (EMT) as indicated by downregulated expression of the mesenchymal markers N-cadherin and vimentin, the EMT transcription factor Snail, and matrix metalloproteinases (MMPs) and upregulated expression of the epithelial marker E-cadherin. CAR was associated with upregulation of the pro-apoptotic proteins Bax and Bad and downregulation of the anti-apoptotic protein Bcl-2 and triggered the mitochondrial apoptosis pathway, which in turn promoted caspase-3 activation and subsequent cleavage of PARP; however, the mitochondria-related apoptotic effects induced by CAR were blocked by caspase inhibitor Z-VAD-FMK pretreatment, which prevented programmed cell death triggered by CAR. In addition, CAR reduced the phosphorylation level of downstream effector molecules of phosphatidylinositol 3 kinase (PI3K) in a dose-dependent manner, and treatment with the PI3K agonist 740Y-P could partially reverse the anticancer effect of CAR, demonstrating that CAR played an antitumour role by inhibiting the PI3K/AKT signalling pathway in oesophageal cancer cells. Moreover, the EC9706 xenograft model further confirmed that CAR can significantly inhibit tumour growth in vivo.

Conclusion: In summary, CAR exhibited a strong anticancer effect on human oesophageal cancer cells and promoted apoptosis by inhibiting the PI3K/AKT signalling pathway, suggesting that CAR can be used as new strategy for oesophageal cancer treatment.

Pharmacological inhibition of mTORC1 activity protects against inflammation-induced apoptosis of nucleus pulposus cells

Lumbar disc herniation is a common disease characterized by the degeneration of intervertebral discs (IVDs), accompanied by imbalance of metabolic and inflammatory homeostasis. Current studies establish that IVD degeneration is induced by increased apoptosis of nucleus pulposus (NP) cells. However, the underlying mechanisms of NP cell survival/apoptosis are not well elucidated. Here, we reveal a novel mechanism by which mTORC1 signaling controls NP cell survival through regulating metabolic homeostasis. We demonstrated that hyperactivated mTORC1 activity induced by inflammatory cytokines engenders the apoptosis of NP cells, whereas pharmacological inhibition of mTORC1 activity promotes NP cell survival. Using an integrative approach spanning metabolomics and biochemical approaches, we showed that mTORC1 activation enhanced glucose metabolism and lactic acid production, and therefore caused NP cell apoptosis. Our study identified mTORC1 in NP cells as a novel target for IVD degeneration, and provided potential strategies for clinical intervention of lumbar disc herniation.

The effects of 3D culture on the expansion and maintenance of nucleus pulposus progenitor cell multipotency

INTRODUCTION

Low back pain (LBP) is a global health concern. Increasing evidence implicates intervertebral disk (IVD) degeneration as a major contributor. In this respect, tissue-specific progenitors may play a crucial role in tissue regeneration, as these cells are perfectly adapted to their niche. Recently, a novel progenitor cell population was described in the nucleus pulposus (NP) that is positive for Tie2 marker. These cells have self-renewal capacity and in vitro multipotency potential. However, extremely low numbers of the NP progenitors limit the feasibility of cell therapy strategies.

OBJECTIVE

Here, we studied the influence of the culture method and of the microenvironment on the proliferation rate and the differentiation potential of human NP progenitors in vitro.

METHOD

Cells were obtained from human NP tissue from trauma patients. Briefly, the NP tissue cells were cultured in two-dimensional (2D) (monolayer) or three-dimensional (3D) (alginate beads) conditions. After 1 week, cells from 2D or 3D culture were expanded on fibronectin-coated flasks. Subsequently, expanded NP cells were then characterized by cytometry and tri-lineage differentiation, which was analyzed by qPCR and histology. Moreover, experiments using Tie2+ and Tie2- NP cells were also performed.

RESULTS

The present study aims to demonstrate that 3D expansion of NP cells better preserves the Tie2+ cell populations and increases the chondrogenic and osteogenic differentiation potential compared to 2D expansion. Moreover, the cell sorting experiments reveal that only Tie2+ cells were able to maintain the pluripotent gene expression if cultured in 3D within alginate beads. Therefore, our results highly suggest that the maintenance of the cell's multipotency is mainly, but not exclusively, due to the higher presence of Tie2+ cells due to 3D culture.

CONCLUSION

This project not only might have a scientific impact by evaluating the influence of a two-step expansion protocol on the functionality of NP progenitors, but it could also lead to an innovative clinical approach.

Impact of Hepatoma-Derived Growth Factor Blockade on Resiniferatoxin-Induced Neuropathy

Resiniferatoxin is an ultrapotent capsaicin analog that mediates nociceptive processing; treatment with resiniferatoxin can cause an inflammatory response and, ultimately, neuropathic pain. Hepatoma-derived growth factor, a growth factor related to normal development, is associated with neurotransmitters surrounding neurons and glial cells. Therefore, the study aims to investigate how blocking hepatoma-derived growth factor affects the inflammatory response in neuropathic pain. Serum hepatoma-derived growth factor protein expression was measured via ELISA. Resiniferatoxin was administrated intraperitoneally to induce neuropathic pain in 36 male Sprague-Dawley rats which were divided into three groups (resiniferatoxin+recombinant hepatoma-derived growth factor antibody group, resiniferatoxin group, and control group) (n = 12/group). The mechanical threshold response was tested with calibration forceps. Cell apoptosis was measured by TUNEL assay. Immunofluorescence staining was performed to detect apoptosis of neuron cells and proliferation of astrocytes in the spinal cord dorsal horn. RT-PCR technique and western blot were used to measure detect inflammatory factors and protein expressions. Serum hepatoma-derived growth factor protein expression was higher in the patients with sciatica compared to controls. In resiniferatoxin-group rats, protein expression of hepatoma-derived growth factor was higher than controls. Blocking hepatoma-derived growth factor improved the mechanical threshold response in rats. In dorsal root ganglion, blocking hepatoma-derived growth factor inhibited inflammatory cytokines. In the spinal cord dorsal horn, blocking hepatoma-derived growth factor inhibited proliferation of astrocyte, apoptosis of neuron cells, and attenuated expressions of pain-associated proteins. The experiment showed that blocking hepatoma-derived growth factor can prevent neuropathic pain and may be a useful alternative to conventional analgesics.

SIRT1 Inhibits Apoptosis by Promoting Autophagic Flux in Human Nucleus Pulposus Cells in the Key Stage of Degeneration via ERK Signal Pathway

Background

The application of biomolecular interventions in the early stage of intervertebral disc degeneration (IVDD) is considered an ideal method for the treatment of IVDD. However, the precise definition of the "early stage" of IVDD is unclear. Silent information regulation 2 homologue-1 (SIRT1) can protect human degenerative nucleus pulposus (NP) cells from apoptosis by activating autophagy. However, the mechanism of this effect is still unclear. This study tried to confirm the "early stage" of IVDD and the role of NP cell autophagy during IVDD as well as to determine the mechanism by which SIRT1 protects NP cells.

Methods

The characteristics of the NP in various stages of degeneration were assessed to confirm the "early stage" of IVDD. Then, autophagy and apoptosis were detected in NP cells after SIRT1 upregulation/downregulation. Finally, LY294002 and PD98059 were used to inhibit the AKT/ERK pathway to determine the mechanism by which SIRT1 regulates autophagy in NP cells.

Results

Our data showed that mildly degenerative (Pfirrmann grade III with normal height of intervertebral disc) NP cells may be the key target for biomolecular interventions in IVDD and that SIRT1 protects human mildly degenerative NP cells from apoptosis by activating autophagy via the ERK signalling pathway.

Conclusion

Our data showed that SIRT1 inhibits apoptosis by promoting the autophagic flux in NP cells via the ERK signalling pathway during the key stage of degeneration. These findings will assist in the development of novel therapeutic approaches for IVDD treatment.

Genetic Therapy for Intervertebral Disc Degeneration

Intervertebral disc (IVD) degeneration can cause chronic lower back pain (LBP), leading to disability. Despite significant advances in the treatment of discogenic LBP, the limitations of current treatments have sparked interest in biological approaches, including growth factor and stem cell injection, as new treatment options for patients with chronic LBP due to IVD degeneration (IVDD). Gene therapy represents exciting new possibilities for IVDD treatment, but treatment is still in its infancy. Literature searches were conducted using PubMed and Google Scholar to provide an overview of the principles and current state of gene therapy for IVDD. Gene transfer to degenerated disc cells in vitro and in animal models is reviewed. In addition, this review describes the use of gene silencing by RNA interference (RNAi) and gene editing by the clustered regularly interspaced short palindromic repeats (CRISPR) system, as well as the mammalian target of rapamycin (mTOR) signaling in vitro and in animal models. Significant technological advances in recent years have opened the door to a new generation of intradiscal gene therapy for the treatment of chronic discogenic LBP.

New insights into the interplay between miRNAs and autophagy in the aging of intervertebral discs

Intervertebral disc degeneration (IDD) has been widely known as a main contributor to low back pain which has a negative socioeconomic impact worldwide. However, the underlying mechanism remains unclear. MicroRNAs (miRNAs) are a class of small noncoding RNAs that post-transcriptionally regulate gene expression and serve key roles in the ageing process of intervertebral disc. Autophagy is an evolutionarily conserved process that maintains cellular homeostasis through recycling of nutrients and degradation of damaged or aged cytoplasmic organelles. Autophagy has been proposed as a "double-edged sword" and autophagy dysfunction of IVD cells is considered as a crucial reason of IDD. A rapidly growing number of recent studies demonstrate that both miRNAs and autophagy play important roles in the progression of IDD. Furthermore, accumulated research has indicated that miRNAs target autophagy-related genes and influence the onset and development of IDD. Hence, this review focuses mainly on the current findings regarding the correlations between miRNA, autophagy, and IDD and provides new insights into the role of miRNA-autophagy pathway involved in IDD pathophysiology.

The treatment of intervertebral disc degeneration using Traditional Chinese Medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Intervertebral disc degeneration (IDD) is one of the most common causes of chronic low back pain that spending a lot of workforces and financial resources, seriously affecting human physical and mental health. Clinically used drug treatments and surgical treatments cannot fundamentally relieve the disease and have a risk of recurrence. Traditional Chinese Medicine (TCM) has a history of more than a thousand years in the prevention and treatment of IDD. However, so far, there are few reviews on the treatment of IDD by TCM. Therefore, it is crucial and necessary to systematically mine the existing literature on the treatment of IDD with TCM. This paper strives to systematically describe the modern medicine and TCM theoretical research on IDD, progress in the treatment of IDD and focuses on the treatment of IDD by TCM, which would lay some theoretical foundation and provide new directions for future research.

MATERIALS AND METHODS

Information on clinical observations, animal experiments and relevant pharmacology data about the treatment of IDD were gathered from various sources including traditional Chinese books and Chinese Pharmacopoeia, scientific databases (Elsevier, PubMed, Science Direct, Baidu Scholar, CNKI, Spring Link, Web of Science) and from different professional websites.

RESULTS

This review mainly introduces the current research on the theoretical research on IDD, the combination principle of the TCM formula, and the underlying mechanism of the formula and active ingredients.

CONCLUSIONS

At present, domestic and foreign scholars have carried out a lot of research in different ways, such as the molecular mechanism and predisposing factors of IDD, which provides theoretical development and clinical practice significance for future research. TCM, as a multi-component and multi-targeted drug, can produce synergistic effects to exert its efficacy. Therefore, the development of TCM with more specific functions and practical data will not only become a significant trend in the world market but also has an irreplaceable role in the future treatment of IDD.