High glucose mediates the ChREBP/p300 transcriptional complex to activate proapoptotic genes Puma and BAX and contributes to intervertebral disc degeneration

Downregulation of VEGFA accelerates AGEs-mediated nucleus pulposus degeneration through inhibiting protective mitophagy in high glucose environments

Intervertebral disc degeneration (IVDD) contributes largely to low back pain. Recent studies have highlighted the exacerbating role of diabetes mellitus (DM) in IVDD, mainly due to the influence of hyperglycemia (HG) or the accumulation of advanced glycation end products (AGEs). Vascular endothelial growth factor A (VEGFA) newly assumed a distinct impact in nonvascular tissues through mitophagy regulation. However, the combined actions of HG and AGEs on IVDD and the involved role of VEGFA remain unclear. We confirmed the potential relation between VEGFA and DM through bioinformatics and biological specimen detection. Then we observed that AGEs induced nucleus pulposus (NP) cell degeneration by upregulating cellular reactive oxygen species (ROS), and HG further aggravated ROS level through breaking AGEs-induced protective mitophagy. Furthermore, this adverse effect could be strengthened by VEGFA knockdown. Importantly, we identified that the regulation of VEGFA and mitophagy were vital mechanisms in AGEs-HG-induced NP cell degeneration through Parkin/Akt/mTOR and AMPK/mTOR pathway. Additionally, VEGFA overexpression through local injection with lentivirus carrying VEGFA plasmids significantly alleviated NP degeneration and IVDD in STZ-induced diabetes and puncture rat models. In conclusion, the findings first confirmed that VEGFA protects against AGEs-HG-induced IVDD, which may represent a therapeutic strategy for DM-related IVDD.

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.

Emerging role and therapeutic implications of p53 in intervertebral disc degeneration

Lower back pain (LBP) is a common degenerative musculoskeletal disease that imposes a huge economic burden on both individuals and society. With the aggravation of social aging, the incidence of LBP has increased globally. Intervertebral disc degeneration (IDD) is the primary cause of LBP. Currently, IDD treatment strategies include physiotherapy, medication, and surgery; however, none can address the root cause by ending the degeneration of intervertebral discs (IVDs). However, in recent years, targeted therapy based on specific molecules has brought hope for treating IDD. The tumor suppressor gene p53 produces a transcription factor that regulates cell metabolism and survival. Recently, p53 was shown to play an important role in maintaining IVD microenvironment homeostasis by regulating IVD cell senescence, apoptosis, and metabolism by activating downstream target genes. This study reviews research progress regarding the potential role of p53 in IDD and discusses the challenges of targeting p53 in the treatment of IDD. This review will help to elucidate the pathogenesis of IDD and provide insights for the future development of precision treatments.

Diagnostic model based on key autophagy-related genes in intervertebral disc degeneration

BACKGROUND

Current research on autophagy is mainly focused on intervertebral disc tissues and cells, while there is few on human peripheral blood sample. therefore, this study constructed a diagnostic model to identify autophagy-related markers of intervertebral disc degeneration (IVDD).

METHODS

GSE150408 and GSE124272 datasets were acquired from the Gene Expression Omnibus database, and differential expression analysis was performed. The IVDD-autophagy genes were obtained using Weighted Gene Coexpression Network Analysis, and a diagnostic model was constructed and validated, followed by Gene Set Variation Analysis (GSVA) and Gene Set Enrichment Analysis (GSEA). Meanwhile, miRNA-gene and transcription factor-gene interaction networks were constructed. In addition, drug-gene interactions and target genes of methylprednisolone and glucosamine were analyzed.

RESULTS

A total of 1,776 differentially expressed genes were identified between IVDD and control samples, and the composition of the four immune cell types was significantly different between the IVDD and control samples. The Meturquoise and Mebrown modules were significantly related to immune cells, with significant differences between the control and IVDD samples. A diagnostic model was constructed using five key IVDD-autophagy genes. The area under the curve values of the model in the training and validation datasets were 0.907 and 0.984, respectively. The enrichment scores of the two pathways were significantly different between the IVDD and healthy groups. Eight pathways in the IVDD and healthy groups had significant differences. A total of 16 miRNAs and 3 transcription factors were predicted to be of great value. In total, 84 significantly related drugs were screened for five key IVDD-autophagy genes in the diagnostic model, and three common autophagy-related target genes of methylprednisolone and glucosamine were predicted.

CONCLUSION

This study constructs a reliable autophagy-related diagnostic model that is strongly related to the immune microenvironment of IVD. Autophagy-related genes, including PHF23, RAB24, STAT3, TOMM5, and DNAJB9, may participate in IVDD pathogenesis. In addition, methylprednisolone and glucosamine may exert therapeutic effects on IVDD by targeting CTSD, VEGFA, and BAX genes through apoptosis, as well as the sphingolipid and AGE-RAGE signaling pathways in diabetic complications.

A high throughput screen for pharmacological inhibitors of the carbohydrate response element

A central regulator of metabolism, transcription factor carbohydrate response element binding protein (ChREBP) senses and responds to dietary glucose levels by stimulating the transcription of glycolytic and lipogenic enzymes. Genetic depletion of ChREBP rescues β-cell dysfunction arising from high glucose levels, suggesting that inhibiting ChREBP might represent an attractive therapeutic approach to manage diabetes and other metabolic diseases. However, the molecular mechanisms governing ChREBP activation are poorly understood and chemical tools to probe the cellular activity of ChREBP are lacking. Here, we report a high-throughput pharmacological screen in INS-1E β-cells that identified novel inhibitors of ChREBP-driven transcription at carbohydrate response element sites, including three putative covalent inhibitors and two likely non-covalent chemical scaffolds. This work affords a pharmacological toolkit to help uncover the signaling logic controlling ChREBP activation and may ultimately reveal potential therapeutic approaches for treating metabolic disease.

P300 increases CSNK2A1 expression which accelerates colorectal cancer progression through activation of the PI3K-AKT-mTOR axis

Casein kinase 2 alpha 1 (CSNK2A1) is a known oncogene, but its role in the progression of colorectal cancer (CRC) remain undefined. Here, we investigated the effects of CSNK2A1 during CRC development. In the current study, CSNK2A1 expression in the colorectal cancer cell lines (HCT116, SW480, HT29, SW620 and Lovo) vs. normal colorectal cell line (CCD841 CoN) were compared via RT-qPCR and western blotting. The role of CSNK2A1 on CRC growth and metastases were investigated through Transwell assay. Immunofluorescence analysis was used to investigate the expression of EMT-related proteins. The association between P300/H3K27ac and CSNK2A1 were analyzed using UCSC bioinformatics and Chromatin-immunoprecipitation (Ch-IP) assays. Results revealed that both the mRNA and protein levels of CSNK2A1 in HCT116, SW480, HT29, SW620 and Lovo cells were upregulated. Additionally, P300-mediated H3K27ac activation at the CSNK2A1 promoter was found to drive the increase in CSNK2A1 expression. Transwell assay showed that CSNK2A1 overexpression increased the migration and invasion of HCT116 and SW480 cells, which decreased following CSNK2A1 silencing. CSNK2A1 was also found to facilitate EMT in HCT116 cells, evidenced by the increases of N-cadherin, Snail and Vimentin expression, and loss of E-cadherin. Importantly, the levels of p-AKT-S473/AKT, p-AKT-T308/AKT, and p-mTOR/mTOR in cells overexpressing CSNK2A1 were high, but significantly decreased following CSNK2A silencing. The PI3K inhibitor BAY-806946 could reverse the increase in p-AKT-S473/AKT, p-AKT-T308/AKT, p-mTOR/mTOR induced by CSNK2A1 overexpression and suppress CRC cell migration and invasion. In conclusion, we report a positive feedback mechanism through which P300 enhances CSNK2A1 expression and accelerates CRC progression through the activation of the PI3K-AKT-mTOR axis.

Glucose-stimulated PGC-1α couples with CBP and Runx2 to mediate intervertebral disc degeneration through transactivation of ADAMTS4/5 in diet-induced obesity mice

Emerging evidence suggests that type 2 diabetes mellitus (T2DM) is associated with the pathogenesis of intervertebral disc degeneration (IDD). However, it is still unclear how T2DM contributes to IDD. Herein, we observed the accumulation of blood glucose and degenerative lumbar discs in mice fed a high-fat diet. Detection of differentially expressed genes in degenerative lumbar discs revealed that ADAMTS4 (A Disintegrin and Metalloproteinase with Thrombospondin motifs) and ADAMTS5 genes were significantly increased. In vitro analyses demonstrated that Runt-Related Transcription Factor 2 (Runx2) recruited both PPARgamma Coactivator 1alpha (PGC-1α) and CREB-Binding Protein (CBP) to transactivate the expression of ADAMTS4/5. Glucose stimulation could dose-dependently induce the accumulation of PGC-1α and promoted the binding of the CBP-PGC-1α-Runx2 complex to the promoters of ADAMTS4/5. Depletion of CBP-PGC-1α-Runx2 complex members and treatment with either PGC-1α inhibitor SR-18292 or CBP inhibitor EML425 in vitro could dramatically inhibit the glucose-induced expression of ADAMTS4/5. Administration of SR-18292 and EML425 in diabetic mice could prevent the degeneration of lumbar discs. Collectively, our results revealed a molecular mechanism by which the hyperglycemia-dependent CBP-PGC-1α-Runx2 complex was required for the transactivation of ADAMTS4/5. The blockage of this complex in diabetic mice may help prevent IDD.

Pharmacological Effects of Resveratrol in Intervertebral Disc Degeneration: A Literature Review

Intervertebral disc degeneration (IDD) is a high incidence disease of musculoskeletal system that often leads to stenosis, instability, pain and even deformity of the spinal segments. IDD is an important cause of discogenic lower back pain and often leads to large economic burden to families and society. Currently, the treatment of IDD is aimed at alleviating symptoms rather than blocking or reversing pathological progression of the damaged intervertebral disc. Resveratrol (RSV) is a polyphenol phytoalexin first extracted from the Veratrum grandiflflorum O. Loes and can be found in various plants and red wine. Owing to the in-depth study of pharmacological mechanisms, the therapeutic potential of RSV in various diseases such as osteoarthritis, neurodegenerative diseases, cardiovascular diseases and diabetes have attracted the attention of many researchers. RSV has anti-apoptotic, anti-senescent, anti-inflammatory, anti-oxidative, and anabolic activities, which can prevent further degeneration of intervertebral disc cells and enhance their regeneration. With high safety and various biological functions, RSV might be a promising candidate for the treatment of IDD. This review summarizes the biological functions of RSV in the treatment of IDD and to facilitate further research.

Role of Caspase Family in Intervertebral Disc Degeneration and Its Therapeutic Prospects

Intervertebral disc degeneration (IVDD) is a common musculoskeletal degenerative disease worldwide, of which the main clinical manifestation is low back pain (LBP); approximately, 80% of people suffer from it in their lifetime. Currently, the pathogenesis of IVDD is unclear, and modern treatments can only alleviate its symptoms but cannot inhibit or reverse its progression. However, in recent years, targeted therapy has led to new therapeutic strategies. Cysteine-containing aspartate proteolytic enzymes (caspases) are a family of proteases present in the cytoplasm. They are evolutionarily conserved and are involved in cell growth, differentiation, and apoptotic death of eukaryotic cells. In recent years, it has been confirmed to be involved in the pathogenesis of various diseases, mainly by regulating cell apoptosis and inflammatory response. With continuous research on the pathogenesis and pathological process of IVDD, an increasing number of studies have shown that caspases are closely related to the IVDD process, especially in the intervertebral disc (IVD) cell apoptosis and inflammatory response. Therefore, herein we study the role of caspases in IVDD with respect to the structure of caspases and the related signaling pathways involved. This would help explore the strategy of regulating the activity of the caspases involved and develop caspase inhibitors to prevent and treat IVDD. The aim of this review was to identify the caspases involved in IVDD which could be potential targets for the treatment of IVDD.