Epigenetic modifications in spinal ligament aging

ATF1 and miR-27b-3p drive intervertebral disc degeneration through the PPARG/NF-κB signaling axis

Intervertebral disc degeneration (IDD) is a primary cause of degenerative disc disease; however, the mechanisms underlying it remain unknown. Although great efforts have been made to develop new regenerative therapies, their clinical success is limited. Recent research has indicated that microRNAs (miRNAs) are significantly involved in the progression of IDD. Investigating the role of miRNA intervention in IDD could facilitate the development of therapeutic strategies based on miRNAs. However, circulating miRNAs have not yet been recognized as standard biomarkers for IDD. In this study, we observed that the expression of miR-27b-3p was elevated in the blood and nucleus pulposus (NP) tissue of patients with IDD. Furthermore, reducing the expression of miR-27b-3p was shown to impede the progression of IDD. MiR-27b-3p could reduce the expression of collagen II and ACAN and promote the expression of MMP13 and ADAMT-5 in vitro and in vivo. miR-27b-3p aggravated IDD progression by directly targeting peroxisome proliferator-activated receptor gamma (PPARG), a negative regulator of the NF-κB signal pathway. This study also established that PPARG serves a protective role in IDD. The overexpression of PPARG was able to mitigate the detrimental effects caused by miR-27b-3p in NP cells and animal models of IDD, indicating that miR-27b-3p facilitates the progression of IDD through its interaction with PPARG. Additionally, the transcription factor ATF1 was found to enhance the expression of miR-27b-3p by targeting its promoter region, thereby promoting the degenerative impact of miR-27b-3p on NP cells. Given that miR-27b-3p can promote IDD both in vitro and in vivo, it holds potential as a biomarker, and the inhibition of miR-27b-3p expression may represent a novel therapeutic target for IDD.

Investigating the regulation of the miR-199a-3p/TGF-β/Smad signaling pathway by BSHXF drug-containing serum combined with ADSCs for delaying intervertebral disc degeneration

Background

Intervertebral disc degeneration (IDD) significantly contributes to low back pain (LBP), yet effective treatment options are scarce. BSHXF, a classical traditional Chinese medicine formula, demonstrates dual pharmacological actions: tonifying kidneys, strengthening bones, activating blood circulation, and resolving stasis. It has been widely used in IDD management. Given its potential, combining BSHXF with miRNA regulation and stem cell therapy may enhance therapeutic outcomes by targeting molecular and cellular pathways underlying IDD pathogenesis.

Aim of the study

IDD is recognized as one of the primary causes of low back pain, yet effective therapeutic interventions for this condition remain limited. This study explores the role of BSHXF drug-containing serum combined with adipose-derived stem cells (ADSCs) in slowing IDD progression via the miR-199a-3p/TGF-β/Smad signaling pathway. By comprehensively investigating the synergistic effects of this combination therapy, we aim to propose a novel multi-target strategy that addresses the complex pathogenesis of IDD.

Materials and Methods

This study employed a combination of in vivo and in vitro models. An IDD model was induced in rat caudal intervertebral discs through needle puncture, while an oxidative stress-induced ADSCs injury model was created in vitro using tert-butyl hydroperoxide (T-BHP). Cell viability was measured with the CCK-8 assay. Cell cycle distribution and mitochondrial reactive oxygen species (ROS) levels were assessed using flow cytometry. Cellular senescence was assessed using SA-β-galactosidase staining. Lactate dehydrogenase (LDH) activity was quantified to evaluate cellular damage. Differentiation into nucleus pulposus-like cells was assessed using immunofluorescence double staining for CD73 and COL2A1. ELISA was used to measure inflammatory cytokines (TNF-α, IL-1β, IL-4, IL-10) in cell supernatants. miR-199a-3p expression was determined using RT-qPCR. Western blotting was employed to quantify COL2A1, SOX9, and ACAN protein levels, reflecting nucleus pulposus-like differentiation and extracellular matrix (ECM) synthesis capacity. Western blotting was employed to assess pathway activity by analyzing the protein expressions of TGF-β1, Smad2, Smad3, and their phosphorylated forms, P-Smad2 and P-Smad3. In vivo experiments assessed histopathological degeneration through hematoxylin-eosin (HE) and Safranin O-Fast Green staining. Immunohistochemistry (IHC) analyzed COL1A1 and COL2A1 expression levels. RT-qPCR quantified miR-199a-3p expression. Western blotting was employed to assess the expression levels of TGF-β1, Smad2, Smad3, P-Smad2, and P-Smad3 for pathway regulation evaluation.

Results

Our experimental results demonstrated that serum containing BSHXF significantly alleviated T-BHP-induced oxidative stress, improved the cellular microenvironment, promoted ADSCs proliferation, and decelerated cellular senescence. Further mechanistic analysis revealed that BSHXF significantly activated the TGF-β/Smad signaling pathway, driving the differentiation of ADSCs into nucleus pulposus-like cells and restoring normal cell cycle progression. Overexpression of miR-199a-3p inhibited the TGF-β/Smad pathway, leading to ECM degradation and elevated expression of inflammatory factors (TNF-α, IL-1β). In contrast, BSHXF restored TGF-β/Smad pathway activity by downregulating miR-199a-3p expression. In vivo experiments demonstrated that miR-199a-3p overexpression exacerbated IDD, characterized by reduced COL2A1 expression, elevated COL1A1 levels, and increased disc fibrosis. BSHXF intervention markedly attenuated IDD progression by downregulating miR-199a-3p expression, reducing disc fibrosis, and effectively restoring collagen expression.

Conclusion

BSHXF activated the TGF-β/Smad pathway to promote the differentiation of ADSCs into nucleus pulposus-like cells. It exerted protective effects by alleviating oxidative stress damage, improving the microenvironment, delaying senescence, and enhancing cellular functions. This study is the first to reveal that miR-199a-3p overexpression exacerbates intervertebral disc fibrosis and degeneration. BSHXF restored TGF-β/Smad pathway activity by downregulating miR-199a-3p expression, thereby improving disc structure and function. This integrated approach offers a novel multi-target intervention strategy for IDD, demonstrating significant therapeutic potential.

Circular RNA circSTX12 regulates osteo-adipogenic balance and proliferation of BMSCs in senile osteoporosis

Increased adipogenic differentiation and decreased osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) along with slow self-renewal are pivotal causes for decreased bone formation in senile osteoporosis. Circular RNAs (circRNAs) play important roles in cell proliferation and differentiation, and are closely related to osteoporosis. Whether circRNAs orchestrate the adipo-osteogenic balance and the proliferation of BMSCs in osteoporosis remains unclear. We found in this study that circSTX12 was abnormally upregulated in bone sections from osteoporosis patients and in BMSCs from aged mice, as well as in later-generation human BMSCs in culture. Knockdown of circSTX12 in BMSCs resulted in enhanced osteogenesis, decreased adipogenesis, and increased proliferation capacity; circSTX12 overexpression had the opposite effect. RNA pull-down and mass spectrometry revealed the interactions between circSTX12 with CBL and LMO7. At the molecular level, circSTX12 regulated cell fate in BMSCs by competitively binding to CBL, reducing the ubiquitination-mediated degradation of MST1 and thereby activating the Hippo pathway, a key regulator of adipo-osteogenic balance. Knockdown of circSTX12 promoted the nuclear localization of YAP. In addition, our findings suggest that LMO7 mediates circSTX12-induced BMSCs proliferation by regulating the transcription of CCNA2, CCNH, and CCND1. In vivo, injection of antisense oligonucleotides (ASOs) to knockdown circSTX12 promoted bone formation in aged mice. Our results provide evidence for circSTX12 as a regulator of adipo-osteogenic differentiation and proliferation of BMSCs through binding to CBL and LMO7, respectively. Targeting circSTX12 may be a novel approach for osteoporosis treatment.

N6-Methyladenosine-Modified circSMAD4 Prevents Lumbar Instability Induced Cartilage Endplate Ossification

Lumbar instability causes cartilage endplate ossification and intervertebral disc degeneration. In this study, it is determined that circSMAD4, a Yap1-related circRNA, is stably downregulated under abnormal stress. In vitro, circSMAD4 knockdown resulted in Yap1 mRNA degradation, whereas circSMAD4 overexpression increased Yap1 mRNA expression and nuclear translocation. Hence, the stabilization of circSMAD4 is essential for maintaining the homeostasis of endplate cartilage under abnormal stress. Furthermore, transcriptome sequencing and mass spectrometry analysis revealed that METTL14-mediated N6-methyladenosine (m6A) modification can stabilize circSMAD4 expression. Moreover, circSMAD4 is shown to regulate Yap1 mRNA through the m6A reader IGF2BP1. The IGF2BP1 functions to translocate Yap1 mRNA into the nucleus, which protects endplate chondrocytes from degeneration. Finally, local injection of an AAV5-containing circSMAD4 overexpression plasmid successfully rescued LSI-induced cartilage endplate degeneration, which wasn't observed in Yap1 knockout mice. These findings suggest that m6A-modified circSMAD4 can stabilize Yap1 mRNA expression and translocation, thus preventing degeneration of the cartilage endplate under abnormal stress. Hence, circSMAD4 may become a potential therapeutic tool for managing instability-induced intervertebral disc degeneration.

Single-cell multi-omics analysis identifies SPP1+ macrophages as key drivers of ferroptosis-mediated fibrosis in ligamentum flavum hypertrophy

BACKGROUND

Ligamentum flavum hypertrophy (LFH) is a primary contributor to lumbar spinal stenosis. However, a thorough understanding of the cellular and molecular mechanisms driving LFH fibrotic progression remains incomplete.

METHODS

Single-cell RNA sequencing (scRNA-seq) was performed to construct the single-cell map of human ligamentum flavum (LF) samples. An integrated multi-omics approach, encompassing scRNA-seq, bulk RNA sequencing (bulk RNA-seq), and Mendelian randomization (MR), was applied to conduct comprehensive functional analysis. Clinical tissue specimens and animal models were employed to further confirm the multi-omics findings.

RESULTS

ScRNA-seq provided a single-cell level view of the fibrotic microenvironment in LF, revealing significantly increased proportions of fibroblasts, myofibroblasts, and macrophages in LFH. Using transmission electron microscopy, single-cell gene set scoring, and MR analysis, ferroptosis was identified as a critical risk factor and pathway within LFH. Subcluster analysis of fibroblasts revealed functional heterogeneity among distinct subpopulations, highlighting the functional characteristics and the metabolic dynamics of fibroblast with a high ferroptosis score (High Ferro-score FB). The quantification of gene expression at single-cell level revealed that ferroptosis increased along with fibrosis in LFH specimens, a finding further validated in both human and mice tissue sections. Consistently, bulk RNA-seq confirmed increased proportions of fibroblasts and macrophages in LFH specimens, underscoring a strong correlation between these cell types through Spearman correlation analysis. Notably, subcluster analysis of the mononuclear phagocytes identified a specific subset of SPP1+ macrophages (SPP1+ Mac) enriched in LFH, which exhibited activation of fibrosis and ferroptosis-related metabolic pathways. Cell-cell communication analysis highlighted that SPP1+ Mac exhibited the strongest outgoing and incoming interactions among mononuclear phagocytes in the LFH microenvironment. Ligand-receptor analysis further revealed that the SPP1-CD44 axis could serve as a key mediator regulating the activity of High Ferro-score FB. Multiplex immunofluorescence confirmed substantial Collagen I deposition and reduced Ferritin Light Chain expression in regions with SPP1-CD44 co-localization in LFH specimens.

CONCLUSIONS

Our findings indicated that SPP1+ Mac may contribute to LFH fibrosis by regulating ferroptosis in High Ferro-score FB through the SPP1-CD44 axis. This study enhances our understanding of the cellular and molecular mechanisms underlying LFH progression, potentially improving early diagnostic strategies and identifying new therapeutic targets.

Possible involvement of vitamin K insufficiency in the progression of cervical ossification of the posterior longitudinal ligament

Ossification of the posterior longitudinal ligament of the vertebral column (OPLL) is a disease characterised by ectopic bone formation in the spinal ligament that causes progressive neurological impairment. However, there are no suitable treatments for OPLL. Here, we compared the general characteristics and haemostasis of patients with OPLL and those with cervical spondylotic myelopathy. Those with OPLL had significantly longer prothrombin times and lower plasma protein C concentrations, consistent with vitamin K deficiency. Therefore, we next characterised the effects of vitamin K supplementation on spinal hyperostosis in ttw mice, a model of cervical OPLL, by feeding them standard chow, vitamin K-deficient chow, or standard chow accompanied by biweekly vitamin K2 injections for 6 weeks. We found that vitamin K supplementation resulted in longer stride lengths and superior inter-limb coordination using footprint analysis. Furthermore, supplementation caused a significant reduction in ectopic calcification of the cervical ligaments of the mice, according to microcomputed tomography analysis. Finally, supplementation caused an increase in the number of osteochondrogenic cells expressing Gla-rich protein, an inhibitor of ectopic calcification, and increased the circulating concentration. Thus, vitamin K insufficiency may be involved in the pathogenesis of OPLL and supplementation may represent a novel treatment for this condition.

Epigenetic modification regulates the ligamentum flavum hypertrophy through miR-335-3p/SERPINE2/β-catenin signaling pathway

BACKGROUND

Epigenetic modifications have been proved to play important roles in the spinal degenerative diseases. As a type of noncoding RNA, the microRNA (miRNA) is a vital class of regulatory factor in the epigenetic modifications, while the role of miRNAs in the regulation of epigenetic modifications in ligamentum flavum hypertrophy (LFH) has not been fully investigated.

METHODS

The miRNA sequencing analysis was used to explore the change of miRNA expression during the fibrosis of ligamentum flavum (LF) cells caused by the TGF-β1 (10 ng/ml). The downregulated miRNA miR-335-3p was selected to investigate its effects on the fibrosis of LF cells and explored the accurate relevant mechanisms.

RESULTS

A total of 21 miRNAs were differently expressed during the fibrosis of LF cells. The downregulated miR-335-3p was selected for further investigation. MiR-335-3p was distinctly downregulated in the LFH tissues compared to non-LFH tissues. Overexpression of miR-335-3p could inhibit the fibrosis of LF cells. Further research showed miR-335-3p prevented the fibrosis of LF cells via binding to the 3'-UTR of SERPINE2 to reduce the expression of SERPINE2. The increased SERPINE2 expression might promote the fibrosis of LF cells via the activation of β-catenin signaling pathway to promote the transcription of fibrosis-related genes (ACTA2 and COL3A1).

CONCLUSIONS

Our results revealed that miR-335-3p prevented the fibrosis of LF cells via the epigenetic regulation of SERPINE2/β-catenin signaling pathway. The epigenetic regulator miR-335-3p might be a promising potential target for the treatment of LFH.

The role of H3K27 acetylation in oxygen-glucose deprivation-induced spinal cord injury and potential for neuroprotective therapies

OBJECTIVE

Spinal cord injury (SCI) is a debilitating condition that often results in paralysis and lifelong medical challenges. Research has shown that epigenetic modifications, particularly histone acetylation, play a role in neuroprotection following hypoxic-ischemic events in SCI. The objective of this study was to explore the effects of histone H3K27 acetylation, along with its underlying mechanisms, on the tolerance to hypoxia and ischemia in SCI.

METHODS

This study employed an organotypic spinal cord slice culture model subjected to oxygen-glucose deprivation (OGD). We assessed cell apoptosis and changes in cellular type patterns under these conditions. Following hypoxia and ischemia, we analyzed the expression and distribution of H3K27ac across various nerve cell types. To identify key downstream genes, we integrated ChIP-seq and RNA-seq analyses, investigating molecular mechanisms driving the response to OGD in this model.

RESULTS

OGD stimulation increased cell apoptosis and induced time-dependent changes in the expression patterns of neurons, astrocytes, microglia, and oligodendrocytes in organotypic spinal cord slices, accompanied by a significant reduction in H3K27ac levels. Integrated ChIP-seq and RNA-seq analyses revealed that H3K27ac downregulation under hypoxic and ischemic conditions contributes to spinal cord damage by promoting neuroinflammation and disrupting gene regulation. Furthermore, we identified key downstream targets, including Apoc1, Spp1, Aff1, Brd4, KCNN3, and Rgma, which may represent promising therapeutic targets for SCI.

CONCLUSION

Our data underscore the pivotal role of H3K27ac in the organotypic spinal cord slice culture model following OGD exposure, offering promising avenues for neuroprotective therapies via epigenetic-immune regulation.

CircTMTC1 Mediates Nucleocytoplasmic Translocation of DDX3X to Regulate Osteogenic Differentiation of Human Ligamentum Flavum Cells

OBJECTIVE

This study was aimed to investigate the potential roles of circTMTC1 in the underlying pathophysiological mechanisms of ossification of the ligamentum flavum (OLF).

SUMMARY OF BACKGROUND DATA

OLF is the primary contributor to thoracic spinal stenosis, which may cause severe neurological symptoms. There is a lack of effective medical therapy for OLF available so far because the exact underlying mechanism of OLF has not been fully elucidated. CircRNAs are a special class of noncoding RNAs and have attracted a growing interest of research in various human diseases recently. Therefore, we explored the potential roles of circRNAs in the underlying pathophysiological mechanisms of OLF.

MATERIALS AND METHODS

We performed RNA-seq analysis to investigate the differentially expression profile of circRNAs in osteogenic differentiation of human LF cells, and identified a key circular RNA circTMTC1 functioned in OLF. Subsequently, we performed a series of experiments to investigate the exact molecular and cellular mechanisms in osteogenic differentiation of human ligamentum flavum cells.

RESULTS

CircTMTC1 is significantly upregulated during osteogenic differentiation of human LF cells. Mechanistically, we found that circTMTC1 could interact with the RNA binding protein DDX3X and enhance its nucleocytoplasmic translocation. An increased cytoplasmic level of DDX3X activated the NLRP3 inflammasome pathway and thus promoted osteogenic differentiation of human ligamentum flavum cells.

CONCLUSION

Our findings suggested the circTMTC1-DDX3X-NLRP3 inflammasome signaling plays a pivotal role in osteogenic differentiation of human ligamentum flavum cells, which may provide novel diagnostic and therapeutic strategies for OLF.

Cellular and molecular mechanisms underlying obesity in degenerative spine and joint diseases

Degenerative spine and joint diseases, including intervertebral disc degeneration (IDD), ossification of the spinal ligaments (OSL), and osteoarthritis (OA), are common musculoskeletal diseases that cause pain or disability to the patients. However, the pathogenesis of these musculoskeletal disorders is complex and has not been elucidated clearly to date. As a matter of fact, the spine and joints are not independent of other organs and tissues. Recently, accumulating evidence demonstrates the association between obesity and degenerative musculoskeletal diseases. Obesity is a common metabolic disease characterized by excessive adipose tissue or abnormal adipose distribution in the body. Excessive mechanical stress is regarded as a critical risk factor for obesity-related pathology. Additionally, obesity-related factors, mainly including lipid metabolism disorder, dysregulated pro-inflammatory adipokines and cytokines, are reported as plausible links between obesity and various human diseases. Importantly, these obesity-related factors are deeply involved in the regulation of cell phenotypes and cell fates, extracellular matrix (ECM) metabolism, and inflammation in the pathophysiological processes of degenerative spine and joint diseases. In this study, we systematically discuss the potential cellular and molecular mechanisms underlying obesity in these degenerative musculoskeletal diseases, and hope to provide novel insights for developing targeted therapeutic strategies.

Noncoding RNA as a crucial epigenetic modulator in the degeneration of the ligamentum flavum

Ligamentum flavum degeneration, including hypertrophy and ossification of the ligamentum flavum, leads to degenerative spinal stenosis in older adults. However, the underlying mechanisms of ligamentum flavum degeneration remain unclear, and therapeutic strategies are limited. Noncoding RNAs include microRNAs, circular RNAs, and long noncoding RNAs. As important epigenetic modifications, noncoding RNAs are involved in the progression of several age-related diseases, including ligamentum flavum degeneration. Previous studies have shown that noncoding RNAs can regulate the osteogenic differentiation and fibrosis of ligamentum flavum cells by regulating the expression of related genes. In this review, we discuss noncoding RNAs and their role in ligamentum flavum degeneration.

N6-methyladenosine-modified circCDK14 promotes ossification of the ligamentum flavum via epigenetic modulation by targeting AFF4

BACKGROUND

The ligamentum flavum (LF) is an important anatomical structure of the spine. Ossification of the LF (OLF) has become the leading cause of thoracic spinal stenosis. Circular RNAs (circRNAs) and N6-methyladenosine (m6A) modification are reported to be associated with several human diseases. However, the role of circRNAs and m6A modification in the pathogenesis of OLF has not been fully investigated. Here, we aimed to explore the vital function of circRNAs and m6A modification in OLF.

MATERIALS AND METHODS

We analysed the circRNA expression of 4 OLF tissues and 4 normal LF tissues using bioinformatic analysis and identified circCDK14 for further analysis. We investigated the effects of circCDK14 on the osteogenic differentiation of LF cells. We observed that circCDK14 regulated its target genes by binding to miRNAs as a miRNA sponge. Moreover, the circRNA pull-down assay indicated that RNA-binding proteins might regulate the expression of circCDK14 via m6A modification.

RESULTS

CircCDK14 was significantly upregulated in OLF tissues compared to normal LF tissues. Overexpression of circCDK14 promoted the osteogenic differentiation of LF cells. Mechanistically, CircCDK14 promoted the expression of ALF transcription elongation Factor 4 (AFF4) by serving as a sponge for miR-93-5p. Moreover, Wilms tumour 1-associated protein (WTAP) increased the stability of circCDK14 via N6-methyladenosine modification.

CONCLUSION

The m6A-modified CircCDK14 binding to miR-93-5p played an important role in the osteogenesis of LF cells by targeting AFF4, providing a promising therapeutic target for OLF.

Epigenetic modifications of inflammation in spinal cord injury

Spinal cord injury (SCI) is a central nervous system injury that leads to neurological dysfunction or paralysis, which seriously affects patients' quality of life and causes a heavy social and economic burden. The pathological mechanism of SCI has not been fully revealed, resulting in unsatisfactory clinical treatment. Therefore, more research is urgently needed to reveal its precise pathological mechanism. Numerous studies have shown that inflammation is closely related to various pathological processes in SCI. Inflammatory response is an important pathological process leading to secondary injury, and sustained inflammatory response can exacerbate the injury and hinder the recovery of neurological function after injury. Epigenetic modification is considered to be an important regulatory mechanism in the pathological process of many diseases. Epigenetic modification mainly affects the function and characteristics of genes through the reversibility of mechanisms such as DNA methylation, histone modification, and regulation of non-coding RNA, thus having a significant impact on the pathological process of diseases and the survival state of the body. Recently, the role of epigenetic modification in the inflammatory response of SCI has gradually entered the field of view of researchers, and epigenetic modification may be a potential means to treat SCI. In this paper, we review the effects and mechanisms of different types of epigenetic modifications (including histone modifications, DNA methylation, and non-coding RNAs) on post-SCI inflammation and their potential therapeutic effects on inflammation to improve our understanding of the secondary SCI stage. This review aims to help identify new markers, signaling pathways and targeted drugs, and provide theoretical basis and new strategies for the diagnosis and treatment of SCI.

Evaluation of differences in expression pattern of three isoforms of the transforming growth factor beta in patients with lumbosacral stenosis

The study investigates molecular changes in the lumbosacral (L/S) spine's yellow ligamentum flavum during degenerative stenosis, focusing on the role of transforming growth factor beta 1-3 (TGF-β-1-3). Sixty patients with degenerative stenosis and sixty control participants underwent molecular analysis using real-time quantitative reverse transcription reaction technique (RTqPCR), enzyme-linked immunosorbent assay (ELISA), Western blot, and immunohistochemical analysis (IHC). At the mRNA level, study samples showed reduced expression of TGF-β-1 and TGF-β-3, while TGF-β-2 increased by only 4%. Conversely, at the protein level, the study group exhibited significantly higher concentrations of TGF-β-1, TGF-β-2, and TGF-β-3 compared to controls. On the other hand, at the protein level, a statistically significant higher concentration of TGF-β-1 was observed (2139.33 pg/mL ± 2593.72 pg/mL vs. 252.45 pg/mL ± 83.89 pg/mL; p < 0.0001), TGF-β-2 (3104.34 pg/mL ± 1192.74 pg/mL vs. 258.86 pg/mL ± 82.98 pg/mL; p < 0.0001), TGF-β-3 (512.75 pg/mL ± 107.36 pg/mL vs. 55.06 pg/mL ± 9.83 pg/mL, p < 0.0001) in yellow ligaments obtained from patients of the study group compared to control samples. The study did not establish a significant correlation between TGF-β-1-3 concentrations and pain severity. The findings suggest that molecular therapy aimed at restoring the normal expression pattern of TGF-β-1-3 could be a promising strategy for treating degenerative stenosis of the L/S spine. The study underscores the potential therapeutic significance of addressing molecular changes at the TGF-β isoforms level for better understanding and managing degenerative spinal conditions.

Epigenetic modifiers as game changers for healthy ageing

Epigenetic alterations during ageing are manifested with altered gene expression linking it to lifespan regulation, genetic instability, and diseases. Diet and epigenetic modifiers exert a profound effect on the lifespan of an organism by modulating the epigenetic marks. However, our understanding of the multifactorial nature of the epigenetic process during ageing and the onset of disease conditions as well as its reversal by epidrugs, diet, or environmental factors is still mystifying. This review covers the key findings in epigenetics related to ageing and age-related diseases. Further, it holds a discussion about the epigenetic clocks and their implications in various age-related disease conditions including cancer. Although, epigenetics is a reversible process how fast the epigenetic alterations can revert to normal is an intriguing question. Therefore, this paper touches on the possibility of utilizing nutrition and MSCs secretome to accelerate the epigenetic reversal and emphasizes the identification of new therapeutic epigenetic modifiers to counter epigenetic alteration during ageing.

Incidence and risk factors of dural ossification in patients with thoracic ossification of the ligamentum flavum

OBJECTIVE

Dural ossification (DO) is a common clinical feature in patients with thoracic ossification of the ligamentum flavum (OLF) and associated with the increased risk of perioperative complications. However, few studies have been conducted to determine the incidence and independent risk factors of DO in patients with thoracic OLF. The aim of this retrospective study was to determine the incidence and independent risk factors of DO in patients with thoracic OLF.

METHODS

A total of 107 patients with thoracic OLF who were admitted to the authors' hospital from December 2020 to December 2021 were included in this study. The independent risk factors of DO in patients with thoracic OLF were determined through univariate analysis followed by multivariate logistic regression analysis with p < 0.05. The diagnostic efficacy of the DO in OLF (DO-OLF) risk classification model was determined on the basis of independent risk factors and evaluated on the basis of sensitivity, specificity, and agreement rate.

RESULTS

The incidence of DO in patients with thoracic OLF was 35% (37/107 patients). The tuberous type according to the Sato classification (OR 9.75, p < 0.01) and larger (≥ 9°) supine local kyphosis angle (LKA) (OR 8.13, p < 0.01) were two independent risk factors of DO in thoracic OLF. The DO-OLF risk classification, a novel approach for the diagnosis of DO in patients with thoracic OLF, was established on the basis of the combination of the tuberous type according to the Sato classification and larger supine LKA. The sensitivity, specificity, and agreement rate of this approach for distinguishing between patients with thoracic OLF at high and low risk of DO were 87%, 93%, and 91%, respectively.

CONCLUSIONS

The incidence of DO in patients with thoracic OLF was 35%. The tuberous type according to the Sato classification and larger supine LKA (≥ 9°) were independent risk factors of DO in patients with thoracic OLF. The novel DO-OLF risk classification approach could serve as an efficient method for predicting DO in patients with thoracic OLF.

The Nrf2 antioxidant defense system in intervertebral disc degeneration: Molecular insights

Intervertebral disc degeneration (IDD) is a common degenerative musculoskeletal disorder and is recognized as a major contributor to discogenic lower back pain. However, the molecular mechanisms underlying IDD remain unclear, and therapeutic strategies for IDD are currently limited. Oxidative stress plays pivotal roles in the pathogenesis and progression of many age-related diseases in humans, including IDD. Nuclear factor E2-related factor 2 (Nrf2) is a master antioxidant transcription factor that protects cells against oxidative stress damage. Nrf2 is negatively modulated by Kelch-like ECH-associated protein 1 (Keap1) and exerts important effects on IDD progression. Accumulating evidence has revealed that Nrf2 can facilitate the transcription of downstream antioxidant genes in disc cells by binding to antioxidant response elements (AREs) in promoter regions, including heme oxygenase-1 (HO-1), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and NADPH quinone dehydrogenase 1 (NQO1). The Nrf2 antioxidant defense system regulates cell apoptosis, senescence, extracellular matrix (ECM) metabolism, the inflammatory response of the nucleus pulposus (NP), and calcification of the cartilaginous endplates (EP) in IDD. In this review, we aim to discuss the current knowledge on the roles of Nrf2 in IDD systematically.

Insights into the activity of a protein that regulates gene expression and protects cells against oxidative stress could yield novel treatments for lower back pain. Intervertebral disc degeneration (IDD) is a common cause of lower back pain, but the molecular mechanisms underlying IDD are unclear, meaning treatment options are limited. Oxidative stress is implicated in IDD, and scientists have begun exploring the role of nuclear factor E2-related factor 2 (Nrf2), a master regulator of the body’s antioxidant responses, in regulating IDD progression. In a review of recent research, Weishi Li at Peking University Third Hospital, Beijing, China, and co-workers point out that boosting the activity of Nrf2-related signaling pathways alleviates oxidative stress in intervertebral disc cells. The researchers suggest that therapies based on non-coding RNAs may prove valuable in activating Nrf2 in IDD patients.

High Systemic Immune-Inflammation Index and Body Mass Index Are Independent Risk Factors of the Thoracic Ossification of the Ligamentum Flavum

Background

Inflammation has been considered to play an important role in the pathogenesis of the thoracic ossification of the ligamentum flavum (OLF). However, the inflammation-related risk factors of thoracic OLF have not been fully investigated to date.

Methods

A total of 95 patients (48 in the OLF group and 47 in the control group) were included in this retrospective study to explore the independent risk factors of thoracic OLF. The following demographic and clinical variables were compared between the two groups: gender, age, body mass index (BMI), coexistence of hypertension or diabetes, and inflammation-related variables. Multivariate logistic regression analysis was utilized to determine the independent risk factors.

Results

High systemic immune-inflammation index (SII) (≥621) (odds ratio [OR] = 12.16, 95% confidence interval [CI] = 2.95-50.17, p < 0.01) and BMI (≥25 kg/m2) (OR = 9.17, 95%CI = 3.22-26.08, p < 0.01) were independent risk factors of thoracic OLF. SII (R = 0.38, p < 0.01) and BMI (R = 0.46, p < 0.01) were positively associated with OLF score.

Conclusion

High SII and BMI were the independent risk factors of thoracic OLF. Multicenter prospective studies with a large population should be conducted in the future to verify our findings.

Recent Advances in Epigenetics of Age-Related Kidney Diseases

Renal aging has attracted increasing attention in today’s aging society, as elderly people with advanced age are more susceptible to various kidney disorders such as acute kidney injury (AKI) and chronic kidney disease (CKD). There is no clear-cut universal mechanism for identifying age-related kidney diseases, and therefore, they pose a considerable medical and public health challenge. Epigenetics refers to the study of heritable modifications in the regulation of gene expression that do not require changes in the underlying genomic DNA sequence. A variety of epigenetic modifiers such as histone deacetylases (HDAC) inhibitors and DNA methyltransferase (DNMT) inhibitors have been proposed as potential biomarkers and therapeutic targets in numerous fields including cardiovascular diseases, immune system disease, nervous system diseases, and neoplasms. Accumulating evidence in recent years indicates that epigenetic modifications have been implicated in renal aging. However, no previous systematic review has been performed to systematically generalize the relationship between epigenetics and age-related kidney diseases. In this review, we aim to summarize the recent advances in epigenetic mechanisms of age-related kidney diseases as well as discuss the application of epigenetic modifiers as potential biomarkers and therapeutic targets in the field of age-related kidney diseases. In summary, the main types of epigenetic processes including DNA methylation, histone modifications, non-coding RNA (ncRNA) modulation have all been implicated in the progression of age-related kidney diseases, and therapeutic targeting of these processes will yield novel therapeutic strategies for the prevention and/or treatment of age-related kidney diseases.