Extracellular Matrix Degradation Research Articles

Esculin Alleviates Osteoarthritis Progression Through theSirt1/NF-κB Pathway.

Osteoarthritis (OA), a joint disease associated with inflammatory processes, contributes to joint destruction. Esculin (ESC) extracted from the stem bark of Fraxinus rhynchophylla Hance has been shown to possess anti-inflammatory properties. In this study, we investigated the effect of ESC on chondrocytes treated with IL-1β and its molecular mechanism. The importance and potential mechanism of ESC in the progression of OA were evaluated. The viability of chondrocytes after exposure to ESC was examined through the CCK-8 assays. The cells were then subjected to quantitative polymerase chain reaction (qPCR), western blot, and enzyme-linked immunosorbent assay (ELISA) techniques to analyze the degradation of the extracellular matrix (ECM) and occurrence of inflammation. The NF-κB mechanism was evaluated by western blot analysis, immunofluorescence (IF), and luciferase reporter assay. Molecular docking was performed to allow for predictions on proteins that interact with ESC. Moreover, the significance of Sirt1 was explored through a knockdown experiment based on siRNA. Micro-computed tomography (CT), H&E, Safranin O-Fast Green (S-O), and immunohistochemical analyses were carried out to assess the treatment efficacy of ESC on OA in destabilization of medial meniscus (DMM) models. ESC treatment effectively inhibited ECM degradation, modulated the levels of pro-inflammatory factors, and regulated the NF-κB signaling in chondrocytes exposed to IL-1β. Mechanistically, we found that ESCs bound to Sirt1 to inhibit the activity of the NF-κB mechanism. Furthermore, ESC treatment suppressed OA progression in the DMM models. Our findings reveal that ESC ameliorates OA progression via modulating the Sirt1/NF-κB axis. This demonstrates that ESC has the potential to be applied in the treatment of OA.

Vinpocetine protects against osteoarthritis by inhibiting ferroptosis and extracellular matrix degradation via activation of the Nrf2/GPX4 pathway

BackgroundOsteoarthritis (OA) is a progressive joint condition marked by the slow degradation of articular cartilage. Vinpocetine (Vin), a synthetic derivative of vincamine derived from the vinca plant, exhibits anti-inflammatory and antioxidant properties. Nevertheless, the specific role and mechanism of Vin in the treatment of OA remain largely unexplored. ObjectivesThe study is designed to uncover the impacts of Vin on tert‑butyl hydroperoxide (TBHP)-induced ferroptosis and to explore its potential role and underlying mechanisms in the treatment of OA. Concurrently, we established an OA mouse model through medial meniscal instability surgery to assess the therapeutic effects of Vin in vivo. MethodsThrough network pharmacology analysis, we have identified the key targets and potential pathways of Vin. To simulate an oxidative stress-induced OA environment in vitro, we induced chondrocyte injury using TBHP. We tested how Vin affects chondrocytes under TBHP induction by DHE and DCFH-DA probes, BODIPY-C11 and FerroOrange staining, mitochondrial function assessment, Western blotting, co-immunoprecipitation, and immunofluorescence techniques. Simultaneously, we established an OA mouse model through medial meniscal instability surgery to assess the in vivo therapeutic effects of Vin. In this model, we used X-ray and micro-CT imaging, SO staining, TB staining, H&E staining, and immunohistochemistry to analyze the role of Vin in detail. ResultsThis study demonstrated that Vin effectively suppressed TBHP-induced ferroptosis and extracellular matrix (ECM) degradation and significantly lessened mitochondrial damage associated with ferroptosis. In the OA mouse model, Vin improved cartilage degeneration, subchondral remodeling, synovitis, and ECM degradation. Vin worked by activating the Nrf2/GPX4 pathway and inhibiting the Keap1-Nrf2 interaction. This study focused on the function of ferroptosis in OA and its influence on chondrocyte damage and disease progression, offering novel perspectives on potential treatments. ConclusionVin activated the Nrf2/GPX4 pathway, thereby slowing OA progression, inhibiting ferroptosis, and preventing ECM degradation.

Circulating Matrix Metalloproteinases for Prediction of Aortic Dilatation in Children with Bicuspid Aortic Valve: A Single-Center, Observational Study

Circulating biomarkers have been proposed for early identification of aortic dilatation progression associated with bicuspid aortic valve (BAV), but matrix metalloproteinases (MMPs) are distinguished as signatures of increased extracellular matrix degradation, a landmark of aneurysm formation. The current study aims to identify the role of MMP-1, MMP-2, MMP-9, and the MMP inhibitor, TIMP-1, in identifying aortic dilation in children with BAV. We conducted a study on 73 children divided into two study groups, depending on the presence of aortic dilatation (group 1–43 BAV controls and group 2–30 children with BAV and aortic dilatation). Each patient underwent a cardiac ultrasound and, in each case, serum MMP-1, MMP-2, MMP-9, and TIMP-1 were quantified using xMAP technology. Comparison of the MMPs between the two study groups revealed significantly higher values only in the case of TIMP-1, among BAV controls. Moreover, the same TIMP-1 inversely correlated with aortic annulus absolute size and z score, as well as with ascending aorta z score. No particular correlation between the aortic phenotype and the presence of aortic dilatation was found. Future longitudinal research starting at pediatric ages could show the significance of MMPs screening in BAV individuals as predictors of aortic aneurysm formation.

Spatial proteomics and transcriptomics of the maternal-fetal interface in placenta accreta spectrum

In severe Placenta Accreta Spectrum (PAS), trophoblasts gain deep access in the myometrium (placenta increta). This study investigated alterations at the fetal-maternal interface in PAS cases using a systems biology approach consisting of immunohistochemistry, spatial transcriptomics and proteomics. We identified spatial variation in the distribution of CD4+, CD3+ and CD8+ T-cells at the maternal-interface in placenta increta cases. Spatial transcriptomics identified transcription factors involved in promotion of trophoblast invasion such as AP-1 subunits ATF-3 and JUN, and NFKB were upregulated in regions with deep myometrial invasion. Pathway analysis of differentially expressed genes demonstrated that degradation of extracellular matrix (ECM) and class 1 MHC protein were increased in increta regions, suggesting local tissue injury and immune suppression. Spatial proteomics demonstrated that increta regions were characterised by excessive trophoblastic proliferation in an immunosuppressive environment. Expression of inhibitors of apoptosis such as BCL-2 and fibronectin were increased, while CTLA-4 was decreased and increased expression of PD-L1, PD-L2 and CD14 macrophages. Additionally, CD44, which is a ligand of fibronectin that promotes trophoblast invasion and cell adhesion was also increased in increta regions. We subsequently examined ligand receptor interactions enriched in increta regions, with interactions with ITGβ1, including with fibronectin and ADAMS, emerging as central in increta. These ITGβ1 ligand interactions are involved in activation of epithelial–mesenchymal transition and remodelling of ECM suggesting a more invasive trophoblast phenotype. In PAS, we suggest this is driven by fibronectin via AP-1 signalling, likely as a secondary response to myometrial scarring.

Omega-3 fatty acids protect cartilage from acute injurie by reducing the mechanical sensitivity of chondrocytes

Acute cartilage injuries, such as intra-articular fractures and blunt impacts, frequently result in chondrocyte death and extracellular matrix (ECM) degradation, significantly elevating the risk of post-traumatic osteoarthritis (PTOA). Despite advances in treatment, no effective therapies currently exist to fully cure PTOA or halt its progression. This study explores the protective effects of the dietary fatty acid eicosapentaenoic acid (EPA) on human primary chondrocytes (HPCs) and cartilage explants exposed to mechanical overload and blunt trauma. HPCs were isolated and subjected to mechanical stretching using BioFlex six-well culture plates, while cartilage explants were subjected to impact loading via a customized drop tower. EPA was incorporated into the culture medium, followed by assays to evaluate cell viability, calcium (Ca²⁺) influx, apoptosis, reactive oxygen species (ROS) levels, and collagen type II alpha (Col-2a) expression. EPA treatment markedly decreased chondrocyte mechanical sensitivity, as demonstrated by enhanced cell viability and reduced lactate dehydrogenase (LDH) release. Furthermore, EPA inhibited Piezo1 activation, leading to lower intracellular Ca²⁺ concentrations, decreased apoptosis, and diminished ROS levels. In cartilage explants, EPA improved chondrocyte viability, minimized structural damage, and sustained higher Col-2a expression compared to the blunt trauma group. These results indicate that EPA effectively shields chondrocytes and cartilage explants from mechanical overload-induced damage by inhibiting Piezo1 activation and mitigating Ca²⁺ influx, apoptosis, and oxidative stress. The findings suggest that EPA supplementation could offer a promising strategy for preventing PTOA progression following acute cartilage injuries. Further research is warranted to assess the clinical applications of EPA and confirm its efficacy in larger animal models and human trials.

Cytokine priming enhances the antifibrotic effects of human adipose derived mesenchymal stromal cells conditioned medium

BackgroundFibrosis is a pathological scarring process characterized by persistent myofibroblast activation with excessive accumulation of extracellular matrix (ECM). Fibrotic disorders represent an increasing burden of disease-associated morbidity and mortality worldwide for which there are limited therapeutic options. Reversing fibrosis requires the elimination of myofibroblasts, remodeling of the ECM, and regeneration of functional tissue. Multipotent mesenchymal stromal cells (MSC) have antifibrotic properties mediated by secreted factors present in their conditioned medium (MSC-CM). However, there are no standardized in vitro assays to predict the antifibrotic effects of human MSC. As a result, we lack evidence on the effect of cytokine priming on MSC’s antifibrotic effects. We hypothesize that the MSC-CM promotes fibrosis resolution in vitro and that this effect is enhanced following MSC cytokine priming.MethodsWe compared the antifibrotic effects of resting versus interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) primed MSC-CM in four in vitro assays: prevention of fibroblast activation, myofibroblasts deactivation, ECM degradation and fibrosis resolution in lung explant cultures. Furthermore, we performed transcriptomic analysis of myofibroblasts treated or not with resting or primed MSC-CM and proteomic characterization of resting and primed MSC-CM.ResultsWe isolated MSC from adipose tissue of 8 donors, generated MSC-CM and tested each MSC-CM independently. We report that MSC-CM treatment prevented TGF-β induced fibroblast activation to a similar extent as nintedanib but, in contrast to nintedanib, MSC-CM reduced fibrogenic myofibroblasts (i.e. transcriptomic upregulation of apoptosis, senescence, and inflammatory pathways). These effects were larger when primed rather than resting MSC-CM were used. Priming increased the ability of MSC-CM to remodel the ECM, reducing its content of collagen I and fibronectin, and reduced the fibrotic load in TGF-β treated lung explant cultures. Priming increased the following antifibrotic proteins in MSC-CM: DKK1, MMP-1, MMP-3, follistatin and cathepsin S. Inhibition of DKK1 reduced the antifibrotic effects of MSC-CM.ConclusionsIn vitro, MSC-CM promote fibrosis resolution, an effect enhanced following MSC cytokine priming. Specifically, MSC-CM reduces fibrogenic myofibroblasts through apoptosis, senescence, and by enhancing ECM degradation. Future studies will establish the in vivo relevance of MSC priming to fibrosis resolution.

Immunomodulatory Effect of Vitamin D3 in Rats with Induced Osteoarthritis

Background: The (OA) caused by imbalance between anabolic and catabolic processes within the cartilage ,one of the effects of increased catabolic changes is presence of products of extracellular matrix degradation in the synovial fluid which lead to the joint microenvironment alteration which attempt. Aim of study: Evaluate the influence of induce osteoarthritis (OA) on knee joint and looking on (OA) effect as local immune response in addition to the possible role of vitamin (D3) as protective and repairing agent against (OA) complications. Methods: Total number of rats male (89) were used and divided into three groups, first group (control group) (19) rats, second group (OA induced) (35) rats injected with papain enzyme at dose of (10 mg), treated group (35) rats which firstly injected with papain enzyme at dose (10 mg) then after (2) weeks of injection, treated the rats with vitamin D. Results and Dicussion: Macroscopic observations revealed to cartilage surface erosion , fibrillation , hypertrophied condyles, degeneration. The rats knee joints that treated (2) weeks with vitamin (D3) post (OA) induced showed smooth, intact cartilage surface. Radiographic images indicated to narrowing joints cavity (space) at knee joint of (OA) rat model, destruction of epiphyseal plate, while the results related to (OA) rats treated with vitamin (D3) showed no osteophyte growth , the synovial cavity nearest to the normal, no defect. Conclusion: Vitamin (D) prevent the stability and life of chondrocytes which lead to cartilage protection and synthesis of (ECM) , and inhibite the inflammation resulted from cartilage damaged.

Regulatory effect and mechanism of CircSEC24A in IL-1β-induced osteoarthritis

Osteoarthritis (OA) is a chronic joint disease characterized by articular cartilage degeneration and damage. Increasing circular RNAs (circRNAs) have been identified to participate in the pathogenesis of OA. Hsa_circ_0128006 (also known as circSEC24) was reported as an upregulated circRNA in OA tissues, but its biological role and underlying mechanism in OA are still to be discussed. circSEC24A and NAMPT expression levels were upregulated, and miR-515-5p was reduced in OA cartilage tissues and IL-1β-treated CHON-001 cells. The absence of circSEC24A overturned IL-1β-induced suppression of cell viability and promotion of oxidative stress, apoptosis, extracellular matrix (ECM) degradation, and inflammation in CHON-001 cells. Mechanistically, circSEC24A acted as a molecular sponge for miR-515-5p to affect NAMPT expression. CircSEC24A knockdown could attenuate IL-1β-triggered CHON-001 cell injury partly via the miR-515-5p/NAMPT axis, providing new insight into the underlying application of circSEC24A in OA treatment.

Bridging the Gap: Advances and Challenges in Heart Regeneration from In Vitro to In Vivo Applications.

Cardiovascular diseases, particularly ischemic heart disease, area leading cause of morbidity and mortality worldwide. Myocardial infarction (MI) results in extensive cardiomyocyte loss, inflammation, extracellular matrix (ECM) degradation, fibrosis, and ultimately, adverse ventricular remodeling associated with impaired heart function. While heart transplantation is the only definitive treatment for end-stage heart failure, donor organ scarcity necessitates the development of alternative therapies. In such cases, methods to promote endogenous tissue regeneration by stimulating growth factor secretion and vascular formation alone are insufficient. Techniques for the creation and transplantation of viable tissues are therefore highly sought after. Approaches to cardiac regeneration range from stem cell injections to epicardial patches and interposition grafts. While numerous preclinical trials have demonstrated the positive effects of tissue transplantation on vasculogenesis and functional recovery, long-term graft survival in large animal models is rare. Adequate vascularization is essential for the survival of transplanted tissues, yet pre-formed microvasculature often fails to achieve sufficient engraftment. Recent studies report success in enhancing cell survival rates in vitro via tissue perfusion. However, the transition of these techniques to in vivo models remains challenging, especially in large animals. This review aims to highlight the evolution of cardiac patch and stem cell therapies for the treatment of cardiovascular disease, identify discrepancies between in vitro and in vivo studies, and discuss critical factors for establishing effective myocardial tissue regeneration in vivo.

Protective effects of alpinetin against interleukin-1β-exposed nucleus pulposus cells: Involvement of the TLR4/MyD88 pathway in a cellular model of intervertebral disc degeneration

Intervertebral disc degeneration (IDD) causes a variety of symptoms such as low back pain, disc herniation, and spinal stenosis, which can lead to high social and economic costs. Alpinetin has an anti-inflammatory potential, but its effect on IDD is unclear. Herein, we investigated the effect of alpinetin on IDD. To mimic an in vitro model of IDD, nucleus pulposus cells (NPCs) were exposed to interleukin 1β (IL-1β). The viability of NPCs was assessed by CCK-8 assay. The expression of Toll-like receptor 4 (TLR4), myeloid differentiation primary response protein 88 (MyD88), aggrecan, collagen-2, and matrix metalloproteinase-3 (MMP-3) was examined by qRT-PCR and western blotting. The protein levels of B cell lymphoma-2 (Bcl-2), Bcl-2-associated protein X (Bax), and cleaved caspase-3 were scrutinized by western blotting. The flow cytometry assay was performed to assess apoptosis of NPCs. The contents of inflammatory factors were examined by ELISA kits. Results showed that alpinetin repressed IL-1β-tempted activation of the TLR4/MyD88 pathway and apoptosis in NPCs. Alpinetin alleviated IL-1β-tempted inflammatory responses and oxidative stress in NPCs. Moreover, alpinetin lessened IL-1β-tempted extracellular matrix (ECM) degeneration in NPCs by enhancing the expression of aggrecan and collagen-2 and reducing the expression of MMP-3. The effects of alpinetin on IL-1β-exposed NPCs were neutralized by TLR4 upregulation. In conclusion, alpinetin repressed IL-1β-tempted apoptosis, inflammatory responses, oxidative stress, and ECM degradation in NPCs through the inactivation of the TLR4/MyD88 pathway.

The JNK signaling pathway in intervertebral disc degeneration.

Intervertebral disc degeneration (IDD) serves as the underlying pathology for various spinal degenerative conditions and is a primary contributor to low back pain (LBP). Recent studies have revealed a strong correlation between IDD and biological processes such as Programmed Cell Death (PCD), cellular senescence, inflammation, cell proliferation, extracellular matrix (ECM) degradation, and oxidative stress (OS). Of particular interest is the emerging evidence highlighting the significant involvement of the JNK signaling pathway in these fundamental biological processes of IDD. This paper explores the potential mechanisms through the JNK signaling pathway influences IDD in diverse ways. The objective of this article is to offer a fresh perspective and methodology for in-depth investigation into the pathogenesis of IDD by thoroughly examining the interplay between the JNK signaling pathway and IDD. Moreover, this paper summarizes the drugs and natural compounds that alleviate the progression of IDD by regulating the JNK signaling pathway. This paper aims to identify potential therapeutic targets and strategies for IDD treatment, providing valuable insights for clinical application.

Ginkgolide A enhances FoxO1 expression and reduces endoplasmic reticulum stress to mitigate osteoarthritis in mice

This study aimed to investigate the effects of Ginkgolide A (GA) on chondrocytes under oxidative stress and to elucidate its potential molecular mechanisms. Using a destabilization of the medial meniscus (DMM) model in mice and an in vitro osteoarthritis (OA) model induced by tert-butyl hydroperoxide (TBHP) in chondrocytes, we validated the therapeutic efficacy and underlying mechanisms of GA. Potential OA targets of GA were identified through network pharmacology, Gene Ontology (GO) analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Further exploration into the effects on endoplasmic reticulum stress (ERS), apoptosis, extracellular matrix (ECM) degradation, and Forkhead Box O1 (FoxO1) related pathways was conducted using Western blotting, immunofluorescence, TUNEL staining, flow cytometry, X-ray, micro-computed tomography (Micro-CT) analysis, and histological staining. The results demonstrated that GA upregulated FoxO1 expression and inhibited ERS-related signaling pathways, thereby reducing apoptosis and ECM degradation. In conclusion, GA significantly alleviated OA symptoms both in vitro and in vivo, suggesting its potential as a therapeutic agent for OA.

Markers of extracellular matrix degradation and inflammasome activation are associated with carotid plaques in virally suppressed people with HIV in Botswana.

HIV is associated with increased risk of cardiovascular disease. We investigated soluble markers of extracellular matrix (ECM) remodeling and inflammation in relation to presence of carotid plaques in a well-characterized adult cross-sectional study of people with HIV (PWH) and matched people without HIV in Botswana. Using enzyme immunoassays we analyzed plasma ECM remodeling mediators including Galectin-3 (GAL-3), Cystatin B (CysB) and Growth/differentiation factor 15 (GDF-15) and the inflammatory marker IL-18 in 196 without HIV and 197 PWH of which 36 were ART-naïve. We found i) PWH had higher plasma levels of the ECM markers GAL-3 and CysB and the NLRP3 inflammasome activation marker IL-18, mainly in ART naïve participants, ii) PWH on ART had markedly higher GDF-15, associated with use of first generation nucleoside analogs; iii) high levels of CysB and IL-18 correlated with presence of carotid plaques. In PWH, high levels of CysB and IL-18 were associated with the presence of carotid plaques. For IL-18 this was observed in the study population as a whole, while the association for CysB was restricted to PWH.

Inhibition of ATP1V6G3 prompts hepatic stellate cell senescence with reducing ECM by activating Notch1 pathway to alleviate hepatic fibrosis

Liver fibrosis is characterized by an excessive reparative response to various etiological factors, with the activated hepatic stellate cells (aHSCs) leading to extracellular matrix (ECM) accumulation. Senescence is a stable growth arrest, and the senescence of aHSCs is associated with the degradation of ECM and the regression of hepatic fibrosis, making it a promising approach for managing hepatic fibrosis. The role and specific mechanisms by which V-Type Proton ATPase Subunit G 3 (ATP6V1G3) influences senescence in activated HSCs during liver fibrosis remain unclear. Our preliminary results reveal upregulation of ATP6V1G3 in both human fibrotic livers and murine liver fibrosis models. Additionally, ATP6V1G3 inhibition induced senescence in aHSCs in vitro. Moreover, suppressing Notch1 reversed the senescence caused by ATP6V1G3 inhibition in HSCs. Thus, targeting ATP6V1G3, which appears to drive HSCs senescence through the Notch1 pathway, emerges as a potential therapeutic strategy for hepatic fibrosis.

Lipoxin A4 modulates the PKA/CREB and NF-κB signaling pathway to mitigate chondrocyte catabolism and apoptosis in temporomandibular joint osteoarthritis

Temporomandibular joint osteoarthritis (TMJ-OA) is characterized by the degradation of the extracellular matrix (ECM) in cartilage and the apoptosis of chondrocytes, which is caused by inflammation and disruptions of chondrocyte metabolism and inflammation. Lipoxin A4 (LXA4), a specialized pro-resolving mediator, has been shown to inhibit inflammation and regulate the balance between ECM synthesis and degradation. However, the therapeutic effects of LXA4 on TMJ-OA and its underlying mechanisms remain unclear. Interleukin-1 beta (IL-1β)-induced chondrocyte and surgically induced TMJ-OA rat models were established in this study. The viability of chondrocytes treated with LXA4 was evaluated with the cell counting kit-8 (CCK-8) assay, while protein levels were assessed by western blot analysis, and the apoptosis rate was evaluated with terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labelling (TUNEL) staining. Histological analysis was conducted to evaluate the impact of LXA4 on cartilage degradation in TMJ-OA rat models. In vitro, the qRT-PCR and western blot analysis demonstrated that LXA4 facilitated the upregulation of collagen proteins (Collagen II) and decreased expression of matrix metalloproteinases (MMP-3, and MMP-13) associated with ECM modulation. LXA4 enhanced the TMJ-OA chondrocyte viability and decreased apoptotic rate. In vivo, histology and immunohistochemistry (IHC) analysis revealed that intraperitoneal injection of LXA4 contributed to the amelioration of chondrocyte injuries and deceleration of TMJ-OA. Transcriptomic sequencing revealed that cAMP signaling pathway was up-regulated and NF-κB signaling pathway was down-regulated in LXA4 treated group. LXA4 inhibited the phosphorylation of P65 and inhibitor of nuclear factor kappa B (IκBα) proteins while enhancing the phosphorylation PKA and CREB. This study demonstrates the potential of LXA4 as a therapeutic agent for suppressing chondrocyte catabolism and apoptosis by increasing PKA/CREB activity and decreasing NF-κB signaling.

Effects of electroacupuncture at "Jiaji" (EX-B 2) on extracellular matrix of chondrocytes and inflammatory reaction in rabbits with Modic changes of cartilage endplate

To observe the effects of electroacupuncture (EA) at "Jiaji" (EX-B 2) on extracellular matrix (ECM) of chondrocytes and inflammatory reaction in rabbits with Modic changes (MC) of cartilage endplate, and to explore the mechanism of EA in treating MC of endplate cartilage. Eighteen male New Zealand white rabbits were randomly divided into a sham operation group, a model group and an EA group, 6 rabbits in each group. Based on the autoimmune theory, MC model was established by embedding autogenous nucleus pulposus in the rabbits of the model group and the EA group, based on autoimmunity. After successful modeling, EA was applied at bilateral "Jiaji" (EX-B 2) of L5 and L6 in the EA group, with disperse-dense wave, 2 Hz/15 Hz in frequency and 1 mA in current intensity, 20 min a time, once a day, 1-day interval was taken after continuous 6-day intervention, for 4 weeks totally. Before and after modeling, as well as before and after intervention, the comprehensive response score was observed. After modeling and intervention, magnetic resonance imaging (MRI) was used to observe the signal intensity of intervertebral disc and cartilage endplate. After intervention, the morphology of chondrocytes of cartilage endplate was observed by HE staining; the positive expression of a disintegrin and metalloproteinase with thrombospondin motif-5 (ADAMTS5) and Aggrecan in the cartilage endplate was detected by immunohistochemistry; the levels of inflammatory factors i.e. interleukin-1β (1L-1β) and tumor necrosis factor-α (TNF-α) in the cartilage endplate were detected by ELISA; the protein expression of ADAMTS5, Aggrecan, matrix metalloproteinase-13 (MMP-13), IL-1β and TNF-α in the cartilage endplate was detected by Western blot. Compared with the sham operation group, in the model group, the comprehensive response score was decreased (P<0.01); L5/L6 intervertebral disc and the cancellous bones of endplate vertebral body showed low signal and unclear boundary; the chondrocytes of the cartilage endplate increased significantly, the cells were enlarged and hypertrophic, and the nuclei were wrinkled and clustered; the positive expression of ADAMTS5 as well as the levels of IL-1β and TNF-α were increased (P<0.01), while the positive expression of Aggrecan was decreased (P<0.01) in the cartilage endplate; the protein expression of ADAMTS5, MMP-13, IL-1β and TNF-α was increased (P<0.01), while that of Aggrecan was decreased (P<0.01) in the cartilage endplate. Compared with the model group, in the EA group, the comprehensive response score was increased (P<0.01); the signal of L5/L6 intervertebral disc and the cancellous bones of endplate vertebral body was enhanced; the chondrocytes of the cartilage endplate were reduced, the nuclei were slightly crumpled and scattered; the positive expression of ADAMTS5 as well as the levels of IL-1β and TNF-α were decreased (P<0.05, P<0.01), while the positive expression of Aggrecan was increased (P<0.01) in the cartilage endplate; the protein expression of ADAMTS5, MMP-13, IL-1β and TNF-α was decreased (P<0.05, P<0.01), while that of Aggrecan was increased (P<0.05) in the cartilage endplate. EA at "Jiaji" (EX-B 2) can delay the MC of cartilage endplate. The mechanism may be related to inhibiting the degradation of ECM of chondrocytes and the secretion of inflammatory factors, and repairing the degeneration of endplate cartilage.

Genetics and pathogenesis of scoliosis

BackgroundScoliosis is defined as a lateral spine curvature of at least 10° with vertebral rotation, as seen on a posterior-anterior radiograph, often accompanied by reduced thoracic kyphosis. Scoliosis affects all age groups: idiopathic scoliosis is the most common spinal disorder in children and adolescents, while adult degenerative scoliosis typically affects individuals over fifty. In the United States, approximately 3 million new cases of scoliosis are diagnosed annually, with a predicted increase in part due to global aging. Despite its prevalence, the etiopathogenesis of scoliosis remains unclear. MethodsThis comprehensive review analyzes the literature on the etiopathogenetic evidence for both idiopathic and adult degenerative scoliosis. PubMed and Google Scholar databases were searched for studies on the genetic factors and etiopathogenetic mechanisms of scoliosis development and progression, with the search limited to articles in English. ResultsFor idiopathic scoliosis, genetic factors are categorized into three groups: genes associated with susceptibility, disease progression, and both. We identify gene groups related to different biological processes and explore multifaceted pathogenesis of idiopathic scoliosis, including evolutionary adaptations to bipedalism and developmental and homeostatic spinal aberrations. For adult degenerative scoliosis, we segregate genetic and pathogenic evidence into categories of angiogenesis and inflammation, extracellular matrix degradation, neural associations, and hormonal influences. Finally, we compare findings in idiopathic scoliosis and adult degenerative scoliosis, discuss current limitations in scoliosis research, propose a new model for scoliosis etiopathogenesis, and highlight promising areas for future studies. ConclusionScoliosis is a complex, multifaceted disease with largely enigmatic origins and mechanisms of progression, keeping it under continuous scientific scrutiny.

Targeting Fascin1 maintains chondrocytes phenotype and attenuates osteoarthritis development

Osteoarthritis (OA) is the most common form of arthritic disease, and phenotypic modification of chondrocytes is an important mechanism that contributes to the loss of cartilage homeostasis. This study identified that Fascin actin-bundling protein 1 (FSCN1) plays a pivotal role in regulating chondrocytes phenotype and maintaining cartilage homeostasis. Proteome-wide screening revealed markedly upregulated FSCN1 protein expression in human OA cartilage. FSCN1 accumulation was confirmed in the superficial layer of OA cartilage from humans and mice, primarily in dedifferentiated-like chondrocytes, associated with enhanced actin stress fiber formation and upregulated type I and III collagens. FSCN1-inducible knockout mice exhibited delayed cartilage degeneration following experimental OA surgery. Mechanistically, FSCN1 promoted actin polymerization and disrupted the inhibition of Decorin on TGF-β1, leading to excessive TGF-β1 production and ALK1/Smad1/5 signaling activation, thus, accelerated chondrocyte dedifferentiation. Intra-articular injection of FSCN1-overexpressing adeno-associated virus exacerbated OA progression in mice, which was mitigated by an ALK1 inhibitor. Moreover, FSCN1 inhibitor NP-G2-044 effectively reduced extracellular matrix degradation in OA mice, cultured human OA chondrocytes, and cartilage explants by suppressing ALK1/Smad1/5 signaling. These findings suggest that targeting FSCN1 represents a promising therapeutic approach for OA.

Collagen II enrichment through scAAV6-RNAi-mediated inhibition of matrix-metalloproteinases 3 and 13 in degenerative nucleus-pulposus cells degenerative disc disease and biological treatment strategies.

Intervertebral disc (IVD) degeneration damaging the extracellular matrix (ECM) of IVDs is the main cause of spine-associated disorders. Degenerative disc disease (DDD) is a multifaceted disorder, where environmental factors, inflammatory cytokines and catabolic enzymes act together. DDD starts typically due to imbalance between ECM biosynthesis and degradation within IVDs, especially through unbalanced degradation of aggrecan and collagen II in nucleus pulposus (NP). Current treatment approaches are primarily based on conservative or surgical therapies, which are insufficient for biological regeneration. The disintegrins and metalloproteinases with thrombospondin motifs (ADAMTSs) and matrix metalloproteinases (MMPs) are the key proteolytic enzymes for degradation of aggrecan and collagens. Previously, high expression levels of ADAMTS4, ADAMTS5, MMP3 and MMP13, which are accompanied with low levels of aggrecan and collagen II, were demonstrated in degenerative human NP cells. Moreover, self-complementary adeno-associated virus type 6 (scAAV6) mediated inhibitions of ADAMTS4 and ADAMTS5 by RNA-interference (RNAi) could specifically enhance aggrecan level. Thus, MMPs are apparently the main degrading enzymes of collagen II in NP. Furthermore, scAAV6-mediated inhibitions of MMP3 and MMP13 have not yet been investigated. Therefore, we attempted to enhance the level of collagen II in degenerative NP cells by scAAV6-RNAi-mediated inhibitions of MMP3 and MMP13. MRI was used to determine preoperative grading of IVD degeneration in patients. After isolation and culturing of NP cells, cells were transduced with scAAV6-shRNAs targeting MMP3 or MMP13; and analysed by fluorescence microscopy, FACS, MTT assay, RT-qPCR, ELISA and western blotting. scAAV6-shRNRs have no impact on cell viability and proliferation, despite high transduction efficiencies (98.6%) and transduction units (1383 TU/Cell). Combined knockdown of MMP3 (92.8%) and MMP13 (90.9%) resulted in highest enhancement of collagen II (143.2%), whereby treatment effects were significant over 56days (p < 0.001). Conclusively, scAAV6-RNAi-mediated inhibitions of MMP3 and MMP13 help to progress less immunogenic and enduring biological treatments in DDD.

Isoquercetin Ameliorates Osteoarthritis via Nrf2/NF-κB Axis: An InVitro and InVivo Study.

Osteoarthritis (OA) is a progressive joint disease characterized by extracellular matrix (ECM) degradation and inflammation, which is involved with pathological microenvironmental alterations induced by damaged chondrocytes. However, current therapies are not effective in alleviating the progression of OA. Isoquercetin is a natural flavonoid glycoside compound that has various pharmacological effects including anticancer, anti-diabetes and blood lipid regulation. Previous evidence suggests that isoquercetin has anti-inflammatory properties in various diseases, but its effect on OA has not been investigated yet. In this study, through western bolt, qRT-PCR and ELISA, it was found that isoquercetin could reduce the increase of ADAMTS5, MMP13, COX-2, iNOS and IL-6 induced by IL-1β, suggesting that isoquercetin could inhibit the inflammation and ECM degradation of chondrocytes. Through nuclear-plasma separation technique, western blot and immunocytochemistry, it can be found that Nrf2 and NF-κB pathways are activated in this process, and isoquercetin may rely on this process to play its protective role. Invivo, the results of X-ray and SO staining show that intra-articular injection of isoquercetin reduces the degradation of cartilage in the mouse OA model. In conclusion, the present work suggests that isoquercetin may benefit chondrocytes by regulating the Nrf2/NF-κB signaling axis, which supports isoquercetin as a potential drug for the treatment of OA.