Temporomandibular joint osteoarthritis (TMJ OA) is a common and heterogeneous disease that causes painful and progressive joint degeneration, which restricts daily activities, including talking and ...chewing. Long noncoding RNAs (lncRNAs) are an important class of genes involved in various physiological and pathological functions, including osteoarthritis (OA).The present study aimed to identify the lncRNAs that are important in TMJ OA and their potential functions. Here, we found that HOTAIR was significantly upregulated in the synovial fluid of TMJ OA patients compared with that of normal controls. Increased HOTAIR was similarly observed in the synovial fluid of TMJ OA rabbits as compared to control rabbits. Furthermore, in interleukin-1β (IL-1β)-induced TMJ OA in vitro model (primary rabbit condylar chondrocytes), the expressions of matrix metalloproteinase (MMP)-1, MMP3, MMP9 and HOTAIR were all dramatically increased. Most importantly, knockdown of HOTAIR in IL-1β-induced TMJ OA in vitro model could not only reverse the IL-1β-stimulated expressions of MMP1, MMP3 and MMP9, but also significantly decrease the apoptosis rate induced by IL-1β in primary rabbit condylar chondrocytes. Our data provides new insight into the mechanisms of chondrocytes destruction in TMJ OA.
•Our data suggests that HOTAIR possess potential value in the diagnosis and treatment of TMJ OA.•The underlying molecular mechanisms associated with TMJ OA is partly elaborated.•The effective clinical diagnosis and treatment using HOTAIR need ongoing exploration in future.
Interleukin-1β (IL-1β) is a pro-inflammatory cytokine that plays a key role in the pathogenesis of osteoarthritis (OA). Growth factors (GFs) capable of antagonizing the catabolic actions of cytokines ...may have therapeutic potential in the treatment of OA. Herein, we investigated the potential synergistic effects of insulin-like growth factor (IGF-1) and platelet-derived growth factor (PDGF-bb) on different mechanisms participating in IL-1β-induced activation of nuclear transcription factor-κB (NF-κB) and apoptosis in chondrocytes.
Primary chondrocytes were treated with IL-1β to induce dedifferentiation and co-treated with either IGF-1 or/and PDGF-bb and evaluated by immunoblotting and electron microscopy.
Pretreatment of chondrocytes with IGF-1 or/and PDGF-bb suppressed IL-1β-induced NF-κB activation via inhibition of IκB-α kinase. Inhibition of IκB-α kinase by GFs led to the suppression of IκB-α phosphorylation and degradation, p65 nuclear translocation and NF-κB-regulated gene products involved in inflammation and cartilage degradation (COX-2, MMPs) and apoptosis (caspase-3). GFs or BMS-345541 (specific inhibitor of the IKK) reversed the IL-1β-induced down-regulation of collagen type II, cartilage specific proteoglycans, β1-integrin, Shc, activated MAPKinase, Sox-9 and up-regulation of active caspase-3. Furthermore, the inhibitory effects of IGF-1 or/and PDGF-bb on IL-1β-induced NF-κB activation were sensitive to inhibitors of Src (PP1), PI-3K (wortmannin) and Akt (SH-5), suggesting that the pathway consisting of non-receptor tyrosine kinase (Src), phosphatidylinositol 3-kinase and protein kinase B must be involved in IL-1β signaling.
The results presented suggest that IGF-1 and PDGF-bb are potent inhibitors of IL-1β-mediated activation of NF-κB and apoptosis in chondrocytes, may be mediated in part through suppression of Src/PI-3K/AKT pathway, which may contribute to their anti-inflammatory effects.
Purpose
Traumatic lesions of articular cartilage represent a crucial risk factor for osteoarthritis. Even if several strategies exist to treat such damages, the optimal solution has not yet been ...found. A new strategy represents the scaffold-free spheroid-based autologous chondrocyte transplantation. In this method, spheroids of chondrocytes are synthesized after chondrocyte isolation and expansion, followed by the implantation in a second intervention.
Methods
Fine Jamshidi-needle biopsies from five patients (one from each patient, Ø 2 mm) treated with a spheroid-based autologous chondrocyte implantation (ACI) after traumatic lesions of the articular cartilage of the knee were analysed histologically and immunohistologically for collagen II, collagen X and aggrecan expression. The indication for a second look arthroscopy was given by arthrofibrosis or meniscus-lesions, respectively. The time between ACI and second-look arthroscopy ranged between 6 and 16 months.
Results
In all patients, the histological examinations revealed an avascular cartilage tissue with a homogenic extracellular matrix. The subchondral bone neither showed bleeding, necrosis nor hypertrophy. A homogenous alcian blue staining indicated high amounts of mucopolysaccharides and glycosaminoglycans. Collagen II staining was highly positive, whereas collagen X staining was negative in every patient, ruling out hypertrophic chondrocyte differentiation. In addition, intense aggrecan staining indicated a strong expression of this extracellular matrix component.
Conclusion
The present case series represents the first histological and immunohistological analyses of spheroid-based ACI in humans. Spheroid-based ACI revealed excellent histological results regarding the regeneration of hyaline articular cartilage. These results indicate that spheroid based ACI is a promising strategy for treating traumatic lesions of the articular cartilage of the knee.
Berberine, a plant alkaloid used in Chinese medicine, has broad cell‐protective functions in a variety of cell lines. Chondrocyte apoptosis contributes to the pathogenesis of cartilage degeneration ...in osteoarthritis (OA). However, little is known about the effect and underlying mechanism of berberine on OA chondrocytes. Here, we assessed the effects of berberine on cartilage degeneration in interleukin‐1β (IL‐1β)‐stimulated rat chondrocytes and in a rat model of OA. The results of an MTT assay and western blotting analysis showed that berberine attenuated the inhibitory effect of IL‐1β on the cell viability and proliferating cell nuclear antigen expression in rat chondrocytes. Furthermore, berberine activated Akt, which triggered p70S6K/S6 pathway and up‐regulated the levels of aggrecan and Col II expression in IL‐1β‐stimulated rat chondrocytes. In addition, berberine increased the level of proteoglycans in cartilage matrix and the thickness of articular cartilage, with the elevated levels of Col II, p‐Akt and p‐S6 expression in a rat OA model, as demonstrated by histopathological and immunohistochemistry techniques. The data thus strongly suggest that berberine may ameliorate cartilage degeneration from OA by promoting cell survival and matrix production of chondrocytes, which was partly attributed to the activation of Akt in IL‐1β‐stimulated articular chondrocytes and in a rat OA model. The resultant chondroprotective effects indicate that berberine merits consideration as a therapeutic agent in OA.
Autologous chondrocyte implantation (ACI) is a cell therapy for the treatment of focal cartilage defects. The ACI product that is currently approved for use in the European Union (EU) consists of ...spheroids of autologous matrix-associated chondrocytes. These spheroids are spherical aggregates of ex vivo expanded human autologous chondrocytes and their self-synthesized extracellular matrix. The aim is to provide an overview of the preclinical and nonclinical studies that have been performed to ensure reproducible quality, safety, and efficacy of the cell therapy, and to evaluate the clinical data on ACI with spheroids. A systematic review was performed to include all English publications on self-aggregated spheroids of chondrocytes cultured in autologous serum without other supplements. A total of 20 publications were included, 7 pre- and nonclinical and 13 clinical research publications. The pre- and nonclinical research publications describe the development from concept to in vivo efficacy and quality- and safety-related aspects such as biodistribution, tumorigenicity, genetic stability, and potency. The evaluation of clinical research shows short- to mid-term safety and efficacy for the ACI with spheroid-based treatment of cartilage defects in both randomized clinical trials with selected patients, as well as in routine treatment providing real-world data in more complex patients.
Oxidative stress has been implicated in the pathogenesis of osteoarthritis and has become an important therapeutic target. Investigations of various antioxidant supplements, reactive oxidative ...species (ROS) pathway mediators, and free radical scavengers for treating osteoarthritis have demonstrated common disadvantages including poor bioavailability and stability, as well as rapid joint clearance or release profiles from delivery vehicles. Moreover, these therapies do not target cartilage, which irreversibly degenerates in the presence of oxidative stress. The goal of this study was to engineer a nanoparticle system capable of sustained retention in the joint space, localization to cartilage, and mitigation of oxidative stress. Towards this goal, ROS scavenging manganese dioxide nanoparticles with physicochemical properties (less than 20 nm and cationic) that facilitate their uptake into cartilage were developed and characterized. These particles penetrated through the depth of cartilage explants and were found both in the extracellular matrix as well as intracellularly within the resident chondrocytes. Furthermore, the particles demonstrated chondroprotection of cytokine-challenged cartilage explants by reducing the loss of glycosaminoglycans and release of nitric oxide. Quantitative PCR analysis revealed that the particles mitigated impacts of oxidative stress related genes in cytokine-challenged chondrocytes. When injected intra-articularly into rats, the particles persisted in the joint space over one week, with 75% of the initial signal remaining in the joint. Biodistribution and histological analysis revealed accumulation of particles at the chondral surfaces and colocalization of the particles with the lacunae of chondrocytes. The results suggest that the manganese dioxide nanoparticles could be a promising approach for the chondroprotection of osteoarthritic cartilage.
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Abnormal expression of KDM6A and SOX9 is a key factor in the pathogenesis of osteoarthritis (OA). Cellular treatments of OA with articular cartilage chondrocytes (ACCs) and bone marrow mesenchymal ...stem cells (BMSCs) are promising, but their underlying mechanisms remain to be explored. The pellet size, weight and sulfated glycosaminoglycan/DNA content of ACCs were measured to evaluate the effect of BMSCs on the chondrogenic differentiation of SCCs. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay was used to analyze the proliferation of ACCs cultured along or cocultured with BMSCs. Quantitative polymerase chain reaction (qPCR) was performed to evaluate the messenger RNA expression of KDM6A, SOX9, type2 collagen, and Aggrecan in ACCs and OA rats. Western blot and immunohistochemistry were performed to analyze the expression of KDM6A and SOX9 proteins. Bisulfite sequencing PCR was performed to assess the DNA methylation level of the SOX9 promoter. Flow cytometry was used to evaluate the apoptotic status of ACCs. The chondrogenic differentiation of ACCs was significantly enhanced by coculturing with BMSCs, especially under a hypoxic condition. The expression of KDM6A, SOX9, type2 collagen, and Aggrecan was remarkably elevated in ACCs cocultured with BMSCs. Also, the DNA methylation of SOX9 promoter was decreased in ACCs cocultured with BMSCs, along with notably reduced apoptosis. Moreover, ACCs cocultured with BMSCs could repair cartilage lesions and prevent the abnormal expression of KDM6A, SOX9, type2 collagen, and Aggrecan in OA rats. In this study, we cocultured ACCs with BMSCs and used them to treat OA rats. Our findings presented a mechanistic basis for explaining the therapeutic effect of BMSCs on OA treatment.
Our data suggested that hypoxia improved the differentiation and proliferation of bone marrow mesenchymal stem cells (BMSCs) by promoting KDM6A expression and activating the SOX9 signaling pathway. This is a novel mechanism underlying the differentiation of BMSCs that highlights a promising future for osteoarthritis (OA) treatment.
Mechanical loading of joints plays a critical role in maintaining the health and function of articular cartilage. The mechanism(s) of chondrocyte mechanotransduction are not fully understood, but ...could provide important insights into new physical or pharmacologic therapies for joint diseases. Transient receptor potential vanilloid 4 (TRPV4), a Ca ²⁺-permeable osmomechano-TRP channel, is highly expressed in articular chondrocytes, and loss of TRPV4 function is associated with joint arthropathy and osteoarthritis. The goal of this study was to examine the hypothesis that TRPV4 transduces dynamic compressive loading in articular chondrocytes. We first confirmed the presence of physically induced, TRPV4-dependent intracellular Ca ²⁺ signaling in agarose-embedded chondrocytes, and then used this model system to study the role of TRPV4 in regulating the response of chondrocytes to dynamic compression. Inhibition of TRPV4 during dynamic loading prevented acute, mechanically mediated regulation of proanabolic and anticatabolic genes, and furthermore, blocked the loading-induced enhancement of matrix accumulation and mechanical properties. Furthermore, chemical activation of TRPV4 by the agonist GSK1016790A in the absence of mechanical loading similarly enhanced anabolic and suppressed catabolic gene expression, and potently increased matrix biosynthesis and construct mechanical properties. These findings support the hypothesis that TRPV4-mediated Ca ²⁺ signaling plays a central role in the transduction of mechanical signals to support cartilage extracellular matrix maintenance and joint health. Moreover, these insights raise the possibility of therapeutically targeting TRPV4-mediated mechanotransduction for the treatment of diseases such as osteoarthritis, as well as to enhance matrix formation and functional properties of tissue-engineered cartilage as an alternative to bioreactor-based mechanical stimulation.
Abnormal post-transcriptional modulations in inflammatory genes by microRNAs (miRNAs) play a crucial role in human disorders including arthritis. In this study, we determined the effect of ...hsa-miR-125b-5p on interleukin (IL)-1β induced inflammatory genes in human osteoarthritic (OA) chondrocytes. Bioinformatics algorithms showed 3'untranslated region (3'UTR) of TRAF6 mRNA (NM_004620.3) has perfectly matched 'seed-sequence' for hsa-miR-125b-5p. Treatment of cells with IL-1β up-regulates TRAF6 mRNA and down-regulates hsa-miR-125b-5p expression. This negative correlation between TRAF6 and hsa-miR-125b-5p was verified by transfection with miR-125b mimic (pre-miR-125b). Moreover, transfection with miR-125b mimic caused marked inhibition of IL-1β-induced phosphorylation of p38-MAPK, JNK-MAPKs and ERK-MAPKs and also suppressed the nuclear levels of NF-κBp50, NF-κBp65 and inhibited the activation of IκBα. Furthermore, transfected chondrocytes with miR-125b mimic in the presence of IL-1β also showed marked inhibition in the secretion of several proinflammatory cytokines, chemokines and growth factors including IL-6, IL-8, INF-γ, TGF-β1, IGFBP-1 and PGDF-BB. Importantly, this transfection also significantly inhibited IL-1β- induced MMP-13 expression/production. In short, this study concludes that hsa-miR-125b-5p acts as a negative co-regulator of inflammatory genes including MMP-13 via targeting TRAF6/MAPKs/NF-κB pathway in human OA chondrocytes.
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