Inflammation and epigenetic regulation in osteoarthritis

Gene expression profiling of primary fibrochondrocyte cultures in traumatic and degenerative meniscus lesions

PURPOSE

This study aimed to investigate how fibroblastic and chondrocytic properties of human meniscal fibrochondrocytes are affected in culture conditions according to the type of meniscal pathology and localization, and to provide basic information for tissue-engineering studies.

METHODS

Primary fibrochondrocyte cultures were prepared from meniscus samples of patients who had either traumatic tear or degeneration due to osteoarthritis. Cultures were compared in terms of mRNA expression levels of COL1A1, COL2A1, COMP1, HIF1A, HIF2A, and SOX9 and secreted total collagen and sulfated sGAG levels according to the type of meniscal pathology, anatomical localization, and the number of subcultures.

RESULTS

mRNA expression levels of COL1A1, COMP1, HIF1A, HIF2A, and SOX9 were found to be increased in subsequent subcultures in all specimens. COL1A1 mRNA expression levels of both lateral and medial menisci of patients with traumatic tear were significantly higher than in patients with degenerative pathology, indicating a more fibroblastic character. P1 subculture of lateral and P3 or further subculture of medial meniscus showed more fibroblastic characteristics in patients with degenerative pathology. Furthermore, in patients with degenerative pathology, the subcultures of the lateral meniscus (especially on the inner part) presented more chondrocytic characteristics than did those of medial meniscus.

CONCLUSIONS

The mRNA expression levels of the cultures showed significant differences according to the anatomical localization and pathology of the meniscus, indicating distinct chondrocytic and fibroblastic features. This fundamental knowledge would help researchers to choose more efficient cell sources for cell-seeding of a meniscus scaffold, and to generate a construct resembling the original meniscus tissue.

Knockdown of TRIM8 Attenuates IL-1β-induced Inflammatory Response in Osteoarthritis Chondrocytes Through the Inactivation of NF-κB Pathway

Osteoarthritis (OA) is a degenerative joint disease associated with inflammatory response. Tripartite motif 8 (TRIM8) is a member of TRIM family that has been found to regulate inflammation. The present study was aimed to evaluate the role of TRIM8 in OA chondrocytes. Our results showed that TRIM8 expression was significantly increased in interleukin 1 beta (IL-1β)-stimulated OA chondrocytes. To knock down the TRIM8 expression in chondrocytes, the chondrocytes were transfected with si-TRIM8. Knockdown of TRIM8 attenuated IL-1β-induced production of inflammatory mediators including nitric oxide and prostaglandin E₂. The increased expression levels of inducible nitric oxide synthase and cyclooxygenase-2 in IL-1β-induced chondrocytes were suppressed by TRIM8 knockdown. The IL-1β-induced production of proinflammatory cytokines including TNF-α and IL-6 was significantly decreased after transfection with si-TRIM8. Besides, knockdown of TRIM8 mitigated the IL-1β-induced decrease in aggrecan and collagen-II proteins expression and increase in matrix-degrading enzymes in chondrocytes. Furthermore, TRIM8 knockdown prevented IL-1β-induced nuclear factor kappa B (NF-κB) activation in chondrocytes. Taken together, these findings indicated that knockdown of TRIM8 attenuates IL-1β-induced inflammatory response in OA chondrocytes through the inactivation of NF-κB pathway. Thus, targeting TRIM8 might provide therapeutic treatment for OA.

Platelet-rich plasma inhibits Adriamycin-induced inflammation via blocking the NF-κB pathway in articular chondrocytes

Background

Previous studies showed that doxorubicin could lead to osteoarthritis (OA) by inducing chondrocyte inflammation and apoptosis. Besides, it is reported that platelet-rich plasma (PRP) could suppress the activation of inflammatory NF-κB signaling. Here, we aimed to determine whether PRP was able to exert a protective effect against doxorubicin-induced chondrocyte damages.

Methods

To determine whether PRP protects chondrocytes against destabilization of the medial meniscus (DMM)-induced osteoarthritis, mice were treated with PRP and doxorubicin, and the cartilage destruction was observed through Safranin O-fast green staining and osteoarthritis scoring. ELISA assay was used to check the release of TNF-α and ILs. In vitro, we treated chondrocytes with doxorubicin and PRP; CCK-8 was used to measure cell viability. Western blot, real-time PCR, and ELISA were applied to check apoptosis-related signaling and inflammation-associated factors.

Results

The results from the mouse model suggested that PRP attenuated doxorubicin-induced cartilage destruction in vivo. Doxorubicin promoted chondrocyte apoptosis while PRP ameliorated this damage. PRP inhibited doxorubicin-induced dysregulation of cell matrix-related factors, including SOX9, Col2A1, Col10A1, and Aggrecan, reduced protein levels of doxorubicin-induced inflammatory markers, COX-2, and iNOS, and blocked doxorubicin-induced phosphorylation of IκB and NF-κB in articular chondrocytes.

Conclusions

PRP improved doxorubicin-induced damage on chondrocytes. This research might provide a new theoretical basis for the clinical treatment of osteoarthritis caused by doxorubicin.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00314-2.

MiR-24-3p attenuates IL-1β-induced chondrocyte injury associated with osteoarthritis by targeting BCL2L12

Background

MiR-24-3p has been reported to be involved in an osteoarthritis (OA)-resembling environment. However, the functional role and underlying mechanism of miR-24-3p in chondrocyte injury associated with OA remains unknown.

Methods

The expression of miR-24-3p was determined using reverse transcription quantitative PCR analysis in OA cases and control patients, as well as IL-1β-stimulated chondrocyte cell line CHON-001. The cell viability was analyzed by CCK-8 assay. Apoptosis status was assessed by caspase-3 activity detection. The pro-inflammatory cytokines (TNF-α and IL-18) were determined using ELISA assay. The association between miR-24-3p and B cell leukemia 2-like 12 (BCL2L12) was confirmed by luciferase reporter assay.

Results

We first observed that miR-24-3p expression level was lower in the OA cases than in the control patients and IL-1β decreased the expression of miR-24-3p in the chondrocyte CHON-001. Functionally, overexpression of miR-24-3p significantly attenuated IL-1β-induced chondrocyte injury, as reflected by increased cell viability, decreased caspase-3 activity, and pro-inflammatory cytokines (TNF-α and IL-18). Western blot analysis showed that overexpression of miR-24-3p weakened IL-1β-induced cartilage degradation, as reflected by reduction of MMP13 (Matrix Metalloproteinase-13) and ADAMTS5 (a disintegrin and metalloproteinase with thrombospondin motifs-5) protein expression, as well as markedly elevation of COL2A1 (collagen type II). Importantly, BCL2L12 was demonstrated to be a target of miR-24-3p. BCL2L12 knockdown imitated, while overexpression significantly abrogated the protective effects of miR-24-3p against IL-1β-induced chondrocyte injury.

Conclusions

In conclusion, our work provides important insight into targeting miR-24-3p/BCL2L12 axis in OA therapy.

Pollution, Inflammation, and Vaccines: A Complex Crosstalk

The importance of pollution in determining human health is becoming increasingly clear, also given the dramatic consequences it has had on recent geopolitical events. Yet, the consequences of contamination are not always straightforward. In this paper, we will discuss the effects of different pollutants on different aspects of human health, in particular on the immune system and inflammation. Different environmental pollutants can have different effects on the immune system, which can then promote complex pathologies, such as autoimmune disorders and cancer. The interaction with the microbiota also further helps to determine the consequences of contamination on wellbeing. The pollution can affect vaccination efficacy, given the widespread effects of vaccination on immunity. At the same time, some vaccinations also can exert protective effects against some forms of pollution.

Chondroprotective and antiarthritic effects of galangin in osteoarthritis: An in vitro and in vivo study

Osteoarthritis (OA) is a common degenerative joint disease blamed for pain and disability in the elderly. Galangin (GAL) is a natural flavonoid that exhibits anti-inflammatory properties in various inflammation diseases. However, the role of GAL in OA remains unclear. In this study, we investigate the role of GAL in the progress and development of OA in vitro and vivo. The results showed that IL-1β exposure resulted in increased expression of iNOS, COX-2, MMP1, MMP3, MMP13 and ADAMTS5 in rat chondrocytes. However, co-treatment with GAL significantly decreased theses inflammatory cytokines and catabolic factors expression. In addition, GAL reduced IL-1β-induced degradation of collagen II and aggrecan in chondrocytes. Furthermore, GAL significantly suppressed IL-1β-induced Akt phosphorylation and NF-κB activation in rat chondrocytes. In vivo, intra-articular injection of GAL could also reduce the cartilage degradation in the ACLT rat model. This study reveals galangin may act as a promising novel agent in the treatment of OA.

Effect of DNA methylation on gene transcription is associated with the distribution of methylation sites across the genome in osteoarthritis

Genetics and epigenetics are important subjects in the field of osteoarthritis (OA) research. DNA methylation may affect gene transcription, but the specific mechanisms have remained to be fully elucidated. In the present study, the ChAMP methylation analysis package was used to identify differentially methylated genes (DMGs) from the dataset GSE63695 from the Gene Expression Omnibus (GEO) database. The distribution of differentially methylated sites (DMS) and the total array sites across the genome were analyzed by enrichment analysis. Subsequently, two mRNA expression profiling datasets, GSE114007 and GSE113825, were obtained from the GEO database and common differentially expressed genes (DEGs) were identified using the Limma package. Key genes were screened by analyzing the distribution of DMS across the genome consisting of DEGs and DMGs. A total of 1,662 and 1,986 DEGs were identified between OA and normal human cartilage from the GSE113825 and GSE114007 dataset, respectively. A further screening revealed 292 genes with common differences between the two datasets. A total of 574 DMS containing 394 DMGs were observed between OA and normal cartilage. Integrative analysis revealed a corresponding subset of 15 genes. Of these, 6 genes were verified by reverse transcription-quantitative PCR, confirming that the mRNA expression of 5 genes (MAP1B, FNDC1, ANLN, SCNN1A and STC2) in OA cartilage was consistent with the mRNA expression from the analysis of the datasets. Upon treatment with the DNA methylation inhibitor 5-aza-2'-deoxycytidine, the mRNA levels of FNDC1 and SCNN1A were decreased, and no significant alteration in the mRNA levels of MAP1B, ANLN, KCNN4 and STC2 was observed. The incidence of differential methylation varied in subregions of the genome and the effects on transcription were associated with the distribution of DEGs across the genome. The regulation of this appears more complex than initially postulated. Combining the data on epigenetic differences of OA with the genome or transcriptome data for analysis may improve the understanding of the pathophysiological processes of OA. FNDC1 and SCNN1A may potentially be valuable biomarkers for OA.

Cathelicidin antimicrobial peptide (CAMP) gene promoter methylation induces chondrocyte apoptosis

Objective

The occurrence of osteoarthritis is related to genetic and environmental factors. Among them, the change of chondrocyte gene expression pattern regulated by epigenetic modification is an important participant. This study analyzed the effect of CAMP gene methylation on the level of oxidative stress and inflammation of chondrocytes.

Methods

We analyzed the changes of the transcriptome in the articular cartilage tissue of osteoarthritis (OA) patients from the GSE117999 dataset. The GSE48422 dataset was used to analyze the changes in the methylation level of osteoarthritis cells. Cell Counting Kit-8 (CCK-8) and flow cytometry analysis of short hairpin RNA (shRNA) silencing CAMP gene and 5-μM 5-Aza-2’-Deoxycytidine (AZA) treatment on the proliferation and apoptosis of Human chondrocytes osteoarthritis (HC-OA) cells. The Dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay was used to detect the level of reactive oxygen species (ROS), and the expression level of inflammatory factors was analyzed by Western Blot.

Results

The expression of CAMP in cartilage tissue of OA patients was upregulated, and the level of methylation was downregulated. CAMP was highly expressed in osteoarthritis articular cartilage cells. Silencing CAMP inhibited the proliferation of HC-OA cells and promoted their apoptosis. CAMP gene methylation inhibited ROS levels and tumor necrosis factor-α (TNF-α) expression levels in HC-OA cells, and promoted transforming growth factor beta (TGF-β) expression. CAMP gene methylation inhibited the proliferation of HC-OA cells and promoted their apoptosis.

Conclusion

CAMP gene promoter methylation inhibits ROS levels and inflammation and induces chondrocyte apoptosis.

Identification of key regulators responsible for dysregulated networks in osteoarthritis by large-scale expression analysis

BACKGROUND

Osteoarthritis (OA) is a worldwide musculoskeletal disorder. However, disease-modifying therapies for OA are not available. Here, we aimed to characterize the molecular signatures of OA and to identify novel therapeutic targets and strategies to improve the treatment of OA.

METHODS

We collected genome-wide transcriptome data performed on 132 OA and 74 normal human cartilage or synovium tissues from 7 independent datasets. Differential gene expression analysis and functional enrichment were performed to identify genes and pathways that were dysregulated in OA. The computational drug repurposing method was used to uncover drugs that could be repurposed to treat OA.

RESULTS

We identified several pathways associated with the development of OA, such as extracellular matrix organization, inflammation, bone development, and ossification. By protein-protein interaction (PPI) network analysis, we prioritized several hub genes, such as JUN, CDKN1A, VEGFA, and FOXO3. Moreover, we repurposed several FDA-approved drugs, such as cardiac glycosides, that could be used in the treatment of OA.

CONCLUSIONS

We proposed that the hub genes we identified would play a role in cartilage homeostasis and could be important diagnostic and therapeutic targets. Drugs such as cardiac glycosides provided new possibilities for the treatment of OA.

Phgdh serves a protective role in Il‑1β induced chondrocyte inflammation and oxidative‑stress damage

The primary pathological changes observed in osteoarthritis (OA) involve inflammation and degeneration of chondrocytes. 3‑phosphoglycerate dehydrogenase (Phgdh), a rate‑limiting enzyme involved in the conversion of 3‑phosphoglycerate to serine, serves as a crucial molecular component of cell growth and metabolism. However, its effects on chondrocytes in OA have not been determined. In the present study, a rat model of OA was used to investigate the expression levels of Phgdh in vivo and in vitro. Additionally, the role of Phgdh in extracellular matrix (ECM) synthesis, inflammation, apoptosis and oxidative stress levels of chondrocytes was detected in vitro. Phgdh expression was decreased in OA, and Phgdh overexpression promoted ECM synthesis, decreased levels inflammatory cytokines, such as Il‑6, TNF‑α, a disintegrin and metalloproteinase with thrombospondin motifs 5 and MMP13, and decreased apoptosis. Furthermore, expression of Phgdh effectively increased expression levels of the cellular antioxidant enzymes catalase and superoxide dismutase 1, and decreased the levels of reactive oxygen species in chondrocytes; and this may have been regulated by a Kelch like ECH associated protein 1/nuclear factor erythroid 2‑related factor 2 axis. Taken together, these results suggest that Phgdh may be used to manage the progression of OA.

HDAC2 interacts with microRNA-503-5p to regulate SGK1 in osteoarthritis

Background

Osteoarthritis (OA) is a disabling joint disease that causes articular cartilage degeneration. It has been implicated that altered expression of histone deacetylase 2 (HDAC2) is found in patients with OA. However, the specific role of HDAC2 in the development of OA still remains enigmatic. Hence, we sought to characterize the functional relevance of HDAC2 in the development of OA.

Methods

Anterior cruciate ligament surgery was performed to generate the rat model of OA. Luciferase assay was performed to evaluate the relationship between microRNA-503-5p (miR-503-5p) and serum- and glucocorticoid-inducible kinase-1 (SGK1). Functional experiments were conducted to examine the functional significance of miR-503-5p, histone deacetylase 2 (HDAC2), and SGK1 on the progression of OA by determining proliferation, apoptosis, and expression of apoptosis-associated proteins and inflammatory cytokines.

Results

HDAC2 could inhibit miR-503-5p expression. SGK1 was the target gene of miR-503-5p. Upregulation of miR-503-5p or silencing of HDAC2 contributed to enhanced proliferation, suppressed apoptosis (reduced expression of Caspase-3 and Bax but elevated expression of Bcl2), and promoted inflammation in chondrocytes of OA rats.

Conclusion

In conclusion, our study demonstrated that HDAC2 could promote OA through miR-503-5p/SGK1 axis, which might function as a therapeutic target for OA treatment.

Beneficial Effect of Tempol, a Membrane-Permeable Radical Scavenger, on Inflammation and Osteoarthritis in In Vitro Models

Osteoarthritis (OA) is one of the most common and widespread diseases which is highly disabling for humans. This makes OA a chronic disease for which it is urgent to find new therapeutic strategies. The inflammatory state in OA contributes to its progression through multiple mechanisms involving the recruitment of phagocytes and leukocytes, inflammatory response, and reactive oxygen species (ROS) production. Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) is classifiable as a piperidine nitroxide, with excellent antioxidant effects, while its anti-inflammatory role is not yet clear. On this basis, we explored its promising biological properties in two in vitro model:, macrophage (J774) and chondrocyte (CC) cell lines. With this aim in mind, we induced inflammation in J774 and CC using lipopolysaccharide (LPS) and Interleukin1β (IL-1β), and after 24, 72 and 168 h of tempol treatment analyzed their effects on cytotoxicity and anti-inflammatory activity. Our data suggested that tempol treatment is able to reduce inflammation and nitrite production in LPS-induced J774 as well as reducing the production of proinflammatory mediators including cytokines, enzymes, and metalloproteases (MMPs) in IL-1β-stimulated CC. Thus, since inflammation and oxidative stress have a crucial role in the pathogenesis and progression of OA, tempol could be considered as a new therapeutic approach for this pathology.

Combination of baicalein and miR-106a-5p mimics significantly alleviates IL-1β-induced inflammatory injury in CHON-001 cells

Osteoarthritis (OA) induces inflammation and degeneration of all joint components, and as such, is a considerable source of disability, pain and socioeconomic burden worldwide. Baicalein (BAI) and microRNA (miR)-106a-5p suppress the progression of OA; however, the effects of BAI and miR-106a-5p for the combined treatment of OA are not completely understood. An in vitro OA model was established by treating CHON-001 cells with 20 ng/ml interleukin (IL)-1β. Cell Counting Kit-8 and flow cytometry assays were conducted to evaluate cell viability and apoptosis, respectively. Western blotting was performed to determine the expression levels of Bax, active caspase-3, Bcl-2, collagen I, collagen III, aggrecan, matrix metallopeptidase (MMP)-13, MMP-9, active Notch1 and transcription factor hes family bHLH transcription factor 1 (Hes1). The levels of IL-6 and tumor necrosis factor-α in the cell culture medium were quantified via ELISA. The present study revealed that treatment with BAI or miR-106a-5p mimic alleviated IL-1β-induced apoptosis, and BAI + miR-106a-5p combination treatment exerted enhanced anti-inflammatory effects compared with monotherapy. Furthermore, IL-1β-induced accumulation of collagen, collagen III, MMP-13 and MMP-9 in CHON-001 cells was reversed to a greater degree following combination treatment compared with monotherapy. Likewise, IL-1β-induced aggrecan degradation was markedly reversed by combination treatment. IL-1β-induced upregulation of active Notch1 and Hes1 in CHON-001 cells was also significantly attenuated by combined BAI + miR-106a-5p treatment. In conclusion, the results of the present study revealed that the combination of BAI and miR-106a-5p mimic significantly decreased IL-1β-induced inflammatory injury in CHON-001 cells, which may serve as a novel therapeutic strategy for OA.

Experimental Therapeutics for the Treatment of Osteoarthritis

Osteoarthritis (OA) therapy remains a large challenge since no causative treatment options are so far available. Despite some main pathways contributing to OA are identified its pathogenesis is still rudimentary understood. A plethora of therapeutically promising agents are currently tested in experimental OA research to find an opportunity to reverse OA-associated joint damage and prevent its progression. Hence, this review aims to summarize novelly emerging experimental approaches for OA. Due to the diversity of strategies shown only main aspects could be summarized here including herbal medicines, nanoparticular compounds, growth factors, hormones, antibody-, cell- and extracellular vesicle (EV)-based approaches, optimized tools for joint viscosupplementation, genetic regulators such as si- or miRNAs and promising combinations. An abundant multitude of compounds obtained from plants, environmental, autologous or synthetic sources have been identified with anabolic, anti-inflammatory, -catabolic and anti-apoptotic properties. Some ubiquitous signaling pathways such as wingless and Integration site-1 (Wnt), Sirtuin, Toll-like receptor (TLR), mammalian target of rapamycin (mTOR), Nuclear Factor (NF)-κB and complement are involved in OA and addressed by them. Hyaluronan (HA) provided benefit in OA since many decades, and novel HA formulations have been developed now with higher HA content and long-term stability achieved by cross-linking suitable to be combined with other agents such as components from herbals or chemokines to attract regenerative cells. pH- or inflammation-sensitive nanoparticular compounds could serve as versatile slow-release systems of active compounds, for example, miRNAs. Some light has been brought into the intimate regulatory network of small RNAs in the pathogenesis of OA which might be a novel avenue for OA therapy in future. Attraction of autologous regenerative cells by chemokines and exosome-based treatment strategies could also innovate OA therapy.

Inhibiting TLR4 signaling by linarin for preventing inflammatory response in osteoarthritis

Osteoarthritis (OA) is one of the most common degenerative diseases, ultimately leading to long-term joint pain and severe articular malformation. Controlling local chronic inflammation is a crucial strategy for delaying OA development. Linarin is a natural flavonoid glycoside that is widely available in Compositae, Chrysanthemum indicum and Dendrocalamus and processes protective effects in several animal models. The purpose of our work was to study the protective effect of Linarin for OA. Cellular experiments data showed that Linarin suppressed lipopolysaccharide (LPS)-caused the overproduction of nitric oxide (NO), prostaglandin E2 (PGE2), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) in chondrocyte. In addition, LPS-stimulated expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide nitrate (iNOS) was decreased by Linarin pre-treatment. Together, Linarin prevented the catabiosis of extracellular matrix caused by LPS. For mechanism, Linarin inhibited the formation of Toll-like receptor 4 (TLR4) / myeloid differentiation protein-2 (MD-2) dipolymer complex and subsequently intervened NF-κB activation. Our mouse DMM model further clarified the protection of Linarin in vivo. In summary, our results suggested that Linarin may be a potential effective agent for OA.

Integrative multiomics analysis of Premolis semirufa caterpillar venom in the search for molecules leading to a joint disease

The joint disease called pararamosis is an occupational disease caused by accidental contact with bristles of the caterpillar Premolis semirufa. The chronic inflammatory process narrows the joint space and causes alterations in bone structure and cartilage degeneration, leading to joint stiffness. Aiming to determine the bristle components that could be responsible for this peculiar envenomation, in this work we have examined the toxin composition of the caterpillar bristles extract and compared it with the differentially expressed genes (DEGs) in synovial biopsies of patients affected with rheumatoid arthritis (RA) and osteoarthritis (OA). Among the proteins identified, 129 presented an average of 63% homology with human proteins and shared important conserved domains. Among the human homologous proteins, we identified seven DEGs upregulated in synovial biopsies from RA or OA patients using meta-analysis. This approach allowed us to suggest possible toxins from the pararama bristles that could be responsible for starting the joint disease observed in pararamosis. Moreover, the study of pararamosis, in turn, may lead to the discovery of specific pharmacological targets related to the early stages of articular diseases.

Therapeutic effects of turmeric or curcumin extract on pain and function for individuals with knee osteoarthritis: a systematic review

Purpose

To determine whether supplementation with turmeric or curcumin extract effects pain and physical function in individuals with knee osteoarthritis (OA). Second, we investigated the therapeutic response (pain and function) of turmeric compared with non-steroidal anti-inflammatory drugs (NSAIDs).

Methods

A search was conducted in MEDLINE, Embase, CINAHL and Cochrane Review. Inclusion criteria included randomised controlled trials reporting pain and physical function in humans with knee OA comparing turmeric therapy with NSAIDs or no therapy. Two reviewers screened 5273 abstracts. Risk of bias and quality were assessed via Cochrane Collaboration tool and CONSORT (Consolidated Standards of Reporting Trials) 2010, respectively.

Results

Ten studies were included in the final analysis. Eight had high methodological quality and two were categorised as good with a mean CONSORT quality score of 21.1. Nine studies had adequate sequence generation and six had adequate allocation concealment. Participants and outcome assessors were blinded in eight studies. Three of the studies compared turmeric therapy to NSAIDs. All 10 studies showed improvement in pain and function from baseline with turmeric therapy (p≤0.05). In three studies comparing turmeric to NSAIDs, there were no differences in outcome scores (p>0.05). In all studies there were no significant adverse events in the turmeric therapy group.

Conclusion

Compared with placebo, there appears to be a benefit of turmeric on knee OA pain and function. Based on a small number of studies the effects are similar to that of NSAIDs. Variables such as optimal dosing, frequency and formulation remain unclear at this time.

LncRNA SNHG7 alleviates IL-1β-induced osteoarthritis by inhibiting miR-214-5p-mediated PPARGC1B signaling pathways

BACKGROUND

As a common joint disease, osteoarthritis (OA) is the main cause of limited joint mobility and disability. The role of lncRNAs in the regulation of OA is increasingly discovered. Therefore, further exploring the function of SNHG7 in OA is of great significance for understanding its occurrence and development.

METHODS

We used interleukin-1β (IL-1β) to treat to establish an OA model primary on chondrocytes in vitro, and gain- and loss of function assays of SNHG7 and miR-214-5p were conducted. The cell viability and apoptosis of chondrocytes were detected by CCK8 assay, BrdU assay and flow cytometry. The inflammatory cytokines (IL-1β, IL-6 and TNF-α), NLRP3 inflammasome, protein level of PPARGC1B, PPARγ, P38 and NF-κB were determined by RT-PCR and/or western blot.

RESULTS

The results showed that SNHG7 was distinctly downregulated, while miR-214-5p was significantly upregulated in OA patients and primary chondrocytes treated with IL-1β. In addition, SNHG7 enhanced cell viability, inhibited apoptosis and inflammation of IL-1β-mediated chondrocytes. In contrast, miR-214-5p upregulation reduced viability, promoted apoptosis and inflammation of chondrocytes. Mechanistically, SNHG7 served as a competitive endogenous RNA by sponging miR-214-5p, which targeted PPARGC1B. Besides, the results of the compensation experiment affirmed that miR-214-5p attenuates SNHG7-mediated protective effects on IL-1β-mediated chondrocytes against apoptosis and inflammation, and activating PPARγ pathway markedly dampened the cytotoxic effects of miR-214-5p.

CONCLUSIONS

Collectively, The above results confirmed that SNHG7 prevents IL-1β induced OA by inhibiting NLRP3 inflammasome and apoptosis through miR-214-5p/PPARGC1B axis.

Novel Insights Into the Role of N6-Methyladenosine RNA Modification in Bone Pathophysiology

Thus far, there are more than known 150 modifications to RNA, in which common internal modifications of mRNA include N6-methyladenosine (m6A), N1-methyladenosine, and 5-methylcytosine. Among them, m6A RNA modification is one of the highest abundance modifications in eukaryotes, regulating mechanisms controlling gene expression at the post-transcription level. As an invertible and dynamic epigenetic marker, m6A base modification influences almost all vital biological processes, cellular components, and molecular functions. Once the m6A modification process is abnormal, a series of diseases-including cancer, neurological diseases, and growth disorders-will be caused. Besides, several base modification activities also have been created by noncoding RNAs (ncRNAs), for instance, microRNAs, and circular RNAs, long ncRNAs, which were dynamically regulated during bone and cartilage pathophysiology processes. Therefore, it has now been clear that dynamic modification on coding RNAs and ncRNAs represents a completely new way to modulate genetic information. In this review, we highlight up-to-date progress and applications of m6A RNA modification in bone and cartilage pathophysiology, and we discuss the pathological roles and underlying molecular mechanism of m6A modifications in osteoarthritis and osteoporosis and osteosarcoma pathogenesis.

Sustained Acoustic Medicine Combined with A Diclofenac Ultrasound Coupling Patch for the Rapid Symptomatic Relief of Knee Osteoarthritis: Multi-Site Clinical Efficacy Study

BACKGROUND

Sustained Acoustic Medicine (SAM) is an emerging, non-invasive, non-narcotic, home-use ultrasound therapy for the daily treatment of joint pain. The aim of this multi-site clinical study was to examine the efficacy of long-duration continuous ultrasound combined with a 1% diclofenac ultrasound gel patch in treating pain and improving function in patients with knee osteoarthritis.

METHODS

The Consolidated Standards of Reporting Trials (CONSORT) were followed. Thirty-two (32) patients (18-males, 14-females) 54 years of average age with moderate to severe knee pain and radiographically confirmed knee osteoarthritis (Kellgren-Lawrence (KL) grade II/III) were enrolled for treatment with the SAM device and diclofenac patch applied daily to the treated knee. SAM ultrasound (3 MHz, 0.132 W/cm2, 1.3 W) and 6 grams of 1% diclofenac were applied with a wearable device for 4 hours daily for 1 week, delivering 18,720 Joules of ultrasound energy per treatment. The primary outcome was the daily change in pain intensity using a numeric rating scale (NRS 0-10), which was assessed prior to intervention (baseline, day 1), before and after each daily treatment, and after 1 week of daily treatment (day 7). Rapid responders were classified as those patients exhibiting greater than a 1-point reduction in pain following the first treatment. Change in Western Ontario McMaster Osteoarthritis Questionnaire (WOMAC) score from baseline to day 7 was the secondary functional outcome measure. Additionally, a series of daily usability and user experience questions related to devising ease of use, functionality, safety, and effectiveness, were collected. Data were analyzed using t-tests and repeated measure ANOVAs.

RESULTS

The study had a 94% retention rate, and there were no adverse events or study-related complaints across 224 unique treatment sessions. Rapid responders included 75% of the study population. Patients exhibited a significant mean NRS pain reduction over the 7-day study of 2.06-points (50%) for all subjects (n=32, p<0.001) and 2.96-points (70%) for rapid responders (n=24, p<0.001). The WOMAC functional score significantly improved by 351 points for all subjects (n=32, p<0.001), and 510 points for rapid responders (n=24, p<0.001). Over 95% of patients found the device safe, effective and easy to use, and would continue treatment for their knee OA symptoms.

CONCLUSION

Sustained Acoustic Medicine combined with 1% topical diclofenac rapidly reduced pain and improved function in patients with moderate to severe osteoarthritis-related knee pain. The clinical findings suggest that this treatment approach may be used as a conservative, non-invasive treatment option for patients with knee osteoarthritis. Additional research is warranted on non-weight bearing joints of the musculoskeletal system as well as different topical drugs that could benefit from improved localized delivery.Clinical Trial Registry Number: (NCT04391842).

Pathological mechanism of joint destruction in haemophilic arthropathy

Haemophilic arthropathy (HA), caused by intra-articular haemorrhage, is one of the most common complications in patients with haemophilia. Factor replacement therapy provides missing coagulation factors to prevent children with haemophilia from joint bleeding and decreases their risk for HA. However, haemophilia patients in developing countries are still suffering from HA due to insufficient replacement therapy. Symptoms such as pain and activity limitations caused by HA seriously affect the functional abilities and quality of life of patients with HA, causing a high disability rate in the haemophilia cohort. The pathological mechanism of HA is complicated because the whole pathological mainly involves hypertrophic synovitis, osteopenia, cartilage and bone destruction, and these pathological changes occur in parallel and interact with each other. Inflammation plays an important role in the whole complex pathological process, and iron, cytokines, growth factors and other factors are involved. This review summarizes the pathological mechanism of HA to provide background for clinical and basic research.

Mitochondrial dysfunction triggers a catabolic response in chondrocytes via ROS-mediated activation of the JNK/AP1 pathway

Mitochondrial function is impaired in osteoarthritis (OA) but its impact on cartilage catabolism is not fully understood. Here, we investigated the molecular mechanism of mitochondrial dysfunction-induced activation of the catabolic response in chondrocytes. Using cartilage slices from normal and OA cartilage, we showed that mitochondrial membrane potential was lower in OA cartilage, and that this was associated with increased production of mitochondrial superoxide and catabolic genes [interleukin 6 (IL-6), COX-2 (also known as PTGS2), MMP-3, -9, -13 and ADAMTS5]. Pharmacological induction of mitochondrial dysfunction in chondrocytes and cartilage explants using carbonyl cyanide 3-chlorophenylhydrazone increased mitochondrial superoxide production and the expression of IL-6, COX-2, MMP-3, -9, -13 and ADAMTS5, and cartilage matrix degradation. Mitochondrial dysfunction-induced expression of catabolic genes was dependent on the JNK (herein referring to the JNK family)/activator protein 1 (AP1) pathway but not the NFκB pathway. Scavenging of mitochondrial superoxide with MitoTEMPO, or pharmacological inhibition of JNK or cFos and cJun, blocked the mitochondrial dysfunction-induced expression of the catabolic genes in chondrocytes. We demonstrate here that mitochondrial dysfunction contributes to OA pathogenesis via JNK/AP1-mediated expression of catabolic genes. Our data shows that AP1 could be used as a therapeutic target for OA management.This article has an associated First Person interview with the first author of the paper.

GSK5182, 4-Hydroxytamoxifen Analog, a New Potential Therapeutic Drug for Osteoarthritis

Estrogen-related receptors (ERRs) are the first identified orphan nuclear receptors. The ERR family consists of ERRα, ERRβ, and ERRγ, regulating diverse isoform-specific functions. We have reported the importance of ERRγ in osteoarthritis (OA) pathogenesis. However, therapeutic approaches with ERRγ against OA associated with inflammatory mechanisms remain limited. Herein, we examined the therapeutic potential of a small-molecule ERRγ inverse agonist, GSK5182 (4-hydroxytamoxifen analog), in OA, to assess the relationship between ERRγ expression and pro-inflammatory cytokines in mouse articular chondrocyte cultures. ERRγ expression increased following chondrocyte exposure to various pro-inflammatory cytokines, including interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. Pro-inflammatory cytokines dose-dependently increased ERRγ protein levels. In mouse articular chondrocytes, adenovirus-mediated ERRγ overexpression upregulated matrix metalloproteinase (MMP)-3 and MMP-13, which participate in cartilage destruction during OA. Adenovirus-mediated ERRγ overexpression in mouse knee joints or ERRγ transgenic mice resulted in OA. In mouse joint tissues, genetic ablation of Esrrg obscured experimental OA. These results indicate that ERRγ is involved in OA pathogenesis. In mouse articular chondrocytes, GSK5182 inhibited pro-inflammatory cytokine-induced catabolic factors. Consistent with the in vitro results, GSK5182 significantly reduced cartilage degeneration in ERRγ-overexpressing mice administered intra-articular Ad-Esrrg. Overall, the ERRγ inverse agonist GSK5182 represents a promising therapeutic small molecule for OA.

FoxO1 is a crucial mediator of TGF-β/TAK1 signaling and protects against osteoarthritis by maintaining articular cartilage homeostasis

Transforming growth factor-β (TGF-β) signaling is a critical regulator for articular cartilage tissue maintenance and chondrocyte homeostasis. Nonetheless, the regulatory networks and downstream signaling pathways that govern the chondroprotective function of TGF-β in the context of osteoarthritis (OA) are not fully defined. Recent studies reveal that mice with postnatal deletion of triple forkhead box class Os (FoxOs) (1, 3, and 4) spontaneously develop OA-like pathologies. The OA phenotype largely recapitulates that observed in mice with loss of TGF-βR2. In the present study, we investigated the role of FoxOs as downstream mediators of TGF-β signaling and define their role in articular cartilage homeostasis. Among the three FoxOs (1, 3, and 4), TGF-β signaling exclusively regulates FoxO1 in a TGF-β activated kinase 1 (TAK1)-dependent manner. Furthermore, FoxO1 was genetically ablated in mice in a tissue-specific manner in articular cartilage or overexpressed in adult cartilage immediately followed by meniscal/ligament injury (MLI). Histological and microcomputed tomography (micro-CT) analyses demonstrated that loss of FoxO1 postnatally in articular cartilage leads to OA-like pathologies, and gain of FoxO1 in adult cartilage has both preventative and therapeutic effects on surgically induced OA. Mechanistically, FoxO1 was found to maintain articular chondrocyte homeostasis through induction of anabolic and autophagy-related gene expressions. Importantly, overexpression of FoxO1 markedly rescued the OA phenotypes caused by deficiency in TGF-β signaling in chondrocytes. Our study identifies that TGF-β/TAK1-FoxO1 is a key signaling cascade in regulation of articular cartilage autophagy and homeostasis and is a potentially important therapeutic target for OA-like joint diseases.

Anti-inflammatory activity of Radix Angelicae biseratae in the treatment of osteoarthritis determined by systematic pharmacology and in vitro experiments

Radix Angelicae biseratae is a widely used Chinese traditional herbal medicine for osteoarthritis (OA). Its therapeutic efficacy has been confirmed in clinical practice. However, its mechanisms of action in treating OA have remained elusive. The purpose of the present study was to identify active components with good oral bioavailability and drug-like properties from Radix Angelicae biseratae through systematic pharmacology and in vitro experiments to determine targets of Radix Angelicae biseratae in the treatment of OA. The functional components of Radix Angelicae biseratae were screened from the Traditional Chinese Medicine Systems Pharmacology database based on oral bioavailability and drug-like properties. Subsequently, the databases STITCH, Open Targets Platform and DrugBank were searched and microarray analysis was performed to screen the active components of Radix Angelicae biseratae to treat OA and predict its potential target proteins. The interaction network and protein interaction network were then generated and examined, molecular docking between active components and targets was performed and the enrichment of potential target proteins was analyzed. Finally, reverse transcription-quantitative (RT-q)PCR and western blot analyses were used to verify the therapeutic effect of Radix Angelicae biseratae extract on the expression of OA-associated target proteins. The results provided eight active components in Radix Angelicae biseratae, which were firmly linked to 20 targets of OA. In combination with molecular docking and the analysis of the interaction network between components and targets, it was suggested that sitosterol was a major active component of Radix Angelicae biseratae in the treatment of OA. Protein interaction network analysis suggested that prostaglandin-endoperoxide synthase 2 (PTGS2), nitric oxide synthase 3 and cytochrome P450 2B6 may be critical targets for Radix Angelicae biseratae in the treatment of OA. In addition, RT-qPCR and western blot analyses suggested that Radix Angelicae biseratae extract inhibited the mRNA and protein expression of PTGS2 in degenerative articular cartilage cells in vitro, whilst other targets remain to be verified. Functional enrichment analysis indicated that Radix Angelicae biseratae confers pharmacological efficacy towards OA through exerting anti-inflammatory effects and immune regulation.

Inhibition of EZH2 (Enhancer of Zeste Homolog 2) Attenuates Neuroinflammation via H3k27me3/SOCS3/TRAF6/NF-κB (Trimethylation of Histone 3 Lysine 27/Suppressor of Cytokine Signaling 3/Tumor Necrosis Factor Receptor Family 6/Nuclear Factor-κB) in a Rat Model of Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Neuroinflammation has been proven to play an important role in the pathogenesis of early brain injury after subarachnoid hemorrhage (SAH). EZH2 (enhancer of zeste homolog 2)-mediated H3K27Me3 (trimethylation of histone 3 lysine 27) has been recognized to play a critical role in multiple inflammatory diseases. However, there is still a lack of evidence to address the effect of EZH2 on the immune response of SAH. Therefore, the aim of this study was to determine the role of EZH2 in SAH-induced neuroinflammation and explore the effect of EZH2 inhibition with its specific inhibitor EPZ6438.

METHODS

The endovascular perforation method was performed on rats to induce subarachnoid hemorrhage. EPZ6438, a specific EZH2 inhibitor, was administered intraperitoneally at 1 hour after SAH. SOCS3 (Suppressor of cytokine signaling 3) siRNA and H3K27me3 CRISPR were administered intracerebroventricularly at 48 hours before SAH to explore potential mechanisms. The SAH grade, short-term and long-term neurobehavioral tests, immunofluorescence staining, and western blots were performed after SAH.

RESULTS

The expression of EZH2 and H3K27me3 peaked at 24 hours after SAH. In addition, inhibition of EZH2 with EPZ6438 significantly improved neurological deficits both in short-term and long-term outcome studies. Moreover, EPZ6438 treatment significantly decreased the levels of EZH2, H3K27Me3, pathway-related proteins TRAF6 (TNF [tumor necrosis factor] receptor family 6), NF-κB (nuclear factor-κB) p65, proinflammatory cytokines TNF-α, IL (interleukin)-6, IL-1β, but increased the expression levels of SOCS3 and anti-inflammatory cytokine IL-10. Furthermore, administration of SOCS3 siRNA and H3k27me3-activating CRISPR partly abolished the neuroprotective effect of EPZ6438, which indicated that the neuroprotective effect of EPZ6438 acted, at least partly, through activation of SOCS3.

CONCLUSIONS

In summary, the inhibition of EZH2 by EPZ6438 attenuated neuroinflammation via H3K27me3/SOCS3/TRAF6/NF-κB signaling pathway after SAH in rats. By targeting EZH2, this study may provide an innovative method to ameliorate early brain injury after SAH.

Effects of Interleukin-1β Inhibition on Incident Hip and Knee Replacement : Exploratory Analyses From a Randomized, Double-Blind, Placebo-Controlled Trial

BACKGROUND

Osteoarthritis is a common inflammatory disorder with no disease-modifying therapies. Whether inhibition of interleukin-1β (IL-1β) can reduce the consequences of large joint osteoarthritis is unclear.

OBJECTIVE

To determine whether IL-1β inhibition with canakinumab reduces incident total hip or knee replacement (THR/TKR).

DESIGN

Exploratory analysis of a randomized trial. (ClinicalTrials.gov: NCT01327846).

SETTING

1091 clinical sites in 39 countries.

PARTICIPANTS

10 061 CANTOS (Canakinumab Anti-inflammatory Thrombosis Outcomes Study) participants.

INTERVENTION

Random allocation to placebo or canakinumab (50, 150, or 300 mg) subcutaneously once every 3 months.

MEASUREMENTS

The primary and secondary outcomes were time to first incident THR/TKR and time to first occurrence of an osteoarthritis-related adverse event (AE). Data were obtained through blinded ascertainment of trial clinical and safety databases.

RESULTS

Median follow-up was 3.7 years. For the individual canakinumab dose groups, compared with placebo, hazard ratios (HRs) for incident THR/TKR during follow-up were 0.60 (95% CI, 0.38 to 0.95) for the 50-mg group, 0.53 (CI, 0.33 to 0.84) for the 150-mg group, and 0.60 (CI, 0.38 to 0.93) for the 300-mg group. Thus, in the pooled canakinumab groups, compared with the placebo group, incidence rates for THR/TKR were 0.31 and 0.54 events per 100 person-years (HR, 0.58 [CI, 0.42 to 0.80]; P = 0.001), respectively. The HR for the secondary end point of osteoarthritis-related AEs was 0.73 (CI, 0.61 to 0.87). Similar findings were observed in analyses restricted to participants with a history of osteoarthritis.

LIMITATION

Because the parent trial was not designed to examine the efficacy of IL-1β inhibitors in osteoarthritis, information on structural joint outcomes was not collected.

CONCLUSION

Findings from this exploratory analysis of a randomized controlled trial support further investigation of IL-1β inhibition for treatment of large joint osteoarthritis.

PRIMARY FUNDING SOURCE

Novartis Pharmaceuticals.

Multifaceted Functions and Novel Insight Into the Regulatory Role of RNA N6-Methyladenosine Modification in Musculoskeletal Disorders

RNA modifications have emerged as key regulators of transcript expression in diverse physiological and pathological processes. As one of the most prevalent types of RNA modifications, N⁶-methyladenosine (m⁶A) has become the highlight in modulation of various diseases through interfering RNA splicing, translation, nuclear export, and decay. In many cases, the detailed functions of m⁶A in cellular processes and diseases remain unclear. Notably, recent studies have determined the relationship between m⁶A modification and musculoskeletal disorders containing osteosarcoma, osteoarthritis, rheumatoid arthritis, osteoporosis, etc. Herein, this review comprehensively summarizes the recent advances of m⁶A modification in pathogenesis and progression of musculoskeletal diseases. Specifically, the underlying molecular mechanisms, detection technologies, regulatory functions, clinical implications, and future perspectives of m⁶A in musculoskeletal disorders are discussed, with the aim to provide a novel insight into their association.

Oxidative stress and inflammation in osteoarthritis pathogenesis: Role of polyphenols

Osteoarthritis (OA) is the most prevalent joint degenerative disease leading to irreversible structural and functional changes in the joint and is a major cause of disability and reduced life expectancy in ageing population. Despite the high prevalence of OA, there is no disease modifying drug available for the management of OA. Oxidative stress, a result of an imbalance between the production of reactive oxygen species (ROS) and their clearance by antioxidant defense system, is high in OA cartilage and is a major cause of chronic inflammation. Inflammatory mediators, such as interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) are highly upregulated in OA joints and induce ROS production and expression of matrix degrading proteases leading to cartilage extracellular matrix degradation and joint dysfunction. ROS and inflammation are interdependent, each being the target of other and represent ideal target/s for the treatment of OA. Plant polyphenols possess potent antioxidant and anti-inflammatory properties and can inhibit ROS production and inflammation in chondrocytes, cartilage explants and in animal models of OA. The aim of this review is to discuss the chondroprotective effects of polyphenols and modulation of different molecular pathways associated with OA pathogenesis and limitations and future prospects of polyphenols in OA treatment.

Emerging Gene-Editing Modalities for Osteoarthritis

Osteoarthritis (OA) is a pathological degenerative condition of the joints that is widely prevalent worldwide, resulting in significant pain, disability, and impaired quality of life. The diverse etiology and pathogenesis of OA can explain the paucity of viable preventive and disease-modifying strategies to counter it. Advances in genome-editing techniques may improve disease-modifying solutions by addressing inherited predisposing risk factors and the activity of inflammatory modulators. Recent progress on technologies such as CRISPR/Cas9 and cell-based genome-editing therapies targeting the genetic and epigenetic alternations in OA offer promising avenues for early diagnosis and the development of personalized therapies. The purpose of this literature review was to concisely summarize the genome-editing options against chronic degenerative joint conditions such as OA with a focus on the more recently emerging modalities, especially CRISPR/Cas9. Future advancements in novel genome-editing therapies may improve the efficacy of such targeted treatments.

The miRNA-mRNA interactome of murine induced pluripotent stem cell-derived chondrocytes in response to inflammatory cytokines

Osteoarthritis (OA) is a degenerative joint disease, and inflammation within an arthritic joint plays a critical role in disease progression. Pro-inflammatory cytokines, specifically IL-1 and TNF-α, induce aberrant expression of catabolic and degradative enzymes and inflammatory cytokines in OA and result in a challenging environment for cartilage repair and regeneration. MicroRNAs (miRNAS) are small noncoding RNAs and are important regulatory molecules that act by binding to target messenger RNAs (mRNAs) to reduce protein synthesis and have been implicated in many diseases, including OA. The goal of this study was to understand the mechanisms of miRNA regulation of the transcriptome of tissue-engineered cartilage in response to IL-1β and TNF-α using an in vitro murine induced pluripotent stem cell (miPSC) model system. We performed miRNA and mRNA sequencing to determine the temporal and dynamic responses of genes to specific inflammatory cytokines as well as miRNAs that are differentially expressed (DE) in response to both cytokines or exclusively to IL-1β or TNF-α. Through integration of mRNA and miRNA sequencing data, we created networks of miRNA-mRNA interactions which may be controlling the response to inflammatory cytokines. Within the networks, hub miRNAs, miR-29b-3p, miR-17-5p, and miR-20a-5p, were identified. As validation of these findings, we found that delivery of miR-17-5p and miR-20a-5p mimics significantly decreased degradative enzyme activity levels while also decreasing expression of inflammation-related genes in cytokine-treated cells. This study utilized an integrative approach to determine the miRNA interactome controlling the response to inflammatory cytokines and novel mediators of inflammation-driven degradation in tissue-engineered cartilage.

In vitro Evaluation of the Anti-inflammatory Effects of Thymoquinone in Osteoarthritis and in silico Analysis of Inter-Related Pathways in Age-Related Degenerative Diseases

Chronic inflammation is a common underlying factor in osteoarthritis (OA) and most age-related degenerative diseases. As conventional therapies help only in partial alleviation of symptoms in OA, stem cell-based therapies and herbal supplements are being widely explored. Thymoquinone (TQ), an active ingredient of Nigella sativa is reported to have immunomodulatory, anti-inflammatory and antioxidant properties. We evaluated the effects of TQ on bone marrow MSCs (BM-MSCs) derived from OA patients and its interrelated pathways in inflammation and age-related degenerative diseases using Ingenuity Pathway Analysis (IPA) as well as possible molecular targets using SwissTargetPrediction. BM-MSCs were derived from OA patients and their stemness properties were characterized by studying the MSCs related CD surface marker expression and differentiation into adipocytes, osteoblasts, and chondrocytes. Treatment with TQ (100 nM-5 μM) demonstrated cell death, especially at higher concentrations. MTT assay demonstrated a significant concentration-dependent decrease in cell viability which ranged from 20.04% to 69.76% with higher doses (300 nM, 1 μM, and 5 μM), especially at 48h and 72h. Additional cell viability testing with CellTiter-Blue also demonstrated a significant concentration-dependent decrease in cell viability which ranged from 27.80 to 73.67% with higher doses (300 nM, 1 μM, 3 μM, and 5 μM). Gene expression analysis following treatment of BM-MSCs with TQ (1 and 3 μM) for 48h showed upregulation of the anti-inflammatory genes IL-4 and IL-10. In contrast, the pro-inflammatory genes namely IFN-γ, TNF-α, COX-2, IL-6, IL-8, IL-16, and IL-12A although were upregulated, compared to the lower concentration of TQ (1 μM) they were all decreased at 3 μM. The pro-apoptotic BAX gene was downregulated while the SURVIVIN gene was upregulated. IPA of the molecular interaction of TQ in inflammation and age-related degenerative diseases identified canonical pathways directly related to synaptogenesis, neuroinflammation, TGF-β, and interleukin signaling. Further screening led to the identification of 36 molecules that are involved in apoptosis, cell cycle regulation, cytokines, chemokines, and growth factors. SwissTargetPrediction of TQ identified potential molecular targets with high probability. TQ exerted anti-inflammatory effects and therefore can be a useful adjuvant along with conventional therapies against inflammation in OA and other age-related degenerative diseases.

Epigenetic Clock: DNA Methylation in Aging

Aging, which is accompanied by decreased organ function and increased disease incidence, limits human lifespan and has attracted investigators for thousands of years. In recent decades, with the rapid development of biology, scientists have shown that epigenetic modifications, especially DNA methylation, are key regulators involved in this process. Regular fluctuations in global DNA methylation levels have been shown to accurately estimate biological age and disease prognosis. In this review, we discuss recent findings regarding the relationship between variations in DNA methylation level patterns and aging. In addition, we introduce the known mechanisms by which DNA methylation regulators affect aging and related diseases. As more studies uncover the mechanisms by which DNA methylation regulates aging, antiaging interventions and treatments for related diseases may be developed that enable human life extension.

Stimulating Factors and Origins of Precursor Cells in Traumatic Heterotopic Ossification Around the Temporomandibular Joint in Mice

The contributing factors and the origins of precursor cells in traumatic heterotopic ossification around the temporomandibular joint (THO-TMJ), which causes obvious restriction of mouth opening and maxillofacial malformation, remain unclear. In this study, our findings demonstrated that injured chondrocytes in the condylar cartilage, but not osteoblasts in the injured subchondral bone, played definite roles in the development of THO-TMJ in mice. Injured condylar chondrocytes without articular disc reserves might secrete growth factors, such as IGF1 and TGFβ2, that stimulate precursor cells, such as endothelial cells and muscle-derived cells, to differentiate into chondrocytes or osteoblasts and induce THO-TMJ. Preserved articular discs can alleviate the pressure on the injured cartilage and inhibit the development of THO-TMJ by inhibiting the secretion of these growth factors from injured chondrocytes. However, the exact molecular relationships among trauma, the injured condylar cartilage, growth factors such as TGFβ2, and pressure need to be explored in detail in the future.

ABIN-1 protects chondrocytes from lipopolysaccharide-induced inflammatory injury through the inactivation of NF-κB signalling

The A20-binding inhibitor of nuclear factor (NF)-κB-1 (ABIN-1) protein has recently been implicated as a key regulator of inflammation with involvement in multiple inflammatory diseases. However, the function of ABIN-1 in osteoarthritis (OA) remains unclear. In the current study, we explored the role of ABIN-1 in the regulation of lipopolysaccharide (LPS)-induced inflammatory injury of chondrocytes, which served as an in vitro model of OA. Results revealed that ABIN-1 expression was induced by chondrocyte exposure to LPS. ABN-1 silencing exacerbated LPS-induced apoptosis and the inflammatory response, while ABIN-1 overexpression alleviated the inflammatory response and LPS-induced apoptosis in chondrocytes. Moreover, ABIN-1 overexpression resulted in significantly decreased LPS-induced NF-κB activation. Notably, activation of NF-κB signalling significantly reversed ABIN-1-mediated inhibitory effects on LPS-induced inflammatory injury in chondrocytes. Taken together, these results demonstrate that ABIN-1 protects chondrocytes against LPS-induced inflammatory injury through the suppression of NF-κB signalling. Our study suggests a potential role for ABIN-1 in OA. Further, we show that ABIN-1 may serve as a potential target for controlling joint inflammation.

Osteoarthritis treatment with a novel nutraceutical acetylated ligstroside aglycone, a chemically modified extra-virgin olive oil polyphenol

Recent studies have shown that dietary patterns confer protection from certain chronic diseases related to oxidative stress, the immune system and chronic low-grade inflammatory diseases. The aim of this study was to evaluate the anti-inflammatory potential and the capacity to attenuate cartilage degradation using extra-virgin olive oil–derived polyphenols for the treatment of osteoarthritis. Results show that both nutraceuticals ligstroside aglycone and acetylated ligstroside aglycone showed an anti-inflammatory profile. Acetylated ligstroside aglycone significantly reduced the expression of pro-inflammatory genes including NOS2 and MMP13 at both RNA and protein levels; decreased nitric oxide release; and, importantly, reduced proteoglycan loss in human osteoarthritis cartilage explants. Our study demonstrated that a new synthetic acetylated ligstroside aglycone derivative offers enhanced anti-inflammatory profile than the natural nutraceutical compound in osteoarthritis. These results substantiate the role of nutraceuticals in osteoarthritis with implications for therapeutic intervention and our understanding of osteoarthritis pathophysiology.

Sustained acoustic medicine; sonophoresis for nonsteroidal anti-inflammatory drug delivery in arthritis

Background: Arthritis pain is primarily managed by nonsteroidal anti-inflammatory drugs (NSAIDs), such as diclofenac. Topical diclofenac gel is limited in efficacy due to its limited penetration through the skin. This study investigates the use of a multihour, wearable, localized, sonophoresis transdermal drug delivery device for the penetration enhancement of diclofenac through the skin. Materials & methods: A commercially available, sustained acoustic medicine (sam®) ultrasound device providing 4 h, 1.3 W, 132 mW/cm2, 3 MHz ultrasound treatment was evaluated for increasing the drug delivery of diclofenac gel through a human skin model and was compared with standard of care topical control diclofenac gel. Results: Sonophoresis of the diclofenac gel for 4 h increases diclofenac delivery by 3.8× (p < 0.01), and penetration by 32% (p < 0.01). Conclusion: Sustained acoustic medicine can be used as a transdermal drug-delivery device for nonsteroidal anti-inflammatory drugs.

Stachydrine attenuates IL-1β-induced inflammatory response in osteoarthritis chondrocytes through the NF-κB signaling pathway

Osteoarthritis (OA) is a common degenerative joint disease that is closely associated with inflammation. Stachydrine (STA) is a bioactive alkaloid with anti-inflammatory activity. However, the role of STA in OA remains unknown. This study aimed to explore the effects of STA on OA chondrocytes in the presence of IL-1β. Primary human OA chondrocytes were pretreated with various concentrations of STA for 2 h and then stimulated with IL-1β for 24 h. Inflammatory mediators and cytokines including NO, PGE2, TNF-α and IL-6 in chondrocytes were detected to reflect inflammation status. Production of extracellular matrix (ECM) degrading enzymes including MMP-3, MMP-13, ADAMTS-4 and ADAMTS-5 in chondrocytes was measured using ELISA. The expression levels of iNOS, COX-2, p65, p-p65, p-IκBα, and IκBα were detected by Western blot analysis. Our results showed that STA significantly suppressed IL-1β-induced inflammation with decreased levels of inflammatory mediators and cytokines including NO, PGE2, iNOS, COX-2, TNF-α and IL-6. Treatment with STA suppressed the production of ECM degrading enzymes including MMP-3, MMP-13, ADAMTS-4, and ADAMTS-5 in IL-1β-induced chondrocytes. Furthermore, STA blocked the IL-1β-mediated potentiation of NF-κB pathway in chondrocytes. In conclusion, these findings demonstrated that STA protected chondrocytes from IL-1β-induced inflammation through the NF-κB signaling pathway.

Anti-Inflammatory Activity of Miodesin™: Modulation of Inflammatory Markers and Epigenetic Evidence

PURPOSE

To investigate the effects of a combined herbal medicine Miodesin™ on the inflammatory response of key cells involved in the acute and chronic inflammatory processes as well as the possible epigenetic involvement.

METHODS

After the establishment of the IC50 dose, the chondrocyte, keratinocyte, and macrophage cell lines were pretreated for 2 hours with Miodesin™ (200 μg/mL) and stimulated with LPS (1 μg/mL) for 24 hours. The supernatant was used to measure the levels of cytokines (IL-1β, IL-6, IL-8, and TNF-α) and chemokines (CCL2, CCL3, and CCL5), and the cells were used to extract the mRNA for the transcription factor (NF-κβ), inflammatory enzymes (COX-1, COX-2, PLA2, and iNOS), and chemokines (CCL2, CCL3, and CCL5).

RESULTS

Miodesin™ inhibited the release of LPS-induced cytokines (IL-1β, IL-6, IL-8, and TNF-α; p < 0.01) and chemokines (CCL2, CCL3, and CCL5; p < 0.01) and the expression of the transcription factor (NF-κβ; p < 0.01), inflammatory enzymes (COX-1, COX-2, PLA2, iNOS; p < 0.01), and chemokines (CCL2, CCL3, and CCL5; p < 0.01). In addition, the evaluation of epigenetic mechanism revealed that Miodesin™ did not induce changes in DNA methylation, assuring the genetic safeness of the compound in terms of the inflammatory response.

CONCLUSIONS

Miodesin™ presents anti-inflammatory properties, inhibiting hyperactivation of chondrocytes, keratinocytes, and macrophages, involving epigenetics in such effects.

Impact of miR-SNP rs2910164 on miR-146a expression in osteoarthritic chondrocytes

PURPOSE

MiR-146a acts as a negative inflammatory mediator in different diseases and has been implicated in osteoarthritis (OA) pathogenesis. In our study, we investigated the association between miR-SNP rs2910164 and OA susceptibility and its role on the expression of miR-146a, inflammatory and catabolic mediators in osteoarthritic chondrocytes.

MATERIALS AND METHODS

Genetic association analysis was performed in 1688 knee OA patients and healthy individuals of Greek origin. Genomic DNA was extracted from blood and genotyped for rs2910164 (G > C) using Restriction-Fragment Length Polymorphism (RFLP). Total RNA was extracted from chondrocytes of 18 OA patients and miR-146a, IL-1 Receptor-Associated Kinase 1 (IRAK-1), TNF Receptor-Associated Factor 6 (TRAF-6), A Disintegrin and Metalloproteinase with Thrombospondin Motifs 5 (ADAMTS-5), Matrix Metalloproteinase-13 (MMP-13), Interleukin-6 (IL-6), Interleukin-1 Beta (IL-1β) and Tumor Necrosis Factor-Alpha (TNF-α) expression was evaluated using quantitative Real-Time PCR (qRT-PCR).

RESULTS

OA patients carrying rs2910164-GC and CC genotypes did not have an increased risk for OA development compared to GG genotype carriers. MiR-146a expression in OA chondrocytes was significantly lower in patients with rs2910164-GC genotype than in the GG carriers. OA patients carrying the rs2910164-GC genotype in their chondrocytes exhibited increased IRAK-1, TRAF-6, MMP-13, IL-1β and IL-6 expression levels compared with rs2910164-GG carriers.

CONCLUSION

We demonstrate, for the first time, that miR-SNP rs2910164 in miR-146a gene is associated with reduced miR-146a and increased inflammatory and catabolic mediators' expression in OA chondrocytes. Our data imply that genetic variations in miRNAs linked to OA pathogenesis may regulate their expression levels, suggesting new therapeutic strategies for patients with cartilage diseases.

Ingenuity pathway analysis of human facet joint tissues: Insight into facet joint osteoarthritis

Facet joint osteoarthritis (FJOA) is a common degenerative joint disorder with high prevalence in the elderly. FJOA causes lower back pain and lower extremity pain, and thus severely impacts the quality of life of affected patients. Emerging studies have focused on the histomorphological and histomorphometric changes in FJOA. However, the dynamic genetic changes in FJOA have remained to be clearly determined. In the present study, previously obtained RNA deep sequencing data were subjected to an ingenuity pathway analysis (IPA) and canonical signaling pathways of differentially expressed genes (DEGs) in FJOA were studied. The top 25 enriched canonical signaling pathways were identified and canonical signaling pathways with high absolute values of z-scores, specifically leukocyte extravasation signaling, Tec kinase signaling and osteoarthritis pathway, were investigated in detail. DEGs were further categorized by disease, biological function and toxicity (tox) function. The genetic networks between DEGs as well as hub genes in these functional networks were also investigated. It was demonstrated that C-X-C motif chemokine ligand 8, elastase, neutrophil expressed, growth factor independent 1 transcriptional repressor, Spi-1 proto-oncogene, CCAAT enhancer binding protein epsilon, GATA binding protein 1, TAL bHLH transcription factor 1, erythroid differentiation factor, minichromosome maintenance complex component 4, BTG anti-proliferation factor 2, BRCA1 DNA repair-associated, cyclin D1, chromatin assembly factor 1 subunit A, triggering receptor expressed on myeloid cells 1 and tumor protein p63 were hub genes in the top 5 IPA networks (with a score >30). The present study provides insight into the pathological processes of FJOA from a genetic perspective and may thus benefit the clinical treatment of FJOA.

Anti‑inflammatory and anti‑catabolic effect of non‑animal stabilized hyaluronic acid and mesenchymal stem cell‑conditioned medium in an osteoarthritis coculture model

Previous clinical studies have reported the clinical effectiveness of non‑animal stabilized hyaluronic acid (NASHA) and adipose‑derived mesenchymal stromal/stem cells (MSC) in the treatment of knee osteoarthritis (OA). Unlike MSC secreted mediators, in vitro anti‑inflammatory effects of NASHA have not been evaluated. We aimed to evaluate and compare the anti‑inflammatory effect of NASHA and MSC conditioned medium (stem cell‑conditioned medium; SC‑CM), in an explant‑based coculture model of OA. Cartilage and synovial membrane from seven patients undergoing total knee arthroplasty were used to create a coculture system. Recombinant IL‑1β was added to the cocultures to induce inflammation. Four experimental groups were generated: i) Basal; ii) IL‑1β; iii) NASHA (NASHA + IL‑1β); and iv) SC‑CM (SC‑CM + IL‑1β). Glycosaminoglycans (GAG) released in the culture medium and of nitric oxide (NO) production were quantified. Gene expression in cartilage and synovium of IL‑1β, matrix metallopeptidase 13 (MMP13), ADAM metallopeptidase with thrombospondin type 1 motif 5 (ADAMTS5) and tissue inhibitor of metalloproteinases 1 (TIMP1) was measured by reverse transcription‑quantitative PCR. Media GAG concentration was decreased in cocultures with NASHA and SC‑CM (48 h, P<0.05; 72 h, P<0.01) compared with IL‑1β. Production of NO was significantly lower only in SC‑CM after 72 h (P<0.01). In cartilage, SC‑CM inhibited the expression of IL‑1β, MMP13 and ADAMTS5, while NASHA had this effect only in MMP13 and ADAMTS5. In synovium, SC‑CM decreased the expression level of MMP13 and ADAMTS5, while NASHA only decreased ADAMTS5 expression. Both NASHA and SC‑CM increased TIMP1 expression in cartilage and synovium. Treatments with NASHA and SC‑CM were shown to be a therapeutic option that may help counteract the catabolism produced by the inflammatory state in knee OA. The anti‑inflammatory mediators produced by MSC promote a lower expression of inflammatory targets in our study model.

TET2 is involved in DNA hydroxymethylation, cell proliferation and inflammatory response in keratinocytes

DNA methylation and hydroxymethylation are the most common epigenetic modifications associated with the cell cycle and the inflammatory response. The present study aimed to investigate the role of 5-hydroxymethyl-cytosine (5-hmC) and ten-eleven translocation-2 (TET2) in keratinocytes. Following TET2 knockdown, dot blot analysis was performed to assess the levels of 5-hmC in keratinocytes, using HaCaT cells. Subsequently, the viability and cell cycle of HaCaT cells were assessed by MTT, Cell Counting Kit-8 assay and flow cytometric assays. Cyclin-dependent kinase inhibitor 2A and proinflammatory cytokine protein and mRNA expression levels were also detected. The present results suggested that TET2 may play an important role in regulating cellular proliferation by mediating DNA hydroxymethylation in HaCaT cells. In addition, TET2 knockdown decreased the production of proinflammatory cytokines, including lipocalin 2, S100 calcium binding protein A7, matrix metallopeptidase 9, C-X-C motif chemokine ligand 1, interferon regulatory factor 7 and interleukin-7 receptor. The present study suggested that TET2 regulated cell viability, apoptosis and the expression of inflammatory mediators in keratinocytes. Collectively, the results indicated that TET2 knockdown may relieve inflammatory responses in the skin.

Grape seed procyanidins suppress the apoptosis and senescence of chondrocytes and ameliorates osteoarthritis via the DPP4-Sirt1 pathway

Osteoarthritis (OA) is a complicated pathological condition affecting thousands of people around world, many with substantial unmet medical care needs and without any effective therapies.

Substantive molecular and histological changes within the meniscus with tears

BACKGROUND

The meniscus plays a vital role in the normal biomechanics of the knee. However, it is not well studied at the molecular level. The purpose of this study was to determine whether molecular and pathological changes in the meniscal tissue vary depending on the presence or absence of meniscal and/or anterior cruciate ligament tear (ACL).

METHODS

Six normal menisci (group A), seven simple torn menisci (group B) and seven torn menisci with concomitant anterior cruciate ligament tears (group C) were collected. We observed the pathological changes in the menisci and used real-time polymerase chain reaction along with immunohistochemistry and in situ hybridisation to examine the levels of ACAN, ADAMTS5, COL10A1, CEBPβ, MMP13 and miR-381-3p, miR-455-3p, miR-193b-3p, miR-92a-3p, respectively. Patients were scored preoperatively and postoperatively using the Lysholm Knee Scoring Scale and International Knee Documentation Committee Subjective Knee Evaluation Form.

RESULTS

Compared with group A, the expression levels of ADAMTS5, COL10A1, CEBPβ, and MMP13 and all the miRNAs were increased while ACAN was down-regulated in groups B and C. Additionally, the gene expression and miRNA levels were higher in group C than that in group B, except for ACAN, which was lower. Several fibrochondrocytes strongly expressed ADAMTS5, CEBPβ, and MMP13 in groups B and C and had high levels of miR-381-3p and miR-455-3p than that in group A. Postoperative Lysholm and IKDC scores were higher in group B than in group C.

CONCLUSIONS

Our findings suggest that the meniscus tended to degenerate after it was injured, especially when combined with a torn ACL. The miRNAs investigated in this study might also contribute to meniscus degeneration. Patients with a combined injury patterns might have relatively worse joint function.

Inhibition of Long Non-coding RNA CTD-2574D22.4 Alleviates LPS-induced Apoptosis and Inflammatory Injury of Chondrocytes

Background:

Osteoarthritis (OA) is a common joint disease characterized by cartilage degeneration. Long non-coding RNAs (lncRNAs) have been associated with inflammatory diseases, including OA. Here, we investigated the potential molecular role of lncRNAs in OA pathogenesis.

Methods:

ATDC5 cells were treated with lipopolysaccharides (LPS), and qPCR was used to identify and determine expression of potential lncRNAs involved in LPS-induced chondrocyte injury. Cell viability, apoptosis, and expression of cartilage-related genes and inflammatory cytokines were assessed after CTD-2574D22.4 knockdown.

Results:

After LPS stimulation, CTD-2574D22.4 was found to be the second highest up-regulated gene, and the enhanced expression was validated in OA chondrocytes. Moreover, CTD-2574D22.4 inhibition significantly rescued cell viability, suppressed by LPS stress, and markedly attenuated LPS-induced apoptosis. The expression of cartilage-degrading enzymes MMP-13 and ADAMTS-5 were increased, while type II collagen was reduced after LPS treatment. This trend was largely reversed by CTD-2574D22.4 knockdown. Additionally, mRNA and protein levels of key inflammatory cytokines (TNF-a, IL-6, and IL-1β) were significantly elevated in the LPS group and partially relieved upon CTD-2574D22.4 knockdown.

Conclusion:

CTD2574D22.4 knockdown ameliorates LPS-induced cartilage injury by protecting chondrocytes from apoptosis via anti-inflammation and anti- cartilage-degrading pathways. Thus, CTD2574D22.4 might be a potential diagnostic and therapeutic target for OA.

DAla2GIP antagonizes H2O2-induced chondrocyte apoptosis and inflammatory factor secretion

OBJECTIVE

To investigate the protective effects of DAla2GIP against the apoptosis and inflammatory factor secretion in H₂O₂-induced chondrocyte, and explore the possible mechanisms of DAla2GIP underlying its protection.

METHODS

The chondrocytes were divided into the following four groups: Control, 300 μM H₂O₂, 100 pM DAla2GIP and 300 μM H₂O₂ + 100 pM DAla2GIP. The apoptosis of chondrocyte was measured by using mitochondrial membrane potential assay kit (JC-1) and TUNEL assay, the inflammatory factor secretion were assessed by ELISA assay, and the cellular and molecular mechanisms of DAla2GIP protection were investigated by using Real time-PCR, flow cytometry, Non- invasive calcium detection and western blotting techniques.

RESULTS

(1) DAPla2GIP prevents apoptosis of chondrocyte induced by H₂O₂. (2) DAla2GIP alleviated the inflammation of chondrocyte induced by H₂O₂. (3) DAla2GIP prevents chondrocyte apoptosis by inhibiting calcium influx of chondrocyte and regulating expression of Bcl-2 and Caspase-3induced by H₂O₂. (4) DAla2GIP inhibited the H₂O₂ mediated inflammation by up- regulating the expressions of Sox9 and Col2a1 and inhibiting PI3K/Akt/NF-κB pathway.

CONCLUSION

Our experimental results revealed that DAla2GIP prevents chondrocyte apoptosis by inhibiting calcium influx of chondrocyte and induced regulating expression of Bcl-2 and Casp ase-3by H₂O₂. Further, molecular biology experiments confirmed that DAla2GIP inhibited the H₂O₂ mediated inflammation vis up-regulating the expressions of Sox9 and Col2a1 and inhibiting PI3K/Akt/NF-κB pathway. The results demonstrate that DAla2GIP has protective properties in H₂O₂-induced chondrocyte injury, this finding shows that novel GIP analogues have the potential as a novel therapeutic for osteoarthritis patients.