Role of tenascin-C in articular cartilage

Aberrant methylation and expression of TNXB promote chondrocyte apoptosis and extracullar matrix degradation in hemophilic arthropathy via AKT signaling

Recurrent joint bleeding in hemophilia patients frequently causes hemophilic arthropathy (HA). Drastic degradation of cartilage is a major characteristic of HA, but its pathological mechanisms has not yet been clarified. In HA cartilages, we found server matrix degradation and increased expression of DNA methyltransferase proteins. We thus performed genome-wide DNA methylation analysis on human HA (N=5) and osteoarthritis (OA) (N=5) articular cartilages, and identified 1228 differentially methylated regions (DMRs) associated with HA. Functional enrichment analyses revealed the association between DMR genes (DMGs) and extracellular matrix (ECM) organization. Among these DMGs, Tenascin XB (TNXB) expression was down-regulated in human and mouse HA cartilages. The loss of Tnxb in F8-/- mouse cartilage provided a disease-promoting role in HA by augmenting cartilage degeneration and subchondral bone loss. Tnxb knockdown also promoted chondrocyte apoptosis and inhibited phosphorylation of AKT. Importantly, AKT agonist showed chondroprotective effects following Tnxb knockdown. Together, our findings indicate that exposure of cartilage to blood leads to alterations in DNA methylation, which is functionally related to ECM homeostasis, and further demonstrate a critical role of TNXB in HA cartilage degeneration by activating AKT signaling. These mechanistic insights allow development of potentially new strategies for HA cartilage protection.

Cartilage extracellular matrix-derived matrikines in osteoarthritis

Osteoarthritis (OA) is among the most frequent diseases of the musculoskeletal system. Degradation of cartilage extracellular matrix (ECM) is a hallmark of OA. During the degradation process, intact/full-length proteins and proteolytic fragments are released which then might induce different downstream responses via diverse receptors, therefore leading to different biological consequences. Collagen type II and the proteoglycan aggrecan are the most abundant components of the cartilage ECM. However, over the last decades, a large number of minor components have been identified and for some of those, a role in the manifold processes associated with OA has already been demonstrated. To date, there is still no therapy able to halt or cure OA. A better understanding of the matrikine landscape occurring with or even preceding obvious degenerative changes in joint tissues is needed and might help to identify molecules that could serve as biomarkers, druggable targets, or even be blueprints for disease modifying drug OA drugs. For this narrative review, we screened PubMed for relevant literature in the English language and summarized the current knowledge regarding the function of selected ECM molecules and the derived matrikines in the context of cartilage and OA.

Transcriptomic analyses of joint tissues during osteoarthritis development in a rat model reveal dysregulated mechanotransduction and extracellular matrix pathways

OBJECTIVE

Transcriptomic changes in joint tissues during the development of osteoarthritis (OA) are of interest for the discovery of biomarkers and mechanisms of disease. The objective of this study was to use the rat medial meniscus transection (MMT) model to discover stage and tissue-specific transcriptomic changes.

DESIGN

Sham or MMT surgeries were performed in mature rats. Cartilage, menisci and synovium were scored for histopathological changes at 2, 4 and 6 weeks post-surgery and processed for RNA-sequencing. Differentially expressed genes (DEG) were used to identify pathways and mechanisms. Published transcriptomic datasets from animal models and human OA were used to confirm and extend present findings.

RESULTS

The total number of DEGs was already high at 2 weeks (723 in meniscus), followed by cartilage (259) and synovium (42) and declined to varying degrees in meniscus and synovium but increased in cartilage at 6 weeks. The most upregulated genes included tenascins. The 'response to mechanical stimulus' and extracellular matrix-related pathways were enriched in both cartilage and meniscus. Pathways that were enriched in synovium at 4 weeks indicate processes related to synovial hyperplasia and fibrosis. Synovium also showed upregulation of IL-11 and several MMPs. The mechanical stimulus pathway included upregulation of the mechanoreceptors PIEZO1, PIEZO2 and TRPV4 and nerve growth factor. Analysis of data from prior RNA-sequencing studies of animal models and human OA support these findings.

CONCLUSION

These results indicate several shared pathways that are affected during OA in cartilage and meniscus and support the role of mechanotransduction and other pathways in OA pathogenesis.

Proteomic, mechanical, and biochemical development of tissue-engineered neocartilage

Background

The self-assembling process of cartilage tissue engineering is a promising technique to heal cartilage defects, preventing osteoarthritic changes. Given that chondrocytes dedifferentiate when expanded, it is not known if cellular expansion affects the development of self-assembled neocartilage. The objective of this study was to use proteomic, mechanical, and biochemical analyses to quantitatively investigate the development of self-assembled neocartilage derived from passaged, rejuvenated costal chondrocytes.

Methods

Yucatan minipig costal chondrocytes were used to create self-assembled neocartilage constructs. After 1, 4, 7, 14, 28, 56, or 84 days of self-assembly, constructs were analyzed through a variety of histological, biomechanical, biochemical, and proteomic techniques.

Results

It was found that temporal trends in neocartilage formation are similar to those seen in native hyaline articular cartilage development. For example, between days 7 and 84 of culture, tensile Young’s modulus increased 4.4-times, total collagen increased 2.7-times, DNA content decreased 69.3%, collagen type II increased 1.5-times, and aggrecan dropped 55.3%, mirroring trends shown in native knee cartilage. Importantly, collagen type X, which is associated with cartilage calcification, remained at low levels (≤ 0.05%) at all neocartilage developmental time points, similar to knee cartilage (< 0.01%) and unlike donor rib cartilage (0.98%).

Conclusions

In this work, bottom-up proteomics, a powerful tool to interrogate tissue composition, was used for the first time to quantify and compare the proteome of a developing engineered tissue to a recipient tissue. Furthermore, it was shown that self-assembled, costal chondrocyte-derived neocartilage is suitable for a non-homologous approach in the knee.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40824-022-00284-4.

Network analysis of synovial RNA sequencing identifies gene-gene interactions predictive of response in rheumatoid arthritis

BACKGROUND

To determine whether gene-gene interaction network analysis of RNA sequencing (RNA-Seq) of synovial biopsies in early rheumatoid arthritis (RA) can inform our understanding of RA pathogenesis and yield improved treatment response prediction models.

METHODS

We utilized four well curated pathway repositories obtaining 10,537 experimentally evaluated gene-gene interactions. We extracted specific gene-gene interaction networks in synovial RNA-Seq to characterize histologically defined pathotypes in early RA and leverage these synovial specific gene-gene networks to predict response to methotrexate-based disease-modifying anti-rheumatic drug (DMARD) therapy in the Pathobiology of Early Arthritis Cohort (PEAC). Differential interactions identified within each network were statistically evaluated through robust linear regression models. Ability to predict response to DMARD treatment was evaluated by receiver operating characteristic (ROC) curve analysis.

RESULTS

Analysis comparing different histological pathotypes showed a coherent molecular signature matching the histological changes and highlighting novel pathotype-specific gene interactions and mechanisms. Analysis of responders vs non-responders revealed higher expression of apoptosis regulating gene-gene interactions in patients with good response to conventional synthetic DMARD. Detailed analysis of interactions between pairs of network-linked genes identified the SOCS2/STAT2 ratio as predictive of treatment success, improving ROC area under curve (AUC) from 0.62 to 0.78. We identified a key role for angiogenesis, observing significant statistical interactions between NOS3 (eNOS) and both CAMK1 and eNOS activator AKT3 when comparing responders and non-responders. The ratio of CAMKD2/NOS3 enhanced a prediction model of response improving ROC AUC from 0.63 to 0.73.

CONCLUSIONS

We demonstrate a novel, powerful method which harnesses gene interaction networks for leveraging biologically relevant gene-gene interactions leading to improved models for predicting treatment response.

An updated view on Temporomandibular Joint degeneration: insights from the cell subsets of mandibular condylar cartilage

The high prevalence of temporomandibular joint osteoarthritis (TMJOA), which causes joint dysfunction, indicates the need for more effective methods for treatment and repair. Mandibular condylar cartilage (MCC), a typical fibrocartilage that experiences degenerative changes during the development of TMJOA, has become a research focus and therapeutic target in recent years. MCC is composed of four zones of cells at various stages of differentiation. The cell subsets in MCC exhibit different physiological and pathological characteristics during development and in TMJOA. Most studies of TMJOA are mainly concerned with gene regulation of pathological changes. The corresponding treatment targets with specific cell subsets in MCC may provide more accurate and reliable results for cartilage repair and TMJOA treatment. In this review, we summarized the current research progress on the cell subsets of MCC from the perspective of MCC development and degeneration. We hope to provide a reference for further exploration of the pathological process of TMJOA and improvement of TMJOA treatment.

TNIIIA2, The Peptide of Tenascin-C, as a Candidate for Preventing Articular Cartilage Degeneration

OBJECTIVE

TNIIIA2 is a peptide of the extracellular matrix glycoprotein tenascin-C. We evaluated whether intra-articular injection of TNIIIA2 could prevent articular cartilage degeneration without inducing synovitis in an osteoarthritis mice model.

DESIGN

Ten micrograms per milliliter of TNIIIA2 were injected into the knee joint of mice (group II) to evaluate the induction of synovitis. The control group received an injection of phosphate buffered saline (group I). Synovitis was evaluated using synovitis score 2 and 4 weeks after injection. The ligaments of knee joints of mice were transected to make the osteoarthritis model. After transection, 10 µg/mL of TNIIIA2 was injected into the knee joint (group IV). The control group received an injection of phosphate buffered saline after transection (group III). Histologic examinations were made using hematoxylin and eosin and safranin-O staining at 2, 4, 8, and 12 weeks postoperatively. An in vitro study was also performed to determine the mechanism by which TNIIIA2 prevents cartilage degeneration. Human chondrocytes were isolated, cultured, and treated with TNIIIA2. The expressions of various mRNAs, including inflammatory cytokines, and anabolic and catabolic factors for cartilage were compared using real-time polymerase chain reaction.

RESULTS

There were no differences between groups in the study of intra-articular injection of mice (group I vs. group II). In the osteoarthritis model, we found development of osteoarthritis was suppressed in group IV at 4 and 8 weeks. TNIIIA2 upregulated the expressions of tumor necrosis factor-α, matrix metalloproteinase 3, and basic fibroblast growth factor.

CONCLUSION

We demonstrated that TNIIIA2 could prevent cartilage degeneration without synovitis.

Tenascin-C-mediated suppression of extracellular matrix adhesion force promotes entheseal new bone formation through activation of Hippo signalling in ankylosing spondylitis

Objectives

The aim of this study was to identify the role of tenascin-C (TNC) in entheseal new bone formation and to explore the underlying molecular mechanism.

Methods

Ligament tissue samples were obtained from patients with ankylosing spondylitis (AS) during surgery. Collagen antibody-induced arthritis and DBA/1 models were established to observe entheseal new bone formation. TNC expression was determined by immunohistochemistry staining. Systemic inhibition or genetic ablation of TNC was performed in animal models. Mechanical properties of extracellular matrix (ECM) were measured by atomic force microscopy. Downstream pathway of TNC was analysed by RNA sequencing and confirmed with pharmacological modulation both in vitro and in vivo. Cellular source of TNC was analysed by single-cell RNA sequencing (scRNA-seq) and confirmed by immunofluorescence staining.

Results

TNC was aberrantly upregulated in ligament and entheseal tissues from patients with AS and animal models. TNC inhibition significantly suppressed entheseal new bone formation. Functional assays revealed that TNC promoted new bone formation by enhancing chondrogenic differentiation during endochondral ossification. Mechanistically, TNC suppressed the adhesion force of ECM, resulting in the activation of downstream Hippo/yes-associated protein signalling, which in turn increased the expression of chondrogenic genes. scRNA-seq and immunofluorescence staining further revealed that TNC was majorly secreted by fibroblast-specific protein-1 (FSP1)+fibroblasts in the entheseal inflammatory microenvironment.

Conclusion

Inflammation-induced aberrant expression of TNC by FSP1+fibroblasts promotes entheseal new bone formation by suppressing ECM adhesion forces and activating Hippo signalling.

Matrix reverses immortalization-mediated stem cell fate determination

Primary cell culture in vitro suffers from cellular senescence. We hypothesized that expansion on decellularized extracellular matrix (dECM) deposited by simian virus 40 large T antigen (SV40LT) transduced autologous infrapatellar fat pad stem cells (IPFSCs) could rejuvenate high-passage IPFSCs in both proliferation and chondrogenic differentiation. In the study, we found that SV40LT transduced IPFSCs exhibited increased proliferation and adipogenic potential but decreased chondrogenic potential. Expansion on dECMs deposited by passage 5 IPFSCs yielded IPFSCs with dramatically increased proliferation and chondrogenic differentiation capacity; however, this enhanced capacity diminished if IPFSCs were grown on dECM deposited by passage 15 IPFSCs. Interestingly, expansion on dECM deposited by SV40LT transduced IPFSCs yielded IPFSCs with enhanced proliferation and chondrogenic capacity but decreased adipogenic potential, particularly for the dECM group derived from SV40LT transduced passage 15 cells. Our immunofluorescence staining and proteomics data identify matrix components such as basement membrane proteins as top candidates for matrix mediated IPFSC rejuvenation. Both cell proliferation and differentiation were endorsed by transcripts measured by RNASeq during the process. This study provides a promising model for in-depth investigation of the matrix protein influence on surrounding stem cell differentiation.

Periodic injections of adipose-derived stem cell sheets attenuate osteoarthritis progression in an experimental rabbit model

Background

Subcutaneous adipose tissue represents an abundant source of multipotent adult stem cells named as Adipose-derived stem cells (ADSCs). With a cell sheet approach, ADSCs survive longer, and can be delivered in large quantities. We investigated whether intra-articular ADSC sheets attenuated osteoarthritis (OA) progression in a rabbit anterior cruciate ligament transection (ACLT) model.

Methods

Fabricating medium containing ascorbate-2-phosphate was used to enhance collagen protein secretion by the ADSCs to make ADSC sheets. At 4 weeks after ACLT, autologous ADSC sheets were injected intra-articularly into the right knee (ADSC sheets group), and autologous cell death sheets treated by liquid nitrogen were injected into the left knee (control group). Subsequent injections were administered once weekly. Femoral condyles were compared macroscopically and histologically.

Results

Macroscopically, OA progression was significantly milder in the ADSC sheets than in the control groups. Histologically, control knees showed obvious erosions in the medial and lateral condyles, while cartilage was retained predominantly in the ADSC sheets group. Immunohistochemically, MMP-1, MMP-13, ADAMTS-4 were less expressive in the ADSC sheets than in the control groups.

Conclusions

Periodic ADSC sheets injections inhibited articular cartilage degeneration without inducing any adverse effects. A large quantity of autologous ADSCs delivered by cell sheets homed to the synovium and protected chondrocytes.

Integrative Metabolic Pathway Analysis Reveals Novel Therapeutic Targets in Osteoarthritis

In osteoarthritis (OA), impairment of cartilage regeneration can be related to a defective chondrogenic differentiation of mesenchymal stromal cells (MSCs). Therefore, understanding the proteomic- and metabolomic-associated molecular events during the chondrogenesis of MSCs could provide alternative targets for therapeutic intervention. Here, a SILAC-based proteomic analysis identified 43 proteins related with metabolic pathways whose abundance was significantly altered during the chondrogenesis of OA human bone marrow MSCs (hBMSCs). Then, the level and distribution of metabolites was analyzed in these cells and healthy controls by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), leading to the recognition of characteristic metabolomic profiles at the early stages of differentiation. Finally, integrative pathway analysis showed that UDP-glucuronic acid synthesis and amino sugar metabolism were downregulated in OA hBMSCs during chondrogenesis compared with healthy cells. Alterations in these metabolic pathways may disturb the production of hyaluronic acid (HA) and other relevant cartilage extracellular matrix (ECM) components. This work provides a novel integrative insight into the molecular alterations of osteoarthritic MSCs and potential therapeutic targets for OA drug development through the enhancement of chondrogenesis.

Tenascin-C promotes the repair of cartilage defects in mice

BACKGROUND

The effects of tenascin-C (TNC) on cartilage repair were examined in cartilage defect model mice. An in vitro study was also performed to determine the mechanism of cartilage repair with TNC.

METHODS

Full-thickness osteochondral defects were filled with TNC (group A: 100 μg/ml, group B: 10 μg/ml, group C: empty). Mice were sacrificed at 1, 2, 3, and 6 weeks postoperatively. Cartilage repair was histologically evaluated using the modified WAKITANI score. Chondrocytes were isolated and cultured, and they were treated with TNC. The expressions of various mRNAs including TNC, inflammatory cytokines, and anabolic and catabolic factors for cartilage were compared by real-time polymerase chain reaction.

RESULTS

The defects in group A were covered with hyaline-like cartilage after 3 weeks. Average modified WAKITANI scores were significantly better in group A than in groups B and C at 3 and 6 weeks. TNC upregulated the expressions of endogenous TNC, inflammatory cytokines, and anabolic and catabolic factors for cartilage. TNC downregulated the expression of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 5.

CONCLUSIONS

Intra-articular injection of full-length TNC repaired cartilage in murine models of full-thickness osteochondral defects. TNC upregulated the expression of ADAMTS4, but downregulated the expression of ADAMTS5 that contributed to cartilage degradation.

Antibodies against nephronectin ameliorate anti-type II collagen-induced arthritis in mice

The extracellular matrix protein nephronectin (Npnt) is known to be critical for kidney development, but its function in inflammatory diseases is unknown. Here, we developed a new enzyme‐linked immunosorbent assay system to detect Npnt in various autoimmune diseases, which revealed that plasma Npnt levels are increased in various mouse autoimmune models. We also report that antibodies against the α8β1 integrin‐binding region of Npnt protect mice from anti‐type II collagen‐induced arthritis, suggesting that Npnt may be a potential therapeutic target molecule for the prevention of autoimmune arthritis.

Targeting early changes in the synovial microenvironment: a new class of immunomodulatory therapy?

Objectives

Controlled immune responses rely on integrated crosstalk between cells and their microenvironment. We investigated whether targeting proinflammatory signals from the extracellular matrix that persist during pathological inflammation provides a viable strategy to treat rheumatoid arthritis (RA).

Methods

Monoclonal antibodies recognising the fibrinogen-like globe (FBG) of tenascin-C were generated by phage display. Clones that neutralised FBG activation of toll-like receptor 4 (TLR4), without impacting pathogenic TLR4 activation, were epitope mapped by crystallography. Antibodies stained synovial biopsies of patients at different stages of RA development. Antibody efficacy in preventing RA synovial cell cytokine release, and in modulating collagen-induced arthritis in rats, was assessed.

Results

Tenascin-C is expressed early in the development of RA, even before disease diagnosis, with higher levels in the joints of people with synovitis who eventually developed RA than in people whose synovitis spontaneously resolved. Anti-FBG antibodies inhibited cytokine release by RA synovial cells and prevented disease progression and tissue destruction during collagen-induced arthritis.

Conclusions

Early changes in the synovial microenvironment contribute to RA progression; blocking proinflammatory signals from the matrix can ameliorate experimental arthritis. These data highlight a new drug class that could offer early, disease-specific immune modulation in RA, without engendering global immune suppression.