Exercise following joint distraction inhibits muscle wasting and delays the progression of post-traumatic osteoarthritis in rabbits by activating PGC-1α in skeletal muscle.

OBJECTIVE: Muscle wasting frequently occurs following joint trauma. Previous research has demonstrated that joint distraction in combination with treadmill exercise (TRE) can mitigate intra-articular inflammation and cartilage damage, consequently delaying the advancement of post-traumatic osteoarthritis (PTOA). However, the precise mechanism underlying this phenomenon remains unclear. Hence, the purpose of this study was to examine whether the mechanism by which TRE following joint distraction delays the progression of PTOA involves the activation of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), as well as its impact on muscle wasting. METHODS: Quadriceps samples were collected from patients with osteoarthritis (OA) and normal patients with distal femoral fractures, and the expression of PGC-1α was measured. The hinged external fixator was implanted in the rabbit PTOA model. One week after surgery, a PGC-1α agonist or inhibitor was administered for 4 weeks prior to TRE. Western blot analysis was performed to detect the expression of PGC-1α and Muscle atrophy gene 1 (Atrogin-1). We employed the enzyme-linked immunosorbent assay (ELISA) technique to examine pro-inflammatory factors. Additionally, we utilized quantitative real-time polymerase chain reaction (qRT-PCR) to analyze genes associated with cartilage regeneration. Synovial inflammation and cartilage damage were evaluated through hematoxylin-eosin staining. Furthermore, we employed Masson's trichrome staining and Alcian blue staining to analyze cartilage damage. RESULTS: The decreased expression of PGC-1α in skeletal muscle in patients with OA is correlated with the severity of OA. In the rabbit PTOA model, TRE following joint distraction inhibited the expressions of muscle wasting genes, including Atrogin-1 and muscle ring finger 1 (MuRF1), as well as inflammatory factors such as interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) in skeletal muscle, potentially through the activation of PGC-1α. Concurrently, the production of IL-1ß, IL-6, TNF-α, nitric oxide (NO), and malondialdehyde (MDA) in the synovial fluid was down-regulated, while the expression of type II collagen (Col2a1), Aggrecan (AGN), SRY-box 9 (SOX9) in the cartilage, and superoxide dismutase (SOD) in the synovial fluid was up-regulated. Additionally, histological staining results demonstrated that TRE after joint distraction reduced cartilage degeneration, leading to a significant decrease in OARSI scores.TRE following joint distraction could activate PGC-1α, inhibit Atrogin-1 expression in skeletal muscle, and reduce C-telopeptides of type II collagen (CTX-II) in the blood compared to joint distraction alone. CONCLUSION: Following joint distraction, TRE might promote the activation of PGC-1α in skeletal muscle during PTOA progression to exert anti-inflammatory effects in skeletal muscle and joint cavity, thereby inhibiting muscle wasting and promoting cartilage regeneration, making it a potential therapeutic intervention for treating PTOA.

Exosomes derived from miR-146a-overexpressing fibroblast-like synoviocytes in cartilage degradation and macrophage M1 polarization: a novel protective agent for osteoarthritis?

Introduction: Pathological changes in the articular cartilage (AC) and synovium are major manifestations of osteoarthritis (OA) and are strongly associated with pain and functional limitations. Exosome-derived microRNAs (miRNAs) are crucial regulatory factors in intercellular communication and can influence the progression of OA by participating in the degradation of chondrocytes and the phenotypic transformation in the polarization of synovial macrophages. However, the specific relationships and pathways of action of exosomal miRNAs in the pathological progression of OA in both cartilage and synovium remain unclear. Methods: This study evaluates the effects of fibroblast-like synoviocyte (FLS)-derived exosomes (FLS-Exos), influenced by miR-146a, on AC degradation and synovial macrophage polarization. We investigated the targeted relationship between miR-146a and TRAF6, both in vivo and in vitro, along with the involvement of the NF-κB signaling pathway. Results: The expression of miR-146a in the synovial exosomes of OA rats was significantly higher than in healthy rats. In vitro, the upregulation of miR-146a reduced chondrocyte apoptosis, whereas its downregulation had the opposite effect. In vivo, exosomes derived from miR-146a-overexpressing FLSs (miR-146a-FLS-Exos) reduced AC injury and chondrocyte apoptosis in OA. Furthermore, synovial proliferation was reduced, and the polarization of synovial macrophages shifted from M1 to M2. Mechanistically, the expression of TRAF6 was inhibited by targeting miR-146a, thereby modulating the Toll-like receptor 4/TRAF6/NF-κB pathway in the innate immune response. Discussion: These findings suggest that miR-146a, mediated through FLS-Exos, may alleviate OA progression by modulating cartilage degradation and macrophage polarization, implicating the NF-κB pathway in the innate immune response. These insights highlight the therapeutic potential of miR-146a as a protective agent in OA, underscoring the importance of exosomal miRNAs in the pathogenesis and potential treatment of the disease.

Knocking-down long non-coding RNA LINC01094 prohibits chondrocyte apoptosis via regulating microRNA-577/metal-regulatory transcription factor 1 axis.

PURPOSE: The abnormal function and survival of chondrocytes result in articular cartilage failure, which may accelerate the onset and development of osteoarthritis (OA). This study is aimed to investigate the role of LINC01094 in chondrocyte apoptosis. METHODS: The viability and apoptosis of lipopolysaccharide (LPS)-induced chondrocytes were evaluated through CCK-8 assay and flow cytometry analysis, respectively. The expression levels of LINC01094, miR-577 and MTF1 were detected by qRT-PCR. Dual luciferase reporter tests were implemented for the verification of targeted relationships among them. Western blotting was employed to measure the levels of pro-apoptotic proteins (Caspase3 and Caspase9). RESULTS: The viability of LPS-induced chondrocytes was overtly promoted by loss of LINC01094 or miR-577 upregulation, but could be repressed via MTF1 overexpression. The opposite results were observed in apoptosis rate and the levels of Caspase3 and Caspase9. LINC01094 directly bound to miR-577, while MTF1 was verified to be modulated by miR-577. Both LINC01094 and MTF1 were at high levels, whereas miR-577 was at low level in OA synovial fluid and LPS-induced chondrocytes. Furthermore, the highly expressed miR-577 abolished the influences of MTF1 overexpression on LPS-induced chondrocytes. CONCLUSIONS: Silencing of LINC01094 represses the apoptosis of chondrocytes through upregulating miR-577 expression and downregulating MTF1 levels, providing a preliminary insight for the treatment of OA in the future.

Integration of metabolomics and transcriptomics provides insights into the molecular mechanism of temporomandibular joint osteoarthritis.

The deficiency of clinically specific biomarkers has made it difficult to achieve an accurate diagnosis of temporomandibular joint osteoarthritis (TMJ-OA) and the insufficient comprehension of the pathogenesis of the pathogenesis of TMJ-OA has posed challenges in advancing therapeutic measures. The combined use of metabolomics and transcriptomics technologies presents a highly effective method for identifying vital metabolic pathways and key genes in TMJ-OA patients. In this study, an analysis of synovial fluid untargeted metabolomics of 6 TMJ-OA groups and 6 temporomandibular joint reducible anterior disc displacement (TMJ-DD) groups was conducted using liquid and gas chromatography mass spectrometry (LC/GC-MS). The differential metabolites (DMs) between TMJ-OA and TMJ-DD groups were analyzed through multivariate analysis. Meanwhile, a transcriptomic dataset (GSE205389) was obtained from the GEO database to analyze the differential metabolism-related genes (DE-MTGs) between TMJ-OA and TMJ-DD groups. Finally, an integrated analysis of DMs and DE-MTGs was carried out to investigate the molecular mechanisms associated with TMJ-OA. The analysis revealed significant differences in the levels of 46 DMs between TMJ-OA and TMJ-DD groups, of which 3 metabolites (L-carnitine, taurine, and adenosine) were identified as potential biomarkers for TMJ-OA. Collectively, differential expression analysis identified 20 DE-MTGs. Furthermore, the integration of metabolomics and transcriptomics analysis revealed that the tricarboxylic acid (TCA) cycle, alanine, aspartate and glutamate metabolism, ferroptosis were significantly enriched. This study provides valuable insights into the metabolic abnormalities and associated pathogenic mechanisms, improving our understanding of TMJOA etiopathogenesis and facilitating potential target screening for therapeutic intervention.

Extracellular vesicles from senescent mesenchymal stromal cells are defective and cannot prevent osteoarthritis.

Age is the most important risk factor in degenerative diseases such as osteoarthritis (OA), which is associated with the accumulation of senescent cells in the joints. Here, we aimed to assess the impact of senescence on the therapeutic properties of extracellular vesicles (EVs) from human fat mesenchymal stromal cells (ASCs) in OA. We generated a model of DNA damage-induced senescence in ASCs using etoposide and characterized EVs isolated from their conditioned medium (CM). Senescent ASCs (S-ASCs) produced 3-fold more EVs (S-EVs) with a slightly bigger size and that contain 2-fold less total RNA. Coculture experiments showed that S-ASCs were as efficient as healthy ASCs (H-ASCs) in improving the phenotype of OA chondrocytes cultured in resting conditions but were defective when chondrocytes were proliferating. S-EVs were also impaired in their capacity to polarize synovial macrophages towards an anti-inflammatory phenotype. A differential protein cargo mainly related to inflammation and senescence was detected in S-EVs and H-EVs. Using the collagenase-induced OA model, we found that contrary to H-EVs, S-EVs could not protect mice from cartilage damage and joint calcifications, and were less efficient in protecting subchondral bone degradation. In addition, S-EVs induced a pro-catabolic and pro-inflammatory gene signature in the joints of mice shortly after injection, while H-EVs decreased hypertrophic, catabolic and inflammatory pathways. In conclusion, S-EVs are functionally impaired and cannot protect mice from developing OA.

Dysregulation of Glypicans and Notum in Osteoarthritis: Plasma Levels, Bone Marrow Mesenchymal Stromal Cells and Osteoblasts.

In this study of the alterations of Glypicans 1 to 6 (GPCs) and Notum in plasma, bone marrow mesenchymal stromal cells (BM-MSCs) and osteoblasts in Osteoarthritis (OA), the levels of GPCs and Notum in the plasma of 25 patients and 24 healthy subjects were measured. In addition, BM-MSCs from eight OA patients and eight healthy donors were cultured over a period of 21 days using both a culture medium and an osteogenic medium. Protein and gene expression levels of GPCs and Notum were determined using ELISA and qPCR at 0, 7, 14 and 21 days. GPC5 and Notum levels decreased in the plasma of OA patients, while the BM-MSCs of OA patients showed downexpression of GPC6 and upregulation of Notum. A decrease in GPC5 and Notum proteins and an increase in GPC3 were found. During osteogenic differentiation, elevated GPCs 2, 4, 5, 6 and Notum mRNA levels and decreased GPC3 were observed in patients with OA. Furthermore, the protein levels of GPC2, GPC5 and Notum decreased, while the levels of GPC3 increased. Glypicans and Notum were altered in BM-MSCs and during osteogenic differentiation from patients with OA. The alterations found point to GPC5 and Notum as new candidate biomarkers of OA pathology.

Combinatory Nanovesicle with siRNA-Loaded Extracellular Vesicle and IGF-1 for Osteoarthritis Treatments.

Extracellular vesicles (EVs) have been found to have the characteristics of their parent cells. Based on the characteristics of these EVs, various studies on disease treatment using mesenchymal stem cell (MSC)-derived EVs with regenerative activity have been actively conducted. The therapeutic nature of MSC-derived EVs has been shown in several studies, but in recent years, there have been many efforts to functionalize EVs to give them more potent therapeutic effects. Strategies for functionalizing EVs include endogenous and exogenous methods. In this study, human umbilical cord MSC (UCMSC)-derived EVs were selected for optimum OA treatments with expectation via bioinformatics analysis based on antibody array. And we created a novel nanovesicle system called the IGF-si-EV, which has the properties of both cartilage regeneration and long-term retention in the lesion site, attaching positively charged insulin-like growth factor-1 (IGF-1) to the surface of the UCMSC-derived Evs carrying siRNA, which inhibits MMP13. The downregulation of inflammation-related cytokine (MMP13, NF-kB, and IL-6) and the upregulation of cartilage-regeneration-related factors (Col2, Acan) were achieved with IGF-si-EV. Moreover, the ability of IGF-si-EV to remain in the lesion site for a long time has been proven through an ex vivo system. Collectively, the final constructed IGF-si-EV can be proposed as an effective OA treatment through its successful MMP13 inhibition, chondroprotective effect, and cartilage adhesion ability. We also believe that this EV-based nanoparticle-manufacturing technology can be applied as a platform technology for various diseases.

Glycosphingolipids in Osteoarthritis and Cartilage-Regeneration Therapy: Mechanisms and Therapeutic Prospects Based on a Narrative Review of the Literature.

Glycosphingolipids (GSLs), a subtype of glycolipids containing sphingosine, are critical components of vertebrate plasma membranes, playing a pivotal role in cellular signaling and interactions. In human articular cartilage in osteoarthritis (OA), GSL expression is known notably to decrease. This review focuses on the roles of gangliosides, a specific type of GSL, in cartilage degeneration and regeneration, emphasizing their regulatory function in signal transduction. The expression of gangliosides, whether endogenous or augmented exogenously, is regulated at the enzymatic level, targeting specific glycosyltransferases. This regulation has significant implications for the composition of cell-surface gangliosides and their impact on signal transduction in chondrocytes and progenitor cells. Different levels of ganglioside expression can influence signaling pathways in various ways, potentially affecting cell properties, including malignancy. Moreover, gene manipulations against gangliosides have been shown to regulate cartilage metabolisms and chondrocyte differentiation in vivo and in vitro. This review highlights the potential of targeting gangliosides in the development of therapeutic strategies for osteoarthritis and cartilage injury and addresses promising directions for future research and treatment.

An exploratory metabolomic study reveals the Dipsacus asper-Achyranthes bidentate herb pair against osteoarthritis by modulating imbalance in polyunsaturated fatty acids and energy metabolism.

Osteoarthritis (OA) is a degenerative joint disease primarily affecting the cartilage. The therapeutic potential of the Dipsacus asper-Achyranthes bidentate herb pair for OA has been acknowledged, yet its precise mechanism remains elusive. In this study, we conducted a comprehensive analysis of metabolomic changes and therapeutic outcomes in osteoarthritic rats, employing a gas chromatography-mass spectrometry-based metabolomics approach in conjunction with histopathological and biochemical assessments. The rats were divided into six groups: control, model, positive control, Dipsacus asper treated, Achyranthes bidentata treated, and herb pair treated groups. Compared to the model group, significant reductions in levels of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and iNOS were observed in the treated groups. Multivariate statistical analyses were employed to investigate metabolite profile changes in serum samples and identify potential biomarkers, revealing 45 differential biomarkers, with eighteen validated using standard substances. These analytes exhibited excellent linearity across a wide concentration range (R2>0.9990), with intra- and inter-day precision RSD values below 4.69% and 4.83%, respectively. Recoveries of the eighteen analytes ranged from 93.97% to 106.59%, with RSD values under 5.72%, underscoring the method's reliability. Treatment with the herbal pair effectively restored levels of unsaturated fatty acids such as linoleic acid and arachidonic acid, along with glucogenic amino acids. Additionally, levels of phosphoric acid and citric acid were reversed, indicating restoration of energy metabolism. Collectively, these findings highlight the utility of metabolomic analysis in evaluating therapeutic efficacy and elucidating the underlying molecular mechanisms of herb pairs in OA treatment.

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.

Down-regulation of long noncoding RNA HOXA11-AS nullifies the impact of microRNA-506-3p on chondrocytes proliferation and apoptosis in osteoarthritis.

OBJECTIVES: This study was directed towards exploring the impacts of lncRNA HOXA11-AS-mediated microRNA (miR)-506-3p on chondrocytes proliferation and apoptosis in osteoarthritis (OA). METHODS: The articular cartilages were provided by OA patients who received total knee arthroplasty, and Human Chondrocyte (HC)-OA (HCOA) was also attained. The miR-506-3p and HOXA11-AS expressions in articular cartilages from OA patients and HCOA cells were analyzed via qPCR. After gain- and loss-of-function assays in HCOA cells, MTT assay and flow cytometry (FC) were used for assessing cell viability and apoptosis, accordingly. The levels of PIK3CA, AKT, and mTOR as well as AKT and mTOR phosphorylation levels assessed using western blotting (WB). The targeting correlation of HOXA11-AS and miR-506-3p as well as miR-506-3p and PIK3CA was assessed through Dual-Luciferase Reporter gene Assay (DLRA). RESULT: The articular cartilages from OA patients and Human Chondrocyte (HC)-OA (HCOA) cells showed increased HOXA11-AS and decreased miR-506-3p. Mechanistically, HOXA11-AS was capable of binding to miR-506-3p to increase PIK3CA, the target gene of miR-506-3p. miR-506-3p suppression facilitated HCOA cell proliferation and reduced their apoptosis, which was nullified by further silencing HOXA11-AS or silencing PIK3CA. The down-regulation of HOXA11-AS disrupted the PI3K/AKT/mTOR pathway, which was counteracted by further miR-506-3p inhibition. CONCLUSION: The silencing of HOXA11-AS might block the PI3K/AKT/mTOR pathway through miR-506-3p up-regulation, thereby restricting HCOA cell proliferation and provoking apoptosis.

MiR-653-5p drives osteoarthritis pathogenesis by modulating chondrocyte senescence.

BACKGROUND: Due to the unclear pathogenesis of osteoarthritis (OA), effective treatment for this ailment is presently unavailable. Accumulating evidence points to chondrocyte senescence as a key driver in OA development. This study aims to identify OA-specific microRNAs (miRNAs) targeting chondrocyte senescence to alleviate OA progression. METHODS: We screened and identified miRNAs differentially expressed in OA and normal cartilage, then confirmed the impact of miR-653-5p on chondrocyte functions and senescence phenotypes through in vitro experiments with overexpression/silencing. We identified interleukin 6 (IL-6) as the target gene of miR-653-5p and confirmed the regulatory influence of miR-653-5p on the IL-6/JAK/STAT3 signaling pathway through gain/loss-of-function studies. Finally, we assessed the therapeutic efficacy of miR-653-5p on OA using a mouse model with destabilization of the medial meniscus. RESULTS: MiR-653-5p was significantly downregulated in cartilage tissues and chondrocytes from OA patients. Overexpression of miR-653-5p promoted chondrocyte matrix synthesis and proliferation while inhibiting chondrocyte senescence. Furthermore, bioinformatics target prediction and the luciferase reporter assays identified IL-6 as a target of miR-653-5p. Western blot assays demonstrated that miR-653-5p overexpression inhibited the protein expression of IL-6, the phosphorylation of JAK1 and STAT3, and the expression of chondrocyte senescence phenotypes by regulating the IL-6/JAK/STAT3 signaling pathway. More importantly, the cartilage destruction was significantly alleviated and chondrocyte senescence phenotypes were remarkably decreased in the OA mouse model treated by agomiR-653-5p compared to the control mice. CONCLUSIONS: MiR-653-5p showed a significant decrease in cartilage tissues of individuals with OA, leading to an upregulation of chondrocyte senescence phenotypes in the articular cartilage. AgomiR-653-5p emerges as a potential treatment approach for OA. These findings provide further insight into the role of miR-653-5p in chondrocyte senescence and the pathogenesis of OA.

Regulation of cytokine and chemokine expression by histone lysine methyltransferase MLL1 in rheumatoid arthritis synovial fibroblasts.

Histone lysine methylation is thought to play a role in the pathogenesis of rheumatoid arthritis (RA). We previously reported aberrant expression of the gene encoding mixed-lineage leukemia 1 (MLL1), which catalyzes methylation of histone H3 lysine 4 (H3K4), in RA synovial fibroblasts (SFs). The aim of this study was to elucidate the involvement of MLL1 in the activated phenotype of RASFs. SFs were isolated from synovial tissues obtained from patients with RA or osteoarthritis (OA) during total knee joint replacement. MLL1 mRNA and protein levels were determined after stimulation with tumor necrosis factor α (TNFα). We also examined changes in trimethylation of H3K4 (H3K4me3) levels in the promoters of RA-associated genes (matrix-degrading enzymes, cytokines, and chemokines) and the mRNA levels upon small interfering RNA-mediated depletion of MLL1 in RASFs. We then determined the levels of H3K4me3 and mRNAs following treatment with the WD repeat domain 5 (WDR5)/MLL1 inhibitor MM-102. H3K4me3 levels in the gene promoters were also compared between RASFs and OASFs. After TNFα stimulation, MLL1 mRNA and protein levels were higher in RASFs than OASFs. Silencing of MLL1 significantly reduced H3K4me3 levels in the promoters of several cytokine (interleukin-6 [IL-6], IL-15) and chemokine (C-C motif chemokine ligand 2 [CCL2], CCL5, C-X-C motif chemokine ligand 9 [CXCL9], CXCL10, CXCL11, and C-X3-C motif chemokine ligand 1 [CX3CL1]) genes in RASFs. Correspondingly, the mRNA levels of these genes were significantly decreased. MM-102 significantly reduced the promoter H3K4me3 and mRNA levels of the CCL5, CXCL9, CXCL10, and CXCL11 genes in RASFs. In addition, H3K4me3 levels in the promoters of the IL-6, IL-15, CCL2, CCL5, CXCL9, CXCL10, CXCL11, and CX3CL1 genes were significantly higher in RASFs than OASFs. Our findings suggest that MLL1 regulates the expression of particular cytokines and chemokines in RASFs and is associated with the pathogenesis of RA. These results could lead to new therapies for RA.

Cbfß regulates Wnt/ß-catenin, Hippo/Yap, and Tgfß signaling pathways in articular cartilage homeostasis and protects from ACLT surgery-induced osteoarthritis.

As the most common degenerative joint disease, osteoarthritis (OA) contributes significantly to pain and disability during aging. Several genes of interest involved in articular cartilage damage in OA have been identified. However, the direct causes of OA are poorly understood. Evaluating the public human RNA-seq dataset showed that CBFB (subunit of a heterodimeric Cbfß/Runx1, Runx2, or Runx3 complex) expression is decreased in the cartilage of patients with OA. Here, we found that the chondrocyte-specific deletion of Cbfb in tamoxifen-induced Cbfbf/f;Col2a1-CreERT mice caused a spontaneous OA phenotype, worn articular cartilage, increased inflammation, and osteophytes. RNA-sequencing analysis showed that Cbfß deficiency in articular cartilage resulted in reduced cartilage regeneration, increased canonical Wnt signaling and inflammatory response, and decreased Hippo/Yap signaling and Tgfß signaling. Immunostaining and western blot validated these RNA-seq analysis results. ACLT surgery-induced OA decreased Cbfß and Yap expression and increased active ß-catenin expression in articular cartilage, while local AAV-mediated Cbfb overexpression promoted Yap expression and diminished active ß-catenin expression in OA lesions. Remarkably, AAV-mediated Cbfb overexpression in knee joints of mice with OA showed the significant protective effect of Cbfß on articular cartilage in the ACLT OA mouse model. Overall, this study, using loss-of-function and gain-of-function approaches, uncovered that low expression of Cbfß may be the cause of OA. Moreover, Local admission of Cbfb may rescue and protect OA through decreasing Wnt/ß-catenin signaling, and increasing Hippo/Yap signaling and Tgfß/Smad2/3 signaling in OA articular cartilage, indicating that local Cbfb overexpression could be an effective strategy for treatment of OA.

[Identification of Osteoarthritis Inflamm-Aging Biomarkers by Integrating Bioinformatic Analysis and Machine Learning Strategies and the Clinical Validation]. / ç”Ÿç‰©ä¿¡æ¯å­¦å’Œæœºå™¨å­¦ä¹ ç­–ç•¥è¯†åˆ«éª¨å ³èŠ‚ç‚Žç‚Žæ€§è¡°è€ç”Ÿç‰©æ ‡å¿—ç‰©ä¸Žä¸´åºŠéªŒè¯.

Objective: To identify inflamm-aging related biomarkers in osteoarthritis (OA). Methods: Microarray gene profiles of young and aging OA patients were obtained from the Gene Expression Omnibus (GEO) database and aging-related genes (ARGs) were obtained from the Human Aging Genome Resource (HAGR) database. The differentially expressed genes of young OA and older OA patients were screened and then intersected with ARGs to obtain the aging-related genes of OA. Enrichment analysis was performed to reveal the potential mechanisms of aging-related markers in OA. Three machine learning methods were used to identify core senescence markers of OA and the receiver operating characteristic (ROC) curve was used to assess their diagnostic performance. Peripheral blood mononuclear cells were collected from clinical OA patients to verify the expression of senescence-associated secretory phenotype (SASP) factors and senescence markers. Results: A total of 45 senescence-related markers were obtained, which were mainly involved in the regulation of cellular senescence, the cell cycle, inflammatory response, etc. Through the screening with the three machine learning methods, 5 core senescence biomarkers, including FOXO3, MCL1, SIRT3, STAG1, and S100A13, were obtained. A total of 20 cases of normal controls and 40 cases of OA patients, including 20 cases in the young patient group and 20 in the elderly patient group, were enrolled. Compared with those of the young patient group, C-reactive protein (CRP), interleukin (IL)-6, and IL-1ß levels increased and IL-4 levels decreased in the elderly OA patient group (P<0.01); FOXO3, MCL1, and SIRT3 mRNA expression decreased and STAG1 and S100A13 mRNA expression increased (P<0.01). Pearson correlation analysis demonstrated that the selected markers were associated with some indicators, including erythrocyte sedimentation rate (ESR), IL-1ß, IL-4, CRP, and IL-6. The area under the ROC curve of the 5 core aging genes was always greater than 0.8 and the C-index of the calibration curve in the nomogram prediction model was 0.755, which suggested the good calibration ability of the model. Conclusion: FOXO3, MCL1, SIRT3, STAG1, and S100A13 may serve as novel diagnostic biomolecular markers and potential therapeutic targets for OA inflamm-aging.

[Latest Findings on the Role of RUNX1 in Bone Development and Disorders]. / RUNX1åœ¨éª¨å‘è‚²åŠéª¨ç›¸å ³ç–¾ç— ä¸­çš„ä½œç”¨ç ”ç©¶è¿›å±•.

Runt-related transcription factor (RUNX1) is a transcription factor closely involved in hematopoiesis. RUNX1 gene mutation plays an essential pathogenic role in the initiation and development of hematological tumors, especially in acute myeloid leukemia. Recent studies have shown that RUNX1 is also involved in the regulation of bone development and the pathological progression of bone-related diseases. RUNX1 promotes the differentiation of mesenchymal stem cells into chondrocytes and osteoblasts and modulates the maturation and extracellular matrix formation of chondrocytes. The expression of RUNX1 in mesenchymal stem cells, chondrocytes, and osteoblasts is of great significance for maintaining normal bone development and the mass and quality of bones. RUNX1 also inhibits the differentiation and bone resorptive activities of osteoclasts, which may be influenced by sexual dimorphism. In addition, RUNX1 deficiency contributes to the pathogenesis of osteoarthritis, delayed fracture healing, and osteoporosis, which was revealed by the RUNX1 conditional knockout modeling in mice. However, the roles of RUNX1 in regulating the hypertrophic differentiation of chondrocytes, the sexual dimorphism of activities of osteoclasts, as well as bone loss in diabetes mellitus, senescence, infection, chronic inflammation, etc, are still not fully understood. This review provides a systematic summary of the research progress concerning RUNX1 in the field of bone biology, offering new ideas for using RUNX1 as a potential target for bone related diseases, especially osteoarthritis, delayed fracture healing, and osteoporosis.

CHMP5 attenuates osteoarthritis via inhibiting chondrocyte apoptosis and extracellular matrix degradation: involvement of NF-κB pathway.

BACKGROUND: Osteoarthritis (OA), the most common joint disease, is linked with chondrocyte apoptosis and extracellular matrix (ECM) degradation. Charged multivesicular body protein 5 (CHMP5), a member of the multivesicular body, has been reported to serve as an anti-apoptotic protein to participate in leukemia development. However, the effects of CHMP5 on apoptosis and ECM degradation in OA remain unclear. METHODS: In this study, quantitative proteomics was performed to analyze differential proteins between normal and OA patient articular cartilages. The OA mouse model was constructed by the destabilization of the medial meniscus (DMM). In vitro, interleukin-1 beta (IL-1ß) was used to induce OA in human chondrocytes. CHMP5 overexpression and silencing vectors were created using an adenovirus system. The effects of CHMP5 on IL-1ß-induced chondrocyte apoptosis were investigated by CCK-8, flow cytometry, and western blot. The effects on ECM degradation were examined by western blot and immunofluorescence. The potential mechanism was explored by western blot and Co-IP assays. RESULTS: Downregulated CHMP5 was identified by proteomics in OA patient cartilages, which was verified in human and mouse articular cartilages. CHMP5 overexpression repressed cell apoptosis and ECM degradation in OA chondrocytes. However, silencing CHMP5 exacerbated OA chondrocyte apoptosis and ECM degradation. Furthermore, we found that the protective effect of CHMP5 against OA was involved in nuclear factor kappa B (NF-κB) signaling pathway. CONCLUSIONS: This study demonstrated that CHMP5 repressed IL-1ß-induced chondrocyte apoptosis and ECM degradation and blocked NF-κB activation. It was shown that CHMP5 might be a novel potential therapeutic target for OA in the future.

Analgesic, Anti-Inflammatory, and Chondroprotective Activities of Siraitia grosvenorii Residual Extract.

Inflammation is crucial to osteoarthritis (OA) pathogenesis. The aim of this study was to evaluate Siraitia grosvenorii residue extract (NHGRE) obtained by extracting S. grosvenorii fruits with water as a potential food supplement for treating arthritis based on its analgesic, anti-inflammatory, and chondroprotective effects and the remaining residue with 70% ethanol. We observed the analgesic activity of NHGRE based on the acetic acid-induced writhing response in mice, examined its anti-inflammatory efficacy against carrageenan-induced paw oedema in mice, and investigated its effect on inflammatory cytokine expression in interleukin (IL)-1ß-induced SW1353 cells. Furthermore, we determined its effects on cartilage protection in interleukin-1ß (IL-1ß)-treated SW1353 cells. NHGRE at 200 mg/kg significantly reduced the acetic acid-induced writhing response and prevented oedema formation in the carrageenan-induced paw oedema model. In IL-1ß-induced SW1353 cells, NHGRE at 400 µg/mL reduced the expression of inflammation mediators such as tumour necrosis factor (TNF)-α (55.3%), IL-6 (35.4%), and prostaglandin E2 (PGE2) (36.9%) and down-regulated the expression of matrix metalloproteinase (MMP)-1 (38.6%), MMP-3 (29.3%), and MMP-13 (44.8%). Additionally, it restored degraded collagen II levels in chondrocytes. NHGRE plays a protective role in chondrocytes by regulating Nuclear factor kappa B (NF-κB) activation. Overall, NHGRE may be a useful therapeutic agent for OA by controlling pain, oedema formation, and inflammation-related mechanisms.

M2 Macrophage-Derived Extracellular Vesicles Encapsulated in Hyaluronic Acid Alleviate Osteoarthritis by Modulating Macrophage Polarization.

An imbalance between M1 and M2 macrophage polarization is critical in osteoarthritis (OA) development. We investigated the effect of M2 macrophage-derived extracellular vesicles (M2-EVs) to reprogramme macrophages from the M1 to M2 phenotype for OA treatment. M1 macrophages and mouse OA models were treated with M2-EVs. Proteomic analysis was performed to evaluate macrophage polarization in vitro. The OA models were as follows: destabilization of the medial meniscus (DMM) surgery-induced OA and collagenase-induced OA (CIOA). Hyaluronic acid (HA) was used to deliver M2-EVs. M2-EVs decreased macrophage accumulation, repolarized macrophages from the M1 to M2 phenotype, mitigated synovitis, reduced cartilage degradation, alleviated subchondral bone damage, and improved gait abnormalities in the CIOA and DMM models. Moreover, HA increased the retention time of M2-EVs and enhanced the efficiency of M2-EVs in OA treatment. Furthermore, proteomic analysis demonstrated that M2-EVs exhibited a macrophage reprogramming ability similar to IL-4, and the pathways might be the NOD-like receptor (NLR), TNF, NF-κB, and Toll-like receptor (TLR) signaling pathways. M2-EVs reprogrammed macrophages from the M1 to M2 phenotype, which resulted in beneficial effects on cartilage and attenuation of OA severity. In summary, our study indicated that M2-EV-guided reprogramming of macrophages is a promising treatment strategy for OA.

The Role of Copper-Induced M2 Macrophage Polarization in Protecting Cartilage Matrix in Osteoarthritis.

BACKGROUND The pathological mechanism of osteoarthritis is still unclear. The regulation of the immune microenvironment has been of growing interest in the progression and treatment of osteoarthritis. Macrophages with different phenotypes, producing different cytokines, have been linked to the mechanism of cartilage injury in osteoarthritis. Copper ions play a role in the immune response and are involved in the pathological mechanisms of osteoarthritis by affecting the metabolism of the cartilage matrix. Bioactive glass (BG) is an osteogenic material with superior biocompatibility. Here, we report on the regulatory behavior of macrophages using a copper-based composite BG material. MATERIAL AND METHODS Cu-BGC powder was prepared by sol-gel method, and scaffolds were fabricated and characterized using 3D printing. Macrophage cultures grown with Cu-BGC were examined for cell culture and proliferation. The effect of Cu-BGC on the degradation metabolism of chondrocytes, cultured in the environment of inflammatory cytokine IL-1ß, was determined. In addition, the morphology of macrophages, secretion of inflammatory cytokines, and expression of surface markers were examined. RESULTS The results show that Cu-BGC promotes macrophage proliferation at a range of concentrations and increases the secretion of anti-inflammatory cytokines while inhibiting proinflammatory cytokines. At the same time, M2-type cell surface markers are definitely expressed and the morphology of macrophages is altered. In addition, Cu-BGC inhibited the degradation metabolism of chondrocytes in the inflammatory environment induced by IL-1ß. CONCLUSIONS These results suggest that Cu-BGC induced macrophage polarization into an M2 type anti-inflammatory phenotype, and inhibition of immune injury response may play a role in delaying cartilage matrix damage in osteoarthritis.