Expression In Chondrocytes Research Articles

Dimethyl Fumarate attenuates synovial inflammation, reduces nociception, and inhibits the development of post-traumatic osteoarthritis.

There is currently no cure or disease-modifying treatment for post-traumatic osteoarthritis (PTOA). This study aims to assess the efficacy of dimethyl fumarate (DMF), a US-FDA approved drug for multiple sclerosis, as a treatment for PTOA. PTOA was induced in male Lewis rats by medial meniscal transection (MMT) surgery, and DMF was intra-articularly administered once, one week following surgery. PTOA progression was evaluated using histological, molecular, and radiographic analyses, while secondary allodynia was measured longitudinally, and pain-related markers expression were analyzed in dorsal root ganglion (DRG). 3D radiographic imaging by µCT analysis revealed that DMF treatment attenuated cartilage degradation by decreasing cartilage lesions, surface roughness, and osteophyte formation in the proximal tibiae. Histological analysis showed that DMF markedly inhibited cartilage erosion and cartilage surface fibrillation. Gene expression and Luminex analysis indicated that DMF suppressed joint inflammation by inhibiting inflammatory cytokines. DMF mitigated allodynic pain behavior at 6 weeks and repressed pain mediator expression (Calca, Tac1, Trpv1) in lumbar DRGs. Additionally, DMF treatment inhibited inflammatory gene expression and cytokine secretion induced by IL1β stimulation of human articular chondrocytes in vitro. Mechanistically, DMF treatment reduced colony-stimulating factor 2 (CSF2 or GM-CSF) level in the synovial fluid in vivo and inhibited its expression in human OA chondrocytes. Furthermore, siRNA targeting of CSF2 reduced inflammatory gene expression in human chondrocytes. The findings suggest that DMF reduced inflammatory gene expression, inhibited cartilage degeneration, and mitigated PTOA development in rats. It also alleviated pain behavior indicating its potential as a disease-modifying therapy for PTOA.

Response eQTLs, chromatin accessibility, and 3D chromatin structure in chondrocytes provide mechanistic insight into osteoarthritis risk.

Osteoarthritis (OA) poses a significant healthcare burden with limited treatment options. While genome-wide association studies (GWASs) have identified over 100 OA-associated loci, translating these findings into therapeutic targets remains challenging. To address this gap, we mapped gene expression, chromatin accessibility, and 3D chromatin structure in primary human articular chondrocytes in both resting and OA-mimicking conditions. We identified thousands of differentially expressed genes, including those associated with differences in sex and age. RNA sequencing in chondrocytes from 101 donors across two conditions uncovered 3,782 unique eGenes, including 420 that exhibited strong and significant condition-specific effects. Colocalization with OA GWAS signals revealed 13 putative OA risk genes, 6 of which have not been previously identified. Chromatin accessibility and 3D chromatin structure provided insights into the mechanisms and conditional specificity of these variants. Our findings shed light on OA pathogenesis and highlight potential targets for therapeutic development.

Inhibition of ASIC1a reduces ferroptosis in rheumatoid arthritis articular chondrocytes via the p53/NRF2/SLC7A11 pathway.

The activation of acid-sensing ion channel 1a (ASIC1a) in response to extracellular acidification leads to an increase in extracellular calcium influx, thereby exacerbating the degeneration of articular chondrocytes in rheumatoid arthritis (RA). It has been suggested that the inhibition of extracellular calcium influx could potentially impede chondrocyte ferroptosis. The cystine transporter, solute carrier family 7 member 11 (SLC7A11), is recognized as a key regulator of ferroptosis. Recent studies suggest that the tumor suppressor gene p53 facilitates the induction of ferroptosis by suppressing the upregulation of SLC7A11. This process is mediated by the nuclear factor erythroid 2-related factor 2 (NRF2), a key transcription factor integral to the maintenance of cellular redox homeostasis and the regulation of inflammatory responses. This study aims to investigate the role of ASIC1a in the ferroptosis of RA chondrocytes and to determine the involvement of the p53/NRF2/SLC7A11 pathway in its underlying mechanism. Invitro experiments revealed that acidosis induces ferroptosis and reduces the expression of NRF2 and SLC7A11 in chondrocytes. Moreover, acidification significantly increased p53 protein levels in chondrocytes. Pifithrin-α (PFN-α), a p53 inhibitor, mitigated acidosis-induced ferroptosis and restored the diminished expression of NRF2 and SLC7A11. Furthermore, PcTx-1, an ASIC1a inhibitor, inhibited acidification-induced ferroptosis, enhanced the protein levels of SLC7A11 and NRF2, and reduced p53 expression. Invivo experiments demonstrated that the ASIC1a-specific inhibitor PcTx-1 ameliorated histopathological characteristics of ankle joints in collagen-induced arthritis (CIA) mice, decreased p53 expression, and enhanced NRF2 and SLC7A11 expression in chondrocytes. These findings suggest that ASIC1a inhibition may mitigate acidification-induced ferroptosis in articular chondrocytes in RA, potentially via the p53/NRF2/SLC7A11 pathway.

Single-Cell RNA sequencing reveals mitochondrial dysfunction in microtia chondrocytes

Microtia is a congenital malformation characterized by underdevelopment of the external ear. While chondrocyte dysfunction has been implicated in microtia, the specific cellular abnormalities remain poorly understood. This study aimed to investigate mitochondrial dysfunction in microtia chondrocytes using single-cell RNA sequencing. Cartilage samples were obtained from patients with unilateral, non-syndromic microtia and healthy controls. Single-cell RNA sequencing was performed using the 10 × Genomics platform. Bioinformatic analyses including cell type identification, trajectory analysis, and gene co-expression network analysis were conducted. Mitochondrial function was assessed through ROS levels, membrane potential, and transmission electron microscopy. Chondrocytes from microtia samples showed lower mitochondrial function scores compared to normal samples. Trajectory analysis revealed more disorganized differentiation patterns in microtia chondrocytes. Mitochondrial dysfunction in microtia chondrocytes was confirmed by increased ROS production, decreased membrane potential, and altered mitochondrial structure. Gene co-expression network analysis identified hub genes associated with mitochondrial function, including SDHA, SIRT1, and PGC1A, which showed reduced expression in microtia chondrocytes. This study provides evidence of mitochondrial dysfunction in microtia chondrocytes and identifies potential key genes involved in this process. These findings offer new insights into the pathogenesis of microtia and may guide future therapeutic strategies.

Sliding Hydrogels Reveal the Modulation of Mechanosensing Attenuates the Inflammatory Phenotype of Osteoarthritic Chondrocytes in 3D

ABSTRACTOsteoarthritis (OA) is a prevalen degenerative joint disease with no FDA‐approved therapies that can halt or reverse its progression. Current treatments address symptoms like pain and inflammation, but not underlying disease mechanisms. OA progression is marked by increased inflammation and extracellular matrix (ECM) degradation of the joint cartilage. While the role of biochemical cues has been widely studied for OA, how matrix mechanical cues influence OA phenotype remains poorly understood. Using sliding hydrogels (SGs) as a tool, we examine how local matrix compliance in 3D modulates OA chondrocyte phenotype and associated mechanosensing. We demonstrate that local matrix compliance reduces the inflammatory phenotype of OA chondrocytes, as indicated by decreased gene expression of catabolic markers and proinflammatory cytokine secretion. This is achieved via significantly reduced nuclear NF‐κB expression and signaling in OA chondrocytes. Live cell imaging shows enhanced cellular and nuclear dynamics with increased matrix deformation in the compliant SG. Blocking cellular dynamics negates SG compliance‐induced benefits in reducing OA inflammatory phenotype. Further, SG alters nuclear mechanosensing in OA as indicated by increased nuclear lamin reinforcement and chromatin condensation. Finally, we demonstrate that a drug inhibiting histone lysine demethylase to modulate chromatin accessibility reduces OA inflammation in 3D hydrogels. These findings advance our understanding of how ECM mechanics regulate OA mechanobiology and progression and highlight potential disease‐modifying treatments via epigenetic and mechanosensing‐based therapies.

Differential modulation of inflammatory cytokines by recombinant IL-10 in IL-1β and TNF-α ̶ stimulated equine chondrocytes and synoviocytes: impact of washing and timing on cytokine responses

Osteoarthritis (OA) remains a challenging joint disorder necessitating effective anti-inflammatory interventions. In this study, our primary objective was to establish an in vitro protocol that replicates the clinical investigation of anti-inflammatory drugs intended for OA management. Focusing on recombinant IL-10 (r.IL-10) as a potential anti-inflammatory treatment, we designed and implemented two distinct protocols to evaluate the efficacy of r.IL-10 in modulating chondrocyte and synoviocyte inflammation.The experimental design involved sequential stimulation with IL-1β and TNF-α for 24 h, followed by washing (model 1) or not washing (model 2) the cells before r.IL-10 treatment. Samples were collected after 6–24 h of treatment. Cellular responses were evaluated by quantifying gene expression and synthesis of key inflammatory cytokines and proteases.The expression and synthesis of inflammatory cytokines and proteases was significantly affected by washing and treatment time. The expression of IL-1β, TNF-α, IL-8, MMP-13, and ADAMTS5 were effectively reduced in r.IL-10-treated chondrocytes and synoviocytes in model 2 after 24 h, particularly at concentrations of 10 and 20 ng/mL. r.IL-10 treatment significantly increased IL-6 gene expression in chondrocytes at all time points. However, in synoviocytes, IL-6 expression was significantly lower in model 2 after 24 h of r.IL-10 treatment. r.IL-10 treatment significantly decreased IL-1β and TNF-α content in synoviocyte supernatants, particularly in model 2 at concentrations of 10 and 20 ng/mL after 6 and 24 h. r.IL-10 treatment in chondrocytes led to a significant decrease in IL-1β supernatant concentrations in model 2 after 24 h only.This study demonstrated that r.IL-10 treatment effectively reduces key inflammatory markers and matrix metalloproteinase activity in both chondrocytes and synoviocytes, particularly in model 2 where cells were not washed prior to treatment. These findings highlight r.IL-10’s potential as a robust anti-inflammatory agent for OA management and suggest its critical role in developing effective therapeutic strategies for OA.

Fibroblast growth factor 7 (FGF7) causes cartilage destruction, subchondral bone remodeling, and the premature growth plate closure in mice

ObjectiveFibroblast growth factor (FGF) signaling plays a significant role in osteoarthritis (OA) pathogenesis, though the OA-related functions of only a few FGFs have been fully elucidated. This study investigates the specific roles of FGF7 in OA development. MethodsFGF7 expression was analyzed in human (n=6) and mouse (n=10) cartilage. Experimental OA was induced by destabilization of the medial meniscus (DMM). The roles of FGF7 were explored using intra-articular (IA) injection of recombinant FGF7 (rFGF7) and whole-body Fgf7 knockout mice (Fgf7-/-). Subchondral bone remodeling and growth plate morphology were assessed microCT and histological analysis. ResultsFGF7 was upregulated in OA cartilage. IA injection of rFGF7 led to OA cartilage destruction (OARSI grade; 0.61 [95% CI 0.00–5.33]), while Fgf7-/- mice showed reduced DMM-induced cartilage erosion (OARSI grade; 1.89 [95% CI 1.08–3.00]) compared to WT mice (4.92 [95% CI 3.83–5.33]). These effects were associated with changes in matrix-degrading enzyme expression in chondrocytes. Mice receiving IA injection of rFGF7 (20 μg) exhibited increased subchondral bone thickness (68.01 μm [95% CI 61.55–74.46]) and decreased osteoclastogenesis (TRAP positivity; 1.94% [95% CI 1.41–2.47]) compared to controls (38.33 μm [95% CI 33.71–42.96]) and (4.23% [95% CI 3.28–5.19]), respectively. Additionally, rFGF7 treatment caused premature closure of growth plates, whereas Fgf7-/- mice exhibited significantly increased growth plate thickness. ConclusionsFGF7 exerts multiple functions in various joint tissues, including promoting cartilage destruction, inducing subchondral bone remodeling (SBP thickening), and triggering premature growth plate closure.

Change in p53 nuclear localization in response to extracellular matrix stiffness.

Chondrocytes are commonly applied in regenerative medicine and tissue engineering. Thus, the discovery of optimal culture conditions to obtain cells with good properties and behavior for transplantation is important. In addition to biochemical cues, physical and biomechanical changes can affect the proliferation and protein expression of chondrocytes. Here we investigated the effect of extracellular matrix stiffness on mouse articular chondrocyte phenotype, growth, and subcellular p53 localization. Chondrocytes were seeded on collagen-coated substrates varying in elasticity: 0.5 and 100kPa. Immunocytochemical staining and immunoblotting showed that a softer substrate significantly increased p53 nuclear localization in chondrocytes. Furthermore, we identified microRNA-532 (miR-532) as a potential p53 target gene to influence cell function, indicating a new target for tissue engineering. These findings provide insight into the influence of physical cues on cell phenotype maintenance and could help improve understanding of cartilage-related pathologies such as osteoarthritis.

Development of optimized standardized extracts of Echinodorus macrophyllus for arthritis management

Ethnopharmacological relevanceEchinodorus macrophyllus is a medicinal plant traditionally used in Brazil to treat rheumatic diseases. It is listed as a priority species for the development of herbal preparations for the Brazilian Unified Health System (SUS). Previous studies have demonstrated the anti-inflammatory and antiedematogenic properties of extracts and fractions from this species, but these preparations were neither standardized nor optimized for anti-arthritis effects. Aim of studyThis study aimed to investigate the anti-inflammatory and antiarthritic effects of various standardized extracts from the aerial parts of E. macrophyllus and to outline their mechanisms of action. The goal was to define an extract suitable for future scientific validation and clinical use. Material and methodsExtracts from the aerial parts of E. macrophyllus were prepared through percolation with 96°GL ethanol (EtOH) and hydroethanolic solutions at 90%, 70%, and 50% (v/v). They were standardized based on the contents of six chemical markers quantified by UPLC-DAD. Mice with acute or chronic antigen-induced arthritis (AIA) were treated with the extracts orally. The effects were evaluated by counting total and differential inflammatory cells, measuring cytokines by ELISA, and by histological analysis with toluidine blue staining. The mechanism of selected extracts was investigated in LPS-stimulated murine chondrocytes. ResultsAll extracts, except for the 90% EtOH extract, exhibited significant anti-inflammatory activity in acute AIA, reducing the migration of total inflammatory cells, neutrophils, and monocytes to the intra-articular cavity. In chronic AIA, both the 96°GL EtOH and 70% EtOH extracts markedly reduced the migration of total inflammatory cells, neutrophils, and monocytes to the intra-articular cavity, decreased IL-1β and CXCL1 levels in the periarticular tissue, and diminished proteoglycan loss in the articular cartilage. Both extracts reduced IL-6 release and MMP-3 expression in LPS-stimulated chondrocytes. The 70% EtOH and 50% EtOH extracts showed heightened activity and higher levels of chemical markers, notably cinnamoyl-tartaric acid derivatives. ConclusionsThe standardized 70% EtOH and 50% EtOH extracts from the aerial parts of E. macrophyllus, which contain higher levels of chemical markers, exhibit potent anti-inflammatory activity and reduce proteoglycan degradation. These extracts are potentially useful for developing herbal preparations to manage arthritic conditions and should be prioritized for further studies.

Protective mechanism of Prim-O-glucosylcimifugin in the treatment of osteoarthritis: Based on lncRNA XIST regulation of Nav1.7

LncRNA XIST and Nav1.7 have been identified to be significantly associated with the onset of osteoarthritis. Prim-O-glucosylcimifugin (POG) has antiinflammatory and analgesic effects in treating osteoarthritis (OA). However, its molecular mechanism of action remains unclear. This research investigated whether POG inhibits OA cartilage degeneration by regulating Nav1.7 through lncRNA XIST. We observed the relationship between lncRNA XIST and Nav1.7 through in vivo and in vitro experiments, and utilized lentiviral plasmids for XIST overexpression to further validate the protective effect of POG against OA. In vivo experiments revealed the close association of improving OA cartilage morphological changes by POG with lncRNA XIST and Nav1.7 downregulation and related proteins expression. In vitro experiments demonstrated significantly up-regulated lncRNA XIST and Nav1.7 expression in IL1β-induced chondrocytes, and their levels and related protein expression decreased after POG intervention. FISH indicated that POG attenuated the fluorescence intensity of lncRNA XIST in chondrocytes. RT-PCR and Western blot assays revealed the positive correlation of lncRNA XIST and Nav1.7 expression in chondrocytes. Additionally, flow cytometry results revealed that POG intervention reduced OA chondrocyte apoptosis. Therefore, we conclude that POG can mediate lncRNA XIST to regulate Nav1.7 to delay cartilage degeneration, which is an effective way to treat OA. However, lncRNA XIST is not the only target for regulation, and further discussion is needed.

Functional genomics of human skeletal development and the patterning of height heritability.

Underlying variation in height are regulatory changes to chondrocytes, cartilage cells comprising long-bone growth plates. Currently, we lack knowledge on epigenetic regulation and gene expression of chondrocytes sampled across the human skeleton, and therefore we cannot understand basic regulatory mechanisms controlling height biology. We first rectify this issue by generating extensive epigenetic and transcriptomic maps from chondrocytes sampled from different growth plates across developing human skeletons, discovering novel regulatory networks shaping human bone/joint development. Next, using these maps in tandem with height genome-wide association study (GWAS) signals, we disentangle the regulatory impacts that skeletal element-specific versus global-acting variants have on skeletal growth, revealing the prime importance of regulatory pleiotropy in controlling height variation. Finally, as height is highly heritable, and thus often the test case for complex-trait genetics, we leverage these datasets within a testable omnigenic model framework to discover novel chondrocyte developmental modules and peripheral-acting factors shaping height biology and skeletal growth.

Response eQTLs, chromatin accessibility, and 3D chromatin structure in chondrocytes provide mechanistic insight into osteoarthritis risk.

Osteoarthritis (OA) poses a significant healthcare burden with limited treatment options. While genome-wide association studies (GWAS) have identified over 100 OA-associated loci, translating these findings into therapeutic targets remains challenging. Integrating expression quantitative trait loci (eQTL), 3D chromatin structure, and other genomic approaches with OA GWAS data offers a promising approach to elucidate disease mechanisms; however, comprehensive eQTL maps in OA-relevant tissues and conditions remain scarce. We mapped gene expression, chromatin accessibility, and 3D chromatin structure in primary human articular chondrocytes in both resting and OA-mimicking conditions. We identified thousands of differentially expressed genes, including those associated with differences in sex and age. RNA-seq in chondrocytes from 101 donors across two conditions uncovered 3782 unique eGenes, including 420 that exhibited strong and significant condition-specific effects. Colocalization with OA GWAS signals revealed 13 putative OA risk genes, 10 of which have not been previously identified. Chromatin accessibility and 3D chromatin structure provided insights into the mechanisms and conditional specificity of these variants. Our findings shed light on OA pathogenesis and highlight potential targets for therapeutic development.

Role of IL3RA in a Family with Lumbar Spinal Stenosis.

Lumbar spinal stenosis (LSS) is a degenerative spinal condition characterized by the narrowing of the spinal canal, resulting in low back pain (LBP) and limited leg mobility. Twin and family studies have suggested that genetics contributes to disease progression. However, the genetic causes of familial LSS remain unclear. We performed whole-exome and direct sequencing on seven female patients from a Han Chinese family with LBP, among whom four developed LSS. Based on our genetic findings, we performed gene knockdown studies in human chondrocytes to study possible pathological mechanisms underlying LSS. We found a novel nonsense mutation, c.417C > G (NM_002183, p.Y139X), in IL3RA, shared by all the LBP/LSS cases. Knockdown of IL3RA led to a reduction in the total collagen content of 81.6% in female chondrocytes and 21% in male chondrocytes. The expression of MMP-1, -3, and/or -10 significantly increased, with a more pronounced effect observed in females than in males. Furthermore, EsRb expression significantly decreased following IL3RA knockdown. Moreover, the knockdown of EsRb resulted in increased MMP-1 and -10 expression in chondrocytes from females. We speculate that IL3RA deficiency could lead to a reduction in collagen content and intervertebral disk (IVD) strength, particularly in females, thereby accelerating IVD degeneration and promoting LSS occurrence. Our results illustrate, for the first time, the association between IL3RA and estrogen receptor beta, highlighting their importance and impact on MMPs and collagen in degenerative spines in women.

Exosomal microRNA-363 mediates the destructive effect of M1 macrophages on chondrocytes by repressing G3BP2

M1 polarization of synovial macrophages contributes to cartilage degeneration and osteoarthritis (OA) development. However, limited knowledge is available about how M1 macrophages affect the biological properties of chondrocytes. This study aimed to explore the role of exosomal microRNAs (miRs) released from M1 macrophages in modulating the proliferation and survival of chondrocytes. Through bioinformatic analysis and experimental validation, we indicated that miR-363 was selectively induced in M1 macrophages (CD68+CD80+) but not M2 macrophages (CD68+CD206+). The upregulation of miR-363 in M1 macrophages depended on the activation of STAT1 signaling. Clinically, OA patients had a significantly higher miR-363 level in synovial fluid than control individuals without OA. Functional studies revealed that inhibition of miR-363 blocked the M1 macrophage polarization induced by lipopolysaccharide and IFN-γ. Moreover, exosomal miR-363 released from M1 macrophages significantly suppressed the proliferation and survival and induced inflammatory gene expression in chondrocytes. G3BP2 was identified as a target gene for miR-363 and could be negatively regulated by miR-363. Knockdown of G3BP2 recapitulated the effect of miR-363 overexpression on chondrocytes. Most importantly, enforced expression of G3BP2 attenuated miR-363-induced apoptosis and inflammatory response in chondrocytes. In conclusion, miR-363 plays an indispensable role in M1 macrophage polarization and can be released from M1 macrophages via exosomes to cause chondrocyte injury and inflammation. The miR-363/G3BP2 axis may represent a promising target for the prevention of OA development.

Anti-Inflammatory and Antioxidant Effects of Irigenen Alleviate Osteoarthritis Progression through Nrf2/HO-1 Pathway.

Osteoarthritis (OA) is a prevalent degenerative disease globally, characterized by cartilage degradation and joint dysfunction. Current treatments are insufficient for halting OA progression. Irigenin (IRI), a flavonoid extracted from natural plants with anti-inflammatory and antioxidant properties, has demonstrated potential in mitigating inflammation and oxidative stress in various diseases; however, its effects on OA remain unexplored. This study aims to evaluate the therapeutic effects of IRI on OA through in vivo and in vitro experiments and to elucidate the underlying molecular mechanisms. In vitro, chondrocytes were exposed to hydrogen peroxide (H2O2) to induce an oxidative stress environment and were then treated with IRI. Western blotting, RT-qPCR, immunofluorescence staining assays, flow cytometry, and apoptosis assays were employed to assess the effects of IRI on chondrocyte matrix homeostasis, inflammatory response, and apoptosis. In vivo, an OA rat model was treated with regular IRI injections, and therapeutic effects were evaluated using micro-CT, histological staining, and immunohistochemistry assays. IRI treatment restored matrix homeostasis in chondrocytes and effectively suppressed H2O2-induced inflammation and apoptosis. Subsequent studies further revealed that IRI exerts its therapeutic effects by activating the Nrf2/HO-1 pathway. Inhibition of Nrf2 expression in chondrocytes partially blocked the anti-inflammatory and antioxidant effects of IRI. In the OA rat model, regular IRI injections effectively ameliorated cartilage degeneration. This study identifies IRI as a promising strategy for OA treatment by modulating inflammation and apoptosis through the Nrf2/HO-1 pathway.

A pH-responsive novel delivery system utilizing carbon quantum dots loaded with PT2385 for targeted inhibition of HIF-2α in the treatment of osteoarthritis

BackgroundOsteoarthritis (OA) is a progressive joint disorder marked by the degradation of cartilage. Elevated concentrations of hypoxia-inducible factor-2α (HIF-2α) are intricately linked to the pathological development of OA. PT2385 has demonstrated effective inhibition of HIF-2α, thereby potentially impeding the initial advancement of OA. Nevertheless, challenges persist, including limited penetration into the deeper layers of cartilage, issues related to charge rejection, and a heightened rate of clearance from the joint. These constraints necessitate further consideration and exploration. MethodsIt has been demonstrated that PT2385 exhibits efficient inhibition of HIF-2α expression, thereby contributing to the delay in the progression of osteoarthritis. The pH-responsive attributes of carbon quantum dots, specifically those employing m-phenylenediamine (m-CQDs) coated with bovine serum albumin (BSA), have been systematically evaluated. In both in vitro settings involving cartilage explants and in vivo experiments, the efficacy of BSA-m-CQDs-PT2385 (BCP) has been confirmed in facilitating the transport of PT2385 to the middle and deep layers of cartilage. Furthermore, the BCP system demonstrates controlled drug release contingent upon alterations in environmental pH. ResultsWhile the use of PT2385 alone provides protective effects on chondrocytes within an inflamed environment, there exists an opportunity for further enhancement in its efficacy when administered via intra-articular injection. The BCP formulation, characterized by appropriate particle size and charge, facilitates seamless penetration into cartilage tissue. Additionally, BCP demonstrates the capability to release drugs in response to changes in environmental pH. In vitro experiments reveal that BCP effectively inhibits Hif-2α expression and catabolic factors in chondrocytes. Notably, cartilage explants and in vivo experiments indicate that BCP surpasses PT2385 alone in inhibiting the expression of HIF-2α and matrix metalloproteinase 13, particularly in the middle and deep layers. ConclusionsThe BCP drug delivery system exhibits selective release of PT2385 in response to pH changes occurring during the progression of osteoarthritis (OA), thereby inhibiting HIF-2α expression deep within the cartilage. The use of BCP significantly augments the capacity of PT2385 to retard both cartilage degeneration and the progression of osteoarthritis. Consequently, BCP as an innovative approach utilizing m-CQDs to deliver PT2385 into articular cartilage, shows potential for treating osteoarthritis.This strategy opens new avenues for osteoarthritis treatment.

Efficacy and safety of SKCPT in patients with knee osteoarthritis: A multicenter, randomized, double-blinded, active-controlled phase III clinical trial

Ethnopharmacological relevanceOsteoarthritis (OA) is the most prevalent type of arthritis worldwide and a leading cause of years lost to pain and disability. Among the current pharmacological treatments for OA, symptomatic slow-acting drugs for OA (SYSADOA) induce pain relief and aim to improve joint function by relieving inflammation while causing fewer gastrointestinal and cardiovascular adverse events than non-steroidal anti-inflammatory drugs (NSAIDs). SKCPT is a herbal SYSADOA formulated from Clematis mandshurica, Trichosanthes kirilowii, and Prunella vulgaris powdered extracts. This preparation has been shown to induce cartilage protection and anti-inflammatory effects in preclinical studies and inhibit glycosaminoglycan degradation and catabolic gene expression in human OA chondrocytes and cartilage. Aim of the studyWe aimed to evaluate the non-inferiority of SKCPT to celecoxib and safety for treating knee OA. Materials and methodsThis multicenter, randomized, double-blind, phase III clinical trial enrolled adults with primary knee OA who were randomized (1:1) to SKCPT 300 mg twice daily or celecoxib 200 mg once daily for 12 weeks. ResultsIn total, 278 patients were assigned to treatment (SKCPT, 136; celecoxib, 142) for approximately 12 weeks. The primary endpoint was the mean change of Korean Western Ontario and McMaster Universities Osteoarthritis Index (K-WOMAC) pain subscale scores from baseline to Day 84. The mean change (least squares [LS] mean ± standard error) from baseline to Day 84 was −23.74 ± 1.48 for SKCPT and −25.88 ± 1.44 for celecoxib. The two-sided 95% confidence interval of the difference (LS mean) between groups was [−1.94, 6.20], confirming that the upper limit was less than the non-inferiority margin of 10. Additionally, there were no significant differences in the secondary endpoints (mean changes of K-WOMAC pain, physical, stiffness subscale, and total score, and the frequency and number of doses of rescue medications) between groups at all time points. Differences between groups in adverse events and adverse drug reactions were not significant, and no serious adverse events occurred. ConclusionsSKCPT efficacy was non-inferior, and its safety profile was similar, to celecoxib. Building on previous results showing that SYSADOA reduce NSAID intake, the present results suggest that the SYSADOA SKCPT could effectively replace NSAIDs in knee OA treatment while avoiding long-term side effects.

Myrislignan ameliorates the progression of osteoarthritis: An in vitro and in vivo study

Osteoarthritis (OA) is a prevalent disease of the musculoskeletal system that causes functional deterioration and diminished quality of life. Myrislignan (MRL) has a wide range of pharmacological characteristics, including an anti-inflammatory ability. Although inflammation is a major cause of OA, the role of MRL in OA treatment is still not well-understood. In this study, we analyze the anti-inflammatory and anti-ECM degradation effects of MRL both in vivo and in vitro. Rat primary chondrocytes were treated with interleukin-1β (IL-1β) to simulate inflammatory environmental conditions and OA in vitro. The in vivo OA rat model was established by anterior cruciate ligament transection (ACLT) on rat. Our investigation discovered that MRL lowers the IL-1β-activated tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX2) and inducible nitric-oxide synthase (iNOS) expression in chondrocytes. Moreover, MRL effectively alleviates IL-1β-induced extracellular matrix (ECM) degradation and promotes ECM synthesis in chondrocytes by upregulating the mRNA level expression of collagen-II and aggrecan (ACAN), downregulating the expression of matrix metalloproteinases-3,-13 (MMP-3, MMP-13), and a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS-5). Gene expression profiles of different groups identified DEGs that were mainly enriched in functions associated with NF-κB signaling pathway, and other highly enriched in functions related to TNF, IL-17, Rheumatoid arthritis and cytokine-cytokine receptor signaling pathways. Venn interaction of DEGs from the abovementioned five pathways showed that Nfkbia, Il1b, Il6, Nfkb1, Ccl2, Mmp3 were highly enriched DEGs. In addition, our research revealed that MRL suppresses NF-κB and modulates the Nrf2/HO-1/JNK signaling pathway activated by IL-1β in chondrocytes. In vivo research shows that MRL slows the progression of OA in rats. Our findings imply that MRL might be a viable OA therapeutic choice.

Syndecan-4 inhibition attenuates cartilage degeneration in temporomandibular joint osteoarthritis.

Syndecan 4 (SDC4), a type I transmembrane proteoglycan, serves as a critical link between chondrocytes and the extracellular matrix. This study aimed to explore the role of SDC4 in cartilage degeneration of temporomandibular joint osteoathritis (TMJOA). Condylar chondrocytes were stimulated with varying concentrations of recombinant rat interleukin-1β (rrIL-1β) and SDC4 small interfering RNA (si-SDC4). Anti-SDC4 ectodomain-specific antibodies or IgG were intra-articularly administrated in a TMJOA model rats. SDC4 conditional knockout (SDC4-cKO) and Sdc4flox/flox mice were induced TMJOA. Cartilage degeneration was assessed using haematoxylin & eosin (H&E) and safranin O (SO) staining. Protein levels of SDC4, matrix metalloproteinases (MMPs), a disintegrin and metalloproteinase with a thrombospondin motifs 5 (ADAMTS5), tumour necrosis factor α (TNFα), type II collagen (Col-II), aggrecan (ACAN), cleaved caspase 3 (CASP3), Ki67 and related pathways in condylar cartilage were evaluated by immunohistochemical (IHC) staining or western blot assays. SDC4 expression was evidently increased in MIA-model animals compared to control groups. rrIL-1β stimulation increased the expression of SDC4, MMP3 and ADAMTS5 expression in chondrocytes, while decreasing the expression of Col-II. These effects were reversed by si-SDC4 invitro. Invivo, SDC4 blockade reduced the death of chondrocytes and the loss of cartilage matrix, which was evidenced by increased expression of Col-II and ACAN, and a decrease in SDC4, MMP13 and cleaved-CASP3-positive cells. Furthermore, the protein levels of ACAN and Ki67 were elevated, and the ERK1/2 and P38 signalling pathways were activated following SDC4 inhibition. SDC4 inhibition significantly ameliorates condylar cartilage degeneration, which was mediated, at least partly, through P38 and ERK1/2 signalling. Inhibition of SDC4 may be of great value for the treatment of TMJOA.

ELIXCYTE®, an Allogenic Adipose-Derived Stem Cell Product, Mitigates Osteoarthritis by Reducing Inflammation and Preventing Cartilage Degradation In Vitro.

Adipose-derived stem cells (ADSCs) comprise a promising therapy for osteoarthritis (OA). The therapeutic potential of ELIXCYTE®, an allogeneic human ADSC (hADSC) product, was demonstrated in a phase I/II OA clinical trial. However, the exact mechanism underlying such effects is not clear. Moreover, studies suggest that interleukin-11 (IL-11) has anti-inflammatory, tissue-regenerative, and immune-regulatory functions. Our aim was to unravel the mechanism associated with the therapeutic effects of ELIXCYTE® on OA and its relationship with IL-11. We cocultured ELIXCYTE® with normal human articular chondrocytes (NHACs) in synovial fluid obtained from individuals with OA (OA-SF) to investigate its effect on chondrocyte matrix synthesis and degradation and inflammation by assessing gene expression and cytokine levels. NHACs exposed to OA-SF exhibited increased MMP13 expression. However, coculturing ELIXCYTE® with chondrocytes in OA-SF reduced MMP13 expression in chondrocytes and downregulated PTGS2 and FGF2 expression in ELIXCYTE®. ELIXCYTE® treatment elevated anti-inflammatory cytokine (IL-1RA, IL-10, and IL-13) levels, and the reduction in MMP13 was positively correlated with IL-11 concentrations in OA-SF. These findings indicate that IL-11 in OA-SF might serve as a predictive biomarker for the ELIXCYTE® treatment response in OA, emphasizing the therapeutic potential of ELIXCYTE® to mitigate OA progression and provide insights into its immunomodulatory effects.