Search Results (522)

Osteoarthritis (OA), a degenerative joint disease primarily affecting the hips and knees, is characterized by multifactorial dysregulation of chondrocyte homeostasis and currently lacks curative treatment options. Intra-articular hyaluronic acid (HA) injections have clinically provided symptomatic relief for three decades; however, HA’s rapid in vivo degradation by free radicals and hyaluronidases limits its efficacy. We hypothesized that adding niacinamide (vitamin B3) to linear HA hydrogels would provide ancillary anti-inflammatory and anti-catabolic properties, thereby improving HA-based viscosupplementation therapy. This preliminary preclinical mechanistic study investigated the functional effects of incorporating niacinamide into linear HA-based hydrogels using in vitro cellular models. Initially, Raw 264.7 macrophages and C28/I2 or SW1353 human chondrocytes were pre-treated with varying concentrations of HA/B3, with or without lipopolysaccharide (LPS) or interleukin-1β (IL-1β), respectively. Subsequently, pro-inflammatory and pro-catabolic markers were quantified biochemically. Results demonstrated that HA/B3 hydrogels exhibited enhanced functional stability compared to HA alone and possessed significant anti-inflammatory and anti-catabolic properties, without inducing cytotoxicity in either cell line. In Raw 264.7 macrophages, HA/B3 inhibited LPS-induced tumor necrosis factor-α (TNF-α) release and suppressed cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) protein expression. In vitro, HA/B3 hydrogels reduced IL-1β-induced IL-6 production in primary chondrocytes by 16% and suppressed PGE₂ concentration in both macrophages and chondrocytes by 60%, effects superior to HA alone. Finally, a rat primary articular chondrocyte model suggested slight anti-hypertrophic effects of HA/B3 in vitro. Collectively, these findings suggest that HA/B3 hydrogels possess anti-arthritic potential, highlighting a novel strategy for next-generation viscosupplement systems. Full article

Background/Objectives: Galectins contribute to the pathogenesis of osteoarthritis (OA) by amplifying inflammatory and catabolic signaling, yet targeted therapeutic approaches remain limited. Three Dimensional (3D) models offer a promising platform to study human OA pathophysiology and evaluate novel interventions. Methods: We established 3D pellet cultures derived from human OA chondrocytes to investigate galectin-induced extracellular matrix (ECM) remodeling and the chondroprotective potential of phytochemicals. OA pellets were stimulated with individual galectins (Gal-1, -3, -4, -8) or a Gal-1/-3/-8 mixture, followed by co-treatment with Brazilin, Diacerein, Quercetin, Resveratrol, or Avocado-Soybean Unsaponifiables (ASU). Morphological, histological, biochemical, and gene expression analyses were performed to assess tissue integrity and molecular responses. Results: Galectin treatment induced pronounced pellet shrinkage, matrix depletion, and upregulation of matrix-degrading enzymes (MMP-1, MMP-3, MMP-13, ADAMTS-4), while suppressing matrix synthesis markers (COL2A1, COL1A1), highlighting their cooperative catabolic effects. Co-treatment with phytochemicals conferred differential protection: Brazilin and Diacerein most consistently preserved pellet size, reduced matrix-degrading gene expression, and attenuated pro-MMP-13 secretion. Resveratrol restored histological matrix density but failed to suppress pro-MMP-13 secretion. Notably, no phytochemical fully restored COL2A1 expression under galectin-induced stress. Conclusions: Our study identifies Brazilin, Diacerein, and Resveratrol as promising modulators of galectin-driven cartilage degeneration and demonstrates the translational potential of patient-derived chondrogenic pellets as a human-relevant platform for preclinical drug evaluation in OA. The 3D culture effectively recapitulates key aspects of OA pathophysiology and offers a robust system to advance therapeutic discovery targeting ECM remodeling. Full article

Human airways maintain homeostasis through intricate cellular interactomes combining secretome-mediated signalling and mechanotransduction feedback loops. This review presents the first unified map of bidirectional mechanobiology–secretome interactions between airway epithelial cells (AECs), smooth muscle cells (ASMCs), and chondrocytes. We unify a novel three-component regulatory architecture: epithelium functioning as environmental activators, smooth muscle as mechanical actuators, and cartilage as calcium-dependent regulators. Critical mechanotransduction pathways, particularly YAP/TAZ signalling and TRPV4 channels, directly couple matrix stiffness to cytokine release, creating a closed-loop feedback system. During development, ASM-driven FGF-10 signalling and peristaltic contractions orchestrate cartilage formation and epithelial differentiation through mechanically guided morphogenesis. In disease states, these homeostatic circuits become pathologically dysregulated; asthma and COPD exhibit feed-forward stiffness traps where increased matrix rigidity triggers YAP/TAZ-mediated hypercontractility, perpetuating further remodelling. Aberrant mechanotransduction drives smooth muscle hyperplasia, cartilage degradation, and epithelial dysfunction through sustained inflammatory cascades. This system-level understanding of airway cellular networks provides mechanistic frameworks for targeted therapeutic interventions and tissue engineering strategies that incorporate essential mechanobiological signalling requirements. Full article

Optimal mechanical parameters for successful bone-healing remain unclear despite their critical influence on fracture outcomes, and the timing of post-surgery mobilization is still controversial despite many clinical observations and pre-clinical studies. In this bioreactor in vitro work, we investigate the effect of fundamental parameters such as timing, duration, and frequency of mechanical stimulation on the endochondral bone-healing paths, specifically on the hypertrophic chondrocyte differentiation of naïve human mesenchymal stromal cells (hMSCs). Human MSCs encapsulated in Gelatin-Methacryloyl hydrogels (GelMa) were subjected to three different 10% strain protocols: P1 (168 long-break cycles spread over 14 days), P2ce (cycle equivalent: 168 short-break cycles condensed in 42-min stimulation followed by 14 days free swelling), and P2te (time equivalent—14 days continuous stimulation, 80′640 short-break cycles). In the free-swelling control group, samples were cultured for 14 days without any mechanical stimulation. Our results confirmed that 10% strain induces a robust hypertrophic chondrocyte differentiation of naïve MSCs in all three tested protocols, as demonstrated by enlarged cell size, rounded morphology, robust upregulation of hypertrophic markers (COL10A1, MMP13, RUNX2, ALP), and reduced glycosaminoglycan production. Of particular interest, we show that P2ce (early short stimulation) was as effective as the two extended stimulation protocols, suggesting that initial mechanical signals are sufficient to trigger cell differentiation toward a hypertrophic chondrocyte phenotype that continues even after stimulation ceases. These in vitro findings provide crucial insights into the cellular basis of endochondral ossification during the early phase of loading and show a beneficial long-term effect of early mechanical stimulation. By demonstrating that the cellular mechanobiology of hypertrophic differentiation responds to brief early stimulation, our findings provide a scientific foundation to guide future in vivo investigations on how rehabilitation protocols could influence fracture healing. Full article

Osteoarthritis (OA) involves cartilage breakdown and inflammation. This study compares juvenile and OA chondrocytes in gene expression, metabolism, and kinase activity, and tests mechanical stimulation to better understand cartilage health and degeneration. Juvenile (jCH) and OA (pCH-OA) primary chondrocytes were mechanically stimulated using the Flexcell™ FX5K system. Gene expression, protein phosphorylation, and metabolism were analyzed pre- and post-stimulation. Principal component analysis and effect size analyses identified molecular and signaling differences. Gene expression revealed significant differences between jCH and pCH-OA, with COL1 and RUNX2 upregulated in jCH, and MMP3 and ACAN downregulated. PCA revealed distinct expression patterns and marker correlations. Cyclic tensile strain affected biomarkers such as RUNX2, IL8, TLR4, BMP2, and MMP1 in a cell type-specific manner. Metabolic profiling indicated lower ROS and NAD⁺/NADH, and higher glutamate, lactate, and formate, with changes primarily driven by mechanical stimulation rather than cell type. Protein analysis showed altered AKT, STAT3, and MAPK phosphorylation, reflecting different mechanotransduction in healthy versus OA chondrocytes. Juvenile and OA chondrocytes show distinct molecular, metabolic, and signaling profiles, with mechanical stimulation driving key biomarker and metabolic changes. These differences highlight altered mechanotransduction in OA, providing insights into cartilage degeneration and potential therapeutic targets. Full article

ADAM10 is a transmembrane metalloprotease that regulates diverse signalling functions via the shedding of membrane protein ectodomains, and is implicated in tumour development, including glioblastoma multiforme (GBM) and gastrointestinal (GI) cancers, where high ADAM10 expression is associated with poor prognosis. We assessed the role of ADAM10 by gene knockout (KO) in U251 GBM cells, and its effects on protein shedding and protein expression on cell proliferation and on the growth of tumour xenografts in mice. The growth of tumours was severely delayed, relative to modest effects on proliferation in vitro, suggesting roles particularly in the context of the tumour microenvironment (TME). Proteomics analysis of KO cell-conditioned medium showed decreased levels of known ADAM10 targets such as Notch and Eph receptors and ligands, as well as other proteins involved in cell–cell adhesion, migration, signalling, metabolism, differentiation, and development, including angiogenesis. KO cell and tumour lysate analysis also showed modulation of proteins associated with metabolic and catalytic activity, cell–matrix organisation and differentiation. Similar effects were also observed in the SW620 colon cancer model, indicating broader significance. Furthermore, expression of the associated protein sets also correlated with ADAM10 expression in human GBM and colon cancer specimens (TCGA datasets), indicating clinical relevance. Collagens and proteins associated with matrix deposition and fibril organisation were notably reduced in ADAM10 KO GBM tumours, and histology confirmed decreased collagen fibrils and blood vessels. Unexpectedly, increased chondrocyte differentiation was evident in ADAM10 KO U251 tumours, suggesting a role for ADAM10 in maintaining an undifferentiated phenotype in vivo. Together, our data indicate the importance of ADAM10 in diverse signalling mechanisms in tumours and the TME that promote tumour development. Full article

Endometrial tissue-derived mesenchymal stem/stromal cells (eMSCs) have potential therapeutic properties partially exerted via their secreted extracellular vesicles (EVs). eMSC-EVs contain cargos with regenerative and immunomodulatory properties. Specifically, the miRNA profile of CD146High eMSC-EVs has been shown to promote anti-inflammatory M2 macrophage polarization in vitro. Herein, we aimed to characterize the lncRNA profile of CD146High and CD146Low eMSC-EVs and further assess their immunomodulatory and anabolic therapeutic function in osteoarthritis (OA). We hypothesized that the CD146High eMSC-EVs lncRNA profile is enriched with potent anti-inflammatory and pro-anabolic cartilage effects when compared to the CD146Low eMSC-EVs lncRNA profile. Human endometrial tissue was collected, and the eMSCs were magnetically sorted to yield the CD146High and CD146Low eMSC subpopulations. The eMSC-EVs were isolated via ultracentrifugation and CD63 magnetic immunoselection methods and characterized by nanosight and flow cytometry analyses. Our results showed that CD146High eMSC-EVs display an lncRNA profile with both anabolic and catabolic features, exerting a more dynamic effect on chondrocyte gene expression than CD146Low eMSC-EVs, suggesting a potential benefit of using CD146High eMSC-EVs to attenuate the negative effects of inflammation in OA. CD146High eMSC-EVs also demonstrated greater endothelial repair capacity under inflammatory stress. In conclusion, cell-free CD146High eMSC-EV has therapeutic potential through its protective anti-inflammatory effects, warranting further pre-clinical investigation. Full article

Background and Objectives: Heterotopic ossification (HO) involves abnormal bone growth in soft tissues. Current treatments are ineffective and prone to adverse effects, suggesting the need for new HO therapies. Intramembranous bone growth is led by osteoblasts. Since osteoblastogenesis and adipogenesis are opposed and mutually controlled processes, this study aims to identify a new repurposed therapeutic tool to inhibit osteoblastogenesis through adipogenesis promotion. Methods: We performed docking experiments between peroxisome proliferator-activated receptor-γ and bone metabolism-affecting drugs, namely, thiazolidinediones (rosiglitazone, pioglitazone), indomethacin, and dexamethasone, to test tritherapy antiosteoblastogenic effect. Mouse mesenchymal stem cells (C3H10T1/2), human osteoblast-like cells (SaOS2 and primary preosteoblasts), and mouse chondrocytes (ATDC5) were differentiated in the presence of these compounds. The effects on osteoblastogenesis, adipogenesis, and endochondral ossification were analysed through marker gene expression via RT–qPCR. Additionally, primary human HO cells and a congenital HO patient were treated with the selected drug combination (P-tritherapy). Results: Tritherapy significantly and synergistically promoted the expression of an adipogenic marker (fatty acid-binding protein 4) and decreased the expression of an osteoblastogenic marker (osteopontin). In an endochondral ossification model, it reduced ossification markers (collagen-2α1) expression, and in HO cells, it increased adipogenesis markers’ expression. Clinically, P-tritherapy administration prompted bone resorption in a patient with progressive osseous heteroplasia. Conclusions: Tritherapy induced adipogenesis while inhibiting osteoblastogenesis and endochondral ossification, demonstrating its potential as a new therapeutic tool to prevent abnormal bone growth. These results were consistent with bone turnover modification observed in a congenital HO patient. This concordance underscores tritherapy potential for rapid and safe translation to prevent HO. Full article

Type II collagen (Col2), a crucial structural protein in hyaline cartilage, is essential for cartilage integrity and facilitating injury repair. However, research on recombinant type II collagen still faces many challenges, such as structure and yield, which limit the application of recombinant Col2 in biomedical fields. In this study, we achieved high-yield expression of full-length human Col2 (rhCol2) in CHO cells. The physical and chemical properties of rhCol2 were very close to native Col2, including molecular weight, triple helix structure, thermal stability and self-assembly capacity. Functional assays of primary chondrocytes have demonstrated that rhCol2 can effectively promote chondrocyte proliferation and increase the expression levels of cartilage-specific genes (Col2a1, Aggrecan, and Sox-9). Moreover, a cartilage defect model was surgically created in SD rats demonstrated that rhCol2 significantly enhanced cartilage repair, and the severity of the defect was assessed through histological and micro-CT analyses. Human chondrocytes were utilized to compare the effects of different collagens and verified through a series of functional experiments. In conclusion, these findings indicate that rhCol2 is an effective biomaterial and is expected to promote the application of recombinant collagen in the field of cartilage repair. Full article

Thiotaurine (2-aminoethane thiosulfonate) is a naturally occurring sulfur-based compound featuring a thiosulfonate group, enabling it to act as a biologically relevant donor of hydrogen sulfide (H₂S) through thiol-dependent persulfidation. H₂S levels are known to be reduced in individuals with osteoarthritis, where it plays roles in modulating inflammation, oxidative stress, and pain. This study investigated the anti-inflammatory effects of Thiotaurine in human primary chondrocytes exposed to a pro-inflammatory cytokine. Cells were pre-treated with Thiotaurine prior to stimulation with TNF-α, and the expression levels of key interleukins were assessed at both the mRNA and protein levels. TNF-α stimulation led to upregulation of IL-6, IL-8, and IL-1β, which was significantly attenuated by Thiotaurine pre-treatment. Additionally, immunofluorescence analysis showed that Thiotaurine inhibited the phosphorylation and nuclear translocation of p65, indicating suppression of NF-κB pathway activation. Persulfide detection assays confirmed an increase in intracellular persulfide levels following Thiotaurine treatment. In summary, due to its anti-inflammatory activity and ability to release H₂S, Thiotaurine emerges as a promising and potentially safe therapeutic option for osteoarthritis and other inflammation-related conditions. Full article

Extracellular vesicles (EVs) from mesenchymal stem cells hold therapeutic promise for inflammatory and degenerative diseases; however, limited delivery and targeting capabilities hinder their clinical use. In this study, we sought to enhance the anti-inflammatory and chondroprotective effects of EVs through CAP-LAMP2b (chondrocyte affinity peptide fused to an EV membrane protein) engineering and ADAMTS4 gene editing hybrid vesicle formation. Human umbilical cord MSCs (hUCMSCs) were characterized via morphology, immunophenotyping, and trilineage differentiation. EVs from control and CAP-LAMP2b-transfected hUCMSCs were fused with liposomes carrying CRISPR-Cas9 ADAMTS4 gRNA. DiI-labeled EV uptake was assessed via fluorescence imaging. CAP-LAMP2b was expressed in hUCMSCs and their EVs. EVs exhibited the expected size (~120 nm), morphology, and exosomal markers (CD9, CD63, CD81, HSP70). CAP-modified hybrid EVs significantly enhanced chondrocyte uptake compared to control EVs and liposomes. IL-1β increased ADAMTS4 expression, whereas CAP-LAMP2b-ADAMTS4 EVs, particularly clone SG3, reversed these effects by reducing ADAMTS4 and restoring aggrecan. Western blotting confirmed suppressed ADAMTS4 and elevated aggrecan protein. CAP-LAMP2b-ADAMTS4 EVs, therefore, showed superior uptake and therapeutic efficacy in inflamed chondrocytes, attenuating inflammatory gene expression and preserving matrix integrity. These results support engineered EVs as a promising cell-free approach for cartilage repair and osteoarthritis treatment. Full article

Background: Intervertebral disc degeneration (IVDD) is closely linked to low back pain (LBP), a leading cause of disability worldwide. IVDD is characterized by the loss of proteoglycans (PGs), extracellular matrix (ECM) degradation, and reduced hydration of the nucleus pulposus (NP). Extracellular vesicles (EVs) derived from human umbilical cord mesenchymal stem cells (hUC-MSCs) exhibit tissue repair and immunomodulatory effects and are emerging as promising cell-free therapeutics. Methods: We established a rat IVDD model via fluoroscopy-guided needle puncture of three consecutive coccygeal discs and confirmed degeneration through Alcian Blue and hematoxylin & eosin (H&E) staining. The gene expression of inflammatory and pain markers (ADRβ2, COMP, CXCL1, COX2, PPTA, MMP13, YKL40) was measured by qPCR. Subsequently, we implanted hUC-MSCs or EVs to evaluate their reparative potential. Results: Upregulation of inflammatory and pain genes in IVDD was associated with an immunomodulatory response. Tracking DiI-labelled hUC-MSCs and EVs revealed enhanced survival of hUC-MSCs, retention of EVs, and dispersion within rat tail discs; EVs showed greater retention than hUC-MSCs. Implanted EVs were internalized by NP cells and remained within degenerative IVDs. EVs passively diffused, accumulated at the injury site, interacted with host cells, and enhanced function, as shown by increased expression of human chondrocyte-related markers (SOX9, TGFβ1, TGFβ2, COL2) compared to hUC-MSC treatment. Histological analysis of two weeks post-transplantation showed NP cellular patterns resembling chondromas in treated discs. EVs integrated into and distributed within degenerated NP regions, with greater glycosaminoglycan (GAG) content. Conclusions: Overall, hUC-MSC EVs demonstrated superior regenerative capacity, supporting a safe, cell-free strategy for disc repair. Full article

Allogeneic chondrocyte therapies present an attractive alternative to existing autologous therapies for the repair of cartilage defects, enabling the selection of optimal donor cells and streamlined manufacturing processes. This study investigates the potential of juvenile chondrocytes derived from human infantile (aged 0–4 y) polydactyly digits and the iliac apophysis for cartilage repair using Good Manufacturing Practice bioreactor expansion. Iliac apophysis (n = 4) and polydactyly tissues (n = 4) were assessed histologically. Chondrocytes were isolated enzymatically and cultured using standard tissue culture plastic (TCP) methodology. Upon sufficient cell expansion, chondrocytes were seeded into the Quantum^® bioreactor system or onto TCP (±vitronectin coating). The manufactured chondrocytes growth rates, total cell yields, chondrogenic pellet forming capacity (GAG/DNA, histology), immunoprofiles (flow cytometry) and gene expression (RT-qPCR) were assessed. Equivalent chondrocyte numbers were isolated from polydactyly and iliac apophysis donors per wet weight of tissue. Quantum^®-expanded chondrocytes from both sources yielded comparable cell numbers; however, growth was slowed in the Quantum^® compared to TCP. Polydactyly and iliac apophysis-derived chondrocytes expressed chondrocyte cell surface markers (CD166, CD44, CD151, SOX9) and formed chondrogenic pellets. Quantum^® bioreactor expansion did not alter, gene expression or capacity to form glycosaminoglycans (GAGs (normalised to DNA content)) compared to matched TCP expansion. Juvenile cartilage donors are a promising chondrocyte source for the development of an allogeneic therapy. This novel study expanding juvenile chondrocytes in the Quantum^® GMP-compliant bioreactor suggests that culture conditions may need modification to improve growth, whilst retaining cartilage forming capacity. Full article

Background/Objectives: Human ovarian granulosa cells (hGCs) are crucial to ovarian follicle development and function, exhibiting multipotency and the ability to differentiate into neuronal cells, chondrocytes, and osteoblasts in vitro. 3,4,5,4′-tetramethoxystilbene (DMU-212) is a methylated derivative of resveratrol, a natural polyphenol found in grapes and berries, with a wide spectrum of biological activities, including notable anticancer properties. Interestingly, DMU-212 exhibits cytotoxic effects predominantly on cancer cells while sparing non-cancerous ones, and evidence suggests that similar to resveratrol, it may also promote hGC differentiation. This study aimed to investigate the effects of the liposomal formulation of this methylated resveratrol analog—lipDMU-212—on the osteogenic differentiation ability of hGCs in a primary three-dimensional cell culture model. Methods: lipDMU-212 was formulated using the thin-film hydration method. GC spheroids’ viability was evaluated after exposure to lipDMU-212, an osteoinductive medium, or both. Osteogenic differentiation was confirmed using Alizarin Red staining and quantified by measuring Alkaline Phosphatase (ALP) activity on days 1, 7, and 15. RNA sequencing (RNA-seq) was performed to explore molecular mechanisms underlying lipDMU-212-induced differentiation. Results: lipDMU-212 promoted osteogenic differentiation of hGCs in the 3D cell culture model, as evidenced by increased mineralization and a ~4-fold increase in ALP activity compared with the control. RNA-seq revealed up-regulation of genes related to cell differentiation and cellular identity. Furthermore, JUN (+2.82, p = 0.003), LRP1 (+2.06, p = 0.05), AXIN1 (+3.02, p = 0.03), and FYN (+3.30, p = 0.01) were up-regulated, indicating modulation of the Wnt/β-catenin signaling pathway, a key regulator of osteoblast differentiation. Conclusions: The ability of GCs to differentiate into diverse tissue-specific cell types underscores their potential in regenerative medicine. This study contributes to the understanding of lipDMU-212’s role in osteogenic differentiation and highlights its potential in developing future therapies for degenerative bone diseases. Full article

A subset of chondrocytes in various human cartilage tissues, including neoplastic, regenerative, and normal cartilage, expresses α-smooth muscle actin (α-SMA), a protein typically found in smooth muscle cells. These α-SMA-containing chondrocytes, termed myochondrocytes and myochondroblasts, may play important roles in cartilage physiology, regeneration, and structural integrity, particularly in auricular and articular cartilage. This review synthesizes current knowledge regarding the terminology, distribution, and biological significance of these cells across normal, osteoarthritic, transplanted, and neoplastic cartilage. We summarize key findings from immunohistochemical studies using markers such as S-100, α-SMA, and SOX9, along with ultrastructural confirmation of myofilament bundles via electron microscopy. Current evidence suggests that myochondrocytes exhibit enhanced regenerative potential and contribute to matrix remodeling. Furthermore, their presence reflects the inherent cellular heterogeneity of cartilage, potentially arising from transdifferentiation processes involving fibroblasts, mesenchymal stem cells, or chondroblasts. Finally, TGF-β1 and PDGF-BB are identified as a critical modulator of α-SMA expression and chondrocyte phenotype. A deeper understanding of nature and function of myochondrocytes and myochondroblasts may improve interpretations of cartilage pathology and inform strategies for tissue engineering and cartilage repair. This review highlights the need for further investigation into the molecular regulation and functional roles of these cells in both physiological and pathological contexts. Full article