Modulation of TGF-beta signaling by proinflammatory cytokines in articular chondrocytes

Self-assembled peptide-substance P hydrogels alleviate inflammation and ameliorate the cartilage regeneration in knee osteoarthritis

BACKGROUND

Self-assembled peptide (SAP)-substance P (SP) hydrogels can be retained in the joint cavity longer than SP alone, and they can alleviate inflammation and ameliorate cartilage regeneration in knee osteoarthritis (OA). We conducted a preclinical study using diverse animal models of OA and an in vitro study using human synoviocytes and patient-derived synovial fluids to demonstrate the effect of SAP-SP complex on the inflammation and cartilage regeneration.

METHODS

Surgical induction OA model was prepared with New Zealand white female rabbits and chemical induction, and naturally occurring OA models were prepared using Dunkin Hartely female guinea pigs. The SAP-SP complex or control (SAP, SP, or saline) was injected into the joint cavities in each model. We performed micro-computed tomography (Micro-CT) analysis, histological evaluation, immunofluorescent analysis, and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling (TUNEL) assay and analyzed the recruitment of intrinsic mesenchymal stem cells (MSCs), macrophage activity, and inflammatory cytokine in each OA model. Human synoviocytes were cultured in synovial fluid extracted from human OA knee joints injected with SAP-SP complexes or other controls. Proliferative capacity and inflammatory cytokine levels were analyzed.

RESULTS

Alleviation of inflammation, inhibition of apoptosis, and enhancement of intrinsic MSCs have been established in the SAP-SP group in diverse animal models. Furthermore, the inflammatory effects on human samples were examined in synoviocytes and synovial fluid from patients with OA. In this study, we observed that SAP-SP showed anti-inflammatory action in OA conditions and increased cartilage regeneration by recruiting intrinsic MSCs, inhibiting progression of OA.

CONCLUSIONS

These therapeutic effects have been validated in diverse OA models, including rabbits, Dunkin Hartley guinea pigs, and human synoviocytes. Therefore, we propose that SAP-SP may be an effective injectable therapeutic agent for treating OA. In this manuscript, we report a preclinical study of novel self-assembled peptide (SAP)-substance P (SP) hydrogels with diverse animal models and human synoviocytes and it displays anti-inflammatory effects, apoptosis inhibition, intrinsic mesenchymal stem cells recruitments and cartilage regeneration.

Nanofat lysate ameliorates pain and cartilage degradation of osteoarthritis through activation of TGF-β–Smad2/3 signaling of chondrocytes

Introduction: Nanofat is an effective cell therapy for osteoarthritis (OA). However, it has clinical limitations due to its short half-life. We developed Nanofat lysate (NFL) to overcome the defect of Nanofat and explore its anti-OA efficacy and mechanism.

Methods: Monoiodoacetate (MIA) was employed to establish rat OA model. For pain assessment, paw withdrawal latency (PWL) and thermal withdrawal latency (TWL) were evaluated. Degeneration of cartilage was observed by histopathological and immunohistochemical examination. Primary chondrocytes were treated with TNF-α to establish the cellular model of OA. MTT, wound healing, and transwell assays were performed to assess effects of NFL on chondrocytes. RNA-seq, qPCR and Western blot assays were conducted to clarify the mechanism of NFL.

Results and Discussion: The animal data showed that PWL and TWL values, Mankin’s and OARSI scorings, and the Col2 expression in cartilage were significantly improved in the NFL-treated OA rats. The cellular data showed that NFL significantly improved the proliferation, wound healing, and migration of chondrocytes. The molecular data showed that NFL significantly restored the TNF-α-altered anabolic markers (Sox9, Col2 and ACAN) and catabolic markers (IL6 and Mmp13). The RNA-seq identified that TGF-β-Smad2/3 signaling pathway mediated the efficacy of NFL, which was verified by qPCR and Western blot that NFL significantly restored the abnormal expressions of TGFβR2, phosphorylated-Smad2, phosphorylated-Smad2/3, Col2, Mmp13 and Mmp3. After long-term storage, NFL exerted similar effects as its fresh type, indicating its advantage of storability. In sum, NFL was developed as a new therapeutic approach and its anti-OA efficacy and mechanism that mediated by TGF-β-Smad2/3 signaling was determined for the first time. Besides, the storability of NFL provided a substantial advantage than other living cell-based therapies.

TGF-β is elevated in hyperuricemic individuals and mediates urate-induced hyperinflammatory phenotype in human mononuclear cells

BACKGROUND

Soluble urate leads to a pro-inflammatory phenotype in human monocytes characterized by increased production of IL-1β and downregulation of IL-1 receptor antagonist, the mechanism of which remains to be fully elucidated. Previous transcriptomic data identified differential expression of genes in the transforming growth factor (TGF)-β pathway in monocytes exposed to urate in vitro. In this study, we explore the role of TGF-β in urate-induced hyperinflammation in peripheral blood mononuclear cells (PBMCs).

METHODS

TGF-β mRNA in unstimulated PBMCs and protein levels in plasma were measured in individuals with normouricemia, hyperuricemia and gout. For in vitro validation, PBMCs of healthy volunteers were isolated and treated with a dose ranging concentration of urate for assessment of mRNA and pSMAD2. Urate and TGF-β priming experiments were performed with three inhibitors of TGF-β signalling: SB-505124, 5Z-7-oxozeaenol and a blocking antibody against TGF-β receptor II.

RESULTS

TGF-β mRNA levels were elevated in gout patients compared to healthy controls. TGF-β-LAP levels in serum were significantly higher in individuals with hyperuricemia compared to controls. In both cases, TGF-β correlated positively to serum urate levels. In vitro, urate exposure of PBMCs did not directly induce TGF-β but did enhance SMAD2 phosphorylation. The urate-induced pro-inflammatory phenotype of monocytes was partly reversed by blocking TGF-β.

CONCLUSIONS

TGF-β is elevated in individuals with hyperuricemia and correlated to serum urate concentrations. In addition, the urate-induced pro-inflammatory phenotype in human monocytes is mediated by TGF-β signalling. Future studies are warranted to explore the intracellular pathways involved and to assess the clinical significance of urate-TGF-β relation.

Elucidating the Focal Immunomodulatory Clues Influencing Mesenchymal Stem Cells in the Milieu of Intervertebral Disc Degeneration

The intervertebral discs (IVDs) are a relatively mobile joint that interconnects vertebrae of the spine. Intervertebral disc degeneration (IVDD) is one of the leading causes of low back pain, which is most often related to patient morbidity as well as high medical costs. Patients with chronic IVDD often need surgery that may sometimes lead to biomechanical complications as well as augmented degeneration of the adjacent segments. Moreover, treatment modalities like rigid intervertebral fusion, dynamic instrumentation, as well as other surgical interventions are still controversial. Mesenchymal stem cells (MSCs) have exhibited to have immunomodulatory functions and the ability to differentiate into cartilage, making these cells possibly an epitome for IVD regeneration. Transplanted MSCs were able to repair IVDD back to the normal disc milieu via the activation of the generation of extracellular matrix (ECM) proteins such as aggrecan, proteoglycans and collagen types I and II. IVD milieu clues like, periostin, cluster of differentiation, tumor necrosis factor alpha, interleukins, chemokines, transforming growth factor beta, reactive oxygen species, toll-like receptors, tyrosine protein kinase receptor and disialoganglioside, exosomes are capable of influencing the MSCs during treatment of IVDD. ECM microenvironment clues above have potentials as biomarkers as well as accurate molecular targets for therapeutic intervention in IVDD.

Maternal immune activation leads to defective brain-blood vessels and intracerebral hemorrhages in male offspring

Intracerebral hemorrhages are recognized risk factors for neurodevelopmental disorders and represent early biomarkers for cognitive dysfunction and mental disability, but the pathways leading to their occurrence are not well defined. We report that a single intrauterine exposure of the immunostimulant Poly I:C to pregnant mice at gestational day 9, which models a prenatal viral infection and the consequent maternal immune activation, induces the defective formation of brain vessels and causes intracerebral hemorrhagic events, specifically in male offspring. We demonstrate that maternal immune activation promotes the production of the TGF-β1 active form and the consequent enhancement of pSMAD1-5 in males' brain endothelial cells. TGF-β1, in combination with IL-1β, reduces the endothelial expression of CD146 and claudin-5, alters the endothelium-pericyte interplay resulting in low pericyte coverage, and increases hemorrhagic events in the adult offspring. By showing that exposure to Poly I:C at the beginning of fetal cerebral angiogenesis results in sex-specific alterations of brain vessels, we provide a mechanistic framework for the association between intragravidic infections and anomalies of the neural vasculature, which may contribute to neuropsychiatric disorders.

IL-1α and TNF-α as an inducer for ROS-mediated NLRP1/NLRP3 inflammasomes activation in mononuclear blood cells from individuals with chronic insomnia disorder

BACKGROUND

There are some evidence that cytokines may play an important role in sleep deprivation; however, the underlying mechanisms are still unknown. So, the present study aim to evaluate the relationship between NLRP1 and NLRP3 inflammasomes activation of blood cells and serum levels of cytokines in individuals with chronic insomnia disorder (CID).

METHODS

Blood samples were collected from 24 individuals with CID and 24 healthy volunteers. The inflammasomes activation was evaluated using real time PCR of NLRP1, NLRP3, ASC, and Caspase-1; western blot of NLRP1 and NLRP3; caspase-1 activity assay; and serum levels of IL-1β, IL-18 and other cytokines using enzyme-linked immunosorbent assay (ELISA). ROS generation in blood cells were detected by flow cytometry assay. As well, MRI scans were obtained on a Siemens Magnetom Avanto 1.5 T MRI whole body scanner using an 8-channel head coil.

RESULTS

We found the increased activity of NLRP1 and NLRP3 inflammasomes in blood cells; the increased serum levels of pro-inflammatory cytokines; and the decreased serum levels of IL-10 and TGF-β in individuals with CID. We observed significant correlation between increased serum concentration of IL-1β and the severity of insomnia in individuals with CID. The levels of ROS in blood cells was found to be correlated with IL-1α and TNF-α concentrations in serums from individuals with CID. Moreover, the included individuals with CID demonstrated the increased right-cerebellum-cortex and lateral ventricle MD bilaterally compared to controls.

CONCLUSIONS

This study provided new insights on the pathogenesis of CID and the effects of cytokines on inflammasome activation.

DNA methylation and noncoding RNA in OA: Recent findings and methodological advances

Introduction:

Osteoarthritis (OA) is a chronic musculoskeletal disease characterized by progressive loss of joint function. Historically, it has been characterized as a disease caused by mechanical trauma, so-called ‘wear and tear’. Over the past two decades, it has come to be understood as a complex systemic disorder involving gene-environmental interactions. Epigenetic changes have been increasingly implicated. Recent improvements in microarray and next-generation sequencing (NGS) technologies have allowed for ever more complex evaluations of epigenetic aberrations associated with the development and progression of OA.

Methods:

A systematic review was conducted in the Pubmed database. We curated studies that presented the results of DNA methylation and noncoding RNA research in human OA and OA animal models since 1985.

Results:

Herein, we discuss recent findings and methodological advancements in OA epigenetics, including a discussion of DNA methylation, including microarray and NGS studies, and noncoding RNAs. Beyond cartilage, we also highlight studies in subchondral bone and peripheral blood mononuclear cells, which highlight widespread and potentially clinically important alterations in epigenetic patterns seen in OA patients. Finally, we discuss epigenetic editing approaches in the context of OA.

Conclusions:

Although a substantial body of literature has already been published in OA, much is still unknown. Future OA epigenetics studies will no doubt continue to broaden our understanding of underlying pathophysiology and perhaps offer novel diagnostics and/or treatments for human OA.

Regulatory network-based model to simulate the biochemical regulation of chondrocytes in healthy and osteoarthritic environments

In osteoarthritis (OA), chondrocyte metabolism dysregulation increases relative catabolic activity, which leads to cartilage degradation. To enable the semiquantitative interpretation of the intricate mechanisms of OA progression, we propose a network-based model at the chondrocyte level that incorporates the complex ways in which inflammatory factors affect structural protein and protease expression and nociceptive signals. Understanding such interactions will leverage the identification of new potential therapeutic targets that could improve current pharmacological treatments. Our computational model arises from a combination of knowledge-based and data-driven approaches that includes in-depth analyses of evidence reported in the specialized literature and targeted network enrichment. We achieved a mechanistic network of molecular interactions that represent both biosynthetic, inflammatory and degradative chondrocyte activity. The network is calibrated against experimental data through a genetic algorithm, and 81% of the responses tested have a normalized root squared error lower than 0.15. The model captures chondrocyte-reported behaviors with 95% accuracy, and it correctly predicts the main outcomes of OA treatment based on blood-derived biologics. The proposed methodology allows us to model an optimal regulatory network that controls chondrocyte metabolism based on measurable soluble molecules. Further research should target the incorporation of mechanical signals.

Role of microRNA Shuttled in Small Extracellular Vesicles Derived From Mesenchymal Stem/Stromal Cells for Osteoarticular Disease Treatment

Osteoarticular diseases (OD), such as rheumatoid arthritis (RA) and osteoarthritis (OA) are chronic autoimmune/inflammatory and age-related diseases that affect the joints and other organs for which the current therapies are not effective. Cell therapy using mesenchymal stem/stromal cells (MSCs) is an alternative treatment due to their immunomodulatory and tissue differentiation capacity. Several experimental studies in numerous diseases have demonstrated the MSCs’ therapeutic effects. However, MSCs have shown heterogeneity, instability of stemness and differentiation capacities, limited homing ability, and various adverse responses such as abnormal differentiation and tumor formation. Recently, acellular therapy based on MSC secreted factors has raised the attention of several studies. It has been shown that molecules embedded in extracellular vesicles (EVs) derived from MSCs, particularly those from the small fraction enriched in exosomes (sEVs), effectively mimic their impact in target cells. The biological effects of sEVs critically depend on their cargo, where sEVs-embedded microRNAs (miRNAs) are particularly relevant due to their crucial role in gene expression regulation. Therefore, in this review, we will focus on the effect of sEVs derived from MSCs and their miRNA cargo on target cells associated with the pathology of RA and OA and their potential therapeutic impact.

Evaluation of the influence of platelet-rich plasma (PRP), platelet lysate (PL) and mechanical loading on chondrogenesis in vitro

The aim of this work is to investigate the capability of PRP as an adjuvant therapy to autologous chondrocyte implantation (ACI) in combination with multi-axial load with respect to cartilage regeneration. Articular cartilage shows poor repair capacity and therapies for cartilage defects are still lacking. Well-established operative treatments include ACI, and growing evidence shows the beneficial effects of PRP. Platelets contain numerous growth factors, among them transforming growth factor beta (TGF-β). Dynamic mechanical loading is known to be essential for tissue formation, improving extracellular matrix (ECM) production. For our ACI model monolayer expanded human chondrocytes were seeded into polyurethane scaffolds and embedded in fibrin (hChondro), in PRP-Gel (PRP), or in fibrin with platelet lysate (PL), which was added to the media once a week with a concentration of 50 vol%. The groups were either exposed to static conditions or multi-axial forces in a ball-joint bioreactor for 1 h per day over 2 weeks, mimicking ACI under physiological load. The culture medium was collected and analyzed for glycosaminoglycan (GAG), nitrite and transforming growth factor beta 1 (TGF-β1) content. The cell-scaffold constructs were collected for DNA and GAG quantification; the expression of chondrogenic genes, TGF-β and related receptors, as well as inflammatory genes, were analyzed using qPCR. Loading conditions showed superior chondrogenic differentiation (upregulation of COL2A1, ACAN, COMP and PRG4 expression) than static conditions. PRP and PL groups combined with mechanical loading showed upregulation of COL2A1, ACAN and COMP. The highest amount of total TGF-β1 was quantified in the PL group. Latent TGF-β1 was activated in all loaded groups, while the highest amount was found in the PL group. Load increased TGFBR1/TGFBR2 mRNA ratio, with further increases in response to supplements. In general, loading increased nitrite release into the media. However, over time, the media nitrite content was lower in the PL group compared to the control group. Based on these experiments, we conclude that chondrogenic differentiation is strongest when simulated ACI is performed in combination with dynamic mechanical loading and PRP-gel or PL supplementation. An inflammatory reaction was reduced by PRP and PL, which could be one of the major therapeutic effects. Loading presumably can enhance the action of TGF-β1, which was predominantly activated in loaded PL groups. The combination of load and PRP represents an effective and promising synergy concerning chondrocyte-based cartilage repair.

Biomaterial-based delivery of nucleic acids for tissue regeneration

Gene therapy is a promising novel method of tissue regeneration by stimulating or inhibiting key signaling pathways. However, their therapeutic applications in vivo are largely limited by several physiological obstacles, such as degradation of nucleases, impermeability of cell membranes, and transport to the desired intracellular compartments. Biomaterial-based gene delivery systems can overcome the problems of stability and local drug delivery, and can temporarily control the overexpression of therapeutic genes, leading to the local production of physiologically relevant levels of regulatory factors. But the gene delivery of biomaterials for tissue regeneration relies on multi-factor design. This review aims to outline the impact of gene delivery methods, therapeutic genes and biomaterials selection on this strategy, emphatically introduce the latest developments in the design of gene delivery vehicles based on biomaterials, summarize the mechanism of nucleic acid for tissue regeneration, and explore the strategies of nucleic acid delivery vehicles for various tissue regeneration.

Osteoarthritis-Related Inflammation Blocks TGF-β's Protective Effect on Chondrocyte Hypertrophy via (de)Phosphorylation of the SMAD2/3 Linker Region

Osteoarthritis (OA) is a degenerative joint disease characterized by irreversible cartilage damage, inflammation and altered chondrocyte phenotype. Transforming growth factor-β (TGF-β) signaling via SMAD2/3 is crucial for blocking hypertrophy. The post-translational modifications of these SMAD proteins in the linker domain regulate their function and these can be triggered by inflammation through the activation of kinases or phosphatases. Therefore, we investigated if OA-related inflammation affects TGF-β signaling via SMAD2/3 linker-modifications in chondrocytes. We found that both Interleukin (IL)-1β and OA-synovium conditioned medium negated SMAD2/3 transcriptional activity in chondrocytes. This inhibition of TGF-β signaling was enhanced if SMAD3 could not be phosphorylated on Ser213 in the linker region and the inhibition by IL-1β was less if the SMAD3 linker could not be phosphorylated at Ser204. Our study shows evidence that inflammation inhibits SMAD2/3 signaling in chondrocytes via SMAD linker (de)-phosphorylation. The involvement of linker region modifications may represent a new therapeutic target for OA.

Proteomic Analysis Reveals Commonly Secreted Proteins of Mesenchymal Stem Cells Derived from Bone Marrow, Adipose Tissue, and Synovial Membrane to Show Potential for Cartilage Regeneration in Knee Osteoarthritis

Paracrine factors secreted by mesenchymal stem cells (MSCs) reportedly modulate inflammation and reparative processes in damaged tissues and have been explored for knee osteoarthritis (OA) therapy. Although various studies have reported the effects of paracrine factors in knee OA, it is not yet clear which paracrine factors directly affect the regeneration of damaged cartilage and which are secreted under various knee OA conditions. In this study, we cultured MSCs derived from three types of tissues and treated each type with IL-1β and TNF-α or not to obtain conditioned medium. Each conditioned medium was used to analyse the paracrine factors related to cartilage regeneration using liquid chromatography-tandem mass spectrometry. Bone marrow-, adipose tissue-, and synovial membrane-MSCs (all-MSCs) exhibited expression of 93 proteins under normal conditions and 105 proteins under inflammatory conditions. It was confirmed that the types of secreted proteins differed depending on the environmental conditions, and the proteins were validated using ELISA. The results of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis using a list of proteins secreted by all-MSCs under each condition confirmed that the secreted proteins were closely related to cartilage repair under inflammatory conditions. Protein-protein interaction networks were confirmed to change depending on environmental differences and were found to enhance the secretion of paracrine factors related to cartilage regeneration under inflammatory conditions. In conclusion, our results demonstrated that compared with knee OA conditions, the differential expression proteins may contribute to the regeneration of damaged cartilage. In addition, the detailed information on commonly secreted proteins by all-MSCs provides a comprehensive basis for understanding the potential of paracrine factors to influence tissue repair and regeneration in knee OA.

Clusterin secretion is attenuated by the proinflammatory cytokines interleukin-1β and tumor necrosis factor-α in models of cartilage degradation

The protein clusterin has been implicated in the molecular alterations that occur in articular cartilage during osteoarthritis (OA). Clusterin exists in two isoforms with opposing functions, and their roles in cartilage have not been explored. The secreted form of clusterin (sCLU) is a cytoprotective extracellular chaperone that prevents protein aggregation, enhances cell proliferation and promotes viability, whereas nuclear clusterin acts as a pro-death signal. Therefore, these two clusterin isoforms may be putative molecular markers of repair and catabolic responses in cartilage and the ratio between them may be important. In this study, we focused on sCLU and used established, pathophysiologically relevant, in vitro models to understand its role in cytokine-stimulated cartilage degradation. The secretome of equine cartilage explants, osteochondral biopsies and isolated unpassaged chondrocytes was analyzed by western blotting for released sCLU, cartilage oligomeric protein (COMP) and matrix metalloproteinases (MMP) 3 and 13, following treatment with the proinflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α. Release of sulfated glycosaminoglycans (sGAG) was determined using the dimethylmethylene blue assay. Clusterin messenger RNA (mRNA) expression was quantified by quantitative real-time polymerase chain reaction. MMP-3, MMP-13, COMP, and sGAG release from explants and osteochondral biopsies was elevated with cytokine treatment, confirming cartilage degradation in these models. sCLU release was attenuated with cytokine treatment in all models, potentially limiting its cytoprotective function. Clusterin mRNA expression was down-regulated 7-days post cytokine stimulation. These observations implicate sCLU in catabolic responses of chondrocytes, but further studies are required to evaluate its role in OA and its potential as an investigative biomarker.

Transforming growth factor-β1 inhibits interleukin-1β-induced expression of inflammatory genes and Cathepsin S activity in human vascular smooth muscle cells

OBJECTIVE AND DESIGN

This study investigated the opposite mechanisms by which IL-1β and TGF-β1 modulated the inflammatory and migratory phenotypes in cultured human intimal vascular smooth muscle cells vSMCs.

MATERIALS AND TREATMENT

Primary human vSMCs, obtained from twelve hypertensive patients who underwent carotid endarterectomy, were incubated for 24 hours with either 40 pM TGF-β1, or 1 nmol/L IL-1β, or their combination in presence or absence of anti-TGF-β neutralizing antibody.

METHODS

The expression levels of matrix metalloproteases and their inhibitors, and the elastolytic enzyme cathepsin S (CTSS) and its inhibitor cystatin C were evaluated with RT-PCR. CTSS activity was measured by fluorometry.

RESULTS

TGF-β1 reversed IL-1β-induced expression of iNOS, CXCL6, IL1R1, MMP12, and CTSS, while upregulated TIMP2 expression. Furthermore, anti-TGF-β neutralizing antibody abrogated TGF-β effects. Combination with IL-1β and TGF-β1 induced the expression of IL1α, IL1β, IL1R1, and CTSS, but suppressed CST3 expression. CTSS expression in the combination treatment was higher than that of cells treated with anti-TGF-β antibodies alone. Moreover, IL-1β-induced CTSS enzymatic activity was reduced when human vSMCs were co-treated with TGF-β, whereas this reduction was abrogated by anti-TGF-β neutralizing antibody.

CONCLUSION

TGF-β1 abrogated IL-1β-induced expression of inflammatory genes and elastolytic activity in cultured human vSMCs. Thus, TGF-β1 can play a crucial role in impairing IL-1β-induced vascular inflammation and damage involved in the etiology of cardiovascular diseases.

MK801 regulates the expression of key osteoarthritis factors in osteoarthritis synovial fibroblasts through complement C5

BACKGROUND

Osteoarthritis is currently one of the most common chronic diseases. As life expectancy increases, its prevalence and incidence are expected to rise. At present, more and more evidences prove the correlation between the complement system and osteoarthritis (OA). This study aims to investigate complement C5's influence on the effect of MK801 on osteoarthritis synovial fibroblasts (OA-SFs).

METHODS

We used IL-1b to induce OA-SFs derived from mice to obtain OA-SFs. And we performed RT-PCR and Western Blot assays to evaluate the expression levels of associated mRNA and protein. The alteration of MAC expression on OA-SFs cell membrane was evaluated by immunofluorescence assay. The expression of related inflammatory factors of OA-SFs was evaluated by ELISA experiment.

RESULTS

MK801 could significantly inhibit the expression of osteoarthritis (OA) marker factors, such as: membrane attack complex (MAC), tumor necrosis factor-α (TNF-α) and matrix metalloproteinase-13 (MMP13). Meanwhile, MK801 can significantly inhibit the expression of complement C5 (C5) in OA-SFs. Immunofluorescence assay showed that MAC expression on OA-SFs cell membrane was significantly inhibited by MK801. The nucleo-plasmic separation experiment demonstrated that MK801 could significantly inhibit the activation of Nuclear factor-κB (NF-κB) signaling pathway in OA-SFs. Futhermore, koncking down the expression of C5 reversed the inhibition MK801 on the expression of OA-SFs inflammatory factors.

CONCLUSIONS

These results illustrated two points: first, MK801 inhibited the generation of MAC and the release of inflammation factors in OA-SFs through C5; second: MK801 inhibited the activation of NF-κB signaling pathway in OA-SFs.

An Evidence-Based Systematic Review of Human Knee Post-Traumatic Osteoarthritis (PTOA): Timeline of Clinical Presentation and Disease Markers, Comparison of Knee Joint PTOA Models and Early Disease Implications

Understanding the causality of the post-traumatic osteoarthritis (PTOA) disease process of the knee joint is important for diagnosing early disease and developing new and effective preventions or treatments. The aim of this review was to provide detailed clinical data on inflammatory and other biomarkers obtained from patients after acute knee trauma in order to (i) present a timeline of events that occur in the acute, subacute, and chronic post-traumatic phases and in PTOA, and (ii) to identify key factors present in the synovial fluid, serum/plasma and urine, leading to PTOA of the knee in 23-50% of individuals who had acute knee trauma. In this context, we additionally discuss methods of simulating knee trauma and inflammation in in vivo, ex vivo articular cartilage explant and in vitro chondrocyte models, and answer whether these models are representative of the clinical inflammatory stages following knee trauma. Moreover, we compare the pro-inflammatory cytokine concentrations used in such models and demonstrate that, compared to concentrations in the synovial fluid after knee trauma, they are exceedingly high. We then used the Bradford Hill Framework to present evidence that TNF-α and IL-6 cytokines are causal factors, while IL-1β and IL-17 are credible factors in inducing knee PTOA disease progresssion. Lastly, we discuss beneficial infrastructure for future studies to dissect the role of local vs. systemic inflammation in PTOA progression with an emphasis on early disease.

Synergistic interaction of hTGF-β3 with hBMP-6 promotes articular cartilage formation in chitosan scaffolds with hADSCs: implications for regenerative medicine

Background

Human TGF-β₃ has been used in many studies to induce genes coding for typical cartilage matrix components and accelerate chondrogenic differentiation, making it the standard constituent in most cultivation media used for the assessment of chondrogenesis associated with various stem cell types on carrier matrices. However, in vivo data suggests that TGF-β₃ and its other isoforms also induce endochondral and intramembranous osteogenesis in non-primate species to other mammals. Based on previously demonstrated improved articular cartilage induction by a using hTGF-β₃ and hBMP-6 together on hADSC cultures and the interaction of TGF- β with matrix in vivo, the present study investigates the interaction of a chitosan scaffold as polyanionic polysaccharide with both growth factors. The study analyzes the difference between chondrogenic differentiation that leads to stable hyaline cartilage and the endochondral ossification route that ends in hypertrophy by extending the usual panel of investigated gene expression and stringent employment of quantitative PCR.

Results

By assessing the viability, proliferation, matrix formation and gene expression patterns it is shown that hTGF-β₃ + hBMP-6 promotes improved hyaline articular cartilage formation in a chitosan scaffold in which ACAN with Col2A1 and not Col1A1 nor Col10A1 where highly expressed both at a transcriptional and translational level. Inversely, hTGF-β₃ alone tended towards endochondral bone formation showing according protein and gene expression patterns.

Conclusion

These findings demonstrate that clinical therapies should consider using hTGF-β₃ + hBMP-6 in articular cartilage regeneration therapies as the synergistic interaction of these morphogens seems to ensure and maintain proper hyaline articular cartilage matrix formation counteracting degeneration to fibrous tissue or ossification. These effects are produced by interaction of the growth factors with the polysaccharide matrix.

Induction of Articular Chondrogenesis by Chitosan/Hyaluronic-Acid-Based Biomimetic Matrices Using Human Adipose-Derived Stem Cells

Cartilage repair using tissue engineering is the most advanced clinical application in regenerative medicine, yet available solutions remain unsuccessful in reconstructing native cartilage in its proprietary form and function. Previous investigations have suggested that the combination of specific bioactive elements combined with a natural polymer could generate carrier matrices that enhance activities of seeded stem cells and possibly induce the desired matrix formation. The present study sought to clarify this by assessing whether a chitosan-hyaluronic-acid-based biomimetic matrix in conjunction with adipose-derived stem cells could support articular hyaline cartilage formation in relation to a standard chitosan-based construct. By assessing cellular development, matrix formation, and key gene/protein expressions during in vitro cultivation utilizing quantitative gene and immunofluorescent assays, results showed that chitosan with hyaluronic acid provides a suitable environment that supports stem cell differentiation towards cartilage matrix producing chondrocytes. However, on the molecular gene expression level, it has become apparent that, without combinations of morphogens, in the chondrogenic medium, hyaluronic acid with chitosan has a very limited capacity to stimulate and maintain stem cells in an articular chondrogenic state, suggesting that cocktails of various growth factors are one of the key features to regenerate articular cartilage, clinically.

TGFβ/BMP Signaling Pathway in Cartilage Homeostasis

Cartilage homeostasis is governed by articular chondrocytes via their ability to modulate extracellular matrix production and degradation. In turn, chondrocyte activity is regulated by growth factors such as those of the transforming growth factor β (TGFβ) family. Members of this family include the TGFβs, bone morphogenetic proteins (BMPs), and growth and differentiation factors (GDFs). Signaling by this protein family uniquely activates SMAD-dependent signaling and transcription but also activates SMAD-independent signaling via MAPKs such as ERK and TAK1. This review will address the pivotal role of the TGFβ family in cartilage biology by listing several TGFβ family members and describing their signaling and importance for cartilage maintenance. In addition, it is discussed how (pathological) processes such as aging, mechanical stress, and inflammation contribute to altered TGFβ family signaling, leading to disturbed cartilage metabolism and disease.

Centrifugation Conditions in the L-PRP Preparation Affect Soluble Factors Release and Mesenchymal Stem Cell Proliferation in Fibrin Nanofibers

Leukocyte and platelet-rich plasma (L-PRP) is an autologous product that when activated forms fibrin nanofibers, which are useful in regenerative medicine. As an important part of the preparation of L-PRP, the centrifugation parameters may affect the release of soluble factors that modulate the behavior of the cells in the nanofibers. In this study, we evaluated the influences of four different centrifugation conditions on the concentration of platelets and leukocytes in L-PRP and on the anabolic/catabolic balance of the nanofiber microenvironment. Human adipose-derived mesenchymal stem cells (h-AdMSCs) were seeded in the nanofibers, and their viability and growth were evaluated. L-PRPs prepared at 100× g and 100 + 400× g released higher levels of transforming growth factor (TGF)-β1 and platelet-derived growth factor (PDGF)-BB due to the increased platelet concentration, while inflammatory cytokines interleukin (IL)-8 and tumor necrosis factor (TNF)-α were more significantly released from L-PRPs prepared via two centrifugation steps (100 + 400× g and 800 + 400× g) due to the increased concentration of leukocytes. Our results showed that with the exception of nanofibers formed from L-PRP prepared at 800 + 400× g, all other microenvironments were favorable for h-AdMSC proliferation. Here, we present a reproducible protocol for the standardization of L-PRP and fibrin nanofibers useful in clinical practices with known platelet/leukocyte ratios and in vitro evaluations that may predict in vivo results.

Salidroside attenuates interleukin-1β-induced inflammation in human osteoarthritis chondrocytes

Salidroside, a bioactive constituent isolated from Rhodiola rosea, has been reported to have anti-inflammatory effects. However, the effects of salidroside on interleukin (IL)-1β-stimulated osteoarthritis (OA) chondrocytes remain to be elucidated. Thus, this study aimed to evaluate the anti-inflammatory effects of salidroside on IL-1β-stimulated human OA chondrocytes and explore its underlying mechanisms. Our results showed that salidroside significantly inhibited the production of nitric oxide and prostaglandin E-2, as well as suppressed the expression of inducible nitric oxide synthase and cyclooxygenase-2 in IL-1β-stimulated chondrocytes ( P < .05). In addition, salidroside also suppressed IL-1β-induced matrix metalloproteinases production in human OA chondrocytes ( P < .05). Furthermore, pretreatment with salidroside prevented IL-1β-induced NF-κB activation in OA chondrocytes ( P < .05). In conclusion, the current study demonstrated that salidroside inhibited the IL-1β-induced inflammatory response in OA chondrocytes via inhibition of NF-κB activation.

Role of Prefrontal Cortex Anti- and Pro-inflammatory Cytokines in the Development of Abnormal Behaviors Induced by Disconnection of the Ventral Hippocampus in Neonate Rats

Neonatal disconnection of ventral hippocampus (VH) outputs in rats has been reported to lead to post-pubertal behavioral and synaptic changes of relevance to schizophrenia. Increased oxidative and inflammatory load in the prefrontal cortex (PFC) has been suggested to mediate some of the effects of neonatal VH lesion (NVHL). In this study, we hypothesized that developmental imbalance of anti- and pro-inflammatory factors within the PFC might affect synaptic development thus contributing to the adult NVHL-induced behavioral deficits. Ibotenic acid-induced excitotoxic NVHL was performed in postnatal day (PD) 7 male Sprague-Dawley rats and the mRNA levels of select pro- and anti-inflammatory cytokines were measured in the medial PFC (mPFC) at two developmental time points (PD15 and PD60). We observed a development-specific increase of pro-inflammatory cytokine, interleukin (IL)-1β mRNA at PD15, and an overall reduction in the expression and signaling of transforming growth factor beta 1 (TGF-β1), an anti-inflammatory cytokine, at both PD15 and PD60 in the NVHL animals. These cytokine changes were not seen in the somatosensory cortex (SSC) or tissue surrounding the lesion site. Daily administration of systemic recombinant TGF-β1 from PD7-14 prevented the appearance of hyperlocomotion, deficits in prepulse inhibition (PPI) of startle and social interaction (SI) in post-pubertal (PD60) NVHL rats. Neonatal supplementation of TGF-β1 was also able to attenuate dendritic spine loss in the layer 3 mPFC pyramidal neurons of NVHL animals. These results suggest that early damage of the VH has long-lasting inflammatory consequences in distant connected structures, and that TGF-β1 has potential to confer protection against the deleterious effects of developmental hippocampal damage.

Autophagy Is Independent of the Chondroprotection Induced by Platelet-Rich Plasma Releasate

Background

Platelet-rich plasma (PRP) has been shown to be a promising therapeutic agent against osteoarthritis (OA), whereas its chondroprotection mechanism is not fully elucidated. Autophagy is considered an important biological process throughout the development of OA. Therefore, the objective of the present study is to investigate the role of autophagy in the chondroprotection and compare the effects of releasate between L-PRP and P-PRP.

Methods

PRP were prepared from rat blood. Rat chondrocytes pretreated in the presence or absence of interleukin-1 beta (IL-1β) were incubated with PRP releasate. The expressions of OA-related genes and autophagy-related genes were determined by RT-PCR and western blot, respectively. Autophagic bodies were assessed by transmission electron microscopy and the autophagy flux was monitored under the confocal microscopy. The effect of PRP on autophagy was further investigated in the milieu of autophagy activator, rapamycin, or autophagy inhibition by downregulation of Atg5. The effect of PRP on cartilage repair and autophagy was also evaluated in an OA rat model.

Results

In vitro, PRP releasate increased the expression of the anabolic genes, COL2 and Aggrecan, and decreased the expression of the catabolic genes, whereas the expression of autophage markers, Atg5 and Beclin-1, as well as the ratio of LC3 II/LC3 I, was not significantly altered in normal or IL-1β-treated chondrocytes. Similar expression pattern was found following the activation (rapamycin) or inhibition (Atg5 silencing) of autophagy. In vivo, PRP releasate ameliorated posttraumatic cartilage degeneration while the expression of LC3 was comparable to that in the vehicle treatment group.

Conclusions

PRP releasate promoted the anabolic gene expression, relieved inflammatory stress in chondrocytes, and ameliorated cartilage degeneration, but autophagy was independent of these processes.

Use of mesenchymal stem cells seeded on the scaffold in articular cartilage repair

Articular cartilage has poor capacity for repair. Once damaged, they degenerate, causing functional impairment of joints. Allogeneic cartilage transplantation has been performed for functional recovery of articular cartilage. However, there is only a limited amount of articular cartilage available for transplantation. Mesenchymal stem cells (MSCs) could be potentially suitable for local implantation. MSCs can differentiate into chondrocytes. Several studies have demonstrated the therapeutic potential of MSCs in the repair of articular cartilage in animal models of articular cartilage damage and in patients with damaged articular cartilage. To boost post-implantation MSC differentiation into chondrocytes, the alternative delivery methods by scaffolds, using hyaluronic acid (HA) or poly-lactic-co-glycolic-acid (PLGA), have developed. In this review, we report recent data on the repair of articular cartilage and discuss future developments.

Quality assessment of cellular and tissue-based products using liquid chromatography-tandem mass spectrometry

We are currently conducting clinical research on cell sheets for cartilage regeneration. One issue with the future use of chondrocyte sheets as cellular and tissue-based products is quality assessment. Currently, chondrocyte sheets are evaluated using invasive methods that cannot be performed on every sheet produced. We report here on our liquid chromatography-tandem mass spectrometry (LC-MS/MS) technique that allows the noninvasive assessment of every sheet using only 50 μl of culture medium. We found that LC-MS/MS could be used to confirm cell sheet viability through the measurement of glucose and glutamine uptake, to estimate extracellular matrix production by measuring serine consumption, to estimate cell kinetics by measuring cytidine and uracil concentrations, and to estimate melanoma inhibitory activity level by measuring pyridoxal concentration. LC-MS/MS may be useful for the noninvasive assessment of products to be used in regenerative medicine.

Down-regulation of microRNA-216b inhibits IL-1β-induced chondrocyte injury by up-regulation of Smad3

Osteoarthritis (OA) is the most common type of joint disease, leading to a major cause of pain and disability. OA is characterized by the continuous degradation of articular cartilage, mainly resulting in an imbalance between synthesis and degradation of articular chondrocyte extracellular matrix (ECM). Aberrant miR-216b expression has been found in multiple cancers. However, the level of miR-216b in OA cartilage and its role in progression of this disease are still unknown. In the present study, the functional roles of miR-216b and its expression in OA tissues and interleukin-1β (IL-1β)-induced chondrocytes were examined. We found that the level of miR-216b was significantly higher and Smad3 expression was obviously lower in OA cartilage and IL-1β-induced chondrocytes than in normal tissues and cells. Furthermore, a bioinformatics analysis and luciferase reporter assay identified Smad3 as a direct target gene of miR-216b, and Smad3 expression was reduced by miR-216b overexpression at both the mRNA and protein levels. A functional analysis demonstrated that miR-216b down-regulation obviously alleviated the IL-1β-induced inhibition in cell proliferation, type II collagen, and aggrecan down-regulation and matrix metalloproteinase-13 (MMP-13) up-regulation, while miR-216b overexpression had the opposite effects. Knockdown of Smad3 by siRNA reversed the effects of the miR-216b inhibitor on cell proliferation, the expressions of type II collagen, aggrecan, and MMP-13. Our results suggested that miR-216b contributes to progression of OA by directly targeting Smad3, providing a potential therapeutic target for treatment of OA.

Crosstalk between Smad2/3 and specific isoforms of ERK in TGF-β1-induced TIMP-3 expression in rat chondrocytes

This study investigated the roles of ERK1 and ERK2 in transforming growth factor‐β1 (TGF‐β1)‐induced tissue inhibitor of metalloproteinases‐3 (TIMP‐3) expression in rat chondrocytes, and the specific roles of ERK1 and ERK2 in crosstalk with Smad2/3 were investigated to demonstrate the molecular mechanism of ERK1/2 regulation of TGF‐β1 signalling. To examine the interaction of specific isoforms of ERK and the Smad2/3 signalling pathway, chondrocytes were infected with LV expressing either ERK1 or ERK2 siRNA and stimulated with or without TGF‐β1. At indicated time‐points, TIMP‐3 expression was determined by real‐time PCR and Western blotting; p‐Smad3, nuclear p‐Smad3, Smad2/3, p‐ERK1/2 and ERK1/2 levels were assessed. And then, aggrecan, type II collagen and the intensity of matrix were examined. TGF‐β1‐induced TIMP‐3 expression was significantly inhibited by ERK1 knock‐down, and the decrease in TIMP‐3 expression was accompanied by a reduction of p‐Smad3 in ERK1 knock‐down cells. Knock‐down of ERK2 had no effect on neither TGF‐β1‐induced TIMP‐3 expression nor the quantity of p‐Smad3. Moreover, aggrecan, type II collagen expression and the intensity of matrix were significantly suppressed by ERK1 knock‐down instead of ERK2 knock‐down. Taken together, ERK1 and ERK2 have different roles in TGF‐β1‐induced TIMP‐3 expression in rat chondrocytes. ERK1 instead of ERK2 can regulate TGF‐β/Smad signalling, which may be the mechanism through which ERK1 regulates TGF‐β1‐induced TIMP‐3 expression.

MicroRNA-15b silencing inhibits IL-1β-induced extracellular matrix degradation by targeting SMAD3 in human nucleus pulposus cells

OBJECTIVES

To determine the role of microRNA-15b (miR-15b) in interleukin-1 beta (IL-1β)-induced extracellular matrix (ECM) degradation in the nucleus pulposus (NP).

RESULTS

MiR-15b was up-regulated in degenerative NP tissues and in IL-1β-stimulated NP cells, as compared to the levels in normal controls (normal tissue specimens from patients with idiopathic scoliosis). Bioinformatics and luciferase activity analyses showed that mothers against decapentaplegic homolog 3 (SMAD3), a key mediator of the transforming growth factor-β signaling pathway, was directly targeted by miR-15b. Functional analysis demonstrated that miR-15b overexpression aggravated IL-1β-induced ECM degradation in NP cells, while miR-15b inhibition had the opposite effects. Prevention of IL-1β-induced NP ECM degeneration by the miR-15b inhibitor was attenuated by small-interfering-RNA-mediated knockdown of SMAD3. In addition, activation of MAP kinase and nuclear factor-κB up-regulated miR-15b expression and down-regulated SMAD3 expression in IL-1β-stimulated NP cells.

CONCLUSIONS

MiR-15b contributes to ECM degradation in intervertebral disc degeneration (IDD) via targeting of SMAD3, thus providing a novel therapeutic target for IDD treatment.

Roles of microRNA and signaling pathway in osteoarthritis pathogenesis

Osteoarthritis (OA) is a common chronic degenerative joint disease, with complicated pathogenic factors and undefined pathogenesis. Various signaling pathways play important roles in OA pathogenesis, including genetic expression, matrix synthesis and degradation, cell proliferation, differentiation, apoptosis, and so on. MicroRNA (miRNA) is a class of non-coding RNA in Eukaryon, regulating genetic expression on the post-transcriptional level. A great number of miRNAs are involved in the development of OA, and are closely associated with different signaling pathways. This article reviews the roles of miRNAs and signaling pathways in OA, looking toward having a better understanding of its pathogenesis mechanisms and providing new therapeutic targets for its treatment.

Inflammatory conditions partly impair the mechanically mediated activation of Smad2/3 signaling in articular cartilage

Background

Joint trauma, which is frequently related with mechanical overloading of articular cartilage, is a well-established risk for osteoarthritis (OA) development. Additionally, reports show that trauma leads to synovial joint inflammation. In consequence, after joint trauma, cartilage is influenced by deleterious excessive loading combined with the catabolic activity of proinflammatory mediators. Since the activation of TGF-β signaling by loading is considered to be a key regulatory pathway for maintaining cartilage homeostasis, we tested the effect of proinflammatory conditions on mechanically mediated activation of TGF-β/Smad2/3P signaling in cartilage.

Methods

Cartilage explants were subjected to dynamic mechanical compression in the presence of interleukin-1 beta (IL-1β) or osteoarthritic synovium-conditioned medium (OAS-CM). Subsequently, the activation of the Smad2/3P pathway was monitored with QPCR analysis of reporter genes and additionally the expression of receptors activating the Smad2/3P pathway was analyzed. Finally, the ability for mechanically mediated activation of Smad2/3P was tested in human OA cartilage.

Results

IL-1β presence during compression did not impair the upregulation of Smad2/3P reporter genes, however the results were affected by IL-1β-mediated upregulations in unloaded controls. OAS-CM significantly impaired the compression-mediated upregulation of bSmad7 and Tgbfb1. IL-1β suppressed the compression-mediated bAlk5 upregulation where 12 MPa compression applied in the presence of OAS-CM downregulated the bTgfbr2. Mechanically driven upregulation of Smad2/3P reporter genes was present in OA cartilage.

Conclusions

Proinflammatory conditions partly impair the mechanically mediated activation of the protective TGF-β/Smad2/3P pathway. Additionally, the excessive mechanical compression, applied in the presence of proinflammatory conditions diminishes the expression of the type II TGF-β receptor, a receptor critical for maintenance of articular cartilage.

Identification of genes required for the spontaneous repair of partial-thickness cartilage defects in immature rats

PURPOSE

Our previous study showed that partial-thickness articular cartilage defects (PTCDs) created in immature rats spontaneously healed to resemble normal hyaline cartilage, but that of mature rats did not. To identify molecules involved in the spontaneous cartilage repair observed in this model, gene expression was compared between PTCD and sham-operated cartilage of immature and mature rats.

MATERIALS AND METHODS

Six sets of gene comparisons were made at 12, 24, and 48 hours after the creation of PTCDs in immature and mature rats using microarrays. All the genes upregulated in immature cartilage at 12 hours were selected for further analysis if their expression pattern was not irregular such that diminished at 24 hours and re-upregulated at 48 hours. Relationships among genes selected through the above steps were analyzed using Ingenuity Pathway Analysis (IPA) software. After deriving networks, important molecules were further narrowed down by location within a network. Genes were regarded as central if they had relationships with more than 10 molecules in a network. Protein localization in tissues was confirmed by immunohistochemistry.

RESULTS

Five networks were identified. Their functional annotations were gene expression, cell cycle, growth and proliferation, and cell signaling. Transforming growth factor-beta (TGF-β) was centrally located in the network with the highest IPA score and mothers against decapentaplegic homolog-3 (Smad3) were centrally located in the second highest ranking network. Phosphorylated Smad3 was detected in the nuclei of chondrocytes in immature cartilage.

CONCLUSIONS

Our data suggest the possible importance of Smad3 in the TGF-β signaling in the spontaneous healing of PTCDs in immature rats.

The Role of miRNAs in Cartilage Homeostasis

Osteoarthritis (OA) is an age-related disease with poorly understood pathogenesis. Recent studies have demonstrated that miRNA might play a key role in OA initiation and development. We reviewed recent publications and elucidated the connection between miRNA and OA cartilage anabolic and catabolic signals, including four signaling pathways: TGF-β/Smads and BMPs signaling, associated with cartilage anabolism; and MAPK and NF-KB signaling, associated with cartilage catabolism. We also explored the relationships with MMP, ADAMTS and NOS (NitricOxide Synthases) families, as well as with the catabolic cytokines IL-1 and TNF-α. The potential role of miRNAs in biological processes such as cartilage degeneration, chondrocyte proliferation, and differentiation is discussed. Collective evidence indicates that miRNAs play a critical role in cartilage degeneration. These findings will aid in understanding the molecular network that governs articular cartilage homeostasis and in to elucidate the role of miRNA in the pathogenesis of OA.

Efficacy and tolerability of an undenatured type II collagen supplement in modulating knee osteoarthritis symptoms: a multicenter randomized, double-blind, placebo-controlled study

Background

Undenatured type II collagen (UC-II) is a nutritional supplement derived from chicken sternum cartilage. The purpose of this study was to evaluate the efficacy and tolerability of UC-II for knee osteoarthritis (OA) pain and associated symptoms compared to placebo and to glucosamine hydrochloride plus chondroitin sulfate (GC).

Methods

One hundred ninety one volunteers were randomized into three groups receiving a daily dose of UC-II (40 mg), GC (1500 mg G & 1200 mg C), or placebo for a 180-day period. The primary endpoint was the change in total Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) from baseline through day 180 for the UC-II group versus placebo and GC. Secondary endpoints included the Lequesne Functional Index (LFI), the Visual Analog Scale (VAS) for pain and the WOMAC subscales. Modified intent-to-treat analysis were performed for all endpoints using analysis of covariance and mixed model repeated measures, while incremental area under the curve was calculated by the intent-to-treat method.

Results

At day 180, the UC-II group demonstrated a significant reduction in overall WOMAC score compared to placebo (p = 0.002) and GC (p = 0.04). Supplementation with UC-II also resulted in significant changes for all three WOMAC subscales: pain (p = 0.0003 vs. placebo; p = 0.016 vs. GC); stiffness (p = 0.004 vs. placebo; p = 0.044 vs. GC); physical function (p = 0.007 vs. placebo). Safety outcomes did not differ among the groups.

Conclusion

UC-II improved knee joint symptoms in knee OA subjects and was well-tolerated. Additional studies that elucidate the mechanism for this supplement’s actions are warranted.

Trial registration

CTRI/2013/05/003663; CTRI/2013/02/003348.

Fuyuan Decoction Enhances SOX9 and COL2A1 Expression and Smad2/3 Phosphorylation in IL-1β-Activated Chondrocytes

Fuyuan Decoction (FYD), a herbal formula in China, has been widely used for osteoarthritis (OA) treatment. Herein, we determined the effects of FYD on the expression of transcription factor SOX9 and its target gene collagen type II, alpha 1 (COL2A1) as well as the activation of Smad2/3 in interleukin- (IL-) 1β-stimulated SW1353 chondrosarcoma cells. Serum-derived FYD (FYD-CS) was prepared to treat SW1353 cells with or without SB431542, a TGF-β1 receptor inhibitor. Cell cycle progression was tested by flow cytometry. The expression of SOX9 and COL2A1 and the activation of Smad2/3 (p-Smad2/3) were analyzed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and/or western blot. The results showed that, after treatment, FYD-CS, while inducing S-phase cell cycle arrest, enhanced cell proliferation and protected the cells against IL-1β- and/or SB431542-induced cell growth inhibition. Furthermore, FYD-CS reversed the decreased expression of COL2A1 and SOX9 induced by IL-1β and SB431542 and blocked the decreased phosphorylation of Smad2/3 induced by IL-1β alone or in combination with SB431542. Our results suggest that FYD promotes COL2A1 and SOX9 expression as well as Smad2/3 activation in IL-1β-induced chondrocytes, thus benefiting cell survival.

Positive effects of cell-free porous PLGA implants and early loading exercise on hyaline cartilage regeneration in rabbits

The regeneration of hyaline cartilage remains clinically challenging. Here, we evaluated the therapeutic effects of using cell-free porous poly(lactic-co-glycolic acid) (PLGA) graft implants (PGIs) along with early loading exercise to repair a full-thickness osteochondral defect. Rabbits were randomly allocated to a treadmill exercise (TRE) group or a sedentary (SED) group and were prepared as either a PGI model or an empty defect (ED) model. TRE was performed as a short-term loading exercise; SED was physical inactivity in a free cage. The knees were evaluated at 6 and 12 weeks after surgery. At the end of testing, none of the knees developed synovitis, formed osteophytes, or became infected. Macroscopically, the PGI-TRE group regenerated a smooth articular surface, with transparent new hyaline-like tissue soundly integrated with the neighboring cartilage, but the other groups remained distinct at the margins with fibrous or opaque tissues. In a micro-CT analysis, the synthesized bone volume/tissue volume (BV/TV) was significantly higher in the PGI-TRE group, which also had integrating architecture in the regeneration site. The thickness of the trabecular (subchondral) bone was improved in all groups from 6 to 12 weeks. Histologically, remarkable differences in the cartilage regeneration were visible. At week 6, compared with SED groups, the TRE groups manifested modest inflammatory cells with pro-inflammatory cytokines (i.e., TNF-α and IL-6), improved collagen alignment and higher glycosaminoglycan (GAG) content, particularly in the PGI-TRE group. At week 12, the PGI-TRE group had the best regeneration outcomes, showing the formation of hyaline-like cartilage, the development of columnar rounded chondrocytes that expressed enriched levels of collagen type II and GAG, and functionalized trabecular bone with osteocytes. In summary, the combination of implanting cell-free PLGA and performing an early loading exercise can significantly promote the full-thickness osteochondral regeneration in rabbit knee joint models.

STATEMENT OF SIGNIFICANCE

Promoting effective hyaline cartilage regeneration rather than fibrocartilage scar tissue remains clinically challenging. To address the obstacle, we fabricated a spongy cell-free PLGA scaffold, and designed a reasonable exercise program to generate combined therapeutic effects. First, the implanting scaffold generates an affordable mechanical structure to bear the loading forces and bridge with the host to offer a space in the full-thickness osteochondral regeneration in rabbit knee joint. After implantation, rabbits were performed by an early treadmill exercise 15 min/day, 5 days/week for 2 weeks that directly exerts in situ endogenous growth factor and anti-inflammatory effects in the reparative site. The advanced therapeutic strategy showed that neo-hyaline cartilage formation with enriched collagen type II, higher glycosaminoglycan, integrating subchondral bone formation and modest inflammation.

Cytokines as Mediators of Pain-Related Process in Breast Cancer

Pain is a clinical sign of inflammation found in a wide variety of chronic pathologies, including cancer. The occurrence of pain in patients carrying breast tumors is reported and is associated with aspects concerning disease spreading, treatment, and surgical intervention. The persistence of pain in patients submitted to breast surgery is estimated in a range from 21% to 55% and may affect patients before and after surgery. Beyond the physical compression exerted by the metastatic mass expansion and tissue injury found in breast cancer, inflammatory components that are significantly produced by the host-tumor interaction can significantly contribute to the generation of pain. In this context, cytokines have been studied aiming to establish a cause-effect relationship in cancer pain-related syndromes, especially the proinflammatory ones. Few reports have investigated the relationship between pain and cytokines in women carrying advanced breast cancer. In this scenario, the present review analyzes the main cytokines produced in breast cancer and discusses the evidences from literature regarding its role in specific clinical features related with this pathology.

Nutritional Approach for Relief of Joint Discomfort: A 12-week, Open-case Series and Illustrative Case Report

CONTEXT

Tetrahydro iso-α acids (THIAAs), derived from Humulus lupulus (hops), have demonstrated anti-inflammatory effects in vitro and in an animal model of rheumatoid arthritis (RA). Undenatured type 2 collagen has been found to be effective in clinical studies in RA and osteoarthritis (OA).

OBJECTIVE

The study intended to evaluate the efficacy and safety of a proprietary tablet containing 150 mg of n-enriched THIAA (nTHIAA) and 10 mg of undenatured type 2 collagen (UC-II) (containing 25% UC-II) in patients with arthritis.

DESIGN

The study was an open-label case series. This article also includes a case history for 1 participant.

SETTING

The study was conducted at the Functional Medicine Research Center (FMRC) in Gig Harbor, WA, USA, from February 2013-June 2013.

PARTICIPANTS

Participants were 17 adults, 12 women, and 5 men aged 39-69 y, who had chronic joint pain involving various joints, 13 with probable OA and 4 with possible RA.

INTERVENTION

Participants took 2 tablets of nTHIAA + UC-II 2 ×/d with meals for 12 wk.

OUTCOME MEASURES

Participants completed arthritis-related and quality-of-life questionnaires, at weeks 2, 4, 8, and 12: (1) the visual analog scale for pain (VAS-P); (2) the medical symptoms questionnaire (MSQ), with the analysis particularly focusing on the joint/muscle subscale and total scores; (3) the health and wellness outcome questionnaire (MOS-SF36), with the analysis particularly focusing on the physical and mental subscales; (4) the arthritis impact questionnaire (AIQ), with the analysis particularly focusing on the arthritis symptoms and daily living subscales; (5) the health assessment questionnaire (HAQ-DI) with the analysis particularly focusing on question 26 (Q26), which indicates overall pain during the week prior to the survey; and (6) the arthritis impact measurement scales 2 (AIMS2). At 12 wk, participants also completed the visual analog scale for efficacy (VAS-E).

RESULTS

All participants completed the 12-wk evaluation, and all reported improvements in pain. Significant improvements in scores on the questionnaires were observed as early as 2 wk. For example, the total score on the MSQ was significantly decreased from a mean of 20.76 ± 2.90 (SE) at baseline to 12.24 ± 2.81 after 2 wk (P < .001). At 12 wk, the participants rated the supplement's efficacy at 7.6 ± 0.6 of 10. At baseline, 13 of the 17 participants were using analgesics for joint pain, compared with only 4 participants at 12 wk. Two of those 4 had reduced their analgesic dosages. The studied supplement was well tolerated, and no serious side effects occurred.

CONCLUSIONS

The supplement containing nTHIAA and UC-II is safe and efficacious in participants with chronic joint pain.

Lentiviral vector-mediated over-expression of Sox9 protected chondrocytes from IL-1β induced degeneration and apoptosis

To explore whether the over-expression of Sry-related HMG box (Sox9) in degenerative chondrocytes is able to improve cell regeneration and protects cells from inflammation induced apoptosis, we generated a Sox9 over-expressing vector delivery system in which the Sox9 gene was inserted into a lentiviral vector. After infecting mouse chondrocytes with the Sox9-encoding vector, we observed a high level of gene transduction efficiency and achieved a high level of Sox9 expression in the infected chondrocytes. To explore whether over-expression of Sox9 is able to induce cell regeneration and improve cell survival, we induced Sox9 over-expression by lentiviral vector infection 48 hours before IL-1β treatment. The cells were infected with the reporter gene GFP-encoded lentiviral vector as a negative control or left uninfected. 48-hours after IL-1β treatment, the chrondrocytes treated with IL-1β alone, underwent a degenerative process, with elevated expression of MMP-3, MMP-13, ADAMTS-5 and ALP, but the cell specific anabolic proteins collagen II and aggrecan were significantly suppressed. The cells infected with the GFP reporter vector had no increased regeneration after IL-1β treatment. The results indicated that Sox9 is an important chondrocyte transcription factor, promoting chondrocyte regeneration and cell survival, which were mediated through affecting multiple cell differentiation as well as anti-apoptotic signaling pathways.

Transforming growth factor-β1 induces type II collagen and aggrecan expression via activation of extracellular signal-regulated kinase 1/2 and Smad2/3 signaling pathways

Transforming growth factor (TGF)‑β regulates the anabolic metabolism of articular cartilage and prevents cartilage degradation. TGF‑β1 influences cellular proliferation, differentiation and the extracellular matrix through activation of the extracellular signal‑regulated kinase (ERK)1/2 and Smad2/3 signaling pathways. However, it has remained to be fully elucidated precisely how the ERK1/2 and Smad2/3 signaling pathways mediate anabolic processes of articular cartilage. The present study investigated how ERK1/2 and Smad2/3 signaling mediate TGF‑β1‑stimulated type II collagen and aggrecan expression in rat chondrocytes. The results confirmed that TGF‑β1 stimulates type II collagen and aggrecan expression in rat chondrocytes, and furthermore, that the ERK1/2 and Smad2/3 signaling pathways were activated by TGF‑β1. Conversely, the TGF‑β receptor I (ALK5) kinase inhibitor SB525334 significantly impaired TGF‑β1‑induced type II collagen and aggrecan expression, coinciding with a reduction of ERK1/2 and Smad3 phosphorylation. In addition, TGF‑β1‑induced type II collagen and aggrecan expression were significantly suppressed by ERK1/2 inhibitor PD98059. Similarly, TGF‑β1‑stimulated type II collagen and aggrecan expression were decreased in the presence of a Smad3 phosphorylation inhibitor SIS3. Therefore, the present study demonstrated that the ERK1/2 and Smad2/3 signaling pathways regulate type II collagen and aggrecan expression in rat chondrocytes.

Role of medial abrasion phenomenon in the pathogenesis of knee osteoarthritis

Osteoarthritis of the knee affects a large population worldwide and is associated with an extremely high economic burden largely attributable to the effects of disability, comorbid disease, and the expense of treatment. Since the initiating events that result in the cartilage degradation are poorly understood, there has been very limited success in demonstrating disease modification in clinical trials of potential therapies. Medial plica related medial abrasion phenomenon has recently been identified to have close relationship with medial compartment osteoarthritis. We hypothesized that this abrasion phenomenon will elicit lifelong interplay between pathologic medial plica and the facing medial femoral condyle and might play a role in the pathogenesis of knee osteoarthritis by both physical and chemical effects. After evaluating current evidence, we designed a study to prove that the concentrations of total protein, cartilage degrading related cytokines (tumor necrosis factor-α and interleukin-1β) and enzyme (matrix metalloproteinase-3) are higher in the medial compartment of the knee having the phenomenon of medial abrasion. The accumulating data and findings about medial abrasion phenomenon might be important for the understanding of the pathogenesis or progression of this common disease. We hope that our hypothesis will stimulate further studies verifying if medial abrasion phenomenon plays more roles in the pathogenesis of knee osteoarthritis. Further clinical observations for its appropriate treatment based on this hypothesis are also mandatory for the benefits of patients.

Exercise modulates the expression of IL-1β and IL-10 in the articular cartilage of normal and osteoarthritis-induced rats

After a joint lesion, high-impact exercise is a risk factor for the development of osteoarthritis (OA). The degradation of articular cartilage in OA has been associated with the activation of inflammatory cytokine signaling pathways. However, differences in cytokine expression in healthy and injured cartilage after exercise have not yet been analyzed. We used immunofluorescence and Western blot to study the expression of IL-1β and IL-10 in the articular cartilage of normal (N), sham-operated (S), and menisectomized (OA) rats subjected or not to high-impact exercise (E) for 3, 6, and 10 days (N, NE, S, SE, and OA groups). Cartilage integrity and proteoglycan content were only affected in the OA groups. Exercise increased the amount of IL-1β and IL-10 positive chondrocytes in NE and SE groups compared with non-exercised groups (N and S). The expression of IL-1β was up-regulated over time in the NE and OA groups, although in the late stages the increase was higher in the OA groups. In contrast, the expression of anti-inflammatory IL-10 was low in the OA group, whereas in the NE groups expression levels were higher at each time point analyzed. These results suggest that anti- and pro-inflammatory molecules in the cartilage might be tightly regulated to maintain the integrity of the tissue and that when this equilibrium is broken (when the meniscus is removed), the pro-inflammatory cytokines take over and OA develops.

Calcific Aortic Valve Disease: Molecular Mechanisms and Therapeutic Approaches

Calcification occurs in atherosclerotic vascular lesions and In the aortic valve. Calcific aortic valve disease (CAVD) is a slow, progressive disorder that ranges from mild valve thickening without obstruction of blood flow, termed aortic sclerosis, to severe calcification with impaired leaflet motion, termed aortic stenosis. In the past, this process was thought to be 'degenerative' because of time-dependent wear and tear of the leaflets, with passive calcium deposition. The presence of osteoblasts in atherosclerotic vascular lesions and in CAVD implies that calcification is an active, regulated process akin to atherosclerosis, with lipoprotein deposition and chronic inflammation. If calcification is active, via pro-osteogenic pathways, one might expect that development and progression of calcification could be inhibited. The overlap in the clinical factors associated with calcific valve disease and atherosclerosis provides further support for a shared disease mechanism. In our recent research we used an in vitro porcine valve interstitial cell model to study spontaneous calcification and potential promoters and inhibitors. Using this model, we found that denosumab, a human monoclonal antibody targeting the receptor activator of nuclear factor-κB ligand may, at a working concentration of 50 μg/mL, inhibit induced calcium deposition to basal levels.

Using Na3PO4 to Enhance In vitro Animal Models of Aortic Valve Calcification

BACKGROUND/OBJECTIVES

The pathogenesis of calcific aortic valvular disease (CAVD) involves an active inflammatory process of valvular interstitial cells (VICs) characterized by the activation of specific osteogenic signaling pathways and apoptosis. This process can be studied by analyzing certain molecular markers and gene expression pathways of spontaneous calcification. The purpose of our study is to investigate the role of sodium phosphate (Na3PO4) as a calcification promoter, with the aim of improving in vitro animal models for testing potential calcification inhibitors.

MATERIALS AND METHODS

VICs were extracted from 6 healthy 6-month-old fresh porcine hearts by serial collagenase digestion. Quantitative polymerase chain reaction (qPCR) was used to quantify trans-differentiation of genes of interest during spontaneous calcification of VICs. Spontaneous calcification of VICs was increased by adding Na₃PO₄ (3 mM, pH 7.4). The degree of calcification was estimated by Alizarin Red staining for calcium deposition, and Sirius Red staining for collagen. Colorimetric techniques were used to determine calcium and collagen deposition quantitatively. Additionally, the enzymatic activity of alkaline phosphatase (ALP) was measured by a kinetic assay. For statistical analysis we used SPSS and Microsoft Office Excel 2013.

RESULTS

Porcine VICs calcify spontaneously with demonstrable calcium and collagen deposition. In this study we observed an increase of calcium and collagen deposition from day 0 to day 14 (calcium: 376%; P<0.001, collagen: 3553%; P<0.001). qPCR analysis of mRNA by day 14 showed the following results: α-actin, a marker of myoblast phenotype, was increased to 1.6-fold; P<0.001. Runx2, an osteoblast marker, rose to 1.3 fold; P<0.05, TGF-β, a promoter of osteogenesis, increased to 3.2-fold; P<0.001, and RhoA, a regulator of nodular formation in myoblasts, increased to 4.5-fold; P<0.001, compared to their levels at day 0. RANKL mRNA and calponin did not change significantly. Treatment of porcine VICs with Na3PO4 (3 mM, pH 7.4) led to a marked increase in calcium deposition by day 14 (522%; P<0.001), and a significant increase in ALP activity by day 7 (228%; P<0.05). There were no significant changes in ALP activity between the groups by day 14.

CONCLUSION

This study has demonstrated the upregulation of some specific molecules during spontaneous calcification of aortic VICs with an active increase of calcium, collagen and ALP activity. In this in vitro model it was possible to increase spontaneous VICs calcification with Na₃PO₄ (3 mM, pH 7.4) to a level in which inhibitors of calcification could be tested to identify a novel potential therapeutic strategy against calcific aortic stenosis.

Effects of Adipokines and Insulin on Intracellular pH, Calcium Concentration, and Responses to Hypo-Osmolarity in Human Articular Chondrocytes from Healthy and Osteoarthritic Cartilage

OBJECTIVE

To evaluate the effects of adipokines and insulin on intracellular calcium concentration ([Ca(2+)]i) and pH (pHi) in human articular chondrocytes from healthy (CHC) and osteoarthritic cartilage (COC).

DESIGN

pHi and [Ca(2+)]i were measured using BCECF and Fura-2 fluorometric probes in CHC and COC under control conditions and following a hypotonic shock. The effects of interleukin-1β (IL1β), tumor necrosis factor-α (TNFα), insulin, leptin, resistin, and adiponectin were assessed.

RESULTS

pHi was lower in COC than in CHC. Only IL1β β decreased pHi in both cell types; all the agents enhanced pHi recovery following an ammonium prepulse in CHC, effect that was attenuated by Na(+)-H(+) exchanger inhibitors, but they had no effect in COC. Hypotonic shock (HTS) caused a pHi increase, which was significantly smaller in COC. All the hormones attenuated this response and the effect of IL1β was greater. The basal [Ca(2+)]i was similar in COC and CHC; IL1β, TNFα, and insulin increased the [Ca(2+)]i, but leptin, resistin, and adiponectin did not. These effects were greater in COC. This [Ca(2+)]i increase was dependent on extracellular Ca(2+) and attenuated by Na(+)-Ca(2+) exchanger inhibitors. HTS caused a [Ca(2+)]i increase, which was inhibited by transient receptor potential vanilloid blockers and attenuated by all the hormones tested with the exception of adiponectin.

CONCLUSIONS

These findings may help explain the association between obesity and osteoarthritis, in which these hormones are altered. The responses of CHC and COC are different, which suggests that a modification of pH and Ca(2+) homeostasis is part of the osteoarthritis pathophysiology.