Matrix metalloproteinases in arthritic disease

Effect of the novel anti-NGF monoclonal antibody DS002 on the metabolomics of pain mediators, cartilage and bone

The anti-nerve growth factor antibody class of drugs interrupts signaling by blocking NGF binding to TrkA receptors for the treatment of pain; however, this target class of drugs has been associated with serious adverse effects in the joints during clinical trials. DS002 is a novel anti-nerve growth factor antibody drug independently developed by Guangdong Dashi Pharmaceuticals. The main purpose of this study is to explore the correlation between DS002 and pain as well as cartilage and bone metabolism with the help of metabolomics technology and the principle of enzyme-linked reaction, and to examine whether DS002 will produce serious adverse effects in joints caused by its same target class of drugs, in order to provide more scientific basis for the safety and efficacy of DS002. Our results showed that DS002 mainly affected the metabolism of aromatic amino acids and other metabolites, of which six metabolites, l -phenylalanine, 5-hydroxytryptophan, 5-hydroxytryptamine hydrochloride, 3-indolepropionic acid, kynuric acid, and kynurenine, were significantly altered, which may be related to the effectiveness of DS002 in treating pain. In addition, there were no significant changes in biological indicators related to cartilage and bone metabolism in vivo, suggesting that DS002 would not have a significant effect on cartilage and bone metabolism, so we hypothesize that DS002 may not produce the serious adverse effects in joints caused by its fellow target analogs. Therefore, the Anti-NGF analgesic drug DS002 has the potential to become a promising drug in the field of analgesia, providing pain patients with an efficient treatment option without adverse effects.

Unveiling the bioinformatic genes and their involved regulatory mechanisms in type 2 diabetes combined with osteoarthritis

Background

Type 2 Diabetes Mellitus (T2D) and Osteoarthritis (OA) are both prevalent diseases that significantly impact the health of patients. Increasing evidence suggests that there is a big correlation between T2D and OA, but the molecular mechanisms remain elusive. The aims of this study are to investigate the shared biomarkers and potential molecular mechanisms in T2D combined with OA.

Methods

T2D and OA-related differentially expressed genes (DEGs) were identified via bioinformatic analysis on Gene Expression Omnibus (GEO) datasets GSE26168 and GSE114007 respectively. Subsequently, extensive target prediction and network analysis were finished with Gene Ontology (GO), protein-protein interaction (PPI), and pathway enrichment with DEGs. The transcription factors (TFs) and miRNAs coupled in co-expressed DEGs involved in T2D and OA were predicted as well. The key genes expressed both in the clinical tissues of T2D and OA were detected with western blot and qRT-PCR assay. Finally, the most promising candidate compounds were predicted with the Drug-Gene Interaction Database (DGIdb) and molecular docking.

Results

In this study, 209 shared DEGs between T2D and OA were identified. Functional analysis disclosed that these DEGs are predominantly related to ossification, regulation of leukocyte migration, extracellular matrix (ECM) structural constituents, PI3K/AKT, and Wnt signaling pathways. Further analysis via Protein-Protein Interaction (PPI) analysis and validation with external datasets emphasized MMP9 and ANGPTL4 as crucial genes in both T2D and OA. Our findings were validated through qRT-PCR and Western blot analyses, which indicated high expression levels of these pivotal genes in T2D, OA, and T2D combined with OA cases. Additionally, the analysis of Transcription Factors (TFs)-miRNA interactions identified 7 TFs and one miRNA that jointly regulate these important genes. The Receiver Operating characteristic (ROC) analysis demonstrated the significant diagnostic potential of MMP9 and ANGPTL4.Moreover, we identified raloxifene, ezetimibe, and S-3304 as promising agents for patients with both T2D and OA.

Conclusion

This study uncovers the shared signaling pathways, biomarkers, potential therapeutics, and diagnostic models for individuals suffering from both T2D and OA. These findings not only present novel perspectives on the complex interplay between T2D and OA but also hold significant promise for improving the clinical management and prognosis of patients with this concurrent condition.

The role of inflammatory mediators and matrix metalloproteinases (MMPs) in the progression of osteoarthritis

Osteoarthritis (OA) is a chronic musculoskeletal disorder characterized by an imbalance between (synthesis) and catabolism (degradation) in altered homeostasis of articular cartilage mediated primarily by the innate immune system. OA degenerates the joints resulting in synovial hyperplasia, degradation of articular cartilage with damage of the structural and functional integrity of the cartilage extracellular matrix, subchondral sclerosis, osteophyte formation, and is characterized by chronic pain, stiffness, and loss of function. Inflammation triggered by factors like biomechanical stress is involved in the development of osteoarthritis. In OA apart from catabolic effects, anti-inflammatory anabolic processes also occur continually. There is also an underlying chronic inflammation present, not only in cartilage tissue but also within the synovium, which perpetuates tissue destruction of the OA joint. The consideration of inflammation in OA considers synovitis and/or other cellular and molecular events in the synovium during the progression of OA. In this review, we have presented the progression of joint degradation that results in OA. The critical role of inflammation in the pathogenesis of OA is discussed in detail along with the dysregulation within the cytokine networks composed of inflammatory and anti-inflammatory cytokines that drive catabolic pathways, inhibit matrix synthesis, and promote cellular apoptosis. OA pathogenesis, fluctuation of synovitis, and its clinical impact on disease progression are presented here along with the role of synovial macrophages in promoting inflammatory and destructive responses in OA. The role of interplay between different cytokines, structure, and function of their receptors in the inter-cellular signaling pathway is further explored. The effect of cytokines in the increased synthesis and release of matrix-decomposing proteolytic enzymes, such as matrix metalloproteinase (MMPs) and a disintegrin-like and metalloproteinase with thrombospondin motif (ADAMTS), is elaborated emphasizing the potential impact of MMPs on the chondrocytes, synovial cells, articular and periarticular tissues, and other immune system cells migrating to the site of inflammation. We also shed light on the pathogenesis of OA via oxidative damage particularly due to nitric oxide (NO) via its angiogenic response to inflammation. We concluded by presenting the current knowledge about the tissue inhibitors of metalloproteinases (TIMPs). Synthetic MMP inhibitors include zinc binding group (ZBG), non-ZBG, and mechanism-based inhibitors, all of which have the potential to be therapeutically beneficial in the treatment of osteoarthritis. Improving our understanding of the signaling pathways and molecular mechanisms that regulate the MMP gene expression, may open up new avenues for the creation of therapies that can stop the joint damage associated with OA.

Translation of cell therapies to treat autoimmune disorders

Autoimmune diseases are a diverse and complex set of chronic disorders with a substantial impact on patient quality of life and a significant global healthcare burden. Current approaches to autoimmune disease treatment comprise broadly acting immunosuppressive drugs that lack disease specificity, possess limited efficacy, and confer undesirable side effects. Additionally, there are limited treatments available to restore organs and tissues damaged during the course of autoimmune disease progression. Cell therapies are an emergent area of therapeutics with the potential to address both autoimmune disease immune dysfunction as well as autoimmune disease-damaged tissue and organ systems. In this review, we discuss the pathogenesis of common autoimmune disorders and the state-of-the-art in cell therapy approaches to (1) regenerate or replace autoimmune disease-damaged tissue and (2) eliminate pathological immune responses in autoimmunity. Finally, we discuss critical considerations for the translation of cell products to the clinic.

Poly-beta-amino-ester licofelone conjugates development for osteoarthritis treatment

Disease-modifying osteoarthritis drugs (DMOADs) are a new therapeutic class for osteoarthritis (OA) prevention or inhibition of the disease development. Unfortunately, none of the DMOADs have been clinically approved due to their poor therapeutic performances in clinical trials. The joint environment has played a role in this process by limiting the amount of drug effectively delivered as well as the time that the drug stays within the joint space. The current study aimed to improve the delivery of the DMOADs into cartilage tissue by increasing uptake and retention time of the DMOADs within the tissue. Licofelone was used a model DMOAD due to its significant therapeutic effect against OA progression as shown in the recent phase III clinical trial. For this purpose licofelone was covalently conjugated to the two different A16 and A87 poly-beta-amino-ester (PBAEs) polymers taking advantage of their hydrolysable, cytocompatible, and cationic nature. We have shown cartilage uptake of the licofelone-PBAE conjugates increased 18 times and retention in tissues was prolonged by 37 times compared to the equivalent dose of the free licofelone. Additionally, these licofelone conjugates showed no detrimental effect on the chondrocyte viability. In conclusion, the cationic A87 and A16 PBAE polymers increased the amount of licofelone within the cartilage, which could potentially enhance the therapeutic effect and pharmacokinetic performance of this drug and other DMOADs clinically.

GDF8 inhibition enhances musculoskeletal recovery and mitigates posttraumatic osteoarthritis following joint injury

Musculoskeletal disorders contribute substantially to worldwide disability. Anterior cruciate ligament (ACL) tears result in unresolved muscle weakness and posttraumatic osteoarthritis (PTOA). Growth differentiation factor 8 (GDF8) has been implicated in the pathogenesis of musculoskeletal degeneration following ACL injury. We investigated GDF8 levels in ACL-injured human skeletal muscle and serum and tested a humanized monoclonal GDF8 antibody against a placebo in a mouse model of PTOA (surgically induced ACL tear). In patients, muscle GDF8 was predictive of atrophy, weakness, and periarticular bone loss 6 months following surgical ACL reconstruction. In mice, GDF8 antibody administration substantially mitigated muscle atrophy, weakness, and fibrosis. GDF8 antibody treatment rescued the skeletal muscle and articular cartilage transcriptomic response to ACL injury and attenuated PTOA severity and deficits in periarticular bone microarchitecture. Furthermore, GDF8 genetic deletion neutralized musculoskeletal deficits in response to ACL injury. Our findings support an opportunity for rapid targeting of GDF8 to enhance functional musculoskeletal recovery and mitigate the severity of PTOA after injury.

Correlation Between Synovial Fluid Levels of Matrix Metalloproteinase's (MMP-1, MMP-3, and MMP-9) and TNF-α with the Severity of Osteoarthritis Knee in Rural Indian Population

Background

In India, 22% to 39% of the ageing population suffers from degenerative knee osteoarthritis (OA), making it the most prevalent joint disorder in the knee. MMP-1, MMP-3, and MMP-9 protein expression levels have all been associated with OA. The aim of the present study was to establish a relationship between synovial fluid levels of matrix metalloproteinases (MMP-1, MMP-3, and MMP-9), and tumour necrosis factor-alpha (TNF-α) with different Kellgren-Lawrence Grading scale as per the severity of knee osteoarthritis (OA).

Methods

This hospital-based observational study included 87 individuals with knee osteoarthritis examined at the orthopaedics department outpatient clinic at the tertiary care teaching hospital in rural area of north India. In-person interviews were conducted to gather data, through a semi-structured, pretested interview schedule. To determine the degree and severity of OA, the levels of the enzymes matrix metalloproteinase MMP-1, MMP-3, and MMP-9 as well as tumour necrosis factor (TNF-α) were assessed in the synovial fluid of knee of each study participant.

Results

The levels of MMP-1, MMP-3, MMP-9, and TNF-α in synovial fluid were significantly correlated with the severity of osteoarthritis as determined by the Kellgren-Lawrence Grading Scale. Age, duration of symptoms and BMI showed a strong positive and significant correlation with biochemical markers (MMP-1, MMP-3, MMP-9, and TNF-α) in synovial fluid of Knee.

Conclusion

Level of biochemical markers (MMP-1, -3, -9, and TNF-α) in synovial fluid act as diagnostic markers and have a positive correlation with the severity of osteoarthritis knee, age, weight/BMI and duration of disease. However, no significant correlation was found between the level of aforementioned biochemical markers with sex, height, inflammation of the knee, morning stiffness, and age of onset of disease.

Osteoarthritis improvement effect of Chrysanthemum zawadskii var. latilobum extract in relation to genotype

Objectives: To determine whether SNPs of osteoarthritis (OA)-related genes predict the effect of Chrysanthemum zawadskii var. latilobum (CZ) extract in OA patients with OA. Subjects/methods: To analyze correlations between CZ extract effects in humans and their genotypes, 121 Korean patients with OA were recruited. Patients ingested 600 mg/day of the CZ extract GCWB106 (one tablet daily), including 250-mg CZ, or placebo (one tablet daily) for 12 weeks. Twenty SNPs were genotyped in 11 genes associated with OA pathogenesis, including tumor necrosis factor-alpha (TNF-α) and matrix metalloproteinases (MMPs), and 9 genes involved in OA-related dietary intervention. The Visual Analogue Scale (VAS) and Korean Western Ontario and McMaster Universities (K-WOMAC) were measured as indicators of GCWB106 effect. Statistical comparisons were performed using Kruskal-Wallis tests to identify associations between these scales and genotyped loci in patients with OA. Results: Three SNPs (PPARG rs3856806, MMP13 rs2252070, and ZIP2 rs2234632) were significantly associated with the degree of change in VAS pain score. Homozygous CC genotype carriers of rs3856806, G allele carriers (GA or GG) of rs2252070, and T allele carriers (GT or TT) of rs2234632 showed lower VAS score (i.e., less severe symptoms) in the GCWB106 group (n=53) than the placebo group (n=57) (p=0.026, p=0.009, and p=0.025, respectively). Gene-gene interaction effects on GCWB106-mediated pain relief were then examined, and it was found that the addition of each genotype resulted in a greater decrease in VAS pain score in the GCWB106 group (p=0.0024) but not the placebo group (p=0.7734). Conclusions: These novel predictive markers for the pain-relieving effects of GCWB106 may be used in the personalized treatment of patients with OA.

Bromelain: a review of its mechanisms, pharmacological effects and potential applications

The utilization of plant-derived supplements for disease prevention and treatment has long been recognized because of their remarkable potential. Ananas comosus, commonly known as pineapple, produces a group of enzymes called bromelain, which contains sulfhydryl moieties. Recent studies have shown that bromelain exhibits a wide range of activities, including anti-inflammatory, anti-diabetic, anti-cancer, and anti-rheumatic properties. These properties make bromelain a promising drug candidate for the treatment of various diseases. The anti-inflammatory activity of bromelain has been shown to be useful in treating inflammatory conditions such as osteoarthritis, rheumatoid arthritis, and asthma, whereas the anti-cancer activity of bromelain is via induction of apoptosis, inhibition of angiogenesis, and enhancement of the body's immune response. The anti-diabetic property of bromelain is owing to the improvement in glucose metabolism and reduction in insulin resistance. The therapeutic potential of bromelain has been investigated in numerous preclinical and clinical studies and a number of patents have been granted to date. Various formulations and delivery systems are being developed in order to improve the efficacy and safety of this molecule, including the microencapsulated form to treat oral inflammatory conditions and liposomal formulations to treat cancer. The development of novel drug delivery systems and formulations has further ameliorated the therapeutic potential of bromelain by improving its bioavailability and stability, while reducing the side effects. This review intends to discuss various properties and therapeutic applications of bromelain, along with its possible mechanism of action in treating various diseases. Recent patents and clinical trials concerning bromelain have also been covered.

Carboxyamidotriazole alleviates pannus formation and cartilage erosion in rats with adjuvant arthritis

Carboxyamidotriazole (CAI) was initially considered a non-cytotoxic anticancer agent. However, recently, pronounced anti-inflammatory properties of CAI have been reported. Rheumatoid arthritis (RA) is an autoimmune inflammatory disease characterized by aberrant activation of signaling pathways. Therefore, this study explored the therapeutic effects and potential mechanism of action of CAI on RA in the adjuvant arthritis (AA) model. The results showed that CAI reduced the severity of arthritis in AA rats as demonstrated by inhibited hind paw swelling, reduced body weight, and decreased infiltration of joint pathological inflammatory cells. Importantly, pathological scoring of new blood vessels and immunohistochemical assays revealed that CAI inhibited pannus formation. CAI decreased the expression of pro-angiogenic growth factors, such as vascular epidermal growth factor, basic fibroblast growth factor, and metalloproteinases (MMPs), namely, MMP-1 and MMP-3 in the synovium of AA rats. Furthermore, CAI significantly reduced the increased levels of phosphorylated p38, c-Jun N-terminal kinase (JNK)1/2, and extracellular signal-regulated kinase (ERK)1/2 proteins in AA rats. In addition, the proliferation of fibroblast-like synoviocytes (FLS) was downregulated by CAI both in vivo and in vitro. In conclusion, this investigation illustrates the therapeutic effect of CAI on synovitis and erosion of articular cartilage in RA. Furthermore, the mechanism might involve inhibition of aberrantly activated mitogen-activated protein kinase signaling, as well as a decrease in pro-angiogenic factors, MMP expression, and FLS proliferation.

Matrix metalloproteinases in arthritis: towards precision medicine

Proteolysis of structural molecules of the extracellular matrix (ECM) is an irreversible post-translational modification in all arthropathies. Common joint disorders, including osteoarthritis and rheumatoid arthritis, have been associated with increased levels of matrix remodelling enzymes, including matrix metalloproteinases (MMPs). MMPs, in concert with other host proteinases and glycanases, destroy proteoglycans, collagens and other ECM molecules. MMPs may also control joint remodelling indirectly by signalling through cell-surface receptors or by proteolysis of cytokines and receptor molecules. After synthesis as pro-forms, MMPs can be activated by various types of post-translational modifications, including proteolysis. Once activated, MMPs are controlled by general and specific tissue inhibitors of metalloproteinases (TIMPs). In rheumatoid arthritis, proteolysis of the ECM results in so-called remnant epitopes that enhance and perpetuate autoimmune processes in susceptible hosts. In osteoarthritis, the considerable production of MMP-13 by chondrocytes, often concurrent with mechanical overload, is a key event. Hence, information about the regulation, timing, localization and activities of MMPs in specific disease phases and arthritic entities will help to develop better diagnostics. Insights into beneficial and detrimental effects of MMPs on joint tissue inflammation are also necessary to plan and execute (pre)clinical studies for better therapy and precision medicine with MMP inhibitors. With the advances in proteomics and single-cell transcriptomics, two critical points need attention: neglected neutrophil MMP biology, and the analysis of net proteolytic activities as the result of balances between MMPs and their inhibitors.

Targeting B7-H3-A Novel Strategy for the Design of Anticancer Agents for Extracranial Pediatric Solid Tumors Treatment

Recent scientific data recognize the B7-H3 checkpoint molecule as a potential target for immunotherapy of pediatric solid tumors (PSTs). B7-H3 is highly expressed in extracranial PSTs such as neuroblastoma, rhabdomyosarcoma, nephroblastoma, osteosarcoma, and Ewing sarcoma, whereas its expression is absent or very low in normal tissues and organs. The influence of B7-H3 on the biological behavior of malignant solid neoplasms of childhood is expressed through different molecular mechanisms, including stimulation of immune evasion and tumor invasion, and cell-cycle disruption. It has been shown that B7-H3 knockdown decreased tumor cell proliferation and migration, suppressed tumor growth, and enhanced anti-tumor immune response in some pediatric solid cancers. Antibody-drug conjugates targeting B7-H3 exhibited profound anti-tumor effects against preclinical models of pediatric solid malignancies. Moreover, B7-H3-targeting chimeric antigen receptor (CAR)-T cells demonstrated significant in vivo activity against different xenograft models of neuroblastoma, Ewing sarcoma, and osteosarcoma. Finally, clinical studies demonstrated the potent anti-tumor activity of B7-H3-targeting antibody-radioimmunoconjugates in metastatic neuroblastoma. This review summarizes the established data from various PST-related studies, including in vitro, in vivo, and clinical research, and explains all the benefits and potential obstacles of targeting B7-H3 by novel immunotherapeutic agents designed to treat malignant extracranial solid tumors of childhood.

Effect study of exosomes derived from platelet-rich plasma in the treatment of knee cartilage defects in rats

BACKGROUND

The repair of articular cartilage defects has always been a difficult problem. We aimed to investigate the therapeutic effect of intra-articular injection of platelet-rich plasma (RPR) and PRP-derived exosomes (PRP-Exos) on cartilage defects in rat knee joints and then provide experience for the use of PRP-exos in cartilage defect repair.

METHODS

Rat abdominal aortic blood was collected, and PRP was extracted by two-step centrifugation. PRP-exos were obtained by kit extraction, and PRP-exos were identified by various methods. After the rats were anesthetized, a cartilage defect subchondral bone was created at the proximal end of the origin of the femoral cruciate ligament with a drill. SD rats were divided into 4 groups, including PRP group, 50 μg/ml PRP-exos group, 5 μg/ml PRP-exos group, and control group. One week after the operation, 50 μg/ml PRP, 50 μg/ml PRP-exos, 5 μg/ml PRP-exos and normal saline were injected into the knee joint cavity of rats in each group, once a week. A total of two injections were given. On the 5th and 10th week after drug injection, the serum levels of matrix metalloproteinase 3 (MMP-3) and tissue inhibitor of matrix metalloproteinase 1 (TIMP-1) were detected by each treatment method, respectively. The rats were killed at the 5th and 10th weeks, respectively, and the cartilage defect repair was observed and scored. The defect repair tissue sections were used for HE staining and type II collagen immunohistochemical staining.

RESULTS

The histological results showed that both PRP-exos and PRP could promote cartilage defect repair and type II collagen formation, and the promoting effect of PRP-exos was significantly better than that of PRP. In addition, enzyme-linked immunosorbent assay (ELISA) results showed that compared with PRP, PRP-exos could significantly increase serum TIMP-1 and decrease serum MMP-3 in rats. And the promoting effect of PRP-exos was concentration dependent.

CONCLUSION

Intra-articular injection of PRP-exos and PRP can promote the repair of articular cartilage defects, and the therapeutic effect of PRP-exos is better than the same concentration of PRP. PRP-exos are expected to be an effective treatment for cartilage repair and regeneration.

Mesenchymal stem cells-derived microvesicles versus platelet-rich plasma in the treatment of monoiodoacetate-induced temporomandibular joint osteoarthritis in Albino rats

Temporomandibular joint osteoarthritis (TMJ-OA) is a serious disease, designated by severe joint pain and dysfunction. Limitations of current therapeutics have led to an increased interest in regenerative strategies. Recently, the non-surgical treatment of OA has seen increased use of biologic injectable therapies like mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP). Although these biotherapies represent an admirable effort, more studies are necessary to determine their efficacy. Thus, the aim of this study was to assess the curative potential of a single intra-articular injection of bone marrow MSCs-derived microvesicles (BM-MSCs-MVs) versus a single intra-articular injection of PRP in monoiodoacetate (MIA)-induced TMJ-OA model in Albino rats. Forty-eight male rats were used. A single intra-articular unilateral MIA injection was utilized to induce TMJ-OA. One week post induction, rats were sorted into 3 groups (16 rats each): group (I): received no treatment, groups (II) & (III): received BM-MSCs-MVs and PRP respectively. Scarification was done at 2 and 4 weeks from onset of treatment. Histological changes of the condylar TMJ were examined with H&E staining. Expression of IL-1β, TNF-α, NF-κB, MMP-13, MMP-3, and collagen ΙΙ markers was detected using real-time PCR. Histologically, the osteoarthritic group exhibited degenerated condylar tissues which were aggravated at 4 weeks. Oppositely, a marked improvement in the condylar TMJ histology was noticed in both the BM-MSCs-MVs-and PRP-treated groups at both time intervals. Additionally, the treated groups showed a decrease in IL-1β, TNF-α, NF-κB, MMP-13 and MMP-3 and an increase in collagen ΙΙ genes expression in contrast to the untreated group. Moreover, this difference was significant in the BM-MSCs-MVs group as compared to the PRP-treated group. Our results concluded that BM-MSCs-MVs as well as PRP treatments were able to target the key pathological features in OA, mainly inflammation and matrix degradation, and helped in restoring condylar structure in TMJ-OA rat model. However, BM-MSCs-MVs treatment exhibited more efficient therapeutic potential as compared to PRP treatment.

Photobiomodulation effects in metalloproteinases expression in zymosan-induced arthritis

Matrix metalloproteinases (MMPs) play a crucial role in the degenerative course of rheumatic disorders. They are responsible for cartilage and other joint-associated tissues breakdown. Amid arthritis treatments, photobiostimulation (PBM), a non-thermal and non-invasive low-power laser application, appears to be an outstanding therapy alternative once it has succeeded in MMPs modulation. Thus, this study aimed to evaluate the PBM effects of low infrared laser (830 nm), testing two different energy densities (3 and 30 Jcm^-2) in MMP-2, MMP-9, MMP-13, and MMP-14 as well as the inhibitor TIMP-2 expressions using zymosan-induced arthritis model. C57BL/6 mice were distributed into four groups (n = 8): zymosan-induced arthritis without treatment; zymosan-induced arthritis and dexamethasone-treated; zymosan-induced arthritis and PBM at energy density of 3 Jcm^-2 treated; and zymosan-induced arthritis and PBM at energy density of 30 Jcm^-2 treated. MMPs and TIMP-2 mRNA relative levels by qRT-PCR and proteins expression by immunohistochemical and Western blotting techniques were performed after PBM treatment in the inflamed joint. Our results demonstrated PBM could modulate both mRNA relative levels and proteins expression of the MMP-2, -9, -13, -14, and TIMP-2 in joint tissues, decreasing MMP-9 protein expression and increasing TIMP-2 protein expression. PBM promotes a better arthritis prognostic, modulating metalloproteinase and its inhibitor, especially MMP-9 and TIMP-2 protein expression that is important inflammatory markers. These findings may also corroborate that PBM may regulate MMPs expression using different pathways.

A systematic review on the potential value of synovial fluid biomarkers to predict clinical outcomes in cartilage repair treatments

OBJECTIVE

Multiple biochemical biomarkers have been previously investigated for the diagnosis, prognosis and response to treatment of articular cartilage damage, including osteoarthritis (OA). Synovial fluid (SF) biomarker measurement is a potential method to predict treatment response and effectiveness. However, the significance of different biomarkers and their correlation to clinical outcomes remains unclear. This systematic review evaluated current SF biomarkers used in investigation of cartilage degeneration or regeneration in the knee joint and correlated these biomarkers with clinical outcomes following cartilage repair or regeneration interventions.

METHOD

PubMed, Institute of Science Index, Scopus, Cochrane Central Register of Controlled Trials, and Embase databases were searched. Studies evaluating SF biomarkers and clinical outcomes following cartilage repair intervention were included. Two researchers independently performed data extraction and Quality Assessment of Diagnostic Accuracy Score 2 (QUADAS-2) analysis. Biomarker inclusion, change following intervention and correlation with clinical outcome was compared.

RESULTS

9 studies were included. Study heterogeneity precluded meta-analysis. There was significant variation in sampling and analysis. 33 biomarkers were evaluated in addition to microRNA and catabolic/anabolic ratios. Five studies reported on correlation of biomarkers with six biomarkers significantly correlated with clinical outcomes following intervention. However, correlation was only demonstrated in isolated studies.

CONCLUSION

This review demonstrates significant difficulties in drawing conclusions regarding the importance of SF biomarkers based on the available literature. Improved standardisation for collection and analysis of SF samples is required. Future publications should also focus on clinical outcome scores and seek to correlate biomarkers with progression to further understand the significance of identified markers in a clinical context.

REGISTRATION NUMBER

PROSPERO CRD42022304298. Study protocol available on PROSPERO website.

Protective Effect of Resveratrol on Knee Osteoarthritis and its Molecular Mechanisms: A Recent Review in Preclinical and Clinical Trials

Osteoarthritis (OA) is one of the progressing chronic joint associated with by many complex factors such as age, obesity, and trauma. Knee osteoarthritis (KOA) is the most common type of OA. KOA is characterized by articular cartilage destruction and degeneration, synovial inflammation, and abnormal subchondral bone changes. To date, no practical clinical approach has been able to modify the pathological progression of KOA. Drug therapy is limited to pain control and may lead to serious side effects when taken for a long time. Therefore, searching for safer and more reliable treatments has become necessary. Interestingly, more and more research has focused on natural products, and monomeric compounds derived from natural products have received much attention as drug candidates for KOA treatment. Resveratrol (RES), a natural phenolic compound, has various pharmacological and biological activities, including anti-cancer, anti-apoptotic, and anti-decay. Recently, studies on the effects of RES on maintaining the normal homeostasis of chondrocytes in KOA have received increasing attention, which seems to be attributed to the multi-targeted effects of RES on chondrocyte function. This review summarizes preclinical trials, clinical trials, and emerging tissue engineering studies of RES for KOA and discusses the specific mechanisms by which RES alleviates KOA. A better understanding of the pharmacological role of RES in KOA could provide clinical implications for intervention in the development of KOA.

Studying molecular signaling in major angiogenic diseases

The growth of blood vessels from already existing vasculature is angiogenesis and it is one of the fundamental processes in fetal development, tissue damage or repair, and the reproductive cycle. In a healthy person, angiogenesis is regulated by the balance between pro- and anti-angiogenic factors. However, when the balance is disturbed, it results in various diseases or disorders. The angiogenesis pathway is a sequential cascade and differs based on the stimuli. Therefore, targeting one of the factors involved in the process can help us find a therapeutic strategy to treat irregular angiogenesis. In the past three decades of cancer research, angiogenesis has been at its peak, where an anti-angiogenic agent inhibiting vascular endothelial growth factor acts as a promising substance to treat cancer. In addition, cancer can be assessed based on the expression of angiogenic factors and its response to therapies. Angiogenesis is important for all tissues, which might be normal or pathologically changed and occur through ages. In clinical therapeutics, target therapy focusing on discovery of novel anti-angiogenic agents like bevacizumab, cetuximab, sunitinib, imatinib, lenvatinib, thalidomide, everolimus etc., to block or inhibit the angiogenesis pathway is well explored in recent times. In this review, we will discuss about the molecular signaling pathways involved in major angiogenic diseases in detail.

Emerging proteoglycans and proteoglycan-targeted therapies in rheumatoid arthritis

Rheumatoid arthritis (RA) is a common auto-immune disease-causing inflammation of the joints and damage of the cartilage and bone. The pathogenesis of RA is characterized in many patients by the presence of antibodies against citrullinated proteins. In the joints, proteoglycans are key structural elements of extracellular matrix in the articular cartilage and synovium and are secreted as lubricants in the synovial fluid. Alterations of proteoglycans contribute to mechanism of disease in RA. Proteoglycans such as aggrecan can be citrullinated and become potential targets of the rheumatoid auto-immune response. Proteoglycans are also up-regulated in RA joints and/or undergo alterations of their regulatory functions over cytokines and chemokines, which promotes inflammation and bone damage. Recent studies have aimed to not only clarify these mechanisms but also develop novel proteoglycan-modulating therapeutics. These include agents altering the function and signaling of proteoglycans as well as tolerizing agents based on citrullinated aggrecan. This mini-review summarizes the most recent findings regarding the dysregulation of proteoglycans that contributes to RA pathogenesis and the potential for proteoglycan-modulating agents to improve RA therapy.

The protective effect of mangiferin on osteoarthritis: An in vitro and in vivo study

Mangiferin is a kind of polyphenol chemical compound separated from these herbal medicines of Mangifera indica L., Anemarrhena asphodeloides Bge. and Belamcanda chinensis L., which has anti-inflammatory, anti-virus, and other physiological activities without toxic effects. Osteoarthritis (OA) is a chronic disease that is also a kind of arthritis disease in which articular cartilage or bones under the joint is damaged. In addition, artificial replacements are required in severe cases. At present, there are not too much researches on the potential biological activities of mangiferin that plays a protective role in the treatment of OA. In this study, we evaluated the protective effect of mangiferin on osteoarthritis (OA) in vitro and in vivo. First, the effect of different concentrations of mangiferin on rat chondrocytes was determined by MTT assay. Second, the effects of mangiferin on the expression levels of matrix metalloproteinase (MMP)-13, TNF alpha, Collagen II, Caspase-3, and cystatin-C in interleukin-1beta (IL-1beta)-induced rat chondrocytes were examined by the real-time polymerase chain reaction in vitro, meanwhile the effects of mangiferin on the nuclear factor kappa-B (NF-kappaB) signaling pathway were also investigated by Western Blot. Finally, the anti-osteoarthritic protective effect of mangiferin was evaluated in the rat model by anterior cruciate ligament transection (ACLT) combined with bilateral ovariectomy-induced OA in vivo. The results showed that the mangiferin was found to inhibit the expression of MMP-13, TNF-alpha, and Caspase-3 which also increased the expression of Collagen II and cystatin-C in IL 1beta induced rat chondrocytes. In addition, IL-1beta-induced activation of nuclear factor kappa-B (NF-kappaB) and the degradation of inhibitor of kappaB (IkappaB)-alpha were suppressed by mangiferin. For the in vivo study in a rat model of OA, 100 microl of mangiferin was administered by intra-articular injections for rats, the results showed that the cartilage degradation was suppressed by mangiferin through Micro CT and Histological Examination. According to both in vitro and in vivo results, mangiferin has a protective effect in the treatment of OA which may be a promising therapeutic agent for OA.

Polymorphism of MMP-3 gene and imbalance expression of MMP-3 / TIMP-1 in articular cartilage are associated with an endemic osteochondropathy, Kashin- Beck disease

Background

The etiology of Kashin-Beck disease (KBD), an endemic osteochondropathy, is largely unknown. Matrix metalloproteinase-3 (MMP-3) plays a central role in the initiation and progression of cartilage destruction, however, no study has reported on the relationship between KBD and MMP-3. The objective of this study was to explore the polymorphism of MMP-3 gene and expression of MMP-3 / TIMP-1(Tissue inhibitors of matrixmetalloproteinases-1) in the pathogenesis of KBD.

Methods

Single nucleotide polymorphism (SNP) genotyping was conducted in 274 KBD cases and 248 healthy controls for eight SNPs in MMP-3 using the Sequenom MassARRAY system. Additionally, the expression of MMP-3、TIMP-1 in different layers of the articular cartilage was analyzed by immunohistochemistry for 22 KBD patients, 15 osteoarthritis (OA) patients and 21 controls.

Results

The results showed that six SNPs (rs520540、rs591058、rs679620、rs602128、rs639752 and rs678815) in MMP-3 were associated with the increased risk of KBD, however, after Bonferroni correction, only the SNP rs679620 in the recessive model remained significant difference (OR = 2.31, 95%CI = 1.29–4.14, P = 0.0039), homozygous for “T” allele have a risk for KBD than “C” allele carriers. Moreover, the percentages of cells expressing MMP-3 in articular cartilage were significantly higher in the KBD and OA groups than in the controls (t = 5.37 and 4.19, P<0.01). While the KBD and OA groups had lower levels of TIMP-1 positive staining compared with the controls (t = 5.23and 5.06, P<0.01). And there was no significant different between KBD and OA for the levels of MMP-3 and TIMP-1 positive staining (t = 0.05and 0.28, P>0.05).

Conclusions

MMP-3 is associated with the susceptibility of KBD, and the imbalance expression of MMPs / TIMPs leading to cartilage degradation may play an important role in cartilage degradation and osteoarthritis formation in OA and KBD.

Effects of Exercise Training Alone and in Combination With Kinesio Taping on Pain, Functionality, and Biomarkers Related to the Cartilage Metabolism in Knee Osteoarthritis

OBJECTIVE

To investigate the effects of exercise training alone and in combination with kinesio taping on pain, functionality, and circulating cartilage oligomeric matrix protein (COMP), and matrix metalloproteinase (MMP)-1, and -3 at rest and immediately after walking exercise in knee osteoarthritis (OA).

DESIGN

A total of 22 female patients diagnosed with knee OA were randomly divided into the exercise training (ET) or exercise training plus kinesio taping (ET + KT) groups. The patients in the ET performed exercise training for 6 weeks. The patients in the ET + KT group were applied with kinesio tape in addition to the exercise training for 6 weeks. In both groups, 20 minutes of walking exercise were performed before and after the interventions. The pain and functional status of the patients were assessed using visual analogue scale (VAS) and Western Ontario McMasters Osteoarthritis Index (WOMAC) before and after the intervention at rest, respectively. Blood samples were taken at rest and immediately after the walking exercise before and after the interventions for the analysis of COMP, MMP-1, and MMP-3 levels.

RESULTS

In both groups, pain and functionality scores were significantly improved after the interventions (P < 0.05). COMP, MMP-1 and MMP-3 levels were higher immediately after walking exercise when compared with rest in both groups before and after the intervention (P < 0.05).

CONCLUSIONS

Exercise training and exercise training plus kinesio taping improved pain and physical function; however, the COMP, MMP-1, and MMP-3 levels did not change.

Vicenin 3 ameliorates ECM degradation by regulating the MAPK pathway in SW1353 chondrocytes

Aberrant destruction of the articular extracellular matrix (ECM) has been considered to be one of the pathological features of osteoarthritis (OA) which results in chondrocyte changes and articular cartilage degeneration. The MAPK signaling pathway serves a key role by releasing cartilage-degrading enzymes from OA chondrocytes. However, the use of MAPK inhibitors for OA is hindered by their potential long-term toxicity. Vicenin 3 is one of the major components of the Jian-Gu injection which is effective in the clinical treatment of OA. However, its potential impact on OA remain poorly understood. Therefore, the present study aimed to assess the effects of vicenin 3 on interleukin (IL)-1β-treated SW1353 chondrocytes, which mimic the microenvironment of OA. These chondrocytes were pretreated with vicenin 3 (0, 5 and 20 µM) for 1 h and subsequently stimulated with IL-1β (10 ng/ml) for 24 h. Nitric oxide (NO) production was measured using the Griess reaction, whereas the production of prostaglandin E2 (PGE2), matrix metalloproteinases (MMPs), A disintegrin-like and metalloproteinase with thrombospondin motifs (ADAMTSs), collagen type II and aggrecan were measured using ELISA. The mRNA expression of MMPs and ADAMTSs were measured using reverse transcription-quantitative PCR. The protein expression levels of MAPK were measured using western blotting. Vicenin 3 was found to significantly inhibit IL-1β-induced production of NO and PGE. Increments in the expression levels of MMP-1, MMP-3, MMP-13, ADAMTS-4 and ADAMTS-5 induced by IL-1β, in addition to the IL-1β-induced degradation of collagen type II and aggrecan, were all reversed by vicenin 3 treatment. Furthermore, vicenin 3 suppressed IL-1β-stimulated MAPK activation, an effect that was similar to that exerted by SB203580, a well-known p38 MAPK inhibitor. In conclusion, vicenin 3 may confer therapeutic potential similar to that of the p38 MAPK inhibitor for the treatment of OA.

Indole Inhibitors of MMP-13 for Arthritic Disorders

Here, we described the design, by fragment merging and multiparameter optimization, of selective MMP-13 inhibitors that display an appropriate balance of potency and physicochemical properties to qualify as tool compounds suitable for in vivo testing. Optimization of potency was guided by structure-based insights, specifically to replace an ester moiety and introduce polar directional hydrogen bonding interactions in the core of the molecule. By introducing polar enthalpic interactions in this series of inhibitors, the overall beneficial physicochemical properties were maintained. These physicochemical properties translated to excellent drug-like properties beyond potency. In a murine model of rheumatoid arthritis, treatment of mice with selective inhibitors of MMP-13 resulted in a statistically significant reduction in the mean arthritic score vs control when dosed over a 14 day period.

Gene Expression Profiles Analyzed Using Integrating RNA Sequencing, and Microarray Reveals Increased Inflammatory Response, Proliferation, and Osteoclastogenesis in Pigmented Villonodular Synovitis

Background

Pigmented villonodular synovitis (PVNS) is a rare condition that involves benign proliferation of the synovial tissue and is characterized by severe joint destruction and high recurrence even after surgical resection. However, poor understanding of the pathogenesis limits its effective therapy.

Method

In this study, gene expression profiles of six patients with PVNS, 11 patients with osteoarthritis (OA), nine patients with rheumatoid arthritis (RA) (E-MTAB-6141), and three healthy subjects (GSE143514) were analyzed using integrating RNA sequencing (RNA-seq) and microarray to investigate the PVNS transcriptome. Gene ontology, string, and cytoscape were used to determine the gene functional enrichment. Cell functional molecules were detected using flow cytometry or immunohistochemical test to identify the cell subset and function. CD14⁺ cells were isolated and induced to osteoclast to evaluate the monocyte/macrophage function.

Results

The most obvious local manifestations of PVNS were inflammation, including increased immune cells infiltration and cytokine secretion, and tumor phenotypes. High proportion of inflammatory cells, including T cells, natural killer (NK) cells, NKT cells, and B cells were recruited from the blood. Th17 and monocytes, especially classical monocytes but not nonclassical monocytes, increased in PVNS synovium. An obvious increase in osteoclastogenesis and macrophage activation was observed locally. Elevated expression of MMP9, SIGLEC 15, and RANK were observed in myeloid cell of PVNS than OA. When compared with RA, osteoclast differentiation and myeloid cell activation are PVNS-specific characters, whereas T cell activation is shared by PVNS and RA.

Conclusion

The transcriptional expression characteristics of PVNS showed increased immune response, cell migration, and osteoclastogenesis. Osteoclast differentiation is only observed in PVNS but not RA, whereas T-cell activation is common in inflammatory arthritis.

Proteomic Analysis of Synovial Fibroblasts and Articular Chondrocytes Co-Cultures Reveals Valuable VIP-Modulated Inflammatory and Degradative Proteins in Osteoarthritis

Osteoarthritis (OA) is the most common musculoskeletal disorder causing a great disability and a reduction in the quality of life. In OA, articular chondrocytes (AC) and synovial fibroblasts (SF) release innate-derived immune mediators that initiate and perpetuate inflammation, inducing cartilage extracellular matrix (ECM) degradation. Given the lack of therapies for the treatment of OA, in this study, we explore biomarkers that enable the development of new therapeutical approaches. We analyze the set of secreted proteins in AC and SF co-cultures by stable isotope labeling with amino acids (SILAC). We describe, for the first time, 115 proteins detected in SF-AC co-cultures stimulated by fibronectin fragments (Fn-fs). We also study the role of the vasoactive intestinal peptide (VIP) in this secretome, providing new proteins involved in the main events of OA, confirmed by ELISA and multiplex analyses. VIP decreases proteins involved in the inflammatory process (CHI3L1, PTX3), complement activation (C1r, C3), and cartilage ECM degradation (DCN, CTSB and MMP2), key events in the initiation and progression of OA. Our results support the anti-inflammatory and anti-catabolic properties of VIP in rheumatic diseases and provide potential new targets for OA treatment.

Ferulic acid suppresses interleukin-1β-induced degeneration of chondrocytes isolated from patients with osteoarthritis through the SIRT1/AMPK/PGC-1α signaling pathway

Background

Interleukin‐1β (IL‐1β) is involved in osteoarthritis pathogenesis and mediates a series of toxic processes including the production of matrix metalloproteinase and inflammatory regulators which are suppressed by activation of silent information regulator 1 (SIRT1). We aimed to determine the effects of ferulic acid (FA) on IL‐1β‐induced osteoarthritis chondrocyte degeneration.

Methods

We examined the effects of FA on osteoarthritis chondrocyte viability and SIRT1 activation. The impact of FA on IL‐1β‐induced osteoarthritis chondrocyte toxicity was determined by prostaglandin E2 (PGE₂), nitrite, IL‐6, components of the extracellular matrix, and markers of oxidative stress. Finally, we determined whether these effects were mediated through SIRT1 by inhibiting SIRT1 activity using SIRT1 inhibitor Sirtinol.

Results

We found that FA activated SIRT1/AMPK/PGC‐1α signaling pathway and attenuated IL‐1β‐induced osteoarthritis chondrocyte degeneration by suppressing the production of IL‐6, PGE₂, nitrite, Collagen I, Runx‐2, MMP‐1, MMP‐3, and MMP‐13, enhancing Collagen II and Aggrecan expression and inhibiting oxidative stress. Inhibition of SIRT1 by Sirtinol attenuated the protective effects of FA.

Conclusion

Our findings reveal that FA prevents IL‐1β‐induced osteoarthritis chondrocyte toxicity, which suggests that FA may be a potential therapy for osteoarthritis and warrants further investigation for its clinical application.

Excessive downhill training leads to early onset of knee osteoarthritis

OBJECTIVE

Increased levels of pro-inflammatory cytokines are associated with the release of degradative enzymes leading to osteoarthritis (OA) development. Although physical exercise (PE) is generally recognized as beneficial for OA symptoms, excessive training workload and eccentric muscular exercise have increased OA risk. Here, we investigated the effects of excessive exercise workload and exercise type on systemic inflammation and knee joint OA.

METHODS

Mice were divided into five groups: sedentary (SED), uphill training (TRU), downhill training (TRD), excessive uphill training (ETU), and excessive downhill training (ETD) for an 8-week training intervention protocol.

RESULTS

ETD group had increased pro-inflammatory cytokines in serum, vastus lateralis (VL), and vastus medialis (VM) muscles, while ETU group mice had increased cytokine levels in the VL and VM. Total knee joint OARSI score were more significant in ETD group compared to SED and TRU groups. They were also more meaningful for the medial tibial plateau of ETD group compared to SED group. MMP-3 and cleaved Caspase-3 were higher in the ETD group than the SED and TRU group, while Adamts-5 was higher in the ETD group than the SED group. TRU group had increased PRG-4 levels compared to ETU and ETD group. ETD group had decreased total bone volume, trabecular bone volume, and cortical thickness compared to SED group.

CONCLUSION

Excessive downhill training induced a chronic pro-inflammatory state in mice and was associated with early signs of cartilage and bone degeneration that are clinical indicators of knee OA.

Identification of Candidate Synovial Fluid Biomarkers for the Prediction of Patient Outcome After Microfracture or Osteotomy

BACKGROUND

Biomarkers are needed to predict clinical outcomes for microfracture and osteotomy surgeries to ensure patients can be better stratified to receive the most appropriate treatment.

PURPOSE

To identify novel biomarker candidates and to investigate the potential of a panel of protein biomarkers for the prediction of clinical outcome after treatment with microfracture or osteotomy.

STUDY DESIGN

Descriptive laboratory study.

METHODS

To identify novel candidate biomarker proteins, we used label-free quantitation after liquid chromatography-tandem mass spectrometry of dynamic range-compressed synovial fluids (SFs) from individuals who responded excellently or poorly (based on change in Lysholm score) to microfracture (n = 6) or osteotomy (n = 7). Biomarkers that were identified in this proteomic analysis or that relate to osteoarthritis (OA) severity or have predictive value in another early OA therapy (autologous cell implantation) were measured in the SF of 19 and 13 patients before microfracture or osteotomy, respectively, using commercial immunoassays, and were normalized to urea. These were aggrecanase-1 (ADAMTS-4), cartilage oligomeric matrix protein (COMP), hyaluronan (HA), lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1), matrix metalloproteinase 1 and 3, soluble CD14, S100 calcium binding protein A13, and 14-3-3 protein theta (YWHAQ). Levels of COMP and HA were also measured in the plasma of these patients. To find predictors of postoperative function, multivariable regression analyses were performed.

RESULTS

Proteomic analyses highlighted YWHAQ and LYVE-1 as being differentially abundant between the clinical responders/improvers and nonresponders after microfracture. A linear regression model after backward variable selection could relate preoperative concentrations of SF proteins (HA, YWHAQ, LYVE-1), activity of ADAMTS-4, and patient demographic characteristics (smoker status and sex) with Lysholm score 12 months after microfracture. Further, a generalized linear model with elastic net penalization indicated that lower preoperative activity of ADAMTS-4 in SF, being a nonsmoker, and being younger at the time of operation were indicative of a higher postoperative Lysholm score (improved joint function) after osteotomy surgery.

CONCLUSION

We have identified biomarkers and generated regression models with the potential to predict clinical outcome in patients treated with microfracture or osteotomy of the knee.

CLINICAL RELEVANCE

Candidate protein biomarkers identified in this study have the potential to help determine which patients will be best suited to treatment with microfracture or osteotomy.

Nanomedicines for the treatment of rheumatoid arthritis: State of art and potential therapeutic strategies

Increasing understanding of the pathogenesis of rheumatoid arthritis (RA) has remarkably promoted the development of effective therapeutic regimens of RA. Nevertheless, the inadequate response to current therapies in a proportion of patients, the systemic toxicity accompanied by long-term administration or distribution in non-targeted sites and the comprised efficacy caused by undesirable bioavailability, are still unsettled problems lying across the full remission of RA. So far, these existing limitations have inspired comprehensive academic researches on nanomedicines for RA treatment. A variety of versatile nanocarriers with controllable physicochemical properties, tailorable drug release pattern or active targeting ability were fabricated to enhance the drug delivery efficiency in RA treatment. This review aims to provide an up-to-date progress regarding to RA treatment using nanomedicines in the last 5 years and concisely discuss the potential application of several newly emerged therapeutic strategies such as inducing the antigen-specific tolerance, pro-resolving therapy or regulating the immunometabolism for RA treatments.

3'-Sialyllactose Protects SW1353 Chondrocytic Cells From Interleukin-1β-Induced Oxidative Stress and Inflammation

Osteoarthritis (OA) is a major degenerative joint disease. Oxidative stress and inflammation play key roles in the pathogenesis of OA. 3'-Sialyllactose (3'-SL) is derived from human milk and is known to regulate a variety of biological functions related to immune homeostasis. This study aimed to investigate the therapeutic mechanisms of 3'-SL in interleukin-1β (IL-1β)-treated SW1353 chondrocytic cells. 3'-SL potently suppressed IL-1β-induced oxidative stress by increasing the levels of enzymatic antioxidants. 3'-SL significantly reversed the IL-1β mediated expression levels of reactive oxygen species in IL-1β-stimulated chondrocytic cells. In addition, 3'-SL could reverse the increased levels of inflammatory markers such as nitrite, prostaglandin E2, inducible nitric oxide synthase, cyclooxygenase-2, IL-1β, and IL-6 in IL-1β-stimulated chondrocytic cells. Moreover, 3'-SL significantly inhibited the apoptotic process, as indicated by the downregulation of the pro-apoptotic protein Bax, upregulation of the anti-apoptotic protein Bcl-2 expression, and significant reduction in the number of TUNEL-positive cells in the IL-1β-treated chondrocytic cells. Furthermore, 3'-SL reversed cartilage destruction by decreasing the release of matrix metalloproteinases (MMP), such as MMP1, MMP3, and MMP13. In contrast, 3'-SL significantly increased the expression levels of matrix synthesis proteins, such as collagen II and aggrecan, in IL-1β-treated chondrocytic cells. 3'-SL dramatically suppressed the activation of mitogen-activated protein kinases (MAPK) and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathways, which are related to the pathogenesis of OA. Taken together, our data suggest that 3'-SL alleviates IL-1β-induced OA pathogenesis via inhibition of activated MAPK and PI3K/AKT/NF-κB signaling cascades with the downregulation of oxidative stress and inflammation. Therefore, 3'-SL has the potential to be used as a natural compound for OA therapy owing to its ability to activate the antioxidant defense system and suppress inflammatory responses.

Kaempferia parviflora Extract Alleviated Rat Arthritis, Exerted Chondroprotective Properties In Vitro, and Reduced Expression of Genes Associated with Inflammatory Arthritis

Kaempferia parviflora Wall. ex Baker (KP) has been reported to attenuate cartilage destruction in rat model of osteoarthritis. Previously, we demonstrated that KP rhizome extract and its active components effectively suppressed mechanisms associated with RA in SW982 cells. Here, we further evaluated the anti-arthritis potential of KP extract by using multi-level models, including a complete Freund’s adjuvant-induced arthritis and a cartilage explant culture model, and to investigate the effects of KP extract and its major components on related gene expressions and underlying mechanisms within cells. In arthritis rats, the KP extract reduced arthritis indexes, with no significant changes in biological parameters. In the cartilage explant model, the KP extract exerted chondroprotective potential by suppressing sulfated glycosaminoglycans release while preserving high accumulation of proteoglycans. In human chondrocyte cell line, a mixture of the major components equal to their amounts in KP extract showed strong suppression the expression of genes-associated inflammatory joint disease similar to that of the extract. Additionally, KP extract significantly suppressed NF-κB and MAPK signaling pathways. The suppressing expression of necroptosis genes and promoted anti-apoptosis were also found. Collectively, these results provided supportive evidence of the anti-arthritis properties of KP extract, which are associated with its three major components.

Alterations of Extracellular Matrix Components in the Course of Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) is the most common group of chronic connective tissue diseases in children that is accompanied by joint structure and function disorders. Inflammation underlying the pathogenic changes in JIA, caused by hypersecretion of proinflammatory cytokines, leads to the destruction of articular cartilage. The degradation which progresses with the duration of JIA is not compensated by the extent of repair processes. These disorders are attributed in particular to changes in homeostasis of extracellular matrix (ECM) components, including proteoglycans, that forms articular cartilage. Changes in metabolism of matrix components, associated with the disturbance of their degradation and biosynthesis processes, are the basis of the progressive wear of joint structures observed in the course of JIA. Clinical evaluation and radiographic imaging are current methods to identify the destruction. The aim of this paper is to review enzymatic and non-enzymatic factors involved in catabolism of matrix components and molecules stimulating their biosynthesis. Therefore, we discuss the changes in these factors in body fluids of children with JIA and their potential diagnostic use in the assessment of disease activity. Understanding the changes in ECM components in the course of the child-hood arthritis may provide the introduction of both new diagnostic tools and new therapeutic strategies in children with JIA.

Transcriptional response of human articular chondrocytes treated with fibronectin fragments: an in vitro model of the osteoarthritis phenotype

OBJECTIVE

Fibronectin is a matrix protein that is fragmented during cartilage degradation in osteoarthritis (OA). Treatment of chondrocytes with fibronectin fragments (FN-f) has been used to model OA in vitro, but the system has not been fully characterized. This study sought to define the transcriptional response of chondrocytes to FN-f, and directly compare it to responses traditionally observed in OA.

DESIGN

Normal human femoral chondrocytes isolated from tissue donors were treated with either FN-f or PBS (control) for 3, 6, or 18 h. RNA-seq libraries were compared between time-matched FN-f and control samples in order to identify changes in gene expression over time. Differentially expressed genes were compared to a published OA gene set and used for pathway, transcription factor motif, and kinome analysis.

RESULTS

FN-f treatment resulted in 3,914 differentially expressed genes over the time course. Genes that are up- or downregulated in OA were significantly up- (P < 0.00001) or downregulated (P < 0.0004) in response to FN-f. Early response genes were involved in proinflammatory pathways, whereas many late response genes were involved in ferroptosis. The promoters of upregulated genes were enriched for NF-κB, AP-1, and IRF motifs. Highly upregulated kinases included CAMK1G, IRAK2, and the uncharacterized kinase DYRK3, while growth factor receptors TGFBR2 and FGFR2 were downregulated.

CONCLUSIONS

FN-f treatment of normal human articular chondrocytes recapitulated many key aspects of the OA chondrocyte phenotype. This in vitro model is promising for future OA studies, especially considering its compatibility with genomics and genome-editing techniques.

High expression of MAPK-14 promoting the death of chondrocytes is an important signal of osteoarthritis process

Background

Osteoarthritis (OA) is one of the most common degenerative diseases worldwide. Many researchers are studying the pathogenesis of OA, however, it is still unclear.

Methods

Screening and validation of OA relevant hub genes are an important part of exploring their potential molecular mechanism. Therefore, this study aims to explore and verify the mechanisms of hub genes in the OA by bioinformatics, qPCR, fluorescence and propidium iodide staining.

Results

Microarray datasets GSE43923, GSE55457 and GSE12021 were collected in the Gene Expression Omnibus (GEO), including 45 samples, which divided into 23 osteoarthritis knee joint samples and 22 samples of normal knee joint. Thereafter, 265 differentiallyexpressedgenes (DEGs) were identified in all, which divided into 199 upregulated genes and 66 downregulated genes. The hub genes MAPK-14, PTPRC, PTPN12 were upregulated, while B9D1 was downregulated. In order to further confirm the expression of screening differential genes in human chondrocytes, the human chondrocytes were extracted from a joint replacement surgery and stained with toluidine blue for identification. Compared with normal chondrocytes, OA chondrocytes had high expression of COL I protein and low expression of COL II protein. The expression levels of MAPK-14, PTPRC and PTPN12 in OA chondrocytes were significantly higher than the expression levels of B9D1 in normal chondrocytes. Moreover, the inflammatory necrosis of OA chondrocytes was increased compared with the normal chondrocytes by propidium iodide staining.

Conclusions

The high expression of MAPK-14 works as a promoter of chondrocytes death and an important signal of the osteoarthritis process.

Network Pharmacology Approach to Uncover the Mechanism Governing the Effect of Simiao Powder on Knee Osteoarthritis

Objective

To explore the molecular mechanism of Simiao powder in the treatment of knee osteoarthritis.

Methods

Based on oral bioavailability and drug-likeness, the main active components of Simiao powder were screened using the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). GeneCard, OMIM, DisGeNET, DrugBank, PharmGkb, and the Therapeutic Target Database were used to establish target databases for knee osteoarthritis. Cytoscape software was used to construct a visual interactive network diagram of “active ingredient - action target – disease.” The STRING database was used to construct a protein interaction network and analyze related protein interaction relationships. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) biological process enrichment analysis were performed on the core targets. Additionally, Discovery Studio software was used for molecular docking verification of active pharmaceutical ingredients and disease targets.

Results

Thirty-seven active components of Simiao powder were screened, including 106 common targets. The results of network analysis showed that the targets were mainly involved in regulating biological processes such as cell metabolism and apoptosis. Simiao powder components were predicted to exert their therapeutic effect on the AGE-RAGE signaling pathway in diabetic complications, IL-17 signaling pathway, TNF signaling pathway, Toll-like receptor signaling pathway, and HIF-1 signaling pathway. The molecular docking results showed that the active components of Simiao powder had a good match with the targets of IL1B, MMP9, CXCL8, MAPK8, JUN, IL6, MAPK1, EGF, VEGFA, AKT1, and PTGS2.

Conclusion

Simiao powder has multisystem, multicomponent, and multitarget characteristics in treating knee osteoarthritis. Its possible mechanism of action includes inhibiting the inflammatory response, regulating immune function, and resisting oxidative stress to control the occurrence and development of the disease. Quercetin, wogonin, kaempferol, beta-sitosterol, and other active ingredients may be the material basis for the treatment of knee osteoarthritis.

A Complete and Versatile Protocol: Decoration of Cell-Derived Matrices with Mass-Encoded Peptides for Multiplexed Protease Activity Detection

This article provides guidance toward a platform technology for monitoring enzyme activity within the extracellular matrix (ECM) assessed by quantifying reporters secreted into the cell culture supernatant and analyzed by tandem mass spectrometry. The reporters are enzymatically and covalently bound to the ECM by transglutaminases (TG) using the peptide sequence of human insulin-like growth factor I's (IGF-I) D-domain which is known to be bound to the ECM by transglutaminase. The IGF-I D-domain sequence is followed by a peptide sequence cleaved by the intended target protease. This protease-sensitive peptide sequence (PSS) is cleaved off the ECM and can be used to monitor target-enzyme activity by employing a downstream mass tag designed according to isobaric mass encoding strategies, i.e., the combination of isotopically labeled, heavy amino acids. Thereby, cleavage events are linked to the appearance of encoded mass tags, readily allowing multiplexing. This article presents the design and synthesis of these mass reporters. It further aims at detailing the search for peptide sequences responding to target proteases to facilitate future work on enzyme activity measurement for enzymatic activities of hitherto unknown enzymes. In conclusion, the goal of this article is to arm scientists interested in measurements of local enzymatic activities within the ECM with robust protocols and background knowledge.

Challenges with matrix metalloproteinase inhibition and future drug discovery avenues

INTRODUCTION

Matrix metalloproteinases have been in the scope of pharmaceutical drug discovery for decades as promising targets for drug development. Until present, no modulator of the enzyme class survived clinical trials, all failing for various reasons. Nevertheless, the target family did not lose its attractiveness and there is ever more evidence that MMP modulators are likely to overcome the hurdles and result in successful clinical therapies.

AREAS COVERED

This review provides an overview of past efforts that were taken in the development of MMP inhibitors and insight into promising strategies that might enable drug discovery in the field in the future. Small molecule inhibitors as well as biomolecules are reviewed.

EXPERT OPINION

Despite the lack of successful clinical trials in the past, there is ongoing research in the field of MMP modulation, proving the target class has not lost its appeal to pharmaceutical research. With ever-growing insights from different scientific fields that shed light on previously unknown correlations, it is now time to use synergies deriving from biological knowledge, chemical structure generation, and clinical application to reach the ultimate goal of bringing MMP derived drugs on a broad front for the benefit of patients into therapeutic use.

Mass-Encoded Reporters Reporting Proteolytic Activity from within the Extracellular Matrix

Reporting matrix metalloproteinase (MMP) activity directly from the extracellular matrix (ECM) may provide critical insights to better characterize 2D and 3D cell culture model systems of inflammatory diseases and potentially leverage in vivo diagnosis. In this proof-of-concept study, we designed MMP-sensors, which were covalently linked onto the ECM by co-administration of the activated transglutaminase factor XIIIa (FXIIIa). Elements of the featured MMP-sensors are the D-domain of insulin-like growth factor I (IGF-I) through which co-administered FXIIIa covalently links the sensor to the ECM followed by an MMP sensitive peptide sequence and locally reporting on MMP activity, an isotopically labeled mass tag encoding for protease activity, and an affinity tag facilitating purification from fluids. All sensors come in identical pairs, other than the MMP sensitive peptide sequence, which is synthesized with l-amino acids or d-amino acids, the latter serving as internal standard. As a proof of concept for multiplexing, we successfully profiled two MMP-sensors with different MMP sensitive peptide sequences reporting MMP activity directly from an engineered 3D ECM. Future use may include covalently ECM bound diagnostic depots reporting MMP activity from inflamed tissues.

Genetics in Cartilage Lesions: Basic Science and Therapy Approaches

Cartilage lesions have a multifactorial nature, and genetic factors are their strongest determinants. As biochemical and genetic studies have dramatically progressed over the past decade, the molecular basis of cartilage pathologies has become clearer. Several homeostasis abnormalities within cartilaginous tissue have been found, including various structural changes, differential gene expression patterns, as well as altered epigenetic regulation. However, the efficient treatment of cartilage pathologies represents a substantial challenge. Understanding the complex genetic background pertaining to cartilage pathologies is useful primarily in the context of seeking new pathways leading to disease progression as well as in developing new targeted therapies. A technology utilizing gene transfer to deliver therapeutic genes to the site of injury is quickly becoming an emerging approach in cartilage renewal. The goal of this work is to provide an overview of the genetic basis of chondral lesions and the different approaches of the most recent systems exploiting therapeutic gene transfer in cartilage repair. The integration of tissue engineering with viral gene vectors is a novel and active area of research. However, despite promising preclinical data, this therapeutic concept needs to be supported by the growing body of clinical trials.

Histopathological Signatures of the Femoral Head in Patients with Osteonecrosis and Potential Applications in a Multi-Targeted Approach: A Pilot Study

(1) Background: Osteonecrosis (ON) of the femoral head is a disabling disease for which limited treatment options exist. Identifying therapeutic targets of its evolution could provide crucial insights into multi-targeted approaches. The aim of this pilot study was to assess the histopathological features of patients with non-traumatic femoral head (NTFH) and post-traumatic femoral head (PTFH) ON to produce a fresh vision for clinical use. (2) Methods: We got biopsies from patients with different ON stages, according to the ARCO system. Samples from multi-organ donors were used as controls. Histological and immunohistochemical evaluations were performed on the osteochondral unit. (3) Results: The PTFH group displayed several fibrotic reactions, a small stem cell pool and a lower international cartilage repair society (ICRS)-I score than NTFH, which instead presented intact cartilage similar to the controls. Immunostaining for collagen I and autotaxin confirmed these features in the PTFH group, which displayed top levels of MMP-13 involved in cartilage loss and reduced CB-2 in the underlying bone. Both groups manifested a similar pattern of apoptotic and pain mediators. (4) Conclusions: The different histopathological features suggest a multi-disciplinary and multi-targeted approach for ON. Further studies are necessary to measure the effect size to gain clinical evidence.

A novel indomethacin/methotrexate/MMP-9 siRNA in situ hydrogel with dual effects of anti-inflammatory activity and reversal of cartilage disruption for the synergistic treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammatory cell infiltration, and cartilage and bone disruption, which ultimately leads to loss of joint function. Current treatments for RA only focus on anti-inflammatory activity but neglect to prevent further damage to articular cartilage and bone. Here we attempted to co-deliver indomethacin (IND), methotrexate (MTX) and a small-interfering RNA targeting MMP-9 using an in situ hydrogel loaded with PEI-SS-IND-MTX-MMP-9 siRNA nanoparticles (D/siRNA-NGel) to treat RA synergistically and comprehensively. IND, MTX and MMP-9 siRNA were able to escape from the endosome and down-regulate the expression of MMP-9 and inflammatory cytokines of Raw-264.7 cells. After intra-articular injection in arthritic mice, the D/siRNA-NGel effectively relieved joint swelling and significantly reduced the expression of TNF-α, IL-6 and MMP-9 in the ankle fluid, knee joint fluid and plasma of RA mice without causing any side effects. Most importantly, the co-delivery system restored the morphological parameters of the ankle joints close to normal. The D/siRNA-NGel could achieve good anti-inflammatory activity and reverse cartilage disruption through a synergistic effect between chemical drugs and MMP-9 siRNA. This co-delivery system should have promising applications in the treatment of rheumatoid arthritis and other metabolic bone diseases which cause serious bone erosion.

Integrated Transcriptomic and Proteomic Analyses of the Interaction Between Chicken Synovial Fibroblasts and Mycoplasma synoviae

Mycoplasma synoviae (MS), which causes respiratory disease, eggshell apex abnormalities, infectious synovitis, and arthritis in avian species, has become an economically detrimental poultry pathogen in recent years. In China, the disease is characterized by infectious synovitis and arthritis. However, the mechanism by which MS causes infectious synovitis and arthritis remains unknown. Increasing evidence suggests that synovial fibroblasts (SF) play a key role in the pathogenesis of arthritis. Here, both RNA sequencing and tandem mass tag analyses are utilized to compare the response of primary chicken SF (CSF) following infection with and without MS. The host response between non-infected and infected cells was remarkably different at both the mRNA and protein levels. In total, 2,347 differentially expressed genes (DEGs) (upregulated, n = 1,137; downregulated, n = 1,210) and 221 differentially expressed proteins (DEPs) (upregulated, n = 129; downregulated, n = 92) were detected in the infected group. A correlation analysis indicated a moderate positive correlation between the mRNA and protein level changes in MS-infected CSF. At both the transcriptomic and proteomic levels, 149 DEGs were identified; 88 genes were upregulated and 61 genes were downregulated in CSF. Additionally, part of these regulated genes and their protein products were grouped into seven categories: proliferation-related and apoptosis-related factors, inflammatory mediators, proangiogenic factors, antiangiogenic factors, matrix metalloproteinases, and other arthritis-related proteins. These proteins may be involved in the pathogenesis of MS-induced arthritis in chickens. To our knowledge, this is the first integrated analysis on the mechanism of CSF-MS interactions that combined transcriptomic and proteomic technologies. In this study, many key candidate genes and their protein products related to MS-induced infectious synovitis and arthritis were identified.

Resistance training decreases matrix metalloproteinase-2 activity in quadriceps tendon in a rat model of osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a degenerative disease that induces peri-articular tissue degradation. OA induces an imbalance between synthesis and degradation of the extracellular matrix components in favor of catabolic events, promoting pathological remodeling and involving degradative enzymes, such as matrix metalloproteinases (MMPs).

OBJECTIVE

This study aimed to investigate the effects of 8-weeks resistance training (RT) on MMP-2 activity in the quadriceps tendon and patellar tendon in an OA model.

METHODS

Twenty-four Wistar rats were randomly divided into six groups: Control, Exercise, Sham, Sham with Exercise, OA, and OA with Exercise (OAE). The OA model was performed by anterior cruciate ligament transection surgery on the left knee. The 8-week RT consisted of climbing a 1.1-m vertical ladder three times per week with progressive weights secured to the animals' tails. MMP-2 activity was analyzed by zymography.

RESULTS

The OAE group displayed lower pro, intermediate, and active MMP-2 activity in the quadriceps tendon compared with the OA group (p<0.05). For the patellar tendon, there was no significant difference between the OAE group compared with the other groups (p>0.05) for pro, intermediate, and active MMP-2 activity. Moreover, MMP-2 activity differed between tissues, the OA and OAE groups presented lower pro, intermediate, and active MMP-2 activity in the quadriceps tendon compared to the patellar tendon.

CONCLUSION

RT induced down-regulated MMP-2 activity in the quadriceps tendon. RT is a potential therapeutic approach to minimize the deleterious effects of extracellular matrix degeneration.

Common innate pathways to autoimmune disease

Until recently, autoimmune disease research has primarily been focused on elucidating the role of the adaptive immune system. In the past decade or so, the role of the innate immune system in the pathogenesis of autoimmunity has increasingly been realized. Recent findings have elucidated paradigm-shifting concepts, for example, the implications of "trained immunity" and a dysbiotic microbiome in the susceptibility of predisposed individuals to clinical autoimmunity. In addition, the application of modern technologies such as the quantum dot (Qdot) system and 'Omics' (e.g., genomics, proteomics, and metabolomics) data-processing tools has proven fruitful in revisiting mechanisms underlying autoimmune pathogenesis and in identifying novel therapeutic targets. This review highlights recent findings discussed at the American Autoimmune Related Disease Association (AARDA) 2019 colloquium. The findings covering autoimmune diseases and autoinflammatory diseases illustrate how new developments in common innate immune pathways can contribute to the better understanding and management of these immune-mediated disorders.

NF-κB Phosphorylation Inhibition Prevents Articular Cartilage Degradation in Osteoarthritis Rats via 2-Aminoquinoline

Background

Osteoarthritis is a chronic degenerative disease of the joints that is common in older people worldwide. The characteristic features of osteoarthritis include cartilage degradation, synovitis, and remodelling of subchondral bone. The present study investigated the effect of 2-aminoquinoline on knee articular cartilage degradation in an osteoarthritis rat model.

Material/Methods

The rat model of osteoarthritis was established in Wistar rats by intra-articular injection of monosodium iodoacetate. The rats were randomly divided into 6 groups of 10 rats each: a normal control group, an untreated group, and 4 (5, 10, 15 and 20 mg/kg) treatment groups. The rats in treatment groups received 5, 10, 15, or 20 mg/kg doses of 2-aminoquinoline on day 2 of monosodium iodoacetate injection.

Results

The 2-aminoquinoline treatment of monosodium iodoacetate-injected rats markedly decreased weight-bearing asymmetry, inhibited edema formation, and improved paw withdrawal thresholds. The expression of inflammatory cytokines was markedly higher in the osteoarthritis rats. Treatment with 2-aminoquinoline led to a significant reduction in inflammatory cytokine expression in osteoarthritis rats in a dose-dependent manner. In osteoarthritis rats, the expressions of prostaglandin E2 (PGE2), matrix metalloproteinase-13 (MMP-13), and substance P were also higher in comparison to the control group. The 2-aminoquinoline treatment supressed PGE2, MMP-13, and substance P levels in osteoarthritis rats. Moreover, the expression of phosphorylated nuclear factor kappaB (p-NF-κB) was markedly higher in the untreated rats. However, activation of NF-κB was downregulated in the osteoarthritis rats by treatment with 2-aminoquinoline.

Conclusions

The present study demonstrated that 2-aminoquinoline prevents articular cartilage damage in osteoarthritis rats through inhibition of inflammatory factors and downregulation of NF-κB activation, suggesting that 2-aminoquinoline would be effective in treatment of osteoarthritis.

Profile of Matrix-Remodeling Proteinases in Osteoarthritis: Impact of Fibronectin

The extracellular matrix (ECM) is a complex and specialized three-dimensional macromolecular network, present in nearly all tissues, that also interacts with cell surface receptors on joint resident cells. Changes in the composition and physical properties of the ECM lead to the development of many diseases, including osteoarthritis (OA). OA is a chronic degenerative rheumatic disease characterized by a progressive loss of synovial joint function as a consequence of the degradation of articular cartilage, also associated with alterations in the synovial membrane and subchondral bone. During OA, ECM-degrading enzymes, including urokinase-type plasminogen activator (uPA), matrix metalloproteinases (MMPs), and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs), cleave ECM components, such as fibronectin (Fn), generating fibronectin fragments (Fn-fs) with catabolic properties. In turn, Fn-fs promote activation of these proteinases, establishing a degradative and inflammatory feedback loop. Thus, the aim of this review is to update the contribution of ECM-degrading proteinases to the physiopathology of OA as well as their modulation by Fn-fs.

Cartilage protective and anti-analgesic effects of ALM16 on monosodium iodoacetate induced osteoarthritis in rats

Background

Osteoarthritis (OA) is an age-related joint disease with characteristics that involve the progressive degradation of articular cartilage and resulting chronic pain. Previously, we reported that Astragalus membranaceus and Lithospermum erythrorhizon showed significant anti-inflammatory and anti-osteoarthritis activities. The objective of this study was to examine the protective effects of ALM16, a new herbal mixture (7:3) of ethanol extracts of A. membranaceus and L. erythrorhizon, against OA in in vitro and in vivo models.

Methods

The levels of matrix metalloproteinase (MMP)-1, −3 and − 13 and glycosaminoglycan (GAG) in interleukin (IL)-1β or ALM16 treated SW1353 cells were determined using an enzyme-linked immunosorbent and quantitative kit, respectively. In vivo, the anti-analgesic and anti-inflammatory activities of ALM16 were assessed via the acetic acid-induced writhing response and in a carrageenan-induced paw edema model in ICR mice, respectively. In addition, the chondroprotective effects of ALM16 were analyzed using a single-intra-articular injection of monosodium iodoacetate (MIA) in the right knee joint of Wister/ST rat. All samples were orally administered daily for 2 weeks starting 1 week after the MIA injection. The paw withdrawal threshold (PWT) in MIA-injected rats was measured by the von Frey test using the up-down method. Histopathological changes of the cartilage in OA rats were analyzed by hematoxylin and eosin (H&E) staining.

Results

ALM16 remarkably reduced the GAG degradation and MMP levels in IL-1β treated SW1353 cells. ALM16 markedly decreased the thickness of the paw edema and writhing response in a dose-dependent manner in mice. In the MIA-induced OA rat model, ALM16 significantly reduced the PWT compared to the control group. In particular, from histological observations, ALM16 showed clear improvement of OA lesions, such as the loss of necrotic chondrocytes and cartilage erosion of more than 200 mg/kg b.w., comparable to or better than a positive drug control (JOINS™^, 200 mg/kg) in the cartilage of MIA-OA rats.

Conclusions

Our results demonstrate that ALM16 has a strong chondroprotective effect against the OA model in vitro and in vivo, likely attributed to its anti-inflammatory activity and inhibition of MMP production.