Human Rheumatoid Fibroblast-like Synoviocytes Research Articles

Possible involvement of DExD/H box helicase 60 in synovial inflammation of rheumatoid arthritis: role of toll-like receptor 3 signaling.

Innate immunity is known to be implicated in the etiology of synovitis in rheumatoid arthritis (RA). However, details of the molecular mechanisms have not been fully clarified. DExD/H-box helicase 60 (DDX60), a putative RNA helicase, is of consequence in anti-viral innate immune reactions followed by inflammation. Although DDX60 is involved in the pathogenesis of autoimmune diseases such as systemic lupus nephritis, the role of DDX60 in RA has not been elucidated. The objective of this study was to examine the expression and the role of DDX60 in RA synovial inflammation. DDX60 protein expression was investigated by immunohistochemistry in synovial tissues resected from 4 RA and 4 osteoarthritis (OA) patients. We found that synovial DDX60 expression was more intense in RA than in OA. Treatment of human rheumatoid fibroblast-like synoviocytes in culture with polyinosinic-polycytidylic acid, a Toll-like receptor 3 (TLR3) ligand, increased DDX60 protein and mRNA expression. A knockdown experiment of DDX60 using RNA interference revealed a decrease in the expression of poly IC-induced C-X-C motif chemokine ligand 10 (CXCL10) which induces lymphocyte chemotaxis. The synovial DDX60 was more expressed in RA patients than in OA. In human RFLS, DDX60 stimulated by TLR3 signaling affected CXCL10 expression. DDX60 may contribute to synovial inflammation in RA.

Isolation, structure modification, and anti-rheumatoid arthritis activity of isopimarane-type diterpenoids from Orthosiphon aristatus

Orthosiphon aristatus is a well-known folkloric medicine and herb for Guangdong soup for the treatment of rheumatism in China. Eight isopimarane-type and migrated pimarane-type diterpenoids (1-8), including a new one with a rarely occurring α,β-unsaturated diketone C-ring, were isolated from O. aristatus. Their structures were determined by spectroscopic methods and quantum chemical calculations. Furthermore, the most abundant compound, orthosiphol K, was structurally modified by modern synthetic techniques to give seven new derivatives (9-15). The anti-rheumatoid arthritis activity of these diterpenoids were evaluated on a TNF-α induced MH7A human rheumatoid fibroblast-like synoviocyte model. Compound 10 showed the most potent activity among these compounds. Based on their inhibitory effects on the release levels of IL-1β, the preliminary structure-activity relationships were concluded. Furthermore, western blot analysis revealed that 10 could increase the expression of IκBα and decrease the expression of NF-κB p65, and the expression levels of COX-2 and NLRP3 proteins were consequently down-regulated.

Tumor Necrosis Factor and Interleukin-1β Upregulate NRP2 Expression and Promote SARS-CoV-2 Proliferation.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), utilizes the host receptor angiotensin-converting enzyme 2 (ACE2) and the auxiliary receptor Neuropilin-1 (NRP1) to enter host cells. NRP1 has another isoform, NRP2, whose function in COVID-19 has seldom been reported. In addition, although patients with severe cases of COVID-19 often exhibit increased levels of proinflammatory cytokines, the relationship between these cytokines and SARS-CoV-2 proliferation remains unknown. The aim of this study is to clarify the roles of proinflammatory cytokines in Neuropilin expressions and in SARS-CoV-2 infection. To identify the expression patterns of NRP under inflamed and noninflamed conditions, next-generation sequencing (RNA-seq), immunohistochemistry, quantitative real-time PCR, and Western blotting were performed using primary cultured fibroblast-like synoviocytes, MH7A (immortalized cell line of human rheumatoid fibroblast-like synoviocytes), immortalized MRC5 (human embryonic lung fibroblast), and synovial tissues. To measure viral proliferative capacity, SARS-CoV-2 infection experiments were also performed. NRP2 was upregulated in inflamed tissues. Cytokine-stimulated human fibroblast cell lines, such as MH7A and immortalized MRC5, revealed that NRP2 expression increased with co-stimulation of tumor necrosis factor α (TNFα) and interleukin-1 beta (IL-1β) and was suppressed with anti-TNFα antibody alone. TNFα and IL-1β promoted SARS-CoV-2 proliferation and Spike protein binding. The viral proliferation coincided with the expression of NRP2, which was modulated through plasmid transfections. Our results revealed that proinflammatory cytokines, including TNFα, contribute to NRP2 upregulation and SARS-CoV-2 proliferation in host human cells.

Potential pharmacodynamic substances of Laportea bulbifera in treatment of rheumatoid arthritis based on serum pharmacochemistry and pharmacology

The present study investigated the pharmacodynamic material basis of Laportea bulbifera in the treatment of rheumatoid arthritis. Firstly, human rheumatoid arthritis fibroblast-like synoviocyte line MH7A was cultured in vitro and treated with tumor necrosis factor alpha(TNF-α, 50 ng·mL~(-1)). The proliferation and the levels of inflammatory cytokines such as prostaglandin E2(PGE2), interleukin-1β(IL-1β), and interleukin-6(IL-6) of the MH7A cells exposed to the serum containing L. bulbifera were determined to evaluate the anti-rheumatoid arthritis effects of the serum. Furthermore, the ultra-performance liquid chromatography tandem mass spectrometry fingerprints of the L. bulbifera crude extract, the drug-containing serum, and the drug-free serum were compared to identify the compounds newly generated in the serum after oral administration of the extract. According to the peak areas of common peaks and the results of anti-rheumatoid arthritis effect test, the active components were identified. The serum containing L. bulbifera significantly inhibited the proliferation of the MH7A cells activated by TNF-α and the expression of PGE2, IL-6, and IL-1β. Thirty newly generated compounds were detected in the drug-containing serum. Among them, neochlorogenic acid, cryptochlorogenic acid, chlorogenic acid, rutin, isoquercitrin, luteoloside, kaempferol-3-O-rutinoside, and quercitrin were also present in the crude extract. Twelve characteristic peaks(3, 7, 8, 14, 18, 19, 21, 23, 24, m6, m7, and m15) were significantly correlated with the pharmaceutical effect. According to the correlations, neochlorogenic acid, cryptochlorogenic acid, and chlorogenic acid had great contributions to the anti-rheumatoid arthritis activity. This study preliminarily clarified the potential pharmacodynamic substances of L. bulbifera in the treatment of rheumatoid arthritis, which laid a theoretical and experimental foundation for further development and application of the medicinal plant.

NR2F2 Regulates Cell Proliferation and Immunomodulation in Whartons' Jelly Stem Cells.

(1) Background: Wharton’s Jelly stem cells (WJ-MSCs) are multipotent mesenchymal stem cells that can proliferate rapidly and have low immunogenicity. Therefore, WJ-MSCs have gained considerable attention in the fields of immunomodulation and disease treatment and have entered clinical trials for the treatment of various diseases. Therefore, it is crucial to study the underlying mechanisms of WJ-MSCs proliferation, immune regulation, and disease treatment. Nuclear Receptor Subfamily 2 Group F Member 2 (NR2F2) is a transcription factor that is involved in the regulation of many different genes. However, it remains unknown how NR2F2 regulates stem cell identity in WJ-MSCs. (2) Methods: We used RNAi technology to knock down NR2F2 in WJ-MSCs, and studied the regulatory role of NR2F2 in WJ-MSCs by MTT, flow cytometry, RNA-seq, and other methods. We also utilized a co-culture system in which NR2F2-depleted WJ-MSCs with MH7A and HCT116/HepG2 were used to investigate the role of NR2F2 in immunomodulation and the inhibition of cancer cell growth. (3) Results: NR2F2 knockdown resulted in decreased expressions of Cyclin D1 and CDK4, slower cell proliferation, and increased expressions of IL6 and IL8. Furthermore, Cyclin D1, CDK4, and inflammatory factors were increased in human rheumatoid fibroblast-like synoviocyte line MH7A if co-cultured with NR2F2 depleted WJ-MSCs. In addition, we observed increased p53, decreased BCL-2, and increased cell apoptosis in liver cancer cell line HepG2 if co-cultured with NR2F2-depleted WJ-MSCs. (4) Conclusions: NR2F2 not only plays an important role in the cell cycle and immune regulation of WJ-MSCs but also has potential effects on the WJ-MSCs treatment of related diseases.

Chinese Herbal Formula Huayu-Qiangshen-Tongbi Decoction Attenuates Rheumatoid Arthritis through Upregulating miR-125b to Suppress NF-κB-Induced Inflammation by Targeting CK2.

The Huayu-Qiangshen-Tongbi (HQT) decoction, a Chinese medical formula, has been identified to show a potent therapeutic effect on rheumatoid arthritis (RA). However, the specific molecular mechanism of HQT in RA has not been well studied. In the present study, LPS-treated human rheumatoid fibroblast-like synoviocyte (FLS) MH7A cells and collagen-induced arthritis (CIA) mice were utilized as in vitro and in vivo models. Our results demonstrated that HQT could efficiently inhibit RA-induced inflammation by reducing the production of cytokines including tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6). Moreover, HQT significantly upregulated the expression of miR-125b. Besides, analysis of bioinformatics suggested casein kinase 2 (CK2) was a potential target of miR-125b. Luciferase reporter assay was performed and revealed that miR-125b suppressed CK2 expression in MH7A cells. Furthermore, miR-125b inhibited LPS-induced NF-kappa-B (NF-κB) activation, which is a downstream target of CK2. In addition, the NF-κB inhibitor ammonium pyrrolidinedithiocarbamate (PDTC) and NF-kappa-B inhibitor alpha (IkB-α) enhanced the inhibitory effect of miR-125b on the expression of TNF-α, IL-1β, and IL-6. Taken together, our study revealed that HQT could attenuate RA through upregulating miR-125b to suppress NF-κB-induced inflammation by targeting CK2. The findings of this study should facilitate investigating the mechanism of HQT on RA and discovering novel therapeutic targets for RA.

Chelerythrine ameliorates rheumatoid arthritis by modulating the AMPK/mTOR/ULK-1 signaling pathway

BackgroundRheumatoid arthritis (RA) is a long-term, progressive, and disabling autoimmune disease. It causes inflammation, swelling and pain in and around the joints and other body organs. Currently, no cure is available for RA. Clinical interventions can only relieve the condition, and at least 30% of RA patients do not respond to first‑line therapy. This means that the development of more effective therapies against RA is urgently needed. ObjectiveThis study aimed to assess the anti-rheumatoid arthritis effect of chelerythrine (CLT) and explore its mechanism of action. MethodsThe cytotoxic effect of CLT on human rheumatoid arthritis fibroblast-like synoviocyte (HFLS-RA) cells and HFLS-normal cells were measured by MTT assay. The growth and migration of HFLS-RA cells were determined by colony-formation and wound-healing assay. The level of intracellular reactive oxygen species (ROS) was detected using the DCFH-DA reagent. Cell apoptosis was measured by flow cytometry, TUNEL staining, caspase 3 activity, as well as the activation of apoptosis related proteins. In addition, the levels of autophagy related markers such as LC3B and P62 were determined by immunocytochemistry and western blotting. Lastly, the anti-RA effect of CLT was evaluated in an Adjuvant-Induced Arthritis(AIA) rat model and the severity of arthritis was detected and quantified using macroscopic inspection and X‑ray imaging. ResultsWe discovered that treatment with CLT effectively inhibited the migration and colony-formation of the HFLS-RA cells and resulted in cell death. Moreover, CLT increased the intracellular level of ROS and the apoptotic rate of HFLS-RA by activating the AMPK/mTOR/ULK-1 signaling pathways. In vivo study showed CLT effectively ameliorated AIA in rats, protecting them from inflammation and bone damage. ConclusionOur study shows CLT is an effective agent for ameliorating RA in vitro and in vivo by modulation of the AMPK/mTOR/ULK-1 signaling pathway. These findings indicate that CLT is a great potential candidate for development as a therapeutic agent for the prevention and treatment of RA.

Role of MDA5 in regulating CXCL10 expression induced by TLR3 signaling in human rheumatoid fibroblast-like synoviocytes

C-X-C motif chemokine 10 (CXCL10) is an inflammatory chemokine and a key molecule in the pathogenesis of rheumatoid arthritis (RA). Melanoma differentiation-associated gene 5 (MDA5) is an RNA helicase that plays a role in innate immune and inflammatory reactions. The details of the regulatory mechanisms of CXCL10 production and the precise role of MDA5 in RA synovitis have not been fully elucidated. The aim of this study was to examine the role of MDA5 in regulating CXCL10 expression in cultured human rheumatoid fibroblast-like synoviocytes (RFLS). RFLS was stimulated with Toll-like receptor 3 (TLR3) ligand polyinosinic:polycytidylic acid (poly I:C), a synthetic double-stranded RNA mimetic. Expression of interferon beta (IFN-β), MDA5, and CXCL10 was measured by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blotting, and enzyme-linked immunosorbent assay. A neutralizing antibody of IFN-β and siRNA-mediated MDA5 knockdown were used to determine the role of these molecules in regulating CXCL10 expression downstream of TLR3 signaling in RFLS. Poly I:C induced IFN-β, MDA5, and CXCL10 expression in a concentration- and time-dependent manner. IFN-β neutralizing antibody suppressed the expression of MDA5 and CXCL10, and knockdown of MDA5 decreased a part of CXCL10 expression (p < 0.001). The TLR3/IFN-β/CXCL10 axis may play a crucial role in the inflammatory responses in RA synovium, and MDA5 may be partially involved in this axis.

The JNK pathway represents a novel target in the treatment of rheumatoid arthritis through the suppression of MMP-3

Background and aimThe pathophysiology of rheumatoid arthritis (RA) is characterized by excess production of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) by neutrophils and macrophages in synovium. Additionally, these cytokines promote the production of reactive oxygen species (ROS), and increased production of matrix metalloproteinases (MMPs), including MMP-3, in synoviocytes that result in joint destruction. There is limited information on how proteolytic enzymes such as MMP-3 can be regulated. We evaluated the effect of the antioxidant N-acetylcysteine (NAC) on RA and identified the relationship between the c-Jun N terminal kinase (JNK) pathway and MMP-3. We hypothesized that elucidating this relationship would lead to novel therapeutic approaches to RA treatment and management.MethodsWe investigated the effect of administering a low dose (1000 μM or less) of an antioxidant (NAC) to human rheumatoid fibroblast-like synoviocytes (MH7A cells). We also investigated the response of antioxidant genes such as nuclear factor erythroid -derived 2-related factor 2 (Nrf2) and Sequestosome 1 (p62). The influence of MMP-3 expression on the JNK pathway leading to joint destruction and the mechanisms underlying this relationship were investigated through primary dispersion culture cells collected from the synovial membranes of RA patients, consisting of rheumatoid arthritis-fibroblast-like synoviocytes (RA-FLS).ResultsLow-dose NAC (1000 μM) increased the expression of Nrf2 and phospho-p62 in MH7A cells, activating antioxidant genes, suppressing the expression of MMP-3, and inhibiting the phosphorylation of JNK. ROS, MMP-3 expression, and IL-6 was suppressed by administering 30 μM of SP600125 (a JNK inhibitor) in MH7A cells. Furthermore, the administration of SP600125 (30 μM) to RA-FLS suppressed MMP-3.ConclusionsWe demonstrated the existence of an MMP-3 suppression mechanism that utilizes the JNK pathway in RA-FLS. We consider that the JNK pathway could be a target for future RA therapies.

Investigation of toll-like receptor (TLR) 4 inhibitor TAK-242 as a new potential anti-rheumatoid arthritis drug

BackgroundProper blocking of toll-like receptor (TLR) activation during disease progression has been reported to have inhibitory effect on the pathogenesis of rheumatoid arthritis (RA). We tested whether the TLR4 inhibitor TAK-242 had potential as a remedy for rheumatoid arthritis.MethodsThe therapeutic effect of TAK-242 was tested in vitro using the human rheumatoid fibroblast-like synoviocyte (FLS) line MH7A or primary human FLS and in an adjuvant-induced arthritis (AIA) rat model.ResultsTAK-242 dose dependently inhibited the increased expression of IL-6, IL-8, MMP-1, and VEGF in LPS-stimulated MH7A cells. It also inhibited the expression of IL-6 and IL-8 in poly(I:C), TLR3 activator-stimulated primary FLS, but not in IL-1β-stimulated primary FLS. These findings suggest that TAK-242 blocks a specific signaling pathway to some degree. Further, TAK-242 slightly inhibited mobilization of NF-κB into nuclei. In the AIA rat model, TAK-242 significantly reversed the body weight and paw thickness of AIA rats to the normal state at a dose of 5 mg/kg, but not at 3 mg/kg, and reduced the increased serum level of IL-6 and VEGF in AIA rats. It also significantly ameliorated inflammatory symptoms of joint tissues at day 21 of treatment, according to histology and RT-PCR.ConclusionsBased on the drug repositioning concept, TAK-242, which is used for the treatment of TLR4-mediated inflammatory diseases, shows potential for cost-effective development as a remedy for rheumatoid arthritis or to control the progression of RA.

Melatonin attenuates TNF-α and IL-1β expression in synovial fibroblasts and diminishes cartilage degradation: Implications for the treatment of rheumatoid arthritis.

The hormone melatonin has many properties, including antioxidant, anti-inflammatory, and immunomodulatory effects. Melatonin has been demonstrated to be beneficial in several inflammatory autoimmune diseases, but its effects in rheumatoid arthritis (RA) remain controversial. We sought to determine how melatonin regulates inflammation in RA. We found that melatonin dose-dependently inhibits tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β expression through the PI3K/AKT, ERK, and NF-κB signaling pathways. We also identified that melatonin inhibits TNF-α and IL-1β production by upregulating miR-3150a-3p expression. Synovial tissue specimens from RA patients and culture of human rheumatoid fibroblast-like synoviocytes confirmed that the MT1 receptor is needed for the anti-inflammatory activities of melatonin. Importantly, melatonin also significantly reduced paw swelling, cartilage degradation, and bone erosion in the collagen-induced arthritis mouse model. Our results indicate that melatonin ameliorates RA by inhibiting TNF-α and IL-1β production through downregulation of the PI3K/AKT, ERK, NF-κB signaling pathways, as well as miR-3150a-3p overexpression. The role of melatonin as an adjuvant treatment in patients with RA deserves further clinical studies.

Cyanidin-3-glucoside inhibits inflammatory activities in human fibroblast-like synoviocytes and in mice with collagen-induced arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by joint tissue inflammation. Cyanidin-3-glucoside (C3G) is a major component in the flavonoid family and has shown anti-inflammatory, anti-oxidant and anti-tumour activity. In this study, we investigated the effects of C3G on lipopolysaccharides (LPS)-induced inflammation on human rheumatoid fibroblast-like synoviocytes (FLS) and on collagen-induced arthritis (CIA) mice model. We treated FLS with C3G followed by LPS induction, the expressions of tumour necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β) and IL-6 and the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) signalling pathway were analyzed. CIA was induced in mice and the arthritic mice were treated with C3G for 3weeks. The disease severity was compared between control and C3G treated mice. The serum levels of TNF-α, IL-1β and IL-6 were analyzed by ELISA. C3G inhibited LPS-induced TNF-α, IL-1β and IL-6 expression in FLS. Moreover, C3G inhibited LPS-induced p65 production and IκBa, p38, ERK and JNK phosphorylation. Administration of C3G significantly attenuated disease in mice with CIA and decreased the serum level of TNF-α, IL-1β and IL-6. C3G inhibited LPS-induced inflammation in human FLS by inhibiting activation of NF-κB and MAPK signalling pathway. C3G exhibited therapeutic effects in mice with CIA.

Brahma-related gene 1 induces apoptosis in a p53-dependent manner in human rheumatoid fibroblast-like synoviocyte MH7A.

Blocked apoptosis and aggressive inflammatory responses occur in fibroblast-like synoviocyte (FLS) of rheumatoid arthritis (RA) patients. Although Brahma-related gene 1 (BRG1) is considered as a tumor suppressor, few research covers its role in RA. This study aims to reveal effects and potential mechanisms of BRG1 in human FLS cell line MH7A.BRG1 expression in MH7A cells was altered by transfection of overexpression vectors or short hairpin RNAs (shRNAs). Cell viability and apoptosis were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry after transfection. Factors involved in inflammation and apoptosis were quantified by qPCR and Western blot. The interaction between BRG1 and p53 was assessed by immunoprecipitation (IP).Results showed that BRG1 overexpression significantly suppressed MH7A cell viability and induced apoptosis (P < 0.01), and its knockdown had opposite effects. BRG1 reduced mRNA levels of matrix metallopeptidase 3, TIMP metallopeptidase inhibitor 2, cyclooxygenase 2, and interleukin 6, implying its suppressive effects on inflammation. BRG1 interacted with and promoted p53 (P < 0.05). B-cell chronic lymphocytic leukemia/lymphoma 2 was suppressed (P < 0.05), while cytochrome c, caspase 3 (CASP3) and CASP9 were activated (P < 0.01) by BRG1. However, the regulation on these factors was abrogated by p53 knockdown (P < 0.01).These findings suggest that BRG1 may induce apoptosis and suppress inflammation in MH7A cells. Potential functional mechanisms involve the regulation of apoptotic factors by BRG1, which may depend on the recruitment and promotion of p53. This study provides the essential proof for applying BRG1 to the molecular therapy of RA.

S-propargyl-cysteine attenuates inflammatory response in rheumatoid arthritis by modulating the Nrf2-ARE signaling pathway

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disorder. Hydrogen sulfide (H2S), the third physiological gasotransmitter, is well recognized as an anti-inflammatory mediator in various inflammatory conditions. Herein, we explored the protective effects of S-propargyl-cysteine (SPRC, also known as ZYZ-802), an endogenous H2S modulator, on RA and determined the underlying mechanisms. In the present study, SPRC concentration-dependently attenuated inflammatory mediator expression, reactive oxidase species generation, and the expression and activity of matrix metalloproteinases (MMP)-9 in interleukin (IL)-1β-induced human rheumatoid fibroblast-like synoviocytes MH7A. In addition, SPRC blocked IL-1β-mediated migration and invasion of MH7A cells. As expected, the protective effects of SPRC were partially abrogated by DL-propargylglycine (PAG, a H2S biosynthesis inhibitor). In vivo study also demonstrated that SPRC treatment markedly ameliorated the severity of RA in adjuvant-induced arthritis rats, and this effect was associated with the inhibition of inflammatory response. We further identified that SPRC remarkably induced heme oxygenase-1 expression associated with the degradation of Kelch-like ECH-associated protein 1 (Keap1) and nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2); this effect was attributed to the sulfhydrylation of the cysteine residue of Keap1. Our data demonstrated for the first time that SPRC, an endogenous H2S modulator, exerted anti-inflammatory properties in RA by upregulating the Nrf2-antioxidant response element (ARE) signaling pathway.

Hyperoside exerts anti-inflammatory and anti-arthritic effects in LPS-stimulated human fibroblast-like synoviocytes in vitro and in mice with collagen-induced arthritis.

Hyperoside is a flavonol glycoside mainly found in plants of the genera Hypericum and Crataegus, which has shown anti-oxidant, anti-cancer and anti-inflammatory activities. In this study, we investigated the effects of hyperoside on human rheumatoid fibroblast-like synoviocytes (FLSs) in vitro and on mouse collagen-induced arthritis (CIA) in vivo. FLSs were isolated from primary synovial tissues obtained from rheumatoid arthritis (RA) patients and exposed to LPS (1 μg/mL). Cell viability and proliferation were measured with MTT and BrdU assay. Cell migration was assessed using wound-healing assay and Transwell assay. DNA binding of NF-κB was measured using a TransAM-NFkappaB kit. The localization of p65 subunit was detected with immunocytochemistry. CIA was induced in mice by primary immunization with Bovine Type II collagen (CII) emulsified in CFA, followed by a booster injection 3 weeks later. The arthritic mice were treated with hyperoside (25, 50 mg·kg(-1)·d(-1), ip) for 3 weeks, and the joint tissues were harvested for histological analysis. Hyperoside (10, 50, 100 μmol/L) dose-dependently inhibited LPS-induced proliferation and migration of human RA FLSs in vitro. Furthermore, hyperoside decreased LPS-stimulated production of TNF-α, IL-6, IL-1 and MMP-9 in the cells. Moreover, hyperoside inhibited LPS-induced phosphorylation of p65 and IκBα, and suppressed LPS-induced nuclear translocation of p65 and DNA biding of NF-κB in the cells. Three-week administration of hyperoside significantly decreased the clinical scores, and alleviated synovial hyperplasia, inflammatory cell infiltration and cartilage damage in mice with CIA. Hyperoside inhibits LPS-induced proliferation, migration and inflammatory responses in human RA FLSs in vitro by suppressing activation of the NF-κB signaling pathway, which contributes to the therapeutic effects observed in mice with CIA.

Methyl salicylate lactoside inhibits inflammatory response of fibroblast‐like synoviocytes and joint destruction in collagen‐induced arthritis in mice

Methyl salicylate 2-O-β-d-lactoside (MSL), whose chemical structure is similar to that of salicylic acid, is a natural product derivative isolated from a traditional Chinese herb. The aim of this study was to investigate the therapeutic effect of MSL in mice with collagen-induced arthritis (CIA) and explore its underlying mechanism. The anti-arthritic effects of MSL were evaluated on human rheumatoid fibroblast-like synoviocytes (FLS) in vitro and CIA in mice in vivo by obtaining clinical scores, measuring hind paw thickness and inflammatory cytokine levels, radiographic evaluations and histopathological assessments. Treatment with MSL after the onset of arthritis significantly prevented the progression and development of rheumatoid arthritis (RA) in CIA mice without megascopic gastric mucosa damage. In addition, MSL inhibited the production of pro-inflammatory mediators, the phosphorylation and translocation of NF-κB, and cell proliferation induced by TNF-α in FLS. MSL non-selectively inhibited the activity of COX in vitro, but was a more potent inhibitor of COX-2 than COX-1. MSL also inhibited the phosphorylation of inhibitor of NF-κB kinase, IκBα and p65, thus blocking the nuclear translocation of NF-κB in TNF-α-stimulated FLS. MSL exerts therapeutic effects on CIA mice, suppressing the inflammatory response and joint destruction by non-selectively inhibiting the activity of COX and suppressing activation of the NF-κB signalling pathway, but without damaging the gastric mucosa. Therefore, MSL has great potential to be developed into a novel therapeutic agent for the treatment of RA.

Reduction of IL-20 Expression in Rheumatoid Arthritis by Linear Polarized Infrared Light Irradiation.

Low-level laser is being evaluated for treating rheumatoid arthritis (RA). Recently, the linear polarized infrared light (Super Lizer, SL) irradiation may also be useful for RA treatment. However, the molecular mechanism underlying the effectiveness of SL on RA is unclear. It has been IL-20 may involved in RA disease progression. To understand how SL action, we constructed the experimental model in vitro using human rheumatoid fibroblast-like synoviocyte (MH7A) and collagen induced (CIA) RA rat in vivo. We examined the effect of SL irradiation on IL-20 gene expression in MH7A and IL-20 protein production in CIA) rat joints. MH7A was cultured and challenged with IL-1ß, then examined IL-20 and IL-20R mRNA level by DNA microarray. IL-20 protein expression was examined by immunohistochemistry using a specific antibody against rat IL-20. Scatter plot analysis demonstrated that an increase in IL-20 gene expression by IL-1ß was reduced by SL irradiation, but IL-20R did not show a significant change. The Immunohistochemical analysis demonstrated a strong IL-20 staining in synovial membrane tissue of CIA rat joint, and SL irradiation significantly reduced the staining. Since IL-20 has been identified as an important cytokine in the pathogenesis of RA, the reduction of IL-20 expression by SL irradiation may be one of mechanisms in reduction of inflammation in RA joints by SL irradiation suggesting that SL irradiation may be useful for RA therapy.

Sulfuretin, a major flavonoid isolated from Rhus verniciflua, ameliorates experimental arthritis in mice

AimSulfuretin, a major flavonoid isolated from Rhus verniciflua, is known to have anti-inflammatory effects. However, the mechanisms underlying the anti-inflammatory effect of sulfuretin on rheumatoid arthritis have not been elucidated. In this study we investigated whether sulfuretin treatment modulates the severity of arthritis in an experimental model. Main methodsWe evaluated the effects of sulfuretin on tumor necrosis factor-α (TNF-α)-treated human rheumatoid fibroblast-like synoviocytes (FLS) in vitro and on collagen-induced arthritis (CIA) mice in vivo. Key findingsIn vitro experiments demonstrated that sulfuretin suppressed the chemokine production, matrix metalloproteinase secretion, and cell proliferation induced by tumor necrosis factor-α in rheumatoid FLS. In addition, sulfuretin inhibited the osteoclast differentiation induced by macrophage colony-stimulating factor and receptor activator of NF-κB ligand in bone marrow macrophages. In mice with CIA, early intervention with sulfuretin prevented joint destruction, as evidenced by a lower cumulative disease incidence and an absence of diverse disease features based on hind paw thickness, radiologic and histopathologic findings, and inflammatory cytokine levels. In mice with established arthritis, sulfuretin treatment significantly reduced synovial inflammation and joint destruction. The in vitro and in vivo protective effects of sulfuretin were mediated by inhibition of the NF-κB signaling pathway. SignificanceThese results suggest that using sulfuretin to block the NF-κB pathway in rheumatoid joints reduces both inflammatory responses and joint destruction. Therefore, sulfuretin may have therapeutic value in preventing or delaying the progression of rheumatoid arthritis.

SPA0355, a thiourea analogue, inhibits inflammatory responses and joint destruction in fibroblast‐like synoviocytes and mice with collagen‐induced arthritis

NF-κB has been implicated as a therapeutic target for the treatment of rheumatoid arthritis. We previously synthesized a thiourea analogue, SPA0355, which suppressed NF-κB activity. Here we have assessed the anti-inflammatory and anti-arthritic effects of SPA0355. We evaluated the effects of SPA0355 on human rheumatoid fibroblast-like synoviocytes in vitro and on collagen-induced arthritis (CIA) in mice in vivo. In vitro experiments demonstrated that SPA0355 suppressed chemokine production, matrix metalloproteinase secretion and cell proliferation induced by TNF-α in rheumatoid fibroblast-like synoviocytes. In addition, SPA0355 inhibited osteoclast differentiation induced by macrophage colony-stimulating factor and the receptor activator of NF-κB ligand, in bone marrow macrophages. Mice with CIA that were pretreated with SPA0355 had a lower cumulative disease incidence and severity of arthritis, based on hind paw thickness, radiological and histopathological findings, and inflammatory cytokine levels, than mice treated with vehicle. Mice treated with SPA0355, after the onset of CIA, also showed significantly decreased disease incidence and joint oedema. The in vitro and in vivo protective effects of SPA0355 were mediated by inhibition of the NF-κB signalling pathway. Taken together, these results suggested that using SPA0355 to block the NF-κB pathway in rheumatoid joints reduced both the inflammatory responses and tissue destruction. Therefore, SPA0355 may have therapeutic value in preventing or delaying joint destruction in patients with rheumatoid arthritis.

Tacrolimus (FK506) inhibits interleukin-1β-induced angiopoietin-1, Tie-2 receptor, and vascular endothelial growth factor through down-regulation of JNK and p38 pathway in human rheumatoid fibroblast-like synoviocytes

ObjectThis study aimed to identify the regulatory effect of tacrolimus on the interleukin-1β (IL-1β)-induced expressions of angiopoietin-1 (Ang-1), Tie-2 receptor (Tie-2), and vascular endothelial growth factor (VEGF) in human rheumatoid fibroblast-like synoviocytes (FLS) and to determine the regulatory mechanism in the mitogen-activated protein kinases (MAPKs) signaling pathway. MethodsIL-1β-induced Ang-1, Tie-2, and VEGF expressions with and without tacrolimus were measured in cultured FLS using real time–polymerase chain reaction, enzyme-linked immunosorbent assay, Western blotting, and immunofluorescence staining. The effect of tacrolimus on the regulation of Ang-1, Tie-2 and VEGF expressions through the MAPK signaling pathway was identified by Western blotting and immunofluorescence staining. ResultsIL-1β appeared to induce marked expressions of Ang-1, Tie-2, and VEGF in cultured FLS. Tacrolimus significantly inhibited Ang-1, Tie-2, and VEGF mRNA and protein in cultured FLS treated with 10ng/ml IL-1β. In addition, expressions of these angiogenic molecules were shown to involve all three of the studied MAPK signaling pathways, including ERK, JNK, and p38. However, the inhibitory effects of tacrolimus on Ang-1, Tie-2, and VEGF proteins were regulated by blocking the phosphorylations of JNK and p38 MAPK, but not that of ERK. ConclusionThis study demonstrates that tacrolimus inhibits the expressions of Ang-1, Tie-2, and VEGF by blocking the activations of the IL-1β-mediated JNK and p38 MAPK pathways in human FLS. This suggests that tacrolimus contributes to the suppression of angiogenesis in the pathogenesis of RA.