Human Synovial Fibroblast Cell Research Articles

Targeting TNF-α-induced expression of TTR and RAGE in rheumatoid arthritis: Apigenin's mediated therapeutic approach

BackgroundRheumatoid arthritis (RA) is a chronic inflammatory disease induced by TNF-α, which increases fibroblast-like synoviocytes inflammation, resulting in cartilage destruction. The current work sought to comprehend the pathophysiological importance of TNF-α stimulation on differential protein expression and their regulation by apigenin using in-vitro and in-vivo models of RA. MethodsThe human RA synovial fibroblast cells were stimulated with or without TNF-α (10 ng/ml) and treated with 40 μM apigenin. In-silico, in-vitro and in-vivo studies were performed to confirm the pathophysiological significance of apigenin on pro-inflammatory cytokines and on differential expression of TTR and RAGE proteins. ResultsTNF-α induced inflammatory response in synoviocytes revealed higher levels of IL-6, IL-1β, and TNF-α cytokines and upregulated differential expression of TTR and RAGE. In-silico results demonstrated that apigenin has a binding affinity towards TNF-α, indicating its potential effect in the inflammatory process. Both in-vitro and in-vivo results obtained by Western Blot analysis suggested that apigenin reduced the level of p65 (p = 0.005), TTR (p = 0.002), and RAGE (p = 0.020). ConclusionThe findings of this study suggested that TNF-α promotes the differential expression of pro-inflammatory cytokines, TTR, and RAGE via NF-kB pathways activation. Anti-inflammatory effect of apigenin impedes TNF-α mediated dysregulation or expression associated with RA pathogenesis.

New biflavonoids isolated from Xylia kerrii leaves extract with selective cytotoxicity against MH7A human rheumatoid arthritis synovial fibroblast cells.

Three new biflavonoids (1-3) and two known flavonoids (4, 5) were isolated from Xylia kerrii collected in Thailand. Compounds 1-5 showed selective cytotoxicity against the rheumatoid fibroblast-like synovial MH7A cell line, and these compounds showed weak cytotoxicity against the human lung synovial fibroblast WI-38 VA13 sub 2 RA cell line. Notably, compound 1 was highly selective toward MH7A cells with an IC50 value of 6.9μM, whereas the IC50 value for WI-38 VA13 sub 2 RA cells was > 100μM. The western blotting analysis of MH7A cells treated with compound 1 showed increased CDKN2A /p16INK4A and caspase-8 levels.

Inhibition of Oxidative Stress-Induced Ferroptosis Can Alleviate Rheumatoid Arthritis in Human.

Rheumatoid arthritis (RA) is a chronic autoimmunity illness, mainly featured with synovitis of the joint. The specificity of ferroptosis is disparate in different diseases, and the mechanism of ferroptosis in RA has some uncertainty yet. Therefore, the mechanism of ferroptosis was deeply observed in RA patients and animal models. In this paper, plasma of RA patients, the tumor necrosis factor-alpha-induced human synovial fibroblasts, and an animal model of arthritis induced by collagen were applied to initially inquire about the therapeutic effect of ferroptosis. For the RA patients, ELISA detected protein expression of glutathione (GSH), GPX4, Nrf2, Keap-1, and ferritin. In cell experiments, erastin or fer-1 regulated the invasion of human synovial fibroblast cells, mitochondrial membrane potential, reactive oxygen species (ROS) expression, marker protein, and so on. For the animal experiments, 32 Sprague-Dawley male rats were randomly separated into four groups with a collagen-induced RA model for 14 days and administered with erastin or fer-1 for 35 days. The expressions of GSH, GPX4, Nrf2, and Keap-1 were lower, and the ferritin was higher in RA patients, and the expressions of these proteins varied significantly after disease remission. In addition, ferroptosis inactivation also reduced the proliferation and migration ability, mitochondrial membrane potential, and ROS in cells. We discovered unexpectedly that activation of ferroptosis meaningfully forbore the foot swelling in animals with CIA, reduced arthritis scores, destruction of bone, and articular synovitis, and also decreased the high expression of inflammatory factors in plasma. There is a nonlinear relationship between human disease manifestations and animal model pathology. Ferroptosis regulating in RA for humans or animals may produce different effects.

Retracted: PRP from Personal Blood Relieves Joint Fluid-Inducing Synovial Injury through NF-κB Pathway and Mitochondrial Apoptosis in Human Synovial Fibroblast Cells.

[This retracts the article DOI: 10.1155/2022/4496949.].

PRP from Personal Blood Relieves Joint Fluid-Inducing Synovial Injury through NF-κB Pathway and Mitochondrial Apoptosis in Human Synovial Fibroblast Cells.

Background Platelet-rich plasma (PRP) therapy is a new kind of biological therapy to retune the plasma concentrator into the patient's body for the treatment of osteoarthritis diseases. The present research aimsed to confirm the treatment effects of PRP against osteoarthritis injury and elucidate its potential mechanism via constructing a kind of cellular injury model of human synovial fibroblast cells (HSF cells) induced by synovial fluid from osteoarthritis patients. Materials and Methods HSF cells wereas firstly treated with the different doses of synovial fluid from osteoarthritis patients, and evaluated for the cellular injury via cell morphology and MTT assay. And then, the protective effect of PRP against cellular injury were examined by cell morphology and MTT assay. Following, flow cytometry and western blot assay were employed to evaluate the effect of PRP on mitochondrial apoptosis. Finally, the effect of PRP on NF-κB pathway-associated inflammation wasere examined by Elisa ELISA assay and western blot. Results The dilution ratio 1 : 5 of synovial fluid displayed an excellent injury effect against HSF cells and selected as the model condition. The data from cellular image and MTT assay showed that PRP with the doses 1 : 5 and 1 : 10 could alleviate the cellular mounts decrease in the damaged HSF cells. Flow cytometry, western blot, and Elisa ELISA assay displayed that PRP could relieve the cellular mitochondrial apoptosis and NF-κB pathway-associated inflammation in the damaged HSF cells. Conclusion PRP might relieve HSF cells injury induced by synovial fluid from osteoarthritis patients through alleviating the mitochondrial apoptosis and NF-κB pathway-associated inflammation.

N1-methylpseudouridine-incorporated mRNA enhances exogenous protein expression and suppresses immunogenicity in primary human fibroblast-like synoviocytes.

Studies conducted using murine arthritis models have indicated that the use of in vitro-transcribed messenger RNA (IVT mRNA) is an effective therapeutic approach for joint diseases. However, the use of IVT mRNA in human synovial cells has not been widely studied. Recently, the outbreak of the novel coronavirus disease has accelerated the development of innovative mRNA vaccines, such as those containing a modified nucleic acid, N1-methylpseudouridine-5′-triphosphate (m1ψ). IVT mRNA is an attractive tool for biological experiments and drug discovery. To verify the protein expression from IVT mRNA in vitro, primary cultured fibroblast-like synoviocytes (FLS) and MH7A human synovial fibroblast cells were transfected with enhanced green fluorescent protein (EGFP) mRNA with or without m1ψ incorporation. EGFP was detected using western blotting and fluorescence microscopy. A multiplex assay was performed to comprehensively understand IVT mRNA-induced immunogenicity. Gene expression levels were measured using reverse transcription polymerase chain reaction. In both MH7A cells and FLS, cells transfected with EGFP mRNA containing m1ψ generated higher levels of EGFP than those transfected with unmodified EGFP or control mRNAs. The multiplex assay of the FLS culture supernatant and reverse transcription polymerase chain reaction for FLS revealed that both concentration and expression of IL-6, TNF-α, and CXCL10 were upregulated by unmodified EGFP mRNA, whereas they were suppressed by EGFP mRNA with m1ψ. Overall, m1ψ incorporation enhanced protein expression and decreased the expression of cytokines. These findings may contribute to arthritis research.

Loss of microRNA-147 function alleviates synovial inflammation through ZNF148 in rheumatoid and experimental arthritis.

MicroRNA-147 (miR-147) had been previously found induced in synoviocytes by inflammatory stimuli derived from Tcells in experimental arthritis. This study was designed to verify whether loss of its function might alleviate inflammatory events in joints of experimental and rheumatoid arthritis (RA). Dark Agouti (DA) rats were injected intradermally with pristane to induce arthritis, and rno-miR-147 antagomir was locally administrated into individual ankle compared with negative control or rno-miR-155-5p antagomir (potential positive control). Arthritis onset, macroscopic severity, and pathological changes were monitored. While in vitro, gain or loss function of hsa-miR-147b-3p/hsa-miR-155-5p and ZNF148 was achieved in human synovial fibroblast cell line SW982 and RA synovial fibroblasts (RASF). The expression of miRNAs and mRNAs was detected by using RT-quantitative PCR, and protein expression was detected by using Western blotting. Anti-miR-147 therapy could alleviate the severity, especially for the synovitis and joint destruction in experimental arthritis. Gain of hsa-miR-147b-3p/hsa-miR-155-5p function in TNF-α stimulated SW982 and RASF cells could upregulate, in contrast, loss of hsa-miR-147b-3p/hsa-miR-155-5p function could downregulate the gene expression of TNF-α, IL-6, MMP3, and MMP13. Hence, such alteration could participate in synovial inflammation and joint destruction. RNAi of ZNF148, a miR-147's target, increased gene expression of TNF-α, IL-6, MMP3, and MMP13 in SW982 and RASF cells. Also, mRNA sequencing data showed that hsa-miR-147b-3p mimic and ZNF148 siRNA commonly regulated the gene expression of CCL3 and DEPTOR as well as some arthritis and inflammation-related pathways. Taken together, miR-147b-3p contributes to synovial inflammation through repressing ZNF148 in RA and experimental arthritis.

Serum starvation raises turnover of phosphorylated p62/SQSTM1 (Serine 349), reveals expression of proteasome and N-glycanase1 interactive protein RAD23B and sensitizes human synovial fibroblasts to BAY 11-7085-induced cell death.

Phosphorylation of p62/SQSTM1 (p62) on Serine 349 (P-Ser349 p62) as well as proteasome dysfunction have been shown to activate the cell protective Keap1/Nrf2 pathway. We showed previously that BAY 11-7085-induced human synovial fibroblast cell death includes autophagy and p62 downregulation. In this work, we have studied expression of P-Ser349 p62 in human synovial fibroblasts. Results showed that P-Ser349 p62 was not detected in synovial cell extracts unless cells were cultured in the presence of proteasome inhibitor (MG132). MG132 revealed P-Ser349 p62 turnover, that was further increased by concomitant autophagy inhibition and markedly enhanced in serum starved cells. Starvation sensitized synovial fibroblasts to BAY 11-7085 while MG132 protected both non-starved and starved cells from BAY 11-7085-induced cell death. Lentivirus mediated overexpression of phosphorylation-mimetic p62 mutant S349E markedly protected synovial fibroblasts from BAY 11-7085. Inhibitor of Keap1-P-S349 p62 interaction, K67, had synergistic effect with MG132. Starvation increased p62 molecular weight, that was reversed by serum and bovine serum albumin re-feeding. Furthermore, starvation markedly induced RAD23B. Increased endo-β-N-acetylglucosaminidase (ENGase) turnover was detected in starved synovial fibroblasts. PNGase F treatment produced faster migration p62 form in human synovial tissue extracts but starvation-like p62 form of higher molecular weight in synovial cell extracts. Co-transfection of NGLY1, with p62 or p62 mutants S349A and S349E markedly stabilized p62 expressions in HEK293 cells. Tunicamycin upregulated p62 and protected synovial fibroblasts from BAY 11-7085-induced cell death. These results showed that P-Ser349 p62 has pro-survival role in human synovial fibroblasts and that de-glycosylation events are involved in p62 turnover.

Effects of sesamin on primary human synovial fibroblasts and SW982 cell line induced by tumor necrosis factor-alpha as a synovitis-like model

BackgroundRheumatoid arthritis (RA) is an autoimmune disease that causes chronic synovitis, cartilage degradation and bone deformities. Synovitis is the term for inflammation of the synovial membrane, an early stage of RA. The pathogenesis of the disease occurs through cytokine induction. The major cytokine that increases the severity of RA is TNF-α. Thus, inhibition of the TNF-α cascade is an effective way to diminish the progression of the disease. We are interested in investigating the difference between primary human synovial fibroblast (hSF) cells and SW982 as synovitis models induced by TNF-α and in monitoring their responses to sesamin as an anti-inflammatory phytochemical.MethodThe designed experiments were performed in hSF cells or the SW982 cell line treated with 10 ng/ml TNF-α with or without 0.25, 0.5 or 1 μM sesamin. Subsequently, pro-inflammatory cytokine genes and proteins were measured in parallel with a study of associated signalling transduction involved in inflammatory processes, including NF-κB and MAPK pathways.ResultsThe results demonstrated that although hSF and SW982 cells responded to TNF-α induction in the same fashion, they reacted at different levels. TNF-α could induce IL-6, IL-8 and IL-1β in both cell types, but the levels in SW982 cells were much higher than in hSF cells. This characteristic was due to the different induction of MAPKs in each cell type. Both cell types reacted to sesamin in almost the same fashion. However, hSF cells were more sensitive to sesamin than SW982 cells in terms of the anti-RA effect.ConclusionsThe responses of TNF-α-induced hSF and SW982 were different at the signal transduction level. However, the two cell types showed almost the same reaction to sesamin treatment in terms of the end point of the response.

The inhibitory effect of Aconiti Sinomontani Radix extracts on the proliferation and migration of human synovial fibroblast cell line SW982

Ethnopharmacological relevanceAconiti Sinomontani Radix is frequently used in the treatment of Bi syndrome in traditional Chinese medicine. Several reports indicate that Aconiti Sinomontani Radix has therapeutic effects for rheumatoid arthritis (RA). However, the cellular mode of action is still unclear. To investigate the effect of alkaloid extracts of Aconiti Sinomontani Radix on proliferation and migration of human synovial sarcoma SW982 cells as well as the molecular mechanism underlying. Materials and methodsSW982 cells were examined for proliferation by a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) method. Wound scratch assays were performed to assess the migrated rate of SW982 cells. Quantitative real-time PCR was used to measure the mRNA expression levels of Wnt5a, Runx2, MMP3, and Bmp2. Western blotting was used to measure the phosphorylated levels of JNK and NF-κB as well as the expression of MMP3. ResultsThe alkaloid extract from Aconiti Sinomontani Radix (MQA) and MQB, which removed lappaconitine from MQA significantly inhibited the proliferation of SW982 in a dose-dependent manner. The proliferation inhibitory effect of MQB was more potent. Incubation with 10μg/ml MQB for 12, 24, and 36h inhibited the migration of SW982 cells by 83%, 58%, and 42%, respectively. Treatment with different concentrations of MQB for 24h inhibited mRNA expression of Wnt5a, Runx2, and MMP3, but Bmp2 mRNA expression was elevated by MQB. Further, MQB inhibited phosphorylation of JNK and NF-κB p65 as well as MMP3 expression by Western blotting analysis. ConclusionThe results showed that MQB inhibited proliferation and migration of SW982 cells possibly through suppressing Wnt5a-mediated JNK and NF-κB pathways. These results indicated that MQB might be an active extract of Aconiti Sinomontani Radix for targeting fibroblast-like synoviocytes (FLS) and be potential for RA therapy.

Correction: Oleuropein down-regulated IL-1β-induced inflammation and oxidative stress in human synovial fibroblast cell line SW982.

Correction for 'Oleuropein down-regulated IL-1β-induced inflammation and oxidative stress in human synovial fibroblast cell line SW982' by Maria Luisa Castejón, et al., Food Funct., 2017, DOI: 10.1039/c7fo00210f.

Oleuropein down-regulated IL-1β-induced inflammation and oxidative stress in human synovial fibroblast cell line SW982.

Rheumatoid arthritis (RA) is a chronic and systemic inflammatory autoimmune disease mainly characterized by aggressive hyperproliferation of synovial fibroblasts (SFs). It is accompained by a massive infiltration of inflammatory immune cells inducing progressive matrix degradation, destruction of cartilage and bone erosion through the production of inflammatory mediators. Oleuropein is the most prevalent phenolic component in olive leaves, seed, pulp and peel of unripe olives and is responsible for the characteristic bitter taste of unprocessed olives. This secoiridoid possesses well-documented pharmacological properties, including antioxidant and anti-inflammatory properties, and is available as a food supplement in Mediterranean countries. However, to date, anti-arthritic effects of oleuropein on SFs have not been yet elucidated. Thus, the aim of the present study was to investigate the potential effects of oleuropein, on IL-1β-induced production of inflammatory mediators and oxidative stress in the human synovial sarcoma cell line (SW982). In order to gain a better insight into mechanisms of action, signaling pathways were also explored. Cell viability was determined using the sulforhodamine B (SRB) assay. The expression of inflammatory cytokines IL-6, TNF-α, MMP-1 and MMP-3 was evaluated by ELISA. Moreover, changes in the protein expression of cyclooxygenase (COX)-2, microsomal prostaglandin E synthase-1 (mPGES-1) as well as mitogen-activated protein kinase (MAPKs), nuclear factor kappa B (NF-κB), and nuclear factor-erythroid 2-related and heme oxygenase-1 (HO-1) signalling pathways were analysed by western blot. Oleuropein exerted anti-inflammatory and anti-oxidant effects via down-regulation of MAPK and NF-κB signaling pathways and induction of Nrf2-linked HO-1 controlling the production of inflammatory mediators decreasing IL-6 and TNF-α cytokines, MMP-1 and MMP-3 levels and mPGES-1 and COX-2 overexpression. Thus, oleuropein might provide a basis for developing a new dietary strategy for the prevention and management of RA.

Dimacrolide Sesquiterpene Pyridine Alkaloids from the Stems of Tripterygium regelii.

Two new dimacrolide sesquiterpene pyridine alkaloids (DMSPAs), dimacroregelines A (1) and B (2), were isolated from the stems of Tripterygium regelii. The structures of both compounds were characterized by extensive 1D and 2D NMR spectroscopic analyses, as well as HRESIMS data. Compounds 1 and 2 are two rare DMSPAs possessing unique 2-(3′-carboxybutyl)-3-furanoic acid units forming the second macrocyclic ring, representing the first example of DMSPAs bearing an extra furan ring in their second macrocyclic ring system. Compound 2 showed inhibitory effects on the proliferation of human rheumatoid arthritis synovial fibroblast cell (MH7A) at a concentration of 20 μM.

BAY 11-7085 induces glucocorticoid receptor activation and autophagy that collaborate with apoptosis to induce human synovial fibroblast cell death.

Inhibition of proapoptotic pathways in synovial fibroblasts is one of the major causes of synovial proliferation and hyperplasia in rheumatic diseases. We have shown previously that NF-κB inhibitor BAY 11-7085, through inactivation of PPAR-γ, induces apoptosis in human synovial fibroblasts. In this work we showed that BAY 11-7085 induced autophagy that preceded BAY 11-7085-induced apoptosis. Of interest, BAY 11-7085 induced Serine 211 phosphorylation and degradation of glucocorticoid receptor (GR). Glucocorticoid prednisolone induced both activation and degradation of GR, as well as autophagy in synovial fibroblasts. BAY 11-7085-induced cell death was significantly decreased with glucocorticoid inhibitor mifepristone and with inhibitors of autophagy. Both BAY 11-7085-induced autophagy and GR activation were down regulated with PPAR-γ agonist, 15d-PGJ2 and MEK/ERK inhibitor UO126. Inhibition of autophagy markedly decreased endogenous and BAY 11-7085-induced ERK phosphorylation, suggesting a positive feed back loop between ERK activation and autophagy in synovial fibroblasts. Co-transfection of MEK1 with PPAR-γ1 in HEK293 cells caused known inhibitory phosphorylation of PPAR-γ1 (Serine 112) and enhanced GR degradation, in the absence or presence of prednisolone. Furthermore, GR was both phosphorylated on Serine 211 and down regulated in synovial fibroblasts during serum starvation induced autophagy. These results showed that GR activation and PPAR-γ inactivation mediated BAY 11-7085-induced autophagy.

Immunomodulatory effects of bee venom in human synovial fibroblast cell line.

As in Iranian traditional medicine, bee venom (BV) is a promising treatment for the rheumatoid arthritis (RA) which is considered as a problematic human chronic inflammatory disease in the present time. Smoking is considered to be a major risk factor in RA onset and severity. The main aim of this study is to investigate the effects of BV on cigarette smoke-induced inflammatory response in fibroblast-like synoviocytes (FLS). Cytotoxicity of cigarette smoke condensate (CSC) and bee venom were determined by the tetrazolium (MTT) method in cultured synovial fibroblastes. The expression of interleukin-1β and sirtuin1 mRNA were analyzed by SYBR green real-time quantitative PCR. Differences between the mean values of treated and untreated groups were assessed by student t-test. Based on MTT assay, CSC and BV did not exert any significant cytotoxic effects up to 40 µg/mL and 10 µg/mL, respectively. Our results showed that interleukin-1β mRNA level was significantly up-regulated by CSC treatments in LPS-stimulated synoviocytes in a dose-dependent manner. Conversely, the expressions of IL-1β and Sirt1 were up-regulated even in lower concentrations of BV and attenuated at higher concentrations. Also, BV attenuated the CSC-induced and LPS-induced inflammatory responses in synovial fibroblasts. Our results support the epidemiological studies indicating pro-inflammatory effects of CSC and anti-inflammatory effects of BV on FLS cell line.

Anti-inflammatory effects of a novel ricinoleic acid poloxamer gel system for transdermal delivery

Our previous study showed that the use of ricinoleic acid as an oil phase resulted in the formation of a stable pluronic lecithin organogel (PLO gel) with better thixotropic properties and higher permeation of ketoprofen than the isopropyl palmitate PLO gel. This study aims to evaluate and compare the in vitro and in vivo anti-inflammatory effects of the ricinoleic acid PLO gel system with isopropyl palmitate PLO gel. Ketoprofen was used as a model drug. In vitro anti-inflammatory activity and cell viability tests were performed in human rheumatoid arthritis synovial fibroblast cell line using a blank ricinoleic acid PLO gel and compared to that of the isopropyl palmitate PLO gel. In vivo anti-inflammatory activity of ricinoleic acid PLO gel containing 10% ketoprofen was evaluated and compared with the isopropyl palmitate PLO gel in a carrageenan-induced rat paw edema model. The results from the in vitro study showed that the blank ricinoleic acid PLO gel possessed significantly higher anti-inflammatory activity than isopropyl palmitate PLO gel at 1mM concentration (p<0.05), while both the gel formulations had no significant cytotoxic activity. Further in vivo testing of the formulation showed that the ricinoleic acid PLO gel formulation was significantly more effective in reducing pain and edema when compared to the isopropyl palmitate PLO gel. In addition, the ricinoleic acid PLO gel formulation markedly inhibited the synthesis of prostaglandin E2. In conclusion, the efficacy of PLO gels used in pain management may be enhanced by using ricinoleic acid instead of isopropyl palmitate as an oil phase.

Connexin43 enhances the expression of osteoarthritis-associated genes in synovial fibroblasts in culture.

BackgroundRecent work has shown that the gap junction protein connexin43 (Cx43) is upregulated in cells of the joint during osteoarthritis (OA). Here we examined if the OA-associated increase in Cx43 expression impacts the function of synovial fibroblasts by contributing to the production of catabolic and inflammatory factors that exacerbate joint destruction in arthritic disease.MethodsUsing rabbit and human synovial fibroblast cell lines, we examined the effects of Cx43 overexpression and Cx43 siRNA-mediated knockdown on the gene expression of OA-associated matrix metalloproteinases (MMP1 and MMP13), aggrecanases (ADAMTS4 and ADAMTS5), and inflammatory factors (IL1, IL6 and PTGS2) by quantitative real time RT-PCR. We examined collagenase activity in conditioned media of cultured synovial cells following Cx43 overexpression. Lastly, we assessed the interplay between Cx43 and the NFκB cascade by western blotting and gene expression studies.ResultsIncreasing Cx43 expression enhanced the gene expression of MMP1, MMP13, ADAMTS4, ADAMTS5, IL1, IL6 and PTGS2 and increased the secretion of collagenases into conditioned media of cultured synovial fibroblasts. Conversely, knockdown of Cx43 decreased expression of many of these catabolic and inflammatory genes. Modulation of Cx43 expression altered the phosphorylation of the NFκB subunit, p65, and inhibition of NFκB with chemical inhibitors blocked the effects of increased Cx43 expression on the mRNA levels of a subset of these catabolic and inflammatory genes.ConclusionsIncreasing or decreasing Cx43 expression alone was sufficient to alter the levels of catabolic and inflammatory genes expressed by synovial cells. The NFκB cascade mediated the effect of Cx43 on the expression of a subset of these OA-associated genes. As such, Cx43 may be involved in joint pathology during OA, and targeting Cx43 expression or function may be a viable therapeutic strategy to attenuate the catabolic and inflammatory environment of the joint during OA.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2474-15-425) contains supplementary material, which is available to authorized users.

AB0134 Affibody Molecules Inhibiting the Interaction between RAS and RAF Suppress the Proliferation and the Production of Inflammatory Mediators by Synovial Cells

BackgroundRas proteins are present in rheumatoid arthritis (RA) synovial tissues, and are preferentially expressed in the intimal lining layer. Activation of Ras effecter pathways in synovial tissues, including MAP kinases,...

Anti-inflammatory and apoptotic effects of the polyphenol curcumin on human fibroblast-like synoviocytes

BackgroundIt has recently been reported that the polyphenol curcumin has pronounced anti-carcinogenic, anti-inflammatory and pro-apoptotic properties. This study investigated possible anti-inflammatory and apoptotic effects of curcumin on the human synovial fibroblast cell line MH7A, and on fibroblast-like synoviocytes (FLS) derived from patients with rheumatoid arthritis (RA). MethodsMH7A cells and RA-FLS were stimulated either with interleukin (IL)-1β or phorbol 12-myristate 13 acetate (PMA), and treated simultaneously or sequentially with increasing concentrations of curcumin. Release of interleukin (IL)-6 and vascular endothelial growth factor (VEGF)-A was quantified by enzyme-linked immunosorbent assays (ELISAs). In MH7A cells, modulation of the transcription factor nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinases (MAPKs) such as p38 and extracellular-signal regulated kinase (ERK1/2) were analysed by a reporter gene assay and Western blot, respectively. Pro-apoptotic events were monitored by Annexin-V/7-AAD based assay. Cleavage of pro-caspase-3 and −7 was checked with specific antibodies. ResultsCurcumin effectively blocked IL-1β and PMA-induced IL-6 expression both in MH7A cells and RA-FLS. VEGF-A expression could only be detected in RA-FLS and was induced by PMA, but not by IL-1β. Furthermore, curcumin inhibited activation of NF-κB and induced dephosphorylation of ERK1/2. Treatment of FLS with high concentrations of curcumin was associated with a decrease in cell viability and induction of apoptosis. ConclusionThe natural compound curcumin represents strong anti-inflammatory properties and induces apoptosis in FLS. This study provides an insight into possible molecular mechanisms of this substance and suggests it as a natural remedy for the treatment of chronic inflammatory diseases like RA.

High glucose induces vascular endothelial growth factor production in human synovial fibroblasts through reactive oxygen species generation

BackgroundDiabetes is an independent risk factor of osteoarthritis (OA). Angiogenesis is essential for the progression of OA. Here, we investigated the intracellular signaling pathways involved in high glucose (HG)-induced vascular endothelial growth factor (VEGF) expression in human synovial fibroblast cells. MethodsHG-mediated VEGF expression was assessed with qPCR and ELISA. The mechanisms of action of HG in different signaling pathways were studied using Western blotting. Knockdown of proteins was achieved by transfection with siRNA. Chromatin immunoprecipitation assays were used to study in vivo binding of c-Jun to the VEGF promoter. ResultsStimulation of OA synovial fibroblasts (OASF) with HG induced concentration- and time-dependent increases in VEGF expression. Treatment of OASF with HG increased reactive oxygen species (ROS) generation. Pretreatment with NADPH oxidase inhibitor (APO or DPI), ROS scavenger (NAC), PI3K inhibitor (Ly294002 or wortmannin), Akt inhibitor, or AP-1 inhibitor (curcumin or tanshinone IIA) blocked the HG-induced VEGF production. HG also increased PI3K and Akt activation. Treatment of OASF with HG increased the accumulation of phosphorylated c-Jun in the nucleus, AP-1-luciferase activity, and c-Jun binding to the AP-1 element on the VEGF promoter. ConclusionsOur results suggest that the HG increases VEGF expression in human synovial fibroblasts via the ROS, PI3K, Akt, c-Jun and AP-1 signaling pathway. General significanceWe link high glucose on VEGF expression in osteoarthritis.