[Etanercept inhibits synovial inflammation and reduces the expression of adhesion related molecules in synovial tissues of patients with rheumatoid arthritis]

OBJECTIVE

To observe the changes of synovial inflammation score and expression of related molecular markers in patients with rheumatoid arthritis treated with tumor necrosis factor (TNF) antagonist etanercept.

METHODS

Sixteen patients with rheumatoid arthritis received synovectomy in the knee under arthroscopy, of which 8 patients had been treated with etanercept before surgery (etanercept group) and the other 8 patients were given no etanercept or other biologics (non-biological agent group). The synovial tissues obtained from surgery were subjected to HE staining and immunohistochemical staining respectively, to assess Rooney's inflammation score and detect the expressions of proliferating cell nuclear antigen (PCNA), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and cadherin-11.

RESULTS

Rooney's score in etanercept group was significantly lower than that in non-biological agent group. The expressions of PCNA and cadherin-11 in synovial lining and sublining layers significantly decreased in etanercept group. Expressions of VCAM-1 and ICAM-1 had no significant difference in either synovial lining or sublining layer between the two groups. Clinical inflammatory markers including erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), platelet count (PLT) and disease activity score in 28 joints (DAS28) had no statistical correlation with Rooney's inflammation score.

CONCLUSION

Etanercept could effectively inhibit proliferation of synoviocytes and infiltration of lymphocytes in synovium of rheumatoid arthritis, and decrease the expressions of proliferation-and adhesion-related molecular markers, which histologically alleviated the synovial inflammation of rheumatoid arthritis. Clinical inflammatory markers might not fully reflect histological changes in the local synovial tissue.

Lithothamnion muelleri treatment ameliorates inflammatory and hypernociceptive responses in antigen-induced arthritis in mice

Rheumatoid Arthritis (RA) is a chronic disease characterized by persistent inflammation and pain. Alternative therapies to reduce these symptoms are needed. Marine algae are valuable sources of diverse bioactive compounds. Lithothamnion muelleri (Hapalidiaceae) is a marine algae with anti-inflammatory, antitumor, and immunomodulatory properties. Here, we investigated the potential anti-inflammatory and analgesic activities of L. muelleri in a murine model of antigen-induced arthritis (AIA) in mice. Our results demonstrate that treatment with L. muelleri prevented inflammation and hypernociception in arthritic mice. Mechanistically, the crude extract and the polysaccharide-rich fractions of L. muelleri may act impairing the production of the chemokines CXCL1 and CXCL2, and consequently inhibit neutrophil influx to the knee joint by dampening the adhesion step of leukocyte recruitment in the knee microvessels. Altogether our results suggest that treatment with L.muelleri has a potential therapeutic application in arthritis treatment.

Relation of Doppler ultrasound synovitis versus clinical synovitis with changes in native complement component levels in rheumatoid arthritis patients treated with biologic disease-modifying anti-rheumatic drugs

OBJECTIVES

The complement system plays a fundamental role in mediating the activity of rheumatoid arthritis (RA). Biologic therapy can reduce native complement component levels and its activation. We aimed to study the relation of Doppler ultrasound (US) synovitis versus clinical synovitis with changes in native complement component levels in RA patients on biologic therapy.

METHODS

This was a cross-sectional study. Ninety-seven consecutive patients with RA on biologic therapy for at least 3 months were recruited. Clinical, laboratory and Doppler US assessments were performed. The Disease Activity Score in 28 joints (DAS28), Simplified Disease Activity Index (SDAI) and a 12-joint US assessment were carried out. Synovitis was semiquantitatively scored in B-mode and power Doppler (PD) mode.

RESULTS

A significant decrease in native complement (i.e. C3 and C4) and C-reactive protein (CRP) levels was observed. This was highly significant for C3 decrease (p<0.0005), and C4 decrease (p<0.0005). Synovitis detected by PD US showed significant negative association with C3 change (p<0.008), where patients with higher C3 change were more likely to have PD US inactive status on assessment.

CONCLUSIONS

Our results suggested that disease inactive status determined by PD US but not by clinical assessment can be related with decrease in complement in RA patients treated with biologic therapy.

Suppressive effects of total alkaloids of Lycopodiastrum casuarinoides on adjuvant-induced arthritis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Lycopodiastrum casuarinoides is a folk medicine used to treat inflammation-associated diseases including rheumatoid arthritis in South China. Since the major secondary metabolites in Lycopodiastrum casuarinoides are alkaloids, the present study aims to investigate the suppressive effects of total alkaloids of Lycopodiastrum casuarinoides (ALC) on adjuvant-induced arthritis (AA) in rats.

MATERIALS AND METHODS

AA was induced (day 0) in male Sprague-Dawley rats by intradermal injection of complete Freund׳s adjuvant (CFA) in right hind footpad. Diclofenac sodium (SD) was chosen as the positive drug. SD (10mg/kg) and ALC (20 and 40 mg/kg) administration started from day 1 and continued for 28 days. Paw swelling, arthritis scores, and histopathological changes were evaluated. In addition, the serum levels of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and prostaglandin E2 (PGE2), as well as cyclooxygenase-2 (COX-2) and nuclear factor (NF)-κB expressions in joint synovial tissues were detected.

RESULTS

ALC administration significantly suppressed the inflammatory responses in the joints of AA rats. It also decreased the serum levels of TNF-α, IL-6 and PGE2. Moreover, Western blot analysis showed that COX-2 and NF-κB expressions in synovial tissues of AA rats were significantly reduced.

CONCLUSION

These results indicated that ALC prevented the pathological development of AA in rats. ALC may be a potential candidate for the treatment of inflammation and arthritis.

[Flavonoids of Echinps latifolius suppress Wnt signaling in adjuvant arthritis rats]

The role of flavonoids of Echinps latifolius (FELT) in Wnt signaling was investigated in adjuvant arthritis (AA) rats. The therapeutic effects of FELT on AA rats were detected by rat arthritis score and MTT. The effect of FELT gavage treatment on the Wnt signaling key gene β-catenin, C-myc and cyclin D1 in synovium from AA rats was detected by Real-time qPCR, and the effects of FELT gavage treatment on the upstream negative regulation gene SFRP 1,2,4,5 in synovium from AA rats were detected by Real-time qPCR. The results showed that FELT gavage treatment significantly inhibited arthritis score and MTT values in AA rats, significantly inhibited the expression of the Wnt signaling gene β-catenin, C-myc and cyclin D1, significantly up-regulated the expression of the up- stream negative regulation gene SFRP 1,2,4. FELT has a better therapeutic effect for AA rats.

Etanercept increases tumor necrosis factor-alpha level but not sFas level in patients with rheumatoid arthritis

BACKGROUND

Targeted anti-tumor necrosis factor-alpha (TNFα) therapy in patients with rheumatoid arthritis (RA) has resulted in dramatic improvement in the disease course and prognosis. One of the features of RA is hyperplasia of synovial cells, particularly RA synovial fibroblasts (RA-SF), caused partially by impaired apoptosis of RA-SF cells. It has been shown that TNFα may inhibit apoptosis in RA-SF cells and this process may be reversed by the use of TNFα antagonists.

OBJECTIVES

To determine the influence of etanercept, an anti-TNFα agent, on sFas (CD 95) receptor.

METHODS

We analyzed serum levels of sFaS and TNFα in a group of 26 patients with high RA disease activity who were selected to start treatment with etanercept. Assessment of sFas receptor and TNFα levels was performed before and 6 months after treatment with etanercept.

RESULTS

Treatment with etanercept resulted in increased TNFα levels (log TNFα 0.602 vs. 1.17, P < 0.05) but no change in sFas levels (log sFas 3.17 vs. 3.11, P = 0.37). As expected, treatment resulted in significant reduction in both disease activity and levels of inflammatory markers.

CONCLUSIONS

Etanercept may increase TNFα levels in patients with RA. We also speculate that the Fas pathway is not the main apoptotic pathway in patients with RA treated with etenercept, since sFas, a marker of apoptotic activity, remained unchanged and was not influenced by disease activity and concomitant treatment.

Methotrexate-mediated inhibition of nuclear factor κB activation by distinct pathways in T cells and fibroblast-like synoviocytes

OBJECTIVES

Nuclear factor κB (NF-κB) is a critical activator of inflammatory processes and MTX is one of the most commonly prescribed DMARDs for treatment of RA. We sought to determine whether MTX inhibited NF-κB activity in RA and in lymphocytes and fibroblast-like synoviocytes (FLSs) and to define underlying mechanisms of action.

METHODS

An NF-κB luciferase reporter plasmid was used to measure NF-κB activation across experimental stimuli. Flow cytometry was used to quantify changes in intracellular protein levels, measure levels of reactive oxygen species and determine apoptosis. Quantitative RT-PCR was used to identify changes in MTX target genes.

RESULTS

In T cell lines, MTX (0.1 μM) inhibited activation of NF-κB via depletion of tetrahydrobiopterin (BH4) and increased Jun-N-terminal kinase (JNK)-dependent p53 activity. Inhibitors of BH4 activity or synthesis also inhibited NF-κB activation and, similar to MTX, increased JNK, p53, p21 and JUN activity. Patients with RA expressed increased levels of phosphorylated or active RelA (p65) compared with controls. Levels of phosphorylated RelA were reduced in patients receiving low-dose MTX therapy. In contrast, inhibition of NF-κB activation by MTX was not mediated via BH4 depletion and JNK activation in FLSs, but rather was completely prevented by adenosine receptor antagonists.

CONCLUSION

Our findings support a model whereby distinct pathways are activated by MTX in T cells and FLSs to inhibit NF-κB activation.

[Pulchinenoside control MeCP2 expression in FLS from RA model rats]

The role of pulchinenoside (PULC) in the regulation of MeCP2 expression was investigated in RA model rats. Adjuvant arthritis rats were used as RA model rats, and fibroblast-like synoviocytes (FLS) from the RA model rats were cultured. The effect of 100 mg x kg(-1) PULC gavage treatment on the MeCP2 expression and the effect of MeCP2 siRNA on the expression of SFRP2 and β-catenin were detected by real time qPCR and Western blotting. The role of PULC in the FLS proliferation was detected by MTT. The results showed that the MeCP2 expression was down-regulated, the SFRP2 expression was up-regulated and the FLS proliferation was inhibited in FLS after therapy. MeCP2 siRNA significantly inhibited the MeCP2 expression, up-regulated the SFRP2 expression and inhibited the β-catenin expression in FLS from RA model rats. PULC may increase the SFRP2 expression, inhibit the Wnt signaling and inhibit the FLS proliferation in FLS from the RA model rats by inhibiting the MeCP2 expression.

Targeting the P2X7 receptor in rheumatoid arthritis: biological rationale for P2X7 antagonism

OBJECTIVES

This paper aims to explore the functional significance of the P2X7 receptor in preclinical models of rheumatoid arthritis.

METHODS

Preclinical studies in vivo were performed using the rat streptococcal cell wall (SCW) arthritis model. Ex vivo cultures of lipopolysaccharide (LPS)/benzoylbenzoyl adenosine triphosphate (BzATP)-stimulated human monocytes were generated to test the activities of a novel, highly specific inhibitor of human P2X7, AZD9056, on interleukin (IL)-1 and IL-18 release.

RESULTS

P2X7 receptor expression was detected in inflamed synovial tissue after onset of SCW-induced arthritis in rats. Inhibition of P2X7 therein led to reduced articular inflammation and erosive progression. No effect was noted on acute-phase responses. Ex vivo, AZD9056 inhibited IL-1 and IL-18 release to BzATP in LPS-primed human monocytes.

CONCLUSIONS

P2X7 receptor inhibition could represent a novel approach to the treatment of inflammatory arthritis. However, confirmatory clinical studies are warranted to further explore this possibility.

Dynamic contrast-enhanced, extremity-dedicated MRI identifies synovitis changes in the follow-up of rheumatoid arthritis patients treated with rituximab

OBJECTIVES

The aim of this study is to assess prospectively the effect of rituximab (RTX) on MRI features of wrist joint disease in patients affected by rheumatoid arthritis (RA).

METHODS

Ten patients (6F/4M, mean age 52.9±15.5 years) diagnosed with IgM rheumatoid factor, anti-CCP positive, RA according to the 1987 ACR criteria were treated with a single course of RTX (2 infusions of 1000 mg, 15 days apart). MRI of the dominant hand was performed with a 0.2T extremity-dedicated machine using pre and post contrast T1 weighted SE, turbo 3D, and STIR sequences at baseline, and after 4 and 24 weeks. MRI was analysed using the OMERACT-RAMRIS score and the dynamic contrast-enhanced (DCE-MRI) technique for wrist synovitis, which calculates the enhancement ratio as both rate of early enhancement (REE) and relative enhancement (RE). The corresponding ME and IRE parameters were calculated also through a computer-aided semi-automated method on the mean of three MRI slices and on a small ROI positioned in the area of maximum enhancement.

RESULTS

DAS significantly decreased during the study period (ANOVA for repeated measures, p=0.005). The RAMRIS score did not change along the study, whereas the dynamic MRI values RE, IRE and ME on the small ROI significantly decreased. RE, but not the RAMRIS synovitis score, significantly correlated with DAS at baseline, 1 and 6 months (p=0.005, 0.04, and 0.0007, respectively).

CONCLUSIONS

RTX confirmed good clinical efficacy, which was paralleled by a significant decrease in dynamic MRI results for wrist synovitis. On the contrary, the traditional RAMRIS measures did not change.

Estradiol-potentiated cadherin-11 in synovial membrane involves in temporomandibular joint inflammation in rats

Estrogen is involved in inflammation/pain of temporomandibular joint (TMJ), but the underlying mechanisms are largely unknown. Cadherin-11 plays an essential role in synovial inflammation. This study examined whether estrogen could potentiate cadherin-11 in synoviocytes and contribute to TMJ inflammatory pain. Female rats were ovariectomized, treated with increasing doses of 17β-estradiol for 10 days, and injected intra-articularly with complete Freund's adjuvant to induce TMJ inflammation. The expression of cadherin-11 in synovial membrane was evaluated. TMJ pain was blocked with intra-articular injection of anti-cadherin-11 antibody and evaluated by head withdrawal threshold. Primary TMJ synoviocytes were treated with estradiol and tumor necrosis factor (TNF)-α or blocked with anti-cadherin-11 antibody to assess the expression of cadherin-11, interleukin (IL)-6, cyclooxygenase 2 (COX-2), and inducible nitric oxide synthase (iNOS). We observed that estradiol potentiated the inflammation-induced expression of cadherin-11 in the synoviocytes of synovial membrane from inflamed TMJ. Estradiol induced cadherin-11 expression in a dose- and time-dependent manner in primary synoviocytes and further potentiated the induction of cadherin-11 by TNF-α in synoviocytes. Furthermore, an estrogen receptor antagonist or a NF-κB inhibitor partially blocked the effects of estradiol on cadherin-11 induction in the synovial membrane. Blocking cadherin-11 partially reversed the TMJ inflammatory pain and estradiol-potentiated proliferation of synovial lining cells accompanied with iNOS expression. In addition, blocking cadherin-11 reversed TNF-α-induced and estradiol-potentiated transcription of IL-6, COX-2, and iNOS in primary synoviocytes. These results suggest that estrogen aggravated TMJ inflammatory pain partially through cadherin-11-mediated release of proinflammatory cytokines and enzymes in the synoviocytes.

Inhibited osteoclastic bone resorption through alendronate treatment in rats reduces severe osteoarthritis progression

Osteoarthritis (OA) is a non-rheumatoid joint disease characterized by progressive degeneration of extra-cellular cartilage matrix (ECM), enhanced subchondral bone remodeling, osteophyte formation and synovial thickening. Alendronate (ALN) is a potent inhibitor of osteoclastic bone resorption and results in reduced bone remodeling. This study investigated the effects of pre-emptive use of ALN on OA related osteoclastic subchondral bone resorption in an in vivo rat model for severe OA. Using multi-modality imaging we measured effects of ALN treatment within cartilage and synovium. Severe osteoarthritis was induced in left rat knees using papain injections in combination with a moderate running protocol. Twenty rats were treated with subcutaneous ALN injections and compared to twenty untreated controls. Animals were longitudinally monitored for 12weeks with in vivo μCT to measure subchondral bone changes and SPECT/CT to determine synovial macrophage activation using a folate-based radiotracer. Articular cartilage was analyzed at 6 and 12weeks with ex vivo contrast enhanced μCT and histology to measure sulfated-glycosaminoglycan (sGAG) content and cartilage thickness. ALN treatment successfully inhibited subchondral bone remodeling. As a result we found less subchondral plate porosity and reduced osteophytosis. ALN treatment did not reduce subchondral sclerosis. However, after the OA induction phase, ALN treatment protected cartilage ECM from degradation and reduced synovial macrophage activation. Surprisingly, ALN treatment also improved sGAG content of tibia cartilage in healthy joints. Our data was consistent with the hypothesis that osteoclastic bone resorption might play an important role in OA and may be a driving force for progression of the disease. However, our study suggest that this effect might not solely be effects on osteoclastic activity, since ALN treatment also influenced macrophage functioning. Additionally, ALN treatment and physical activity exercised a positive effect in healthy control joints, which increased cartilage sGAG content. More research on this topic might lead to novel insights as to improve cartilage quality.

Hempseed oil induces reactive oxygen species- and C/EBP homologous protein-mediated apoptosis in MH7A human rheumatoid arthritis fibroblast-like synovial cells

ETHNOPHARMACOLOGICAL RELEVANCE

The medicinal efficacy of hempseed (Cannabis sativa L.), which is rich in polyunsaturated fatty acids, in atopic dermatitis, inflammation, and rheumatoid arthritis (RA) has been suggested for centuries. Hempseed has been used as a treatment for these diseases in Korean and Chinese folk medicine. The aim of the study is to investigate the effects of hempseed oil (HO) on MH7A human RA fibroblast-like synovial cells.

MATERIALS AND METHODS

MH7A cells were used to study the anti-rheumatoid effects of hempseed (Cannabis sativa L., cv. Cheungsam/Cannabaceae) oil by investigating cell viability, apoptosis, lipid accumulation, oxidative stress, and endoplasmic reticulum (ER) stress-induced apoptosis.

RESULTS

HO treatment reduced the survival rate of MH7A cells and promoted apoptotic cell death in a time- and dose-dependent manner. Both lipid accumulation and the level of intracellular reactive oxygen species (ROS) increased in HO-treated MH7A cells. Co-treatment with the antioxidant Tiron effectively abrogated the cytotoxic effects of HO; the ROS level was reduced, cell viability was recovered, and apoptotic cell death was significantly diminished. Moreover, HO-treated cells exhibited increased expression of the major ER stress markers, glucose-regulated protein 78 and C/EBP homologous protein (CHOP). The siRNA-mediated knockdown of CHOP prevented HO-induced apoptosis.

CONCLUSIONS

Our results suggest that HO treatment induced lipid accumulation, ROS production, CHOP expression, and apoptosis in MH7A cells, and that CHOP functions as an anti-rheumatoid factor downstream of HO in MH7A cells.

Detection of synovitis by ultrasonography in clinically inactive juvenile idiopathic arthritis on and off medication

OBJECTIVES

To determine the prevalence of abnormalities detected by ultrasonography (US) in children with juvenile idiopathic arthritis (JIA) showing clinically inactive disease (ID) on medication and off medication.

INCLUSION CRITERIA

1) JIA patients, 2) clinician-determined ID, 3) JIA drugs withdrawal or stably dosed modified anti-rheumatic drugs (DMARDs) therapy for at least 6 months prior to inclusion, 4) biologics naïve patients. Clinical and US assessments were performed on 44 joints, which were scored for grey-scale (GS) synovitis and Power Doppler (PD) signal. PD signal inside intra-articular synovium or tendon sheath was considered as inflammatory activity.

RESULTS

Thirty-four patients were included, of whom 23 patients were labelled as ID on medication and 11 patients without medication. The duration of the current episode of ID at the inclusion time was 9.5 months. Although it was longer for the group off medication there was no significant difference between the two groups (p=0.06). Thirteen patients presented US findings. Number of US-detected synovial abnormalities was higher in patients on medication, but there were no significant differences between both groups in the detection of GS synovitis (p=0.86), GS tenosynovitis (p=0.78) and PD signal (p=0.38). Out of 37 joints presenting US-determined GS-synovitis, 18 joints showed PD signal.

CONCLUSIONS

Our study provides evidence of synovitis and tenosynovitis on B-mode US in JIA patients with clinical inactivity. In addition, inflammatory activity upheld by power-Doppler has been shown in a few joints from patients on medication.

Hyaluronate-gold nanoparticle/tocilizumab complex for the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory immune disease causing the inflammation of synovial membrane and the articular cartilage destruction. In this work, hyaluronate-gold nanoparticle/Tocilizumab (HA-AuNP/TCZ) complex was prepared for the treatment of RA. AuNP was used as a drug carrier with antiangiogenic effect. TCZ is a humanized monoclonal antibody against the interleukin-6 (IL-6) receptor and used as an immunosuppressive drug by interfering IL-6 in the pathogenesis of RA. HA is known to have cartilage-protective and lubricant effects. HA was modified with cystamine via reductive amination, which was reduced with dithiothreitol (DTT) to prepare end-group thiolated HA (HA-SH). AuNP was chemically modified with HA-SH and physically modified with TCZ. The formation of HA-AuNP/TCZ complex was corroborated by UV-vis spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). The therapeutic effect of HA-AuNP/TCZ complex on RA was confirmed in collagen-induced arthritis (CIA) model mice by ELISA, histological, and Western blot analyses.

Therapeutic effects of standardized Vitex negundo seeds extract on complete Freund's adjuvant induced arthritis in rats

The seeds of Vitex negundo L. (Verbenaceae) have been commonly used as a folk remedy for the treatment of rheumatism and joint inflammation in Traditional Chinese Medicine. This study aimed to evaluate the anti-arthritic activity of the extract of V. negundo seeds (EVNS) using Freund's complete adjuvant (CFA) induced arthritis (AA) in rat model. As a result, EVNS, with abundant phenylnaphthalene-type lignans, significantly inhibited the paw edema, decreased the arthritis score and spleen index, and reversed the weight loss of CFA-injected rats. Histopathological studies showed a marked decrease of synovial inflammatory infiltration and synovial lining hyperplasia in the joints of EVNS-treated animals. The remarkable decrement of serum inflammatory factors (TNF-α, IL-1β and IL-6) were observed in EVNS-treated rats, whereas, IL-10, an anti-inflammatory cytokine, was found to be significantly increased by EVNS. The expressions of COX-2 and 5-LOX in PBMC were also inhibited by administration of EVNS. Our results demonstrated that V. negundo seeds possessed potential therapeutic effect on adjuvant induced arthritis in rats by decreasing the levels of TNF-α, IL-1β and IL-6 and increasing that of IL-10 in serum as well as down-regulating the levels of COX-2 and 5-LOX, and therefore may be an effective cure for the treatment of human rheumatoid arthritis.

Growth factor priming differentially modulates components of the extracellular matrix proteome in chondrocytes and synovium-derived stem cells

To make progress in cartilage repair it is essential to optimize protocols for two-dimensional cell expansion. Chondrocytes and SDSCs are promising cell sources for cartilage repair. We previously observed that priming with a specific growth factor cocktail (1 ng/mL transforming growth factor-β1, 5 ng/mL basic fibroblast growth factor, and 10 ng/mL platelet-derived growth factor-BB) in two-dimensional culture, led to significant improvement in mechanical and biochemical properties of synovium-derived stem cell (SDSC)-seeded constructs. The current study assessed the effect of growth factor priming on the proteome of canine chondrocytes and SDSCs. In particular, growth factor priming modulated the proteins associated with the extracellular matrix in two-dimensional cultures of chondrocytes and SDSCs, inducing a partial dedifferentiation of chondrocytes (most proteins associated with cartilage were down-regulated in primed chondrocytes) and a partial differentiation of SDSCs (some collagen-related proteins were up-regulated in primed SDSCs). However, when chondrocytes and SDSCs were grown in pellet culture, growth factor-primed cells maintained their chondrogenic potential with respect to glycosaminoglycan and collagen production. In conclusion, the strength of the label-free proteomics technique is that it allows for the determination of changes in components of the extracellular matrix proteome in chondrocytes and SDSCs in response to growth factor priming, which could help in future tissue engineering strategies.

Targeting fibroblast-like synovial cells at sites of inflammation with peptide targeted liposomes results in inhibition of experimental arthritis

In this study we examined a synovium-specific targeted liposomal drug delivery system for its ability to localize and release its drug cargo to inflamed joints. Targeted liposomes were tested in vitro for binding to synovial fibroblast like (FLS) and endothelial cells using flow cytometry and in vivo for localization to joints using a rat model of adjuvant induced arthritis (AIA). Targeted liposomes were then loaded with anti-arthritic medications and examined for clinical efficacy in AIA. Targeted liposomes specifically bound to rabbit FLS and human FLS and showed a 7-10 fold increase in vivo localization in affected joints compared to unaffected joints. Histological sections from rats treated with prednisone and a new immunosuppressive peptide CP showed minimal inflammation. This report substantiates the ability of the novel FLS sequence to target liposomal drug delivery and offers an alternative therapeutic approach for the treatment of arthritis.

TLR dependent XBP-1 activation induces an autocrine loop in rheumatoid arthritis synoviocytes

X-box binding protein 1 (XBP1) is a central regulator of the endoplasmic reticulum (ER) stress response. It is induced via activation of the IRE1 stress sensor as part of the unfolded protein response (UPR) and has been implicated in several diseases processes. XBP1 can also be activated in direct response to Toll-like receptor (TLR) ligation independently of the UPR but the pathogenic significance of this mode of XBP1 activation is not well understood. Here we show that TLR-dependent XBP1 activation is operative in the synovial fibroblasts (SF) of patients with active rheumatoid arthritis (RA). We investigated the expression of ER stress response genes in patients with active RA and also in patients in remission. The active (spliced) form of (s)XBP1 was significantly overexpressed in the active RA group compared to healthy controls and patients in remission. Paradoxically, expression of nine other ER stress response genes was reduced in active RA compared to patients in remission, suggestive of a UPR-independent process. However, sXBP1 was induced in SF by TLR4 and TLR2 stimulation, resulting in sXBP1-dependent interleukin-6 and tumour necrosis factor (TNF) production.

We also show that TNF itself induces sXBP1 in SF, thus generating a potential feedback loop for sustained SF activation. These data confirm the first link between TLR-dependent XBP1 activation and human inflammatory disease. sXBP1 appears to play a central role in this process by providing a convergence point for two different stimuli to maintain activation of SF.

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sXBP1 is upregulated in PBMC from patients with active RA.

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TLR2 and TLR4 mediated sXBP1 activation in synovial fibroblasts.

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SNAPIN-induced cytokine production is dependent on sXBP1.

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Proinflammatory cytokines cause XBP1 activation in synovial fibroblasts.

Deoxycytidine kinase promotes the migration and invasion of fibroblast-like synoviocytes from rheumatoid arthritis patients

Rheumatoid arthritis (RA) is a complex, multi-system disease whose primary site of inflammatory tissue damage is the joint. The increasing evidences indicate that activated RA fibroblast-like synoviocytes (FLS) play a critical role in the development of pannus by migrating into cartilage and bone. Furthermore FLS and T cells can activate each other in vitro and in vivo, which is crucial for the progress of RA. Deoxycytidine kinase (DCK) has been linked to peripheral T cell homeostatic proliferation and survival, which is very important for RA. Yet, the function of DCK in FLS is still unknown. Here, we present a story that DCK could regulate the migration and invasion of FLS through AKT pathway in RA patients. Moreover, DCK seems to be the upstream of AKT and FAK, and AKT inhibitor exerted the similar effect on FLS motility. In summary, our study characterized the new role of DCK in human primary FLS cells, and figured out the possible pathway DCK involved in, and these findings might propose DCK as a novel target for controlling joint destruction of RA.

The role of Act1, a NF-κB-activating protein, in IL-6 and IL-8 levels induced by IL-17 stimulation in SW982 cells

CONTEXT

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic inflammation in the synovial membrane of affected joints. It has been shown that several kinds of cytokine were increased in synovial fluid, while the underlying mechanism remains poorly understood.

OBJECTIVES

NF-κB activator 1 (Act1) is a recently identified protein binding to the IκB kinase complex. Our study aimed to investigate the expression of Act1 induced by cytokine IL-17 stimulation in SW982 cells.

MATERIALS AND METHODS

The human synovial sarcoma cell line SW982 and primary cultured RA fibroblast-like synovial cells were used. RT-PCR and Western blot assays were selected to investigate the genetic and protein expression of Act1. Additionally, four independent Act1 small interfering RNA (siRNA) oligonucleotides were designed and obtained according to the GenBank cDNA, the sequence of Act1 (Traf3ip2). Finally, enzyme-linked immunosorbent assay (ELISA) double antibody sandwich was used to assay supernatant IL-6 and IL-8 concentrations.

RESULTS

The Act1 mRNA expression level increased significantly after stimulation with IL-17 (5-100 ng/ml) in SW982 cells. Additionally, the level of Act1 mRNA expression correlated positively with the concentration of IL-17 (p < 0.01). IL-17 induced IL-6 and IL-8 in SW982 cells was in a concentration- and time-dependent way. Furthermore, ELISA assay revealed that IL-17 (20 ng/ml) significantly increased IL-6 (1927.4 ± 288.77 versus 786.5 ± 172.42 ng/ml, p < 0.01) and IL-8 levels (984.8 ± 95.09 ng/ml versus 307.1 ± 90.83 ng/ml, p < 0.01) compared with control group after stimulation for 24 h. However, transfection of Traf3ip2 siRNA markedly decreased IL-6 (995.9 ± 115.30 ng/ml versus 1816.1 ± 273.27 ng/ml, p < 0.01) and IL-8 levels (575.6 ± 65.96 ng/ml versus 929.4 ± 124.39 ng/ml, p < 0.01) compared to transfection negative control. These findings suggested that IL-6 and IL-8 level induced by IL-17 in SW982 cells could be reversed by down-regulation of Act1 expression level with Traf3ip2 siRNA.

CONCLUSION

Our results suggested that Act1 might play a key role in the pathophysiology and the treatment of RA.

Importance of synovitis in osteoarthritis: evidence for the use of glycosaminoglycans against synovial inflammation

OBJECTIVES

After detailing the different aspects of synovial inflammation (i.e., cellular, biochemical, and vascular) and based on the current knowledge, the aim of this review was to collect the available in vitro and in vivo data regarding the potency of some glycosaminoglycan (GAG) compounds to target synovial inflammation, an important aspect of osteoarthritis.

METHODS

The first part of the review corresponds to a qualitative review of the inflammatory status of OA synovial membrane. The second part corresponds to a systematic review of the literature regarding the potential effects of some GAGs on the previously described phenomenon.

RESULTS

The synovial aspect of the inflammatory status of OA has been detailed. Chondroitin sulfate has demonstrated to control the three aspects of synovial membrane inflammation: cell infiltration and activity, biochemical mediators release, and angiogenesis. Glucosamine is also active on both cellular and molecular aspects of the inflammatory reaction. Hyaluronic acid seems to be anti-inflammatory in its native form, while products of degradation are reported to be pro-angiogenic.

CONCLUSION

Much evidence suggests that some of the studied GAG compounds could target different aspects of synovitis. Some of them could be considered in combination therapy since they exhibit complementary properties. Most of the studies have concentrated on articular cartilage and chondrocytes. In order to achieve a structure modification, one may now consider all joint tissues and investigate the drug potency on all of them. Potent treatment should trigger the most important features of OA: cartilage degradation, subchondral bone sclerosis, and all aspects of synovial inflammation.

[Regulatory roles of compound danshen in the downstream path of cyclooxygenases in rheumatoid arthritis patients' synovium]

Rheumatoid arthritis (RA) belongs to Bi syndrome (arthralgia) in Chinese medicine. Till now there lacks effective therapeutic methods. Recently cyclooxygenases (COXs) inhibitors, having regulator roles for many pro-inflammatory cytokines, have been widely used in RA treatment. But due to existing cardiovascular risks, researches on targeting the downstream specific factors of COXs have been under discussion. Considering the key role of blood stasis syndrome (BSS) in the pathology of RA and the fact that thromboxane A2 (TXA2) plays a pivotal role in BSS, we theoretically explored possible regulatory roles of Compound Danshen, a representative therapy in blood activating stasis removing method in the downstream path of COXs in synovial cells of RA. We proposed a brand new research direction of RA researches.

[Effect of sanshui baihu decoction on the proliferation of fibroblast-like synoviocytes and its secretion of IL-6 and IL-17]

OBJECTIVE

To observe the effect of Sanshui Baihu Decoction (SBD) containing serum on the proliferation of in vitro cultured fibroblast-like synoviocytes (FLS) derived from rheumatoid arthritis (RA) and osteoarthritis (OA) and its secretion of interleukin-6 (IL-6) and IL-17, and to explore the pharmacological mechanism of SBD.

METHODS

The FLS obtained from cultured RA and OA patients' synovial tissue were cultured and passaged in vitro in a routine way. The cultured medium was changed to DMEM with 20% SBD containing serum and cultured for 72 h after cultured for 3 to 6 generations. The proliferation rate of FLS was detected by MTT assay. Levels of IL-6 and IL-17 in the supernatant were detected by ELISA. Leflunomide and saline containing serum were used as positive and negative control respectively.

RESULTS

SBD containing serum significantly inhibited the proliferation of RA-FLS and OA-FLS, and decreased the secretion of IL-17 in RA-FLS. Its inhibition efficiency of SBD was equivalent to that of Leflunomide. No obvious inhibition on the secretion of IL-6 in RA-FLS was observed. It had no significant effect on the secretion of IL-17 and IL-6 in OA-FLS.

CONCLUSION

SBD could inhibit the proliferation of FLS and the secretion of IL-17 in RA-FLS, which might be one of its pharmacological mechanisms for treating RA.

Pressure and inflammatory stimulation induced increase of cadherin-11 is mediated by PI3K/Akt pathway in synovial fibroblasts from temporomandibular joint

OBJECTIVE

The goal of the study was to investigate the expression of cadherin-11 in synovial fibroblasts (SFs) under mechanical or inflammatory stimuli, and its potential relationship with PI3K/Akt signaling pathway.

METHODS

SFs separated from rat temporomandibular joint (TMJ) were treated with hydrostatic pressures (HP) of 30, 60, 90, and 120 kPa, as well as tumor necrosis factor-α (TNF-α) for 12, 24, 48, and 72 h. The location of cadherin-11 was observed by immunofluorescence microscopy, and its expression was detected by real-time PCR and Western blot. We also studied the activation of PI3K/Akt signaling pathway in SFs with HP or TNF-α stimulation.

RESULTS

The results showed that increased expression of cadherin-11 could be found in the cell-cell contact site of SFs in response to HP and inflammatory stimulation. The mRNA and protein expression of cadherin-11 was positively correlated with the intensity of HP and the duration time of TNF-α treatment. Increased expression of vascular endothelial growth factor-D (VEGF-D) and activation of Akt were also found. Treatment with PI3K inhibitor LY294002 attenuated the pressure or inflammatory cytokine induction increases of cadherin-11, VEGF-D, and FGF-2 both in mRNA and protein levels.

CONCLUSIONS

These findings suggest that cadherin-11 may play important roles in SFs following exposure to mechanical loading and inflammatory stimulation. In addition, PI3K/Akt pathway was associated with pressure or inflammation-induced cadherin-11 expression, which may involve in the pathogenesis of temporomandibular diseases.

Effect of qubi zhentong recipe on synovial gene expression in collagen-induced arthritis in rats

OBJECTIVE

To investigate the effect of the Chinese medical formula Qubi Zhentong Recipe(, QZR) on the synovial gene expression profile in collagen-induced arthritis (CIA) rats.

METHODS

Ten rats were randomly chosen from 60 rats as the control group, and the other 50 rats were used for the CIA models. The CIA model group was constructed by bovine injection of type II collagen through the rats' neck and tail. Twenty rats were randomly chosen from 34 successful CIA models and randomly assigned into two groups: the model group (n =10) and the QZR group (n=10). The QZR group was fed intragastrically with QZR 22.9 g/(kg·d) (10 times the clinical adult dose), and the CIA model group was given the same dose of normal saline. Both model and QZR groups were administered treatment once a day. Total RNA was collected from the knee joint synovium after 30 days. The change in gene expression profile was analyzed by a whole gene chip.

RESULTS

A total of 76 genes showed a difference in expression between CIA model group and the control group; 35 genes were down-regulated and 41 were up-regulated. A total of 67 genes showed a difference in expression between the model group and the QZR group; 48 genes were down-regulated and 19 were upregulated.

CONCLUSIONS

QZR may affect CIA by stimulating multiple genes and targets, which are related to oncogenes, apoptosis, metabolism, the immune system, ion channels, and transport proteins.

Isolation of xanthone and benzophenone derivatives from Cyclopia genistoides (L.) Vent. (honeybush) and their pro-apoptotic activity on synoviocytes from patients with rheumatoid arthritis

A fast and efficient method for the isolation of the C-glucosidated xanthones mangiferin and isomangiferin from the South-African plant Cyclopia genistoides was developed for the first time. The procedure involved extraction, liquid-liquid partitioning with ethyl acetate and subsequent precipitation of mangiferin and isomangiferin from methanol and acetonitrile-water fractions, respectively. Additionally, two benzophenone derivatives: 3-C-β-glucosides of maclurin and iriflophenone, were isolated from C. genistoides extracts using semi-preparative HPLC. Apart from the above, the isolation procedure also yielded hesperidin and small amounts of luteolin. The structures of the compounds were determined by 1D and 2D NMR experiments and/or LC-DAD-ESI-MS. The selected Cyclopia constituents were screened for pro-apoptotic activity on TNF-α-stimulated synovial cells isolated from rheumatoid arthritis patients. The strongest effect, measured as percent of apoptotic cells, was recorded for isomangiferin (75%), followed by iriflophenone 3-C-β-glucoside (71%), hesperidin (67%) and mangiferin (65%). The results are encouraging for further studies on the use of the above compounds in the treatment of rheumatoid arthritis.

The influence of resveratrol on the synovial expression of matrix metalloproteinases and receptor activator of NF-kappaB ligand in rheumatoid arthritis fibroblast-like synoviocytes

Medication of rheumatoid arthritis (RA) remains challenging and often controversial concerning side effects or long-term complications. We investigated the effect of resveratrol, a phytoalexin discussed for its chondro-protective and anti-inflammatory qualities, on the synovial expression of matrix-degrading enzymes like matrix metalloproteinases (MMPs) and bone-remodelling proteins in RA fibroblast-like synoviocytes (FLS). Interleukin-1beta-stimulated RA-FLS were treated with 100 microM resveratrol for 24 h. To evaluate the effect of resveratrol on the amount of bound/combined MMPs, a Luminex xMAP multiplexing technology was used. The alteration in expression of receptor activator of nuclear factor-kappaB ligand (RANKL) and osteoprotegrin (OPG) was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Resveratrol reduced the expression of MMP-1 (p = 0.022), MMP-3 (p = 0.021), and MMP-9 (p = 0.047). qRT-PCR showed a significant reduction in the relative abundance of the transcripts of OPG (p = 0.012) and RANKL (p = 0.018). Our in vitro findings indicate that resveratrol could be a new target for further pharmacological studies in the field of RA. In the future it could play a role as a possible substitute or supplement to currently used drugs against RA to prevent cartilage matrix degradation and pathological bone resorption due to inhibition of MMPs and RANKL.

Effect of anatase TiO2 nanoparticles on the growth of RSC-364 rat synovial cell

Nanoscale materials (such as TiO2, hydroxyapatite nanoparticles) have gained much concern in the coating of implants for cell adhesion and growth to improve the osteoconductivity. However, due to attrition and corrosion, the wear particles would be generated from the joint in living organism, and influence the physiological function of synovial membranes in joint cavity. In this study, the potential cytotoxicity of anatase TiO2 nanoparticles (TiO2 NPs) on rat synovial cell line 364 (RSC-364) was investigated. After treatment with different concentrations of TiO2 NPs (0, 3, 30, 300 microg/ml), the viability of RSC-364 cells were decreased in a dose-dependent manner. TiO2 NPs exposure could disrupt the integrity of cell plasma membrane, leading to the increased leakage of lactate dehydrogenase (LDH) into the culture medium. TiO2 NPs were uptaken by RSC-364 cells. The ultrastructure of RSC-364 cells was changed such as nuclear shrinkage and mitochondrial swelling. The reactive oxygen species (ROS) was over-produced especially in the cells exposed to 30 and 300 microg/ml TiO2 NPs. The activities of endogeneous antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), were significantly decreased. The increased lipid peroxidation product (malondialdehyde, MDA) suggests the oxidative damage in cells. The flow cytometry detected that the cell cycle was blocked in G0/G1 phase, inhibiting the cell proliferation. These preliminary results indicate the oxidative stress injury and cytotoxicity of anatase TiO2 NPs on rat synovial cells. The reasonable and safe application of nanomaterials in artificial implants needs further study.

SeMet inhibits IL-1β-induced rheumatoid fibroblast-like synoviocytes proliferation and the production of inflammatory mediators

Previous studies demonstrated that Se has anti-inflammatory activities and that it plays an important role in maintaining normal cartilage metabolism. Nevertheless, little is known about the effects of Se on the production of inflammatory mediators in rheumatoid fibroblast-like synoviocytes (FLSs). The objective of this study was to determine the effects of Se on the interleukin-1β (IL-1β)-induced proliferation of FLSs and production of matrix metalloproteinases (MMPs) and inflammatory mediators by FLSs. In this study, the proliferation of FLSs was assessed using the MTT assay after cultured with/without the presence of IL-1β and SeMet. Human FLSs were pretreated with SeMet (0.5 μM) and subsequently stimulated with IL-1β (5 ng/ml) for 24 h. Production of NO and PGE2 were evaluated by the Griess reaction and ELISA. Gene expression of MMP-3, MMP-13, iNOS, and COX-2 was measured by real-time PCR. MMP-3 and MMP-13 proteins in culture medium were determined using cytokine-specific ELISA. Western immunoblotting was used to analyze the iNOS and COX-2 protein production in the culture medium and the activity of phosphorylation of P38 MAPK pathways. We found that SeMet significantly inhibits IL-1β-induced proliferation of FLSs. SeMet also inhibited the production of PGE2 and NO induced by IL-1β. SeMet significantly decreased IL-1β-stimulated gene expression and production of MMP-3, MMP-13, iNOS, and COX-2 in human FLSs. In addition, we found SeMet partly inhibited the IL-1β-induced activation of p38 MAPK pathways. The present report is first to demonstrate that SeMet inhibits IL-1β-induced expression of MMPs and production of inflammatory factors in cultured FLSs, indicating that SeMet may be a potential agent in the treatment of rheumatoid arthritis.

[Effect of pulchinenoside in regulating FLS SFRP2 expression of RA model rats]

OBJECTIVE

To study the effect of pulchinenoside (PULC) in modulating SFRP2 expression in fibroblast-like synoviocytes (FLS) of rheumatoid arthritis (RA) model rats.

METHOD

The effect of PULC in treating RA rats was evaluated by rat arthritis score and paw swelling score. The inhibitory effect of PULC on FLS proliferation was detected by MTT reagent. The effects of PULC gavage treatment in modulating gene expression of FLS SFRP2, critical gene beta-catenin of Wnt pathway and downstream effector genes C-myc of of Wnt pathway were detected by RT-PCR and Western blotting.

RESULT

PULC had a significant effect in treating RA rats and that SFRP2 expression was down-regulated in FLS. After PULC gavage treatment, FLS SFRP2 expression was obviously up-regulated, whereas beta-catenin and C-myc gene expressions were significantly down-regulated.

CONCLUSION

PULC can inhibit abnormal proliferation of synovial membrane by modulating Wnt pathway of RA rats.

[Effects of dioscornin tablet containing serum on NF-kappaB p65, STAT3, and VEGF mRNA expressions in rats' synovial cell strain RSC-364 induced by IL-17 and TNF-alpha]

OBJECTIVE

To observe the effects of Dioscornin Tablet (DT) containing serum on nuclear factor of kappa B (NF-kappaB) p65, signal transducer and activator of transcription 3 (STAT3), and vascular endothelial growth factor (VEGF) mRNA expressions in rats' synovial cell strain 364 (RSC-364) induced by interleukin-17 (IL-17) and tumor necrosis factor-alpha (TNF-alpha), and to investigate the underlying mechanisms for DT to inhibit angiogenesis of rheumatoid arthritis (RA).

METHODS

In this experiment, the vehicle control group, the cell model group, the DT containing serum group, and the positive control group (Tripterygium containing serum) were set up. The DT containing serum and the Tripterygium containing serum were prepared. The RA cell model was established by IL-17 combined TNF-alpha induced injury in RSC-364. The RA cells were intervened by DT containing serum and Tripterygium containing serum respectively. The DNA binding activity of NF-kappaB p65 was detected using TransAM NF-kappaB p65. The expression of STAT3 was observed using Western blot. The VEGF mRNA expressions were detected by real-time quantitative PCR.

RESULTS

Compared with the vehicle control group, the NF-kappaB p65 activity, the expressions of STAT3 and VEGF mRNA increased significantly in RSC-364 induced by IL-17 +TNF-alpha (P < 0.01, P < 0.05). Compared with the model group, the NF-kappaB p65 activity, the expressions of STAT3 and VEGF mRNA decreased significantly in the DT containing serum group and the positive control group (P < 0.01, P < 0.05). There was no statistical difference between the two groups (P > 0.05).

CONCLUSION

DT inhibited the VEGF mRNA expression through inhibiting the NF-kappaB p65 activity and the STAT3 protein expression in the Janus kinase (JAK)-signal transducer and activating transcription factor pathway, thus inhibiting the angiogenesis of RA.

[Effects of danshen injection on the proliferation of rheumatoid arthritis fibroblast-like synoviocytes cultured with human serum]

OBJECTIVE

To investigate the effects of Danshen Injection (DSI) on the proliferation of rheumatoid arthritis fibroblast-like synoviocytes (RA FLSs) cultured in RA patients' serum.

METHODS

The RA FLSs harvested from RA patients' synovial fluid were primarily cultured by routines. The cells were cultured with 10% inactivated human serum (the healthy human serum and the RA patients' serum) for 24 h. Then DSI at the final concentration of 0. 4 mg/mL was added in the cells for further 24 h culture. By taking 10% fetal calf serum as the control, the morphological changes were observed under optical microscope. The proliferation was analyzed by MTT. The apoptosis was detected by flow cytometry. The total RNA was extracted and reverse transcription was performed. The Bax mRNA expression was detected by fluorescent quantitative PCR.

RESULTS

(1) After human serum was added in the healthy human serum and RA patients' serum, cells could grow adhering to the wall. Compared with the fetal calf serum group (FCS), the cell density was higher in the healthy human serum group than in the fetal calf serum group, with no obvious morphological changes. (2) MTT results showed that, compared with the fetal calf serum group, the absorbance value (OD) obviously increased in the healthy human serum group and the RA patients' serum group, showing statistical difference (P <0.01). After adding DSI at the final concentration of 0.4 mg/mL, cells from different serums were inhibited to various degrees (with OD significantly decreased, P <0.05). The OD value significantly increased more in the healthy human serum group and the RA patients' serum group than in the fetal calf serum group, showing statistical difference (P <0.01). There was statistical difference between the healthy human serum group and the RA patients' serum group (P <0.01). (3) The apoptosis rate in the RA patients' serum group obviously decreased with statistical difference, when compared with the Salvia miltiorrhiza free fetal calf serum group (P >0. 01). The apoptosis rate in the fetal calf serum group and the RA patients' serum group significantly increased after adding 0.4 mg/mL Salvia miltiorrhiza, showing statistical difference when compared with the Salvia miltiorrhiza free fetal calf serum group and the Salvia miltiorrhiza free RA patients' serum group (P <0.05). The FLSs were effected by 0.4 mg/mL Salvia miltiorrhiza, the apoptosis rate significantly decreased in the healthy human serum group and the RA patients' serum group, showing statistical difference when compared with the fetal calf serum group (P <0. 05, P <0.01). (4) The expression of Bax gene significantly increased in the RA patients' serum group and the fetal calf serum group after action of 0.4 mg/mL Salvia miltiorrhiza, showing statistical difference (P <0. 01). When 0.4 mg/mL Salvia miltiorrhiza was added, the expression of Bax mRNA obviously increased in the healthy human serum group and the RA patients' serum group, showing statistical difference when compared with the fetal calf serum group (P <0.01).

CONCLUSIONS

(1) Although healthy human serum can be favorable to the growth of RA FLSs, the fetal calf serum could reflect the actual results better in the cyto biological research on specific diseases (if there is no serum from patients with corresponding disease). (2) DSI could inhibit the proliferation of RA FLSs through promoting their apoptosis.

Quercetin: a potential natural drug for adjuvant treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is the rheumatism mainly manifested as disabling joint disease and mainly involves hands, wrists, feet and other small joints. Recurrent arthritis attacks, synovial cell hypertrophy and hyperplasia and bone and cartilage damages eventually lead to joint dysfunction and other complications, and there is no cure. Quercetin (QU) is a kind of natural flavonoids, with lipid-lowering, anti-inflammatory and other pharmacological activities, and minor toxic side effects. Thus, we assume that QU may be an adjuvant natural drug for treatment of RA. The possible mechanism is through regulation of NF-κB, to inhibit the transcription of joint synovitis factors, hinder the generation of inflammatory factors, and inhibit the inflammatory reaction; through inhibiting the activities of VEGF, bFGF, MMP-2 and other cytokines, to inhibit angiogenesis in multiple links and inhibit synovial pannus formation. QU may be an adjuvant natural drug for treatment of RA.

Symptom and structure modification in osteoarthritis with pharmaceutical-grade chondroitin sulfate: what's the evidence?

OBJECTIVES

Osteoarthritis is a chronic disease characterized by irreversible damage to joint structures, including loss of articular cartilage, osteophyte formation, alterations in the subchondral bone and synovial inflammation. It has been shown that chondroitin sulfate interferes with the progression of structural changes in joint tissues and is used in the management of patients with osteoarthritis.

METHODS

This review summarizes data from relevant reports describing the mechanisms of action of chondroitin sulfate that may explain the beneficial effects of the drug and examines the evidence for clinical efficacy of oral chondroitin sulfate in osteoarthritis. Data included in the review were derived from a literature search in PubMed. Literature searches were performed in PubMed using the search terms 'chondroitin sulfate', 'pharmaceutical-grade', 'osteoarthritis', 'randomized clinical trials', 'humans'. The MEDLINE database was searched from January 1996 through August 2012 for all randomized controlled trials, meta-analyses, systematic reviews, and review articles of chondroitin sulfate in osteoarthritis.

RESULTS

Chondroitin sulfate exerts in vitro a beneficial effect on the metabolism of different cell lines: chondrocytes, synoviocytes and cells from subchondral bone, all involved in osteoarthritis. It increases type II collagen and proteoglycan synthesis in human articular chondrocytes and is able to reduce the production of some pro-inflammatory factors and proteases, to reduce the cellular death process, and improve the anabolic/catabolic balance of the extracellular cartilage matrix (ECM). Clinical trials have reported a beneficial effect of chondroitin sulfate on pain and function. The structure-modifying effects of chondroitin sulfate have been reported and analyzed in recent meta-analyses. The results in knee osteoarthritis demonstrate a small but significant reduction in the rate of decline in joint space width. Because chondroitin sulfate quality of several nutraceuticals has been found to be poor, it is recommended that pharmaceutical-grade chondroitin sulfate is used rather than food supplements in the treatment of OA. Chondroitin sulfate is recommended by several guidelines from international societies in the management of knee and hip OA. Furthermore, its safety profile is favorable when compared with many other therapies used in OA.

CONCLUSION

Chondroitin sulfate is an effective and safe treatment option for patients with osteoarthritis.

Liposomal targeting of prednisolone phosphate to synovial lining macrophages during experimental arthritis inhibits M1 activation but does not favor M2 differentiation

Background

To determine the effects of liposomal targeting of prednisolone phosphate (Lip-PLP) to synovial lining macrophages on M1 and M2 polarization in vitro and during experimental arthritis.

Material and Methods

Experimental arthritis (antigen and immune complex induced) was elicited in mice and prednisolone containing liposomes were given systemically. Synovium was investigated using microarray analysis, RT-PCR and histology. Bone–marrow macrophages were stimulated towards M1 using LPS and IFNγ before treatment by PLP-liposomes. M1 and M2 markers were determined using RT-PCR.

Results

Microarray analysis of biopsies of inflamed synovium during antigen induced arthritis (AIA) showed an increased M1 signature characterized by upregulation of IL-1β, IL-6 and FcγRI starting from day 1 and lasting up until day 7 after arthritis induction. The M2 signature remained low throughout the 7 day course of arthritis. Treatment of AIA with intravenously delivered Lip-PLP strongly suppressed joint swelling and synovial infiltration whereas colloidal gold containing liposomes exclusively targeted the macrophages within the inflamed synovial intima layer. In vitro studies showed that Lip-PLP phagocytosed by M1 macrophages resulted in a suppression of the M1 phenotype and induction of M2 markers (IL-10, TGF-β, IL-1RII, CD163, CD206 and Ym1). In vivo, Lip-PLP treatment strongly suppressed M1 markers (TNF-α, IL-1β, IL-6, IL-12p40, iNOS, FcγRI, Ciita and CD86) after local M1 activation of lining macrophages with LPS and IFN-γ and during experimental AIA and immune complex arthritis (ICA). In contrast, M2 markers were not significantly upregulated in antigen-induced arthritis and down regulated in immune complex arthritis.

Conclusion

This study clearly shows that systemic treatment with PLP-liposomes selectively targets synovial lining macrophages and inhibits M1 activation. In contrast to in vitro findings, PLP-liposomes do not cause a shift of synovial lining macrophages towards M2.

Prospective study to assess fluid accumulation and tenosynovial changes in the aromatase inhibitor-induced musculoskeletal syndrome: 2-year follow-up data

BACKGROUND

Aromatase inhibitors (AIs) frequently lead to the AI-induced musculoskeletal syndrome (AIMSS). Looking into its pathophysiology, 6 months of AI therapy thickens the tendon sheath with intra-articular fluid (IAF) retention and loss of grip strength. We here report 24-month follow-up data.

PATIENTS AND METHODS

A prospective cohort study of 33 postmenopausal breast cancer patients received adjuvant endocrine therapy; 27 received an AI and 6 received tamoxifen. At baseline, 6 and 24 months patients had a rheumatologic examination, including a grip strength test, and magnetic resonance imaging of both hands and wrists. The primary end point was tenosynovial changes; secondary end points were changes in morning stiffness, grip strength and IAF.

RESULTS

Twenty-three AI and 5 tamoxifen patients completed all investigations. Between month 6 and 24, IAF further increased in AI users (P = 0.04) but not in tamoxifen users, and grip strength further decreased in both groups. The worsened tenosynovial changes were strongly correlated with a decrease in grip strength. At 24 months, morning stiffness continued to be present in over a third of AI users.

CONCLUSION

AIMSS represents a substantial problem in breast cancer patients. It is associated with tenosynovial changes, IAF retention, joint stiffness and loss of grip strength that do not improve with prolonged use.

Anti-epileptic drugs inhibit viability of synoviocytes in vitro

INTRODUCTION AND OBJECTIVE

The hyperplasia of synovial fibroblasts is considered to be essential for the evolution of joint destruction in rheumatoid arthritis (RA). Previously, we reported that anti-rheumatic drugs, both COX inhibitors and disease-modifying anti-rheumatic drugs inhibit proliferation of synoviocytes in vitro. The presented study investigates the effect of anti-epileptic drugs on the viability and proliferation of synovial fibroblasts in vitro.

METHODS

Experiments were conducted on human synoviocytes derived from an RA patient and rabbit synoviocytes cell line HIG-82. Cell proliferation and viability were assessed by means of BrdU assay and MTT assay, respectively. The IC50 value (the concentration of drug necessary to induce 50% inhibition) together with confidence limits was calculated.

RESULTS

Carbamazepine inhibited proliferation of human fibroblasts and viability of HIG-82 with IC 50 values of 86 µM and 82 µM, respectively. Diphenylhydantoin, valproate and phenobarbital inhibited viability of HIG-82 cells with the IC50 values of 110, 500 and 1031 µM, respectively.

CONCLUSION

Based on these findings, it can be suggested that anti-epileptic drugs may have a disease-modifying effect on rheumatoid synovial proliferation.

[Effects of qubi zhentong recipe on the expressions of IL-1beta, IL-8, and VEGF in the synovial of rats with collagen-inducing arthritis]

OBJECTIVE

To research the effects of Qubi Zhentong Recipe (QZR) on the expressions of interleukin-1beta (IL-1beta), interleukin-8 (IL-8), and vascular endothelial growth factor (VEGF) in the synovial of rats with collagen-inducing arthritis (CIA), and to discuss its mechanisms of action.

METHODS

Healthy male Wistar rats were recruited and randomly divided into the model group ( n = 50) and the normal control group (n = 10). Rats of the model group were injected with type II collagen of bovine (BC II) emulsion in the tail and nape to establish the CIA model. After successful modeling, 30 successfully modeled rats were selected and randomly divided into three groups, i.e., the model group (n = 10), the QZR group (n = 10), and the methotrexate (MTX) group (n = 10). Rats in the normal control group and the model group were administered with physiological saline by gastrogavage, while those in the QZR group were administered with QZR at 22.9 g/kg by gastrogavage. All medication was performed once daily. The rats in the MTX group were administered with MTX suspension at 0.78 mg/kg by gastrogavage, once per week. After 30-day treatment, the levels of IL-1beta, IL-8, and VEGF in the synovial were detected by immunohistochemical method. The arthritis index (AI) was scored before and after medication.

RESULTS

After treatment the AL score of the QZR group and the MTX group was obviously lower than that of the model group (P < 0.01). The AI score of the two drug groups were lower than that before treatment (P < 0.01). Compared with the normal control group, the expression levels of IL-1beta, IL-8, and VEGF obviously increased in the model group (P < 0.01). Compared with the model group, the expression levels of IL-1beta, IL-8, and VEGF were significantly lower in the two drug groups (P < 0.01). But there was no statistical difference between the QZR group and the MTX group (P > 0.05).

CONCLUSION

Decreasing the expression levels of IL-1beta, IL-8, and VEGF in the synovial of CIA rats may be one of the mechanisms for treating CIA by QZR.

[Recurrent intra-articular bleeding episodes in haemophiliacs. Treatment outcomes in the patients at the university hospital motol in 1985-2005]

PURPOSE OF THE STUDY

Chronic synovitis is a common finding in people with haemophilia. It regularly appears after recurrent episodes of intra-articular bleeding. The bleeding originates from the subsynovial venous plexus underlying the capsule where a lack of thromboplastic activity has been demonstrated. Therefore, the changed synovium appears to be a treatment target. There are several methods which can be used to remove the synovial layer from the joint. The aim of our study was to asses the efficacy of different treatment approaches used in a group of haemophiliacs between 1985 and 2005 in our hospital.

MATERIAL AND METHODS

A group of 30 patients with bleeding disorders was evaluated in the study. There were 29 men with haemophilia and one woman with von Wilebrandt factor deficiency. Their age ranged from 6 to 18 (median 13) years. They underwent a total of 68 interventions including surgical synovectomy (n=28), radionuclide synovectomy (n=33) and corticosteroid instillation (n=7). The necessity of a repeat intervention was used as a criterion of successful treatment.

RESULTS

In the group of surgical synovectomies, 22% of the patients required repeat operations, in the group of radiation synovectomy, this was 9% and, in the group treated with corticosteroids, this was 43%. The average hospitalisation time was 50 days for surgical procedures (19-133 days) and 7 days for radiation synovectomy procedures (4-13 days).

DISCUSSION

In 1994 Merchan presented seven excellent or good results in a group of 10 knees evaluated 1 year after treatment with methylprednisolone. Six years later he reported that "five years after completion of treatment, all results of the observed patients were poor". Generally, corticosteroids will reduce synovitis in the majority of patients but the effect is temporary. A complete remission is a very rare situation under corticosteroid treatment. The experience with surgical synovectomies is not recent and this method is described as carrying a high risk of complications and requiring a high amount of coagulating factor consumption. There are several recent reports on the application of Yttrium-90: in Madrid they evaluated treated joints (knees, ankles and elbows, n = 66) in 44 patients aged from 9 to 39 years. The results were good in less than half of the knees and ankles. The treatment of elbows was more successful. It was recommended to perform synoviorthesis at the early stages of synovitis. In Israel, they reported that a decrease in the number of bleeding episodes was achieved in 80% of 115 patients treated with Yttrium-90; in 15% of them, bleeding in the treated joints stopped completely. In Izmir, Yttrium was used in the treatment of knees, elbows, ankles and also shoulders in children and young adults (3-25 years). The method was found to be safe and effective. Brazilian authors have experience with the treatment of knees, ankles, elbows and shoulders too; they have concluded that this method represents an important resource for the treatment of chronic haemophilic synovitis and markedly reduces joint bleeding frequency and pain, irrespective of the radiographic stage and inhibitor status. While the European Association of Nuclear Medicine (EANM) recommend using 186Re-sulfide for treatment in medium-sized joints, Chinese authors have published a study comparing the effect of using three different doses of 186Re-sulfide in the treatment of chronic synovitis in knees. Their patients have received an amount of radionuclide according to the thickness of their synovial layer measured on MRI, with the result that 22 patients exhibited significant reduction in synovial thickness. A reduction in the number of bleeding episodes was reached in 71% of the patients within an 18-month period. No significant differences were found among the groups receiving different radioactivity doses. In Turkey, 35 elbows, 26 ankles and two shoulders in 49 patients aged between 3 and 30 years were treated with 186Re. The patients were followed up from 6 months to 3 years. At 6 months after the procedure, 81% of the elbows and 86% of the ankles with grade II synovitis were free from bleeding, as well as 53% and 44% of the elbows and ankles with grade III synovitis, respectively.

CONCLUSIONS

Radiation synovectomy appears to be the method of choice in the treatment of recurrent bleeding in the joint cavity in people with haemophilia. The efficacy of surgical synovectomy is lower in comparison with radiation synovectomy. Risks associated with surgery and anaesthesia, the need of hospitalisation and a prolonged period of rehabilitation are bothering. On the contrary, the application of corticosteroids cannot be recommended as a good method to treat recurrent haemarthroses.

Regulation of inflammatory responses in tumor necrosis factor-activated and rheumatoid arthritis synovial macrophages by JAK inhibitors

OBJECTIVE

JAK inhibitors have been developed as antiinflammatory and immunosuppressive agents and are currently undergoing testing in clinical trials. The JAK inhibitors CP-690,550 (tofacitinib) and INCB018424 (ruxolitinib) have demonstrated clinical efficacy in rheumatoid arthritis (RA). However, the mechanisms that mediate the beneficial actions of these compounds are not known. The purpose of this study was to examine the effects of both JAK inhibitors on inflammatory and tumor necrosis factor (TNF) responses in human macrophages.

METHODS

In vitro studies were performed using peripheral blood macrophages derived from healthy donors and treated with TNF and using synovial fluid macrophages derived from patients with RA. Levels of activated STAT proteins and other transcription factors were detected by Western blotting, and gene expression was measured by real-time polymerase chain reaction analysis. The in vivo effects of JAK inhibitors were evaluated in the K/BxN serum-transfer model of arthritis.

RESULTS

JAK inhibitors suppressed the activation and expression of STAT-1 and downstream inflammatory target genes in TNF-stimulated and RA synovial macrophages. In addition, JAK inhibitors decreased nuclear localization of NF-κB subunits in TNF-stimulated and RA synovial macrophages. CP-690,550 significantly decreased the expression of interleukin-6 in synovial macrophages. JAK inhibitors augmented nuclear levels of NF-ATc1 and cJun, followed by increased formation of osteoclast-like cells. CP-690,550 strongly suppressed K/BxN serum-transfer arthritis, which is dependent on macrophages, but not lymphocytes.

CONCLUSION

Our findings demonstrate that JAK inhibitors suppress macrophage activation and attenuate TNF responses and further suggest that suppression of cytokine/chemokine production and innate immunity contribute to the therapeutic efficacy of JAK inhibitors.

Hypoxia-induced endogenous prostaglandin E2 negatively regulates hypoxia-enhanced aberrant overgrowth of rheumatoid synovial tissue

OBJECTIVE

During isometric exercise, the synovial joint tissue is prone to hypoxia, which is further enhanced in the presence of synovial inflammation. Hypoxia is also known to induce inflammatory cascades, suggesting that periodic hypoxia perpetuates synovitis in rheumatoid arthritis. We previously established an ex vivo cellular model of rheumatoid arthritis using the synovial tissue-derived inflammatory cells, which reproduced aberrant synovial overgrowth and pannus-like tissue development in vitro. Using this model, we investigated the regulatory mechanism of synovial cells against hypoxia in rheumatoid arthritis.

METHODS

Inflammatory cells that infiltrated synovial tissue from patients with rheumatoid arthritis were collected without enzyme digestion, and designated as synovial tissue-derived inflammatory cells. Under normoxia or periodic hypoxia twice a week, their single-cell suspension was cultured in medium alone to observe an aberrant overgrowth of inflammatory tissue in vitro. Cytokines produced in the culture supernatants were measured by enzyme-linked immunosorbent assay kits.

RESULTS

Primary culture of the synovial tissue-derived inflammatory cells under periodic hypoxia resulted in the attenuation of the spontaneous growth of inflammatory tissue in vitro compared to the culture under normoxia. Endogenous prostaglandin E2 (PGE2) production was enhanced under periodic hypoxia. When endogenous PGE2 was blocked by indomethacin, the aberrant tissue overgrowth was more enhanced under hypoxia than normoxia. Indomethacin also enhanced the production of tumor necrosis factor-α (TNF-α), macrophage colony-stimulating factor (M-CSF), and matrix metalloproteinase-9 (MMP-9) under periodic hypoxia compared to normoxia. The EP4-specific antagonist reproduced the effect of indomethacin. Exogenous PGE1 and EP4-specific agonist effectively inhibited the aberrant overgrowth and the production of the inflammatory mediators under periodic hypoxia as well as normoxia.

CONCLUSIONS

The enhancing effect of periodic hypoxia on the aberrant overgrowth of rheumatoid synovial tissue was effectively down-regulated by the simultaneously induced endogenous PGE2.

[Effect of Bushen Qianggu decoction on the proliferation of synovial fibroblasts and expression of PCNA and Bcl-2]

OBJECTIVE

To observe the effects of Bushen Qianggu decoction proliferation and PCNA and Bcl-2 expression.

METHODS

Serum containing BQD was made and synovial fibroblasts were separated and cultured and passaged in vitro. Four groups were divided as 20% blank control group, serum containing 20% Tripterygium wilfordii multi-glycosides drug (TWMD), 20% of serum containing high and low of BQD, respectively. Serum containing drugs of different concentration were added into the synovial fibroblasts of the third generation, and then the synovial fibroblasts were cultured continued. The effects of different drugs on synovial fibroblasts and PCNA and Bcl-2 expression were observed.

RESULTS

Compared with the control serum, BQD-containing serum promoted the apoptosis of synovial fibroblasts (P < 0.000 1); especially, high dose could inhibit proliferation. The expression of PCNA and Bcl-2 was significantly lower in BQD-containing serum (P < 0.000 1 vs control group).

CONCLUSION

BQD can promote the apoptosis of synovial fibroblasts by improving of expression of PCNA and Bcl-2, which may be one of the mechanisms of BQD in preventing and treating osteoporosis of rheumatoid arthritis.

Active compound of Zingiber cassumunar Roxb. down-regulates the expression of genes involved in joint erosion in a human synovial fibroblast cell line

Rheumatoid arthritis (RA) is a chronic inflammatory disease of the synovium. It is involved in up-regulation of pro-inflammatory cytokines and matrix metalloproteinases (MMPs), resulting in joint inflammation and erosion. Zingiber cassumunar Roxb. has long been used to reduce joint pain and inflammation. This study aimed to investigate the inhibitory activities of an active compound of Z. cassumunar, (E)-4-(3',4'-dimethoxyphenyl)but-3-en-1-ol (compound D), against cytokine-induced up-regulation of catabolic genes involved in cartilage degradation in RA. Synovial fibroblast cell line, SW982, was cultured in media containing interleukin-1β (IL-1β), in the presence or absence of compound D at the concentration range of 1 to 100 µM. After 24 hours, the cells were analyzed for the expressions of MMPs, IL-1β and interleukin-1β-converting enzyme (ICE) by RT-PCR. MMPs activities in the culture media were analyzed by zymographic techniques. Dexamethasone was used as the positive control. It was found that compound D at the concentration of 10 - 100 µM significantly decreased the mRNA expressions of MMP-1, -2, -3, and -13 which was induced by IL-1β (P<0.05) concomitantly with a decrease in activities of these MMPs in the culture media. An increase in the mRNA expression of IL-1β and ICE was also suppressed by compound D. The results suggest that the potent activities of this compound may be involved in the reduction of IL-1β protein synthesis in both pro-form and active form which played an important role in up-regulation of MMPs. This study first revealed the chondroprotective activity of Z. cassumunar in the transcriptional level by suppressing cytokine-induced catabolic genes which caused cartilage erosion in RA.

[Effects of wenhua juanbi recipe on the gene expression profile of the synovium in collagen-induced arthritic rats]

OBJECTIVE

To study the effects of Wenhua Juanbi recipe (WJR) on the gene expression profile of the synovium in collagen-induced arthritis (CIA) rats, and to explore its mechanisms for treating CIA.

METHODS

The CIA model was induced by intradermal injection of bovine collagen type II emulsion from the tail of 40 healthy male Wistar rats. Selected 16 successfully modeled rats were randomly divided into the model group and the WJR-treated group, 8 in each group. WJR at the daily dose of 22.9 g/kg was given to rats in the WJR-treated group by gastrogavage, while normal saline was given to those in the model group. Both were performed once daily, for 30 successive days. By the end of medication, the total RNA was extracted from the synovium of rats in the two groups. The gene expression profile of each sample was analyzed using Illumina oligonucleotide microarray.

RESULTS

Compared with the model group, after the intervention of WJR, 222 differentially expressed genes were identified in CIA rats, including 76 genes up-regulated (such as RatNP-3b and so on) and 146 downregulated (such as Angptl 2, Muc1, bcl-2, and so on). The differential genes were mainly involved with apoptosis, angiopoietin, defensin gene, cytokine, signal transduction, oncogene, etc.

CONCLUSION

WJR played a role in treating CIA multi-target possibly through regulating and controlling multiple genes expressions. Wenhua Juanbi Recipe; collagen-induced arthritis; synovium; gene expression

IL-22 induced cell proliferation is regulated by PI3K/Akt/mTOR signaling cascade

OBJECTIVE

Interleukin 22 (IL-22), a relatively new cytokine has been found to induce significant proliferation of human keratinocytes and fibroblast like synoviocytes (FLS) and thus plays an important role in the pathogenesis of autoimmune diseases like psoriasis and rheumatoid arthritis (RA) which are characterized by hyperproliferation of keratinocytes and FLS respectively. PI3K/Akt/mTOR signaling cascade plays crucial role in cell growth and survival. Therefore our objective was to see the regulatory role of PI3K/Akt/mTOR signaling cascade in IL-22 induced proliferation of keratinocytes and FLS.

METHODS

Normal human epidermal keratinocytes (NHEK) and FLS were isolated from skin of healthy volunteer's undergone plastic surgery and synovial tissue of psoriatic arthritis (PsA) and RA patients respectively. IL-22 induced proliferation of NHEK and FLS was measured by MTT assay. Phosphorylation of Akt/mTOR was determined by western blot assay and further confirmed by real time polymerase chain reaction (RT-PCR).

RESULTS

We observed that IL-22 induced significant proliferation of NHEK and FLS which was effectively inhibited by dual kinase (PI3K/mTOR) inhibitor, NVP-BEZ235 and specific mTOR inhibitor, Rapamycin. In NHEK and FLS, IL-22 significantly induced phosphorylation of Akt and mTOR which was effectively blocked by Rapamycin and NVP-BEZ235. Further we did RT-PCR in NHEK and found that IL-22 significantly upregulated AKT1 and MTOR gene.

CONCLUSION

These results show that IL-22 induced proliferation of NHEK and FLS is dependent on PI3K/Akt/mTOR signaling pathway. This novel observation provides the scope to develop new therapeutics targeting PI3K/Akt/mTOR signaling pathway in autoimmune diseases like psoriasis and rheumatoid arthritis.

Future therapeutics for osteoarthritis

Osteoarthritis (OA) is a disease of the joints that affects several million individuals worldwide. This disease, which involves mainly the diarthrodial joints, is chronic and develops slowly over decades, making it very difficult to precisely identify the different etiological and risk factors that influence its onset. At present, most therapies for OA are symptomatic. This review will focus on new OA therapeutics in development that are directed toward pain relief as well as others with the potential to reduce or stop the progression of the disease (DMOADs). This article is part of a Special Issue entitled "Osteoarthritis".

[Effects of sinomenine and methotrexate on fibroblast-like synoviocytes in rheumatoid arthritis]

OBJECTIVE

To investigate the effects of sinomenine (SIN) and methotrexate (MTX) on the proliferation and apoptosis of in vitro cultured fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA) patients, as well as the expression of osteoclast differentiation factor in FLS.

METHODS

FLS were isolated from the synovium of RA patients and cultured in vitro. FLS were incubated with different concentrations of SIN and MTX respectively or combined: 0.001, 0.010, 0.100, 1.000 mg/mL SIN; 0.001, 0.010, 0.100, 1.000 mg/mL MTX; 0.001 mg/mL SIN + 0.001 mg/mL MTX, 0.010 mg/mL SIN + 0.010 mg/mL MTX, 0.100 mg/mL SIN + 0.100 mg/mL MTX, 1.000 mg/mL SIN + 1.000 mg/mL MTX, namely SIN1, 2, 3, 4 groups; MTX1, 2, 3, 4 groups and the combination 1, 2, 3, 4 groups. The medium without drugs was used as a control group. There was a total of 13 groups, each group with 3 complex holes. MTT was applied to detect the growth of FLS. The flow cytometry was applied to detect the apoptosis of FLS. The expressions of FLS receptor activator of nuclear factor kappa B ligand (RANKL) mRNA and osteoprotegerin (OPG) mRNA were observed by semi-quantitative RT-PCR.

RESULTS

Compared with the control group, RA FLS proliferation OD values of all the drug groups were lower (P < 0.05). The RA FLS apoptosis OD value of the combination 3 group increased, the OPG mRNA expression increased, the expression of RANKL mRNA decreased with statistical difference (P < 0.05). The RA proliferation OD values of the SIN3 group and the MTX3 group increased when compared with the combination 3 group (P < 0.05).

CONCLUSIONS

SIN and MTX had synergistic effects in inhibiting FLS. This might be one of the mechanisms for inhibiting RA bone damage.

Aciculatin inhibits granulocyte colony-stimulating factor production by human interleukin 1β-stimulated fibroblast-like synoviocytes

The expression of granulocyte colony-stimulating factor (G-CSF), the major regulator of neutrophil maturation, by human fibroblast-like synoviocytes (FLS) can be stimulated by the inflammatory cytokine interleukin-1β (IL-1β). G-CSF is known to contribute to the pathologic processes of destructive arthritis, but the induction mechanism remains unknown. The aims of this study were to identify the signaling pathways involved in IL-1β-stimulated G-CSF production and to determine whether this process was inhibited by aciculatin (8-((2R,4S,5S,6R)-tetrahydro-4,5-dihydroxy-6-methyl-2H-pyran-2-yl)-5-hydroxy-2-(4-hydroxyphenyl)-7-methoxy-4H-chromen-4-one), the major bioactive component of Chrysopogon aciculatus. IL-1β-induced cytokine expression was evaluated by measuring mRNA and protein levels by RT-PCR, ELISA, and Milliplex® assay. Whether aciculatin inhibited IL-1β-stimulated G-CSF expression, and if so, how, were evaluated using western blot assay, an electrophoretic mobility shift assay, and a reporter gene assay. Neutrophil differentiation was determined by Wright-Giemsa staining and flow cytometry. Aciculatin markedly inhibited G-CSF expression induced by IL-1β (10 ng/mL) in a concentration-dependent manner (1-10 µM). In clarifying the mechanisms involved, aciculatin was found to inhibit the IL-1β-induced activation of the IκB kinase (IKK)/IκB/nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways by suppressing the DNA binding activity of the transcription factors NF-κB and activator protein (AP)-1. Furthermore, aciculatin significantly inhibited the G-CSF-mediated phosphorylation of Janus kinase-signal transducer and activator of transcription (JAK-STAT) and Akt and neutrophil differentiation from precursor cells. Our results show that aciculatin inhibits IL-1β-stimulated G-CSF expression and the subsequent neutrophil differentiation, suggesting that it might have therapeutic potential for inflammatory arthritis.