NF-kappa B in rheumatoid arthritis: a pivotal regulator of inflammation, hyperplasia, and tissue destruction

Anti-angiogenic effect of total saponins of Rhizoma Dioscorea nipponica on collagen induced-arthritis in rats

Rheumatoid arthritis (RA) is a common chronic autoimmune and incurable disease. The aim of the present study was to investigate the therapeutic effect and mechanism of the total saponins of Rhizoma Dioscorea nipponica (TSRDN) in RA. A collagen induced-arthritis (CIA) rat model was established. CIA rats were randomly divided into three groups and lavaged with an equal volume of solvent (CIA group), TSRDN (25 mg/kg/day, RDN group) and tripterygium (TP; 12 mg/kg/day, TP group) for 21 days, respectively. Normal rats served as a control group. Hematoxylin-eosin (HE) staining was used to observe the histopathological injury of synovial tissues. The level of CD31, which used for marking and counting, micro vessel density (MVD) and the expression levels of vascular endothelial growth factor (VEGF) and signal transducer and activator of transcription 3 (STAT3) were detected by immunohistochemical analysis. Additionally, the DNA-binding activity of nuclear factor-κB (NF-κB) was determined using an ELISA kit. HE staining showed obvious synovial hyperplasia, inflammatory cell infiltration, pannus formation, cartilage and bone erosion in the CIA group rats. In addition, compared with control group, the level of MVD, the expression of VEGF and STAT3, and the DNA-binding activity of NF-κB were all increased in CIA group rat synovial tissue (all P<0.01); however, TSRDN or tripterygium were able to inhibit these changes (all P<0.01). It was speculated that TSRDN may prevent angiogenesis by inhibiting the expression of STAT3 and the DNA-binding activity of NF-κB p65, thereby potentially improving CIA.

Effect of N-Feruloylserotonin and Methotrexate on Severity of Experimental Arthritis and on Messenger RNA Expression of Key Proinflammatory Markers in Liver

Rheumatoid arthritis (RA) is a chronic inflammatory disease, leading to progressive destruction of joints and extra-articular tissues, including organs such as liver and spleen. The purpose of this study was to compare the effects of a potential immunomodulator, natural polyphenol N-feruloylserotonin (N-f-5HT), with methotrexate (MTX), the standard in RA therapy, in the chronic phase of adjuvant-induced arthritis (AA) in male Lewis rats. The experiment included healthy controls (CO), arthritic animals (AA), AA given N-f-5HT (AA-N-f-5HT), and AA given MTX (AA-MTX). N-f-5HT did not affect the body weight change and clinical parameters until the 14th experimental day. Its positive effect was rising during the 28-day experiment, indicating a delayed onset of N-f-5HT action. Administration of either N-f-5HT or MTX caused reduction of inflammation measured as the level of CRP in plasma and the activity of LOX in the liver. mRNA transcription of TNF-α and iNOS in the liver was significantly attenuated in both MTX and N-f-5HT treated groups of arthritic rats. Interestingly, in contrast to MTX, N-f-5HT significantly lowered the level of IL-1β in plasma and IL-1β mRNA expression in the liver and spleen of arthritic rats. This speaks for future investigations of N-f-5HT as an agent in the treatment of RA in combination therapy with MTX.

Cell-penetrating peptides: Possible transduction mechanisms and therapeutic applications

Cell-penetrating peptides (CPPs), also known as protein transduction domains, are a class of diverse peptides with 5-30 amino acids. CPPs are divided into cationic, amphipathic and hydrophobic CPPs. They are able to carry small molecules, plasmid DNA, small interfering RNA, proteins, viruses, imaging agents and other various nanoparticles across the cellular membrane, resulting in internalization of the intact cargos. However, the mechanisms of CPP internalization remain to be elucidated. Recently, CPPs have received considerable attention due to their high transduction efficiency and low cytotoxicity. These peptides have a significant potential for diagnostic and therapeutic applications, such as delivery of fluorescent or radioactive compounds for imaging, delivery of peptides and proteins for therapeutic application, and delivery of molecules into induced pluripotent stem cells for directing differentiation. The present study reviews the classifications and transduction mechanisms of CPPs, as well as their potential applications.

TLR4 Signaling in MPP⁺-Induced Activation of BV-2 Cells

Aims. This work was conducted to establish an in vitro Parkinson's disease (PD) model by exposing BV-2 cells to 1-methyl-4-phenylpyridinium (MPP⁺) and exploring the roles of TLR2/TLR4/TLR9 in inflammatory responses to MPP⁺. Methods/Results. MTT assay showed that cell viability of BV-2 cells was 84.78 ± 0.86% and 81.18 ± 0.99% of the control after incubation with 0.1 mM MPP⁺ for 12 hours and 24 hours, respectively. Viability was not significantly different from the control group. With immunofluorescence technique, we found that MPP⁺ incubation at 0.1 mM for 12 hours was the best condition to activate BV-2 cells. In this condition, the levels of TNF-α, IL-1β, and iNOS protein were statistically increased compared to the control according to ELISA tests. Real time RT-PCR and western blot measurements showed that TLR4 was statistically increased after 0.1 mM MPP⁺ incubation for 12 hours. Furthermore, after siRNA interference of TLR4 mRNA, NF-κB activation and the levels of TNF-α, IL-1β, and iNOS were all statistically decreased in this cell model. Conclusion. MPP⁺ incubation at the concentration of 0.1 mM for 12 hours is the best condition to activate BV-2 cells for mimicking PD inflammation in BV-2 cells. TLR4 signalling plays a critical role in the activation of BV-2 cells and the induction of inflammation in this cell model.

The Anti-inflammatory Effect of GV1001 Mediated by the Downregulation of ENO1-induced Pro-inflammatory Cytokine Production

GV1001 is a peptide derived from the human telomerase reverse transcriptase (hTERT) sequence that is reported to have anti-cancer and anti-inflammatory effects. Enolase1 (ENO1) is a glycolytic enzyme, and stimulation of this enzyme induces high levels of pro-inflammatory cytokines from concanavalin A (Con A)-activated peripheral blood mononuclear cells (PBMCs) and ENO1-expressing monocytes in healthy subjects, as well as from macrophages in rheumatoid arthritis (RA) patients. Therefore, this study investigated whether GV1001 downregulates ENO1-induced pro-inflammatory cytokines as an anti-inflammatory peptide. The results showed that GV1001 does not affect the expression of ENO1 in either Con A-activated PBMCs or RA PBMCs. However, ENO1 stimulation increased the production of pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6, and these cytokines were downregulated by pretreatment with GV1001. Moreover, p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB were activated when ENO1, on the surface of Con A-activated PBMCs and RA PBMCs, was stimulated, and they were successfully suppressed by pre-treatment with GV1001. These results suggest that GV1001 may be an effective anti-inflammatory peptide that downregulates the production of pro-inflammatory cytokines through the suppression of p38 MAPK and NF-κB activation following ENO1 stimulation.

Ginsenoside metabolite compound K exerts joint-protective effect by interfering with synoviocyte function mediated by TNF-α and Tumor necrosis factor receptor type 2

Ginsenoside metabolite compound K (CK), metabolite of the ginsenoside, is considered to exert numerous pharmacological efficacies of ginsenoside, including anti-inflammation and immunoregulatory effects. Rheumatoid arthritis (RA) is a multi-systemic autoimmune disease characterized by hyperplastic synovial membrane and systemic inflammation, which ultimately lead to progressive destructive inflammatory arthropathy. To evaluate the potential joint-protective effects of CK and the underlying mechanism, adjuvant arthritis (AA) was induced by complete Freund's adjuvant in rats. After the onset of arthritis, The effect of CK on AA rats was evaluated by histopathology of the joint. The proliferation of fibroblast-like synoviocyte(FLS) was assayed by the Cell Counting Kit-8.The migration of FLS was assayed by transwell migration assay. Cytokines in the supernatant from FLS were measured by ELISA kit. Expression of Tumor Necrosis Factor Receptor Type 1(TNFR1) and Tumor Necrosis Factor Receptor Type 2(TNFR2) were detected by immunostaining analysis and western blot analysis. CK (80mg/kg) significantly ameliorated the histopathological change of joint in AA rats, balanced the RANKL/OPG ratio and attenuated the proliferation and migration of AA-FLS. CK suppressed the secretion of proinflammatory cytokines TNF-α and downregulated the expression of TNFR2 on AA-FLS. In vitro CK also significantly suppressed proliferation, migration and secretion of AA-FLS mediated by TNF-α. Further studies showed that the effects of CK on AA-FLS were reversed by using glucocorticoid receptor (GR) antagonist (mifepristone). Our data suggest that CK exerts joint-protective effect by interfering with synoviocyte function mediated by TNF-α and TNFR2, and this effect may be mediated by GR.

Sneaking-ligand fusion proteins attenuate serum transfer arthritis by endothelium-targeted NF-κB inhibition

The nuclear transcription factor κB (NF-κB) is a crucial mediator of the inflammatory and immune response. The contribution of dysregulated NF-κB is established in the pathogenesis of arthritis. Accordingly, NF-κB represents an attractive molecular target for the development of therapeutic interventions in inflammatory diseases. However, ubiquitous pharmacologic suppression of NF-κB activity is limited by the hazards of toxic side effects and profound immunosuppression. Cell type-specific NF-κB inhibition with the "sneaking-ligand" approach could identify disease-relevant cell types and improve risk-benefit ratios of therapeutic interventions. Vascular endothelial cells act as a gatekeeper and are crucial for leukocyte recruitment into sites of inflammation. The endothelium-specific NF-κB inhibitor SLC1 ameliorates serum transfer arthritis in mice and protects against inflammation and cartilage destruction. In this chapter, we describe the SLC1 treatment schedule in the K/BxN serum transfer arthritis and present the evaluation system to analyze arthritis severity and histopathological alterations.

Investigation of the cytokine response to NF-κB decoy oligonucleotide coated polysaccharide based nanoparticles in rheumatoid arthritis in vitro models

Introduction

The transcription factor nuclear factor-kappa B (NF-κB) is highly involved in regulation of a number of cellular processes, including production of inflammatory mediators. Thus, this transcription factor plays a role in pathology of many diseases, including rheumatoid arthritis, an autoimmune disease hallmarked by an imbalance of pro and anti-inflammatory cytokines. Small nucleic acids with sequences that mimic the native binding site of NF-κB have been proposed as treatment options for RA; however due to low cellular penetration and a high degree of instability, clinical applications of these therapeutics have been limited.

Methods

Here, we describe the use of N-trimethyl chitosan-polysialic acid (PSA-TMC) nanoparticles coated with decoy oligodeoxynucleotides (ODNs) specific to transcription factor NF-κB (PSA-TMC-ODN) as a method to enhance the stability of the nucleic acids and facilitate increased cellular penetration. In addition to decoy ODN, PSA-TMC nanoparticles were loaded with RA therapeutic methotrexate (MTX), to assess the anti-inflammatory efficacy of a combination therapy approach. Two different in vitro models, a cell line based model as well as a primary RA cell model were used to investigate anti-inflammatory activity. One way ANOVA followed by Holm-Sidak stepdown comparisons was used to determine statistical significance.

Results

In general, free ODN did not significantly affect secretion of pro-inflammatory cytokines interleukin-6 (IL-6) and interleukin-8, (IL-8) while free MTX had variable efficacy. However, PSA-TMC-ODN and PSA-TMC-ODN-MTX resulted in significant decreases in the inflammatory mediators IL-6 and IL-8 in both cell models. In addition, PSA-TMC exhibited sufficient cellular uptake, as observed through fluorescence microscopy.

Conclusions

These results support our previous findings that PSA-TMC nanoparticles are an effective delivery vehicle for small nucleic acids, and effectively alter the pro-inflammatory state characteristic of RA.

Dietary extra virgin olive oil attenuates kidney injury in pristane-induced SLE model via activation of HO-1/Nrf-2 antioxidant pathway and suppression of JAK/STAT, NF-κB and MAPK activation

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by a widespread organ involvement. Recent studies have suggested that extra virgin olive oil (EVOO) might possess preventive effects on this immunoinflammation-related disease. However, its role in SLE remained unknown. In this work, we evaluated the effects of EVOO diet in a pristane-induced SLE model in mice. Three-month-old mice received an injection of pristane or saline solution and were fed with different experimental diets: sunflower oil diet or EVOO diet. After 24weeks, mice were sacrificed, spleens were collected and kidneys were removed for immunoinflammatory detections. The kidney expression of microsomal prostaglandin E synthase 1, heme oxygenase 1 (HO-1), nuclear factor E2-related factor 2 (Nrf-2), mitogen-activated protein kinases (MAPKs), Janus kinase/signal transducer and activator of transcription (JAK/STAT) and nuclear transcription factor-kappa B (NF-κB) pathways were studied by western blotting. In addition to macroscopic and histological analyses, serum matrix metalloproteinase 3 (MMP-3) levels and proinflammatory cytokines production in splenocytes were evaluated by enzyme-linked immunoassay. We have demonstrated that EVOO diet significantly reduced renal damage and decreased MMP-3 serum and PGE2 kidney levels as well as the proinflammatory cytokines production in splenocytes. Our data indicate that Nrf-2 and HO-1 protein expressions were up-regulated in those mice fed with EVOO and the activation of JAK/STAT, MAPK and NF-κB pathways were drastically ameliorated. These results support the interest of EVOO as a beneficial functional food exerting a preventive/palliative role in the management of SLE.

Collagen Induced Arthritis in DBA/1J Mice Associates with Oxylipin Changes in Plasma

Oxylipins play important roles in various biological processes and are considered as mediators of inflammation for a wide range of diseases such as rheumatoid arthritis (RA). The purpose of this research was to study differences in oxylipin levels between a widely used collagen induced arthritis (CIA) mice model and healthy control (Ctrl) mice. DBA/1J male mice (age: 6-7 weeks) were selected and randomly divided into two groups, namely, a CIA and a Ctrl group. The CIA mice were injected intraperitoneally (i.p.) with the joint cartilage component collagen type II (CII) and an adjuvant injection of lipopolysaccharide (LPS). Oxylipin metabolites were extracted from plasma for each individual sample using solid phase extraction (SPE) and were detected with high performance liquid chromatography/tandem mass spectrometry (HPLC-ESI-MS/MS), using dynamic multiple reaction monitoring (dMRM). Both univariate and multivariate statistical analyses were applied. The results in univariate Student's t-test revealed 10 significantly up- or downregulated oxylipins in CIA mice, which were supplemented by another 6 additional oxylipins, contributing to group clustering upon multivariate analysis. The dysregulation of these oxylipins revealed the presence of ROS-generated oxylipins and an increase of inflammation in CIA mice. The results also suggested that the collagen induced arthritis might associate with dysregulation of apoptosis, possibly inhibited by activated NF-κB because of insufficient PPAR-γ ligands.

The Role of the Transcriptional Regulation of Stromal Cells in Chronic Inflammation

Chronic inflammation is a common process connecting pathologies that vary in their etiology and pathogenesis such as cancer, autoimmune diseases, and infections. The response of the immune system to tissue damage involves a carefully choreographed series of cellular interactions between immune and non-immune cells. In recent years, it has become clear that stromal resident cells have an essential role perpetuating the inflammatory environment and dictating in many cases the outcome of inflammatory based pathologies. Signal transduction pathways remain the main focus of study to understand how stimuli contribute to perpetuating the inflammatory response, mainly due to their potential role as therapeutic targets. However, molecular events orchestrated in the nucleus by transcription factors add additional levels of complexity and may be equally important for understanding the phenotypic differences of activated stromal components during the chronic inflammatory process. In this review, we focus on the contribution of transcription factors to the selective regulation of inducible proinflammatory genes, with special attention given to the regulation of the stromal fibroblastic cell function and response.

O-linked N-acetylglucosamine glycosylation of p65 aggravated the inflammation in both fibroblast-like synoviocytes stimulated by tumor necrosis factor-α and mice with collagen induced arthritis

Introduction

We investigated the inflammatory potential of O-linked N-acetylglucosamine glycosylation (O-GlcNAcylation) of p65 in rheumatoid arthritis (RA).

Methods

Fibroblast-like synoviocytes (FLS) and MH7A cells were treated with synthetic ThiaMet-G (200 μM), an O-GlcNAcase (OGA) inhibitor, followed by tumor necrosis factor (TNF)-α (10 μg/mL). Proliferation of synovial cells was measured by MTT assay, and the levels of mRNAs encoding pro-inflammatory molecules were quantitated by RT-PCR. The nuclear localization of O-GlcNAcylated of p65 and its DNA binding affinity and transcriptional activity were assessed. The severity assessment of arthritis and a histopathological examination were done in mice with collagen induced arthritis (CIA). ThiaMet-G (20 mg/kg) intraperitoneal injection was done every other day for 26 days. Fluorescence-activated cell sorting (FACS) analysis of T cells was performed.

Results

Hyper-O-GlcNAcylation increased the proliferation and mRNA expression of pro-inflammatory genes in synoviocytes stimulated by TNF-α. Moreover, O-GlcNAcylation of p65 enhanced its proportion of nuclear localization, DNA binding affinity and transcriptional activity. In CIA mice, ThiaMet-G significantly aggravated the severity of arthritis clinically and histologically, and it also increased CD4 + IFN-γ + T cells and CD4 + IL-17+ T cells.

Conclusions

O-GlcNAcylation of p65 increased the effects of TNF-α-mediated inflammation both in vitro (in synovial cells) and in vivo (in mice with CIA).

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0762-7) contains supplementary material, which is available to authorized users.

The effects of arctigenin on human rheumatoid arthritis fibroblast-like synoviocytes

CONTEXT

Rheumatoid arthritis fibroblast-like synoviocytes (RAFLSs) play an important role in the initiation and progression of RA, which are resistant to apoptosis and proliferate in an anchorage-independent manner.

OBJECTIVE

The effects of arctigenin on the proliferation and apoptosis of RAFLSs were explored.

MATERIALS AND METHODS

Arctigenin (0-160 µM) was used to treat RAFLSs for 48 h. Cell viability and apoptosis were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay and annexin V/propidium iodide staining. Western blot analysis was performed to detect the changes in apoptosis-related genes.

RESULTS AND DISCUSSION

Arctigenin decreased cell viability by 23, 30, and 38% at the dose of 10, 20, and 30 µM, respectively. The half maximal inhibitory concentration (IC50) of arctignein on RAFLSs was about 38 µM. Moreover, 9, 15, and 21% of RAFLSs are induced apoptosis by 10, 20, and 30 µM of arctigenin. The apoptotic response was due to the loss of mitochondrial membrane potential, coupled with the release of cytochrome C into cytoplasm, the up-regulation of pro-apoptotic protein, Bax, and down-regulation of antiapoptotic protein, B cell lymphoma 2 (Bcl-2). The activation of mitochondrial pathway in arctigenin-treated RAFLSs induced the cleavage of caspase-9, caspase-3, and poly (ADP-ribose) polymerase (PARP). Additionally, arctigenin inhibited the nuclear translocation of p65, decreased the degradation of inhibitor of kappa B alpha (IκBα), and attenuated the phosphorylation of Akt.

CONCLUSION

Our results reveal that arctigenin inhibits cell proliferation and induces mitochondrial apoptosis of RAFLSs, which is associated with the modulation of NF-κB and Akt signaling pathways.

Cell-type specific penetrating peptides: therapeutic promises and challenges

Cell penetrating peptides (CPP), also known as protein transduction domains (PTD), are small peptides able to carry peptides, proteins, nucleic acid, and nanoparticles, including viral particles, across the cellular membranes into cells, resulting in internalization of the intact cargo. In general, CPPs can be broadly classified into tissue-specific and non-tissue specific peptides, with the latter further sub-divided into three types: (1) cationic peptides of 6-12 amino acids in length comprised predominantly of arginine, lysine and/or ornithine residues; (2) hydrophobic peptides such as leader sequences of secreted growth factors or cytokines; and (3) amphipathic peptides obtained by linking hydrophobic peptides to nuclear localizing signals. Tissue-specific peptides are usually identified by screening of large peptide phage display libraries. These transduction peptides have the potential for a myriad of diagnostic as well as therapeutic applications, ranging from delivery of fluorescent or radioactive compounds for imaging, to delivery of peptides and proteins of therapeutic potential, and improving uptake of DNA, RNA, siRNA and even viral particles. Here we review the potential applications as well as hurdles to the tremendous potential of these CPPs, in particular the cell-type specific peptides.

The Modified JiuWei QiangHuo Decoction Alleviated Severe Lung Injury Induced by H1N1 Influenza Virus by Regulating the NF- κ B Pathway in Mice

A new approach to treat infections of highly pathogenic influenza virus is to inhibit excessive innate immune response. JiuWei QiangHuo decoction has been used for centuries for the treatment of pulmonary disorders in China. In this study, we evaluated the anti-inflammatory activities of the modified JiuWei QiangHuo (MJWQH) decoction in the treatment of influenza A (H1N1) virus-induced severe pneumonia in mice. The results showed that MJWQH significantly increased the survival rate of H1N1-infected mice and suppressed the production of TNF-α, IL-1, IL-6, MCP-1, RANTES, and IFN-α on day 4 after infection. Moreover, oral administration of MJWQH efficiently inhibited virus replication and alleviated the severity of lung injuries. The results also showed that MJWQH may have potential therapeutic effect on severe lung injury induced by H1N1 virus by regulating the NF-κB pathway. Our study suggested that MJWQH might be an alternative therapy for the treatment of viral pneumonia.

Herb Network Analysis for a Famous TCM Doctor's Prescriptions on Treatment of Rheumatoid Arthritis

Traditional Chinese Medicine (TCM) doctors always prescribe various herbal formulae tailored to individual patients. However, there is still a lack of appropriate methods to study the rule and potential biological basis underlying the numerous prescriptions. Here we developed an Herb-Compound-Target-Disease coherent network approach to analyze 871 herbal prescriptions from a TCM master, Mr. Ji-Ren Li, in his clinical practice on treatment of rheumatoid arthritis (RA). The core herb networks were extracted from Mr. Li's prescriptions. Then, we predicted target profiles of compounds in core herb networks and calculated potential synergistic activities among them. We further found that the target sets of core herbs overlapped significantly with the RA related biological processes and pathways. Moreover, we detected a possible connection between the prescribed herbs with different properties such as Cold and Hot and the Western drugs with different actions such as immunomodulatory and hormone regulation on treatment of RA. In summary, we explored a new application of TCM network pharmacology on the analysis of TCM prescriptions and detected the networked core herbs, their potential synergistic and biological activities, and possible connections with drugs. This work offers a novel way to understand TCM prescriptions in clinical practice.

Bufalin, a bioactive component of the Chinese medicine chansu, inhibits inflammation and invasion of human rheumatoid arthritis fibroblast-like synoviocytes

Rheumatoid arthritis fibroblast-like synoviocytes (RAFLSs) contribute to the destruction of cartilage and bone by production of metalloproteinases (MMPs) into the synovial fluid and by direct invasion into extracellular matrix (ECM). Bufalin, a major component of Venenum Bufonis, can attenuate the invasion of various cancer cells. Here, we investigated the effects of bufalin on tumor necrosis factor-alpha (TNF-α)-induced invasion of RAFLSs. Western blot analysis and electrophoretic mobility shift assay were conducted to analyze the nuclear translocation of p65/nuclear factor-kappa B (NF-κB) and NF-κB DNA-binding activity. Semiquantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay were performed to assess the expression of cytokines. Our results revealed that TNF-α significantly increased p65 translocation into nucleus (P < 0.01) and enhanced NF-κB DNA-binding activity, which were dose-dependently inhibited by bufalin. Furthermore, bufalin attenuated the TNF-α-induced interleukin-1beta (IL-1β), IL-6, and IL-8 production in RAFLSs in a concentration-dependent manner. Interestingly, TNF-α-induced invasion of RAFLSs was dampened by the pretreatment of bufalin. Additionally, bufalin decreased the mRNA abundance and secretion of MMP-9 in TNF-α-treated RAFLSs. Our results reveal that bufalin can inhibit TNF-α-induced NF-κB activation, cytokine production, invasion, and MMP-9 expression in RAFLSs, indicating a therapeutic potential of bufalin on RA.

A novel therapeutic approach targeting rheumatoid arthritis by combined administration of morin, a dietary flavanol and non-steroidal anti-inflammatory drug indomethacin with reference to pro-inflammatory cytokines, inflammatory enzymes, RANKL and transcription factors

The present study was designed to assess the combined efficacy of morin, a dietary flavanol and non-steroidal anti-inflammatory drug indomethacin against adjuvant-induced arthritis in rats, an experimental model for rheumatoid arthritis. Arthritis was induced by intradermal injection of complete freund's adjuvant (0.1 ml) into the right hind paw of the Wistar albino rats. Morin (30 mg/kg b.wt), indomethacin (3 mg/kg b.wt) and combination of morin and indomethacin were administered intraperitoneally (from 11th to 20th day) after adjuvant injection. We have found that the activities/levels of lysosomal acid hydrolases (acid phosphatase, β-galactosidase, N-acetyl glucosaminidase and cathepsin-D), glycoproteins (hexose and hexosamine), urinary constituents (hydroxyproline and glycosaminoglycans), reactive oxygen species (LPO and NO), elastase, inflammatory mediators (TNF-α, IL-1β, MCP-1, VEGF and PGE2) and paw edema were significantly increased in arthritic rats compared to controls. Whereas, the anti-oxidant status (SOD, CAT, GPx, glutathione, and ceruloplasmin), body weight and bone collagen was found to be decreased. The mRNA expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-17, IL-6 and MCP-1), inflammatory enzymes (iNOS and COX-2), RANKL, and transcription factors (NF-kB p65 and AP-1) was found upregulated in the ankle joints of arthritic rats in qRT-PCR analysis. In addition, the increased protein expression of NF-kB p65 and COX-2 was also detected by immunohistochemical analysis. On the other hand, the above said imbalances were regulated back effectively to near normal as evidenced by the histopathological and radiological analysis on combined treatment with morin and indomethacin. Our study indicates that the combination therapy was more effective than either single drug alone in suppressing the pathogenesis of RA.

Lipid peroxidation-mediated inflammation promotes cell apoptosis through activation of NF-κB pathway in rheumatoid arthritis synovial cells

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic inflammation of multiple joints. The central pathogenesis of RA is the proliferation of synovial fibroblasts in response to inflammatory cytokines. However, some of the targeted therapies for inflammation reactions do not display significant clinical improvement after initiation of therapy. Thus, the relationship between inflammatory responses and RA therapy is still incompletely understood. In the present study, we proposed to determine whether enhanced inflammations may lead to cell apoptosis in rheumatoid arthritis synoviocytes. Our results indicated that products of lipid peroxidations, 4-HNE, may induce synovial intrinsic inflammations by activating NF-κB pathways and it may lead to cell apoptosis. Pharmacological inhibition of NF-κB activation may reduce the 4-HNE mediated inflammation responses and subsequent cell apoptosis. Our results may help to clarify the role of inflammations on RA development and imply that blocking NF-κB activation may be partly beneficial for human RA therapy. These findings might provide a mechanism-based rationale for developing new strategy to RA clinical therapy.

The effect of 4α,5α-epoxy-10α,14-dihydro-inuviscolide, a novel immunosuppressant isolated from Carpesium abrotanoides, on the cytokine profile in vitro and in vivo

The plant Carpesium abrotanoides (CA) is used in Asian herbal medicines as an insecticide and to treat bruises. However, the effect of single compounds from CA blooms and the mechanism of its immunosuppressive effect remain poorly understood. The aim of this study was to investigate the mechanism of the immunosuppressive effect in the three kinds of immune cells, and the immunosuppressive effect of CA bloom extract (CAE) in acute inflammation models (LPS and ConA-induced inflammation). Interleukin-6, IL-4, IL-13, IFNγ, and IL-10-but not TNFα-were significantly reduced in a dose-dependent manner by 4α,5α-epoxy-10α,14-dihydro-inuviscolide (INV). Furthermore, INV inhibited NF-κB transcriptional activation and IL-10 promoter activity in the same manner as for Bay11. Meanwhile, treatment with dexamethasone reduced the levels of IFNγ, but not IL-10, and resulted in no change in NF-κB transcriptional activation or the IL-10 promoter. INV did not affect PMA-induced IκB kinase complex phosphorylation, IκB degradation, or MAPK and the nuclear translocation of p65, as with DEX. The in vivo, CAE has an immunosuppressive effect on the LPS-induced inflammation response model by inhibiting the plasma level of IFNγ and IL-6 levels. CAE treatment also tends to attenuate the plasma level of IFNγ, IL-4, and IL-6 in ConA-induced inflammation. These findings indicate that INV causes the reduction of the cytokine profile by blocking the NF-κB transcription factor activation and the molecular mechanism by which INV operates could provide new insights into the unique mechanisms responsible for NF-κB inhibition, in contrast to established immunosuppressants, as a therapeutic agent for immunopathological treatment.

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.

Anti-neuroinflammatory effects of DPTP, a novel synthetic clovamide derivative in in vitro and in vivo model of neuroinflammation

Neuroinflammation is one of the critical pathological mechanisms influencing various neurodegenerative disorders. Most of the neurodegenerative diseases involve over-activation of microglial cells contributing to the demise of neurons. The objective of the current study is to evaluate the anti-inflammatory effect of novel synthetic clovamide derivative on the suppression of microglial activation in an in vitro and in vivo model of neuroinflammation. We have used lipopolysaccharide (LPS) to induce an inflammatory response in murine BV-2 microglial cells. Molecular tools like immunocytochemistry and immunoblotting were used to study the activity of novel synthetic clovamide derivative to inhibit inflammation induced by LPS in microglial cells. In in vivo experiments, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxicated mouse model of neuroinflammation was developed to investigate the anti-neuroinflammatory effects of DPTP [3-(3,4-Dihydroxy-phenyl)-2-[4-(3-trifluoromethylphenyl)-but-2-enoylamino]-propionic acid methyl ester]. DPTP was observed to reduce the proinflammatory response in BV-2 cells induced by LPS. Further investigation revealed that DPTP attenuated phosphorylation of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK), which was accompanied by a decrease in nuclear translocation of nuclear factor-κB (NF-κB) in LPS-treated BV2 microglia. Moreover, prophylactic treatment with DPTP (20mg/kg) for 7 days suppressed MPTP induced glial activation and behavioral impairment. Overall, our findings suggested that, DPTP exerts anti-neuroinflammatory effects against activated microglia in an in vitro and in vivo model and hence might be a promising therapeutic agent for alleviating the evolvement of neurodegenerative diseases associated with microglial activation.

Quantitative proteomic analysis of synovial tissue from rats with collagen-induced arthritis

The pathway networks involved in RA pathological process were analyzed by Ingenuity pathway analysis (IPA).

Multi-omic landscape of rheumatoid arthritis: re-evaluation of drug adverse effects

Objective: To provide a frame to estimate the systemic impact (side/adverse events) of (novel) therapeutic targets by taking into consideration drugs potential on the numerous districts involved in rheumatoid arthritis (RA) from the inflammatory and immune response to the gut-intestinal (GI) microbiome.

Methods: We curated the collection of molecules from high-throughput screens of diverse (multi-omic) biochemical origin, experimentally associated to RA. Starting from such collection we generated RA-related protein-protein interaction (PPI) networks (interactomes) based on experimental PPI data. Pharmacological treatment simulation, topological and functional analyses were further run to gain insight into the proteins most affected by therapy and by multi-omic modeling.

Results: Simulation on the administration of MTX results in the activation of expected (apoptosis) and adverse (nitrogenous metabolism alteration) effects. Growth factor receptor-bound protein 2 (GRB2) and Interleukin-1 Receptor Associated Kinase-4 (IRAK4, already an RA target) emerge as relevant nodes. The former controls the activation of inflammatory, proliferative and degenerative pathways in host and pathogens. The latter controls immune alterations and blocks innate response to pathogens.

Conclusions: This multi-omic map properly recollects in a single analytical picture known, yet complex, information like the adverse/side effects of MTX, and provides a reliable platform for in silico hypothesis testing or recommendation on novel therapies. These results can support the development of RA translational research in the design of validation experiments and clinical trials, as such we identify GRB2 as a robust potential new target for RA for its ability to control both synovial degeneracy and dysbiosis, and, conversely, warn on the usage of IRAK4-inhibitors recently promoted, as this involves potential adverse effects in the form of impaired innate response to pathogens.

Suppression of experimental arthritis with self-assembling glycol-split heparin nanoparticles via inhibition of TLR4-NF-κB signaling

It has been recently shown that Toll-like receptor4 mediated nuclear factor κB (TLR4-NF-κB) signaling plays a critical role in the pathogenesis of rheumatoid arthritis mediated by pro-inflammatory cytokines in arthritic synovium. Here we evaluate the therapeutic potential of glycol-split non-anticoagulant heparin/d-erythro-sphingosine nanoparticles (NAHNPs), which have shown strong inhibitory effect against TLR4 induced inflammation, in an experimental arthritis model. NAHNP significantly inhibited the production of pro-inflammatory cytokines such as TNF-α, IL-6 and IL-1β in lipopolysaccharide (LPS)-induced primary mouse macrophages and DC2.4 dendritic cell line. The nanoparticles were administered to type II collagen-induced arthritis (CIA) mice by intraarticular injections once per day starting from onset of the disease symptoms. Treatment with NAHNP had a potent suppressive effect in CIA mice, observed with a decrease in arthritis score and footpad swelling. The animals treated with NAHNP significantly reduced levels of IgG1 and IgG2a antibodies against bovine type II collagen. Levels of proinflammatory cytokines--e.g., TNF-α, IL-6 and IL-1β in knee joints and sera were significantly inhibited compared to control mice. Moreover, nuclear localization of RelA in knee joints was significantly inhibited in NAHNP treatment, indicating down-regulation of the NF-κB signaling pathway. In addition, histological examination revealed significant suppression of inflammatory cell infiltration, joint destruction and synovial proliferation in synovium compared with control mice. These results suggest that selective inhibition of TLR4-NF-κB signaling with lipid modified heparin derivatives composited to nanostructures provides an effective therapeutic approach to inhibit chronic inflammation in an animal model of rheumatoid arthritis.

Maternally sequestered therapeutic polypeptides - a new approach for the management of preeclampsia

The last several decades have seen intensive research into the molecular mechanisms underlying the symptoms of preeclampsia. While the underlying cause of preeclampsia is believed to be defective placental development and resulting placental ischemia, it is only recently that the links between the ischemic placenta and maternal symptomatic manifestation have been elucidated. Several different pathways have been implicated in the development of the disorder; most notably production of the anti-angiogenic protein sFlt-1, induction of auto-immunity and inflammation, and production of reactive oxygen species. While the molecular mechanisms are becoming clearer, translating that knowledge into effective therapeutics has proven elusive. Here we describe a number of peptide based therapies we have developed to target theses pathways, and which are currently being tested in preclinical models. These therapeutics are based on a synthetic polymeric carrier elastin-like polypeptide (ELP), which can be synthesized in various sequences and sizes to stabilize the therapeutic peptide and avoid crossing the placental interface. This prevents fetal exposure and potential developmental effects. The therapeutics designed will target known pathogenic pathways, and the ELP carrier could prove to be a versatile delivery system for administration of a variety of therapeutics during pregnancy.

A novel inhibitor of I-kappaB kinase beta ameliorates experimental arthritis through downregulation of proinflammatory cytokines in arthritic joints

Inhibitor of kappaB (IκB) kinase beta (IKKβ) plays a critical role in nuclear factor-kappaB (NF-κB) activation and production of proinflammatory cytokines in various inflammatory diseases including rheumatoid arthritis. We previously reported a novel IKKβ inhibitor Compound D, 4-[6-(cyclobutylamino)imidazo[1,2-b]pyridazin-3-yl]-2-fluoro-N-{[(2S,4R)-4-fluoropyrrolidin-2-yl]methyl}benzamide, which is efficacious in experimental arthritis models. In the present study, we characterized the pharmacological properties of Compound D and investigated the mechanisms of the anti-arthritic effect. Compound D inhibited IKKβ kinase activity with 160-fold selectivity against IKKα. The cellular analyses revealed that Compound D selectively blocked NF-κB promoter activity among major cellular signaling pathways, such as the activator protein-1 pathway, consistent with inhibition of the NF-κB signaling pathway including phosphorylation of IκBα. In addition, Compound D inhibited NF-κB-driven production of tumor necrosis factor alpha (TNFα) and interleukin-6 comparably. The correlation between inhibitory effect on TNFα production and plasma concentration of the compound was observed in vivo. Consecutive administration of Compound D decreased gene expression of proinflammatory cytokines and inflammatory mediators in the paws of arthritic mice with attenuation of paw swelling. Notably, Compound D was rapidly distributed to the arthritic paws, rather than healthy paws, and where it decreased the gene expression of proinflammatory cytokines by a single oral administration. Furthermore, Compound D completely inhibited arthritis progression even when treatment occurred after disease development. These data suggest that the downregulation of proinflammatory cytokines in local inflamed joints is one of the mechanisms underlying the anti-arthritic effect of the IKKβ inhibitor, Compound D.

Cellular adhesion gene SELP is associated with rheumatoid arthritis and displays differential allelic expression

In rheumatoid arthritis (RA), a key event is infiltration of inflammatory immune cells into the synovial lining, possibly aggravated by dysregulation of cellular adhesion molecules. Therefore, single nucleotide polymorphisms of 14 genes involved in cellular adhesion processes (CAST, ITGA4, ITGB1, ITGB2, PECAM1, PTEN, PTPN11, PTPRC, PXN, SELE, SELP, SRC, TYK2, and VCAM1) were analyzed for association with RA. Association analysis was performed consecutively in three European RA family sample groups (Nfamilies = 407). Additionally, we investigated differential allelic expression, a possible functional consequence of genetic variants. SELP (selectin P, CD62P) SNP-allele rs6136-T was associated with risk for RA in two RA family sample groups as well as in global analysis of all three groups (ptotal = 0.003). This allele was also expressed preferentially (p<10-6) with a two- fold average increase in regulated samples. Differential expression is supported by data from Genevar MuTHER (p1 = 0.004; p2 = 0.0177). Evidence for influence of rs6136 on transcription factor binding was also found in silico and in public datasets reporting in vitro data. In summary, we found SELP rs6136-T to be associated with RA and with increased expression of SELP mRNA. SELP is located on the surface of endothelial cells and crucial for recruitment, adhesion, and migration of inflammatory cells into the joint. Genetically determined increased SELP expression levels might thus be a novel additional risk factor for RA.

Markers of inflammation and oxidative stress studied in adjuvant-induced arthritis in the rat on systemic and local level affected by pinosylvin and methotrexate and their combination

Oxidative stress (OS) is important in the pathogenesis of autoimmune diseases such as rheumatoid arthritis (RA) and its experimental model--adjuvant arthritis (AA). Antioxidants are scarcely studied in autoimmunity, and future analyses are needed to assess its effects in ameliorating these diseases. Although there are studies about antioxidants effects on the course of RA, their role in combination therapy has not yet been studied in detail, especially on extra-articular manifestations of AA. During the 28-d administration of pinosylvin (PIN) in monotherapy and in combination with methotrexate (MTX) to AA rats, we evaluated the impact of the treatment on selected parameters. The experiment included: healthy controls, untreated AA, AA administered 50 mg/kg b.w. of PIN daily p.o., AA administered 0.4 mg/kg b.w. of MTX twice weekly p.o. and AA treated with a combination of PIN+MTX. AA was monitored using: hind paw volume, C-reactive protein, monocyte chemotactic protein-1 (MCP-1), thiobarbituric acid reactive substances (TBARS) and F2-isoprostanes in plasma, γ-glutamyltransferase activity in spleen, activity of lipoxygenase (LOX) in lung, heme oxygenase-1 (HO-1) and nuclear factor kappa B (NF-κB) in liver and lung. PIN monotherapy significantly improved the activation of NF-κB in liver and lung, HO-1 expression and activity of LOX in the lung, MCP-1 levels in plasma (on 14th d) and plasmatic levels of F2-isoprostanes. An important contribution of PIN to MTX effect was the reduction of OS (an increase of HO-1 expression in lung and reduction of plasmatic TBARS) and decrease of LOX activity in the lung.

Anti-inflammatory effects of sargachromenol-rich ethanolic extract of Myagropsis myagroides on lipopolysaccharide-stimulated BV-2 cells

BACKGROUND

Excessive pro-inflammatory cytokine production from activated microglia contributes to neurodegenerative diseases, thus, microglial inactivation may delay the progress of neurodegeneration by attenuating the neuroinflammation. Among 5 selected brown algae, we found the highest antioxidant and anti-neuroinflammatory activities from Myagropsis myagroides ethanolic extract (MME) in lipopolysaccharide (LPS)-stimulated BV-2 cells.

METHODS

The levels of nitric oxide (NO), prostaglandin E2 (PGE2), and pro-inflammatory cytokines were measured by Griess assay and enzyme linked immunesorbent assay. The levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), mitogen-activated protein kinases (MAPKs), and Akt were measured using Western blot. Nuclear translocation and transcriptional activation of nuclear factor-κB (NF-κB) were determined by immunefluorescence and reporter gene assay, respectively.

RESULTS

MME inhibited the expression of iNOS and COX-2 at mRNA and protein levels, resulting in reduction of NO and PGE2 production. As a result, pro-inflammatory cytokines were reduced by MME. MME also inhibited the activation and translocation of NF-κB by preventing inhibitor κB-α (IκB-α) degradation. Moreover, MME inhibited the phosphorylation of extracellular signal regulated kinases (ERKs) and c-Jun N-terminal kinases (JNKs). Main anti-inflammatory compound in MME was identified as sargachromenol by NMR spectroscopy.

CONCLUSIONS

These results indicate that the anti-inflammatory effect of sargachromenol-rich MME on LPS-stimulated microglia is mainly regulated by the inhibition of IκB-α/NF-κB and ERK/JNK pathways.

Novel insights into the regulatory architecture of CD4+ T cells in rheumatoid arthritis

Rheumatoid arthritis (RA) is the most frequent autoimmune chronic inflammatory disease of the joints and it is characterized by the inflammation of the synovial membrane and the subsequent destruction of the joints. In RA, CD4+ T cells are the main drivers of disease initiation and the perpetuation of the damaging inflammatory process. To date, however, the genetic regulatory mechanisms of CD4+ T cells associated with RA etiology are poorly understood. The genome-wide analysis of expression quantitative trait loci (eQTL) in disease-relevant cell types is a recent genomic integration approach that is providing significant insights into the genetic regulatory mechanisms of many human pathologies. The objective of the present study was to analyze, for the first time, the genome-wide genetic regulatory mechanisms associated with the gene expression of CD4+ T cells in RA. Whole genome gene expression profiling of CD4+ T cells and the genome-wide genotyping (598,258 SNPs) of 29 RA patients with an active disease were performed. In order to avoid the excessive burden of multiple testing associated with genome-wide trans-eQTL analysis, we developed and implemented a novel systems genetics approach. Finally, we compared the genomic regulation pattern of CD4+ T cells in RA with the genomic regulation observed in reference lymphoblastoid cell lines (LCLs). We identified a genome-wide significant cis-eQTL associated with the expression of FAM66C gene (P = 6.51e−9). Using our new systems genetics approach we identified six statistically significant trans-eQTLs associated with the expression of KIAA0101 (P<7.4e−8) and BIRC5 (P = 5.35e−8) genes. Finally, comparing the genomic regulation profiles between RA CD4+ T cells and control LCLs we found 20 genes showing differential regulatory patterns between both cell types. The present genome-wide eQTL analysis has identified new genetic regulatory elements that are key to the activity of CD4+ T cells in RA.

Activation of spinal NF-κB/p65 contributes to peripheral inflammation and hyperalgesia in rat adjuvant-induced arthritis

OBJECTIVE

It is known that noxious stimuli from inflamed tissue may increase the excitability of spinal dorsal horn neurons (a process known as central sensitization), which can signal back and contribute to peripheral inflammation. However, the underlying mechanisms have yet to be fully defined. A number of recent studies have indicated that spinal NF-κB/p65 is involved in central sensitization, as well as pain-related behavior. Thus, the aim of this study was to determine whether NF-κB/p65 can facilitate a peripheral inflammatory response in rat adjuvant-induced arthritis (AIA).

METHODS

Lentiviral vectors encoding short hairpin RNAs that target NF-κB/p65 (LV-shNF-κB/p65) were constructed for gene silencing. The spines of rats with AIA were injected with LV-shNF-κB/p65 on day 3 or day 10 after treatment with Freund's complete adjuvant (CFA). During an observation period of 20 days, pain-related behavior, paw swelling, and joint histopathologic changes were evaluated. Moreover, the expression levels of spinal tumor necrosis factor α (TNFα), interleukin-1β (IL-1β), and cyclooxygenase 2 (COX-2) were assessed on day 14 after CFA treatment.

RESULTS

The presence of peripheral inflammation in rats with AIA induced an increase in NF-κB/p65 expression in the spinal cord, mainly in the dorsal horn neurons and astrocytes. Delivery of LV-shNF-κB/p65 to the spinal cord knocked down the expression of NF-κB/p65 and significantly attenuated hyperalgesia, paw edema, and joint destruction. In addition, spinal delivery of LV-shNF-κB/p65 reduced the overexpression of spinal TNFα, IL-1β, and COX-2.

CONCLUSION

These findings indicate that spinal NF-κB/p65 plays an important role in the initiation and development of both peripheral inflammation and hyperalgesia. Thus, inhibition of spinal NF-κB/p65 expression may provide a potential treatment to manage painful inflammatory disorders.

Electroacupuncture exerts an anti-inflammatory effect in a rat tissue chamber model of inflammation via suppression of NF-κB activation

OBJECTIVE

Electroacupuncture (EA) has beneficial effects in patients with various inflammatory diseases. However, the underlying mechanism remains unclear. As the kappa B inhibitor/nuclear factor-kappa B (IκB/NF-κB) pathway exerts a pivotal role in the mammalian immune response, we examined the involvement of the IκB/NF-κB pathway in EA-induced anti-inflammation.

METHODS

Ninety tissue chamber implanted rats were randomly divided into control (C), model (M) and EA (E) groups. Physiological saline and human recombinant interleukin-1β (hr IL-1β) were injected into the rats in groups C and M, respectively, and EA treatment was applied to the rats in group E after IL-1β injection. Nuclear staining of p65 (a subunit of NF-κB) was quantified in the exudate cells by immunohistochemical analysis and IκBα expression in the cytoplasm was quantified by western blot analysis.

RESULTS

Our results showed that, compared with group C, the percentage of cells with nuclear-localised p65 was increased in group M by 71.3%, 50.7% and 33.1% at 1, 5 and 24 h time points (p<0.01), respectively. This increase was fully inhibited in group E at 5 and 24 h time points (p<0.01). The expression of IκBα was stably enhanced in group M (p<0.05) during the test period. Compared with group M, greater expression of IκBα in group E was only observed at the 1 h time point (p<0.01).

CONCLUSIONS

Collectively, our data suggest that EA inhibits the nuclear translocation of p65 and increases the expression of IκBα, which leads to the suppression of NF-κB activation in a rat tissue chamber model of inflammation.

Gallium nitrate ameliorates type II collagen-induced arthritis in mice

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease. Gallium nitrate has been reported to reserve immunosuppressive activities. Therefore, we assessed the therapeutic effects of gallium nitrate in the mouse model of developed type II collagen-induced arthritis (CIA). CIA was induced by bovine type II collagen with Complete Freund's adjuvant. CIA mice were intraperitoneally treated from day 36 to day 49 after immunization with 3.5mg/kg/day, 7mg/kg/day gallium nitrate or vehicle. Gallium nitrate ameliorated the progression of mice with CIA. The clinical symptoms of collagen-induced arthritis did not progress after treatment with gallium nitrate. Gallium nitrate inhibited the increase of CD4(+) T cell populations (p<0.05) and also inhibited the type II collagen-specific IgG2a-isotype autoantibodies (p<0.05). Gallium nitrate reduced the serum levels of TNF-α, IL-6 and IFN-γ (p<0.05) and the mRNA expression levels of these cytokine and MMPs (MMP2 and MMP9) in joint tissues. Western blotting of members of the NF-κB signaling pathway revealed that gallium nitrate inhibits the activation of NF-κB by blocking IκB degradation. These data suggest that gallium nitrate is a potential therapeutic agent for autoimmune inflammatory arthritis through its inhibition of the NF-κB pathway, and these results may help to elucidate gallium nitrate-mediated mechanisms of immunosuppression in patients with RA.

Genistein suppresses tumor necrosis factor α-induced inflammation via modulating reactive oxygen species/Akt/nuclear factor κB and adenosine monophosphate-activated protein kinase signal pathways in human synoviocyte MH7A cells

Aims

Genistein, an isoflavone derivative found in soy, is known as a promising treatment for rheumatoid arthritis (RA). However, the detailed molecular mechanism of genistein in suppression of proinflammatory cytokine production remains ambiguous. The aim of this work was to evaluate the signal pathway by which genistein modulates inflammatory cytokine expression.

Materials and methods

MH7A cells were stimulated with tumor necrosis factor (TNF)-α and incubated with genistein, and interleukin (IL)-1β, IL-6, and IL-8 production was measured by enzyme-linked immunosorbent assay. Nuclear translocation of nuclear factor (NF)-κB was measured by a confocal fluorescence microscopy. The intracellular accumulation of reactive oxygen species (ROS) was monitored using the fluorescent probe 5-6-chloromethyl-2′,7′-dichlorodihydrofluorescein diacetate. Signal-transduction protein expression was measured by Western blot.

Results

Genistein decreased the secretion of IL-1β, IL-6, and IL-8 from TNF-α-stimulated MH7A cells in a dose-dependent manner. Genistein prevented TNF-α-induced NF-κB translocation as well as phosphorylation of IκB kinase-α/β and IκBα, and also suppressed TNF-α-induced AMPK inhibition. The production of IL-1β, IL-6, and IL-8 induced by TNF-α was decreased by the phosphatidylinositol-3 kinase inhibitor LY294002, suggesting that inhibition of Akt activation might inhibit IL-1β, IL-6, and IL-8 production induced by TNF-α. In addition, we also found that pretreatment with the adenosine monophosphate-activated protein kinase (AMPK) agonist 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside obviously inhibited TNF-α-induced proinflammatory cytokine production. These observations suggest that the inhibitory effect of genistein on TNF-α-induced proinflammatory cytokine production is dependent on AMPK activation.

Conclusion

These findings indicate that genistein suppressed TNF-α-induced inflammation by inhibiting the ROS/Akt/NF-κB pathway and promoting AMPK activation in MH7A cells.

Swertiamarin attenuates inflammation mediators via modulating NF-κB/I κB and JAK2/STAT3 transcription factors in adjuvant induced arthritis

Rheumatoid arthritis (RA) is an autoimmune and chronic inflammatory disease that leads to pannus formation followed by severe joint destruction, characterized by synovial hyperplasia, inflammation and angiogenesis. Swertiamarin is a secoiridoid glycoside that is used as an anti-inflammatory compound, mainly found in Enicostema axillare (Lam) A. Raynal, a medicinal plant used in Indian system of traditional medicine. In the present study, the effect of swertiamarin was evlauated in experimental adjuvant arthritis animal model by the estimation of biochemical (paw thickness, lysosomal enzymes, and urinary degradative products) parameters, proinflammatory cytokines and enzymes along with histopathological and radiographic observations. The proteins of phosphorylated NF-κB/IκB and JAK2/STAT3 transcription factors were also quantified from experimental animals as well as LPS induced RAW 264.7 macrophage cells. In in silico analysis, swertiamarin was docked with proinflammatory enzymes to confirm its potential. The administration of swertiamarin (2, 5, 10mg/kg bw) significantly (P⩽0.05) inhibited the levels of paw thickness, lysosomal enzymes and increased the body weight of experimental animals in a dose dependent manner. In molecular analysis, the treatment decreased the release of proinflammatory cytokines (IL1, TNF, IL-6) and proangiogenic enzymes (MMPs, iNOS, PGE2, PPARγ and COX-2); and also significantly (P⩽0.05) increased the levels of antiinflammatory proteins (IL-10, IL-4) when compared to the disease groups. The swertiamarin treatment significantly (P⩽0.05) inhibited the release of NF-κB p65, p-IκBα, p-JAK2 and p-STAT3 signaling proteins levels on both experimental animals and LPS induced cells. Histopathological and radiological analysis evidenced the curative effect of swertiamarin on bone destruction. The docking studies of swertiamarin on proinflammatory enzymes supported the results from the in vivo experiments. Thus the swertiamarin inhibited the development of arthritis by modulating NF-κB/IκB and JAK2/STAT3 signaling. These findings suggested that swertiamarin acted as an anti-rheumatic agent.