Anti-cytokine therapy in chronic destructive arthritis

Interleukin-1β activated c-FOS transcription factor binds preferentially to a specific allele of the matrix metalloproteinase-13 promoter and increases susceptibility to endometriosis

Endometriosis is a benign gynecological condition characterized by increased growth, inflammation, invasion, and angiogenesis, partly regulated by a class of enzymes called matrix metalloproteinases (MMPs). The importance of a few MMPs, e.g., MMP-9, -3, and -7 has been studied in endometriosis progression. Although MMP-13 plays an essential role in bone regeneration and cancer, no report has been found on the part of MMP-13 and endometriosis progression. We found the upregulation of MMP-13 expression and activity in patients having endometriosis in the eastern Indian population. In addition, the -77A/G polymorphism of the MMP13 promoter (rs: 2252070) is associated with regulating transcription and subsequent susceptibility to disease. In eastern Indian case-control groups, the effect of the -77A/G single-nucleotide polymorphism on MMP13 promoter activity and its relationship with endometriosis susceptibility was studied. The AG genotype was shown to be more predisposed to endometriosis risk than the GG genotype (p: 0.02; odds ratio [OR]: 1.65, 95% confidence interval [CI]: 1.10-2.49), also AG genotype was more frequent in late-stage patients compared to early-stage (p: 0.03, OR: 2.0, 95% CI: 1.09-3.66). Furthermore, the MMP13 gene levels were greater in AA compared to GG individuals. Additionally, MMP13 promoter-reporter experiments in cultured endometrial epithelial cells and in silico analyses both demonstrated increased transcriptional activity near the G to A transition under basal/IL-1β -induced/c-FOS overexpressed condition. Overall, c-FOS tighter binding to the A allele-carrying promoter enhances MMP13 transcription, which is further amplified by IL-1β due to increased c-FOS phosphorylation, promoting MMP-13 production and endometriosis risk.

Cartilage tissue engineering: From proinflammatory and anti‑inflammatory cytokines to osteoarthritis treatments (Review)

Osteoarthritis (OA), one of the most common joint diseases, is characterized by fibrosis, rhagadia, ulcers and attrition of articular cartilage due to a number of factors. The etiology of OA remains unclear, but its occurrence has been associated with age, obesity, inflammation, trauma and genetic factors. Inflammatory cytokines are crucial for the occurrence and progression of OA. The intra-articular proinflammatory and anti-inflammatory cytokines jointly maintain a dynamic balance, in accordance with the physiological metabolism of articular cartilage. However, dynamic imbalance between proinflammatory and anti-inflammatory cytokines can cause abnormal metabolism in knee articular cartilage, which leads to deformation, loss and abnormal regeneration, and ultimately destroys the normal structure of the knee joint. The ability of articular cartilage to self-repair once damaged is limited, due to its inability to obtain nutrients from blood vessels, nerves and lymphatic vessels, as well as limitations in the extracellular matrix. There are several disadvantages inherent to conventional repair methods, while cartilage tissue engineering (CTE), which combines proinflammatory and anti-inflammatory cytokines, offers a new therapeutic approach for OA. The aim of the present review was to examine the proinflammatory factors implicated in OA, including IL-1β, TNF-α, IL-6, IL-15, IL-17 and IL-18, as well as the key anti-inflammatory factors reducing OA-related articular damage, including IL-4, insulin-like growth factor and TGF-β. The predominance of proinflammatory over anti-inflammatory cytokine effects ultimately leads to the development of OA. CTE, which employs mesenchymal stem cells and scaffolding technology, may prevent OA by maintaining the homeostasis of pro- and anti-inflammatory factors.

Pharmacomicrobiology of Methotrexate in Rheumatoid Arthritis: Gut Microbiome as Predictor of Therapeutic Response

Rheumatoid arthritis (RA) is a disabling autoimmune disease with invasive arthritis as the main manifestation and synovitis as the basic pathological change, which can cause progressive destruction of articular cartilage and bone, ultimately leading to joint deformity and loss of function. Since its introduction in the 1980s and its widespread use in the treatment of RA, low-dose methotrexate (MTX) therapy has dramatically changed the course and outcome of RA treatment. The clinical use of this drug will be more rational with a better understanding of the pharmacology, anti-inflammatory mechanisms of action and adverse reaction about it. At present, the current clinical status of newly diagnosed RA is that MTX is initiated first regardless of the patients’ suitability. But up to 50% of patients could not reach adequate clinical efficacy or have severe adverse events. Prior to drug initiation, a prognostic tool for treatment response is lacking, which is thought to be the most important cause of the situation. A growing body of studies have shown that differences in microbial metagenomes (including bacterial strains, genes, enzymes, proteins and/or metabolites) in the gastrointestinal tract of RA patients may at least partially determine their bioavailability and/or subsequent response to MTX. Based on this, some researchers established a random forest model to predict whether different RA patients (with different gut microbiome) would respond to MTX. Of course, MTX, in turn, alters the gut microbiome in a dose-dependent manner. The interaction between drugs and microorganisms is called pharmacomicrobiology. Then, the concept of precision medicine has been raised. In this view, we summarize the characteristics and anti-inflammatory mechanisms of MTX and highlight the interaction between gut microbiome and MTX aiming to find the optimal treatment for patients according to individual differences and discuss the application and prospect of precision medicine.

Joint hemorrhage accelerates cartilage degeneration in a rat immobilized knee model

Background

Joint hemorrhage is caused by trauma, ligament reconstruction surgery, and bleeding disorders such as hemophilia. Recurrence of hemorrhage in the joint space induces hemosiderotic synovitis and oxidative stress, resulting in both articular cartilage degeneration and arthropathy. Joint immobilization is a common treatment option for articular fractures accompanied by joint hemorrhage. Although joint hemorrhage has negative effects on the articular cartilage, there is no consensus on whether a reduction in joint hemorrhage would effectively prevent articular cartilage degeneration. The purpose of this study was to investigate the effect of joint hemorrhage combined with joint immobilization on articular cartilage degeneration in a rat immobilized knee model.

Methods

The knee joints of adult male rats were immobilized at the flexion using an internal fixator from 3 days to 8 weeks. The rats were randomly divided into the following groups: immobilized blood injection (Im-B) and immobilized-normal saline injection (Im-NS) groups. The cartilage was evaluated in two areas (contact and non-contact areas). The cartilage was used to assess chondrocyte count, Modified Mankin score, and cartilage thickness. The total RNA was extracted from the cartilage in both areas, and the expression of metalloproteinase (MMP)-8, MMP-13, interleukin (IL)-1β, and tumor necrosis factor (TNF)-α was measured by quantitative real-time polymerase chain reaction.

Results

The number of chondrocytes in the Im-B group significantly decreased in both areas, compared with that in the Im-NS group. Modified Mankin score from 4 to 8 weeks of the Im-B group was significantly higher than that of the Im-NS group only in the contact area. The expression of MMP-8 and MMP-13 from 2 to 4 weeks and TNF-α from 2 to 8 weeks significantly increased in the Im-B group compared with those in the Im-NS group, but there was no significant difference in IL-1β expression.

Conclusions

The results showed that joint hemorrhage exacerbated immobilization-induced articular cartilage degeneration. Drainage of a joint hemorrhage or avoidance of loading may help prevent cartilage degeneration during joint immobilization with a hemorrhage.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-020-03795-0.

Molecular mechanism of action and pharmacokinetic properties of methotrexate

Since its discovery in 1945, methotrexate has become a standard therapy for number of diseases, including oncological, inflammatory and pulmonary ones. Major physiological interactions of methotrexate include folate pathway, adenosine, prostaglandins, leukotrienes and cytokines. Methotrexate is used in treatment of pulmonary sarcoidosis as a second line therapy and is drug of choice in patients who are not candidates for corticosteroid therapy, with recommended starting weekly dose of 5-15 mg. Number of studies dealt with methotrexate use in rheumatoid arthritis and oncological patients. Authors are conducting research on oral methotrexate use and pharmacokinetics in chronic sarcoidosis patients and have performed literature research to better understand molecular mechanisms of methotrexate action as well as high level pharmacokinetic considerations. Polyglutamation of methotrexate affects its pharmacokinetic and pharmacodynamic properties and prolongs its effect. Bile excretion plays significant role due to extensive enterohepatic recirculation, although majority of methotrexate is excreted through urine. Better understanding of its pharmacokinetic properties in sarcoidosis patients warrant optimizing therapy when corticosteroids are contraindicated in these patients.

The effect of Ganoderma lucidum extract on immunological function and identify its anti-tumor immunostimulatory activity based on the biological network

Ganoderma lucidum extract (GLE) has shown positive effects for tumor treatment. However, the molecular mechanism of GLE treatment is unknown. In this study, a Hepa1-6-bearing C57 BL/6 mouse model was established to explore the anti-tumor and immunostimulatory activity of GLE treatment. The results showed that GLE effectively inhibited tumor growth without hepatic/renal toxicity and bone marrow suppression, and might enhancing immunological function. Based on the mRNA profiles of GLE treated and untreated mice, 302 differentially expressed (DE) mRNAs were identified and 6 kernel mRNAs were identified from the established protein-protein interaction (PPI) network. Quantitative RT-PCR and western-blot analysis indicated that 6 mRNAs have had statistically significant differences between the GLE treated and untreated mice. Furthermore, four kernel pathways were isolated from the KEGG-Target network, including the Jak-STAT signaling pathway, T cell receptor signaling pathway, PI3K-Akt signaling pathway, and cytokine-cytokine receptor interaction. Western-blot and cytokine detection results demonstrated that GLE suppressed growth and proliferation of tumors by the Jak-STAT signaling pathway, T cell receptor signaling pathway and PI3K-Akt signaling pathway, but also regulated the expression levels of serum immune cytokines and improved the anti-tumor immunostimulatory activity.

IL-20 bone diseases involvement and therapeutic target potential

BACKGROUND

Millions of people around the world suffer from bone disorders, likes osteoporosis, rheumatoid arthritis (RA), and cancer-induced osteolysis. In general, the bone remodeling balance is determined by osteoclasts and osteoblasts, respectively responsible for bone resorption and bone formation. Excessive inflammation disturbs the activities of these two kinds of cells, typically resulting in the bone loss.

MAIN BODY

IL-20 is emerging as a potent angiogenic, chemotactic, and proinflammatory cytokine related to several chronic inflammatory disorders likes psoriasis, atherosclerosis, cancer, liver fibrosis, and RA. IL-20 has an important role in the regulation of osteoclastogenesis and osteoblastogenesis and is upregulated in several bone-related diseases. The anti-IL-20 monoclonal antibody treatment has a therapeutic potential in several experimental disease models including ovariectomy-induced osteoporosis, cancer-induced osteolysis, and bone fracture.

CONCLUSION

This review article provides an overview describing the IL-20's biological functions in the common bone disorders and thus providing a novel therapeutic strategy in the future.

A Single Codon Optimization Enhances Recombinant Human TNF-α Vaccine Expression in Escherichia coli

As a proinflammatory cytokine, tumor necrosis factor-alpha (TNF-α) plays a pivotal role in various autoimmune diseases such as rheumatoid arthritis (RA). Thus, TNF-α has been defined as a therapeutic target for RA. Although some TNF-α antagonists including neutralizing monoclonal antibodies and soluble receptors have been approved to be successful in attenuating symptoms in patients suffering from RA, the long-term use of these passive immunization reagents could cause some problems like a variable degree of immunogenicity. In the present study, in order to wake up active immune responses of RA patients, we developed a recombinant TNF-α therapeutic vaccine (named mrTNF-PADRE) by coupling a 12-amino acid universal Pan HLA-DR Epitope (PADRE) to the protein. Codon optimization was performed to improve the secondary structure of mrTNF-PADRE mRNA to ensure its heterologous expression. As a result, a single codon synonymous mutation greatly elevated recombinant protein expression (about 30% of the total bacteria proteins) in E. coli as compared with the undetectable expression of the unoptimized gene. Although expressed as insoluble inclusion bodies (IBs), the vaccine can be effectively prepared with a purity of over 95% by IBs washing and one-step gel-infiltration chromatography. By this strategy, a stable yield of 5.2 mg purified mrTNF-PADRE per gram of cell paste could be obtained.

Hydroxysafflor yellow A inhibits IL-1β-induced release of IL-6, IL-8, and MMP-1 via suppression of ERK, NF-κB and AP-1 signaling in SW982 human synovial cells

Hydroxysafflor yellow A (HSYA), the main active ingredient in medical and edible dual purpose plant safflower, is reported to have multiple bioactivities. In the present study, the anti-inflammatory effects of HSYA and the underlying mechanisms were investigated in interleukin (IL)-1β-induced SW982 human synovial cells. The cells were pretreated with HSYA at various concentrations (2.5, 10 and 40 μM) followed by IL-1β (10 ng mL^-1) stimulation. HSYA significantly inhibited the expression of IL-6, IL-8 and matrix metalloproteinase (MMP)-1 in IL-1β-stimulated SW982 cells. HSYA also inhibited the phosphorylation of extracellular signal-regulated kinase (ERK), p65 and c-Jun. It also suppressed the degradation of IκBα and blocked p65 translocation into the nucleus. These results indicate that the inhibitory effects of HSYA on IL-1β-induced IL-6, IL-8 and MMP-1 release might be mediated via suppression of ERK, nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) signaling pathways. The present data support the potential role of HSYA as an effective therapeutic agent in osteoarthritis.

Nanomaterials in the Context of Type 2 Immune Responses-Fears and Potentials

The type 2 immune response is an adaptive immune program involved in defense against parasites, detoxification, and wound healing, but is predominantly known for its pathophysiological effects, manifesting as allergic disease. Engineered nanoparticles (NPs) are non-self entities that, to our knowledge, do not stimulate detrimental type 2 responses directly, but have the potential to modulate ongoing reactions in various ways, including the delivery of substances aiming at providing a therapeutic benefit. We review, here, the state of knowledge concerning the interaction of NPs with type 2 immune responses and highlight their potential as a multifunctional platform for therapeutic intervention.

K/BxN Serum-Transfer Arthritis as a Model for Human Inflammatory Arthritis

The K/BxN serum-transfer arthritis (STA) model is a murine model in which the immunological mechanisms occurring in rheumatoid arthritis (RA) and other arthritides can be studied. To induce K/BxN STA, serum from arthritic transgenic K/BxN mice is transferred to naive mice and manifestations of arthritis occur a few days later. The inflammatory response in the model is driven by autoantibodies against the ubiquitously expressed self-antigen, glucose-6-phosphate isomerase (G6PI), leading to the formation of immune complexes that drive the activation of different innate immune cells such as neutrophils, macrophages, and possibly mast cells. The pathogenesis further involves a range of immune mediators including cytokines, chemokines, complement factors, Toll-like receptors, Fc receptors, and integrins, as well as factors involved in pain and bone erosion. Hence, even though the K/BxN STA model mimics only the effector phase of RA, it still involves a wide range of relevant disease mediators. Additionally, as a murine model for arthritis, the K/BxN STA model has some obvious advantages. First, it has a rapid and robust onset of arthritis with 100% incidence in genetically identical animals. Second, it can be induced in a wide range of strain backgrounds and can therefore also be induced in gene-deficient strains to study the specific importance of disease mediators. Even though G6PI might not be an essential autoantigen, for example, in RA, the K/BxN STA model is a useful tool to understand how autoantibodies, in general, drive the progression of arthritis by interacting with downstream components of the innate immune system. Finally, the model has also proven useful as a model wherein arthritic pain can be studied. Taken together, these features make the K/BxN STA model a relevant one for RA, and it is a potentially valuable tool, especially for the preclinical screening of new therapeutic targets for RA and perhaps other forms of inflammatory arthritis. Here, we describe the molecular and cellular pathways in the development of K/BxN STA focusing on the recent advances in the understanding of the important mechanisms. Additionally, this review provides a comparison of the K/BxN STA model to some other arthritis models.

Extracts of Bauhinia championii (Benth.) Benth. attenuate the inflammatory response in a rat model of collagen-induced arthritis

Rheumatoid arthritis is considered a serious public health problem, which is commonly treated with traditional Chinese or herbal medicine. The present study evaluated the effects of Bauhinia championii (Benth.) Benth. extraction (BCBE) on a type II collagen-induced arthritis (CIA) rat model. Wistar rats with CIA received either 125 or 500 mg/kg BCBE, after which, paw swelling was markedly suppressed compared with in the model group. In addition, BCBE significantly ameliorated pathological joint alterations, including synovial hyperplasia, and cartilage and bone destruction. The protein and mRNA expression levels of interleukin (IL)-6, IL-8, tumor necrosis factor-α and nuclear factor-κB in synovial tissue were determined by immunohistochemical staining, western blot analysis and reverse transcription-polymerase chain reaction. The results demonstrated that the expression levels of these factors were significantly downregulated in the BCBE-treated group compared with in the model group. These results indicated that BCBE may exert an inhibitory effect on the CIA rat model, and its therapeutic potential is associated with its anti-inflammatory action.

Induction of human ADAMTS-2 gene expression by IL-1α is mediated by a multiple crosstalk of MEK/JNK and PI3K pathways in osteoblast like cells

Up-regulation of ADAMTS genes with proinflammatory cytokines is important for some pathological conditions such as osteoarthritis (OA) that is a disease based on ECM degradation in cartilage. IL-1α is a proinflammatory cytokine and important both to normal and pathophysiologic conditions in cartilage and bone. Effects of some proinflammatory cytokines such as TNF-α and IL-1β on the some members of ADAMTS family have been investigated in some chondrocyte tissues or cell lines. However the effect of the IL-1α on the expression of ADAMTS-2 and ADAMTS-3 gene expression in osteoblast like cell lines, remains unclear. Therefore, the aim of this study is to investigate the effect of IL-1α on ADAMTS-2 and ADAMTS-3 gene expression in osteoblast like cells, Saos-2 and MG-63. The present study, for the first time, demonstrated that IL-1α increases ADAMTS-2 and ADAMTS-3 gene expressions in both Saos-2 and MG-63 cells. Having correlation to mRNA induction, the upregulation of ADAMTS-2,-3 protein levels by IL-1α stimulation is also observed. The inhibition studies showed that this upregulation occurred at the level of transcription, and there was no effect of IL-1α on ADAMTS-2 mRNA half-life in Saos-2 cells. Transactivation potential of IL-1α on ADAMTS-2 promoter was investigated by transient transfection assay. Specifically, IL-1α strongly increased -658/+112 and -530/+112 ADAMTS-2 promoter constructs. Further, we analyzed signaling pathways involved in ADAMTS-2 induction. Pathway inhibition studies revealed that this upregulation depends on the activation of MEK, JNK and PI3K pathways. These findings suggested that IL-1α is a strong positive regulator of ADAMTS-2 and ADAMTS-3 expression. These findings would provide novel insight into the pathophysiology of OA.

Etanercept ameliorates inflammation and pain in a novel mono-arthritic multi-flare model of streptococcal cell wall induced arthritis

Background

The impact of anti-TNF, corticosteroid and analgesic therapy on inflammation and pain was evaluated in a novel mono-arthritic multi-flare rat Streptococcal Cell Wall (SCW) model using Etanercept, Dexamethasone and Buprenorphine.

Methods

Multiple flares of arthritis were induced with an intra-articular injection of SCW in the hind ankle on day 1, followed by intravenous challenges on days 21 and 42. Inflammation and pain were monitored in the hind paws. Cytokine profiling, cell phenotyping, bioluminescence imaging and histopathological evaluation were also performed.

Results

Local injection of SCW caused a rapid onset of inflammation and pain in the injected ankle which resolved within 4 days (Flare 1). Intravenous injection 20 days after sensitization resulted in an increase in ankle diameter and pain, which partially resolved in 8 days (Flare 2). The subsequent intra-venous injection in the same animals 14 days after resulted in a more chronic disease with inflammation and pain persisting over a period of 10 days (Flare 3). In Flare 2, therapeutic administration of Dexamethasone inhibited paw swelling (95%; P<0.001) and pain (55%; P<0.05). Therapeutic administration of Buprenorphine inhibited pain (80%; P<0.001) without affecting paw swelling (0%). Prophylactic administration of Etanercept in Flare 2 inhibited paw swelling (≥60%; P<0.001) and pain by ≥30%. Expression of IL-1β, IL-6, MCP-1 and CINC was reduced by >50% (P<0.001). Treatment with Etanercept in Flare 3 inhibited paw swelling by 60% (P<0.001) and pain by 25%. Prior treatment with Etanercept in Flare 2 followed by re-administration in Flare 3 led to a complete loss in the efficacy of Etanercept. Systemic exposure of Etanercept corroborated with lack of efficacy. Dexamethasone inhibited inflammation and pain in both Flares 2 and 3 (P<0.001).

Conclusions

We established a novel multi-flare SCW arthritis model enabling drug intervention in different stages of disease. We show for the first time the evaluation of inflammation and pain simultaneously in this model. Etanercept and Dexamethasone inhibited inflammation, pain and proinflammatory cytokines in this model. Taken together, this model facilitates the assessment of anti-rheumatic agents targeting inflammation and pain in the multiple flare paradigm and offers a powerful tool for drug discovery.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2474-15-409) contains supplementary material, which is available to authorized users.

Quantification of tumor necrosis factor-α and matrix metalloproteinases-3 in synovial fluid by a fiber-optic particle plasmon resonance sensor

The availability of techniques for sensitive detection of early stage osteoarthritis is critical for improving patient health. This study illustrates the feasibility of a fiber-optic particle plasmon resonance (FOPPR) sensor with gold nanoparticles on the unclad region of optical fiber probes for analysis of osteoarthritis biomarkers, tumor necrosis factor-α (TNF-α) and matrix metalloproteinases-3 (MMP-3). Results show that the sensor can achieve a refractive index resolution of 5.18 × 10⁻⁷ RIU and limits of detection for TNF-α and MMP-3 as low as 8.22 pg ml⁻¹ (0.48 pM) and 34.3 pg ml⁻¹ (1.56 pM), respectively. Additionally, the FOPPR sensor shows a good correlation in determining TNF-α and MMP-3 in synovial fluid with the clinically accepted enzyme-linked immunosorbent assay (ELISA) method. Finally, given the FOPPR sensor's nature of being low-cost, label-free, highly sensitive, real-time, simple-to-operate, the FOPPR sensor could offer potential to monitor biomarkers of various diseases, and provide an ideal technical tool for point-of-care diagnostics.

The multifaceted effects of polysaccharides isolated from Dendrobium huoshanense on immune functions with the induction of interleukin-1 receptor antagonist (IL-1ra) in monocytes

Dendrobium huoshanense is a valuable and versatile Chinese herbal medicine with the anecdotal claims of cancer prevention and anti-inflammation. However, its immunological activities are limited to in vitro studies on a few cytokines and immune cell functions. First, we investigated the effects of polysaccharides isolated from DH (DH-PS) on inducing a panel of cytokines/chemokines in mice in vivo and human in vitro. We found that DH polysaccharides (DH-PS) induced TH1, TH2, inflammatory cytokines and chemokines in mouse in vivo and human cells in vitro. Secondly, we demonstrated that DH-PS expanded mouse splenocytes in vivo including CD4⁺ T cells, CD8⁺ T cells, B cells, NK cells, NKT cells, monocytes/macrophages, granulocytes and regulatory T cells. Notably, DH-PS induced an anti-inflammatory molecule, IL-1ra, in mouse and human immune cells, especially monocytes. The serum level of IL-1ra elicited by the injection of DH-PS was over 10 folds of IL-1β, suggesting that DH-PS-induced anti-inflammatory activities might over-ride the inflammatory ones mediated by IL-1β. The signaling pathways of DH-PS-induced IL-1ra production was shown to involve ERK/ELK, p38 MAPK, PI3K and NFκB. Finally, we observed that IL-1ra level induced by DH-PS was significantly higher than that by F3, a polysaccharide extract isolated from another popular Chinese herbal medicine, Ganoderma lucidum. These results indicated that DH-PS might have potential applications for ameliorating IL-1-induced pathogenic conditions.

Anti-arthritic activity of ethanol extract of Fagopyrum cymosum with adjuvant-induced arthritis in rats

CONTEXT

Fagopyrum cymosum (Trey.) Meisn (Polygonaceae) (EFC) has long been used as a folk medicine to treat various ailments of the lung, dysentery and rheumatism in China.

OBJECTIVE

The present study evaluated the anti-arthritic effect of 95% ethanol extract of EFC (extract of Fagopyrum cymosum).

MATERIALS AND METHODS

The anti-arthritic activity was investigated by adjuvant arthritic (AA) rat model induced by Freund's complete adjuvant (FCA). The AA rats were randomly separated into different groups and then treated with EFC (40, 80 and 160 mg/kg) from day 7 to day 28 after immunization. Arthritis was evaluated by hind paw swelling, polyarthritis index, body weight and index of immune organs. In addition, the severity of arthritis in the knee joints was evaluated by histopathological and hemorheological examination. The levels of interleukin 1 (IL-1) and tumor necrosis factor alpha (TNF-α) in the serum were assessed by ELISA.

RESULTS

The high dose level of EFC (160 mg/kg) significantly suppressed the swelling of hind paw of AA rats (p < 0.01) and inhibited their body weight loss (p < 0.01). Based on histopathological examination, all EFC groups showed great amelioration compared with the model group. EFC (80 and 160 mg/kg) also decreased the plasma viscosity in different shear rates (p < 0.01). Moreover, EFC significantly reduced the production of IL-1 and TNF-α in the serum of AA (p < 0.01).

DISCUSSION AND CONCLUSION

This study provides a scientific basis for the claims that F. cymosum is effective in preventing and suppressing the development and progression of experimental arthritis, with reductions in inflammatory response.

In vitro and in vivo anti-inflammatory effects of 4-methoxy-5- hydroxycanthin-6-one, a natural alkaloid from Picrasma quassioides

In the present study, we evaluated the anti-inflammatory effect of 4-methoxy-5- hydroxycanthin-6-one (CAN), a natural alkaloid isolated from Picrasma quassioides. CAN significantly inhibited the production of NO and the release of TNF-α induced by LPS in macrophage RAW 264.7. Western blot showed that CAN can downregulate the expression of iNOS protein. After oral administration, CAN (3, 9, and 27 mg/kg) reduced the development of carrageenan-induced paw edema and complete Freund's adjuvant (CFA)-induced chronic arthritis in rats. The observed results indicated that pre-treatment with CAN might be an effective therapeutic intervention against inflammatory diseases including chronic arthritis.

A short DNA aptamer that recognizes TNFα and blocks its activity in vitro

Tumor necrosis factor-alpha (TNFα) is a pivotal component of the cytokine network linked to inflammatory diseases. Protein-based, TNFα inhibitors have proven to be clinically valuable. Here, we report the identification of short, single-stranded DNA aptamers that bind specifically to human TNFα. One such 25-base long aptamer, termed VR11, was shown to inhibit TNFα signaling as measured using NF-κB luciferase reporter assays. This aptamer bound specifically to TNFα with a dissociation constant of 7.0 ± 2.1 nM as measured by surface plasmon resonance (SPR) and showed no binding to TNFβ. Aptamer VR11 was also able to prevent TNFα-induced apoptosis as well as reduce nitric oxide (NO) production in cultured cells for up to 24 h. As well, VR11, which contains a GC rich region, did not raise an immune response when injected intraperitoneally into C57BL/6 mice when compared to a CpG oligodeoxynucleotide (ODN) control, a known TLR9 ligand. These studies suggest that VR11 may represent a simpler, synthetic scaffold than antibodies or protein domains upon which to derive nonimmunogenic oligonucleotide-based inhibitors of TNFα.

CC chemokine receptors and chronic inflammation--therapeutic opportunities and pharmacological challenges

Chemokines are a family of low molecular weight proteins with an essential role in leukocyte trafficking during both homeostasis and inflammation. The CC class of chemokines consists of at least 28 members (CCL1-28) that signal through 10 known chemokine receptors (CCR1-10). CC chemokine receptors are expressed predominantly by T cells and monocyte-macrophages, cell types associated predominantly with chronic inflammation occurring over weeks or years. Chronic inflammatory diseases including rheumatoid arthritis, atherosclerosis, and metabolic syndrome are characterized by continued leukocyte infiltration into the inflammatory site, driven in large part by excessive chemokine production. Over years or decades, persistent inflammation may lead to loss of tissue architecture and function, causing severe disability or, in the case of atherosclerosis, fatal outcomes such as myocardial infarction or stroke. Despite the existence of several clinical strategies for targeting chronic inflammation, these diseases remain significant causes of morbidity and mortality globally, with a concomitant economic impact. Thus, the development of novel therapeutic agents for the treatment of chronic inflammatory disease continues to be a priority. In this review we introduce CC chemokine receptors as critical mediators of chronic inflammatory responses and explore their potential role as pharmacological targets. We discuss functions of individual CC chemokine receptors based on in vitro pharmacological data as well as transgenic animal studies. Focusing on three key forms of chronic inflammation--rheumatoid arthritis, atherosclerosis, and metabolic syndrome--we describe the pathologic function of CC chemokine receptors and their possible relevance as therapeutic targets.

Effect of Bizhongxiao decoction and its dismantled formulae on IL-1 and TNF levels in collagen-induced arthritis in rat synovial joints

Background

Rheumatoid arthritis (RA), a chronic autoimmune disease, affects sufferers in many different ways. Treatment of this chronic condition is particularly challenging. Traditional Chinese Medicine (TCM) provides alternatives. Bizhongxiao decoction (BZX) is a TCM complex, which has been used clinically for many years to treat RA. The purpose of this study is to compare the effects of BZX decoction and its dismantled formulae on IL-1 and TNF-1 levels in rats with RA, and to elucidate its mechanism of action.

Methods

Ninety healthy normal female SD rats were randomly divided into six groups: normal (control), model, BZX decoction, and the three dismantled formulae (I: heat-clearing and detoxication, II: dissipating dampness, and III: blood circulation promotion). Apart from the normal (control) group, the rats in each group were injected subcutaneously with bovine type II collagen and complete Freund adjuvant to establish a collagen-induced arthritis model, so that inhibition of foot swelling in the rats by BZX decoction and its dismantled formulae could be observed. Immunohistochemistry was used to assess the levels of the inflammatory cytokines IL-1 and TNF in synovial joints at various time points.

Results

Twenty-one days after the model was established, the levels of TNF and IL-1 were significantly higher in the model group, BZX decoction group and dismantled formula groups I, II and III than in the normal controls (P < 0.05). The levels of these cytokines were significantly higher in the model group than the BZX decoction or the three dismantled formula groups (P <0.01). At longer times, the TNF and IL-1 levels in model group rose gradually; those in the BZX decoction and dismantled formula groups were gradually reduced. The cytokine levels in the BZX decoction group were lower than in the three dismantled formula groups and continued to decline.

Conclusions

BZX decoction and the three dismantled formulae examined down-regulated the inflammatory factors IL-1 and TNF in collagen-induced arthritis rat models, but BZX exerted the strongest effect.

Efficacy of concurrent administration of cilostazol and methotrexate in rheumatoid arthritis: pharmacologic and clinical significance

AIMS

This study aimed to assess the beneficial effects of the concurrent administration of cilostazol and methotrexate (MTX) on the synovial fibroblasts obtained from patients with rheumatoid arthritis (RA), and in a mouse model of collagen-induced arthritis (CIA).

MAIN METHODS

Production of TNF-α, IL-1β, IL-6 and MCP-1 on synovial fibroblasts from RA patients was determined by RT-PCR. Cell proliferation, viability and apoptosis were measured. Anti-arthritic effects were evaluated in CIA mice.

KEY FINDING

Concurrent use of cilostazol and MTX effectively suppressed proliferation and cell viability associated with enhanced apoptosis of synovial fibroblasts and significantly suppressed cytokine production, including TNF-α, IL-1β, IL-6, and MCP-1 in an additive manner. In line with these findings, LPS-induced increased expression of NURR1 mRNA and protein were suppressed by cilostazol and MTX in accordance with suppression of NF-κB p65 activity. These suppressed effects were reversed by KT5720 (cAMP-protein kinase inhibitor) and ZM 241385 (A(2A) receptor antagonist), respectively. In CIA mice, treatment with cilostazol, MTX and their combination significantly decreased clinical signs with improvement of histopathological status in the paw of mice, accompanied by reduced serum cytokine levels. Likewise, following concurrent administration, CD68 (+)-cell recruitment, proteoglycan depletion and osteoclast formation were significantly suppressed in association with repressed RANKL expression in the joints of CIA mice.

SIGNIFICANCE

In conclusion, a combination of cilostazol and MTX may provide an effective therapeutic strategy for the suppression of inflammation and the prevention of joint damage in RA via activation of the cAMP-dependent protein kinase in the synovial fibroblasts.

The anti-arthritic and anti-oxidative effect of NBD (6-nitro-1,3-benzodioxane) in adjuvant-induced arthritis (AIA) in rats

OBJECTIVES

The present study evaluated the anti-arthritic and anti-oxidative effects of 6-nitro-1,3-benzodioxane in the adjuvant-induced arthritis model in rats.

METHODS

Arthritis was induced in female rats by intradermal injection of MT37Ra. Arthritis was evaluated by arthritic score, body weight loss, paw volume measurement, and histological changes. The plantar test was used to evaluate the effect of NBD on hyperalgesia.

RESULTS

The hyperalgesia (p < 0.0001) and hind paw inflammation (p < 0.034) was significantly decreased with parallel increase in the body weight of the NBD-treated (25 mg/kg) group compared to arthritic control rats. The antioxidant activity analysis demonstrated that the treatment of NBD significantly suppressed the levels of nitric oxide (p < 0.001) and peroxide (p < 0.002) with a significant increase in the glutathione (p < 0.021) compared to the arthritic control group. Since the IL-1β and TNF-α are key pro-inflammatory cytokines in arthritis, we therefore measured their levels in the serum samples. In comparison to the arthritic control group, the NBD treatment significantly reduced the levels of IL-1β (p < 0.003) and TNF-α (p < 0.026).

CONCLUSION

Our results suggests that NBD is an anti-arthritic agent that not only reduces the severity of the disease process but also affects contributing factors of arthritic inflammation including free radicals and inflammatory cytokines production.

Intraarticular gene delivery of CTLA4-FasL suppresses experimental arthritis

T lymphocytes are key inflammatory cells contributing significantly to the pathogenesis of Rheumatoid arthritis (RA). Biological treatments targeting T lymphocytes may provide an efficient approach for treatment of RA. CTLA4-FasL, a fusion product of extracellular domains of CTLA4 and FasL, integrating two inhibitory elements against T cells into one molecule, might be a desirable derivative of engineered soluble FasL or CTLA4 and have therapeutic potential in RA. The aim of this study was to investigate whether simultaneous induction of Fas-mediated apoptosis and blockade of co-stimulation signal by CTLA4-FasL gene delivery has a suppressive effect on adjuvant-induced arthritis (AIA) in Lewis rats. Recombinant adeno-associated virus (rAAV) vectors encoding rat CTLA4-FasL fusion gene (rAAV.CTLA4-FasL) or enhanced green fluorescent protein (rAAV.EGFP) were injected intraarticularly into both ankle joints after immunization. The ankles were monitored by measures of clinical, histological and inflammatory cytokines' changes. Treatment using rAAV.CTLA4-FasL resulted in a significant suppression of AIA compared with rAAV.EGFP control, as reflected in the mainly clinical signs including articular index, ankle joint thickness and paw swelling and typically histological characters of arthritic joints including synovial hyperplasia, inflammatory cells infiltration and cartilage degradation. Treatment with rAAV.CTLA4-FasL also significantly decreased the levels of key proinflammatory cytokines in AIA joints. Moreover, local productions of transgene mRNA and protein of CTLA4-FasL were found in injected joints without systemic distribution. Our results indicate that rAAV.CTLA4-FasL profoundly suppressed experimental model of RA, implicating the potential therapeutic applications for suppression of RA by local joint delivery of CTLA4-FasL.

Paeoniflorin inhibits function of synoviocytes pretreated by rIL-1α and regulates EP4 receptor expression

ETHNOPHARMACOLOGICAL RELEVANCE

To investigate the effect of the Paeoniflorin (Pae), a main active component of total glucosides of paeony (TGP) extracted from the root of Paeonia lactiflora, on regulation of synoviocytes cultured from rats collagen-induced arthritis (CIA) in vitro.

MATERIALS AND METHODS

CIA was induced in male Sprague-Dawley rats immunized with chicken type II collagen (CCII) in Freund's complete adjuvant. The levels of interleukin-1 (IL-1), tumor necrosis factor α (TNF-α), prostaglandin E(2) (PGE(2)) and cyclic adenosine monophosphate (cAMP) were measured by radioimmunoassay. The proliferation responses was determined by the 3-(4,5-2dimethylthiazal-2yl) 2,5-diphenyltetrazoliumbromide (MTT) assay. Expression of E-prostanoid (EP(4)) receptor was detected by Western blotting technique.

RESULTS

Treatment of Pae (2.5, 12.5, 62.5 μg/ml) significantly decreased the production of IL-1 and TNF-α. Recombinant interleukin-1 (rIL-1α) (10 ng/ml) apparently stimulated synoviocyte, thymocyte and splenocyte proliferation, and Pae (12.5, 62.5 μg/ml) inhibited abnormal proliferation responses stimulated by rIL-1α. Moreover, rIL-1α time- and concentration-dependently increased production of PGE(2). The production of PGE(2) produced by synoviocytes from CIA rats significantly inhibited by administration of Pae (12.5, 62.5 μg/ml). rIL-1α (10 ng/ml) decreased cAMP of synoviocytes cells treated for 24h. Similarly rIL-1α (0.1, 1, 10 ng/ml) induced a concentration-dependent decrease in the production of cAMP at 24h. Pae (12.5, 62.5 μg/ml) increased the production of cAMP in synoviocytes. The immunoblot, Pae (12.5, 62.5 μg/ml) apparently increased the expression of EP(4) receptor in synoviocytes stimulated by rIL-1α (10 ng/ml).

CONCLUSIONS

The present study indicates that Pae might exert its anti-inflammatory effects through suppressing synoviocytes function and regulating immune cells responses in CIA rats, which might be associated with its ability to up-regulate the E-prostanoid (EP(4)) receptor protein expression and modulate intracellular cAMP level.

JNK1, but not JNK2, is required in two mechanistically distinct models of inflammatory arthritis

The roles of the c-Jun N-terminal kinases (JNKs) in inflammatory arthritis have been investigated; however, the roles of each isotype (ie, JNK1 and JNK2) in rheumatoid arthritis and conclusions about whether inhibition of one or both is necessary for amelioration of disease are unclear. By using JNK1- or JNK2-deficient mice in the collagen-induced arthritis and the KRN T-cell receptor transgenic mouse on C57BL/6 nonobese diabetic (K/BxN) serum transfer arthritis models, we demonstrate that JNK1 deficiency results in protection from arthritis, as judged by clinical score and histological evaluation in both models of inflammatory arthritis. In contrast, abrogation of JNK2 exacerbates disease. In collagen-induced arthritis, the distinct roles of the JNK isotypes can, at least in part, be explained by altered regulation of CD86 expression in JNK1- or JNK2-deficient macrophages in response to microbial products, thereby affecting T-cell-mediated immunity. The protection from K/BxN serum-induced arthritis in Jnk1(-/-) mice can also be explained by inept macrophage function because adoptive transfer of wild-type macrophages to Jnk1(-/-) mice restored disease susceptibility. Thus, our results provide a possible explanation for the modest therapeutic effects of broad JNK inhibitors and suggest that future therapies should selectively target the JNK1 isoform.

Immunomodulatory activity of a Chinese herbal drug Yi Shen Juan Bi in adjuvant arthritis

OBJECTIVE

To investigate the immunomodulating mechanisms of a Chinese herbal medicine Yi Shen Juan Bi (YJB) in treatment of adjuvant arthritis (AA) in rats.

MATERIALS AND METHODS

Levels of serum tumor necrosis factor alpha (TNF-alpha) and interleukin-1beta (IL-1beta) were measured by the Enzyme-Linked Immunosorbent Assay (ELISA). Expression of TNF-alpha mRNA and IL-1beta mRNA in synovial cells was measured with the semi-quantitative technique of reverse transcription-polymerase chain reaction (RT-PCR), while caspase-3 was examined by western blot analysis.

RESULTS

The administration of YJB significantly decreased the production of serum TNF-alpha and IL-1beta. It also decreased significantly the TNF-alpha mRNA, IL-1beta mRNA, and caspase-3 expression in synoviocytes.

CONCLUSIONS

YJB produces the immunomodulatory effects by downregulating the over-activated cytokines, while it activates caspase-3, which is the key executioner of apoptosis in the immune system. This may be the one of the underlying mechanisms that explains how YJB treats the rheumatoid arthritis.

CDK-mediated regulation of cell functions via c-Jun phosphorylation and AP-1 activation

Cyclin-dependent kinases (CDKs) and their targets have been primarily associated with regulation of cell-cycle progression. Here we identify c-Jun, a transcription factor involved in the regulation of a broad spectrum of cellular functions, as a newly recognized CDK substrate. Using immune cells from mouse and human, and several complementary in vitro and in vivo approaches including dominant negative protein expression, pharmacologic inhibitors, kinase assays and CDK4 deficient cells, we demonstrate the ability of CDK4 to phosphorylate c-Jun. Additionally, the activity of AP-1, a ubiquitous transcription factor containing phosphorylated c-Jun as a subunit, was inhibited by abrogating CDK4. Surprisingly, the regulation of c-Jun phosphorylation by CDK4 occurred in non-dividing cells, indicating that this pathway is utilized for cell functions that are independent of proliferation. Our studies identify a new substrate for CDK4 and suggest a mechanism by which CDKs can regulate multiple cellular activation functions, not all of which are directly associated with cell cycle progression. These findings point to additional roles of CDKs in cell signaling and reveal potential implications for therapeutic manipulations of this kinase pathway.

Intra-articular electrotransfer of mouse soluble tumour necrosis factor receptor in a murine model of rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes inflammation and destruction of the joints. In the collagen-induced arthritis mouse model of RA, we developed a nonviral gene therapy method designed to block in situ the main cytokine tumour necrosis factor (TNF)-alpha

METHODS

Electrotransfer was used to deliver a plasmid encoding extracellular domain of mouse soluble TNF-alpha receptor type I fused to the Fc fragment of mouse immunoglobulin (Ig)G1 (pTNFR-Is) corresponding to a dimeric TNF-alpha soluble receptor fusion protein (mTNFR-Is/Ig).

RESULTS

Delivery of the plasmid into the knees at symptom onset improved the histological inflammation and destruction not only at the knees, but also at the ankles, indicating a local and a regional therapeutic effect. The plasmid was detected in synovial membrane and meniscus specimens from the injected joints. In the synovial membrane, 15 days post-injection, interleukin (IL)-17 and TNF-alpha mRNAs expression were increased, whereas IL-10 mRNA was unchanged. However, the empty plasmid exerted a pro-inflammatory effect 30 days post-injection.

CONCLUSIONS

These data indicate that local nonviral gene therapy against TNF-alpha is effective, although further work is needed to decrease plasmid induced inflammation.

IL-1 beta, IL-6, KC and MCP-1 are elevated in synovial fluid from haemophilic mice with experimentally induced haemarthrosis

The hallmark of haemophilia is the joint morbidity resulting from haemarthrosis that accounts for the majority of the bleeds. The exact mechanisms underlying changes are not fully elucidated. Cytokines are speculated to be involved in the progression and in vitro studies have confirmed the presence of elevated levels of cytokines in synovial tissue and cartilage from patients with haemophilic synovitis. In this study, the presence of selected cytokines in synovial fluid from haemophilia A mice with experimentally induced haemarthroses treated with rFVIII, rFVIIa and an rFVIIa analogue were investigated. Ten cytokines previously shown to be involved in arthritic syndromes were evaluated. Interleukin (IL)-1 beta, IL-2, IL-4, IL-6, IL-10, IL-17, Tumor Necrosis Factor-alpha (TNF- alpha), keratinocyte-derived chemokine (KC), Regulated upon Activation, Normal T cell Expressed and Secreted (RANTES) and monocyte chemotactic protein-1 (MCP-1) were included. In this article, we demonstrate, for the first time, that bleeding in knee joints of haemophilia A mice resulted in correlated increased levels of the pro-inflammatory cytokines: IL-1 beta, IL-6, KC and the MCP-1 in synovial fluid. These results suggest an important role of MCP-1 in the recruitment of monocytes and furthermore that the inflamed synovium releases IL-1 beta, IL-6 and KC, which in turn might contribute to further progression of the inflammatory process.

Kitasato symposium 2009: new prospects for cytokine inhibition

The Kitasato Symposium 2009: New Prospects for Cytokine Inhibition was held in Berlin, Germany from 7 to 9 May 2009. The key aims of this meeting were to bring together a group of front-line researchers and rheumatologists to evaluate the use of cytokine blockade and to examine the role of certain cytokines in the pathogenesis of rheumatoid arthritis and other autoimmune diseases. A keynote lecture delivered by Professor Jean-Michel Dayer provided an up-to-date overview of the interactions occurring between the immune system and acute phase proteins. Other speakers discussed the role of cytokines in rheumatoid arthritis, including their role in joint destruction, as well as their regulatory role upon T cells and B cells. The involvement of cytokines in other autoimmune diseases was also addressed.

Interleukin‐1β influences the effect of infliximab on temporomandibular joint pain in rheumatoid arthritis

OBJECTIVES

The aim of this study was to investigate the influence of plasma and synovial fluid tumour necrosis factor alpha (TNFalpha), interleukin-1beta (IL-1beta), IL-6, soluble TNF receptor II (TNF-sRII), IL-1 receptor antagonist (IL-1ra), soluble IL-1 receptor II (IL-1sRII) and IL-10 on the effect of the TNFalpha antibody infliximab on temporomandibular joint (TMJ) pain in patients with active rheumatoid arthritis (RA).

METHODS

Fifteen patients with TMJ pain taking methotrexate were included in the study. The effect of intravenous infusions of infliximab was assessed after 14 or 22 weeks. TMJ resting and movement pain was assessed by a visual analogue scale (VAS) (0-100 mm) and samples of venous blood and TMJ synovial fluid were collected before and after treatment.

RESULTS

The effect of infliximab on TMJ pain was influenced by pretreatment plasma levels of IL-1beta, IL-1ra, and IL-10 as well as pretreatment levels of TMJ synovial fluid IL-1sRII. High pretreatment levels of these cytokines and receptors as well as the presence of rheumatoid factor (RF) were associated with no or minor reduction in TMJ pain after treatment.

CONCLUSIONS

Systemic treatment of RA with a combination of infliximab and methotrexate seems to be insufficient to alleviate TMJ pain in patients with RF or high pretreatment plasma levels of IL-1beta.

Effects and mechanisms of total glucosides of paeony on synoviocytes activities in rat collagen-induced arthritis

The aim of the study was to investigate the effects of TGP, an active compound extracted from the roots of Paeonia lactiflora Pall, on the activities of synoviocytes in rats with collagen-induced arthritis (CIA) and its possible mechanisms. CIA was induced in male Sprague-Dawley (SD) rats immunized with chicken type II collagen (CII) in Freund's complete adjuvant (FCA). Synoviocytes proliferation was determined by 3-(4, 5-2dimethylthiazal-2yl) 2, 5-diphenyltetrazoliumbromide (MTT) assay. Tumor necrosis factor alpha (TNF-alpha), interleukin-1 (IL-1), prostaglandin E(2) (PGE(2)) and cyclic adenosine monophosphate (cAMP) levels in synoviocytes were measured by radioimmunoassay (RIA). E-prostanoid (EP)(2) and EP(4) receptors were analyzed by Western blot analysis. The results showed that TGP significantly inhibited the proliferation of synoviocytes, decreased the production of IL-1, TNF-alpha and PGE(2) and elevated the levels of cAMP. Further study showed that TGP could up-regulate the expression of EP(2) and EP(4). These results indicated that TGP might exert its anti-inflammatory effects through inhibiting the production of pro-inflammatory mediators in synoviocytes of CIA rats, which might be associated with its ability to regulate cAMP-dependent EP(2)/EP(4)-mediated pathway.

HLA-B27 and host-pathogen interaction

HLA-B27 is a risk factor closely associated to spondyloarthropathies (SpA). One form of SpA is reactive arthritis (ReA), which develops as a complication after certain bacterial infections (e.g., Salmonellae, Yersiniae, Shigellae, Campylobacteriae and Chlamydiae). The development of infection-triggered complication is a complex train of events between the triggering bacteria and the host. Since most of the patients suffering from ReA are HLA-B27 positive, it has been proposed that HLA-B27 may modulate the interaction between ReA-triggering bacteria and host cell. Besides antigen presenting function, HLA-B27 displays other unusual properties that might be of importance in the development of ReA. These properties (homodimer formation and misfolding of HLA-B27 heavy chain in the endoplasmic reticulum (ER)) may trigger ER-stress signaling pathways in host cell, which in turn may modulate cell signaling in favor of ReA-triggering bacteria. Here we summarize the observations of HLA-B27 modulating the interaction between ReA-triggering bacteria and host cell and discuss potential mechanisms behind the interaction.

Inhibition of the lipopolysaccharide-induced stimulation of the members of the MAPK family in human monocytes/macrophages by 4-hydroxynonenal, a product of oxidized omega-6 fatty acids

The compound 4-hydroxynonenal (4-HNE) is the major aldehyde formed during lipid peroxidation of omega-6-polyunsaturated fatty acids and has been suggested to regulate inflammatory responses because it inhibits tumor necrosis factor (TNF) mRNA production in the human monocytic cell line THP-1. Here we demonstrate that 4-HNE inhibits TNF and interleukin-1beta production in human monocytes in response to lipopolysaccharide. The main action of 4-HNE occurred at the pretranscriptional level; there was no effect on TNF mRNA production or stability when 4-HNE was added after stimulation. The mechanism of action of 4-HNE appears to be downstream of lipopolysaccharide-receptor binding. In the human monocytic MonoMac 6 cell line, 4-HNE caused selective inhibition of the activity of the mitogen-activated protein kinases p38 and ERK1/ERK2, but not JNK. However, in monocytes, the activities of all three kinases were inhibited, suggesting that the effects of 4-HNE were exerted at points upstream of ERK1/ERK2 and JNK as the levels of the phosphorylated kinases were reduced. In contrast, p38 phosphorylation was not inhibited, suggesting that 4-HNE affects kinase activity. 4-HNE also inhibited nuclear factor-kappaB activation in monocytes. In view of the roles of p38, ERK1/ERK2, JNK, and nuclear factor-kappaB in inflammation, the data suggest that 4-HNE, at nontoxic concentrations, has anti-inflammatory properties, most likely through an effect on these signaling molecules, and could lead to the development of novel treatments for inflammatory diseases.

MAPK phosphatases as novel targets for rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) represents a challenge for therapeutic interventions due to complex inflammatory signalling pathways underlying its pathogenesis. The MAPK signalling network, a major effector limb of the inflammatory lesion, is an attractive therapeutic target. MAPK phosphatases (MKPs), endogenous negative regulators of MAPK signalling, have received increasing recognition as modulators of inflammatory and immune responses, and hence as a potential therapeutic avenue for RA.

OBJECTIVE

To present the rationale for therapeutically targeting MAPK signalling and explore the case for addressing MKP1 as a novel therapeutic strategy for RA.

METHODS

We summarise literature describing the importance of MAPK signalling in RA and review reports describing the roles of MKPs in modulating innate and adaptive immune responses. Finally we expand on the role of MKP1 in RA pathogenesis and explore data defining MKP1 as a mediator of glucocorticoid action.

CONCLUSION

MKP1 constitutes an exciting, novel potential therapeutic target for RA.

Treatment with N-tosyl-l-phenylalanine chloromethyl ketone after the onset of collagen-induced arthritis reduces joint erosion and NF-kappaB activation

N-tosyl-l-phenylalanine chloromethyl ketone (TPCK) is known to inhibit NF-kappaB activation and the expression of inflammation mediators in cultured cells. We measured the potential of TPCK to inhibit the pathogenesis of collagen-induced arthritis by blocking NF-kappaB activation. Arthritis was induced in DBA/1J mice by the injection of bovine type II collagen in adjuvant on days 0 and 14. Mice received either TPCK (3 or 10 mg/kg, i.p.) or vehicle three times a week for 3 weeks starting on day 21. TPCK moderately reduced clinical disease activity scores, whereas it markedly suppressed histological indications of joint destruction. In vitro production of tumor necrosis factor-alpha, interleukin-6, and monocyte chemotactic protein-1 from lipopolysaccharide-stimulated spleen cells was also reduced by in vivo treatment with TPCK. Proliferation of cells isolated from spleen or draining lymph nodes and production of interferon-gamma and interleukin-17 in response to stimulation with type II collagen was decreased by TPCK. Moreover, nuclear NF-kappaB activity induced by collagen immunization was significantly reduced in mice treated with TPCK. Finally, osteoclast differentiation of bone marrow cells induced by macrophage colony-stimulating factor and receptor activator of NF-kappaB ligand was completely inhibited by TPCK. These results indicate that TPCK attenuates collagen-induced arthritis and bone erosion by suppressing NF-kappaB activation and thus expression of inflammatory and osteoclastogenic genes.

Suppressive role of leukocyte cell-derived chemotaxin 2 in mouse anti-type II collagen antibody-induced arthritis

OBJECTIVE

We previously reported that the Val58Ile polymorphism of the leukocyte cell-derived chemotaxin 2 gene (LECT2) is associated with the severity of rheumatoid arthritis (RA). To define the role of LECT2 in inflammatory arthritides, we investigated the development of collagen antibody-induced arthritis (CAIA) in LECT2-deficient (LECT2(-/-)) mice.

METHODS

CAIA was induced in mice by administering anti-type II collagen antibodies followed by lipopolysaccharide. Daily assessment of hind paw swelling was used to monitor the development of arthritis. The histopathologic features and expression of inflammatory cytokines were also analyzed. We confirmed the role of LECT2 by introducing a LECT2 expression vector into LECT2(-/-) mice, using a hydrodynamic gene transfer method.

RESULTS

Arthritis in LECT2(-/-) mice was significantly exacerbated compared with that in wild-type (WT) controls. Histopathologic assessment of the tarsal joints showed that inflammation and erosion of cartilage and bone in LECT2(-/-) mice were more severe than that in controls. Interleukin-1beta (IL-1beta), IL-6, and certain chemokines were present at significantly higher levels in the arthritic hind paws of LECT2(-/-) mice. In contrast, the amount of LECT2 in the serum and locally in the hind paws was higher in arthritic WT mice. Finally, hydrodynamic gene transfer experiments revealed that the severity of arthritis was reduced by the systemic expression of exogenous mouse LECT2 protein in LECT2(-/-) mice.

CONCLUSION

These results strongly suggest that LECT2 directly suppresses the development of CAIA. Manipulation of LECT2 might provide a rationale for novel therapeutic approaches to the treatment of inflammatory arthritides such as RA.

Co-expression of IL-18 binding protein and IL-4 regulates Th1/Th2 cytokine response in murine collagen-induced arthritis

We constructed a recombinant adenoviral vector containing a murine interleukin (IL)-18 binding protein (mIL-18BP) and murine IL-4 (mIL-4) fusion gene (AdmIL-18BP/mIL-4) and used a gene therapy approach to investigate the role of IL-18BP and IL-4 in modulating the T-helper1 and T-helper2 (Th1/Th2) balance in mice with collagen-induced arthritis (CIA). Mice with CIA were intra-articularly injected with 107 pfu/6 microl of either AdmIL-18BP/mIL-4, or a control adenovirus, or with the control vehicle (phosphate-buffered saline). After intra-articular gene therapy with AdmIL-18BP/mIL-4, the serum levels of tumor necrosis factor-alpha (TNF-alpha), gamma-interferon (IFN-gamma), IL-4, IL-10, and IL-18 in mice with CIA were assessed by ELISA. IFN-gamma-expressing and IL-4-expressing CD4+ T cells from mice splenocytes were monitored by flow cytometry. Mice with CIA at weeks 1, 2, and 4 after intra-articular injection of AdmIL-18BP/mIL-4 showed significantly increased serum concentrations of IL-4 and IL-10 (P<0.01 at all time points) but greatly decreased serum concentrations of IFN-gamma, TNF-alpha, and IL-18 (P<0.01 at all time points) compared to both the control adenovirus and phosphate-buffered saline control groups. The percentage of IFN-gamma-producing CD4+ T cells was significantly decreased in response to local AdmIL-18BP/mIL-4 treatment. The percentage of IL-4-producing CD4+ T cells increased significantly at 1 week after local injection of AdmIL-18BP/mIL-4 then returned to normal by week 4. These data indicated the significant modifying effects on the Th1/Th2 imbalance in murine CIA produced by local overexpression of IL-18BP and IL-4. Combination treatment with IL-18BP and IL-4 is a promising potential therapy for rheumatoid arthritis.

Effects and mechanisms of total glucosides of paeony on adjuvant arthritis in rats

Total glucosides of paeony (TGP) is the major active constituent of Paeonia lactiflora Pall. The present study was carried out to investigate the effects of TGP on adjuvant arthritis (AA) of rat and its possible mechanisms. AA was induced by metatarsal footpad injection with complete Freund's adjuvant in male Sprague-Dawley rats. The secondary inflammatory reaction was evaluated by hind paw swelling, polyarthritis index. Activity of interleukin-1 (IL-1) was detected by Con A-induced thymocytes proliferation of C57BL/6J mice assay. The tumor necrosis factor alpha (TNFalpha), prostaglandin E(2) (PGE(2)) and cyclic adenosine monophosphate (cAMP) levels in synoviocytes were assessed by radioimmunoassay (RIA). PGE(2) receptors, EP2 and EP4, were analyzed by Western blot analysis. The level of IL-6 was measured by ELISA. Intragastric administration of TGP (50,100 mg/kg) significantly decreased secondary inflammatory reaction in AA rats. Suppressing the activity of IL-1 and TNFalpha, decreased PGE(2) and increased cAMP levels in synoviocytes of AA rats were observed after administration of TGP. In the immunoblot analysis, TGP could up-regulate the expression of EP2 and EP4. These results showed TGP significantly inhibited the progression of AA, and the inhibitory effects might be associated with its ability to mediate the level of cAMP and inhibit the production of IL-1, TNFalpha, IL-6 and PGE(2) from activated synoviocytes.

Cytokine profile in synovial fluid from patients with internal derangement of the temporomandibular joint: a preliminary study

OBJECTIVES

Temporomandibular joint disorders (TMD) comprise a group of chronic painful conditions of mastication in the temporomandibular joint (TMJ). Although the association between TMD and internal derangement of the TMJ is well documented, the functional relevance is still unclear. Increased concentrations of inflammatory mediators have been identified in the synovial fluid of affected patients with TMD, suggesting an underlying degenerative or inflammatory process. The aim of this study was to generate a comprehensive cytokine expression profile in TMD.

METHODS

15 samples from patients with internal derangement of TMJ were analysed using a novel cytokine array that enables the analysis of 79 different cytokines simultaneously.

RESULTS

Cytokine levels were correlated with the presence of joint effusion (JE) determined by MRI. In the majority of synovial fluid samples, angiogenin (Ang), fibroblast growth factor (FGF)-9, insulin-like growth factor-binding protein (IGFBP)-3, interleukin (IL)-1alpha, IL-1beta, IL-8, inducible protein (IP)-10, macrophage inflammatory protein (MIP)-1beta, osteoprotegerin (OPG), transforming growth factor (TGF)-beta2, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2, tumour necrosis factor (TNF)-beta and vascular endothelial growth factor (VEGF) were detectable. Furthermore, the expression levels of Ang, brain-derived neurotrophic factor (BDNF), FGF-4, FGF-9, IGFBP-2, IL-8, MIP-1beta, OPG, pulmonary and activation-regulated protein (PARC), TGF-beta2, TIMP-2 and VEGF were significantly associated with the presence of JE; among these, nine cytokines (Ang, BDNF, FGF-4, FGF-9, IGFBP-2, MIP-1beta, PARC, TGF-beta2 and TIMP-2) were hitherto not described in TMD.

CONCLUSIONS

This study confirmed previous reports of elevated cytokine levels in TMD. Additionally, we identified previously undescribed cytokines that were upregulated and correlated significantly with the presence of JE. We were able to identify novel cytokines that have hitherto not been described in TMD. Strategies targeting the identified cytokines may represent a novel therapy option in TMD.

THR0921, a novel peroxisome proliferator-activated receptor gamma agonist, reduces the severity of collagen-induced arthritis

THR0921 is a novel peroxisome proliferator-activated receptor gamma (PPARγ) agonist with potent anti-diabetic properties. Because of the proposed role of PPARγ in inflammation, we investigated the potential of orally active THR0921 to inhibit the pathogenesis of collagen-induced arthritis (CIA). CIA was induced in DBA/1J mice by the injection of bovine type II collagen in complete Freund's adjuvant on days 0 and 21. Mice were treated with THR0921 (50 mg/kg/day) starting on the day of the booster injection and throughout the remaining study period. Both clinical disease activity scores as well as histological scores of joint destruction were significantly reduced in mice treated with THR0921 compared to untreated mice. Proliferation of isolated spleen cells, as well as circulating levels of IgG antibody to type II collagen, was decreased by THR0921. Moreover, spleen cell production of IFN-γ, tumor necrosis factor (TNF)-α and IL-1β in response to exposure to lipopolysaccharide or type II collagen was reduced by in vivo treatment with THR0921. Steady state mRNA levels of TNF-α, IL-1β, monocyte chemotactic protein-1 and receptor activator of nuclear factor κB ligand (RANKL) in isolated joints were all decreased in mice treated with THR0921. Finally, THR0921 inhibited osteoclast differentiation of bone marrow-derived cells stimulated with macrophage colony-stimulating factor and RANKL. In conclusion, THR0921 attenuates collagen-induced arthritis in part by reducing the immune response. As such, PPARγ may be an important therapeutic target for rheumatoid arthritis.