Tumor necrosis factor-alpha blockade: a novel therapy for rheumatic disease

Thymoquinone Inhibition of Chemokines in TNF-α-Induced Inflammatory and Metastatic Effects in Triple-Negative Breast Cancer Cells

The lack of identifiable molecular targets or biomarkers hinders the development of treatment options in triple-negative breast cancer (TNBC). However, natural products offer a promising alternative by targeting inflammatory chemokines in the tumor microenvironment (TME). Chemokines are crucial in promoting breast cancer growth and metastasis and correlate to the altered inflammatory process. In the present study, we evaluated the anti-inflammatory and antimetastatic effects of the natural product thymoquinone (TQ) on TNF-α-stimulated TNBC cells (MDA-MB-231 and MDA-MB-468) to study the cytotoxic, antiproliferative, anticolony, antimigratory, and antichemokine effects using enzyme-linked immunosorbent assays, quantitative real-time reverse transcription-polymerase chain reactions, and Western blots were used in sequence to validate the microarray results further. Four downregulated inflammatory cytokines were identified, CCL2 and CCL20 in MDA-MB-468 cells and CCL3 and CCL4 in MDA-MB-231 cells. Furthermore, when TNF-α-stimulated MDA-MB-231 cells were compared with MDA-MB-468 cells, the two cells were sensitive to TQ's antichemokine and antimetastatic effect in preventing cell migration. It was concluded from this investigation that genetically different cell lines may respond to TQ differently, as TQ targets CCL3 and CCL4 in MDA-MB-231 cells and CCL2 and CCL20 in MDA-MB-468 cells. Therefore, the results indicate that TQ may be recommended as a component of the therapeutic strategy for TNBC treatment. These outcomes stem from the compound's capacity to suppress the chemokine. Even though these findings support the usage of TQ as part of a therapy strategy for TNBC associated with the identified chemokine dysregulations, additional in vivo studies are needed to confirm these in vitro results.

The Effect of Chia Seed Extracts against Complete Freund’s Adjuvant-Induced Rheumatoid Arthritis in Rats

Background and Objectives. It is known that the oxidation of chia seeds is minimal or absent, due to the presence of bioactive compounds, having a great potential in the foods and pharmacological industry. This investigation was done to estimate the nutrition values and anti-oxidant activity of chia seed extracts. Materials and Methods. The protective effects of chia seed extract against complete Freund’s adjuvant (CFA) rheumatoid arthritis in rats were investigated with 100, 200, 300, and 400 ppm/kg BW rat/day chia seeds aqueous extract for 4 weeks. Results. The results obtained revealed that chia seed extract contained high proportions of protein and total dietary fiber values of 21.35% and 27.24%, respectively. Moreover, the results reported that the mineral contents were the greatest in phosphorous, potassium, magnesium, calcium, and sodium (450.09, 410.46, 245.22, 218.69, and 120.34 mg/100 g, respectively). Meanwhile, iron, zinc, and copper were the lowest in chia seeds (9.26, 4.67, and 3.66 mg/100 g, respectively). Besides, vitamins C and E reported 1.65 and 0.82 mg/100 g, respectively. Chia seed extracts were effective in vitro for the bioactive components such as phenolics, flavonoids, and anti-oxidant activities. The biomarkers of complete blood picture, lipid profile, anti-oxidant enzymes, TNF-α, and IL-10 had been improved. Histopathological examination of the rat knee confirmed health amelioration, revealing that chia seed extract consumption can lower pathological changes in injured rheumatoid arthritis rats. Conclusion. It could be seen that the chia seed extracts alleviated the harmful effect of rheumatoid arthritis CFA-induced rats.

ADAMTS-4 as a possible distinguishing indicator between osteoarthritis and haemophilic arthropathy

Introduction

Osteoarthritis (OA) and haemophilic arthropathy (HA) are clinically similar, but pathologically distinct conditions which result in joint pain and loss of function. Distinguishing their disease mechanisms is therefore a key step in the development of curative therapy, as opposed to current symptomatic treatments. A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 4 is a metzincin‐family member proteoglycan with known local involvement in OA pathogenesis.

Aim

To investigate the potential differences and discriminatory potential of ADAMTS‐4 between OA and HA patients.

Methods

We determined ADAMTS‐4 plasma concentrations by ELISA in patients with HA and OA. This pilot cross‐sectional study included N = 40 male participants equally divided across four subgroups: haemophilia patients with severe or mild HA and control subjects with severe or mild/no OA.

Results

Our study showed a striking elevation in plasma ADAMTS‐4 expression levels in HA patients as compared to OA, as well as an increase in patients with severe as compared to mild HA. By performing the binomial logistical analysis and fitting the receiver–operator curve (ROC) (cut‐off probability .5), ADAMTS‐4 had a sensitivity of 95% and specificity of 50% in discriminating between HA and OA among our study participants.

Conclusion

Uncovering the marked differences in plasma levels of ADAMTS‐4 in patients with HA versus OA potentially sheds new light on the mechanisms of HA pathogenesis and could foster more research into the roles ADAMTS‐4 and other matrix metalloproteinases (MMPs) play in HA versus OA.

Gastrointestinal absorption, antiproliferative and anti-inflammatory effect of the major carotenoids of Gardenia jasminoides Ellis on cancer cells

Crocetin was the carotenoid with the highest gastrointestinal transport efficiency and the most effective in inhibiting cancer cell proliferation. In addition, this carotenoid showed involvement in the downregulation of the inflammatory cytokines.

Tetrathiomolybdate Therapy Protects Against Concanavalin a and Carbon Tetrachloride Hepatic Damage in Mice

Tetrathiomolybdate, an anticopper drug, has been shown to protect mice against pulmonary fibrosis from bleomycin. Our hypothesis is that it does so by inhibiting fibrosis-inducing cytokines. Indeed, we have good evidence, not yet published, that tetrathiomolybdate inhibits pulmonary levels of transforming growth factor–β and tumor necrosis factor-α expression in these bleomycin experiments. Herein, we evaluate tetrathiomolybdate's effectiveness in mitigating hepatitis and fibrosis in mice from the hepatotoxins, concanavalin A and carbon tetrachloride, and its inhibition of cytokines as a possible mechanism. In short-term experiments, concanavalin A elevated serum amino leucine transferase levels several fold, and tetrathiomolybdate completely prevented this increase. In additional experiments, tetrathiomolybdate therapy reversed the elevated serum transaminase levels despite continued concanavalin A injections, with nearly significant serum interleukin-1β inhibition. Concanavalin A given for 12 weeks produced mild fibrosis, whereas concomitant tetrathiomolybdate treatment resulted in normal histology. Carbon tetrachloride given for 12 weeks resulted in very high serum amino leucine transferase levels, high serum transforming growth factor–β levels, cirrhosis as seen histologically, and increase in liver hydroxyproline, a measure of fibrosis. Concomitant tetrathiomolybdate partially and significantly protected against increases in amino leucine transferase and transforming growth factor–β, fully protected against the increase in hydroxyproline, and resulted in normal histology. In conclusion, tetrathiomolybdate protects against the hepatitis and fibrosis produced by these hepatotoxins, probably by inhibiting the excessive increase in inflammatory and fibrotic cytokines.

Endogenous cannabinoid anandamide impairs cell growth and induces apoptosis in chondrocytes

Endocannabinoids has been described to be involved in articular degenerative disease by modulating nociception and immune system. However, the role of the endocannabinoid anandamide on chondrocyte cell viability is still unclear. Therefore, we decided to study anandamide's effects on chondrocytes viability and to evaluate its interactions with the catabolic factor TNF (tumor necrosis factor). Chondrocyte vitality was evaluated by MTT assay. We investigated LDH release, chromatin condensation, cleavage of focal adhesion kinase (FAK), and caspases-3, 8, and 9 activation. c-MYC mRNA levels were determined by RT-PCR. We studied by Western blot the activation patterns of AKT, AMPK, ERK, p38, and JNK kinases. Finally, we evaluate the effect of anandamide in TNF-induced caspase-3 cleavage. Anandamide decreased chondrocyte vitality independently of its receptors. It induced AMPK activation without LDH release. Anandamide induced chromatin condensation, activation of caspase-3, 8, and 9, and FAK cleavage. Surprisingly, despite anandamide inhibited cell proliferation, it increased c-MYC expression. Moreover anandamide inhibited AKT activation, whilst it induced a sustained activation of ERK, JNK, and p38. Finally, anandamide synergized with TNF-α in the cleavage of caspase-3. In conclusion, our findings suggest that anandamide, alone or in combination with TNF-α, may be a potential destructive agent in cartilage.

The predictive value of somatic and cognitive depressive symptoms for cytokine changes in patients with major depression

CONTEXT

Elevated concentrations of proinflammatory cytokines have been hypothesized as an important factor in the pathophysiology of depression. Depression itself is considered to be a heterogeneous disorder. Current findings suggest that "cognitive" and "somatic" symptom dimensions are related to immune function in different ways. So far, little research has been done on the longitudinal aspects of inflammation in patients with major depression, especially with respect to different symptom dimensions of depression. Therefore, we investigated which aspects of depression may predict changes in tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6 over 4 weeks.

METHODS

Forty-one patients with major depression diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), and 45 healthy controls were enrolled. Serum measurements of TNF-alpha and IL-6 were conducted at baseline and 4 weeks later. Psychometric measures included the assessment of cognitive-affective depressive symptoms and somatic symptoms during the last 7 days as well as somatic symptoms during the last 2 years.

RESULTS

Patients with depression showed increased levels of TNF-alpha (P<0.05) compared to healthy controls. Hierarchical regression analyses indicated that neither depressive nor somatic symptoms predict changes in proinflammatory cytokines in the whole sample of depressed patients. Moderation analyses and subsequent sex-stratified regression analyses indicated that higher somatoform symptoms during the last 2 years significantly predict an increase in TNF-alpha in women with major depression (P<0.05) but not in men. Exploratory analyses indicated that the stability of TNF-alpha and IL-6 (as indicated by intraclass correlation coefficients) over 4 weeks was high for TNF-alpha but lower for IL-6.

CONCLUSION

The present study demonstrated that a history of somatoform symptoms may be important for predicting future changes in TNF-alpha in women with major depression.

The effect of golimumab on haemoglobin levels in patients with rheumatoid arthritis, psoriatic arthritis or ankylosing spondylitis

OBJECTIVE

To evaluate the effect of golimumab on haemoglobin levels in patients with RA, PsA or AS.

METHODS

Secondary analysis was performed on integrated data from five randomized controlled studies: three RA, one PsA and one AS (2303 patients total). Golimumab 50 or 100 mg was injected s.c. every 4 weeks with or without MTX. Control groups received placebo injections plus MTX or background therapy. Patients with haemoglobin levels below the age- and sex-specific normal ranges were considered to have anaemia. Ferritin levels were used to distinguish anaemia of mixed aetiology (≥ 15 and <60 ng/ml) and anaemia of inflammation (≥ 60 ng/ml). Changes from baseline to weeks 14 and 24 in haemoglobin level were compared between treatment groups using an analysis of variance on the van der Waerden normal scores.

RESULTS

At baseline, 21% of RA patients, 9% of PsA patients and 15% of AS patients had anaemia. Of these, 24%, 57% and 25%, respectively, had anaemia of inflammation. The median increase from baseline to week 14 in the haemoglobin level of anaemic patients was 0.3 g/dl in the control group and 0.9 g/dl in the golimumab group (P < 0.001). Haemoglobin levels improved within the subgroups of patients with anaemia of mixed aetiology (control, 0.4 g/dl vs golimumab, 0.7 g/dl) (P = 0.305) and with anaemia of inflammation (0.2 vs 1.4 g/dl, respectively) (P < 0.001).

CONCLUSION

Compared with the control group, patients receiving golimumab treatment had significantly improved haemoglobin levels, particularly among patients with anaemia of inflammation.

Role of RNA-binding protein tristetraprolin in tumor necrosis factor-α mediated gene expression

Tumor necrosis factor-α (TNF-α) plays an important role in the pathogenesis of inflammatory diseases. Excessive TNF-α expression induces tristetraprolin (TTP), an RNA-binding protein that regulates mRNA degradation, which in turn downregulates TNF and its downstream genes, thus resulting in anti-inflammatory effects. In order to better understand the TNF-α mediated molecular pathways in inflammatory diseases, embryonic fibroblast (MEF) cell lines derived from TTP-deficient (KO) or wild type (WT) mice were treated with TNF-α and gene expression differences between two cell lines were compared by a microarray essay of 9224 genes. We found that TTP-KO cells had higher expression levels of pro-inflammatory genes than TTP-WT cells, and inflammatory genes were differentially regulated by TNF-α between TTP-KO and TTP-WT cells. Through a study of 2-dimentional gene set matrix analysis, we also found the genes upregulated by TNF-α in TTP KO cells were correlated with the pathologic phenotypes in inflammation, joint, or bone diseases. Our study provided a detailed genetic roadmap for further understanding the regulatory effect of TTP in inflammatory pathways related to human diseases.

Emerging ideas: can erythromycin reduce the risk of aseptic loosening?

BACKGROUND

Persistent inflammatory reaction to wear debris causes periprosthetic osteolysis and loosening. Some authors have advocated pharmaceutical approaches to reduce the inflammatory reaction. Erythromycin has antiinflammatory effects independent of its antimicrobial properties. Although oral erythromycin reportedly inhibits periprosthetic tissue inflammation in patients with aseptic loosening, long-term systematic erythromycin treatment is not recommended owing to its side effects. Therefore, it would be advantageous to restrict erythromycin delivery to the inflammatory periprosthetic tissue without causing side effects.

QUESTIONS/HYPOTHESES

Erythromycin eluted from hydroxyapatite-coated titanium (Ti) pins inhibits periprosthetic tissue inflammation and osteolysis.

METHOD OF STUDY

We propose restricting erythromycin delivery to the inflammatory periprosthetic site. A previously described rat model of ultrahigh molecular weight polyethylene (UHMWPE) particle-induced periprosthetic tissue inflammation and osteolysis will be used to test the effect of local delivery of erythromycin via Peri-Apatite(TM)-coated Ti implants. The outcome measures will include bone ingrowth (μCT), implant stability (pullout test), and histologic analysis of periprosthetic tissues.

SIGNIFICANCE

Pharmacologic intervention aimed at slowing, preventing, or reversing the aseptic loosening process would represent an advance in the management of joint replacement. Erythromycin may be appropriate for prophylactically treating patients who have repeated revision surgery and/or show early signs of progressive osteolysis after arthroplasty.

Antifibrosis effects of total glucosides of Danggui-Buxue-Tang in a rat model of bleomycin-induced pulmonary fibrosis

AIM OF THE STUDY

The present study examined the antifibrosis effects of DBTG (total glucosides of Danggui-Buxue-Tang) on bleomycin-induced pulmonary injury and fibrosis in rats.

MATERIALS AND METHODS

Animals were randomly divided into six groups: (1) saline control group; (2) Bleomycin group in which rats were endotracheally instillated with bleomycin (5mg/kg); (3-5) Bleomycin and DBTG group, in which DBTG were given to rats daily (16.32 or 64mg/kg/day, i.g.) one day after bleomycin injection for 4 weeks until the end of the treatment; (6) Bleomycin and positive control group. Animals were sacrificed at 7, 14, and 28 days post bleomycin administration and lungs were removed. Lung specimens were stained with hematoxylin and eosin (HE) and Masson trichrome for histological evaluation of lung injury and fibrosis by light microscopy. Body weight and lung index from various groups were measured, as well as TNF-α, TGF-β1 and type I collagen concentrations in lung homogenates.

RESULTS

DBTG reduced bleomycin-induced weight loss, decreased the lung index and histological evidence supported the ability of DBTG to attenuate bleomycin-induced lung fibrosis and consolidation. DBTG could partly dose-dependently decrease TNF-α and TGF-β1 activity, as well as it decrease type I collagen expression in lung tissues.

CONCLUSIONS

The findings of the present study provide evidence that DBTG may serve as a novel target for potential therapeutic treatment of lung fibrosis.

Anti-inflammatory and Anti-arthritic Effects of a Novel Leflunomide Analogue, UTL-5b (GBL-5b)

Rheumatoid arthritis (RA) is a common disease characterized by chronic inflammation and irreversible destruction of articular cartilage and bone. In this report, we examined the anti-inflammatory and anti-arthritic effects of a novel leflunomide analogue, UTL-5b (also known as GBL-5b), for potential RA treatment. Using a carrageenan-induced edema study in rats, UTL-5b exhibited a better anti-inflammatory effect as compared with leflunomide and its metabolite. The chronic efficacy of UTL-5b was examined using type II collagen-induced arthritis (CIA) mouse model. UTL-5b exerted an anti-arthritic effect in a dose-dependant manner with mice given 30 mg/kg exhibiting amelioration of disease early in the trial, but losing statistical significance over time. In contrast, mice treated with 60 mg/kg showed reduced clinical disease parameters early in the trial and these effects were sustained over the ten week trial period. Mechanistic studies indicate that UTL-5b is an inhibitor of TNF-α production in vivo. Oral administration of UTL-5b prior to i.p. injection with lethal dose of lipopolysaccharide (LPS)/D-galactosamine markedly reduced the levels of serum TNF-α and increased survival rates of animals from septic shock-induced death. Acute toxicity study using mice receiving increasing doses of UTL-5b showed that no animals were killed by UTL-5b at 2,000 mg/kg (LD(50) >2,000 mg/kg). Our studies show that UTL-5b represents a novel anti-inflammatory and anti-arthritic agent with potential therapeutic application for RA treatment.

Suppressive effects of the flavonoids quercetin and luteolin on the accumulation of lipid rafts after signal transduction via receptors

Quercetin (QUER) and luteolin (LUTE) are dietary flavonoids capable of regulating the production of cytokines, such as tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6). However, their mechanisms of action are not fully understood. In lipopolysaccharide-triggered (LPS)-triggered signaling via Toll-like receptor 4 (TLR4), QUER and LUTE suppresses not only the degradation of the inhibitor of kappaB (IkappaB), with resultant activation of nuclear factor-kappaB (NF-kappaB), but also the phosphorylation of p38 and Akt in bone marrow-derived macrophages that have been stimulated with LPS. We report here that, in TNF-alpha-induced signaling, QUER and LUTE significantly suppressed the production of IL-6 and activation of NF-kappaB. Accumulation of lipid rafts, the initial step in the signaling pathway, was significantly inhibited when macrophages were treated with QUER or with LUTE prior to exposure to LPS. Similarly, the accumulation of lipid rafts was inhibited by the flavonoids when B cells were activated via the membrane IgM and when T cells were activated via CD3. In contrast, QUER and LUTE did not inhibit the activation of phorbol myristate acetate-induced NF-kappaB in macrophages. Our observations suggest that QUER and LUTE interact with receptors on the cell surface and suppress the accumulation of lipid rafts that occurs downstream of the activation of the receptors.

Chemokines – their role in immunotherapy for intraocular inflammation

Chemotactic cytokines are responsible for leukocyte migration and the immunopathogenesis of various inflammatory lesions. Together with other types of cytokines, chemokines play a major role in inducing/regulating inflammation and various immune responses. By targeting chemokines, immunotherapies could become another option for treating patients with uveitis. Indeed, a variety of chemokine-based therapies have been tested for their possible application for various pathological diseases, including intraocular inflammation. An example of chemokine-based therapy is anti-tumor necrosis factor (TNF)-alpha therapy, a very successful treatment. Chemokine- and cytokine-based therapies, therefore, appear to be a promising choice for the treatment of intraocular inflammation.

Osteopontin is dispensable for protection against high load systemic fungal infection

Osteopontin (OPN) is a multi-functional cytokine which is involved in the pathogenesis of autoimmune disease. We previously reported that thrombin-cleaved form of OPN plays a pathogenic role in murine model of rheumatoid arthritis (RA) by using neutralizing antibody (M5) reacting against the cryptic epitope within OPN, exposed by thrombin cleavage of OPN. It has been shown that OPN-deficient mice are susceptible to various infections, demonstrating the protective role of OPN against various infectious diseases. However, it remains to be clarified whether and how OPN is involved in protection against systemic fungal infection. In a murine model of systemic fungal infection, OPN-deficient mice showed the increase in the susceptibility to low load, but not to high load fungal infection, indicating the protective of OPN against mild or severe forms of infections. However, mice treatment with M5 antibody did not alter the susceptibility to both high and low load fungal infection. These experiments suggest that in sharp contrast to the complete abrogation of OPN expression in OPN-deficient mice, the neutralization of OPN by antibody against thrombin-cleaved form of OPN does not interfere with the host defense against high and low load fungal infection. These findings suggest that the neutralizing antibody which is specific for the epitope of thrombin-cleaved OPN may become an attractive therapeutic means for the treatment of RA without interfering host defense system.

Patients with rheumatoid arthritis have an altered circulatory aggrecan profile

Background

Rheumatoid arthritis (RA) is a chronic auto-immune disease with extensive articular cartilage destruction. Aggrecan depletion, mediated by aggrecanases is one of the first signs of early cartilage erosion. We investigated, whether measurement of aggrecan and fragments thereof in serum, could be used as biomarkers for joint-disease in RA patients and furthermore characterized the fragments found in the circulation.

Methods

The study consisted of 38 patients, 12 males (62.2 ± 16.0 years) and 26 females (59.8 ± 20.7 years) diagnosed with RA: 41.5 ± 27.5 mm/h erythrocyte sedimentation rate (ESR), 38.4 ± 34.7 mg/ml C-reactive protein (CRP) and 4.8 ± 1.7 disease activity score (DAS) and 108 healthy age-matched controls. Aggrecan levels were measured using two immunoassays, i.e. the ³⁷⁴ARGSVI-G2 sandwich ELISA measuring aggrecanase-mediated aggrecan degradation and the G1/G2 sandwich assay, detecting aggrecan molecules containing G1 and/or G2 (total aggrecan) We further characterized serum samples by western blots, by using monoclonal antibodies F-78, binding to G1 and G2, or by BC-3, detecting the aggrecanase-generated N-terminal ³⁷⁴ARGSVI neo-epitope.

Results

Total aggrecan levels in RA patients were significantly decreased from 824.8 ± 31 ng/ml in healthy controls to 570.5 ± 30 ng/ml (31% decrease, P < 0.0001), as measured by the G1/G2 ELISA. Western blot analysis with F-78 showed one strong band at 10 kDa, and weaker bands at 25 and 45 kDa in both healthy controls and RA patients. In contrast, staining for aggrecanase-activity revealed only one strong band in RA patients of 45 kDa.

Conclusion

This is the first study, which characterizes different aggrecan fragments in human serum. The data strongly suggests that total aggrecan levels, i.e. aggrecan molecules containing G1 and/or G2 are lower in RA patients, and that RA patients have at least one specific subpopulation of aggrecan fragments, namely aggrecanse generated ³⁷⁴ARGSVI fragments. Further clinical studies are needed to investigate the potential of G1/G2 as a structure-related biochemical marker in destructive joint-diseases.

Successful etanercept therapy for refractory sacroiliitis in a patient with ankylosing spondylitis and mixed connective tissue disease

The concurrence of ankylosing spondylitis (AS) in a patient with mixed connective tissue disease (MCTD) is rarely described in the literature. Significant and sustained efficacy with tumor necrosis factor (TNF)-alpha blockers has been demonstrated in AS patients. However, evidence to date has revealed associated side effects, including antinuclear antibody induction and development of a lupus-like syndrome. Several authors have reported lupus-like manifestations in MCTD patients treated with TNF-alpha blockers used to control peripheral polyarthritis. In our case report, we demonstrate a good response to etanercept therapy for refractory sacroiliitis in a patient with coexisting AS and MCTD, without development of a lupus-like syndrome. This demonstrates that etanercept therapy may be an appropriate therapeutic agent for sacroiliitis in MCTD patients, as it is in AS alone.

Withania somnifera inhibits NF-kappaB and AP-1 transcription factors in human peripheral blood and synovial fluid mononuclear cells

Withania somnifera (WS) is an important herb with known antiinflammatory activity. Its molecular mechanism of action has not been investigated. The effect of a WS crude ethanol extract was studied on peripheral blood mononuclear cells of normal individuals and rheumatoid arthritis (RA) patients and synovial fluid mononuclear cells of RA patients in vitro. The WS extract significantly suppressed lipopolysaccharide (LPS) induced production of proinflammatory cytokines TNF-alpha, IL-1beta and IL-12p40 in normal individuals and RA patients, but had no effect on IL-6 production at the protein and transcript level. WS also suppressed LPS activated nitric oxide production in the mouse macrophage cell line, RAW 264.7. The extract inhibited nuclear translocation of the transcription factors NF-kappaB and AP-1 and phosphorylation of IkappaBalpha in normal and RA patients' mononuclear cells. HPLC analysis of the crude extract showed the presence of withaferin A and pure withaferin A also inhibited NF-kappaB translocation. The study demonstrated that the WS crude ethanol extract suppressed the production of proinflammatory molecules in vitro. This activity is partly through the inhibition of transcription factors NF-kappaB and AP-1 by the constituent withanolide. The role of additional constituents needs to be studied. Studies on the mechanism of action of the extract may yield potentially useful compounds for the treatment of inflammatory diseases.

Interleukin-17 gene expression in patients with rheumatoid arthritis

Interleukin-17 is a proinflammatory cytokine. Recent animal studies have shown that IL-17 plays a role in the initiation and progression of arthritis. However, whether IL-17 has a prominent role in human rheumatoid arthritis (RA) or not remains unclear. Here we investigated the role of IL-17 in patients with RA. cDNA was prepared from knee joint synovial tissues of RA (n = 11) and osteoarthritic (OA, n = 10) patients and PBMC of RA (n = 52) and healthy subjects (n = 34). IL-17 gene expression level was measured by real-time PCR, and was compared with various clinical parameters. IL-17 gene expression in synovial tissues of RA was similar to that in OA. IL-17 gene expression level in PBMC of RA patients was significantly higher than in the control. The response (changes in DAS) to two-week treatment with anti-TNF-alpha blockers (infliximab or etanercept) did not correlate with changes in IL-17 gene expression levels. The IL-17/TNF-alpha gene expression ratio at baseline (before treatment) tended to be lower in responders to the treatment. Expression of IL-17 gene in PBMC may be associated with the inflammatory process of RA. IL-17/TNF-alpha expression ratio is a potentially suitable marker of response to anti-TNF-alpha therapy.

Targeting TRAFs for Therapeutic Intervention

TNF-receptor associated factors (TRAFs) are the molecules that upon engagement of the TNF-receptor (TNFR) by a TNF-family ligand come first in contact with the activated TNFR, initially acting as docking molecules for kinases and other effector proteins that are recruited to the activated receptor. TRAFs later regulate the subcellular relocalization of the receptor-ligand complex and finally they modulate the extent of the response by controlling the degradation of key proteins in the pathway. In this chapter, we review the involvement of different TRAF family members in the etiology of a variety of pathologies and address the question of whether the use of TNFR-mimic-peptides or small molecule modulators targeting TRAFs might be suitable for therapeutic intervention, discussing the advantages and disadvantages of this strategy.

TNF-alpha, produced by feline infectious peritonitis virus (FIPV)-infected macrophages, upregulates expression of type II FIPV receptor feline aminopeptidase N in feline macrophages

The pathogenicity of feline infectious peritonitis virus (FIPV) is known to depend on macrophage tropism, and this macrophage infection is enhanced by mediation via anti-S antibody (antibody-dependent enhancement, ADE). In this study, we found that TNF-alpha production was increased with viral replication in macrophages inoculated with a mixture of FIPV and anti-S antibody, and demonstrated that this culture supernatant had feline PBMC apoptosis-inducing activity. We also demonstrated that the expression level of the FIPV virus receptor, feline aminopeptidase N (fAPN), was increased in macrophages of FIP cats. For upregulation of TNF-alpha and fAPN in macrophages, viral replication in macrophages is necessary, and their expressions were increased by ADE of FIPV infection. It was demonstrated that a heat-resistant fAPN-inducing factor was present in the culture supernatant of FIPV-infected macrophages, and this factor was TNF-alpha: fAPN expression was upregulated in recombinant feline TNF-alpha-treated macrophages, and FIPV infectivity was increased in these macrophages. These findings suggested that FIPV replication in macrophages increases TNF-alpha production in macrophages, and the produced TNF-alpha acts and upregulates fAPN expression, increasing FIPV sensitivity.

A rat pharmacokinetic/pharmacodynamic model for assessment of lipopolysaccharide-induced tumor necrosis factor-alpha production

INTRODUCTION

Tumor necrosis factor-alpha (TNFalpha) participates in many inflammatory processes. TNFalpha modulators show beneficial effects for the treatment of many diseases including rheumatoid arthritis. The purpose of this study was to validate a rat pharmacokinetic/pharmacodynamic (PK/PD) model for rapid assessment of drug candidates that intended to interrupt TNFalpha synthesis or release.

METHODS

Rats received intravenous (IV) or oral administrations of test article or dose vehicle, followed by LPS challenge. Plasma levels of test article and TNFalpha were determined. The areas under the concentration-time curves (AUC(drug) and AUC(TNFalpha)) were calculated. The overall percentage of inhibition on TNFalpha release in vivo was calculated by comparing AUC(TNFalpha) of the test article treated group against that for the vehicle control group.

RESULTS

The dosing vehicles tested in this study did not increase plasma TNFalpha level. At IV dose of up to 100 microg/kg, LPS did not alter the pharmacokinetics of the compound tested. Using a selective TNFalpha converting enzyme (TACE) inhibitor as model compound, this PK/PD model demonstrated its ability to correlate plasma test article concentration with its biological activity of lowering the LPS-induced TNFalpha plasma levels in vivo.

DISCUSSION

A rat PK/PD model for evaluation of the effect of drug candidates on LPS-induced TNFalpha synthesis and/or release has been investigated. This model provides integrated information on pharmacokinetics and in vivo potency of the test articles.

Enhanced integrative repair of the porcine meniscus in vitro by inhibition of interleukin-1 or tumor necrosis factor α

OBJECTIVE

To examine the hypotheses that increasing concentrations of interleukin-1 (IL-1) or tumor necrosis factor alpha (TNFalpha) inhibit the integrative repair of the knee meniscus in an in vitro model system, and that inhibitors of these cytokines will enhance repair.

METHODS

Explants (8 mm in diameter) were harvested from porcine medial menisci. To simulate a full-thickness defect, a 4-mm-diameter core was removed and reinserted. Explants were cultured for 14, 28, or 42 days in the presence of 0-1,000 pg/ml of IL-1 or TNFalpha. Explants were also cultured in the presence of IL-1 or TNFalpha with IL-1 receptor antagonist (IL-1Ra) or TNF monoclonal antibody (mAb). At the end of the culture period, biomechanical testing, cell viability, and histologic analyses were performed to quantify the extent of repair.

RESULTS

Mechanical testing revealed increased repair strength, cell accumulation, and tissue formation at the interface over time under control conditions. Pathophysiologic concentrations of both IL-1 and TNFalpha significantly decreased repair strength, cell migration, and tissue formation at the interface. The addition of IL-1Ra or TNF mAb to explants prevented the effects of IL-1 or TNFalpha, respectively.

CONCLUSION

Our findings document that physiologically relevant concentrations of IL-1 and TNFalpha inhibit meniscal repair in vitro and therefore may also inhibit meniscal repair during arthritis or following joint injury. The finding that IL-1Ra and TNF mAb promoted integrative meniscal repair in an inflammatory microenvironment suggests that intraarticular delivery of IL-1Ra and/or TNF mAb may be useful clinically to promote meniscal healing following injury.

Immunomodulatory activity of Semecarpus anacardium extract in mononuclear cells of normal individuals and rheumatoid arthritis patients

Semecarpus anacardium (SA) Linn. (family Anacardiaceae), is a plant well-known for its medicinal value in Ayurveda. The nut extracts of this plant have been traditionally used as antihelminthic, anti-fungal, anti-carcinogenic and in the treatment of nervous debilities and arthritis. In this study we have evaluated crude ethanolic extract of SA nuts for its anti-inflammatory activities in vitro using peripheral blood and synovial fluid mononuclear cells of healthy individuals and rheumatoid arthritis (RA) patients. SA extract inhibited the spontaneous and LPS induced production of proinflammatory cytokines IL-1beta and IL-12p40 but had no effect on TNF-alpha and IL-6 production, both at protein and mRNA level. The crude extract also suppressed LPS induced nuclear translocation of transcription factors, NF-kappaB and AP-1; the inhibition of NF-kappaB was through the inhibition of IkappaBalpha phosphorylation. The extract also suppressed LPS activated nitric oxide production in mouse macrophage cell line, RAW 264.7. Our results for the first time show that SA extract can inhibit proinflammatory cytokine production and demonstrate its mechanism of action.

Nonsurgical management of osteolysis: challenges and opportunities

Osteolysis remains a common mode of total hip arthroplasty failure. In vitro and animal models have been used to determine the pathophysiology of osteolysis by carefully dissecting the biochemical pathways leading to particulate wear debris and periprosthetic bone loss. Numerous cytokines and inflammatory mediators, including TNF-alpha and IL-1, are critical participants in this cascade and may represent prime targets for pharmacologic intervention. Osteoclasts, the end effector cells involved in the osteolytic process, also represent potential targets. Cell surface receptors on osteoclast precursors, such as receptor activator of NF-kappaB (RANK) (on osteoclasts) and RANK-ligand (RANKL) (on stromal cells), provide opportunities to arrest osteoclast maturation. Enhancing the naturally occurring osteoprotegerin is another recent attempt at modulating osteoclast behavior and a possible target for pharmacologic therapies. Other nonoperative strategies include intercepting tumor necrosis factor-alpha activity, interfering with the RANK-RANKL interaction necessary for osteoclast development and maturation, bisphosphonate therapy, and using viral vectors to deliver genes. Although each of these approaches has potential benefits, there are substantial challenges to effective implementation. Until there is convincing evidence of efficacy in human clinical trials, we recommend vigilant screening and appropriate surgery with component loosening or substantial likelihood of loosening, periprosthetic fracture, or major bone loss.

Elevated interferon gamma expression in the central nervous system of tumour necrosis factor receptor 1-deficient mice with experimental autoimmune encephalomyelitis

Inflammation in the central nervous system (CNS) can be studied in experimental autoimmune encephalomyelitis (EAE). The proinflammatory cytokines interferon-gamma (IFN-gamma) and tumour necrosis factor (TNF) are implicated in EAE pathogenesis. Signals through the type 1 TNF receptor (TNFR1) are required for severe EAE to develop, whereas deficiency in IFN-gamma or its receptor result in more severe EAE. We investigated IFN-gamma expression in TNFR1-deficient (TNFR1-/-) mice. We describe here that there were more IFN-gamma-secreting T cells present in the CNS of TNFR1-/- mice during EAE compared to wild-type (WT) mice, despite that clinical symptoms were mild, with delayed onset. There was greater expression of IL-12/23p40 by antigen-presenting cells in these mice, and in vitro, TNFR1-/- antigen-presenting cells induced greater secretion of IFN-gamma but not interleukin (IL)-17 when cultured with primed T cells than did WT antigen presenting cells. TNFR1-/- mice with EAE had significantly higher expression of CXCL10 mRNA (but not CCL5 mRNA) in the CNS compared to WT mice with EAE. These data demonstrate that IFN-gamma expression is enhanced in the CNS of TNFR1-/- mice with EAE and suggest that IFN-gamma levels do not necessarily correlate with EAE severity.

Polyamine depletion inhibits apoptosis following blocking of survival pathways in human chondrocytes stimulated by tumor necrosis factor-alpha

Chondrocyte apoptosis can be an important contributor to cartilage degeneration, thereby making it a potential therapeutic target in articular diseases. To search for new approaches to limit chondrocytic cell death, we investigated the requirement of polyamines for apoptosis favored by tumor necrosis factor-alpha (TNF), using specific polyamine biosynthesis inhibitors in human chondrocytes. The combined treatment of C-28/I2 chondrocytes with TNF and cycloheximide (CHX) resulted in a prompt effector caspase activation and internucleosomal DNA fragmentation. Pre-treatment of chondrocytes with alpha-difluoromethylornithine (DFMO), an ornithine decarboxylase (ODC) inhibitor, markedly reduced putrescine and spermidine content as well as the caspase-3 activation and DNA fragmentation induced by TNF and CHX. DFMO treatment also inhibited the increase in effector caspase activity provoked by TNF plus MG132, a proteasome inhibitor. DFMO decreased caspase-8 activity and procaspase-8 content, an apical caspase essential for TNF-induced apoptosis. Although DFMO increased the amount of active, phosphorylated Akt, inhibitors of the Akt pathway failed to restore the TNF-induced increase in caspase activity blunted by DFMO. DFMO also reduced the increase in caspase activity induced by staurosporine, but in this case Akt inhibition prevented the DFMO effect. Pre-treatment with CGP 48664, an S-adenosylmethionine decarboxylase (SAMDC) inhibitor markedly reduced spermidine and spermine levels, and provoked effects similar to those caused by DFMO. Finally DFMO was effective even in primary osteoarthritis (OA) chondrocyte cultures. These results suggest that the intracellular depletion of polyamines in chondrocytes can inhibit both the death receptor pathway by reducing the level of procaspase-8, and the apoptotic mitochondrial pathway by activating Akt.

Stabilization of the autoproteolysis of TNF-alpha converting enzyme (TACE) results in a novel crystal form suitable for structure-based drug design studies

The crystallization of TNF-alpha converting enzyme (TACE) has been useful in understanding the structure-activity relationships of new chemical entities. However, the propensity of TACE to undergo autoproteolysis has made enzyme handling difficult and impeded the identification of inhibitor soakable crystal forms. The autoproteolysis of TACE was found to be specific (Y352-V353) and occurred within a flexible loop that is in close proximity to the P-side of the active site. The rate of autoproteolysis was found to be proportional to the concentration of TACE, suggesting a bimolecular reaction mechanism. A limited specificity study of the S(1)' subsite was conducted using surrogate peptides and suggested substitutions that would stabilize the proteolysis of the loop at positions Y352-V353. Two mutant proteases (V353G and V353S) were generated and proved to be highly resistant to autoproteolysis. The kinetics of the more resistant mutant (V353G) and wild-type TACE were compared and demonstrated virtually identical IC(50) values for a panel of competitive inhibitors. However, the k(cat)/K(m) of the mutant for a larger substrate (P6 - P(6)') was approximately 5-fold lower than that for the wild-type enzyme. Comparison of the complexed wild-type and mutant structures indicated a subtle shift in a peripheral P-side loop (comprising the mutation site) that may be involved in substrate binding/turnover and might explain the mild kinetic difference. The characterization of this stabilized form of TACE has yielded an enzyme with similar native kinetic properties and identified a novel crystal form that is suitable for inhibitor soaking and structure determination.

Tetrathiomolybdate protects against cardiac damage by doxorubicin in mice

Cardiac toxicity is the limiting factor in therapy with doxorubicin, an otherwise useful cancer drug. In this article we detail our study of a mouse model of doxorubicin-induced cardiac toxicity in which, after 4 days' treatment, doxorubicin caused marked increases in plasma concentrations of creatine kinase, lactic dehydrogenase, and troponin I, indicators of cardiac injury; marked increases in the plasma concentrations of tumor necrosis factor-alpha and interleukin-1(beta), both inflammatory cytokines; and a marked increase in the plasma concentration of interleukin-2, an indicator of cytotoxic T-cell activation. Therapy with tetrathiomolybdate, designed to limit copper availability, eliminated almost all of the increases of these six parameters in plasma. The marked protection against cardiac injury by doxorubicin in tetrathiomolybdate-treated animals suggests that tetrathiomolybdate would be of use clinically in helping prevent doxorubicin toxicity in patients. In other preclinical work, it has been shown that tetrathiomolybdate potentiates the chemotherapeutic effect of doxorubicin in cancer, so a double benefit might accrue clinically from the combined use of tetrathiomolybdate and doxorubicin. The mechanism by which tetrathiomolybdate protects against doxorubicin toxicity is of considerable interest. Our working hypothesis, based on the inhibition of interleukin-2 by tetrathiomolybdate as shown here, is that tetrathiomolybdate interrupts the inflammatory cascade at the activated-T-lymphocyte stage.

Polyamine depletion inhibits NF-kappaB binding to DNA and interleukin-8 production in human chondrocytes stimulated by tumor necrosis factor-alpha

The activation of the NF-kappaB pathway by pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNFalpha), can be an important contributor for the re-programming of chondrocyte gene expression, thereby making it a therapeutic target in articular diseases. To search for new approaches to limit cartilage damage, we investigated the requirement of polyamines for NF-kappaB activation by TNFalpha in human C-28/I2 chondrocytes, using alpha-difluoromethylornithine (DFMO), a specific polyamine biosynthesis inhibitor. The NF-kappaB pathway was dissected by using pharmacological inhibitors or by expressing a transdominant IkappaBalpha super repressor. Treatment of C-28/I2 chondrocytes with TNFalpha resulted in a rapid enhancement of nuclear localization and DNA binding activity of the p65 NF-kappaB subunit. TNFalpha also increased the level and extracellular release of interleukin-8 (IL-8), a CXC chemokine that can have a role in arthritis, in an NF-kappaB-dependent manner. Pre-treatment of chondrocytes with DFMO, while causing polyamine depletion, significantly reduced NF-kappaB DNA binding activity. Moreover, DFMO also decreased IL-8 production without affecting cellular viability. Restoration of polyamine levels by the co-addition of putrescine circumvented the inhibitory effects of DFMO. Our results show that the intracellular depletion of polyamines inhibits the response of chondrocytes to TNFalpha by interfering with the DNA binding activity of NF-kappaB. This suggests that a pharmacological and/or genetic approach to deplete the polyamine pool in chondrocytes may represent a useful way to reduce NF-kappaB activation by inflammatory cytokines in arthritis without provoking chondrocyte apoptosis.

Infliximab for juvenile idiopathic arthritis-associated uveitis

BACKGROUND

Infliximab is a murine-human recombinant antitumour necrosis factor monoclonal antibody recently introduced for the treatment of autoimmune diseases in which tumour necrosis factor is thought to be a key mediator. Its role in the treatment of juvenile idiopathic arthritis-associated uveitis is as yet undefined.

METHODS

Six children with juvenile idiopathic arthritis-associated uveitis, inadequately controlled on currently available therapy, were treated with infliximab between September 2002 and November 2004. All children were required to remain on low-dose immunomodulatory treatment in conjunction with the infliximab. A retrospective review of two electronic databases containing details of ophthalmology and rheumatology visits was conducted.

RESULTS

In all six children, institution of infliximab therapy was associated with increased ease of management. Ocular inflammation and intraocular pressure control improved in all. It was also possible to reduce the dose or withdraw some glaucoma, steroid and other immunomodulatory drugs. Two children underwent intraocular surgery without noticeable flare of intraocular inflammation. No patient developed any serious systemic complications attributable to infliximab.

CONCLUSION

Infliximab may be a useful adjunct to the management of refractory juvenile idiopathic arthritis-associated uveitis. In our series it was associated with improved uveitis control and simplification of drug use as well as possibly improving safety of surgical intervention. This study suggests that its role is likely to be in conjunction with maintenance immunomodulatory treatment to provide more optimal disease control. Controlled studies are required to confirm its efficacy and safety, and the potential breadth of its use in uveitis and related disorders.

Prevention of the cryptic epitope SLAYGLR within osteopontin does not influence susceptibility to Candida albicans infection

The effect of an antiosteopontin antibody (M5 Ab) reacting with the SLAYGLR sequence within osteopontin on the host susceptibility to infection was investigated in a murine model of disseminated candidiasis. The treatment with anti-tumor necrosis factor alpha antibody enhanced fungal infection, while the treatment with M5 Ab did not affect the infection.

The complex role of the chemokine receptor CCR2 in collagen-induced arthritis: implications for therapeutic targeting of CCR2 in rheumatoid arthritis

CCR2 has been widely considered as a potential therapeutic target for autoimmune disease, particularly rheumatoid arthritis, and various CCR2 blocking agents have been developed, some of which have entered clinical trials. In this review, we examine the relevant information regarding the role of CCR2, and to a lesser extent of the closely related chemokine receptor CCR5, in the immunopathogenesis of collagen-induced arthritis, an animal model of rheumatoid arthritis. Experimental evidence showing that CIA is accelerated and exacerbated when CCR2 is genetically inactivated (knockout mice) or blocked with specific antibodies warrant additional investigations before the relevance of the findings in rodent models can be applied to human patients with RA.

Antithetical effects of hemicellulase-treated Agaricus blazei on the maturation of murine bone-marrow-derived dendritic cells

We report the effects of hemicellulase-treated Agaricus blazei (ABH) on the maturation of bone-marrow-derived dendritic cells (BMDCs). ABH activated immature BMDCs, inducing up-regulation of surface molecules, such as CD40, CD80 and major histocompatibility complex class I antigens, as well as inducing allogeneic T-cell proliferation and T helper type 1 cell development. However, unlike lipopolysaccharide (LPS), ABH did not stimulate the BMDCs to produce proinflammatory cytokines, such as interleukin-12 (IL-12) p40, tumour necrosis factor-alpha, or IL-1beta. In addition, ABH suppressed LPS-induced DC responses. Pretreatment of DCs with ABH markedly reduced the levels of LPS-induced cytokine secretion, while only slightly decreasing up-regulation of the surface molecules involved in maturation. ABH also had a significant impact on peptidoglycan-induced or CpG oligodeoxynucleotide-induced IL-12p40 production in DCs. The inhibition of LPS-induced responses was not associated with a cytotoxic effect of ABH nor with an anti-inflammatory effect of IL-10. However, ABH decreased NF-kappaB-induced reporter gene expression in LPS-stimulated J774.1 cells. Interestingly, DCs preincubated with ABH and then stimulated with LPS augmented T helper type 1 responses in culture with allogeneic T cells as compared to LPS-stimulated but non-ABH-pretreated DCs. These observations suggest that ABH regulates DC-mediated responses.

Decoy receptor 3 increases monocyte adhesion to endothelial cells via NF-kappa B-dependent up-regulation of intercellular adhesion molecule-1, VCAM-1, and IL-8 expression

Decoy receptor 3 (DcR3), a soluble receptor for FasL, LIGHT and TL1A, is highly expressed in cancer cells. We show that pretreatment of HUVECs with DcR3 enhances the adhesion of THP-1 and U937 cells and primary monocytes. A similar stimulatory effect of DcR3 on THP-1 adhesion was also observed in human microvascular endothelial cells (HMVECs). Flow cytometry and ELISA showed that DcR3-treated HUVECs exhibited significant increases in ICAM-1 and VCAM-1 expression. We also demonstrate the ability of DcR3 to stimulate the secretion of IL-8 by HUVECs. RT-PCR and reporter assays revealed that the expression of adhesion molecules and IL-8 are regulated at the level of gene transcription. Experiments with pyrrolidine dithiocarbamate indicated the involvement of an NF-kappaB signaling pathway. DcR3 was found to induce IkappaB kinase activation, IkappaB degradation, p65 nuclear translocation, and NF-kappaB DNA-binding activity. The enhancement by DcR3 of cell adhesion to HUVECs was not mimicked by the TL1A-Ab, which has been shown in our previous work to be a neutralizing Ab against TL1A, thereby inducing HUVECs angiogenesis. Moreover, DcR3-induced cell adhesion could be detected in human aortic endothelial cells (ECs) in which TL1A expression is lacking. Together, our data demonstrate that DcR3 increases monocyte adhesion to ECs via NF-kappaB activation, leading to the transcriptional up-regulation of adhesion molecules and IL-8 in ECs. This novel action appears not to be due to TL1A neutralization, but occurs through an as yet undefined target(s). This study implicates DcR3 in the relationship between inflammation and cancer development.

Role of osteopontin in amplification and perpetuation of rheumatoid synovitis

Osteopontin (OPN) is an extracellular matrix protein of pleiotropic properties and has been recently recognized as a potential inflammatory cytokine. In this study, we demonstrate, for the first time to our knowledge, that overexpression of OPN in synovial T cells is associated with local inflammatory milieu and that OPN acts as an important mediator in amplification and perpetuation of rheumatoid synovitis. The study revealed that mRNA expression of OPN was highly elevated in CD4(+) synovial T cells derived from patients with RA, which correlated with increased OPN concentrations in synovial fluid (SF). The pattern of OPN overexpression was confined to rheumatoid synovium and correlated with coexpression of selected OPN receptors in synovial T cells, including integrins alphav and beta1 and CD44. RA-derived SF stimulated the expression of OPN in T cells, which was attributable to IL-10 present in SF and abrogated by anti-IL-10 antibody. Among the more than 300 autoimmune and inflammatory response genes examined, OPN selectively induced the expression of proinflammatory cytokines and chemokines known to promote migration and recruitment of inflammatory cells. Furthermore, it was evident that OPN activated transcription factor NF-kappaB in mononuclear cells. The study has important implications for understanding the role of OPN in rheumatoid synovitis and other inflammatory conditions.

Differential expression and response to anti-TNFα treatment of infiltrating versus resident tissue macrophage subsets in autoimmune arthritis

Synovial macrophages play a pivotal role in the pathogenesis of chronic autoimmune arthritis by contributing to local inflammation and tissue damage and are therefore a primary target for therapeutic intervention. The aim of the present study was to investigate in more detail the relative contribution of different synovial macrophage subsets with potentially different inflammatory or anti-inflammatory functions by analysing the two most frequent forms of human autoimmune arthritis, spondyloarthropathy (SpA) and rheumatoid arthritis (RA). Both infiltrating macrophages from peripheral blood expressing myeloid-related proteins (MRP) 8 and 14, and resident tissue macrophages expressing CD163 were abundant in inflamed synovium. Whereas the global number of synovial macrophages was similar in both diseases, infiltrating macrophages were increased in the RA lining layer in contrast with resident tissue macrophages, which were more frequently observed in SpA. Soluble MRP8/MRP14 complexes, which were secreted locally in the joint during the infiltration process, were increased in the serum of arthritis patients and, in contrast with soluble CD163 shed from resident tissue macrophages, correlated well with global inflammatory parameters. Treatment in vivo with anti-TNFalpha had a rapid and pronounced effect on the infiltration of MRP-positive macrophages into tissues, as evidenced by histopathological analysis and serum MRP8/MRP14 levels. Taken together, these data support an important role for infiltrating versus resident tissue macrophages in human autoimmune synovitis and indicate that macrophage products such as soluble MRP8/MRP14 complexes are valuable biomarkers for the experimental and clinical monitoring of specific disease mechanisms in vivo.

Role of tumor necrosis factor alpha in asthma

Asthma is a heterogeneous disease in which various cytokines orchestrate airway inflammation. Tumor necrosis alpha (TNF-alpha) is a proinflammatory cytokine that has been implicated in the modulation of inflammation in various diseases, including asthma. Although TNF-alpha blocking strategies have been an effective therapeutic modality in diseases such as rheumatoid arthritis, their role in asthma and the effects of the blockade in asthma is poorly understood. This article examines the role of TNF-alpha in asthma and the effects of blocking TNF-alpha as a possible therapeutic option in patients with severe corticosteroid-dependent asthma.

The arachidonic acid 5-lipoxygenase inhibitor nordihydroguaiaretic acid inhibits tumor necrosis factor alpha activation of microglia and extends survival of G93A-SOD1 transgenic mice

Familial forms of amyotrophic lateral sclerosis (ALS) can be caused by mutations in copper, zinc-superoxide dismutase (SOD1). Mice expressing SOD1 mutants demonstrate a robust neuroinflammatory reaction characterized, in part, by up-regulation of tumor necrosis factor alpha (TNFalpha) and its primary receptor TNF-RI. In an effort to identify small molecule inhibitors of neuroinflammation useful in treatment of ALS, a microglial culture system was established to identify TNFalpha antagonists. Walker EOC-20 microglia cells were stimulated with recombinant TNFalpha, with or without inhibitors, and the cell response was indexed by NO2- output. Three hundred and fifty-five rationally selected compounds were included in this bioassay. The arachidonic acid 5-lipoxygenase (5LOX) and tyrosine kinase inhibitor nordihydroguaiaretic acid (NDGA), a natural dicatechol, was one of the most potent non-cytotoxic antagonists tested (IC50 8 +/- 3 microm). Investigation of the G93A-SOD1 mouse model for ALS revealed increased message and protein levels of 5LOX at 120 days of age. Oral NDGA (2500 p.p.m.) significantly extended lifespan and slowed motor dysfunction in this mouse, when administration was begun relatively late in life (90 days). NDGA extended median total lifespan of G93A-SOD1 mice by 10%, and life expectancy following start of treatment was extended by 32%. Disease-associated gliosis and cleaved microtubule-associated tau protein, an indicator of axon damage, were likewise reduced by NDGA. Thus, TNFalpha antagonists and especially 5LOX inhibitors might offer new opportunities for treatment of ALS.

Immunomodulation: the future of allergy and asthma treatment

PURPOSE OF REVIEW

As the prevalence of asthma and allergic disease increases around the world, it is clear that more effective therapies and disease-modifying agents are needed. Treatment for allergic disease is evolving with an increase in understanding of the etiology.

RECENT FINDINGS

The first immunomodulatory treatment was recently approved for use in the United States when the Food and Drug Administration approved the use of a humanized monoclonal anti-IgE antibody in patients with allergic asthma. Another strategy that has proved effective in a murine model is the downregulation of the whole immune system by targeting adhesion molecules, which has been evaluated in a recent human trial. Other strategies for the treatment of allergic diseases concentrate on refocusing the immune system away from an allergic-type response. These include the use of targeted therapies towards specific cytokines, cytokine receptors or chemokine receptors, and the use of specific bacterial DNA sequences (unmethylated cytosine-guanine dinucleotides). Finally, attention is being focused on possible therapies that may tilt the immune response to a non-allergic response by interfering with signaling molecule pathways.

SUMMARY

Immunomodulation will play a key role in future therapies for allergic disease. These treatment modalities may not only treat allergic disease, but also be beneficial in reducing the morbidity and mortality for which it is responsible.

The immunological aspects of latency in tuberculosis

A unique feature of Mycobacterium tuberculosis is its ability to exist in the granuloma of an asymptomatic host in a latent state that can subsequently reactivate to cause active disease. The latent state of infection poses a major obstacle to eradicating tuberculosis. In latent tuberculosis, the host immune response is capable of controlling the infection and yet falls short of eradicating the pathogen. That the host immune response contributes to the maintenance of latent tuberculous infection is supported by the observation that certain immunodeficient states, including those associated with the human immunodeficiency virus and tumor necrosis factor neutralization therapy, are associated with increased risks for developing reactivation disease. Latent tuberculosis is the product of a complex set of interactions between M. tuberculosis and the host immune response. The molecular basis for the persistence phenotype of M. Tuberculosis and the pertinent host immune mechanisms that contribute to the maintenance of tuberculous latency are just beginning to be understood. This review discusses the interactions between M. tuberculosis and the macrophage, the primary host cell that the tubercle bacillus parasitizes.

Role of tumour necrosis factor (TNF) in host defence against tuberculosis: implications for immunotherapies targeting TNF

Studies in mouse infection models clearly demonstrate tumour necrosis factor (TNF) to be a critical component of both the antibacterially protective and the inflammatory immune response to Mycobacterium tuberculosis. It is therefore not surprising that treatment of patients-for example, those with rheumatoid arthritis-with biological agents interfering with TNF activity have shown an increased risk of reactivating tuberculosis. However, conceivably, TNF targeting biological agents can be developed that because of their particular mode of action and their specific pharmacodynamics may be less likely to have this side effect.

Prostaglandin E2 inhibits TNF production in murine bone marrow-derived dendritic cells

Exposure to pathogens induces dendritic cells to release inflammatory cytokines and chemokines. The inflammatory response is controlled by endogenous agents such as anti-inflammatory cytokines, glucocorticoids, anti-inflammatory neuropeptides, and lipid mediators. This study is the first report on the inhibition by prostaglandin E2 (PGE2) of TNF release from bone marrow-derived dendritic cells stimulated with lipopolysaccharide (LPS), a TLR4 ligand, or peptidoglycan, a TLR2 ligand. The inhibition of TNF occurs at both mRNA and protein level. The inhibitory effect of PGE2 is mediated by the EP2 and EP4 receptors, and involves both PKA signaling and mediation by DC-derived IL-10. Intraperitoneal administration of PGE2 together with LPS results in a reduction in serum TNF and intracellular TNF in peritoneal exudate cells, compared to LPS alone. In addition, administration of PGE2 in vivo reduces the numbers of CD11c+ DCc that accumulate in the peritoneal cavity in response to LPS. The various implications of the PGE2-induced reduction in TNF are discussed.

Measuring Drug Action in the Cellular Context Using Protein-Fragment Complementation Assays

Cellular signal transduction occurs in the context of dynamic multiprotein complexes in highly ramified pathways. These complexes in turn interact with the cytoskeleton, protein scaffolds, membranes, lipid rafts, and specific subcellular organelles, contributing to the exquisitely tight regulation of their localization and activity. However, these realities of drug target biology are not addressed by currently available drug discovery platforms. In this article, we describe the use of protein-fragment complementation assays (PCAs) to assess drugs and drug targets in the context of their native environment. The PCA process allows for the detection of protein-protein complexes following the expression of full-length mammalian genes linked in-frame to polypeptide fragments of rationally dissected reporter genes. If cellular activity causes the association of two proteins linked to complementary reporter fragments, the interaction of the proteins of interest enables refolding of the fragments, which can then generate a quantifiable signal. Using a PCA based on a yellow fluorescent protein, we demonstrate that functional (p50/p65) complexes of the heterodimeric nuclear factor-kappaB transcription factor, as well as the transcription factor subunit p65 and its modulator IkappaBalpha, can be visualized and monitored in live cells. We observed similar responses of the PCA assays to the activities of the cognate endogenous proteins, including modulation by known agonists and antagonists. A proof-of-concept high throughput screen was carried out using the p50/p65 cell line, and potent inhibitors of this pathway were identified. These assays record the dynamic activity of signaling pathways in living cells and in real time, and validate the utility of PCA as a novel approach to drug discovery.