Cytokine inhibitors in the treatment of rheumatoid arthritis

The Minor Phytocannabinoid Delta-8-Tetrahydrocannabinol Attenuates Collagen-Induced Arthritic Inflammation and Pain-Depressed Behaviors

Patients with arthritis report using cannabis for pain management, and the major cannabinoid delta-9-tetrahydrocannabinol (Δ9-THC) has anti-inflammatory properties, yet the effects of minor cannabinoids on arthritis are largely unknown. The goal of the present study was to determine the antiarthritic potential of the minor cannabinoid delta-8-tetrahydrocannabinol (Δ8-THC) using the collagen-induced arthritis (CIA) mouse model. Adult male DBA/1J mice were immunized and boosted 21 days later with an emulsion of collagen and complete Freund's adjuvant. Beginning on the day of the booster, mice were administered twice-daily injections of Δ8-THC (3 or 30 mg/kg), the steroid dexamethasone (2 mg/kg), or vehicle for two weeks. Dorsal-ventral paw thickness and qualitative measures of arthritis were recorded daily, and latency to fall from an inverted grid was measured on alternating days, to determine arthritis severity and functional impairment. On the final day of testing, spontaneous wire-climbing behavior and temperature preference in a thermal gradient ring were measured to assess CIA-depressed behavior. The Δ8-THC treatment (30 mg/kg) reduced paw swelling and qualitative signs of arthritis. Δ8-THC also blocked CIA-depressed climbing and CIA-induced preference for a heated floor without producing locomotor effects but did not affect latency to fall from a wire grid. In alignment with the morphologic and behavioral assessments in vivo, histology revealed that Δ8-THC reduced synovial inflammation, proteoglycan loss and cartilage and bone erosion in the foot joints in a dose-dependent manner. Together, these findings suggest that Δ8-THC not only blocked morphologic changes but also prevented functional loss caused by collagen-induced arthritis. SIGNIFICANCE STATEMENT: Despite increasing use of cannabis products, the potential effects of minor cannabinoids are largely unknown. Here, the minor cannabinoid delta-8-tetrahydrocannabinol blocked the development of experimentally induced arthritis by preventing both pathophysiological as well as functional effects of the disease model. These data support the development of novel cannabinoid treatments for inflammatory arthritis.

Repurposed and investigational disease-modifying drugs in osteoarthritis (DMOADs)

In spite of a major public health burden with increasing prevalence, current osteoarthritis (OA) management is largely palliative with an unmet need for effective treatment. Both industry and academic researchers have invested a vast amount of time and financial expense to discover the first diseasing-modifying osteoarthritis drugs (DMOADs), with no regulatory success so far. In this narrative review, we discuss repurposed drugs as well as investigational agents which have progressed into phase II and III clinical trials based on three principal endotypes: bone-driven, synovitis-driven and cartilage-driven. Then, we will briefly describe the recent failures and lessons learned, promising findings from predefined post hoc analyses and insights gained, novel methodologies to enhance future success and steps underway to overcome regulatory hurdles.

Nanoparticle-Based Approaches towards the Treatment of Atherosclerosis

Atherosclerosis, being an inflammation-associated disease, represents a considerable healthcare problem. Its origin remains poorly understood, and at the same time, it is associated with extensive morbidity and mortality worldwide due to myocardial infarctions and strokes. Unfortunately, drugs are unable to effectively prevent plaque formation. Systemic administration of pharmaceuticals for the inhibition of plaque destabilization bears the risk of adverse effects. At present, nanoscience and, in particular, nanomedicine has made significant progress in both imaging and treatment of atherosclerosis. In this review, we focus on recent advances in this area, discussing subjects such as nanocarriers-based drug targeting principles, approaches towards the treatment of atherosclerosis, utilization of theranostic agents, and future prospects of nanoformulated therapeutics against atherosclerosis and inflammatory diseases. The focus is placed on articles published since 2015 with additional attention to research completed in 2019-2020.

Terpenes as possible drugs for the mitigation of arthritic symptoms - A systematic review

BACKGROUND

Arthritis is a syndrome associated with exacerbated inflammation, joint destruction and chronic pain and disability. Chronic treatment of arthritis is associated with several side effects and high abandonment. Therefore, there has been an ongoing search for alternative treatments to overcome these problems.

PURPOSE

Natural products, which are already widely used for their biological, cosmetic and pharmacotechnic properties, are a possible source for new drugs. Terpenes, a large class of organic compounds produced mainly by plants and trees, are a promising natural product and have already been shown to be effective in treating chronic pain, particularly of an inflammatory origin.

STUDY DESIGN AND METHODS

This review identifies the main terpenes with anti-arthritic activity reported in the last 10 years. A survey was conducted between December 2017 and June 2018 in the PUBMED, SCOPUS and Science Direct databases using combinations of the descriptors terpenes, arthritis and inflammation.

RESULTS

The results showed that terpenes have promising biological effects in relation to the treatment of arthritis, with the 24 terpenes identified in our survey being effective in the modulation of inflammatory mediators important to the physiopathology of arthritis, such as IL-6, IL-17, TNF-α, NFκB, and COX-2, among others. It is important to note that most of the studies used animal models, which limits, at least in part, the direct translation to humans of the experimental evidence produced by the studies.

CONCLUSION

Together, our finds suggest that terpenes can modulate the immuno-regulatory and destructive tissue events that underlie the clinical presentation and the progression of arthritis and are worthy of further clinical investigation.

Monoterpenes modulating cytokines - A review

Inflammatory response can be driven by cytokine production and is a pivotal target in the management of inflammatory diseases. Monoterpenes have shown that promising profile as agents which reduce the inflammatory process and also modulate the key chemical mediators of inflammation, such as pro and anti-inflammatory cytokines. The main interest focused on monoterpenes were to develop the analgesic and anti-inflammatory drugs. In this review, we summarized current knowledge on monoterpenes that produce anti-inflammatory effects by modulating the release of cytokines, as well as suggesting that which monoterpenoid molecules may be most effective in the treatment of inflammatory disease. Several different inflammatory markers were evaluated as a target of monoterpenes. The proinflammatory and anti-inflammatory cytokines were found TNF-α, IL-1β, IL-2, IL-5, IL-4, IL-6, IL-8, IL-10, IL-12 IL-13, IL-17A, IFNγ, TGF-β1 and IFN-γ. Our review found evidence that NF-κB and MAPK signaling are important pathways for the anti-inflammatory action of monoterpenes. We found 24 monoterpenes that modulate the production of cytokines, which appears to be the major pharmacological mechanism these compounds possess in relation to the attenuation of inflammatory response. Despite the compelling evidence supporting the anti-inflammatory effect of monoterpenes, further studies are necessary to fully explore their potential as anti-inflammatory compounds.

Therapeutic effect of acetazolamide, an aquaporin 1 inhibitor, on adjuvant-induced arthritis in rats by inhibiting NF-κB signal pathway

OBJECTIVES

Previous studies have shown that aquaporin 1 (AQP1) is up-regulated in synovium and cartilage of rheumatoid arthritis (RA) patients and that AQP1 may be involved in joint swelling and synovial inflammation. This study was aimed to investigate the potential therapeutic effect of acetazolamide (AZ, an AQP1 inhibitor) on rat adjuvant-induced arthritis (AIA) and explore its related mechanisms.

MATERIALS AND METHODS

Rat AIA was induced by complete Freund's adjuvant. The effect of AZ on rat AIA was evaluated by secondary hind paw swelling, arthritis index, TNF-α and IL-1β serum levels and histological examination of ankle joint. Proteoglycans expression and mRNA levels of type-II collagen (COII) and aggrecan in cartilage were measured by alcian blue staining and real-time PCR, respectively. The protein levels of AQP1, IκBα, phospho-IκBα (p-IκBα), NF-κB p65 and phospho-NF-κB p65 (p-NF-κB p65) in synovial tissues were detected by western blot.

RESULTS

AZ treatment could inhibit secondary hind paw swelling and arthritis index, reduce serum levels of TNF-α and IL-1β, and ameliorate pathological changes of ankle joint in AIA rats. AZ increased proteoglycans production and mRNA levels of COII and aggrecan in cartilage tissues. Moreover, AZ decreased AQP1 protein level and suppressed the activation of NF-κB pathway in synovium, indicated by inhibiting the degradation and phosphorylation of IκBα and reducing p-NF-κB p65 protein level.

CONCLUSIONS

AZ as an AQP1 inhibitor has a powerful therapeutic effect on rat AIA via inhibiting NF-κB activation, suggesting AQP1 inhibition might be of potential clinical interest in RA treatment.

Induction of interleukin-1 beta (IL-1β) is a critical component of lung inflammation during influenza A (H1N1) virus infection

Cytokine storm during influenza virus infection is recognized as a predictor of morbidity and mortality. To verify the cellular effects of influenza-induced cytokines in primary normal lung cells, human pulmonary microvascular endothelial cells (HMVECs) and lung fibroblast cells (MRC-5 cells) were infected with influenza virus H1N1. H1N1 infection induced the transcription of various genes encoding cytokines and chemokines such as interleukin-1 beta (IL-1β), IL-6, IL-8, IL-12A, tumor necrosis factor alpha (TNF-α), and chemokine (C-C motif) ligand 5 (CCL5) in both endothelial cells and lung fibroblasts. Among them, IL-1β induction by influenza infection increased the inflammation of lung cells; conversely, blockade of IL-1β signals with an IL-1β receptor antagonist or a neutralizing antibody alleviated influenza-driven inflammation. In conclusion, these data suggest that secreted IL-1β by the endothelial cells contributes to influenza-induced inflammation, and blockade of IL-1β signals is a potential treatment or therapeutic target for influenza-induced inflammation.

Certolizumab pegol (CDP870) for rheumatoid arthritis in adults

BACKGROUND

Tumour necrosis factor (TNF)-alpha inhibitors are beneficial for the treatment of rheumatoid arthritis (RA) in terms of reducing the risk of joint damage, improving physical function and improving quality of life. This Cochrane review is an update of a review of the treatment of RA with certolizumab pegol that was first published in 2011.

OBJECTIVES

To assess the clinical benefits and harms of certolizumab pegol (CDP870) in patients with RA who have not responded well to conventional disease-modifying anti-rheumatic drugs (DMARDs).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2014, Issue 5), MEDLINE, EMBASE, Scopus, TOXLINE, Web of Knowledge; websites of the US Food and Drug Administration (FDA) and European Medicines Evaluation Agency (EMEA); reference lists of articles; and searched http/clinicaltrials.gov. The searches were updated from 2009 (date of last search for the original review) to 5 June 2014.

SELECTION CRITERIA

Randomised controlled trials that compared certolizumab pegol with any other agent including placebo or methotrexate (MTX) in adult patients with active RA despite current or prior treatment with conventional disease-modifying anti-rheumatic drugs (DMARDs), such as MTX.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed search results, trial quality and extracted data. Disagreements were resolved by discussion or referral to a third author.

MAIN RESULTS

Eleven trials were included in this update. Ten (4324 patients) were included in the pooled analysis for benefits, five more than previously, and 10 (3711 patients) in the pooled analysis for harms, four more trials (1930 patients) than previously. The duration of follow-up varied from 12 to 52 weeks and the range of doses of certolizumab pegol varied from 50 to 400 mg given subcutaneously (sc). In phase III trials, the control was placebo plus MTX in five trials and placebo in four trials. The risk of bias of the included studies was assessed as low but there may have been a risk of attrition bias.Statistically significant improvements were observed at 24 weeks with the approved dose of 200 mg certolizumab pegol every other week, in 1) American College of Rheumatology (ACR) 50% improvement: 27% absolute improvement (95% CI 20% to 33%), NNT of 4 (95% CI 3 to 8), risk ratio (RR) 3.80 (95% CI 2.42 to 5.95); 2) the Health Assessment Questionnaire (HAQ): -12% absolute improvement (95% CI -9% to -14%), NNT of 6 (95% CI 5 to 8), mean difference (MD) - 0.35 (95% CI -0.43 to -0.26) (scale 0 to 3); 3) Disease Activity Score (DAS) remission improvement: absolute improvement 11% (95% CI 8% to 15%), NNT of 9 (95% CI 4 to 20), RR 8.47 (95% CI 4.15-17.28); and 4) radiological changes: erosion score (ES) absolute improvement -0.29% (95% CI -0.42% to -0.17%), NNT of 6 (95% CI 4 to 10), MD -0.67 (95% CI -0.96 to -0.38) (scale 0 to 230). Serious adverse events were statistically significantly more frequent for certolizumab pegol (200 mg every other week) with an absolute rate difference of 4% (95% CI 2% to 6%), NNTH of 32 (95% CI 17 to 88), Peto odds ratio (OR) 1.77 (95% CI 1.27 to 2.46). There was a statistically significant increase in all withdrawals in the placebo groups (for all doses and all follow-ups) with an absolute rate difference of -34% (95% CI -18% to -50%), NNTH of 4 (95% CI 3 to 5), NNTH of 4 (95% CI 3 to 5), RR 0.42 (95% CI 0.36 to 0.50); and there was a statistically significant increase in all withdrawals due to adverse events in the certolizumab groups (for all doses and all follow-up) with an absolute rate difference of 2% (95% CI 1% to 3%), NNTH of 55 (95% CI 27 to 238), Peto OR 1.66 (95% CI 1.15 to 2.37).The risk of bias was low and the quality of evidence was downgraded to moderate because of high rates of dropouts (> 20%) in most of the trials. We did not find any problems with inconsistency, indirectness, imprecision or publication bias.

AUTHORS' CONCLUSIONS

The results and conclusions did not change from the previous review. There is moderate-level evidence from randomised controlled trials that certolizumab pegol alone or combined with methotrexate is beneficial in the treatment of RA. Adverse events were more frequent with active treatment. We found a potential risk of serious adverse events.

Mechanism of the 24-hour rhythm of tumor necrosis factor-alpha formed by onset of rheumatoid arthritis

OBJECTIVE

Morning stiffness and plasma cytokine levels in rheumatoid arthritis (RA) patients exhibit 24-hour variations. Tumor necrosis factor-α (TNF-α) plays a central role in RA clinical conditions, including the invasion of inflammatory cells, destruction of cartilage, systemic inflammatory response and its levels show a 24-hour rhythm after the onset of RA. In this study, we investigated what cytokines and/or transcriptional factors are involved in the formation of 24-hour variations in TNF-α levels after the onset of RA using MRL/Mpj-Tnfrsf6(lpr) (MRL/lpr) mice.

METHOD

Blood was drawn at six different times from MRL/lpr mice to measure cytokines, serum amyloid A (SAA), IgG rheumatoid factor (IgG-RF) and corticosterone levels. Cytokine and transcriptional factor levels at the different times were measured in 10- and/or 15-week-old MRL/lpr mice. The promoter activity of TNF-α by lymphotoxins (LTs) was investigated using a dual-luciferase assay.

RESULTS

SAA and TNF-α concentrations clearly exhibited 24-hour rhythms with higher levels at the light phase and lower levels at the dark phase after RA crisis. The expression of LT-α and LT-β showed significant 24-hour rhythms in 15-week-old MRL/lpr mice and the phases of LT-α and LT-β levels were antiphase compared with that of TNF-α. AP-1 binding sites were found in LT-α and LT-β promoter regions, and jun mRNA expression corresponded to LT-α and LT-β levels. TNF-α promoter activity was decreased due to the co-transfection of LT-α and LT-β.

CONCLUSION

LT-α and LT-β controls the 24-hour rhythm in TNF-α levels after the onset of RA in order to suppress TNF-α promoter activity.

Anti-inflammatory properties of a novel peptide interleukin 1 receptor antagonist

Background

Interleukin 1 (IL-1) is implicated in neuroinflammation, an essential component of neurodegeneration. We evaluated the potential anti-inflammatory effect of a novel peptide antagonist of IL-1 signaling, Ilantide.

Methods

We investigated the binding of Ilantide to IL-1 receptor type I (IL-1RI) using surface plasmon resonance, the inhibition of Il-1β-induced activation of nuclear factor κB (NF-κB) in HEK-Blue cells that contained an IL-1β-sensitive reporter, the secretion of TNF-α in macrophages, protection against IL-1-induced apoptosis in neonatal pancreatic islets, and the penetration of Ilantide through the blood–brain barrier using competitive enzyme-linked immunosorbent assay (ELISA). We studied the effects of the peptide on social behavior and memory in rat models of lipopolysaccharide (LPS)- and amyloid-induced neuroinflammation, respectively, and its effect in a rat model of experimental autoimmune enchephalomyelitis.

Results

Ilantide bound IL-1RI, inhibited the IL-1β-induced activation of NF-κB, and inhibited the secretion of TNF-α in vitro. Ilantide protected pancreatic islets from apoptosis in vitro and reduced inflammation in an animal model of arthritis. The peptide penetrated the blood–brain barrier. It reduced the deficits in social activity and memory in LPS- and amyloid-treated animals and delayed the development of experimental autoimmune enchephalomyelitis.

Conclusions

These findings indicate that Ilantide is a novel and potent IL-1RI antagonist that is able to reduce inflammatory damage in the central nervous system and pancreatic islets.

NF-κB signaling and bone resorption

The transcription factor NF-κB is a family of proteins involved in signaling pathways essential for normal cellular functions and development. Deletion of various components of this pathway resulted with abnormal skeletal development. Research in the last decade has established that NF-κB signaling mediates RANK ligand-induced osteoclastogenesis. Consistently, it was shown that inhibition of NF-κB was an effective approach to inhibit osteoclast formation and bone resorptive activity. Identification of the molecular machinery underlying NF-κB activation permitted osteoclast-specific deletion of the major components of this pathway. As a result, it was clear that deletion of members of the proximal IKK kinase complex and the distal NF-κB subunits and downstream regulators affected skeletal development. These studies provided several targets of therapeutic intervention in osteolytic diseases. NF-κB activity has been also described as the centerpiece of inflammatory responses and is considered a potent mediator of inflammatory osteolysis. Indeed, inflammatory insults exacerbate physiologic RANKL-induced NF-κB signals leading to exaggerated responses and to inflammatory osteolysis. These superimposed NF-κB activities appear to underlie several bone pathologies. This review will describe the individual roles of NF-κB molecules in bone resorption and inflammatory osteolysis.

MAPKAP Kinase 2 (MK2) as a Target for Anti-inflammatory Drug Discovery

Despite the success of anti-TNFα biologicals, there remains a significant unmet need for novel oral anti-inflammatory drugs for the treatment of rheumatoid arthritis and related diseases. Vigorous exploration of many potential targets for inhibition of, for example, pro-inflammatory cytokine production has led to efforts to find inhibitor leads targeting many enzymes including the p38α substrate kinase MK2. MK2 has a key role in the production of several pro-inflammatory cytokines, and studies with knockout animals and inhibitor leads support the promise of MK2 as an anti-inflammatory target. However, MK2 has additional biological roles such as in cell cycle checkpoint control, suggesting caution in the use of MK2 inhibitors for chronic non-life-threatening clinical indications such as inflammation. MK2 inhibitor lead identification and optimization efforts in several labs have resulted in a variety of potent and specific lead molecules, some of which display in-vivo activity. However, potency loss from enzyme to cell, and cell to in vivo, is commonly significant. Further, poor enzyme to cell potency correlations are also common for MK2 lead chemical series, suggesting uncontrolled confounding factors in lead inhibitor properties, or that the biological roles of MK2 and related enzymes may still be poorly understood. While further efforts in identification of MK2 inhibitors may yet yield viable drug leads, efforts to date suggest caution with this target.

Certolizumab pegol (CDP870) for rheumatoid arthritis in adults

BACKGROUND

TNF-alpha inhibitors have been shown to reduce the risk of joint damage and improve physical function and quality of life in people with rheumatoid arthritis (RA). This is the first Cochrane review of certolizumab pegol, a new TNF-alpha inhibitor.

OBJECTIVES

To assess the effectiveness and safety of certolizumab pegol (CDP870) in patients with RA who have not responded well to conventional disease modifying anti-rheumatic drugs (DMARDs).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2009, Issue 3),  MEDLINE (1966 to November 2009), EMBASE (1966 to November 2009), Scopus (January 2004 to November 2009), TOXLINE (until November 2009), Web of Knowledge (until November 2009); websites of the US Food and Drug Administration (FDA) and European Medicines Evaluation Agency (EMEA) (until November 2009), and reference lists of articles.

SELECTION CRITERIA

Randomised controlled trials that compared certolizumab pegol with any other agent including placebo or methotrexate (MTX) in adult RA patients with active rheumatoid arthritis despite current or prior treatment with conventional DMARDs, such as methotrexate (MTX).

DATA COLLECTION AND ANALYSIS

Two authors independently assessed search results, trial quality and extracted data.

MAIN RESULTS

Five trials were included. We included in the analysis 2394 people for effectiveness and 2094 people for safety. The duration of follow-up was from 12 to 52 weeks, and the range of doses of certolizumab pegol were from 50 to 400 mg subcutaneously (sc). In three trials the control was placebo plus methotrexate (MTX) and in two trials it was just placebo. Significant improvements were observed at 24 weeks with the approved dose of 200 mg certolizumab pegol: American College of Rheumatology (ACR) 50% improvement: risk ratio (RR) 6.01 (95% CI 3.84 to 9.40) with an absolute benefit of 29% (95% CI 25% to 34%), number needed to treat to benefit (NNTB) of 4 (3 to 5) and the Health Assessment Questionnaire (HAQ) mean difference (MD) - 0.39 (95% CI -0.45 to -0.32) (scale 0 to 3). At 52 weeks the results were quite similar: ACR 50% improvement RR 5.27 (95% CI 3.19 to 8.71), HAQ mean difference (MD) - 0.42 (95% CI -0.52 to -0.32). Serious adverse events were more frequent for certolizumab pegol 200 mg, Peto OR 2.02 (95% CI 1.24 to 3.30). The most common adverse events with certolizumab pegol 200 mg were: upper respiratory tract infections, Peto OR 2.21 (95% CI 1.15 to 4.25); hypertension, Peto OR 2.81 (95% CI 1.38 to 5.75); and nasopharyngitis, Peto OR 2.71 (95% CI 1.30 to 5.66).

AUTHORS' CONCLUSIONS

With an overall high grade of evidence this review revealed an improvement of clinical results (ACR50, 28 joint disease activity score (DAS-28) remission and HAQ scores) with certolizumab pegol. Adverse events were more frequent with certolizumab; there was a statistically significant increase in the number of serious adverse events, infections and hypertension.

Inhibitors of p38 suppress cytokine production in rheumatoid arthritis synovial membranes: does variable inhibition of interleukin-6 production limit effectiveness in vivo?

OBJECTIVE

The activity of p38 MAPK regulates lipopolysaccharide (LPS)-stimulated production of key proinflammatory cytokines such as tumor necrosis factor α (TNFα). Consequently, p38 MAPK inhibitors have attracted considerable interest as potential treatments of rheumatoid arthritis (RA), and studies in murine models of arthritis have yielded promising results. However, the performance of several compounds in human clinical trials has been disappointing. At present, the reason for this poor performance is unclear. The aim of this study was to examine the effects of p38 inhibitors on both diseased and normal human tissue and cells, in order to test whether this kinase still plays a critical role in cytokine production under conditions of chronic inflammation.

METHODS

Proinflammatory and antiinflammatory cytokine production was monitored after treatment of primary human monocytes, macrophages, and RA synovial membrane cultures with p38 MAPK inhibitor compounds. The following 3 inhibitors were used in these studies: SB-203580 (inhibits the α and β isoforms), BIRB-796 (inhibits the α, β, γ, and δ isoforms), and a novel, structurally distinct p38 MAPK inhibitor, SB-731445 (inhibits the α and β isoforms).

RESULTS

SB-731445 and SB-203580 produced profound inhibition of spontaneous production of proinflammatory cytokines (TNFα and interleukin-1 [IL-1]) in both RA membrane cultures and LPS-stimulated primary human monocytes. However, this and other p38 MAPK inhibitors produced a significant increase in IL-6 production by LPS-stimulated primary human macrophages and a decrease in IL-10 production by all cell types examined.

CONCLUSION

The potentially proinflammatory consequences of these activities (decreased IL-10 production and increased IL-6 production) may offer some explanation for the inability of p38 MAPK inhibitors to provide the therapeutic benefit that had been hoped for in RA.

Hesperidin suppresses adjuvant arthritis in rats by inhibiting synoviocyte activity

The present study was designed to investigate the effect of hesperidin on rat adjuvant arthritis (AA) and to elucidate the involvement of synoviocytes in this process. Freund's complete adjuvant was used to induce AA in rats. Secondary paw swelling and the index of immune organs of AA rats were measured. Macrophage-like synoviocytes were separated by the method of collagenase and trypsin digestion. Synoviocyte proliferation was assayed by MTT assay. TNF-alpha, IL-1beta and IL-10 production of synoviocytes were examined with ELISA. The levels of TNF-alpha, IL-1beta, IL-10 mRNA were determined using RT-PCR. It was found that intragastric hesperidin administration (80, 160 mg/kg) significantly inhibited secondary paw swelling and restored the index of immune organs of AA rats. Furthermore, synoviocyte proliferation in AA rats was apparently suppressed after hesperidin treatment, which was accompanied by decreased transcription as well as production of TNF-alpha and IL-1beta from synoviocytes. Hesperidin also markedly increased IL-10 at both protein and transcription levels in AA rats. In aggregate, the above results demonstrate that hesperidin has a therapeutic effect on AA and the mechanisms are partly related to inhibiting synoviocyte activity and modulating inflammatory cytokine production of synoviocytes which play a crucial role in the pathogenesis of AA.

2,4-Diaminopyrimidine MK2 inhibitors. Part II: Structure-based inhibitor optimization

We describe structure-based optimization of a series of novel 2,4-diaminopyrimidine MK2 inhibitors. Co-crystal structures (see accompanying Letter) demonstrated a unique inhibitor binding mode. Resulting inhibitors had IC(50) values as low as 19nM and moderate selectivity against a kinase panel. Compounds 15, 31a, and 31b inhibit TNFalpha production in peripheral human monocytes.

Platelets as immune cells: bridging inflammation and cardiovascular disease

Beyond an eminent role in hemostasis and thrombosis, platelets are characterized by expert functions in assisting and modulating inflammatory reactions and immune responses. This is achieved by the regulated expression of adhesive and immune receptors on the platelet surface and by the release of a multitude of secretory products including inflammatory mediators and cytokines, which can mediate the interaction with leukocytes and enhance their recruitment. In addition, platelets are characterized by an enormous surface area and open canalicular system, which in concert with specialized recognition receptors may contribute to the engulfment of serum components, antigens, and pathogens. Platelet-dependent increases in leukocyte adhesion may not only account for an exacerbation of atherosclerosis, for arterial repair processes, but also for lymphocyte trafficking during adaptive immunity and host defense. This review compiles a selection of platelet-derived tools for bridging inflammation and vascular disease and highlights the molecular key components governing platelet-mediated mechanisms operative in immune surveillance, vascular remodeling, and atherosclerosis.

Vaccination against IL-17 suppresses autoimmune arthritis and encephalomyelitis

Interleukin 17 is a T cell-derived cytokine that induces the release of pro-inflammatory mediators in a wide range of cell types. Recently, a subset of IL-17-producing T helper cells (Th17) distinct from Th1 and Th2 cells has been described, which constitutes a new T cell polarization state. Aberrant Th17 responses and overexpression of IL-17 have been implicated in a number of autoimmune disorders including rheumatoid arthritis and multiple sclerosis. Molecules blocking IL-17 such as IL-17-specific monoclonal antibodies have proved to be effective in ameliorating disease in animal models. Hitherto, active immunization targeting IL-17 is an untried approach. Herein we explore the potential of neutralizing IL-17 by active immunization using virus-like particles conjugated with recombinant IL-17 (IL-17-VLP). Immunization with IL-17-VLP induced high levels of anti-IL-17 antibodies thereby overcoming natural tolerance, even in the absence of added adjuvant. Mice immunized with IL-17-VLP had lower incidence of disease, slower progression to disease and reduced scores of disease severity in both collagen-induced arthritis and experimental autoimmune encephalomyelitis. Active immunization against IL-17 therefore represents a novel therapeutic approach for the treatment of chronic inflammatory diseases.

Nuclear factor kappa-B blockade reduces skeletal muscle degeneration and enhances muscle function in Mdx mice

Duchenne muscular dystrophy (DMD) is a progressive muscle-wasting disease due to a mutation in the dystrophin gene and the consequential protein deficiency in muscle. How the lack of the sarcolemmal protein dystrophin gives rise to the final disease status is still not clear. Several evidences suggest a role of nuclear factor kappa-B (NF-kappaB), a pleiotropic transcription factor, in muscle degeneration and regeneration in DMD patients and mdx mice. We investigated the effects of NF-kappaB blocking by pyrrolidine dithiocarbamate (PDTC), a well-known NF-kappaB inhibitor, on dystrophic process in mdx mice. Five-week-old mdx and wild-type mice received three times a week for 5 weeks either PDTC (50 mg/kg) or its vehicle. PDTC treatment: (i) increased forelimb strength (+20%; P < 0.05) and strength normalized to weight (+24%; P < 0.05) and a decreased fatigue percentage (-61%; P < 0.05) in mdx mice, (ii) blunted the augmented NF-kappaB nuclear binding activity and the enhanced TNF-alpha expression in dystrophic muscles (P < 0.01), (iii) at a quantitative morphological evaluation of extensor digitorum longus (EDL) and biceps muscles, increased area with normal fibers (P < 0.05, in EDL), reduced muscle necrosis (P < 0.05 in biceps; P < 0.01 in EDL), and enhanced muscle regeneration (P < 0.01, in biceps). Our data support the hypothesis that NF-kappaB contributes to the perpetuation of the dystrophic damage and show that its blockade produces beneficial effects on functional, biochemical, and morphological parameters in mdx mice. Most importantly, these new findings may have clinical implications for the pharmacological treatment of patients with DMD.

Interleukin-18 bioactivity: a novel target for immunopharmacological anti-inflammatory intervention

Interleukin-18 is a member of the interleukin-1 family of cytokines with pro-inflammatory and tumor-suppressive properties. Its ability to potently enhance the production of interferon-gamma indicates in particular the crucial function of interleukin-18 as an immunomodulatory molecule. In fact, high levels of interleukin-18 are detected in human diseases associated with immunoactivation including viral or bacterial infections and chronic inflammation. Animal models suggest suppression of interleukin-18 bioactivity as a novel therapeutic concept specifically for the treatment of chronic inflammatory diseases such as rheumatoid arthritis, Crohn's disease, and psoriasis. Here we introduce into the biology of interleukin-18 and review immunopharmacological strategies that aim at reducing interleukin-18 bioactivity in human disease.

Immunosuppressants in advanced clinical development for organ transplantation and selected autoimmune diseases

Immunosuppressants dampen the immune response or restore balance among immune system components. They are primarily used to prevent allograft rejection after organ transplantation and to prevent or treat disease flares in autoimmune diseases. Immunosuppressants available at present include the calcineurin inhibitors (cyclosporin, tacrolimus), antimetabolites (azathioprine, leflunomide, methotrexate, mycophenolate mofetil), antiproliferatives (sirolimus), monoclonal antibodies to T lymphocyte (basiliximab, daclizumab, muromonab-CD3) and anticytokines (anakinra, etanercept, infliximab). The immunosuppressive market grows at a rate of > 10% yearly, with total sales in 2001 of US$2.7 billion. Immunotherapy in transplantation and autoimmune diseases is tending towards the use of multi-drug regimens tailored for the individual patient. At least 23 new immunosuppressants are currently in advanced clinical testing or preregistration, and can be divided into three groups. First, emerging drugs targeting intracellular ligands in immune cells are primarily analogues of currently-marketed agents, which attempt to provide improved pharmaceutical or safety profiles compared with the prototype compound. They are largely being developed in organ transplantation. Second, emerging drugs targeting cell surface ligands on immune cells attempt to antagonise novel molecular sites to interfere with immune cell activation via costimulatory signals, immune cell adhesion to tissues or the vasculature and immune cell trafficking. These agents are being primarily developed in rheumatoid arthritis, psoriasis and/or multiple sclerosis. Finally, emerging drugs acting as anticytokines, which largely follow on from the success of those on the market, by antagonising the function of tumour necrosis factor or a narrow selection of interleukins. All are being assessed in rheumatoid arthritis. Drug development of immunosuppressants is increasingly attempting to intervene in disease progression over the long term. These efforts bring with them trial design and regulatory issues, such as what markers can be used as trial outcome measures, over what duration do trials need to be conducted and what labelling claims are allowed. With the intensive activity in this field, it is likely that several new drugs will reach the market in the coming decade. One caveat, however, is that emerging immunosuppressants that are likely to capture a reasonable share of this increasingly-fragmented market must demonstrate the ability to achieve disease remission or long-term slowing of disease progression.

Anti-TNFalpha (Remicade) therapy protects dystrophic skeletal muscle from necrosis

Necrosis of skeletal muscle fibers in the lethal childhood myopathy Duchenne muscular dystrophy (DMD) results from defects in the cell membrane-associated protein, dystrophin. This study tests the novel hypothesis that the initial sarcolemmal breakdown resulting from dystrophin deficiency is exacerbated by inflammatory cells and that cytokines, specifically tumor necrosis factor-alpha (TNFalpha), contribute to muscle necrosis. To block in vivo TNFalpha bioactivity, young dystrophic mdx mice (a model for DMD) were injected weekly from 7 days of age with the anti-TNFalpha antibody Remicade before the onset of muscle necrosis and dystropathology that normally occurs at 21 days postnatally. The extent of inflammation, muscle necrosis, and myotube formation was measured by histological analysis from 18 to 28 days and muscle damage was also visualized by penetration of Evans blue dye into myofibers. Data from Remicade-treated and control mdx mice were compared with mdx/TNFalpha-/- mice that lack TNFalpha. Pharmacological blockade of TNFalpha activity with Remicade clearly delayed and greatly reduced the breakdown of dystrophic muscle, in marked contrast to the situation in mdx and mdx/TNFalpha-/- mice. Remicade had no adverse effect on new muscle formation. Remicade is a highly specific anti-inflammatory intervention, and clinical application to muscular dystrophies is suggested by this marked protective effect against skeletal muscle breakdown.

IL-18BPa:Fc cooperates with immunosuppressive drugs in human whole blood

The proinflammatory cytokine interleukin (IL)-18 appears to be involved in the pathogenesis of diseases associated with immunoactivation and inflammation. Consequently, blockage of IL-18 bioactivity by use of IL-18 binding protein (IL-18 BP) is likely a promising therapeutic concept. In the present study, we investigated immunomodulatory activities of IL-18 BPa:Fc in human whole blood cultures. We report that IL-18 BPa:Fc (200 ng/mL) significantly inhibited lipopolysaccharide (LPS, 10 ng/mL)/IL-12 (5 ng/mL)-induced release of interferon-gamma (IFNgamma) and matrix metalloproteinase-9 (MMP-9) from whole blood cultures of healthy donors. Notably, IL-18 BPa:Fc (200 ng/mL) further reinforced dexamethasone (5 nM)- or mycophenolic acid (2 microM)-mediated reduction of LPS/IL-12-induced IFNgamma production by an additional 50.5 or 49.9%, respectively. To investigate effects of IL-18 BP:Fc in the context of autoimmune diseases, experiments were performed with whole blood obtained from patients with systemic lupus erythematosus or Wegener's granulomatosis undergoing immunosuppressive therapy. After ex vivo stimulation with LPS (10 ng/mL), production of IFNgamma and MMP-9 was determined. Both mediators likely contribute to renal inflammation frequently seen in these diseases. In accord with the aforementioned data, LPS (10 ng/mL)-induced IFNgamma was significantly reduced by coincubation with IL-18 BPa:Fc at 200 ng/mL. IL-18 BPa:Fc also inhibited production of MMP-9. The present data demonstrate that IL-18 BPa:Fc has the potential to amplify anti-inflammatory actions of immunosuppressive drugs, and thus may prove to be a valuable novel pharmacological component in the treatment of human autoimmune diseases.

Histamine releasing peptide (HRP) has proinflammatory effects and is present at sites of inflammation

Albumin, the most abundant plasma protein, readily enters sites of inflammation during the period of increased vascular permeability. There it encounters proteases released from mast cells and invading leukocytes which earlier work has shown can act on albumin to liberate the peptide, histamine releasing peptide (HRP), first identified and named by its ability to stimulate histamine release from isolated mast cells. In this report we show that HRP releases histamine from cutaneous mast cells in vivo resulting in increased vascular permeability and persistent edema while in vitro, HRP promotes chemotaxis of leukocytes and enhances macrophage phagocytosis. Moreover, we show that the level of HRP is increased with the induction of an acute cutaneous inflammatory response in rats, that HRP is present at sites of acute and chronic inflammation in humans and that HRP is rapidly degraded by proteases thereby limiting its action to the area of its generation. We suggest that HRP is a pro-inflammatory peptide that helps amplify and perpetuate the inflammatory response. Inhibitors of inflammatory proteases or antagonists that block the action of peptides like HRP may, therefore, be useful in breaking the cycle of inflammation.

Interleukin-10 and the regulation of mitogen-activated protein kinases: are these signalling modules targets for the anti-inflammatory action of this cytokine?

The many specific, yet overlapping and redundant activities of individual cytokines have been the basis for current concepts of therapeutical intervention. Cytokines are powerful two-edged weapons that can trigger a cascade of reactions and may show activities that often go beyond the single highly specific property that it is hoped they possess. Nevertheless, it can be stated that our new, though burgeoning, understanding of the biological mechanisms governing cytokine actions is an important contribution to medical knowledge. The crucial role of the anti-inflammatory cytokine, interleukin (IL)-10, in regulating potential molecular pathway mediating injury and cell death has attracted paramount attention in recent years. In this respect, the mitogen-activated protein kinase (MAPK) components have emerged as potential signalling cascades that regulate a plethora of cell functions, including inflammation and cell death. The biochemistry and molecular biology of cytokine actions, particularly IL-10, explain some well known and sometimes also some of the more obscure clinical aspects of the evolution of diseases.

Geldanamycin inhibits the production of inflammatory cytokines in activated macrophages by reducing the stability and translation of cytokine transcripts

OBJECTIVE

Heat-shock protein 90 (Hsp90) is critical in the intracellular signaling pathways that promote inflammatory cytokine production. Geldanamycin (GD) is a benzoquinone ansamycin that inhibits the function of Hsp90. GD inhibits the production of tumor necrosis factor alpha (TNFalpha) in activated macrophages and suppresses the progression of adjuvant-induced arthritis and experimental allergic encephalomyelitis in rodents. GD has been used to investigate the mechanisms by which Hsp90 regulates inflammatory cytokine production.

METHODS

The macrophage cell line RAW264.7 (or primary peritoneal macrophages) was activated with lipopolysaccharide in the absence or presence of GD. The effect of GD on the transcription, stability, and translation of inflammatory cytokine messenger RNA (mRNA) was determined using nuclear run-on assays, mRNA decay assays, and sucrose gradient polysome profiles, respectively.

RESULTS

Our data revealed that GD potently inhibits the production of TNFalpha, interleukin-6 (IL-6), and IL-1beta in activated macrophages. Although GD did not significantly reduce the transcription of inflammatory cytokine mRNA, it significantly decreased the stability of these transcripts. Polysome profiles indicated that GD also inhibited the translation of TNFalpha and IL-6 transcripts. These effects may be due, in part, to inhibition of p38 mitogen-activated protein kinase, a kinase known to regulate the stability and translation of inflammatory cytokine transcripts.

CONCLUSION

These results indicate that the function of Hsp90 is important in the posttranscriptional control of inflammatory cytokine production.

Fenfluramine-induced immunosuppression: an in vivo analysis

We examined the immunomodulatory potential of acute fenfluramine administration, by measuring production of the pro-inflammatory cytokines interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha in response to an in vivo challenge with bacterial lipopolysaccharide in rats. Fenfluramine (2.5-10 mg/kg) suppressed tumor necrosis factor-alpha production, but only fenfluramine (5 and 10 mg/kg) suppressed interleukin-1beta production. Fenfluramine (10 mg/kg)-induced suppression of interleukin-1beta and tumor necrosis factor-alpha production persisted for 6 and 24 h, respectively. Using in vitro analyses, we demonstrated that the immunosuppressive effect of fenfluramine was not due to a direct effect on immune cells. As fenfluramine activates the hypothalamic pituitary adrenal axis, we examined the ability of the glucocorticoid receptor antagonist mifepristone to block fenfluramine-induced immunosuppression. However, mifepristone (10 mg/kg) failed to attenuate the suppressive effect of fenfluramine on interleukin-1beta and tumor necrosis factor-alpha production, indicating that glucocorticoids do not mediate fenfluramine-induced immunosuppression. We also assessed the effect of fenfluramine on production of the anti-inflammatory cytokine interleukin-10, as interleukin-10 can suppresses pro-inflammatory cytokine production. Fenfluramine (10 mg/kg) increased interleukin-10 production following an in vivo lipopolysaccharide challenge. However, the ability of fenfluramine to suppress tumor necrosis factor-alpha production cannot be accounted for by increased interleukin-10 production, as pretreatment with the beta-adrenoceptor antagonist nadolol completely blocked the increase in interleukin-10 without altering the suppression of tumor necrosis factor-alpha induced by fenfluramine. Taken together, these data demonstrate that fenfluramine promotes an immunosuppressive cytokine phenotype in vivo. The suppression of pro-inflammatory cytokines is not due to a direct effect the drug on immune cells, and also occurs independently of glucocorticoid receptor activation. In addition, whilst fenfluramine increases production of the anti-inflammatory cytokine interleukin-10, this cannot account for the suppression of the pro-inflammatory cytokine tumor necrosis factor-alpha induced by fenfluramine.

Cytokines and related receptor-mediated signaling pathways

Cytokines represent a multi-diverse family of polypeptide regulators; they are of relatively low molecular weight, pharmacologically active proteins that are secreted by one cell for the purpose of altering either its own functions (autocrine effect) or those of adjacent cells (paracrine effect). Cytokines are small, non-enzymatic glycoproteins whose actions are both diverse and overlapping (specificity/redundancy) and may affect diverse and overlapping target cell populations. In many instances, individual cytokines have multiple biological activities. Different cytokines can also have the same activity, which provides for functional redundancy within the inflammatory and immune systems. As biological cofactors that are released by specific cells, cytokines have specific effects on cell-cell interaction, communication, and behavior of other cells. As a result, it is infrequent that loss or neutralization of one cytokine will markedly interfere with either of these systems. The biological effect of one cytokine is often modified or augmented by another. Because an inter-digitating, redundant network of cytokines is involved in the production of most biological effects, both under physiologic and pathologic conditions, it usually requires more than a single defect in the network to alter drastically the outcome of the process. This fact therefore may have crucial significance in the development of therapeutic strategies for bio-pharmacologic intervention in cytokine-mediated inflammatory processes and infections.

Pharmaco-redox regulation of cytokine-related pathways: from receptor signaling to pharmacogenomics

Cytokines represent a multi-diverse family of polypeptide regulators; they are relatively low molecular weight (< 30 kDa), pharmacologically active proteins that are secreted by one cell for the purpose of altering either its own functions (autocrine effect) or those of adjacent cells (paracrine effect). Cytokines are small, nonenzymatic glycoproteins whose actions are both diverse and overlapping (specificity/redundancy) and may affect diverse and overlapping target cell populations. In many instances, individual cytokines have multiple biological activities. Different cytokines can also have the same activity, which provides for functional redundancy (network) within the inflammatory and immune systems. As biological cofactors that are released by specific cells, cytokines have specific effects on cell-cell interaction, communication, and behavior of other cells. As a result, it is infrequent that loss or neutralization of one cytokine will markedly interfere with either of these systems. The biological effect of one cytokine is often modified or augmented by another. Because an interdigitating, redundant network of cytokines is involved in the production of most biological effects, both under physiologic and pathologic conditions, it usually requires more than a single defect in the network to alter drastically the outcome of the process. This fact, therefore, may have crucial significance in the development of therapeutic strategies for biopharmacologic intervention in cytokine-mediated inflammatory processes and infections.