Multi-Arm PEG/Peptidomimetic Conjugate Inhibitors of DR6/APP Interaction Block Hematogenous Tumor Cell Extravasation

The binding of amyloid precursor protein (APP) expressed on tumor cells to death receptor 6 (DR6) could initiate the necroptosis pathway, which leads to necroptotic cell death of vascular endothelial cells (ECs) and results in tumor cells (TCs) extravasation and metastasis. This study reports the first inhibitor of DR6/APP interaction as a novel class of anti-hematogenous metastatic agent. By rationally utilizing three combined strategies including selection based on phage display library, d-retro-inverso modification, and multiple conjugation of screened peptidomimetic with 4-arm PEG, the polymer-peptidomimetic conjugate PEG-tAHP-DRI (tetra-(D-retro-inverso isomer of AHP-12) substitued 4-arm PEG5k ) is obtained as the most promising agent with the strongest binding potency (KD  = 51.12 × 10-9  m) and excellent pharmacokinetic properties. Importantly, PEG-tAHP-DRI provides efficient protection against TC-induced ECs necroptosis both in vitro and in vivo. Moreover, this ligand exhibits prominent anti-hematogenous metastatic activity in serval different metastatic mouse models (B16F10, 4T1, CT26, and spontaneous lung metastasis of 4T1 orthotopic tumor model) and displays no apparent detrimental effects in preliminary safety evaluation. Collectively, this study demonstrates the feasibility of exploiting DR6/APP interaction to regulate hematogenous tumor cells transendothelial migration and provides PEG-tAHP-DRI as a novel and promising inhibitor of DR6/APP interaction for developments of anti-hematogenous metastatic therapies.

Dermatological Manifestations in Pediatric Inflammatory Bowel Disease

Background and Objectives: Over the last years, inflammatory bowel disease (IBD) has been reported on a high incidence in pediatric populations and has been associated with numerous extraintestinal manifestations, making its management a real challenge for the pediatric gastroenterologist. Dermatological manifestations in IBD are either specific, related to the disease activity or treatment-associated, or non-specific. This literature review aims to identify and report the dermatological manifestations of IBD in children, the correlation between their appearance and the demographical characteristics, the relationship between these lesions and disease activity, and to highlight the impact of dermatological manifestations on an IBD treatment regime. Materials and Methods: A systemic literature review was performed, investigating articles and case reports on dermatological manifestations in children with IBD starting from 2005. A total of 159 potentially suitable articles were identified and after the exclusion process, 75 articles were selected. Results: The most common dermatological manifestations reported in pediatric IBD are erythema nodosum and pyoderma gangrenosum. More rare cases of metastatic Crohn’s disease, epidermolysis bullosa acquisita, small-vessel vasculitis, necrotizing vasculitis, leukocytoclastic vasculitis, cutaneous polyarteritis nodosa, and Sweet’s syndrome have been reported. Oral manifestations of IBD are divided into specific (tag-like lesions, mucogingivitis, lip swelling with vertical fissures, aphthous stomatitis, and pyostomatitis vegetans) and non-specific. IBD treatment may present with side effects involving the skin and mucosa. Anti-tumor necrosis factor agents have been linked to opportunistic skin infections, psoriasiform lesions, and a potentially increased risk for skin cancer. Cutaneous manifestations such as acrodermatitis enteropathica, purpuric lesions, and angular cheilitis may appear secondary to malnutrition and/or malabsorption. Conclusions: The correct diagnosis of dermatological manifestations in pediatric IBD is of paramount importance because of their impact on disease activity, treatment options, and a patient’s psychological status.

Collaborative study for the establishment of Etanercept Biological Reference Preparation Batch 1

Three preparations of the human tumour necrosis factor (TNF) receptor II Fc fusion protein (TNFR II-Fc) Etanercept were formulated and lyophilised at the National Institute for Biological Standards & Control (NIBSC) prior to evaluation in a collaborative study for their suitability to serve as a World Health Organization (WHO) International Standard (IS)/European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for the potency assay of Etanercept. Seven laboratories tested the preparations using an in vitro cell-based bioassay (TNF-α neutralisation) prescribed by the Ph. Eur. monograph on Etanercept (2895). The results of this study indicated that the candidate preparation, coded 13/204, established as the first IS for Etanercept with an assigned potency for TNF neutralisation activity of 10 000 IU per ampoule was also suitable to serve as Ph. Eur. BRP batch 1. The results were compared to those obtained with different cell-based neutralisation assays that were used by further laboratories in the context of establishing the 1st WHO IS for Etanercept. Based on these analyses, preparation 13/204 was adopted by the Ph. Eur. Commission as Etanercept BRP batch 1 with an assigned potency of 10 000 IU per ampoule.

Understanding how combinatorial targeting of TLRs and TNFR family costimulatory members promote enhanced T cell responses

INTRODUCTION

Due to the ability of pathogen-associated molecular patters and tumor necrosis factor receptor (TNFR) family costimulatory agonists to boost T cell responses, studies have combined Toll-like receptor (TLR) ligands with TNFR family costimulatory receptor agonists to induce impressive and long-lasting T cell responses. Although some studies have determined how these combinatorial vaccines promote enhanced T cell responses, much remains unknown about the mechanism used by these combinations to promote synergistic T cell responses - especially in settings of infectious diseases or cancer.

AREAS COVERED

In this review, we look in detail at the signaling pathways induced by combinatorial targeting of TLR and TNFR family costimulatory members that help them promote synergistic T cell responses. Understanding this can greatly aid the development of novel vaccine regimens that promote cellular immune responses, which is essential for treating certain infectious diseases and cancer.

EXPERT OPINION

Vaccines against some infectious diseases as well as therapeutic cancer vaccines require cellular immunity. Therefore, we evaluate here how signaling pathways induced by TLR ligand and costimulatory agonist combinations promote enhanced T cell responses during immunization with model antigens, viral pathogens, or tumor antigens. Once pathways that drive these combinatorial vaccines to boost T cell activation are identified, they can be incorporated in vaccines designed to target pathogens or cancer.

Teriparatide rapidly improves pain-like behavior in ovariectomized mice in association with the downregulation of inflammatory cytokine expression

Recent studies have indicated that teriparatide, an anti-osteoporosis agent, significantly improves back pain regardless of the presence of vertebral fracture in osteoporosis patients. The aims of this study were to examine whether teriparatide improves pain-like behavior in an ovariectomized (OVX) mouse model, and to evaluate changes in osteoclast marker levels and inflammatory cytokine expression levels induced by teriparatide treatment in bone tissue in association with improvements in pain-like behavior. OVX and sham operations were performed in 8-week-old mice, followed by teriparatide treatment for 2 weeks. Pain-like behavior tests (von Frey, paw flick and spontaneous pain test), and the measurement of serum tartrate-resistant acid phosphatase 5b (TRAP5b) level and inflammatory cytokine (interleukin [IL]-1β, IL-6 and tumor necrosis factor [TNF]-α) expression levels in the bone tissue were conducted after teriparatide treatment in OVX mice. Pain-like behavior in the von Frey test was significantly improved by teriparatide treatment in OVX mice. With regard to the early phase (within the first 7 days of treatment), teriparatide significantly improved pain-like behavior in the von Frey test, the paw flick test and the spontaneous pain test. Teriparatide significantly inhibited the expression of IL-1β, IL-6 and TNF-α in OVX mice in the early phase of the treatment, while the TRAP5b level in OVX mice was not significantly affected. We demonstrated that the teriparatide-induced rapid improvement effect on pain-like behavior in OVX mice was associated with the downregulation of inflammatory cytokine expression, including IL-1β, IL-6 and TNF-α.

Potassium Channel-blockers as Therapeutic Agents to Interfere with Bone Resorption of Periodontal Disease

Inflammatory lesions of periodontal disease contain all the cellular components, including abundant activated/memory T- and B-cells, necessary to control immunological interactive networks and to accelerate bone resorption by RANKL-dependent and -independent mechanisms. Blockade of RANKL function has been shown to ameliorate periodontal bone resorption and other osteopenic disorders without affecting inflammation. Development of therapies aimed at decreasing the expression of RANKL and pro-inflammatory cytokines by T-cells constitutes a promising strategy to ameliorate not only bone resorption, but also inflammation. Several reports have demonstrated that the potassium channels Kv1.3 and IKCa1, through the use of selective blockers, play important roles in T-cell-mediated events, including T-cell proliferation and the production of pro-inflammatory cytokines. More recently, a potassium channel-blocker for Kv1.3 has been shown to down-regulate bone resorption by decreasing the ratio of RANKL-to-OPG expression by memory-activated T-cells. In this article, we first summarize the mechanisms by which chronically activated/memory T-cells, in concert with B-cells and macrophages, trigger inflammatory bone resorption. Then, we describe the main structural and functional characteristics of potassium channels Kv1.3 and IKCa1 in some of the cells implicated in periodontal disease progression. Finally, this review elucidates some recent advances in the use of potassium channel-blockers of Kv1.3 and IKCa1 to ameliorate the clinical signs or side-effects of several immunological disorders and to decrease inflammatory bone resorption in periodontal disease. ABBREVIATIONS: AICD, activation-induced cell death; APC, antigen-presenting cells; B(K), large conductance; CRAC, calcium release-activated calcium channels; DC, dendritic cell; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; IFN-γ, interferon-γ; IP3, inositol (1,4,5)-triphosphate; (K)ir, inward rectifier; JNK, c-Jun N-terminal kinase; I(K), intermediate conductance; LPS, lipopolysaccharide; L, ligand; MCSF, macrophage colony-stimulating factor; MHC, major histocompatibility complex; NFAT, nuclear factor of activated T-cells; RANK, receptor activator of nuclear factor-κB; TCM, central memory T-cells; TEM, effector memory T-cells; TNF, tumor necrosis factor; TRAIL, TNF-related apoptosis-inducing ligand; OPG, osteoprotegerin; Omp29, 29-kDa outer membrane protein; PKC, protein kinase C; PLC, phospholipase C; RT-PCR, reverse-transcriptase polymerase chain-reaction; S(K), small conductance; TCR, T-cell receptor; and (K)v, voltage-gated.

Efficacy of Anti-TNFα in Severe and Refractory Neuro-Behcet Disease: An Observational Study

To report the safety and efficacy of anti-tumor necrosis factor α (TNFα) therapy in severe and refractory neuro-Behçet disease (NBD) patients.Observational, multicenter study including 17 BD patients (70.6% of male, with a median age of 39.3 [24-60] years), with symptomatic parenchymal NBD, refractory to previous immunosuppressant and treated with anti-TNFα (infliximab 5 mg/kg [n = 13] or adalimumab [n = 4]). Complete remission was defined by the disappearance of all neurological symptoms and by the improvement of radiological abnormalities at 12 months.Overall improvement following anti-TNF was evidenced in 16/17 (94.1%) patients including 6 (35.3%) complete response and 10 (58.8%) partial response. The median time to achieve remission was 3 months (1-6). The median Rankin score was 2 (1-4) at the initiation of anti-TNFα versus 1 (0-4) at the time of remission (P = 0.01). Corticosteroids have been stopped in 4 (23.5%) patients, and reduced by more than 50% as compared with the dosage at baseline in 10 (58.8%) patients. Side effects occurred in 23.5% of patients and required treatment discontinuation in 17% of cases.TNF blockade represents an effective therapeutic approach for patients with severe and refractory NBD, a difficult to treat population.

Recent advances in immunotherapy for kidney cancer

Immunotherapy has been a mainstay of treatment for metastatic renal cell carcinoma (mRCC) since the introduction of high-dose interleukin-2. Recently, improved knowledge of immune regulation and tumor-host immune interactions has led to the development of several novel immunotherapies. Immune checkpoint blockade showed promise in early clinical trials -- eventually leading to FDA approval of nivolumab (anti-PD-1) as a second-line treatment for mRCC. Despite encouraging results, PD-1 blockade alone does not achieve durable responses in the majority of patients treated. Improved biomarkers for patient selection, tumor vaccines and combination therapy may augment the efficacy of existing immunotherapies. This review summarizes recent progress in immunotherapy for RCC, focusing on a discussion of emerging agents.

Spondyloarthritis and inflammatory bowel disease. Comorbidity and treatment implications

Spondyloarthritides (SpA) and inflammatory bowel disease (IBD) are chronic, idiopathic inflammatory disorders of the axial and peripheral joints and the intestinal tract, respectively, affecting up to 1 % of the population. There is clinical and genetic evidence supporting some degree of overlap between the pathogenesis of these two entities. Nevertheless, their treatment is at times conflicting. NSAIDs, although useful in SpA, are considered to be possible risk factors for flares in IBD. Moreover, etanercept, a soluble TNF receptor blocker used in SpA, is ineffective in IBD. As patients with SpA often develop microscopic gut inflammation, it is important to understand the impact on disease progression or even therapeutic response. Further research is mandatory in this regard.

Anti-TNF-α therapy for patients with sepsis: a systematic meta-analysis

OBJECTIVE

In humans, the role of anti-tumour necrosis factor (TNF)-α therapy in severe sepsis and septic shock is debatable. The aim of this meta-analysis was to determine the efficacy of anti-TNF-α therapies against placebo in patients with severe sepsis or septic shock.

METHODS

A structured literature search was undertaken to identify randomised controlled trials (RCTs) conducted in patients with severe sepsis or septic shock receiving anti-TNF-α therapy or placebo. A meta-analysis on relative risk (OR) with a 95% confidence interval (95% CI) was performed.

RESULTS

Seventeen studies with a total of 8971 patients were included. When all forms of anti-TNF-α therapy were pooled together, there was a significant reduction of 28-day all-cause mortality with respect to placebo (OR = 0.91, 95% CI: 0.83-0.99; p = 0.04). Subgroup analysis showed that anti-TNF-α antibodies (monoclonal and polyclonal) reduced mortality (OR = 0.90, 95% CI: 0.81-0.99; p = 0.04). Monoclonal antibodies enhanced survival (OR = 0.91, 95% CI: 0.82-1.00; p = 0.05), while polyclonal antibodies or receptor blockers did not enhance survival (OR = 0.71, 95% CI: 0.39-1.28, p = 0.25; OR = 0.95, 95% CI: 0.78-1.17, p = 0.65). There was a trend towards better survival in patients with high levels of IL-6 (> 1000 pg/ml) and patients with shock if they were treated with anti-TNF-α therapy (OR = 0.85, 95% CI: 0.72-1.00; OR = 0.80, 95% CI: 0.62-1.04). Publication bias and statistical heterogeneity (I(2)  < 50% and p > 0.1) were absent. Sensitivity analysis suggests that these results are highly stable.

CONCLUSIONS

This meta-analysis suggests that in patients with severe sepsis (before shock), immunotherapy with anti-TNF-α monoclonal antibodies reduces overall mortality. In patients with shock or high levels of IL-6 (> 1000 pg/ml), anti-TNF-α therapy may improve survival.

National and regional dose escalation and cost of tumor necrosis factor blocker therapy in biologic-naïve rheumatoid arthritis patients in US health plans

OBJECTIVE

This study examined the proportion and magnitude of dose escalation nationally and regionally among rheumatoid arthritis (RA) patients treated with TNF-blockers and estimated the costs of TNF-blocker therapy.

METHODS

This retrospective cohort study used claims data from US commercially-insured adult RA patients who initiated adalimumab, etanercept, or infliximab therapy between 2005-2009. Biologic-naïve patients enrolled in the health plan for ≥6 months before and ≥12 months after therapy initiation were followed for 12 months. Dose escalation was assessed using three methods: (1) average weekly dose > recommended label dose, (2) average ending dispensed dose > maintenance dose, and (3) average dose after maintenance dose > maintenance dose. Annual cost of therapy included costs for mean dose and drug administration fees.

RESULTS

Overall, 1420 etanercept, 874 adalimumab, and 454 infliximab patients were included. A significantly lower proportion of etanercept-treated patients had dose escalation using the average weekly dose (3.9% vs 21.4% adalimumab and 69.6% infliximab; p < 0.0001), average ending dispensed dose (1.1% vs 10.6% adalimumab and 63.0% infliximab; p < 0.0001), and average dose after maintenance dose methods (2.8% vs 15.7% adalimumab and 69.6% infliximab; p < 0.0001). Regional dose escalation rates and magnitudes of escalation were directionally consistent with national rates. Etanercept had the lowest cost per treated RA patient ($19,690) compared to adalimumab ($23,020) and infliximab ($24,030).

LIMITATIONS

Exclusion of patients not on continuous TNF-blocker therapy limits the generalizability; however, ∼50% of patients were persistent on therapy for 12 months. The study population comprised RA patients in commercial health plans, thus the results may not be generalizable to Medicare or uninsured populations.

CONCLUSIONS

In this retrospective study, etanercept patients had the lowest proportions and magnitudes of dose escalation across all methods compared to adalimumab and infliximab patients nationally and regionally. Mean annual cost was lowest for etanercept-treated patients.

Assaying NF-κB activation and signaling from TNF receptors

Tumor necrosis factor (TNF)-mediated activation of the NF-κB family of transcription factors is mediated by two receptors, TNFR1 and TNFR2. These two receptors have unique roles in response to TNF and have been the focus of new therapeutic strategies in a variety of diseases with an immune or an inflammatory component. This chapter describes in vitro methods to functionally identify which TNF receptor is initiating NF-κB activation. This will include antibody-mediated receptor blockade and RNAi-mediated gene silencing targeting the individual receptors. The NF-κB activation methods presented include standard, accepted assays for monitoring the sequential activation steps through the NF-κB signal transduction cascade, including IκBα degradation, NF-κB nuclear translocation, and transcriptional activation of gene expression.

Mesenchymal stromal cell ciliogenesis is abrogated in response to tumor necrosis factor-α and requires NF-κB signaling

The primary cilium is a cell surface-anchored sensory organelle which expression is lost in hypoxic cancer cells and during mesenchymal stromal cells (MSC) adaptation to low oxygen levels. Since pro-inflammatory cues are among the early events which promote tumor angiogenesis, we tested the inflammatory cytokine tumor necrosis factor (TNF)-α and found that it triggered a dose-dependent loss of the primary cilia in MSC. This loss was independent of IFT88 expression, was abrogated by progranulin, an antagonist of the TNF receptor and required the NF-κB signaling intermediates IκB kinase α, β, and γ, as well as NF-κB p65. These findings strengthen the concept that the primary cilium may serve as a biomarker reflecting the tumor-supporting potential of MSC and their capacity to adapt to hypoxic and pro-inflammatory cues.

Curcumin: an orally bioavailable blocker of TNF and other pro-inflammatory biomarkers

TNFs are major mediators of inflammation and inflammation-related diseases, hence, the United States Food and Drug Administration (FDA) has approved the use of blockers of the cytokine, TNF-α, for the treatment of osteoarthritis, inflammatory bowel disease, psoriasis and ankylosis. These drugs include the chimeric TNF antibody (infliximab), humanized TNF-α antibody (Humira) and soluble TNF receptor-II (Enbrel) and are associated with a total cumulative market value of more than $20 billion a year. As well as being expensive ($15 000-20 000 per person per year), these drugs have to be injected and have enough adverse effects to be given a black label warning by the FDA. In the current report, we describe an alternative, curcumin (diferuloylmethane), a component of turmeric (Curcuma longa) that is very inexpensive, orally bioavailable and highly safe in humans, yet can block TNF-α action and production in in vitro models, in animal models and in humans. In addition, we provide evidence for curcumin's activities against all of the diseases for which TNF blockers are currently being used. Mechanisms by which curcumin inhibits the production and the cell signalling pathways activated by this cytokine are also discussed. With health-care costs and safety being major issues today, this golden spice may help provide the solution.

LINKED ARTICLES

This article is part of a themed section on Emerging Therapeutic Aspects in Oncology. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.169.issue-8.

[Effect of dexamethasone on expressions of TWEAK and Fn14 in the lung of asthmatic mice]

AIM

To investigate the effect of dexamethasone (Dex) on the expressions of TNF-like weak inducer of apoptosis (TWEAK) and fibroblast growth factor-inducible immediate-early response protein 14 (Fn14) in the lung of asthmatic mice.

METHODS

Ovalbumin (OVA) was used to induce asthma in BALB/c mice. Thirty-six female mice were randomly divided into control group (n=12), asthmatic group (n=12) and Dex treated group (n=12). The airway inflammation was evaluated by HE staining. The expressions of TWEAK and Fn14 at mRNA and protein levels were detected by RT-PCR and immunohistochemistry, respectively.

RESULTS

Both mRNA and protein levels of TWEAK and Fn14 in the asthmatic model group were significantly higher than those of control group (P<0.01), and both mRNA and protein levels of TWEAK and Fn14 in the Dex treated group were significantly lower than those of asthmatic group (P<0.01).

CONCLUSION

Dex can reduce the airway inflammation through inhibiting the expressions of TWEAK and Fn14.

Mycobacterium fortuitum infection following adalimumab treatment for psoriasis and subsequent complication-free treatment with alternate TNF-a blockers

Tumor necrosis factor-a (TNF-a) inhibitors, such as adalimumab, are often used to treat psoriasis and psoriatic arthritis. While it is well known that these agents increase the risk of reactivation tuberculosis, recent evidence suggests that the risk of other nontuberculous mycobacterial (NTM) infections is on the rise. We report cutaneous Mycobacterium fortuitum in a 60-year-old woman with psoriasis who had been receiving adalimumab therapy for psoriatic arthritis for six months. No other risk factors were identified. M. fortuitum was cultured from a lesion on the right leg. Following resolution of the lesion, the patient has been successfully treated with infliximab infusions and subsequently certalizumab without complication for the past three years. To our knowledge, this is the first report of M. fortuitum occurring in a patient receiving adalimumab with successful subsequent treatment without complication while on another TNF-a inhibitor.

Etanercept as adjunctive treatment for acute Kawasaki disease: study design and rationale

BACKGROUND

Kawasaki disease (KD) is a multisystem vasculitis affecting coronary arteries in children. Patients, refractory to standard treatment with intravenous immunoglobulin and aspirin, show higher rates of coronary artery dilation. Early tumor necrosis factor α receptor antagonism in KD may provide effective adjunctive therapy.

STUDY DESIGN

The EATAK trial is a multicenter, double-blind, randomized, and placebo-controlled trial intended to assess the efficacy of etanercept in reducing the intravenous immunoglobulin refractory rate during treatment of acute KD. Each arm will enroll 110 patients who will receive 3 doses of study drug over 2 weeks in conjunction with standard therapy. Coronary artery dilation parameters will serve as secondary end points.

DISCUSSION

The EATAK trial will test a new paradigm for treatment of acute KD involving tumor necrosis factor α antagonism by etanercept.

Clinical trial safety and mortality analyses in patients receiving etanercept across approved indications

OBJECTIVES

Assessment of associations between etanercept treatment and rare adverse events has been limited by the size of clinical trial populations. The authors examined the collective safety of etanercept in clinical trials across approved indications.

PATIENTS AND METHODS

Forty-nine U.S. and non-U.S. trials of etanercept, involving up to 13,977 patients for approved indications, with final trial reports as of May 2006, were selected from the Amgen Inc. clinical trials database. Exposure-adjusted rates of serious infections, opportunistic infections, malignancies, and deaths were reported by trial, indication, and dosage.

RESULTS

Rates of serious infections were generally similar between etanercept and controls. Overall rates of opportunistic infections and tuberculosis were low. The standardized incidence ratio (SIR) (95% CI) for malignancy was 1.00 (0.83-1.19) for all etanercept patients across all indications. The SIR for lymphoma for patients with rheumatoid arthritis was 3.45 (1.83-5.89); all other indications reported SIRs similar to those observed in the general population. The SIRs for cutaneous squamous cell carcinoma in patients with psoriasis relative to the general population with high or low sun exposure were 2.09 (1.27-3.22) and 4.96 (3.03-7.66), respectively. SIRs were less than 1.0 for all other indications regardless of sun exposure. Rates of melanoma and basal cell carcinoma were not significantly different from those in the general population. There was no increase in mortality associated with etanercept use relative to control populations.

CONCLUSION

These data support the overall tolerability of etanercept across approved indications.

[Severe asthma: new therapeutic targets]

Severe asthma is a highly incapacitating disease with no effective preventive or curative treatment. The 10% of patients with "refractory" or "difficult" asthma have chronic symptoms, episodic exacerbations and persistent airway obstruction, despite chronic? 2-agonist and steroid therapy. A major objective of current asthma research is to identify the underlying cellular and molecular mechanisms and thus to develop new treatments. Persistent airway eosinophilia is a hallmark of severe asthma. IL-5 is essential for terminal differentiation of committed eosinophil precursors and is also involved in eosinophily degranulation and priming. By releasing cytokines and cationic proteins, eosinophils contribute to airway inflammation and damage the bronchial mucosa. A monoclonal antibody against IL-5 has been shown to reduce exacerbations of refractory asthma. Interventions targeting eosinophil cationic proteins might have therapeutic potential. Structural changes in the bronchial wall, collectively known as airway remodeling, are believed to play a prominent role in the persistent airflow obstruction associated with severe asthma. In this setting the airway epithelium shows major abnormalities, including loss of barrier function, phenotypic changes, and functional disorders. The abnormal respiratory epithelium is believed to orchestrate airway remodeling through aberrant production of extracellular matrix components, fibrogenic cytokines and chemokines, and growth factors responsible for the proliferation, migration and activation of smooth muscle cells and fibroblasts. Recently, increased ET-1 synthesis by the bronchial epithelium was observed in severe refractory asthma, and was found to correlate with airway remodeling and airway obstruction. ET-1 might represent a novel therapeutic target in severe steroid-refractory asthma.

The use of tumour necrosis factor alpha-blockers in daily routine. An Austrian consensus project

To define relevant disease parameters and their respective limits indicating the initiation of TNF-alpha-blockers in individual patients. Subsequently, to analyze retrospectively patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) or ankylosing spondylitis (AS), who started TNF-alpha inhibition in 2006. Points to consider, regarded relevant for individual treatment decisions as well as their assessment methods, were ascertained by experts' consensus applying the Delphi technique. Subsequently, these parameters' thresholds with respect to the initiation of a TNF-alpha-blocker were identified. Thereafter, the rheumatologists representing 12 centres all over Austria agreed to retrospectively analyze their patients started on a TNF-alpha-blocker in 2006. Experts' opinion regarding disease parameters relevant to initiate TNF-alpha-blockers in RA patients only slightly differed from those applied in clinical trials, but the parameters' threshold values were considerably lower. For PsA patients, some differences and for AS patients, considerable differences between experts' opinion and clinical studies appeared, which held also true for decisive parameters' means and thresholds. Six hundred and fifty patients, started on TNF-blockers in 2006, could be analyzed retrospectively, 408 RA patients (53.3 years mean, 340 females), 93 PsA patients (48.9 years mean, 59 males) and 149 AS patients AS (42.2 years mean, 108 males), representing approximately 25% of all Austrian patients initiated on a TNF-blocker in this respective year. Far more individualized, patient-oriented treatment approaches, at least in part, are applied in daily routine compared with those derived from clinical trials or recommendations from investigative rheumatologists.

No regression of renal amyloid mass despite remission of nephrotic syndrome in a patient with TRAPS following etanercept therapy

Reactive systemic (AA) amyloidosis leading to renal failure is the most severe complication of tumor necrosis factor receptor-associated periodic syndrome (TRAPS). There is now growing evidence to suggest that anti-tumor necrosis factor (anti-TNF) agents may be an attractive treatment option for amyloidosis not only in TRAPS but in several forms of secondary amyloidosis complicating inflammatory rheumatic diseases. In most of the reported cases, anti-TNF agents were deemed successful on the basis of regression of proteinuria and either improvement or stabilization of creatinine clearance, while objective proof of renal amyloid regression either by serum amyloid P scintigraphy or biopsy is limited. We herein report a case of TRAPS complicated with nephrotic syndrome due to AA amyloidosis in which treatment with etanercept was associated with remission of the nephrotic syndrome but no regression of amyloid mass on the follow-up renal biopsy. Indeed, amyloid deposition was noted to be more pronounced on the second renal biopsy, particularly at tubular basement membranes. Although the variable relation between reduction in amyloid load and changes in organ function is well-known, the basis for renal recovery in association with stable or even progressive amyloid deposition is challenging. We suggest that in patients with secondary AA amyloidosis, mechanisms other than the reduction of amyloid mass could have contributed to the observed improvement of renal function with anti-TNF agents.

N-acetylcysteine inhibits TNF-alpha, sTNFR, and TGF-beta1 release by alveolar macrophages in idiopathic pulmonary fibrosis in vitro

BACKGROUND

N-acetylcysteine (NAC) can act as an antioxidant. NAC slows the rate of decline of lung function in idiopathic pulmonary fibrosis (IPF) patients concurrently treated with prednisone and azathioprine.

OBJECTIVE

In this study we investigated the effect of NAC on the production of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, IL-8, IL-10, IL-12 (p70), IL-18, transforming growth factor (TGF)-beta1, and the soluble TNF receptors (sTNFR1 and sTNFR2) by alveolar macrophages (AM) in IPF patients.

DESIGN

AMs were harvested by bronchoalveolar lavage (BAL) from 16 IPF patients and were cultured for 24 h with RPMI medium alone, or with lipopolysaccharide (LPS) (100 ng/ml), in the presence or absence of NAC at various concentrations.

RESULTS

NAC suppressed the production of TNF-alpha, its soluble receptors, and TGF-beta1 by AMs in a dose-dependent manner. At the highest concentration of NAC (10 mM), the spontaneous or LPS-stimulated production ofTNF-alpha, sTNFR1, sTNFR2, and TGF-beta1 were significantly reduced. The LPS-stimulated IL-1beta production was also suppressed by 10 mM NAC.

CONCLUSIONS

NAC has the potential to down-regulate the production of TNF-alpha and their soluble receptors, as well as TGF-beta1 and LPS-stimulated IL-1beta, by AM in IPF in vitro. NAC may have anti-inflammatory and anti-fibrotic effects.

The role of TNF superfamily members in T-cell function and diseases

Interactions that occur between several tumour necrosis factor (TNF)-TNF receptors that are expressed by T cells and various other immune and non-immune cell types are central to T-cell function. In this Review, I discuss the biology of four different ligand-receptor interactions - OX40 ligand and OX40, 4-1BB ligand and 4-1BB, CD70 and CD27, and TL1A and death receptor 3 - and their potential to be exploited for therapeutic benefit. Manipulating these interactions can be effective for treating diseases in which T cells have an important role, including inflammatory conditions, autoimmunity and cancer. Here, I explore how blocking or inducing the signalling pathways that are triggered by these different interactions can be an effective way to modulate immune responses.

Therapeutic targeting of TWEAK/Fnl4 in cancer: exploiting the intrinsic tumor cell killing capacity of the pathway

TNF-like weak inducer of apoptosis (TWEAK) and FGF-inducible molecule 14 (Fn14) are a TNF superfamily ligand-receptor pair. Initially identified as an inducer of tumor cell killing, TWEAK has pleiotropic effects, mediating proinflammatory and pro-angiogenic activity as well as stimulation of invasion, migration, and survival through its widely recognized receptor, Fn14. Fn14 is expressed at relatively low levels in normal tissues, but is dramatically elevated locally in injured and diseased tissues, where it plays a role in tissue remodeling. Herein we review the link between the TWEAK/Fn14 pathway and cancer as well as discuss potential therapeutic strategies targeting this pathway for cancer treatment. Many of the activities associated with the TWEAK/Fn14 pathway are linked with tumorigenesis and could thereby provide a growth advantage to tumors, suggesting that inhibition of the pathway may be beneficial in the treatment of cancer. At the same time, the elevated expression of Fn14 by tumor cells as well as the intrinsic tumor cell killing capacity of this receptor represents a promising alternative of harnessing the intrinsic tumor cell killing capacity of Fn14 to treat cancer.

Cooperation of the proapoptotic receptor agonist rhApo2L/TRAIL with the CD20 antibody rituximab against non-Hodgkin lymphoma xenografts

Recombinant human rhApo2L/TRAIL selectively stimulates apoptosis in various cancer cells through its receptors DR4 and DR5, and is currently in clinical trials. Preclinical studies have established antitumor activity of rhApo2L/TRAIL in models of epithelial cancers; however, efficacy in non-Hodgkin lymphoma (NHL) models is not well studied. Of 7 NHL cell lines tested in vitro, rhApo2L/TRAIL stimulated apoptosis in BJAB, Ramos RA1, and DoHH-2 cells. Rituximab, a CD20 antibody used to treat certain types of NHL, augmented rhApo2L/TRAIL-induced caspase activation in Ramos RA1 and DoHH2 but not BJAB or SC-1 cells, through modulation of intrinsic rather than extrinsic apoptosis signaling. In vivo, rhApo2L/TRAIL and rituximab cooperated to attenuate or reverse growth of tumor xenografts of all 4 of these cell lines. Depletion of natural killer (NK) cells or serum complement substantially reduced combined efficacy against Ramos RA1 tumors, suggesting involvement of antibodydependent cell- and complement-mediated cytotoxicity. Both agents exhibited greater activity against disseminated than subcutaneous BJAB xenografts, and worked together to inhibit or abolish disseminated tumors and increase survival. Moreover, rhApo2L/TRAIL helped circumvent acquired rituximab resistance of a Ramos variant. These findings provide a strong rationale for clinical investigation of rhApo2L/TRAIL in combination with rituximab as a novel strategy for NHL therapy.

Glycosylation modulates TRAIL-R1/death receptor 4 protein: different regulations of two pro-apoptotic receptors for TRAIL by tunicamycin

Death receptor 4 (DR4) is a receptor of the antitumor death ligand, TNF-related apoptosis-inducing ligand (TRAIL), and is considered a promising molecular target for cancer therapy. Here, we show a novel regulation of DR4 protein. Tunicamycin treatment, which is an inducer of endoplasmic reticulum (ER)-stress, generated a lower molecular-weight pattern of DR4, but not DR5 protein in prostate cancer DU145 and PC3 cells. Thus, we termed the small form of DR4 protein, DR4-Small (DR4-S) and the large form, DR4-Large (DR4-L). Using DR4 siRNA, we confirmed that DR4-S also stands for DR4 protein. Other ER-stress inducers, brefeldin A and thapsigargin did not generate DR4-S. On the other hand, these ER-stress inducers increased DR5 protein. Tunicamycin induces ER-stress following the inhibition of N-linked glycosylation. Thus, we examined DR4 protein in cell lysates treated with glycosydase. Glycosydase treatments generated DR4-S protein, similar to tunicamycin. These results indicate that tunicamycin regulates DR4 protein size via inhibition of glycosylation.

Patient profiles in psoriatic disease: a case-based approach

Psoriasis and psoriatic arthritis are related conditions that can have numerous untoward consequences. Moreover, appropriate management of these conditions can be challenging, as each affected patient has unique needs that must be addressed. With that in mind, the authors discuss three real-life cases, highlighting principles that may facilitate the effective case-by-case management of psoriatic disease.

Functions of TNF and its receptors in renal disease: distinct roles in inflammatory tissue injury and immune regulation

Tumor necrosis factor (TNF) alpha is a potent proinflammatory cytokine and important mediator of inflammatory tissue damage. In addition, it has important immune-regulatory functions. Many experimental studies and clinical observations support a role for TNF in the pathogenesis of acute and chronic renal disease. However, given its dual functions in inflammation and immune regulation, TNF may mediate both proinflammatory as well as immunosuppressive effects, particularly in chronic kidney diseases and systemic autoimmunity. Blockade of TNF in human rheumatoid arthritis or Crohn's disease led to the development of autoantibodies, lupus-like syndrome, and glomerulonephritis in some patients. These data raise concern about using TNF-blocking therapies in renal disease because the kidney may be especially vulnerable to the manifestation of autoimmune processes. Interestingly, recent experimental evidence suggests distinct roles for the 2 TNF receptors in mediating local inflammatory injury in the kidney and systemic immune-regulatory functions. In this review the biologic properties of TNF and its receptors, TNF receptors 1 and 2, relevant to kidney disease are summarized followed by a review of the available experimental and clinical data on the pathogenic role of the TNF system in nonimmune and immune renal diseases. Experimental evidence also is reviewed that supports a rationale for specifically blocking TNF receptor 2 versus anti-TNF therapies in some nephropathies, including immune complex-mediated glomerulonephritis.

[Etanercept: recombinant human soluble tumor necrosis factor receptor fusion protein]

TNF is a central cytokine in the pathogenesis of rheumatoid arthritis(RA), which induces synovitis as well as joint damage. Etanercept is a recombinant human soluble TNF receptor that binds specifically to TNF receptor, and inhibits TNF receptor-mediated signaling cascade. Recent investigations have revealed successful clinical efficacy of biologics in RA including etanercept. We reviewed here the structure and efficacy of etanercept in RA according to the published evidence.

Blockade of the interleukin-21/interleukin-21 receptor pathway ameliorates disease in animal models of rheumatoid arthritis

OBJECTIVE

Interleukin-21 (IL-21) is a T cell-derived cytokine that modulates T cell, B cell, and natural killer cell responses. In this study, the effects of blocking IL-21 were examined in 2 rodent models of rheumatoid arthritis (RA) to determine whether IL-21 contributes to their pathologic processes.

METHODS

DBA/1 mice were immunized with bovine type II collagen and then treated with murine IL-21 receptor Fc fusion protein (IL-21R.Fc), which was initiated after the onset of arthritis symptoms in 10% of the cohort. The mice were assessed 3 times per week for signs of disease, including histologic features as well as serum cytokine, Ig, and cytokine messenger RNA (mRNA) levels in the paws. In a separate experiment, Lewis rats were immunized with Freund's complete adjuvant followed by administration of IL-21R.Fc at the peak of inflammation in the joints. Rats were assessed daily for histologic features and for scoring of arthritis severity. In addition, the effects of IL-21R.Fc on the production of interferon-gamma (IFNgamma) by T cells were examined.

RESULTS

Treatment of DBA/1 mice with IL-21R.Fc reduced the clinical and histologic signs of collagen-induced arthritis. Nonspecific IgG1 levels were decreased in response to treatment. The levels of IL-6 mRNA in the paws and the serum IL-6 levels were decreased after treatment with IL-21R.Fc. IFNgamma mRNA levels were increased in the paws, and the addition of IL-21R.Fc to collagen-activated lymph node cultures enhanced the levels of IFNgamma. Collagen-specific spleen cell responses in IL-21R.Fc-treated mice were observed as reduced levels of IFNgamma and increased levels of IL-6. Treatment of Lewis rats with IL-21R.Fc after induction of adjuvant-induced arthritis resulted in reversal of disease signs and improvements in histologic parameters.

CONCLUSION

These findings demonstrate a pathogenic role for IL-21 in animal models of RA, and support consideration of IL-21 as a therapeutic target in human RA.

GITR ligation blocks allograft protection by induced CD25+CD4+ regulatory T cells without enhancing effector T-cell function

The induction of operational tolerance prior to transplant could provide a solution to the complications of current immunosuppression in transplantation. In rodents, operational tolerance frequently correlates with the presence of CD25(+)CD4(+) regulatory T cells (Tregs) but their function is usually demonstrated by adoptive transfer into lymphopenic hosts leading some to question their relevance to normal immunocompetent recipients. The role of these cells in primary transplant recipients has been explored using anti-CD25 antibody but specific targeting of Treg is not possible since CD25 is also up-regulated on activated effector T cells. To overcome this limitation we targeted the Treg associated molecule GITR in tolerized primary transplant recipients. This reverses regulation resulting in acute allograft rejection. This is not due to co-stimulation of effector cells since rejection mediated by isolated populations of CD4(+)CD25(-) or CD8(+)CD25(-) T cells transferred into Rag(-/-) mice was not enhanced by anti-GITR antibody. Furthermore, GITR cross-linking does not provide co-stimulation for in vitro proliferation of the same CD4(+)CD25(-) or CD8(+)CD25(-) T-cell populations in response donor-strain APC. Thus, CD4(+)CD25(+)GITR(+) Treg play an essential role in early graft protection in primary transplant recipients following tolerance induction providing further support for protocols that might generate similar populations in clinical transplantation.

Novel opportunities for therapeutic targeting in systemic autoimmune diseases

Systemic autoimmune diseases, such as systemic lupus erythematosus and rheumatoid arthritis, continue to cause significant morbidity in affected persons. In the past few years, significant progress was made in understanding their pathogenesis and the underlying molecular mechanisms. As a result, a number of new exciting therapeutic options have become available, and novel therapeutic targets have emerged, including B-cell depletion therapies, B cell-activating factor of tumor necrosis factor family (BAFF) antagonists, and FcgammaRIIB receptor antagonists. Also promising is the current interest centered on the development of inhibition of signal transduction pathways, such as pharmacological inhibitors that act at various levels of signal transduction pathways.

Flare and change of psoriasis morphology during the course of treatment with tumour necrosis factor blockers

Tumour necrosis factor (TNF) blockers represent an exciting advance in the management of psoriasis. However, the safety profile of these drugs is not completely established. We present a review of the literature, and report on eight patients: two with the unexpected appearance of psoriasis, and the remaining six with exacerbation and change in morphology of their existing psoriasis, all of which occurred during treatment with the TNF blockers adalimumab, etanercept and infliximab. The two new cases, neither of whom had any personal or family history of psoriasis, developed pustular psoriasis on the palms and/or soles. The other six patients, previously diagnosed with severe chronic plaque psoriasis (four patients), generalized pustular psoriasis (one) and erythrodermic psoriasis (one), developed eruptive guttate psoriasis between 15 days and 18 months after the beginning of therapy. These patients had never before presented guttate-type psoriatic lesions, and the lesions appeared in areas of the body that were free of psoriatic plaques at baseline.

Chronic ethanol exposure inhibits distraction osteogenesis in a mouse model: role of the TNF signaling axis

Tumor necrosis factor-alpha (TNF-alpha) is an inflammatory cytokine that modulates osteoblastogenesis. In addition, the demonstrated inhibitory effects of chronic ethanol exposure on direct bone formation in rats are hypothetically mediated by TNF-alpha signaling. The effects in mice are unreported. Therefore, we hypothesized that in mice (1) administration of a soluble TNF receptor 1 derivative (sTNF-R1) would protect direct bone formation during chronic ethanol exposure, and (2) administration of recombinant mouse TNF-alpha (rmTNF-alpha) to ethanol naïve mice would inhibit direct bone formation. We utilized a unique model of limb lengthening (distraction osteogenesis, DO) combined with liquid diets to measure chronic ethanol's effects on direct bone formation. Chronic ethanol exposure resulted in increased marrow TNF, IL-1, and CYP 2E1 RNA levels in ethanol-treated vs. control mice, while no significant weight differences were noted. Systemic administration of sTNF-R1 during DO (8.0 mg/kg/2 days) to chronic ethanol-exposed mice resulted in enhanced direct bone formation as measured radiologically and histologically. Systemic rmTNF-alpha (10 microg/kg/day) administration decreased direct bone formation measures, while no significant weight differences were noted. We conclude that chronic ethanol-associated inhibition of direct bone formation is mediated to a significant extent by the TNF signaling axis in a mouse model.

Costimulatory molecules as targets for the induction of transplantation tolerance

Transplantation is the only cure for end-stage organ failure. Transplanted tissues are usually recognized by the immune system as foreign and are rapidly rejected in the absence of immunosuppression. Transplanted organs between genetically distinct individuals are termed allografts and their acute rejection is orchestrated by the activation of allospecific T cells. To prevent acute allograft rejection, current therapies suppress all T cells irrespective of their specificities and must be taken life-long, leaving patients with decreased defenses against infectious agents and cancers. The goal in transplantation research is to develop therapies with the capacity to induce graft-specific tolerance. Ideal therapies should be of short duration and target only alloreactive T cells, leaving other T cells competent to fight infections and cancers. Researchers have studied the mechanisms of activation/regulation of T cells in the hopes that manipulation of these pathways may facilitate the induction of tolerance. Activation of T cells requires recognition by the T cell receptor (TCR) of antigenic peptides presented within major histocompatibility complexes (MHC) on the surface of antigen-presenting cells (APCs). In addition, concurrent engagement of costimulatory receptors on T cells by ligands on APCs is also required for optimal T cell responses, such that the ultimate outcome of TCR engagement reflects the relative sum of multiple positive and negative costimulatory signals. Targeting costimulatory receptor/ligand pairs has been used effectively to induce allograft tolerance in specific rodent transplantation models. This strategy has however been less effective in larger mammals. In this review, we will summarize the different reagents used to target costimulatory molecules, their effects, and the possible reasons limiting their efficacy in higher order mammals.

Inflammation of choriodecidua induces tumor necrosis factor alpha-mediated apoptosis of human myometrial cells

The present study investigated the ability of human choriodecidua to induce myometrial cell apoptosis through the secretion of tumor necrosis factor alpha (TNF). The secretion of TNF was evaluated in the culture supernatants of amnion and choriodecidua explants that were exposed to the bacterial endotoxin lipopolysaccharide (LPS) to mimic inflammation. The choriodecidua explants produced more TNF than the amnion explants in response to LPS stimulation, despite the fact that the choriodecidua had lower levels of TLR4 expression. Moreover, conditioned medium obtained from LPS-treated choriodecidua explants, but not that from amnion explants, decreased the number of viable cultured myometrial cells and induced cell apoptosis by inducing the overexpression of the proapoptotic protein BAX and by decreasing the expression of the anti-apoptotic protein BCL2. Neutralization of TNF in the choriodecidua-conditioned medium reversed this effect. Exogenous TNF mimicked LPS-treated choriodecidua-conditioned medium in that it induced myometrial cell apoptosis, reduced BCL2 expression, and increased BAX expression. Using neutralizing antibodies against both subtypes of TNF receptors, we found that only TNFRSF1A participates in TNF-induced myometrial cell apoptosis. Our in vitro model of LPS-induced inflammation of human fetal membrane explants suggests a mechanism by which TNF secreted by choriodecidua governs human myometrial cell apoptosis at the end of pregnancy. These data support the hypothesis that TNF participates in the complex network of signaling processes associated with uterine involution.

Investigational anti-inflammatory agents for the treatment of ischaemic brain injury

Stroke is the third leading cause of death and the leading cause of disability in Western countries. To date, only approximately 2% of stroke patients are eligible for thrombolysis treatment with recombinant tissue plasminogen activator. The very limited options available for stroke treatment and recent disappointing clinical trials in stroke call for novel therapeutic approaches. Inflammation represents one of the key pathophysiological mechanisms for the progression of ischaemic stroke. Recent advances in preclinical models of stroke using investigational small molecular antagonists, neutralising antibodies/proteins or genetically altered gene functions against various inflammatory mediators suggest a great therapeutic potential of anti-inflammation for ischaemic stroke. The scope of the present review is to update the evidence for a role of inflammatory pathways in stroke and to summarise the investigational drugs currently available both in preclinical and clinical development for potential treatment of ischaemic stroke.

Balancing co-stimulation and inhibition with BTLA and HVEM

The interaction between B- and T-lymphocyte attenuator (BTLA), an inhibitory receptor whose extracellular domain belongs to the immunoglobulin superfamily, and herpesvirus-entry mediator (HVEM), a co-stimulatory tumour-necrosis factor receptor, is unique in that it is the only receptor-ligand interaction that directly bridges these two families of receptors. This interaction has raised many questions about how receptors from two different families could interact and what downstream signalling events might occur as a result of receptor ligation. As we discuss, recent studies show that engagement of HVEM with its endogenous ligand (LIGHT) from the tumour-necrosis factor family induces a powerful immune response, whereas HVEM interactions with BTLA negatively regulate T-cell responses.

Inhibition of TNF receptor 1 internalization by adenovirus 14.7K as a novel immune escape mechanism

The adenoviral protein E3-14.7K (14.7K) is an inhibitor of TNF-induced apoptosis, but the molecular mechanism underlying this protective effect has not yet been explained exhaustively. TNF-mediated apoptosis is initiated by ligand-induced recruitment of TNF receptor-associated death domain (TRADD), Fas-associated death domain (FADD), and caspase-8 to the death domain of TNF receptor 1 (TNFR1), thereby establishing the death-inducing signaling complex (DISC). Here we report that adenovirus 14.7K protein inhibits ligand-induced TNFR1 internalization. Analysis of purified magnetically labeled TNFR1 complexes from murine and human cells stably transduced with 14.7K revealed that prevention of TNFR1 internalization resulted in inhibition of DISC formation. In contrast, 14.7K did not affect TNF-induced NF-kappaB activation via recruitment of receptor-interacting protein 1 (RIP-1) and TNF receptor-associated factor 2 (TRAF-2). Inhibition of endocytosis by 14.7K was effected by failure of coordinated temporal and spatial assembly of essential components of the endocytic machinery such as Rab5 and dynamin 2 at the site of the activated TNFR1. Furthermore, we found that the same TNF defense mechanisms were instrumental in protecting wild-type adenovirus-infected human cells expressing 14.7K. This study describes a new molecular mechanism implemented by a virus to escape immunosurveillance by selectively targeting TNFR1 endocytosis to prevent TNF-induced DISC formation.

The role of TNF-alpha and its receptors in the production of NGF and GDNF by astrocytes

The neurotrophic factors, nerve growth factor (NGF) and glial cell line-derived neurotrophic factor (GDNF), are produced by astrocytes, and are induced by inflammatory stimuli including bacterial lipopolysaccharide and pro-inflammatory cytokines. In this study, we examined the regulatory mechanisms of tumor necrosis factor-alpha (TNF-alpha)-induced production of neurotrophic factors. We show here that cultured astrocytes express both TNF-alpha receptor 1 (TNFR1) and TNFR2, and that activation of these receptors by TNF-alpha promotes expression of both NGF and GDNF. In addition, we observe that not only exogenous TNF-alpha but also TNF-alpha produced by astrocytes induce NGF and GDNF production in astrocytes. These results suggest that an autocrine loop involving TNF-alpha contributes to the production of neurotrophic factors in response to inflammation.

Molecules involved in T-B co-stimulation and B cell homeostasis: possible targets for an immunological intervention in autoimmunity

The deepened knowledge of co-stimulatory mechanisms within the immunological synapse and the emerging biological principles governing B cell homeostasis provide a plethora of new possibilities to selectively block or enhance immune responses. These mechanisms are highly relevant to the development of new treatment modalities for autoimmune diseases. Here we review approaches to antagonise members of the CD28-B7 superfamily as well as the TNF receptor ligand superfamily members, BAFF and APRIL, and their corresponding receptors on B cells (BAFF-R, TACI and BCMA). The proof of principle that such manipulations have indeed profound consequences for the human immune response comes from genetically manipulated mouse models, and, more importantly, from human immunodeficiency syndromes. Thus, the recent discovery of deletions in the ICOS, BAFF-R and TACI genes leading to disturbances in late B cell differentiation and hypogammaglobulinaemia underline the potential impact of targeting these molecules for therapeutic strategies in autoimmune disorders.

Relapsing oligoarticular septic arthritis during etanercept treatment of rheumatoid arthritis

Septic arthritis is a commonly reported complication of rheumatoid arthritis (RA). Tumor necrosis factor alpha (TNF-alpha) plays an important role in host defense against infection. Inhibition of its activity could therefore be anticipated to augment the risk of infection. Both opportunistic and bacterial infections have been described in patients with RA treated with anti-TNF-alpha therapy. We describe a patient who experienced 2 episodes of septic arthritis. Both occurred while the patient was on etanercept. Recurrence developed despite prolonged parenteral antibiotic. To our knowledge, this is the first report of relapsing oligoarticular methicillin-sensitive Staphylococcus aureus septic arthritis despite prolonged antibiotic treatment in a patient receiving etanercept therapy. Our case underscores the advisability of discontinuing TNF-alpha blockade in patients with septic arthritis during prolonged antimicrobial therapy.

Mcl-1L cleavage is involved in TRAIL-R1– and TRAIL-R2–mediated apoptosis induced by HGS-ETR1 and HGS-ETR2 human mAbs in myeloma cells

We evaluated the ability of 2 human mAbs directed against TRAILR1 (HGS-ETR1) and TRAILR2 (HGS-ETR2) to kill human myeloma cells. HGS-ETR1 and HGS-ETR2 mAbs killed 15 and 9 human myeloma cell lines (HMCLs; n = 22), respectively. IL-6, the major survival and growth factor for these HMCLs, did not prevent their killing. Killing induced by either HGS-ETR1 or HGS-ETR2 was correlated with the cleavage of Mcl-1L, a major molecule for myeloma survival. Mcl-1L cleavage and anti-TRAILR HMCL killing were dependent on caspase activation. Kinetic studies showed that Mcl-1L cleavage occurred very early (less than 1 hour) and became drastic once caspase 3 was activated. Our data showed that both the extrinsic (caspase 8, Bid) and the intrinsic (caspase 9) pathways are activated by anti–TRAIL mAb. Finally, we showed that the HGS-ETR1 and, to a lesser extent, the HGS-ETR2 mAbs were able to induce the killing of primary myeloma cells. Of note, HGS-ETR1 mAb was able to induce the death of medullary and extramedullary myeloma cells collected from patients at relapse. Taken together, our data clearly encourage clinical trials of anti–TRAILR1 mAb in multiple myeloma, especially for patients whose disease is in relapse, at the time of drug resistance.

IL-18 bridges innate and adaptive immunity through IFN-gamma and the CD134 pathway

IL-18 induces inflammation resulting in either enhanced protection from pathogens or exacerbation of autoimmunity, and T cells are profoundly activated during these responses. How IL-18 influences T cell activation is unknown, but this study in mice shows that IL-18 boosted Ag-specific T cell clonal expansion of effector T cells and induced a subpopulation of IFN-gamma superproducing T cells. Commitment to IFN-gamma production through IL-18 was independent of NK cells and IL-12 but dependent on host-derived IFN-gamma. To determine how expansion of these effectors occurred, IL-18 was shown to induce OX40L on dendritic cells, whereas peptide stimulation induced CD134 (OX40) on specific T cells. CD134 blockade inhibited T cell effector expansion thereby reducing the number of IFN-gamma superproducers by 12-fold. Thus, independent of IL-12, IL-18 impacts T cell immunity throughout lymphoid and nonlymphoid tissue by bridging the innate and adaptive arms of the immune system through IFN-gamma and the CD134 costimulatory pathway.

Proinflammatory role of glucocorticoid-induced TNF receptor-related gene in acute lung inflammation

Glucocorticoid-induced TNFR-related gene (GITR) participates in the immune/inflammatory response. Because GITR expression has been described in cells other than T lymphocytes, we investigated whether it also modulates acute inflammatory response. Using GITR-deficient (GITR(-/-)) mice, we analyzed the role of GITR in the development of carrageenan-induced lung inflammation (pleurisy) by studying several proinflammatory markers 2-8 h after carrageenan injection. When compared with GITR(+/+), GITR(-/-) mice exhibited decreased production of turbid exudate containing a lower number of leukocytes. This was correlated with the reduction of inflammatory markers (including TNF-alpha, IL-1beta, myeloperoxidase, inducible NO synthase, and cyclooxygenase 2) in the pleural exudate and/or in the lung. Moreover, endothelial cells expressed lower levels of adhesion molecules. In lungs of GITR(+/+) mice, GITR ligand expression was not modulated during pleurisy, while that of GITR increased, as a consequence of increased infiltration by GITR-expressing cells and of GITR up-regulation in macrophages and endothelial cells. Finally, cotreatment of GITR(+/+) mice with carrageenan and Fc-GITR fusion protein decreased the number of inflammatory cells (pleural macrophages and lung neutrophils) as compared with carrageenan treatment alone, confirming that GITR plays a role in the modulation of pleurisy.

15-Deoxy-Δ12,14-prostaglandin J2 induces death receptor 5 expression through mRNA stabilization independently of PPARγ and potentiates TRAIL-induced apoptosis

15-Deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), the terminal derivative of the PGJ series, is emerging as a potent antineoplastic agent among cyclopentenone prostaglandins derivatives and also known as the endogenous ligand of peroxisome proliferator-activated receptor gamma (PPARgamma). On the other hand, death receptor 5 (DR5) is a specific receptor for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), which is one of the most promising candidates for new cancer therapeutics. Here, we report that 15d-PGJ(2) induces DR5 expression at both mRNA and protein levels, resulting in the synergistic sensitization of TRAIL-induced apoptosis in human neoplastic cells, such as Jurkat human leukemia cells or PC3 human prostate cancer cells. 15d-PGJ(2) significantly increased DR5 mRNA stability, whereas it did not activate DR5 promoter activity. Synthetic PPARgamma agonists, such as pioglitazone or rosiglitazone, did not mimic the DR5-inducing effects of 15d-PGJ(2), and a potent PPARgamma inhibitor GW9662 failed to block DR5 induction by 15d-PGJ(2), suggesting PPARgamma-independent mechanisms. Cotreatment with 15d-PGJ(2) and TRAIL enhanced the sequential activation of caspase-8, caspase-10, caspase-9, caspase-3, and Bid. DR5/Fc chimera protein, zVAD-fmk pancaspase inhibitor, and caspase-8 inhibitor efficiently blocked the activation of these apoptotic signal mediators and the induction of apoptotic cell death enhanced by cotreatment with 15d-PGJ(2) and TRAIL. Moreover, a double-stranded small interfering RNA targeting DR5 gene, which suppressed DR5 up-regulation by 15d-PGJ(2), significantly attenuated apoptosis induced by cotreatment with 15d-PGJ(2) and TRAIL. These results suggest that 15d-PGJ(2) is a potent sensitizer of TRAIL-mediated cancer therapeutics through DR5 up-regulation.

A novel BLyS antagonist peptide designed based on the 3-D complex structure of BCMA and BLyS

B lymphocyte stimulator (BLyS) is a member of tumor necrosis factor (TNF) family. Because of its roles in autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and Sjogren syndrome (SS), BLyS antagonists have been tested to treat SLE- and RA-like symptoms in mice and obtained optimistic results. So far, reported BLyS antagonists were mostly decoyed BLyS receptors or anti-BLyS antibodies. In this study, a novel BLyS antagonist peptide, PT, was designed based on the modeling 3-D complex structure of BCMA and BLyS. The interaction mode of PT with BLyS was analyzed theoretically. The results of competitive ELISA demonstrated that PT could inhibit the binding of BCMA-Fc and anti-BLyS antibody to BLyS in vitro. In addition, PT could partly block the proliferating activity of BLyS on mice splenocytes. The BLyS antagonizing activity of PT was significant (p<0.05). This study highlights the possibility of using BLyS antagonist peptide to neutralize BLyS activity. Further optimization of PT with computer-guided molecular design method to enhance its biopotency may be useful in developing new BLyS antagonists to treat BLyS-related autoimmune diseases.