Inflammasome and cytokine blocking strategies in autoinflammatory disorders

Phytochemical mediated modulation of COX-3 and NFκB for the management and treatment of arthritis

In this study, we investigated whether zerumbone (ZBN), ellagic acid (ELA) and quercetin (QCT), the plant-derived components, can modulate the role of COX-3 or cytokines liable in arthritic disorder. Initially, the effect of ZBN, ELA, and QCT on inflammatory process was investigated using in-vitro models. In-silico docking and molecular dynamics study of these molecules with respective targets also corroborate with in-vitro studies. Further, the in-vivo anti-arthritic potential of these molecules in Complete Freund's adjuvant (CFA)-induced arthritic rats was confirmed. CFA increases in TNF-α and IL-1β levels in the arthritic control animals were significantly (***p < 0.001) attenuated in the ZBN- and ELA-treated animals. CFA-induced attenuation in IL-10 levels recovered under treatment. Moreover, ELA attenuated CFA-induced upregulation of COX-3 and ZBN downregulated CFA-triggered NFκB expression in arthritic animals. The bonding patterns of zerumbone in the catalytic sites of targets provide a useful hint in designing and developing suitable derivatives that can be used as a potential drug. To our best knowledge, the first time we are reporting the role of COX-3 in the treatment of arthritic disorders which could provide a novel therapeutic approach for the treatment of inflammatory disorders.

Targeting Inflammation in Non-Small Cell Lung Cancer through Drug Repurposing

Lung cancer is the most common cause of cancer-related deaths. Lung cancers can be classified as small-cell (SCLC) or non-small cell (NSCLC). About 84% of all lung cancers are NSCLC and about 16% are SCLC. For the past few years, there have been a lot of new advances in the management of NSCLC in terms of screening, diagnosis and treatment. Unfortunately, most of the NSCLCs are resistant to current treatments and eventually progress to advanced stages. In this perspective, we discuss some of the drugs that can be repurposed to specifically target the inflammatory pathway of NSCLC utilizing its well-defined inflammatory tumor microenvironment. Continuous inflammatory conditions are responsible to induce DNA damage and enhance cell division rate in lung tissues. There are existing anti-inflammatory drugs which were found suitable for repurposing in non-small cell lung carcinoma (NSCLC) treatment and drug modification for delivery via inhalation. Repurposing anti-inflammatory drugs and their delivery through the airway is a promising strategy to treat NSCLC. In this review, suitable drug candidates that can be repurposed to treat inflammation-mediated NSCLC will be comprehensively discussed together with their administration via inhalation from physico-chemical and nanocarrier perspectives.

Physiologic roles of P2 receptors in leukocytes

Since their discovery in the 1970s, purinergic receptors have been shown to play key roles in a wide variety of biologic systems and cell types. In the immune system, purinergic receptors participate in innate immunity and in the modulation of the adaptive immune response. In particular, P2 receptors, which respond to extracellular nucleotides, are widely expressed on leukocytes, causing the release of cytokines and chemokines and the formation of inflammatory mediators, and inducing phagocytosis, degranulation, and cell death. The activity of these receptors is regulated by ectonucleotidases-expressed in these same cell types-which regulate the availability of nucleotides in the extracellular environment. In this article, we review the characteristics of the main purinergic receptor subtypes present in the immune system, focusing on the P2 family. In addition, we describe the physiologic roles of the P2 receptors already identified in leukocytes and how they can positively or negatively modulate the development of infectious diseases, inflammation, and pain.

The evolving story of apolipoprotein L1 nephropathy: the end of the beginning

Genetic coding variants in APOL1, which encodes apolipoprotein L1 (APOL1), were identified in 2010 and are relatively common among individuals of sub-Saharan African ancestry. Approximately 13% of African Americans carry two APOL1 risk alleles. These variants, termed G1 and G2, are a frequent cause of kidney disease — termed APOL1 nephropathy — that typically manifests as focal segmental glomerulosclerosis and the clinical syndrome of hypertension and arterionephrosclerosis. Cell culture studies suggest that APOL1 variants cause cell dysfunction through several processes, including alterations in cation channel activity, inflammasome activation, increased endoplasmic reticulum stress, activation of protein kinase R, mitochondrial dysfunction and disruption of APOL1 ubiquitinylation. Risk of APOL1 nephropathy is mostly confined to individuals with two APOL1 risk variants. However, only a minority of individuals with two APOL1 risk alleles develop kidney disease, suggesting the need for a ‘second hit’. The best recognized factor responsible for this ‘second hit’ is a chronic viral infection, particularly HIV-1, resulting in interferon-mediated activation of the APOL1 promoter, although most individuals with APOL1 nephropathy do not have an obvious cofactor. Current therapies for APOL1 nephropathies are not adequate to halt progression of chronic kidney disease, and new targeted molecular therapies are in clinical trials.

This Review summarizes current understanding of the role of APOL1 variants in kidney disease. The authors discuss the genetics, protein structure and biological functions of APOL1 variants and provide an overview of promising therapeutic strategies.

In contrast to other APOL family members, which are primarily intracellular, APOL1 contains a unique secretory signal peptide, resulting in its secretion into plasma.

APOL1 renal risk alleles provide protection from African human trypanosomiasis but are a risk factor for progressive kidney disease in those carrying two risk alleles.

APOL1 risk allele frequency is ~35% in the African American population in the United States, with ~13% of individuals having two risk alleles; the highest allele frequencies are found in West African populations and their descendants.

Cell and mouse models implicate endolysosomal and mitochondrial dysfunction, altered ion channel activity, altered autophagy, and activation of protein kinase R in the pathogenesis of APOL1-associated kidney disease; however, the relevance of these injury pathways to human disease has not been resolved.

APOL1 kidney disease tends to be progressive, and current standard therapies are generally ineffective; targeted therapeutic strategies hold the most promise.

Luxeptinib disables NLRP3 inflammasome-mediated IL-1β release and pathways required for secretion of inflammatory cytokines IL-6 and TNFα

Luxeptinib (CG-806) is an orally bioavailable multikinase inhibitor with nanomolar potency against select clusters of kinases including the BTK, FLT3, TRK, STE/MAPK and aurora kinase clusters. It is cytotoxic to primary malignant cells obtained from patients with AML, ALL, and CLL at lower concentrations than other BTK and FLT3 inhibitors, and has activity in AML and lymphoma xenografts at concentrations attainable in patients. Exposure of macrophages and monocytes to endotoxin triggers the release of IL-1β through activation of the NLRP3 inflammasome and IL-6 and TNFα through transcriptional up-regulation. These cytokines are key components of the innate immune signaling network that plays a central role in the pathogenesis of multiple human diseases including cancer. Drugs that concurrently inhibit proliferation and inflammatory signaling pathways may provide better therapeutic efficacy. The aim of this study was to determine the extent to which luxeptinib interferes with the release of IL-1β, IL-6 and TNFα from THP-1 monocytes and bone marrow-derived macrophages following endotoxin exposure and priming of the NLRP3 inflammasome. Luxeptinib inhibited the release of all 3 cytokines from THP-1 monocytes and macrophages at concentrations of 0.1 µM and above. Investigation of the mechanism disclosed that luxeptinib does not inhibit the assembly of the NLRP3 inflammasome but disables its ability to cleave and activate caspase-1 that is required for IL-1β release. It also inhibits the kinases p38MAPK, ERK1/2, SAPK/JNK and activation of transcription factor NF-κBp65 with a concentration profile similar to its inhibition of cytokine release. IMPLICATIONS: The ability of luxeptinib to inhibit the NLRP3-mediated release of IL-1β and pathways involved in the release of IL-6 and TNFα at concentrations which are well-tolerated in patients makes it a candidate for the treatment of inflammatory diseases and inflammation-associated resistance in cancer.

Identification of an ASC oligomerization inhibitor for the treatment of inflammatory diseases

The ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain (CARD)) protein is an scaffold component of different inflammasomes, intracellular multiprotein platforms of the innate immune system that are activated in response to pathogens or intracellular damage. The formation of ASC specks, initiated by different inflammasome receptors, promotes the recruitment and activation of procaspase-1, thereby triggering pyroptotic inflammatory cell death and pro-inflammatory cytokine release. Here we describe MM01 as the first-in-class small-molecule inhibitor of ASC that interferes with ASC speck formation. MM01 inhibition of ASC oligomerization prevents activation of procaspase-1 in vitro and inhibits the activation of different ASC-dependent inflammasomes in cell lines and primary cultures. Furthermore, MM01 inhibits inflammation in vivo in a mouse model of inflammasome-induced peritonitis. Overall, we highlight MM01 as a novel broad-spectrum inflammasome inhibitor for the potential treatment of multifactorial diseases involving the dysregulation of multiple inflammasomes.

Anti-TNF treatment corrects IFN-γ-dependent proinflammatory signatures in Blau syndrome patient-derived macrophages

BACKGROUND

Blau syndrome (BS) is an autoinflammatory disease associated with mutations in nucleotide-binding oligomerization domain 2. Although treatments with anti-TNF agents have been reported to be effective, the underlying molecular mechanisms remain unclear.

OBJECTIVE

We aimed to elucidate the mechanisms of autoinflammation in patients with BS and to clarify how anti-TNF treatment controls the disease phenotype at the cellular level in clinical samples.

METHODS

Macrophages were differentiated from monocytes of 7 BS patients, and global transcriptional profiles of 5 patients were analyzed with or without IFN-γ stimulation. Macrophages were also generated from BS-specific induced pluripotent stem cells (iPSCs), and their transcriptome was examined for comparison.

RESULTS

Aberrant inflammatory responses were observed upon IFN-γ stimulation in macrophages from untreated BS patients, but not in those from patients treated with anti-TNF. iPSC-derived macrophages carrying a disease-associated mutation also showed IFN-γ-dependent accelerated inflammatory responses. Comparisons of peripheral blood- and iPSC-derived macrophages revealed the upregulation of nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB) targets in unstimulated macrophages as a common feature.

CONCLUSIONS

IFN-γ stimulation is one of the key signals driving aberrant inflammatory responses in BS-associated macrophages. However, long-term treatment with anti-TNF agents ameliorates such abnormalities even in the presence of IFN-γ stimulation. Our data thus suggest that preexposure to TNF or functionally similar cytokines inducing NF-κB-driven proinflammatory signaling during macrophage development is a prerequisite for accelerated inflammatory responses upon IFN-γ stimulation in BS.

Drug survival of anakinra and canakinumab in monogenic autoinflammatory diseases: observational study from the International AIDA Registry

OBJECTIVES

To investigate survival of interleukin (IL)-1 inhibitors in monogenic autoinflammatory disorders (mAID) through drug retention rate (DRR) and identify potential predictive factors of drug survival from a real-life perspective.

PATIENTS AND METHODS

Multicentre retrospective study analyzing patients affected by the most common mAID treated with anakinra or canakinumab. Survival curves were analyzed with the Kaplan-Meier method. Statistical analysis included a Cox-proportional hazard model to detect factors responsible for drug discontinuation.

RESULTS

Seventy-eight patients for a total of 102 treatment regimens were enrolled. The mean treatment duration was 29.59 months. The estimated DRR of IL-1 inhibitors at 12, 24, and 48 months of follow-up was 75.8%, 69.7% and 51.1%, respectively. Patients experiencing an adverse event had a significantly lower DRR (p = 0.019). In contrast, no significant differences were observed between biologic-naïve patients and those previously treated with biologic drugs (p = 0.985) Patients carrying high-penetrance mutations exhibited a significantly higher DRR compared with those with low-penetrance variants (p = 0.015). Adverse events were the only variable associated with a higher hazard of treatment withdrawal (HR 2.573 [CI: 1.223-5.411], p = 0.013) on regression analysis. A significant glucorticoid-sparing effect was observed (p < 0.0001).

CONCLUSIONS

IL-1 inhibitors display an excellent long-term effectiveness in terms of DRR, and their survival is not influenced by the biologic line of treatment. They display a favorable safety profile, that deserves however a close monitoring given its impact on treatment continuation. Special attention should be paid to molecular diagnosis and mutation penetrance, as patients carrying low-penetrance variants are more likely to interrupt treatment.

Loganin Alleviates Gout Inflammation by Suppressing NLRP3 Inflammasome Activation and Mitochondrial Damage

Gout is a type of inflammatory arthritis caused by the deposition of monosodium uric acid (MSU) crystals in tissues. The etiology of gout is directly linked to the NLRP3 inflammasome, since MSU crystals are NLRP3 inflammasome activators. Therefore, we decided to search for a small-molecule inhibitor of the NLRP3 inflammasome for the prevention of gout inflammation. We found that loganin suppressed MSU crystals-induced caspase-1 (p20) and interleukin (IL)-1β production and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) specks formation in mouse primary macrophages, showing its ability to inhibit the NLRP3 inflammasome. In an air pouch inflammation model, oral administration of loganin to mice prevented MSU crystals-induced production of mature IL-1β and IL-18 in air pouch exudates, resulting in decreased neutrophil recruitment. Furthermore, oral administration of loganin suppressed MSU crystals-induced gout inflammation in a mouse foot gout model, which was accompanied by the inhibition of the NLRP3 inflammasome. Loganin blocked de novo synthesis of mitochondrial DNA in air pouches and foot tissues injected with MSU crystals. Consistently, loganin prevented MSU crystals-induced mitochondrial damage in macrophages, as it increased mitochondrial membrane potential and decreased the amount of mitochondrial reactive oxygen species. These data demonstrate that loganin suppresses NLRP3 inflammasome activation by inhibiting mitochondrial stress. These results suggest a novel pharmacological strategy to prevent gout inflammation by blocking NLRP3 inflammasome activation and mitochondrial dysfunction.

Combined treatment of Taraxaci Herba and R7050 alleviates the symptoms of herpes simplex virus-induced Behçet's disease in rats

Background

Behçet's disease (BD) is a chronic inflammatory systemic disease that affects multiple organs. The causes of BD are still unknown, but it is primarily characterized by autoimmune reaction in the blood vessels. Current research focuses on treatments that can reduce the non-typical inflammatory responses of BD. Nevertheless, studies on improving the inflammatory effect of BD using inflammation mechanisms are still insufficient. Therefore, we conducted the integrated treatments related to inflammation modulation and achieved alleviation of symptoms in BD mice.

Methods

To understand the complex etiology of BD and compare its management, the herpes simplex virus (HSV)-induced BD mouse model was used. In order to alleviate the inflammatory response in BD mice, Taraxaci Herba (TH, herbal medicine), R7050-a TNFα inhibitor, and a mixture of TH and R7050 were injected for 2 weeks repetitively. The SCORAD index was examined to evaluate the cutaneous inflammations. In addition, histological changes and inflammatory factors were analyzed.

Results

Repetitive injection of TH and/or R7050 reduced the symptoms of BD and significantly decreased IL-6, IL-1β, and TNFα in blood sera. Moreover, this treatment reduced the ulcers and the deterioration of skin.

Conclusions

The results of our study showed that the down-regulation of inflammatory factors is related to the control of immune responses in BD models, suggesting that a mixed drug treatment may be more effective in improving the condition of BD.

New variant in the IL1RN-gene (DIRA) associated with late-onset, CRMO-like presentation

OBJECTIVE

To report a chronic recurrent multifocal osteomyelitis (CRMO)-like clinical phenotype with multisystem inflammation associated with a novel gene variant in the spectrum of IL-1-mediated diseases.

METHODS

A 3-year-old boy presented with recurrent episodes of fever, serositis, pancreatitis and high inflammatory markers with onset at age 13 months. At age 3 years, he started limping. Imaging revealed multifocal pelvic bone inflammation suggestive of CRMO. Autoinflammation panel testing was non-contributory. Whole exome sequencing (WES) and advanced IL-1 pathway analysis was conducted.

RESULTS

WES identified a novel homozygous interleukin receptor 1 (IL1RN) variant (c.62C>G; p. Ser21*) (NM_173842.2). Functional analysis of IL1RN mRNA and IL-1 receptor antagonist (IL-1RA) protein confirmed the diagnosis of a deficiency of the IL-1 receptor antagonist (DIRA). Treatment with the nonselective IL-1 inhibitor anakinra resulting in rapid remission; switch to the selective IL-1β antagonist canakinumab led to a flare within 6 weeks. Re-start of anakinra recaptured remission, last documented at the recent 19-month follow-up.

CONCLUSION

This is the first report of a novel late-onset DIRA confirmed by advanced diagnostic testing. In patients with systemic inflammation and CRMO-like bone lesions, IL1RN testing should be considered; even in the absence of skin manifestations. Non-selective IL-1 inhibition is an effective therapy.

Inflammasome Sensor NLRP1 Confers Acquired Drug Resistance to Temozolomide in Human Melanoma

Cancer cells gain drug resistance through a complex mechanism, in which nuclear factor-κB (NF-κB) and interleukin-1β (IL-1β) are critical contributors. Because NACHT, LRR and PYD domains-containing protein (NLRP) inflammasomes mediate IL-1β maturation and NF-κB activation, we investigated the role of inflammasome sensor NLRP1 in acquired drug resistance to temozolomide (TMZ) in melanoma. The sensitivity of melanoma cells to TMZ was negatively correlated with the expression levels of O6-methylguanine-DNA methyltransferase (MGMT), the enzyme to repair TMZ-induced DNA lesions. When MGMT-low human melanoma cells (1205Lu and HS294T) were treated with TMZ for over two months, MGMT was upregulated, and cells became resistant. However, the resistance mechanism was independent of MGMT, and the cells that acquired TMZ resistance showed increased NLRP1 expression, NLRP inflammasome activation, IL-1β secretion, and NF-κB activity, which contributed to the acquired resistance to TMZ. Finally, blocking IL-1 receptor (IL-1R) signaling with IL-1R antagonist decreased TMZ-resistant 1205Lu tumor growth in vivo. Although inflammation has been associated with drug resistance in various cancers, our paper is the first to demonstrate the involvement of NLRP in the development of acquired drug resistance. Because drug-tolerant cancer cells become cross-tolerant to other classes of cancer drugs, NLRP1 might be a suitable therapeutic target in drug-resistant melanoma, as well as in other cancers.

Recent advances in the NEK7-licensed NLRP3 inflammasome activation: Mechanisms, role in diseases and related inhibitors

The nucleotide-binding oligomerization domain (NOD)-like receptor containing pyrin domain 3 (NLRP3) inflammasome is a high-molecular-weight complex mediated by the activation of pattern-recognition receptors (PRRs) seed in innate immunity. Once NLRP3 is activated, the following recruitment of the adapter apoptosis-associated speck-like protein containing a caspase recruitment domain (CARD) (ASC) and procaspase-1 would be initiated. Cleavage of procaspase-1 into active caspase-1 then leads to the maturation of the precursor forms of interleukin (IL)-1β and IL-18 into biologically active IL-1β and IL-18. The activation of NLRP3 inflammasome is thought to be tightly associated with a regulator never in mitosis A (NIMA)-related kinase 7 (NEK7), apart from other signaling events such as K⁺ efflux and reactive oxygen species (ROS). Plus, the NLRP3 inflammasome has been linked to various metabolic disorders, chronic inflammation and other diseases. In this review, we firstly describe the cellular/molecular mechanisms of the NEK7-licensed NLRP3 inflammasome activation. Then we detail the potential inhibitors that can selectively and effectively modulate either the NEK7-NLRP3 complex itself or the related molecular/cellular events. Finally, we describe some inhibitors as promising therapeutic strategies for diverse diseases driven by NLRP3 inflammasome.

Effect of anti-interleukin-1 treatment on quality of life in children with colchicine-resistant familial Mediterranean fever: A single-center experience

AIM

The aim of this study is to evaluate the clinical parameters, acute-phase reactants, side effects, genetic mutations among colchicine-resistant Familial Mediterranean fever (FMF) patients who received anti-interleukin-1 (anti-IL-1) treatment. We also evaluate the quality of life and school attendance among colchicine-resistant FMF patients, in relation to treatment with anti-IL-1.

INTRODUCTION

Familial Mediterranean fever is the most common inherited autoinflammatory disorder. Although the main treatment of FMF is colchicine, a small group of patients are resistant to colchicine treatment. Anti-IL-1 treatment is promising in colchicine-resistant patients due to excessive IL-1β production in pathogenesis. The aim of this study is to evaluate the quality of life and school attendance rates among colchicine-resistant FMF patients after anti-IL-1 treatment.

METHODS

This is a single center retrospective study of 25 pediatric colchicine-resistant FMF patients treated with anti-IL-1 treatment. Autoinflammatory Disease Activity Index (AIDAI) was used for disease activity assessment. School attendance rates were evaluated before and after treatment.

RESULTS

There were 25 patients with FMF (11 M/14 F) who were treated with anakinra or canakinumab for various indications (colchicine-resistant recurrent febrile attacks in 20, colchicine-related side effects in 2, subclinical inflammation in 3 patients). Only 3 patients developed side effects with anakinra (2 headache, 1 urticarial rash). There was a significant decrease in the frequency of attacks, acute-phase reactants (erythrocyte sedimentation rate and C-reactive protein), AIDAI and physician's and patient's global assessment scores and improvement in school attendance rates. At the last follow-up, all patients were in remission, and only 3 had subclinical inflammation.

CONCLUSION

Anti-IL-1 treatment is quite effective in children with colchicine-resistant FMF patients, proven with improved AIDAI scores and school attendance rates. In the long term by lowering disease activation even development of amyloidosis may be prevented.

Safety, tolerability and pharmacokinetics and pharmacodynamics of HL2351, a novel hybrid fc-fused interleukin-1 receptor antagonist, in healthy subjects: A first-in-human study

AIMS

We performed a first-in-human study with HL2351, a novel hybrid Fc-fused interleukin (IL)-1 receptor antagonist, to evaluate its tolerability, pharmacokinetics and pharmacodynamics (PD) after a single subcutaneous (SC) administration in healthy subjects.

METHODS

A randomized, double-blind, placebo- and active-controlled, dose-escalation study was conducted. Eligible subjects randomly received a single SC administration of HL2351 (1, 2, 4, 8 and 12 mg/kg) or placebo in a ratio of 8:2. Subjects in the active-controlled group received a single SC administration of anakinra at 100 mg. Serial blood samples were collected for pharmacokinetics and PD analyses. An ex-vivo activation test was performed to evaluate the PD using peripheral blood mononuclear cells treated with IL-1β. Anti-HL2351 antibodies were determined at baseline and 29 days postdose. Tolerability was assessed throughout the study.

RESULTS

HL2351 was eliminated more slowly than anakinra (terminal half-life: 27.21-45.28 vs 3.97 h). Serum concentrations of HL2351 were increased dose-proportionally. The mean apparent clearance of HL2351 were 0.6, 0.66, 0.75, 0.51, 0.65 L/h at 1, 2, 4, 8 and 12 mg/kg, respectively. The percent inhibition of IL-6 expression varied widely (range: 0-92.1%), showing no clear trend or discernible difference between HL2351, anakinra and placebo. HL2351 was well tolerated after a single SC administration.

CONCLUSION

HL2351 was well tolerated and showed linear pharmacokinetic characteristics after a single SC administration at doses up to 12 mg/kg in healthy subjects. HL2351 remained in the body 7-11 times longer than anakinra. HL2351 can be developed as a potential therapeutic alternative to anakinra.

Patients with tumour necrosis factor (TNF) receptor-associated periodic syndrome (TRAPS) are hypersensitive to Toll-like receptor 9 stimulation

Tumour necrosis factor receptor-associated periodic syndrome (TRAPS) is a hereditary autoinflammatory disorder characterized by recurrent episodes of fever and inflammation. It is associated with autosomal dominant mutations in TNFRSF1A, which encodes tumour necrosis factor receptor 1 (TNF-R1). Our aim was to understand the influence of TRAPS mutations on the response to stimulation of the pattern recognition Toll-like receptor (TLR)-9. Peripheral blood mononuclear cells (PBMCs) and serum were isolated from TRAPS patients and healthy controls: serum levels of 15 proinflammatory cytokines were measured to assess the initial inflammatory status. Interleukin (IL)-1β, IL-6, IL-8, IL-17, IL-22, tumour necrosis factor (TNF)-α, vascular endothelial growth factor (VEGF), interferon (IFN)-γ, monocyte chemoattractant protein 1 (MCP-1) and transforming growth factor (TGF)-β were significantly elevated in TRAPS patients' sera, consistent with constitutive inflammation. Stimulation of PBMCs with TLR-9 ligand (ODN2006) triggered significantly greater up-regulation of proinflammatory signalling intermediates [TNF receptor-associated factor (TRAF 3), IL-1 receptor-associated kinase-like 2 (IRAK2), Toll interacting protein (TOLLIP), TRAF6, phosphorylated transforming growth factor-β-activated kinase 1 (pTAK), transforming growth factor-β-activated kinase-binding protein 2 (TAB2), phosphorylated TAK 2 (pTAB2), IFN-regulatory factor 7 (IRF7), receptor interacting protein (RIP), nuclear factor kappa B (NF-κB) p65, phosphorylated NF-κB p65 (pNF-κB p65) and mitogen-activated protein kinase kinase (MEK1/2)] in TRAPS patients' PBMCs. This up-regulation of proinflammatory signalling intermediates and raised serum cytokines occurred despite concurrent anakinra treatment and no overt clinical symptoms at time of sampling. These novel findings further demonstrate the wide-ranging nature of the dysregulation of innate immune responses underlying the pathology of TRAPS and highlights the need for novel pathway-specific therapeutic treatments for this disease.

Canakinumab for the treatment of hyperimmunoglobulin D syndrome

INTRODUCTION

Mevalonate Kinase Deficiency (MKD) is a rare monogenic autoinflammatory disorder (AID) with autosomal recessive inheritance caused by mutations in the MVK gene. It includes hyperimmunoglobulinemia D syndrome (HIDS) and mevalonic aciduria (a severe form). Patients have recurrent inflammatory attacks with high fever, gastrointestinal symptoms, lymphadenopathy, splenomegaly, arthralgia, rash, pharyngitis, aphtosis and constitutional complaints. Heightened understanding of molecular mechanisms in monogenic autoinflammatory disorders has provided tools for targeted treatment. HIDS is an extrinsic inflammasomopathy and is responsive to anti-IL-1 therapies, such as the recombinant IL-1-receptor antagonist anakinra, the monoclonal antibody against IL-1b canakinumab (CAN), and the recombinant IL-1R fusion protein rilonacept. Areas covered: CAN is a human monoclonal anti-IL-1β antibody that binds with high affinity and neutralizes the activity of IL-1 β. Both observational registries and some case reports have seemed promising in the efficacy of CAN in the HIDS treatment. Two clinical trials have corroborated CAN as an effective and safe drug. Expert commentary: CAN is effective and safe for the treatment of HIDS patients. Some data suggest these patients may need higher dosage or shorter dosing interval than other AIDs, to achieve and maintain complete clinical and laboratory response. Reported adverse events were mild, most often non-complicated infections.

Inflammation and pericarditis: Are neutrophils actors behind the scenes?

The morbidity of acute pericarditis is increasing over time impacting on patient quality of life. Recent clinical trials focused especially on clinical aspects, with a modest interest in pathophysiological mechanisms. This narrative review, based on papers in English language obtained via PubMed up to April 2018, aims at focusing on the role of the innate immunity in pericarditis and discussing future potential therapeutic strategies impacting on disease pathophysiology. In developed countries, most cases of pericarditis are referred to as idiopathic, although etiological causes have been described, with autoreactive/lymphocytic, malignant, and infectious ones as the most frequent causes. Apart the known impairment of the adaptive immunity, recently a large body evidence indicated the central role of the innate immune system in the pathogenesis of recurrent pericarditis, starting from similarities with autoinflammatory diseases. Accordingly, the "inflammasome" has been shown to behave as an important player in pericarditis development. Similarly, the beneficial effect of colchicine in recurrent pericarditis confirms that neutrophils are important effectors as colchicine, which can block neutrophil chemotaxis, interferes with neutrophil adhesion and recruitment to injured tissues and abrogate superoxide production. Anyway, the role of the adaptive immune system in pericarditis cannot be reduced to a black or white issue as mechanisms often overlap. Therefore, we believe that more efficient therapeutic strategies have to be investigated by targeting neutrophil-derived mediators (such as metalloproteinases) and disentangling the strict interplay between neutrophils and platelets. In this view, some progress has been done by using the recombinant human interleukin-1 receptor antagonist anakinra.

Identification and validation of uterine stimulant methylergometrine as a potential inhibitor of caspase-1 activation

Inflammasomes are intracellular multiprotein complexes of the innate immune system. Upon an inflammatory insult, such as infection or intracellular damage, a nucleotide-binding oligomerization domain-like receptor (NLR) sensor protein and the adaptor protein ASC (apoptosis-associated speck-like protein containing a caspase activation and recruitment domain) are assembled to activate protease procaspase-1. This protease processes pro-IL-1β and pro-IL-18 cytokines, which are released to induce the inflammatory response. De-regulation of inflammasome contributes to the progression of several diseases, such as Alzheimer’s disease, diabetes, cancer, inflammatory and autoimmune disorders. We herein describe the identification of methylergometrine (MEM), a drug currently used as a smooth muscle constrictor during postpartum hemorrhage, as an inhibitor of the inflammasome complex in ASC-mediated procaspase-1 activation screening. MEM inhibits the activation of the nucleotide-binding oligomerization domain-like receptor protein 1 (NLRP1) and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasomes in cellular models upon different pro-inflammatory stimuli. Our results suggest that MEM has the potential to reposition in the treatment of inflammatory diseases with the advantages of established safety and clinical data.

Poly-gamma-glutamic acid from Bacillus subtilis upregulates pro-inflammatory cytokines while inhibiting NLRP3, NLRC4 and AIM2 inflammasome activation

Poly-gamma-glutamic acid (γ-PGA) is a natural, edible and non-toxic polymer synthesized by Bacillus subtilis and is suggested as a safe biomaterial for the use in hydrogels and vaccine adjuvants. However, the effect of γ-PGA on inflammasome activation has not yet been studied in macrophages. Inflammasomes, which are intracellular multi-protein complexes, promote acute and chronic inflammation via interleukin-1β or interleukin-18 maturation, and they are known targets for metabolic syndromes and cancer. In this study, we observed that γ-PGA attenuated NLRP3, NLRC4 and AIM2 inflammasome activation, whereas it upregulated pro-inflammatory cytokine expression in human and murine macrophages. Although γ-PGA had conflicting effects on cytokine production and maturation, it clearly alleviated the severity of lipopolysaccharide-induced endotoxin shock in an animal model. Thus, we suggest γ-PGA as a candidate to control inflammasome-mediated disorders.

New mosaic tiles in childhood hereditary autoinflammatory disorders

The protean clinical phenotypes of hereditary autoinflammatory disorders (HAID) are caused by abnormal activation of innate immunity and consist of seemingly unprovoked inflammatory flares localized to multiple organs, such as the skin, joints, serosal membranes, gut, and central nervous system. Different mutations in genes implied in activation of the interleukin-1 (IL-1)-structured inflammasome, cytoskeletal signaling and apoptosis contribute to the pathogenesis of different HAID, which mostly start in childhood with self-limited flares unrelated to infectious agents, autoantibody production or autoreactive cells. Though IL-1 remains pivotal in many inflammasome-mediated diseases, other cytokinopathies involving IL-18, nuclear factorκ-B, interferons, and tumor necrosis factor have provided new horizons in the definition of HAID of children: the list of HAID has expanded as a consequence of a better understanding of their pathogenetic molecular mechanisms and also application of new genetic technologies. However, diagnosis of most HAID is clinical and focused on several evidence-based criteria sets: their discrimination remains challenging for unexperienced pediatricians as there are no universally accepted algorithms, and a still relevant number of patients may linger without any clarifying genetic analysis, whose interpretation combined with processing of treatment options should be discussed on a multidisciplinary basis.

Therapeutics for APOL1 nephropathies: putting out the fire in the podocyte

APOL1 nephropathies comprise a range of clinical and pathologic syndromes, which can be summarized as focal segmental glomerulosclerosis, in various guises, and arterionephrosclerosis, otherwise known as hypertensive kidney diseases. Current therapies for these conditions may achieve therapeutic targets, reduction in proteinuria and control of blood pressure, respectively, but often fail to halt the progressive decline in kidney function. It appears that current therapies fail to address certain underlying critical pathologic processes that are driven, particularly in podocytes and microvascular cells, by the APOL1 renal risk genetic variants. Mechanisms hypothesized to be responsible for APOL1 variant-associated cell injury can be summarized in five domains: increased APOL1 gene expression, activation of inflammasomes, activation of protein kinase R, electrolyte flux across plasma or intracellular membranes, and altered endolysosomal trafficking associated with endoplasmic reticulum stress. We briefly review the available evidence for these five mechanisms and suggest possible novel therapeutic approaches.

Elevated Expression of the NLRP3 Inflammasome and Its Correlation with Disease Activity in Adult-onset Still Disease

OBJECTIVE

The dysregulation of the NLRP3 (NLR containing a pyrin domain) inflammasome is involved in autoinflammatory diseases. Adult-onset Still disease (AOSD) is regarded as an autoinflammatory disease. However, the pathogenic involvement of NLRP3 inflammasome in AOSD remains unclear and NLRP3 activators in AOSD are currently unknown.

METHODS

The mRNA expression of NLRP3 inflammasome signaling in peripheral blood mononuclear cells (PBMC) from 34 patients with AOSD and 14 healthy subjects was determined using quantitative-PCR (qPCR). The changes in mRNA and protein levels of NLRP3 inflammasome signaling in PBMC treated with the potential activator [imiquimod (IMQ)] or inhibitor of NLRP3 were evaluated using qPCR and immunoblotting, respectively. The supernatant levels of interleukin (IL)-1β and IL-18 were determined by ELISA.

RESULTS

Significantly higher mRNA levels of NLRP3 inflammasome signaling were observed in patients with AOSD compared with healthy controls. NLRP3 expressions were positively correlated with disease activity in patients with AOSD. IMQ (an effective Toll-like receptor 7 ligand; 10 µg/ml and 25 µg/ml) stimulation of PBMC from patients with AOSD induced dose-dependent increases of mRNA expression of NLRP3 (mean ± standard error of the mean, 2.06 ± 0.46 and 6.05 ± 1.84, respectively), caspase-1 (1.81 ± 0.23 and 4.25 ± 0.48), IL-1β (5.68 ± 1.51 and 12.13 ± 3.71), and IL-18 (2.32 ± 0.37 and 4.81 ± 0.51) compared with controls (all p < 0.005). IMQ stimulation of PBMC from patients similarly induced greater increases in protein expressions of NLRP3 inflammasome compared with controls. The protein expressions of NLRP3, IL-1β, and IL-18 on PBMC significantly decreased after treatment with NLRP3 inhibitor in patients with AOSD.

CONCLUSION

Increased expression of NLRP3 inflammasome and its positive correlation with disease activity in AOSD suggest its involvement in disease pathogenesis. IMQ upregulated expressions of NLRP3 inflammasome signaling, and IMQ might be an activator of NLRP3 inflammasome in AOSD.

Interleukin-1 receptor antagonist expression is inversely associated with outcomes of hepatitis B-related acute-on-chronic liver failure

Interleukin-1 receptor antagonist (IL-1ra) is a naturally occurring anti-inflammatory antagonist of the proinflammatory cytokine IL-1, a critical factor in many inflammatory diseases. The aim of the present study was to investigate the role of IL-1ra in hepatitis B-related acute-on-chronic liver failure (HB-ACLF). Serum cytokine concentrations were measured using a Q-Plex array in 31 patients with HB-ACLF, 28 patients with acute hepatitis B (AHB), 31 patients with chronic hepatitis B (CHB) and 15 healthy control patients (HCs). Additionally, peripheral blood mononuclear cells (PBMCs) from patients with HB-ACLF were incubated with PBS or lipopolysaccharide and/or different concentrations of recombinant human IL-1ra (rhIL-1ra) in vitro. Cytokines in the supernatant were measured using a Q-Plex array. The median serum IL-1ra level in patients with HB-ACLF was 186.46 (350.22) pg/ml, which was significantly higher than all other groups (AHB, P=0.012; CHB, P<0.001; HCs, P<0.001). However, the ratio of IL-1ra/IL-1β was significantly lower in the HB-ACLF group compared with the AHB group (P=0.048). Median serum IL-1ra levels in patients with AHB were also significantly increased compared with those in the CHB (P<0.001) and HC (P<0.001) groups. Patients who succumbed to mortality within 3 months of the study were found to have significantly lower IL-1ra concentrations (P=0.02) and IL-1ra/IL-1β ratios (P=0.007) compared with surviving patients with HB-ACLF. Furthermore, serum IL-1ra concentrations were negatively associated with the Model for End-stage Liver Disease score (r=−0.870; P<0.001). Cytokine secretion by PBMCs in vitro was significantly inhibited in a dose-dependent manner by rhIL-1ra (125–500 ng/ml; all P<0.05). These results suggest that IL-1ra is associated with the development of liver inflammation, which is reduced in patients with HB-ACLF and inversely associated with disease severity.

Periodic fevers and autoinflammatory syndromes in childhood

Recurrent fever is a common presentation in paediatric practice and can be caused by a wide variety of diseases including autoinflammatory conditions. The innate immune system plays an essential role in the 'first line' response to infection through mediation of inflammatory responses. Inflammasomes are part of the regulatory process for this system and result in the production of the powerful pro-inflammatory cytokine interleukin-1B. Dysregulation of inflammasomes, and Interleukin 1 production, contributes to the pathogenesis of autoinflammatory diseases. This review focuses on described periodic fever syndromes (PFS) which are now collectively referred to as autoinflammatory syndromes. Conditions discussed include periodic fever aphthous stomatitis pharyngitis and cervical adenopathy, familial Mediterranean fever, tumour necrosis factor receptor-associated periodic syndromes, hyperimmunoglobulinaemia D and the cryopyrin-associated periodic syndromes. Presenting features, complications, diagnostic and treatment approaches for these conditions are discussed. Nonetheless, as most of these conditions are rare and may have significant long-term complications, it is recommended that they be managed in consultations with a physician experienced in managing PFS.

Cytokine Profile in Gout: Inflammation Driven by IL-6 and IL-18?

INTRODUCTION

Gout is considered to be an autoinflammatory disease and the presence of monosodium urate (MSU) crystals stimulates activation of NPRL3 inflammasome and subsequently caspase-1, generating production of active IL-1β and IL-18. However, the association between serum cytokines levels and clinical manifestations of the disease is not yet well understood. We evaluated the serum profile of proinflammatory cytokines (IL-1β, IL-6, IL-8, IL-17A, IL-18, IL-22, and IL-23) and described their relationship with clinical and laboratory data.

METHODOLOGY

Thirty-nine male patients with gout (GG) were assessed for clinical and laboratory variables and cytokine levels were measured by ELISA. For the purposes of comparison, 34 males with no previous history of arthritis were also included in the study (CG).

RESULTS

Seventeen participants (43%) exhibited active arthritis on evaluation. Levels of IL-18 were significantly higher in patients in relation to the CG (p = 0.0013). No statistically significant differences were found between the GG and CG for the other measured cytokines. There was a moderate correlation between IL-18 and ESR (R = 0.43, p = 0.0073), CRP (R = 0.47, p = 0.0025), and serum levels of IL-6 (R = 0.36, p = 0.023). An association was observed between serum levels of IL-6 and the presence of tophi (p = 0.005) and deformities (p = 0.0008), as well as a correlation between this cytokine and ESR (R = 0.41, p = 0.011) and CRP (R = 0.48, p = 0.02).

CONCLUSIONS

IL-18 is associated with inflammatory activity in gout, as well as with IL-6 levels, while IL-6 is associated with clinical and laboratory activity, the presence of tophi and articular deformities, and may be a prognostic marker of this pathology.

Homozygosity for the V377I mutation in mevalonate kinase causes distinct clinical phenotypes in two sibs with hyperimmunoglobulinaemia D and periodic fever syndrome (HIDS)

Objective

Mevalonate kinase (MVK) deficiency is a rare autosomal recessive auto-inflammatory disorder characterised by recurring episodes of fever associated with multiple non-specific inflammatory symptoms and caused by mutations in the MVK gene. The phenotypic spectrum is wide and depends mostly on the nature of the mutations. Hyperimmunoglobulinaemia D and periodic fever syndrome (HIDS) is a relatively mild presentation and predominantly associated with a c.1129G>A (p.V377I) mutation in the MVK gene. We report cases of two sisters homozygous for this mutation but exhibiting distinct (symptomatic vs asymptomatic) phenotypes.

Methods

Patient history was obtained; physical and clinical examination and laboratory tests were performed; lipopolysaccharide (LPS) response of peripheral blood mononuclear cells was quantified.

Results

Low MVK enzymatic activity is not necessarily associated with inflammatory symptoms. Increased inflammatory cytokine secretion in response to LPS is associated with symptomatic MVK deficiency.

Conclusions

Individuals who are homozygous for the common p.V377I mutation in the MVK gene may not display the characteristic inflammatory episodes diagnostic of MKD and thus may be lost for correct and timely diagnosis.

IL-1 Receptor Signaling on Graft Parenchymal Cells Regulates Memory and De Novo Donor-Reactive CD8 T Cell Responses to Cardiac Allografts

Reperfusion of organ allografts induces a potent inflammatory response that directs rapid memory T cell, neutrophil, and macrophage graft infiltration and their activation to express functions mediating graft tissue injury. The role of cardiac allograft IL-1 receptor (IL-1R) signaling in this early inflammation and the downstream primary alloimmune response was investigated. When compared with complete MHC-mismatched wild-type cardiac allografts, IL-1R(-/-) allografts had marked decreases in endogenous memory CD8 T cell and neutrophil infiltration and expression of proinflammatory mediators at early times after transplant, whereas endogenous memory CD4 T cell and macrophage infiltration was not decreased. IL-1R(-/-) allograft recipients also had marked decreases in de novo donor-reactive CD8, but not CD4, T cell development to IFN-γ-producing cells. CD8 T cell-mediated rejection of IL-1R(-/-) cardiac allografts took 3 wk longer than wild-type allografts. Cardiac allografts from reciprocal bone marrow reconstituted IL-1R(-/-)/wild-type chimeric donors indicated that IL-1R signaling on graft nonhematopoietic-derived, but not bone marrow-derived, cells is required for the potent donor-reactive memory and primary CD8 T cell alloimmune responses observed in response to wild-type allografts. These studies implicate IL-1R-mediated signals by allograft parenchymal cells in generating the stimuli-provoking development and elicitation of optimal alloimmune responses to the grafts.

The inflammasome and IL-1β: implications for the treatment of inflammatory diseases

The bioactive form of IL-1β, a key immunoregulatory and proinflammatory cytokine, is produced by the inflammasome - a caspase-1 activating molecular platform - in response to selected danger-associated molecular patterns and pathogen-associated molecular patterns. Advances in understanding the role of IL-1β in inflammatory conditions has resulted in IL-1β becoming a therapeutic target for a number of inflammatory diseases beyond the rare monogenic autoinflammatory diseases characterized by aberrant inflammasome function and enhanced bioactive IL-1β production. In the monogenic autoinflammatory diseases known as cryopyrin-associated periodic syndromes, neutralization of IL-1β results in a rapid and sustained reduction in disease severity without severe side effects, which has consequently driven off-label applications of IL-1β-targeted therapy in other inflammatory diseases. This review summarizes inflammatory diseases for which accumulating evidence suggests a therapeutic potential for IL-1β antagonists.

Apigenin supplementation protects the development of dextran sulfate sodium-induced murine experimental colitis by inhibiting canonical and non-canonical inflammasome signaling pathways

The present study was designed to elucidate the protective effects of dietary apigenin (API) enrichment in a chronic colitis model induced by DSS in mice. Inflammatory mediators and the possible role of canonical and non-canonical NLRP3 inflammasome signaling pathways in the beneficial effects of API under chronic inflammatory conditions were also explored. Six-week-old mice were randomized in four dietary groups: sham and control groups received standard diet (SD), and other two groups were fed with API at 0.1%. After 30days, all groups except sham received 3% DSS in drinking water for 5days followed by a regime of 21days of water. Our results revealed that dietary API supplementation decreased the macroscopic and microscopic damage signs of colitis; also, it was capable to down-regulate mPGES, COX-2 and iNOS enzyme colonic expressions and to decrease serum matrix metalloproteinase (MMP-3) levels. Similarly, API diet reduced IL-1β and TNF-α proinflammatory cytokine secretions in primary LPS-stimulated splenocytes. Furthermore, we demonstrated that API anti-inflammatory activity was related with an inhibition of both canonical and non-canonical NLRP3 inflammasome pathways by decreasing proinflammatory IL-1β and IL-18 cytokine levels as a consequence of regulation of cleaved caspase-1 and caspase-11 enzymes. We conclude that API supplement might provide a basis for developing a new dietary strategy for the prevention of chronic ulcerative colitis.

Targeting the inflammasome in rheumatic diseases

Activation of the inflammasome, a protein complex responsible for many cellular functions, including the activation of the proinflammatory cytokines interleukin (IL)-1β and IL-18, has been identified as a key participant in many rheumatic diseases including autoimmune, inflammatory, and autoinflammatory syndromes. This review will discuss the recent advances in understanding the role of this complex in various rheumatic diseases. Furthermore, it will focus on available therapies, which directly and indirectly target the inflammasome and its downstream cytokines to quiet inflammation and possibly dampen autoimmune processes.

Offloading treatment is linked to activation of proinflammatory cytokines and start of bone repair and remodeling in Charcot arthropathy patients

BACKGROUND

Proinflammatory cytokines are an integral part of the osteolytic activity of Charcot arthropathy but are also central to normal bone healing. As there are no previous longitudinal studies investigating their role during the recovery phase of Charcot, we set out to monitor systemic levels of proinflammatory cytokines from Charcot presentation until a clinically and radiographically documented chronic state has been reached.

METHODS

Twenty-eight consecutive Charcot patients were monitored during 2 years by repeated foot radiographs, MRI and plasma levels of interleukin [IL]-6, IL-8, IL-1β, Tumor Necrosis Factor [TNF]-α, and IL-1 receptor antibody (IL-1RA). Charcot patients were treated with total contact cast (TCC) on the first day of inclusion. Neuropathic diabetic controls (n = 20) and Healthy subjects (n = 20) served as reference.

RESULTS

Plasma IL-6, IL-8, IL-1β and TNF-α in the acute and chronic phase of Charcot were below or at the level of diabetic controls and healthy, whereas IL-1RA/IL-1β ratio was continuously higher in Charcot patients. IL-6, TNF-α and IL-1RA began to increase one week after offloading to reach a peak after 4 months before gradually receding.

CONCLUSIONS

A sustained increase of IL-6 and TNF-α starting shortly after offloading and paralleled by accelerated bone healing on radiographs, suggest that offloading, by activating the inflammatory stage, has a key role to play in the onset of coupled bone remodeling. High IL-1RA/IL-1β ratio in Charcot patients at presentation supports a counter-balancing anti-inflammatory role for IL-1RA in the acute phase whereas a high ratio after two years, possibly due to renewed weight-bearing on a deformed foot, signal need for continued anti-inflammatory activity and contradicts a "cold" biological state in the chronic phase.

Schisandrin B induces an Nrf2-mediated thioredoxin expression and suppresses the activation of inflammasome in vitro and in vivo

Reactive oxygen species (ROS)-mediated activation of inflammasome is involved in the development of a wide spectrum of diseases. We aimed to investigate whether (-)schisandrin B [(-)Sch B], a phytochemical that can induce cellular antioxidant response, can suppress the inflammasome activation. Results showed that (-)Sch B can induce an nuclear factor erythroid 2-related factor 2-driven thioredoxin expression in primary peritoneal macrophages and cultured RAW264.7 macrophages. A 4-h priming of peritoneal macrophages with LPS followed by a 30-min incubation with ATP caused the activation of caspase 1 and the release of IL-1β, indicative of inflammasome activation. Although LPS/ATP did not activate inflammasome in RAW264.7 macrophages, it caused the ROS-dependent c-Jun N-terminal kinase1/2 (JNK1/2) activation and an associated lactate dehydrogenase (LDH) release in RAW264.7 macrophages, an indication of cytotoxicity. (-)Sch B suppressed the LPS/ATP-induced activation of caspase 1 and release of IL-1β in peritoneal macrophages. (-)Sch B also attenuated the LPS/ATP-induced ROS production, JNK1/2 activation and LDH release in RAW264.7 macrophages. The ability of (-)Sch B to suppress LPS/ATP-mediated inflammation in vitro was further confirmed by an animal study, in which schisandrin B treatment (2 mmol/kg p.o.) ameliorated the Imject Alum-induced peritonitis, as indicated by suppressions of caspase1 activation and plasma IL-1β level. The ensemble of results suggests that (-)Sch B may offer a promising prospect for preventing the inflammasome-mediated disorders.

Inflammatory markers and cardiometabolic diseases

OBJECTIVES

A growing body of evidence emerges that obesity, metabolic syndrome, type 2 diabetes and cardiovascular disease are intimately related to chronic inflammation.

METHODS

A narrative review summarizing the most recent data of the literature describing the pathological implications of inflammation in obese patients with cardiometabolic disorders.

RESULTS

Besides high-sensitive C-reactive protein, various circulating or in situ inflammatory markers have been identified, presumably reflecting the presence of inflammation in various key-organs (visceral adipose tissue, skeletal muscle, pancreatic islets, liver, intestine, arterial wall). Available data support the concept that targeting inflammation, not only reduces systemic inflammatory markers, but also improves insulin sensitivity and ameliorates glucose control in insulin-resistant patients, thus potentially reducing the risk of cardiovascular complications.

CONCLUSION

These observations confirm the role of inflammation in cardiometabolic diseases and support the development of pharmacological strategies that aim at reducing inflammation, especially in patients with type 2 diabetes.

Commentary: rituximab, adalimumab, etanercept, tocilizumab--are biologics the future for Graves' orbitopathy?

Graves' orbitopathy (GO) is the main extrathyroidal manifestation of Graves disease and a rare disease in its severe expressions. Moderate-to-severe GO represents a therapeutic challenge. Established nonsurgical treatments include glucocorticoids (most commonly given intravenously), cyclosporine, and orbital radiotherapy. However, results are not always satisfactory, and a relevant proportion of GO patients need some kind of rehabilitative surgery (orbital decompression, squint surgery, eyelid surgery) once GO is inactivated. Biological agents have been used in several autoimmune disorders, with contrasting results. Current better understanding of the pathogenesis of GO allows us to identify pathways that might be the target of biologics. T and B cells, cytokines, and peroxisome proliferator-activated receptor-γ might all be targeted by treatments. It is extremely difficult to design and perform sufficiently powered randomized controlled studies that may support the role of targeted therapies. For the time being, rituximab, a monoclonal antibody depleting CD20-positive B cells, appears the most promising agent, but so far its use relies on the results of small and uncontrolled studies.

Exertional leg pain in familial Mediterranean fever: a manifestation of an underlying enthesopathy and a marker of more severe disease

OBJECTIVE

Exertional leg pain is a characteristic musculoskeletal manifestation of familial Mediterranean fever (FMF). We aimed to define the frequency and characteristics of exertional leg pain in a large cohort of FMF patients and to evaluate for additional signs and symptoms of spondyloarthritis (SpA) in this patient population.

METHODS

FMF patients were allocated into study or control groups based on the presence or absence of exertional leg pain. Randomly selected patients underwent magnetic resonance imaging (MRI) of the ankle as well as plain radiography of the sacroiliac joints.

RESULTS

The prevalence of exertional leg pain among the 170 FMF patients included in the study was 58.2%. Patients with exertional leg pain had significantly more joint attacks (74.7% versus 40.8%; P < 0.0001), fever attacks (35.4% versus 15.5%; P = 0.004), and pleuritis attacks (48.5% versus 29.6%; P = 0.013) as well as more attacks per year. Elevations of inflammation markers were significantly more frequent among the study group (for the erythrocyte sedimentation rate, 44.4% of patients versus 21.1% of patients; P = 0.016) (for the C-reactive protein level, 48.4% of patients versus 31.8% of patients; P = 0.013), and M694V homozygosity was more prevalent among the study group (45.5% versus 21.1%; P = 0.001). Signs compatible with enthesopathy on MRI were observed in 73.5% of patients in the study group and in 33.3% of patients in the control group (P = 0.046). Definite SpA was diagnosed in 41.2% of the patients in the study group compared to none of the controls (P = 0.07) (odds ratio 1.7 [95% confidence interval 1.2-2.3]).

CONCLUSION

Exertional leg pain is a common manifestation of FMF and is a marker of a more severe disease phenotype. Additionally, exertional leg pain is frequently associated with sacroiliitis and an underlying ankle enthesopathy and should therefore be considered a new feature of SpA.

Targeting the NLRP3 inflammasome in chronic inflammatory diseases: current perspectives

The inflammasome is a molecular platform formed by activation of an innate immune pattern recognition receptor seed, such as NLRP3. Once activated, NLRP3 recruits the adapter ASC (apoptosis-related speck-like protein containing a caspase recruitment domain), which in turn recruits procaspase-1. Procaspase-1 autocatalyzes its cleavage and activation, resulting in maturation of the precursor forms of interleukin (IL)-1β and IL-18 into active proinflammatory cytokines and initiation of pyroptotic cell death. The NLRP3 inflammasome has been implicated in the pathogenesis of a wide variety of diseases, including genetically inherited autoinflammatory conditions as well as chronic diseases in which NLRP3 is abnormally activated. The NLRP3 inflammasome has been linked to diseases such as Alzheimer’s disease, atherosclerosis, metabolic syndrome, and age-related macular degeneration. In this review, we describe the NLRP3 inflammasome complex and its activation in disease, and detail the current therapies that modulate either the NLRP3 inflammasome complex itself or the two cytokines it is responsible for activating, ie, IL-1β and IL-18.

A functional inflammasome activation assay differentiates patients with pathogenic NLRP3 mutations and symptomatic patients with low penetrance variants

Cryopyrin-associated periodic syndromes (CAPS) are characterized by recurrent episodes of systemic inflammation caused by mutations in the NLRP3 gene. Besides confirmed pathogenic NLRP3 mutations, patients with CAPS-like symptoms frequently show low penetrance variants in NLRP3. The disease relevance of these variants is inconsistent. In this study, we investigated if an inflammasome activation assay differentiates between patients with confirmed pathogenic CAPS mutations, patients with low penetrance NLRP3 variants (V198M and Q703K) and healthy controls. The release of mature IL-1β, IL-18, and caspase-1 into cell culture supernatants after 4h of inflammasome stimulation was significantly increased in patients with confirmed pathogenic CAPS mutations compared to low penetrance NLRP3 variants and controls. IL-1β secretion in CAPS patients correlated with disease severity. This inflammasome activation assay differentiates between autoinflammation patients with confirmed pathogenic CAPS mutations and patients with low penetrance NLRP3 variants, and points towards alternative pathophysiological mechanisms in low penetrance NLRP3 variants.

Emerging therapeutic targets for Gaucher disease

INTRODUCTION

Gaucher disease (GD) is an inherited metabolic disorder caused by mutations in the glucocerebrosidase (GBA1) gene. Although infusions of recombinant GBA ameliorate the systemic effects of GD, this therapy has no effect on the neurological manifestations. Patients with the neuronopathic forms of GD (nGD) are often severely disabled and die prematurely. The search for innovative drugs is thus urgent for the neuronopathic forms.

AREAS COVERED

Here we briefly summarize the available treatments for GD. We then review recent studies of the molecular pathogenesis of GD, which suggest new avenues for therapeutic development.

EXPERT OPINION

Existing treatments for GD are designed to target the primary consequence of the inborn defects of sphingolipid metabolism, that is, lysosomal accumulation of glucosylceramide (GlcCer). Here we suggest that targeting other pathways, such as those that are activated as a consequence of GlcCer accumulation, may also have salutary clinical effects irrespective of whether excess substrate persists. These pathways include those implicated in neuroinflammation, and specifically, receptor-interacting protein kinase-3 (RIP3) and related components of this pathway, which appear to play a vital role in the pathogenesis of nGD. Once available, inhibitors to components of the RIP kinase pathway will hopefully offer new therapeutic opportunities in GD.

Anti-inflammatory agents to treat or prevent type 2 diabetes, metabolic syndrome and cardiovascular disease

INTRODUCTION

There is a growing body of evidence to suggest that chronic silent inflammation is a key feature in abdominal obesity, metabolic syndrome, type 2 diabetes (T2DM) and cardiovascular disease (CVD). These observations suggest that pharmacological strategies, which reduce inflammation, may be therapeutically useful in treating obesity, type 2 diabetes and associated CVD.

AREA COVERED

The article covers novel strategies, using either small molecules or monoclonal antibodies. These strategies include: approaches targeting IKK-b-NF-kB (salicylates, salsalate), TNF-α (etanercept, infliximab, adalimumab), IL-1β (anakinra, canakinumab) and IL-6 (tocilizumab), AMP-activated protein kinase activators, sirtuin-1 activators, mammalian target of rapamycin inhibitors and C-C motif chemokine receptor 2 antagonists.

EXPERT OPINION

The available data supports the concept that targeting inflammation improves insulin sensitivity and β-cell function; it also ameliorates glucose control in insulin-resistant patients with inflammatory rheumatoid diseases as well in patients with metabolic syndrome or T2DM. Although promising, the observed metabolic effects remain rather modest in most clinical trials. The potential use of combined anti-inflammatory agents targeting both insulin resistance and insulin secretion appears appealing but remains unexplored. Large-scale prospective clinical trials are underway to investigate the safety and efficacy of different anti-inflammatory drugs. Further evidence is needed to support the concept that targeting inflammation pathways may represent a valuable option to tackle the cardiometabolic complications of obesity.

Effectiveness and tuberculosis-related safety profile of interleukin-1 blocking agents in the management of Behçet's disease

Behçet's disease (BD) is a multi-systemic disorder of unknown etiology characterized by relapsing oral-genital ulcers, uveitis, and involvement of the articular, gastrointestinal, neurologic, and vascular systems. Although the primum movens of this condition remains unknown, a tangled plot combining autoimmune and autoinflammatory pathways has been hypothesized to explain its start and recurrence. In-depth analysis of BD pathogenetic mechanisms, involving dysfunction of multiple proinflammatory molecules, has opened new modalities of treatment: different agents targeting interleukin-1 have been studied in recent years to manage the most difficult and multi-resistant cases of BD. Growing experience with anakinra, canakinumab and gevokizumab is discussed in this review, highlighting the relative efficacy of each drug upon the protean BD clinical manifestations. Safety and tolerability of interleukin-1 antagonists in different doses have been confirmed by numerous observational studies on both large and small cohorts of patients with BD. In particular, the potential for Mycobacterium tuberculosis reactivation and tuberculosis development appears to be significantly lower with interleukin-1 blockers compared to tumor necrosis factor-α inhibitors, thus increasing the beneficial profile of this approach.

Biological treatments in Behçet's disease: beyond anti-TNF therapy

Behçet's disease (BD) is universally recognized as a multisystemic inflammatory disease of unknown etiology with chronic course and unpredictable exacerbations: its clinical spectrum varies from pure vasculitic manifestations with thrombotic complications to protean inflammatory involvement of multiple organs and tissues. Treatment has been revolutionized by the progressed knowledge in the pathogenetic mechanisms of BD, involving dysfunction and oversecretion of multiple proinflammatory molecules, chiefly tumor necrosis factor- (TNF-) α, interleukin- (IL-) 1β, and IL-6. However, although biological treatment with anti-TNF-α agents has been largely demonstrated to be effective in BD, not all patients are definite responders, and this beneficial response might drop off over time. Therefore, additional therapies for a subset of refractory patients with BD are inevitably needed. Different agents targeting various cytokines and their receptors or cell surface molecules have been studied: the IL-1 receptor has been targeted by anakinra, the IL-1 by canakinumab and gevokizumab, the IL-6 receptor by tocilizumab, the IL12/23 receptor by ustekinumab, and the B-lymphocyte antigen CD-20 by rituximab. The aim of this review is to summarize all current experiences and the most recent evidence regarding these novel approaches with biological drugs other than TNF-α blockers in BD, providing a valuable addition to the actually available therapeutic armamentarium.

A pro-inflammatory signalome is constitutively activated by C33Y mutant TNF receptor 1 in TNF receptor-associated periodic syndrome (TRAPS)

Mutations in TNFRSF1A encoding TNF receptor 1 (TNFR1) cause the autosomal dominant TNF receptor-associated periodic syndrome (TRAPS): a systemic autoinflammatory disorder. Misfolding, intracellular aggregation, and ligand-independent signaling by mutant TNFR1 are central to disease pathophysiology. Our aim was to understand the extent of signaling pathway perturbation in TRAPS. A prototypic mutant TNFR1 (C33Y), and wild-type TNFR1 (WT), were expressed at near physiological levels in an SK-Hep-1 cell model. TNFR1-associated signaling pathway intermediates were examined in this model, and in PBMCs from C33Y TRAPS patients and healthy controls. In C33Y-TNFR1-expressing SK-Hep-1 cells and TRAPS patients’ PBMCs, a subtle, constitutive upregulation of a wide spectrum of signaling intermediates and their phosphorylated forms was observed; these were associated with a proinflammatory/antiapoptotic phenotype. In TRAPS patients’ PBMCs, this upregulation of proinflammatory signaling pathways was observed irrespective of concurrent treatment with glucocorticoids, anakinra or etanercept, and the absence of overt clinical symptoms at the time that the blood samples were taken. This study reveals the pleiotropic effect of a TRAPS-associated mutant form of TNFR1 on inflammatory signaling pathways (a proinflammatory signalome), which is consistent with the variable and limited efficacy of cytokine-blocking therapies in TRAPS. It highlights new potential target pathways for therapeutic intervention.