The effect of colchicine on pyrin and pyrin interacting proteins

Recent Insights in Pyrin Inflammasome Activation: Identifying Potential Novel Therapeutic Approaches in Pyrin-Associated Autoinflammatory Syndromes

Pyrin is a cytosolic protein encoded by the MEFV gene, predominantly expressed in innate immune cells. Upon activation, it forms an inflammasome, a multimolecular complex that enables the activation and secretion of IL-1β and IL-18. In addition, the Pyrin inflammasome activates Gasdermin D leading to pyroptosis, a highly pro-inflammatory cell death. Four autoinflammatory syndromes are associated with Pyrin inflammasome dysregulation: familial Mediterranean fever, hyper IgD syndrome/mevalonate kinase deficiency, pyrin-associated autoinflammation with neutrophilic dermatosis, and pyogenic arthritis, pyoderma gangrenosum, and acne syndrome. In this review, we discuss recent advances in understanding the molecular mechanisms regulating the two-step model of Pyrin inflammasome activation. Based on these insights, we discuss current pharmacological options and identify a series of existing molecules with therapeutic potential for the treatment of pyrin-associated autoinflammatory syndromes.

Inflammasome Signaling, Thromboinflammation, and Venous Thromboembolism

Venous thromboembolism (VTE) remains a major health burden despite anticoagulation advances, suggesting incomplete management of pathogenic mechanisms. The NLRP3 (NACHT-, LRR- and pyrin domain-containing protein 3) inflammasome, interleukin (IL)-1, and pyroptosis are emerging contributors to the inflammatory pathogenesis of VTE. Inflammasome pathway activation occurs in patients with VTE. In preclinical models, inflammasome signaling blockade reduces venous thrombogenesis and vascular injury, suggesting that this therapeutic approach may potentially maximize anticoagulation benefits, protecting from VTE occurrence, recurrence, and ensuing post-thrombotic syndrome. The nonselective NLRP3 inhibitor colchicine and the anti-IL-1β agent canakinumab reduce atherothrombosis without increasing bleeding. Rosuvastatin reduces primary venous thrombotic events at least in part through lipid-lowering independent mechanisms, paving the way to targeted anti-inflammatory strategies in VTE. This review outlines recent preclinical and clinical evidence supporting a role for inflammasome pathway activation in venous thrombosis, and discusses the, yet unexplored, therapeutic potential of modulating inflammasome signaling to prevent and manage VTE.

The pyrin inflammasome aggravates inflammatory cell migration in patients with familial Mediterranean fever

BACKGROUND

Familial Mediterranean fever (FMF) is an autoinflammatory disease caused by pathogenic variants of the MEFV gene, which encodes pyrin. Leukocyte migration to serosal sites is a key event during inflammation in FMF. The pyrin inflammasome is a multiprotein complex involved in inflammation. Here, we aimed to determine the relationship between inflammatory cell migration and the pyrin inflammasome in FMF patients.

METHODS

Monocytes were isolated from blood samples collected from patients with FMF, healthy controls, and a patient with cryopyrin-associated periodic syndrome (CAPS), which served as a disease control. Inflammasome proteins were analyzed under inflammasome activation and inhibition by western blotting. Cell migration assays were performed with the isolated primary monocytes as well as THP-1 monocytes and THP-1-derived macrophages.

RESULTS

When the pyrin inflammasome was suppressed, migration of monocytes from FMF patients was significantly decreased compared to the migration of monocytes from the CAPS patient and healthy controls. Cell line experiments showed a relationship between pyrin inflammasome activation and cell migration.

CONCLUSIONS

These findings suggest that the increased cell migration in FMF is due to the presence of more active pyrin inflammasome. This study contributes to our understanding of the role of pyrin in inflammatory cell migration through inflammasome formation.

IMPACT

The pyrin inflammasome may play a role in inflammatory cell migration. FMF patients show a pyrin inflammasome-dependent increase in inflammatory cell migration. Correlations between the pyrin inflammasome and cell migration were observed in both THP-1 monocytes and THP-1-derived macrophages.

Transmigration of Neutrophils From Patients With Familial Mediterranean Fever Causes Increased Cell Activation

Familial Mediterranean fever (FMF) is caused by pyrin-encoding MEFV gene mutations and characterized by the self-limiting periods of intense inflammation, which are mainly mediated by a massive influx of polymorphonuclear neutrophils (PMNs) into the inflamed sites. Perturbation of actin polymerization by different pathogens was shown to activate the pyrin inflammasome. Our aim was to test whether cytoskeletal dynamics in the absence of pathogens may cause abnormal activation of PMNs from FMF patients. We also aimed to characterize immunophenotypes of circulating neutrophils and their functional activity. Circulating PMNs displayed heterogeneity in terms of cell size, granularity and immunophenotypes. Particularly, PMNs from the patients in acute flares (FMF-A) exhibited a characteristic of aged/activated cells (small cell size and granularity, up-regulated CXCR4), while PMNs form the patients in remission period (FMF-R) displayed mixed fresh/aged cell characteristics (normal cell size and granularity, up-regulated CD11b, CD49d, CXCR4, and CD62L). The findings may suggest that sterile tissue-infiltrated PMNs undergo reverse migration back to bone marrow and may explain why these PMNs do not cause immune-mediated tissue damage. A multidirectional expression of FcγRs on neutrophils during acute flares was also noteworthy: up-regulation of FcγRI and down-regulation of FcγRII/FcγRIII. We also observed spontaneous and fMPL-induced activation of PMNs from the patients after transmigration through inserts as seen by the increased expression of CD11b and intracellular expression of IL-1β. Our study suggests heightened sensitivity of mutated pyrin inflammasome towards cytoskeletal modifications in the absence of pathogens.

Interleukin-1 and the Inflammasome as Therapeutic Targets in Cardiovascular Disease

The intracellular sensing protein termed NLRP3 (for NACHT, LRR, and PYD domains-containing protein 3) forms a macromolecular structure called the NLRP3 inflammasome. The NLRP3 inflammasome plays a major role in inflammation, particularly in the production of IL (interleukin)-1β. IL-1β is the most studied of the IL-1 family of cytokines, including 11 members, among which are IL-1α and IL-18. Here, we summarize preclinical and clinical findings supporting the key pathogenetic role of the NLRP3 inflammasome and IL-1 cytokines in the formation, progression, and complications of atherosclerosis, in ischemic (acute myocardial infarction), and nonischemic injury to the myocardium (myocarditis) and the progression to heart failure. We also review the clinically available IL-1 inhibitors, although not currently approved for cardiovascular indications, and discuss other IL-1 inhibitors, not currently approved, as well as oral NLRP3 inflammasome inhibitors currently in clinical development. Canakinumab, IL-1β antibody, prevented the recurrence of ischemic events in patients with prior acute myocardial infarction in a large phase III clinical trial, including 10 061 patients world-wide. Phase II clinical trials show promising data with anakinra, recombinant IL-1 receptor antagonist, in patients with ST-segment-elevation acute myocardial infarction or heart failure with reduced ejection fraction. Anakinra also improved outcomes in patients with pericarditis, and it is now considered standard of care as second-line treatment for patients with recurrent/refractory pericarditis. Rilonacept, a soluble IL-1 receptor chimeric fusion protein neutralizing IL-1α and IL-1β, has also shown promising results in a phase II study in recurrent/refractory pericarditis. In conclusion, there is overwhelming evidence linking the NLRP3 inflammasome and the IL-1 cytokines with the pathogenesis of cardiovascular diseases. The future will likely include targeted inhibitors to block the IL-1 isoforms, and possibly oral NLRP3 inflammasome inhibitors, across a wide spectrum of cardiovascular diseases.

Update on the management of colchicine resistant Familial Mediterranean Fever (FMF)

Background

Familial Mediterranean Fever (FMF), an autoinflammatory disease, is characterized by self-limited inflammatory attacks of fever and polyserositis along with high acute phase response. Although colchicine remains the mainstay in treatment, intolerance and resistance in a certain portion of patients have been posing a problem for physicians.

Main body

Like many autoimmune and autoinflammatory diseases, many colchicine-resistant or intolerant FMF cases have been successfully treated with biologics. In addition, many studies have tested the efficacy of biologics in treating FMF manifestations.

Conclusion

Since carriers of FMF show significantly elevated levels of serum TNF alpha, IL-1, and IL-6, FMF patients who failed colchicine were successfully treated with anti IL-1, anti IL-6, or TNF inhibitors drugs. It is best to use colchicine in combination with biologics.

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome: main features and an algorithm for clinical practice

Periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome is a recurrent fever syndrome of early childhood with increasing number of adult-onset cases. Although it is a self-limited disease, it may negatively affect the quality of life. The aim of this review is to present a detailed analysis of PFAPA syndrome and an algorithm for diagnosis, therapeutic options, and evaluation of outcome. A comprehensive literature search was conducted through the Cochrane Library, Scopus, and MEDLINE/PubMed databases. The main topics covered are the epidemiology, clinical manifestations, diagnosis, differential diagnosis, etiopathogenesis, genetics, management, disease course and prognosis, disease in adults, unsolved issues, and unmet needs in PFAPA. The diagnosis of PFAPA is mainly based on clinical classification criteria. The most relevant hypothesis for pathogenesis is that dysregulated immune system in a genetically predisposed individual responds to a yet unidentified trigger in an exaggerated way. The pedigree analyses suggest a genetic background for the disease with an autosomal dominant pattern of inheritance. For management, single-dose corticosteroids during attacks and tonsillectomy remain the most effective therapies, while colchicine is a promising option to decrease attack frequency. There remain unsolved issues in PFAPA such as the exact etiopathogenesis and genetic background, the reason why the inflammation is restricted to the oropharyngeal lymphoid tissue, reasons for clock-work regularity of attacks, and self-limited disease course. There is need for a valid diagnostic criteria set with a high performance for both children and adults and consensus on management of PFAPA.

Cyclic Stretching Exacerbates Tendinitis by Enhancing NLRP3 Inflammasome Activity via F-Actin Depolymerization

Modern molecular techniques have highlighted the presence of inflammation throughout the spectrum of tendinopathy. Previous studies have suggested that excessive inflammation in the tendon is a major factor leading to poor clinical treatment. Furthermore, the NLRP3 inflammasome, as a new term, is closely associated with the pathogenesis of many diseases. In the present study, we examined whether the NLRP3 inflammasome contributes to the development of tendinitis and whether cyclic stretching plays a prominent role in inflammation in the tendon. In the present study, we showed that hydrogen peroxide (H₂O₂) remarkably enhances the expression and release of IL-1β, TNF-α, and IL-6. The maturation of IL-1β, induced by H₂O₂, depends on the activation of the NLRP3 inflammasome. Cyclic stretching enhances the maturation of IL-1β via promoting H₂O₂-induced NLRP3 inflammasome activation in tenocytes. Furthermore, we also found that the depolymerization of filamentous actin (F-actin) was required for cyclic stretching-enhanced NLRP3 inflammasome activation. The present study suggests that NLRP3 inflammasome plays an important regulatory role in the pathogenesis of tendinitis. Disruption of the cytoskeleton by cyclic stretching exerts a proinflammatory effect via further activating the NLRP3/IL-1β pathway and hence contributes to tendinitis. These results may provide theoretical support for a new treatment strategy for preventing excessive inflammation in the tendon.

Correlation of Secretory Activity of Neutrophils With Genotype in Patients With Familial Mediterranean Fever

OBJECTIVE

Familial Mediterranean fever (FMF) is an autoinflammatory disorder caused by pyrin-encoding MEFV mutations. Patients present with recurrent but self-limiting episodes of acute inflammation and often have persistent subclinical inflammation. The pathophysiology is only partially understood, but neutrophil overactivation is a hallmark of the disease. S100A12 is a neutrophil-derived proinflammatory danger signal that is strongly elevated in active FMF. This study was undertaken to characterize the secretory activity of neutrophils in vitro and investigate the association of S100A12 with disease activity and genotype in patients with FMF.

METHODS

Neutrophils from FMF patients carrying the p.M694V mutation (1 compound heterozygous and 5 homozygous) and neutrophils from 4 healthy control subjects were purified and stimulated in vitro. Neutrophil secretion of S100A12, interleukin-18 (IL-18), IL-1β, and caspase 1 was determined. Based on these in vitro analyses, serum concentrations of S100A12, IL-18, and IL-1β were also analyzed in 128 clinically and genetically characterized patients with FMF.

RESULTS

In vitro, unstimulated neutrophils from p.M694V-positive patients spontaneously secreted more S100A12, IL-18, and caspase 1 compared to neutrophils from healthy controls. Serum concentrations of S100A12 correlated with disease activity and genotype, with the levels being highest in homozygous patients and with compound heterozygotes displaying higher levels than heterozygotes. Compared to individuals negative for the p.M694V mutation, heterozygous, compound heterozygous, or homozygous p.M694V-positive patients had higher serum levels of S100A12 and IL-18 during inactive and subclinical disease.

CONCLUSION

The FMF phenotype is known to be more severe in patients carrying the p.M694V mutation. This report describes 2 molecules secreted by unconventional secretory pathways, S100A12 and IL-18, whose concentrations correlated with clinical disease activity and genotype in patients with FMF. In this clinically and genetically heterogeneous disease, management of these surrogate markers might help to improve patient care and outcomes.

Does familial Mediterranean fever affect cognitive function in children? Electrophysiological preliminary study

OBJECTIVES

Familial Mediterranean fever (FMF) is a periodic autoinflammatory disease with subclinical inflammation occurring between attacks. The aim of the study was to prospectively evaluate the cognitive function of children diagnosed with FMF that were under colchicine therapy and compare them with healthy controls through electrophysiologically event-related potentials (ERPs) study.

METHODS

Twelve children with FMF and 12 healthy controls were included in the study. During the electroencephalography recordings, all participants were instructed to discriminate rare stimuli (target stimuli) from frequent stimuli (standard stimuli) by pressing a botton on a mouse immediately following the target stimulus. P300, the cognitive component of ERP, was obtained in response to target stimuli and its amplitude and latency were measured.

RESULTS

The amplitude of the P300 of the FMF patients was higher and the latencies of the P300 of the FMF patients were shorter than the amplitudes and latencies of control patients, respectively. The difference between the groups was statistically significant for amplitude but not for latency.

CONCLUSIONS

Cognitive processing reflecting allocation of attention and visual processing speed seems not to be negatively affected in FMF patients with homozygous M694V mutations undergoing colchicine treatment. As this study is unique in its evaluation of the cognitive function of children with FMF, these findings may be helpful for counseling families and patients affected by the condition.

Familial Mediterranean Fever: Recent Developments in Pathogenesis and New Recommendations for Management

Familial Mediterranean fever (FMF) is the most common monogenic autoinflammatory disease (AID) affecting mainly the ethnic groups originating from Mediterranean basin. The disease is characterized by self-limited inflammatory attacks of fever and polyserositis along with elevated acute phase reactants. FMF is inherited autosomal recessively; however, a significant proportion of heterozygotes also express the phenotype. FMF is caused by mutations in the MEFV gene coding for pyrin, which is a component of inflammasome functioning in inflammatory response and production of interleukin-1β (IL-1β). Recent studies have shown that pyrin recognizes bacterial modifications in Rho GTPases, which results in inflammasome activation and increase in IL-1β. Pyrin does not directly recognize Rho modification but probably affected by Rho effector kinase, which is a downstream event in the actin cytoskeleton pathway. Recently, an international group of experts has published the recommendations for the management of FMF. Colchicine is the mainstay of FMF treatment, and its regular use prevents attacks and controls subclinical inflammation in the majority of patients. Furthermore, it decreases the long-term risk of amyloidosis. However, a minority of FMF patients fail to response or tolerate colchicine treatment. Anti-interleukin-1 drugs could be considered in these patients. One should keep in mind the possibility of non-compliance in colchicine-non-responders. Although FMF is a relatively well-described AID and almost 20 years has passed since the discovery of the MEFV gene, there are still a number of unsolved problems about it such as the exact mechanism of the disease, symptomatic heterozygotes and their treatment, and the optimal management of colchicine resistance.

F-actin dampens NLRP3 inflammasome activity via Flightless-I and LRRFIP2

NLRP3 and ASC are able to form a large multimeric complex called inflammasome in response to a number danger signals. The NLRP3 inflammasome is required for the activation of caspase-1 and subsequent maturation of pro-IL-1β into active IL-1β. Although the mechanisms regulating the formation and activity of NLRP3 inflammasome are yet not fully elucidated, data suggest that the assembly of NLRP3 inflammasome requires microtubules to induce the proximity of ASC and NLRP3. In this study we show that microfilaments (F-actin) inhibit NLRP3 inflammasome activity and interact with NLRP3 and ASC. We demonstrate that the inhibition depends on the actin polymerization state but not on the active polymerization process. In ATP- or nigericin-activated macrophages, our data further indicate that Flightless-I (FliI) and leucine-rich repeat FliI-interaction protein 2 (LRRFIP2) are required for the co-localization of NLRP3, ASC and F-actin. We also established that the ability of Ca²⁺ to accentuate the activity of NLRP3 inflammasome is abrogated in FliI- and LRRFIP2-knockdown macrophages, suggesting that Ca²⁺ signaling requires the presence of FliI and LRRFIP2. Accordingly, we observed that Ca²⁺/FliI-dependent severing of F-actin suppresses F-actin/FliI/LRRFIP2-dependent NLRP3 inflammasome inhibition leading to increase IL-1β production. Altogether, our results unveil a new function of F-actin in the regulation of NLRP3 inflammasome activity strengthening the importance of cytoskeleton in the regulation of inflammation.

Update on Pyrin Functions and Mechanisms of Familial Mediterranean Fever

Mutations in the MEFV gene, which encodes the protein named pyrin (also called marenostrin or TRIM20), are associated with the autoinflammatory disease familial Mediterranean fever (FMF). Recent genetic and immunologic studies uncovered novel functions of pyrin and raised several new questions in relation to FMF pathogenesis. The disease is clinically heterogeneous reflecting the complexity and multiplicity of pyrin functions. The main functions uncovered so far include its involvement in innate immune response such as the inflammasome assemblage and, as a part of the inflammasome, sensing intracellular danger signals, activation of mediators of inflammation, and resolution of inflammation by the autophagy of regulators of innate immunity. Based on these functions, the FMF-associated versions of pyrin confer a heightened sensitivity to a variety of intracellular danger signals and postpone the resolution of innate immune responses. It remains to be demonstrated, however, what kind of selective advantage the heterozygous carriage conferred in the past to be positively selected and maintained in populations from the Mediterranean basin.

Transcriptional induction of the heat shock protein B8 mediates the clearance of misfolded proteins responsible for motor neuron diseases

Neurodegenerative diseases (NDs) are often associated with the presence of misfolded protein inclusions. The chaperone HSPB8 is upregulated in mice, the human brain and muscle structures affected during NDs progression. HSPB8 exerts a potent pro-degradative activity on several misfolded proteins responsible for familial NDs forms. Here, we demonstrated that HSPB8 also counteracts accumulation of aberrantly localized misfolded forms of TDP-43 and its 25 KDa fragment involved in most sporadic cases of Amyotrophic Lateral Sclerosis (sALS) and of Fronto Lateral Temporal Dementia (FLTD). HSPB8 acts with BAG3 and the HSP70/HSC70-CHIP complex enhancing the autophagic removal of misfolded proteins. We performed a high-through put screening (HTS) to find small molecules capable of inducing HSPB8 in neurons for therapeutic purposes. We identified two compounds, colchicine and doxorubicin, that robustly up-regulated HSPB8 expression. Both colchicine and doxorubicin increased the expression of the master regulator of autophagy TFEB, the autophagy linker p62/SQSTM1 and the autophagosome component LC3. In line, both drugs counteracted the accumulation of TDP-43 and TDP-25 misfolded species responsible for motoneuronal death in sALS. Thus, analogs of colchicine and doxorubicin able to induce HSPB8 and with better safety and tolerability may result beneficial in NDs models.

Colchicine--Update on mechanisms of action and therapeutic uses

OBJECTIVES

To review the literature and provide an update on the mechanisms of action and therapeutic uses of oral colchicine in arthritis and inflammatory conditions.

METHODS

We performed PubMed database searches through June 2014 for relevant studies in the English literature published since the last update of colchicine in 2008. Searches encompassed colchicine mechanisms of action and clinical applications in medical conditions. A total of 381 articles were reviewed.

RESULTS

The primary mechanism of action of colchicine is tubulin disruption. This leads to subsequent down regulation of multiple inflammatory pathways and modulation of innate immunity. Newly described mechanisms include various inhibitory effects on macrophages including the inhibition of the NACHT-LRRPYD-containing protein 3 (NALP3) inflammasome, inhibition of pore formation activated by purinergic receptors P2X7 and P2X2, and stimulation of dendritic cell maturation and antigen presentation. Colchicine also has anti-fibrotic activities and various effects on endothelial function. The therapeutic use of colchicine has extended beyond gouty arthritis and familial Mediterranean fever, to osteoarthritis, pericarditis, and atherosclerosis.

CONCLUSION

Further understanding of the mechanisms of action underlying the therapeutic efficacy of colchicine will lead to its potential use in a variety of conditions.

Colchicine: old and new

Although colchicine has been a focus of research, debate, and controversy for thousands of years, the US Food and Drug Administration just approved it in 2009. Over the past decade, advances in the knowledge of colchicine pharmacology, drug safety, and mechanisms of action have led to changes in colchicine dosing and to potential new uses for this very old drug. In this review, we discuss the pharmacologic properties of colchicine and summarize what is currently known about its mechanisms of action. We then discuss and update the use of colchicine in a variety of illnesses, including rheumatic and, most recently, cardiovascular diseases.

Non-canonical manifestations of familial Mediterranean fever: a changing paradigm

Paroxysmal crises of fever and systemic inflammation herald familial Mediterranean fever (FMF), considered as the archetype of all inherited systemic autoinflammatory diseases. Inflammatory bouts are characterized by short-term and self-limited abdominal, thoracic, and/or articular symptoms which subside spontaneously. Erysipelas-like findings, orchitis, and different patterns of myalgia may appear in a minority of patients. In recent years, many non-classical manifestations have been reported in the clinical context of FMF, such as vasculitides and thrombotic manifestations, neurologic and sensory organ abnormalities, gastrointestinal diseases, and even macrophage activation syndrome. As FMF left unrecognized and untreated is ominously complicated by the occurrence of AA-amyloidosis, it is highly desirable that diagnosis of this autoinflammatory disorder with its multiple clinical faces can be contemplated at whatever age and brought forward.

Clinical Review: Familial Mediterranean Fever-An Overview of Pathogenesis, Symptoms, Ocular Manifestations, and Treatment

Familial Mediterranean fever is an autoinflammatory multisystem disease, which most commonly affects patients from the Mediterranean basin. This review discusses the common polymorphisms in the MEFV gene as well as the role of pyrin in disease pathogenesis. Patients with familial Mediterranean fever typically develop peritonitis, pleuritis, arthritis, and fever. In addition, a number of authors have reported ophthalmic features. These case reports and series are further explored in this review. Colchicine has transformed the prognosis for patients with familial Mediterranean fever. The rationale for the use of colchicine, as well as the evidence for newer biologic agents is also covered.

The inflammasomes and autoinflammatory syndromes

Inflammation, a vital response of the immune system to infection and damage to tissues, can be initiated by various germline-encoded innate immune-signaling receptors. Among these, the inflammasomes are critical for activation of the potent proinflammatory interleukin-1 cytokine family. Additionally, inflammasomes can trigger and maintain inflammatory responses aimed toward excess nutrients and the numerous danger signals that appear in a variety of chronic inflammatory diseases. We discuss our understanding of how inflammasomes assemble to trigger caspase-1 activation and subsequent cytokine release, describe how genetic mutations in inflammasome-related genes lead to autoinflammatory syndromes, and review the contribution of inflammasome activation to various pathologies arising from metabolic dysfunction. Insights into the mechanisms that govern inflammasome activation will help in the development of novel therapeutic strategies, not only for managing genetic diseases associated with overactive inflammasomes, but also for treating common metabolic diseases for which effective therapies are currently lacking.

Mechanism of action of colchicine in the treatment of gout

PURPOSE

The aims of this article were to systematically review the literature about the mechanism of action of colchicine in the multimodal pathology of acute inflammation associated with gout and to consider the clinical utility of colchicine in other chronic inflammatory diseases.

METHODS

The English-language literature on PubMed was searched for articles published between 1990 and October 2013, with a cross-reference to citations across all years. Relevant articles pertaining to the mechanism of action of colchicine and the clinical applications of colchicine in gout and other inflammatory conditions were identified and reviewed.

FINDINGS

The molecular pathology of acute inflammation associated with gouty arthritis involves several concurrent pathways triggered by a variety of interactions between monosodium urate crystals and the surface of cells. Colchicine modulates multiple pro- and antiinflammatory pathways associated with gouty arthritis. Colchicine prevents microtubule assembly and thereby disrupts inflammasome activation, microtubule-based inflammatory cell chemotaxis, generation of leukotrienes and cytokines, and phagocytosis. Many of these cellular processes can be found in other diseases involving chronic inflammation. The multimodal mechanism of action of colchicine suggests potential efficacy of colchicine in other comorbid conditions associated with gout, such as osteoarthritis and cardiovascular disease.

IMPLICATIONS

Colchicine has multiple mechanisms of action that affect inflammatory processes and result in its utility for treating and preventing acute gout flare. Other chronic inflammatory diseases that invoke these molecular pathways may represent new therapeutic applications for colchicine.

Working the endless puzzle of hereditary autoinflammatory disorders

Hereditary autoinflammatory disorders encompass manifold dysfunctions of innate immunity caused by mutations in genes coding for the main characters of the inflammatory scene: most of these conditions have an early onset, ranging from the first days of life to the first decades, and include hereditary periodic fevers, NLRP-related diseases, granulomatous and pyogenic syndromes, which are basically characterized by upturned inflammasome activity and overproduction of bioactive interleukin (IL)-1β and other proinflammatory cytokines. The discovery of a causative link between autoinflammation and IL-1β release has improved our understanding of the intimate mechanisms of innate immunity, and has likewise led to the identification of extraordinary treatments for many of these disorders.

Contribution of the inflammasomes to autoinflammatory diseases and recent mouse models as research tools

Inflammasomes are multiprotein complexes that serve as activating platforms for the enzyme caspase-1 in response to various danger signals. Active caspase-1 can cleave the precursors of the pro-inflammatory cytokines IL-1β and IL-18 and thereby activate them. Deregulation of this cascade caused by mutations in genes coding for inflammasomal components and their interaction partners can lead to severe disease. This review summarizes the contribution of deregulated inflammasomes to the field of autoinflammatory syndromes. In addition, it gives insight into currently available mouse models that are used to study and characterize the role of the inflammasome components in the pathophysiology of these diseases.