The gene for familial Mediterranean fever, MEFV, is expressed in early leukocyte development and is regulated in response to inflammatory mediators

NLRP3, NLRP6, and NLRP12 are inflammasomes with distinct expression patterns

Inflammasomes are sensors that detect cytosolic microbial molecules or cellular damage, and in response they initiate a form of lytic regulated cell death called pyroptosis. Inflammasomes signal via homotypic protein-protein interactions where CARD or PYD domains are crucial for recruiting downstream partners. Here, we screened these domains from NLR family proteins, and found that the PYD domain of NLRP6 and NLRP12 could activate caspase-1 to induce cleavage of IL-1β and GSDMD. Inflammasome reconstitution verified that full length NLRP6 and NLRP12 formed inflammasomes in vitro, and NLRP6 was more prone to auto-activation. NLRP6 was highly expressed in intestinal epithelial cells (IEC), but not in immune cells. Molecular phylogeny analysis found that NLRP12 was closely related to NLRP3, but the activation mechanisms are different. NLRP3 was highly expressed in monocytes and macrophages, and was modestly but appreciably expressed in neutrophils. In contrast, NLRP12 was specifically expressed in neutrophils and eosinophils, but was not detectable in macrophages. NLRP12 mutations cause a periodic fever syndrome called NLRP12 autoinflammatory disease. We found that several of these patient mutations caused spontaneous activation of caspase-1 in vitro, which likely causes their autoinflammatory disease. Different cell types have unique cellular physiology and structures which could be perturbed by a pathogen, necessitating expression of distinct inflammasome sensors to monitor for signs of infection.

Interrupting an IFN-γ-dependent feedback loop in the syndrome of pyogenic arthritis with pyoderma gangrenosum and acne

OBJECTIVES

To study the molecular pathogenesis of PAPA (pyogenic arthritis, pyoderma gangrenosum and acne) syndrome, a debilitating hereditary autoinflammatory disease caused by dominant mutation in PSTPIP1.

METHODS

Gene knock-out and knock-in mice were generated to develop an animal model. THP1 and retrovirally transduced U937 human myeloid leukaemia cell lines, peripheral blood mononuclear cells, small interfering RNA (siRNA) knock-down, site-directed mutagenesis, cytokine immunoassays, coimmunoprecipitation and immunoblotting were used to study inflammasome activation. Cytokine levels in the skin were evaluated by immunohistochemistry. Responsiveness to Janus kinase (JAK) inhibitors was evaluated ex vivo with peripheral blood mononuclear cells and in vivo in five treatment-refractory PAPA patients.

RESULTS

The knock-in mouse model of PAPA did not recapitulate the human disease. In a human myeloid cell line model, PAPA-associated PSTPIP1 mutations activated the pyrin inflammasome, but not the NLRP3, NLRC4 or AIM2 inflammasomes. Pyrin inflammasome activation was independent of the canonical pathway of pyrin serine dephosphorylation and was blocked by the p.W232A PSTPIP1 mutation, which disrupts pyrin-PSTPIP1 interaction. IFN-γ priming of monocytes from PAPA patients led to IL-18 release in a pyrin-dependent manner. IFN-γ was abundant in the inflamed dermis of PAPA patients, but not patients with idiopathic pyoderma gangrenosum. Ex vivo JAK inhibitor treatment attenuated IFN-γ-mediated pyrin induction and IL-18 release. In 5/5 PAPA patients, the addition of JAK inhibitor therapy to IL-1 inhibition was associated with clinical improvement.

CONCLUSION

PAPA-associated PSTPIP1 mutations trigger a pyrin-IL-18-IFN-γ positive feedback loop that drives PAPA disease activity and is a target for JAK inhibition.

Effect of increasing doses of colchicine on the treatment of 333 COVID-19 inpatients

BACKGROUND

Previous research done in Bulgaria demonstrated a fivefold reduction in mortality from COVID-19 with increased doses of colchicine from two hospitals in the country. We report here a further 333 cases of COVID-19 inpatients, treated with different doses of colchicine and its effect on mortality.

MATERIALS AND METHODS

A case-control comparison from two additional hospitals was conducted between increased doses of colchicine and added bromhexine to standard of care (SOC) versus current SOC. Risk and odds ratio, as well as subgroup analysis, was conducted with newly reported data, alongside aggregate data from all hospital centers to determine the extent of mortality reduction in COVID-19 inpatients.

RESULTS

There was a clear reduction in the mortality of inpatients with increasing doses of colchicine-between twofold and sevenfold. Colchicine loading doses of 4 mg are more effective than those with 2 mg. Despite these doses being higher than the so-called "standard doses," colchicine inpatients experienced lower mortality than SOC patients (5.7% vs. 19.53%). This mortality benefit was evident in different age subgroups, with a 4-mg loading dose of colchicine proving slightly superior to a 2-mg loading dose. Colchicine led to an overall relative risk reduction of 70.7%, with SOC patients having 3.91 higher odds of death. The safety of the doses was not different than the reported in the summary of product characteristics.

CONCLUSION

Inpatients in Bulgaria with added colchicine and bromhexine to SOC achieved better clinical and mortality outcomes than those on SOC alone. These results question the World Health Organization-recommended strategy to inhibit viral replication. We posit that our treatment strategy to inhibit the Severe acute respiratory syndrome coronavirus 2 entry into the cell with inhaled bromhexine and the hyperactivated NLRP3 inflammasome with higher doses of colchicine, prevents the development of cytokine storm. The timing of the initiation of treatment seems critical.

Disordered GPR43/NLRP3 expression in peripheral leukocytes of patients with atrial fibrillation is associated with intestinal short chain fatty acids levels

BACKGROUND

Atrial fibrillation (AF) is associated with circulating inflammation. Short-chain fatty acids (SCFAs) derived from gut microbiota (GM) regulate leukocyte function and inhibit the release of inflammatory cytokines, which are partly mediated by the G-protein-coupled receptor 43 (GPR43) signaling. This study aimed to investigate the expression of GPR43/NOD-like receptors family pyrin domain containing 3 (NLRP3) in leukocytes and the interaction with intestinal SCFAs levels in AF patients.

METHODS

Expressions of GPR43 and NLRP3 mRNA in peripheral blood leukocytes from 23 AF patients and 25 non-AF controls were detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Expressions of leukocyte GPR43 and NLRP3 protein were evaluated by western blot analysis. The levels of plasma IL-1β were measured by enzyme-linked immunosorbent assay (ELISA). The fecal SCFAs levels based on GC/MS metabolome of corresponding 21 controls and 14 AF patients were acquired from our published dataset. To evaluate the expression of NLRP3 and GPR43 and the release of IL-1β, human THP-1 cells were stimulated with or without SCFAs (acetate, propionate, and butyrate), lipopolysaccharide (LPS), and nigericin in vitro, respectively.

RESULTS

Compared to the controls, the mRNA expression in peripheral leukocytes was significantly reduced in AF patients (P = 0.011) coupled with the increase in downstream leukocyte NLRP3 mRNA expression (P = 0.007) and plasma IL-1β levels (P < 0.001), consistent with changes in GPR43 and NLRP3 protein expression. Furthermore, leukocyte GPR43 mRNA levels were positively correlated with fecal GM-derived acetic acid (P = 0.046) and negatively correlated with NLRP3 mRNA expression (P = 0.024). In contrast to the negative correlation between left atrial diameter (LAD) and GPR43 (P = 0.008), LAD was positively correlated with the leukocyte NLRP3 mRNA levels (P = 0.024). Subsequent mediation analysis showed that 68.88% of the total effect of intestinal acetic acid on AF might be mediated by leukocyte GPR43/NLRP3. The constructed GPR43-NLRP3 score might have a predictive potential for AF detection (AUC = 0.81, P < 0.001). Moreover, SCFAs treatment increased GPR43 expression and remarkably reduced LPS/nigericin-induced NLRP3 expression and IL-1β release in human THP-1 cells in vitro.

CONCLUSIONS

Disrupted interactions between GPR43 and NLRP3 expression in peripheral blood leukocytes, associated with reduced intestinal GM-derived SCFAs, especially acetic acid, may be involved in AF development and left atrial enlargement by enhancing circulating inflammation.

Evaluation of the Inflammatory Response After Eradication of Helicobacter pylori in Patients With Familial Mediterranean Fever

PURPOSE

Evaluation of the inflammatory response after Helicobacter pylori (Hp) eradication in patients with Familial Mediterranean Fever (FMF) during the non-attack period and determining whether there is a change in the ongoing inflammation during the non-attack period.

MATERIALS AND METHODS

Sixty-four patients, who have not been eradicated for Hp in the last 2 years, diagnosed with FMF, and evaluated in the non-attack period, were included in the study. Hp eradication therapy was administered to patients who were found to be Hp-positive. C-reactive protein (CRP), high-sensitive C-reactive protein (hs-CRP), interleukin-6, interleukin-8, tumor necrosis factor-alpha, and serum amyloid A values were compared between the groups before and after eradication.

RESULTS

CRP and hs-CRP levels were found to be statistically higher in the FMF group than in the control group. A statistically significant decrease was found in the values of CRP and hs-CRP, in the number of patients with attacks, and in attack frequency after eradication in the Infected Patients compared to the values before eradication.

CONCLUSIONS

We determined a decrease in CRP and hs-CRP values, the number of patients with attacks, and attack frequency with the eradication of Infected Patients. In patients with FMF, in whom it has been proven by different studies that the inflammation continues during the non-attack period, it may be recommended to investigate the presence of Hp infection, which is thought to contribute to this inflammation and to give Hp eradication therapy to patients who are found positive to reduce the development of secondary complications caused by chronic inflammation.

Experimental models in Familial Mediterranean Fever (FMF): Insights into pathophysiology and therapeutic strategies

Familial Mediterranean Fever (FMF) is a recurrent polyserositis characterized by self-limiting episodes or attacks of fever along with serosal inflammation. It mainly impacts people of the Mediterranean and Middle Eastern basin. FMF is a recessive autoinflammatory condition caused by mutation in the MEFV gene located on chromosome 16p13. MEFV mutations lead to the activation of the pyrin inflammasome resulting in an uncontrolled release of IL-1β. Various in vitro, in vivo and ex vivo experimental models have been developed to further comprehend the etiology and pathogenesis of FMF. These models have been proven to be clinically relevant to human FMF and can provide significant information about biological systems with respect to this condition. Additionally, these models have provided pertinent contributions to the development of potent therapeutic strategies against FMF. In this review, we describe the different experimental models utilized in FMF and we focus primarily on the most widely used models that have produced prominent insights into the pathophysiology of the disease.

Pregnancy outcomes in patients with familial Mediterranean fever: systematic review and meta-analysis

OBJECTIVE

The relationship between FMF and pregnancy outcomes remains unclear. This systematic review and meta-analysis aimed to clarify this association.

METHODS

Electronic databases-PubMed, Web of Science, Cochrane, and EMBASE-were searched on 20 December 2022, using specific search terms. Case-control, cohort, and randomized clinical trial studies comparing patients with FMF and healthy controls were considered eligible. We excluded systematic reviews, meta-analyses, case series with fewer than five cases, republished articles without new findings on pregnancy outcomes, studies targeting paternal FMF, and those not published in English. The results were summarized in the form of odds ratios (ORs) and 95% CIs, using a random-effects model. This study was registered in the University hospital Medical Information Network Clinical Trials Registry (Japan) as UMIN000049827.

RESULTS

The initial electronic search identified 611 records, of which 9 were included in this meta-analysis (177 735 pregnancies, 1242 with FMF, and 176 493 healthy controls). FMF was significantly associated with increased odds of preterm deliveries (OR, 1.67; 95% CI, 1.05-2.67; I2 = 22%) and insignificantly associated with increased odds of fetal growth restriction (OR, 1.45; 95% CI, 0.90-2.34; I2 = 0%) and hypertensive disorders during pregnancy (OR, 1.28; 95% CI, 0.87-1.87; I2 = 0%).

CONCLUSION

FMF was significantly associated with preterm delivery and insignificantly associated with fetal growth restriction and hypertensive disorders. All of the included studies were observational studies. Treatment characteristics were not fully collected from the articles, and further analysis of treatments for FMF in pregnancy is still warranted.

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.

A mathematical model of Familial Mediterranean Fever predicts mechanisms controlling inflammation

BACKGROUND

Familial Mediterranean Fever (FMF) is a monogenic disease caused by gain-of-function mutations in the MEditerranean FeVer (MEFV) gene. The molecular dysregulations induced by these mutations and the associated causal mechanisms are complex and intricate.

OBJECTIVE

We sought to provide a computational model capturing the mechanistic details of biological pathways involved in FMF physiopathology and enabling the study of the patient's immune cell dynamics.

METHODS

We carried out a literature survey to identify experimental studies published from January 2000 to December 2020, and integrated its results into a molecular map and a mathematical model. Then, we studied the network of molecular interactions and the dynamic of monocytes to identify key players for inflammation phenotype in FMF patients.

RESULTS

We built a molecular map of FMF integrating in a structured manner the current knowledge regarding pathophysiological processes participating in the triggering and perpetuation of the disease flares. The mathematical model derived from the map reproduced patient's monocyte behavior, in particular its proinflammatory role via the Pyrin inflammasome activation. Network analysis and in silico experiments identified NF-κB and JAK1/TYK2 as critical to modulate IL-1β- and IL-18-mediated inflammation.

CONCLUSION

The in silico model of FMF monocyte proved its ability to reproduce in vitro observations. Considering the difficulties related to experimental settings and financial investments to test combinations of stimuli/perturbation in vitro, this model could be used to test complex hypotheses in silico, thus narrowing down the number of in vitro and ex vivo experiments to perform.

Cancer incidence in Familial Mediterranean Fever: A retrospective analysis

OBJECTIVES

Familial Mediterranean Fever (FMF) is the most common hereditary monogenic fever syndrome that is characterized by recurrent attacks of fever and polyserositis. Anti-inflammatory drugs, with colchicine being the first-line therapy, have been used in the management of FMF. This study aims to evaluate the risk of cancer in Turkish FMF patients.

METHODS

We retrospectively screened the cancer-related outcomes of our study group which consisted of Turkish FMF patients registered at our division. Cancer estimates of the Turkish population were published by the Turkish Ministry of Health in the Turkey Cancer Statistics Report 2018. Standardized incidence rates (SIR) were calculated to compare the cancer incidence observed in our study group with the expected cancer incidence of the Turkish population. Subgroup analyses were conducted on the subgroups, based on gender and usage of biological agents.

RESULTS

Our study included 1734 FMF patients, 1054 (60.8 %) of whom were females. The total follow-up was 68,784 person-years. Cancer was observed in 35 (2 %) of these patients. Turkish FMF patients had a significantly lower incidence of cancer, compared with the overall Turkish population [SIR 0.64 (95 % CI 0.46-0.89), p < 0.01]. No significant association was found between cancer and biological agent therapies in FMF patients.

CONCLUSIONS

Findings from our study indicate that the risk of cancer was decreased by 36 % in Turkish patients with FMF, compared with the outcomes of the overall Turkish population. Life-long exposure to anti-inflammatory drugs, primarily colchicine, may be the underlying reason for this outcome. Further studies are needed for the confirmation and explanation of this association.

Implications of combined NOD2 and other gene mutations in autoinflammatory diseases

NOD-like receptors (NLRs) are intracellular sensors associated with systemic autoinflammatory diseases (SAIDs). We investigated the largest monocentric cohort of patients with adult-onset SAIDs for coinheritance of low frequency and rare mutations in NOD2 and other autoinflammatory genes. Sixty-three patients underwent molecular testing for SAID gene panels after extensive clinical workups. Whole exome sequencing data from the large Atherosclerosis Risk in Communities (ARIC) study of individuals of European-American ancestry were used as control. Of 63 patients, 44 (69.8%) were found to carry combined gene variants in NOD2 and another gene (Group 1), and 19 (30.2%) were carriers only for NOD2 variants (Group 2). The genetic variant combinations in SAID patients were digenic in 66% (NOD2/MEFV, NOD2/NLRP12, NOD2/NLRP3, and NOD2/TNFRSF1A) and oligogenic in 34% of cases. These variant combinations were either absent or significantly less frequent in the control population. By phenotype-genotype correlation, approximately 40% of patients met diagnostic criteria for a specific SAID, and 60% had mixed diagnoses. There were no statistically significant differences in clinical manifestations between the two patient groups except for chest pain. Due to overlapping phenotypes and mixed genotypes, we have suggested a new term, "Mixed NLR-associated Autoinflammatory Disease ", to describe this disease scenario. Gene variant combinations are significant in patients with SAIDs primarily presenting with mixed clinical phenotypes. Our data support the proposition that immunological disease expression is modified by genetic background and environmental exposure. We provide a preliminary framework in diagnosis, management, and interpretation of the clinical scenario.

Histamine elevation in familial Mediterranean fever: A study from the Juvenile Inflammatory Rheumatism cohort

BACKGROUND

Familial Mediterranean Fever (FMF) is the most frequent monogenic autoinflammatory disease (AID). Some patients have persistent symptoms despite colchicine intake. Mast cells (MC) are innate immune cells involved in inflammatory conditions including AID. Their activation is responsible for various symptoms such as abdominal pain, bloating and pruritus.

OBJECTIVE

Our objective was to evaluate features of a systemic MC activation in FMF adult patients.

METHODS

FMF adult patients prospectively filled a MC activation survey and usual MC mediators (tryptase and histamine in whole blood, plasma and urine) were measured. They were compared with a healthy control group (HC) and a systemic mastocytosis (SM) group. When digestive biopsies were realized during follow-up, MC infiltration in digestive mucosa was analyzed in FMF, in comparison with SM, Crohn disease (CD) and normal biopsies.

RESULTS

Forty-four FMF patients, 44 HC and 44 SM patients were included. Thirty-one (70%) FMF patients had symptoms of mast cell activation, versus 14 (32%) in the HC group (p = 0.0006). Thirty (68%) FMF patients had at least one elevated MC mediator: mainly whole blood histamine, in 19 (43%) and urinary histamine, in 14 (32%), which were significantly higher than in HC subjects. MC infiltration was comparable in FMF digestive biopsies, biopsies of CD and normal biopsies but was lower than in SM biopsies.

CONCLUSION

FMF patients show frequent symptoms of MC activation and an increase of blood or urinary histamine never described before in this disease. This suggests an implication of MC and possibly basophils in FMF pathophysiology.

R202Q prevalence in clinically diagnosed Familial Mediterranean Fever patients: 9 years of data analysis from 1570 patients living Central Black Sea region, Turkey

INTRODUCTION

Familial Mediterranean fever (FMF) is an autosomal recessive disease characterized by recurrent self-limiting fever, peritonitis, arthritis, and erysipelas-like-erythema, common among ethnic groups such as Turkish, Armenian, Arab, and Jewish. The disease is caused by mutations in the MEFV gene encoding the Pyrin. This study examines the genotypes of FMF patients from Amasya, Turkey.

METHOD

According to the Tel Hashomer criteria, one thousand five hundred seventy patients (871 female, 699 male, mean age 21.2 ± 15.5 years) living in Amasya Province and the surroundings were screened for sequence variants in the entire MEFV gene. Besides, mutation types and alleles were evaluated with clinical findings.

RESULTS

MEFV mutations and polymorphisms were found in 1413 of the 1570 patients (90%). Among these patients, 5 (0.3%) were double homozygous, 152 (9.7%) were homozygous, 373 (23.8%) were double heterozygous, and 882 (56.2%) were heterozygous. The most frequent genotype was R202Q (960, 43.5%) followed by M694V (n = 412, 18.7%), E148Q (n = 321, 14.6%), and M680I (n = 200, 9.1%). The most common clinical symptoms were abdominal pain (96.4%) and fever (91.3%).

CONCLUSIONS

The fact that the R202Q genotype, which is compatible with the known FMF clinic, is frequently seen shows that it should be included in routine molecular screenings of the patients. Functional studies of the R202Q variant pyrin protein should be performed to understand FMF better. Finally, it is unclear whether the R202Q genotype might be regarded as a mutation while being approved as a polymorphism in the inFevers database.

Inflammatory Mediators of Endothelial Dysfunction

Endothelial dysfunction (ED) is characterized by imbalanced vasodilation and vasoconstriction, elevated reactive oxygen species (ROS), and inflammatory factors, as well as deficiency of nitric oxide (NO) bioavailability. It has been reported that the maintenance of endothelial cell integrity serves a significant role in human health and disease due to the involvement of the endothelium in several processes, such as regulation of vascular tone, regulation of hemostasis and thrombosis, cell adhesion, smooth muscle cell proliferation, and vascular inflammation. Inflammatory modulators/biomarkers, such as IL-1α, IL-1β, IL-6, IL-12, IL-15, IL-18, and tumor necrosis factor α, or alternative anti-inflammatory cytokine IL-10, and adhesion molecules (ICAM-1, VCAM-1), involved in atherosclerosis progression have been shown to predict cardiovascular diseases. Furthermore, several signaling pathways, such as NLRP3 inflammasome, that are associated with the inflammatory response and the disrupted H2S bioavailability are postulated to be new indicators for endothelial cell inflammation and its associated endothelial dysfunction. In this review, we summarize the knowledge of a plethora of reviews, research articles, and clinical trials concerning the key inflammatory modulators and signaling pathways in atherosclerosis due to endothelial dysfunction.

HNF4α, SP1 and c-myc are master regulators of CNS autoimmunity

Hepatocyte nuclear factor 4 α (HNF4α), a transcription factor (TF) essential for embryonic development, has been recently shown to regulate the expression of inflammatory genes. To characterize HNF4a function in immunity, we measured the effect of HNF4α antagonists on immune cell responses in vitro and in vivo. HNF4α blockade reduced immune activation in vitro and disease severity in the experimental model of multiple sclerosis (MS). Network biology studies of human immune transcriptomes unraveled HNF4α together with SP1 and c-myc as master TF regulating differential expression at all MS stages. TF expression was boosted by immune cell activation, regulated by environmental MS risk factors and higher in MS immune cells compared to controls. Administration of compounds targeting TF expression or function demonstrated non-synergic, interdependent transcriptional control of CNS autoimmunity in vitro and in vivo. Collectively, we identified a coregulatory transcriptional network sustaining neuroinflammation and representing an attractive therapeutic target for MS and other inflammatory disorders.

Transcriptional licensing is required for Pyrin inflammasome activation in human macrophages and bypassed by mutations causing familial Mediterranean fever

Pyrin is a cytosolic immune sensor that nucleates an inflammasome in response to inhibition of RhoA by bacterial virulence factors, triggering the release of inflammatory cytokines, including IL-1β. Gain-of-function mutations in the MEFV gene encoding Pyrin cause autoinflammatory disorders, such as familial Mediterranean fever (FMF) and Pyrin-associated autoinflammation with neutrophilic dermatosis (PAAND). To precisely define the role of Pyrin in pathogen detection in human immune cells, we compared initiation and regulation of the Pyrin inflammasome response in monocyte-derived macrophages (hMDM). Unlike human monocytes and murine macrophages, we determined that hMDM failed to activate Pyrin in response to known Pyrin activators Clostridioides difficile (C. difficile) toxins A or B (TcdA or TcdB), as well as the bile acid analogue BAA-473. The Pyrin inflammasome response was enabled in hMDM by prolonged priming with either LPS or type I or II interferons and required an increase in Pyrin expression. Notably, FMF mutations lifted the requirement for prolonged priming for Pyrin activation in hMDM, enabling Pyrin activation in the absence of additional inflammatory signals. Unexpectedly, in the absence of a Pyrin response, we found that TcdB activated the NLRP3 inflammasome in hMDM. These data demonstrate that regulation of Pyrin activation in hMDM diverges from monocytes and highlights its dysregulation in FMF.

Therapeutic potential of colchicine in cardiovascular medicine: a pharmacological review

Colchicine is an ancient herbal drug derived from Colchicum autumnale. It was first used to treat familial Mediterranean fever and gout. Based on its unique efficacy as an anti-inflammatory agent, colchicine has been used in the therapy of cardiovascular diseases including coronary artery disease, atherosclerosis, recurrent pericarditis, vascular restenosis, heart failure, and myocardial infarction. More recently, colchicine has also shown therapeutic efficacy in alleviating cardiovascular complications of COVID-19. COLCOT and LoDoCo2 are two milestone clinical trials that confirm the curative effect of long-term administration of colchicine in reducing the incidence of cardiovascular events in patients with coronary artery disease. There is growing interest in studying the anti-inflammatory mechanisms of colchicine. The anti-inflammatory action of colchicine is mediated mainly through inhibiting the assembly of microtubules. At the cellular level, colchicine inhibits the following: (1) endothelial cell dysfunction and inflammation; (2) smooth muscle cell proliferation and migration; (3) macrophage chemotaxis, migration, and adhesion; (4) platelet activation. At the molecular level, colchicine reduces proinflammatory cytokine release and inhibits NF-κB signaling and NLRP3 inflammasome activation. In this review, we summarize the current clinical trials with proven curative effect of colchicine in treating cardiovascular diseases. We also systematically discuss the mechanisms of colchicine action in cardiovascular therapeutics. Altogether, colchicine, a bioactive constituent from an ancient medicinal herb, exerts unique anti-inflammatory effects and prominent cardiovascular actions, and will charter a new page in cardiovascular medicine.

The Effects of Colchicine on the Histopathological Findings of Celiac Disease During Familial Mediterranean Fever Treatment

Familial mediterranean fever (FMF) and Celiac Disease (CD) are both autoinflammatory and autoimmune diseases with common clinical features affecting the gastrointestinal system. Familial mediterranean fever may coexist with CD. Inflammatory cells and cytokines are up-regulated within the intestinal mucosa of patients with CD. In this perspective, lymphocyte infiltration to the lamina propria of the small intestinal mucosa is a critical pathological sign. In the present study, we aimed to find out whether the treatment of an FMF patient with colchicine affects the pathological signs of concomitant developed CD on the same patient. We retrospectively reviewed the medical records of 147 patients with FMF who were followed up in our center between 2015 and 2020. Of the 147 patients with FMF, 3 patients also had CD. In this report, we presented these 3 cases. The findings obtained in this study suggest that pathological findings may be misinterpreted in autoimmune diseases, such as CD, when patients administer anti-inflammatory treatments, such as colchicine.

Interventions for reducing inflammation in familial Mediterranean fever

BACKGROUND

Familial Mediterranean fever (FMF), a hereditary auto-inflammatory disease, mainly affects ethnic groups living in the Mediterranean region. Early studies reported colchicine may potentially prevent FMF attacks. For people who are colchicine-resistant or intolerant, drugs such as anakinra, rilonacept, canakinumab, etanercept, infliximab or adalimumab might be beneficial. This is an update of the review last published in 2018.

OBJECTIVES

To evaluate the efficacy and safety of interventions for reducing inflammation in people with FMF.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and four Chinese databases on in August 2021. We searched clinical trials registries and references listed in relevant reports. The last search was 17 August 2021.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) of people with FMF, comparing active interventions (including colchicine, anakinra, rilonacept, canakinumab, etanercept, infliximab, adalimumab, thalidomide, tocilizumab, interferon-α and ImmunoGuard (herbal dietary supplement)) with placebo or no treatment, or comparing active drugs to each other.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology. We assessed certainty of the evidence using GRADE.

MAIN RESULTS

We included 10 RCTs with 312 participants (aged three to 53 years), including five parallel and five cross-over designed studies. Six studies used oral colchicine, one used oral ImmunoGuard, and the remaining three used rilonacept, anakinra or canakinumab as a subcutaneous injection. The duration of each study arm ranged from one to eight months. There were inadequacies in the design of the four older colchicine studies and the two studies comparing a single to a divided dose of colchicine. However, the four studies of ImmunoGuard, rilonacept, anakinra and canakinumab were generally well-designed.  We aimed to report on the number of participants experiencing an attack, the timing of attacks, the prevention of amyloid A amyloidosis, adverse drug reactions and the response of a number of biochemical markers from the acute phase of an attack; but no study reported on the prevention of amyloid A amyloidosis. Colchicine (oral) versus placebo After three months, colchicine 0.6 mg three times daily may reduce the number of people experiencing attacks (risk ratio (RR) 0.21, 95% confidence interval (CI) 0.05 to 0.95; 1 study, 10 participants; low-certainty evidence). One study (20 participants) of colchicine 0.5 mg twice daily showed there may be no difference in the number of participants experiencing attacks at two months (RR 0.78, 95% CI 0.49 to 1.23; low-certainty evidence). There may be no differences in the duration of attacks (narrative summary; very low-certainty evidence), or in the number of days between attacks: (narrative summary; very low-certainty evidence). Regarding adverse drug reactions, one study reported loose stools and frequent bowel movements and a second reported diarrhea (narrative summary; both very low-certainty evidence). There were no data on acute-phase response. Rilonacept versus placebo There is probably no difference in the number of people experiencing attacks at three months (RR 0.87, 95% CI 0.59 to 1.26; moderate-certainty evidence).  There may be no differences in the duration of attacks (narrative summary; low-certainty evidence) or in the number of days between attacks (narrative summary; low-certainty evidence). Regarding adverse drug reactions, the rilonacept study reported there may be no differences in gastrointestinal symptoms, hypertension, headache, respiratory tract infections, injection site reactions and herpes, compared to placebo (narrative summary; low-certainty evidence). The study narratively reported there may be no differences in acute-phase response indicators after three months (low-certainty evidence). ImmunoGuard versus placebo The ImmunoGuard study observed there are probably no differences in adverse effects (moderate-certainty evidence) or in acute-phase response indicators after one month of treatment (moderate-certainty evidence). No data were reported for the number of people experiencing an attack, duration of attacks or days between attacks. Anakinra versus placebo A study of anakinra given to 25 colchicine-resistant participants found there is probably no difference in the number of participants experiencing an attack at four months (RR 0.76, 95% CI 0.54 to 1.07; moderate-certainty evidence).  There were no data for duration of attacks or days between attacks. There are probably no differences between anakinra and placebo with regards to injection site reaction, headache, presyncope, dyspnea and itching (narrative summary; moderate-certainty evidence). For acute-phase response, anakinra probably reduced C-reactive protein (CRP) after four months (narrative summary; moderate-certainty evidence). Canakinumab versus placebo Canakinumab probably reduces the number of participants experiencing an attack at 16 weeks (RR 0.41, 95% CI 0.26 to 0.65; 1 study, 63 colchicine-resistant participants; moderate-certainty evidence). There were no data for the duration of attacks or days between attacks. The included study reported the number of serious adverse events per 100 patient-years was probably 42.7 with canakinumab versus 97.4 with placebo among people with colchicine-resistant FMF (moderate-certainty evidence). For acute-phase response, canakinumab probably caused a higher proportion of participants to have a CRP level of 10 mg/L or less compared to placebo (68% with canakinumab versus 6% with placebo; 1 study, 63 participants; moderate-certainty evidence). Colchicine single dose versus divided dose There is probably no difference in the duration of attacks at three months (MD -0.04 hours, 95% CI -10.91 to 10.83) or six months (MD 2.80 hours, 95% CI -5.39 to 10.99; moderate-certainty evidence). There were no data for the number of participants experiencing an attack or days between attacks. There is probably no difference in adverse events (including anorexia, nausea, diarrhea, abdominal pain, vomiting and elevated liver enzymes) between groups (narrative summary; moderate-certainty evidence). For acute-phase response, there may be no evidence of a difference between groups (narrative summary; low- to moderate-certainty evidence).

AUTHORS' CONCLUSIONS

There were limited RCTs assessing interventions for people with FMF. Based on the evidence, three times daily colchicine may reduce the number of people experiencing attacks, colchicine single dose and divided dose may not be different for children with FMF, canakinumab probably reduces the number of people experiencing attacks, and anakinra or canakinumab probably reduce CRP in colchicine-resistant participants; however, only a few RCTs contributed data for analysis. Further RCTs examining active interventions, not only colchicine, are necessary before a comprehensive conclusion regarding the efficacy and safety of interventions for reducing inflammation in FMF can be drawn.

Effects and mechanisms of SGLT2 inhibitors on the NLRP3 inflammasome, with a focus on atherosclerosis

Atherosclerosis is a lipid-driven chronic inflammatory disease that is widespread in the walls of large and medium-sized arteries. Its pathogenesis is not fully understood. The currently known pathogenesis includes activation of pro-inflammatory signaling pathways in the body, increased oxidative stress, and increased expression of cytokines/chemokines. In the innate immune response, inflammatory vesicles are an important component with the ability to promote the expression and maturation of inflammatory factors, release large amounts of inflammatory cytokines, trigger a cascade of inflammatory responses, and clear pathogens and damaged cells. Studies in the last few years have demonstrated that NLRP3 inflammatory vesicles play a crucial role in the development of atherosclerosis as well as its complications. Several studies have shown that NLRP3 binding to ligands promotes inflammasome formation, activates caspase-1, and ultimately promotes its maturation and the maturation and production of IL-1β and IL-18. IL-1β and IL-18 are considered to be the two most prominent inflammatory cytokines in the inflammasome that promote the development of atherosclerosis. SGLT2 inhibitors are novel hypoglycemic agents that also have significant antiatherosclerotic effects. However, their exact mechanism is not yet clear. This article is a review of the literature on the effects and mechanisms of SGLT2 inhibitors on the NLRP3 inflammasome, focusing on their role in antiatherosclerosis.

Clinical significance of MEFV gene variation R202Q

BACKGROUND

The aim of this study was to evaluate the phenotypic features and the clinical significance of the R202Q mutation of the MEFV gene.

METHODS

We retrospectively reviewed the medical records of Familial Mediterranean Fever patients with M694V/- and M694V/R202Q mutations. We compared the patients regarding disease severity, symptoms, age at the onset of symptoms, gender, consanguinity, and family history.

RESULTS

Twenty-one patients (9 males, 12 females) had compound heterozygote mutation (M694V/R202Q), and 37 patients (23 males, 14 females) had M694V/- mutation. The mean age of the patients at the time of diagnosis was 7.3 ± 4.3 and 9.2 ± 3.7 years. The rate of arthritis was significantly higher in patients with M694V/R202Q heterozygote mutation than those with M694V/- heterozygote mutation (76.2% vs 32.4%; p =  < 0.001). The mean severity score was higher in M694V/R202Q heterozygote group although it did not reach statistical significance (8.43 ± 1.69 vs 7.49 ± 1.50; p = 0.082). However, the rate of having a high severity score was significantly higher in the M694V/R202Q mutation group than in the other group (47.6% vs 21.6%, respectively; p = 0.039). The rate of arthritis was significantly higher in patients with M694V/R202Q heterozygote mutation than those with M694V/- heterozygote mutation (76.2% vs 32.4%; p =  < 0.001).

CONCLUSION

Our finding supports the possibility that R202Q may be pathogenic rather than a variation. We found that the R202Q mutation is associated with the inflammatory phenotype of FMF; hence, the typical clinical findings of FMF especially arthritis can be observed in patients with compound mutation including R202Q. Key Points • We found that the R202Q mutation is associated with the inflammatory phenotype of FMF • The patients with the R202Q mutation had a greater rate of arthritis symptoms.

TRIMs: selective recruitment at different steps of the NF-κB pathway-determinant of activation or resolution of inflammation

TNF-α-induced NF-κB pathway is an essential component of innate and adaptive immune pathway, and it is tightly regulated by various post-translational modifications including ubiquitination. Oscillations in NF-κB activation and temporal gene expression are emerging as critical determinants of inflammatory response, however, the regulators of unique outcomes in different patho-physiological conditions are not well understood. Tripartite Motif-containing proteins (TRIMs) are RING domain-containing E3 ligases involved in the regulation of cellular homeostasis, metabolism, cell death, inflammation, and host defence. Emerging reports suggest that TRIMs are recruited at different steps of TNF-α-induced NF-κB pathway and modulate via their E3 ligase activity. TRIMs show synergy and antagonism in the regulation of the NF-κB pathway and also regulate it in a feedback manner. TRIMs also regulate pattern recognition receptors (PRRs) mediated inflammatory pathways and may have evolved to directly regulate a specific arm of immune signalling. The review emphasizes TRIM-mediated ubiquitination and modulation of TNF-α-regulated temporal and NF-κB signaling and its possible impact on unique transcriptional and functional outcomes.

Anti-inflammatory mechanisms and research progress of colchicine in atherosclerotic therapy

Inflammatory responses play a vital role in the onset and development of atherosclerosis, and throughout the entire process of the chronic disease. The inflammatory responses in atherosclerosis are mainly mediated by the NLRP3 inflammasome and its downstream inflammatory factors. As a powerful anti‐inflammatory medicine, colchicine has a history of more than 200 years in clinical application and is the first‐choice treatment for immune diseases such as gout and familial Mediterranean fever. In atherosclerosis, colchicine can inhibit the assembly and activation of NLRP3 inflammasome via various mechanisms to effectively reduce the expression of inflammatory factors, thereby reducing the inflammation. Recent clinical trials show that a low dose of colchicine (0.5 mg per day) has a certain protective effect in stable angina patients or those with acute myocardial infarction after PCI. This article summarizes and discusses the mechanisms of colchicine in the treatment of atherosclerosis and the latest research progress.

Is neutrophilic dermatosis a manifestation of familial Mediterranean fever?

Objectives: Familial Mediterranean fever (FMF) is the most frequent monogenic autoinflammatory disease. It is associated with MEFV mutations. Its main features are recurrent episodes of fever and serositis. Patients can display dermatological manifestations such as erysipelas-like erythema, generally considered as a neutrophilic dermatosis (ND). It has been suggested that FMF can be associated with other types of ND. Our aim was to perform a systematic review of the literature to assess the link between ND and FMF.Method: A systematic review of the literature was performed using MEDLINE from 1946 to 2018. Three independent investigators identified reports of non-erysipelas-like erythema neutrophilic dermatosis (NEND) associated with FMF, selected the criteria to establish the diagnosis of FMF and ND, and evaluated the link between the two conditions. FMF-associated NEND was supported by confirmation of both diagnoses and exclusion of other causes of ND.Results: Eighteen articles were selected. Nine articles reported FMF patients with the following NEND: neutrophilic panniculitis (n = 4), Sweet syndrome (n = 6), and pyoderma gangrenosum (n = 1). None of these cases was supported by histological confirmation, fulfilled diagnostic criteria for definitive or probable FMF, or confirmed the exclusion of all the most frequent diseases associated with NEND. As a result, there is insufficient evidence to support a potential relationship between NEND and FMF.Conclusions: The association between FMF and NEND remains unclear. In FMF patients with NEND, every differential diagnosis and alternative cause of NEND should be excluded before drawing any conclusions about a potential causal relationship.

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.

Phenotypical and Functional Characterization of Neutrophils in Two Pyrin-Associated Auto-inflammatory Diseases

PURPOSE

Familial Mediterranean Fever (FMF) and Pyrin-Associated Autoinflammation with Neutrophilic Dermatosis (PAAND) are clinically distinct autoinflammatory disorders caused by mutations in the pyrin-encoding gene MEFV. We investigated the transcriptional, phenotypical, and functional characteristics of patient neutrophils to explore their potential role in FMF and PAAND pathophysiology.

METHODS

RNA sequencing was performed to discover transcriptional aberrancies. The phenotypical features, degranulation properties, and phagocytic capacity of neutrophils were assessed by flow cytometry. Production of reactive oxygen species (ROS), myeloperoxidase (MPO) release, and chemotactic responses were investigated via chemiluminescence, ELISA, and Boyden chamber assays, respectively.

RESULTS

Neutrophils from PAAND and FMF patients showed a partially overlapping, activated gene expression profile with increased expression of S100A8, S100A9, S100A12, IL-4R, CD48, F5, MMP9, and NFKB. Increased MMP9 and S100A8/A9 expression levels were accompanied by high plasma concentrations of the encoded proteins. Phenotypical analysis revealed that neutrophils from FMF patients exhibited an immature character with downregulation of chemoattractant receptors CXCR2, C5aR, and BLTR1 and increased expression of Toll-like receptor 4 (TLR4) and TLR9. PAAND neutrophils displayed an increased random, but reduced CXCL8-induced migration. A tendency for enhanced random migration was observed for FMF neutrophils. PAAND neutrophils showed a moderately but significantly enhanced phagocytic activity as opposed to neutrophils from FMF patients. Neutrophils from both patient groups showed increased MPO release and ROS production.

CONCLUSIONS

Neutrophils from patients with FMF and PAAND, carrying different mutations in the MEFV gene, share a pro-inflammatory phenotype yet demonstrate diverse features, underscoring the distinction between both diseases.

Familial Mediterranean Fever and Asthma

OBJECTIVE

To assess the association between familial Mediterranean fever and asthma.

METHODS

This study was designed as a cross-sectional study. All patients diagnosed with familial Mediterranean fever between January 1, 2000, to December 31, 2016, who were prescribed colchicine were included in the study. Controls were matched by sex, date of birth, residential socioeconomic status, and country of birth. Logistic regression models were used to determine the odds ratio for asthma in familial Mediterranean fever patients and controls.

RESULTS

A total of 7,098 familial Mediterranean fever patients who were prescribed colchicine were identified. Of them, 3,547 (50%) were females, 3,632 (51%) were of low residential socioeconomic status and 6,160 (87%) were born in Israel. Their median age at the end of follow-up was 37 years (23-54). In an unadjusted logistic regression, familial Mediterranean fever was associated with asthma (OR = 1.33, 95%CI 1.17-1.51; p < 0.001). The association persisted after adjusting for sex, socioeconomic status, and country of birth (OR = 1.33, 95%CI 1.18-1.52; p < 0.001).

CONCLUSIONS

Familial Mediterranean fever is positively associated with asthma. Further research is required to validate our results and explore possible explanations of this association. These findings cast doubt on previous studies implying familial Mediterranean fever to be a protective factor from asthma.

Transcriptional Regulation of Inflammasomes

Inflammasomes are multimolecular complexes with potent inflammatory activity. As such, their activity is tightly regulated at the transcriptional and post-transcriptional levels. In this review, we present the transcriptional regulation of inflammasome genes from sensors (e.g., NLRP3) to substrates (e.g., IL-1β). Lineage-determining transcription factors shape inflammasome responses in different cell types with profound consequences on the responsiveness to inflammasome-activating stimuli. Pro-inflammatory signals (sterile or microbial) have a key transcriptional impact on inflammasome genes, which is largely mediated by NF-κB and that translates into higher antimicrobial immune responses. Furthermore, diverse intrinsic (e.g., circadian clock, metabolites) or extrinsic (e.g., xenobiotics) signals are integrated by signal-dependent transcription factors and chromatin structure changes to modulate transcriptionally inflammasome responses. Finally, anti-inflammatory signals (e.g., IL-10) counterbalance inflammasome genes induction to limit deleterious inflammation. Transcriptional regulations thus appear as the first line of inflammasome regulation to raise the defense level in front of stress and infections but also to limit excessive or chronic inflammation.

The Yersinia Type III Secretion System as a Tool for Studying Cytosolic Innate Immune Surveillance

Microbial pathogens have evolved complex mechanisms to interface with host cells in order to evade host defenses and replicate. However, mammalian innate immune receptors detect the presence of molecules unique to the microbial world or sense the activity of virulence factors, activating antimicrobial and inflammatory pathways. We focus on how studies of the major virulence factor of one group of microbial pathogens, the type III secretion system (T3SS) of human pathogenic Yersinia, have shed light on these important innate immune responses. Yersinia are largely extracellular pathogens, yet they insert T3SS cargo into target host cells that modulate the activity of cytosolic innate immune receptors. This review covers both the host pathways that detect the Yersinia T3SS and the effector proteins used by Yersinia to manipulate innate immune signaling.

Genome sequencing unveils mutational landscape of the familial Mediterranean fever: Potential implications of IL33/ST2 signalling

Familial Mediterranean fever (FMF) is the most common auto-inflammatory disease. It is transmitted as autosomal recessive trait with mutations in MEditerranean FeVer (MEFV) gene. Despite a typical clinical expression, many patients have either a single or no mutation in MEFV. The current work is aimed to revisit the genetic landscape of FMF disease using high-coverage whole genome sequencing. In atypical patients (carrying a single or no mutation in MEFV), we revealed many rare variants in genes associated with auto-inflammatory disorders, and more interestingly, we discovered a novel variant ( a 2.1-Kb deletion) in exon 11 of IL1RL1 gene, present only in patients. To validate and screen this patient-specific variant, a tandem of allele-specific PCR and quantitative real-time PCR was performed in 184 FMF patients and 218 healthy controls and we demonstrated that the novel deletion was absent in controls and was present in more than 19% of patients. This study sheds more light on the mutational landscape of FMF. Our discovery of a disease-specific variant in IL1RL1 gene may constitute a novel genetic marker for FMF. This finding suggesting a potential role of the IL33/ST2 signalling in the disease pathogenicity highlights a new paradigm in FMF pathophysiology.

Differential mutational profiles of familial Mediterranean fever in North Africa

Familial Mediterranean fever (FMF) is a recessive autoinflammatory disease, mainly occurring in the eastern Mediterranean. In these populations, the five FMF founder mutations are differently distributed. In Algeria, the FMF-causing variants remain poorly explored. This retrospective study aims to report the mutational profile of Algerian FMF patients and to compare it with North African FMF patients. One hundred eighty-three unrelated patients clinically suspected of FMF were recruited from various Algerian hospitals (2007-2015) and tested for mutations in exon 10 of MEFV gene. Molecular analysis identified 144 mutant alleles among 87 of 183 patients (47.5%). p.M694I was the most prevalent pathogenic allele, accounting for 63.2% of mutant alleles, followed by p.M694V and p.M680I occurring with a same frequency (14.5%). Others, p.A744S (6.2%) and p.I692del (1.3%), are less frequent. Interestingly, p.M694I was the most recurrent in patients with renal AA-amyloidosis. Our results provide the first genetic data on FMF in Algeria, demonstrating the predominance of p.M694I and the absence of p.V726A, compared to other North African countries (Morocco, Tunisia, and Egypt). In conclusion, North African FMF patients display differential mutational profiles that may result from the difference in ethnic origin and the genetic heterogeneity among these populations.

Improvement of MEFV gene variants classification to aid treatment decision making in familial Mediterranean fever

Objective

FMF is an inherited autoinflammatory syndrome caused by mutations in the MEFV gene. MEFV variants are still largely classified as acvariant of uncertain significance, or with unresolved classification, posing significant challenges in FMF diagnosis. Rare Exome Variant Ensemble Learner (REVEL) is a recently developed variant metapredictor tool. To reduce the number of MEFV variants with ambiguous classification, we extracted REVEL scores for all missense variants present in the INFEVERS database, and analysed its correlation with expert-based classification and localization in the MEFV-encoded pyrin functional domains.

Methods

The data set of 216 MEFV missense variants was divided into four categories (likely benign, variant of uncertain significance, likely pathogenic and unresolved). Variants were plotted onto the pyrin protein, the distribution of REVEL scores in each category was computed and means, confidence intervals, and area under the receiver operating curve were calculated.

Results

We observed a non-random distribution of pathogenic variants along the pyrin functional domains. The REVEL scores demonstrated a good correlation with the consensus classification of the International Study Group for Systemic Autoinflammatory Diseases. Sensitivity, specificity and accuracy were calculated for different cut-off values of REVEL scores and a gene-specific-threshold of 0.298 was computed with confidence boundary limits. This cut-off value allowed us to propose a reclassification of 96 MEFV gene variants, thus reducing the variant of uncertain significance proportion from 61.6% to 17.6%.

Conclusion

The combination of available expert information with sensitive predictor tools could result in a more accurate interpretation of clinical consequences of MEFV gene variants, and to a better genetic counselling and patient management.

The pyrin inflammasome and the Yersinia effector interaction

Pyrin is a cytosolic pattern-recognition receptor that normally functions as a guard to trigger capase-1 inflammasome assembly in response to bacterial toxins and effectors that inactivate RhoA. The MEFV gene encoding human pyrin is preferentially expressed in phagocytes. Key domains in pyrin include a pyrin domain (PYD), a linker region, and a B30.2 domain. Binding of ASC to pyrin by a PYD-PYD interaction triggers inflammasome assembly. Pyrin is held in an inactive conformation by negative regulation mechanisms to avoid premature inflammasome assembly. One mechanism of negative regulation involves phosphorylation of the linker by PRK kinase which in turn is positively regulated by active RhoA. The B30.2 domain also negatively regulates pyrin. Gain of function mutations in MEFV responsible for the autoinflammatory disease Familial Mediterranean Fever (FMF) map to exon 10 encoding the B30.2 domain. Insights into pyrin regulation have come from studies of several Yersinia effectors, which are injected into phagocytes and interact with the RhoA-PRK-pyrin axis during infection. Two effectors, YopE and YopT, inactivate RhoA to disrupt phagocytic signaling. To counteract an effector-triggered immune response, a third effector, YopM, binds to and inhibits pyrin by hijacking PRK and RSK and directing linker phosphorylation. Inhibition of pyrin by YopM is required for virulence of Yersinia pestis, the agent of plague. Recent results from infection studies with human phagocytes and mice producing pyrin B30.2 FMF variants show that gain of function MEFV mutations bypass inhibition by YopM. Population genetic data suggest that MEFV mutations were selected for in individuals of Mediterranean decent during historic plague pandemics. This review discusses current concepts of pyrin regulation and its interaction with Yersinia effectors.

Optical coherence tomography-angiographic vascular densities in Familial Mediterranean Fever (FMF) Patients with M694V Mutations

Familial Mediterranean fever (FMF) is a hereditary auto-inflammatory disease with accompanying findings of amyloidosis and vasculitis. M694V is one of the most common mutations associated with amyloidosis. This study compared the macular optical coherence tomography angiography measurements in FMF patients who were genetically verified to carry the M694V mutation of the MEFV gene to those in healthy controls. The vessel densities (VDs) of superficial (SVP) and deep vascular plexus (DVP) of the retina, and choriocapillaris, foveal avascular zone (FAZ) perimetry, foveal VD 300µ around the FAZ (FD-300), acirculatory index (AI) and non-flow area were measured with  optical coherence tomography angiography (OCT-A). The FMF and control groups were matched for age and gender. Compound heterozygous pathogenic variants were excluded. Thirty-eight FMF patients with M694V mutations (28 heterozygous and 10 homozygous) and 40 healthy controls were included. The two groups were similar with the regard to age and gender (P=0.88 and P=0.49, respectively). None of the investigated parameters, including the vessel densities of the SVP and DVP, and choriocapillaris, FAZ perimetry, FD-300, AI, and non-flow area showed a statistically significant difference between the FMF and control groups. The macular vessel density measurements and FAZ parameters of FMF patients with M694V mutations do not differ from age- and sex-matched healthy controls.

Monocyte-derived dendritic cells display a highly activated phenotype and altered function in patients with familial Mediterranean fever

Dendritic cells (DCs) are sentinels of the immune system that bridge innate and adaptive immunity. By capturing antigens in peripheral tissue, processing and presenting them with concurrent expression of co‐stimulatory molecules and cytokine secretion they control and modulate immune reactions. Through pattern recognition receptors, DCs sense molecules that are associated with infection or tissue damage, frequently resulting in the formation of inflammasomes upon intracellular stimulation. The inherited autoinflammatory familial Mediterranean fever (FMF) is associated with deregulated activity of the pyrin inflammasome leading to acute inflammatory episodes. However, differentiation and function of DCs in this disease are as yet unclear. Therefore, we first determined DC subpopulation frequency in peripheral blood of a cohort of FMF patients. Joint evaluation without classification according to specific patient characteristics, such as mutational status, did not disclose significant differences compared to healthy controls. For the further examination of phenotype and function, we used immature and mature monocyte‐derived DCs (imMo‐DCs, mMo‐DCs) that were generated in vitro from FMF patients. Immunophenotypical analysis of imMo‐DCs revealed a significantly elevated expression of CD83, CD86 and human leukocyte antigen D‐related (HLA‐DR) as well as a significant down‐regulation of CD206, CD209 and glycoprotein NMB (GPNMB) in our FMF patient group. Furthermore, FMF imMo‐DCs presented a significantly higher capacity to migrate and to stimulate the proliferation of unmatched allogeneic T cells. Finally, the transition towards a more mature, and therefore activated, phenotype was additionally reinforced by the fact that peripheral blood DC populations in FMF patients exhibited significantly increased expression of the co‐stimulatory molecule CD86.

Toward targeting inflammasomes: insights into their regulation and activation

Inflammasomes are multi-component signaling complexes critical to the initiation of pyroptotic cell death in response to invading pathogens and cellular damage. A number of innate immune receptors have been reported to serve as inflammasome sensors. Activation of these sensors leads to the proteolytic activation of caspase-1, a proinflammatory caspase responsible for the cleavage of proinflammatory cytokines interleukin-1β and interleukin-18 and the effector of pyroptotic cell death, gasdermin D. Though crucial to the innate immune response to infection, dysregulation of inflammasome activation can lead to the development of inflammatory diseases, neurodegeneration, and cancer. Therefore, clinical interest in the modulation of inflammasome activation is swiftly growing. As such, it is imperative to develop a mechanistic understanding of the regulation of these complexes. In this review, we divide the regulation of inflammasome activation into three parts. We discuss the transcriptional regulation of inflammasome components and related proteins, the post-translational mechanisms of inflammasome activation, and advances in the understanding of the structural basis of inflammasome activation.

Loss of BAP1 expression is associated with an immunosuppressive microenvironment in uveal melanoma, with implications for immunotherapy development

Immunotherapy using immune checkpoint inhibitors (ICIs) induces durable responses in many metastatic cancers. Metastatic uveal melanoma (mUM), typically occurring in the liver, is one of the most refractory tumours to ICIs and has dismal outcomes. Monosomy 3 (M3), polysomy 8q, and BAP1 loss in primary uveal melanoma (pUM) are associated with poor prognoses. The presence of tumour-infiltrating lymphocytes (TILs) within pUM and surrounding mUM - and some evidence of clinical responses to adoptive TIL transfer - strongly suggests that UMs are indeed immunogenic despite their low mutational burden. The mechanisms that suppress TILs in pUM and mUM are unknown. We show that BAP1 loss is correlated with upregulation of several genes associated with suppressive immune responses, some of which build an immune suppressive axis, including HLA-DR, CD38, and CD74. Further, single-cell analysis of pUM by mass cytometry confirmed the expression of these and other markers revealing important functions of infiltrating immune cells in UM, most being regulatory CD8+ T lymphocytes and tumour-associated macrophages (TAMs). Transcriptomic analysis of hepatic mUM revealed similar immune profiles to pUM with BAP1 loss, including the expression of IDO1. At the protein level, we observed TAMs and TILs entrapped within peritumoural fibrotic areas surrounding mUM, with increased expression of IDO1, PD-L1, and β-catenin (CTNNB1), suggesting tumour-driven immune exclusion and hence the immunotherapy resistance. These findings aid the understanding of how the immune response is organised in BAP1 - mUM, which will further enable functional validation of detected biomarkers and the development of focused immunotherapeutic approaches. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Hints for Genetic and Clinical Differentiation of Adult-Onset Monogenic Autoinflammatory Diseases

Monogenic autoinflammatory diseases (mAIDs) are inherited errors of innate immunity characterized by systemic inflammation recurring with variable frequency and involving the skin, serosal membranes, synovial membranes, joints, the gastrointestinal tube, and/or the central nervous system, with reactive amyloidosis as a potential severe long-term consequence. Although individually uncommon, all mAIDs set up an emerging chapter of internal medicine: recent findings have modified our knowledge regarding mAID pathophysiology and clarified that protean inflammatory symptoms can be variably associated with periodic fevers, depicting multiple specific conditions which usually start in childhood, such as familial Mediterranean fever, tumor necrosis factor receptor-associated periodic syndrome, cryopyrin-associated periodic syndrome, and mevalonate kinase deficiency. There are no evidence-based studies to establish which potential genotype analysis is the most appropriate in adult patients with clinical phenotypes suggestive of mAIDs. This review discusses genetic and clinical hints for an ideal diagnostic approach to mAIDs in adult patients, as their early identification is essential to prompt effective treatment and improve quality of life, and also highlights the most recent developments in the diagnostic work-up for the most frequent hereditary periodic febrile syndromes worldwide.

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.

TNFR1 and TNFR2 in the Control of the Life and Death Balance of Macrophages

Macrophages stand in the first line of defense against a variety of pathogens but are also involved in the maintenance of tissue homeostasis. To fulfill their functions macrophages sense a broad range of pathogen- and damage-associated molecular patterns (PAMPs/DAMPs) by plasma membrane and intracellular pattern recognition receptors (PRRs). Intriguingly, the overwhelming majority of PPRs trigger the production of the pleiotropic cytokine tumor necrosis factor-alpha (TNF). TNF affects almost any type of cell including macrophages themselves. TNF promotes the inflammatory activity of macrophages but also controls macrophage survival and death. TNF exerts its activities by stimulation of two different types of receptors, TNF receptor-1 (TNFR1) and TNFR2, which are both expressed by macrophages. The two TNF receptor types trigger distinct and common signaling pathways that can work in an interconnected manner. Based on a brief general description of major TNF receptor-associated signaling pathways, we focus in this review on research of recent years that revealed insights into the molecular mechanisms how the TNFR1-TNFR2 signaling network controls the life and death balance of macrophages. In particular, we discuss how the TNFR1-TNFR2 signaling network is integrated into PRR signaling.

Association of pyrin mutations and autoinflammation with complex phenotype hidradenitis suppurativa: a case-control study

BACKGROUND

Hidradenitis suppurativa (HS) is a rare, debilitating neutrophilic dermatosis characterized by chronic inflammation of hair follicles. Many inflammatory conditions may accompany HS.

OBJECTIVES

To investigate the association of variants of the MEFV gene with a complex HS phenotype.

METHODS

Firstly, we identified the clinical characteristics of 119 patients with HS with a complex phenotype (Hurley stage III disease and/or additional inflammatory symptoms). Then, we searched for MEFV variants among these patients. The odds ratios (ORs) for pathogenic MEFV mutations were calculated using data from these patients with HS and 191 healthy controls.

RESULTS

The male/female ratio was higher, and the mean age of onset was earlier, in our complex HS group compared with patients with HS in general. Five of the patients with HS (4·2%) had a diagnosis of familial Mediterranean fever (FMF) with a standardized morbidity ratio of 45 [95% confidence interval (CI) 16·50-99·84, P < 0·001] when compared with the frequency of FMF in the general Turkish population. Of the patients with complex HS, 38% were positive for pathogenic variants of MEFV. The OR for carrying a pathogenic MEFV allele was 2·80 (95% CI 1·31-5·97, P < 0·001).

CONCLUSIONS

The frequency of MEFV mutations in the group of patients with complex HS was higher than that in healthy controls, suggesting that MEFV mutations may contribute to the pathogenesis of HS. Understanding the role of autoinflammation in HS is of fundamental importance for the development of novel therapies.

Inflammasome-Dependent Cytokines at the Crossroads of Health and Autoinflammatory Disease

As key regulators of both innate and adaptive immunity, it is unsurprising that the activity of interleukin (IL)-1 cytokine family members is tightly controlled by decoy receptors, antagonists, and a variety of other mechanisms. Additionally, inflammasome-mediated proteolytic maturation is a prominent and distinguishing feature of two important members of this cytokine family, IL-1β and IL-18, because their full-length gene products are biologically inert. Although vital in antimicrobial host defense, deregulated inflammasome signaling is linked with a growing number of autoimmune and autoinflammatory diseases. Here, we focus on introducing the diverse inflammasome types and discussing their causal roles in periodic fever syndromes. Therapies targeting IL-1 or IL-18 show great efficacy in some of these autoinflammatory diseases, although further understanding of the molecular mechanisms leading to unregulated production of these key cytokines is required to benefit more patients.

Increased Corneal Ectasia Risk in Patients with Familial Mediterranean Fever

PURPOSE

To evaluate the corneal tomographic parameters in patients with familial Mediterranean fever (FMF) and to compare data with those of healthy control subjects.

MATERIALS AND METHODS

Forty eyes of 40 patients with FMF (FMF group) and 35 eyes of 35 healthy subjects (control group) were included to this prospective study. All participants underwent complete ophthalmological examination and tomographic analysis with Pentacam HR. Maximum keratometry, front and back astigmatism, thinnest pachymetry, maximum anterior and posterior elevation best-fit-sphere (BFS) at the 5.0 mm zone, front and back difference elevation, final D, average and maximum pachymetric progression index, and maximum Ambrósio relational thickness parameters were noted.

RESULTS

Groups were similar in terms of age and gender (p = 0.77 and 0.35). Maximum keratometry, thinnest pachymetry, front and back astigmatism, and maximum anterior elevation BFS at the 5.0 mm values were similar between groups (p = 0.22, 0.52, 0.49, 0.29, and 0.31, respectively). Maximum posterior elevation BFS at the 5.0 mm and back difference elevation values were higher than control group in FMF group (p = 0.001 and 0.04). The mean values of final D, average and maximum pachymetric progression index were higher, and Ambrósio relational thickness was lower in FMF group compared to control group (p = 0.03, 0.002, 0.006, and 0.01, respectively).

CONCLUSIONS

FMF patients carry increased corneal ectasia risk compared to healthy subjects. The corneal tomographic characteristics and the association of keratoconus with FMF may be important in a detailed refractive surgery work-up.

TNF/TNFR axis promotes pyrin inflammasome activation and distinctly modulates pyrin inflammasomopathy

Pyrin is an inflammasome sensor that promotes caspase-1-mediated pyroptotic cell death and maturation of proinflammatory cytokines IL-1β and IL-18. Familial Mediterranean fever (FMF), an autoinflammatory disorder, is associated with mutations in the gene encoding pyrin (MEFV). FMF-knockin (FMF-KI) mice that express chimeric pyrin protein with FMF mutation (MefvV726A/V726A) exhibit an autoinflammatory disorder mediated by autoactivation of the pyrin inflammasome. Increase in the levels of TNF are observed in FMF-KI mice, and many features of FMF overlap with the autoinflammatory disorder associated with TNF receptor signaling. In this study, we assessed the contribution of TNF signaling to pyrin inflammasome activation and its consequent role in distinct FMF pathologies. TNF signaling promoted the expression of pyrin in response to multiple stimuli and was required for inflammasome activation in response to canonical pyrin stimuli and in myeloid cells from FMF-KI mice. TNF signaling promoted systemic wasting, anemia, and neutrophilia in the FMF-KI mice. Further, TNF-induced pathology was induced specifically through the TNFR1 receptor, while TNFR2-mediated signaling was distinctly protective in colitis and ankle joint inflammation. Overall, our data show that TNF is a critical modulator of pyrin expression, inflammasome activation, and pyrin-inflammasomopathy. Further, specific blockade of TNFR1 or activation of TNFR2 could provide substantial protection against FMF pathologies.

Interventions for reducing inflammation in familial Mediterranean fever

BACKGROUND

Familial Mediterranean fever, a hereditary auto-inflammatory disease, mainly affects ethnic groups living in the Mediterranean region. Early studies reported colchicine as a potential drug for preventing attacks of familial Mediterranean fever. For those people who are colchicine-resistant or intolerant, drugs such as rilonacept, anakinra, canakinumab, etanercept, infliximab, thalidomide and interferon-alpha might be beneficial. This is an updated version of the review.

OBJECTIVES

To evaluate the efficacy and safety of interventions for reducing inflammation in people with familial Mediterranean fever.

SEARCH METHODS

We used detailed search strategies to search the following databases: CENTRAL; MEDLINE; Embase; Chinese Biomedical Literature Database (CBM); China National Knowledge Infrastructure Database (CNKI); Wan Fang; and VIP. In addition, we also searched the clinical trials registries including ClinicalTrials.gov, the International Standard Randomized Controlled Trial Number Register, the WHO International Clinical Trials Registry Platform and the Chinese Clinical Trial Registry, as well as references listed in relevant reports.Date of last search: 21 August 2018.

SELECTION CRITERIA

Randomized controlled studies (RCTs) of people diagnosed with familial Mediterranean fever, comparing active interventions (including colchicine, anakinra, rilonacept, canakinumab, etanercept, infliximab, thalidomide, interferon-alpha, ImmunoGuard™ (a herbal dietary supplement) and non-steroidal anti-inflammatory drugs) with placebo or no treatment, or comparing active drugs to each other.

DATA COLLECTION AND ANALYSIS

The authors independently selected studies, extracted data and assessed risk of bias. We pooled data to present the risk ratio or mean difference with their 95% confidence intervals. We assessed overall evidence quality according to the GRADE approach.

MAIN RESULTS

We included nine RCTs with a total of 249 participants (aged three to 53 years); five were of cross-over and four of parallel design. Six studies used oral colchicine, one used oral ImmunoGuard™ and the remaining two used rilonacept or anakinra as a subcutaneous injection. The duration of each study arm ranged from one to eight months.The three studies of ImmunoGuard™, rilonacept and anakinra were generally well-designed, except for an unclear risk of detection bias in one of these. However, some inadequacy existed in the four older studies on colchicine, which had an unclear risk of selection bias, detection bias and reporting bias, and also a high risk of attrition bias and other potential bias. Neither of the two studies comparing a single to a divided dose of colchicine were adequately blinded, furthermore one study had an unclear risk of selection bias and reporting bias, a high risk of attrition bias and other potential bias.We aimed to report on the number of participants experiencing an attack, the timing of attacks, the prevention of amyloid A amyloidosis, any adverse drug reactions and the response of a number of biochemical markers from the acute phase of an attack, but data were not available for all outcomes across all comparisons.One study (15 participants) reported a significant reduction in the number of people experiencing attacks at three months with 0.6 mg colchicine three times daily (14% versus 100%), risk ratio 0.21 (95% confidence interval 0.05 to 0.95) (low-quality evidence). A further study (22 participants) of 0.5 mg colchicine twice daily showed no significant reduction in the number of participants experiencing attacks at two months (low-quality evidence). A study of rilonacept in individuals who were colchicine-resistant or intolerant (14 participants) also showed no reduction at three months (moderate-quality evidence). Likewise, a study of anakinra given to colchicine-resistant people (25 participants) showed no reduction in the number of participants experiencing an attack at four months (moderate-quality evidence).Three studies reported no significant differences in duration of attacks: one comparing colchicine to placebo (15 participants) (very low-quality evidence); one comparing single-dose colchicine to divided-dose colchicine (90 participants) (moderate-quality evidence); and one comparing rilonacept to placebo (14 participants) (low-quality evidence). Three studies reported no significant differences in the number of days between attacks: two comparing colchicine to placebo (24 participants in total) (very low-quality evidence); and one comparing rilonacept to placebo (14 participants) (low-quality evidence).No study reported on the prevention of amyloid A amyloidosis.One study of colchicine reported loose stools and frequent bowel movements (very low-quality evidence) and a second reported diarrhoea (very low-quality evidence). The rilonacept study reported no significant differences in gastrointestinal symptoms, hypertension, headache, respiratory tract infections, injection site reactions and herpes, compared to placebo (low-quality evidence). The ImmunoGuard study observed no side effects (moderate-quality evidence). The anakinra study reported no significant differences between intervention and placebo, including injection site reaction, headache, presyncope, dyspnea and itching (moderate-quality evidence). When comparing single and divided doses of colchicine, one study reported no difference in adverse events (including anorexia, nausea, diarrhoea, abdominal pain, vomiting and elevated liver enzymes) between groups (moderate-quality evidence) and the second study reported no adverse effects were detected.The rilonacept study reported no significant reduction in acute phase response indicators after three months (low-quality evidence). In the ImmunoGuard™ study, these indicators were not reduced after one month of treatment (moderate-quality evidence). The anakinra study, reported that C-reactive protein was significantly reduced after four months (moderate-quality evidence). One of the single dose versus divided dose colchicine studies reported no significant reduction in acute phase response indicators after eight months (low-quality evidence), while the second study reported no significant reduction in serum amyloid A concentration after six months (moderate-quality evidence).

AUTHORS' CONCLUSIONS

There were limited RCTs assessing interventions for people with familial Mediterranean fever. Based on the evidence, three times daily colchicine appears to reduce the number of people experiencing attacks, colchicine single dose and divided dose might not be different for children with familial Mediterranean fever and anakinra might reduce C-reactive protein in colchicine-resistant participants; however, only a few RCTs contributed data for analysis. Further RCTs examining active interventions, not only colchicine, are necessary before a comprehensive conclusion regarding the efficacy and safety of interventions for reducing inflammation in familial Mediterranean fever can be drawn.

A novel single variant in the MEFV gene causing Mediterranean fever and Behçet's disease: a case report

Background

Familial Mediterranean fever is an autoinflammatory disease of unknown etiology, characterized clinically by recurrent attacks of sudden-onset fever with arthralgia and/or thoracoabdominal pain and pathogenetically by autosomal recessive inheritance due to a mutation in the MEFV gene. Behçet’s disease is an inflammatory disease characterized by recurrent oral and genital aphthous ulcerations, uveitis, and skin lesions. Preliminarily, our literature review suggested that patients with familial Mediterranean fever who also have Behçet’s disease have only a single mutated familial Mediterranean fever gene. The MEFV gene mutation responsible for familial Mediterranean fever is probably a susceptibility factor for Behçet’s disease, particularly for patients with vascular involvement, and both disorders can occur concurrently in a patient, as in the present case.

Case presentation

A 10-year-old girl of Moroccan origin presented to our institution for genetic consultation for genetic testing of the MEFV gene. She had fever associated with abdominal and diffuse joint pain in addition to headache. These symptoms have oriented pediatricians to familial Mediterranean fever. The evolution was marked by Behçet’s syndrome symptoms. Sanger sequencing followed by complete exome sequencing analysis of the MEFV gene for the proband mutation revealed a novel variant. We conclude that the novel single variant c.2078 T > A (p.Met693Lys) could be responsible for the association of familial Mediterranean fever and Behçet’s disease.

Conclusion

To the best of our knowledge, this is the first report of a new variant in exon 10 of the MEFV gene in a Moroccan family. This novel variant should be listed in the MEFV sequence variant databases.

Inflammasome biology, molecular pathology and therapeutic implications

Inflammasomes are intracellular multiprotein signaling complexes, mainly present in myeloid cells. They commonly assemble around a cytoplasmic receptor of the nucleotide-binding leucine-rich repeat containing receptor (NLR) family, although other cytoplasmic receptors like pyrin have been shown to form inflammasomes. The nucleation of the multiprotein scaffolding platform occurs upon detection of a microbial, a danger or a homeostasis pattern by the receptor that will, most commonly, associate with the adaptor protein ASC (apoptosis-associated speck-like protein containing a CARD) through homotypic domain interactions resulting in recruitment of procaspase-1. This will lead to the autoproteolytic activation of caspase-1, which regulates the secretion of proinflammatory IL1β and IL18 cytokines and pyroptosis, a caspase-1-mediated form of cell death. Pyroptosis occurs through cleavage of Gasdermin D, a membrane pore forming protein. Recently, non-canonical inflammasomes have been described, which directly sense intracellular pathogens through caspase-4 and -5 in humans, leading to pyroptosis. Inflammasomes are important in host defense; however, a deregulated activity is associated with a number of inflammatory, immune and metabolic disorders. Furthermore, mutations in inflammasome receptor coding genes are causal for an increasing number of rare autoinflammatory diseases. Biotherapies targeting the products of inflammasome activation as well as molecules that directly or indirectly inhibit inflammasome nucleation and activation are promising therapeutic areas. This review discusses recent advances in inflammasome biology, the molecular pathology of several inflammasomes, and current therapeutic approaches in autoinflammatory diseases and in selected common multifactorial inflammasome-mediated disorders.

Update on colchicine, 2017

Colchicine is an ancient medication that is currently approved for the treatment of gout and FMF. However, colchicine has a wide range of anti-inflammatory activities, and studies indicate that it may be beneficial in a variety of other conditions. This paper reviews the evidence for the well-established use of colchicine in gout, as well as several other rheumatic diseases. In addition, we highlight the potential benefit of colchicine in cardiac disease, including coronary artery disease in patients both with and without gout.