Microarray analysis of circulating microRNAs in familial Mediterranean fever

miR-451a and IL18 can differentiate familial Mediterranean fever patients in attack and remission periods: a prospective cross-sectional study

OBJECTIVES

Familial Mediterranean fever (FMF) is a multifaceted autoimmune disease and requires a diligent strategical approach considering disease periods and mutation subtypes. We aimed to investigate serum levels of autoimmunity-related cell-free miRNAs and inflammatory and apoptotic markers in FMF patients.

METHODS

Sixty FMF patients, of which 30 were in attack (FMF-A) and 30 were in remission (FMF-R) periods, and 25 age-, sex-, and BMI-matched healthy controls were included in our study. The expression levels of miR-26a-5p, miR-146a-5p, miR-155-2-5p, and miR-451a were analyzed with reverse-transcriptase quantitative polymerase chain reaction, and protein levels of interleukin-18 (IL18) and soluble Fas cell surface death receptor (sFAS) were measured with enzyme-linked immunosorbent assay. Serum CRP levels were analyzed by nephelometry, ferritin levels by chemiluminescence, and routine biochemical parameters by spectrophotometry. Correlation analyses were performed to seek potential associations of miRNAs with serum markers and biochemical parameters. Potential biomarkers were tested with receiver operating characteristic analysis.

RESULTS

We observed elevated serum IL18 levels but not sFAS, in FMF patients, particularly during attack period. IL18 demonstrated diagnostic value and was significantly correlated with acute-phase markers namely CRP, fibrinogen, and ferritin. Altered levels of IL18 and miR-451a could distinguish FMF patients in the attack period from the ones in remission. miR-26a-5p, miR-146a-5p, and miR-155-2-5p were downregulated in FMF patients carrying M694V mutations.

CONCLUSIONS

These findings suggest that IL18 and specific miRNAs can serve as potential biomarkers for FMF pathogenesis. Discovering promising targets for FMF-related miRNAs using mechanistic strategies will enhance our understanding of FMF disease management and therapy. Key Points • miR-451a and IL18 can serve as an indicator in distinguishing familial Mediterranean fever patients in attack and remission periods. • miR-26a-5p, miR-146a-5p, and miR-155-2-5p were dysregulated in FMF patients carrying M694V mutation.

miR-21 and cathepsin B in familial Mediterranean fever: novel findings regarding their impact on disease severity

OBJECTIVE

The limited predictive effect of genotype on familial Mediterranean fever (FMF) phenotype suggests that epigenetic factors and alternative mechanisms that may cause IL-1β release could contribute to phenotypic heterogeneity. The objective of this study was to examine the role of IL-1β levels and miR-21-5p, cathepsin B and pyrin levels, which were identified as potential factors causing IL-1β release through the use of bioinformatics tools, in the pathogenesis of FMF and their relationship with disease severity.

MATERIALS AND METHODS

50 paediatric patients with FMF and 40 healthy children were enrolled in this study. Patients were divided into subgroups according to Pras disease severity score. Serum miR-21-5p expression levels were assessed by qRT-PCR, while serum pyrin, IL-1β and cathepsin B levels were determined by ELISA.

RESULTS

Serum miR-21-5p was significantly downregulated in FMF patients compared with the control group (p<0.001), while serum pyrin, IL-1β and cathepsin B levels were markedly elevated (p<0.001 for each). Only miR-21-5p was negatively correlated with IL-1β (r=-0.855; p<0.001). In moderately severe FMF patients, miR-21-5p exhibited a statistically significant downregulation (p<0.001), whereas IL-1β and cathepsin B showed a statistically significant increase (p<0.001 and p<0.05, respectively). Furthermore, the Pras score showed a strong negative correlation (r=-0.738; p<0.001) with miR-21-5p levels. Multivariate logistic regression showed that in FMF, a one-unit decrease in miR-21 increased disease severity risk 6.76-fold, while a one-unit increase in cathepsin B raised it 1.71-fold.

CONCLUSION

This might be considered one of the mechanisms for subclinical inflammation in paediatric FMF patients through increased activation of cytokines via the downregulation of miR-21-5p. Our findings suggest that miR-21-5p and IL-1β play key roles in subclinical inflammation, and these molecules might be a potential therapeutic target.

Altered expression of miR-17 and miR-148b in pediatric familial mediterranean fever patients

Familial Mediterranean fever (FMF) is a recessively inherited autoinflammatory disorder with wide phenotypic variation that has been observed among individuals who have the same genotype. Modifying genes, epigenetic factors, or environmental factors might all have an impact on genotype-phenotype correlation in FMF. The current research aims to determine the expression levels of microRNAs (miR-148b and miR-17) in Egyptian FMF participants. We also aimed to investigate Caspase -1 gene expression to make a correlation with disease severity. The study comprised 25 clinically diagnosed FMF cases and 25 healthy subjects matched for age and sex. The molecular diagnosis of FMF cases was assessed using real-time SNP genotyping assay. MiR-148b and miR-17 expression were profiled using TaqMan assay technology. The expression level of Caspase -1 gene was also verified using qRT-PCR. MiR-17 in the studied cases was significantly upregulated compared to healthy individuals (P = 0.006), whereas miR-148b was significantly downregulated in the examined patients (P = 0.030). Moreover, statistically significant upregulation of Caspase-1 expression was also elucidated in relation to normal subjects (P = 0.033). The results obtained indicated that miR-17 and miR-148b might be potential regulatory biomarkers in FMF cases. We further hypothesized that the upregulation of Caspase-1 could hint at its significance as a future therapeutic target to alleviate the inflammatory process in these patients. Key Points • The role of miRNAs in FMF and various mechanisms involved in FMF pathogenesis has received increasing attention. • Studying the expression profiles of miR-17 and miR-148b in FMF patients revealed their potential role as regulatory biomarkers in these patients. • Significant upregulation of Caspase-1 expression in FMF cases could hint at its significance as a future therapeutic target. • Future studies on larger cohorts are warranted to clarify and better understand the role of miRNAs in the pathogenesis and severity of FMF.

Updates on the role of epigenetics in familial mediterranean fever (FMF)

Familial Mediterranean Fever (FMF) is an autosomal recessive autoinflammatory disease caused by mutations in the MEFV (MEditerranean FeVer) gene that affects people originating from the Mediterranean Sea. The high variability in severity and clinical manifestations observed not only between ethnic groups but also between and within families is mainly related to MEFV allelic heterogeneity and to some modifying genes. In addition to the genetic factors underlying FMF, the environment plays a significant role in the development and manifestation of this disease through various epigenetic mechanisms, including DNA methylation, histone modification, and noncoding RNAs. Indeed, epigenetic events have been identified as an important pathophysiological determinant of FMF and co-factors shaping the clinical picture and outcome of the disease. Therefore, it is essential to better understand the contribution of epigenetic factors to autoinflammatory diseases, namely, FMF, to improve disease prognosis and potentially develop effective targeted therapies. In this review, we highlight the latest updates on the role of epigenetics in FMF.

The Influence of Coexisting Familial Mediterranean Fever on Crohn's Disease: Data From an FMF Endemic Area

GOAL

The goal of this study was to evaluate the impact of coexisting familial Mediterranean fever (FMF) on Crohn's disease (CD) patients' phenotype and disease course in an endemic region for FMF.

BACKGROUND

CD and FMF are inflammatory diseases characterized by recurrent abdominal pain and fever attacks. The impact of coexisting FMF on CD patients' phenotype and disease course is currently unknown.

MATERIALS AND METHODS

We reviewed the medical records of 210 adult CD patients who were regularly followed up at a tertiary gastroenterology clinic between November 2006 and April 2018. The patients were divided into FMF positive (CD-FMF) and FMF negative (CD-control) groups. The severity of CD was assessed by the rate of hospitalization because of CD, the need for biological therapy, and whether surgery was performed for CD.

RESULTS

Eight (3.8%) of 210 CD patients have concomitant FMF, which is 35 to 40 times higher than expected in an endemic region for FMF. Baseline demographic parameters, location/behavior of the CD, and initial therapeutic regimens were similar between the 2 groups. The prevalence of peripheral arthritis was significantly higher in CD-FMF group (37.5% vs. 10.4%, respectively, P =0.04). A significantly greater proportion of the CD-FMF patients had received biological therapy (50% vs. 11.9%; P =0.012). Steroid dependence and CD-related hospitalization rates in the CD-FMF group were relatively higher but were not statistically significant (37.5% vs. 15.3 and 62.5% vs. 41.1%).

CONCLUSIONS

Our findings indicate that the disease course of CD tends to be more severe in patients with coexisting FMF.

Familial Mediterranean fever and microRNAs

Familial Mediterranean fever (FMF) is an inherited disorder caused by the gain of function mutations in MEFV (MEditerranean FeVer) gene loci. FMF affects more than 100,000 people worldwide and generally seen in the eastern Mediterranean region and causes the lifelong diseases which have a significant effect on the patient's life quality and health systems. The identification of low penetrant or heterozygous MEFV gene mutations in clinically diagnosed FMF patients was considered that epigenetic or environmental factors may display a role in FMF pathogenesis. Epigenetics might be defined as heritable changes that affect gene expression without any changes in the genome. MicroRNAs (miRNAs) are the main group of small noncoding RNAs, and an important element of epigenetic mechanisms and their discoveries revolutionized our knowledge about biological processes, such as malignant, infectious and autoimmune mechanisms, and contributed to the development of the epigenetic areas. In this review, the studies focusing on the roles of miRNAs in FMF pathogenesis in the last decades were examined and the importance of miRNAs as therapeutic agents which are promising for diagnosis and treatment was discussed.

How to Build a Fire: The Genetics of Autoinflammatory Diseases

Systemic autoinflammatory diseases (SAIDs) are a heterogeneous group of disorders caused by excess activation of the innate immune system in an antigen-independent manner. Starting with the discovery of the causal gene for familial Mediterranean fever, more than 50 monogenic SAIDs have been described. These discoveries, paired with advances in immunology and genomics, have allowed our understanding of these diseases to improve drastically in the last decade. The genetic causes of SAIDs are complex and include both germline and somatic pathogenic variants that affect various inflammatory signaling pathways. We provide an overview of the acquired SAIDs from a genetic perspective and summarize the clinical phenotypes and mechanism(s) of inflammation, aiming to provide a comprehensive understanding of the pathogenesis of autoinflammatory diseases.

Dysregulation of miRNA-30e-3p targeting IL-1β in an international cohort of systemic autoinflammatory disease patients

Autoinflammation is the standard mechanism seen in systemic autoinflammatory disease (SAID) patients. This study aimed to investigate the effect of a candidate miRNA, miR-30e-3p, which was identified in our previous study, on the autoinflammation phenotype seen in SAID patients and to analyze its expression in a larger group of European SAID patients. We examined the potential anti-inflammatory effect of miR-30e-3p, which we had defined as one of the differentially expressed miRNAs in microarray analysis involved in inflammation-related pathways. This study validated our previous microarray results of miR-30e-3p in a cohort involving European SAID patients. We performed cell culture transfection assays for miR-30e-3p. Then, in transfected cells, we analyzed expression levels of pro-inflammatory genes; IL-1β, TNF-α, TGF-β, and MEFV. We also performed functional experiments, caspase-1 activation by fluorometric assay kit, apoptosis assay by flow cytometry, and cell migration assays by wound healing and filter system to understand the possible effect of miR-30e-3p on inflammation. Following these functional assays, 3'UTR luciferase activity assay and western blotting were carried out to identify the target gene of the aforementioned miRNA. MiR-30e-3p was decreased in severe European SAID patients like the Turkish patients. The functional assays associated with inflammation suggested that miR-30e-3p has an anti-inflammatory effect. 3'UTR luciferase activity assay demonstrated that miR-30e-3p directly binds to interleukin-1-beta (IL-1β), one of the critical molecules of inflammatory pathways, and reduces both RNA and protein levels of IL-1β. miR-30e-3p, which has been associated with IL-1β, a principal component of inflammation, might be of potential diagnostic and therapeutic value for SAIDs. KEY MESSAGES: miR-30e-3p, which targets IL-1β, could have a role in the pathogenesis of SAID patients. miR-30e-3p has a role in regulating inflammatory pathways like migration, caspase-1 activation. miR-30e-3p has the potential to be used for future diagnostic and therapeutic approaches.

MicroRNAs in inflammasomopathies

microRNAs (miRNAs) are small non-coding RNA sequences that negatively regulate the expression of protein-encoding genes at the post-transcriptional level. They play a role in the regulation of inflammatory responses by controlling the proliferation and activation of immune cells and their expression is disrupted in several immune-mediated inflammatory disorders. Among these, autoinflammatory diseases (AID) are a group of rare hereditary disorders caused by abnormal activation of the innate immune system and characterized by recurrent fevers. Major groups of AID are inflammasomopathies, which are associated with hereditary defects in the activation of inflammasomes, cytosolic multiprotein signaling complexes regulating IL-1 family cytokine maturation and pyroptosis. The study of the role of miRNAs in AID is only recently emerging and remains scarce in inflammasomopathies. In this review, we describe the AID and inflammasomopathies, and the current knowledge on the role of miRNAs in disease processes.

Recurrent pain attacks during romiplostim treatment in a patient with ITP carrying a heterozygous MEFV mutation

We report a case of recurrent pain attacks during romiplostim treatment in a woman with immune thrombocytopenia carrying a heterozygous MEFV mutation. Five months after starting treatment with romiplostim for immune thrombocytopenia, she was diagnosed with idiopathic pericarditis. She was switched to eltrombopag, but thrombocytopenia did not improve. Romiplostim was restarted 7 months later, although she then developed recurrent right hypochondrial pain. The pain typically occurred three days after the romiplostim injection and resolved two days later. She had never experienced such recurrent pain before starting romiplostim or after discontinuing it. Genetic analysis showed that she carried a heterozygous R202Q alteration in exon 2 of the MEFV gene. MEFV mutation is known to cause familial Mediterranean fever, which is characterized by symptoms such as recurrent fever, abdominal and chest pain, arthritis, and pericarditis. This case suggests that romiplostim has the potential to trigger recurrent pain/inflammation attacks in individuals with systemic inflammatory abnormalities.

The Assessment of Selected miRNA Profile in Familial Mediterranean Fever

Familial Mediterranean fever (FMF) is the most prevalent autoinflammatory disease. Typical findings are recurrent fever attacks with serositis, skin rash, and synovitis. FMF is caused by mutations in the MEFV gene, encoding pyrin protein. Pyrin functions in innate immunity and triggers inflammation via inflammatory mediators' production and acts as the primary regulatory component of the inflammasome. On the other hand, various miRNAs play crucial roles in the pathogenesis of different types of cancers and immune-related and neurodegenerative diseases. However, their association with FMF is still unclear. Therefore, in this study, we assessed the roles of selected thirteen miRNAs associated with immune functions. We recruited genetically diagnosed 28 FMF patients and 28 healthy individuals. The expression profiling of the miRNAs was determined by qRT-PCR and normalized to SNORD61. Our analysis revealed that miR-34a-5p, miR-142-3p, miR-216a-5p, miR-340-5p, miR-429, and miR-582-5p were upregulated, whereas miR-107, miR-569, and miR-1304-5p were downregulated in the FMF patients. Among them, miR-107 was found to be the most remarkable in M694V homozygous mutants compared to other homozygous mutants. During clinical follow-up of the patients with M694V mutation, which is closely related to amyloidosis, evaluation of mir-107 expression might be crucial and suggestive. Our results showed that miRNAs might serve a function in the pathogenesis of FMF. Further studies may provide novel and effective diagnostic and therapeutic agents that target examined miRNAs. Targeting miRNAs in FMF seems to be promising and may yield a new generation of rational therapeutics and diagnostic or monitoring tools enabling FMF treatment.

Non-Coding RNAs: Master Regulators of Inflammasomes in Inflammatory Diseases

Emerging data indicates that non-coding RNAs (ncRNAs) represent more than just “junk sequences” of the genome and have been found to be involved in multiple diseases by regulating various biological process, including the activation of inflammasomes. As an important aspect of innate immunity, inflammasomes are large immune multiprotein complexes that tightly regulate the production of pro-inflammatory cytokines and mediate pyroptosis; the activation of the inflammasomes is a vital biological process in inflammatory diseases. Recent studies have emphasized the function of ncRNAs in the fine control of inflammasomes activation either by directly targeting components of the inflammasomes or by controlling the activity of various factors that control the activation of inflammasomes; consequently, ncRNAs may represent potential therapeutic targets for inflammatory diseases. Understanding the precise role of ncRNAs in controlling the activation of inflammasomes will help us to design targeted therapies for multiple inflammatory diseases. In this review, we summarize the regulatory role and therapeutic potential of ncRNAs in the activation of inflammasomes by focusing on a range of inflammatory diseases, including microbial infection, sterile inflammatory diseases, and fibrosis-related diseases. Our goal is to provide new ideas and perspectives for future research.

miRNAs as attractive diagnostic and therapeutic targets for Familial Mediterranean Fever

Familial Mediterranean Fever (FMF) is a hereditary early-onset disease that causes periodical fever attack, excessive release of IL-1β, serositis, arthritis and peritonitis. Genetic analyses conducted on FMF patients (mutated and non-mutated) have highlighted that additional contributing factors such as epigenetics and environment play a role in clinical manifestations of FMF. Recently researchers report that microRNAs (miRNAs), implicated in epigenetic mechanisms, may contribute to the pathogenesis of FMF. miRNAs, a member of the captivating noncoding RNA family, are the single-strand transcripts that work in physiological and pathophysiological processes by regulating target gene expression. Recent studies have shown that miRNAs are associated with various mechanisms involved in the pathogenesis of FMF, such as apoptosis, inflammation and autophagy. Moreover, these miRNAs molecules might have potential use in treatment, therapeutic response monitoring and the diagnosis of subtypes of the disease in the future. Motivated by these potential benefits (diagnostic and therapeutic) of miRNAs, we focus on recent advances of clinical significances and potential action mechanisms of miRNAs in FMF pathogenesis and discuss their potential use for FMF.

Familial Mediterranean fever-related miR-197-3p targets IL1R1 gene and modulates inflammation in monocytes and synovial fibroblasts

Familial Mediterranean fever (FMF); is an autosomal recessively inherited autoinflammatory disease caused by the mutations in the Mediterranean Fever (MEFV) gene. Recent studies have shown that epigenetic control mechanisms, particularly non-coding RNAs, may play a role in the pathogenesis of autoinflammation. microRNAs (miRNAs) are small non-coding RNAs that play critical roles in regulating host gene expression at the post-transcriptional level. The phenotypic heterogeneity of FMF disease suggests that FMF may not be a monogenic disease, suggesting that epigenetic factors may affect phenotypic presentation. Here we examined the potential anti-inflammatory effect of miR-197-3p, which is a differentially expressed miRNA in FMF patients, by using inflammation related functional assays. We monitored gene expression levels of important cytokines, as well as performed functional studies on IL-1β secretion, caspase-1 activation, apoptosis assay, and cell migration assay. These experiments were used to evaluate the different stages of inflammation following pre-miR-197 transfection. Anti-miR-197 transfections were performed to test the opposite effect. 3′UTR luciferase activity assay was used for target gene studies. Our results obtained by inflammation-related functional assays demonstrated an anti-inflammatory effect of miR-197-3p in different cell types (synovial fibroblasts, monocytes, macrophages). 3′UTR luciferase activity assay showed that miR-197-3p directly binds to the interleukin-1beta (IL-1β) receptor, type I (IL1R1) gene, which is one of the key molecules of the inflammatory pathways. This study may contribute to understand the role of miR-197-3p in autoinflammation process. Defining the critical miRNAs may guide the medical community in a more personalized medicine in autoinflammatory diseases.

Familial Mediterranean fever, from pathogenesis to treatment: a contemporary review

Familial Mediterranean fever (FMF) (OMIM #249100) is the most common hereditary autoinflammatory disease in the world. FMF is caused by gain of function mutations of MEFV gene which encodes an immune regulatory protein, pyrin. Over the last few years, we have witnessed several new developments in the pathogenesis, genetic testing, diagnosis, comorbidities, disease related damage and treatment approaches to FMF. Elucidation of some of the pathogenic mechanisms has led to the discovery of pathways involved in inflammatory, metabolic, cardiovascular and degenerative diseases. The use of next generation sequencing in FMF has revealed many new gene variants whose clinical significance may be clarified by developing functional assays and biomarkers. Clinically, although FMF is considered an episodic disease characterized by brief attacks, recent systematic studies have defined several associated chronic inflammatory conditions. Colchicine is the mainstay of FMF treatment, and interleukin (IL)-1 antagonists are the treatment of choice in refractory or intolerant cases. Experience of IL-1 antagonists, anakinra and canakinumab, is now available in thousands of colchicine resistant or intolerant FMF patients. In this contemporary review, we surveyed current FMF knowledge in the light of these recent advances.

Systemic autoinflammatory diseases

Systemic autoinflammatory diseases (SAIDs) are a growing group of disorders caused by a dysregulation of the innate immune system leading to episodes of systemic inflammation. In 1997, MEFV was the first gene identified as disease causing for Familial Mediterranean Fever, the most common hereditary SAID. In most cases, autoinflammatory diseases have a strong genetic background with mutations in single genes. Since 1997 more than 30 new genes associated with autoinflammatory diseases have been identified, affecting different parts of the innate immune system. Nevertheless, for at least 40-60% of patients with phenotypes typical for SAIDs, a distinct diagnosis cannot be met, leading to undefined SAIDs (uSAIDs). However, SAIDs can also be of polygenic or multifactorial origin, with environmental influence modulating the phenotype. The implementation of a disease continuum model combining the adaptive and the innate immune system with autoinflammatory and autoimmune diseases shows the complexity of SAIDs and the importance of new methods to elucidate molecular changes and causative factors in SAIDs. Diagnosis is often based on clinical presentation and genetic testing. The timeline from onset to diagnosis takes up to 7.3 years, highlighting the indisputable need to identify new treatment and diagnostic targets. Recently, other factors are under investigation as additional contributors to the pathogenesis of SAIDs. This review gives an overview of pathogenesis and etiology of SAIDs, and summarizes recent diagnosis and treatment options.

Current and future advances in genetic testing in systemic autoinflammatory diseases

Systemic autoinflammatory diseases (SAIDs) are a group of inflammatory disorders caused by dysregulation in the innate immune system that leads to enhanced immune responses. The clinical diagnosis of SAIDs can be difficult since individually these are rare diseases with considerable phenotypic overlap. Most SAIDs have a strong genetic background, but environmental and epigenetic influences can modulate the clinical phenotype. Molecular diagnosis has become essential for confirmation of clinical diagnosis. To date there are over 30 genes and a variety of modes of inheritance that have been associated with monogenic SAIDs. Mutations in the same gene can lead to very distinct phenotypes and can have different inheritance patterns. In addition, somatic mutations have been reported in several of these conditions. New genetic testing methods and databases are being developed to facilitate the molecular diagnosis of SAIDs, which is of major importance for treatment, prognosis and genetic counselling. The aim of this review is to summarize the latest advances in genetic testing for SAIDs and discuss potential obstacles that might arise during the molecular diagnosis of SAIDs.

Altered expression of apoptosis-related, circulating cell-free miRNAs in children with familial Mediterranean fever: a cross-sectional study

OBJECTIVES

Familial Mediterranean Fever (FMF) is the most common hereditary autoinflammatory disorder characterized by recurrent fever and serositis episodes. Identification of low penetrant or heterozygous MEFV mutations in clinically diagnosed FMF patients did raise a concern on whether epigenetic or environmental factors play an additional role in FMF pathogenesis. We aimed to investigate the expression profile of apoptosis-related miRNAs in FMF and their influence on clinical manifestations in the present study.

METHOD

191 pediatric FMF patients and 31 healthy children included in the study. Expressions of 33 apoptosis-related, circulating cell-free miRNAs were evaluated by a quantitative polymerase chain reaction, statistically calculated within ΔΔCt values and fold changes were evaluated by Welch T test, in which p < 0.05 were considered to be significant.

RESULTS

Nineteen miRNAs, including let-7a-5p, let-7c, let-7 g-5p, miR-15b-5p, miR-16-5p, miR-17-5p, miR-23a-3p, miR-24-3p, miR-25-3p, miR-26a-5p, miR-26b-5p, miR-27a-3p, miR-29c-3p, miR-30a-5p, miR-30d-5p, miR-30e-5p, miR-106b-5p, miR-146a-5p, and miR-195-5p, were found down-regulated; miR-15a-5p, miR-29b-3p, miR-181a-5p, miR-181b-5p, miR-181c-5p, miR-214-3p, and miR-365a-3p were up-regulated in FMF patients. In detail, these miRNAs were similar among FMF patients in terms of genotype, colchicine response, and having an inflammatory attack during analysis.

CONCLUSION

We found that 26 apoptosis-related circulating miRNAs were deregulated in children with FMF. Thus, we speculate that these miRNAs have a role in FMF pathogenesis via apoptotic mechanisms.

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.

Assessment of Circulating Microribonucleic Acids in Patients With Familial Mediterranean Fever

Objectives

This study aims to evaluate the plasma expression of microribonucleic acids (miRNAs) that may be associated with the pathogenesis of familial Mediterranean fever (FMF).

Patients and methods

Thirty patients with FMF (18 males, 12 females; mean age 9.1±4.7 years; range, 3 to 15.5 years) and 30 age- and sex-matched healthy children (18 males, 12 females; mean age 9.5±4.6 years; range, 4 to 16.5 years) were included in this study. The plasma levels of four candidate miRNAs (miRNA-16, miRNA-155, miRNA-204 and miRNA-451) were measured in all subjects. The plasma levels of miRNAs were analyzed with real- time polymerase chain reaction in attack and remission periods of patients and healthy controls (HCs).

Results

Plasma miRNA-204 levels of FMF patients were decreased 6.5 fold in remission period compared to HCs (p<0.001). This decrease was more prominent in M694V mutation carriers. Plasma miRNA-155 levels of FMF patients were lower in remission period (p=0.03).

Conclusion

Our findings showed significant alterations in the plasma expression of miRNA-155 and miRNA-204 in FMF patients compared to HCs. Our data suggest that miRNA-155 and miRNA-204 may be related to the pathogenesis of FMF. Further comprehensive and functional researches may help to clarify the role of miRNAs in FMF and elucidate the pathogenesis of the disease.

Potential of miRNAs to predict and treat inflammation from the perspective of Familial Mediterranean Fever

AIM

microRNAs (miRNAs) are small noncoding RNAs that play critical roles in physiological networks by regulating host genome expression at the post-transcriptional level. miRNAs are known to be key regulators of various biological processes in different types of immune cells, and they are known to regulate immunological functions. Differential expression of miRNAs has been documented in several diseases, including autoinflammatory and autoimmune diseases. This review aimed to focus on miRNAs and their association with autoimmune and autoinflammatory diseases.

METHODS

All related literature was screened from PubMed, and we discussed the possible role of miRNAs in disease prediction and usage as therapeutic agents from the perspective of Familial Mediterranean Fever (FMF).

CONCLUSIONS

FMF is an inherited autosomal recessive autoinflammatory disease caused by mutations in the MEditerranean FeVer (MEFV) gene, which encodes the protein pyrin. Recent studies have demonstrated that miRNAs may be effective in the pathogenesis of FMF and offer a potential explanation for phenotypic heterogeneity. Further understanding of the role of miRNAs in the pathogenesis of these diseases may help to identify molecular diagnostic markers, which may be important for the differential diagnosis of autoinflammatory diseases. Studies have shown that in the near future, traditional therapies in autoinflammatory diseases may be replaced with novel effective, miRNA-based therapies, such as the delivery of miRNA mimics or antagonists. These approaches may be important for predictive, preventive, and personalized medicine.

Familial Mediterranean fever: overview of pathogenesis, clinical features and management

Familial Mediterranean fever (FMF) is the most common monogenic autoinflammatory disease, and is characterized by recurrent attacks of fever and polyserositis. It is associated with mutations in the MEFV gene encoding pyrin, which result in inflammasome activation and the uncontrolled production of IL-1β. FMF mainly affects individuals originating from the Mediterranean basin; however, a Japanese nationwide survey demonstrated that FMF is not uncommon in Japan. The survey also indicated that Japanese FMF patients are clinically or genetically distinct from Mediterranean FMF patients, suggesting a genotype-phenotype correlation. In Japanese patients with FMF, MEFV exon 10 mutations are associated with the more typical FMF phenotype. Conversely, Japanese FMF patients with mutations in MEFV exons 2 or 3 present with an atypical FMF phenotype. Colchicine is the mainstay of FMF treatment, and its regular use prevents febrile attacks and decreases the long-term risk of AA amyloidosis. However, a minority of FMF patients are colchicine-resistant, and anti-IL-1 treatment has proven beneficial in suppressing inflammation in these patients. Although Japanese FMF patients may develop less severe disease compared with Mediterranean FMF patients, they should nevertheless be treated early to prevent recurrent attacks and the subsequent development of AA amyloidosis.

Analysis of microRNAs in familial Mediterranean fever

OBJECTIVES

Although Familial Mediterranean fever (FMF) is categorized as autosomal recessive, frequent exceptions to this model exist and therefore we aimed to search epigenetic modifications in this disease.

METHODS

Ten M694V homozygous FMF patients (the most severe phenotype) were recruited for this study. Patients with inflammatory flare were excluded. Total RNA was extracted from peripheral blood, and microRNA expression profiled using NanoString nCounter technology. These patients were compared to 10 healthy age- and sex-matched controls.

RESULTS

Seven hundred nighty-eight mature human miRNAs were probed, 103 of which had expression levels above the negative control probes. Seven miRNAs showed significant differences in expression in samples from FMF patients compared to healthy controls: four miRNAs were upregulated (miR-144-3p, miR-21-5p, miR-4454, and miR-451a), and three were downregulated (miR-107, let-7d-5p, and miR-148b-3p).

CONCLUSION

In this pilot study, we identified epigenetic modifications in clinically quiescent FMF patients. More studies are required for exploration of their contribution to FMF pathogenesis and their potential role as clinical biomarkers.