Assessment of Circulating Microribonucleic Acids in Patients With Familial Mediterranean Fever

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.

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.

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.

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.