Polymorphisms of interferon-γ, interleukin-10, and interleukin-12 genes in myasthenia gravis

Cytokines Single Nucleotide Polymorphisms (SNPs) Association With Myasthenia Gravis (MG) In Algerian Patients: A Case-Control Study On A Small Group

ABSTRACT

Myasthenia gravis (MG) is an autoimmune disease of multifactorial etiology in which genetic factors and cytokines seem to play an important role. The aim of this study was to investigate potential associations of cytokines single nucleotide polymorphisms (SNPs) and MG in Algerian patients. We performed a case-control study that included 27 patients and 74 healthy subjects. Cytokines SNPs genotyping was performed by the polymerase chain reaction sequence-specific primers (PCR-SSP) method. Our results showed that the TNF-α -308G/A (P < 0.005) and TGF-β1 +869T/T (P < 0.05) genotypes were more frequent among patients with MG compared with healthy individuals, whereas TNF-α -308G/G (P < 0.0001), TGF-β1 +869T/C (P < 0.05), and IFN-γ +874A/A (P < 0.05) were less frequent. Our results also showed that IL-10 and IL-6 SNPs did not show any significant difference in distribution between MG patients and healthy individuals. Our observations support the hypothesis that implicates genetic variants of certain cytokines in MG. However, ours results should be replicated with a larger sample size. In addition, the precise underlying processes remain to be clarified.

HIGHLIGHTS

TNF-α -308G/A and TGF-β1 +869T/C genotypes predispose to MG.IFN-γ +874A/A genotype protects against MG.IL-6 -174C/G SNP is not associated with MG.

Long Non-Coding RNAs in the Cell Fate Determination of Neoplastic Thymic Epithelial Cells

Thymic Epithelial Tumors (TETs) arise from epithelial cells of the thymus and are very rare neoplasms comprising Thymoma, Thymic carcinoma, and Thymic Neuroendocrine tumors that still require in-depth molecular characterization. Long non-coding RNAs (lncRNAs) are emerging as relevant gene expression modulators involved in the deregulation of several networks in almost all types of human cancer, including TETs. LncRNAs act at different control levels in the regulation of gene expression, from transcription to translation, and modulate several pathways relevant to cell fate determination under normal and pathological conditions. The activity of lncRNAs is strongly dependent on their expression, localization, and post-transcriptional modifications. Starting from our recently published studies, this review focuses on the involvement of lncRNAs in the acquisition of malignant traits by neoplastic thymic epithelial cells, and describes the possible use of these molecules as targets for the design of novel therapeutic approaches specific for TET. Furthermore, the involvement of lncRNAs in myasthenia gravis (MG)-related thymoma, which is still under investigation, is discussed.

NKT and NKT-like Cells in Autoimmune Neuroinflammatory Diseases-Multiple Sclerosis, Myasthenia Gravis and Guillain-Barre Syndrome

NKT cells comprise three subsets-type I (invariant, iNKT), type II, and NKT-like cells, of which iNKT cells are the most studied subset. They are capable of rapid cytokine production after the initial stimulus, thus they may be important for polarisation of Th cells. Due to this, they may be an important cell subset in autoimmune diseases. In the current review, we are summarising results of NKT-oriented studies in major neurological autoimmune diseases-multiple sclerosis, myasthenia gravis, and Guillain-Barre syndrome and their corresponding animal models.

Whole-exome sequencing reveals a rare interferon gamma receptor 1 mutation associated with myasthenia gravis

Our study is aimed to explore the underlying genetic basis of myasthenia gravis. We collected a Chinese pedigree with myasthenia gravis, and whole-exome sequencing was performed on the two affected siblings and their parents. The candidate pathogenic gene was identified by bioinformatics filtering, which was further verified by Sanger sequencing. The homozygous mutation c.G40A (p.V14M) in interferon gamma receptor 1was identified. Moreover, the mutation was also detected in 3 cases of 44 sporadic myasthenia gravis patients. The p.V14M substitution in interferon gamma receptor 1 may affect the signal peptide function and the translocation on cell membrane, which could disrupt the binding of the ligand of interferon gamma and antibody production, contributing to myasthenia gravis susceptibility. We discovered that a rare variant c.G40A in interferon gamma receptor 1 potentially contributes to the myasthenia gravis pathogenesis. Further functional studies are needed to confirm the effect of the interferon gamma receptor 1 on the myasthenia gravis phenotype.

Systems biology of myasthenia gravis, integration of aberrant lncRNA and mRNA expression changes

Background

A novel class of transcripts, long non-coding RNAs (lncRNAs), has recently emerged as a key player in several biological processes, and important roles for these molecules have been reported in a number of complex human diseases, such as autoimmune diseases, neurological disorders, and various cancers. However, the aberrant lncRNAs implicated in myasthenia gravis (MG) remain unknown. The aim of the present study was to explore the abnormal expression of lncRNAs in peripheral blood mononuclear cells (PBMCs) and examine mRNA regulatory relationship networks among MG patients with or without thymoma.

Methods

Microarray assays were performed, and the outstanding differences between lncRNAs or mRNA expression were verified through RT-PCR. The lncRNAs functions were annotated for the target genes using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) biological pathway. The potential regulatory relationships between the lncRNAs and target genes were analyzed using the ‘cis’ and ‘trans’ model. Outstanding lncRNAs were organized to generate a TF-lncRNA-gene network using Cytoscape software.

Results

The lncRNA and mRNA expression profile analysis revealed subsets of differentially expressed genes in MG patients with or without thymoma. A total of 12 outstanding dysregulated expression lncRNAs, such as lncRNA oebiotech_11933, were verified through real-time PCR. Several GO terms including the cellular response to interferon-γ, platelet degranulation, chemokine receptor binding and cytokine interactions were very important in MG pathogenesis. The chromosome locations of some lncRNAs and associated co-expression genes were demonstrated using ‘cis’ analysis. The results of the ‘trans’ analysis revealed that some TFs (i.e., CTCF, TAF1and MYC) regulate lncRNA and gene expression. The outstanding lncRNAs in each group were implicated in the regulation of the TF-lncRNA-target gene network.

Conclusion

The results of the present study provide a perspective on lncRNA expression in MG. We identify a subset of aberrant lncRNAs and mRNAs as potential biomarkers for the diagnosis of MG. The GO and KEGG pathway analysis provides an annotation to determine the functions of these lncRNAs. The results of the ‘cis’ and ‘trans’ analyses provide information concerning the modular regulation of lncRNAs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12920-015-0087-z) contains supplementary material, which is available to authorized users.

Myasthenia Gravis: paradox versus paradigm in autoimmunity

Myasthenia Gravis (MG) is a paradigm of organ-specific autoimmune disease (AID). It is mediated by antibodies that target the neuromuscular junction. The purpose of this review is to place MG in the general context of autoimmunity, to summarize the common mechanisms between MG and other AIDs, and to describe the specific mechanisms of MG. We have chosen the most common organ-specific AIDs to compare with MG: type 1 diabetes mellitus (T1DM), autoimmune thyroid diseases (AITD), multiple sclerosis (MS), some systemic AIDs (systemic lupus erythematous (SLE), rheumatoid arthritis (RA), Sjogren's syndrome (SS)), as well as inflammatory diseases of the gut and liver (celiac disease (CeD), Crohn's disease (CD), and primary biliary cirrhosis (PBC)). Several features are similar between all AIDs, suggesting that common pathogenic mechanisms lead to their development. In this review, we address the predisposing factors (genetic, epigenetic, hormones, vitamin D, microbiota), the triggering components (infections, drugs) and their interactions with the immune system [1,2]. The dysregulation of the immune system is detailed and includes the role of B cells, Treg cells, Th17 and cytokines. We particularly focused on the role of TNF-α and interferon type I whose role in MG is very analogous to that in several other AIDS. The implication of AIRE, a key factor in central tolerance is also discussed. Finally, if MG is a prototype of AIDS, it has a clear specificity compared to the other AIDS, by the fact that the target organ, the muscle, is not the site of immune infiltration and B cell expansion, but exclusively that of antibody-mediated pathogenic mechanisms. By contrast, the thymus in the early onset subtype frequently undergoes tissue remodeling, resulting in the development of ectopic germinal centers surrounded by high endothelial venules (HEV), as observed in the target organs of many other AIDs.

Research advancement in immunopathogenesis of myasthenia gravis

Myasthenia gravis (MG) is an autoimmune neuromuscular junction disease mediated by antibodies against the acetylcholine receptor (AChR). The etiology and immunopathogenesis of MG remain unclear. Recent research has shown the involvement of autoantibodies, lymphocytes, cytokines and chemokines, in the pathogenesis of MG. Systematic factors are also demonstrated, such as inheritance and endocrine. This review indicates the research development in immunopathogenesis of MG.

A novel functional polymorphism, 16974 A/C, in the interleukin-12-3' untranslated region is associated with risk of glioma

Genetic factors are important in the development of glioma. Interleukin-12 (IL-12) is a multifunctional cytokine that induces Interferon (IFN)-gamma secretion and plays an important role in antitumor immunity. Interleukin-27 (IL-27) is a novel IL-12 family member, and the present studies demonstrate that IL-27 mediates a potent antitumor activity. The aim of this study was to investigate whether IL-12 and IL-27 gene polymorphisms and their serum levels are associated with glioma. We analyzed IL-12 gene 16974 A/C and IL-27 gene -964 A/G, 2905 T/G, and 4730 T/C polymorphisms in 210 patients with glioma and 220 matched controls, using polymerase chain reaction-restriction fragment length polymorphism method and DNA sequencing methods, while serum IL-12p40 and IL-27p28 levels were measured by enzyme-linked immunosorbent assay. Serum IL-12p40 and IL-27p28 levels were decreased in patients with glioma compared with controls (p < 0.01). There were significant differences in the genotype and allele frequencies of the IL-12 gene 16974 A/C polymorphism between the group of patients with glioma and the control group (p < 0.05). Moreover, genotypes carrying the IL-12 16974 C variant allele were associated with decreased serum IL-12p40 and IL-27p28 levels compared to the homozygous wild-type genotype in patients with glioma. The IL-12 gene 16974 A/C polymorphism may regulate expression of the serum IL-12p40 and IL-27p28, and associate with increased risk of glioma. Thus, genotypes carrying the IL-12 16974 C variant allele had a decreased ability to produce IL-12 and IL-27, which may contribute to glioma susceptibility.

Association of interleukin (IL)-12 and IL-27 gene polymorphisms with chronic obstructive pulmonary disease in a Chinese population

The pathogenesis of chronic obstructive pulmonary disease (COPD) is not fully understood, and environment and genetic factors have been investigated. Moreover, cytokine genes play an important role in COPD pathogenesis. However, the molecular mechanism of COPD induced by the factors is still unknown. The present study was undertaken to clarify a role of interleukin (IL)-12 16974A/C and IL-27 4730T/C, -964A/G, and 2905T/G polymorphisms in Chinese subjects with COPD. Polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) and sequence analyses were used to type IL-12 and IL-27 polymorphisms in 120 patients with COPD and 100 healthy controls. There were significant differences in the genotype and allele distribution of -964A/G and 2905T/G polymorphisms of the IL-27 gene among cases and controls in a Chinese population. When compared with the control group, subjects with AG genotype of the IL-27 -964A/G had a 2.22-fold decreased risk of COPD (odds ratio [OR] = 0.450, 95% confidence interval [CI]: 0.245-0.826; p = 0.009), and subjects with TG genotype of the IL-27 2905T/G had a 2.85-fold decreased risk of COPD (OR = 0.351, 95% CI: 0.137-0.899; p = 0.024). Compared with the TAT haplotype, the TGG haplotype was associated with a significantly decreased risk of COPD (OR = 0.29, 95% CI: 0.108-0.784; p = 0.010). Even after Bonferroni corrections, significant associations with COPD were observed for the AG genotype of the IL-27 -964A/G and the TGG haplotype of the IL-27 gene. Our data suggest that polymorphisms in the IL-27 gene may play a role in the development of COPD in Chinese population.

Genetic factors in autoimmune myasthenia gravis

Autoimmune myasthenia gravis (MG) is a multifactorial disease, markedly influenced by genetic factors, even though it shows limited heritability. The clinically typical form of autoimmune MG with thymus hyperplasia shows the most reproducible genetic associations, especially with the A1-B8-DR3 (8.1) haplotype of the major histocompatibility complex (MHC). However, because of strong linkage disequilibrium, the causative polymorphism in this region is not known yet. Increasing the density of genetic markers has nevertheless recently revealed the complex, but highly significant contribution of this essential genetic region in controlling the disease phenotype and the quantitative expression of serum autoantibodies. The advances of the human genome program, the development of genotyping and sequencing tools with increasing throughput, and the availability of powerful statistical methods now make feasible the dissection of a complex genetic region, such as the MHC and beyond, the systematic search throughout the genome for variants influencing disease predisposition. The identification of such functional variants should provide new clues to the pathogenesis of MG, as recently illustrated by the study of a promoter polymorphism of the CHRNA1 locus, influencing its thymic expression and central tolerance, or of a coding variant of the PTPN22 intracellular phosphatase.