Delivery of an miR155 inhibitor by anti-CD20 single-chain antibody into B cells reduces the acetylcholine receptor-specific autoantibodies and ameliorates experimental autoimmune myasthenia gravis

miRVim: Three-dimensional miRNA Structure Database

INTRODUCTION

MicroRNAs (miRNAs), a distinct category of non-coding RNAs, exert multifaceted regulatory functions in a variety of organisms, including humans, animals, and plants. The inventory of identified miRNAs stands at approximately 60,000 among all species and 1,926 in Homo sapiens manifests miRNA expression. Their theranostic role has been explored by researchers over the last few decades, positioning them as prominent therapeutic targets as our understanding of RNA targeting advances. However, limited availability of experimentally determined miRNA structures has constrained drug discovery efforts relying on virtual screening or computational methods, including machine learning and artificial intelligence.

METHODS

To address this lacuna, miRVim has been developed, providing a repository of human miRNA structures derived from both two-dimensional (MXFold2, CentroidFold, and RNAFold) and three-dimensional (RNAComposer and 3dRNA) structure prediction algorithms, in addition to experimentally available structures from the RCSB PDB repository.

RESULTS

miRVim contains 13,971 predicted secondary structures and 17,045 predicted three-dimensional structures filling the gap of unavailability of miRNA structure data bank. This database aims to facilitate computational data analysis for drug discovery, opening new avenues for advancing technologies such as machine learning-based predictions in the field of RNA biology.

CONCLUSION

The publicly accessible structures provided by miRVim, available at https://mirna.in/miRVim, offer a valuable resource for the research community, advancing the field of miRNA-related computational analysis and drug discovery.

The intricate dance of non-coding RNAs in myasthenia gravis pathogenesis and treatment

Myasthenia gravis (MG) stands as a perplexing autoimmune disorder affecting the neuromuscular junction, driven by a multitude of antibodies targeting postsynaptic elements. However, the mystery of MG pathogenesis has yet to be completely uncovered, and its heterogeneity also challenges diagnosis and treatment. Growing evidence shows the differential expression of non-coding RNAs (ncRNAs) in MG has played an essential role in the development of MG in recent years. Remarkably, these aberrantly expressed ncRNAs exhibit distinct profiles within diverse clinical subgroups and among patients harboring various antibody types. Furthermore, they have been implicated in orchestrating the production of inflammatory cytokines, perturbing the equilibrium of T helper 1 cells (Th1), T helper 17 cells (Th17), and regulatory T cells (Tregs), and inciting B cells to generate antibodies. Studies have elucidated that certain ncRNAs mirror the clinical severity of MG, while others may hold therapeutic significance, showcasing a propensity to return to normal levels following appropriate treatments or potentially foretelling the responsiveness to immunosuppressive therapies. Notably, the intricate interplay among these ncRNAs does not follow a linear trajectory but rather assembles into a complex network, with competing endogenous RNA (ceRNA) emerging as a prominent hub in some cases. This comprehensive review consolidates the landscape of dysregulated ncRNAs in MG, briefly delineating their pivotal role in MG pathogenesis. Furthermore, it explores their promise as prospective biomarkers, aiding in the elucidation of disease subtypes, assessment of disease severity, monitoring therapeutic responses, and as novel therapeutic targets.

MicroRNA‑155‑5p affects regulatory T cell activation and immunosuppressive function by targeting BCL10 in myasthenia gravis

The imbalance in immune homeostasis plays a crucial role in the pathogenesis of myasthenia gravis (MG). MicroRNAs (miRs) have been identified as key regulators of immune homeostasis. B-cell lymphoma/leukemia 10 (BCL10) has been implicated in the activation and suppressive function of regulatory T cells (Tregs). This study aimed to investigate the potential role of miR-155-5p in modulating the activation and function of Tregs in MG. To achieve this objective, blood samples were collected from MG patients to assess the expression levels of miR-155-5p and BCL10, as well as the proportion of circulating Tregs, in comparison to healthy controls. The correlation between miR-155-5p and BCL10 levels was evaluated in human samples. The expression levels of miR-155-5p and the numbers of circulating Tregs were also examined in an animal model of experimental autoimmune MG (EAMG). A dual-luciferase reporter assay was used to verify whether miR-155-5p can target BCL10. To determine the regulatory function of BCL10 in Tregs, CD4+ CD25+ Tregs were transfected with either small interfering-BCL10 or miR-155-5p inhibitor, and the expression levels of the anti-inflammatory cytokine IL-10 and transcription factors Foxp3, TGF-β1, CTLA4, and ICOS were measured. The results demonstrated that the expression level of miR-155-5p was significantly higher in patients with MG compared with that in healthy controls, whereas the expression level of BCL10 was significantly decreased in patients with MG. Furthermore, there was a significant negative correlation between the expression levels of miR-155-5p and BCL10. The number of circulating Tregs was significantly reduced in patients with MG and in the spleen of rats with EAMG compared with that in the corresponding control groups. The dual-luciferase reporter assay demonstrated that miR-155-5p could target BCL10. The Tregs transfected with si-BCL10 demonstrated significant decreases in the protein levels of TGF-β1 and IL-10, as well as in the mRNA expression levels of Foxp3, TGF-β1, CTLA-4 and ICOS. Conversely, the Tregs transfected with the miR-155-5p inhibitor exhibited a substantial increase in these protein and mRNA expression levels compared with their respective control groups. Furthermore, the knockdown of BCL10 exhibited a decline in the suppressive efficacy of Tregs on the proliferation of CD4+ T cells. Conversely, the suppression of miR-155-5p expression attenuated the inhibition of the BCL10 gene, potentially causing an indirect influence on the suppressive capability of Tregs on the proliferation of CD4+ T cells. BCL10 was thus found to contribute to the activation and immunosuppressive function of Tregs. In summary, the present study demonstrated that miR-155-5p inhibited the activation and immunosuppressive function of Tregs by targeting BCL10, which may be used as a future potential target for the treatment of MG.

miRNAs as the important regulators of myasthenia gravis: involvement of major cytokines and immune cells

Myasthenia gravis (MG) is a type of muscle paralysis created by immune responses against acetylcholine receptor proteins in neuromuscular synapses. This disease is characterized by muscle weakness, especially ocular weakness symptoms that could be ptosis (fall of the upper eyelid) or diplopia (double vision of a single object). Some patients also identified with speech and swallowing problems. The main goals of MG therapeutic approaches are to achieve remission, reduce symptoms, and improve life quality. Recently, other studies have revealed the potential role of various microRNAs (miRNAs) in the development of MG through different mechanisms and have proposed these molecules as effective biomarkers for the treatment of MG. This review was aimed at providing an overview of the critical regulatory roles of various miRNAs in the pathogenesis of this autoimmune disease focusing on human MG studies and the interaction between different miRNAs with important cytokines and immune cells during the development of this autoimmune disease.

MicroRNAs, Stem Cells in Bipolar Disorder, and Lithium Therapeutic Approach

Bipolar disorder (BD) is a severe, chronic, and disabling neuropsychiatric disorder characterized by recurrent mood disturbances (mania/hypomania and depression, with or without mixed features) and a constellation of cognitive, psychomotor, autonomic, and endocrine abnormalities. The etiology of BD is multifactorial, including both biological and epigenetic factors. Recently, microRNAs (miRNAs), a class of epigenetic regulators of gene expression playing a central role in brain development and plasticity, have been related to several neuropsychiatric disorders, including BD. Moreover, an alteration in the number/distribution and differentiation potential of neural stem cells has also been described, significantly affecting brain homeostasis and neuroplasticity. This review aimed to evaluate the most reliable scientific evidence on miRNAs as biomarkers for the diagnosis of BD and assess their implications in response to mood stabilizers, such as lithium. Neural stem cell distribution, regulation, and dysfunction in the etiology of BD are also dissected.

MicroRNA expression profiles of peripheral blood and mononuclear cells in myasthenia gravis: A systematic review

BACKGROUND

Studies have described the role of microRNAs (miRNAs) in thymic function, along with directly observing the altered expression of miRNAs in thymuses of myasthenia gravis (MG) patients; so, miRNAs became a core component in the pathophysiology of MG. However, because the miRNA analysis results are contradictory, the identification of MG-related miRNAs is daunting.

OBJECTIVE

We did a systematic review of studies analyzing the miRNA expression profile of peripheral blood and mononuclear cells for patients with MG.

METHODS

We ran a database search in PubMed, Scopus, and Web of Science on August 17, 2021. Original articles that analyzed miRNA profiles in peripheral blood (serum, plasma, and whole blood) and peripheral blood mononuclear cells (PBMCs) for patients with MG in comparison with a non-MG or healthy control (HC) group were eligible. The quality of studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2).

RESULTS

26 studies were included. The quality of studies was fair (median score, 5). Among 226 different miRNAs that were deregulated in at least one study (range, 1-87), ten miRNAs were significantly deregulated in three or more studies. Five miRNAs (50%) showed the same deregulation: miR-106b-3p and miR-21-5p were consistently upregulated, and miR-20b, miR-15b, and miR-16 were consistently downregulated. Also, there were five miRNAs that were mostly upregulated, miR-150-5p, miR-146a, miR-30e-5p, and miR-338-3p, or downregulated, miR-324-3p, across studies.

CONCLUSION

These miRNAs contribute to different pathways, importantly neural apoptosis and autophagy, inflammation, T regulatory cell development, and T helper cell balance. Prior to being used for diagnostic and therapeutic purposes, it is required to pursue molecular mechanisms these consistently and mostly dysregulated miRNAs specifically use in the context of MG.

Myasthenia Gravis: An Acquired Interferonopathy?

Myasthenia gravis (MG) is a rare autoimmune disease mediated by antibodies against components of the neuromuscular junction, particularly the acetylcholine receptor (AChR). The thymus plays a primary role in AChR-MG patients. In early-onset AChR-MG and thymoma-associated MG, an interferon type I (IFN-I) signature is clearly detected in the thymus. The origin of this chronic IFN-I expression in the thymus is not yet defined. IFN-I subtypes are normally produced in response to viral infection. However, genetic diseases called interferonopathies are associated with an aberrant chronic production of IFN-I defined as sterile inflammation. Some systemic autoimmune diseases also share common features with interferonopathies. This review aims to analyze the pathogenic role of IFN-I in these diseases as compared to AChR-MG in order to determine if AChR-MG could be an acquired interferonopathy.

A Review on the Role of Non-Coding RNAs in the Pathogenesis of Myasthenia Gravis

Myasthenia gravis (MG) is an autoimmune condition related to autoantibodies against certain proteins in the postsynaptic membranes in the neuromuscular junction. This disorder has a multifactorial inheritance. The connection between environmental and genetic factors can be established by epigenetic factors, such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). XLOC_003810, SNHG16, IFNG-AS1, and MALAT-1 are among the lncRNAs with a possible role in the pathoetiology of MG. Moreover, miR-150-5p, miR-155, miR-146a-5p, miR-20b, miR-21-5p, miR-126, let-7a-5p, and let-7f-5p are among miRNAs whose roles in the pathogenesis of MG has been assessed. In the current review, we summarize the impact of miRNAs and lncRNAs in the development or progression of MG.

MicroRNAs and nervous system diseases: network insights and computational challenges

The nervous system is one of the most complex biological systems, and nervous system disease (NSD) is a major cause of disability and mortality. Extensive evidence indicates that numerous dysregulated microRNAs (miRNAs) are involved in a broad spectrum of NSDs. A comprehensive review of miRNA-mediated regulatory will facilitate our understanding of miRNA dysregulation mechanisms in NSDs. In this work, we summarized currently available databases on miRNAs and NSDs, star NSD miRNAs, NSD spectrum width, miRNA spectrum width and the distribution of miRNAs in NSD sub-categories by reviewing approximately 1000 studies. In addition, we characterized miRNA-miRNA and NSD-NSD interactions from a network perspective based on miRNA-NSD benchmarking data sets. Furthermore, we summarized the regulatory principles of miRNAs in NSDs, including miRNA synergistic regulation in NSDs, miRNA modules and NSD modules. We also discussed computational challenges for identifying novel miRNAs in NSDs. Elucidating the roles of miRNAs in NSDs from a network perspective would not only improve our understanding of the precise mechanism underlying these complex diseases, but also provide novel insight into the development, diagnosis and treatment of NSDs.

Implications the Role of miR-155 in the Pathogenesis of Autoimmune Diseases

MicroRNAs (miRNAs) are small noncoding conserved RNAs containing 19 to 24 nucleotides that are regulators of post-translational modifications and are involved in the majority of biological processes such as immune homeostasis, T helper cell differentiation, central and peripheral tolerance, and immune cell development. Autoimmune diseases are characterized by immune system dysregulation, which ultimately leads to destructive responses to self-antigens. A large body of literature suggests that autoimmune diseases and immune dysregulation are associated with different miRNA expression changes in the target cells and tissues of adaptive or innate immunity. miR-155 is identified as a critical modulator of immune responses. Recently conducted studies on the expression profile of miR-155 suggest that the altered expression and function of miR-155 can mediate vulnerability to autoimmune diseases and cause significant dysfunction of the immune system.

The Roles of MicroRNAs in Male Infertility

MicroRNAs applications were vastly studied throughout the years, spanning from potential cancer biomarkers to targeted therapies for various diseases. Out of these utilizations, this paper focuses on their role in male infertility. Approximately 10–15% of worldwide couples are affected by infertility. Out of these, 50% are due to male determinants. The majority of cases still have an undetermined cause. Previous studies have found that the aberrant expression of microRNAs could be linked to certain reproductive dysfunctions in males. Further on, this study looked into the most recent literature published on this subject in order to assess the connection between the up-/down-regulation of various microRNAs and the roles they play in male infertility. MicroRNAs were found to be abundant and stable in the seminal liquid, which led to a facile identification using regular RNA detection methods. It was observed that the concentration of microRNAs in semen was modified in the case of patients suffering from asthenozoospermia and azoospermia. Moreover, idiopathic male infertility was associated with a single nucleotide polymorphism of the microRNA binding site. Future studies should focus their attention on discovering future treatments against male infertility targeting specific microRNAs and also on developing new and improved contraceptive methods.

Non-coding RNAs: the new central dogma of cancer biology

The central dogma of molecular biology states that the functions of RNA revolve around protein translation. Until the last decade, most researches were geared towards characterization of RNAs as intermediaries in protein translation, namely, messenger RNAs (mRNAs) as temporary copies of genetic information, ribosomal RNAs (rRNAs) as a main component of ribosome, or translators of codon sequence (tRNAs). The statistical reality, however, is that these processes account for less than 2% of the genome, and insufficiently explain the functionality of 98% of transcribed RNAs. Recent discoveries have unveiled thousands of unique non-coding RNAs (ncRNAs) and shifted the perception of them from being "junk" transcriptional products to "yet to be elucidated"-and potentially monumentally important-RNAs. Most ncRNAs are now known as key regulators in various networks in which they could lead to specific cellular responses and fates. In major cancers, ncRNAs have been identified as both oncogenic drivers and tumor suppressors, indicating a complex regulatory network among these ncRNAs. Herein, we provide a comprehensive review of the various ncRNAs and their functional roles in cancer, and the pre-clinical and clinical development of ncRNA-based therapeutics. A deeper understanding of ncRNAs could facilitate better design of personalized therapeutics.

Emerging Roles of Dysregulated MicroRNAs in Myasthenia Gravis

Myasthenia gravis (MG) is a rare acquired autoimmune neuromuscular disease. Autoantibodies, cellular immunity, complement, and cytokines are involved in the pathogenesis of MG. It is characterized by the dysfunction of neuromuscular junction transmission and skeletal muscle weakness. MicroRNAs (miRNAs) are non-coding small molecule ribonucleic acids that regulate various biological processes (e.g., development, differentiation, and immunity) at the transcriptional and post-transcriptional levels of gene expression. miRNAs play an important regulatory role in the pathogenesis of autoimmune diseases, including MG. In recent studies, the functional mechanisms underlying the role of miRNAs in the pathogenesis of MG have received increasing attention. miRNAs are highly stable and have high specificity in peripheral body fluids. Therefore, the miRNAs in body fluids may represent promising biomarkers for determining the prognosis of MG and the efficacy of treatment. This article reviews the role of miRNAs in the pathogenesis of MG, highlights the potential of miRNAs as new biomarkers for the diagnosis of MG, and deepens our understanding of disease processes.

miRNAs as Biomarkers in Disease: Latest Findings Regarding Their Role in Diagnosis and Prognosis

MicroRNAs (miRNAs) represent a class of small, non-coding RNAs with the main roles of regulating mRNA through its degradation and adjusting protein levels. In recent years, extraordinary progress has been made in terms of identifying the origin and exact functions of miRNA, focusing on their potential use in both the research and the clinical field. This review aims at improving the current understanding of these molecules and their applicability in the medical field. A thorough analysis of the literature consulting resources available in online databases such as NCBI, PubMed, Medline, ScienceDirect, and UpToDate was performed. There is promising evidence that in spite of the lack of standardized protocols regarding the use of miRNAs in current clinical practice, they constitute a reliable tool for future use. These molecules meet most of the required criteria for being an ideal biomarker, such as accessibility, high specificity, and sensitivity. Despite present limitations, miRNAs as biomarkers for various conditions remain an impressive research field. As current techniques evolve, we anticipate that miRNAs will become a routine approach in the development of personalized patient profiles, thus permitting more specific therapeutic interventions.

Reduction of CD19 autoimmunity marker on B cells of paediatric SLE patients through repressing PU.1/TNF-α/BAFF axis pathway by miR-155

microRNA-155 (miR-155) is implicated in regulating B-cell activation and survival that is important in systemic lupus erythematosus (SLE) pathogenesis. PU.1, a target for miR-155, is a crucial regulator of B-cell development and enhances Tumour-Necrosis-factor-alpha (TNF-α) expression. TNF-α induces the expression of B-cell-activating-factor (BAFF). BAFF is reported to increase the expression of the autoimmunity marker; CD19. This study aimed to investigate the regulation of expression of PU.1 in pediatric-systemic-lupus-erythematosus (pSLE) patients by miR-155, and hence evaluate its impact on TNF-α/BAFF/CD19 signalling pathway. Screening revealed that PU.1 is upregulated in PBMCs and B-cells of pSLE patients. PU.1 expression directly correlated with systemic-lupus-erythematosus disease-activity-index-2 K SLEDAI-2K. Ectopic expression of miR-155 and knockdown of PU.1 suppressed PU.1, TNF-α and BAFF. Finally, miR-155 decreased the proportion of BAFF-expressing-B-cells and CD19 protein expression. These findings suggest that miR-155 suppresses autoimmunity through transcriptional repression of PU.1 and TNF-α, which in turn suppresses BAFF and CD19 protein expression.

Noncoding RNAs in Cancer Immunology

Cancer immunology is the study of interaction between cancer cells and immune system by the application of immunology principle and theory. With the recent approval of several new drugs targeting immune checkpoints in cancer, cancer immunology has become a very attractive field of research and is thought to be the new hope to conquer cancer. This chapter introduces the aberrant expression and function of noncoding RNAs, mainly microRNAs and long noncoding RNAs, in tumor-infiltrating immune cells, and their significance in tumor immunity. It also illustrates how noncoding RNAs are shuttled between tumor cells and immune cells in tumor microenvironments via exosomes or other microvesicles to modulate tumor immunity.

Construction of an miRNA-regulated drug-pathway network reveals drug repurposing candidates for myasthenia gravis

Myasthenia gravis (MG) is a rare debilitating autoimmune neuromuscular disorder. Many studies have focused on the mechanism and treatment strategies of MG. However, the exact pathogenesis of MG and effective treatment strategies remain unclear. Recent studies have indicated that microRNAs (miRNAs or miRs) can regulate the pathological pathways of MG, suggesting their potential role in novel treatments. In the present study, we created a comprehensive catalog of experimentally confirmed MG risk genes and miRNAs by manually mining published literature and public databases. Based on these genes and miRNAs, we identified 41 MG risk pathways and 105 approved drugs that can affect these pathways. Some important MG-related pathways, such as hsa04060 (cytokine-cytokine receptor interaction) and hsa05200 (pathway in cancer), were found to be regulated by MG risk miRNAs and drugs. Furthermore, we constructed an miRNA-regulated drug-pathway network and identified miRNAs and drugs that synergistically regulate key MG pathways and biological processes. We developed a drug repurposing strategy to identify 25 drug repurposing candidates for MG; several of these drugs, such as rituximab, adalimumab, sunitinib, and muromonab, have the potential to be novel MG treatment drugs. This study provides novel insight into the pathogenesis of MG and potential drug candidates for MG were identified.

Contribution of MicroRNAs to autoimmune diseases

MicroRNAs are a class of evolutionarily conserved, short non-coding RNAs that post-transcriptionally modulate the expression of multiple target genes. They are implicated in almost every biological process, including pathways involved in immune homeostasis, such as immune cell development, central and peripheral tolerance, and T helper cell differentiation. Alterations in miRNA expression and function can lead to major dysfunction of the immune system and mediate susceptibility to autoimmune disease. Here, we discuss the role of miRNAs in the maintenance of immune tolerance to self-antigens and the gain or loss of miRNA functions on tissue inflammation and autoimmunity.

Animal models of myasthenia gravis: utility and limitations

Myasthenia gravis (MG) is a chronic autoimmune disease caused by the immune attack of the neuromuscular junction. Antibodies directed against the acetylcholine receptor (AChR) induce receptor degradation, complement cascade activation, and postsynaptic membrane destruction, resulting in functional reduction in AChR availability. Besides anti-AChR antibodies, other autoantibodies are known to play pathogenic roles in MG. The experimental autoimmune MG (EAMG) models have been of great help over the years in understanding the pathophysiological role of specific autoantibodies and T helper lymphocytes and in suggesting new therapies for prevention and modulation of the ongoing disease. EAMG can be induced in mice and rats of susceptible strains that show clinical symptoms mimicking the human disease. EAMG models are helpful for studying both the muscle and the immune compartments to evaluate new treatment perspectives. In this review, we concentrate on recent findings on EAMG models, focusing on their utility and limitations.

Mini but mighty: microRNAs in the pathobiology of periodontal disease

MicroRNAs (miRNAs) are a family of small, noncoding RNA molecules that negatively regulate protein expression either by inhibiting initiation of the translation of mRNA or by inducing the degradation of mRNA molecules. Accumulating evidence suggests that miRNA-mediated repression of protein expression is of paramount importance in a broad range of physiologic and pathologic conditions. In particular, miRNA-induced dysregulation of molecular processes involved in inflammatory pathways has been shown to contribute to the development of chronic inflammatory diseases. In this review, first of all we provide an overview of miRNA biogenesis, the main mechanisms of action and the miRNA profiling tools currently available. Then, we summarize the available evidence supporting a specific role for miRNAs in the pathobiology of periodontitis. Based on a review of available data on the differential expression of miRNAs in gingival tissues in states of periodontal health and disease, we address specific roles for miRNAs in molecular and cellular pathways causally linked to periodontitis. Our review points to several lines of evidence suggesting the involvement of miRNAs in periodontal tissue homeostasis and pathology. Although the intricate regulatory networks affected by miRNA function are still incompletely mapped, further utilization of systems biology tools is expected to enhance our understanding of the pathobiology of periodontitis.

Detecting key genes regulated by miRNAs in dysfunctional crosstalk pathway of myasthenia gravis

Myasthenia gravis (MG) is a neuromuscular autoimmune disorder resulting from autoantibodies attacking components of the neuromuscular junction. Recent studies have implicated the aberrant expression of microRNAs (miRNAs) in the pathogenesis of MG; however, the underlying mechanisms remain largely unknown. This study aimed to identify key genes regulated by miRNAs in MG. Six dysregulated pathways were identified through differentially expressed miRNAs and mRNAs in MG, and significant crosstalk was detected between five of these. Notably, crosstalk between the "synaptic long-term potentiation" pathway and four others was mediated by five genes involved in the MAPK signaling pathway. Furthermore, 14 key genes regulated by miRNAs were detected, of which six-MAPK1, RAF1, PGF, PDGFRA, EP300, and PPP1CC-mediated interactions between the dysregulated pathways. MAPK1 and RAF1 were responsible for most of this crosstalk (80%), likely reflecting their central roles in MG pathogenesis. In addition, most key genes were enriched in immune-related local areas that were strongly disordered in MG. These results provide new insight into the pathogenesis of MG and offer new potential targets for therapeutic intervention.

MicroRNA silencing for cancer therapy targeted to the tumour microenvironment

MicroRNAs are short non-coding RNAs expressed in different tissue and cell types that suppress the expression of target genes. As such, microRNAs are critical cogs in numerous biological processes, and dysregulated microRNA expression is correlated with many human diseases. Certain microRNAs, called oncomiRs, play a causal role in the onset and maintenance of cancer when overexpressed. Tumours that depend on these microRNAs are said to display oncomiR addiction. Some of the most effective anticancer therapies target oncogenes such as EGFR and HER2; similarly, inhibition of oncomiRs using antisense oligomers (that is, antimiRs) is an evolving therapeutic strategy. However, the in vivo efficacy of current antimiR technologies is hindered by physiological and cellular barriers to delivery into targeted cells. Here we introduce a novel antimiR delivery platform that targets the acidic tumour microenvironment, evades systemic clearance by the liver, and facilitates cell entry via a non-endocytic pathway. We find that the attachment of peptide nucleic acid antimiRs to a peptide with a low pH-induced transmembrane structure (pHLIP) produces a novel construct that could target the tumour microenvironment, transport antimiRs across plasma membranes under acidic conditions such as those found in solid tumours (pH approximately 6), and effectively inhibit the miR-155 oncomiR in a mouse model of lymphoma. This study introduces a new model for using antimiRs as anti-cancer drugs, which can have broad impacts on the field of targeted drug delivery.

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.