Altered miRNA expression in T regulatory cells in course of multiple sclerosis

T cell Subsets in Peripheral Blood of Women with Recurrent Implantation Failure

The objective of this study was to determine whether there are any differences in the T cell composition and the expression of specific factors (i.e., IRF4, TBX21, GATA3, and GITR) of T cells between women with Repeated Implantation Failure (RIF) and fertile women. We observed a decrease in circulating Tregs and exhausted CD8 + T cells in RIF patients when compared to the controls whereas exhausted Treg and Th17 cells were more frequent. Using real-time PCR, we determined that the expression of IRF-4 and TBX21 was significantly elevated in the cases. In contrast, mRNAs encoding GATA3 and GITR were reduced. Furthermore, the expression of some miRNAs involved in T cell differentiation and their target gene candidates were examined in T cells from women with RIF and fertile control women. The patients showed significant up-regulation of miR-25, miR-93, and miR-326. miR-155 and miR-146a demonstrated significant down-regulation in RIF patients. The results revealed that the expression pattern of target genes was in line with data for miRNAs expression from purified Treg and Th17 cells. The findings of real-time PCR analysis provided insights into the genetic pathways underlying this aberration in the proportions of T cell subsets. Our data suggest that a combination of higher pro-inflammatory Th17 and exhausted Treg cells, and lower Treg and exhausted CD8 + T cells may co-exist in the peripheral blood of women with RIF. Moreover, the expression level of transcription factors and miRNAs controlling T cell differentiation may differ in women with RIF influencing pregnancy outcomes in these women.

Neuronal microRNA regulation in Experimental Autoimmune Encephalomyelitis

Multiple sclerosis (MS) is an autoimmune, neurodegenerative disease but the molecular mechanisms underlying neurodegenerative aspects of the disease are poorly understood. microRNAs (miRNAs) are powerful regulators of gene expression that regulate numerous mRNAs simultaneously and can thus regulate programs of gene expression. Here, we describe miRNA expression in neurons captured from mice subjected to experimental autoimmune encephalomyelitis (EAE), a model of central nervous system (CNS) inflammation. Lumbar motor neurons and retinal neurons were laser captured from EAE mice and miRNA expression was assessed by next-generation sequencing and validated by qPCR. We describe 14 miRNAs that are differentially regulated in both neuronal subtypes and determine putative mRNA targets though in silico analysis. Several upregulated neuronal miRNAs are predicted to target pathways that could mediate repair and regeneration during EAE. This work identifies miRNAs that are affected by inflammation and suggests novel candidates that may be targeted to improve neuroprotection in the context of pathological inflammation.

A simple and universal enzyme-free approach for the detection of multiple microRNAs using a single nanostructured enhancer of surface plasmon resonance imaging

Here we describe a simple approach for the simultaneous detection of multiple microRNAs (miRNAs) using a single nanostructured reagent as surface plasmon resonance imaging (SPRi) enhancer and without using enzymatic reactions, sequence specific enhancers or multiple enhancing steps as normally reported in similar studies. The strategy involves the preparation and optimisation of neutravidin-coated gold nanospheres (nGNSs) functionalised with a previously biotinylated antibody (Ab) against DNA/RNA hybrids. The Ab guarantees the recognition of any miRNA sequence adsorbed on a surface properly functionalised with different DNA probes; at the same time, gold nanoparticles permit to detect this interaction, thus producing enough SPRi signal even at a low ligand concentration. After a careful optimisation of the nanoenhancer and after its characterisation, the final assay allowed the simultaneous detection of four miRNAs with a limit of detection (LOD) of up to 0.5 pM (equal to 275 attomoles in 500 μL) by performing a single enhancing injection. The proposed strategy shows good signal specificity and permits to discriminate wild-type, single- and triple-mutated sequences much better than non-enhanced SPRi. Finally, the method works properly in complex samples (total RNA extracted from blood) as demonstrated by the detection of four miRNAs potentially related to multiple sclerosis used as case study. This proof-of-concept study confirms that the approach provides the possibility to detect a theoretically unlimited number of miRNAs using a simple protocol and an easily prepared enhancing reagent, and may further facilitate the development of affordable multiplexing miRNA screening for clinical purposes.

A myriad of roles of miR-25 in health and disease

Small non-coding RNAs including microRNAs (miRNAs) have been recently recognized as important regulators of gene expression. MicroRNAs play myriads of roles in physiological processes as well as in the pathogenesis of a number of diseases by translational repression or mRNA destabilization of numerous target genes. The miR-106b-25 cluster is highly conserved in vertebrates and consists of three members including miR-106b, miR-93 and miR-25. MiR-106b and miR-93 share the same seed sequences; however, miR-25 has only a similar seed sequence resulting in different predicted target mRNAs. In this review, we specifically focus on the role of miR-25 in healthy and diseased conditions. Many of miR-25 target mRNAs are involved in biological processes such as cell proliferation, differentiation, and migration, apoptosis, oxidative stress, inflammation, calcium handling, etc. Therefore, it is no surprise that miR-25 has been reported as a key regulator of common cancerous and non-cancerous diseases. MiR-25 plays an important role in the pathogenesis of acute myocardial infarction, left ventricular hypertrophy, heart failure, diabetes mellitus, diabetic nephropathy, tubulointerstitial nephropathy, asthma bronchiale, cerebral ischemia/reperfusion injury, neurodegenerative diseases, schizophrenia, multiple sclerosis, etc. MiR-25 is also a well-described oncogenic miRNA playing a crucial role in the development of many tumor types including brain tumors, lung, breast, ovarian, prostate, thyroid, oesophageal, gastric, colorectal, hepatocellular cancers, etc. In this review, our aim is to discuss the translational therapeutic role of miR-25 in common diseased conditions based on relevant basic research and clinical studies.

Analysis of the expression of mir-34a, mir-199a, mir-30c and mir-19a in peripheral blood CD4+T lymphocytes of relapsing-remitting multiple sclerosis patients

BACKGROUND

Multiple sclerosis is an immune-mediated inflammatory disease of central nervous system. MicroRNAs play important roles in autoimmune diseases such as MS.

OBJECTIVES

The aim was to evaluate the expression pattern of miR-34a, miR-199a, miR-30c and miR-19a in peripheral blood derived CD4+ T lymphocytes of both relapsing and remitting phases of MS.

METHODS

Blood samples from 40 RRMS patients (20 in relapsing and 20 in remitting phase) and 20 healthy volunteers were taken. CD4+ T cells were isolated. The expression level of miR-34a, miR-199a, miR-30c and miR-19a, and the percentage of Th17 and Treg cells were measured. Expression of master transcription factors of Th17 and Treg cells and several targets of these miRNAs were also evaluated.

RESULTS

Data indicated an increased expression of miR-34a, miR-30c and miR-19a in relapsing phase and decreased expression of miR-199a in remitting phase. ROC curve data add other prestigious information of miR-34a, miR-199a, miR-30c and miR-19a by defining relapsing and remitting phase and also healthy cases with high specificity and sensitivity at a proposed optimum cut-off point.

CONCLUSION

Collectively, we showed a correlation between the four miRNAs with different phases of MS and their possible involvement in differentiation pathways of Th17 cells, as the most important players in MS.

Exosome-associated miRNA profile as a prognostic tool for therapy response monitoring in multiple sclerosis patients

Multiple sclerosis (MS) is an autoimmune pathology leading to neurodegeneration. Because of the complexity and heterogenic etiology of this disease, diagnosis and treatment for individual patients are challenging. Exosome-associated microRNAs (miRNAs) have recently emerged as a new class of diagnostic biomarkers involved in both autoimmune and neurologic disorders. Interesting new evidence has emerged showing that circulating miRNAs are dysregulated in MS body fluids, including serum, plasma, and cerebrospinal fluid. We hypothesized that exosome-associated miRNAs could present a readily accessible blood-based assay for MS disease. We detected expression of miRNAs by quantitative PCR on a small cohort of MS patients. We analyzed circulating exosome-associated miRNAs of MS patients before and after therapy and found that 14 exosome-associated miRNAs were significantly down-regulated, while 2 exosome-associated miRNAs were significantly up-regulated in IFN-β-treated relapsing-remitting MS patients with response to therapy compared to those without response. We identified a serum miRNA panel that could be used to monitor the response to IFN-β therapy. Overall, these data suggest that circulating exosome-associated miRNA profiling could represent an easily detectable biomarker of disease and treatment response.-Manna, I., Iaccino, E., Dattilo, V., Barone, S., Vecchio, E., Mimmi, S., Filippelli, E., Demonte, G., Polidoro, S., Granata, A., Scannapieco, S., Quinto, I., Valentino, P., Quattrone, A. Exosome-associated miRNA profile as a prognostic tool for therapy response monitoring in multiple sclerosis patients.

Nanocurcumin restores aberrant miRNA expression profile in multiple sclerosis, randomized, double-blind, placebo-controlled trial

In the current study, we aimed to identify nanocurcumin effects on microRNAs (miRNAs) in the peripheral blood of patients with relapsing-remitting multiple sclerosis (RRMS). We intended to investigate the expression pattern of these miRNAs in experimental settings in vivo. The expression levels of the selected 27 miRNAs known to be involved in the regulation of immune responses were analyzed in 50 RRMS patients and 35 healthy controls. The miRNA expression profiles were investigated by quantitative PCR (qPCR) at baseline and after 6 months of nanocurcumin therapy. Our data revealed that the expression of a number of microRNAs including miR-16, miR-17-92, miR-27, miR-29b, miR-126, miR-128, miR-132, miR-155, miR-326, miR-550, miR-15a, miR-19b, miR-106b, miR-320a, miR-363, miR-31, miR-150, and miR-340 is regulated by nanocurcumin. The results of the current work indicate that nanocurcumin is able to restore the expression pattern of dysregulated miRNAs in MS patients. We discovered that some miRNAs are deregulated in untreated patients compared with healthy controls and nanocurcumin-treated patients. This is a new finding that might represent the potential contribution of these miRNAs to MS pathogenesis. Taken together, these data provide novel insights into miRNA-dependent regulation of the function of B and T cells in MS disease and enrich our understanding of the effects mediated by a therapeutic approach that targets B and T cells.

Downregulation of miR-106b attenuates inflammatory responses and joint damage in collagen-induced arthritis

Objective

miRNAs are small, signal-strand, non-coding RNAs that function in post-transcriptional regulation. We analysed the in vivo effect of miR-106b (miR-106b-5p) on inflammatory bone loss in CIA mice.

Methods

CIA mice are developed by injecting DAB/1 mice with bovine type II collagen containing Freund's adjuvant and then the in vivo effect of miR-106b is examined. On day 22, mice were given lentiviral negative control, lentiviral-mediated miR-106b mimics or lentiviral-mediated miR-106b inhibitor via orbital injection on a weekly basis. Morphological changes in the ankle joints were assessed via micro-CT and histopathology and cytokine expression levels were examined via immunohistochemical staining, ELISA or flow cytometric analysis. miR-106b and osteoclastic-related gene expression was evaluated via quantitative real-time PCR.

Results

CIA mice were found to have increased miR-106b expression and CIA-associated bone loss and inflammatory infiltration. miR-106b inhibitor treatment markedly decreased arthritis incidence and attenuated bone destruction and histological severity compared with the control group. Moreover, miR-106b inhibitor treatment suppressed RANK ligand (RANKL) expression, increased osteoprotegerin (OPG) expression and reduced the RANKL:OPG ratio in CIA mice. miR-106b inhibition also significantly decreased inflammatory mediator production in joint sections and reduced serum pro-inflammatory cytokine levels when compared with the control group. Additionally, miR-106b inhibition decreased tartrate-resistant acid phosphatase-positive cell numbers and suppressed murine bone marrow macrophage differentiation.

Conclusion

These findings indicate that miR-106b inhibition can ameliorate CIA-associated inflammation and bone destruction and thus may serve as a potential therapeutic for human RA treatment.

[MiRNAs: new actors in the physiopathology of multiple sclerosis]

Multiple sclerosis (MS) is an auto-immune demyelinating disorder characterized by a chronic neuro-inflammatory process associated with an infiltration of the central nervous system (CNS) by autoreactive lymphocytes. The etiology of the disease remains unclear but the recent discovery of a dysregulated miRNA network in both cells and extracellular fluids of MS patients has brought new insights on the pathophysiological mechanisms involved in this disorder. miRNAs can induce a T cell polarization towards a pathological Th17 or Th1 phenotype and a deleterious activation of microglia, the CNS-resident macrophages. We provide here a review of the most recent data regarding miRNA dysregulation and pathophysiological roles in MS patients and in the animal model of MS, EAE (experimental autoimmune encephalomyelitis). Moreover, we discuss the putative clinical value of miRNAs as a novel biomarker and diagnostic tool for MS.

MicroRNA-142 regulates inflammation and T cell differentiation in an animal model of multiple sclerosis

Background

MicroRNAs have emerged as an important class of modulators of gene expression. These molecules influence protein synthesis through translational repression or degradation of mRNA transcripts. Herein, we investigated the potential role of miR-142a isoforms, miR-142a-3p and miR-142a-5p, in the context of autoimmune neuroinflammation.

Methods

The expression levels of two mature isoforms of miR-142 were measured in the brains of patients with multiple sclerosis (MS) and the CNS tissues from mice with experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Expression analyses were also performed in mitogen and antigen-stimulated splenocytes, as well as macrophages and astrocytes using real-time RT-PCR. The role of the mature miRNAs was then investigated in T cell differentiation by transfection of CD4⁺ T cells, followed by flow cytometric analysis of intracellular cytokines. Luciferase assays using vectors containing the 3′UTR of predicted targets were performed to confirm the interaction of miRNA sequences with transcripts. Expression of targets were then analyzed in activated splenocytes and MS/EAE tissues.

Results

Expression of miR-142-5p was significantly increased in the frontal white matter from MS patients compared with white matter from non-MS controls. Likewise, expression levels of miR-142a-5p and miR-142a-3p showed significant upregulation in the spinal cords of EAE mice at days 15 and 25 post disease induction. Splenocytes stimulated with myelin oligodendrocyte glycoprotein (MOG) peptide or anti-CD3/anti-CD28 antibodies showed upregulation of miR-142a-5p and miR-142a-3p isoforms, whereas stimulated bone marrow-derived macrophages and primary astrocytes did not show any significant changes in miRNA expression levels. miR-142a-5p overexpression in activated lymphocytes shifted the pattern of T cell differentiation towards Th1 cells. Luciferase assays revealed SOCS1 and TGFBR1 as direct targets of miR-142a-5p and miR-142a-3p, respectively, and overexpression of miRNA mimic sequences suppressed the expression of these target transcripts in lymphocytes. SOCS1 levels were also diminished in MS white matter and EAE spinal cords.

Conclusions

Our findings suggest that increased expression of miR-142 isoforms might be involved in the pathogenesis of autoimmune neuroinflammation by influencing T cell differentiation, and this effect could be mediated by interaction of miR-142 isoforms with SOCS1 and TGFBR-1 transcripts.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-017-0832-7) contains supplementary material, which is available to authorized users.

MicroRNA expression profiles in human CD3+ T cells following stimulation with anti-human CD3 antibodies

Background

Anti-CD3 therapy can induce immunosuppression by several non mutually exclusive mechanisms that have been proposed to explain the therapeutic effect the administration anti-CD3 mAb, but its immunoregulatory mechanism is still not completely clear. In T cells, microRNAs (miRNAs) regulate several pathways, including those associated with immune tolerance. Here, we report changes in miRNA expression in T cells following treatment with anti-human CD3 antibodies. Peripheral blood mononuclear cells were cultured in the presence of the monoclonal antibody OKT3 or a recombinant fragment of humanized anti-CD3. Following these treatments, the expression profiles of 31 miRNA species were assessed in T cells using TaqMan arrays.

Results

Eight of the tested miRNAs (miR-155, miR-21, miR-146a, miR-210, miR-17, miR-590-5p, miR-106b and miR-301a) were statistically significantly up- or down-regulated relative to untreated cells.

Conclusions

Stimulation of T cells with anti-human CD3 antibodies alters miRNA expression patterns, including of miRNA species associated with immune regulatory pathways.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-017-2442-y) contains supplementary material, which is available to authorized users.

TGF-β regulation of encephalitogenic and regulatory T cells in multiple sclerosis

Transforming growth factor beta (TGF-β) is a pleiotropic cytokine that has been shown to influence the differentiation and function of T cells. The role that TGF-β plays in immune-mediated disease, such as multiple sclerosis (MS), has become a major area of investigation since CD4⁺ T cells appear to be a major mediator of autoimmunity. This review provides an analysis of the literature on the role that TGF-β plays in the generation and regulation of encephalitogenic and regulatory T cells (Treg) in experimental autoimmune encephalomyelitis (EAE), an animal model of MS, as well as in T cells of MS patients. Since TGF-β plays a major role in the development and function of both CD4⁺ effector and Treg, which are defective in MS patients, recent studies have found potential mechanisms to explain the basis for these T-cell defects to establish a foundation for potentially modulating TGF-β signaling to restore normal T-cell function in MS patients.

miRNAs as biomarkers of neurodegenerative disorders

Neurodegenerative diseases (NDDs) are the result of progressive deterioration of neurons, ultimately leading to disabilities. There is no effective cure for NDDs at present; ongoing therapies are mainly aimed at treating the most bothersome symptoms. Since early treatment is crucial in NDDs, there is an urgent need for specific and sensitive biomarkers that can aid in early diagnosis of these disorders. Recently, altered expression of miRNAs has been implicated in several neurological disorders, including NDDs. miRNA expression has been extensively investigated in the cells, tissues and body fluids of patients with different types of NDDs. The aim of this review is to provide a comprehensive overview of miRNAs as biomarkers and therapeutic targets for NDDs.

Mir-223 regulates the number and function of myeloid-derived suppressor cells in multiple sclerosis and experimental autoimmune encephalomyelitis

Myeloid-derived cells play important modulatory and effector roles in multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells, composed of monocytic (MO) and polymorphonuclear (PMN) fractions, which can suppress T cell activities in EAE. Their role in MS remains poorly characterized. We found decreased numbers of circulating MDSCs, driven by lower frequencies of the MO-MDSCs, and higher MDSC expression of microRNA miR-223 in MS versus healthy subjects. To gain mechanistic insights, we interrogated the EAE model. MiR-223 knock out (miR-223^-/-) mice developed less severe EAE with increased MDSC numbers in the spleen and spinal cord compared to littermate controls. MiR-223^-/- MO-MDSCs suppressed T cell proliferation and cytokine production in vitro and EAE in vivo more than wild-type MO-MDSCs. They also displayed an increased expression of critical mediators of MDSC suppressive function, Arginase-1(Arg1), and the signal transducer and activator of transcription 3 (Stat3), which herein, we demonstrate being an miR-223 target gene. Consistently, MDSCs from MS patients displayed decreased STAT3 and ARG1 expression compared with healthy controls, suggesting that circulating MDSCs in MS are not only reduced in numbers but also less suppressive. These results support a critical role for miR-223 in modulating MDSC biology in EAE and in MS and suggest potential novel therapeutic applications.

Fluoxetine Increases the Expression of miR-572 and miR-663a in Human Neuroblastoma Cell Lines

Evidence suggests neuroprotective effects of fluoxetine, a selective serotonin reuptake inhibitor (SSRI), on the developed neurons in the adult brain. In contrast, the drug may be deleterious to immature or undifferentiated neural cells, although the mechanism is unclear. Recent investigations have suggested that microRNAs (miRNA) may be critical for effectiveness of psychotropic drugs including SSRI. We investigated whether fluoxetine could modulate expressions of neurologically relevant miRNAs in two neuroblastoma SK-N-SH and SH-SY5Y cell lines. Initial screening results revealed that three (miR-489, miR-572 and miR-663a) and four (miR-320a, miR-489, miR-572 and miR-663a) miRNAs were up-regulated in SK-N-SH cells and SH-SY5Y cells, respectively, after 24 hours treatment of fluoxetine (1–25 μM). Cell viability was reduced according to the dose of fluoxetine. The upregulation of miR-572 and miR-663a was consistent in both the SH-SY5Y and SK-N-SH cells, confirmed by a larger scale culture condition. Our data is the first in vitro evidence that fluoxetine could increase the expression of miRNAs in undifferentiated neural cells, and that putative target genes of those miRNAs have been shown to be involved in fundamental neurodevelopmental processes.

Analysis of microRNA and Gene Expression Profiles in Multiple Sclerosis: Integrating Interaction Data to Uncover Regulatory Mechanisms

MicroRNAs (miRNAs) have been reported to contribute to the pathophysiology of multiple sclerosis (MS), an inflammatory disorder of the central nervous system. Here, we propose a new consensus-based strategy to analyse and integrate miRNA and gene expression data in MS as well as other publically available data to gain a deeper understanding of the role of miRNAs in MS and to overcome the challenges posed by studies with limited patient sample sizes. We processed and analysed microarray datasets, and compared the expression of genes and miRNAs in the blood of MS patients and controls. We then used our consensus and integration approach to construct two molecular networks dysregulated in MS: a miRNA- and a gene-based network. We identified 18 differentially expressed (DE) miRNAs and 128 DE genes that may contribute to the regulatory alterations behind MS. The miRNAs were linked to immunological and neurological pathways, and we exposed let-7b-5p and miR-345-5p as promising blood-derived disease biomarkers in MS. The results suggest that DE miRNAs are more informative than DE genes in uncovering pathways potentially involved in MS. Our findings provide novel insights into the regulatory mechanisms and networks underlying MS.

Upregulation of CD4+T-Cell Derived MiR-223 in The Relapsing Phase of Multiple Sclerosis Patients

Objective

MicroRNAs (miRNA) are a class of non-coding RNAs which play key roles in post-transcriptional gene regulation. Previous studies indicate that miRNAs are dysregulated in patients with multiple sclerosis (MS). Th17 and regulatory T (Treg) cells are two subsets of CD4+T-cells which have critical functions in the onset and progression of MS. The current study seeks to distinguish fluctuations in expression of CD4+T-cell derived miR-223 during the relapsing-remitting (RR) phase of MS (RR-MS), as well as the expressions of Th17 and Treg cell markers.

Materials and Methods

This experimental study used real-time quantitative polymerase chain reaction (qRT-PCR) to evaluate CD4+ T cell derived miR-223 expression patterns in patients that experienced either of the RR-MS phases (n=40) compared to healthy controls (n=12), along with RNA markers for Th17 and Treg cells. We conducted flow cytometry analyses of forkhead box P3 (FOXP3) and RAR-related orphan receptor γt (RORγt) in CD4+T-cells. Putative and validated targets of miR-223 were investigated in the miRWalk and miRTarBase databases, respectively.

Results

miR-223 significantly upregulated in CD4+T-cells during the relapsing phase of RR-MS compared to the remitting phase (P=0.000) and healthy individuals (P=0.036). Expression of RORγt, a master transcription factor of Th17, upregulated in the relapsing phase, whereas FOXP3 upregulated in the remitting phase. Additionally, potential targets of miR-223, STAT1, FORKHEAD BOX O (FOXO1) and FOXO3 were predicted by in silico studies.

Conclusion

miR-223 may have a potential role in MS progression. Therefore, suppression of miR-223 can be proposed as an appropriate approach to control progression of the relapsing phase of MS.

Comprehensive evaluation of serum microRNAs as biomarkers in multiple sclerosis

Objective:

To identify circulating microRNAs (miRNAs) linked to disease stage and disability in multiple sclerosis (MS).

Methods:

Sera from 296 participants including patients with MS, other neurologic diseases (Alzheimer disease and amyotrophic lateral sclerosis), and inflammatory diseases (rheumatoid arthritis and asthma) and healthy controls (HCs) were tested. miRNA profiles were determined using LNA (locked nucleic acid)-based quantitative PCR. Patients with MS were categorized according to disease stage and disability. In the discovery phase, 652 miRNAs were measured in sera from 26 patients with MS and 20 HCs. Following this, significant miRNAs (p < 0.05) from the discovery set were validated using quantitative PCR in 58 patients with MS, 30 HCs, and in 74 samples from other disease controls (Alzheimer disease, amyotrophic lateral sclerosis, asthma, and rheumatoid arthritis).

Results:

We validated 7 miRNAs that differentiate patients with MS from HCs (p < 0.05 in both the discovery and validation phase); miR-320a upregulation was the most significantly changing serum miRNA in patients with MS. We also identified 2 miRNAs linked to disease progression, with miR-27a-3p being the most significant. Ten miRNAs correlated with the Expanded Disability Status Scale of which miR.199a.5p had the strongest correlation with disability. Of the 15 unique miRNAs we identified in the different group comparisons, 12 have previously been reported to be associated with MS but not in serum.

Conclusions:

Our findings identify circulating serum miRNAs as potential biomarkers to diagnose and monitor disease status in MS.

Classification of evidence:

This study provides Class III evidence that circulating serum miRNAs can be used as biomarker for MS.

Epigenetic Modifications and Therapy in Multiple Sclerosis

Breakthroughs in genetic studies, like whole human genome sequencing and genome-wide association studies (GWAS), have richened our knowledge of etiopathology of autoimmune diseases (AID) through discovery of genetic patterns. Nonetheless, the precise etiology of autoimmune diseases remains largely unknown. The lack of complete concordance of autoimmune disease in identical twins suggests that non-genetic factors also play a major role in determining disease susceptibility. Although there is no certain definition, epigenetics has been known as heritable alterations in gene function without changes in the nucleotide sequence. DNA methylation, histone modifications, and microRNA-associated gene expression suppression are the central mechanisms for epigenetic regulations. Multiple sclerosis (MS) is a disorder of the central nervous system (CNS), characterized by both inflammatory and neurodegenerative features. Although studies on epigenetic alterations in MS only began in the past decade, a mounting number of surveys suggest that epigenetic changes may be involved in the initiation and development of MS, probably through bridging the effects of environmental risk factors to genetics. Arming with clear understanding of epigenetic dysregulations underpins development of epigenetic therapies. Identifying agents inhibiting the enzymes controlling epigenetic modifications, particularly DNA methyltransferases and histone deacetylases, will be promising therapeutic tool toward MS. In the article underway, it is aimed to go through the recent progresses, attempting to disclose how epigenetics associates with the pathogenesis of MS and how can be used as therapeutic approach.

Meta-Analysis of Differential Connectivity in Gene Co-Expression Networks in Multiple Sclerosis

Differential gene expression analyses to investigate multiple sclerosis (MS) molecular pathogenesis cannot detect genes harboring genetic and/or epigenetic modifications that change the gene functions without affecting their expression. Differential co-expression network approaches may capture changes in functional interactions resulting from these alterations. We re-analyzed 595 mRNA arrays from publicly available datasets by studying changes in gene co-expression networks in MS and in response to interferon (IFN)-β treatment. Interestingly, MS networks show a reduced connectivity relative to the healthy condition, and the treatment activates the transcription of genes and increases their connectivity in MS patients. Importantly, the analysis of changes in gene connectivity in MS patients provides new evidence of association for genes already implicated in MS by single-nucleotide polymorphism studies and that do not show differential expression. This is the case of amiloride-sensitive cation channel 1 neuronal (ACCN1) that shows a reduced number of interacting partners in MS networks, and it is known for its role in synaptic transmission and central nervous system (CNS) development. Furthermore, our study confirms a deregulation of the vitamin D system: among the transcription factors that potentially regulate the deregulated genes, we find TCF3 and SP1 that are both involved in vitamin D3-induced p27Kip1 expression. Unveiling differential network properties allows us to gain systems-level insights into disease mechanisms and may suggest putative targets for the treatment.

MicroRNA Expression in the Glaucomatous Retina

PURPOSE

MicroRNAs are small, endogenous noncoding RNAs that modulate posttranscriptional gene expression. Although the contribution of microRNAs to the pathogenesis of glaucomatous damage is unknown, supporting evidence from central nervous system (CNS) research suggests they may play a role. It was therefore hypothesized that microRNAs known to be altered in CNS injury are also altered in experimental glaucoma.

METHODS

Intraocular pressure (IOP) was elevated in rats by unilateral injection of hypertonic saline and IOP monitored for 5 weeks. After rats were killed, retrobulbar optic nerve sections were graded for damage. MicroRNA was extracted from whole retinae of eyes with advanced nerve damage (n = 8) and from normal, noninjected control eyes (n = 8). Quantitative PCRs were performed using a panel of 17 microRNAs, reported from CNS research to be implicated in mechanisms also linked to glaucomatous damage. Computationally and experimentally derived gene targets were identified for the differentially expressed microRNAs. These were then integrated with existing gene array data. Functional interpretation was performed using the Molecular Signatures Database and DAVID Functional Annotation Clustering.

RESULTS

Eight microRNAs were significantly downregulated in glaucomatous retinae compared with controls (miR-181c, miR-497, miR-204, let-7a, miR-29b, miR-16, miR106b, and miR-25); miR-27a was significantly upregulated. Enrichment of targets associated with extracellular matrix/cell proliferation, immune system, and regulation of apoptosis were observed. Cholesterol homeostasis and mTORC-1 pathways showed reduced expression.

CONCLUSIONS

MicroRNAs are differentially expressed in retinae of eyes with advanced glaucomatous damage compared with normal controls. Integrating microRNA with gene expression data may improve understanding of the complex biological responses produced by chronically elevated IOP.

MicroRNAs targeting TGFβ signalling underlie the regulatory T cell defect in multiple sclerosis

Transforming growth factor beta (TGFβ) signalling is critical for regulatory T cell development and function, and regulatory T cell dysregulation is a common observation in autoimmune diseases, including multiple sclerosis. In a comprehensive miRNA profiling study of patients with multiple sclerosis naïve CD4 T cells, 19 differentially expressed miRNAs predicted to target the TGFβ signalling pathway were identified, leading to the hypothesis that miRNAs may be responsible for the regulatory T cell defect observed in patients with multiple sclerosis. Patients with multiple sclerosis had reduced levels of TGFβ signalling components in their naïve CD4 T cells. The differentially expressed miRNAs negatively regulated the TGFβ pathway, resulting in a reduced capacity of naïve CD4 T cells to differentiate into regulatory T cells. Interestingly, the limited number of regulatory T cells, that did develop when these TGFβ-targeting miRNAs were overexpressed, were capable of suppressing effector T cells. As it has previously been demonstrated that compromising TGFβ signalling results in a reduced regulatory T cell repertoire insufficient to control autoimmunity, and patients with multiple sclerosis have a reduced regulatory T cell repertoire, these data indicate that the elevated expression of multiple TGFβ-targeting miRNAs in naïve CD4 T cells of patients with multiple sclerosis impairs TGFβ signalling, and dampens regulatory T cell development, thereby enhancing susceptibility to developing multiple sclerosis.

Is It worth Considering Circulating microRNAs in Multiple Sclerosis?

New evidence has highlighted that miRNA production and trafficking can be dysregulated in both autoimmmune and neurological disorders. Multiple sclerosis (MS) in particular is an autoimmune pathology leading to neurodegeneration. Profiling studies performed on cells derived from MS patients have described a dysregulated network of miRNAs in both immune and neural cells. Interestingly, new evidence has emerged showing that circulating miRNAs are also dysregulated in MS body fluids, including plasma/serum and cerebrospinal fluid. This review summarizes the current scientific theories on the function of this altered circulating miRNA network. It builds up new insights about miRNA transfer mechanisms including extracellular vesicle trafficking involved in cell-to-cell communication and the possible physiopathological functions of these transfers in MS. Finally, this review proposes that monitoring altered miRNA expression levels could serve as a potential biomarker read-out of MS subtype and severity.

MicroRNAs and Bone Regeneration

Bone has multiple functions, both morphologically and physiologically, and it frequently features in the pathological condition, including fracture and osteoporosis. For bone regeneration therapy, the regulation of osteoblast differentiation is important. MicroRNA (miRNA)s are short noncoding RNA which regulate gene expression at the post-transcriptional level. MiRNAs play an important role not only in a variety of other cellular processes including differentiation, proliferation, and apoptosis but also in the pathogenesis of human diseases. Recently, miRNAs have been known to participate in osteoblast differentiation by regulating several signaling pathways including transcription factors. New insight into the mechanism during osteogenes is affected by miRNAs has been gained. Moreover, therapeutic trials for bone diseases including osteoporosis, fracture and bone defects targeting miRNAs have been examined in animal models. MiRNA therapy will enable development of a bone regeneration therapy.

Dicer and microRNA expression in multiple sclerosis and response to interferon therapy

Dysregulation of microRNA expression has been shown in multiple sclerosis (MS); however, the mechanisms underlying these changes, their response to therapy and the impact of microRNA changes in MS are not completely understood. Dicer mediates the cleavage of precursor microRNAs to mature microRNAs and is dysregulated in multiple pathologies. Having shown that interferons regulate Dicer in vitro, we hypothesized that MS patient IFNβ1a treatment could potentially alter Dicer expression. Dicer mRNA and protein levels, as well as microRNA expression, were determined in MS patient and healthy control PBL. Acute responses to IFNβ1a were assessed in 50 patients. We found that Dicer protein but not mRNA levels decreases in MS patients while both are selectively induced in patients responding well to IFNβ1a. Potential microRNA biomarkers for relapsing remitting multiple sclerosis (RRMS), secondary progressive multiple sclerosis (SPMS) and IFNβ1a response are described. Contrasts in Dicer and microRNA expression levels between patient populations may offer insight into mechanisms underlying disease courses and responses to IFNβ1a therapy. This work identifies Dicer regulation as both a potential mediator of MS pathology and a therapeutic target.

Evaluation of Immune Profiles and MicroRNA Expression Profiles in Peripheral Blood Mononuclear Cells of Long-Term Stable Liver Transplant Recipients and Recipients With Acute Rejection Episodes

OBJECTIVE

This study aimed to document the difference of immunophenotypes in peripheral blood mononuclear cells (PBMCs) between long-term stable liver transplant recipients and recipients with acute rejection. We also sought to identify whether there is any correlation between microRNA (miRNA) expression profile and the differential immunoprofile in these 2 groups to establish a specific miRNA biomarker to identify potential liver transplant recipients.

METHODS

PBMCs were isolated from 53 stable liver transplant recipients (STA group) and 15 liver transplant recipients with repeated biopsy-proven rejection episodes admitted to our hospital. Immunoprofiles were analyzed by means of flow cytometry. Analysis of miRNA expression in the PBMCs was performed by means of real-time polymerase chain reaction.

RESULTS

The immune profiling analysis showed increased frequency of peripheral natural killer cells and regulatory T cells in stable liver transplant recipients compared with the acute rejection recipients and healthy volunteers (P < .05). There was no significant difference in the immune cell levels (CD19(+) B cells, CD4(+) T cells, and CD8(+) T cells) in PBMCs among the transplant recipient groups and healthy control subjects. Three miRNAs, miR-18b, miR-340, and miR-106b, were up-regulated in the PBMCs of the STA recipients compared with recipients with acute rejection.

CONCLUSIONS

These results suggest that miR-18b, miR-340, and miR-106b, which regulate the expression of specific immunophenotypes, can be used as potential biomarkers to identify long-term stable liver transplant recipients from recipients with acute rejection.

Mutual interaction between BCL6 and microRNAs in T cell differentiation

The transcription factor B-cell CLL/lymphoma 6 (BCL6) and the regulatory factor microRNAs (miRNAs) are of great importance in the differentiation of T cell subsets. An increasing body of evidence has demonstrated that BCL6 and miRNAs can target one another and mutually adjust their expression in T cell subsets, such as T helper (Th)-2, Th17, CD8+ regulatory T (CD8+Treg) and T follicular helper (Tfh) cells. Here, we discuss the most recent advances and emerging concepts in how BCL6 and miRNAs regulate one another, and the effects of such mutual regulations on T cell subset differentiation.

Next-generation sequencing identifies altered whole blood microRNAs in neuromyelitis optica spectrum disorder which may permit discrimination from multiple sclerosis

Background

Neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) have a similar clinical phenotype but represent distinct diseases, requiring different therapies. MicroRNAs (miRNAs) are short non-coding RNAs whose expression profiles can serve as diagnostic biomarkers and which may be involved in the pathophysiology of neuroinflammatory diseases. Here, we analyzed miRNA profiles in serum and whole blood of patients with NMOSD and clinically isolated syndrome (CIS)/relapsing-remitting MS (RRMS) as well as healthy controls by next-generation sequencing (NGS).

Methods

MiRNA expression profiles were determined by NGS in sera of patients with aquaporin-4 antibody-positive NMOSD (n = 20), CIS/RRMS (n = 20), and healthy controls (n = 20) and in whole blood of patients with NMOSD (n = 11), CIS/RRMS (n = 60), and healthy controls (n = 43). Differentially expressed miRNAs were calculated by analysis of variance and t tests. All significance values were corrected for multiple testing. Selected miRNAs were validated in whole blood of patients with NMOSD (n = 18) and CIS/RRMS (n = 19) by quantitative real-time polymerase chain reaction (qRT-PCR).

Results

None of 261 miRNAs detected in serum but 178 of 416 miRNAs detected in whole blood showed significantly different expression levels among the three groups. Pairwise comparisons revealed 115 (NMOSD vs. CIS/RRMS), 141 (NMOSD vs. healthy controls), and 44 (CIS/RRMS vs. healthy controls) miRNAs in whole blood with significantly different expression levels. qRT-PCR confirmed different expression levels in whole blood of patients with NMOSD and CIS/RRMS for 9 out of 10 exemplarily chosen miRNAs. In silico enrichment analysis demonstrated an accumulation of altered miRNAs in NMOSD in particular in CD15⁺ cells (i.e., neutrophils and eosinophils).

Conclusions

This study identifies a set of miRNAs in whole blood, which may have the potential to discriminate NMOSD from CIS/RRMS and healthy controls. In contrast, miRNA profiles in serum do not appear to be promising diagnostic biomarkers for NMOSD. Enrichment of altered miRNAs in CD15⁺ neutrophils and eosinophils, which were previously implicated in the pathophysiology of NMOSD, suggests that miRNAs could be involved in the regulation of these cells in NMOSD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-015-0418-1) contains supplementary material, which is available to authorized users.

Acceleration of healing of the medial collateral ligament of the knee by local administration of synthetic microRNA-210 in a rat model

Background

Injury to the medial collateral ligament (MCL) of the knee joint is the most common ligament injury of the knee. Ligament healing generally takes a long time. Micro-ribonucleic acid (miRNA) is one of the noncoding RNAs and plays a crucial role in physiological function; miRNA (miR)-210 is known as a potent factor of angiogenesis, which is an important initiator of ligament healing. The purpose of this study is to examine the effect of local injection of double-stranded (ds) miR-210 on the healing of the MCL of rat knee joint.

Methods

MCLs of Sprague-Dawley rats were cut transversely. After the fascia and skin were sutured, dsmiR-210 or control dsRNA was injected into the injured site of MCL. At 2 weeks and 4 weeks, histological analysis and immunofluorescence staining of vascular endothelial growth factor, isolectin B4, collagen type 1, and Ki67 as well as a mechanical test were performed. Analysis of complementary deoxyribonucleic acid (cDNA) microarray data was performed at 1 week.

Results

Histological analysis showed that parallel fibres in the injured site were organised at 2 weeks and became thicker at 4 weeks in the miR-210-treated group, whereas the injured site in controls was filled with loose fibrous tissues and was thinner than that in the miR-210-treated group. The number of blood vessels in the miR-210-treated group was significantly higher than that in controls (p < 0.05), and vascular endothelial growth factor, Ki67, and collagen type 1 in the miR-210-treated group were intensely expressed in the repaired site as compared to the control group. The mechanical test indicated that the ultimate failure load in the miR-210-treated group was significantly higher than that in the control group at 2 weeks. The cDNA microarray analysis showed significant upregulation of genes related to cell proliferation and cell differentiation, and genes involved in negative regulation of apoptosis.

Conclusion

This study showed that local injection of dsmiR-210 could accelerate MCL healing in rat, which is likely due to stimulation of angiogenesis at the healing site.

Integrative computational mRNA-miRNA interaction analyses of the autoimmune-deregulated miRNAs and well-known Th17 differentiation regulators: An attempt to discover new potential miRNAs involved in Th17 differentiation

Th17 cells are a lineage of CD4(+) T helper cells in immune system which differentiate from naïve CD4(+) T cells and have demonstrated to play a critical role in the pathogenesis of different autoimmune disorders. miRNAs are a novel group of non-coding RNAs which participate in post-transcriptional regulation of gene expression mostly by pairing with 3'UTR of their mRNA targets and inhibition of its translation. It has been demonstrated that miRNAs function in various cellular processes such as differentiation, proliferation, and apoptosis. By now, several signaling pathways and their downstream positive and negative regulators involve in Th17 differentiation have been discovered. Several studies have reported the aberrant miRNA expression profile in patients with autoimmune disease called autoimmune-deregulated miRNAs. Here, using integrative miRwalk database which assembles the data gathered from ten different bioinformatics databases designed to predict miRNA-target interaction, we analyzed possible targeting effect of "autoimmune-deregulated miRNAs" on prominent positive and negative regulators of Th17 differentiation. Our resulting mRNA-miRNA network simply nominated several miRNAs with strong possibility which probably may have inducing (miR-27b, miR-27a, miR-30c, miR-1, and miR-141) or inhibitory (miR-20b, miR-93, miR-20a, miR-152, miR-21, and miR-106a) role in Th17 differentiation by targeting negative or positive regulators of Th17 differentiation, respectively.

Targeted Stage-Specific Inflammatory microRNA Profiling in Urine During Disease Progression in Experimental Autoimmune Encephalomyelitis: Markers of Disease Progression and Drug Response

Recently, microRNAs (miRNAs) have been implicated in regulating neuroinflammatory and demyelinative responses in multiple sclerosis (MS) and its mouse model of experimental autoimmune encephalomyelitis (EAE). miRNAs have also been studied as biomarkers of disease pathology and drug-response in MS. However, no complete miRNA profiling at various stages of EAE disease has been examined, especially in the urine. We carried out a systematic analysis of miRNAs in the urine exosomes as well as in the plasma and spinal cord at pre-onset, onset and peak stages of EAE established in the chronic B6 mice model. For the first time, we provide evidence that urine exosomes can be a specific and sensitive source of miRNA biomarkers for all 3 stages of EAE disease. In a significant observation, we observed that miR-155-5p expression increased in urine exosomes, plasma and spinal cord 6 days before the onset of disease, suggesting its early involvement in the pathology of EAE disease. We also analyzed the effect of Glatiramer acetate (GA; copaxone) treatment, an approved treatment for MS patients, in modulating miRNA expression at the peak of EAE disease. We identified miR-155-5p, miR-27a-3p, miR-9-5p and miR-350-5p as putative GA-treatment responsive miRNA biomarkers. Since, EAE is a mainly CD4 cells mediated disease, we also examined the above set of miRNAs and found to be significantly altered in T cells polarized to Th1 and Th17 phenotype, similar to urine exosomes. Thus, urine exosome miRNAs hold the potential to be defined as novel accessible stage-specific biomarkers of EAE (MS) disease as well as treatment response.

Platelet MicroRNAs: An Overview

MicroRNAs (miRNAs) are short ~22-nucleotide noncoding RNA that have been found to influence the expression of many genes and cellular processes by either repressing translation or degrading messenger RNA transcripts. Platelet miRNA expression has been shown to be perturbed during ex vivo storage of platelets and in platelet-associated disorders. Although bioinformatics-based miRNA target predictions have been established, direct experimental validation of the role of miRNAs in platelet biology has been rather slow. Target prediction studies are, nonetheless, valuable in directing the design of appropriate experiments to test specific miRNA:messenger RNA interactions relevant to the underlying mechanisms of platelet function in general and in disease as well as in ex vivo storage-associated "storage lesions," a collective term used to include physiologic, biochemical, and morphologic changes that occur in stored platelets. This brief review will focus on emerging human platelet miRNA studies to emphasize their potential role relevant to transfusion medicine field in terms of regulating platelet signaling pathways, markers of platelet associated disorders, and remote impactors of gene expression (intercellular biomodulators) as well as potential platelet quality markers of storage and pathogen reduction treatments.

MicroRNAs: Emerging Regulators of Immune-Mediated Diseases

MicroRNAs (miRNAs) represent the most abundant class of regulators of gene expression in humans: they regulate one-third of human protein-coding genes. These small noncoding ∼22-nucleotides (nt)-long RNAs originate by multistep process from miRNA genes localized in the genomic DNA. To date, more than 1420 miRNAs have been identified in humans (miRBase v17). The main mechanism of miRNA action is the posttranscriptional regulation via RNA interference with their target mRNAs. The majority of target mRNAs (more than 80%) undergo degradation after recognition by complementary miRNA; the translational inhibition with little or no influence on mRNA levels has been also reported. Each miRNA may suppress multiple mRNA targets (average ∼200), and at the same time, one mRNA can be targeted by many miRNAs enabling to control a spectrum wide range of cellular processes. Recently, the role of miRNAs in the development of immune cells and the maintenance of immune system homeostasis gained attention, and the involvement of miRNAs in the pathogenesis of several immune system diseases has emerged. This review focuses on the role of miRNAs in autoimmune disorders (systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, inflammatory bowel disease and psoriasis), inflammatory pathologies of distinct organ (atherosclerosis, osteoarthritis and atopic eczema) and/or systemic locations such as allergy. The role of miRNAs, their predicted and known mRNA targets and description of their actions in physiological immune reactions and in the pathological processes ongoing in immune-mediated human disorders will be discussed. Finally, miRNA-based diagnostics and therapeutic potentials will be highlighted.

Peripheral blood biomarkers in multiple sclerosis

Multiple sclerosis is the most common autoimmune disorder affecting the central nervous system. The heterogeneity of pathophysiological processes in MS contributes to the highly variable course of the disease and unpredictable response to therapies. The major focus of the research on MS is the identification of biomarkers in biological fluids, such as cerebrospinal fluid or blood, to guide patient management reliably. Because of the difficulties in obtaining spinal fluid samples and the necessity for lumbar puncture to make a diagnosis has reduced, the research of blood-based biomarkers may provide increasingly important tools for clinical practice. However, currently there are no clearly established MS blood-based biomarkers. The availability of reliable biomarkers could radically alter the management of MS at critical phases of the disease spectrum, allowing for intervention strategies that may prevent evolution to long-term neurological disability. This article provides an overview of this research field and focuses on recent advances in blood-based biomarker research.

Ultraviolet C radiation influences the robustness of RNA integrity measurement

The analytical and clinical validity of analyses of RNA samples destined for clinical diagnosis and therapeutic management is directly impacted by RNA quality. RNA is affected by heat, enzymatic degradation, and Ultraviolet (UV) light. RNA from three eukaryotic cell lines was degraded by heat, RNase, or UV light. RNA integrity values obtained with the benchmark Agilent Bioanalyzer 2100 system were compared with those from the more recent QIAxcel Advanced system. The application of this novel method has allowed us to unravel differences between RNA biophysical and biochemical degradation modes. Agilent RNA integrity number (RIN) and QIAxcel RIS were comparable in heat-degraded and RNase III-degraded RNA. Agilent RIN and QIAxcel RIS were comparable at a RIN decision level of 7 in UV-degraded RNA but not overall. The QIAxcel RIS method was more precise than Agilent RIN for RIN<8, while the inverse was true for RIN≥8. Greater degradation of mRNA and rRNA in UV-damaged samples hampered the Agilent RIN calculation algorithm. Overall, RIS was more robust than RIN for assessing RNA integrity. The ΔΔCt-values for heat- and UV-degraded RNA samples showed slightly higher correlation with RIS than with RIN. RNA integrity can be used to categorize RNA samples for suitability for downstream gene expression analyses, independently of the RNA degradation mechanism. The new method QIAxcel is more robust and therefore allows more accurate categorization of compromised RNA samples.

MicroRNA regulation of lymphocyte tolerance and autoimmunity

Understanding the cell-intrinsic cues that permit self-reactivity in lymphocytes, and therefore autoimmunity, requires an understanding of the transcriptional and posttranscriptional regulation of gene expression in these cells. In this Review, we address seminal and recent research on microRNA (miRNA) regulation of central and peripheral tolerance. Human and mouse studies demonstrate that the PI3K pathway is a critical point of miRNA regulation of immune cell development and function that affects the development of autoimmunity. We also discuss how miRNA expression profiling in human autoimmune diseases has inspired mechanistic studies of miRNA function in the pathogenesis of multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, type 1 diabetes, and asthma.

miRNA in multiple sclerosis: search for novel biomarkers

A major challenge in multiple sclerosis (MS) is to develop biomarkers that could help in understanding individual MS patients, i.e. whether they are a responder or non-responder to therapy, which medicine is more effective, and the degree to which they may be entering the progressive phase of disease. In the last few years, a lot of attention has been drawn toward identification of diagnostic, prognostic, process-specific, and treatment-related biomarkers for MS. In this review, we will focus on the micro RNAs (miRNAs) as potential candidates for MS biomarkers.

Natalizumab restores aberrant miRNA expression profile in multiple sclerosis and reveals a critical role for miR-20b

Objective

To identify microRNAs (miRNAs) regulated by anti-α4 integrin monoclonal antibody therapy (natalizumab) in the peripheral blood of patients with relapsing-remitting (RR) multiple sclerosis (MS) and to confirm their role in experimental settings in vivo.

Methods

In a longitudinal study of 17 RR-MS patients, we investigated blood miRNA expression profiles at baseline and after 1 year of natalizumab therapy by microarray technique and quantitative PCR validation. We compared the baseline expression profiles of these patients to those of 18 age- and sex-matched healthy controls. We confirmed the contribution of resulting candidate miRNAs in an animal model of MS, experimental autoimmune encephalomyelitis (EAE) induced by adoptive transfer of proteolipid protein (PLP)_139–151-activated lymphocytes in SJL/J mice or by active immunization of miR-106a∼363-deficient C57BL/6 mice (or wildtype litter mates) with myelin oligodendrocyte glycoprotein (MOG)_35–55.

Results

Our longitudinal analysis revealed that miR-18a, miR-20b, miR-29a, and miR-103 were upregulated and predominantly expressed by CD4⁺ T cells, whereas miR-326 was downregulated upon natalizumab treatment. A comparison of untreated RR-MS patients at baseline with healthy controls revealed that the four natalizumab-upregulated targets were initially downregulated in MS. All confirmed targets showed disease-dependent expression in splenocytes of mice suffering from EAE. Genetic deletion of the miRNA cluster miR-106a∼363 (containing natalizumab-regulated miR-20b) resulted in a more severe EAE course and an in vivo upregulation of the miR-20b target genes rorgt, stat3, and vegfa.

Interpretation

Our study indicates that natalizumab restores dysregulated miRNA patterns in MS and reveals the contribution of miR-20b in autoimmune demyelination in vivo.

Integrative analysis of mRNA and miRNA array data reveals the suppression of retinoic acid pathway in regulatory T cells of Graves' disease

CONTEXT

It is well known that regulatory T cells (Tregs) are abnormal in Graves' disease (GD) and play crucial roles in the breakdown of immune tolerance and GD development. However, there are controversies about whether the quantity and/or function of Tregs is aberrant in GD. The molecular mechanism of Tregs abnormality and its effects on GD development was still unclear, until now.

OBJECTIVE

MiRNAs play important roles in the function and development of the immune system including Tregs. To reveal the Tregs abnormality and its molecular mechanism in GD, we systematically studied the quantity and immunosuppressive function as well as the differential expression profiles of miRNA and mRNA of Tregs in newly diagnosed patients with GD using TaqMan miRNA array and mRNA microarray.

RESULTS

Our results showed that the quantity and immunosuppressive function of Tregs in initial patients with GD was significantly decreased. More importantly, the retinoic acid (RA) pathway was markedly suppressed and its agonist, all-trans retinoic acid, could notably improve the quantity and immunosuppressive function of Tregs from patients with GD in vitro. In addition, many other pathways including protein ubiquitination and circadian rhythm were also significantly regulated in Tregs of GD.

CONCLUSIONS

This integrative study first revealed the expression profiles of mRNA/miRNA in Tregs of initial GD and RA pathway might play important roles in GD development. Our results implied that all-trans RA, which had been used for a long time in the clinical setting, had potential value in the treatment of GD and was worthy of additional study.

Intra-articular injection of synthetic microRNA-210 accelerates avascular meniscal healing in rat medial meniscal injured model

Introduction

The important functions of the meniscus are shock absorption, passive stabilization and load transmission of the knee. Because of the avascularity of two-thirds of the meniscal center region, the treatment of tears in this area is hard. Recently, microRNAs have been proven to play an important role in the pathogenesis of diseases. We focused on microRNA (miR)-210, which plays a wide spectrum of roles comprising mitochondrial metabolism, angiogenesis, DNA repair and cell survival. This study aimed to investigate the effect of intra-articular injection of synthetic miR-210 on the injured meniscus in the avascular zone.

Methods

The middle segments of the medial meniscus of Spraque Dawley rats were incised longitudinally with a scalpel. An intra-articular injection of double-stranded (ds) miR-210 (for control group using control dsRNA) with atelocollagen was administered immediately after injury. Four weeks and 12 weeks after the injection, we conducted a histologic evaluation, immunohistochemical evaluation and Real-time PCR analysis. In vitro, the inner meniscus and synovial cells were isolated from rat knee joint, and were transfected with ds miR-210 or control dsRNA. Real-time PCR and immunohistochemical evaluations were performed.

Results

Twenty-four hours after the injection, FAM (Fluorescein amidite) labeled miR-210 was observed in the cells around the injured site. Four weeks after the injection, the injured site of the miR-210 group was filled with repaired tissue while that of the control was not repaired. In gene expression analysis of the meniscus, the expression of miR-210, Collagen type 2 alpha 1 (Col2a1), Vascular endothelial growth factor (VEGF), and Fibroblast growth factor-2 (FGF2) in the miR-210 group was significantly higher than that in the control. At 12 weeks, the intra-articular injection of miR-210 had healed the injured site of the meniscus and had prevented articular cartilage degeneration. In vitro, miR-210 upregulated Col2a1 expression in the meniscus cells and VEGF and FGF2 expression in the synovial cells.

Conclusions

An intra-articular injection of ds miR-210 was effective in the healing of the damaged white zone meniscus through promotion of the collagen type 2 production from meniscus cells and through upregulated of VEGF and FGF2 from synovial cells.