miR-10b-5p is a novel Th17 regulator present in Th17 cells from ankylosing spondylitis

The Role of H3K27me3-Mediated Th17 Differentiation in Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a common chronic progressive inflammatory autoimmune disease. T helper 17 (Th17) cells are the major effector cells mediating AS inflammation. Histone 3 Lys 27 trimethylation (H3K27me3) is an inhibitory histone modification that silences gene transcription and plays an important role in Th17 differentiation. The objective of this study was to investigate the expression of H3K27me3 in patients with AS and to explore its epigenetic regulation mechanism of Th17 differentiation during AS inflammation. We collected serum samples from 45 patients with AS at various stages and 10 healthy controls to measure their Interleukin-17 (IL-17) levels using ELISA. A quantitative polymerase chain reaction was used to quantify the mRNA levels of RORc and the signaling molecules of the JAK2/STAT3 pathway, JMJD3, and EZH2. Additionally, Western blot analysis was performed to quantify the protein levels of H3K27me3, RORγt, JAK2, STAT3, JMJD3, and EZH2 in cell protein extracts. The results showed that H3K27me3 expression in peripheral blood mononuclear cells (PBMCs) was significantly lower in patients with active AS compared to both the normal control groups and those with stable AS. Moreover, a significant negative correlation was observed between H3K27me3 expression and the characteristic transcription factor of Th17 differentiation, RORγt. We also discovered that patients with active AS exhibited significantly higher levels of JMJD3, an inhibitor of H3K27 demethylase, compared to the normal control group and patients with stable AS, while the expression of H3K27 methyltransferase (EZH2) was significantly lower. These findings suggest that H3K27me3 may be a dynamic and important epigenetic modification in AS inflammation, and JMJD3/EZH2 regulates the methylation level of H3K27me3, which may be one of the key regulatory factors in the pathogenesis of AS. These findings contribute to our understanding of the role of epigenetics in AS and may have implications for the development of novel therapeutic strategies for AS.

Dysregulated Non-Coding RNA Expression in T Cells from Patients with Ankylosing Spondylitis Contributes to Its Immunopathogenesis

Ankylosing spondylitis (AS) is a chronic inflammatory disorder characterized by inflammatory back pain and bony fusion of vertebral joints. Genetic associations and environmental factors have been proposed to explain the immunopathogenesis of AS. In the past few years, there have been major advances in understanding T cell dysfunction in AS. Clinically, targeting interleukin-17A, a major cytokine secreted by T helper 17 cells, has been approved for treating patients with active AS. Non-coding RNAs (ncRNAs) are RNA transcripts that do not translate into proteins. The ncRNAs regulate both innate and adaptive immunity and participate in the pathogenesis of autoimmune diseases, including AS. The main purpose of this article is to review the up-to-date studies investigating the aberrant expression of ncRNAs in T cells from patients with AS and to summarize their roles in its pathogenesis. After searching PubMed for studies published between January 2013 and June 2024, nine studies investigating the expression of ncRNAs in AS T cells were included. We found that aberrantly expressed ncRNAs in AS T cells could cause abnormal cytokine release, cell signaling abnormalities, and dysregulated cell proliferation and death, which contribute to the immunopathogenesis of AS. We discussed some limitations of these studies and suggested several research fields for further investigation.

The Mechanism of "Treating Different Diseases with the Same Treatment" by Qiangji Jianpi Decoction in Ankylosing Spondylitis Combined with Inflammatory Bowel Disease: A Comprehensive Analysis of Multiple Methods

Background

Ankylosing spondylitis (AS) and inflammatory bowel disease (IBD) are prevalent autoimmune disorders that often co-occur, posing significant treatment challenges. This investigation adopts a multidisciplinary strategy, integrating bioinformatics, network pharmacology, molecular docking, and Mendelian randomization, to elucidate the relationship between AS and IBD and to investigate the potential mechanisms of traditional Chinese medicine formulations, represented by Qiangji Jianpi (QJJP) decoction, in treating these comorbid conditions.

Methods

We utilized databases to pinpoint common targets among AS, IBD, and QJJP decoction's active compounds through intersection analysis. Through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, we mapped a network in Cytoscape, isolating critical targets. Molecular docking with AutoDock validated the affinity between targets and compounds. ROC analysis and dataset validation assessed diagnostic performance, while Gene Set Enrichment Analysis (GSEA) offered pathway insights. Mendelian randomization explored the AS-IBD causal relationship.

Results

Screening identified 105 targets for QJJP decoction, 414 for AS, and 2420 for IBD, with 85 overlapping. These targets predominantly participate in organismal responses and DNA transcription factor binding, with a significant cellular presence in the endoplasmic reticulum and vesicle lumen. Molecular docking, facilitated by Cytoscape, confirmed IL1A, IFNG, TGFB1, and EDN1 as critical targets, with IFNG demonstrating diagnostic potential through GEO dataset validation. The integration of GSEA with network pharmacology highlighted the therapeutic significance of the relaxin, osteoclast differentiation, HIF-1, and AGE-RAGE signaling pathways in QJJP decoction's action. Mendelian randomization analysis indicated a positive causal relationship between IBD and AS, pinpointing rs2193041 as a key SNP influencing IFNG.

Conclusion

Based on the principle of "treating different diseases with the same method" in traditional Chinese medicine theory, we explored the intricate mechanisms through which QJJP decoction addresses AS and IBD comorbidity. Our research spotlighted the pivotal role of the IFNG gene. IFNG emerges not only as a key therapeutic target but also assumes significance as a potential diagnostic biomarker through its genetic underpinnings. This investigation establishes a solid base for subsequent experimental inquiries. Our findings introduce novel approaches for incorporating traditional Chinese medicine into the treatment of AS-IBD comorbidity, setting the stage for groundbreaking research directions.

Reduced expression of miRNAs as potential biomarkers in axial spondyloarthritis

OBJECTIVE

This study aimed to investigate the value of miR-29a-3p, miR-27a, miR126-3p, miR-146a-5p, miR-625-3p, miR-130a, miR-32, miR-218, miR-131, and miR5196 in the diagnosis of axial spondyloarthritis and to determine whether there is a difference in miRNA expression levels between radiographic axial spondyloarthritis and non-radiographic axial spondyloarthritis, as well as the relationship between miRNA expression levels, disease activity, and uveitis history.

METHODS

This study included 50 patients with axial spondyloarthritis (25 with radiographic axial spondyloarthritis and 25 with non-radiographic axial spondyloarthritis) and 25 healthy individuals. The fold change of miRNA expression for each miRNA was calculated using the 2-ΔΔCt method.

RESULTS

The expression of all miRNAs except miR-130a was downregulated in axial spondyloarthritis patients (miR-27a: fold regulation: -11.21, p<0.001; miR-29a-3p: fold regulation: -2.63, p<0.001; miR-32: fold regulation: -2.94, p=0.002; miR-126-3p: fold regulation -10.94, p<0.001; miR-132: fold regulation: -2.18, p<0.001; miR-146-5p: fold regulation: -9.78, p<0.001; miR-218: fold regulation: -2.65, p<0.001; miR-625-3p: fold regulation: -2.01, p=0.001; miR-5196-3p: fold regulation: -7.04, p<0.001). The expression levels of these miRNAs did not differ significantly between non-radiographic axial spondyloarthritis and radiographic axial spondyloarthritis patients (p>0.05 for all).

CONCLUSION

Particularly, miR-27a, miR-126-3p, miR-146-5p, and miR-5196-3p were found to be substantially downregulated in both non-radiographic axial spondyloarthritis and radiographic axial spondyloarthritis patients, suggesting their potential as diagnostic biomarkers for axial spondyloarthritis.

miRNAs dysregulation in ankylosing spondylitis: A review of implications for disease mechanisms, and diagnostic markers

Epigenetic processes, including non-coding RNA, histone modifications, and DNA methylation, play a vital role in connecting the environment to the development of a disorder, especially when there is a favorable genetic background. Ankylosing Spondylitis (AS) is a chronic type of spinal arthritis that highlights the significance of epigenetics in diseases related to autoimmunity and inflammation. MicroRNAs (miRNAs) are small non-coding RNAs that are involved in both normal and aberrant pathological and physiological gene expression. This study focuses on the pathophysiological pathways to clarify the role of miRNAs in AS. We have conducted a thorough investigation of the involvement of miRNAs in several processes, including inflammation, the production of new bone, T-cell activity, and the regulation of pathways such as BMP, Wnt, and TGFβ signaling. Undoubtedly, miRNAs play a crucial role in enhancing our comprehension of the pathophysiology of AS, and their promise as a therapeutic strategy is quickly expanding.

A potential role of protein extractions from Metagonimus yokogawai in amelionating inflammation in patients with ankylosing spondylitis

Helminth infections and their components has been recognized to have a positive impact on the immune system. This study aimed to investigate the potential of Metagonimus yokogawai-derived proteins (MYp) to provide protection against ankylosing spondylitis (AS) through modulation of immune responses. The cytotoxicity of MYp at various doses was first assessed using MTS and flow cytometry. Peripheral blood mononuclear cells (PBMCs) were collected from AS patients, and the production of inflammatory cytokines was analyzed through flow cytometry. In the experiments with SKG mice, MYp or vehicle was administered and inflammation was evaluated through immunohistochemistry and enzyme-linked immunosorbent assay. The results showed that MYp did not decrease cell viability of PBMCs even after 48 h. Additionally, the frequencies of IFN-γ and IL-17A producing cells were significantly reduced after MYp treatment in the PBMC cultures. Furthermore, MYp treatment significantly suppressed arthritis and enthesitis in the SKG mouse model. The results suggest the first evidence that MYp can effectively alleviate clinical symptoms and restore cytokine balance in patients with AS.

Role of MicroRNAs in Inflammatory Joint Diseases: A Review

Inflammatory arthritis commonly initiates in the soft tissues lining the joint. This lining swells, as do the cells in it and inside the joint fluid, producing chemicals that induce inflammation signs such as heat, redness, and swelling. MicroRNA (miRNA), a subset of non-coding small RNA molecules, post-transcriptionally controls gene expression by targeting their messenger RNA. MiRNAs modulate approximately 1/3 of the human genome with their multiple targets. Recently, they have been extensively studied as key modulators of the innate and adaptive immune systems in diseases such as allergic disorders, types of cancer, and cardiovascular diseases. However, research on the different inflammatory joint diseases, such as rheumatoid arthritis, gout, Lyme disease, ankylosing spondylitis, and psoriatic arthritis, remains in its infancy. This review presents a deeper understanding of miRNA biogenesis and the functions of miRNAs in modulating the immune and inflammatory responses in the above-mentioned inflammatory joint diseases. According to the literature, it has been demonstrated that the development of inflammatory joint disorders is closely related to different miRNAs and their specific regulatory mechanisms. Furthermore, they may present as possible prognostic and diagnostic biomarkers for all diseases and may help in developing a therapeutic response. However, further studies are needed to determine whether manipulating miRNAs can influence the development and progression of inflammatory joint disorders.

Challenges and promise of targeting miRNA in rheumatic diseases: a computational approach to identify miRNA association with cell types, cytokines, and disease mechanisms

MicroRNAs (miRNAs) are small non-coding RNAs that alter the expression of target genes at the post-transcriptional level, influencing diverse outcomes in metabolism, cell differentiation, proliferation, cell survival, and cell death. Dysregulated miRNA expression is implicated in various rheumatic conditions, including ankylosing spondylitis (AS), gout, juvenile idiopathic arthritis (JIA), osteoarthritis (OA), psoriatic arthritis, rheumatoid arthritis (RA), Sjogren's syndrome, systemic lupus erythematosus (SLE) and systemic sclerosis. For this review, we used an open-source programming language- PowerShell, to scan the massive number of existing primary research publications on PubMed on miRNAs in these nine diseases to identify and count unique co-occurrences of individual miRNAs and the disease name. These counts were used to rank the top seven most relevant immuno-miRs based on their research volume in each rheumatic disease. Individual miRNAs were also screened for publication with the names of immune cells, cytokines, and pathological processes involved in rheumatic diseases. These occurrences were tabulated into matrices to identify hotspots for research relevance. Based on this information, we summarize the basic and clinical findings for the top three miRNAs - miR-146, miR-155, and miR-21 - whose relevance spans across multiple rheumatic diseases. Furthermore, we highlight some unique miRNAs for each disease and why some rheumatic conditions lack research in this emerging epigenetics field. With the overwhelming number of publications on miRNAs in rheumatic diseases, this review serves as a 'relevance finder' to guide researchers in selecting miRNAs based on the compiled existing knowledge of their involvement in disease pathogenesis. This approach applies to other disease contexts with the end goal of developing miRNA-based therapeutics.

T cells in the pathogenesis of axial spondyloarthritis

Axial spondyloarthritis (axSpA) is the prototype of the spondyloarthritis spectrum. The involvement of T cells in its pathogenesis has long been suspected on the basis of the association with the major histocompatibility complex I molecule HLA-B27 and the pivotal role of interleukin 17 in the inflammatory mechanisms associated with the disease. Moreover, the presence of unconventional or "innate-like" T cells within the axial enthesis suggests an important role for these cells in the pathophysiology of the disease. In this review, we describe the characteristics and the interleukin 17 secretion capacity of the T-cell subsets identified in axSpA. We discuss the genetic and epigenetic mechanisms that support the alteration of T-cell functions and promote their activation in axSpA. We also discuss recent data on T cells that could explain the extra-articular manifestations of the SpA spectrum.

Proteomic and genomic profiling of plasma exosomes from patients with ankylosing spondylitis

INTRODUCTION

Recent advances in understanding the biology of ankylosing spondylitis (AS) using innovative genomic and proteomic approaches offer the opportunity to address current challenges in AS diagnosis and management. Altered expression of genes, microRNAs (miRNAs) or proteins may contribute to immune dysregulation and may play a significant role in the onset and persistence of inflammation in AS. The ability of exosomes to transport miRNAs across cells and alter the phenotype of recipient cells has implicated exosomes in perpetuating inflammation in AS. This study reports the first proteomic and miRNA profiling of plasma-derived exosomes in AS using comprehensive computational biology analysis.

METHODS

Plasma samples from patients with AS and healthy controls (HC) were isolated via ultracentrifugation and subjected to extracellular vesicle flow cytometry analysis to characterise exosome surface markers by a multiplex immunocapture assay. Cytokine profiling of plasma-derived exosomes and cell culture supernatants was performed. Next-generation sequencing was used to identify miRNA populations in exosomes enriched from plasma fractions. CD4+ T cells were sorted, and the frequency and proliferation of CD4+ T-cell subsets were analysed after treatment with AS-exosomes using flow cytometry.

RESULTS

The expression of exosome marker proteins CD63 and CD81 was elevated in the patients with AS compared with HC (q<0.05). Cytokine profiling in plasma-derived AS-exosomes demonstrated downregulation of interleukin (IL)-8 and IL-10 (q<0.05). AS-exosomes cocultured with HC CD4+ T cells induced significant upregulation of IFNα2 and IL-33 (q<0.05). Exosomes from patients with AS inhibited the proliferation of regulatory T cells (Treg), suggesting a mechanism for chronically activated T cells in this disease. Culture of CD4+ T cells from healthy individuals in the presence of AS-exosomes reduced the proliferation of FOXP3+ Treg cells and decreased the frequency of FOXP3+IRF4+ Treg cells. miRNA sequencing identified 24 differentially expressed miRNAs found in circulating exosomes of patients with AS compared with HC; 22 of which were upregulated and 2 were downregulated.

CONCLUSIONS

Individuals with AS have different immunological and genetic profiles, as determined by evaluating the exosomes of these patients. The inhibitory effect of exosomes on Treg in AS suggests a mechanism contributing to chronically activated T cells in this disease.

Microbiota-assisted therapy for systemic inflammatory arthritis: advances and mechanistic insights

Research on the influence of gut microbiota on systemic inflammatory arthritis has exploded in the past decade. Gut microbiota changes may be a crucial regulatory component in systemic inflammatory arthritis. As a result of advancements in the field, microbiota-assisted therapy has evolved, but this discipline is still in its infancy. Consequently, we review the limitations of current systemic inflammatory arthritis treatment, analyze the connection between the microbiota and arthritis, and summarize the research progress of microbiota regulating systemic inflammatory arthritis and the further development aspects of microbiota-assisted therapy. Finally, the partial mechanisms of microbiota-assisted therapy of systemic inflammatory arthritis are being discussed. In general, this review summarizes the current progress, challenges, and prospects of microbiota-assisted therapy for systemic inflammatory arthritis and points out the direction for the development of microbiota-assisted therapy in the future.

Circulating miRNAs Are Associated with Inflammation Biomarkers in Children with Overweight and Obesity: Results of the I.Family Study

Increasing data suggest that overnutrition-induced obesity may trigger an inflammatory process in adipose tissue and upturn in the innate immune system. Numerous players have been involved in governing the inflammatory response, including epigenetics. Among epigenetic players, miRNAs are emerging as crucial regulators of immune cell development, immune responses, autoimmunity, and inflammation. In this study, we aimed at identifying the involvement of candidate miRNAs in relation to inflammation-associated biomarkers in a subsample of European children with overweight and obesity participating in the I.Family study. The study sample included individuals with increased adiposity since this condition contributes to the early occurrence of chronic low-grade inflammation. We focused on the acute-phase reagent C-reactive protein (CRP) as the primary outcome and selected cytokines as plausible biomarkers of inflammation. We found that chronic low-grade CRP elevation shows a highly significant association with miR-26b-3p and hsa-miR-576-5p in boys. Furthermore, the association of CRP with hsa-miR-10b-5p and hsa-miR-31-5p is highly significant in girls. We also observed major sex-related associations of candidate miRNAs with selected cytokines. Except for IL-6, a significant association of hsa-miR-26b-3p and hsa-miR-576-5p with TNF-α, IL1-Ra, IL-8, and IL-15 levels was found exclusively in boys. The findings of this exploratory study suggest sex differences in the association of circulating miRNAs with inflammatory response biomarkers, and indicate a possible role of miRNAs among the candidate epigenetic mechanisms related to the process of low-grade inflammation in childhood obesity.

MicroRNA-10b promotes arthritis development by disrupting CD4+ T cell subtypes

Rheumatoid arthritis (RA) is an inflammation-involved disorder and features the disruption of CD4⁺ T lymphocytes. Herein, we describe that microRNA-10b-5p (miR-10b) promotes RA progression by disrupting the balance between subsets of CD4⁺ T cells. MiR-10b-deficient mice protected against collagen antibody-induced arthritis (CAIA) model. RNA sequencing results indicated that disordered genes in miR-10b^−/− CAIA model are closely associated with CD4⁺ T cells differentiation. Moreover, miR-10b mimics promoted Th1/Th17 and suppressed Th2/Treg cells differentiation, whereas miR-10b inhibitor induced contrary effects. In addition, GATA3 and PTEN was confirmed as two targets of miR-10b, and GATA3 siRNA could increase Th1 and reduce Th2 cells meanwhile PTEN siRNA could increase Th17 and decrease Treg cells. Furthermore, miR-10b inhibitor significantly ameliorated collagen-induced arthritis (CIA) development by attenuating the dysfunctional CD4⁺ T cell subpopulations. The present findings suggest that miR-10b could disrupt the balance of CD4⁺ T subsets, while suppressed miR-10b could attenuate the severity of experimental arthritis, which provided us a novel mechanistic and therapeutic insight into the RA.

Maternal Exercise Programs Glucose and Lipid Metabolism and Modulates Hepatic miRNAs in Adult Male Offspring

Detrimental exposures in mothers are recognized as risk factors for the development of metabolic dysfunction in offspring. In contrast, maternal exercise has been reported to be an effective strategy to maintain offspring health. However, the mechanisms underlying the protective effects of maternal exercise on adult offspring metabolic homeostasis are largely unclear. This study aims to investigate whether maternal exercise before and during pregnancy could combat the adverse effects of maternal high-fat diet (HFD) on metabolism in 24-week-old male offspring and to explore the role of miRNAs in mediating the effects. Female C57BL/6 mice were fed with either control diet or HFD 3-week prior to breeding and throughout pregnancy and lactation, among whom half of the HFD-fed mice were submitted to voluntary wheel running training 3-week before and during pregnancy. Male offspring were sedentary and fed with a control diet from weaning to 24 weeks. Body weight, the content of inguinal subcutaneous adipose tissue and perirenal visceral adipose tissue, glucose tolerance, and serum insulin and lipids in offspring were analyzed. Hepatic tissues were collected for transcriptome and miRNA sequencing and reverse transcription-quantitative polymerase chain reaction validation. The results showed that maternal HFD resulted in significant glucose intolerance, insulin resistance, and dyslipidemia in adult offspring, which were negated by maternal exercise. Transcriptome sequencing showed that maternal exercise reversed perinatal HFD-regulated genes in adult offspring, which were enriched in glucose and lipid metabolic-related signaling pathways. At the same time, maternal exercise significantly rescued the changes in the expression levels of 3 hepatic miRNAs in adult offspring, and their target genes were involved in the regulation of cholesterol biosynthesis and epigenetic modification, which may play an important role in mediating the intergenerational metabolic regulation of exercise. Overall, our research pioneered the role of miRNAs in mediating the programming effects of maternal exercise on adult offspring metabolism, which might provide novel insight into the prevention and treatment of metabolic disorders in early life.

Serum miR-3620-3p as a Novel Biomarker for Ankylosing Spondylitis

Objective

Using microRNA (miR) as a biomarker has been a new way for diagnosing many diseases Although many studies on miR-biomarker have been published, researches on miR-biomarker in ankylosing spondylitis (AS) are limited Therefore, the objective of this study was to valiate a candidate serum miR as a novel disease-specific novel miR for AS.

Methods

Total RNAs were extracted from sera samples of patients with AS (n=57), patients with rheumatoid arthritis (RA) (n=37), or healthy controls (HC) (n=19) Through serum miR screening by microarray, differential levels of miR were subsequently validated by real time PCR At the time of serum sampling, clinical values such as sex, age, disease duration, AS-disease activity score, uveitis, peripheral arthritis, enthesitis, human leukocyte antigen-B27 presence, and recent medication were evaluated.

Results

We found that the expression level of serum miR-3620-3p in AS was notably lower than that in RA or HC The receiver-operator characteristics curve for determining the diagnostic accuracy showed an area under the curve of 0919 (p<0001) with a sensitivity of 871% and a specificity of 860% Correlation studies showed that the expression level of miR-3620-3p was only associated with the development of uveitis (p<005).

Conclusion

Serum miR-3620-3p can be as a new biomarker for diagnosing AS.

LncRNA MIAT Promotes Allergic Inflammation and Symptoms by Targeting MiR-10b-5p in Allergic Rhinitis Mice

BACKGROUND

Allergic rhinitis (AR) is one of the most common noninfectious respiratory diseases caused by immunoglobulin E (IgE) response.

OBJECTIVE

The study sought to explore the relationship between lncRNA MIAT and miR-10b-5p and their interaction in the regulation of allergic phenotypes in allergic rhinitis (AR) mice.

METHODS

A mice model of AR was constructed using ovalbumin (OVA) sensitization. AR mice were treated with miR-10b-5p agomiR and LNA mediated lncRNA MIAT. The targeting relationship between MIAT and miR-10b-5p was analyzed by the ENCORI website and dual-luciferase reporter assay. The numbers of rubbing and sneezing of mice were counted. Hematoxylin-eosin (HE) staining visualized the eosinophils infiltration in nasal mucosa tissues of mice. The percentage of Th17 cells was quantitated by flow cytometry analysis. ELISA was used to detect the levels of serum OVA-specific IgE, the Th12 cytokine IL-4, and inflammatory cytokines (IL-6, IL-17).

RESULTS

MIAT was up-regulated in the nasal mucosa of AR mice, while miR-10b-5p was down-regulated. MIAT directly suppressed miR-10b-5p expression in AR mice. The numbers of rubbing and sneezing, the percentage of Th17 cells, and the levels of OVA-specific IgE, IL-4, IL-6, and IL-17 in AR mice were decreased by miR-10b-5p overexpression, which was reversed by MIAT overexpression. The eosinophils infiltration in AR mice was inhibited by miR-10b-5p overexpression, which was also reversed by MIAT overexpression.

CONCLUSION

The present study demonstrates that MIAT overexpression Promotes allergic inflammation and symptoms by activating Th17 immune response via miR-10b-5p inhibition.

Novel Insights Into Rheumatoid Arthritis Through Characterization of Concordant Changes in DNA Methylation and Gene Expression in Synovial Biopsies of Patients With Differing Numbers of Swollen Joints

In this study, we sought to characterize synovial tissue obtained from individuals with arthralgia and disease-specific auto-antibodies and patients with established rheumatoid arthritis (RA), by applying an integrative multi-omics approach where we investigated differences at the level of DNA methylation and gene expression in relation to disease pathogenesis. We performed concurrent whole-genome bisulphite sequencing and RNA-Sequencing on synovial tissue obtained from the knee and ankle from 4 auto-antibody positive arthralgia patients and thirteen RA patients. Through multi-omics factor analysis we observed that the latent factor explaining the variance in gene expression and DNA methylation was associated with Swollen Joint Count 66 (SJC66), with patients with SJC66 of 9 or more displaying separation from the rest. Interrogating these observed differences revealed activation of the immune response as well as dysregulation of cell adhesion pathways at the level of both DNA methylation and gene expression. We observed differences for 59 genes in particular at the level of both transcript expression and DNA methylation. Our results highlight the utility of genome-wide multi-omics profiling of synovial samples for improved understanding of changes associated with disease spread in arthralgia and RA patients, and point to novel candidate targets for the treatment of the disease.

miRNAs Alter T Helper 17 Cell Fate in the Pathogenesis of Autoimmune Diseases

T helper 17 (Th17) cells are characterized by the secretion of the IL-17 cytokine and are essential for the immune response against bacterial and fungal infections. Despite the beneficial roles of Th17 cells, unrestrained IL-17 production can contribute to immunopathology and inflammatory autoimmune diseases, including multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease. Although these diverse outcomes are directed by the activation of Th17 cells, the regulation of Th17 cells is incompletely understood. The discovery that microRNAs (miRNAs) are involved in the regulation of Th17 cell differentiation and function has greatly improved our understanding of Th17 cells in immune response and disease. Here, we provide an overview of the biogenesis and function of miRNA and summarize the role of miRNAs in Th17 cell differentiation and function. Finally, we focus on recent advances in miRNA-mediated dysregulation of Th17 cell fate in autoimmune diseases.

Gut microbiota-microRNA interactions in ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic autoimmune inflammatory disability that is part of the rheumatic disease group of spondyloarthropathies. AS commonly influences the joints of the axial skeleton. The contributions to AS pathogenesis of genetic susceptibility (particularly HLA-B27 and ERAP-1) and epigenetic modifications, like non-coding RNAs, as well as environmental factors, have been investigated over the last few years. But the fundamental etiology of AS remains elusive to date. The evidence summarized here indicates that in the immunopathogenesis of AS, microRNAs and the gut microbiome perform critical functions. We discuss significant advances in the immunological mechanisms underlying AS and address potential cross-talk between the gut microbiome and host microRNAs. This critical interaction implicates a co-evolutionary symbiotic link between host immunity and the gut microbiome.

Circulating miRNAs in bone health and disease

microRNAs have evolved as important regulators of multiple biological pathways essential for bone homeostasis, and microRNA research has furthered our understanding of the mechanisms underlying bone health and disease. This knowledge, together with the finding that active or passive release of microRNAs from cells into the extracellular space enables minimal-invasive detection in biofluids (circulating miRNAs), motivated researchers to explore microRNAs as biomarkers in several pathologic conditions, including bone diseases. Thus, exploratory studies in cohorts representing different types of bone diseases have been performed. In this review, we first summarize important molecular basics of microRNA function and release and provide recommendations for best (pre-)analytical practices and documentation standards for circulating microRNA research required for generating high quality data and ensuring reproducibility of results. Secondly, we review how the genesis of bone-derived circulating microRNAs via release from osteoblasts and osteoclasts could contribute to the communication between these cells. Lastly, we summarize evidence from clinical research studies that have investigated the clinical utility of microRNAs as biomarkers in musculoskeletal disorders. While previous reviews have mainly focused on diagnosis of primary osteoporosis, we have also included studies exploring the utility of circulating microRNAs in monitoring anti-osteoporotic treatment and for diagnosis of other types of bone diseases, such as diabetic osteopathy, bone degradation in inflammatory diseases, and monogenetic bone diseases.

Hsa_circ_0056558 regulates cyclin-dependent kinase 6 by sponging microRNA-1290 to suppress the proliferation and differentiation in ankylosing spondylitis

The aims of this study was to investigate the influences of hsa_circ_0056558/miR-1290/CDK6 axis in ankylosing spondylitis (AS). The differentially expressed has_circ_0056558 and miR-1290 in AS tissue were analysed based on RNA-seq data and microarray data, respectively. qRT-PCR was performed for detection of relative expression levels of hsa_circ_0056558, miR-1290, CDK6, osteogenic differentiation markers (Runx2 and Osterix) and other inflammatory factors (TNF-α, IL-1β, and IL-6). Western blotting analysis was conducted to test the protein levels of CDK6, osteogenic differentiation markers (Runx2 and Osterix), and PI3K/AKT/NF-κB pathway-associated proteins. CCK8 assay and flow cytometry were conducted to determine cell proliferation and cell apoptotic ability, respectively. Targeted relationships were predicted by bioinformatic analysis and verified by dual-luciferase reporter assay. The differentiation of fibroblast cells was analysed by alkaline phosphatase (ALP) activity assay. Our findings revealed that the expression levels of both circ_0056558 and CDK6 in AS tissue were significantly higher than that in normal samples. Besides, hsa_circ_0056558 could suppress cell proliferation and differentiation by facilitating CDK6 expression and suppressing miR-1290 expression in AS. Over-expression of miR-1290 negatively regulated CDK6 expression to enhance cell proliferation. The protein levels of p-AKT, p-NF-κB p65, and p-IκBα were promoted by hsa_circ_0056558 or CDK6 over-expression while suppressed by miR-1290 up-regulation. In conclusion, our study demonstrated that hsa_circ_0056558 and CDK6 suppressed cell proliferation and differentiation while enhanced cell apoptosis by competitive binding to miR-1290 in AS, which might be possibly achieved by PI3K/AKT/NF-κB pathway, providing us novel therapeutic strategy for AS.

Exosomal miR-10b-5p mediates cell communication of gastric cancer cells and fibroblasts and facilitates cell proliferation

Tumor microenvironment interacts with gastric cancer (GC) cells and affects tumor development. The communication between GC cells and fibroblasts has not been clearly studied and understood. MiR-10b-5p was found highly expressed in tissue and serum samples of patients with advanced stages (stage III+IV) than that in early stage patients (stage I+II). The expression determination of serum exosomal microRNA was also shown with high expression of miR-10b-5p in GC patients with advanced stages. Dual-luciferase activity assays indicated that miR-10b-5p targeted PTEN in GC cells and KLF11 in fibroblasts. The silence of miR-10b-5p up-regulated the expression of PTEN and repressed PI3K/Akt/mTORC1 signaling in GC cells. Clonogenic assay and MTT assay demonstrated that miR-10b-5p inhibitor could significantly reduce the colony formation and cell viability of GC cells. And the incubation of exosomal miR-10b-5p could increase the proliferation of GC cells. Immunohistochemistry staining revealed that high expression of α-SMA was detected in GC tissues with advanced stages. The overexpression of miR-10b-5p down-regulated KLF11 expression and elevated TGFβR1 expression in fibroblasts. In addition, miR-10b-5p inhibitor blocked the secretion of TGFβ1 in GC cells and the directional migration of fibroblasts. Therefore, up-regulated exosomal miR-10b-5p is involved in the interaction of GC cells and fibroblasts in tumor microenvironment via participating in the regulation of TGFβ signaling pathway.

Epigenetics of ankylosing spondylitis: Recent developments

Ankylosing spondylitis (AS) is a chronic inflammatory autoimmune disease which mainly affects the spine, sacroiliac joint and peripheral joints. To date, the exact causes and pathogenesis of AS still remain unknown. It is considered that the pathogenesis of AS is associated with genetic, infection, environment, immunity and other factors. Among them, the role of genetic factors in the pathogenesis of AS has been studied most deeply. However, over the past few years, the function of environmental predisposition and epigenetic modification in the pathogenesis of AS has received extensive attention. This paper summarizes the recent progress in the epigenetics of AS, including abnormal epigenetic modifications at AS-associated genomic loci, such as DNA methylation, histone modification, microRNA, and so on. In summary, the findings of this review attempt to explain the role of epigenetic modification in the occurrence and development of AS. Nevertheless, there are still unknown and complicated aspects worth exploring to deepen our understanding of the pathogenesis of AS.

Exploring IL-17 in spondyloarthritis for development of novel treatments and biomarkers

Spondyloarthritis (SpA) is an umbrella term describing a family of chronic inflammatory rheumatic diseases. These diseases are characterised by inflammation of the axial skeleton, peripheral joints, and entheseal insertion sites throughout the body which can lead to structural joint damage including formation of axial syndesmophytes and peripheral osteophytes. Genetic evidence, preclinical and clinical studies indicate a clear role of interleukin (IL)- 23 and IL-17 as mediators in SpA pathogenesis. Targeting the IL-23/-17 pathways seems an efficient strategy for treatment of SpA patients, and despite the remaining challenges the pathway holds great promise for further advances and improved therapeutic opportunities. Much research is focusing on serological markers and imaging strategies to correctly diagnose patients in the early stages of SpA. Biomarkers may facilitate personalised medicine tailored to each patient's specific disease to optimise treatment efficacy and to monitor therapeutic response. This narrative review focuses on the IL-17 pathway in SpA-related diseases with emphasis on its role in pathogenesis, current approved IL-17 inhibitors, and the need for biomarkers reflecting core disease pathways for early diagnosis and measurement of disease activity, prognosis, and response to therapy.

Regulation of mRNA stability by RBPs and noncoding RNAs contributing to the pathogenicity of Th17 cells

Th17 cells remain one of the most important subsets of T cells in numerous autoimmune and chronic inflammatory diseases. Posttranscriptional regulation (PTR), especially mRNA stability, has recently emerged as an important mechanism that controls the fate of Th17 cells. This review summarizes the current knowledge on RNA-binding proteins (RBPs), microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) that induce mRNA stability changes and their roles in mediating the differentiation, proliferation, function, and migration of Th17 cells. In addition, we summarize the role of RNA modifications and nonsense-mediated mRNA decay (NMD) in Th17 cells. Ongoing research will help to identify practical applications for the regulation of mRNA stability and provide potential targets to prevent and treat Th17-related autoimmune diseases.

Unique inflammatory signature in haemophilic arthropathy: miRNA changes due to interaction between blood and fibroblast-like synoviocytes

In haemophilia, the recurrence of hemarthrosis leads to irreversible arthropathy termed haemophilic arthropathy (HA). However, HA is a unique form of arthropathy in which resident cells, such as fibroblast‐like synoviocytes (FLS), come into direct contact with blood. Therefore, we hypothesized that FLS in HA could have a unique inflammatory signature as a consequence of their contact with blood. We demonstrated with ELISA and ELISPOT analyses that HA‐FLS expressed a unique profile of cytokine secretion, which differed from that of non‐HA‐FLS, mainly consisting of cytokines involved in innate immunity. We showed that unstable cytokine mRNAs were involved in this process, especially through miRNA complexes as confirmed by DICER silencing. A miRNOME analysis revealed that 30 miRNAs were expressed differently between HA and non‐HA‐FLS, with most miRNAs involved in inflammatory control pathways or described in certain inflammatory diseases, such as rheumatoid arthritis or lupus. Analysis of transcriptomic networks, impacted by these miRNAs, revealed that protein processes and inflammatory pathways were particularly targeted in LPS‐induced FLS, and in particular vascularization and osteoarticular modulation pathways in steady‐state FLS. Our study demonstrates that the presence of blood in contact with FLS may induce durable miRNA changes that likely participate in HA pathophysiology.

The RNA binding protein SRSF1 is a master switch of gene expression and regulation in the immune system

Serine/Arginine splicing factor 1 (SRSF1) is an RNA binding protein abundantly expressed in most tissues. The pleiotropic functions of SRSF1 exert multiple roles in gene expression by regulating major steps in transcription, processing, export through the nuclear pores and translation of nascent RNA transcripts. The aim of this review is to highlight recent findings in the functions of this protein and to describe its role in immune system development, functions and regulation.

TWIST1-MicroRNA-10a-MAP3K7 Axis Ameliorates Synovitis of Osteoarthritis in Fibroblast-like Synoviocytes

Synovitis refers to the inflammation of the synovial membrane and is commonly detected in patients with osteoarthritis (OA). Recent reports have suggested that microRNAs (miRNAs) could be a promising target for diagnosis and prognosis in OA. This study examines the effect of microRNA-10a (miR-10a) in fibroblast-like synoviocyte (FLS)-mediated synovitis obtained from patients with OA. Expression of miR-10a is negatively associated with the severity of synovitis. miR-10a inhibited proliferation, migration, and secretion of pro-inflammatory cytokines of OA-FLS that were obtained from OA patients in vitro. By using a patient-derived xenograft (PDX) model, miR-10a repressed proliferation of OA-FLSs and production of OA synovium-derived pro-inflammatory cytokines in vivo. Twist Family BHLH Transcription Factor 1 (TWIST1) and mitogen-activated protein kinase kinase kinase 7 (MAP3K7) were identified as an upstream regulator and direct target of miR-10a in OA-FLSs, respectively. Nuclear factor κB (NF-κB) signaling pathway, a downstream pathway of MAP3K7, was also repressed by miR-10a in OA-FLSs. To summarize, the TWIST1-miR-10a-MAP3K7-NF-κB pathway mediates the development of synovitis in OA. miR-10a functions as an anti-inflammatory mediator in OA-FLS.

Tackling the autoimmune side in Spondyloarthritis: A systematic review

Spondyloarthritis (SpA) are a heterogeneous group of inflammatory chronic diseases characterized by sharing common pathogenic, clinical and radiologic features. The aim of this review is to support clinicians in understanding and managing this complex disease, from pathogenesis to therapeutic targets, through a systematic review of the current literature in accordance with PRISMA guidelines and checklist. HLA-B27 has been found to be associated with axial involvement either in SA and in PsA patients: it might be involved through presentation of an "arthritogenic peptide" to autoreactive CD8+ T cells or might accumulate in misfolded form and induce production pro-inflammatory cytokines by binding to several innate immune receptors. This genetic background in combination with mechanical stress leads to the activation of both innate and acquired immune responses as well as a possible role of autoimmunity in SpA pathogenesis. The release of IL-23 and IL-17 is relevant for their systemic and local effect on bone, inducing the activation of osteoclasts. Thus, the regulatory role of IL-17 on fibroblasts, osteoblasts and chondrocytes has an impact in both synovial inflammation and joint destruction. Innovative therapies targeting IL-12/23 and IL-17 and the use of small targeted synthetic molecules, as JAK-inhibitors, proved to be effective in SpA patients representing an alternative strategy to TNF-inhibitors.

A cancer stem cell-like phenotype is associated with miR-10b expression in aggressive squamous cell carcinomas

Background

Cutaneous squamous cell carcinomas (cSCC) are the primary cause of premature deaths in patients suffering from the rare skin-fragility disorder recessive dystrophic epidermolysis bullosa (RDEB), which is in marked contrast to the rarely metastasizing nature of these carcinomas in the general population. This remarkable difference is attributed to the frequent development of chronic wounds caused by impaired skin integrity. However, the specific molecular and cellular changes to malignancy, and whether there are common players in different types of aggressive cSCCs, remain relatively undefined.

Methods

MiRNA expression profiling was performed across various cell types isolated from skin and cSCCs. Microarray results were confirmed by qPCR and by an optimized in situ hybridization protocol. Functional impact of overexpression or knock-out of a dysregulated miRNA was assessed in migration and 3D-spheroid assays. Sample-matched transcriptome data was generated to support the identification of disease relevant miRNA targets.

Results

Several miRNAs were identified as dysregulated in cSCCs compared to control skin. These included the metastasis-linked miR-10b, which was significantly upregulated in primary cell cultures and in archival biopsies. At the functional level, overexpression of miR-10b conferred the stem cell-characteristic of 3D-spheroid formation capacity to keratinocytes. Analysis of miR-10b downstream effects identified a novel putative target of miR-10b, the actin- and tubulin cytoskeleton-associated protein DIAPH2.

Conclusion

The discovery that miR-10b mediates an aspect of cancer stemness – that of enhanced tumor cell adhesion, known to facilitate metastatic colonization – provides an important avenue for future development of novel therapies targeting this metastasis-linked miRNA.

MicroRNAs in ankylosing spondylitis: Function, potential and challenges

Epigenetic mechanisms such as DNA methylation, histone modifications and non-coding RNA, are considered the essential connection between a disorder's onset and the environment, on a permissive genetic background. Among autoimmune and inflammatory-mediated disorders, Ankylosing Spondylitis (AS), a chronic arthritis of the spine, is a very good example for the weight of epigenetics' contribution. MicroRNAs (miRNAs) are single-stranded nucleotides which regulate gene expression and are involved in pathological and physiological processes. In this manuscript we provide a clarification on the role of microRNAs in AS, with a focus on the mechanisms of pathogenesis. In specific, we have examined the contribution of miRNAs in the processes of inflammation, new bone formation and T-cell function, and the pathways (i.e. Wnt, BMP, TGFβ signalling etc.) they regulate. The utility of miRNAs in better understanding AS pathogenesis is undisputed and their utility as therapeutic opportunity is strongly increasing.

Could IL-17A Be a Novel Therapeutic Target in Diabetic Nephropathy?

Chronic kidney disease has become a major medical issue in recent years due to its high prevalence worldwide, its association with premature mortality, and its social and economic implications. A number of patients gradually progress to end-stage renal disease (ESRD), requiring then dialysis and kidney transplantation. Currently, approximately 40% of patients with diabetes develop kidney disease, making it the most prevalent cause of ESRD. Thus, more effective therapies for diabetic nephropathy are needed. In preclinical studies of diabetes, anti-inflammatory therapeutic strategies have been used to protect the kidneys. Recent evidence supports that immune cells play an active role in the pathogenesis of diabetic nephropathy. Th17 immune cells and their effector cytokine IL-17A have recently emerged as promising targets in several clinical conditions, including renal diseases. Here, we review current knowledge regarding the involvement of Th17/IL-17A in the genesis of diabetic renal injury, as well as the rationale behind targeting IL-17A as an additional therapy in patients with diabetic nephropathy.

miR-17-5p Regulates Heterotopic Ossification by Targeting ANKH in Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease characterized with heterotopic ossification of the axis joints ligaments, resulting in joint disability. MicroRNAs (miRNAs) are regulators of mRNAs that play a crucial role in the AS pathological process. Here, we showed that the level of miR-17-5p was significantly higher in fibroblasts and ligament tissues from AS patients as compared to the non-AS individuals. Knockdown of the miR-17-5p from the fibroblasts derived from AS patients exhibited decreased osteogenic differentiation and ossification. On the other hand, AS patient-derived fibroblasts overexpressing miR-17-5p displayed the increased osteogenesis. Furthermore, inhibition of miR-17-5p ameliorated osteophyte formation, and the sacroiliitis phenotype in AS rats received emulsified collagen. Mechanistically, miR-17-5p regulated osteogenic differentiation by targeting the 3' UTR of ankylosis protein homolog (ANKH). Also, downregulation of miR-17-5p slowed AS progression through regulation of cytokines, such as dickkopf-1 (DKK1) and vascular endothelial growth factor (VEGF). In conclusion, our findings reveal a role of the miR-17-5p-ANKH axis in the regulation of heterotopic ossification, which is essential for therapeutic intervention in heterotopic ossification in AS.

The circ_0021977/miR-10b-5p/P21 and P53 regulatory axis suppresses proliferation, migration, and invasion in colorectal cancer

An in-depth understanding of circular RNAs (circRNAs) indicates that they are abundant in the eukaryotic transcriptome. Many circRNAs act as microRNA sponges; thus, they represent a new type of regulatory factor. However, the role of circRNA in colorectal cancer (CRC) remains largely unknown. Low circ_0021977 expression in patients with CRC is associated with higher tug-lymph node metastasis (TNM) stage and poorer prognosis compared with patients with high circ_0021977 expression. Moreover, miR-10b-5p was shown to be a target of circ_0021977, and p21 and p53 are suggested to be putative target genes of miR-10b-5p. The results showed that the circ_0021977/miR-10b-5p/p21&p53 regulatory axis suppresses proliferation, migration, and invasion by CRC cells. This evidence reveals new relationships and brings new highlights to the treatment of CRC.

Differential Expression Profiles of the Transcriptome and miRNA Interactome in Synovial Fibroblasts of Rheumatoid Arthritis Revealed by Next Generation Sequencing

Using next-generation sequencing to decipher the molecular mechanisms underlying aberrant rheumatoid arthritis synovial fibroblasts (RASF) activation, we performed transcriptome-wide RNA-seq and small RNA-seq on synovial fibroblasts from rheumatoid arthritis (RA) subject and normal donor. Differential expression of mRNA and miRNA was integrated with interaction analysis, functional annotation, regulatory network mapping and experimentally verified miRNA–target interaction data, further validated with microarray expression profiles. In this study, 3049 upregulated mRNA and 3552 downregulated mRNA, together with 50 upregulated miRNA and 35 downregulated miRNA in RASF were identified. Interaction analysis highlighted contribution of miRNA to altered transcriptome. Functional annotation revealed metabolic deregulation and oncogenic signatures of RASF. Regulatory network mapping identified downregulated FOXO1 as master transcription factor resulting in altered transcriptome of RASF. Differential expression in three miRNA and corresponding targets (hsa-miR-31-5p:WASF3, hsa-miR-132-3p:RB1, hsa-miR-29c-3p:COL1A1) were also validated. The interactions of these three miRNA–target genes were experimentally validated with past literature. Our transcriptomic and miRNA interactomic investigation identified gene signatures associated with RASF and revealed the involvement of transcription factors and miRNA in an altered transcriptome. These findings help facilitate our understanding of RA with the hope of serving as a springboard for further discoveries relating to the disease.

Noncoding RNAs Involved in the Pathogenesis of Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a form of arthritis that can lead to fusion of vertebrae and sacroiliac joints following syndesmophyte formation. The etiology of this painful disease remains poorly defined due to its complex genetic background. There are no commonly accepted methods for early diagnosis of AS, nor are there any effective or efficient clinical treatments. Several noncoding RNAs (ncRNAs) have been linked to AS pathogenesis and inflammation via selective binding of their downstream targets. However, major gaps in knowledge remain to be filled before such findings can be translated into clinical treatments for AS. In this review, we outline recent findings that demonstrate essential roles of ncRNAs in AS mediated via multiple signaling pathways such as the Wnt, transforming growth factor-β/bone morphogenetic protein, inflammatory, T-cell prosurvival, and nuclear factor-κB pathways. The summary of these findings provides insight into the molecular mechanisms by which ncRNAs can be targeted for AS diagnosis and the development of therapeutic drugs against a variety of autoimmune diseases.

Prostaglandin receptor EP4 expression by Th17 cells is associated with high disease activity in ankylosing spondylitis

BACKGROUND

Th17 cells are involved in the pathogenesis of ankylosing spondylitis (AS). However, the mechanism underlying enhanced Th17 cell accumulation in AS remains unknown. The prostaglandin E₂ receptor EP2/EP4 signaling pathway plays a critical role in the development of autoimmune Th17 cells. Interestingly, recent genome-wide association studies (GWAS) have identified five risk alleles for AS in PTGER4, the gene encoding for EP4. The aim of this study was to reveal a possible link between EP4 and disease activity in patients with AS.

METHODS

Th17 cells from patients with AS were analyzed for the transcriptional expression of prostaglandin receptor genes by quantitative RT-PCR. Th17 cells from patients with rheumatoid arthritis (RA) and from healthy individuals served as controls. EP4 receptor expression in Th17 cells was assessed ex vivo by flow cytometry and by western blot. Functional analysis using EP4-specific agonists was performed to reveal how EP4 regulates Th17 cells.

RESULTS

EP4 is significantly overexpressed in Th17 cells from patients with AS compared to Th17 cells from healthy individuals or patients with RA or psoriatic arthritis (PsA). EP4 upregulation is unique to Th17 cells and is not found in other CD4⁺ T cell subsets. Specific activation of EP4 drives Th17 cell development and promotes EP4 expression in a positive feedback loop in AS but not in RA or PsA. Mechanistically, EP4 acts via upregulation of the interleukin-23 receptor (IL-23R), by suppressing the RORγt inhibitor FoxO1 and by enhancing STAT3 phosphorylation. Increased EP4 expression levels in Th17 cells from AS patients correlate with high disease activity as defined by a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score ≥ 4 (r = 0.7591, p = 0.0016).

CONCLUSIONS

EP4 is a potential marker of disease activity in patients with AS. Aberrant EP4 expression might contribute to pathogenic Th17 cell accumulation and represent a new target for the treatment of AS.

Exploring the tissue tropism of pseudorabies virus based on miRNA level analysis

Background

Pseudorabies virus (PRV, or suid herpesvirus, SuHV-1), a member of the herpesvirus family, has an extremely broad host range and threatens the pig industry in China. PRV can evade host innate immunity and infect the kidney, lung, brain and other tissues. At the same time, many studies have reported that microRNA (miRNA) can affect the replication of viruses by regulating gene expression levels.

Results

Here, to identify changes in miRNA expression and post-transcriptional regulation associated with PRV infection in the lung, spleen, and olfactory bulb, we sequenced small RNAs in tissues of rats infected or uninfected with PRV strain XJ (PRV-XJ). Sixty-one, 199 and 29 differentially-expressed miRNAs were identified in the lung, spleen, and olfactory bulb, respectively, of infected compared with uninfected rats. Among the miRNAs differentially-expressed in PRV-infected rats, 36, 171, and 15 miRNAs showed tissue-selective expression in the olfactory bulb, lung and spleen, respectively. All differentially-expressed miRNAs were analyzed for their GO functional annotations and KEGG pathway associations .

Conclusions

In PRV-XJ-infected rats, miRNAs were differentially expressed in the lung, spleen and olfactory bulb. These miRNAs were involved in regulating various pathways of the nervous, respiratory and immune systems, and may affect the tissue tropism of the virus and play pivotal roles in viral infection and proliferation.

miR‑10b‑3p, miR‑8112 and let‑7j as potential biomarkers for autoimmune inner ear diseases

Circulating microRNAs (miRNAs) have been suggested as non‑invasive biomarkers for the diagnosis of several autoimmune diseases. However, to the best of our knowledge, no studies have yet examined the miRNA expression profiles in autoimmune inner ear disease (AIED). The present study aimed to use an miRNA sequencing assay to detect the miRNA expression profiles of serum samples from 3 control mice and 3 antigen‑induced AIED model mice. Differentially expressed miRNAs (DE‑miRNAs) were screened using a t‑test. miRNA target prediction was performed using TargetScan Mouse. Then, the miRNA‑target gene interaction network was constructed and visualized using Cytoscape software. The underlying functions of the target genes of the DE‑miRNAs were predicted using the clusterProfiler package. As a result, 22 miRNAs were identified as DE‑miRNAs between AIED and control mice, including 10 upregulated and 12 downregulated genes. Based on the TargetScan Mouse prediction, 1,958 genes were identified as the targets for the 22 DE‑miRNAs. Functional analysis indicated that only the target genes of 8 miRNAs were respectively enriched for Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways, among which miR‑10b‑3p, let‑7j and miR‑8112 were shared between the two pathway analyses. These 3 miRNAs may be involved in AIED by affecting inflammatory chemokine (miR‑10b‑3p‑C‑C motif chemokine 12), Wnt signaling (miR‑8112‑Wnt9b/Wnt 3a/Wnt2b) and Mucin type O‑glycan biosynthesis pathways (let‑7j‑Galnt2/Galnt12). In conclusion, miR‑10b‑3p, miR‑8112 and let‑7j may be underlying biomarkers for diagnosing AIED.

microRNA-96 promotes osteoblast differentiation and bone formation in ankylosing spondylitis mice through activating the Wnt signaling pathway by binding to SOST

Ankylosing spondylitis (AS) refers to a type of arthritis manifested with chronic inflammation of spine joints. microRNAs (MiRNAs) have been identified as new therapeutic targets for inflammatory diseases. In this study, we evaluated the influence of microRNA-96 (miR-96) on osteoblast differentiation together with bone formation in a murine model of AS. The speculated relationship that miR-96 could bind to sclerostin (SOST) was verified by dual luciferase reporter assay. After successful model establishment, the mice with AS and osteoblasts isolated from mice with AS were treated with mimics or inhibitors of miR-96, or DKK-1 (a Wnt signaling inhibitor). The effects of gain- or loss-of-function of miR-96 on the inflammatory cytokine release (IL-6, IL-10, and TNF-α), alkaline phosphatase (ALP) activity, calcium nodule formation, along with the viability of osteoblasts were determined. It was observed that miR-96 might target and regulate SOST. Besides, miR-96 was expressed at a high level in AS mice while SOST expressed at a low level. TOP/FOP-Flash luciferase reporter assay confirmed that miR-96 activated the Wnt signaling pathway. Moreover, AS mice overexpressing miR-96 exhibited increased contents of IL-6, IL-10 and TNF-α, ALP activity, calcium nodule numbers, and viability of osteoblasts. In contrast, inhibition of miR-96 resulted in suppression of the osteoblast differentiation and bone formation. In conclusion, the study implicates that overexpressing miR-96 could improve osteoblast differentiation and bone formation in AS mice via Wnt signaling pathway activation, highlighting a potential new target for AS treatment.

Biomarkers for Diagnosis of Axial Spondyloarthritis, Disease Activity, Prognosis, and Prediction of Response to Therapy

There exists a major unmet need for biomarkers that can identify axial spondyloarthritis (axSpA) early after disease onset because of the availability of highly effective therapies. Several recent reports have examined the autoantibody response in patients with axSpA through the use of protein microarrays and protein-protein interactions although diagnostic performance of biomarkers identified to date has been inadequate. An example of such a biomarker is protein phosphatase magnesium-dependent 1A. Antibodies to the human leukocyte antigen class II-associated invariant chain peptide (anti-CD74) are candidate diagnostic biomarkers but sensitivity declines with increasing duration of disease. Metabolomic studies have employed nuclear magnetic resonance (NMR) spectrometry to identify disease-specific metabolites related to fat metabolism and intestinal microbial metabolism. A second major unmet need exists for biomarkers of disease activity that have superiority over standard C-reactive protein assessment and reflect MRI inflammation in the axial spine. Several biomarkers reflecting inflammation (calprotectin), angiogenesis (vasoactive endothelial growth factor), and connective tissue turnover (C2M, C3M, and citrullinated metalloproteinase degraded fragment of vimentin) have recently been shown to reflect disease activity when compared with clinical outcomes but comparisons with MRI inflammation are very limited. With increasing availability of highly effective but costly therapies, a third unmet need is biomarkers that can predict response to therapies with different mechanisms of action and are superior to C-reactive protein. Calprotectin is currently the only candidate. Although there are as yet no proven therapies for preventing progression of disease there is an unmet need for biomarkers of prognosis that are more responsive than radiography. Aside from CRP no consistent candidates have emerged. Future studies will need to be prospective, include consecutive patients presenting with undiagnosed back pain, and use more reliable and objective endpoints such as MRI inflammation. Moreover, it has become evident that targeted biomarker studies have not been successful in identifying clinically useful biomarkers and technologies that can simultaneously assess “multiomic” markers will need to be analyzed for future advances. These include more sophisticated metabolomic profiling and universal metabolome-standard (UMS) methodology, next generation RNA sequencing, and affinity-based quantitative proteomics based on the use of nucleic acid binders such as the aptamer-based SOMAscan assay.

Micro-RNAs in inflammatory arthritis: From physiopathology to diagnosis, prognosis and therapeutic opportunities

Micro-RNAs are an area of research exponentially expanding over the past years. These small sequences of 20-22 nucleotides have a strong role as post-transcriptional regulators of gene expression. Inflammatory arthritis pathophysiology involves various key players from innate to adaptive immunity, as well as various signalling pathways of inflammation. In this review, we discuss how micro-RNAs are involved in rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis and juvenile inflammatory arthritis, from pre-clinical phases to established diseases. We describe mi-RNAs key roles in fibroblast like synoviocytes migration, proliferation, apoptosis and cytokine production, in macrophages polarization, as well as in B cells and T cell proliferation and differentiation, with a special emphasis on Treg/Th17 imbalance. We finally discuss the application of these findings in pre-clinical models and highlight opportunities and limits of a therapeutic approach using mi-RNAs agonists or antagonists.

Serum miR-214 as a novel biomarker for ankylosing spondylitis

OBJECTIVE

Serum microRNA (miR) in ankylosing spondylitis (AS) patients has been rarely identified. The objective of this study was to find AS-specific miR in sera of patients with AS.

METHODS

Total RNAs were isolated from whole sera of patients with AS, patients with rheumatoid arthritis (RA), and healthy controls (HC) using miRNeasy Serum/Plasma Kit. The presence of miR was assayed using Agilent 2100 Bioanalyzer Small RNA assay. Each RNA sample was used for miR microarray. To verify microarray results, candidate circulating miRs were validated by quantitative polymerase chain reaction (qPCR) using samples from patients with AS (n = 65), patients with RA (n = 25), and HCs (n = 39). Cycle threshold values were converted to copy numbers by drawing a standard curve using a synthetic chemical standard. All clinical values were also evaluated at the time of miR isolation.

RESULTS

A total of 887 miRs were screened for three groups. Lower expression of miR-214 in AS than in HC and RA was observed after normalization of raw data. Finally, lower expression of serum miR-214 was confirmed in AS after validation by qPCR. Correlation analysis showed that the level of miR-214 of AS was significantly associated with Ankylosing Spondylitis Disease Activity Score-C-reactive protein (r = 0.299, P = 0.02). However, other disease-specific variables showed no statistical significance: gender (P = 0.286), peripheral arthritis (P = 0.634), enthesitis (P = 0.464), dacylitis (P = 0.750), psoriasis (P = 0.552), inflammatory bowel disease (P = 0.369), human leukocyte antigen-B27 positivity (P = 0.473), use of non-steroidal anti-inflammatory drugs (P = 0.448), and use of tumor necrosis factor-blocker in the last 3 months (P = 0.505).

CONCLUSION

miR-214 may serve as a noninvasive biomarker for diagnosis of AS. In addition, expression level of miR-214 was associated with disease activity.

Aberrant expression of interleukin-23-regulated miRNAs in T cells from patients with ankylosing spondylitis

Background

Interleukin (IL)-23 can facilitate the differentiation of IL-17-producing helper T cells (Th17). The IL-23/IL-17 axis is known to play a key role in the immunopathogenesis of ankylosing spondylitis (AS). We hypothesized that the expression of microRNAs (miRNAs, miRs) would be regulated by IL-23 and that these miRNAs could participate in the immunopathogenesis of AS.

Methods

Expression profiles of human miRNAs in K562 cells, cultured in the presence or absence of IL-23 for 3 days, were analyzed by microarray. Potentially aberrantly expressed miRNAs were validated using T-cell samples from 24 patients with AS and 16 control subjects. Next-generation sequencing (NGS) was conducted to search for gene expression and biological functions regulated by specific miRNAs in the IL-23-mediated signaling pathway.

Results

Initial analysis revealed that the expression levels of 12 miRNAs were significantly higher, whereas those of 4 miRNAs were significantly lower, in K562 cells after coculture with IL-23 for 3 days. Among these IL-23-regulated miRNAs, the expression levels of miR-29b-1-5p, miR-4449, miR-211-3p, miR-1914-3p, and miR-7114-5p were found to be higher in AS T cells. The transfection of miR-29b-1-5p mimic suppressed IL-23-mediated signal transducer and activator of transcription 3 (STAT3) phosphorylation in K562 cells. After NGS analysis and validation, we found that miR-29b-1-5p upregulated the expression of angiogenin, which was also upregulated in K562 cells after coculture with IL-23. Increased expression of miR-29b-1-5p or miR-211-3p could enhance interferon-γ expression.

Conclusions

Among the miRNAs regulated by IL-23, expression levels of five miRNAs were increased in T cells from patients with AS. The transfection of miR-29b-1-5p mimic could inhibit the IL-23-mediated STAT3 phosphorylation and might play a role in negative feedback control in the immunopathogenesis of AS.

Expression and Metabolomic Profiling in Axial Spondyloarthritis

PURPOSE OF REVIEW

The purpose of this review is to highlight recent evidence with respect to expression and metabolomic profiling in axial spondyloarthritis (axSpA) that included ankylosing spondylitis (AS).

RECENT FINDINGS

AxSpA is not only characterized by the strongest genetic contribution for any complex rheumatic disease but is also influenced by environmental and immunological factors. Large-scale association-based studies have identified over 100 genetic variants contributing to 30% of the genetic risk of ankylosing spondylitis. Recent studies in global expression and metabolomic profiling appear to highlight common themes despite differences in tissues, populations, techniques, and relative paucity of patients in many of these studies. Expression studies support a role for immunomodulation and bone remodeling in the pathogenesis and progression of axSpA/AS, while metabolomic studies implicate the importance of the intestinal microbial metabolism as well as fat and choline metabolic pathways in AS.

Whodunit? The Contribution of Interleukin (IL)-17/IL-22-Producing γδ T Cells, αβ T Cells, and Innate Lymphoid Cells to the Pathogenesis of Spondyloarthritis

γδ T cells, αβ T cells, and innate lymphoid cells (ILCs) are capable of producing interleukin (IL)-17A, IL-17F, and IL-22. Among these three families of lymphocytes, it is emerging that γδ T cells are, at least in rodents, the main source of these key pro-inflammatory cytokines. γδ T cells were implicated in multiple inflammatory and autoimmune diseases, including psoriasis, experimental autoimmune encephalomyelitis and uveitis, colitis, and rheumatoid arthritis. Recent findings pointed toward a central role of γδ T cells in the pathogenesis of spondyloarthritis (SpA), a group of inflammatory rheumatic diseases affecting the axial skeleton. SpA primarily manifests as inflammation and new bone formation at the entheses, which are connecting tendons or ligaments with bone. In SpA patients, joint inflammation is frequently accompanied by extra-articular manifestations, such as inflammatory bowel disease or psoriasis. In humans, genome-wide association studies could link the IL-23/IL-17 cytokine axis to SpA. Accordingly, antibodies targeting IL-23/IL-17 for SpA treatment already showed promising results in clinical studies. However, the contribution of IL-17-producing γδ T cells to SpA pathogenesis is certainly not an open-and-shut case. Indeed, the cell types that are chiefly involved in local inflammation in human SpA still remain largely unclear. Some studies focusing on blood or synovium from SpA patients reported augmented IL-17-producing and IL-23 receptor-expressing γδ T cells, but other cell types might contribute as well. Here, we summarize the current understanding of how γδ T cells, αβ T cells, and ILCs contribute to the pathogenesis of human and experimental SpA.

Control of T cell effector functions by miRNAs

The differentiation of effector T cells is a tightly regulated process that relies on the selective expression of lineage-defining master regulators that orchestrate unique transcriptional programs, including the production of distinct sets of effector cytokines. miRNAs are post-transcriptional regulators that are now viewed as critical players in these gene expression networks and help defining cell identity and function. This review summarises the role of individual miRNAs in the regulation of the differentiation of effector T cell subsets, including CD4⁺ T helper cells, cytotoxic CD8⁺ T cells and innate-like NKT cells. Moreover, we refer to miRNAs that have been identified to affect simultaneously two or more effector T cell populations, impacting on the balance between effector T cells in vivo, thus constituting potential biomarkers or targets for therapies aiming at boosting immunity or controlling autoimmunity.