Role of histone deacetylase 3 in ankylosing spondylitis via negative feedback loop with microRNA-130a and enhancement of tumor necrosis factor-1α expression in peripheral blood mononuclear cells

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.

Advanced Progress of Histone Deacetylases in Rheumatic Diseases

Rheumatic disease is a disease which is not yet fully clarified to etiology and also involved in a local pathological injury or systemic disease. With the continuous improvement of clinical medical research in recent years, the development process of rheumatic diseases has been gradually elucidated; with the intensely study of epigenetics, it is realized that environmental changes can affect genetics, among which histone acetylation is one of the essential mechanisms in epigenetics. Histone deacetylases (HDACs) play an important role in regulating gene expression in various biological processes, including differentiation, development, stress response, and injury. HDACs are involved in a variety of physiological processes and are promising drug targets in various pathological conditions, such as cancer, cardiac and neurodegenerative diseases, inflammation, metabolic and immune disorders, and viral and parasitic infections. In this paper, we reviewed the roles of HDACs in rheumatic diseases in terms of their classification and function.

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.

Therapeutic effects of combining curcumin and swimming in osteoarthritis using a rat model

Osteoarthritis (OA) is a common debilitating degenerative disease of the elderly. We aimed to study the therapeutic effects of combining curcumin and swimming in monosodium iodoacetate (MIA)-induced OA in a rat model. The rats were divided into 5 groups (n = 9). Group 1 received saline and served as a control group. Groups 2-5 were injected intra-articularly in the right knee with 100 μL MIA. One week later, groups 3 and 5 were started on daily swimming sessions that gradually increased to 20-mins per session, and for groups 4 and 5, oral curcumin was administered at a dose of 200 mg/kg for 4 weeks. The combination therapy (curcumin + swimming) showed the most effective results in alleviating pain and joint stiffness as well as improving histological and radiological osteoarthritis manifestations in the knee joints. The combination modality also reduced serum C-reactive protein and tissue cartilage oligomeric matrix protein levels. Mechanistically, rats received dual treatment exhibited restoration of miR-130a and HDAC3 expression. The dual treatment also upregulated PPAR-γ alongside downregulation of NF-κB and its inflammatory cytokine targets TNF-α and IL-1β. Additionally, there was downregulation of MMP1 and MMP13 in the treated rats. In conclusion, our data showed that there is a therapeutic potential for combining curcumin with swimming in OA, which is attributed, at least in part, to the modulation of miR-130a/HDAC3/PPAR-γ signaling axis.

Screening and identification of key chromatin regulator biomarkers for ankylosing spondylitis and drug prediction: evidence from bioinformatics analysis

BACKGROUND

Ankylosing spondylitis (AS) is one of the most common immune-mediated arthritic diseases worldwide. Despite considerable efforts to elucidate its pathogenesis, the molecular mechanisms underlying AS are still not fully understood.

METHODS

To identify candidate genes involved in AS progression, the researchers downloaded the microarray dataset GSE25101 from the Gene Expression Omnibus (GEO) database. They identified differentially expressed genes (DEGs) and functionally enriched them for analysis. They also constructed a protein-protein interaction network (PPI) using STRING and performed cytoHubba modular analysis, immune cell and immune function analysis, functional analysis and drug prediction.The results showed that DEGs were mainly associated with histone modifications, chromatin organisation, transcriptional coregulator activity, transcriptional co-activator activity, histone acetyltransferase complexes and protein acetyltransferase complexes.

RESULTS

The researchers analysed the differences in expression between the CONTROL and TREAT groups in terms of immunity to determine their effect on TNF-α secretion. By obtaining hub genes, they predicted two therapeutic agents, AY 11-7082 and myricetin.

CONCLUSION

The DEGs, hub genes and predicted drugs identified in this study contribute to our understanding of the molecular mechanisms underlying the onset and progression of AS. They also provide candidate targets for the diagnosis and treatment of AS.

Antibodies of the immunoglobulin a isotype to novel antigens in early axial spondyloarthritis

Introduction

There is an unmet need for biomarkers to identify patients with axial spondyloarthritis (axSpA). Increasing evidence suggest the presence of autoantibodies in a subset of axSpA patients. The aim of this study was to identify novel IgA antibodies in early axSpA patients and to determine their diagnostic potential in combination with previously determined IgG antibodies against UH (Hasselt University)-axSpA-IgG antigens.

Methods

An axSpA cDNA phage display library constructed from axSpA hip synovium, was used to screen for novel IgA antibodies in plasma from early axSpA patients. The presence of these antibodies against novel UH-axSpA-IgA antigens was determined in two independent axSpA cohorts, in healthy controls and in patients with chronic low back pain.

Results

We identified antibodies to 7 novel UH-axSpA-IgA antigens, of which 6 correspond to non-physiological peptides and 1 to the human histone deacetylase 3 (HDAC3) protein. IgA antibodies against 2 of these 7 novel UH-axSpA-IgA antigens and IgG antibodies against 2 of the previously identified antigens were significantly more present in early axSpA patients from the UH cohort (18/70, 25.7%) and the (Bio)SPAR cohort (26/164, 15.9%), compared to controls with chronic low back pain (2/66, 3%). Antibodies to this panel of 4 antigens were present in 21.1% (30/142) of patients with early axSpA from the UH and (Bio)SPAR cohorts. The positive likelihood ratio for confirming early axSpA using antibodies to these 4 UH-axSpA antigens was 7.0. So far, no clinical correlation between the novel identified IgA antibodies and inflammatory bowel disease could be identified.

Discussion

In conclusion, screening an axSpA cDNA phage display library for IgA reactivity resulted in the identification of 7 novel UH-axSpA-IgA antigens, of which 2 show promising biomarker potential for the diagnosis of a subset of axSpA patients, in combination with previously identified UH-axSpA-IgG antigens.

Monocytes and Macrophages in Spondyloarthritis: Functional Roles and Effects of Current Therapies

Spondyloarthritis (SpA) is a family of chronic inflammatory diseases, being the most prevalent ankylosing spondylitis (AS) and psoriatic arthritis (PsA). These diseases share genetic, clinical and immunological features, such as the implication of human leukocyte antigen (HLA) class I molecule 27 (HLA-B27), the inflammation of peripheral, spine and sacroiliac joints and the presence of extra-articular manifestations (psoriasis, anterior uveitis, enthesitis and inflammatory bowel disease). Monocytes and macrophages are essential cells of the innate immune system and are the first line of defence against external agents. In rheumatic diseases including SpA, the frequency and phenotypic and functional characteristics of both cell types are deregulated and are involved in the pathogenesis of these diseases. In fact, monocytes and macrophages play key roles in the inflammatory processes characteristics of SpA. The aim of this review is analysing the characteristics and functional roles of monocytes and macrophages in these diseases, as well as the impact of different current therapies on these cell types.

Exploring the Extracellular Vesicle MicroRNA Expression Repertoire in Patients with Rheumatoid Arthritis and Ankylosing Spondylitis Treated with TNF Inhibitors

Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) belong to the most common inflammatory rheumatic diseases. MicroRNAs (miRNAs) are small 18–22 RNA molecules that function as posttranscriptional regulators. They are abundantly present within extracellular vesicles (EVs), small intercellular communication vesicles that can be found in bodily fluids and that have key functions in pathological and physiological pathways. Recently, EVs have gained much interest because of their diagnostic and therapeutic potential. Using NanoString profiling technology, the miRNA repertoire of serum EVs was determined and compared in RA and AS patients before and after anti-TNF therapy to assess its potential use as a diagnostic and prognostic biomarker. Furthermore, possible functional effects of those miRNAs that were characterized by the most significant expression changes were evaluated using in silico prediction algorithms. The analysis revealed a unique profile of differentially expressed miRNAs in RA and AS patient serum EVs. We identified 12 miRNAs whose expression profiles enabled differentiation between RA and AS patients before induction of anti-TNF treatment, as well as 4 and 14 miRNAs whose repertoires were significantly changed during the treatment in RA and AS patients, respectively. In conclusion, our findings suggest that extracellular vesicle miRNAs could be used as potential biomarkers associated with RA and AS response to biological treatment.

MicroRNAs as Biomarkers for the Diagnosis of Ankylosing Spondylitis: A Systematic Review and Meta-Analysis

Background: Abnormal expression levels of microRNAs (miRNAs) were observed in ankylosing spondylitis (AS) in recent articles, suggesting that miRNAs may be used as biomarkers for AS diagnoses. In this paper, we conducted a meta-analysis to identify the overall diagnostic accuracy of miRNA biomarkers in AS patients.

Methods: An extensive search was undertaken in PubMed, Embase, Cochrane databases, and Wan Fang database up to 30 December 2020 using the following key words: (“microRNAs” or “microRNA” or “miRNA” or “miR” or “RNA, Micro” or “Primary MicroRNA”) and (“Spondylitis Ankylosing” or “Spondyloarthritis Ankylopoietica” or “Ankylosing Spondylarthritis” or “Ankylosing Spondylarthritides” or “Spondylarthritides Ankylosing” or “Ankylosing Spondylitis”) and (“blood” or “serum” or “plasma”). Statistical evaluation of dysregulated miRNAs using the sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and the area under the curve (AUC).

Results: Twenty-nine articles reporting on the miRNAs of AS were included. A total of 42 miRNAs were observed to be up-regulated and 45 miRNAs were down-regulated in the AS cases compared with the controls. Besides, 29 studies from nine articles were included in our meta-analysis. The pooled sensitivity, specificity, PLR, NLR, DOR, and AUC were 0. 76 (95% CI, 0.70–0.81), 0.80 (95% CI, 0.74–0.85), 3.75 (95% CI, 2.82–5.01), 0.30 (95% CI, 0.24–0.39), 12.32 (95% CI, 7.65–19.83), 0.85 (95% CI, 0.81–0.88), respectively, suggesting a good diagnostic accuracy of miRNAs for AS.

Conclusions: Circulating miRNAs are deregulated in AS patients. miRNAs may be used as a relatively non-invasive biomarkers for the detection of AS.

Genetics, Epigenetics, and Gender Impact in Axial-Spondyloarthritis Susceptibility: An Update on Genetic Polymorphisms and Their Sex Related Associations

Spondyloarthritis (SpA) is a group of chronic inflammatory rheumatic disease that can be divided into predominantly axial or predominantly peripheral involvement, with or without associated psoriasis, inflammatory bowel disease or previous infection. Axial SpA (axSpA) encompasses ankylosing spondylitis (AS) with radiological sacroiliitis, and a type without radiographic sacroiliitis, called “non-radiographic axial SpA” (nr-axSpA). Males and females show large differences in their susceptibility to SpA, such as distinctions in clinical patterns, phenotypes and in therapeutical response, particularly to TNF inhibitors (TNFi). Several studies indicate that AS women have doubled risk to failure TNFi compared with males. This diversity in drugs’ efficacy among women and men may be caused by differences in the balance of sex hormones and in gene-specific expression likely triggered by X-chromosome instability and gene-specific epigenetic modifications. Evidence reported that polymorphisms in microRNAs on X- and other chromosomes, such as miR-146a, miR-155, miR-125a-5p, miR-151a-3p and miR-22-3p, miR-199a-5p could be involved in the different clinical presentation of SpA, as well as disease activity. In addition, association with non−response to TNFi treatment and presence of IRAK3 and CHUCK genes in SpA patients was recently detected. Finally, polymorphisms in genes involved in IL-23/IL-17 pathway, such as in drug pharmacodynamics and pharmacokinetics may have a role in response to TNFi, IL17i, and IL23i. A major understanding of genomic variability could help in the development of new therapeutic targets or in taking advantages of different mechanisms of action of biological drugs. Moving from the multifactorial etiology of disease, the present review aims at evaluating genetic and epigenetic factors and their relationship with sex and bDMARDs response, helping to investigate the different expression among males and females of genes on X- and other chromosomes, as well as mi-RNA, to highlight relationships between sex and occurrence of specific phenotypes and symptoms of the disease. Moreover, the role of the epigenetic modification in relation to immune-regulatory mechanisms will be evaluated.

MicroRNAs in Axial Spondylarthritis: an Overview of the Recent Progresses in the Field with a Focus on Ankylosing Spondylitis and Psoriatic Arthritis

Purpose of Review

To highlight the recent discoveries and lines of evidence on the role of microRNAs in ankylosing spondylitis (AS) and psoriatic arthritis (PsA), focusing on their expression profiling and mechanisms of action.

Recent Findings

AS and PsA are chronic inflammatory musculoskeletal diseases with axial manifestations and represent an excellent model for studying microRNAs contribution to the disease pathogenesis, particularly through immunomodulation, inflammation, and bone remodelling, or their value as candidate diagnostic and prognostic biomarkers.

Summary

MicroRNAs are single-stranded nucleotides able to regulate gene expression. They are a key component of the epigenetic machinery, involved in physiological and pathological processes. The contribution of microRNAs in AS and PsA (such as miR-29a in regulating bone metabolism) is highlighted by several works in the field but their utility as possible markers must be still confirmed, particularly in larger patients’ cohorts.

HDAC3 increases HMGB3 expression to facilitate the immune escape of breast cancer cells via down-regulating microRNA-130a-3p

OBJECTIVE

Histone deacetylase 3 (HDAC3) has been reported to repress the expression of various genes by eliminating acetyl group from histone. The objective of this study was to discuss the effect of HDAC3/microRNA-130a-3p (miR-130a-3p)/high-mobility group box 3 (HMGB3) on immune escape of breast cancer.

METHODS

HDAC3, miR-130a-3p and HMGB3 expression in breast cancer tissues and cells were tested, and the correlation between HDAC3, miR-130a-3p and HMGB3 was analyzed. CD8, CD69 and programmed cell death protein 1 (PD-1) expression was detected. MDA-MB-231 cells were treated with relative plasmid of HDAC3 or miR-130a-3p to test cell viability, migration, epithelial-mesenchymal transition (EMT) and apoptosis in MDA-MB-231 cells. The cytotoxicity of CD8+/CD69+/PD-1+T cells in MDA-MB-231 cells was tested, and CD8+/CD69+/PD-1+T cell proliferation and apoptosis before and after co-culture with MDA-MB-231 cells were detected.

RESULTS

HDAC3 and HMGB3 expression were raised and miR-130a-3p expression was diminished in breast cancer tissues and cells. HDAC3 was negatively correlated with miR-130a-3p while miR-130a-3p was negatively correlated with HMGB3. Down-regulating HDAC3 or up-regulating miR-130a-3p restrained cell viability, migration, EMT and anti-CD8+/CD69+/PD-1+T cytotoxicity and facilitated apoptosis of breast cancer cells. HDAC3 regulated HMGB3 by mediating miR-130a-3p expression. Down-regulating miR-130a-3p reversed the role of HDAC3 reduction on breast cancer cells. HDAC3 regulated CD8+/CD69+/PD-1+T cell proliferation and apoptosis by mediating miR-130a-3p.

CONCLUSION

This study provides evidence that HDAC3 increases HMGB3 expression to promote the immune escape of breast cancer cells via down-regulating miR-130a-3p.

Inhibited HDAC3 or Elevated MicroRNA-494-3p Plays a Protective Role in Myocardial Ischemia-Reperfusion Injury via Suppression of BRD4

Increased histone deacetylase 3 (HDAC3) has been demonstrated to contribute to the pathogenesis of myocardial ischemia-reperfusion injury (MI/RI). Therefore, the goal of this study was to investigate how HDAC3 regulated MI/RI by mediating microRNA (miR)-494-3p/dromodomain-containing protein 4 (BRD4) axis. The MI/RI model was established by ligating the right anterior descending coronary artery. Cardiomyocytes from newborn mice were treated with hypoxia/reoxygenation (H/R). Gain-of-function and loss-of-function approaches were implemented to figure out the roles of miR-494-3p and HDAC3 in MI/RI. miR-494-3p, HDAC3, and BRD4 in myocardial tissues of mice with MI/RI and H/R-treated cardiomyocytes were detected. The relationships between miR-494-3p and HDAC3 and BRD4 were identified. Reduced miR-494-3p and upregulated HDAC3 and BRD4 exhibited in myocardial tissues of mice with MI/RI and H/R-treated cardiomyocytes. Inhibited HDAC3 or elevated miR-494-3p repressed the inflammation and apoptosis, improved cardiac function, and ameliorated myocardial injury in myocardial tissues of mice with MI/RI. Suppression of HDAC3 or elevation of miR-494-3p depressed inflammation and apoptosis and promoted cell viability of primary cardiomyocytes. miR-494-3p targeted BRD4. The study concludes that suppressed HDAC3 plays a protective role in MI/RI by upregulation of miR-494-3p and inhibition of BRD4, which could be helpful for MI/RI therapy.

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.

Serum miRNA Signature in Rheumatoid Arthritis and "At-Risk Individuals"

Background

MicroRNAs (miRNAs) are small non-coding RNAs which have been implicated as potential biomarkers or therapeutic targets in autoimmune diseases. This study examines circulatory miRNAs in RA patients and further investigates if a serum miRNA signature precedes clinical manifestations of disease in arthralgia or “at-risk individuals”.

Methods

Serum was collected from HC subjects (N = 20), RA patients (N = 50), and arthralgia subjects (N = 10), in addition to a subgroup of the RA patients post-methotrexate (MTX) (N = 18). The FirePlex miRNA Immunology-V2 panel was selected for multiplex analysis of 68 miRNAs in each sample. DNA intelligent analysis (DIANA)-mirPath and Ingenuity Pathway Analysis (IPA) software were used to predict pathways targeted by the dysregulated miRNAs.

Results

8 miRNA (miR-126-3p, let-7d-5p, miR-431-3p, miR-221-3p, miR-24-3p, miR-130a-3p, miR-339-5p, let-7i-5p) were significantly elevated in RA serum compared to HC (all p < 0.01) and 1 miRNA (miR-17-5p) was significantly lower in RA (p < 0.01). High specificity and sensitivity were determined by receiver operating characteristic (ROC) curve analysis. Both miR-339-5p and let-7i-5p were significantly reduced post-MTX (both p < 0.01). MiR-126-3p, let-7d-5p, miR-431-3p, miR-221-3p, miR-24-3p, miR-130a-3p were also significantly elevated in subjects “at risk” of developing RA (all p < 0.05) compared to HC. IPA analysis of this miRNA signature identified downstream targets including key transcription factors NF-κB, STAT-1, STAT-3, cytokines IL-1β, TNF-α, and matrix-metalloproteases all importantly associated with RA pathogenesis.

Conclusion

This study identified six miRNAs that are altered in both RA and “at-risk individuals,” which potentially regulate key downstream pathways involved in regulating inflammation. These may have potential as predictive signature for disease onset and early progression.

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.

The Expression Levels of MicroRNAs Associated with T and B Cell Differentiation/stimulation in Ankylosing Spondylitis

Spondyloarthropathies (SpAs), are a group of chronic inflammatory diseases with a number of genetic, physiopathological, clinical and radiological features. Ankylosing spondylitis (AS) is the most common type of spondylo-arthropathies, and >90.0% of patients with ankylosing spondylitis are human leukocyte antigen-B27 (HLA-B2 7)-positive. In recent years, non-HLA genetic factors have been reported to have an effect on ankylosing spondylitis. MicroRNAs (miRNAs), are endogenous non coding RNA molecules containing 18-23 nucleotides that play a role in the post-transcriptional regulation of gene expression. In this study, we aimed to determine the expression levels of miRNAs associated with T- and B-cell differentiation/stimulation in peripheral blood mononuclear cells and their relationship with the etiology of the AS in patients and healthy controls. In a molecular study, peripheral blood mononuclear cell isolation, and total RNA isolation were performed first. In the second step, cDNA synthesis and quantitative real-time PCR (qPCR) expression analysis were completed. Ultimately, in the patient and control group, the expression levels of miR-142-5p and miR-143 were found to be significantly different (p <0.05). According to current knowledge, miR-142-5p andmiR-143 expressions were found to be important for those diseases that share similar etiology with AS. We suggest that miR-142-5p and miR-143 may play a role in the pathogenesis, especially miR- 142-5p may be a potential biomarker and a target molecule for the treatment.

Neuroprotective Effects of Selective Inhibition of Histone Deacetylase 3 in Experimental Stroke

Histone deacetylase 3 (HDAC3) has been implicated as neurotoxic in several neurodegenerative conditions. However, the role of HDAC3 in ischemic stroke has not been thoroughly explored. We tested the hypothesis that selective inhibition of HDAC3 after stroke affords neuroprotection. Adult male Wistar rats (n = 8/group) were subjected to 2 h of middle cerebral artery occlusion (MCAO), and randomly selected animals were treated intraperitoneally twice with either vehicle (1% Tween 80) or a selective HDAC3 inhibitor (RGFP966, 10 mg/kg) at 2 and 24 h after MCAO. Long-term behavioral tests were performed up to 28 days after MCAO. Another set of rats (n = 7/group) were sacrificed at 3 days for histological analysis. Immunostaining for HDAC3, acetyl-Histone 3 (AcH3), NeuN, TNF-alpha, toll-like receptor 4 (TLR4), cleaved caspase-3, cleaved poly (ADP-ribose) polymerase (PARP), Akt, and TUNEL were performed. Selective HDAC3 inhibition improved long-term functional outcome (p < 0.05) and reduced infarct volume (p < 0.0001). HDAC3 inhibition increased levels of AcH3 in the ischemic brain (p = 0.016). Higher levels of AcH3 were significantly correlated with better neurological scores and smaller infarct volumes (r = 0.74, p = 0.002; r = 0.6, p = 0.02, respectively). The RGFP966 treatment reduced apoptosis-TUNEL+, cleaved caspase-3+, and cleaved PARP+ cells-and neuroinflammation-TNF-alpha+ and TLR4+ cells-in the ischemic border compared to vehicle control (p < 0.05). The RGFP966 treatment also increased Akt expression in the ipsilateral cortex (p < 0.001). Selective HDAC3 inhibition after stroke improves long-term neurological outcome and decreases infarct volume. The neuroprotective effects of HDAC3 inhibition are associated with a reduction in apoptosis and inflammation and upregulation of the Akt pathway.

Aberrant expression of miR‑130a‑3p in ankylosing spondylitis and its role in regulating T‑cell survival

Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease. MicroRNAs (miRNAs) are a group of endogenous small non‑coding RNAs that regulate target genes, and play a critical role in many biological processes. However, the underlying mechanism of specific miRNA, miR‑130a‑3p, in AS remains largely unknown. Therefore, the present study aimed to explore the underlying mechanism of miR‑130a‑3p in the development of AS. In the present study, it was revealed that miR‑130a‑3p was downregulated in T cells from HLA‑B27‑positive AS patients compared with the HLA‑B27‑negative healthy controls. Next, bioinformatics software TargetScan 7.2 was used to predict the target genes of miR‑130a‑3p, and a luciferase reporter assay indicated that HOXB1 was the direct target gene of miR‑130a‑3p. Furthermore, it was determined that HOXB1 expression was upregulated in T cells from HLA‑B27‑positive AS patients. In addition, the results of the present study indicated that miR‑130a‑3p inhibitor significantly inhibited cell proliferation ability and induced cell apoptosis of Jurkat T cells, while the miR‑130a‑3p mimic promoted proliferation ability and inhibited cell apoptosis of Jurkat T cells. Notably, all the effects of the miR‑130a‑3p mimic on Jurkat T cells were reversed by HOXB1‑plasmid. Collectively, our data indicated that miR‑130a‑3p was decreased in T cells from AS patients and it could regulate T‑cell survival by targeting HOXB1.

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.

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.

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.

Abnormal inhibition of osteoclastogenesis by mesenchymal stem cells through the miR-4284/CXCL5 axis in ankylosing spondylitis

Ankylosing spondylitis (AS) is a common inflammatory autoimmune disease, characterized by pathological osteogenesis. Mesenchymal stem cells (MSCs), as the main source of osteoblasts, participate in bone remodeling not only through differentiation into osteoblasts but also through indirect regulation of osteoclastogenesis. Our previous study indicated that the stronger osteogenic differentiation of MSCs from AS patients (ASMSCs) involved in pathological osteogenesis. However, whether there is any abnormality in the regulation of osteoclastogenesis by ASMSCs remains unclear. In this study, ASMSCs or MSCs from healthy donors (HDMSCs) were co-cultured with CD14 + monocytes in osteoclast induction medium. Our results demonstrated that ASMSCs exhibited a stronger capacity to inhibit osteoclastogenesis than HDMSCs. To explore underlying mechanisms, cytokine array assays were performed, showing that ASMSCs secreted more CXCL5 than HDMSCs, which was confirmed by enzyme-linked immunosorbent assays. Moreover, inhibition of osteoclastogenesis by ASMSCs was recovered by decreasing CXCL5. Besides, the inhibitory effect of CXCL5 on osteoclastogenesis was confirmed by exogenous addition. Bioinformatics analysis was applied to find the interaction between miR-4284 and CXCL5, which was verified by luciferase reporter assays. Furthermore, we used miR-4284 inhibitors or mimics to prove that the expression of CXCL5 was regulated by miR-4284. Further analysis showed that downregulation of miR-4284 in MSCs resulted in increase of CXCL5, markedly inhibiting osteoclastogenesis, whereas upregulation of miR-4284 in MSCs had the opposite effect. Our findings indicate that ASMSCs exhibit a stronger capacity to inhibit osteoclastogenesis than HDMSCs through the miR-4284/CXCL5 axis, which provide a new perspective on the mechanism of pathologic osteogenesis in AS.

MicroRNA-mediated immune regulation in rheumatic diseases

MicroRNAs (miRNAs) are endogenous small, non-coding RNAs that regulate genome expression at the post-transcriptional level. They are involved in a wide range of physiological processes including the maintenance of immune homeostasis and normal function. Accumulating evidence from animal studies show that alterations in pan or specific miRNA expression would break immunological tolerance, leading to autoimmunity. Differential miRNA expressions have also been documented in patients of many autoimmune disorders. In this review, we highlight the evidence that signifies the critical role of miRNAs in autoimmunity, specifically on their regulatory roles in the pathogenesis of several rheumatic diseases including systemic lupus erythematosus, rheumatoid arthritis and spondyloarthritis. The potential of miRNAs as biomarkers and therapeutic targets is also discussed. Manipulation of dysregulated miRNAs in vivo through miRNA delivery or inhibition offers promise for new therapeutic strategies in treating rheumatic diseases.

MicroRNA-130a regulates chondrocyte proliferation and alleviates osteoarthritis through PTEN/PI3K/Akt signaling pathway

The function of microRNA‑130a in development and progression of osteoarthritis was determined. In osteoarthritis patients, the serum levels of microRNA‑130a were decreased, compared with normal group. Overexpression of microRNA‑130a increased cell proliferation and decreased apoptosis of chondrocytes, and downregulation of microRNA‑130a also decreased cell proliferation and induced apoptosis in chondrocytes. Downregulation of microRNA‑130a promoted Bax and caspase‑3/9 protein expression, increased inflammation divisors and suppressed the PTEN/PI3K/Akt signaling pathway. PTEN inhibitor, VO‑Ohpic trihydrate increased the destructive effect of microRNA‑130a on cell proliferation of chondrocytes. PI3K inhibitor, wortmannin also increased the destructive effect of microRNA‑130a on osteoarthritis. In conclusion, microRNA‑130a is an important regulator of osteoarthritis in chondrocytes through PTEN/PI3K/Akt signaling pathway.

MicroRNA implications in the etiopathogenesis of ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic immune-mediated inflammatory disease that affects both axial and peripheral skeletons as well as soft tissues. Recent investigations offer that disease pathogenesis is ascribed to a complex interplay of genetic, environmental, and immunological factors. Until now, there is no appropriate method for early diagnosis of AS and the successful available therapy for AS patients stay largely undefined. MicroRNAs (miRNAs), endogenous small noncoding RNAs controlling the functions of target mRNAs and cellular processes, are present in human plasma in a stable form and have appeared as possible biomarkers for activity, pathogenesis, and prognosis of the disease. In the present review, we have tried to summarize the recent findings related to miRNAs in AS development and discuss the possible utilization of these molecules as prognostic biomarkers or important therapeutic strategies for AS. Further examinations are needed to determine the unique miRNAs signatures in AS and characterize the mechanisms mediated by miRNAs in the pathology of this disease.

Intermittent Fasting Protects against Alzheimer's Disease Possible through Restoring Aquaporin-4 Polarity

The impairment of amyloid-β (Aβ) clearance in the brain plays a causative role in Alzheimer's disease (AD). Polarity distribution of aquaporin-4 (AQP4) is important to remove Aβ from brain. AQP4 polarity can be influenced by the ratio of two AQP4 isoforms M1 and M23 (AQP4-M1/M23), however, it is unknown whether the ratio of AQP4-M1/M23 changes in AD. Histone deacetylase 3 has been reported to be significantly increased in AD brain. Moreover, evidence indicated that microRNA-130a (miR-130a) possibly mediates the regulation of histone deacetylase 3 on AQP4-M1/M23 ratio by repressing the transcriptional activity of AQP4-M1 in AD. This study aimed to investigate whether intermittent fasting (IF), increasing the level of an endogenous histone deacetylases inhibitor β-hydroxybutyrate, restores AQP4 polarity via miR-130a mediated reduction of AQP4-M1/M23 ratio in protection against AD. The results showed that IF ameliorated cognitive dysfunction, prevented brain from Aβ deposition, and restored the AQP4 polarity in a mouse model of AD (APP/PS1 double-transgenic mice). Additionally, IF down-regulated the expression of AQP4-M1 and histone deacetylase 3, reduced AQP4-M1/M23 ratio, and increased miR-130a expression in the cerebral cortex of APP/PS1 mice. In vitro, β-hydroxybutyrate was found to down-regulate the expression of AQP4-M1 and histone deacetylase 3, reduce AQP4-M1/M23 ratio, and increase AQP4-M23 and miR-130a expression in 2 μM Aβ-treated U251 cells. Interestingly, on the contrary to the result observed in 2 μM Aβ-treated cells, AQP4 expression was obviously decreased in cells exposed to 10 μM Aβ. miR-130a mimic decreased the expression of AQP4-M1 and the ratio of AQP4-M1/M23, as well as silencing histone deacetylase 3 caused the up-regulation of AQP4 and miR-130a, and the reduction of AQP4-M1/M23 ratio in U251 cells. In conclusion, IF exhibits beneficial effects against AD. The mechanism may be associated with recovery of AQP4 polarity, resulting from the reduction of AQP4-M1/M23 ratio. Furthermore, β-hydroxybutyrate may partly mediate the effect of IF on the reduction of AQP4-M1/M23 ratio in AD, in which miR-130a and histone deacetylase 3 may be implicated.

MicroRNA-130b transcriptionally regulated by histone H3 deacetylation renders Akt ubiquitination and apoptosis resistance to 6-OHDA

Apoptosis of DA neurons is a contributing cause of disability and death for Parkinson's disease (PD). Akt may become a potential therapeutic target for PD since Akt has been deactivated during DA neuron apoptosis. We previously demonstrated that Akt confers apoptosis resistance against 6-OHDA in DA neuron-like PC12 cells, yet the underlying mechanisms accounted for this are not fully understood. Here we report that microRNA-130b (miR-130b)-dependent and cylindromatosis (CYLD) repression-mediated Akt ubiquitination renders apoptosis resistance of PC12 cells to 6-OHDA, which elicits histone H3 deacetylation-induced transcriptional downregulation of miR-130b vice versa. CYLD deficiency ubiquitinates Akt at Lys63, thereby phosphorylating Akt and antagonizing 6-OHDA-initiated apoptosis. MiR-130b targetedly represses CYLD and increases apoptosis resistance to 6-OHDA. CYLD repression by miR-130b restores Akt ubiquitination and activation, GSK3β and FoxO3a phosphorylation, FoxO3a removal from Bim promoter as well as Bim downregulation during 6-OHDA administration. CYLD deficiency-mediated Akt activation is instrumental for the apoptosis-resistant phenotypes of miR-130b. In addition, 6-OHDA transcriptionally downregulates miR-130b through recruitment of HDAC3 at the promoter. Furthermore, EPO potentiates the ability of miR-130b to activate Akt and augment apoptosis resistance. Our findings identify the apoptosis-resistant function of miR-130b and suggest that histone H3 deacetylation plays a pivotal role in regulating miR-130b transcription in response to 6-OHDA.

New insights toward the pathogenesis of ankylosing spondylitis; genetic variations and epigenetic modifications

Ankylosing spondylitis (AS) is a chronic inflammatory autoimmune disease, characterized by typically an axial arthritis. AS is the prototype of a group of disorders called spondyloarthropathies, which is believed to have common clinical manifestations and genetic predisposition. To date, the exact etiology of AS remains unclear. Over the past few years, however, the role of genetic susceptibility and epigenetic modifications caused through environmental factors have been extensively surveyed with respect to the pathogenesis of AS, resulted in important advances. This review article focuses on the recent advances in the field of AS research, including HLA and non-HLA susceptibility genes identified in genome-wide association studies (GWAS), and aberrant epigenetic modifications of gene loci associated with AS. HLA genes most significantly linked with AS susceptibility include HLA-B27 and its subtypes. Numerous non-HLA genes such as those in ubiquitination, aminopeptidases and MHC class I presentation molecules like ERAP-1 were also reported. Moreover, epigenetic modifications occurred in AS has been summarized. Taken together, the findings presented in this review attempt to explain the circumstance by which both genetic variations and epigenetic modifications are involved in triggering and development of AS. Nonetheless, several unanswered dark sides continue to clog our exhaustive understanding of AS. Future researches in the field of epigenetics should be carried out to extend our vision of AS etiopathogenesis.

The Role of MicroRNAS in Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a common and genetically heterozygous inflammatory rheumatic disease characterized by new bone formation, ankylosis and inflammation of hip, sacroiliac joints and spine. Until now, there is no method for early diagnosis of AS and the effective treatment available for AS patients remain largely undefined.We searched articles indexed in PubMed (MEDLINE) database using Medical Subject Heading (MeSH) or Title/Abstract words ("microRNA" and "ankylosing spondylitis") from inception up to November 2015.Genetic polymorphisms of miRNAs and their targets might alter the risk of AS development whereas certain miRNAs exhibit correlation with inflammatory index.Let-7i and miR-124 were upregulated whereas miR-130a was downregulated in circulating immune cells of AS patients. These deregulated miRNAs could modulate key immune cell functions, such as cytokine response and T-cell survival.miRNA deregulation is key to AS pathogenesis. However, clinical utilization of miRNAs for management of AS patients requires further support from future translational studies.