Higher expression of whole blood microRNA-21 in patients with ankylosing spondylitis associated with programmed cell death 4 mRNA expression and collagen cross-linked C-telopeptide concentration

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.

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.

A case report of primary biliary cholangitis combined with ankylosing spondylitis

RATIONALE

A chronic autoimmune liver disease known as primary biliary cholangitis (PBC) that selectively destructs small intrahepatic biliary epithelial cells and may result in biliary cirrhosis and eventually liver transplantation or death. PBC is associated with various other extrahepatic autoimmune diseases; however, the combination of PBC with ankylosing spondylitis has been rarely reported in the literature. Here, we reported a case of PBC with ankylosing spondylitis to improve our understanding of such coexistence and provide new ideas for the treatment of such patients.

PATIENT CONCERNS

A 54-year-old man was presented to the Department of Rheumatology because of an abnormal liver function test for 7 years, chest and back pain for 1 year, and low back pain for 2 months.

DIAGNOSES

Primary biliary cholangitis, ankylosing spondylitis, and old pulmonary tuberculosis.

INTERVENTIONS

The patient refused to use nonsteroidal anti-inflammatory drugs, conventional synthetic disease-modifying antirheumatic drugs, and biologic disease-modifying antirheumatic drugs; thus, he was treated with methylenediphosphonate (99Tc-MDP) and ursodeoxycholic acid (UDCA).

OUTCOMES

The patient achieved remission with UDCA and 99Tc-MDP therapy.

LESSONS

In the treatment of PBC combined with other disorders, the characteristics of different diseases should be considered. The patient reported herein was treated with 99Tc-MDP and UDCA, and his condition improved; thus, we consider 99Tc-MDP to be an effective treatment. Furthermore, in line with the current understanding of the pathogenesis of PBC and ankylosing spondylitis, we hypothesize that interleukin-17 inhibitor is an effective treatment for such patients.

The role of miRNAs in Behçet's disease

The symptoms of Behçet's disease (BD), a multisystemic condition with autoimmune and inflammation as hallmarks, include arthritis, recurring oral and vaginal ulcers, skin rashes and lesions, and involvement of the nervous, gastrointestinal, and vascular systems. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), may be important regulators of inflammation and autoimmune disease. These ncRNAs are essential to the physiological and pathophysiological disease course, and miRNA in particular has received significant attention for its role and function in BD and its potential use as a diagnostic biomarker in recent years. Although promising as therapeutic targets, miRNAs must be studied further to fully comprehend how miRNAs in BD act biologically.

The study of the effect of HLA-B27 on THP-1 monocytic cells survival and its mechanism

OBJECTIVE

Previous studies have shown that human leukocyte antigen (HLA)-B27 induces the accumulation of unfolded proteins in the endoplasmic reticulum (ER) to cause ER stress, resulting in the unfold protein response (UPR), apoptosis and autophagy. However, it is still unknown whether it affects the survival of monocytes. In this study, we attempted to examine the effect of HLA-B27 gene knockout on the proliferation and apoptosis of THP-1 monocytic cell line and its potential mechanism.

METHODS

HLA-B27 gene knockout THP-1 cell line was constructed by lentivirus infection, and knockout efficiency was detected by immunofluorescence, quantitative reverse transcription - polymerase chain reaction (qRT-PCR) and western blot. Cell Counting Kit-8 (CCK-8) method and Annexin-V/PI double staining were used to detect the proliferation and apoptosis of the constructed THP-1 cell line, respectively. qRT-PCR was used to detect the effect of HLA-B27 inhibition on the expressions of ER molecular chaperone binding immunoglobulin protein (BiP) and genes about the UPR pathway. The proliferation rate of human BiP protein-stimulated THP-1 cells was detected by CCK-8 method.

RESULTS

HLA-B27 gene knockout THP-1 cells were successfully constructed by lentivirus infection. Knockout of HLA-B27 effectively promoted the proliferation of THP-1 cells and inhibited the apoptosis induced by cisplatin. qRT-PCR showed that BiP was synchronously increased, while activation of UPR pathway was inhibited. Stimulation with human BiP promoted the proliferation of THP-1 cells in a concentration-dependent manner.

CONCLUSIONS

HLA-B27 inhibition can promote the proliferation and inhibit the apoptosis of THP-1 cells. The inhibition function may be achieved through promotion of BiP and inhibition of UPR pathway activation.

Association of vascular endothelial growth factor serum levels with ankylosing spondylitis in Egyptian patients

Background

Ankylosing spondylitis (AS) is one of inflammatory rheumatic diseases which result in wide range of manifestations on the musculoskeletal system and axial joint specifically. Endothelial cell migration and proliferation, as well as subsequent neoangiogenesis and remodelling in autoimmune disorders, are pathogenic mechanisms that are fundamental to inflammation activation and angiogenesis. The development of advanced lesions is thought to involve vascular proliferation as well as vascular endothelial growth factor (VEGF), which serves a regulatory role. It was found that AS patients had increased serum levels of VEGF, which were linked to the disease activity.

Aim of the work

The purpose of this study is to measure serum VEGF levels in Egyptian AS patients and assess their relation to disease-related variables, including radiographic findings.

Results

VEGF serum levels showed a highly significant positive correlation with Bath Ankylosing Spondylitis Functional Index (BASFI) and modified Stroke Ankylosing Spondylitis Spinal Score (MSASS) (p < 0.001); also, there was a significant correlation between the VEGF values and the Ankylosing Spondylitis Disease Activity Index (ASDAS) and the New York x-ray sacroiliac score.

Conclusions

These findings and data illustrate the strong relationship between ASDAS and VEGF and the radiographic score in AS patients. ASDAS combined with VEGF not only is considered a tool for determining the level of disease activity only but also is considered as an indicator for the assessment of the syndesmophytes formation, which performs a crucial role in the prognosis and outcome in AS patients.

Identification of diagnostic mRNA biomarkers in whole blood for ankylosing spondylitis using WGCNA and machine learning feature selection

Ankylosing spondylitis (AS) is a common inflammatory spondyloarthritis affecting the spine and sacroiliac joint that finally results in sclerosis of the axial skeleton. Aside from human leukocyte antigen B27, transcriptomic biomarkers in blood for AS diagnosis still remain unknown. Hence, this study aimed to investigate credible AS-specific mRNA biomarkers from the whole blood of AS patients by analyzing an mRNA expression profile (GSE73754) downloaded Gene Expression Omnibus, which includes AS and healthy control blood samples. Weighted gene co-expression network analysis was performed and revealed three mRNA modules associated with AS. By performing gene set enrichment analysis, the functional annotations of these modules revealed immune biological processes that occur in AS. Several feature mRNAs were identified by analyzing the hubs of the protein-protein interaction network, which was based on the intersection between differentially expressed mRNAs and mRNA modules. A machine learning-based feature selection method, SVM-RFE, was used to further screen out 13 key feature mRNAs. After verifying by qPCR, IL17RA, Sqstm1, Picalm, Eif4e, Srrt, Lrrfip1, Synj1 and Cxcr6 were found to be significant for AS diagnosis. Among them, Cxcr6, IL17RA and Lrrfip1 were correlated with severity of AS symptoms. In conclusion, our findings provide a framework for identifying the key mRNAs in whole blood of AS that is conducive for the development of novel diagnostic markers for AS.

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.

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.

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.

miR-21 may Act as a Potential Mediator Between Inflammation and Abnormal Bone Formation in Ankylosing Spondylitis Based on TNF-α Concentration-Dependent Manner Through the JAK2/STAT3 Pathway

Objective:

To explore the role of microRNA (miR-21) in new bone formation in ankylosing spondylitis (AS) as mediated by different concentration of tumor necrosis factor-α (TNF-α).

Methods:

Fibroblasts isolated from the hips of patients with AS were induced to osteogenesis. These cells were then stimulated with varying concentrations of TNF-α. MicroRNA-21 expressions were evaluated using reverse transcription–polymerase chain reaction (RT-PCR) and osteogenesis was detected via Alizarin Red S (ARS) staining and measurement of alkaline phosphatase (ALP) activity. Relative expressions of p-STAT3, Nuclear STAT3, cytoplasm STAT3, Runx2, BMP2, osteopontin, osteocalcin, and LC3B in AS fibroblasts were measured after exposure to different concentrations of TNF-α. The STAT3-inhibiting small interfering RNA allowed further exploration on its impact on miR-21 and primary miR-21 expressions. A proteoglycan-induced arthritis (PGIA) Balb/c mouse model was established in order to monitor sacroiliac joint (SIJ) inflammation and subsequent damage through magnetic resonance image. Serum miR-21 and TNF-α expressions were evaluated using RT-PCR and enzyme-linked immunosorbent assay. At week 16, mice models were transfected intravenously with miR-21 overexpressing agomir and miR-21 inhibiting antagomir for 7 successive days. The rate of abnormal bone formation at SIJ was evaluated using microcomputed tomography and hematoxylin and eosin staining at week 24. Western blot analysis enabled quantification of STAT-3, JAK-2, and interleukin (IL)-17A expressions present in the SIJ.

Results:

The in vitro miR-21 expression and osteogenesis activity were noted to be augmented in the setting of low TNF-α concentrations (0.01-0.1 ng/mL) while they were depressed in settings with higher TNF-α concentrations (1-10 ng/mL). Samples with the most distinct ARS manifestation and ALP activity as well as the highest miR-21 expressions were those who received 0.1 ng/mL of TNF-α. Primary miR-21 was found to be notable raised by Si-STAT3, while the converse effect was seen in mature miR-21 expressions. Intravenous injection of exogenous miR-21 contributed to new bone formation and significantly elevated expressions of STAT3, JAK2, and IL-17 in PGIA mice.

Conclusions:

The results revealed that miR-21 may act as a potential mediator between new bone formation and inflammation in AS.

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 3ʹ 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.

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.

Serum miR-21 expression correlates with radiographic progression but also low bone mineral density in patients with ankylosing spondylitis: a cross-sectional study

Increased expressions of miR-21 have been detected in ankylosing spondylitis (AS) patients. The current study was performed to examine the serum miR-21 expression with radiographic severity in AS patients, which was determined based on the modified New York (NY) criteria for sacroiliac joints assessment and modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) system for spine involvement. Bone mineral density at lumbar 1–4 and femoral neck were examined by dual-energy absorptiometry (DXA). Serum miR-21 expressions were determined by quantitative real-time PCR, and receiver operating characteristic curve analysis was performed to identify the diagnostic value of miR-21 expression levels regarding the NY criteria. Elevated levels of serum miR-21 expressions were detected in AS patients compared with healthy controls. AS patients with modified NY grade 4 showed significantly higher miR-21 expression than grade 3 and grade 2. AS patients with spinal syndesmophytes had significantly higher serum miR-21 expressions than non-syndesmophyte patients. Increased miR-21 expressions were significantly related to the disease radiographic severity. In addition, serum miR-21 expressions were negatively associated with lumbar 1–4 and femoral neck bone mineral density. In summary, serum miR-21 expressions were related to structural damage and radiological progression in AS, indicating that miR-21 may act as a switch between inflammation and new bone information and regulate different signal ways between lesioned enthesis and trabecular bone.

Deregulation of microRNA expression in monocytes and CD4+ T lymphocytes from patients with axial spondyloarthritis

Background

MicroRNAs (MiRs) play an important role in the pathogenesis of chronic inflammatory diseases. This study is the first to investigate miR expression profiles in purified CD4⁺ T lymphocytes and CD14⁺ monocytes from patients with axial spondyloarthritis (axSpA) using a high-throughput qPCR approach.

Methods

A total of 81 axSpA patients fulfilling the 2009 ASAS classification criteria, and 55 controls were recruited from October 2014 to July 2017. CD14⁺ monocytes and CD4⁺ T lymphocytes were isolated from peripheral blood mononuclear cells. MiR expression was investigated by qPCR using the Exiqon Human MiRnome panel I analyzing 372 miRNAs. Differentially expressed miRNAs identified in the discovery cohort were validated in the replication cohort.

Results

We found a major difference in miR expression patterns between T lymphocytes and monocytes regardless of the patient or control status. Comparing disease-specific differentially expressed miRs, 13 miRs were found consistently deregulated in CD14⁺ cells in both cohorts with miR-361-3p, miR-223-3p, miR-484, and miR-16-5p being the most differentially expressed. In CD4⁺ T cells, 11 miRs were differentially expressed between patients and controls with miR-16-1-3p, miR-28-5p, miR-199a-5p, and miR-126-3p were the most strongly upregulated miRs among patients. These miRs are involved in disease relevant pathways such as inflammation, intestinal permeability or bone formation. Mir-146a-5p levels correlated inversely with the degree of inflammation in axSpA patients.

Conclusions

We demonstrate a consistent deregulation of miRs in both monocytes and CD4⁺ T cells from axSpA patients, which could contribute to the pathophysiology of the disease with potential interest from a therapeutic perspective.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1829-7) contains supplementary material, which is available to authorized users.

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.

Predisposition of six well-characterized microRNAs to syndesmophytes among Chinese patients with ankylosing spondylitis

OBJECTIVES

We quantified the expression of six well-characterized microRNAs (miRNAs) in peripheral blood mononuclear cells to see whether they can predispose to syndesmophytes in ankylosing spondylitis (AS) patients.

METHODS

This is a cross-sectional study involving 46 AS patients (23/23 with/without syndesmophytes) and 22 healthy controls. miRNAs expression was quantified by real-time PCR.

RESULTS

Six examined miRNAs were comparably expressed between AS patients without syndesmophytes and healthy controls (p > .05). Relative to AS patients without syndesmophytes, patients with syndesmophytes had significantly higher levels of miR-29a, miR-335-5p, miR-27a and let-7i (p = .001, .002, .013 and .029, respectively). Nine significant contributors associated with syndesmophytes in AS, including smoking, AS duration, human leukocyte antigen B27, erythrocyte sedimentation rate, C-reactive protein, miR-335-5p, miR-27a, miR-218 and sacroiliitis, were identified. The addition of miR-335-5p, miR-27a and miR-218 can significantly improve the accuracy of baseline risk factors. Based on the nine significant contributors, a nomogram was constructed, with good prediction accuracy (C-index: 0.86, p < .001).

CONCLUSION

We provide evidence for the predisposition of miR-335-5p, miR-27a and miR-218 to syndesmophytes in AS patients, indicating a contributory role of miRNAs in the pathogenesis of syndesmophytes. Further validation is warranted.

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.

Predictive value of microRNA-132 and its target gene NAG-1 in evaluating therapeutic efficacy of non-steroidal anti-inflammatory drugs treatment in patients with ankylosing spondylitis

Ankylosing spondylitis (AS) is a common chronic rheumatic disorder, accompanied by the differential expression of various microRNAs (miRNAs) in patients suffering from the condition, some of which have the potential to serve as novel complementary AS biomarkers. During this study, AS patients were recruited in connection with our investigation into the correlation of microRNA-132 (miR-132) in peripheral blood and its target gene NAG-1 expressions in relation with the clinical efficacy of non-steroidal anti-inflammatory drugs (NSAIDs) treatment in patients with AS. A total of 218 AS patients who had been previously treated with oral diclofenac sodium and were placed into either the response (n = 175) or non-response groups (n = 43) following a 16-week period of therapeutic evaluation. An additional 113 healthy patients were also recruited for the purposes of the study. AS patient peripheral blood samples were obtained at the 0th, 8th, and 16th week, with the corresponding samples of the healthy patients collected at week 0. The expressions of miR-132 and NAG-1 were detected by RT-qPCR and analyzed using a ROC curve for the elucidation of the diagnostic value of peripheral blood miR-132 expressions as well as their predictive value among AS patients undergoing NSAIDs treatment. The targeting relations of miR-132 and NAG-1 were validated by microRNA.org and luciferase assay. Greater levels of peripheral blood miR-132 expression were observed among AS patients prior to treatment, in comparison to the healthy patients in the study. Prior to treatment, the area under the miR-132 ROC curve (AUC) of AS patients was 0.965, with a critical point of 2.605. The sensitivity and specificity of miR-132 were 91.7 and 97.3%, respectively, in regard to the AS diagnostic clinical efficacy. In comparison with the non-response group, the miR-132 expression of patients in the response group exhibited descended levels while the mRNA expression of NAG-1 increased. The ROC results indicated that the AUC of miR-132 was 0.876 with its sensitivity and specificity observed to be 95.3 and 80.0%, respectively. The AUC of NAG-1 was 0.912 with its sensitivity and specificity observed to be 76.6 and 79.1%, respectively. In comparison with the high miR-132 expression group and the low NAG-1 mRNA expression group, significantly improved blood biochemistry indexes, sign indexes, blood indexes, and adverse reaction rate were observed among the low miR-132 expression group and the high NAG-1 mRNA expression group. The microRNA.org and luciferase assay revealed NAG-1 to be a target of miR-132. Based on the results of this study, it was concluded that the expressions of MiR-132 and NAG-1 could serve as biological markers in the prediction of the therapeutic efficiency of NSAID treatment in AS patients.

Identification of potential target genes for ankylosing spondylitis treatment

This study aimed to identify the potential target genes for the treatment of ankylosing spondylitis (AS).Dataset GSE25101 was downloaded from Gene Expression Omnibus, including 16 AS and 16 normal control blood samples. Differentially expressed genes (DEGs) were identified using unmatched t-test in limma package with adjusted P < .05. Gene ontology-biological process (GO-BP) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted using multifaceted analysis tool for human transcriptome. Protein-protein interaction (PPI) network was constructed using STRING and Cytoscape, and module analysis was performed using MCODE plug-in. Webgestal was utilized to predict transcriptional factor (TF)-microRNA-target network and Comparative Toxicogenomics Database (CTD) was applied to predict chemical-target network.A total of 334 DEGs were identified, including 136 upregulated genes and 198 downregulated genes. According to STRING, a PPI network was constructed and 1 significant clustered module was screen out with score = 6.33. MAPK7 (degree = 11) and NDUFS4 (degree = 10) were 2 important nodes in PPI network, and both of them were significantly enriched in cAMP mediated signaling pathway (P = 2.02E-02). MAPK7 could be regulated by NFY. Both MAPK7 and NDUFS4 were 2 potential targets for Indomethacin.MAPK7 and NDUFS4 played important roles in the pathogenesis of AS via cAMP mediated signaling pathway. Both of them could be targeted by Indomethacin.

Ankylosing spondylitis: beyond genome-wide association studies

PURPOSE OF REVIEW

This article discusses genomic investigations in ankylosing spondylitis (AS) beyond genome-wide association (GWA) studies, but prior to this, genetic variants achieving genome-wide significance will be summarized highlighting key pathways contributing to disease pathogenesis.

RECENT FINDINGS

Evidence suggests that disease pathogenesis is attributed to a complex interplay of genetic, environmental and immunological factors. GWA studies have greatly enhanced our understanding of AS pathogenesis by illuminating distinct immunomodulatory pathways affecting innate and acquired immunity, most notably the interleukin-23/interleukin-17 pathway. However, despite the wealth of new information gleaned from such studies, a fraction of the heritability (24.4%) has been explained. This review will focus on investigations beyond GWA studies including copy number variants, gene expression profiling, including microRNA (miRNA), epigenetics, rare variants and gene-gene interactions.

SUMMARY

To address the 'missing heritability' and advance beyond GWA studies, a concerted effort involving rethinking of study design and implementation of newer technologies will be required. The coming of age of next-generation sequencing and advancements in epigenetic and miRNA technologies, combined with familial-focused investigations using well-characterized cohorts, is likely to reveal some of the hidden genomic mysteries associated with AS.

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.

Micro-Ribonucleic Acid Profiles From Microarray in Ankylosing Spondylitis

Objectives

This study aims to detect candidate micro-ribonucleic acids (miRNAs) from microarray within peripheral blood mononuclear cells and synovial fluid mononuclear cells in patients with ankylosing spondylitis (AS).

Patients and methods

Samples from three AS patients (3 males, mean age 37.3±2.5 years; range 35 to 40 years) and three healthy controls (3 males, mean age 39.0±2.6 years; range 37 to 42 years) were obtained for miRNA microarray. The microarray experiment proceeded only when the quality of total RNAs were considered to have "passed", and their integrity was good by total RNA quality control using Agilent Bioanalyzer 2100. Hierarchical clustering was performed to understand the impact of the storage condition on the miRNA expression profiles. MiScript primer assays were used for semiquantitative determination of the expression of human miRNAs to validate results from miRNA microarray.

Results

A total of 887 miRNAs were screened by microarray among groups. After normalization of the raw data, we noted that the expression of five miRNAs was significantly lower (fold change ≤0.5 and p≤0.05) and only hsa-miR-424-5p was significantly higher in AS peripheral blood mononuclear cell (fold change ≥2 and p≤0.05). In AS synovial fluid mononuclear cells, we identified that expressions of 16 miRNAs were significantly down regulated whereas only hsa-miR-424-5p was significantly upregulated (fold change ≥2 and p≤0.05). All above-mentioned miRNAs were reevaluated for further validation. Finally, significantly increased hsa-miR-424-5p and decreased hsa-miR-377 were found in synovial fluid mononuclear cells from AS patients compared with healthy controls. Based on target prediction programs and published papers, potential target genes and its pathways were screened.

Conclusion

miR-424-5p was increased and miR-377 was decreased in synovial fluid mononuclear cells from patients with AS. These two miRs might have functional roles in patients with arthritis via different pathways.

Disorders of MicroRNAs in Peripheral Blood Mononuclear Cells: As Novel Biomarkers of Ankylosing Spondylitis and Provocative Therapeutic Targets

Background. MicroRNAs can potentially regulate every aspect of cellular activity. In this study, we investigated whether AS pathogenesis involves microRNAs disorders. Result. The expression of 2 microRNAs, hsa-miR-126-3p and hsa-miR-29a, was significantly lower in active AS group before etanercept therapy than in control group. Marched fold changes of them were 3.76 and 16.22. Moreover, expressions of hsa-miR-126-3p and hsa-miR-29a were dramatically upregulated after 12-weeks etanercept treatment. Fold changes were 2.20 and 3.18. All regulations of microRNAs expression mentioned before were statistically significant (fold change >2 and P < 0.05). The expression disorders of the 2 microRNAs did not statistically significantly correlated with BASDAI, CRP, and ESR. Conclusion. AS pathogenesis involved dysregulation of microRNAs. Hsa-miR-126-3p and hsa-miR-29a will probably become the potential biomarkers and provocative therapeutic targets of AS.