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

MicroRNA Let-7i Regulates Innate TLR4 Pathways in Peripheral Blood Mononuclear Cells of Patients with Ankylosing Spondylitis

Purpose

This study aimed to compare the changes in the expression of microRNA Let-7i in peripheral blood mononuclear cells (PBMCs) of patients with ankylosing spondylitis (AS) and the correlation between Let-7i and innate pro-inflammatory factors. It is necessary to search for a new biomarker to guide the prognosis of AS.

Methods

A total of 10 patients with AS and 10 healthy volunteers were selected as AS and control groups, respectively. The expression levels of Let-7i, Toll-like receptor 4 (TLR4), nuclear factor-κB (NF-κB), and interferon-gamma (IFN-γ) in PBMCs were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting (WB) to explore the relationship between Let-7i and pro-inflammatory factors. Furthermore, the relationship between Let-7i and TLR4 was determined by the luciferase reporter technology.

Results

The expression level of Let-7i in PBMCs of patients with AS was significantly lower than that of healthy control. The expression levels of TLR4, NF-κB, and IFN-γ in PBMCs derived from patients with AS were significantly higher than those of healthy control. The results show that Let-7i manipulation can regulate lipopolysaccharide (LPS)-induced TLR4 and IFN-γ expression in CD4+ T cells of patients with AS. The overexpression of Let-7i in T cells of patients with AS can suppress TLR4 and IFN-γ LPS-induced expression levels of cellular mRNA and protein. Let-7i can directly interfere TLR4-3'untranslated region (UTR) sequence and regulate the expression of the TLR4 gene in Jurkat T cells.

Conclusion

Let-7i may be involved in the pathogenesis of AS, and Let-7i expression in PBMCs may be helpful for the diagnosis and treatment of AS in the future.

The Potential Role of Genetics, Environmental Factors, and Gut Dysbiosis in the Aberrant Non-Coding RNA Expression to Mediate Inflammation and Osteoclastogenic/Osteogenic Differentiation in Ankylosing Spondylitis

Ankylosing spondylitis (AS) or radiographic axial spondyloarthritis is a chronic immune-mediated rheumatic disorder characterized by the inflammation in the axial skeleton, peripheral joints, and soft tissues (enthesis, fascia, and ligament). In addition, the extra-skeletal complications including anterior uveitis, interstitial lung diseases and aortitis are found. The pathogenesis of AS implicates an intricate interaction among HLA (HLA-B27) and non-HLA loci [endoplasmic reticulum aminopeptidase 1 (ERAP1), and interleukin-23 receptor (IL23R), gut dysbiosis, immune plasticity, and numerous environmental factors (infections, heavy metals, stress, cigarette smoking, etc.) The latter multiple non-genetic factors may exert a powerful stress on epigenetic regulations. These epigenetic regulations of gene expression contain DNA methylation/demethylation, histone modifications and aberrant non-coding RNAs (ncRNAs) expression, leading to inflammation and immune dysfunctions. In the present review, we shall discuss these contributory factors that are involved in AS pathogenesis, especially the aberrant ncRNA expression and its effects on the proinflammatory cytokine productions (TNF-α, IL-17 and IL-23), T cell skewing to Th1/Th17, and osteoclastogenic/osteogenic differentiation. Finally, some potential investigatory approaches are raised for solving the puzzles in AS pathogenesis.

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.

Biomarkers in axial spondyloarthritis and low back pain: a comprehensive review

The spectrum of axial spondyloarthritis (AxSpA) (including both non-radiographic and radiographic AxSpA), also known as ankylosing spondylitis AS, has achieved growing recognition. With the development of treatments not only effective in controlling disease activity but also in slowing radiographic progression, and given the cost and risk profiles of these novel treatments and the limitations of current clinical criteria, imaging and peripheral blood biomarkers (C-reactive protein, HLA-B27 testing), the need for better biomarkers has never been greater. The purpose of this review is to present up-to-date information on the biomarkers for the diagnosis for assessing disease diagnosis, activity, treatment response, and radiographic progression of AxSpA, and entails multiple search strings used to identify articles of interest published in PubMed and the Cochrane database up to May 1, 2021. We present the current status of research in serologic biomarkers such as cytokines, adipokines, matrix metalloproteinases, calprotectin, CD74, antibodies, bone turnover markers, and circulating protein fragments of cartilage and connective tissue degradation and other biomarkers. Despite a great deal of work, most serologic results have been disappointing and to date none perform better than CRP. Recent promising preliminary data for some has been published, but require further confirmation. Transcriptomic biomarkers such as micro-RNAs and genetic biomarkers also show promise to assist in diagnosis and possibly for radiographic severity, including a recently developed panel of genetic risk markers used in a polygenic risk score instrument in AS diagnosis. These need further confirmation and application in AS as well as in nr-AxSpA.

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.

miRNA-451a and miRNA-125a Expression Levels in Ankylosing Spondylitis: Impact on Disease Diagnosis, Prognosis, and Outcomes

Background

Early diagnosis of ankylosing spondylitis (AS) is yet not elucidated, with a potential diagnostic glance of microRNAs (miRNAs).

Aim

Study the expression profile of miRNA-451a and miRNA-125a in AS patients and their impact on disease activity and prognosis.

Methods

A cross-sectional study included 55 AS patients diagnosed according to modified New York criteria in 1984 with 55 matched healthy controls. History, clinical examination, and disease activity assessment with Bath ankylosing spondylitis disease activity index (BASDAI) were done. Full laboratory and radiological assessment along with expression profile of m iRNA-451a and miRNA-125a were tabulated and analyzed.

Results

Higher expression levels of miRNA-125a and lower of miRNA-451a in AS patients compared to controls. Furthermore, miRNA-125a expression was high in active AS patients compared to inactive patients and controls (7.0 ± 3.4 vs. 4.1 ± 2.1 vs. 2.6 ± 0.6, p < 0.001, respectively). miRNA-451a was significantly lower in active AS patients compared to inactive patients and controls (2.2 ± 1.1 vs. 4.1 ± 2.3 vs. 7.1 ± 4.5, respectively). Both miRNAs (miRNA-125a and miRNA-451a) had evident accuracy for AS diagnosis with areas under the curve (AUC) of 0.788 and 0.802, respectively. miRNA-125a had potential impact on AS activity with AUC of 0.777. Plasma levels of both miRNAs were able to distinguish AS patients with structural damage with AUCs 0.775 and 0.692, respectively.

Conclusions

Both miRNA-451a and miRNA-125a were found to be of great value as sensitive noninvasive diagnostic, prognostic, and disease burden biomarker of AS patients in Egypt with suggested further studies for future therapeutic implications.

lncRNA MEG3 Suppresses the Progression of Ankylosis Spondylitis by Regulating the Let-7i/SOST Axis

Ankylosis spondylitis (AS) is a disease mainly characterized by sacroiliac joint and spinal attachment point inflammation. Long non-coding RNA (lncRNA) plays a key role in the progression of many diseases. However, few studies have been conducted on the function of lncRNA maternally expressed gene 3 (MEG3) in AS. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure the relative levels of MEG3, microRNA let-7i, sclerostin (SOST), and inflammatory cytokines. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and biotin-labeled RNA pull-down assay were used to confirm the interaction between MEG3 and let-7i or let-7i and SOST. In addition, western blot (WB) analysis was performed to detect the protein levels of osteogenesis markers and SOST. The expression levels of MEG3 and SOST were decreased and let-7i was increased in AS patients. MEG3 could interact with let-7i in AS fibroblasts, and let-7i overexpression reversed the suppressive effect of MEG3 upregulation on the inflammation and bone formation of AS. Additionally, let-7i could target SOST, and SOST silencing reversed the inhibitory effect of let-7i inhibitor or MEG3 overexpression on the inflammation and bone formation of AS. Furthermore, SOST expression was positively regulated by MEG3, while was negatively regulated by let-7i. Our results revealed that lncRNA MEG3 promoted SOST expression to restrain the progression of AS by sponging let-7i, which provided a treatment target for AS.

Biomarker development for axial spondyloarthritis

The term axial spondyloarthritis (axSpA) encompasses a heterogeneous group of diseases that have variable presentations, extra-articular manifestations and clinical outcomes, and that will respond differently to treatments. The prototypical type of axSpA, ankylosing spondylitis, is thought to be caused by interaction between the genetically primed host immune system and gut microbiota. Currently used biomarkers such as HLA-B27 status, C-reactive protein and erythrocyte sedimentation rate have, at best, moderate diagnostic and predictive value. Improved biomarkers are needed for axSpA to assist with early diagnosis and to better predict treatment responses and long-term outcomes. Advances in a range of 'omics' technologies and statistical approaches, including genomics approaches (such as polygenic risk scores), microbiome profiling and, potentially, transcriptomic, proteomic and metabolomic profiling, are making it possible for more informative biomarker sets to be developed for use in such clinical applications. Future developments in this field will probably involve combinations of biomarkers that require novel statistical approaches to analyse and to produce easy to interpret metrics for clinical application. Large publicly available datasets from well-characterized case-cohort studies that use extensive biological sampling, particularly focusing on early disease and responses to medications, are required to establish successful biomarker discovery and validation programmes.

Profiling and Bioinformatics Analysis of Differentially Expressed circRNAs in Spinal Ligament Tissues of Patients with Ankylosing Spondylitis

Recent studies have reported that circular RNAs (circRNAs) play a crucial regulatory role in a variety of human diseases. However, the roles of circRNAs in ankylosing spondylitis (AS) remain unclear. In this study, we conducted circRNA expression profiling of the spinal ligament tissues of patients with AS by RNA sequencing (RNA-seq) and analyzed the potential functions of differentially expressed circRNA by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses to investigate the potential mechanisms associated with AS. The results showed that a total of 1,172 circRNAs were detected in the spinal ligament tissue samples, of which 123 circRNAs were significantly differentially expressed by a fold change ≥ 1.5 and p value < 0.05. Among these, 57 circRNAs were upregulated, and 66 were downregulated. GO and KEGG analyses demonstrated that the differentially expressed circRNAs were mainly involved in the regulation of biological processes of peptidyl-serine phosphorylation and human immune system that may be related to AS. In addition, the circRNA/miRNA interaction networks were established to predict the potential roles of differentially expressed circRNAs by bioinformatics analysis. Taken together, these results revealed the expression profiles of circRNAs and the potential functions of the differentially expressed circRNAs in the spinal ligament tissue of patients with AS, which may provide new clues for understanding the mechanisms associated with AS, and proceed to identify novel potential molecular targets for the diagnoses and treatment of AS.

Down-regulated miR-495 can target programmed cell death 10 in ankylosing spondylitis

Background

MicroRNAs (miRNAs) play crucial roles in regulating eukaryotic gene expression. Recent studies indicated that aberrantly expressed miRNAs are involved in the pathogenesis of ankylosing spondylitis (AS). Indeed, hsa-miR-495-3p (miR-495) has been reported as an anti-oncogene in different cancers. However, the role of miR-495 in AS is still unknown.

Methods

In this study, quantitative real-time polymerase chain reaction (PCR) was used to detect the expression of miR-495 in the peripheral blood mononuclear cells (PBMCs), whole blood, and serum of patients with AS. Bisulfite-specific PCR sequencing and methylated DNA immunoprecipitation were used to detect the methylation in the promoter region of miR-495. To determine the influence of miR-495 expression on the target gene, programmed cell death 10 (PDCD10), dual luciferase reporter assays together with an adenoviral vector containing the miR-495 locus were used. Receiver operating characteristic (ROC) curves were used to evaluate the efficacy of miR-495 as a diagnostic biomarker of AS. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes pathway analysis, and western blotting were used to explore the potential role of miR-495 in AS pathogenesis and the mechanism by which it facilitates AS pathogenesis.

Results

miR-495 is down-regulated and the promoter region of miR-495 is highly methylated in AS. The expression of miR-495 is negatively associated with PDCD10 expression in both patients with AS and healthy controls. Further experiments showed that PDCD10 can be targeted by miR-495. The ROC curves of miR-495 suggested that it is a very specific and sensitive biomarker for AS diagnosis. Bioinformatics analysis and signal pathway studies indicated that miR-495 can down-regulate β-catenin and transforming growth factor-β1.

Conclusions

Our studies indicated that down-regulation of miR-495 can be used as a potential molecular marker for the diagnosis and treatment of AS, thus providing new insights into the role of miRNAs in AS pathology.

Aberrant expression of microRNAs in peripheral blood mononuclear cells as candidate biomarkers in patients with axial spondyloarthritis

OBJECTIVES

Axial spondyloarthritis (axSpA) is a chronic inflammatory arthritis involving the axial skeleton. Recent evidence suggests that microRNAs (miRNAs) play a critical role in ankylosing spondylitis (AS). In this study, we aimed to investigate whether miR-17-5p, miR-27a, miR-29a and miR-126-3p can be verified as potential biomarkers of axSpA.

METHODS

Peripheral blood mononuclear cell (PBMC) miRNA expression was evaluated by quantitative real-time polymerase chain reaction among 43 patients with AS, 26 patients with non-radiographic axSpA (nr-axSpA) and 39 healthy controls. Detailed clinical histories were recorded and the correlation of miRNAs and clinical features were analyzed.

RESULTS

When compared to controls, both patients with AS and nr-axSpA had significantly higher expression levels of miR-17-5p, miR-27a, miR-29a and miR-126-3p. MiR-27a was negatively correlated with Ankylosing Spondylitis Disease Activity Score as well as C-reactive protein in patients with nr-axSpA (r = -0.51, P < 0.01 and r = -0.42, P = 0.034 respectively). No other clinical features were found to correlate with the four miRNAs in patients with AS. Mir-29a showed highest area under the curve with 0.952 and these four miRNAs may be potential biomarkers in patients with axSpA.

CONCLUSIONS

We reported elevated miR-17-5p, miR-27a, miR-29a and miR-126-3p expression in PBMCs of patients with axSpA, and the expression of these four miRNAs might be used as useful diagnostic markers in axSpA.

Plasma let-7i, miR-16, and miR-221 levels as candidate biomarkers for the assessment of ankylosing spondylitis in Mexican patients naïve to anti-TNF therapy

Novel biomarkers are needed for the diagnosis and clinical assessment of ankylosing spondylitis (AS). Our objective was to investigate plasma microRNAs differentially expressed between AS patients and controls and to evaluate their potential as biomarkers in Mexican subjects. A cross-sectional study including 15 AS patients naïve to anti-TNF therapy and 13 controls was performed. Disease activity, physical function, and global well-being were evaluated by the AS Disease Activity Score (ASDAS-CRP), the Bath AS Disease Activity Index (BASDAI), the Bath AS Functional Index (BASFI), and the AS Quality of Life Questionnaire (ASQoL), respectively. Total RNA was isolated from plasma of participants and relative expression of let-7i, miR-16, and miR-221 was evaluated. Serum levels of C-reactive protein (CRP), matrix metalloproteinase-1 (MMP-1), MMP-9, and intercellular adhesion molecule-1 (ICAM-1) were also measured. Expression of let-7i was higher in patients than in controls (1.8, 0.9 to 3.4 versus 0.6, 0.4 to 1.2; P = 0.033) with an AUC/ROC of 0.74 (0.54 to 0.93; P = 0.032). Levels of miR-16 and miR-221 were unable to discriminate between patients and controls. Notably, plasma miR-16 levels were inversely correlated with the ASDAS-CRP score (rho - 64, - 0.87 to - 0.18; P = 0.011), the BASFI score (rho - 0.78, - 0.93 to - 0.43; P = 0.001), and serum MMP-1 levels (rho - 0.59, - 0.85 to - 0.09; P = 0.022). No other associations were found. Plasma let-7i levels may serve as a biomarker for the diagnosis of AS in Mexican individuals. Additionally, plasma miR-16 levels are associated with disease activity and physical functionality in patients naïve to anti-TNF therapy.