Circular RNAs in peripheral blood mononuclear cells from ankylosing spondylitis.

BACKGROUND: Circular RNA (circRNA) is a type of closed circular noncoding RNA (ncRNA), mostly formed by back-splicing or alternative splicing of pre-messenger RNA (mRNA). The aim of this study was to explore the expression profile of circRNA in peripheral blood mononuclear cells (PBMCs) of patients with ankylosing spondylitis (AS) and discover potential molecular markers of AS. METHODS: The circRNA microarray technology was used to detect the expression of circRNAs in the peripheral blood of 6 patients with AS and 6 healthy controls (HC). To screen the differentially expressed circRNAs by fold change (FC) and P value, these differentially expressed circRNAs were analyzed by bioinformatics. In 60 cases of AS and 30 cases of HC, 4 circRNAs were subjected to real-time fluorescence quantitative polymerase chain reaction (RT-qPCR), and their correlation with various clinical indicators was analyzed. Finally, the receiver operating characteristic (ROC) curve was used to analyze their potential as AS diagnostic markers. RESULTS: The microarray results showed that there were 1369 significantly differently expressed (P < 0.05, FC > 1.5) circRNAs between the AS and HC groups (675 upregulated and 694 downregulated). The results of bioinformatics analysis suggested that they were mainly involved in "enzyme binding," "adenosine ribonucleotide binding," "MAPK signaling pathway", etc. The RT-qPCR results showed that the expressions of hsa_circRNA_001544 (U = 486.5, P < 0.05) and hsa_circRNA_102532 (U = 645, P < 0.05) were significantly different between the AS group and the HC group. The AS group was further divided into two subgroups: active AS (ASA) and stable AS (ASS). After analysis, it was found that compared with the HC group, hsa_circRNA_001544 was significantly increased in both ASA (U = 214, P < 0.05) and ASS groups (U = 273, P < 0.05), while hsa_circRNA_008961 (U = 250, P < 0.05) and hsa_circRNA_102532 (U = 295, P < 0.05) were only significantly increased in the ASA group. Furthermore, hsa_circRNA_012732 was significantly different between the ASA and ASS groups (U = 194, P < 0.05), and there was no statistical significance among the remaining groups. Correlation analysis results showed that hsa_circRNA_012732 was negatively correlated with Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), high-sensitivity C-reactive protein (hsCRP), and globulin (GLOB) and positively correlated with lymphocyte count (LY), mean corpusular volume, and albumin (ALB), and hsa_circRNA_008961 was negatively correlated with platelet (PLT) count. ROC curve analysis showed that hsa_circRNA_001544 (95% CI = 0.610-0.831, P < 0.05) and hsa_circRNA_102532 (95% CI = 0.521-0.762, P < 0.05) were statistically significant, and their area under curve (AUC) values were 0.720 and 0.642, respectively. CONCLUSIONS: There are differentially expressed circRNAs in PBMCs of AS patients, and they may be involved in the occurrence and development of AS. Among these differentially expressed circRNAs, hsa_circRNA_012732 has the potential to become an indicator of disease activity, and hsa_circRNA_001544 has the potential to become a molecular marker for AS diagnosis.

No Association of MicroRNA-146a rs2910164 Polymorphism and Risk of Primary Gout Development in Chinese Han Populations: A Case-control Study.

BACKGROUND: Previous studies demonstrated that MicroRNA-146a (miR-146a) plays an important role in the regulation of autoinflammatory diseases including primary gout. The G/C polymorphism (rs2910164) in the precursor sequence of miR-146a caused its stem region to change from G: U to C: U,which can contribute to the susceptibility of human diseases. However, no genetic relevance studies of miR-146a gene polymorphisms to gout have been reported by now. OBJECTIVE: The purpose of this study was to analyze the association between the miR-146a rs2910164 genetic polymorphism and the susceptibility of the Chinese Han population to primary gout. METHODS: 1130 Chinese Han participants (including 606 primary gout patients and 524 gender and age-matched healthy control subjects) were recruited and the 5'exonuclease TaqMan® technology was used to perform miR-146a rs2910164 genotyping. RESULTS: After statistical analysis, no significant differences were observed between gout patients and healthy controls in genotype and allele frequency. CONCLUSION: Our results indicate that there is no evidence for the involvement of the miR-146a rs2910164 polymorphisms in susceptibility to primary gout in the Chinese Han population.

MicroRNA-223 Suppresses IL-1ß and TNF-α Production in Gouty Inflammation by Targeting the NLRP3 Inflammasome.

Introduction: MicroRNA-223 (MiR-223) serves as an important regulator of inflammatory and immune responses and is implicated in several auto-inflammatory disorders. Here, we measured miR-223 expression in acute and intercritical gout patients, after which we used RAW264.7 macrophages transfected with a miR-223 mimic/inhibitor to determine the function of miR-223 in monosodium urate (MSU)-induced gouty inflammation. Methods and Results: MiR-223 was detected among 122 acute gout patients (AG), 118 intercritical gout patients (IG), and 125 healthy subjects (HC). RAW264.7 macrophages were cultured and treated with MSU. Over-expression or under-expression of miR-223 was inducted in RAW264.7 macrophages to investigate the function of miR-223. Real-time quantitative PCR, ELISA and western blotting were used to determine the expression levels of miR-223, cytokines and the NLRP3 inflammasome (NLRP3, ASC, and caspase-1). MiR-223 expression was significantly decreased in the AG group in comparison with the IG and HC groups (p < 0.001, respectively). Up-regulated expression of miR-223 was observed after acute gout remission in comparison with that observed during gout flares in 30 paired cases (p < 0.001). The abundance of the NLRP3 inflammasome and cytokines was significantly increased after RAW264.7 macrophages were treated with MSU (p < 0.01, respectively), while that of miR-223 was significantly reduced (p < 0.01). Up-regulation of miR-223 decreased the concentrations of IL-1ß and TNF-α, as well as the NLRP3 inflammasome expression (p < 0.01, respectively), while IL-37 and TGF-ß1 levels were unchanged (p > 0.05, respectively). Under-expression of miR-223 increased the concentrations of IL-1ß and TNF-α, as well as NLRP3 inflammasome expression (p < 0.01, respectively), while IL-37 and TGF-ß1 levels were not influenced (p > 0.05, respectively). Conclusion: These findings suggest that miR-223 provides negative feedback regulation of the development of gouty inflammation by suppressing production of IL-1ß and TNF-α, but not by regulating IL-37 and TGF-ß1. Moreover, miR-223 regulates cytokine production by targeting the NLRP3 inflammasome.

LncRNAs Landscape in the patients of primary gout by microarray analysis.

To determine the expression profile and clinical significance of long non-coding RNAs (lncRNAs) in peripheral blood mononuclear cells (PBMCs) of patients with primary gout and healthy control subjects. Human lncRNA microarrays were used to identify the differentially expressed lncRNAs and mRNAs in primary gout patients (n = 6) and healthy control subjects (n = 6). Bioinformatics analyses were performed to predict the roles of differently expressed lncRNAs and mRNAs. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expression levels of 8 lnRNAs in 64 primary gout patients and 32 healthy control subjects. Spearman's correlation was used to analyze the correlation between these eight lncRNAs and the laboratory values of gout patients. A receiver operating characteristic (ROC) curve was constructed to evaluate the diagnostic value of the lncRNAs identified in gout. The microarray analysis identified 1479 differentially expressed lncRNAs (879 more highly expressed and 600 more lowly expressed), 862 differentially expressed mRNAs (390 more highly expressed and 472 more lowly expressed) in primary gout (fold change > 2, P < 0.05), respectively. The bioinformatic analysis indicated that the differentially expressed lncRNAs regulated the abnormally expressed mRNAs, which were involved in the pathogenesis of gout through several different pathways. The expression levels of TCONS_00004393 and ENST00000566457 were significantly increased in the acute gout flare group than those in the intercritical gout group or healthy subjects (P<0.01). Moreover, inflammation indicators were positive correlated with TCONS_00004393 and ENST00000566457 expression levels. The areas under the ROC curve of ENST00000566457 and NR-026756 were 0.868 and 0.948, respectively. Our results provide novel insight into the mechanisms of primary gout, and reveal that TCONS_00004393 and ENST00000566457 might be as candidate targets for the treatment of gout flare; ENST00000566457 and NR-026756 could effectively discriminate between the gout and the healthy control groups.