Expression Profile and Potential Function of Circular RNAs in Peripheral Blood Mononuclear Cells in Male Patients With Primary Gout

Circular RNAs (circRNAs) are non-coding RNAs (ncRNAs) with a single-stranded covalently closed-loop structure, and their abnormal expression may participate in the pathogenesis of various human diseases. Currently, knowledge of circRNAs in gout is limited. In this case-control study, human circRNA microarrays were used to identify differentially expressed circRNAs in peripheral blood mononuclear cells (PBMCs) from patients with primary gout (n = 5) and healthy controls (HC; n = 3). Bioinformatics methods were used to analyze significantly different circRNAs (fold change >1.5, p < 0.05). In addition, four significantly differentially expressed circRNAs were selected for quantitative real-time polymerase chain reaction to detect expression levels in 90 gout patients and 60 HC. Subsequently, circRNA-miRNA-mRNA network was established to predict the function of circRNAs of interest. Microarray analysis indicated that 238 circRNAs were upregulated and 41 circRNAs were down-regulated in the gout group (fold change >1.5, p < 0.05). Bioinformatics analysis showed that differentially expressed circRNAs were involved in the pathogenesis of gout via various pathways. Moreover, the expression levels of hsa_circRNA_103657 and hsa_circRNA_000241 were significantly higher in the gout group than those in the HC group, and both correlated significantly with lipid metabolism parameters. Furthermore, the area under the curve of hsa_circRNA_103657 was 0.801 (95% confidence interval (CI): 0.730–0.871; p < 0.001). Our results provide novel insights into the pathogenesis of primary gout. Differentially expressed circRNAs were identified in the PBMCs of gout patients, and these differential circRNAs may play important roles in the development and progression of gout.

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 Chinese Han population to primary gout. Method：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. Method: 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. Result: 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.

Circulating microRNA alternations in primary hyperuricemia and gout

Objectives MicroRNAs (miRNAs) are short single-stranded RNAs that play a role in the post-transcriptional regulation of gene expression. Their deregulation can be associated with various diseases, such as cancer, neurodegenerative, and immune-related diseases. The aim of our study was to compare miRNA levels in plasma that could potentially influence the progression of hyperuricemia to gout, since the mechanism of progression is still unclear. Methods Total RNA, including miRNA, was isolated from the plasma of 45 patients with asymptomatic hyperuricemia, 131 patients with primary gout (including 16 patients having a gout attack), and 130 normouricemic controls. The expression of 18 selected miRNAs (cel-miR-39 and cel-miR-54 as spike-in controls, hsa-miR-16-5p and hsa-miR-25-3p as endogenous controls, hsa-miR-17-5p, hsa-miR-18a-5p, hsa-miR-30a-3p, hsa-miR-30c-5p, hsa-miR-126-3p, hsa-miR-133a-3p, hsa-miR-142-3p, hsa-miR-143-3p, hsa-miR-146a-5p, hsa-miR-155-5p, hsa-miR-222-3p, hsa-miR-223-3p, hsa-miR-488-3p and hsa-miR-920) was measured using qPCR. Results We found that hsa-miR-17-5p, hsa-miR-18a-5p, hsa-miR-30c-5p, hsa-miR-142-3p, and hsa-miR-223-3p were significantly upregulated (p < 0.001) in the plasma of hyperuricemia and gout patients compared to normouricemic individuals. As part of the follow-up of our previous study, we found a negative correlation between hsa-miR-17-5p, hsa-miR-30c-5p, hsa-miR-126-3p, hsa-miR-142-3p, and hsa-miR-223-3p with plasma levels of chemokine MCP-1. Additionally, we found a positive correlation between CRP and plasma levels of hsa-miR-17-5p, hsa-miR-18a-5p, hsa-miR-30c-5p, hsa-miR-126-3p, hsa-miR-142-3p, hsa-miR-146a-5p, hsa-miR-155-5p, hsa-miR-222-3p, and hsa-miR-223-3p. Five of those miRNAs (hsa-miR-126-3p, hsa-miR-142-3p, hsa-miR-146a-5p, hsa-miR-155-5p, and hsa-miR-222-3p) also had a positive correlation with serum creatinine and therefore a negative correlation with eGFR. Conclusion Five miRNAs were significantly upregulated in the plasma of patients with hyperuricemia and gout (and those during a gout attack) compared to normouricemic controls. We also found a correlation between the plasma levels of several miRNA and plasma levels of MCP-1, CRP, serum creatinine, and eGFR.

POS1142 INTERLEUKIN-37: ASSOCIATIONS OF PLASMA LEVELS AND GENETIC VARIANTS IN GOUT

Background:IL-37, recently characterized IL-1 family member, has anti-inflammatory effects by suppression of IL-1ß and other proinflammatory cytokines. In this study we investigated the effects of genetics variants in IL-37 link with IL-37 plasma levels in a cohorts of patients with hyperuricemia/gout.Objectives:The aim of this study was to determine the association of IL-37 gene polymorphism and plasma IL-37 levels in patients with hyperuricemia and gout.Methods:The cohorts consisted of 50 control subjects, 50 subjects of primary hyperuricemia, 50 subjects of primary gout, 28 subjects of tophaceous gout and 19 subjects of acute gout flare. The analyzed cohorts were selected from a previously reported set of 250 hyperuricemia/gout patients and 132 normouricemic subjects (1) according to the descending level of serum urate. All coding regions and intron-exon boundaries of IL-37, exon 1-5, were amplified and sequenced directly. Comparisons of presence/absence of identified variants was performed using P-values binomial test. Levels of plasma IL-37 were measured using Enzyme-Linked ImmunoSorbent Assay. All tests were performed in accordance with standards set by the institutional ethics committees, which approved the project in Prague (no.6181/2015).Results:We identified 12 IL-37 genetic variants: five intron (rs28947188, rs2466448, rs3811045, rs3811048, rs2708944), and seven non-synonymous allelic variants (rs3811046, rs3811047, rs2708943, rs2723183, rs2723187, rs2708947, rs27231927). Minor allele frequency (MAF) of those variants in European population from ExAC databases were used for comparison. Our data showed that the rs28947188, rs3811045, rs3811046, rs3811047, rs2723187, rs2708947, and rs27231927 variants were under-represented in the Czech hyperuricemia, gout, and tophaceous gout cohort compared with the control cohort and general European population (P = 0.0082 – 0.0395).The levels of plasma IL-37 were significantly higher in patients with tophaceous gout compared to control subjects (P 0.0329) whereas no changes were observed in subjects with primary hyperuricemia, primary gout or acute gout flare compared to control subjects. However, IL-37 was elevated in cohorts of patients with gout, tophaceous gout and acute gout flare compared to primary hyperuricemia subjects (P 0.0198, 0.0005, 0.0099; respectively).Conclusion:Although further analyzes are needed to elucidate the role of IL-37 in the gout, our results show that genetic variants in anti-inflammatory cytokine IL-37 are probably implicated in the pathogenesis of gout.References:[1]Toyoda Y, et al. Functional characterization of clinically-relevant rare variants in ABCG2 identified in a gout and hyperuricemia cohort. Cells. 2019 Apr 18;8(4).Acknowledgements:This study was supported by the grant from the Czech Republic Ministry of Health RVO 00023728.Disclosure of Interests:None declared.

Effects of fenofibrate therapy on renal function in primary gout patients

Objective To investigate the incidence and potential risk factors for development of fenofibrate-associated nephrotoxicity in gout patients. Methods A total of 983 gout patients on fenofibrate treatment who visited the dedicated Gout Clinic at the Affiliated Hospital of Qingdao University between September 2016 and June 2020 were retrospectively enrolled from the electronic records system. Fenofibrate-associated nephrotoxicity was defined as an increase in serum creatinine (SCr) ≥0.3 mg/dl within 6 months of fenofibrate initiation. The change trend of SCr and uric acid levels during the treatment period were assessed by a generalised additive mixed model (GAMM). Multivariate analysis was performed for risk factors affecting elevated SCr. Results A total of 100 (10.2%) patients experienced an increase in SCr ≥0.3 mg/dl within 6 months after fenofibrate initiation. The median change of SCr in the whole cohort was 0.11 mg/dl [interquartile range (IQR) 0.03–0.20], whereas it was 0.36 (0.33–0.45) in the fenofibrate-associated nephrotoxicity group. In a multivariable regression model, chronic kidney disease (CKD) [odds ratio (OR) 2.39 (95% CI 1.48, 3.86)] and tophus [OR 2.29 (95% CI 1.39, 3.78)] were identified to be risk predictors, independent of measured covariates, of fenofibrate-associated nephrotoxicity. During the treatment period, although SCr temporarily increased, serum urate and triglyceride concentrations decreased using the interaction analysis of GAMM. Of those with fenofibrate withdrawal records, the SCr increase in 65% of patients was reversed after an average of 49 days off the drug. Conclusions This observational study implied that fenofibrate-associated nephrotoxicity occurs frequently in gout patients, especially in patients with tophi or CKD. The potential renal risks of fenofibrate usage in gout needs additional research.

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.

LncRNAs Landscape in the patients of primary gout by Microarray Analysis

To determine the differential profiles of long non-coding RNAs (lncRNAs) in Peripheral blood mononuclear cells (PBMCs) among acute gout (AG) patients, intercritical gout (IG) patients and healthy control subjects, and to explore the specific biomarkers for acute gout diagnosis and treatment in future. Human lncRNA microarrays were used to identify the differentially expressed lncRNAs and mRNAs in primary AG (n=3), IG (n=3) and healthy subjects (n=3). For comparison Bioinformatics analyses were performed to predict the roles of abberrantly expressed lncRNAs and mRNAs. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to validate the results in 32 AG, 32 IG patients and 32 healthy control subjects. A receiver operating characteristic (ROC) curve was constructed to evaluate the diagnostic value of the lncRNAs identified in gout. The microarray analysis identified 3421 and 1739 differentially expressed lncRNAs, 2240 and 1027 differentially expressed mRNAs in AG and IG (fold change>1.5, P<0.05; respectively), respectively. qRT-PCR results of 9 dysregulated genes were consistent with the microarray data. 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 AG group than those in the IG group or healthy subjects (P<0.01, respectively). Moreover, the areas under the ROC curve were 0.955 and 0.961 for TCONS_00004393 and ENST00000566457,respectively. Our results provide novel insight into the mechanisms of the primary gout, and reveal that TCONS_00004393 and ENST00000566457 might be as candidate diagnostic biomarkers and targets for the treatment of acute gout.

Do Serum Urate–associated Genetic Variants Influence Gout Risk in People Taking Diuretics? Analysis of the UK Biobank

ObjectiveThe aim of this study was to determine whether serum urate (SU)–associated genetic variants differ in their influence on gout risk in people taking a diuretic compared to those not taking a diuretic.MethodsThis research was conducted using the UK Biobank Resource (n = 359,876). Ten SU-associated single-nucleotide polymorphisms (SNP) were tested for their association with gout according to diuretic use. Gene-diuretic interactions for gout association were tested using a genetic risk score (GRS) and individual SNP by logistic regression adjusting for relevant confounders.ResultsAfter adjustment, use of a loop diuretic was positively associated with prevalent gout (OR 2.34, 95% CI 2.08–2.63), but thiazide diuretics were inversely associated with prevalent gout (OR 0.60, 95% CI 0.55–0.66). Compared with a lower GRS (< mean), a higher GRS (≥ mean) was positively associated with gout in those not taking diuretics (OR 2.63, 2.49–2.79), in those taking loop diuretics (OR 2.04, 95% CI 1.65–2.53), in those taking thiazide diuretics (OR 2.70, 2.26–3.23), and in those taking thiazide-like diuretics (OR 2.11, 95% CI 1.37–3.25). No nonadditive gene-diuretic interactions were observed.ConclusionIn people taking diuretics, SU-associated genetic variants contribute strongly to gout risk, with a similar effect to that observed in those not taking a diuretic. These findings suggest that the contribution of genetic variants is not restricted to people with “primary” gout, and that genetic variants can play an important role in gout susceptibility in the presence of other risk factors.