Advanced oxidation protein products induce inflammatory responses and invasive behaviour in fibroblast-like synoviocytes via the RAGE-NF-κB pathway.

AIMS: Rheumatoid arthritis (RA), which mainly results from fibroblast-like synoviocyte (FLS) dysfunction, is related to oxidative stress. Advanced oxidation protein products (AOPPs), which are proinflammatory mediators and a novel biomarker of oxidative stress, have been observed to accumulate significantly in the serum of RA patients. Here, we present the first investigation of the effects of AOPPs on RA-FLSs and the signalling pathway involved in AOPP-induced inflammatory responses and invasive behaviour. METHODS: We used different concentrations of AOPPs (50 to 200 µg/ml) to treat RA-FLSs. Cell migration and invasion and the expression levels of tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), matrix metalloproteinase-3 (MMP-3), and MMP-13 were investigated. Western blot and immunofluorescence were used to analyze nuclear factor-κB (NF-κB) activation. RESULTS: AOPPs promoted RA-FLS migration and invasion in vitro and significantly induced the messenger RNA (mRNA) and protein expression of TNF-α, IL-6, MMP-3, and MMP-13 in dose- and time-dependent manners. Moreover, AOPPs markedly activated the phosphorylation of nuclear factor-κB (NF-κB) p65 protein, which triggered inhibitory kappa B-alpha (IκBα) degradation, NF-κB p65 protein phosphorylation, and NF-κB p65 translocation into the nucleus. Furthermore, treatment with a neutralizing antibody specific to receptor for advanced glycation end products (RAGE) significantly suppressed aggressive behaviour and inflammation, decreased TNF-α, IL-6, MMP-3, and MMP-13 expression, and blocked AOPP-induced NF-κB pathway activation. CONCLUSION: The results indicate that AOPPs can enhance aggressive behaviour and the inflammatory response in RA-FLSs via the RAGE-NF-κB pathway. These results present AOPPs as a new class of potentially important mediators of progressive disease in RA patients. Cite this article: Bone Joint Res 2021;10(4):259-268.

Circ_0088194 Promotes the Invasion and Migration of Rheumatoid Arthritis Fibroblast-Like Synoviocytes via the miR-766-3p/MMP2 Axis.

Dysregulation of circular RNAs (circRNAs) is involved in various human diseases. Fibroblast-like synoviocytes (FLSs), which form the lining of the joint, are epigenetically imprinted with an aggressive phenotype and contribute to joint destruction in rheumatoid arthritis (RA). In the present study, we identified a novel circRNA, Circ_0088194, which was upregulated in RA fibroblast-like synoviocytes (RA-FLSs) and correlated with the disease activity score in 28 joints. Overexpression of Circ_0088194 promoted RA-FLS migration and invasion, while inhibition of Circ_0088194 had the opposite effect. Mechanistically, Circ_0088194 acted as a miR-766-3p sponge to relieve the repressive effect of miR-766-3p on its target, MMP2 (encoding matrix metalloproteinase 2), thereby promoting migration and invasion. The expression level of Circ_0088194 was inversely correlated with that of miR-766-3p in RA-FLSs. Importantly, overexpression of miR-766-3p partially blocked the migration and invasion induced by Circ_0088194 overexpression. Collectively, this study identified a novel circRNA Circ_0088194 that promotes RA-FLS invasion and migration via the miR-766-3p/MMP2 axis. Circ_0088194 might represent a novel therapeutic target to prevent and treat RA.

Hsa_circ_0088036 promotes the proliferation and migration of fibroblast-like synoviocytes by sponging miR-140-3p and upregulating SIRT 1 expression in rheumatoid arthritis.

Circular RNAs (circRNAs) have been demonstrated to play crucial roles in the development and progression of various types of cancers by serving as microRNA sponges to regulate the expression of target genes. Although in-depth studies of circRNAs have been conducted, their functional and pathological significance in autoimmune diseases, including rheumatoid arthritis (RA), remains unclear. Our previous study verified that hsa_circ_0088036 (circ0088036) is significantly elevated in peripheral blood mononuclear cells from patients with RA. The present study aimed to explore the roles of circ0088036 in the pathogenesis of RA. The circ0088036/miR-140-3p/silent information regulator 1 (SIRT 1) axis was predicted by bioinformatics tools. Circ0088036 was found to be aberrantly upregulated in fibroblast-like synoviocytes (FLSs) in RA compared with FLSs in osteoarthritis (OA). Functionally, upregulated circ0088036 promoted the proliferation and migration of RA-FLSs. Mechanistically, circ0088036 acted as a miR-140-3p sponge to upregulate SIRT 1 expression, subsequently promoting RA progression. In conclusion, this study revealed that circ0088036 may play an essential role in promoting synovial pathogenesis via the circ0088036/miR-140-3p/SIRT 1 axis in RA, providing new insight into circRNAs during RA progression.

Transforming growth factor ß1 promotes fibroblast-like synoviocytes migration and invasion via TGF-ß1/Smad signaling in rheumatoid arthritis.

Migration and invasion are important characteristics of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs), which are involved in joint damage and contribute to rheumatoid arthritis (RA) pathology. However, the underlying mechanisms remain unclear. Because epithelial-mesenchymal transition (EMT) is a key mechanism related to migration and invasion in cancer cells, we investigated the relationship between EMT and RA-FLSs and explored whether the transforming growth factor ß1 (TGF-ß1)/Smad signaling pathway is involved. In vivo, fibroblast-like synoviocytes (FLSs) were isolated from the synovium of RA or osteoarthritis (OA) patients and cultured for 4-8 passages. EMT markers were detected by immunofluorescence and Western blotting. RA-FLSs were treated with TGF-ß1 or Smad2/3 small interfering RNA (siRNA), EMT markers were detected, and migration and invasion were assessed by Transwell assays. EMT markers could be detected in FLSs; when compared with osteoarthritis fibroblast-like synoviocytes (OA-FLSs), E-cadherin and vimentin decreased, while N-cadherin and α-smooth muscle actin (α-SMA) increased in RA-FLSs. Furthermore, TGF-ß1 enhanced migration and invasion by inducing EMT via activating Smad2/3 in RA-FLSs. Phosphorylation of Smad2/3 was accompanied by degradation of Smad3. Silencing Smad2/3 blocked EMT and inhibited the migration and invasion induced by TGF-ß1. Matrix metalloproteinase 9 (MMP9) and vimentin were not affected when cells were treated with TGF-ß1 or Smad2/3 siRNA. The TGF-ß1/Smad signaling pathway is involved in EMT and contributes to migration and invasion in RA-FLSs. Interestingly, vimentin decreased in RA-FLSs, but there is no correlation between vimentin and TGF-ß1/Smad signaling pathway. Thus, further research on vimentin should be conducted.

MicroRNA­198 contributes to lupus nephritis progression by inhibition of phosphatase and tensin homology deleted on chromosome ten expression.

A number of short noncoding microRNAs (miRs) have been demonstrated to be highly expressed in many kidney diseases such as renal cancer and lupus nephritis (LN); however, these results have not been extensively investigated. The aim of the present study was to investigate the expression and function of miR­198 in LN based on the previous studies. miR­198 expression level in systemic lupus erythematosus (SLE) patients was determined to determine its clinicopathological significance and effect on glomerular cell proliferation. It was demonstrated that higher expression of miR­198 was observed in patients with SLE, and was correlated with disease activity. Bioinformatics prediction and luciferase assays were used to demonstrate that miR­198 could directly bind to the phosphatase and tensin homology deleted on chromosome ten (PTEN) 3'­untranslated region. Furthermore, miR­198 overexpression reduced PTEN expression levels, while miR­198 silencing increased its expression at both the mRNA and protein level. Furthermore, there was a negative association between miR­198 and PTEN in the patients with active SLE. Thus, miR­198 may promote proliferation and contribute to SLE progression by targeting PTEN.

Microarray Expression Profile of Circular RNAs in Peripheral Blood Mononuclear Cells from Rheumatoid Arthritis Patients.

BACKGROUND/AIMS: Circular RNAs (circRNAs) compose a large class of RNAs that can be used as biomarkers in clinical blood samples. This study aimed to determine the expression of circRNAs in peripheral blood mononuclear cells (PBMCs) from rheumatoid arthritis (RA) patients to identify novel biomarkers for RA screening. METHODS: We started with a microarray screening of circRNA changes in PBMCs from 5 RA patients and 5 healthy controls. We then confirmed the selected circRNA changes in PBMCs from 30 RA patients and 25 age- and sex-matched controls using the real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Spearman correlation test was performed to assess the correlation of circRNAs and clinical variables. Receiver operating characteristic (ROC) curve was calculated to evaluate the diagnostic value. RESULTS: We identified and verified five circRNAs (092516, 003524, 103047, 104871, 101873) that were significantly elevated in PBMCs from RA patients. Among these RA patients, we detected no significant correlation between the five circRNAs and the disease severity, including disease activity score (DAS28), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and health assessment questionnaire (HAQ). Yet, ROC curve analysis suggested that circRNA_104871 has significant value of RA diagnosis (AUC=0.833, P<0.001), followed by circRNA_003524 (AUC = 0.683, P = 0.020), circRNA_101873 (AUC = 0.676, P = 0.026), and circRNA_103047 (AUC = 0.671, P = 0.030). CONCLUSIONS: This study suggests that increased expression of circRNAs circRNA_104871, circRNA_003524, circRNA_101873 and circRNA_103047 in PBMC from RA patients may serve as potential biomarkers for RA patient diagnosis.

[Simultaneous qualitative and quantitative determination of seven anticoagulant rodenticides in whole blood and urine samples using on-line solid phase extraction with liquid chromatography-linear ion trap mass spectrometry].

A new and sensitive analytical method has been developed for the simultaneous determination of seven anticoagulant rodenticides in whole blood and urine samples by liquid chromatography-linear ion trap mass spectrometry (LC-LIT/MS) with on-line solid phase extraction (on-line SPE). The samples were treated with acetonitrile, followed by dilution, centrifugation, and filtration. The resulting solution was injected into the LC system directly and processed by on-line SPE column for enrichment and purification. Separation was performed on a C18 column with mixed mobile phases of methanol and 0.02 mol/L ammonium acetate aqueous solution for gradient elution. The analytes were detected by the mass spectrometer with electrospray ionization (ESI) in negative mode. MS2 full scan signals of the target parent ions within the locked retention time window were recorded. Self-built database searching was performed for qualitative confirmation, and MS2 fragment ions with high sensitivity and specificity were selected for quantification. Simultaneous qualitative and quantitative analyses of the seven rodenticides were achieved in this way. Good linearities were obtained within the investigated mass concentration ranges of the seven rodenticides, with r2 ≥ 0.9958 in blood and r2 ≥ 0.9946 in urine. The LODs varied from 0.02 ng/mL to 1.00 ng/mL, and the LOQs varied from 0.10 ng/mL to 4.00 ng/mL. The recoveries at three spiked levels in blood and urine samples ranged from 81.0% to 113.9%, with RSDs of 0.1%-6.2% (n = 6). The developed method is simple, sensitive, and can be used for the rapid detection and accurate quantification of the seven anticoagulant rodenticides in whole blood and urine samples.

Association between job strain and risk of incident stroke: A meta-analysis.

OBJECTIVE: Prospective cohort studies regarding job strain and the risk of stroke are controversial. This meta-analysis aimed to evaluate the association between job strain and the risk of stroke. METHODS: The PubMed, Embase, and PsycINFO databases were searched for prospective cohort studies with data on job strain and the risk of stroke. Studies were included if they reported adjusted relative risks (RRs) with 95% confidence intervals (CIs) of stroke from job strain. Subgroup analyses were conducted according to sex and stroke type. RESULTS: Six prospective cohort studies comprising 138,782 participants were included. High strain jobs were associated with increased risk of stroke (RR 1.22, 95% CI 1.01-1.47) compared with low strain jobs. The result was more pronounced for ischemic stroke (RR 1.58, 95% CI 1.12-2.23). The risk of stroke was significant in women (RR 1.33, 95% CI 1.04-1.69) and nonsignificant in men (RR 1.26, 95% CI 0.69-2.27), but the difference in RRs in sex subgroups was not significant. Neither active (RR 1.07, 95% CI 0.90-1.28) nor passive (RR 1.01, 95% CI 0.86-1.18) job characteristics were associated with an increased risk of stroke compared with low strain jobs. CONCLUSIONS: Exposure to high strain jobs was associated with an increased risk of stroke, especially in women. Further studies are needed to confirm whether interventions to reduce work stress decrease the risk of stroke.

Prehypertension and the risk of coronary heart disease in Asian and Western populations: a meta-analysis.

BACKGROUND: The results of studies on the association between prehypertension (blood pressure 120 to 139/80 to 89 mm Hg) and coronary heart disease (CHD) remain controversial. Furthermore, it is unclear whether prehypertension affects the risk of CHD in Asian and Western populations differently. This meta-analysis evaluated the risk of CHD associated with prehypertension and its different subgroups. METHODS AND RESULTS: The PubMed and Embase databases were searched for prospective cohort studies with data on prehypertension and the risk of CHD. Studies were included if they reported multivariate-adjusted relative risks (RRs) with 95% CIs of CHD from prehypertension. A total of 591 664 participants from 17 prospective cohort studies were included. Prehypertension increased the risk of CHD (RR 1.43, 95% CI 1.26 to 1.63, P<0.001) compared with optimal blood pressure (<120/80 mm Hg). The risk of CHD was higher in Western than in Asian participants (Western: RR 1.70, 95% CI 1.49 to 1.94; Asian: RR 1.25, 95% CI 1.12 to 1.38; ratio of RRs 1.36, 95% CI 1.15 to 1.61). The population-attributable risk indicated that 8.4% of CHD in Asian participants was attributed to prehypertension, whereas this proportion was 24.1% in Western participants. CONCLUSIONS: Prehypertension, even at the low range, is associated with an increased risk of CHD. This risk is more pronounced in Western than in Asian populations. These results supported the heterogeneity of target-organ damage caused by prehypertension and hypertension among different ethnicities and underscore the importance of prevention of CHD in Western patients with prehypertension.

Prevalence and risk factors associated with prehypertension in Shunde District, southern China.

OBJECTIVE: To explore the prevalence and combined cardiovascular risk factors of prehypertension in southern China. DESIGN: A retrospective study; the logistic regression model was used to find the risk factors of prehypertension. SETTING: The study was conducted in Shunde District, southern China, using the community-based health check-up information. PARTICIPANTS: Participants aged ≥35 years with complete health check-up information data between January 2011 and December 2013 were enrolled and divided into hypertension, prehypertension and optimal blood pressure (BP) groups. Prehypertension was further divided into low-range (BP 120-129/80-84 mm Hg) and high-range (BP 130-139/85-89 mm Hg) subgroups. OUTCOME MEASURES: The prevalence of prehypertension and the combined cardiovascular risk factors within the prehypertensive subgroups. RESULTS: Of the 5362 initially reviewed cases (aged ≥35 years), 651 were excluded because of missing data. The proportions of optimal BP, prehypertension and hypertension were 39.1%, 38.6% and 22.3%, respectively. The average age, proportion of male sex, overweight, impaired fasting glucose (IFG), dyslipidaemia and hyperuricaemia were significantly higher in the prehypertension group than in the optimal BP group (all p <0.05). Compared with low-range prehypertension, the proportions of overweight, dyslipidaemia and IFG were higher in the high-range prehypertension group (all p<0.05). Multivariate logistic regression analysis showed that overweight (OR=2.84, 95% CI 1.55 to 5.20), male sex (OR=2.19, 95% CI 1.39 to 3.45), age (per 10 years, OR=1.21, 95% CI 1.02 to 1.44, p=0.03) and hyperuricaemia (OR=1.70, 95% CI 1.14 to 2.54) were independent risk factors of prehypertension. CONCLUSIONS: Prehypertension is highly prevalent in southern China. Prehypertensive individuals presented with many other cardiovascular risk factors. There was heterogeneity of combined risk factors within the prehypertensive subgroups.

Increased serum 2-oxoglutarate associated with high myocardial energy expenditure and poor prognosis in chronic heart failure patients.

Myocardial energy expenditure (MEE) and 2-oxoglutarate are elevated in chronic heart failure (CHF) patients compared with healthy controls. To explore whether 2-oxoglutarate could reflect the levels of MEE and predict the prognosis of CHF, 219 CHF patients and 66 healthy controls were enrolled. 2-Oxoglutarate was assayed with Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (LC/MS/MS). CHF patients were divided into 4 groups according to interquartile range of MEE and followed for death or recurrent hospital admission due to CHF for the mean follow-up time 6.64±0.16months. 2-Oxoglutarate was increased in CHF patients compared with controls (P<0.01) and correlated with estimated glomerular filtration rate (r=0.142, P=0.036), age (r=-0.269, P<0.01) and MEE levels (r=0.307, P<0.01) in a multiple linear correlation analysis in CHF patients. Furthermore, 2-oxoglutarate (OR=3.470, 95% CI=1.557 to 7.730, P=0.002), N-terminal pro-B-type natriuretic peptide (OR=4.013, 95% CI=1.553 to 10.365, P=0.004), age (OR=1.611, 95% CI=1.136 to 2.283, P=0.007) and left ventricular ejection fraction (OR=7.272, 95% CI=3.110 to 17.000, P<0.001) were independently associated with MEE on multiple logistic regression analysis. Kaplan-Meier event curves showed that high 2-oxoglutarate levels were associated with adverse outcomes (Log Rank, Chi(2)=4.026, P=0.045). This study showed that serum 2-oxoglutarate is associated with MEE levels, which can be used as potential biomarkers for MEE, and it can reflect the clinical severity and short-term outcome of CHF.