Low Soluble Receptor for Advanced Glycation End Products Precedes and Predicts Cardiometabolic Events in Women With Rheumatoid Arthritis

Background: Cardiovascular disease (CVD) causes premature mortality in rheumatoid arthritis (RA). Levels of soluble (s)RAGE change with aging, hypertension and hypercholesterolemia. We assessed whether sRAGE was associated with increased risk of CVD in RA patients.

Methods: Serum sRAGE was measured in 184 female RA patients and analyzed with respect to CVD risk estimated by the Framingham algorithm (eCVR), metabolic profile and inflammation. Levels of sRAGE in 13 patients with known cardio-metabolic morbidity defined the cut-off for low sRAGE. Prospective 5-year follow-up of new CV and metabolic events was completed.

Results: Low sRAGE was significantly associated with previous history and with new imminent cardiometabolic events in the prospective follow-up of RA patients. In both cases, low sRAGE reflected higher estimation of CVR in those patients. Low sRAGE was attributed to adverse metabolic parameters including high fasting plasma glucose and body fat content rather than inflammation. The association of sRAGE and poor metabolic profile was prominent in patients younger than 50 years.

Conclusions: This study points at low sRAGE as a marker of metabolic failure developed during chronic inflammation. It highlights the importance for monitoring metabolic health in female RA patients for timely prevention of CVD.

Trial registration:ClinicalTrials.gov with ID NCT03449589. Registered 28, February 2018.

Nicotine Changes the microRNA Profile to Regulate the FOXO Memory Program of CD8+ T Cells in Rheumatoid Arthritis

Objective: Smoking suppresses PD-1 expression in patients with rheumatoid arthritis (RA). In this study, we assess if smoking changed the epigenetic control over CD8⁺ T cell memory formation through a microRNA (miR) dependent mechanism.

Methods: Phenotypes of CD8⁺ T cells from smokers and non-smokers, RA and healthy, were analyzed by flow cytometry. A microarray analysis was used to screen for differences in miR expression. Sorted CD8⁺ cells were in vitro stimulated with nicotine and analyzed for transcription of miRs and genes related to memory programming by qPCR.

Results: CD27⁺CD107a⁻CD8⁺ T cells, defining a naïve-memory population, had low expression of PD-1. Additionally, the CD27⁺ population was more frequent in smokers (p = 0.0089). Smokers were recognized by differential expression of eight miRs. Let-7c-5p, let-7d-5p and let-7e-5p, miR-92a-3p, miR-150-5p, and miR-181-5p were up regulated, while miR-3196 and miR-4723-5p were down regulated. These miRs were predicted to target proteins within the FOXO-signaling pathway involved in CD8⁺ memory programming. Furthermore, miR-92a-3p was differentially expressed in CD8⁺ cells with naïve-memory predominance. Nicotine exposure of CD8⁺ cells induced the expression of miR-150-5p and miR-181a-5p in the naïve-memory cells in vitro. Additionally, nicotine exposure inverted the ratio between mRNAs of proteins in the FOXO pathway and their targeting miRs.

Conclusions: Smokers have a high prevalence of CD8⁺ T cells with a naïve-memory phenotype. These cells express a miR profile that interacts with the memory programming conducted through the FOXO pathway.

Low serum IGF1 is associated with hypertension and predicts early cardiovascular events in women with rheumatoid arthritis

OBJECTIVES

Since low insulin-like growth factor (IGF) 1 is often linked to inflammation, we analyze whether serum levels of IGF1 are associated with cardiovascular disease (CVD) in rheumatoid arthritis (RA) in a longitudinal observational study.

METHODS

A CVD risk was estimated (eCVR) in 184 female RA patients (mean age 52 years) and in 132 female patients after ischemic stroke (mean age 56 years) with no rheumatic disease, using the Framingham algorithm. The median level of IGF1 divided the cohorts in IGF1^high and IGF1^low groups. A 5-year prospective follow-up for new CVD events was completed in all RA patients. The Mantel-Cox analysis and event-free survival curves were prepared. Unsupervised clustering of proteins within the IGF1 signaling pathway was employed to identify their association with eCVR.

RESULTS

Low IGF1 resulted in a higher eCVR in RA patients (7.2% and 3.3%, p = 0.0063) and in stroke (9.3% and 7.1%, p = 0.033). RA had higher rate for new CVD events at prospective follow-up (OR 4.96, p = 0.028). Hypertension was the major risk factor associated with low IGF1 in RA and stroke. In hypertension, IGF1 was no longer responsible for intracellular activation and lost its correlation to IRS1/2 adaptor proteins. The clustering analysis confirmed that combination of low IGF1 and IRS1/2 with high IL6, insulin, and glucose predisposed to high eCVR and emphasized the functional role of serum IGF1.

CONCLUSIONS

Low serum IGF1 precedes and predicts development of early CVD events in female RA patients. Hypertension and aberrant IGF1 receptor signaling are highlighted as the important contributors to IGF1-related CVD events.

Smoking Is Associated With Low Levels of Soluble PD-L1 in Rheumatoid Arthritis

Background

Smoking is a risk factor for developing rheumatoid arthritis (RA), but the mechanism remains uncertain. We previously demonstrated that smoking lowers the T cell activation threshold by limiting programmed death protein 1 (PD-1) expression.

Aim

To investigate how smoking influence the levels of soluble PD-1 ligand (sPD-L1).

Method

Serum levels of sPD-L1 were measured in 246 RA patients and in 168 healthy subjects. The analysis was done with respect to inflammation, smoking, treatments, and autoantibody status. The effect of therapeutic TNF-inhibiting antibodies (TNFi) on sPD-L1 was studied in 16 RA patients at their first infliximab infusion. The expression of Fcγ-receptor (FcγR) subclass IIB and IIIA was analyzed with quantitative polymerase chain reaction in peripheral blood mononuclear cells (PBMCs) from 12 RA patients and 15 healthy controls, and in healthy PBMC exposed to IgG containing antibodies to cyclic citrullinated peptides (aCCP).

Results

The negative association between smoking and sPD-L1 in RA patients was established by multiple logistic regression (OR = 0.52, p = 0.038). Other covariates in the regression model were serum levels of IL-1β representing inflammation (OR = 1.6, p = 0.0076) and aCCP positivity (OR = 1.9, p = 0.047). First infliximab infusion repressed sPD-L1 (p = 0.023) in patients, and low levels of sPD-L1 were found in patients with early RA treated with TNFi (p = 0.018). Treatment with TNFi was associated with higher sPD-L1 in patients with long disease duration (p = 0.041) and restored levels in smokers. In vitro exposure to aCCP+ IgG suppressed sPD-L1 (p = 0.036), but aCCP+ patients with long disease duration had higher sPD-L1 (p = 0.016). High ratio of the inhibitory FcγR subclass IIB over the stimulatory IIIA resulted in low sPD-L1 release (p = 0.029). Smoking was associated with a higher FcγR IIB/IIIA ratio (p = 0.00062) and lower levels of sPD-L1 (p = 0.013).

Conclusion

In RA, serum sPD-L1 was related to systemic inflammation and aCCP positivity. Smoking altered the expression of FcγRs and limited sPD-L1 in RA patients, permitting inappropriate T cell responses. Differential regulation of sPD-L1 during the early and late RA may indicate transposition from acute to chronic inflammation.

High Expression of STAT3 in Subcutaneous Adipose Tissue Associates with Cardiovascular Risk in Women with Rheumatoid Arthritis

Despite the predominance of female patients and uncommon obesity, rheumatoid arthritis (RA) is tightly connected to increased cardiovascular morbidity. The aim of this study was to investigate transcriptional activity in the subcutaneous white adipose tissue (WAT) with respect to this disproportionate cardiovascular risk (CVR) in RA. CVR was estimated in 182 female patients, using the modified Systematic Coronary Risk Evaluation scale, and identified 93 patients with increased CVR. The overall transcriptional activity in WAT was significantly higher in patients with CVR and was presented by higher serum levels of WAT products leptin, resistin and IL-6 (all, p < 0.001). CVR was associated with high WAT-specific transcription of the signal transducer and activator of transcription 3 (STAT3) and the nuclear factor NF-kappa-B p65 subunit (RELA), and with high transcription of serine-threonine kinase B (AKT1) in leukocytes. These findings suggest Interleukin 6 (IL-6) and leptin take part in WAT-specific activation of STAT3. The binary logistic regression analysis confirmed an independent association of CVR with IL-6 in serum, and with STAT3 in WAT. The study shows an association of CVR with transcriptional activity in WAT in female RA patients. It also emphasizes the importance of STAT3 regulatory circuits for WAT-related CVR in RA.

IGF-1R signalling contributes to IL-6 production and T cell dependent inflammation in rheumatoid arthritis

BACKGROUND

Signalling through insulin-like growth factor 1 receptor (IGF-1R) is essential for cell survival, but may turn pathogenic in uncontrolled tissue growth in tumours. In rheumatoid arthritis (RA), the IGF-1R signalling is activated and supports expansion of the inflamed synovia.

AIM

In the present study, we assess if disruption of IGF-1R signalling resolves arthritis.

MATERIAL AND METHODS

Clinical associations of IGF-1R expression in leukocytes of the peripheral blood were studied in 84 RA patients. Consequences of the IGF-1R signalling inhibition for arthritis were studied in mBSA immunised Balb/c mice treated with NT157 compound promoting degradation of insulin receptor substrates.

RESULTS

In RA patients, high expression of IGF-1R in leukocytes was associated with systemic inflammation as verified by higher expression of NF-kB, serum levels of IL6 and erythrocyte sedimentation rate, and higher pain perception. Additionally, phosphorylated IGF-1R and STAT3 enriched T cells infiltrate in RA synovia. Treatment with NT157 inhibited the phosphorylation of IGF-1R and STAT3 in synovia, and alleviated arthritis and joint damage in mice. It also reduced expression of IGF-1R and despaired ERK and Akt signalling in spleen T cells. This limited IL-6 production, changed RoRgt/FoxP3 balance and IL17 levels.

CONCLUSION

IGF-1R signalling contributes to T cell dependent inflammation in arthritis. Inhibition of IGF-1R on the level of insulin receptor substrates alleviates arthritis by restricting IL6-dependent formation of Th17 cells and may open for new treatment strategies in RA.

Smoking activates cytotoxic CD8+ T cells and causes survivin release in rheumatoid arthritis

CD8⁺ T cells have an emerging role in RA. Resent research indicates a causal relationship between the non-exhausted state of CD8⁺ T cells, defined by lost function of PD-1, and development of arthritis. We investigated how smoking contributes to the non-exhausted phenotype of CD8⁺ T cells and cause survivin release to serum. We compared serum survivin levels between smokers and non-smokers in 252 RA and 168 healthy subjects. Nicotine effects on CD8⁺ T cells were studied in peripheral blood of smoking women, bone marrow of nicotine treated mice and in sorted CD8 spleen cells in vitro using flow cytometry and quantitative PCR. Smoking increased the frequency of survivin release in serum of healthy women (OR 3.64, p = 0.025) and in RA patients (OR 1.98, p = 0.039). CD8⁺ T cells of smokers gained a non-exhausted PD-1 deficient phenotype. Expression of the cytotoxic marker CD107 correlated to survivin levels in serum. In the experimental setting, nicotine exposure led to an accumulation of non-exhausted PD-1^-IL-7R⁺ CD8⁺ T cells in the bone marrow that is abundant with survivin producing cells. The production of the cytolytic protein perforin in bone marrow correlated to serum survivin levels. In vitro stimulation of nicotinic receptors on murine CD8⁺ T cells induced repressive transcription factors T-bet and Blimp-1 in support of the non-exhausted phenotype. We conclude that nicotine contributes to autoimmunity by supporting the non-exhausted state of CD8⁺ T cells resulting in the release of survivin. This presents a new mechanism by which smoking may contribute to the pathogenesis of RA.