Splicing machinery is profoundly altered in systemic lupus erythematosus and antiphospholipid syndrome and directly linked to key clinical features

OBJECTIVES

To characterize the splicing machinery (SM) of leukocytes from primary antiphospholipid syndrome (APS), systemic lupus erythematosus (SLE) and antiphospholipid syndrome with lupus (APS + SLE) patients, and to assess its clinical involvement.

METHODS

Monocytes, lymphocytes and neutrophils from 80 patients (22 APS, 35 SLE and 23 APS + SLE) and 50 HD were purified, and 45 selected SM components were evaluated by qPCR-microfluidic array. Relationship with clinical features and underlying regulatory mechanisms were assessed.

RESULTS

APS, SLE and APS + SLE leukocytes displayed significant and specific alterations in SM-components (SMC), associated with clinical features [autoimmune profiles, disease activity, lupus nephritis (LN), and CV-risk markers]. A remarkable relationship among dysregulated SMC in monocytes and the presence of LN in SLE was highlighted, revealing a novel pathological mechanism, which was further explored. Immunohistology analysis of renal biopsies highlighted the pathological role of the myeloid compartment in LN. Transcriptomic analysis of monocytes from SLE-LN(+) vs SLE-LN(-) identified 271 genes differentially expressed, mainly involved in inflammation and IFN-signaling. Levels of IFN-related genes correlated with those of SMC in SLE-LN(+). These results were validated in two external SLE-LN(+) datasets of whole-blood and kidney biopsies. In vitro, SLE-LN(+)-serum promoted a concomitant dysregulation of both, the IFN signature and several SMC, further reversed by JAKinibs treatment. Interestingly, IFNs, key inflammatory cytokines in SLE pathology, also altered SMC. Lastly, the over/down-expression of selected SMC in SLE-monocytes reduced the release of inflammatory cytokines and their adhesion capacity.

CONCLUSION

Overall, we have identified, for the first time, a specific alteration of SMC in leukocytes from APS, SLE and APS + SLE patients that would be responsible for the development of distinctive clinical profiles.

Complement component 3 as biomarker of disease activity and cardiometabolic risk factor in rheumatoid arthritis and spondyloarthritis

Objective

To analyze the relationship between complement component 3 (C3) and the prevalence of cardiometabolic risk factors and disease activity in the rheumatic diseases having the highest rates of cardiovascular morbidity and mortality: rheumatoid arthritis (RA), psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA).

Methods

This is a cross-sectional study including 200 RA, 80 PsA, 150 axSpA patients and 100 healthy donors. The prevalence of cardiometabolic risk factors [obesity, insulin resistance, type 2 diabetes mellitus, hyperlipidemia, apolipoprotein B/apolipoprotein A (apoB/apoA) and atherogenic risks and hypertension] was analyzed. Serum complement C3 levels, inflammatory markers and disease activity were evaluated. Cluster analysis was performed to identify different phenotypes. Receiver operating characteristic (ROC) curve analysis to assess the accuracy of complement C3 as biomarker of insulin resistance and disease activity was carried out.

Results

Levels of complement C3, significantly elevated in RA, axSpA and PsA patients, were associated with the prevalence of cardiometabolic risk factors. Hard clustering analysis identified two distinctive phenotypes of patients depending on the complement C3 levels and insulin sensitivity state. Patients from cluster 1, characterized by high levels of complement C3 displayed increased prevalence of cardiometabolic risk factors and high disease activity. ROC curve analysis showed that non-obesity related complement C3 levels allowed to identify insulin resistant patients.

Conclusions

Complement C3 is associated with the concomitant increased prevalence of cardiometabolic risk factors in rheumatoid arthritis and spondyloarthritis. Thus, complement C3 should be considered a useful marker of insulin resistance and disease activity in these rheumatic disorders.

Defective glucose and lipid metabolism in rheumatoid arthritis is determined by chronic inflammation in metabolic tissues

BACKGROUND

Rheumatoid arthritis (RA) patients are at increased risk of insulin resistance (IR); however, the specific mechanisms mediating this association are currently unknown.

OBJECTIVE

To investigate whether the inflammatory activity associated with RA accounts for the observed defective glucose metabolism and lipid metabolism in these patients.

METHODS

We followed two main strategies: (i) extensive metabolic profiling of a RA cohort of 100 patients and 50 healthy control subjects and (ii) mechanistic studies carried out in both a collagen-induced arthritis mouse model and 3T3-L1 adipocytes treated with conditioned serum from RA patients.

RESULTS

Following the exclusion of obese and diabetic subjects, data from RA patients demonstrated a strong link between the degree of systemic inflammation and the development of IR. These results were strengthened by the observation that induction of arthritis in mice resulted in a global inflammatory state characterized by defective carbohydrate and lipid metabolism in different tissues. Adipose tissue was most susceptible to the RA-induced metabolic alterations. These metabolic effects were confirmed in adipocytes treated with serum from RA patients.

CONCLUSIONS

Our results show that the metabolic disturbances associated with RA depend on the degree of inflammation and identify inflammation of adipose tissue as the initial target leading to IR and the associated molecular disorders of carbohydrate and lipid homeostasis. Thus, we anticipate that therapeutic strategies based on tighter control of inflammation and flares could provide promising approaches to normalize and/or prevent metabolic alterations associated with RA.

Circulating microRNAs as biomarkers of disease and typification of the atherothrombotic status in antiphospholipid syndrome

We aimed to identify the plasma miRNA profile of antiphospholipid syndrome (APS) patients and to investigate the potential role of specific circulating miRNAs as non-invasive disease biomarkers. Ninety APS patients and 42 healthy donors were recruited. Profiling of miRNAs by PCR-array in plasma of APS patients identified a set of miRNAs differentially expressed and collectively involved in clinical features. Logistic regression and ROC analysis identified a signature of 10 miRNA ratios as biomarkers of disease. In addition, miRNA signature was related to fetal loss, atherosclerosis, and type of thrombosis, and correlated with parameters linked to inflammation, thrombosis, and autoimmunity. Hard clustering analysis differentiated 3 clusters representing different thrombotic risk profile groups. Significant differences between groups for several miRNA ratios were found. Moreover, miRNA signature remained stable over time, demonstrated by their analysis three months after the first sample collection. Parallel analysis in two additional cohorts of patients, including thrombosis without autoimmune disease, and systemic lupus erythematosus without antiphospholipid antibodies, each displayed specific miRNA profiles that were distinct from those of APS patients. In vitro, antiphospholipid antibodies of IgG isotype promoted deregulation in selected miRNAs and their potential atherothrombotic protein targets in monocytes and endothelial cells. Taken together, differentially expressed circulating miRNAs in APS patients, modulated at least partially by antiphospholipid antibodies of IgG isotype, might have the potential to serve as novel biomarkers of disease features and to typify patients’ atherothrombotic status, thus constituting a useful tool in the management of the disease.

Ubiquinol Effects on Antiphospholipid Syndrome Prothrombotic Profile: A Randomized, Placebo-Controlled Trial

OBJECTIVE

Antiphospholipid syndrome (APS) leukocytes exhibit an oxidative perturbation, directly linked to alterations in mitochondrial dynamics and metabolism. This disturbance is related to the patients' prothrombotic status and can be prevented by in vitro treatment with coenzyme Q10. Our aim was to investigate short-term effects of in vivo ubiquinol (reduced coenzyme Q₁₀ [Q_red]) supplementation on markers related to inflammation and thrombosis in APS through a prospective, randomized, crossover, placebo-controlled trial.

APPROACH AND RESULTS

Thirty-six patients with APS were randomized to receive Q_red (200 mg/d) or placebo for 1 month. Thirty-three patients with APS completed the intervention, which increased plasma coenzyme Q₁₀. Q_red improved endothelial function and decreased monocyte expression of prothrombotic and proinflammatory mediators, inhibited phosphorylation of thrombosis-related protein kinases, and decreased peroxides and percentage of monocytes with depolarized mitochondria; mitochondrial size was increased, and mitochondrial biogenesis-related genes were upregulated. Q_red ameliorated extruded neutrophil extracellular traps in neutrophils and downregulated peroxides, intracellular elastase, and myeloperoxidase. Nanostring microRNA profiling revealed 20 microRNAs reduced in APS monocytes, and 16 of them, with a preponderance of cardiovascular disease-related target mRNAs, were upregulated. Monocytes gene profiling showed differential expression of 29 atherosclerosis-related genes, 23 of them changed by Q_red. Interaction networks of genes and microRNAs were identified. Correlation studies demonstrated co-ordinated effects of Q_red on thrombosis and endothelial function-associated molecules.

CONCLUSIONS

Our results highlight the potential of Q_red to modulate the overexpression of inflammatory and thrombotic risk markers in APS. Because of the absence of clinically significant side effects and its potential therapeutic benefits, Q_red might act as safe adjunct to standard therapies in APS.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02218476.

Diagnostic potential of NETosis-derived products for disease activity, atherosclerosis and therapeutic effectiveness in Rheumatoid Arthritis patients

OBJECTIVES

1) To assess the association of NETosis and NETosis-derived products with the activity of the disease and the development of cardiovascular disease in RA; 2) To evaluate the involvement of NETosis on the effects of biologic therapies such as anti-TNF alpha (Infliximab) and anti-IL6R drugs (Tocilizumab).

METHODS

One hundred and six RA patients and 40 healthy donors were evaluated for the occurrence of NETosis. Carotid-intimae media thickness was analyzed as early atherosclerosis marker. Inflammatory and oxidative stress mediators were quantified in plasma and neutrophils. Two additional cohorts of 75 RA patients, treated either with Infliximab (n = 55) or Tocilizumab (n = 20) for six months, were evaluated.

RESULTS

NETosis was found increased in RA patients, beside myeloperoxidase and neutrophil elastase protein levels. Cell-free nucleosomes plasma levels were elevated, and strongly correlated with the activity of the disease and the positivity for autoantibodies, alongside inflammatory and oxidative profiles in plasma and neutrophils. Moreover, ROC analyses showed that cell-free nucleosomes levels could identify RA patients showing early atherosclerosis with high specificity. RA patients treated either with IFX or TCZ for six months exhibited decreased generation of NETs. Concomitantly, clinical parameters and serum markers of inflammation were found reduced. Mechanistic in vitro analyses showed that inhibition of NETs extrusion by either DNase, IFX or TCZ, further abridged the endothelial dysfunction and the activation of immune cells, thus influencing the global activity of the vascular system.

CONCLUSIONS

NETosis-derived products may have diagnostic potential for disease activity and atherosclerosis, as well as for the assessment of therapeutic effectiveness in RA.