Glycosylation deficiency of lipopolysaccharide-binding protein and corticosteroid-binding globulin associated with activity and response to treatment for rheumatoid arthritis

Identification of serum exosomal miRNA biomarkers for diagnosis of Rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disorder characterized by inflammation-induced joint damage, which can cause lasting disability. Therefore, early diagnosis and treatment of RA are crucial. Herein, we evaluated whether exosomal microRNAs (miRNAs) could be served as promising biomarkers that can accelerate the diagnosis of RA and development of therapies for RA.

METHODS

First, we performed small RNA sequencing to determine the miRNA profiles of serum exosomes within a screening cohort comprised of 18 untreated active RA patients, along with 18 age and gender-matched healthy controls (HCs). Subsequently, the miRNA profiles were then validated in a training cohort consisting of 24 RA patients and 24 HCs by RT-qPCR. Finally, the selected exosomal miRNAs were validated in a larger cohort comprising 108 RA patients and 103 HCs. The diagnostic efficacy of the exosomal miRNAs was evaluated by receiver operating characteristic (ROC) curve analysis. Biological functions of the miRNAs were determined by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses.

RESULTS

Our results first demonstrated a noteworthy upregulation of three candidate miRNAs (miR-885-5p, miR-6894-3p, and miR-1268a) in the RA patients' serum exosomes compared to HCs. The combination of three miRNAs along with anti- citrullinated peptide antibodies (ACPA) exhibited excellent diagnostic accuracy, yielding an area under the curve (AUC) of 0.963 (95 % CI : 0.941-0.984), sensitivity of 87.96 %, and specificity of 93.20 %. Notably, miR-885-5p exhibited remarkable discriminatory capacity by itself in indistinguishing ACPA- negative RA patients from HCs, with an AUC of 0.993 (95 % CI : 0.978-1.000), sensitivity of 96.67 %, and specificity of 100 %. Moreover, the expression of miR-1268a in the assessment of therapeutic effectiveness displayed significant reduction on 29th day of Methotrexate (MTX) treatment in RA patients. This decreased expression paralleled with trends observed in tender 28-joint count (TJC28), swollen 28-joint count (SJC28), and disease activity score with 28-joint count using C-reactive protein (DAS28-CRP), all of which are indicative of RA disease activity. Finally, predictive analysis indicated that, these three exosomal miRNAs target pivotal signaling molecules involved in inflammatory pathways, thereby demonstrating effective modulation of the immune system.

CONCLUSIONS

In this study, we successfully demonstrated the promising potential for serum exosomal miRNAs, particularly miR-885-5p, miR-6894-3p and miR-1268a as biomarkers for early diagnosis and prediction of RA for the first time.

Tailored therapeutic decision of rheumatoid arthritis using proteomic strategies: how to start and when to stop?

Unpredictable treatment responses have been an obstacle for the successful management of rheumatoid arthritis. Although numerous serum proteins have been proposed, there is a lack of integrative survey to compare their relevance in predicting treatment outcomes in rheumatoid arthritis. Also, little is known about their applications in various treatment stages, such as dose modification, drug switching or withdrawal. Here we present an in-depth exploration of the potential usefulness of serum proteins in clinical decision-making and unveil the spectrum of immunopathology underlying responders to different drugs. Patients with robust autoimmunity and inflammation are more responsive to biological treatments and prone to relapse during treatment de-escalation. Moreover, the concentration changes of serum proteins at the beginning of the treatments possibly assist early recognition of treatment responders. With a better understanding of the relationship between the serum proteome and treatment responses, personalized medicine in rheumatoid arthritis will be more achievable in the near future.

Lipopolysaccharide-binding protein and bone health: data from a population-based sample of men

We aimed to investigate the association between serum lipopolysaccharide-binding protein (LBP) and bone health in men. LBP was associated with lower bone density at the mid-forearm and the quantitative heel ultrasound measure, broadband ultrasound attenuation, for heavier participants. Data do not support clear associations between serum LBP and bone health.

INTRODUCTION

The objective of this study was to investigate the association between serum lipopolysaccharide-binding protein (LBP) and potential downstream effects on skeletal density, quality, and turnover in a population-based sample of men.

METHODS

This cross-sectional study utilised data from 1149 men (aged 20-96 year) enrolled in the Geelong Osteoporosis Study. Blood samples were obtained and lipopolysaccharide-binding protein (LBP), bone resorption marker, C-telopeptide (CTx), and formation marker, type 1 procollagen amino-terminal-propeptide (P1NP), were measured. Bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry. Stiffness Index (SI), broadband ultrasound attenuation (BUA), and speed of sound (SOS) were derived from quantitative heel ultrasound (QUS). Linear regression models were developed to test associations between log-transformed LBP (ln-LBP), BMD, QUS, and bone turnover, after adjusting for potential covariates.

RESULTS

Serum LBP ranged from 1.07-208.53 ng/mL (median 16.53 ng/mL). Those with higher levels were older, less mobile, and had lower BMD at the mid-forearm, otherwise, groups were similar. Before and after adjustment for age, ln-LBP was associated with lower BMD at the spine, total body, and mid-forearm. Further adjustment for weight attenuated associations at the spine and total body, yet the relationship at the mid-forearm was sustained (β - 0.014 ± 0.004, p = 0.001). SOS and SI were not associated with ln-LBP either before or after adjustment for age; however, weight was identified as an effect modifier in the relationship between ln-LBP and BUA. An association was observed for those weighing greater than 82.7 kg (β 3.366 ± 0.929, p < 0.001), after adjustment for potential covariates. Neither bone turnover marker was associated with ln-LBP.

CONCLUSION

Our data do not support a clear association between serum LBP and measures of bone health in this sample of men.

Aberrant Cellular Glycosylation May Increase the Ability of Influenza Viruses to Escape Host Immune Responses through Modification of the Viral Glycome

Individuals with metabolic dysregulation of cellular glycosylation often experience severe influenza disease, with a poor immune response to the virus and low vaccine efficacy. Here, we investigate the consequences of aberrant cellular glycosylation for the glycome and the biology of influenza virus. We transiently induced aberrant N-linked glycosylation in cultured cells with an oligosaccharyltransferase inhibitor, NGI-1. Cells treated with NGI-1 produced morphologically unaltered viable influenza virus with sequence-neutral glycosylation changes (primarily reduced site occupancy) in the hemagglutinin and neuraminidase proteins. Hemagglutinin with reduced glycan occupancy required a higher concentration of surfactant protein D (an important innate immunity respiratory tract collectin) for inhibition compared to that with normal glycan occupancy. Immunization of mice with NGI-1-treated virus significantly reduced antihemagglutinin and antineuraminidase titers of total serum antibody and reduced hemagglutinin protective antibody responses. Our data suggest that aberrant cellular glycosylation may increase the risk of severe influenza as a result of the increased ability of glycome-modified influenza viruses to evade the immune response.

Serum calprotectin (S100A8/A9): a promising biomarker in diagnosis and follow-up in different subgroups of juvenile idiopathic arthritis

Introduction

In the management of juvenile idiopathic arthritis (JIA), there is a lack of diagnostic and prognostic biomarkers. This study assesses the use of serum calprotectin (sCal) as a marker to monitor disease activity, and as a classification and prognosis tool of response to treatment or risk of flares in patients with JIA.

Methods

Eighty-one patients with JIA from the CAP48 multicentric cohort were included in this study, as well as 11 non-paediatric healthy controls. An ELISA method was used to quantify sCal with a commercial kit.

Results

Patients with an active disease compared with healthy controls and with patients with inactive disease showed an eightfold and a twofold increased level of sCal, respectively. sCal was found to be correlated with the C-reactive protein (CRP) and even more strongly with the erythrocyte sedimentation rate. Evolution of DAS28 scores correlated well with evolution of sCal, as opposed to evolution of CRP. With regard to CRP, sCal could differentiate forms with active oligoarthritis from polyarthritis and systemic forms. However, sCal brought an added value compared with the CRP as a prognosis marker. Indeed, patients with active disease and reaching minimal disease activity (according to Juvenile Arthritis Disease Activity Score) at 6 months following the test had higher sCal levels, while patients with inactive disease had higher sCal levels if a flare was observed up to 3–9 months following the test.

Conclusions

This study confirms the potential uses of sCal as a biomarker in the diagnosis and follow-up of JIA.

Exchanging dietary fat source with extra virgin olive oil does not prevent progression of diet-induced non-alcoholic fatty liver disease and insulin resistance

Dietary fat is discussed to be critical in the development of non-alcoholic fatty liver disease. Here, we assess the effect of exchanging dietary fat source from butterfat to extra virgin olive oil on the progression of an already existing diet-induced non-alcoholic fatty liver disease in mice. Female C57BL/6J mice were fed a liquid butterfat-, fructose- and cholesterol-rich diet (BFC, 25E% from butterfat) or control diet (C, 12%E from soybean oil) for 13 weeks. In week 9, fat sources of some BFC- and C-fed mice were switched either to 25E% or 12E% olive oil (OFC and CO). Glucose and insulin tolerance tests were performed, and markers of liver damage and glucose metabolism were assessed. After 6 weeks of feeding, BFC-fed mice had developed marked signs of insulin resistance, which progressed to week 12 being not affected by the exchange of fat sources. Liver damage was similar between BFC- and OFC-fed mice. Markers of lipid metabolism and lipid peroxidation in liver and of insulin signaling in liver and muscle were also similarly altered in BFC- and OFC-fed mice. Taken together, our data suggest that exchanging butterfat with extra virgin olive oil has no effect on the progression of non-alcoholic fatty liver disease and glucose tolerance in mice.

Glycosylation may influence sex hormone-binding globulin measurements

A discordance between sex hormone-binding globulin (SHBG) measurements by 2-site ELISAs was investigated using pairings of various "in house" SHBG antibodies together with a concordant control. The 2-site monoclonal ELISAs used the same base coat (11F11) and discordance was observed with one top coat monoclonal antibody (7H9) and also when a polyclonal SHBG antibody was paired with the basecoat antibody (11F11). Sialidase treatment of the discordant sample and purified SHBG revealed increased levels using 7H9 whereas there was no change in SHBG in the concordant sample. Conversely, following sialidase treatment, the discordant sample showed no change in SHBG measured using the other monoclonal antibody pairings whereas the SHBG levels in the concordant sample declined following sialidase using the same monoclonal antibody pairings. This implicated glycosylation as a factor in antibody recognition and synthetic peptides spanning the two N-linked and one O-linked glycosylation regions showed that SHBG recognition by monoclonal antibody 7H9 could be disrupted by a peptide spanning the O-linked glycosylation site. Hence rather than immunoassay discordance being attributed to heterophile antibodies or other circulating antibodies here it can be likely attributed to glycosylation affecting antibody recognition and hence the measurement of SHBG.