Baseline Serum Concentrations of TRAIL in Early Rheumatoid Arthritis: Relationship with Response to Disease-modifying Antirheumatic Drugs

Exploring the dynamic role of circulating soluble tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as a diagnostic and prognostic marker; a review

Tumor necrosis factor (TNF) related apoptosis-inducing ligand (TRAIL) is a TNF superfamily cytokine primarily acknowledged for its ability to selectively induce apoptosis in cancer cells. Beyond its antitumor effects, recent literature emphasizes the pleiotropic functions of TRAIL in physiological states and acute/chronic non-malignant diseases indicating its potential to be a breakthrough in diagnostics. This review explores the current understanding of the dynamic role of circulating soluble TRAIL (sTRAIL) and its potential as both a diagnostic and prognostic marker. Multiple in vitro, in vivo, and clinical studies in a wide range of neoplastic and non-neoplastic diseases including infectious diseases have been carried out to explore the potential role of sTRAIL in disease pathogenesis and as well as the possibilities of using it as a diagnostic and prognostic marker. The expression of sTRAIL seems to be context-dependent suggesting further research, particularly towards establishing disease-specific cutoff values. However, the lack of standardization in the serum sTRAIL estimation and the absence of reference intervals remain significant barriers to its clinical application. Addressing these challenges is essential for using circulating sTRAIL as an accurate diagnostic and prognostic marker in clinical practice.

Serum-soluble TRAIL: a potential biomarker for disease activity in myositis patients

OBJECTIVES

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the TNF super-family, which is involved in the regulation of immune response and pathogenesis of autoimmune diseases, including polymyositis (PM) and dermatomyositis (DM). In this study, we examined the level and origin of serum-soluble TRAIL (sTRAIL) in patients with PM and DM and analyzed its association with disease activity and clinical features.

METHOD

11 PM patients, 33 DM patients, and 20 healthy controls were enrolled in this study. Clinical features were recorded when admitted, and disease activity was evaluated by myositis disease activity assessment visual analogue scale (MYOACT). TRAIL expression in muscle tissues was detected by immunohistochemistry. Serum sTRAIL levels were measured by enzyme-linked immunosorbent assay. The expression of membrane TRAIL (mTRAIL) and its receptors, including DR4 and DR5, on circulating T cells was analyzed by flow cytometry.

RESULTS

TRAIL was expressed in infiltrated inflammatory cells in muscle tissues from patients. The serum sTRAIL level was markedly increased in patients and was positively correlated with the disease activity. Serum sTRAIL was decreased after therapy in patients and was specifically higher in patients with dysphagia, but lower in patients with autoantibody Jo-1 positive. The frequency of mTRAIL and its receptors on circulating T cells from patients were significantly elevated than that from healthy controls.

CONCLUSIONS

The serum sTRAIL could be a biomarker for evaluating the disease activity of PM and DM, and targeting the generation of TRAIL in T cells might be a potential approach in the treatment of PM and DM.

Anti-interleukin-6 signalling therapy rebalances the disrupted cytokine production of B cells from patients with active rheumatoid arthritis

Rheumatoid arthritis (RA) is associated with abnormal B cell-functions implicating antibody-dependent and -independent mechanisms. B cells have emerged as important cytokine-producing cells, and cytokines are well-known drivers of RA pathogenesis. To identify novel cytokine-mediated B-cell functions in RA, we comprehensively analysed the capacity of B cells from RA patients with an inadequate response to disease modifying anti-rheumatic drugs to produce cytokines in comparison with healthy donors (HD). RA B cells displayed a constitutively higher production of the pathogenic factors interleukin (IL)-8 and Gro-α, while their production of several cytokines upon activation via the B cell receptor for antigen (BCR) was broadly suppressed, including a loss of the expression of the protective factor TRAIL, compared to HD B cells. These defects were partly erased after treatment with the IL-6-signalling inhibitor tocilizumab, indicating that abnormal IL-6 signalling contributed to these abnormalities. Noteworthy, the clinical response of individual patients to tocilizumab therapy could be predicted using the amounts of MIP-1β and β-NGF produced by these patients' B cells before treatment. Taken together, our study highlights hitherto unknown abnormal B-cell functions in RA patients, which are related to the unbalanced cytokine network, and are potentially relevant for RA pathogenesis and treatment.

Brief Report: Autocrine Cytokine-Mediated Deficiency of TRAIL-Induced Monocyte Apoptosis in Rheumatoid Arthritis

OBJECTIVE

Dysregulated apoptosis of monocytes is a pathogenic feature of rheumatoid arthritis (RA). The aim of this study was to investigate the role of TRAIL and TRAIL-induced apoptosis in patients with RA.

METHODS

Cell surface expression and serum concentrations of TRAIL were determined in 63 patients with RA, and TRAIL-induced monocyte apoptosis was quantified. Surface expression of TRAILR-1, TRAILR-2, TRAILR-3, TRAILR-4, CXCR1, and CXCR2 was determined, and intracellular signal transduction was investigated. In 8 patients with RA, clinical and laboratory parameters of disease activity were investigated longitudinally, before and after initiation of treatment with tumor necrosis factor (TNF) inhibitors.

RESULTS

Serum concentrations of both TRAIL and interleukin-8 (IL-8) were increased in patients with RA, while cell surface expression of the TRAIL receptors TRAILR-1, TRAILR-2, TRAILR-3, and TRAILR-4 was diminished. TRAIL-induced monocyte apoptosis was significantly decreased in RA due to increased TRAIL-induced IL-8 secretion by RA monocytes. The combined effect of TRAIL and IL-8 on monocytes resulted in activation of antiapoptotic pathways, including p42/44 MAPK and p38. Susceptibility to TRAIL-induced apoptosis was restored in RA monocytes after 3 months of TNF inhibition.

CONCLUSION

In RA, circulating monocytes with the potential to produce proinflammatory cytokines appear to have defects in several pathways of apoptosis induction, among which is a deficiency in TRAIL-induced apoptosis. Although this resistance to apoptosis might contribute to perpetuation of the disease, it remains to be determined whether specific induction of apoptosis could be therapeutically beneficial.

Patients with ankylosing spondylitis and low disease activity because of anti-TNF-alpha therapy have higher TRAIL levels than controls: a potential compensatory effect

OBJECTIVE

TRAIL is a potential biomarker of cardiovascular (CV) disease. Ankylosing spondylitis (AS) is a chronic inflammatory disease associated with metabolic syndrome (MeS) and accelerated atherosclerosis. We assessed whether disease activity, systemic inflammation, and MeS features were associated with circulating TRAIL levels in AS patients undergoing TNF-α antagonist infliximab therapy and if infliximab infusion modified TRAIL levels.

METHODS

We measured TRAIL serum levels in 30 nondiabetic AS patients without CV disease undergoing anti-TNF-α therapy, immediately before and after an infliximab infusion, and in 48 matched controls. Correlations of TRAIL levels with disease activity, systemic inflammation and MeS features, adipokines, and biomarkers of endothelial activation were evaluated. Changes in TRAIL levels following anti-TNF-α infusion were analyzed.

RESULTS

TRAIL levels were higher in AS patients than controls. TRAIL levels displayed an inverse correlation with total and LDL cholesterol. We observed an inverse correlation with QUICKI and a marginal association with HOMA-IR. We also found an inverse correlation with resistin and a marginal association with apelin and OPN. Anti-TNF-α infusion did not change TRAIL levels after 120'.

CONCLUSION

Elevated TRAIL levels in AS patients may be the result of a compensatory mechanism to reduce CV risk in these patients.

TNF-related apoptosis-inducing ligand (TRAIL) in rheumatoid arthritis: what's new?

TNF-related apoptosis-inducing ligand (TRAIL) is a type II transmembrane protein of the TNF superfamily that serves as an extracellular signal that triggers programmed cell death in tumor cells, without affecting normal cells. Recently, scientists have turned their attention to the emerging role of TRAIL in immune and autoimmune responses. TRAIL has been shown to down-regulate the self-antigens in autoimmune diseases, such as rheumatoid arthritis (RA) by exerting its apoptotic effect on activated T cells and synoviocytes and by its local anti-inflammatory effect. The impact of TRAIL molecular variants and agonistic monoclonal antibodies in the regulation of TRAIL activity in arthritis animal models strongly supports the idea of testing the role of TRAIL in humans, with the aim of developing new effective therapies that promote apoptosis of synoviocytes and/or infiltrating lymphocytes, by targeting TRAIL. The aim of this review is to summarize recent progress and current knowledge of TRAIL functions in RA.