Low expression of CD39 on regulatory T cells as a biomarker for resistance to methotrexate therapy in rheumatoid arthritis

Pathophysiology, diagnosis, and herbal medicine-based therapeutic implication of rheumatoid arthritis: an overview

Rheumatoid arthritis (RA) stands as an autoimmune disorder characterized by chronic joint inflammation, resulting in profound physiological alterations within the body. Affecting approximately 0.4-1.3% of the global population, this condition poses significant challenges as current therapeutic approaches primarily offer symptomatic relief, with the prospect of complete recovery remaining elusive. This review delves into the contemporary advancements in understanding the pathophysiology, diagnosis, and the therapeutic potential of herbal medicine in managing RA. Notably, early diagnosis during the initial stages emerges as the pivotal determinant for successful recovery post-treatment. Utilizing tools such as Magnetic Resonance Imaging (MRI), anti-citrullinated peptide antibody markers, and radiography proves crucial in pinpointing the diagnosis of RA with precision. Unveiling the intricate pathophysiological mechanisms of RA has paved the way for innovative therapeutic interventions, incorporating plant extracts and isolated phytoconstituents. In the realm of pharmacological therapy for RA, specific disease-modifying antirheumatic drugs have showcased commendable efficacy. However, this conventional approach is not without its drawbacks, as it is often associated with various side effects. The integration of methodological strategies, encompassing both pharmacological and plant-based herbal therapies, presents a promising avenue for achieving substantive recovery. This integrated approach not only addresses the symptoms but also strives to tackle the underlying causes of RA, fostering a more comprehensive and sustainable path towards healing.

Proteomics analyses of human plasma reveal triosephosphate isomerase as a potential blood marker of methotrexate resistance in rheumatoid arthritis

OBJECTIVE

The objective of this study was to assess differentially expressed blood proteins between patients with active RA and patients in remission after MTX treatment, with the aim of identifying a biomarker of MTX resistance (MTXR).

METHODS

Two populations of RA patients treated with a stable dose of s.c. MTX for at least 3 months were constituted according to the DAS28: remission (DAS28 < 2.6; n = 24) and active disease (DAS28 > 3.2; n = 32). The two groups of RA patients were homogeneous regarding their epidemiological characteristics, except for the duration of treatment, which was longer in the remission group. After collection of a blood sample, plasma protein digestion was performed, followed by untargeted proteomics analysis. Then, a targeted analysis was performed to confirm the results of the untargeted approach.

RESULTS

Untargeted proteomics analysis revealed eight plasma proteins that were differentially expressed between the two groups of patients. Among them, triosephosphate isomerase (TPI-1) and glucose-6-phosphate isomerase (GPI), which are main actors in glycolysis, were found down-regulated in the active group. This result was confirmed for TPI-1 in the targeted proteomics analysis.

CONCLUSION

A first step was achieved in the search for biomarkers of MTXR, with the identification of two actors in glycolysis (TPI-1 and GPI). The next step will be to confirm these results in a larger cohort, including samples from treatment-naive patients, to assess the predictive potential of these protein markers.

The Biologic IRL201805 Alters Immune Tolerance Leading to Prolonged Pharmacodynamics and Efficacy in Rheumatoid Arthritis Patients

A homologue of binding immunoglobulin protein/BiP-IRL201805 alters the function of immune cells in pre-clinical in vivo and in vitro studies. The aim of the study was to select biomarkers that clearly delineate between RA patients who respond to IRL201805 and placebo patients and reveal the immunological mode of action of IRL201805 driving the extended pharmacodynamics observed in responding patients. Biomarkers that distinguished between responding patients and placebo patients included downregulation of serum interferon-γ and IL-1β; upregulation of anti-inflammatory mediators, serum soluble CTLA-4, and intracellular monocyte expression of IDO; and sustained increased CD39 expression on CD3+CD4+CD25hi CD127lo regulatory T cells. In the responding patients, selected biomarkers verified that the therapeutic effect could be continuous for at least 12 weeks post-infusion. In secondary co-culture, pre-infusion PBMCs cultured 1:1 with autologous PBMCs, isolated at later time-points during the trial, showed significantly inhibited IL-6 and IL-1β production upon anti-CD3/CD28 stimulation demonstrating IRL201805 alters the function of immune cells leading to prolonged pharmacodynamics confirmed by biomarker differences. IRL201805 may be the first of a new class of biologic drug providing long-term drug-free therapy in RA.

Adenosine metabolic signature in circulating CD4+ T cells predicts remission in rheumatoid arthritis

OBJECTIVES

Long-term outcomes in rheumatoid arthritis (RA) depend on early and effective disease control. Methotrexate (MTX) remains the first-line disease modifying therapy, however there are no biomarkers with which to identify those most likely to achieve remission. To address this unmet need we explored metabolic pathways involved in MTX mechanism of action within circulating CD4+T cells in a cohort of treatment naive patients with early RA.

METHODS

Purified CD4+T cells were isolated from peripheral blood of 68 patients with early RA commencing MTX. The expression of a range of putative MTX metabolism and mechanism of action targets were explored by flow-cytometry and transcriptional analysis. From these data significant predictors of Disease Activity Score 28-C reactive protein (DAS28-CRP) remission (<2.4 at 6 months) were determined by logistic regression (clinical; flow-cytometry data) and linear modelling (gene expression data).

RESULTS

Low baseline DAS28-CRP was associated with remission at 6 months (p=0.02). Expression of the ectonucleotidase CD39, involved in ATP-ADP conversion during adenosine synthesis, was higher on CD4+CD25 High regulatory T cells at baseline in those achieving remission (molecules of equivalent fluorescence 1264 vs 847; p=0.007). Expression of other adenosine signalling elements in CD4+T cells were also upregulated at baseline in patients achieving remission: AMPD1 (p<0.001), ADORA2b (p=0.039) and ADORA3 (p=0.047). When combined into a single predictive metric, a combination of these variables outperformed baseline DAS28-CRP in prediction of early remission (area under the curve 0.92 vs 0.67, p=0.001) CONCLUSIONS: Adenosine signalling is important in the achievement of early remission with MTX in RA and biomarkers of adenosine activity may hold utility for the stratification of therapy in early disease.

Single-cell insights into immune dysregulation in rheumatoid arthritis flare versus drug-free remission

Immune-mediated inflammatory diseases (IMIDs) are typically characterised by relapsing and remitting flares of inflammation. However, the unpredictability of disease flares impedes their study. Addressing this critical knowledge gap, we use the experimental medicine approach of immunomodulatory drug withdrawal in rheumatoid arthritis (RA) remission to synchronise flare processes allowing detailed characterisation. Exploratory mass cytometry analyses reveal three circulating cellular subsets heralding the onset of arthritis flare - CD45RO+PD1hi CD4+ and CD8+ T cells, and CD27+CD86+CD21- B cells - further characterised by single-cell sequencing. Distinct lymphocyte subsets including cytotoxic and exhausted CD4+ memory T cells, memory CD8+CXCR5+ T cells, and IGHA1+ plasma cells are primed for activation in flare patients. Regulatory memory CD4+ T cells (Treg cells) increase at flare onset, but with dysfunctional regulatory marker expression compared to drug-free remission. Significant clonal expansion is observed in T cells, but not B cells, after drug cessation; this is widespread throughout memory CD8+ T cell subsets but limited to the granzyme-expressing cytotoxic subset within CD4+ memory T cells. Based on our observations, we suggest a model of immune dysregulation for understanding RA flare, with potential for further translational research towards novel avenues for its treatment and prevention.

Altered CD39 and CD73 Expression in Rheumatoid Arthritis: Implications for Disease Activity and Treatment Response

In rheumatoid arthritis (RA) synovium, ATP, and ADP are released, sparking inflammation. Ectoenzymes CD39 and CD73 metabolize these purine nucleotides, generating anti-inflammatory adenosine. Therefore, dysregulated CD39 and CD73 expression may impact RA development. We assessed CD39 and CD73 expression in peripheral blood from 15 healthy controls (Cs) and 35 RA patients at baseline and after 3 and 6 months of tocilizumab treatment using flow cytometry. Additionally, ectoenzyme expression was examined on cultured T cells to understand activation and IL-6 effects. At baseline, RA patients exhibited a lower CD8+CD39-CD73+ cell percentage, which inversely correlated with DAS28. Additionally, they had lower percentages of Treg CD39+CD73+ and CD39-CD73- cells. Good responders tended to have lower B CD39+CD73+ cell percentages at baseline and 3 months. Additionally, Treg, CD8+ T and B cells inversely correlated with DAS28. T-cell activation increased CD39 and decreased CD73 expression, regardless of IL-6. IL-6 reduced IFNγ-secreting CD4+ T-cell percentage in Cs, but increased the percentage of IFNγ-secreting CD4+ and CD8+ T cells in RA patients. These findings indicate differing CD39 and CD73 expression in RA and Cs, influenced by T-cell activation and IL-6. Correlations between these molecules and RA activity suggest their role in dysregulated inflammation in RA.

CD39 expression on immune cells predicts methotrexate response in rheumatoid arthritis patients

Background/aim

Rheumatoid arthritis (RA) is a chronic inflammatory disease affecting mostly small joints, such as hand and foot joints symmetrically with irreversible joint destruction. In this study, the relationship between CD39 expression and the treatment response of RA patients was examined to investigate its potential as a biomarker that demonstrates treatment response.

Materials and methods

This study included 77 RA patients and 40 healthy controls (HC). The RA patients were divided into 2 groups based on their response to RA treatment, those with a good response to methotrexate (MTX) monotherapy and those with an inadequate response based on the American College of Rheumatology and the European League Against Rheumatism response criteria. Various immunological parameters and Disease Activity Score in 28 Joints (DAS28) were examined between the groups using the Student's t-test.

Results

The monocytic myeloid-derived suppressor cell (M-MDSC) percentage was higher in the RA patient group versus the HC group. The CD39 expression in the T lymphocytes were higher in patients that responded well to the MTX compared to those showing inadequate response. Additionally, s negative correlation was found between the DAS28 and CD39 in the T cells.

Conclusion

The results showed that the improvement in treatment response to the therapy in RA patients could be because of the enhancement in the CD39/adenosine (ADO) pathway. Therefore, therapies targeting the CD39/ADO pathway in T cells may improve RA treatments.

Drugs targeting adenosine signaling pathways: A current view

Adenosine is an endogenous nucleoside that regulates many physiological and pathological processes. It is derived from either the intracellular or extracellular dephosphorylation of adenosine triphosphate and interacts with cell-surface G-protein-coupled receptors. Adenosine plays a substantial role in protecting against cell damage in areas of increased tissue metabolism and preventing organ dysfunction in pathological states. Targeting adenosine metabolism and receptor signaling may be an effective therapeutic approach for human diseases, including cardiovascular and central nervous system disorders, rheumatoid arthritis, asthma, renal diseases, and cancer. Several lines of evidence have shown that many drugs exert their beneficial effects by modulating adenosine signaling pathways but this knowledge urgently needs to be summarized, and most importantly, actualized. The present review collects pharmaceuticals and pharmacological or diagnostic tools that target adenosine signaling in their primary or secondary mode of action. We overviewed FDA-approved drugs as well as those currently being studied in clinical trials. Among them are already used in clinic A2A adenosine receptor modulators like istradefylline or regadenoson, but also plenty of anti-platelet, anti-inflammatory, or immunosuppressive, and anti-cancer drugs. On the other hand, we investigated dozens of specific adenosine pathway regulators that are tested in clinical trials to treat human infectious and noninfectious diseases. In conclusion, targeting purinergic signaling represents a great therapeutic challenge. The actual knowledge of the involvement of adenosinergic signaling as part of the mechanism of action of old drugs has open a path not only for drug-repurposing but also for new therapeutic strategies.

Methotrexate Provokes Disparate Folate Metabolism Gene Expression and Alternative Splicing in Ex Vivo Monocytes and GM-CSF- and M-CSF-Polarized Macrophages

Macrophages constitute important immune cell targets of the antifolate methotrexate (MTX) in autoimmune diseases, including rheumatoid arthritis. Regulation of folate/MTX metabolism remains poorly understood upon pro-inflammatory (M1-type/GM-CSF-polarized) and anti-inflammatory (M2-type/M-CSF-polarized) macrophages. MTX activity strictly relies on the folylpolyglutamate synthetase (FPGS) dependent intracellular conversion and hence retention to MTX-polyglutamate (MTX-PG) forms. Here, we determined FPGS pre-mRNA splicing, FPGS enzyme activity and MTX-polyglutamylation in human monocyte-derived M1- and M2-macrophages exposed to 50 nmol/L MTX ex vivo. Moreover, RNA-sequencing analysis was used to investigate global splicing profiles and differential gene expression in monocytic and MTX-exposed macrophages. Monocytes displayed six-eight-fold higher ratios of alternatively-spliced/wild type FPGS transcripts than M1- and M2-macrophages. These ratios were inversely associated with a six-ten-fold increase in FPGS activity in M1- and M2-macrophages versus monocytes. Total MTX-PG accumulation was four-fold higher in M1- versus M2-macrophages. Differential splicing after MTX-exposure was particularly apparent in M2-macrophages for histone methylation/modification genes. MTX predominantly induced differential gene expression in M1-macrophages, involving folate metabolic pathway genes, signaling pathways, chemokines/cytokines and energy metabolism. Collectively, macrophage polarization-related differences in folate/MTX metabolism and downstream pathways at the level of pre-mRNA splicing and gene expression may account for variable accumulation of MTX-PGs, hence possibly impacting MTX treatment efficacy.

Differential regulatory T cell signature after recovery from mild COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is characterized by a range of symptoms in which host immune response have been associated with disease progression. However, the putative role of regulatory T cells (Tregs) in determining COVID-19 outcomes has not been thoroughly investigated. Here, we compared peripheral Tregs between volunteers not previously infected with SARS-CoV-2 (healthy control [HC]) and volunteers who recovered from mild (Mild Recovered) and severe (Severe Recovered) COVID-19. Peripheral blood mononuclear cells (PBMC) were stimulated with SARS-CoV-2 synthetic peptides (Pool Spike CoV-2 and Pool CoV-2) or staphylococcal enterotoxin B (SEB). Results of a multicolor flow cytometric assay showed higher Treg frequency and expression of IL-10, IL-17, perforin, granzyme B, PD-1, and CD39/CD73 co-expression in Treg among the PBMC from the Mild Recovered group than in the Severe Recovered or HC groups for certain SARS-CoV-2 related stimulus. Moreover, Mild Recovered unstimulated samples presented a higher Tregs frequency and expression of IL-10 and granzyme B than did that of HC. Compared with Pool CoV-2 stimuli, Pool Spike CoV-2 reduced IL-10 expression and improved PD-1 expression in Tregs from volunteers in the Mild Recovered group. Interestingly, Pool Spike CoV-2 elicited a decrease in Treg IL-17+ frequency in the Severe Recovered group. In HC, the expression of latency-associated peptide (LAP) and cytotoxic granule co-expression by Tregs was higher in Pool CoV-2 stimulated samples. While Pool Spike CoV-2 stimulation reduced the frequency of IL-10+ and CTLA-4+ Tregs in PBMC from volunteers in the Mild Recovered group who had not experienced certain symptoms, higher levels of perforin and perforin+granzyme B+ co-expression by Tregs were found in the Mild Recovered group in volunteers who had experienced dyspnea. Finally, we found differential expression of CD39 and CD73 among volunteers in the Mild Recovered group between those who had and had not experienced musculoskeletal pain. Collectively, our study suggests that changes in the immunosuppressive repertoire of Tregs can influence the development of a distinct COVID-19 clinical profile, revealing that a possible modulation of Tregs exists among volunteers of the Mild Recovered group between those who did and did not develop certain symptoms, leading to mild disease.

The impact of the gut microbiome on extra-intestinal autoimmune diseases

The prevalence of autoimmune diseases (ADs) worldwide has rapidly increased over the past few decades. Thus, in addition to the classical risk factors for ADs, such as genetic polymorphisms, infections and smoking, environmental triggers have been considered. Recent sequencing-based approaches have revealed that patients with extra-intestinal ADs, such as multiple sclerosis, rheumatoid arthritis, type 1 diabetes and systemic lupus erythematosus, have distinct gut microbiota compositions compared to healthy controls. Faecal microbiota transplantation or inoculation with specific microbes in animal models of ADs support the hypothesis that alterations of gut microbiota influence autoimmune responses and disease outcome. Here, we describe the compositional and functional changes in the gut microbiota in patients with extra-intestinal AD and discuss how the gut microbiota affects immunity. Moreover, we examine how the gut microbiota might be modulated in patients with ADs as a potential preventive or therapeutic approach.

-Omic Approaches and Treatment Response in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an inflammatory disorder characterized by an aberrant activation of innate and adaptive immune cells. There are different drugs used for the management of RA, including disease-modifying antirheumatic drugs (DMARDs). However, a significant percentage of RA patients do not initially respond to DMARDs. This interindividual variation in drug response is caused by a combination of environmental, genetic and epigenetic factors. In this sense, recent -omic studies have evidenced different molecular signatures involved in this lack of response. The aim of this review is to provide an updated overview of the potential role of -omic approaches, specifically genomics, epigenomics, transcriptomics, and proteomics, to identify molecular biomarkers to predict the clinical efficacy of therapies currently used in this disorder. Despite the great effort carried out in recent years, to date, there are still no validated biomarkers of response to the drugs currently used in RA. -Omic studies have evidenced significant differences in the molecular profiles associated with treatment response for the different drugs used in RA as well as for different cell types. Therefore, global and cell type-specific -omic studies analyzing response to the complete therapeutical arsenal used in RA, including less studied therapies, such as sarilumab and JAK inhibitors, are greatly needed.

IL-6-Driven pSTAT1 Response Is Linked to T Cell Features Implicated in Early Immune Dysregulation

Elevated levels and enhanced sensing of the pro-inflammatory cytokine interleukin-6 (IL-6) are key features of many autoimmune and inflammatory diseases. To better understand how IL-6 signaling may influence human T cell fate, we investigated the relationships between levels of components of the IL-6R complex, pSTAT responses, and transcriptomic and translational changes in CD4+ and CD8+ T cell subsets from healthy individuals after exposure to IL-6. Our findings highlight the striking heterogeneity in mbIL-6R and gp130 expression and IL-6-driven pSTAT1/3 responses across T cell subsets. Increased mbIL-6R expression correlated with enhanced signaling via pSTAT1 with less impact on pSTAT3, most strikingly in CD4+ naïve T cells. Additionally, IL-6 rapidly induced expression of transcription factors and surface receptors expressed by T follicular helper cells and altered expression of markers of apoptosis. Importantly, many of the features associated with the level of mbIL-6R expression on T cells were recapitulated both in the setting of tocilizumab therapy and when comparing donor CD4+ T cells harboring the genetic variant, IL6R Asp358Ala (rs2228145), known to alter mbIL-6R expression on T cells. Collectively, these findings should be taken into account as we consider the role of IL-6 in disease pathogenesis and translating IL-6 biology into effective therapies for T cell-mediated autoimmune disease.

Methotrexate promotes recovery of arthritis-induced alveolar bone loss and modifies the composition of the oral-gut microbiota

OBJECTIVES

The impact of rheumatoid arthritis (RA) on the shaping of the oral and gut microbiome raises the question of whether and how RA treatment modifies microbial communities. We examined changes in the oral and gut microbiota in a mouse model of antigen-induced arthritis (AIA) treated or not with methotrexate (MTX).

METHODS

Maxillae and stools were evaluated by the MiSeq platform of the V4 region of the 16S rRNA gene. Alveolar bone parameters were analysed by micro-computed tomography. Moreover, arthritis-induced changes in hyperalgesia and oedema were assessed, along with the impact on periodontal bone health.

RESULTS

Microbial communities in MTX-treated AIA mice revealed distinct clusters compared to the control and AIA groups. Overall, MTX impacted the richness and variability of microorganisms in the oral-gut axis microbiome at the phylum level. Regarding the oral microbiome, while in the control group the most dominant phylum was Firmicutes, in the AIA group there was a shift towards the predominance of Campilobacteriota and Bacteroidetes associated with the disease. MTX treatment led to greater dominance of the health-associated phylum Proteobacteria. In the gut microbiome, AIA induction resulted in increased abundance of the Verrucomicrobiota phylum, and MTX treatment restored its levels compared to control. Importantly, the MTX-treated AIA animals had significantly less periodontal bone loss, as well as decreased hyperalgesia and joint oedema compared to the AIA animals.

CONCLUSION

Data suggest the benefit of MTX treatment in protecting alveolar bone, in addition to providing new insights on the drug-microbiome interaction in the course of RA.

Application and pharmacological mechanism of methotrexate in rheumatoid arthritis

Methotrexate (MTX) has been used for the treatment of rheumatoid arthritis (RA) for about forty years and to date MTX remains the part of global standard of treatment for RA. The efficacy of MTX in RA is the result of multiple mechanisms of action. In order to summarize the possible pharmacological mechanisms of MTX in the treatment of RA, this review will elaborate on folate antagonism, promotion of adenosine accumulation, regulation of inflammatory signaling pathways, bone protection and maintenance of immune system function.

Immune-mediated alopecias and their mechanobiological aspects

Alopecia is a non-specific term for hair loss clinically diagnosed by the hair loss pattern and histological analysis of patient scalp biopsies. The immune-mediated alopecia subtypes, including alopecia areata, lichen planopilaris, frontal fibrosing alopecia, and central centrifugal cicatricial alopecia, are common, significant forms of alopecia subtypes. For example, alopecia areata is the most common autoimmune disease with a lifetime incidence of approximately 2% of the world's population. In this perspective, we discuss major results from studies of immune-mediated alopecia subtypes. These studies suggest the key event in disease onset as the collapse in immune privilege, which alters the hair follicle microenvironment, e.g., upregulation of major histocompatibility complex molecules and increase of cytokine production, and results in immune cell infiltration, inflammatory responses, and damage of hair follicles. We note that previous studies have established that the hair follicle has a complex mechanical microenvironment, which may regulate the function of not only tissue cells but also immune cell infiltrates. This suggests a potential for mechanobiology to contribute to alopecia research by adding new methods, new approaches, and new ways of thinking, which is missing in the existing literature. To fill this a gap in the alopecia research space, we develop a mechanobiological hypothesis that alterations in the hair follicle microenvironment, specifically in the mechanically responsive tissues and cells, partially due to loss of immune privilege, may be contributors to disease pathology. We further focus our discussion on the potential for applying mechanoimmunology to the study of T cell infiltrates in the hair follicle, as they are considered primary contributors to alopecia pathology. To establish the connection between the mechanoimmunological hypothesis and immune-mediated alopecia subtypes, we discuss what is known about the role of T cells in immune-mediated alopecia subtypes, using the most extensively studied AA as our model.

Biomarkers to Predict DMARDs Efficacy and Adverse Effect in Rheumatoid Arthritis

Rheumatoid arthritis (RA), one of the most common immune system diseases, mainly affects middle-aged and elderly individuals and has a serious impact on the quality of life of patients. Pain and disability caused by RA are significant symptoms negatively affecting patients, and they are especially seen when inappropriate treatment is administered. Effective therapeutic strategies have evolved over the past few decades, with many new disease-modifying antirheumatic drugs (DMARDs) being used in the clinic. Owing to the breakthrough in the treatment of RA, the symptoms of patients who could not be treated effectively in the past few years have been relieved. However, some patients complain about symptoms that have not been reported, implying that there are still some limitations in the RA treatment and evaluation system. In recent years, biomarkers, an effective means of diagnosing and evaluating the condition of patients with RA, have gradually been used in clinical practice to evaluate the therapeutic effect of RA, which is constantly being improved for accurate application of treatment in patients with RA. In this article, we summarize a series of biomarkers that may be helpful in evaluating the therapeutic effect and improving the efficiency of clinical treatment for RA. These efforts may also encourage researchers to devote more time and resources to the study and application of biomarkers, resulting in a new evaluation system that will reduce the inappropriate use of DMARDs, as well as patients’ physical pain and financial burden.

Erteng Tongbi Decoction ameliorates collagen-induced arthritis in mice via modulating T cell differentiation and cytokines balance

ETHNOPHARMACOLOGICAL RELEVANCE

Herbs have been commonly used for the treatment of rheumatoid arthritis (RA). It has been verified that Erteng Tongbi Decoction has good therapeutic effects on RA, while, relatively few studies on the relationship between its components and anti-rheumatoid efficacy were carried out.

AIM OF THE STUDY

To discuss the anti-RA effects of Erteng Tongbi Decoction on collagen-induced arthritis (CIA) in mice and the influence of T cell differentiation and cytokines balance.

MATERIALS AND METHODS

Separate researches on the two traditional Chinese medicines of the Erteng Tongbi Decoction were conducted. First, a murine peritoneal macrophage model was established, and then the cytokines levels and macrophage maturity were measured to select the best extraction solvent. Furthermore, ethanol extracts were partitioned successively with four kinds of solvents, and the anti-inflammatory parts were selected by the same vitro model. Subsequently, mice were arbitrarily divided into control, CIA model, positive control, effective parts alone or in combination. After 20 days of oral administration, the weight, hind paw volume, rheumatism index value, and the pathological changes were checked to assess the obvious level of arthritis. Furthermore, the levels of IL-6, TNF-α, IL-10, and IL-17A in serum and the balance of Th17/Treg and Th1/Th2 cells in spleen and mesenteric lymph nodes (MLN) was detected. Finally, the major active constituents were identified.

RESULTS

In vitro, the anti-inflammatory effects of ethanol extracts was much better than water extract. In addition, the effective parts of Celastrus orbiculatus Thunb. ethanol extract were petroleum ether parts and dichloromethane parts. The effective parts of Spatholobus suberectus Dunn. ethanol extracts was petroleum ether parts and ethyl acetate parts screened. In vivo, effective parts compatibility could inhibit the progression of inflammation by modulating T cell differentiation and cytokines balance. Constituent analysis revealed that effective parts contained sesquiterpenes alkaloids, phenolic acids, and flavanols.

CONCLUSIONS

Erteng Tongbi Decoction could notably ameliorate CIA mice by modulating T cell differentiation and cytokines balance and support its application in folk medicine.

proBDNF/p75NTR promotes rheumatoid arthritis and inflammatory response by activating proinflammatory cytokines

P75 pan-neurotrophin receptor (p75NTR) is an important receptor for the role of neurotrophins in survival and death of neurons during development and after nerve injury. Our previous research found that the precursor of brain-derived neurotrophic factor (proBDNF) regulates pain as an inflammatory mediator. The current understanding of the role of proBDNF/p75NTR signaling pathway in inflammatory arthritis pain and rheumatoid arthritis (RA) is unclear. We recruited 20 RA patients, 20 healthy donors (HDs), and 10 osteoarthritis (OA) patients. Hematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) of proBDNF and p75NTR in synovial membrane were performed and evaluated. We next examined the mRNA and protein expression of proBDNF/p75NTR signaling pathway in peripheral blood mononuclear cells (PBMCs) and synovial tissue. ELISA and flow cytometry were assessed between the blood of RA patients and HD. To induce RA, collagen-induced arthritis (CIA) were induced in mice. We found over-synovitis of RA synovial membrane compared to OA controls in histologic sections. P75NTR and sortilin mRNA, and proBDNF protein level were significantly increased in PBMCs of RA patients compared with the HD. Consistently, ELISA showed that p75NTR, sortilin, tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-10 (IL-10) levels in the serum of RA patients were increased compared with HD and p75NTR, sortilin were positively correlated with Disease Activity Score in 28 joints (DAS28). In addition, using flow cytometry we showed that the increased levels of proBDNF and p75NTR characterized in CD4⁺ and CD8⁺ T cells of RA patients were subsequently reversed with methotrexate (MTX) treatment. Furthermore, we found pathological changes, inflammatory pain, upregulation of the mRNA and protein expression of proBDNF/p75NTR signaling pathway, and upregulation of inflammatory cytokines in spinal cord using a well-established CIA mouse model. We showed intravenous treatment of recombinant p75ECD-Fc that biologically blocked all inflammatory responses and relieved inflammatory pain of animals with CIA. Our findings showed the involvement of proBDNF/p75NTR pathway in the RA inflammatory response and how blocking it with p75ECD-Fc may be a promising therapeutic treatment for RA.

The implication of adenosine receptor expression in prediction of methotrexate clinical response in Egyptian rheumatoid arthritis patients

Background

Adenosine signaling is now an accepted explanation for the therapeutic mechanism of Methotrexate (MTX) in rheumatoid arthritis (RA). Adenosine receptors categorized into four subclasses: adenosine A1 receptor (ADORA1), adenosine 2a receptor (ADORA2a), adenosine 2b receptor (ADORA2B), and adenosine 3 receptor (ADORA3). Our aim is to check the mRNA expression of two adenosine receptors; ADORA2a and ADORA3 in whole blood cell of RA patients and its relation in prediction of MTX clinical response in Egyptian patients.

Results

There was significant correlation between both ADORA2a and ADORA3 gene expression in RA patients as compared with healthy controls. The expression of ADORA2a and ADORA3 was increased in good and moderate response groups compared to no response group. There was significant correlation between both genes in mRNA expression before and after MTX treatment. Matrix metalloproteinase-3 (MMP3) concentration was significantly decreased after treatment in good and moderate response groups in comparison to non-responder group.

Conclusion

The inflammatory and clinical responses in RA patients which is demonstrated by DAS28 and suppression of MMP3 were regulated by ADORA2a and ADORA3. Their level of expression can predict MTX response and their agonists may offer a novel and effective therapeutic option for RA patients.

Toward Overcoming Treatment Failure in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disorder characterized by inflammation and bone erosion. The exact mechanism of RA is still unknown, but various immune cytokines, signaling pathways and effector cells are involved. Disease-modifying antirheumatic drugs (DMARDs) are commonly used in RA treatment and classified into different categories. Nevertheless, RA treatment is based on a "trial-and-error" approach, and a substantial proportion of patients show failed therapy for each DMARD. Over the past decades, great efforts have been made to overcome treatment failure, including identification of biomarkers, exploration of the reasons for loss of efficacy, development of sequential or combinational DMARDs strategies and approval of new DMARDs. Here, we summarize these efforts, which would provide valuable insights for accurate RA clinical medication. While gratifying, researchers realize that these efforts are still far from enough to recommend specific DMARDs for individual patients. Precision medicine is an emerging medical model that proposes a highly individualized and tailored approach for disease management. In this review, we also discuss the potential of precision medicine for overcoming RA treatment failure, with the introduction of various cutting-edge technologies and big data.

Pharmacomicrobiology of Methotrexate in Rheumatoid Arthritis: Gut Microbiome as Predictor of Therapeutic Response

Rheumatoid arthritis (RA) is a disabling autoimmune disease with invasive arthritis as the main manifestation and synovitis as the basic pathological change, which can cause progressive destruction of articular cartilage and bone, ultimately leading to joint deformity and loss of function. Since its introduction in the 1980s and its widespread use in the treatment of RA, low-dose methotrexate (MTX) therapy has dramatically changed the course and outcome of RA treatment. The clinical use of this drug will be more rational with a better understanding of the pharmacology, anti-inflammatory mechanisms of action and adverse reaction about it. At present, the current clinical status of newly diagnosed RA is that MTX is initiated first regardless of the patients’ suitability. But up to 50% of patients could not reach adequate clinical efficacy or have severe adverse events. Prior to drug initiation, a prognostic tool for treatment response is lacking, which is thought to be the most important cause of the situation. A growing body of studies have shown that differences in microbial metagenomes (including bacterial strains, genes, enzymes, proteins and/or metabolites) in the gastrointestinal tract of RA patients may at least partially determine their bioavailability and/or subsequent response to MTX. Based on this, some researchers established a random forest model to predict whether different RA patients (with different gut microbiome) would respond to MTX. Of course, MTX, in turn, alters the gut microbiome in a dose-dependent manner. The interaction between drugs and microorganisms is called pharmacomicrobiology. Then, the concept of precision medicine has been raised. In this view, we summarize the characteristics and anti-inflammatory mechanisms of MTX and highlight the interaction between gut microbiome and MTX aiming to find the optimal treatment for patients according to individual differences and discuss the application and prospect of precision medicine.

T regulatory cells as a potential therapeutic target in psychosis? Current challenges and future perspectives

Many studies have reported that patients with psychosis, even before drug treatment, have mildly raised levels of blood cytokines relative to healthy controls. In contrast, there is a remarkable scarcity of studies investigating the cellular basis of immune function and cytokine changes in psychosis. The few flow-cytometry studies have been limited to counting the proportion of the major classes of monocyte and lymphocytes without distinguishing their pro- and anti-inflammatory subsets. Moreover, most of the investigations are cross-sectional and conducted with patients on long-term medication. These features make it difficult to eliminate confounding of illness-related changes by lifestyle factors, disease duration, and long exposure to antipsychotics. This article focuses on regulatory T cells (Tregs), cornerstone immune cells that regulate innate and adaptive immune forces and neuro-immune interactions between astrocytes and microglia. Tregs are also implicated in cardio-metabolic disorders that are common comorbidities of psychosis. We have recently proposed that Tregs are hypofunctional ('h-Tregs') in psychosis driven by our clinical findings and other independent research. Our h-Treg-glial imbalance hypothesis offers a new account for the co-occurrence of systemic immune dysregulation and mechanisms of psychosis development. This article extends our recent review, the h-Treg hypothesis, to cover new discoveries on Treg-based therapies from pre-clinical findings and their clinical implications. We provide a detailed characterisation of Treg studies in psychosis, identifying important methodological limitations and perspectives for scientific innovation. The outcomes presented in this article reaffirms our proposed h-Treg state in psychosis and reveals emerging preclinical research suggesting the potential benefit of Treg-enhancing therapies. There is a clear need for longitudinal studies conducted with drug-naïve or minimally treated patients using more sophisticated techniques of flow-cytometry, CyTOF expression markers, and in vitro co-culture assays to formally test the suppressive capacity of Tregs. Investment in Treg research offers major potential benefits in targeting emerging immunomodulatory treatment modalities on person-specific immune dysregulations.

A review of liquid biopsy as a tool to assess epigenetic, cfDNA and miRNA variability as methotrexate response predictors in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a common autoimmune inflammatory disease affecting 0.5-1% of adults worldwide. Achieving long term remission or low disease activity is possible through early diagnosis, rapid initiation of disease modifying anti-rheumatic drugs (DMARDs) and implementation of a treat to target approach. Initial DMARD therapy usually involves methotrexate (MTX), either alone or in combination with other agents, however 40% of RA patients do not respond adequately, putting them at risk of disease progression and unnecessary exposure to MTX related adverse effects. Early predictors of MTX response would therefore enable a more personalized treatment strategy, ensuring timely access to MTX for those likely to respond and importantly, early initiation of alternative treatment for those in which MTX is unlikely to be efficacious. Predicting response to treatment will most likely require consideration of the clinical characteristics of the patient and interrogation of a number of factors including genetic, epigenetic, cell free DNA (cfDNA) and microRNA (miRNA), all of which can be investigated through blood derived liquid biopsies. This review will summarize the existing literature examining the use of epigenetic factors, cfDNA and miRNA as response predictors among RA patients treated with MTX.

Sepsis expands a CD39+ plasmablast population that promotes immunosuppression via adenosine-mediated inhibition of macrophage antimicrobial activity

Sepsis results in elevated adenosine in circulation. Extracellular adenosine triggers immunosuppressive signaling via the A2a receptor (A2aR). Sepsis survivors develop persistent immunosuppression with increased risk of recurrent infections. We utilized the cecal ligation and puncture (CLP) model of sepsis and subsequent infection to assess the role of adenosine in post-sepsis immune suppression. A2aR-deficient mice showed improved resistance to post-sepsis infections. Sepsis expanded a subset of CD39^hi B cells and elevated extracellular adenosine, which was absent in mice lacking CD39-expressing B cells. Sepsis-surviving B cell-deficient mice were more resistant to secondary infections. Mechanistically, metabolic reprogramming of septic B cells increased production of ATP, which was converted into adenosine by CD39 on plasmablasts. Adenosine signaling via A2aR impaired macrophage bactericidal activity and enhanced interleukin-10 production. Septic individuals exhibited expanded CD39^hi plasmablasts and adenosine accumulation. Our study reveals CD39^hi plasmablasts and adenosine as important drivers of sepsis-induced immunosuppression with relevance in human disease.

Activated, Pro-Inflammatory Th1, Th17, and Memory CD4+ T Cells and B Cells Are Involved in Delayed-Type Hypersensitivity Arthritis (DTHA) Inflammation and Paw Swelling in Mice

Delayed-type hypersensitivity arthritis (DTHA) is a recently established experimental model of rheumatoid arthritis (RA) in mice with pharmacological values. Despite an indispensable role of CD4+ T cells in inducing DTHA, a potential role for CD4+ T cell subsets is lacking. Here we have quantified CD4+ subsets during DTHA development and found that levels of activated, pro-inflammatory Th1, Th17, and memory CD4+ T cells in draining lymph nodes were increased with differential dynamic patterns after DTHA induction. Moreover, according to B-cell depletion experiments, it has been suggested that this cell type is not involved in DTHA. We show that DTHA is associated with increased levels of B cells in draining lymph nodes accompanied by increased levels of circulating IgG. Finally, using the anti-rheumatoid agents, methotrexate (MTX) and the anti-inflammatory drug dexamethasone (DEX), we show that MTX and DEX differentially suppressed DTHA-induced paw swelling and inflammation. The effects of MTX and DEX coincided with differential regulation of levels of Th1, Th17, and memory T cells as well as B cells. Our results implicate Th1, Th17, and memory T cells, together with activated B cells, to be involved and required for DTHA-induced paw swelling and inflammation.

Surface AMP deaminase 2 as a novel regulator modifying extracellular adenine nucleotide metabolism

Adenine nucleotides represent crucial immunomodulators in the extracellular environment. The ectonucleotidases CD39 and CD73 are responsible for the sequential catabolism of ATP to adenosine via AMP, thus promoting an anti-inflammatory milieu induced by the "adenosine halo". AMPD2 intracellularly mediates AMP deamination to IMP, thereby both enhancing the degradation of inflammatory ATP and reducing the formation of anti-inflammatory adenosine. Here, we show that this enzyme is expressed on the surface of human immune cells and its predominance may modify inflammatory states by altering the extracellular milieu. Surface AMPD2 (eAMPD2) expression on monocytes was verified by immunoblot, surface biotinylation, mass spectrometry, and immunofluorescence microscopy. Flow cytometry revealed enhanced monocytic eAMPD2 expression after TLR stimulation. PBMCs from patients with rheumatoid arthritis displayed significantly higher levels of eAMPD2 expression compared with healthy controls. Furthermore, the product of AMPD2-IMP-exerted anti-inflammatory effects, while the levels of extracellular adenosine were not impaired by an increased eAMPD2 expression. In summary, our study identifies eAMPD2 as a novel regulator of the extracellular ATP-adenosine balance adding to the immunomodulatory CD39-CD73 system.

Cross-Tissue Transcriptomic Analysis Leveraging Machine Learning Approaches Identifies New Biomarkers for Rheumatoid Arthritis

There is an urgent need to identify biomarkers for diagnosis and disease activity monitoring in rheumatoid arthritis (RA). We leveraged publicly available microarray gene expression data in the NCBI GEO database for whole blood (N=1,885) and synovial (N=284) tissues from RA patients and healthy controls. We developed a robust machine learning feature selection pipeline with validation on five independent datasets culminating in 13 genes: TNFAIP6, S100A8, TNFSF10, DRAM1, LY96, QPCT, KYNU, ENTPD1, CLIC1, ATP6V0E1, HSP90AB1, NCL and CIRBP which define the RA score and demonstrate its clinical utility: the score tracks the disease activity DAS28 (p = 7e-9), distinguishes osteoarthritis (OA) from RA (OR 0.57, p = 8e-10) and polyJIA from healthy controls (OR 1.15, p = 2e-4) and monitors treatment effect in RA (p = 2e-4). Finally, the immunoblotting analysis of six proteins on an independent cohort confirmed two proteins, TNFAIP6/TSG6 and HSP90AB1/HSP90.

The Pretreatment Gut Microbiome Is Associated With Lack of Response to Methotrexate in New-Onset Rheumatoid Arthritis

OBJECTIVE

Although oral methotrexate (MTX) remains the anchor drug for rheumatoid arthritis (RA), up to 50% of patients do not achieve a clinically adequate outcome. In addition, there is a lack of prognostic tools for treatment response prior to drug initiation. This study was undertaken to investigate whether interindividual differences in the human gut microbiome can aid in the prediction of MTX efficacy in new-onset RA.

METHODS

We performed 16S ribosomal RNA gene and shotgun metagenomic sequencing on the baseline gut microbiomes of drug-naive patients with new-onset RA (n = 26). Results were validated in an additional independent cohort (n = 21). To gain insight into potential microbial mechanisms, we conducted ex vivo experiments coupled with metabolomics analysis to evaluate the association between microbiome-driven MTX depletion and clinical response.

RESULTS

Our analysis revealed significant associations of the abundance of gut bacterial taxa and their genes with future clinical response (q < 0.05), including orthologs related to purine and MTX metabolism. Machine learning techniques were applied to the metagenomic data, resulting in a microbiome-based model that predicted lack of response to MTX in an independent group of patients. Finally, MTX levels remaining after ex vivo incubation with distal gut samples from pretreatment RA patients significantly correlated with the magnitude of future clinical response, suggesting a possible direct effect of the gut microbiome on MTX metabolism and treatment outcomes.

CONCLUSION

Taken together, these findings are the first step toward predicting lack of response to oral MTX in patients with new-onset RA and support the value of the gut microbiome as a possible prognostic tool and as a potential target in RA therapeutics.

Transcriptome-wide study of TNF-inhibitor therapy in rheumatoid arthritis reveals early signature of successful treatment

BACKGROUND

Despite the success of TNF-inhibitor therapy in rheumatoid arthritis treatment, up to 40% of patients fail to respond adequately. This study aimed to identify transcriptome-based biomarkers of adalimumab response in rheumatoid arthritis (RA) to aid timely switching in non-responder patients and provide a better mechanistic understanding of the pathways involved in response/non-response.

METHODS

The Affymetrix Human Transcriptome Array 2.0 (HTA) was used to measure the transcriptome in whole blood at pre-treatment and at 3 months in EULAR good- and non-responders to adalimumab therapy. Differential expression of transcripts was analysed at the transcript level using multiple linear regression. Differentially expressed genes were validated in independent samples using OpenArray™ RT-qPCR.

RESULTS

In total, 813 transcripts were differentially expressed between pre-treatment and 3 months in adalimumab good-responders. No significant differential expression was observed between good- and non-responders at either time-point and no significant changes were observed in non-responders between time-points. OpenArray™ RT-qPCR was performed for 104 differentially expressed transcripts in good-responders, selected based on magnitude of effect or p value or based on prior association with RA or the immune system, validating differential expression for 17 transcripts.

CONCLUSIONS

An early transcriptome signature of DAS28 response to adalimumab has been identified and replicated in independent datasets. Whilst treat-to-target approaches encourage early switching in non-responsive patients, registry evidence suggests that this does not always occur. The results herein could guide the development of a blood test to distinguish responders from non-responders at 3 months and support clinical decisions to switch non-responsive patients to an alternative therapy.

Impaired regulatory T cell control of astroglial overdrive and microglial pruning in schizophrenia

It is widely held that schizophrenia involves an active process of peripheral inflammation that induces or reflects brain inflammation with activation of microglia, the brain's resident immune cells. However, recent in vivo radioligand binding studies and large-scale transcriptomics in post-mortem brain report reduced markers of microglial inflammation. The findings suggest a contrary hypothesis; that microglia are diverted into their non-inflammatory synaptic remodelling phenotype that interferes with neurodevelopment and perhaps contributes to the relapsing nature of schizophrenia. Recent discoveries on the regulatory interactions between micro- and astroglial cells and immune regulatory T cells (Tregs) cohere with clinical omics data to suggest that: i) disinhibited astrocytes mediate the shift in microglial phenotype via the production of transforming growth factor-beta, which also contributes to the disturbances of dopamine and GABA function in schizophrenia, and ii) systemically impaired functioning of Treg cells contributes to the dysregulation of glial function, the low-grade peripheral inflammation, and the hitherto unexplained predisposition to auto-immunity and reduced life-expectancy in schizophrenia, including greater COVID-19 mortality.

Regulatory T cells in autoimmune hepatitis: an updated overview

Regulatory T-cells (Tregs) are key players in the maintenance of immune homeostasis by preventing immune responses to self-antigens. Defects in Treg frequency and/or function result in overwhelming CD4 and CD8 T cell immune responses participating in the autoimmune attack. Perpetuation of autoimmune damage is also favored by Treg predisposition to acquire effector cell features upon exposure to a proinflammatory challenge. Treg impairment plays a permissive role in the initiation and perpetuation of autoimmune liver diseases, namely autoimmune hepatitis, primary biliary cholangitis and primary sclerosing cholangitis. In this Review, we outline studies reporting the role of Treg impairment in the pathogenesis of these conditions and discuss methods to restore Treg number and function either by generation/expansion in the test tube or through in vivo expansion upon administration of low dose IL-2. Challenges and caveats of these potential therapeutic strategies are also reviewed and discussed.

Ectonucleotidases in Acute and Chronic Inflammation

Ectonucleotidases are extracellular enzymes with a pivotal role in inflammation that hydrolyse extracellular purine and pyrimidine nucleotides, e.g., ATP, UTP, ADP, UDP, AMP and NAD⁺. Ectonucleotidases, expressed by virtually all cell types, immune cells included, either as plasma membrane-associated or secreted enzymes, are classified into four main families: 1) nucleoside triphosphate diphosphohydrolases (NTPDases), 2) nicotinamide adenine dinucleotide glycohydrolase (NAD glycohydrolase/ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase 1), 3) ecto-5′-nucleotidase (NT5E), and 4) ecto-nucleotide pyrophosphatase/phosphodiesterases (NPPs). Concentration of ATP, UTP and NAD⁺ can be increased in the extracellular space thanks to un-regulated, e.g., cell damage or cell death, or regulated processes. Regulated processes include secretory exocytosis, connexin or pannexin hemichannels, ATP binding cassette (ABC) transporters, calcium homeostasis modulator (CALMH) channels, the ATP-gated P2X7 receptor, maxi-anion channels (MACs) and volume regulated ion channels (VRACs). Hydrolysis of extracellular purine nucleotides generates adenosine, an important immunosuppressant. Extracellular nucleotides and nucleosides initiate or dampen inflammation via P2 and P1 receptors, respectively. All these agents, depending on their level of expression or activation and on the agonist concentration, are potent modulators of inflammation and key promoters of host defences, immune cells activation, pathogen clearance, tissue repair and regeneration. Thus, their knowledge is of great importance for a full understanding of the pathophysiology of acute and chronic inflammatory diseases. A selection of these pathologies will be briefly discussed here.

Ectonucleotidase Modulation of Lymphocyte Function in Gut and Liver

Imbalance between regulatory and effector T lymphocytes contributes to loss of immunotolerance and plays a permissive role in the initiation, perpetuation, and progression of chronic inflammatory diseases and autoimmune disorders. Regulatory/effector cell balance is governed by the CD39 ectonucleotidase, the prototype member of the NTPDase family that hydrolyzes ATP and ADP into AMP, subsequently converted into adenosine by CD73. Generation of adenosine impacts T-cell function as it contributes to the mechanism of suppression of Tregs and confers regulatory properties to pathogenic Th17-cells. CD39 cell distribution, mechanism of regulation and impact on inflammatory and regulatory signaling pathways are also discussed here. Innovative therapeutic strategies to boost CD39 levels and activity by either administering soluble ADPases or interfering with CD39 inhibitory signals are reviewed. Restoration of CD39 levels and function has enormous translational and clinical implications and should be regarded as an additional form of treatment to be deployed in the chronic inflammatory setting. The key role of CD39 in immunoregulation in the context of Crohn's disease, one of the most frequent manifestations of inflammatory bowel disease, and autoimmune hepatitis, an autoimmune disorder of the liver, is reviewed and discussed here.

AHR-dependent genes and response to MTX therapy in rheumatoid arthritis patients

Methotrexate (MTX) is the first-line therapy for rheumatoid arthritis. Nevertheless, MTX resistance is quite a common issue in clinical practice. There are some premises that aryl hydrocarbon receptor (AhR) gene battery may take part in MTX metabolism. In the present retrospective study, we analyzed genes expression of AHR genes battery associated with MTX metabolism in whole blood of RA patients with good and poor response to MTX treatment. Additionally, sequencing, genotyping and bioinformatics analysis of AHR repressor gene (AHRR) c.565C > G (rs2292596) and c.1933G > C (rs34453673) have been performed. Theoretically, both changes may have an impact on H3K36me3 and H3K27me3. Evolutionary analysis revealed that rs2292596 may be possibly damaging. Allele G in rs2292596 and DAS28 seems to be associated with a higher risk of poor response to MTX treatment in RA. RA patients with poor response to MTX treatment revealed upregulated AhR and SLC19A1 mRNA level. Treatment with IL-6 inhibitor may be helpful to overcome the low-dose MTX resistance. Analysis of gene expression revealed possible another cause of poor response to MTX treatment which is different from that observed in the case of acute lymphoblastic leukemia.

Identification of Metabolic Biomarkers in Relation to Methotrexate Response in Early Rheumatoid Arthritis

This study aimed to identify baseline metabolic biomarkers for response to methotrexate (MTX) therapy in rheumatoid arthritis (RA) using an untargeted method. In total, 82 baseline plasma samples (41 insufficient responders and 41 sufficient responders to MTX) were selected from the Treatment in the Rotterdam Early Arthritis Cohort (tREACH, trial number: ISRCTN26791028) based on patients' EULAR response at 3 months. Metabolites were assessed using high-performance liquid chromatography-quadrupole time of flight mass spectrometry. Differences in metabolite concentrations between insufficient and sufficient responders were assessed using partial least square regression discriminant analysis (PLS-DA) and Welch's t-test. The predictive performance of the most significant findings was assessed in a receiver operating characteristic plot with area under the curve (AUC), sensitivity and specificity. Finally, overrepresentation analysis was performed to assess if the best discriminating metabolites were enriched in specific metabolic events. Baseline concentrations of homocystine, taurine, adenosine triphosphate, guanosine diphosphate and uric acid were significantly lower in plasma of insufficient responders versus sufficient responders, while glycolytic intermediates 1,3-/2,3-diphosphoglyceric acid, glycerol-3-phosphate and phosphoenolpyruvate were significantly higher in insufficient responders. Homocystine, glycerol-3-phosphate and 1,3-/2,3-diphosphoglyceric acid were independent predictors and together showed a high AUC of 0.81 (95% CI: 0.72-0.91) for the prediction of insufficient response, with corresponding sensitivity of 0.78 and specificity of 0.76. The Warburg effect, glycolysis and amino acid metabolism were identified as underlying metabolic events playing a role in clinical response to MTX in early RA. New metabolites and potential underlying metabolic events correlating with MTX response in early RA were identified, which warrant validation in external cohorts.

A randomised clinical trial of methotrexate points to possible efficacy and adaptive immune dysfunction in psychosis

NMDA autoantibody encephalitis presenting as schizophrenia suggests the possible role of adaptive cell-mediated immunity in idiopathic schizophrenia. However, to our knowledge there have been no trials of the immune-suppressant methotrexate in schizophrenia. We tested if low-dose methotrexate as used in the treatment of systemic autoimmune disorders would be tolerable and effective in people with schizophrenia in a feasibility study. Ninety-two participants within 5 years of schizophrenia diagnosis were recruited from inpatient and outpatient facilities in Karachi, Pakistan. They were randomised to receive once weekly 10-mg oral methotrexate (n = 45) or matching placebo (n = 47) both with daily 5-mg folic acid, in addition to treatment as usual for 12 weeks. There were eight dropouts per group. Side effects were non-significantly more common in those on methotrexate and were not severe. One person developed leukopenia. Positive symptom scores improved more in those receiving methotrexate than placebo (β = -2.5; [95% CI -4.7 to -0.4]), whereas negative symptoms were unaffected by treatment (β = -0.39; [95% CI -2.01 to 1.23]). There were no immune biomarkers but methotrexate did not affect group mean leucocyte counts or C-reactive protein. We conclude that further studies are feasible but should be focussed on subgroups identified by advances in neuroimmune profiling. Methotrexate is thought to work in autoimmune disorders by resetting systemic regulatory T-cell control of immune signalling; we show that a similar action in the CNS would account for otherwise puzzling features of the immuno-pathogenesis of schizophrenia.

Blood pro-resolving mediators are linked with synovial pathology and are predictive of DMARD responsiveness in rheumatoid arthritis

Biomarkers are needed for predicting the effectiveness of disease modifying antirheumatic drugs (DMARDs). Here, using functional lipid mediator profiling and deeply phenotyped patients with early rheumatoid arthritis (RA), we observe that peripheral blood  specialized pro-resolving mediator (SPM) concentrations are linked with both DMARD responsiveness and disease pathotype. Machine learning analysis demonstrates that baseline plasma concentrations of resolvin D4, 10S, 17S-dihydroxy-docosapentaenoic acid, 15R-Lipoxin (LX)A4 and n-3 docosapentaenoic-derived Maresin 1 are predictive of DMARD responsiveness at 6 months. Assessment of circulating SPM concentrations 6-months after treatment initiation establishes that differences between responders and non-responders are maintained, with a decrease in SPM concentrations in patients resistant to DMARD therapy. These findings elucidate the potential utility of  plasma SPM concentrations as biomarkers of DMARD responsiveness in RA.

B cells from Patients with Rheumatoid Arthritis Show Conserved CD39-Mediated Regulatory Function and increased CD39 Expression After Positive Response to Therapy

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by progressive joint destruction associated with increased pro-inflammatory mediators. In inflammatory microenvironments, exogenous ATP (eATP) is hydrolyzed to adenosine, which exerts immunosuppressive effects, by the consecutive action of the ectonucleotidases CD39 and CD73. Mature B cells constitutively express both ectonucleotidases, converting these cells to potential suppressors. Here, we assessed CD39 and CD73 expression on B cells from treated or untreated patients with RA. Neither the frequency of CD73⁺CD39⁺ and CD73^-CD39⁺ B cell subsets nor the levels of CD73 and CD39 expression on B cells from untreated or treated RA patients showed significant changes in comparison to healthy controls (HC). CpG+IL-2-stimulated B cells from HC or untreated RA patients increased their CD39 expression, and suppressed CD4⁺ and CD8⁺ T cell proliferation and intracellular TNF-production. A CD39 inhibitor significantly restored proliferation and TNF-producing capacity in CD4⁺ T cells, but not in CD8⁺ T cells, from HC and untreated RA patients, indicating that B cells from untreated RA patients conserved CD39-mediated regulatory function. Good responder patients to therapy (R-RA) exhibited an increased CD39 but not CD73 expression on B cells after treatment, while most of the non-responder (NR) patients showed a reduction in ectoenzyme expression. The positive changes of CD39 expression on B cells exhibited a negative correlation with disease activity and rheumatoid factor levels. Our results suggest modulating the ectoenzymes/ADO pathway as a potential therapy target for improving the course of RA.

Adenosine Signaling in Autoimmune Disorders

The molecular components of the purinergic system (i.e., receptors, metabolizing enzymes and membrane transporters) are widely expressed in the cells of the immune system. Additionally, high concentrations of adenosine are generated from the hydrolysis of ATP in any "danger" condition, when oxygen and energy availability dramatically drops. Therefore, adenosine acts as a retaliatory metabolite to counteract the nucleotide-mediated boost of the immune reaction. Based on this observation, it can be foreseen that the recruitment with selective agonists of the receptors involved in the immunomodulatory effect of adenosine might represent an innovative anti-inflammatory approach with potential exploitation in autoimmune disorders. Quite surprisingly, pro-inflammatory activity exerted by some adenosine receptors has been also identified, thus paving the way for the hypothesis that at least some autoimmune disorders may be caused by a derailment of adenosine signaling. In this review article, we provide a general overview of the roles played by adenosine on immune cells with a specific focus on the development of adenosine-based therapies for autoimmune disorders, as demonstrated by the exciting data from concluded and ongoing clinical trials.

Higher Frequency and Increased Expression of Molecules Associated with Suppression on T Regulatory Cells from Newborn Compared with Adult Nonhuman Primates

T regulatory cells (Tregs) play a critical role in controlling the immune response, often limiting pathogen-specific cells to curb immune-mediated damage. Studies in human infants have reported an increased representation of Tregs in these individuals. However, how these cells differ from those in adults at various sites and how they respond to activation signals is relatively unknown. In this study, we used a newborn nonhuman primate model to assess Treg populations present at multiple sites with regard to frequency and phenotype in comparison with those present in adult animals. We found that Foxp3⁺ cells were more highly represented in the T cell compartment of newborn nonhuman primates for all sites examined (i.e., the spleen, lung, and circulation). In the spleen and circulation, newborn-derived Tregs expressed significantly higher levels of Foxp3 and CD25 compared with adults, consistent with an effector phenotype. Strikingly, the phenotype of Tregs in the lungs of adult and infant animals was relatively similar, with both adult and newborn Tregs exhibiting a more uniform PD-1⁺CD39⁺ phenotype. Finally, in vitro, newborn Tregs exhibited an increased requirement for TCR engagement for survival. Further, these cells upregulated CD39 more robustly than their adult counterpart. Together, these data provide new insights into the quantity of Tregs in newborns, their activation state, and their potential to respond to activation signals.

Association of a Type 2-Polarized T Cell Phenotype With Methotrexate Nonresponse in Patients With Rheumatoid Arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is a chronic inflammatory disease mediated through complex immunologic pathways. Among RA patients receiving low-dose methotrexate (MTX) monotherapy, approximately one-half exhibit a meaningful clinical response within the first 6 months of starting treatment. Whether baseline immune phenotypes differ between subsequent MTX responders and nonresponders is unknown. This study utilized comprehensive T cell immunophenotyping to identify specific immunologic pathways associated with MTX-nonresponsive joint inflammation in patients with RA.

METHODS

In total, 32 patients with recent-onset RA were treated with MTX therapy. After 6 months, 15 patients were categorized as responders and 17 as nonresponders. Comprehensive blood T cell immunophenotyping, using multiparameter immunofluorescence flow cytometry analyses, was performed at baseline and following 6 months of treatment.

RESULTS

Baseline measures of disease activity (Disease Activity Score in 28 joints [DAS28], C-reactive protein level, and erythrocyte sedimentation rate) did not differ between MTX responders and nonresponders following MTX treatment. Frequencies of CD4+ and CD8+ T cells were skewed to favor higher CD4:CD8 T cell ratios in MTX responders compared to nonresponders (P < 0.05). The proportion of inducible costimulator-expressing Treg cells was significantly greater among MTX nonresponders. Interleukin-13 (IL-13)-producing, but not interferon-γ- or IL-17-producing, CD4+ effector memory T (Tem) cells were significantly more frequent in MTX nonresponders (P < 0.05). The ratio of IL-13+:IL-17+ Tem cells among CD4+ Tem cells was 1.9-fold higher in MTX nonresponders compared to responders (P < 0.05). Both the CD4:CD8 T cell ratio and the frequency of IL-13+CD4+ Tem cells correlated with changes in the DAS28 score following MTX treatment, whereas T cell expression of immune checkpoint inhibitor markers (CTLA-4, programmed death 1, and T cell immunoglobulin and mucin domain-containing protein 3) did not differ between MTX responders and nonresponders.

CONCLUSION

We observed a bias toward type 2-polarized T cell inflammatory responses in the peripheral blood of MTX-nonresponsive RA patients. Targeting the IL-13+CD4+ T cell pathway could be a new therapeutic strategy in RA patients whose disease remains resistant to MTX.

Soluble epoxide hydrolase inhibitor, TPPU, increases regulatory T cells pathway in an arthritis model

Epoxyeicosatrienoic acids (EET) and related epoxy fatty acids (EpFA) are endogenous anti‐inflammatory compounds, which are converted by the soluble epoxide hydrolase (sEH) to dihydroxylethersatrienoic acids (DHETs) with lessened biological effects. Inhibition of sEH is used as a strategy to increase EET levels leading to lower inflammation. Rheumatoid arthritis is a chronic autoimmune disease that leads to destruction of joint tissues. This pathogenesis involves a complex interplay between the immune system, and environmental factors. Here, we investigate the effects of inhibiting sEH with 1‐trifluoromethoxyphenyl‐3‐(1‐propionylpiperidin‐4‐yl) urea (TPPU) on a collagen‐induced arthritis model. The treatment with TPPU ameliorates hyperalgesia, edema, and decreases the expression of important pro‐inflammatory cytokines of Th1 and Th17 profiles, while increasing Treg cells. Considering the challenges to control RA, this study provides robust data supporting that inhibition of the sEH is a promising target to treat arthritis.

Regulatory T cells in patients with early untreated rheumatoid arthritis: Phenotypic changes in the course of methotrexate treatment

Rheumatoid arthritis (RA) is frequent systemic autoimmune disease characterized by excessive activation of collagen-specific T helper cells, and elevated level of autoantibodies in the serum. Development of RA is associated with defect in compartment of regulatory CD4+Foxp3+ T cells (Treg), but data concerning suppressive potential of Treg population in RA patients are contradictory and depend on the stage of disease. In this study we aimed to characterize abundance and phenotypic markers of CD4+Foxp3+ Treg in peripheral blood of healthy donors compared to untreated early RA patients to find potential correlations with the disease activity, antibody level, and absolute numbers and proportion of different subpopulations of T cells. Moreover, we assessed the influence of methotrexate (MT) treatment on percentage and absolute numbers of CD4+Foxp3+ Treg from the peripheral blood of untreated early RA patients. We demonstrate that increase and phenotypic changes in Treg population correlate well with response to MT. Analysis of the cohorts of matched RA patients (n = 45) and healthy controls (n = 20) revealed that patients with untreated early RA demonstrate substantial decrease in blood Treg percentage and absolute number, as well as low level of activated Treg surface markers in comparison to healthy control. The defect in Treg compartment negatively correlates with both RA activity and antibody level. MT treatment of patients with early untreated RA increases both proportion and absolute number of Treg with high level of activation markers, suggesting an increase of their functional capacity. Here we speculate the role of Tregs as specific cellular marker of successful RA treatment.

ROS-Responsive Berberine Polymeric Micelles Effectively Suppressed the Inflammation of Rheumatoid Arthritis by Targeting Mitochondria

Rheumatoid arthritis (RA) is an autoimmune disease, which attacks human joint system and causes lifelong inflammatory condition. To date, no cure is available for RA and even the ratio of achieving remission is very low. Hence, to enhance the efficacy of RA treatment, it is essential to develop novel approaches specifically targeting pathological tissues. In this study, we discovered that RA synovial fibroblasts exhibited higher reactive oxygen species (ROS) and mitochondrial superoxide level, which were adopted to develop ROS-responsive nano-medicines in inflammatory microenvironment for enhanced RA treatment. A selenocystamine-based polymer was synthesized as a ROS-responsive carrier nanoplatform, and berberine serves as a tool drug. By assembling, ROS-responsive berberine polymeric micelles were fabricated, which remarkably increased the uptake of berberine in RA fibroblast and improved in vitro and in vivo efficacy ten times higher. Mechanistically, the anti-RA effect of micelles was blocked by the co-treatment of AMPK inhibitor or palmitic acid, indicating that the mechanism of micelles was carried out through targeting mitochondrial, suppressing lipogenesis and finally inhibiting cellular proliferation. Taken together, our ROS-responsive nano-medicines represent an effective way of preferentially releasing prodrug at the inflammatory microenvironment and improving RA therapeutic efficacy.

Synergistic Effects of Erzhi Pill Combined With Methotrexate on Osteoblasts Mediated via the Wnt1/LRP5/β-Catenin Signaling Pathway in Collagen-Induced Arthritis Rats

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by chronic synovitis, bone erosion, and bone loss. Erzhi Pill (EZP), a classic Chinese patent medicine, is often used to treat osteoporosis and shows a capacity for bone metabolism regulation. Methotrexate (MTX), an essential drug for RA treatment, has been reported to inhibit generalized bone loss in RA patients. However, the combined therapeutic effects and mechanism of EZP and MTX in RA have not been fully elucidated. The aim of this study was to investigate the synergistic effect of EZP and MTX on RA and to explore the underlying mechanism through network pharmacological prediction and experimental verification. Chemical compounds of EZP, human target proteins of EZP and MTX, and RA-related human genes were identified in the Encyclopedia of Traditional Chinese Medicine database, PubChem database, and NCBI database, respectively. The molecular network of EZP and MTX in RA was generated and analyzed with Ingenuity Pathway Analysis software according to the datasets. Then, MTX monotherapy, EZP monotherapy, and combined MTX and EZP therapy were administered to collagen-induced arthritis rats, followed by assessment of pathological score, bone damage, bone alkaline phosphatases (BALP), and tartrate-resistant acid phosphatase (TRACP), and of gene levels related to the Wnt1/LRP5/β-catenin pathway according to network pharmacological analysis. Finally, serum samples from MTX-, EZP- and MTX+EZP-treated rats were used to treat the rat osteoblast (OB)-like UMR-106 cell line to evaluate gene levels related to Wnt1/LRP5/β-catenin. Network pharmacological analysis showed that the Wnt/β-catenin signaling pathway was the top signaling pathway shared among MTX, EZP, and RA. The results from in vivo experiments indicated that EZP combined with MTX reduced arthritis severity, alleviated ankle bone damage, increased BALP and decreased TRACP serum levels, and regulated the mRNA expression of Wnt1, LRP5, β-catenin, Runx2, BALP, and BGP in the ankles. In vitro experiments showed that EZP combined with MTX could also improve the expression of genes related to the Wnt1/LRP5/β-catenin pathway. This study demonstrated that EZP in combination with MTX played a synergistic role in regulating OBs in RA, which was connected to the modulatory effect of EZP and MTX on the Wnt1/LRP5/β-catenin signaling pathway.

Discriminative expression of CD39 and CD73 in Cerebrospinal fluid of patients with Multiple Sclerosis and Neuro-Behçet's disease

Treg-mediated immune suppression involves many molecular mechanisms including the cleavage of inflammatory extracellular ATP to adenosine by CD39 ectoenzyme. In the peripheral blood of Multiple Sclerosis (MS) patients, it has been suggested that CD39+ Treg cells have the potential to suppress pro-inflammatory IL-17 secreting cells. Herein, we studied cellular phenotype and mRNA expression of CD39 and CD73 ectoenzymes in the Cerebrospinal fluid (CSF) of MS patients and another neuro-inflammatory disease: the Neuro-behçet's disease (NBD). Using qRT-PCR, we assessed mRNA expression of CD39 and CD73 as well as anti-inflammatory (IL-10) and pro-inflammatory (IL-6, TNF-α, IL-1β) cytokines in patients Peripheral blood mononuclear cells (PBMCs) and CSF of 28 relapsing-remitting multiple sclerosis (RRMS), 20 NBD and 22 controls with non inflammatory neurological disorders (NIND). The most substantial result in the CSF was the higher expression of CD39 in both RRMS and NBD patients compared to NIND. While, the expression of CD73 in CSF samples of NBD was low. In RRMS samples, we detected a significant positive correlation of both CD39 and CD73 with IL-10 expression. Moreover, results by flow cytometry revealed a high percentage of CD39 Treg cells in RRMS CSF. CD39 was preferentially expressed on B cells of NBD. Regarding inflammatory response, we showed a significant increase of IL-6 mRNA expression in NBD patients CSF while in RRMS this increase concerned TNF-α. These results bring evidence that CD39 correlates positively with an anti-inflammatory IL-10 response in RRMS. In contrast, no such association was observed in CSF of NBD patients and CD39 was preferentially expressed on B cells.