The role of interleukin-17 in the pathogenesis of rheumatoid arthritis

A synergistic effect of triptolide and curcumin on rheumatoid arthritis by improving cell proliferation and inducing cell apoptosis via inhibition of the IL-17/NF-κB signaling pathway

Rheumatoid arthritis (RA) is a chronic, progressive, systemic autoimmune disease. While triptolide (TPL) and curcumin (CUR) are known to have multiple beneficial effects on RA, the combined effect of TPL and CUR remains unexplored. This study aimed to investigate their synergistic effect on cell proliferation and apoptosis via the IL-17/NF-κB signaling pathway. The collagen-induced arthritis (CIA) rat model was established, showing severe joint and synovial damage compared to normal rats. Treatment with TPL and CUR reduced the severity of RA in the CIA rat model and alleviated serum inflammatory cytokines, such as rheumatoid factor, IL-17, TNF-α, IL-1β, and IL-6. The elevated levels of IL-17 and NF-κB in CIA rats were also inhibited, and the resistant apoptosis was aggravated by TPL and CUR. In vitro, the improvement of cell proliferation and induction of apoptosis were observed in LPS-stimulated MH7A cells treated with TPL and CUR, associated with the inhibition of the IL-17/NF-κB signaling pathway. Taken together, a synergistic effect of TPL and CUR on RA may involve relieving symptoms, improving excessive proliferation, inducing apoptosis resistance, and inhibiting the IL-17/NF-κB signaling pathway.

Discovery and In Vivo Exploration of 1,3,4-Oxadiazole and α-Fluoroacrylate Containing IL-17 Inhibitors

IL-17, a pro-inflammatory cytokine produced mainly by Th17 cells, is involved in the immune response to fungal and bacterial infections, whereas its aberrant production is associated with autoimmune and inflammatory diseases. IL-17 blocking antibodies like secukinumab (Cosentyx) have been developed and are used to treat conditions like psoriasis, psoriatic arthritis, and ankylosing spondylitis. Recently, the low molecular weight IL-17 inhibitor LY3509754 entered the clinic but was discontinued in Phase 1 due to adverse effects. In this study, we explored the replacements of furazan moiety posing a potential toxicology risk in LY3509754. By exploring replacements such as heterocycles as amide-isosteres as well as α-F-acrylamides, two compounds (18 and 26) were identified. Both compounds effectively reduced knee swelling in a rat arthritis model. However, early rat and dog toxicity studies revealed adverse findings, preventing their further development and indicating that furazan might not be responsible for the adverse effects of LY3509754.

Role of Interleukin-17 in Predicting Activity of Rheumatoid Arthritis and Systemic Lupus Erythematosus

Background

Although high serum levels of interleukin (IL)-17 and its producing cells have been found in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) in earlier research, it is still unclear how these findings relate to disease activity.

Objectives

This study examines the link between serum levels of IL-17 and the activity of both RA and SLE.

Design

This pilot case-control study included 100 patients with RA, 100 with SLE, and 100 healthy controls.

Methods

The Disease Activity Score-28 (DAS28) scores assessed the activity of RA, whereas the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) scores assessed SLE activity. All participants' data were compared and correlated.

Results

Serum levels of IL-17 were significantly higher in RA and SLE patients compared with the controls (P < .001) and showed significantly positive correlations (P < .001) with rheumatoid factor titer, anti-cyclic citrullinated peptide (anti-CCP) and DAS28 score among the RA patients. Although among SLE patients, they were significantly positively correlated (P < .001) with anti-double-stranded DNA (anti-ds DNA) levels and the SLEDAI-2K scores, the best cut-off value of IL-17 for predicting moderate and high disease activity was > 175 pg/mL among RA patients and > 95 pg/mL among SLE patients.

Conclusions

There is a significant correlation between RA and SLE activity and serum levels of IL-17. This discovery emphasizes IL-17 as a potential therapeutic target.

Tocilizumab provides dual benefits in treating immune checkpoint inhibitor-associated arthritis and preventing relapse during ICI rechallenge: the TAPIR study

BACKGROUND

The aim of this retrospective study was to evaluate the dual efficacy of tocilizumab (TCZ) in the treatment of immune checkpoint inhibitor (ICI)-associated arthritis (ICI-AR) and the prevention of relapses after rechallenge.

PATIENTS AND METHODS

We identified 26 patients with ICI-AR. The primary objectives were to evaluate TCZ efficacy in ICI-AR treatment and as secondary prophylaxis during ICI rechallenge in 11 of them. Patients received prednisone (CS) at 0.3 mg/kg tapered at 0.05 mg/kg weekly for six weeks. TCZ was administered at a dose of 8 mg/kg every 2 weeks. In the subgroup receiving secondary prophylaxis (rechallenge n = 11), TCZ was reintroduced with the same regimen concurrently with ICI rechallenge, and without the addition of CS. A control group of patients (rechallenge n = 5) was rechallenged without TCZ. Secondary endpoints included post-rechallenge evaluation of ICI duration, reintroduction of CS >0.1 mg/kg/day, ICI-AR flares, and disease control rate.

RESULTS

The median age of the patients was 70 years. The median follow-up from ICI initiation was 864 days. Among the 20 patients treated with TCZ for ICI-AR, all (100%) achieved an ACR70 response rate, defined as greater than 70% improvement, at 10 weeks. Some 81% of these patients achieved steroid-free remission after 24 weeks on TCZ. The median follow-up period was 552 days in rechallenged patients. The results demonstrated a reduction in ICI-AR relapses upon ICI rechallenge in patients receiving TCZ prophylaxis compared with patients who did not receive prophylaxis (17% versus 40%). The requirement for CS was completely abolished with prophylaxis (0% versus 20%), and the mean duration of ICI treatment was notably extended from 113 to 206 days. The 12-month post-rechallenge outcomes showed a disease control rate of 77%. During TCZ prophylaxis, CXCL9 remained elevated, showing no decline from their concentrations at the onset of ICI-AR.

CONCLUSIONS

In addition to treating ICI-AR, TCZ demonstrated efficacy as a secondary prophylactic agent, preventing the recurrence of symptoms and lengthening ICI treatment duration after ICI rechallenge.

A Comprehensive Flow Cytometry Panel for Analysis of Idiopathic Subglottic Stenosis

OBJECTIVE

To present a comprehensive flow cytometry panel for idiopathic subglottic stenosis (iSGS).

STUDY DESIGN

Controlled ex vivo cohort study.

SETTING

Tertiary care academic hospital in a metropolitan area.

METHODS

Flow cytometry and single-cell RNA sequencing were performed on 9 paired normal and scar tissue samples from iSGS patients. Flow cytometry was used to assess the presence of myeloid (CD11b, CD14, CD15, Siglec8), lymphoid (CD3, CD4, CD8, gamma delta [γδ], FOXP3), endothelial (CD31), fibroblast (CD90, SMA), and epithelial (CD326, CK5) markers.

RESULTS

On flow cytometry, iSGS scar is characterized by an increased presence of myeloid, lymphoid, endothelial, and fibroblast cell types, but a decreased presence of epithelial cells. In the myeloid lineage, iSGS scar samples demonstrated increased CD11b+ monocytes (P < .001), Siglec8+ eosinophils (P = .03), and CD14+ monocytes (P = .02). In the lymphoid lineage, iSGS scar demonstrated increased CD3+ T-cells (P < .001), CD4+ helper T-cells (P < .001), γδ+ T-cells (P < .001), and FOXP3+ regulatory T-cells (P = .002). iSGS scar exhibited specific increases in CD90+ (P = .04) and SMA+ (P < .001) fibroblasts but decreased CD326+ (E-cadherin) epithelial cells (P = .01) relative to normal samples.

CONCLUSION

We present a comprehensive flow cytometry panel for iSGS. This flow panel may serve as a common platform among airway scientists to elucidate the cellular mechanisms underpinning iSGS and other upper airway pathologies. Scar iSGS samples demonstrate a distinct cellular profile relative to normal iSGS specimens, exhibiting increased fibroblast, endothelial, and inflammatory cell types but decreased epithelium.

From bench to bedside - is there a role of IL-17 drugs in rheumatoid arthritis?

INTRODUCTION

IL-17 has been described as a pro-inflammatory cytokine that is relevant in the seronegative spondylarthritides with IL-17 targeted therapies being licensed for their treatment.There is evidence to demonstrate that IL-17 is found in RA joints and contributes to the pro-inflammatory cascade. This results in synovial hyperplasia and osteoclastogenesis thus causing joint destruction and bony erosions.

AREAS COVERED

This review article summarizes trials that have studied the use of IL-17 targeted therapies in RA patients who have failed conventional synthetic disease-modifying therapy (C-DMARDS) and biologic DMARDS.

EXPERT OPINION

The trials that have studied IL-17 inhibitors in RA patients have only shown a modest improvement in disease activity. In several trials, the primary endpoint was not achieved whilst in others, when comparing with existing licensed biologics for RA, did not demonstrate any superiority.Tissue Necrosis Factor-alpha (TNF-α) likely plays more of a pivotal role in the pathogenesis of RA with IL-17 having a synergistic effect. Therefore, in our opinion, IL-17 inhibitors as an independent therapy for RA are less likely to provide a cost-effective benefit. There may be scope to potentially combine it with TNF-α-inhibitors (TNF-i), but this requires further research especially with the potential concerns related to increased immunosuppression.

C-reactive protein lowers the serum level of IL-17, but not TNF-α, and decreases the incidence of collagen-induced arthritis in mice

The biosynthesis of C-reactive protein (CRP) in the liver is increased in inflammatory diseases including rheumatoid arthritis. Previously published data suggest a protective function of CRP in arthritis; however, the mechanism of action of CRP remains undefined. The aim of this study was to evaluate the effects of human CRP on the development of collagen-induced arthritis (CIA) in mice which is an animal model of autoimmune inflammatory arthritis. Two CRP species were employed: wild-type CRP which binds to aggregated IgG at acidic pH and a CRP mutant which binds to aggregated IgG at physiological pH. Ten CRP injections were given on alternate days during the development of CIA. Both wild-type and mutant CRP reduced the incidence of CIA, that is, reduced the number of mice developing CIA; however, CRP did not affect the severity of the disease in arthritic mice. The serum levels of IL-17, IL-6, TNF-α, IL-10, IL-2 and IL-1β were measured: both wild-type and mutant CRP decreased the level of IL-17 and IL-6 but not of TNF-α, IL-10, IL-2 and IL-1β. These data suggest that CRP recognizes and binds to immune complexes, although it was not clear whether CRP functioned in its native pentameric or in its structurally altered pentameric form in the CIA model. Consequently, ligand-complexed CRP, through an as-yet undefined mechanism, directly or indirectly, inhibits the production of IL-17 and eventually protects against the initiation of the development of arthritis. The data also suggest that IL-17, not TNF-α, is critical for the development of autoimmune inflammatory arthritis.

Biomarker combination predicting imminent relapse after discontinuation of biological drugs in patients with rheumatoid arthritis in remission

OBJECTIVES

Compared to conventional disease-modifying antirheumatic drugs (DMARDs), biological DMARDs demonstrate superior efficacy but come with higher costs and increased infection risks. The ability to stop and resume biological DMARD treatment while maintaining remission would significantly alleviate these barriers and anxieties. The objective of this study was to identify biomarkers that can predict an imminent relapse, hopefully enabling the timely resumption of biological DMARDs before relapse occurs.

METHODS

Forty patients with rheumatoid arthritis who had been in remission for more than 12 months were included in the study. The patients discontinued their biological DMARD treatment and were monitored monthly for the next 24 months. Out of the 40 patients, 14 (35%) remained in remission at the end of the 24-month period, while 26 (65%) experienced relapses at different time points. Among the relapse cases, 13 patients experienced early relapse within 6 months, and another 13 patients had late relapse between 6 months and 24 months. Seventy-three cytokines in the sera collected longitudinally from the 13 patients with late relapse were measured by multiplex immunoassay. Using cytokines at two time points, immediately after withdrawal and just before relapse, volcano plot and area under the receiver operating characteristic curves (AUC) were drawn to select cytokines that distinguished imminent relapse. Univariate and multivariate logistic regression analyses were used for the imminent relapse prediction model.

RESULTS

IL-6, IL-29, MMP-3, and thymic stromal lymphopoietin (TSLP) were selected as potential biomarkers for imminent relapse prediction. All four cytokines were upregulated at imminent relapse time point. Univariate and multivariate logistic regression showed that a combination model with IL-6, MMP-3, and TSLP yielded an AUC of 0.828 as top predictors of imminent relapse.

CONCLUSIONS

This methodology allows for the prediction of imminent relapse while patients are in remission, potentially enabling the implementation of on- and off-treatments while maintaining remission. It also helps alleviate patient anxiety regarding the high cost and infection risks associated with biological DMARDs, which are the main obstacles to benefiting from their superb efficacy.

Single-cell RNA sequencing in juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is one of the most common chronic inflammatory rheumatic diseases in children, with onset before age 16 and lasting for more than 6 weeks. JIA is a highly heterogeneous condition with various consequences for health and quality of life. For some JIA patients, early detection and intervention remain challenging. As a result, further investigation of the complex and unknown mechanisms underlying JIA is required. Advances in technology now allow us to describe the biological heterogeneity and function of individual cell populations in JIA. Through this review, we hope to provide novel ideas and potential targets for the diagnosis and treatment of JIA by summarizing the current findings of single-cell RNA sequencing studies and understanding how the major cell subsets drive JIA pathogenesis.

Interleukin-17, C-reactive protein, Neutrophil-to-Lymphocyte ratio, Lymphocyte-to-Monocyte ratio, and lipid profiles in healthy menopausal women with or without hot flashes: A cross-sectional study

INTRODUCTION

The reciprocation between systemic inflammatory markers (SIMs), dyslipidemia, and hot flashes (HFs) can play a part in the pathogenesis of endothelial dysfunction through menopause. This study intended to determine the association between some SIMs, lipids, and HFs in healthy menopausal women.

MATERIALS AND METHODS

We designed a cross-sectional study in which 160 healthy menopausal women aged 40-60 were enrolled. Concerning their HFs status, they were stratified into two groups by consecutive sampling: without HFs (n = 40) and with HFs (n = 120). In addition to clinical variables and HFs experience, we measured the fasting serum levels of SIMs and lipid profiles (LPs), including Interleukin-17 (IL-17), high- sensitivity C-Reactive Protein (hs-CRP), Total Cholesterol (TC), Triglycerides (TG), Low-Density Lipoprotein Cholesterol (LDL-C), and High-Density Lipoprotein Cholesterol (HDL-C) in each group. Then, we calculated TC/HDL-C concerning the related variables and determined Neutrophil-to-Lymphocyte Ratio (NLR), and Lymphocyte-to-Monocyte Ratio (LMR), according to Complete Blood Count (CBC) quantitative parameters in each group. Furthermore, we used logistic regression analysis to assess the association between SIMs, LPs, and HFs.

SETTINGS

We performed this study in a governmental teaching hospital, Guilan/Rasht, Iran, from April to September 2021.

RESULTS

The two groups of menopausal women without and with HFs were not significantly different regarding the median of IL-17, hs-CRP, NLR, LMR, TG, HDL-C, and TC/HDL-C, and the mean of TC and LDL-C. Based on multiple logistic regression, TG levels appeared to be associated with the incidence of HFs (B = 0.004, P = 0.040, Odds Ratio:1.004, 95%CI:1.000-1.009). NLR seemed to have an increasing impact on the HFs severity, according to ordinal logistic regression (B = 0.779, P = 0.005, Odds Ratio = 2.180, 95%CI:1.270-3.744). Furthermore, hs-CRP negatively correlated with TG (r = -0.189, P = 0.039) and TC/HDL-C (r = -0.268, P = 0.003) in menopausal women with HFs.

CONCLUSION

This study indicated an association between SIMs, lipids, and HFs. These connections may suggest HFs as links between SIMs/LPs alterations and their outcomes.

The Fidelity of Rheumatoid Arthritis Multivariate Diagnostic Biomarkers Using Discriminant Analysis and Binary Logistic Regression

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease that causes multi-articular synovitis. The illness is characterized by worsening inflammatory synovitis, which causes joint swelling and pain. Synovitis erodes articular cartilage and marginal bone, resulting in joint deterioration. This bone injury is expected to be permanent. Cytokines play a prominent role in the etiology of RA and could be useful as early diagnostic biomarkers. This research was carried out at Riyadh's King Khalid University Hospital (KKUH). Patients were enrolled from the Rheumatology unit. Seventy-eight RA patients were recruited (67 (85.9%) females and 11 (14.1%) males). Patients were selected for participation by convenience sampling. Demographic data were collected, and disease activity measurements at 28 joints were recorded using the disease activity score (DAS-28). Age- and sex-matched controls from the general population were included in the study. A panel of 27 cytokines, chemokines, and growth factors was determined in patient and control sera. Binary logistic regression (BLR) and discriminant analysis (DA) were used to analyze the data. We show that multiple cytokine biomarker profiles successfully distinguished RA patients from healthy controls. IL-17, IL-4, and RANTES were among the most predictive variables and were the only biomarkers incorporated into both BLR and DA predictive models for pooled participants (men and women). In the women-only models, the significant cytokines incorporated in the model were IL-4, IL-17, MIP-1b, and RANTES for the BLR model and IL-4, IL-1Ra, GM-CSF, IL-17, and eotaxin for the DA model. The BLR and DA men-only models contained one cytokine each, eotaxin for BLR and platelet-derived growth factor-bb (PDGF-BB) for DA. We show that BLR has a higher fidelity in identifying RA patients than DA. We also found that the use of gender-specific models marginally improves detection fidelity, indicating a possible benefit in clinical diagnosis. More research is needed to determine whether this conclusion will hold true in various and larger patient populations.

New drug targets for the treatment of gout arthritis: what's new?

INTRODUCTION

Gout arthritis (GA) is an intermittent inflammatory disease affecting approximately 10% of the worldwide population. Symptomatic phases (acute flares) are timely spaced by asymptomatic periods. During an acute attack, redness, joint swelling, limited movement, and excruciating pain are common symptoms. However, the current available therapies are not fully effective in reducing symptoms and offer numerous side effects. Therefore, unveiling new drug targets and effector molecules are required in developing novel GA therapeutics.

AREAS COVERED

This review discusses the pathophysiological mechanisms of GA and explores potential pharmacological targets to ameliorate disease outcome. In addition, we listed promising pre-clinical studies demonstrating effector molecules with therapeutical potential. Among those, we emphasized the importance of natural products, including traditional Chinese medicine formulas and their multitarget mechanisms of action.

EXPERT OPINION

In our search, we observed that there is a massive gap between pre-clinical and clinical knowledge. Only a minority (4.4%) of clinical trials aimed to intervene by applying natural products or current hot targets described herein. In this sense, we envisage four possibilities for GA therapeutics, which include the repurposing of existing therapies, ALX/FPR2 agonism for improvement in disease outcome, the use of multitarget drugs (e.g. natural products), and targeting the neuroinflammatory component of GA.

The Airway Microbiome-IL-17 Axis: a Critical Regulator of Chronic Inflammatory Disease

The respiratory tract is home to a diverse microbial community whose influence on local and systemic immune responses is only beginning to be appreciated. Increasing reports have linked changes in this microbiome to a range of pulmonary and extrapulmonary disorders, including asthma, chronic obstructive pulmonary disease and rheumatoid arthritis. Central to many of these findings is the role of IL-17-type immunity as an important driver of inflammation. Despite the crucial role played by IL-17-mediated immune responses in protection against infection, overt Th17 cell responses have been implicated in the pathogenesis of several chronic inflammatory diseases. However, our knowledge of the influence of bacteria that commonly colonise the respiratory tract on IL-17-driven inflammatory responses remains sparse. In this article, we review the current knowledge on the role of specific members of the airway microbiota in the modulation of IL-17-type immunity and discuss how this line of research may support the testing of susceptible individuals and targeting of inflammation at its earliest stages in the hope of preventing the development of chronic disease.

Therapeutic potential of targeting IL-17 and its receptor signaling in neuroinflammation

T helper 17 cells are thought to significantly contribute to the neuroinflammation process during neurogenerative diseases via their signature cytokine, interleukin (IL)-17. Recently, an emerging key role of IL-17 and its receptors has been documented in inflammatory and autoimmune diseases. The clinical studies conducted on patients with neurodegenerative disease have also shown an increase in IL-17 levels in serum as well as cerebrospinal fluid samples. Therapeutic targeting of either IL-17 receptors or direct IL-17 neutralizing antibodies has shown a promising preclinical and clinical proof of concept for treating chronic autoimmune neurodegenerative diseases such as multiple sclerosis. Thus, IL-17 and its receptors have a central role in regulation of neuroinflammation and can be considered as one of the major therapeutic targets in chronic neuroinflammatory diseases.

Echinocystic Acid Ameliorates Arthritis in SKG Mice by Suppressing Th17 Cell Differentiation and Human Rheumatoid Arthritis Fibroblast-Like Synoviocytes Inflammation

Echinocystic acid (EA), a pentacyclic triterpene, exhibits anti-inflammatory, antioxidant, and analgesic activities to counteract pathological effects in various diseases. Here, we aimed to determine the immunomodulatory effect of EA on zymosan-induced arthritis in SKG mice and how it would influence Th17 differentiation and human rheumatoid arthritis fibroblast-like synoviocytes inflammation. Our results showed that EA (10 and 25 mg/kg) attenuated arthritis symptoms, including high arthritis scores, infiltrating inflammatory cells, synovial hyperplasia, bone erosion, and the high levels of proinflammatory cytokines, such as TNF-α, interleukin (IL)-6, and IL-1β in paw tissues, and reduced the number of splenic Th17 cells. Mechanistically, we found that in vitro treatment of EA inhibited both IL-6- and transforming growth factor-β (TGF-β)-induced Th17 cell differentiation by suppressing the phosphorylation of signal transducers and transcriptional activators, especially STAT3. In line with the in vivo result, EA significantly reduced the protein and mRNA expression of IL-6 and IL-1β in human RA-FLA cells, MH7A cells. Furthermore, the production of both cytokines was confirmed with the downregulation of mitogen-activated protein kinases (MAPK) and nuclear factor-κB (NF-κB) signaling pathways under the stimulation of TNF-α. In conclusion, these findings revealed that EA was capable of amelioration of arthritic disorders in SKG mice through inhibiting Th17 cell differentiation and synovial fibroblast inflammation, supporting that EA is a promising therapeutic candidate for treating RA patients.

Semaphorin 4D induces articular cartilage destruction and inflammation in joints by transcriptionally reprogramming chondrocytes

Proinflammatory cytokines play critical roles in the pathogenesis of joint diseases. Using a mass spectrometry-based cloning approach, we identified Semaphorin 4D (Sema4D) as an inflammatory cytokine that directly promoted cartilage destruction. Sema4d-deficient mice showed less cartilage destruction than wild-type mice in a model of rheumatoid arthritis. Sema4D induced a proinflammatory response in mouse articular chondrocytes characterized by the induction of proteolytic enzymes that degrade cartilage, such as matrix metalloproteinases (MMPs) and aggrecanases. The activation of Mmp13 and Mmp3 expression in articular chondrocytes by Sema4D did not depend on RhoA, a GTPase that mediates Sema4D-induced cytoskeletal rearrangements. Instead, it required NF-κB signaling and Ras-MEK-Erk1/2 signaling downstream of the receptors Plexin-B2 and c-Met and depended on the transcription factors IκBζ and C/EBPδ. Genetic and pharmacological blockade of these Sema4D signaling pathways inhibited MMP induction in chondrocytes and cartilage destruction in femoral head organ culture. Our results reveal a mechanism by which Sema4D signaling promotes cartilage destruction.

Antibacterial and Anti-Inflammatory Potential of Chinese Medicinal Herbs: Lonicerae flos, Lonicerae japonicae flos, Scutellaria baicalensis Georgi, and Forsythia suspensa

Chinese herbal medicine (CHM) represents a potent, safe, and efficacious reservoir of treatment options against an array of microbial infections and inflammatory diseases. It has a long history of positive clinical outcomes with minimal or no side effects while enhancing and bolstering the host's protection against infections. With its unique ability to prevent, treat, and manage a wide range of diseased conditions, CHM has been successfully practiced in China for thousands of years. In the modern medical era, where harsh therapeutic drugs and antimicrobial resistance (AMR) present a significant challenge, CHM warrants further exploration. The present review highlights and focuses on 4 major CHM-based herbs, that is, ( Lonicerae flos [ LF] , Lonicerae japonicae flos [ LJF] , Scutellaria baicalensis Georgi [ SBG] , and Forsythia suspensa [ FS]) in terms of their antibacterial and anti-inflammatory efficacies. A detailed literature survey was done by the team using a systematic electronic search from PubMed, Science Direct, Google Scholar, Research Gate, books, etc. This was followed by data collecting, pertinent data extraction, in-depth analysis, and composing the final review. Each herb has been discussed in detail describing its mechanism adopted and the bioactive components involved in alleviating bacterial infections and inflammatory damage. Further, proof of efficacy by detailing the major past studies and major findings has been discussed for each of the 4 herbs. This review will give the scientific community the opportunity to update their knowledge on the subject, which is crucial for heralding the process of bringing CHM-based medicines closer to clinical development given the area of alternative medicine's rapid advancements.

Not all T cell epitopes are equally desired: a review of in silico tools for the prediction of cytokine-inducing potential of T-cell epitopes

Assessment of protective or harmful T cell response induced by any antigenic epitope is important in designing any immunotherapeutic molecule. The understanding of cytokine induction potential also helps us to monitor antigen-specific cellular immune responses and rational vaccine design. The classical immunoinformatics tools served well for prediction of B cell and T cell epitopes. However, in the last decade, the prediction algorithms for T cell epitope inducing specific cytokines have also been developed and appreciated in the scientific community. This review summarizes the current status of such tools, their applications, background algorithms, their use in experimental setup and functionalities available in the tools/web servers.

Toxoplasmosis Frequency Rate in Rheumatoid Arthritis Patients in Northeastern Iran

BACKGROUND

Toxoplasmosis is a zoonotic disease caused by the parasite Toxo-plasma gondii, a cosmopolitan intracellular parasite. It can be a risk factor for auto-immune diseases, including rheumatoid arthritis (RA). This study was designed to investigate the possible association between serological history of T. gondii infection and defined clinical manifestation of RA in Northeast of Iran.

METHODS

Overall, serum samples were collected from 50 RA patients and 40 healthy controls, from Qaem Hospital in Mashhad City, northeastern Iran in 2018. Seroprevalence of T. gondii infection was determined by ELISA.

RESULTS

The prevalence of anti -T. gondii IgG in RA patients 48% (24.50) was significantly higher than the control group 10% (4.40) (P <0.001). Erythrocyte sedimentation rate (ESR), anti-cyclic citrullinated peptide (anti-CCP) and (rheumatoid factor) RF levels between the RA and control groups (P <0.01). Control group were matched with patients for age, gender and living area.

CONCLUSION

Given that a high correlation has been demonstrated between positivity rate of anti-T. gondii IgG and RA in Northeastern Iran, further studies will be necessary to clarify the pathogenesis of T. gondii among these patients.

Radiation Exposure Perturbs IL-17RA-Mediated Immunity Leading to Changes in Neutrophil Responses That Increase Susceptibility to Oropharyngeal Candidiasis

Fungal infections caused by Candida albicans are a serious problem for immunocompromised individuals, including those undergoing radiotherapy for head and neck cancers. Targeted irradiation causes inflammatory dysregulation and damage to the oral mucosa that can be exacerbated by candidiasis. Post-irradiation the cytokine interleukin-17 (IL-17) protects the oral mucosae by promoting oral epithelial regeneration and balancing the oral immune cell populations, which leads to the eventual healing of the tissue. IL-17 signaling is also critical for the antifungal response during oropharyngeal candidiasis (OPC). Yet, the benefit of IL-17 during other forms of candidiasis, such as vulvovaginal candidiasis, is not straightforward. Therefore, it was important to determine the role of IL-17 during OPC associated with radiation-induced inflammatory damage. To answer this question, we exposed Il17ra^−/− and wild-type mice to head-neck irradiation (HNI) and OPC to determine if the IL-17 signaling pathway was still protective against C. albicans. HNI increased susceptibility to OPC, and in Il17ra^−/− mice, the mucosal damage and fungal burden were elevated compared to control mice. Intriguingly, neutrophil influx was increased in Il17ra^−/− mice, yet these cells had reduced capacity to phagocytose C. albicans and failed to clear OPC compared to immunocompetent mice. These findings suggest that radiotherapy not only causes physical damage to the oral cavity but also skews immune mediators, leading to increased susceptibility to oropharyngeal candidiasis.

Prophylactic or therapeutic administration of Holarrhena floribunda hydro ethanol extract suppresses complete Freund's adjuvant-induced arthritis in Sprague-Dawley rats

BACKGROUND

A hydro ethanol extract of the stem bark of Holarrhena floribunda (HFE) has been shown to be effective in the management of acute inflammation. This study was to evaluate usefulness of the extract for the management of chronic inflammation in a murine model.

METHODS

Arthritis was induced in Sprague-Dawley rats using Complete Freund's Adjuvant. Anti-arthritic effect of the extract was evaluated in prophylactic and therapeutic treatment models at doses of 50, 200 and 500 mg/kg. Parameters assessed included oedema, serology of inflammatory response, bone tissue histology and haematology. Data were analysed by ANOVA and Tukey's multiple comparisons post hoc test.

RESULTS

HFE at 50-500 mg/kg dose-dependently [P ≥ 0.0354 (prophylactic) and P ≥ 0.0001 (therapeutic) inhibited swelling of the injected paw upon prophylactic [≤ 81.26% (P < 0.0001) or therapeutic [≤ 67.92% (P < 0.01) administration - and prevented spread of arthritis to the contralateral paw. The inflammation alleviation activity was further demonstrated by decrease in arthritis score, radiologic score and erythrocyte sedimentation rate. HFE at all doses significantly reduced serum interleukin (IL)-1α (P < 0.0197), and 500 mg/kg HFE reduced IL-6 (P = 0.0032). In contrast, serum concentrations of IL-10, protein kinase A and cyclic adenosine monophosphate were enhanced (P ≤ 0.0436). HFE consistently showed better prophylactic than therapeutic activity.

CONCLUSION

HFE strongly suppressed Complete Freund's Adjuvant-induced arthritis and modulated regulators of inflammation, including IL-1α, - 6 and - 10. Taken together, the data suggest that HFE has potential for use as an agent for modulation of the inflammatory response.

Alteration of Gut Microbiome and Correlated Amino Acid Metabolism Contribute to Hyperuricemia and Th17-Driven Inflammation in Uox-KO Mice

Although gut dysbiosis had been demonstrated to be an important factor affecting hyperuricemia (HUA) and gout, little is known for its potential mechanistic connections. In this study, Uox-KO mice model that with spontaneously developed pronounced HUA and urate nephropathy was used to explore the pathophysiologic mechanism of microbiota alterations in HUA and gout with integrated multi-omics analysis. 16S rRNA gene sequencing was performed to characterize the characteristic bacteria, and untargeted LC/MS analysis was applied to reveal the featured metabolites. Our results showed there was a significant shift in gut microbiota composition and function in Uox-KO mice compared to WT mice and apparent metabolomics differences between the two groups. Among them, amino acids metabolism appears to play a critical role. Correlation analysis further revealed that the characteristic metabolites were strongly influenced by the discrepant bacterial genera. Furthermore, impairment of intestinal integrity and profound alterations in the profile of solute carrier family resulted in dysregulation of amino acids transportation, which subsequently impacted serum uric acid level and CD4⁺ Th17 driven inflammation. Together, these data indicate that gut dysbiosis promotes purine metabolism disorder and inflammation in Uox-KO mice. Remodeling the gut microbiota is a promising strategy to combat HUA and gout.

Propionibacterium freudenreichii Inhibits RANKL-Induced Osteoclast Differentiation and Ameliorates Rheumatoid Arthritis in Collagen-Induced Arthritis Mice

Osteoclast differentiation is crucial for bone absorption, and osteoclasts are involved in bone destruction in rheumatoid arthritis (RA). Dairy Propionibacterium freudenreichii is used as a cheese starter and possesses prebiotic and postbiotic properties. It is known to stimulate the growth of bifidobacteria and produces valuable metabolites, such as vitamin B12 and propionic acid. However, limited information is available on the beneficial effects of P. freudenreichii on human disease. Herein, we aimed to investigate the inhibitory effect of P. freudenreichii MJ2 (MJ2) isolated from raw milk on osteoclast differentiation and evaluate the improvement in RA. The murine macrophage cell line, RAW 264.7, and a collagen-induced arthritis (CIA) mouse model were used to perform in vitro and in vivo studies, respectively. Heat-killed P. freudenreichii MJ2 (hkMJ2)-treated cells significantly inhibited RANKL-induced osteoclast differentiation and TRAP activity. HkMJ2-treated cells exhibited significantly decreased expression of genes and proteins related to RANKL-induced osteoclast differentiation. MJ2 administration decreased the arthritic score in the CIA mouse model. Live and dead MJ2 inhibited bone loss and afforded protection against bone erosion and joint damage in CIA mice. MJ2 decreased the levels of collagen-specific antibodies and inflammatory cytokines and the expression of osteoclast differentiation-related genes and proteins in CIA mice. Interestingly, live and dead MJ2 showed similar RA improvement effects in CIA mice. In conclusion, P. freudenreichii MJ2 inhibited osteoclast differentiation by inhibiting the NF-κB signaling pathway and ameliorated CIA.

Iguratimod reduces panel reactive antibody in high mismatched renal transplant recipients: One single-center experience

OBJECTIVE

To evaluate the clinical efficacy and safety of iguratimod (IGU) for reducing panel reactive antibody (PRA) in high-mismatched renal transplant recipients.

METHODS

Eligible recipients positive for PRAs who received or did not receive IGU treatment were enrolled. We retrospectively reviewed, collected, and analyzed statistically the clinical data of the recipients.

RESULTS

A total of 80 recipients were included for further analysis. After IGU was administered for nine months, no significant difference was found in the change rates of donor specific antibodies between two groups. Meanwhile, the reduction in the PRAs in the IGU group was greater than that in the non-IGU group in anti-human leukocyte antigen (HLA) class I and class II, anti-HLA class I, anti-HLA class II, anti-HLA A, and anti-HLA DR antibodies. However, no differences were found in the anti-HLA B, anti-HLA Cw, anti-HLA DP, and anti-HLA DQ antibodies between the two groups. No serious adverse events were reported, and the incidence of adverse events was comparable between the two groups.

CONCLUSION

PRA levels in high-mismatched renal transplant recipients were significantly reduced after the administration of IGU. The high safety of IGU was also determined. This article is protected by copyright. All rights reserved.

Twist1 Influences the Expression of Leading Members of the IL-17 Signaling Pathway in HER2-Positive Breast Cancer Cells

Breast cancer (BC) is a heterogeneous disease composed of multiple subtypes with different molecular characteristics and clinical outcomes. The metastatic process in BC depends on the transcription factors (TFs) related to epithelial-mesenchymal transition (EMT), including the master regulator Twist1. However, its role beyond EMT in BC subtypes remains unclear. Our study aimed to investigate the role of Twist1, beyond EMT, in the molecular subtypes of BC. In patients, we observed the overexpression of TWIST1 in the HER2+ group. The silencing of TWIST1 in HER2+ BC cells resulted in the upregulation of 138 genes and the downregulation of 174 genes compared to control cells in a microarray assay. In silico analysis revealed correlations between Twist1 and important biological processes such as the Th17-mediated immune response, suggesting that Twist1 could be relevant for IL-17 signaling in HER2+ BC. IL-17 signaling was then examined, and it was shown that TWIST1 knockdown caused the downregulation of leading members of IL-17 signaling pathway. Taken together, our findings suggest that Twist1 plays a role on IL-17 signaling in HER2+ BC.

Gender-Related Differences in BMP Expression and Adult Hippocampal Neurogenesis within Joint-Hippocampal Axis in a Rat Model of Rheumatoid Arthritis

BMPs regulate synovial quiescence and adult neurogenesis in the hippocampus in non-stress conditions. However, changes in BMP expression that are induced by inflammation during rheumatoid arthritis (RA) have not yet been reported. Here, we show that signalling with synovial BMPs (BMP-4 and -7) mediates the effect of systemic inflammation on adult neurogenesis in the hippocampus during pristane-induced arthritis (PIA) in Dark Agouti (DA) rats, an animal model of RA. Moreover, we show gender differences in BMP expressions and their antagonists (Noggin and Gremlin) during PIA and their correlations with the clinical course and IL-17A and TNF-α levels in serum. Our results indicate gender differences in the clinical course, where male rats showed earlier onset and earlier recovery but a worse clinical course in the first two phases of the disease (onset and peak), which correlates with the initial increase of serum IL-17A level. The clinical course of the female rats worsened in remission. Their prolonged symptoms could be a reflection of an increased TNF-α level in serum during remission. Synovial inflammation was greater in females in PIA-remission with greater synovial BMP and antagonist expressions. More significant correlations between serum cytokines (IL-17A and TNF-α), and synovial BMPs and their antagonists were found in females than in males. On the other hand, males showed an increase in hippocampal BMP-4 expression during the acute phase, but both genders showed a decrease in antagonist expressions during PIA in general. Both genders showed a decrease in the number of Ki-67⁺ and SOX-2⁺ and DCX⁺ cells and in the ratio of DCX⁺ to Ki67⁺ cells in the dentate gyrus during PIA. However, in PIA remission, females showed a faster increase in the number of Ki67⁺, SOX-2⁺, and DCX⁺ cells and a faster increase in the DCX/Ki67 ratio than males. Both genders showed an increase of hippocampal BMP-7 expression during remission, although males constantly showed greater BMP-7 expression at all time points. Our data show that gender differences exist in the BMP expressions in the periphery-hippocampus axis and in the IL-17A and TNF-α levels in serum, which could imply differences in the mechanisms for the onset and progression of the disease, the clinical course severity, and adult neurogenesis with subsequent neurological complications between genders.

IL-36 in chronic inflammation and fibrosis - bridging the gap?

IL-36 is a member of the IL-1 superfamily and consists of three agonists and one receptor antagonist (IL-36Ra). The three endogenous agonists, IL-36α, -β, and -γ, act primarily as proinflammatory cytokines, and their signaling through the IL-36 receptor (IL-36R) promotes immune cell infiltration and secretion of inflammatory and chemotactic molecules. However, IL-36 signaling also fosters secretion of profibrotic soluble mediators, suggesting a role in fibrotic disorders. IL-36 isoforms and IL-36 have been implicated in inflammatory diseases including psoriasis, arthritis, inflammatory bowel diseases, and allergic rhinitis. Moreover, IL-36 has been connected to fibrotic disorders affecting the kidney, lung, and intestines. This review summarizes the expression, cellular source, and function of IL-36 in inflammation and fibrosis in various organs, and proposes that IL-36 modulation may prove valuable in preventing or treating inflammatory and fibrotic diseases and may reveal a mechanistic link between inflammation and fibrosis.

A myostatin-CCL20-CCR6 axis regulates Th17 cell recruitment to inflamed joints in experimental arthritis

The interactions of fibroblast-like synoviocyte (FLS)-derived pro-inflammatory cytokines/chemokines and immune cells support the recruitment and activation of inflammatory cells in RA. Here, we show for the first time that the classical myokine myostatin (GDF-8) is involved in the recruitment of Th17 cells to inflammatory sites thereby regulating joint inflammation in a mouse model of TNFalpha-mediated chronic arthritis. Mechanistically, myostatin-deficiency leads to decreased levels of the chemokine CCL20 which is associated with less infiltration of Th17 cells into the inflamed joints. In vitro, myostatin alone or in combination with IL-17A enhances the secretion of CCL20 by FLS whereas myostatin-deficiency reduces CCL20 secretion, associated with an altered transmigration of Th17 cells. Thus, the communication between activated FLS and Th17 cells through myostatin and IL-17A may likely contribute to a vicious cycle of inflammation, accounting for the persistence of joint inflammation in chronic arthritis. Blockade of the CCL20–CCR6 axis by inhibition of myostatin may, therefore, be a promising treatment option for chronic inflammatory diseases such as arthritis.

Association of interleukin-17A rs2275913 polymorphism with rheumatoid arthritis susceptibility in Sudanese population

Objectives:

Rheumatoid arthritis is a chronic inflammatory autoimmune disease. This study aimed to determine the association of interleukin-17A-197G/A polymorphism with rheumatoid arthritis in Sudanese patients.

Methods:

A case–control study was conducted between March and December 2018. Clinical and demographic data of the study participants were collected and analyzed. Polymerase chain reaction restriction fragment length polymorphism molecular technique was done to investigate interleukin-17A-197G/A polymorphisms. All statistical tests were considered statistically significant when p < 0.05.

Results:

The study population included 266 participants aged between 1 and 85 years, with an average of 40 years, classified into 85 (31.2%) cases (mean age 48.5 ± 11.3 years), and 181 (68.8%) controls (mean age 35.3 ± 15.9 years). The interleukin-17A homozygote AA genotype was more frequent among the control group compared to the case group; 95 (52.5%) and 7 (8.2%), respectively. The homozygote GG and the heterozygote AG genotypes were proportionally not different among the cases and control groups; 13 (54.2%) and 11 (45.8%), and 65 (46.4%) and 75 (53.6%), respectively. According to the distribution of interleukin-17A genotypes, a statistically significant difference was observed among cases with the interleukin-17A AA and AG genotypes, p values 0.001 and 0.004, respectively. For the association interleukin-17A genotypes and family history a negatively significant association was reported (95% confidence interval, –0.219, p value = 0.001). There was also a negatively significant association of interleukin-17A genotypes and anti-cyclic citrullinated peptide (95% confidence interval, −0.141, p value = 0.002).

Conclusion:

This study is the first study in Sudan established the association between interleukin-17A-197G/A (rs2275913) polymorphisms and susceptibly to rheumatoid arthritis. These findings appeal for further research in Sudan to investigate the exact role of IL-17A in immunopathology and disease severity among Sudanese rheumatoid arthritis

The Therapeutic Landscape of Rheumatoid Arthritis: Current State and Future Directions

Rheumatoid arthritis (RA) is a debilitating autoimmune disease with grave physical, emotional and socioeconomic consequences. Despite advances in targeted biologic and pharmacologic interventions that have recently come to market, many patients with RA continue to have inadequate response to therapies, or intolerable side effects, with resultant progression of their disease. In this review, we detail multiple biomolecular pathways involved in RA disease pathogenesis to elucidate and highlight pathways that have been therapeutic targets in managing this systemic autoimmune disease. Here we present an up-to-date accounting of both emerging and approved pharmacological treatments for RA, detailing their discovery, mechanisms of action, efficacy, and limitations. Finally, we turn to the emerging fields of bioengineering and cell therapy to illuminate possible future targeted therapeutic options that combine material and biological sciences for localized therapeutic action with the potential to greatly reduce side effects seen in systemically applied treatment modalities.

Biomarker Approach Towards Rheumatoid Arthritis Treatment

Rheumatoid arthritis is an auto-immune disorder, recognized by cartilage as well as bone destruction, which causes irreversible joint deformities, which further results in functional limitations in the patient. Genes like HLA-DRB1 and PTPN22 are likely implicated in the genetic predisposition of rheumatoid arthritis pathology. The first and foremost clinical manifestation in a person with rheumatoid arthritis is joint destruction followed by cartilage and bone destruction caused by cell-cell interactions. The cell-cell interactions are thought to be initialized through the contact of antigen-presenting cells (APC) with CD4+ cells, leading to the progression of the disease. APC includes a complex of class ІІ major histocompatibility complex molecules along with peptide antigens and binds to the receptors present on the surface of T-cells. Further, the activation of macrophages is followed by the release of various pro-inflammatory cytokines such as IL-1 and TNF-α, which lead to the secretion of enzymes that degrade proteoglycan and collagen, which in turn, increase tissue degradation. Biomarkers like IL-6, IL-12, IL-8 and IL-18, 14-3-3η, RANKL, IFN-γ, IFN-β and TGF-β have been designated as key biomarkers in disease development and progression. The study of these biomarkers is very important as they act as a molecular indicator of pathological processes that aggravate the disease.

Effect of Epstein-Barr Virus DNA on the Incidence and Severity of Arthritis in a Rheumatoid Arthritis Mouse Model

Objective

We recently demonstrated that EBV DNA is correlated with proinflammatory responses in mice and in rheumatoid arthritis (RA) patients; hence, we utilized an RA mouse model to examine whether EBV DNA enhances the risk and severity of arthritis and to assess its immunomodulatory effects.

Methods

C57BL/6J mice were treated with collagen (arthritis-inducing agent), EBV DNA 6 days before collagen, EBV DNA 15 days after collagen, Staphylococcus epidermidis DNA 6 days before collagen, EBV DNA alone, or water. Mice were then monitored for clinical signs and affected joints/footpads were histologically analysed. The relative concentration of IgG anti- chicken collagen antibodies and serum cytokine levels of IL-17A and IFNϒ were determined by ELISA. The number of cells co-expressing IL-17A and IFNϒ in joint histological sections was determined by immunofluorescence.

Results

The incidence of arthritis was significantly higher in mice that received EBV DNA prior to collagen compared to mice that only received collagen. Similarly, increased clinical scores, histological scores and paw thicknesses with a decreased gripping strength were observed in groups treated with EBV DNA and collagen. The relative concentration of IgG anti-chicken collagen antibodies was significantly increased in the group that received EBV DNA 6 days prior to collagen in comparison to the collagen receiving group. On the other hand, the highest number of cells co-expressing IFNϒ and IL-17A was observed in joints from mice that received both collagen and EBV DNA.

Conclusion

EBV DNA increases the incidence and severity of arthritis in a RA mouse model. Targeting mediators triggered by viral DNA may hence be a potential therapeutic avenue.

Impact of Three Different Serum Sources on Functional Properties of Equine Mesenchymal Stromal Cells

Culture and expansion of equine mesenchymal stromal cells (MSCs) are routinely performed using fetal bovine serum (FBS) as a source of growth factors, nutrients, and extracellular matrix proteins. However, the desire to minimize introduction of xenogeneic bovine proteins or pathogens and to standardize cellular products intended for clinical application has driven evaluation of alternatives to FBS. Replacement of FBS in culture for several days before administration has been proposed to reduce antigenicity and potentially prolong survival after injection. However, the functional consequences of MSC culture in different serum types have not been fully evaluated. The objective of this study was to compare the immunomodulatory and antibacterial properties of MSCs cultured in three serum sources: FBS or autologous or allogeneic equine serum. We hypothesized that continuous culture in FBS would generate MSCs with improved functionality compared to equine serum and that there would not be important differences between MSCs cultured in autologous vs. allogeneic equine serum. To address these questions, MSCs from three healthy donor horses were expanded in medium with FBS and then switched to culture in FBS or autologous or allogeneic equine serum for 72 h. The impact of this 72-h culture period in different sera on cell viability, cell doubling time, cell morphology, bactericidal capability, chondrogenic differentiation, and production of cytokines and antimicrobial peptides was assessed. Altering serum source did not affect cell viability or morphology. However, cells cultured in FBS had shorter cell doubling times and secreted more interleukin 4 (IL-4), IL-5, IL-17, RANTES, granulocyte–macrophage colony-stimulating factor, fibroblast growth factor 2, eotaxin, and antimicrobial peptide cathelicidin/LL-37 than cells cultured in either source of equine serum. Cells cultured in FBS also exhibited greater spontaneous bactericidal activity. Notably, significant differences in any of these parameters were not observed when autologous vs. allogeneic equine serum was used for cell culture. Chondrogenic differentiation was not different between different serum sources. These results indicate that MSC culture in FBS will generate more functional cells based on a number of parameters and that the theoretical risks of FBS use in MSC culture should be weighed against the loss of MSC function likely to be incurred from culture in equine serum.

Tibetan medicine Ershiwuwei Lvxue Pill attenuates collagen-induced arthritis via inhibition of JAK2/STAT3 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ershiwuwei Lvxue Pill (ELP, མགྲིན་མཚལ་ཉེར་ལྔ།), a traditional Tibetan medicine preparation, has been used hundreds of years for the clinical treatment of rheumatoid arthritis (RA) in the highland region of Tibet, China. However, the underlying mechanism of its therapeutic effect remains unclear.

AIM OF THE STUDY

The present study aimed to investigate the potential pharmacological mechanisms of anti-arthritic effect of ELP.

MATERIALS AND METHODS

The main chemical constituents of ELP were analyzed by ultra-performance liquid chromatography quadrupole-time-flight mass spectrometry (UPLC-Q-TOF-MS). Forty-eight male Wistar rats (220 ± 20 g) were randomly divided into six groups: normal group, collagen-induced arthritis (CIA) group, methotrexate group (1.05 mg/kg), ELP groups (115, 230 and 460 mg/kg). CIA rat models were assigned to evaluate the anti-RA activity of ELP by determining the paws swelling, arthritis score, organ coefficients of spleen and thymus, and histopathological analysis of knee joints of synovial tissues. The levels of TNF-α, IL-10, IL-6 and IL-17 in serum were measured by ELISA. In addition, mRNA and protein expression levels associated with JAK2/STAT3 signaling pathway in synovial tissues of CIA rats were detected by qRT-PCR, immunohistochemistry and Western blot analyses.

RESULTS

Fourteen main chemical constituents of ELP were quantitatively determined by UPLC-Q-TOF-MS analysis. Treatment with ELP reduced the paw swelling, arthritis score and organ coefficients of spleen and thymus. Histopathological examination revealed the protective effects of ELP on CIA rats with knee joint injury. The levels of serum pro-inflammatory cytokines (TNF-α, IL-6 and IL-17) were markedly reduced while the anti-inflammatory cytokine IL-10 was significantly increased with the treatment of ELP. Further investigations showed ELP down-regulated the mRNA and protein expression levels of Bcl-2, whereas up-regulated Bax, SOCS1 and SOCS3. Meanwhile, the ratios of p-JAK2/JAK2 and p-STAT3/STAT3 proteins from synovial tissues were dramatically decreased with the treatment of ELP, whereas no changes of the mRNA and protein expression levels of JAK2 and STAT3 were observed.

CONCLUSION

These results indicated that ELP reduced the severity of arthritis and joint swelling, suggesting an antirheumatic effect on CIA rats. The possible mechanism is related to inhibiting inflammatory response and inducing apoptosis in synovial tissues by regulating JAK2/STAT3 signaling pathway. However, further in vivo and in vitro investigations are still needed to clarify the underlying mechanism of ELP in treating RA.

Chemokine Receptor 5 Antagonism Causes Reduction in Joint Inflammation in a Collagen-Induced Arthritis Mouse Model

Rheumatoid arthritis (RA) is a chronic inflammatory disease mainly affecting the synovial joints. A highly potent antagonist of C-C chemokine receptor 5 (CCR5), maraviroc (MVC), plays an essential role in treating several infectious diseases but has not yet been evaluated for its potential effects on RA development. This study focused on evaluating the therapeutic potential of MVC on collagen-induced arthritis (CIA) in DBA/1J mice. Following CIA induction, animals were treated intraperitoneally with MVC (50 mg/kg) daily from day 21 until day 35 and evaluated for clinical score and histopathological changes in arthritic inflammation. We further investigated the effect of MVC on Th9 (IL-9, IRF-4, and GATA3) and Th17 (IL-21R, IL-17A, and RORγT) cells, TNF-α, and RANTES in CD8+ T cells in the spleen using flow cytometry. We also assessed the effect of MVC on mRNA and protein levels of IL-9, IL-17A, RORγT, and GATA3 in knee tissues using RT-PCR and western blot analysis. MVC treatment in CIA mice attenuated the clinical and histological severity of inflammatory arthritis, and it substantially decreased IL-9, IRF4, IL-21R, IL-17A, RORγT, TNF-α, and RANTES production but increased GATA3 production in CD8+ T cells. We further observed that MVC treatment decreased IL-9, IL-17A, and RORγt mRNA and protein levels and increased those of GATA3. This study elucidates the capacity of MVC to ameliorate the clinical and histological signs of CIA by reducing pro-inflammatory responses, suggesting that MVC may have novel therapeutic uses in the treatment of RA.

Shared recognition of citrullinated tenascin-C peptides by T and B cells in rheumatoid arthritis

Tenascin-C (TNC), an extracellular matrix protein that has proinflammatory properties, is a recently described antibody target in rheumatoid arthritis (RA). In this study, we utilized a systematic discovery process and identified 5 potentially novel citrullinated TNC (cit-TNC) T cell epitopes. CD4⁺ T cells specific for these epitopes were elevated in the peripheral blood of subjects with RA and showed signs of activation. Cit-TNC–specific T cells were also present among synovial fluid T cells and secreted IFN-γ. Two of these cit-TNC T cell epitopes were also recognized by antibodies within the serum and synovial fluid of individuals with RA. Detectable serum levels of cit-TNC–reactive antibodies were prevalent among subjects with RA and positively associated with cyclic citrullinated peptide (CCP) reactivity and the HLA shared epitope. Furthermore, cit-TNC–reactive antibodies were correlated with rheumatoid factor and elevated in subjects with a history of smoking. This work confirms cit-TNC as an autoantigen that is targeted by autoreactive CD4⁺ T cells and autoantibodies in patients with RA. Furthermore, our findings raise the possibility that coinciding epitopes recognized by both CD4⁺ T cells and B cells have the potential to amplify autoimmunity and promote the development and progression of RA.

Interleukin- 17agene Polymorphism, Serum Level and Its Tissue Expression in Iraqi Patients Gastric Lesions

BACKGROUND

T-helper 17 plays a novel role in inflammation in gastritis by producing IL-17A, IL-17A gene polymorphisms that might be responsible for disease susceptibility and development of different gastric lesions.

OBJECTIVE

The aims of study was to determine the association of IL-17A (G197A) genotype and allele frequency with disease phenotype and risk with different gastric lesions.

METHODS

Case controlled study involved 30 gastroduodenal ulcer, 30 chronic gastritis and 30 subjects as a control group with negative endoscopic findings. After genomic DNA extraction, IL-17A (G197A)ARMS-PCR genotyping were done for all cases. Serum IL-17A was measured using ELISA method and tissue expression was visualized using immunohistochemistry staining method.

RESULTS

The results showed that allele A was significantly frequent in gastroduodenal ulcer more than that in healthy control odd ratio= 4 (1.42-10.46), and none significantly with chronic gastritis p=0.071. Serum IL-17A was significantly higher in gastroduodenal ulcer (116.45±48.09 pg/ml), chronic gastritis (78.02±30.17pg/ml) and healthy control 19.36±9.28 pg/ml).However, the serum IL-17A level is not related to the allele pattern of each group. The tissue expression was expressed as dense granular cytoplasmic and membranous of inflammatory cells. Interestingly, the percentage of IL-17A protein expression was significantly higher in gastroduodenal ulcer (38.2±16.55%), chronic gastritis (30.89±14.02%) and normal mucosa (2.8±3.02%). Furthermore, patients with strong intensity of IL-17A stained mucosa were frequently carrier for mutant allele (68%).

CONCLUSION

IL-17A might predispose for aggressive inflammation of advanced lesions in stomach like ulcer.

Understanding Refractory Rheumatoid Arthritis: Implications for a Therapeutic Approach

Refractory rheumatoid arthritis (RA) has emerged as an area of unmet need in a landscape of generally well-controlled disease. Whilst most patients are adequately treated on methotrexate and other first-line disease-modifying anti-rheumatic drugs (DMARDs), a proportion requires biologic (b) and targeted synthetic (ts) DMARDs, with a further subsection failing multiple agents. Recent observational studies have adopted working definitions of refractory RA based on number of failed DMARDs, with prevalence estimates of 6-21% depending on threshold and study population. Risk factors include treatment delay, baseline disease activity and function, female gender, smoking, obesity and lower socioeconomic status. Practical and conceptual challenges in defining refractory RA arise from limitations of disease activity scores used to assess response, with attendant misclassification risk of co-existent non-inflammatory pathology, and failure to capture additional outcomes, such as fatigue, that have variable treatment response. Time is an important factor in defining refractory disease; registry studies show that growing treatment options have resulted in rapid b/tsDMARD cycling and earlier refractory status, and refractory RA is itself a dynamic concept, evolving with each new therapeutic class. Whilst the biology underpinning refractory RA remains largely unknown, a general overview of biomarker studies and clinical trials old and new offers insights into prediction of response and treatment failure. Whilst the future holds promise, current data are insufficient to personalise or meaningfully sequence b/tsDMARDs. Therefore, avoidance of a refractory course is best achieved by following proven management paradigms (e.g. early diagnosis and treat-to-target), addressing modifiable risk factors, and considering enrolment in novel trials.

Neurokinin receptors and their implications in various autoimmune diseases

Neurokinin receptors belong to the GPCRs family and are ubiquitously expressed throughout the nervous and immune systems. Neurokinin receptors in coordination with neurokinins playing an important role in many physiological processes, including smooth muscle contraction, secretion, proliferation, and nociception. They also contribute to various disease conditions such as inflammatory bowel disease, rheumatoid arthritis, multiple sclerosis, psoriasis, and cancer. Neurokinin receptors antagonist are potent and highly selective and showing success in treating chemotherapy-induced nausea and vomiting. In this review, discuss the various neurokinin receptor expression on immune cells and their importance in various inflammatory and autoimmune diseases and their therapeutic importance.

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The Neurokinin receptor is an important regulatory mechanism to control the neuronal and immune systems.

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Various neurokinin receptors (NK1R, NK2R, and NK3R) are expressed in neurons and cells of the immune system.

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Substance P (SP) controls the differentiation and function of immune cells.

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SP-NK1R receptor signaling shows substantial cross-talk between neuronal and immune systems in inflammation and autoimmunity.

Suppressive Effects of a Truncated Inhibitor K562 Protein-Derived Peptide on Two Proinflammatory Cytokines, IL-17 and TNF-α

Inhibitor K562 (IK) protein was first isolated from the culture medium of K562 cells, a leukemia cell line, and is an inhibitory regulator of interferon-γ-induced major histocompatibility complex class II expression. Recently, exogenous truncated IK (tIK) protein showed potential as a therapeutic agent for inflammation-related diseases. In this study, we designed a novel putative anti-inflammatory peptide derived from tIK protein based on homology modeling of the human interleukin-10 (hIL-10) structure, and investigated whether the peptide exerted inhibitory effects against proinflammatory cytokines such as IL-17 and tumor necrosis factor-α (TNF-α). The peptide contains key residues involved in binding hIL-10 to the IL-10 receptor, and exerted strong inhibitory effects on IL- 17 (43.8%) and TNF-α (50.7%). In addition, we used circular dichroism spectroscopy to confirm that the peptide is usually present in a random coil configuration in aqueous solution. In terms of toxicity, the peptide was found to be biologically safe. The mechanisms by which the short peptide derived from human tIK protein exerts inhibitory effects against IL-17 and TNF-α should be explored further. We also evaluated the feasibility of using this novel peptide in skincare products.

Epithelial processed Mycobacterium avium subsp. paratuberculosis induced prolonged Th17 response and suppression of phagocytic maturation in bovine peripheral blood mononuclear cells

Johne’s disease (JD) caused by Mycobacterium avium subsp. paratuberculosis (MAP) is a chronic, wasting infectious disease in ruminants that causes enormous economic losses to the dairy and beef cattle industries. Understanding the mechanism of persistency of MAP is key to produce novel ideas for the development of new diagnostic methods or prevention techniques. We sought interactions between the host and MAP using epithelial passage model, which mimic initial stage of infection. From the transcriptomic analysis of bovine immune cells (PBMCs), it was suggested that infection through the epithelial cells elicited prolonged Th17-derived immune response, as indicated by upregulation of IL-17A, IL-17F and RORC until 120 h p.i., compared to directly infected PBMCs. Global downregulation of gene expression was observed after 72 h p.i., especially for genes encoding cell surface receptors of phagocytic cells, such as Toll-like receptors and MHC class II molecules. In addition, the cholesterol efflux transporters ABCA1, ABCG1, and APOE, which are regulated by the LXR/RXR pathway, were downregulated. In summary, it would be suggested that the host initiate immune response to activate Th17-derived cytokines, and MAP survives persistently by altering the host adaptive immune response by suppressing surface receptors and manipulating lipid metabolism in phagocytic cells.

Flare-up of cytokines in rheumatoid arthritis and their role in triggering depression: Shared common function and their possible applications in treatment (Review)

Chronic illnesses are associated with an increased risk of depression and anxiety. Rheumatoid arthritis (RA) is a chronic autoimmune disease that typically causes damage to the joints. RA extensively impacts patients, both physically and psychologically. Depression is a common comorbid disorder with RA, which leads to worsened health outcomes. There are several cytokines that are active in the joints of patients with RA. Inflammatory cytokines serve important roles in the key processes in the joints, which usually cause inflammation, articular damage and other comorbidities associated with RA. The key role of inflammatory cytokines could be attributed to their interactions within signaling pathways. In RA, IL-1, and the cytokines of TNF-α, IL-6 and IL-18 are primarily involved. Furthermore, depression is hypothesized to be strongly associated with systemic inflammation, particularly with dysregulation of the cytokine network. The present review summarizes the current state of knowledge on these two diseases from the perspective of inflammation and cytokines, and emphasizes the possible bridge between them by exploring the involvement of systemic cytokines in both conditions.

M-134, a novel HDAC6-selective inhibitor, markedly improved arthritic severity in a rodent model of rheumatoid arthritis when combined with tofacitinib

BACKGROUND

Although tofacitinib has shown highly significant efficacy for rheumatoid arthritis (RA), there are still a considerable number of patients that are non-responders owing to its limited effectiveness and various adverse effects. Thus, alternative options with better efficacy and lower toxicity are desired. Here, M-134, a recently developed HDAC6 inhibitor, was examined for its therapeutic potential when combined with tofacitinib in a rat model of RA.

METHODS

The single or combined administration of M-134 and tofacitinib was examined in complete Freund's adjuvant-induced arthritis (AIA) or collagen-induced arthritis (CIA) rodent models. To evaluate the therapeutic and adverse effects, the following factors were observed: macroscopic or microscopic scoring of all four paws; the expression of ICAM-1, VCAM-1, and IP-10 in the joints and that of various cytokines and chemokines in the plasma; the weight of the thymus and the liver; and changes in hematological enzymes.

RESULTS

Combination treatment showed strong synergistic effects as measured by the clinical score and histological changes, without adverse effects such as weight loss in the thymus and increased liver enzymes (ALT and AST). Additionally, it also reduced ICAM-1, VCAM-1, and IP-10 expression in the joints, and M-134 increased the efficacy of tofacitinib by regulating various cytokines, such as interleukin (IL)-1β, IL-17, and TNF-α, in the serum of AIA rats. Differences in the cytokine expression for each drug were found in the CIA model.

CONCLUSIONS

M-134 and tofacitinib combination therapy is a potential option for the treatment of RA through the regulation of cytokines, chemokines, and adhesion molecules.

The Role of the IL-23/IL-17 Pathway in the Pathogenesis of Spondyloarthritis

Spondyloarthritis (SpA) is a subset of seronegative rheumatic-related autoimmune diseases that consist of ankylosing spondylitis (AS), psoriatic spondylitis (PsA), reactive spondylitis (re-SpA), inflammatory bowel disease (IBD)-associated spondylitis, and unclassifiable spondylitis. These subsets share clinical phenotypes such as joint inflammation and extra-articular manifestations (uveitis, IBD, and psoriasis [Ps]). Inflammation at the enthesis, where ligaments and tendons attach to bones, characterizes and distinguishes SpA from other types of arthritis. Over the past several years, genetic, experimental, and clinical studies have accumulated evidence showing that the IL-23/IL-17 axis plays a critical role in the pathogenesis of SpA. These discoveries include genetic association and the identification of IL-23- and IL-17-producing cells in the tissue of mouse models and human patients. In this review, we summarize the current knowledge of the pathomechanism by focusing on the IL-23/IL-17 pathway and examine the recent clinical studies of biological agents targeting IL-23 and IL-17 in the treatment of SpA.

JAK-Inhibitors for the Treatment of Rheumatoid Arthritis: A Focus on the Present and an Outlook on the Future

Janus kinase inhibitors (JAKi) belong to a new class of oral targeted disease-modifying drugs which have recently revolutionized the therapeutic panorama of rheumatoid arthritis (RA) and other immune-mediated diseases, placing alongside or even replacing conventional and biological drugs. JAKi are characterized by a novel mechanism of action, consisting of the intracellular interruption of the JAK-STAT pathway crucially involved in the immune response. The aim of this narrative review is to globally report the most relevant pharmacological features and clinical outcomes of the developed and incoming JAKi for RA, based on the available preclinical and clinical evidence. A total of 219 papers, including narrative and systematic reviews, randomized controlled trials (RCTs), observational studies, case reports, guidelines, and drug factsheets, were selected. The efficacy and safety profile of both the first generation JAKi (baricitinib and tofacitinib) and the second generation JAKi (upadacitinib, filgotinib, peficitinib, decernotinib and itacitinib) were compared and discussed. Results from RCTs and real-life data are encouraging and outline a rapid onset of the pharmacologic effects, which are maintained during the time. Their efficacy and safety profile are comparable or superior to those of biologic agents and JAKi proved to be efficacious when given as monotherapy. Finally, the manufacturing of JAKi is relatively easier and cheaper than that of biologics, thus increasing the number of compounds being formulated and tested for clinical use.

Evaluating the preventive and curative effects of Toxocara canis larva in Freund's complete adjuvant-induced arthritis

Helminthic infection and the parallel host immune reactions are the results of a protracted dynamic co-interaction between the host and worms. An assessment of the effect of Toxocara canis infection on arthritis in rats stimulated by Freund's complete adjuvant (FCA) was the main purpose of the investigation. An arthritis model was established by the administration of 0.1 mL FCA in the palmar surface. Cytokine assessment, evaluating oedema and the use of a rheumatoid arthritis (RA) score provided evidence of the protective effects of T canis against adjuvant-induced arthritis (AIA). The cytokines TGF-β, IFN-ɣ, IL-10 and IL-17 were measured to assess the anti-inflammatory effect of T canis infection. Besides, arthritis swelling findings were evaluated in rat paws. The data showed that T canis infection significantly modulated the immune response by alleviating inflammatory cytokines and increasing TGF-β as an anti-inflammatory cytokine. Evaluations of arthritis swelling showed low severity and faster recuperation. These findings suggest that the products derived from T canis eggs might be a potential therapeutic candidate to treat autoimmune diseases like the arthritis.

Anti-Citrullinated Protein Antibodies in Patients with Rheumatoid Arthritis: Biological Effects and Mechanisms of Immunopathogenesis

Individuals with high anti-citrullinated protein antibody (ACPA) titers have an increased risk of developing rheumatoid arthritis (RA). Although our knowledge of the generation and production of ACPAs has continuously advanced during the past decade, our understanding on the pathogenic mechanisms of how ACPAs interact with immune cells to trigger articular inflammation is relatively limited. Citrullination disorders drive the generation and maintenance of ACPAs, with profound clinical significance in patients with RA. The loss of tolerance to citrullinated proteins, however, is essential for ACPAs to exert their pathogenicity. N-linked glycosylation, cross-reactivity and the structural interactions of ACPAs with their citrullinated antigens further direct their biological functions. Although questions remain in the pathogenicity of ACPAs acting as agonists for a receptor-mediated response, immune complex (IC) formation, complement system activation, crystallizable fragment gamma receptor (FcγR) activation, cross-reactivity to joint cartilage and neutrophil extracellular trap (NET)-related mechanisms have all been suggested recently. This paper presents a critical review of the characteristics and possible biological effects and mechanisms of the immunopathogenesis of ACPAs in patients with RA.