IL-25 regulates Th17 function in autoimmune inflammation

Immunopathogenesis of multiple sclerosis: molecular and cellular mechanisms and new immunotherapeutic approaches

BACKGROUND

Multiple sclerosis (MS) is a central nervous system (CNS) demyelinating autoimmune disease with increasing global prevalence. It predominantly affects females, especially those of European descent. The interplay between environmental factors and genetic predisposition plays a crucial role in MS etiopathogenesis.

METHODS

We searched recent relevant literature on reputable databases, which include, PubMed, Embase, Web of Science, Scopus, and ScienceDirect using the following keywords: multiple sclerosis, pathogenesis, autoimmunity, demyelination, therapy, and immunotherapy.

RESULTS

Various animal models have been employed to investigate the MS etiopathogenesis and therapeutics. Autoreactive T cells within the CNS recruit myeloid cells through chemokine expression, leading to the secretion of inflammatory cytokines driving the MS pathogenesis, resulting in demyelination, gliosis, and axonal loss. Key players include T cell lymphocytes (CD4+ and CD8+), B cells, and neutrophils. Signaling dysregulation in inflammatory pathways and the immunogenetic basis of MS are essential considerations for any successful therapy to MS. Data indicates that B cells and neutrophils also have significant roles in MS, despite the common belief that T cells are essential. High neutrophil-to-lymphocyte ratios correlate with MS severity, indicating their contribution to disease progression. Dysregulated signaling pathways further exacerbate MS progression.

CONCLUSION

MS remains incurable, but disease-modifying therapies, monoclonal antibodies, and immunomodulatory drugs offer hope for patients. Research on the immunogenetics and immunoregulatory functions of gut microbiota is continuing to provide light on possible treatment avenues. Understanding the complex interplay between genetic predisposition, environmental factors, and immune dysregulation is critical for developing effective treatments for MS.

Role of Interleukin-17 family cytokines in disease severity of patients with knee osteoarthritis

BACKGROUND

Interleukin-17 (IL-17) family plays a role in the pathogenesis of knee osteoarthritis (KOA) by contributing to the inflammatory and destructive processes in the affected joint. This study aimed to measure levels of IL-17 A and IL-25 (IL-17E) in serum of KOA patients and determine their roles in the disease severity of patients.

METHODS

In this, 34 patients with KOA and 30 age and sex-matched healthy subjects (HS) were enrolled. Patients were categorized based on their Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Visual Analog Scale (VAS), and Body Mass Index (BMI) scores. The enzyme-linked immunosorbent assay (ELISA) technique was employed to measure serum levels of IL-17 A and IL-25.

RESULTS

Level of IL-25 was significantly higher (P < 0.0001) in the KOA subjects than HS. IL-17 A level was significantly higher in KOA cases with WOMAC < 40 (P < 0.0001) in comparison to HS. IL-25 level was significantly higher in the KOA cases with WOMAC < 40 (P < 0.0001) and with WOMAC ≥ 40 (P < 0.0001) compared to HS. IL-17 A concentration was significantly higher in the KOA cases with VAS < 5 (P < 0.0001) compared to HS. IL-25 level was significantly higher in the KOA cases with VAS < 5 (P < 0.0001) and with VAS ≥ 5 (P < 0.0001) in comparison to HS. KOA patients with BMI ≥ 30 had significantly higher IL-17 A and IL-25 concentration in comparison to HS.

CONCLUSIONS

The serum level of IL-25 in KOA patients is increased probably due to negative controlling feedback on inflammatory responses, which can be associated with obesity and disease activity.

Targeting Interleukin-17 as a Novel Treatment Option for Fibrotic Diseases

Fibrosis is the end result of persistent inflammatory responses induced by a variety of stimuli, including chronic infections, autoimmune reactions, and tissue injury. Fibrotic diseases affect all vital organs and are characterized by a high rate of morbidity and mortality in the developed world. Until recently, there were no approved antifibrotic therapies. In recent years, high levels of interleukin-17 (IL-17) have been associated with chronic inflammatory diseases with fibrotic complications that culminate in organ failure. In this review, we provide an update on the role of IL-17 in fibrotic diseases, with particular attention to the most recent lines of research in the therapeutic field represented by the epigenetic mechanisms that control IL-17 levels in fibrosis. A better knowledge of the IL-17 signaling pathway implications in fibrosis could design new strategies for therapeutic benefits.

Serum cytokine profiles in myasthenia gravis with anti-muscle-specific kinase antibodies

This study measured the serum levels of of 15 cytokines in 15 patients with anti-muscle-specific kinase antibody-positive MG (MuSK-MG) using a multiplex suspension array system. Fifteen patients with non-inflammatory neurological diseases served as controls. Compared with controls, patients with MuSK-MG showed higher levels of Th1- (IFN-γ), Th2- (IL-25, IL-31, and IL-33), Th17- (IL-22), Treg-related cytokines (IL-10), and soluble CD40 ligand (sCD40L). Higher serum Th2-related cytokines (IL-25 and IL-31) levels were correlated with less MG Foundation of America (MGFA) class. These suggest that Th2-related cytokines have protective effects, whereas sCD40L and others may facilitate the disease.

Type 2 immunity in the brain and brain borders

Recent research in neuroimmunology has revolutionized our understanding of the intricate interactions between the immune system and the central nervous system (CNS). The CNS, an "immune-privileged organ", is now known to be intimately connected to the immune system through different cell types and cytokines. While type 2 immune responses have traditionally been associated with allergy and parasitic infections, emerging evidence suggests that these responses also play a crucial role in CNS homeostasis and disease pathogenesis. Type 2 immunity encompasses a delicate interplay among stroma, Th2 cells, innate lymphoid type 2 cells (ILC2s), mast cells, basophils, and the cytokines interleukin (IL)-4, IL-5, IL-13, IL-25, TSLP and IL-33. In this review, we discuss the beneficial and detrimental roles of type 2 immune cells and cytokines in CNS injury and homeostasis, cognition, and diseases such as tumors, Alzheimer's disease and multiple sclerosis.

Risk of Inflammatory Bowel Disease in Patients With Atopic Dermatitis

Importance

Data on the association between atopic dermatitis (AD) and inflammatory bowel disease (IBD) are inconsistent. Few studies have examined the association of AD or AD severity with risk of ulcerative colitis (UC) and Crohn disease (CD) separately.

Objectives

To examine the risk of new-onset IBD, UC, and CD in children and adults with AD.

Design, Setting, and Participants

This population-based cohort study assessed patients with AD matched with up to 5 controls on age, practice, and index date. Treatment exposure was used as a proxy for AD severity. Data were retrieved from The Health Improvement Network, a UK electronic medical record database, for January 1, 1994, to February 28, 2015. Data analysis was performed from January 8, 2020, to June 30, 2023.

Main Outcomes and Measures

Outcomes of interest were incident IBD, UC, and CD. Logistic regression was used to examine the risk for each outcome in children and adults with AD compared with controls.

Results

A total of 1 809 029 pediatric controls were matched to 409 431 children with AD (93.2% mild, 5.5% moderate, and 1.3% severe). The pediatric cohort ranged in median age from 4 to 5 years (overall range, 1-10 years), was predominantly male (936 750 [51.8%] controls, 196 996 [51.6%] with mild AD, 11 379 [50.7%] with moderate AD, and 2985 [56.1%] with severe AD), and with similar socioeconomic status. A total of 2 678 888 adult controls were matched to 625 083 adults with AD (65.7% mild, 31.4% moderate, and 2.9% severe). The adult cohort ranged in median age from 45 to 50 years (overall range, 30-68 years) and was predominantly female (1 445 589 [54.0%] controls, 256 071 [62.3%] with mild AD, 109 404 [55.8%] with moderate AD, and 10 736 [59.3%] with severe AD). In fully adjusted models, children with AD had a 44% increased risk of IBD (hazard ratio [HR], 1.44; 95% CI, 1.31-1.58) and a 74% increased risk of CD (HR, 1.74; 95% CI, 1.54-1.97), which increased with worsening AD; however, they did not have increased risk of UC (HR, 1.09; 95% CI, 0.94-1.27) except for those with severe AD (HR, 1.65; 95% CI, 1.02-2.67). Adults with AD had a 34% (HR, 1.34; 95% CI, 1.27-1.40) increased risk of IBD, a 36% (HR, 1.36; 95% CI, 1.26-1.47) increased risk of CB, and a 32% (HR, 1.32; 95% CI, 1.24-1.41) increased risk of UC, with risk increasing with worsening AD.

Conclusion and Relevance

In this cohort study, children and adults with AD had an increased risk of IBD, with risk varying by age, AD severity, and IBD subtype. These findings provide new insights into the association between AD and IBD. Clinicians should be aware of these risks, particularly when selecting systemic treatments for AD in patients who may have coincident gastrointestinal symptoms.

The Interleukine-17 Cytokine Family: Role in Development and Progression of Spondyloarthritis, Current and Potential Therapeutic Inhibitors

Spondyloarthritis (SpA) encompasses a group of chronic inflammatory rheumatic diseases with a predilection for the spinal and sacroiliac joints, which include axial spondyloarthritis, psoriatic arthritis, reactive arthritis, arthritis associated with chronic inflammatory bowel disease, and undifferentiated spondyloarthritis. The prevalence of SpA in the population varies from 0.5 to 2%, most commonly affecting young people. Spondyloarthritis pathogenesis is related to the hyperproduction of proinflammatory cytokines (TNFα, IL-17A, IL-23, etc.). IL-17A plays a key role in the pathogenesis of spondyloarthritis (inflammation maintenance, syndesmophites formation and radiographic progression, enthesites and anterior uveitis development, etc.). Targeted anti-IL17 therapies have established themselves as the most efficient therapies in SpA treatment. The present review summarizes literature data on the role of the IL-17 family in the pathogenesis of SpA and analyzes existing therapeutic strategies for IL-17 suppression with monoclonal antibodies and Janus kinase inhibitors. We also consider alternative targeted strategies, such as the use of other small-molecule inhibitors, therapeutic nucleic acids, or affibodies. We discuss advantages and pitfalls of these approaches and the future prospects of each method.

New insights into the function of Interleukin-25 in disease pathogenesis

Interleukin-25 (IL-25), also known as IL-17E, is a cytokine belonging to the IL-17 family. IL-25 is abundantly expressed by Th2 cells and various kinds of epithelial cells. IL-25 is an alarm signal generated upon cell injury or tissue damage to activate immune cells through the interaction with IL-17RA and IL-17RB receptors. The binding of IL-25 to IL-17RA/IL-17RB complex not only initiates and maintains type 2 immunity but also regulates other immune cells (e.g., macrophages and mast cells) via various signaling pathways. It has been well-documented that IL-25 is critically involved in the development of allergic disorders (e.g., asthma). However, the roles of IL-25 in the pathogenesis of other diseases and the underlying mechanisms are still unclear. This review presents current evidence on the roles of IL-25 in cancers, allergic disorders, and autoimmune diseases. Moreover, we discuss the unanswered key questions underlying IL-25-mediated disease pathology, which will provide new insights into the targeted therapy of this cytokine in clinical treatment.

Treatment with the Olive Secoiridoid Oleacein Protects against the Intestinal Alterations Associated with EAE

Multiple sclerosis (MS) is a CNS inflammatory demyelinating disease. Recent investigations highlight the gut-brain axis as a communication network with crucial implications in neurological diseases. Thus, disrupted intestinal integrity allows the translocation of luminal molecules into systemic circulation, promoting systemic/brain immune-inflammatory responses. In both, MS and its preclinical model, the experimental autoimmune encephalomyelitis (EAE) gastrointestinal symptoms including "leaky gut" have been reported. Oleacein (OLE), a phenolic compound from extra virgin olive oil or olive leaves, harbors a wide range of therapeutic properties. Previously, we showed OLE effectiveness preventing motor defects and inflammatory damage of CNS tissues on EAE mice. The current studies examine its potential protective effects on intestinal barrier dysfunction using MOG_35-55-induced EAE in C57BL/6 mice. OLE decreased EAE-induced inflammation and oxidative stress in the intestine, preventing tissue injury and permeability alterations. OLE protected from EAE-induced superoxide anion and accumulation of protein and lipid oxidation products in colon, also enhancing its antioxidant capacity. These effects were accompanied by reduced colonic IL-1β and TNFα levels in OLE-treated EAE mice, whereas the immunoregulatory cytokines IL-25 and IL-33 remained unchanged. Moreover, OLE protected the mucin-containing goblet cells in colon and the serum levels of iFABP and sCD14, markers that reflect loss of intestinal epithelial barrier integrity and low-grade systemic inflammation, were significantly reduced. These effects on intestinal permeability did not draw significant differences on the abundance and diversity of gut microbiota. However, OLE induced an EAE-independent raise in the abundance of Akkermansiaceae family. Consistently, using Caco-2 cells as an in vitro model, we confirmed that OLE protected against intestinal barrier dysfunction induced by harmful mediators present in both EAE and MS. This study proves that the protective effect of OLE in EAE also involves normalizing the gut alterations associated to the disease.

Could IL-25 be a potential therapeutic target for intestinal inflammatory diseases?

As a member of the IL-17 cytokine family, IL-25 (also called IL-17E) induces and sustains type 2 immunity. IL-25, which is mainly produced by intestinal epithelial cells, has been gradually investigated in recent years for its function in intestinal inflammation but is not yet fully understood. This review summarizes the expression and function of IL-25 in the intestine, especially the progression of its regulatory role on type 2 immunity-related cells. Finally, we discuss the dual role of IL-25 based on inflammatory bowel disease to inform research on targeting IL-25 for the treatment of intestinal inflammatory diseases.

Tumor-Infiltrating T Cells in EBV-Associated Gastric Carcinomas Exhibit High Levels of Multiple Markers of Activation, Effector Gene Expression, and Exhaustion

Epstein-Barr virus (EBV) is a gamma-herpesvirus associated with 10% of all gastric cancers (GCs) and 1.5% of all human cancers. EBV-associated GCs (EBVaGCs) are pathologically and clinically distinct entities from EBV-negative GCs (EBVnGCs), with EBVaGCs exhibiting differential molecular pathology, treatment response, and patient prognosis. However, the tumor immune landscape of EBVaGC has not been well explored. In this study, a systemic and comprehensive analysis of gene expression and immune landscape features was performed for both EBVaGC and EBVnGC. EBVaGCs exhibited many aspects of a T cell-inflamed phenotype, with greater T and NK cell infiltration, increased expression of immune checkpoint markers (BTLA, CD96, CTLA4, LAG3, PD1, TIGIT, and TIM3), and multiple T cell effector molecules in comparison with EBVnGCs. EBVaGCs also displayed a higher expression of anti-tumor immunity factors (PDL1, CD155, CEACAM1, galectin-9, and IDO1). Six EBV-encoded miRNAs (miR-BARTs 8-3p, 9-5p, 10-3p, 22, 5-5p, and 14-3p) were strongly negatively correlated with the expression of immune checkpoint receptors and multiple markers of anti-tumor immunity. These profound differences in the tumor immune landscape between EBVaGCs and EBVnGCs may help explain some of the observed differences in pathological and clinical outcomes, with an EBV-positive status possibly being a potential biomarker for the application of immunotherapy in GC.

Role of Th17 and IL-17 Cytokines on Inflammatory and Auto-immune Diseases

BACKGROUND

The IL-17 (interleukin 17) family consists of six structurally related pro-inflammatory cytokines, namely IL-17A to IL-17F. These cytokines have garnered significant scientific interest due to their pivotal role in the pathogenesis of various diseases. Notably, a specific subset of T-cells expresses IL-17 family members, highlighting their importance in immune responses against microbial infections.

INTRODUCTION

IL-17 cytokines play a critical role in host defense mechanisms by inducing cytokines and chemokines, recruiting neutrophils, modifying T-cell differentiation, and stimulating the production of antimicrobial proteins. Maintaining an appropriate balance of IL-17 is vital for overall health. However, dysregulated production of IL-17A and other members can lead to the pathogenesis of numerous inflammatory and autoimmune diseases.

METHOD

This review provides a comprehensive overview of the IL-17 family and its involvement in several inflammatory and autoimmune diseases. Relevant literature and research studies were analyzed to compile the data presented in this review.

RESULTS

IL-17 cytokines, particularly IL-17A, have been implicated in the development of various inflammatory and autoimmune disorders, including multiple sclerosis, Hashimoto's thyroiditis, systemic lupus erythematosus, pyoderma gangrenosum, autoimmune hepatic disorders, rheumatoid arthritis, psoriasis, psoriatic arthritis, ankylosing spondylitis, osteoarthritis, and graft-versus-host disease. Understanding the role of IL-17 in these diseases is crucial for developing targeted therapeutic strategies.

CONCLUSION

The significant involvement of IL-17 cytokines in inflammatory and autoimmune diseases underscores their potential as therapeutic targets. Current treatments utilizing antibodies against IL-17 cytokines and IL-17RA receptors have shown promise in managing these conditions. This review consolidates the understanding of IL-17 family members and their roles, providing valuable insights for the development of novel immunomodulators to effectively treat inflammatory and autoimmune diseases.

Pathogenesis-oriented therapy of psoriasis using biologics

INTRODUCTION

Psoriasis is currently regarded an immune-mediated inflammatory disease. The central pathogenic axis comprises interleukin-23, TH17-lymphocytes differentiating under its influence, and interleukin-17A as a key effector cytokine of these T-lymphocytes. All of these can selectively be targeted using biological therapies, thus potentially increasing efficacy and reducing adverse events when compared to conventional systemic therapeutics.

AREAS COVERED

We review the current concept of psoriasis as an immune-mediated inflammatory disease, assessing the evidence for a role of elements of the innate and adaptive immune system. We then correlate the pharmacological effects of biologics in psoriasis in light of the known physiologic as well as pathophysiological role of the respective targets. This is done on the basis of an extensive literature search of publications since 2018 which describe the role of the above-mentioned elements in health and disease or the effects of blocking these as an attempt to treat psoriasis.

EXPERT OPINION

Biologics targeting the above-mentioned central pathogenic axis provide a particularly effective and safe way to treat psoriasis. Given the impact of comorbidities on therapeutic decision-making, and the efficacy of some biologics also on certain comorbidities, these drugs represent a first step toward personalized medicine in the management of psoriasis.

Emerging roles for IL-25 and IL-33 in colorectal cancer tumorigenesis

Colorectal cancer (CRC) is the second leading cause of cancer-related death worldwide, and is largely refractory to current immunotherapeutic interventions. The lack of efficacy of existing cancer immunotherapies in CRC reflects the complex nature of the unique intestinal immune environment, which serves to maintain barrier integrity against pathogens and harmful environmental stimuli while sustaining host-microbe symbiosis during homeostasis. With their expression by barrier epithelial cells, the cytokines interleukin-25 (IL-25) and IL-33 play key roles in intestinal immune responses, and have been associated with inappropriate allergic reactions, autoimmune diseases and cancer pathology. Studies in the past decade have begun to uncover the important roles of IL-25 and IL-33 in shaping the CRC tumour immune microenvironment, where they may promote or inhibit tumorigenesis depending on the specific CRC subtype. Notably, both IL-25 and IL-33 have been shown to act on group 2 innate lymphoid cells (ILC2s), but can also stimulate an array of other innate and adaptive immune cell types. Though sometimes their functions can overlap they can also produce distinct phenotypes dependent on the differential distribution of their receptor expression. Furthermore, both IL-25 and IL-33 modulate pathways previously known to contribute to CRC tumorigenesis, including angiogenesis, tumour stemness, invasion and metastasis. Here, we review our current understanding of IL-25 and IL-33 in CRC tumorigenesis, with specific focus on dissecting their individual function in the context of distinct subtypes of CRC, and the potential prospects for targeting these pathways in CRC immunotherapy.

The potential roles of interleukin-25 in infectious diseases

Interleukin-25 (IL-25), also known as IL-17E, is a recently identified cytokine of the IL-17 family. Numerous studies illustrated that the expression of IL-25 is regulated by multiple pathogens, including parasitic, viral, and bacterial infections. IL-25 has a dual function in infectious diseases. On the one hand, IL-25 activates type 2 immunity via the relevant cytokines, including IL-4, IL-5, and IL-13, which are associated with the development of pathogenic infection-related allergic diseases. On the other hand, IL-25 involves in the recruitment of group 2 innate lymphoid cells (ILC2) to enhanced T helper 2 (Th2) cell differentiation, which are important to the clearance of pathogens. However, the precise roles of IL-25 in infectious diseases remain largely unknown. Thus, the current review will shed light on the pivotal roles of IL-25 in infectious diseases.

Pro- and anti-inflammatory bioactive lipids imbalance contributes to the pathobiology of autoimmune diseases

Autoimmune diseases are driven by T_H17 cells that secrete pro-inflammatory cytokines, especially IL-17. Under normal physiological conditions, autoreactive T cells are suppressed by TGF-β and IL-10 secreted by microglia and dendritic cells. When this balance is upset due to injury, infection and other causes, leukocyte recruitment and macrophage activation occurs resulting in secretion of pro-inflammatory IL-6, TNF-α, IL-17 and PGE2, LTs (leukotrienes) accompanied by a deficiency of anti-inflammatory LXA4, resolvins, protecting, and maresins. PGE2 facilitates T_H1 cell differentiation and promotes immune-mediated inflammation through T_H17 expansion. There is evidence to suggest that autoimmune diseases can be suppressed by anti-inflammatory bioactive lipids LXA4, resolvins, protecting, and maresins. These results imply that systemic and/or local application of LXA4, resolvins, protecting, and maresins and administration of their precursors AA/EPA/DHA could form a potential therapeutic approach in the prevention and treatment of autoimmune diseases.

Alarmin Cytokines as Central Regulators of Cutaneous Immunity

Skin acts as the primary interface between the body and the environment. The skin immune system is composed of a complex network of immune cells and factors that provide the first line of defense against microbial pathogens and environmental insults. Alarmin cytokines mediate an intricate intercellular communication between keratinocytes and immune cells to regulate cutaneous immune responses. Proper functions of the type 2 alarmin cytokines, thymic stromal lymphopoietin (TSLP), interleukin (IL)-25, and IL-33, are paramount to the maintenance of skin homeostasis, and their dysregulation is commonly associated with allergic inflammation. In this review, we discuss recent findings on the complex regulatory network of type 2 alarmin cytokines that control skin immunity and highlight the mechanisms by which these cytokines regulate skin immune responses in host defense, chronic inflammation, and cancer.

Interleukin 17, the double-edged sword in atherosclerosis

Cardiovascular diseases, including atherosclerosis, are the number one cause of death worldwide. These diseases have taken the place of pneumonia and other infectious diseases in the epidemiological charts. Thus, their importance should not be underestimated. Atherosclerosis is an inflammatory disease. Therefore, immunological signaling molecules and immune cells carry out a central role in its etiology. One of these signaling molecules is interleukin (IL)-17. This relatively newly discovered signaling molecule might have a dual role as acting both pro-atherogenic and anti-atherogenic depending on the situation. The majority of articles have discussed IL-17 and its action in atherosclerosis, and it may be a new target for the treatment of patients with this disease. In this review, the immunological basis of atherosclerosis with an emphasis on the role of IL-17 and a brief explanation of the role of IL-17 on atherosclerogenic disorders will be discussed.

The Th17 Pathway in Vascular Inflammation: Culprit or Consort?

The involvement of IL-17A in autoimmune and inflammatory diseases has prompted the development of therapeutic strategies to block the Th17 pathway. Promising results came from their use in psoriasis and in ankylosing spondylitis. IL-17A acts on various cell types and has both local and systemic effects. Considering the premature mortality observed during chronic inflammatory diseases, IL-17A action on vascular cells was studied. Both in vitro and in vivo results suggest that this cytokine favors inflammation, coagulation and thrombosis and promotes the occurrence of cardiovascular events. These observations led to study the role of IL-17A in diseases characterized by vascular inflammation, namely allograft rejection and vasculitis. Increased circulating levels of IL-17A and histological staining reveal that the Th17 pathway is involved in the pathogenesis of these diseases. Vasculitis treatment faces challenges while the use of steroids has many side effects. Regarding results obtained in giant cell arteritis with IL-6 inhibitors, a cytokine involved in Th17 differentiation, the use of anti-IL-17 is a promising strategy. However, lessons from rheumatoid arthritis and multiple sclerosis must be learnt before targeting IL-17 in vasculitis, which may be culprit, consort or both of them.

The role of Th17 cells in the pathogenesis and treatment of breast cancer

Breast cancer is a severe problem worldwide due to an increase in mortality and prevalence among women. Despite early diagnostic procedures as well as advanced therapies, more investigation is required to find new treatment targets. Various factors and mechanisms, such as inflammatory conditions, can play a crucial role in cancer progression. Among them, Th17 cells are identified as effective CD4⁺ T cells that play an essential role in autoimmune diseases and inflammation which may be associated with anti-tumor responses. In addition, Th17 cells are one of the main factors involved in cancer, especially breast cancer via the inflammatory process. In tumor immunity, the exact mechanism of Th17 cells is not entirely understood and seems to have a dual function in tumor development. Various studies have reported that cytokines secreted by Th17 cells are in close relation to cancer stem cells and tumor microenvironment. Therefore, they play a critical role in the growth, proliferation, and invasion of tumor cells. On the other hand, most studies have reported that T cells suppress the growth of tumor cells by the induction of immune responses. In patients with breast cancer compared to normal individuals, various studies have been reported that the Th17 population dramatically increases in peripheral blood which results in cancer progression. It seems that Th17 cells by creating inflammatory conditions through the secretion of cytokines, including IL-22, IL-17, TNF-α, IL-21, and IL-6, can significantly enhance breast cancer progression. Therefore, to identify the mechanisms and factors involved in the activation and development of Th17 cells, they can provide an essential role in preventing breast cancer progression. In the present review, the role of Th17 cells in breast cancer progression and its therapeutic potential was investigated.

Targeting the Epithelium-Derived Innate Cytokines: From Bench to Bedside

When epithelial cells are exposed to potentially threatening external stimuli such as allergens, bacteria, viruses, and helminths, they instantly produce "alarmin" cytokines, namely, IL-33, IL-25, and TSLP. These alarmins alert the immune system about these threats, thereby mobilizing host immune defense mechanisms. Specifically, the alarmins strongly stimulate type-2 immune cells, including eosinophils, mast cells, dendritic cells, type-2 helper T cells, and type-2 innate lymphoid cells. Given that the alarm-raising role of IL-33, IL-25, and TSLP was first detected in allergic and infectious diseases, most studies on alarmins focus on their role in these diseases. However, recent studies suggest that alarmins also have a broad range of effector functions in other pathological conditions, including psoriasis, multiple sclerosis, and cancer. Therefore, this review provides an update on the epithelium-derived cytokines in both allergic and non-allergic diseases. We also review the progress of clinical trials on biological agents that target the alarmins and discuss the therapeutic potential of these agents in non-allergic diseases.

Tuft Cells and Their Role in Intestinal Diseases

The interests in intestinal epithelial tuft cells, their basic physiology, involvement in immune responses and relevance for gut diseases, have increased dramatically over the last fifteen years. A key discovery in 2016 of their close connection to helminthic and protozoan infection has further spurred the exploration of these rare chemosensory epithelial cells. Although very sparse in number, tuft cells are now known as important sentinels in the gastrointestinal tract as they monitor intestinal content using succinate as well as sweet and bitter taste receptors. Upon stimulation, tuft cells secrete a broad palette of effector molecules, including interleukin-25, prostaglandin E2 and D2, cysteinyl leukotriene C4, acetylcholine, thymic stromal lymphopoietin, and β-endorphins, some of which with immunomodulatory functions. Tuft cells have proven indispensable in anti-helminthic and anti-protozoan immunity. Most studies on tuft cells are based on murine experiments using double cortin-like kinase 1 (DCLK1) as a marker, while human intestinal tuft cells can be identified by their expression of the cyclooxygenase-1 enzyme. So far, only few studies have examined tuft cells in humans and their relation to gut disease. Here, we present an updated view on intestinal epithelial tuft cells, their physiology, immunological hub function, and their involvement in human disease. We close with a discussion on how tuft cells may have potential therapeutic value in a clinical context.

The Role of PI3K Isoforms in Autoimmune Disease

Aberrant overactivation of the immune system can give rise to chronic and persistent self-attack, culminating in autoimmune disease. This is currently managed therapeutically using potent immunosuppressive and anti-inflammatory drugs. Class I phosphoinositide-3-kinases (PI3Ks) have been identified as ideal therapeutic targets for autoimmune diseases given their wide-ranging roles in immunological processes. Although progress has been hampered by issues such as poor drug tolerance and drug resistance, several PI3K inhibitors have now received regulatory approval with many others in development, including several intended to suppress the immune response in autoimmune and inflammatory diseases. This chapter reviews the evidence for contribution of aberrant PI3K activity to a range of autoimmune diseases (rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis and type I diabetes) and possible therapeutic application of isoform-specific PI3K inhibitors as immunosuppressive drugs.

T cell transgressions: Tales of T cell form and function in diverse disease states

Insights into T cell form, function, and dysfunction are rapidly evolving. T cells have remarkably varied effector functions including protecting the host from infection, activating cells of the innate immune system, releasing cytokines and chemokines, and heavily contributing to immunological memory. Under healthy conditions, T cells orchestrate a finely tuned attack on invading pathogens while minimizing damage to the host. The dark side of T cells is that they also exhibit autoreactivity and inflict harm to host cells, creating autoimmunity. The mechanisms of T cell autoreactivity are complex and dynamic. Emerging research is elucidating the mechanisms leading T cells to become autoreactive and how such responses cause or contribute to diverse disease states, both peripherally and within the central nervous system. This review provides foundational information on T cell development, differentiation, and functions. Key T cell subtypes, cytokines that create their effector roles, and sex differences are highlighted. Pathological T cell contributions to diverse peripheral and central disease states, arising from errors in reactivity, are highlighted, with a focus on multiple sclerosis, rheumatoid arthritis, osteoarthritis, neuropathic pain, and type 1 diabetes.

Evaluation of the Effects of 1,25VitD3 on Inflammatory Responses and IL-25 Expression

VitD3 may contribute to a successful pregnancy through modulation of immune responses, so VitD3 deficiency may have a role in the immunopathogenesis of unexplained recurrent spontaneous abortion (URSA). However, the mechanisms of immunomodulatory actions of VitD3 in decreasing the risk of recurrent spontaneous abortion have not been understood well.

Objective: The purpose of this research was to investigate the influence of 1,25VitD3 on IL-25 and related cytokines of Th17 cells including IL-17A, IL-6, and IL-23 in peripheral blood mononuclear cells of healthy women as a control group and women with unexplained recurrent spontaneous abortion.

Method: Isolation of peripheral blood mononuclear cells (PBMCs) was performed from peripheral blood of the subjects of the studied groups (20 women with URSA as a case group, and 20 control women). The effects of 1,25VitD3 (50 nM, for 24 h) on the studied parameters were evaluated and were compared to the positive and negative controls in vitro. Flow cytometry analysis was used to determine the percentages of regulatory T cells and Th17 cells. For gene expression measurement and cytokines assay, real-time PCR and ELISA were carried out.

Results: The proportion of Th17 cells in women with URSA was considerably higher than in the control group. IL-25 mRNA and protein levels in cultured PBMCs from women with URSA were lower than the controls. 1,25VitD3 increased IL-25 expressions at both the protein and mRNA levels in PBMCs from women with URSA relative to the control group. Additionally, 1,25VitD3 treatment not only significantly decreased the percentage of Th17 cells frequency but also reduced expressions of IL-6, IL-17A, and IL-23 in PBMCs from women with URSA.

Conclusion: 1,25VitD3 may diminish inflammatory responses cells via downregulation of IL-25 expression. It could be an interesting subject for future researches in the field of the immunopathology of URSA to identify molecular pathways in URSA treatment.

Interleukin-17 in Liver Disease Pathogenesis

Interleukin 17A (IL-17A)-producing T helper 17 (Th17) cells were identified as a subset of T helper cells that play a critical role in host defense against bacterial and fungal pathogens. Th17 cells differentiate from Th0 naïve T-cells in response to transforming growth factor β1 (TGF-β1) and IL-6, the cytokines which also drive development of liver fibrosis, require activation of transcription factor retinoic acid receptor-related orphan nuclear receptor gamma t (RORγt). IL-17A signals through the ubiquitously expressed receptor IL-17RA. Expression of IL-17RA is upregulated in patients with hepatitis B virus/hepatitis C virus (HBV/HCV) infections, nonalcoholic steatohepatitis (NASH), alcohol-associated liver disease (AALD), hepatocellular carcinoma (HCC), and experimental models of chronic toxic liver injury. The role of IL-17 signaling in the pathogenesis of NASH- and AALD-induced metabolic liver injury and HCC will be the focus of this review. The role of IL-17A-IL-17RA axis in mediation of the cross-talk between metabolically injured hepatic macrophages, hepatocytes, and fibrogenic myofibroblasts will be discussed.

Targeting the Interleukin-23/Interleukin-17 Inflammatory Pathway: Successes and Failures in the Treatment of Axial Spondyloarthritis

The IL-23/IL-17 pathway has been implicated in the etiopathogenesis of axial spondyloarthritis through studies of genetic polymorphisms associated with disease, an animal model with over-expression of IL-23 that resembles human disease, and observations that cytokines in this pathway can be found at the site of disease in both humans and animal models. However, the most direct evidence has emerged from clinical trials of agents targeting cytokines in this pathway. Monoclonal antibodies targeting IL-17A have been shown to ameliorate signs and symptoms, as well as MRI inflammation in the spine and sacroiliac joints, in patients with radiographic and non-radiographic axial spondyloarthritis. This was evident in patients refractory to non-steroidal anti-inflammatory agents as well as patients failing treatment with tumor necrosis factor inhibitor therapies. Treatment with a bispecific antibody targeting both IL-17A and IL-17F was also effective in a phase II study. Post-hoc analyses have even suggested a potential disease-modifying effect in reducing development of spinal ankylosis. However, benefits for extra-articular manifestations were limited to psoriasis and did not extend to colitis and uveitis. Conversely, trials of therapies targeting IL-23 did not demonstrate any significant impact on signs, symptoms, and MRI inflammation in axial spondyloarthritis. These developments coincide with recent observations that expression of these cytokines is evident in many different cell types with roles in innate as well as adaptive immunity. Moreover, evidence has emerged for the existence of both IL-23-dependent and IL-23-independent pathways regulating expression of IL-17, potentially associated with different roles in intestinal and axial skeletal inflammation.

Molecular biochemical aspects of salt (sodium chloride) in inflammation and immune response with reference to hypertension and type 2 diabetes mellitus

Obesity, insulin resistance, type 2 diabetes mellitus (T2DM) and hypertension (HTN) are common that are associated with low-grade systemic inflammation. Diet, genetic factors, inflammation, and immunocytes and their cytokines play a role in their pathobiology. But the exact role of sodium, potassium, magnesium and other minerals, trace elements and vitamins in the pathogenesis of HTN and T2DM is not known. Recent studies showed that sodium and potassium can modulate oxidative stress, inflammation, alter the autonomic nervous system and induce dysfunction of the innate and adaptive immune responses in addition to their action on renin-angiotensin-aldosterone system. These actions of sodium, potassium and magnesium and other minerals, trace elements and vitamins are likely to be secondary to their action on pro-inflammatory cytokines IL-6, TNF-α and IL-17 and metabolism of essential fatty acids that may account for their involvement in the pathobiology of insulin resistance, T2DM, HTN and autoimmune diseases.

Interleukin-25: New perspective and state-of-the-art in cancer prognosis and treatment approaches

Cancer is a leading cause of death which imposes a substantial financial burden. Among the several mechanisms involved in cancer progression, imbalance of immune cell‐derived factors such as cytokines and chemokines plays a central role. IL‐25, as a member of the IL‐17 cytokine subfamily, exerts a paradoxical role in cancer, including tumor supportive and tumor suppressive. Hence, we have tried to clarify the role of IL‐25 and its receptor in tumor progression and cancer prognosis. It has been confirmed that IL‐25 exerts a tumor‐suppressive role through inducing infiltration of eosinophils and B cells into the tumor microenvironment and activating the apoptotic pathways. In contrast, the tumor‐supportive function has been implemented by activating inflammatory cascades, promoting cell cycle, and inducing type‐2 immune responses. Since IL‐25 has been dysregulated in tumor tissues and this dysregulation is involved in cancer development, its examination can be used as a tumor diagnostic and prognostic biomarker. Moreover, IL‐25‐based therapeutic approaches have shown promising results in cancer inhibition. In cancers in which IL‐25 has a tumor‐suppressive function, employing IL‐25‐enhancing approaches, such as Virulizin^® and dihydrobenzofuran administration, has potentially inhibited tumor cell growth. On the other hand, in the case of IL‐25‐dependent tumor progression, using IL‐25 blocking methods, including anti‐IL‐25 antibodies, might be a complementary approach to the other anticancer agent. Collectively, it is hoped, IL‐25 might be a promising target in cancer treatment.

Roles of IL-25 in Type 2 Inflammation and Autoimmune Pathogenesis

Interleukin-17E (IL-25) is a member of the IL-17 cytokine family that includes IL-17A to IL-17F. IL-17 family cytokines play a key role in host defense responses and inflammatory diseases. Compared with other IL-17 cytokine family members, IL-25 has relatively low sequence similarity to IL-17A and exhibits a distinct function from other IL-17 cytokines. IL-25 binds to its receptor composed of IL-17 receptor A (IL-17RA) and IL-17 receptor B (IL-17RB) for signal transduction. IL-25 has been implicated as a type 2 cytokine and can induce the production of IL-4, IL-5 and IL-13, which in turn inhibits the differentiation of T helper (Th) 17. In addition to its anti-inflammatory properties, IL-25 also exhibits a pro-inflammatory effect in the pathogenesis of Th17-dominated diseases. Here, we review recent advances in the roles of IL-25 in the pathogenesis of inflammation and autoimmune diseases.

Removal of CD276+ cells from haploidentical memory T-cell grafts significantly lowers the risk of GVHD

Detrimental graft-versus-host disease (GVHD) still remains a major cause of death in hematopoietic stem cell transplantation (HSCT). The recently explored depletion of naive cells from mobilized grafts (CD45RA depletion) has shown considerable promise, yet is unable to eliminate the incidence of GVHD. Analysis of CD45RA-depleted haploidentical mixed lymphocytes culture (haplo-MLC) revealed insufficient suppression of alloresponses in the CD4⁺ compartment and identified CD276 as a marker for alloreactive memory Th1 T cells. Conclusively, depleting CD276⁺ cells from CD45RA-depleted haplo-MLC significantly attenuated alloreactivity to recipient cells while increasing antiviral reactivity and maintaining anti-third party reactivity in vitro. To evaluate these findings in vivo, bulk, CD45RA-depleted, or CD45RA/CD276-depleted CD4⁺ T cells from HLA-DR4^negative healthy humans were transplanted into NSG-Ab°DR4 mice, a sensitive human allo-GVHD model. Compellingly, CD45RA/CD276-depleted grafts from HLA-DR4^negative donors or in vivo depletion of CD276⁺ cells after transplant of HLA-DR4^negative memory CD4 T cells significantly delay the onset of GVHD symptoms and significantly alleviate its severity in NSG-Ab°DR4 mice. The clinical courses correlated with diminished Th1-cytokine secretion and downregulated CXCR6 expression of engrafted peripheral T cells. Collectively, mismatched HLA-mediated GVHD can be controlled by depleting recipient-specific CD276⁺ alloreacting T cells from the graft, highlighting its application in haplo-HSCT.

Lack of association between serum IL-25 levels and acute coronary syndrome: a preliminary study

Purpose    Here, for the first time, the possible association between IL-25 and the risk of acute coronary syndrome (ACS) in Iranian patients was investigated.Material and methods    In this study, serum IL-25 concentrations were measured with an enzyme-linked immunosorbent assay in 88 ACS patients, 40 stable angina pectoris (SAP) patients, and 50 healthy control subjects.Results    No significant differences in IL-25 concentrations were observed between SAP (340±168 ng / l), ACS (330±151 ng / l), and control (302±135 ng / l) groups (p=0.5), nor was there a difference among patients with 1, 2, or 3 vessel disease in the SAP and ACS groups. Linear regression analyses revealed that IL-25 was not correlated with coronary artery disease risk factors. Biochemical and demographic variables did not differ significantly among IL-25 quartiles.Conclusion    Despite previous murine and human studies showing a protective role of IL-25 in atherosclerosis, our results revealed that IL-25 does not have potential implications for atherosclerosis development and management in humans.

The expression of IL17RA on sputum macrophages in asthma patients

IL-17A and IL-25 (IL-17 cytokines family) play an important role in the development of asthma, and allergy. Both cytokines act by binding to heterodimeric receptors with IL17RA as a common subunit. This receptor is found on macrophages, and some other cell types. The aim of the study was to determine the expression of IL17RA on asthmatic and control macrophages from induced sputum (IS) with the regard to IL-17/IL-25 background and relation to clinical features of the disease. We found an elevated expression of IL17RA on sputum macrophages in asthma patients vs controls. A characteristic sputum profile of atopic asthmatic was as follows: high CD206 + IL17RA + macrophage percentage, elevated IL-25 level and low CD206 + IL17RA- macrophage percentage. Based on the above results, it seems that CD206 + sputum macrophages are the effector cells that express common subunit of the receptor for IL-17A and IL-25 in asthma. This may be related to the Th2-dependent environment in asthma and increased concentrations of IL-25 and IL-13 as well as eosinophils in the airways. To our knowledge, our study provides the first data on a possible link between immunological reaction orchestrating CD206 + expressing sputum macrophages and IL-25 via IL17RA pathway in the asthmatic airways.

Anhedonia and Increased Evoked Immune Response

There is a growing body of evidence supporting the association between immune processes and psychopathology, including major depressive disorder (MDD). However, lack of diagnostic specificity has given rise to a search for specific symptom types, as opposed to more heterogeneous categorical diagnoses, linked to increased inflammation. One such symptom could be anhedonia, which is not only a key feature of MDD, but also a pervasive and persistent transdiagnostic symptom. To evaluate the specific role of anhedonia as well as categorical MDD diagnoses, we examined endotoxin-evoked immune responses in vitro in relation to current levels of anhedonia and history of recurrent MDD (rMDD) in a sample of adults recruited from the community. A total of 39 participants either had a history of rMDD (n ​= ​20) or no lifetime history of any MDD episodes (n ​= ​19). The average age of participants was 36.81 years and the majority were women (87.2%) and Caucasian (76.3%). We found that higher levels of current anhedonia, but not history of rMDD, were associated with increased lipopolysaccharide-stimulated levels of inflammatory markers even after we statistically adjusted for the potential influence of participants’ demographic (age, sex, ethnicity, income) and physiological (body temperature, BMI) characteristics, current symptoms of depression and anxiety, and the time of day of the sample collection. These findings highlight the relation of anhedonia specifically, rather than rMDD more generally, with inflammatory processes and identify endotoxin-stimulated cytokine production as a plausible biological marker of current anhedonia.

Identification of Novel Serological Autoantibodies in Takayasu Arteritis Patients Using HuProt Arrays

To identify novel autoantibodies of Takayasu arteritis (TAK) using HuProt array-based approach, a two-phase approach was adopted. In Phase I, serum samples collected from 40 TAK patients, 15 autoimmune disease patients, and 20 healthy subjects were screened to identify TAK-specific autoantibodies using human protein (HuProt) arrays. In phase II, the identified candidate autoantibodies were validated with TAK-focused arrays using an additional cohort comprised of 109 TAK patients, 110 autoimmune disease patients, and 96 healthy subjects. Subsequently, the TAK-specific autoantibodies validated in phase II were further confirmed using western blot analysis. We identified and validated eight autoantibodies as potential TAK-specific diagnostic biomarkers, including anti-SPATA7, -QDPR, -SLC25A2, -PRH2, -DIXDC1, -IL17RB, -ZFAND4, and -NOLC1 antibodies, with AUC of 0.803, 0.801, 0.780, 0.696, 0.695, 0.678, 0.635, and 0.613, respectively. SPATA7 could distinguish TAK from healthy and disease controls with 73.4% sensitivity at 85.4% specificity, while QDPR showed 71.6% sensitivity at 86.4% specificity. SLC25A22 showed the highest sensitivity of 80.7%, but at lower specificity of 67.0%. In addition, PRH2, IL17RB, and NOLC1 showed good specificities of 88.3%, 85.9%, and 86.9%, respectively, but at lower sensitivities (<50%). Finally, DIXDC1 and ZFAND4 showed moderate performance as compared with the other autoantibodies. Using a decision tree model, we could reach a specificity of 94.2% with AUC of 0.843, a significantly improved performance as compared with that by each individual biomarker. The performances of three autoantibodies, namely anti-SPATA7, -QDPR, and -PRH2, were successfully confirmed with western blot analysis. Using this two-phase strategy, we identified and validated eight novel autoantibodies as TAK-specific biomarker candidates, three of which could be readily adopted in a clinical setting.

IL-25 (IL-17E) in epithelial immunology and pathophysiology

IL-25, also known as IL-17E, is a unique cytokine of the IL-17 family. Indeed, IL-25 exclusively was shown to strongly induce expression of the cytokines associated with type 2 immunity. Although produced by several types of immune cells, such as T cells, dendritic cells, or group 2 innate lymphoid cells, a vast amount of IL-25 derives from epithelial cells. The functions of IL-25 have been actively studied in the context of physiology and pathology of various organs including skin, airways and lungs, gastrointestinal tract, and thymus. Accumulating evidence suggests that IL-25 is a "barrier surface" cytokine whose expression depends on extrinsic environmental factors and when upregulated may lead to inflammatory disorders such as atopic dermatitis, psoriasis, or asthma. This review summarizes the progress of the recent years regarding the effects of IL-25 on the regulation of immune response and the balance between its homeostatic and pathogenic role in various epithelia. We revisit IL-25's general and tissue-specific mechanisms of action, mediated signaling pathways, and transcription factors activated in immune and resident cells. Finally, we discuss perspectives of the IL-25-based therapies for inflammatory disorders and compare them with the mainstream ones that target IL-17A.

Effects of smoking on the gingival crevicular fluid levels of interleukin-17A, interleukin-17E, and oxidative stress following periodontal treatment process

OBJECTIVE AND BACKGROUND

How smoking affects periodontal inflammation and healing still needs to be revealed with all its mechanisms. In this study, the gingival crevicular fluid (GCF) levels of: (a) interleukin-17A (IL-17A) and interleukin-17E(IL-17E) with their ratios and (b) oxidative stress by means of total oxidative stress (TOS), total anti-oxidant capacity (TAOC), and their ratios as the oxidative stress index (OSI) were evaluated and compared for smoking and non-smoking periodontitis patients after a periodontitis management process including both the non-surgical and surgical treatments.

MATERIALS AND METHODS

Fifteen smoker and 15 non-smoker generalized periodontitis patients as 2 distinct groups participated in the study. Conventional clinical and radiographical examinations were utilized for the periodontitis diagnosis. The clinical data and GCF samples were collected at baseline, 4 week after non-surgical periodontal treatment (NSPT), and 4 weeks after surgical periodontal treatment (SPT). IL-17A, IL-17E, TOS, and TAOC were determined by ELISA and Rel Assay.

RESULTS

Clinical parameters in both smokers and non-smokers improved following periodontal treatment (P < .001) and their clinical data were similar for all the examination times (baseline, NSPT, and SPT) (P > .05). Following the treatment phases, the IL-17A concentration decreased and the IL-17E concentration increased in both the smokers and non-smokers (P < .01). The total amount of IL-17A decreased while the total amount of IL-17E increased in smokers throughout NSPT and SPT (P < .01). Such an alteration was seen only at SPT compared to NSPT and baseline in non-smokers (P < .01). The concentration and total amount of IL-17A were higher at baseline, and the concentration and total amount of IL-17E were lower at all examination time points in non-smokers as compared to smokers (P < .01). The 17A/E ratio decreased in both groups following the treatment phases and was higher in smokers at all the examination times (P < .01). TOS were higher and TAOC were lower in smokers versus non-smokers at all the time points, but the differences were significant only for TOS levels (P < .01). Throughout the treatment phases, the concentration and total amount of TOS decreased in smokers(P < .01) and only the total amount of TOS decreased in non-smokers (P < .01). The concentration and total amounts of TAOC increased throughout the treatments in both smokers and non-smokers without significant changes (P > .05). The baseline OSI was higher in smokers, and it decreased only in smokers following the treatment phases (P < .01).

CONCLUSIONS

Smoking and periodontal inflammation were found to alter IL-17A, IL-17E, and oxidant/anti-oxidant statuses in periodontitis patients. The intra-group assessments in smokers demonstrated more apparent alterations in the oxidant/anti-oxidant statuses and IL-17A and IL-17E levels after periodontitis management.

Interleukin-25-mediated resistance against intestinal trematodes does not depend on the generation of Th2 responses

Background

The cytokine interleukin-25 (IL-25) is recognized as the most relevant initiator of protective T helper 2 (Th2) responses in intestinal helminth infections. This cytokine induces resistance against several species of intestinal helminths, including the trematode Echinostoma caproni. E. caproni has been extensively used as an experimental model to study the factors determining resistance to intestinal infections. In the study reported here, we assessed the role of IL-25 in the generation of resistance in mice infected with E. caproni.

Methods

The factors that determine the production of IL-25 in mice experimentally infected with E. caproni were determined, as were the consequences of IL-25 production in terms of polarization of the immune response and resistance to infection.

Results

Our results show that the role of IL-25 in the polarization of the immune response differs between the primary and secondary immune responses. IL-25 is required for the development of a Th2 phenotype in primary E. caproni infections, but it can also promote the differentiation to Th2 memory cell subsets that enhance type-2 immunity in memory responses. However, the development of Th2 responses does not induce resistance to infection. The Th2 phenotype does not elicit resistance, and IL-25 is responsible for the resistance regardless of its type-2 cytokine activity and activation of signal transducer and activator of transcription (STAT6). Alternative activation of macrophages induced by IL-25 can be implicated in the resistance to infection.

Conclusions

In contrast to primary infection, secondary infection elicits a type-2 immune response even in the absence of IL-25 expression. Despite the development of a type-2 response, mice are susceptible to secondary infection associated with the lack of IL-25. Resistance to infection is due to the production of IL-25, which acts autonomously from Th2 response in terms of parasite clearance.

Oleanolic acid ameliorates intestinal alterations associated with EAE

Background

Multiple sclerosis (MS) is a chronic demyelinating autoimmune disease affecting the CNS. Recent studies have indicated that intestinal alterations play key pathogenic roles in the development of autoimmune diseases, including MS. The triterpene oleanolic acid (OA), due to its anti-inflammatory properties, has shown to beneficially influence the severity of the experimental autoimmune encephalomyelitis (EAE), a preclinical model of MS. We herein investigate EAE-associated gut intestinal dysfunction and the effect of OA treatment.

Methods

Mice with MOG_35–55-induced EAE were treated with OA or vehicle from immunization day and were daily analyzed for clinical deficit. We performed molecular and histological analysis in serum and intestinal tissues to measure oxidative and inflammatory responses. We used Caco-2 and HT29-MTX-E12 cells to elucidate OA in vitro effects.

Results

We found that OA protected from EAE-induced changes in intestinal permeability and preserved the mucin-containing goblet cells along the intestinal tract.

Serum levels of the markers for intestinal barrier damage iFABP and monocyte activation sCD14 were consistently and significantly reduced in OA-treated EAE mice. Beneficial OA effects also included a decrease of pro-inflammatory mediators both in serum and colonic tissue of treated-EAE mice. Moreover, the levels of some immunoregulatory cytokines, the neurotrophic factor GDNF, and the gastrointestinal hormone motilin were preserved in OA-treated EAE mice. Regarding oxidative stress, OA treatment prevented lipid peroxidation and superoxide anion accumulation in intestinal tissue, while inducing the expression of the ROS scavenger Sestrin-3. Furthermore, short-chain fatty acids (SCFA) quantification in the cecal content showed that OA reduced the high iso-valeric acid concentrations detected in EAE-mice. Lastly, using in vitro cell models which mimic the intestinal epithelium, we verified that OA protected against intestinal barrier dysfunction induced by injurious agents produced in both EAE and MS.

Conclusion

These findings reveal that OA ameliorates the gut dysfunction found in EAE mice. OA normalizes the levels of gut mucosal dysfunction markers, as well as the pro- and anti-inflammatory immune bias during EAE, thus reinforcing the idea that OA is a beneficial compound for treating EAE and suggesting that OA may be an interesting candidate to be explored for the treatment of human MS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-020-02042-6.

The expression of interleukin-25 increases in human coronary artery disease and is associated with the severity of coronary stenosis

Objective:

Interleukin (IL) 25, also known as IL-17E, is an inflammatory cytokine and has been demonstrated to be closely related to cardiovascular diseases by regulating immunity and inflammation, including atherosclerosis. This study was aimed to evaluate the expression of IL-25 in patients with coronary artery disease (CAD).

Methods:

In this study, the expression of IL-25 in normal (n=6) and atherosclerotic (n=10) human coronary arteries was detected by immunofluorescent staining. In addition, the serum IL-25, IL-6, and tumor necrosis factor (TNF) α concentrations in stable angina pectoris (SAP, n=44), unstable angina pectoris (UAP, n=46), acute myocardial infarction (AMI, n=34), and non-CAD (control, n=36) were measured using enzyme-linked immunosorbent assay (ELISA) kits.

Results:

IL-25 was significantly increased in coronary arteries of CAD patients when compared with normal coronary arteries, with macrophages and T lymphocytes being the sources of IL-25, especially macrophages. Moreover, the serum concentrations of IL-25 were markedly elevated in CAD patients and gradually increased in SAP, UAP, and AMI groups. In addition, IL-25 levels were positively correlated with the IL-6 and TNF-α levels, and Gensini score in CAD patients. Logistic regression analysis showed that IL-25 was independently positively correlated with the occurrence of acute coronary syndrome (ACS). A receiver operator characteristic curve suggested that IL-25 presented a significant diagnosis value in ACS.

Conclusion:

IL-25 is increased in the coronary arteries and serum of CAD patients and is associated with the severity of coronary stenosis and the occurrence of ACS, suggesting that IL-25 may be one of the biomarkers of ACS. (Anatol J Cardiol 2020; 23: 151-9)

Immunopathobiology and therapeutic targets related to cytokines in liver diseases

Chronic liver injury with any etiology can progress to fibrosis and the end-stage diseases cirrhosis and hepatocellular carcinoma. The progression of liver disease is controlled by a variety of factors, including liver injury, inflammatory cells, inflammatory mediators, cytokines, and the gut microbiome. In the current review, we discuss recent data on a large number of cytokines that play important roles in regulating liver injury, inflammation, fibrosis, and regeneration, with a focus on interferons and T helper (Th) 1, Th2, Th9, Th17, interleukin (IL)-1 family, IL-6 family, and IL-20 family cytokines. Hepatocytes can also produce certain cytokines (such as IL-7, IL-11, and IL-33), and the functions of these cytokines in the liver are briefly summarized. Several cytokines have great therapeutic potential, and some are currently being tested as therapeutic targets in clinical trials for the treatment of liver diseases, which are also described.

Much More Than IL-17A: Cytokines of the IL-17 Family Between Microbiota and Cancer

The interleukin-(IL-)17 family of cytokines is composed of six members named IL-17A, IL-17B, IL-17C, IL-17D, IL-17E, and IL-17F. IL-17A is the prototype of this family, and it was the first to be discovered and targeted in the clinic. IL-17A is essential for modulating the interplay between commensal microbes and epithelial cells at our borders (i.e., skin and mucosae), and yet, for protecting us from microbial invaders, thus preserving mucosal and skin integrity. Interactions between the microbiota and cells producing IL-17A have also been implicated in the pathogenesis of immune mediated inflammatory diseases and cancer. While interactions between microbiota and IL-17B-to-F have only partially been investigated, they are by no means less relevant. The cellular source of IL-17B-to-F, their main targets, and their function in homeostasis and disease distinguish IL-17B-to-F from IL-17A. Here, we intentionally overlook IL-17A, and we focus instead on the role of the other cytokines of the IL-17 family in the interplay between microbiota and epithelial cells that may contribute to cancer pathogenesis and immune surveillance. We also underscore differences and similarities between IL-17A and IL-17B-to-F in the microbiota-immunity-cancer axis, and we highlight therapeutic strategies that directly or indirectly target IL-17 cytokines in diseases.

Interleukin-17 in rheumatoid arthritis: Trials and tribulations

Interleukin-17A (IL-17A) is a pro-inflammatory cytokine with well-characterized biological effects on stromal cell activation, angiogenesis, and osteoclastogenesis. The presence of this cytokine in the inflamed joints of patients with rheumatoid arthritis (RA), together with compelling data from in vitro and experimental arthritis models demonstrating its pro-inflammatory effects, made this cytokine a strong candidate for therapeutic targeting. Clinical trials, however, have shown relatively modest success in RA as compared with other indications. Guided by recent insights in IL-17 biology, this review aims to explore possible reasons for the limited clinical efficacy of IL-17A blockade in RA, and what we can learn from these results going forward.

TLR9-IL-2 axis exacerbates allergic asthma by preventing IL-17A hyperproduction

Allergic asthma is one of most famous allergic diseases, which develops lung and airway inflammation. Recent studies have revealed the relationship between the pathology of allergic asthma and the increase of host-derived DNA in inflamed lung, but the role of the DNA-recognizing innate immune receptor for the inflammation is unknown well. Here we investigated the role of Toll-Like Receptor 9 in the pathogenesis of allergic asthma without synthesized CpG-ODNs. To examine that, we analyzed the pathology and immunology of house-dust-mite (HDM)-induced allergic asthma in Tlr9^–/– mice and TLR9-inhibitory-antibody-treated mice. In Tlr9^–/– mice, airway hyperresponsiveness (AHR) and the number of eosinophils decreased, and production of the Th2 cytokines IL-13, IL-5, and IL-4 was suppressed, compared with in wild-type mice. Interestingly, unlike Th2 cytokine production, IL-17A production was increased in Tlr9^–/– mice. Furthermore, production of IL-2, which decreases IL-17A production, was reduced in Tlr9^–/– mice. Blockade of TLR9 by treatment with TLR9-inhibitory-antibody, NaR9, effectively suppressed the development of allergic asthma pathology. IL-17A production in NaR9-treated mice was enhanced, which is comparable to Tlr9^-/- mice. These results suggest that the TLR9–IL-2 axis plays an important role in Th2 inflammation by modulating IL-17A production in HDM-induced allergic asthma and that targeting of TLR9 might be a novel therapeutic method for allergic asthma.

Interleukin-17 and ischaemic stroke

Interleukin-17 (IL-17) is a cytokine family that includes 6 members, IL-17A through IL-17F, most of them are reported to have pro-inflammatory role. Through binding to their receptors (IL-17Rs), IL-17 activates the intracellular signalling pathways to play an important role in autoimmune diseases, including rheumatoid arthritis (RA) and multiple sclerosis (MS). Ischaemic stroke is a complex pathophysiological process mainly caused by regional cerebral ischaemia. Inflammatory factors contribute to the physiological process of stroke that leads to poor prognosis. IL-17 plays a crucial role in promoting inflammatory response and inducing secondary injury in post-stroke. Though immune cells and inflammatory factors have been reported to be involved in the damage of stroke, the functions of IL-17 in this process need to be elucidated. This review focuses on the pathological modulation and the mechanism of IL-17 family in ischaemic stroke and seeking to provide new insights for future therapies.

Interleukin-17A: The Key Cytokine in Neurodegenerative Diseases

Neurodegenerative diseases are characterized by the loss of neurons and/or myelin sheath, which deteriorate over time and cause dysfunction. Interleukin 17A is the signature cytokine of a subset of CD4⁺ helper T cells known as Th17 cells, and the IL-17 cytokine family contains six cytokines and five receptors. Recently, several studies have suggested a pivotal role for the interleukin-17A (IL-17A) cytokine family in human inflammatory or autoimmune diseases and neurodegenerative diseases, including psoriasis, rheumatoid arthritis (RA), Alzheimer’s disease (AD), Parkinson’s disease (PD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), and glaucoma. Studies in recent years have shown that the mechanism of action of IL-17A is more subtle than simply causing inflammation. Although the specific mechanism of IL-17A in neurodegenerative diseases is still controversial, it is generally accepted now that IL-17A causes diseases by activating glial cells. In this review article, we will focus on the function of IL-17A, in particular the proposed roles of IL-17A, in the pathogenesis of neurodegenerative diseases.

Estrogen Receptor Downregulates Expression of PD-1/PD-L1 and Infiltration of CD8+ T Cells by Inhibiting IL-17 Signaling Transduction in Breast Cancer

Background: The relationship between the interleukin 17 (IL-17) family of cytokines and breast cancer has been widely studied in recent years. Many studies have revealed increased levels of the cytokine IL-17A in estrogen receptor (ER)-negative or triple-negative breast cancer. Upregulation of IL-17A signaling is associated with increased expression of programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) in breast cancer with low ER expression and may elevate the infiltration of CD8⁺ T cells in tumor tissue. This study aims to determine whether ER downregulates the expression of PD-1/PD-L1, reduces the infiltration of CD8⁺ T cells, and affects the immune microenvironment by decreasing T-helper 17 (Th17) cell infiltration and inhibiting IL-17 signaling in breast cancer.

Methods: Samples in The Cancer Genome Atlas Breast Cancer dataset were grouped by ER status and the PAM50 intrinsic subtype. The expression of IL-17 family cytokines and Th17 cell signature cytokines were compared between groups. IL-17 signaling pathway-related genes that were differentially expressed according to the ER level were identified. The PD-1 and PD-L1 levels were compared between breast cancer samples with different ER statuses and IL-17A/IL-17F expression levels. Correlation analyses of the expression of PD-1/PD-L1 and IL-17 signaling pathway-related genes were performed. The associations of the expression of IL-17 signaling pathway-related genes with the immune microenvironment were investigated.

Results: High levels of ER decreased the expression of IL-17A, IL-17C, and IL-17F but increased the expression of IL-17E (IL25), which acts as a suppressor of IL-17 signaling. The expression levels of Th17 cell signature cytokines were significantly increased in ER-negative breast cancer. The expression levels of genes encoding downstream products of IL-17A/IL-17F signaling were downregulated in breast cancer with high ER expression. Increased expression of PD-1/PD-L1 was associated with ER-negative status, IL-17A-positive status, IL-17F-positive status, and upregulation of IL-17 signaling pathway-related genes in breast cancer. Enhanced IL-17 signal transduction was associated with the elevation of CD8⁺ T cell infiltration and variation of the immune microenvironment of breast cancer.

Conclusion: High estrogen receptor levels decrease PD-1/PD-L1 expression and CD8⁺ T cell infiltration by suppressing Th17 cell infiltration and IL-17 signal transduction in breast cancer.

Interleukin-25 regulates matrix metalloproteinase-2 and -9 expression in periodontal fibroblast cells through ERK and P38MAPK pathways

Interleukin-25 (IL-25) has been recognized as a new member of the IL-17 family and implicated in various inflammatory pathology. We aimed to investigate the effects of IL-25 on the expression of matrix metalloproteinase-2 (MMP-2), MMP-8, and MMP-9 in periodontal fibroblast cells (PFCs), cell migration, cytoskeleton F-actin, and to explore the involved extracellular-regulated protein kinases (ERKs), P38 mitogen-activated protein kinase (P38MAPK) signaling pathways, and IL-17 receptor. To evaluate the expression of MMP-2, MMP-8, MMP-9, and F-actin, PFCs were treated by various doses of IL-25 (0, 20, 50, 100, and 500 ng/ml). Protein expression of extracellular metalloproteinase inducer (EMMPRIN) was also evaluated by western blot. Cell scratches experiment was performed to test the cell migration ability. ERK, P38MAPK, and Jun N-terminal kinase signal pathways and related expression of P-ERK and P-P38MAPK were examined after treatment of different doses of IL-25 and after treatment of inhibitors of ERK and P38MAPK. Immunofluorescence of MMP-2, MMP-9, and F-actin were evaluated after inhibitor treatment. IL-17RB small interfering RNA was used to examine the receptor of IL-25. IL-25 increased the protein expression of MMP-2 and MMP-9. MMP-8 and EMMPRIN expressions were not regulated by IL-25 in PFCs. Positive IF staining extended strongly from the central part to the whole cell. IL-25 mediated MMP-2, MMP-9, F-actin expressions and cell migration were regulated by P38MAPK and ERK pathways, and IL-17RB. SB203580 and U0126 blocked the effects of IL-25 through the inhibition of ERK, P38MAPK, P-ERK, and P-P38MAPK. The data indicate that IL-25 could regulate cell migration, MMP-2, and MMP-9 expression, but not MMP-8 expression, in PFCs. Moreover, the regulation effects were involved in ERK and P38MAPK pathways, and receptor IL-17RB.

Role of biomarkers and effect of FIP-fve in acute and chronic animal asthma models

BACKGROUND

Asthma is a consequence of complex gene-environment interactions. Exploring the heterogeneity of asthma in different stages is contributing to our understanding of its pathogenesis and the development of new therapeutic strategies, especially in severe cases.

OBJECTIVE

This study aimed to further understand the relationship between manifestations of acute and chronic asthma and various endotypes, and explore the severity of lung inflammation, cell types, cytokine/chemokine differences, and the effects of FIP-fve.

MATERIALS AND METHODS

Acute and chronic OVA-sensitization mouse asthma models, based on our previously published method, were used and FIP-fve was used to evaluate the effect on these two models. BALF cytokines/chemokines were detected according to the manufacturer's protocol.

RESULTS

Seventeen cytokine/chemokine secretions were higher in the chronic stage than in the acute stage. Whether in acute stage or chronic stage, the FIP-fve treatment groups had reduced airway hyperresponsiveness, infiltration of airway inflammatory cells, secretion of cytokines, chemokines by Th2 cells, and TNF-α, IL-8, IL-17, CXCL-1, CXCL-10, CCL-17, and CCL-22, and it was also found that the Treg cell cytokine IL-10 had increased significantly. PCA (Principal Component Analysis) was also used to compare statistics and laboratory data to find the important biomarkers in different stages and after treatment with FIP-fve.

CONCLUSIONS

There are many different immune responses in the different stages of the asthma process. Drug treatment at the appropriate times might help reduce the worsening of asthma.