Local and systemic effects of IL-17 in joint inflammation: a historical perspective from discovery to targeting

Circular RNA circPHF16 enhances IL-17A expression and secretion by sequestering miR-378a-3p to activate the IL6ST axis in Graves' disease

Interleukin-17A (IL-17A) plays a pivotal role in the pathogenesis of Graves' disease (GD), an autoimmune disorder affecting thyroid function, but the detailed regulatory mechanisms remain elusive. Circular RNAs (circRNAs) have emerged as key regulators of IL-17A expression and secretion in autoimmune diseases, yet their specific role in GD, especially within CD4 + T lymphocytes, are not well understood. In this study, a circRNA, circPHF16 (hsa_circ_0090364) was found to be highly expressed in the peripheral blood mononuclear cells and serum of GD patients. In vitro experiments in Jurkat T cells revealed that silencing of circPHF16 suppressed IL-17A expression and secretion, while overexpression of circPHF16 had the opposite effect. Furthermore, bioinformatics analysis demonstrated a circPHF16/miR-378a-3p/IL6ST pathway, in which circPHF16 regulates IL6ST expression, which, in turn, influences IL-17A expression and secretion by interacting with miR-378a-3p. In vivo studies in a mouse model of GD showed similar trends in molecular expression levels, consistent with competitive endogenous RNA interactions. Together the results of the study identify circPHF16 as a potential target in the development of new strategies for GD diagnosis and treatment, and thus, offer a theoretical foundation for clinical therapeutic approaches in GD.

Functional single-cell analyses of mesenchymal stromal cell proliferation and differentiation using ALDH-activity and mitochondrial ROS content

BASKGROUND

Previous research has unveiled a stem cell-like transcriptome enrichment in the aldehyde dehydrogenase-expressing (ALDHhigh) mesenchymal stromal cell (MStroC) fraction. However, considering the heterogeneity of MStroCs, with only a fraction of them presenting bona fide stem cells (MSCs), the actual potency of ALDH as an MSC-specific selection marker remains an issue.

METHODS

To address this, the proliferative and differentiation potential of individual ALDHhigh and ALDHlow MStroCs incubated at low oxygen concentrations, estimated to mimic stem cell niches (0.1% O2), were assayed using single-cell clonal analysis, compared to standard conditions (20% O2).

RESULTS

We confirm that a high proliferative capacity and multi-potent MSCs are enriched in the ALDHhigh MStroC population, especially when cells are cultured at 0.1% O2. Measurements of reduced/oxidized glutathione and mitochondrial superoxide anions with MitoSoX (MSX) indicate that this advantage induced by low oxygen is related to a decrease in the oxidative and reactive oxygen species (ROS) levels in the stem cell metabolic setup. However, ALDH expression is neither specific nor exclusive to MSCs, as high proliferative capacity and multi-potent cells were also found in the ALDHlow fraction. Furthermore, single-cell assays performed after combined cell sorting based on ALDH and MSX showed that the MSXlow MStroC population is enriched in stem/progenitor cells in all conditions, irrespective of ALDH expression or culture oxygen concentration. Importantly, the ALDHhighMSXlow MStroC fraction exposed to 0.1% O2 was almost exclusively composed of genuine MSCs. In contrast, neither progenitors nor stem cells (with a complete absence of colony-forming ability) were detected in the MSXhigh fraction, which exclusively resides in the ALDHlow MStroC population.

CONCLUSION

Our study reveals that ALDH expression is not exclusively associated with MSCs. However, cell sorting using combined ALDH expression and ROS content can be utilized to exclude MStroCs lacking stem/progenitor cell properties.

Burkholderia cepacia in cystic fibrosis children and adolescents: overall survival and immune alterations

Background

In current literature there are only scarce data on the host inflammatory response during Burkholderia cepacia complex (Bcc) persistence. The primary objective of the present research was to carry out cross-sectional analyses of biomarkers and evaluate disease progression in cystic fibrosis (CF) patients with chronic Bcc infection and pathogen-free ones. The secondary aim was to assess prospectively overall survival of the study participants during up to 8 years of follow-up.

Methods

The study included 116 paediatric patients with CF; 47 CF patients were chronically infected with Bcc, and 69 individuals were Bcc free. Plasma and sputum biomarkers (neutrophil elastase, MMP-8, MMP-9, MMP-12, IL-2, IL-4, IL-6, IL-8, IL-10, IL-18, IL-22, IL-23, IL-17, IFN-γ, TGFβ1, TNF-α) were analysed using commercially available kits. Besides, inhibitory effect of dexamethasone on proliferative response of PHA-stimulated peripheral blood lymphocytes had been assessed.

Results

Bcc infected patients did not differ from Bcc free ones in demographic and clinical parameters, but demonstrated an increased rate of glucose metabolism disturbances and survival disadvantage during prolong follow-up period. Biomarkers analyses revealed elevated TNF-α and reduced IL-17F levels in sputum samples of Bcc infected patients. These patients also demonstrated improvement of peripheral blood lymphocyte sensitivity to steroid treatment and reduction in plasma pro-inflammatory (IL-17F and IL-18) and anti-inflammatory (TGFβ1 and IL-10) cytokine concentrations.

Conclusions

Reduction in IL-17F levels may have several important consequences including increase in steroid sensitivity and glycemic control disturbances. Further investigations are needed to clarify the role of IL-17 cytokines in CF complication development. Low plasma TGFβ1 and IL-10 levels in Bcc infected group may be a sign of subverted activity of regulatory T cells. Such immune alterations may be one of the factors contributing to the development of the cepacia syndrome.

The "root" causes behind the anti-inflammatory actions of ginger compounds in immune cells

Ginger (Zingiber officinale) is one of the most well-known spices and medicinal plants worldwide that has been used since ancient times to treat a plethora of diseases including cold, gastrointestinal complaints, nausea, and migraine. Beyond that, a growing body of literature demonstrates that ginger exhibits anti-inflammatory, antioxidant, anti-cancer and neuroprotective actions as well. The beneficial effects of ginger can be attributed to the biologically active compounds of its rhizome such as gingerols, shogaols, zingerone and paradols. Among these compounds, gingerols are the most abundant in fresh roots, and shogaols are the major phenolic compounds of dried ginger. Over the last two decades numerous in vitro and in vivo studies demonstrated that the major ginger phenolics are able to influence the function of various immune cells including macrophages, neutrophils, dendritic cells and T cells. Although the mechanism of action of these compounds is not fully elucidated yet, some studies provide a mechanistic insight into their anti-inflammatory effects by showing that ginger constituents are able to target multiple signaling pathways. In the first part of this review, we summarized the current literature about the immunomodulatory actions of the major ginger compounds, and in the second part, we focused on the possible molecular mechanisms that may underlie their anti-inflammatory effects.

A Perfect Storm: The Convergence of Aging, Human Immunodeficiency Virus Infection, and Inflammasome Dysregulation

The emergence of combination antiretroviral therapy (cART) has greatly transformed the life expectancy of people living with HIV (PWH). Today, over 76% of the individuals with HIV have access to this life-saving therapy. However, this progress has come with a new challenge: an increase in age-related non-AIDS conditions among patients with HIV. These conditions manifest earlier in PWH than in uninfected individuals, accelerating the aging process. Like PWH, the uninfected aging population experiences immunosenescence marked by an increased proinflammatory environment. This phenomenon is linked to chronic inflammation, driven in part by cellular structures called inflammasomes. Inflammatory signaling pathways activated by HIV-1 infection play a key role in inflammasome formation, suggesting a crucial link between HIV and a chronic inflammatory state. This review outlines the inflammatory processes triggered by HIV-1 infection and aging, with a focus on the inflammasomes. This review also explores current research regarding inflammasomes and potential strategies for targeting inflammasomes to mitigate inflammation. Further research on inflammasome signaling presents a unique opportunity to develop targeted interventions and innovative therapeutic modalities for combating HIV and aging-associated inflammatory processes.

Targeting fusion proteins of the interleukin family: A promising new strategy for the treatment of autoinflammatory diseases

As a means of communication between immune cells and non-immune cells, Interleukins (ILs) has the main functions of stimulating the proliferation and activation of inflammatory immune cells such as dendritic cells and lymphocytes, promote the development of blood cells and so on. However, dysregulation of ILs expression is a major feature of autoinflammatory diseases. The drugs targeting ILs or IL-like biologics have played an important role in the clinical treatment of autoinflammatory diseases. Nevertheless, the widespread use of IL products may result in significant off-target adverse reactions. Thus, there is a clear need to develop next-generation ILs products in the biomedical field. Fusion proteins are proteins created through the joining of two or more genes that originally coded for separate proteins. Over the last 30 years, there has been increasing interest in the use of fusion protein technology for developing anti-inflammatory drugs. In comparison to single-target drugs, fusion proteins, as multiple targets drugs, have the ability to enhance the cytokine therapeutic index, resulting in improved efficacy over classical drugs. The strategy of preparing ILs or their receptors as fusion proteins is increasingly used in the treatment of autoimmune and chronic inflammation. This review focuses on the efficacy of several fusion protein drugs developed with ILs or their receptors in the treatment of autoinflammatory diseases, in order to illustrate the prospects of this new technology as an anti-inflammatory drug development protocol in the future.

Orthodontically induced changes to the genetic profile in periodontal ligament tissue and cytokine release in gingival crevicular fluid - A pilot investigation

Background/purpose

It has been known that genetic factors influence orthodontic tooth movement, however, scientific research on humans is lacking. Therefore, this study aimed to investigate dynamic changes to the genetic profile in human periodontal ligament (PDL) tissue and cytokine release in gingival crevicular fluid (GCF) during the first 28 days of orthodontic treatment.

Materials and methods

Fifteen teeth from three patients were recruited. Full-mouth fixed appliances with extraction of four premolars and one maxillary third molar was planned for orthodontic treatment. GCF collection and tooth extraction were performed following force application for 0, 1, 3, 7, and 28 days. GCF was analyzed using multiplex immunoassay for 27 cytokines. PDL tissue was collected after extraction and submitted for RNA exome-sequencing using Illumina sequencing platform. Further analysis of differentially expressed genes (DEGs), gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and heatmaps were conducted.

Results

GCF cytokine levels varied among three patients; some patients exhibited a peak cytokine level on Day 0 whereas others did so on Days 1-3. In RNA exome sequencing data, GO and KEGG analyses showed that genes associated with sensory receptors were upregulated on Day 1, genes involved in bone remodeling were upregulated on Days 3 and 28, and genes related to osteoclast differentiation were upregulated on Day 7.

Conclusion

RNA sequencing data demonstrate that the specific types of genes are expressed at different time points, whereas the data on cytokine changes show a large variation in concentration levels and dynamic change patterns among the patients.

Elevated serum IL-6 levels predict treatment interruption in patients with moderate to severe psoriasis: a 6-year real-world cohort study

BACKGROUND

Real-world, primary data on the treatment of psoriasis are scarce, especially concerning the role of soluble biomarkers as outcome predictors.

OBJECTIVE

The authors evaluated the utility of Th1/Th17 serum cytokines along with clinical characteristics as predictors of drug survival in the treatment of psoriasis.

METHODS

The authors consecutively included participants with moderate to severe psoriasis who were followed up for 6 years. Baseline interferon-α, tumor necrosis factor-α, and interleukin (IL)-2, IL-4, IL-6, IL-10, and IL-17A were measured using a cytometric bead array; clinical data were assessed. The authors calculated hazard ratios (HRs) for drug survival using a Cox proportional hazards model.

RESULTS

The authors included 262 patients, most of whom used systemic immunosuppressants or biologics. In the multivariate model, poor quality of life measured by the Dermatology Life Quality Index (HR = 1.04; 95% CI 1.01‒1.07; p = 0.012) and elevated baseline IL-6 (HR = 1.99; 95% CI 1.29‒3.08; p = 0.002) were associated with treatment interruption.

STUDY LIMITATIONS

The main limitation of any cohort study is the presence of confounders that could not be detected in clinical evaluation.

CONCLUSIONS

Poor quality of life and elevated baseline serum IL-6 level predicted treatment interruption in patients with moderate to severe psoriasis. Although IL-6 is not the most important mediator of the inflammatory pathway in the skin environment, it is an interesting biomarker candidate for predicting psoriasis treatment response.

High-dimensional immune profiling using mass cytometry reveals IL-17A-producing γδ T cells as biomarkers in patients with T-cell-activated idiopathic severe aplastic anemia

Severe aplastic anemia (SAA) is a bone marrow failure syndrome characterized by activated T cells. Features of T-cell activation in the pathophysiology of SAA remain unknown. To understand T cell activation states, we investigated the atlas of peripheral immune cells and the secreted cytokine network with single cell mass cytometry analysis. We found decreased γδ T-cell frequencies in all patients with SAA, together with a significantly increased proportion of interleukin (IL)-17A-producing cell subsets. Cytokine network analysis of immune cells showed significant positive relationship between IL and 17A production from immune cells and disease severity of severe aplastic anemia. On separating SAA into two distinct subgroups based on T-cell activation stage, the proportion of γδ T cells tended to decrease in the T-cell-activated SAA group compared with non-T-cell-activated group. And the proportion of IL-17A-producing γδ T cells (γδT17) within γδ T cells was newly found to be significantly higher in the T-cell-activated SAA group, implying that IL-17A production by γδ T cells was associated with T-cell activation. Overall, our study revealed a role of γδT17 cells in mediating autoreactive T-cell activation in SAA and provided a novel diagnostic indicator for monitoring autoreactive T-cell activation status during the progression of aplastic anemia in the clinic.

Differential effects of interleukin-17A and 17F on cell interactions between immune cells and stromal cells from synovium or skin

We compared the contribution of IL-17A and IL-17F in co-culture systems mimicking cell interactions as found in inflamed synovium and skin. Synoviocytes or skin fibroblasts were co-cultured with activated PBMC, with IL-17A, IL-17 A/F, IL-17F, IL-23, anti-IL-17A, anti-IL-17A/F or anti-IL-17F antibodies. IL-17A, IL-17F, IL-6 and IL-10 production was measured at 48 h. mRNA expression of receptor subunits for IL-23, IL-12 and IL-17 was assessed at 24 h. Both cell activation and interactions were needed for a high IL-17A secretion while IL-17F was stimulated by PHA activation alone and further increased in co-cultures. IL-17F levels were higher than IL-17A in both co-cultures (p < 0.05). IL-17F addition decreased IL-17A secretion (p < 0.05) but IL-17A addition had no effect on IL-17F secretion. Interestingly, IL-17A and IL-17F upregulated IL-17RA and IL-17RC mRNA expression in PBMC/skin fibroblast co-cultures (p < 0.05) while only IL-17F exerted this effect in synoviocytes (p < 0.05). Monocyte exclusion in both co-cultures increased IL-17A and IL-17F (twofold, p < 0.05) while decreasing IL-10 and IL-6 secretion (twofold, p < 0.05). IL-17A and F had differential effects on their receptor expression with a higher sensitivity for skin fibroblasts highlighting the differential contribution of IL-17A and F in joint vs. skin diseases.

The IL-17 family in diseases: from bench to bedside

The interleukin-17 (IL-17) family comprises six members (IL-17A-17F), and recently, all of its related receptors have been discovered. IL-17 was first discovered approximately 30 years ago. Members of this family have various biological functions, including driving an inflammatory cascade during infections and autoimmune diseases, as well as boosting protective immunity against various pathogens. IL-17 is a highly versatile proinflammatory cytokine necessary for vital processes including host immune defenses, tissue repair, inflammatory disease pathogenesis, and cancer progression. However, how IL-17 performs these functions remains controversial. The multifunctional properties of IL-17 have attracted research interest, and emerging data have gradually improved our understanding of the IL-17 signaling pathway. However, a comprehensive review is required to understand its role in both host defense functions and pathogenesis in the body. This review can aid researchers in better understanding the mechanisms underlying IL-17's roles in vivo and provide a theoretical basis for future studies aiming to regulate IL-17 expression and function. This review discusses recent progress in understanding the IL-17 signaling pathway and its physiological roles. In addition, we present the mechanism underlying IL-17's role in various pathologies, particularly, in IL-17-induced systemic lupus erythematosus and IL-17-related tumor cell transformation and metastasis. In addition, we have briefly discussed promising developments in the diagnosis and treatment of autoimmune diseases and tumors.

Immunogenic Cell Death Associated Molecular Patterns and the Dual Role of IL17RA in Interstitial Cystitis/Bladder Pain Syndrome

The unclear etiology and pathogenesis of interstitial cystitis/bladder pain syndrome (IC/BPS) are responsible for the lack of effective treatment and the poor patient prognosis. Various studies show that chronic inflammation and immune responses are important factors contributing to the pathogenesis of IC/BPS. The process of immunogenic cell death (ICD) involves both the immune response and inflammatory process, and the involvement of ICD in IC/BPS pathogenesis has not been explored. Two IC/BPS transcriptome datasets collected from the Gene Expression Omnibus (GEO) database were used to identify distinct ICD-associated molecular patterns (IAMPs). IAMPs and IC/BPS subtypes were found to be related. The inflammatory immune microenvironments (IIME) in different IAMPs were studied. The potential mechanism by which the interleukin 17 receptor A (IL17RA) influences IC/BPS was examined using in vitro assays. The expression of ICD-related genes (IRGs) was upregulated in IC/BPS bladders, compared with normal bladders. Disease prediction models, based on differentially expressed IRGs, could accurately predict IC/BPS. The IC/BPS patients had two distinct IAMPs, each with its own subtype and clinical features and association with remodeling IIME. IL17RA, a well-established IC/BPS bladder biomarker, mediates both the inflammatory insult and the protective responses. In summary, the current study identified different IAMPs in IC/BPS, which may be involved in the pathogenesis of IC/BPS by remodeling the IIME. The chronic inflammatory process in IC/BPS may be prolonged by IL17RA, which could mediate both pro- and anti-inflammatory responses. The IL17RA-associated pathway may play a significant role in the development of IC/BPS and can be used as a therapeutic target.

Gallic acid regulates immune response in a mouse model of rheumatoid arthritis

INTRODUCTION

Previous studies revealed that gallic acid (GA) exerts anti-inflammation and immuno-regulatory properties. This study aims to explore the pharmacological activities of GA in collagen-induced arthritis (CIA) mouse model.

METHODS

Male DBA/1J mice were used to construct the CIA model. The mice were administrated with GA for 3 weeks. Clinical arthritis scores and hind paw volume were evaluated over the experimental period. qPCR and Western blot analysis were used to determine the levels of matrix metallopeptidases (MMPs) and cytokines. In addition, flow cytometry was used to measure the populations of Th17 and Treg cells. ELISAs were used to determine the cytokines in the serum and ankle joint tissues.

RESULTS

Treatment of GA (40 and 80 mg/kg/d) reduced clinical arthritis scores and hind paw volume in the CIA mouse model. Besides, treatment of GA reduced the overexpression of MMPs and modulated the dysregulation of inflammation-related cytokines. Flow cytometry showed that treatment of GA decreased the population of Th17 cells, and increased the population of Treg cells, as supported by treatment of GA regulated the Th17/Treg-related cytokines.

CONCLUSIONS

GA attenuates symptoms in the CIA mouse model by anti-inflammation and regulating Th17/Treg cell imbalance.

A novel GRK2 inhibitor alleviates experimental arthritis through restraining Th17 cell differentiation

T helper type 17 (Th17) cell which is induced by interleukine-6 (IL-6)-signal transducers and activators of transcription 3 (STAT3) signaling is a central pro-inflammatory T cell subtype in rheumatoid arthritis (RA) and could be significantly reduced by paeoniflorin-6'-O-benzene sulfonate (CP-25) treatment with unclear mechanisms. This study was aimed to found out the mechanism of CP-25 in hampering Th17 cells differentiation in arthritic animals thus explore more therapeutic targets for RA. In mice with collagen-induced arthritis (CIA), both circulating and splenic Th17 subsets were expanded with increased STAT3 phosphorylation and decreased Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP1)-β-arrestin2 (arrb2)-STAT3 interaction in CD4⁺ helper T (Th) cells. Either CP-25 or paroxetine (PAR), an established G protein coupled receptor kinase 2 (GRK2) inhibitor treatment effectively relieved the joints inflammation of CIA mice with substantially reduced Th17 cell population through inhibiting STAT3 and restoring the SHP1-arrb2-STAT3 complex. Knockout of arrb2 exacerbated the clinical manifestations of collagen antibody-induced arthritis with upregulated Th17 cells. In vitro studies revealed that depletion of arrb2 or inhibition of SHP1 promoted Th17 cell differentiation. Moreover, stimulation of adenosine A₃ receptor (A₃AR) simultaneously promoted Th17 cell differentiation via accelerating abbr2-A₃AR binding, which could be prevented through inhibiting GRK2 phosphorylation by CP-25 or PAR, or genetically reducing GRK2. This work has demonstrated that CP-25 or PAR treatment recovers the SHP1-arrb2-STAT3 complex which prevents STAT3 activation in Th cells through reducing arrb2 recruitment to A₃AR by inhibiting GRK2 phosphorylation, leading to the reduction in Th17 cell differentiation and arthritis attenuation.

Morphological and Mechanical Characterization of Extracellular Vesicles and Parent Human Synoviocytes under Physiological and Inflammatory Conditions

The morphology of fibroblast-like synoviocytes (FLS) issued from the synovial fluid (SF) of patients suffering from osteoarthritis (OA), rheumatoid arthritis (RA), or from healthy subjects (H), as well as the ultrastructure and mechanical properties of the FLS-secreted extracellular vesicles (EV), were analyzed by confocal microscopy, transmission electron microscopy, atomic force microscopy, and tribological tests. EV released under healthy conditions were constituted of several lipid bilayers surrounding a viscous inner core. This "gel-in" vesicular structure ensured high mechanical resistance of single vesicles and good tribological properties of the lubricant. RA, and to a lesser extent OA, synovial vesicles had altered morphology, corresponding to a "gel-out" situation with vesicles surrounded by a viscous gel, poor mechanical resistance, and poor lubricating qualities. When subjected to inflammatory conditions, healthy cells developed phenotypes similar to that of RA samples, which reinforces the importance of inflammatory processes in the loss of lubricating properties of SF.

Metabolic requirements of Th17 cells and of B cells: Regulation and defects in health and in inflammatory diseases

The immune system protects from infections and cancer through complex cellular networks. For this purpose, immune cells require well-developed mechanisms of energy generation. However, the immune system itself can also cause diseases when defective regulation results in the emergence of autoreactive lymphocytes. Recent studies provide insights into how differential patterns of immune cell responses are associated with selective metabolic pathways. This review will examine the changing metabolic requirements of Th17 cells and of B cells at different stages of their development and activation. Both cells provide protection but can also mediate diseases through the production of autoantibodies and the production of proinflammatory mediators. In health, B cells produce antibodies and cytokines and present antigens to T cells to mount specific immunity. Th17 cells, on the other hand, provide protection against extra cellular pathogens at mucosal surfaces but can also drive chronic inflammation. The latter cells can also promote the differentiation of B cells to plasma cells to produce more autoantibodies. Metabolism-regulated checkpoints at different stages of their development ensure the that self-reactive B cells clones and needless production of interleukin (IL-)17 are limited. The metabolic regulation of the two cell types has some similarities, e.g. the utility of hypoxia induced factor (HIF)1α during low oxygen tension, to prevent autoimmunity and regulate inflammation. There are also clear differences, as Th17 cells only are vulnerable to the lack of certain amino acids. B cells, unlike Th17 cells, are also dependent of mechanistic target of rapamycin 2 (mTORC2) to function. Significant knowledge has recently been gained, particularly on Th17 cells, on how metabolism regulates these cells through influencing their epigenome. Metabolic dysregulation of Th17 cells and B cells can lead to chronic inflammation. Disease associated alterations in the genome can, in addition, cause dysregulation to metabolism and, thereby, result in epigenetic alterations in these cells. Recent studies highlight how pathology can result from the cooperation between the two cell types but only few have so far addressed the key metabolic alterations in such settings. Knowledge of the impact of metabolic dysfunction on chronic inflammation and pathology can reveal novel therapeutic targets to treat such diseases.

Intranasal administration of abatacept enhances IL-35+ and IL-10+ producing Bregs in lung tissues of ovalbumin-sensitized asthmatic mice model

Backgrounds

Treating asthmatic rheumatoid arthritis patients with abatacept has been shown to associate with better control of asthma symptoms. However, the mechanism behind that is not investigated.

Methods

Ovalbumin (OVA)- sensitized BALB/c female mice were treated intranasally (IN) or intraperitoneally (IP) with abatacept 4 hrs before the OVA challenge. The effects of abatacept IN or IP on the lungs and blood levels of Tregs and Bregs and their production of immunosuppressive cytokines, were determined using FACS analysis and ELISA assay.

Results

Treating OVA- sensitized asthmatic mice model with abatacept, IN or IP, reduced lung inflammation. IN treatment with abatacept increased the frequency of IL-35 and IL-10 producing Bregs in the lung tissues to a higher level compared to IP treatment. Moreover, the frequency of lungs LAG3⁺ Tregs was significantly increased following treatment. This was also associated with a reduction in lung tissue and serum IL-17 levels of treated mice.

Conclusions

These results suggest that abatacept by enhancing IL-35⁺IL-10⁺ Bregs and LAG3⁺ Tregs might reverse IL-17 induced lung inflammation during asthma.

Inhibition of IL-17A Protects against Thyroid Immune-Related Adverse Events while Preserving Checkpoint Inhibitor Antitumor Efficacy

Immune checkpoint inhibitor (ICI) immunotherapy leverages the body's own immune system to attack cancer cells but leads to unwanted autoimmune side effects in up to 60% of patients. Such immune-related adverse events (IrAEs) may lead to treatment interruption, permanent organ dysfunction, hospitalization, and premature death. Thyroiditis is one of the most common IrAEs, but the cause of thyroid IrAEs remains unknown. In this study, we use a new, physiologically relevant mouse model of ICI-associated autoimmunity to identify a key role for type 3 immune cells in the development of thyroid IrAEs. Multiple lineages of IL-17A-producing T cells expand in thyroid tissue with ICI treatment. Intrathyroidal IL-17A-producing innate-like γδT17 cells were increased in tumor-free mice, whereas adaptive Th17 cells were also prominent in tumor-bearing mice, following ICI treatment. Furthermore, Ab-based inhibition of IL-17A, a clinically available therapy, significantly reduced thyroid IrAE development in ICI-treated mice with and without tumor challenge. Finally, combination of IL-17A neutralization with ICI treatment in multiple tumor models did not reduce ICI antitumor efficacy. These studies suggest that targeting Th17 and γδT17 cell function via the IL-17A axis may reduce IrAEs without impairing ICI antitumor efficacy and may be a generalizable strategy to address type 3 immune-mediated IrAEs.

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.

Saliva and Serum Cytokine Profiles During Oral Ulceration in Behçet's Disease

Behçet's disease (BD) is a chronic, multi-systemic disorder of unknown aetiology typified by recurrent oral and genital mucocutaneous lesions, uveitis and vasculitis. Innate and adaptive immune system dysregulation has been implicated in pathogenesis with alterations in serum cytokine profiles. Few studies have investigated salivary cytokines in BD, despite more than 90% of BD patients first presenting with oral ulceration. The aim of this pilot study was twofold; firstly to investigate whether cytokine levels in matched serum and saliva samples show a differential profile in BD (with and without oral ulcers), recurrent aphthous stomatitis (RAS) and healthy controls (HCs), and secondly, to explore if any differential profiles in serum and/or saliva could provide a panel of cytokines with diagnostic and therapeutic potential for BD. Concentrations of 12 cytokines (IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-17A, IFN-γ, TNF-α, TNF-β) were measured using the Human Th1/Th2 11-Plex FlowCytomix™ kit with IL-17A, in BD (N=20), RAS (N=6) and HCs (N=10). A differential range of cytokines was detected in serum and saliva with the majority of cytokine levels higher in saliva. The most prevalent salivary cytokines were IL-1β, IL-2, IL-8, IL-10 and TNF-α present in all samples in contrast to serum where the most prevalent cytokine detected was IL-8 (91.9%). The least abundant cytokine was IFN-γ in both saliva (43.2%) and serum (2.7%). After normalizing saliva for protein content, BD patients with oral ulcers (BD-MA) had significantly higher levels of salivary IL-1β (p=0.01), IL-8 (p=0.02), TNF-α (p=0.004) and IL-6 (p=0.01) than HCs. Notably, BD patients without oral ulcers (BD-MQ) also had significantly higher salivary IL-1β, IL-8 and TNF-α (p ≤ 0.05) than HCs. During relapsed (BD-RE) and quiet (BD-Q) systemic episodes, salivary IL-β and TNF-α were also significantly increased with IL-8 significantly higher only in BD-Q (p=0.02). BD oral ulcers signify a potential reactivation of systemic inflammation. Identifying cytokines released during asymptomatic episodes and oral ulceration might lead to targeted drug therapy to prevent recurrent oral ulcers and possible disease relapse. This is the first study to report salivary cytokine levels in BD. The detectable levels suggests cytokine profiling of BD saliva may provide an alternative, less invasive, sensitive procedure for frequent monitoring of disease activity and progression.

Targeting MyD88 Downregulates Inflammatory Mediators and Pathogenic Processes in PBMC From DMARDs-Naïve Rheumatoid Arthritis Patients

MyD88-dependent intracellular signalling cascades and subsequently NF-kappaB-mediated transcription lead to the dynamic inflammatory processes underlying the pathogenesis of rheumatoid arthritis (RA) and related autoimmune diseases. This study aimed to identify the effect of the MyD88 dimerization inhibitor, ST2825, as a modulator of pathogenic gene expression signatures and systemic inflammation in disease-modifying antirheumatic drugs (DMARDs)-naïve RA patients. We analyzed bulk RNA-seq from peripheral blood mononuclear cells (PBMC) in DMARDs-naïve RA patients after stimulation with LPS and IL-1β. The transcriptional profiles of ST2825-treated PBMC were analyzed to identify its therapeutic potential. Ingenuity Pathway Analysis was implemented to identify downregulated pathogenic processes. Our analysis revealed 631 differentially expressed genes between DMARDs-naïve RA patients before and after ST2825 treatment. ST2825-treated RA PBMC exhibited a gene expression signature similar to that of healthy controls PBMC by downregulating the expression of proinflammatory cytokines, chemokines and matrix metalloproteases. In addition, B cell receptor, IL-17 and IL-15 signalling were critically downregulated pathways by ST2825. Furthermore, we identified eight genes (MMP9, CXCL9, MZB1, FUT7, TGM2, IGLV1-51, LINC01010, and CDK1) involved in pathogenic processes that ST2825 can potentially inhibit in distinct cell types within the RA synovium. Overall, our findings indicate that targeting MyD88 effectively downregulates systemic inflammatory mediators and modulates the pathogenic processes in PBMC from DMARDs-naïve RA patients. ST2825 could also potentially inhibit upregulated genes in the RA synovium, preventing synovitis and joint degeneration.

Regulation of the mesenchymal stem cell fate by interleukin-17: Implications in osteogenic differentiation

Bone regeneration is a tightly regulated process that ensures proper repair and functionality after injury. The delicate balance between bone formation and resorption is governed by cytokines and signaling molecules released during the inflammatory response. Interleukin (IL)-17A, produced in the early phase of inflammation, influences the fate of osteoprogenitors. Due to their inherent capacity to differentiate into osteoblasts, mesenchymal stem/stromal cells (MSCs) contribute to bone healing and regeneration. This review presents an overview of IL-17A signaling and the leading cellular and molecular mechanisms by which it regulates the osteogenic differentiation of MSCs. The main findings demonstrating IL-17A’s influence on osteoblastogenesis are described. To this end, divergent information exists about the capacity of IL-17A to regulate MSCs’ osteogenic fate, depending on the tissue context and target cell type, along with contradictory findings in the same cell types. Therefore, we summarize the data showing both the pro-osteogenic and anti-osteogenic roles of IL-17, which may help in the understanding of IL-17A function in bone repair and regeneration.

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.

Managing Psoriatic Arthritis With Inflammatory Bowel Disease and/or Uveitis

Psoriatic arthritis (PsA) is a chronic inflammatory disease that presents with psoriasis (PsO), peripheral and axial arthropathy. The heterogeneity of disease presentation leads to the term "psoriatic disease (PsD)" which is thought to better encompass the range of clinical manifestations. PsA is associated with several comorbidities such as cardiovascular diseases, metabolic syndrome and other extra-articular manifestations including uveitis, and inflammatory bowel disease (IBD). While novel therapeutics are being developed following advances in our understanding of the pathogenesis of the disease, the diverse combinations of PsA with its various comorbidities still pose a clinical challenge in managing patients with PsA. This article reviews our current understanding of the pathogenesis of PsA and how various pathways in the pathogenesis lead to the two comorbid extra-articular manifestations - uveitis and IBD. We also review current evidence of treatment strategies in managing patients with PsA with comorbidities of uveitis and/or IBD.

clusterProfiler 4.0: A universal enrichment tool for interpreting omics data

Functional enrichment analysis is pivotal for interpreting high-throughput omics data in life science. It is crucial for this type of tool to use the latest annotation databases for as many organisms as possible. To meet these requirements, we present here an updated version of our popular Bioconductor package, clusterProfiler 4.0. This package has been enhanced considerably compared with its original version published 9 years ago. The new version provides a universal interface for functional enrichment analysis in thousands of organisms based on internally supported ontologies and pathways as well as annotation data provided by users or derived from online databases. It also extends the dplyr and ggplot2 packages to offer tidy interfaces for data operation and visualization. Other new features include gene set enrichment analysis and comparison of enrichment results from multiple gene lists. We anticipate that clusterProfiler 4.0 will be applied to a wide range of scenarios across diverse organisms.

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clusterProfiler supports exploring functional characteristics of both coding and non-coding genomics data for thousands of species with up-to-date gene annotation

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It provides a universal interface for gene functional annotation from a variety of sources and thus can be applied in diverse scenarios

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It provides a tidy interface to access, manipulate, and visualize enrichment results to help users achieve efficient data interpretation

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Datasets obtained from multiple treatments and time points can be analyzed and compared in a single run, easily revealing functional consensus and differences among distinct conditions

Interleukin-17A in Alzheimer's disease: recent advances and controversies

Alzheimer’s disease (AD) is a progressive neurodegenerative disease that mainly affects older adults. Although the global burden of AD is increasing year by year, the causes of AD remain largely unknown. Numerous basic and clinical studies have shown that interleukin-17A (IL-17A) may play a significant role in the pathogenesis of AD. A comprehensive assessment of the role of IL-17A in AD would benefit the diagnosis, understanding of etiology and treatment. However, over the past decade, controversies remain regarding the expression level and role of IL-17A in AD. We have incorporated newly published researches and point out that IL-17A expression levels may vary along with the development of AD, exercising different roles at different stages of AD, although much more work remains to be done to support the potential role of IL-17A in AD-related pathology. Here, it is our intention to review the underlying mechanisms of IL-17A in AD and address the current controversies in an effort to clarify the results of existing research and suggest future studies.

Reactivation of latent tuberculosis with TNF inhibitors: critical role of the beta 2 chain of the IL-12 receptor

Tumor necrosis factor (TNF) inhibitors have improved a lot the treatment of numerous diseases, with the well-known example of rheumatoid arthritis (RA). In the early 2000s, postmarketing data quickly revealed an alarming number of severe tuberculosis (TB) under such treatment. These findings were consistent with previous results in mice where TNF is essential for lymph node formation and granuloma organization. The effects of TNF inhibition on RA synovium structure are very similar to those on granuloma, with changes in cellular interactions, cytokine, and chemokine production. In addition to the role of TNF in granuloma, the interleukin (IL)-12/interferon (IFN)-γ pathway is required for an efficient host defense against TB. Primary and secondary immunodeficiencies affecting this pathway lead to severe bacillus Calmette-Guérin (BCG) reaction or full TB. Any chronic inflammation as in RA induces a systemic Th1 defect that predisposes to TB through specific downregulation of the IL-12Rß2 chain. When TNF inhibitors are initiated, this transiently increases this risk of TB, through effects on cellular interactions in a latent TB granuloma. At a later stage, when a better control disease activity is obtained, the risk of TB is reduced but not abrogated. Given the clear benefit from TNF inhibition, latent TB infection screening at baseline is essential for an optimal safety.

Anti-arthritic activity of Ricinus communis L. and Withania somnifera L. extracts in adjuvant-induced arthritic rats via modulating inflammatory mediators and subsiding oxidative stress

OBJECTIVES

This study aimed to evaluate the anti-arthritic activity of Ricinus communis leaves' and Withania somnifera roots' hydroalcoholic extracts in Complete Freund's adjuvant-induced arthritis in Wistar rats.

MATERIALS AND METHODS

HPLC and FT-IR analysis detected pharmacologically important phytocompounds in both plant extracts. Oral treatments including methotrexate (MTX; 3 mg/kg twice a week) and extracts at 250 and 500 mg/kg/day were initiated after arthritis induction. Changes in paw swelling, arthritic score, body weight, organ indices (thymus and spleen), hematological and biochemical parameters, and pro-/anti-inflammatory cytokine expression using qRT-PCR were assessed. Oxidative stress markers in hepatic tissue were determined. Histopathological and radiological examinations were also performed.

RESULTS

RCE (R. communis extract) and WSE (W. somnifera extract) demonstrated a reduction in paw swelling, arthritic score, and restoration of body weight and organ indices. Hematological parameters, serum inflammatory markers such as CRP and RF, and liver function markers of arthritic rats were significantly (P<0.01) ameliorated with RCE and WSE treatment. Both plants persuasively down-regulated IL-1β, IL-6, IL-17a, TNF-α, and RANKL and up-regulated IL-4, INF-γ, and OPG relative expression as well as alleviating hepatic oxidative stress parameters. Histopathological and radiological findings revealed a marked reduction in tissue inflammation and bone erosion in extracts treated groups.

CONCLUSION

The study findings suggest that R. communis leaves and W. somnifera roots have markedly subsided inflammation and improved health through modulating pro-/anti-inflammatory cytokine expression and reducing oxidative stress.