Disturbed regulatory T cell homeostasis in multiple sclerosis

JAK2/STAT3 Pathway Inhibition by AG490 Ameliorates Experimental Autoimmune Encephalomyelitis via Regulation of Th17 Cells and Autophagy

Multiple sclerosis (MS) is an autoimmune inflammatory condition affecting the central nervous system, and experimental autoimmune encephalomyelitis (EAE) animal models have been extensively used to study it. T-helper 17 cells, which produce interleukin-17(IL-17), play crucial roles in MS pathogenesis, and the JAK2/STAT3 pathway has an essential function in their differentiation from naive CD4 + T cells. This study investigated the effects of the JAK2/STAT3 pathway inhibitor AG490 on EAE in vivo and in vitro, as well as the underlying mechanisms. AG490 ameliorated EAE severity and attenuated its typical symptoms by downregulating proteins associated with the JAK2/STAT3 pathway. Furthermore, it decreased T-helper 17 cell differentiation from naive CD4 + T cells by inactivating STAT3. In addition, it conferred protective effects against EAE by restoring autophagy. These findings indicate the potential of AG490 as a candidate anti-MS therapeutic.

LncRNAs involvement in pathogenesis of immune-related disease via regulation of T regulatory cells, an updated review

The pathophysiology of several illnesses, including cancer and autoimmune diseasesdepends on human regulatory T cells (Tregs), and abnormalities in these cells may function as triggers for these conditions. Cancer and autoimmune, and gynecological diseases are associated with the differentiation of the proinflammatory T cell subset TH17 and its balance with the production of Treg. Recently, long non-coding RNAs (lncRNAs) have become important regulatory molecules in a wide range of illnesses. During epigenetic regulation, they can control the expression of important genes at several levels by affecting transcription, post-transcriptional actions, translation, and protein modification. They might connect with different molecules, such as proteins, DNA and RNA, and their structural composition is intricate. Because lncRNAs regulatebiological processes, including cell division, death, and growth, they are linked to severaldiseases. A notable instance of this is the lncRNA NEAT1, which has been the subject of several investigations to ascertain its function in immune cell development. In the context of immune cell development, several additional lncRNAs have been connected to Treg cell differentiation. In this work, we summarize current findings about the diverse functions of lncRNAs in Treg cell differentiation and control of the Th17/Treg homeostasis in autoimmune disorders, cancers, as well as several gynecological diseases where Tregs are key players.

Amelioration of experimental autoimmune encephalomyelitis by gemfibrozil in mice via PPARβ/δ: implications for multiple sclerosis

It is important to describe effective and non-toxic therapies for multiple sclerosis (MS), an autoimmune demyelinating disease. Experimental autoimmune encephalomyelitis (EAE) is an immune-mediated inflammatory disease that serves as a model for MS. Earlier we and others have shown that, gemfibrozil, a lipid-lowering drug, exhibits therapeutic efficacy in EAE. However, the underlying mechanism was poorly understood. Although gemfibrozil is a known ligand of peroxisome proliferator-activated receptor α (PPARα), here, we established that oral administration of gemfibrozil preserved the integrity of blood-brain barrier (BBB) and blood-spinal cord barrier (BSB), decreased the infiltration of mononuclear cells into the CNS and inhibited the disease process of EAE in both wild type and PPARα-/- mice. On the other hand, oral gemfibrozil was found ineffective in maintaining the integrity of BBB/BSB, suppressing inflammatory infiltration and reducing the disease process of EAE in mice lacking PPARβ (formerly PPARδ), indicating an important role of PPARβ/δ, but not PPARα, in gemfibrozil-mediated preservation of BBB/BSB and protection of EAE. Regulatory T cells (Tregs) play a critical role in the disease process of EAE/MS and we also demonstrated that oral gemfibrozil protected Tregs in WT and PPARα-/- EAE mice, but not PPARβ-/- EAE mice. Taken together, our findings suggest that gemfibrozil, a known ligand of PPARα, preserves the integrity of BBB/BSB, enriches Tregs, and inhibits the disease process of EAE via PPARβ, but not PPARα.

Engineered Treg cells: The heir to the throne of immunotherapy

Recently, increased interest in the use of Tregs as adoptive cell therapy for the treatment of autoimmune diseases and transplant rejection had led to several advances in the field. However, Treg cell therapies, while constantly advancing, indiscriminately suppress the immune system without the permanent stabilization of certain diseases. Genetically modified Tregs hold great promise towards solving these problems, but, challenges in identifying the most potent Treg subtype, accompanied by the ambiguity involved in identifying the optimal Treg source, along with its expansion and engineering in a clinical-grade setting remain paramount. This review highlights the recent advances in methodologies for the development of genetically engineered Treg cell-based treatments for autoimmune, inflammatory diseases, and organ rejection. Additionally, it provides a systematized guide to all the recent progress in the field and informs the readers of the feasibility and safety of engineered adoptive Treg cell therapy, with the aim to provide a framework for researchers involved in the development of engineered Tregs.

Altered T cell development in an animal model of multiple sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disease that affects the central nervous system (CNS), leading to demyelination and axonal degeneration. Experimental autoimmune encephalomyelitis (EAE) is an animal model of MS that has significantly improved our understanding of MS. Studies have observed early thymic involution in MS patients, suggesting the potential involvement of the thymus in CNS autoimmunity. However, our knowledge of the thymus's role in autoimmune disorders affecting the CNS remains limited. In this study, we examined the effects of EAE induction on thymopoiesis and observed alterations in T cell development. These changes were characterized by increased apoptosis and decreased proliferation of thymocytes at the EAE peak stage. We also identified a blockade in the transition from CD4-CD8- double-negative thymocytes to CD4+CD8+ double-positive cells, as evidenced by the accumulation of double-negative stage 1 thymocytes at both the EAE onset and peak stages. Furthermore, positive selection was disrupted in the thymus of EAE mice at both stages, leading to an elevated proportion and number of CD4+CD8- and CD4-CD8+ single-positive cells. Meanwhile, we observed an augmented production of regulatory T cells in the thymus of EAE mice. Moreover, peripheral blood analysis of EAE mice at the onset stage showed expanded T cell subsets but not at the peak stage. We also observed altered expression patterns in thymus-derived CD4+CD8- and CD4-CD8+ single-positive cells between MS patients and healthy controls. Our findings demonstrate a modified T cell development in EAE/MS, providing valuable insights into the potential of modulating thymic function as a targeted therapeutic approach to MS/EAE.

Game of microbes: the battle within - gut microbiota and multiple sclerosis

Multiple sclerosis (MS) is a chronic and progressive autoimmune disease of the central nervous system (CNS), with both genetic and environmental factors contributing to the pathobiology of the disease. While human leukocyte antigen (HLA) genes have emerged as the strongest genetic factor, consensus on environmental risk factors are lacking. Recently, trillions of microbes residing in our gut (microbiome) have emerged as a potential environmental factor linked with the pathobiology of MS as PwMS show gut microbial dysbiosis (altered gut microbiome). Thus, there has been a strong emphasis on understanding the factors (host and environmental) regulating the composition of the gut microbiota and the mechanism(s) through which gut microbes contribute to MS disease, especially through immune system modulation. A better understanding of these interactions will help harness the enormous potential of the gut microbiota as a therapeutic approach to treating MS.

Histamine H4 Receptor Antagonist Ameliorates the Progression of Experimental Autoimmune Encephalomyelitis via Regulation of T-Cell Imbalance

Multiple sclerosis (MS) is a degenerative condition characterized by immune-mediated attacks on the central nervous system (CNS), resulting in demyelination and recurring T-cell responses. The histamine H4 receptor (H4R) is mainly expressed in cellular populations and plays a vital role in inflammation and immunological responses. The role of H4R in neurons of the CNS has recently been revealed. However, the precise role of H4R in neuronal function remains inadequately understood. The objective of this work was to investigate the impact of JNJ 10191584 (JNJ), a highly effective and specific H4R antagonist, on the development of experimental autoimmune encephalomyelitis (EAE) and to gain insight into the underlying mechanism involved. In this study, we examined the potential impact of JNJ therapy on the course of EAE in SJL/J mice. EAE mice were administered an oral dose of JNJ at a concentration of 6 mg/kg once a day, starting from day 10 and continuing until day 42. Afterward, the mice's clinical scores were assessed. In this study, we conducted additional research to examine the impact of JNJ on several types of immune cells, specifically Th1 (IFN-γ and T-bet), Th9 (IL-9 and IRF4), Th17 (IL-17A and RORγt), and regulatory T (Tregs; Foxp3 and TGF-β1) cells in the spleen. In this study, we further investigated the impact of JNJ on the mRNA expression levels of IFN-γ, T-bet, IL-9, IRF4, IL-17A, RORγt, Foxp3, and TGF-β1 in the brain. Daily treatment of JNJ effectively reduced the development of EAE in mice. The percentages of CD4+IFN-γ+, CD4+T-bet+, CD4+IL-9+, CD4+IRF4+, CD4+IL-17A+, and CD4+RORγt+ cells were shown to decrease, whereas the percentages of CD4+TGF-β1+ and CD4+Foxp3+ cells were observed to increase in EAE mice treated with JNJ. Therefore, the HR4 antagonist positively affected the course of EAE by modulating the signaling of transcription factors. The identified results include possible ramifications in the context of MS treatment.

Pathological role of LncRNAs in immune-related disease via regulation of T regulatory cells

Human regulatory T cells (Tregs) are essential in pathogenesis of several diseases such as autoimmune diseases and cancers, and their imbalances may be promoting factor in these disorders. The development of the proinflammatory T cell subset TH17 and its balance with the generation of regulatory T cells (Treg) is linked to autoimmune disease and cancers. Long non-coding RNAs (lncRNAs) have recently emerged as powerful regulatory molecules in a variety of diseases and can regulate the expression of significant genes at multiple levels through epigenetic regulation and by modulating transcription, post-transcriptional processes, translation, and protein modification. They may interact with a wide range of molecules, including DNA, RNA, and proteins, and have a complex structural makeup. LncRNAs are implicated in a range of illnesses due to their regulatory impact on a variety of biological processes such as cell proliferation, apoptosis, and differentiation. In this regard, a prominent example is lncRNA NEAT1 which several studies have performed to determine its role in the differentiation of immune cells. Many other lncRNAs have been linked to Treg cell differentiation in the context of immune cell differentiation. In this study, we review recent research on the various roles of lncRNAs in differentiation of Treg cell and regulation of the Th17/Treg balance in autoimmune diseases and tumors in which T regs play an important role.

Interferon-gamma ameliorates experimental autoimmune encephalomyelitis by inducing homeostatic adaptation of microglia

Compelling evidence has shown that interferon (IFN)-γ has dual effects in multiple sclerosis and in its animal model of experimental autoimmune encephalomyelitis (EAE), with results supporting both a pathogenic and beneficial function. However, the mechanisms whereby IFN-γ may promote neuroprotection in EAE and its effects on central nervous system (CNS)-resident cells have remained an enigma for more than 30 years. In this study, the impact of IFN-γ at the peak of EAE, its effects on CNS infiltrating myeloid cells (MC) and microglia (MG), and the underlying cellular and molecular mechanisms were investigated. IFN-γ administration resulted in disease amelioration and attenuation of neuroinflammation associated with significantly lower frequencies of CNS CD11b⁺ myeloid cells and less infiltration of inflammatory cells and demyelination. A significant reduction in activated MG and enhanced resting MG was determined by flow cytometry and immunohistrochemistry. Primary MC/MG cultures obtained from the spinal cord of IFN-γ-treated EAE mice that were ex vivo re-stimulated with a low dose (1 ng/ml) of IFN-γ and neuroantigen, promoted a significantly higher induction of CD4⁺ regulatory T (Treg) cells associated with increased transforming growth factor (TGF)-β secretion. Additionally, IFN-γ-treated primary MC/MG cultures produced significantly lower nitrite in response to LPS challenge than control MC/MG. IFN-γ-treated EAE mice had a significantly higher frequency of CX3CR1^high MC/MG and expressed lower levels of program death ligand 1 (PD-L1) than PBS-treated mice. Most CX3CR1^highPD-L1^lowCD11b⁺Ly6G^- cells expressed MG markers (Tmem119, Sall2, and P2ry12), indicating that they represented an enriched MG subset (CX3CR1^highPD-L1^low MG). Amelioration of clinical symptoms and induction of CX3CR1^highPD-L1^low MG by IFN-γ were dependent on STAT-1. RNA-seq analyses revealed that in vivo treatment with IFN-γ promoted the induction of homeostatic CX3CR1^highPD-L1^low MG, upregulating the expression of genes associated with tolerogenic and anti-inflammatory roles and down-regulating pro-inflammatory genes. These analyses highlight the master role that IFN-γ plays in regulating microglial activity and provide new insights into the cellular and molecular mechanisms involved in the therapeutic activity of IFN-γ in EAE.

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

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

Modulation of Tregs and iNKT by Fingolimod in Multiple Sclerosis Patients

The altered numbers and functions of cells belonging to immunoregulatory cell networks such as T regulatory (Tregs) and invariant Natural Killer T (iNKT) cells have been reported in Multiple Sclerosis (MS), an immune-mediated disease. We aimed to assess the frequencies of Tregs and iNKT cells in MS patients throughout a one-year treatment with fingolimod (FTY) and to correlate immunological data with efficacy and safety data. The percentage of Tregs (defined as Live Dead-CD3 + CD4 + FoxP3 + CD25++/CD127- cells) increased steadily throughout the year, while there was no significant difference in the absolute number or percentage of iNKT cells (defined as CD3 + CD14-CD19- Vα24-Jα18 TCR+ cells). However, out of all the iNKT cells, the CD8+ iNKT and CD4-CD8- double-negative (DN) cell percentages steadily increased, while the CD4+ iNKT cell percentages decreased significantly. The mean percentage of CD8+ T cells at all time-points was lower in patients with infections throughout the study. The numbers and percentages of DN iNKT cells were more elevated, considering all time-points, in patients who presented a clinical relapse. FTY may, therefore, exert its beneficial effect in MS patients through various mechanisms, including the increase in Tregs and in iNKT subsets with immunomodulatory potential such as CD8+ iNKT cells. The occurrence of infections was associated with lower mean CD8+ cell counts during treatment with FTY.

Cumulative Roles for Epstein-Barr Virus, Human Endogenous Retroviruses, and Human Herpes Virus-6 in Driving an Inflammatory Cascade Underlying MS Pathogenesis

Roles for viral infections and aberrant immune responses in driving localized neuroinflammation and neurodegeneration in multiple sclerosis (MS) are the focus of intense research. Epstein-Barr virus (EBV), as a persistent and frequently reactivating virus with major immunogenic influences and a near 100% epidemiological association with MS, is considered to play a leading role in MS pathogenesis, triggering localized inflammation near or within the central nervous system (CNS). This triggering may occur directly via viral products (RNA and protein) and/or indirectly via antigenic mimicry involving B-cells, T-cells and cytokine-activated astrocytes and microglia cells damaging the myelin sheath of neurons. The genetic MS-risk factor HLA-DR2b (DRB1*1501β, DRA1*0101α) may contribute to aberrant EBV antigen-presentation and anti-EBV reactivity but also to mimicry-induced autoimmune responses characteristic of MS. A central role is proposed for inflammatory EBER1, EBV-miRNA and LMP1 containing exosomes secreted by viable reactivating EBV+ B-cells and repetitive release of EBNA1-DNA complexes from apoptotic EBV+ B-cells, forming reactive immune complexes with EBNA1-IgG and complement. This may be accompanied by cytokine- or EBV-induced expression of human endogenous retrovirus-W/-K (HERV-W/-K) elements and possibly by activation of human herpesvirus-6A (HHV-6A) in early-stage CNS lesions, each contributing to an inflammatory cascade causing the relapsing-remitting neuro-inflammatory and/or progressive features characteristic of MS. Elimination of EBV-carrying B-cells by antibody- and EBV-specific T-cell therapy may hold the promise of reducing EBV activity in the CNS, thereby limiting CNS inflammation, MS symptoms and possibly reversing disease. Other approaches targeting HHV-6 and HERV-W and limiting inflammatory kinase-signaling to treat MS are also being tested with promising results. This article presents an overview of the evidence that EBV, HHV-6, and HERV-W may have a pathogenic role in initiating and promoting MS and possible approaches to mitigate development of the disease.

Study on the preparation and function of regulatory T cells from human peripheral blood

Background

Regulatory T cells (Tregs) are an important cell subgroup of CD4⁺ T cells. Treg cells are critically involved in inducing immune tolerance, maintaining immune environment homeostasis, and preventing the occurrence of autoimmune diseases. Under normal conditions, the number of Tregs in the body is very small. This research was designed to establish an effective method to expand human peripheral blood Tregs in vitro and to analyze phenotype, purity, and function of Treg cells post-expansion.

Methods

Peripheral blood was obtained from healthy donors. CD4⁺CD25⁺CD127^dim/− Treg cells were isolated from peripheral blood mononuclear cells (PBMCs) by magnetic-activated cell sorting (MACS), and an optimized culture system was used for amplification. The in vitro amplification ability of Treg cells was evaluated to determine the expression and purity of Treg cell-specific surface markers in different culture cycles. The suppressive function of Treg was determined by in vitro lymphocyte proliferation assay.

Results

Treg cells could be successfully isolated by magnetic activated cell sorting (MACS). After 21 days of in vitro culture, the mean expansion fold was 2,009±452.2 in ≤60 years, and there was a significant difference between the younger group and the older than 60 years group (1,238±330.0). Flow cytometry analysis revealed that the percentages of CD4⁺CD25⁺ cells and FOXP3⁺ cells were (93.25±3.05)% and (94.19±4.21)% on day 14, and (92.86±4.36)% and (91.55±5.62)% on day 21, respectively. In addition, the proportions of CD8⁺ T, CD19⁺ B, CD3⁻CD56⁺ natural killer cell (NK), and CD3⁺ CD56⁺ natural killer T cell (NKT) were extremely low. Lymphocyte proliferation assay demonstrated that Tregs could inhibit the proliferation of CD8⁺ T cells more effectively than that of CD4⁺ T cells. Furthermore, the suppressive capacity of Tregs was correlated with Treg-to-PBMCs ratios.

Conclusions

We successfully established a technical protocol for manufacturing a large quantity of Tregs with high efficiency in vitro. The expanded Tregs have a steady FOXP3 expression and exhibited a potent immune suppression, which might have great significance in adoptive Treg therapy for treating graft-versus-host disease and autoimmune diseases.

Understanding the role of therapeutic plasma exchange in COVID-19: preliminary guidance and practices

BACKGROUND AND OBJECTIVES

Cytokine release syndrome in COVID-19 is due to a pathological inflammatory response of raised cytokines. Removal of these cytokines by therapeutic plasma exchange (TPE) prior to end-organ damage may improve clinical outcomes. This manuscript is intended to serve as a preliminary guidance document for application of TPE in patients with severe COVID-19.

MATERIAL AND METHODS

The available literature pertaining to the role of TPE for treatment of COVID-19 patients was reviewed to guide optimal management. It included indication, contraindication, optimal timing of initiation and termination of TPE, vascular access and anticoagulants, numbers and mode of procedures, outcome measures and adverse events.

RESULTS

Out of a total of 78 articles, only 65 were directly related to the topic. From these 65, only 32 were acceptable as primary source, while 33 were used as supporting references. TPE in critically ill COVID-19 patients may be classified under ASFA category III grade 2B. The early initiation of TPE for 1-1·5 patient's plasma volume with fresh frozen plasma, or 4-5% albumin or COVID-19 convalescent plasma as replacement fluids before multiorgan failure, has better chances of recovery. The number of procedures can vary from three to nine depending on patient response.

CONCLUSION

TPE in COVID-19 patients may help by removing toxic cytokines, viral particles and/or by correcting coagulopathy or restoring endothelial membrane. Severity score (SOFA & APACHE II) and cytokine levels (IL-6, C-reactive protein) can be used to execute TPE therapy and to monitor response in COVID-19 patients.

Regulation of CTLA-4 and PD-L1 Expression in Relapsing-Remitting Multiple Sclerosis Patients after Treatment with Fingolimod, IFNβ-1α, Glatiramer Acetate, and Dimethyl Fumarate Drugs

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system (CNS) that is characterized by inflammation which typically results in significant impairment in most patients. Immune checkpoints act as co-stimulatory and co-inhibitory molecules and play a fundamental role in keeping the equilibrium of the immune system. Cytotoxic T-lymphocyte antigen-4 (CTLA-4) and Programmed death-ligand 1 (PD-L1), as inhibitory immune checkpoints, participate in terminating the development of numerous autoimmune diseases, including MS. We assessed the CTLA-4 and PD-L1 gene expression in the different cell types of peripheral blood mononuclear cells of MS patients using single-cell RNA-seq data. Additionally, this study outlines how CTLA-4 and PD-L1 expression was altered in the PBMC samples of relapsing-remitting multiple sclerosis (RRMS) patients compared to the healthy group. Finally, it investigates the impact of various MS-related treatments in the CTLA-4 and PD-L1 expression to restrain autoreactive T cells and stop the development of MS autoimmunity.

T helper cell immunity in pregnancy and influence on autoimmune disease progression

Pregnancy presents the maternal immune system with a unique immunological challenge since it has to defend against pathogens while tolerating paternal allo-antigens expressed by fetal tissues. T helper (Th) cells play a central role in modulating immune responses and recent advances have defined distinct contributions of various Th cell subsets throughout each phase of human pregnancy, while dysregulation in Th responses show association with multiple obstetrical complications. In addition to localized decidual mechanisms, modulation of Th cell immunity during gestation is mediated largely by oscillations in sex hormone concentrations. Aberrant Th cell responses also underlie several autoimmune disorders while pregnancy-induced changes in the balance of Th cell immunity has been shown to exert favorable outcomes in the progression Th1 and Th17 driven autoimmune conditions only to be followed by post-partal exacerbations in disease.

Therapeutic Effect of Ginsenoside Rd on Experimental Autoimmune Encephalomyelitis Model Mice: Regulation of Inflammation and Treg/Th17 Cell Balance

Multiple sclerosis (MS) is an autoimmune inflammatory disease. Inflammatory infiltrates and demyelination of the CNS are the major characteristics of MS and its related animal model-experimental autoimmune encephalomyelitis (EAE). Immoderate autoimmune responses of Th17 cells and dysfunction of Treg cells critically contribute to the pathogenesis of MS and EAE. Our previous study showed that Ginsenoside Rd effectively ameliorated the clinical severity in EAE mice, but the mechanism remains unclear. In this study, we investigated the therapeutic effect of Ginsenoside Rd on EAE in vivo and in vitro and also explored the potential mechanisms for alleviating the injury of EAE. The results indicated that Ginsenoside Rd was effective for the treatment of EAE in mice and splenocytes. Ginsenoside Rd treatment on EAE mice ameliorated the severity of EAE and attenuated the characteristic signs of disease. Ginsenoside Rd displayed the therapeutic function to EAE by modulating inflammation and autoimmunity, via the downregulation of related proinflammatory cytokines IL-6 and IL-17, upregulation of inhibitory cytokines TGF-β and IL-10, and modulation of Treg/Th17 imbalance. And the Foxp3/RORγt/JAK2/STAT3 signaling was found to be associated with this protective function. In addition, analysis of gut microbiota showed that Ginsenoside Rd also had modulation potential on gut microbiota in EAE mice. Based on this study, we hypothesize that Ginsenoside Rd could be a potential and promising agent for the treatment of MS.

Effect of vitamin D supplementation on N-glycan branching and cellular immunophenotypes in MS

Objective

To investigate the effect of cholecalciferol (vitamin D3) supplementation on peripheral immune cell frequency and N‐glycan branching in patients with relapsing‐remitting multiple sclerosis (RRMS).

Methods

Exploratory analysis of high‐dose (20 400 IU) and low‐dose (400 IU) vitamin D3 supplementation taken every other day of an 18‐month randomized controlled clinical trial including 38 RRMS patients on stable immunomodulatory therapy (NCT01440062). We investigated cholecalciferol treatment effects on N‐glycan branching using L‐PHA stain (phaseolus vulgaris leukoagglutinin) at 6 months and frequencies of T‐, B‐, and NK‐cell subpopulations at 12 months with flow cytometry.

Results

High‐dose supplementation did not change CD3+ T cell subsets, CD19+ B cells subsets, and NK cells frequencies, except for CD8+ T regulatory cells, which were reduced in the low‐dose arm compared to the high‐dose arm at 12 months. High‐dose supplementation decreased N‐glycan branching on T and NK cells, measured as L‐PHA mean fluorescence intensity (MFI). A reduction of N‐glycan branching in B cells was not significant. In contrast, low‐dose supplementation did not affect N‐glycan branching. Changes in N‐glycan branching did not correlate with cell frequencies.

Interpretation

Immunomodulatory effect of vitamin D may involve regulation of N‐glycan branching in vivo. Vitamin D3 supplementation did at large not affect the frequencies of peripheral immune cells.

Immunometabolism: an overview and therapeutic prospects in autoimmune diseases

Metabolism is a critical immune regulator under physiologic and pathologic conditions. Culminating evidence has disentangled the contribution of distinct metabolic pathways, namely glucolysis, pentose phosphate, fatty acid oxidation, glutaminolysis, Krebs cycle and oxidative phosphorylation, in modulating innate and adaptive immune cells based on their activation/differentiation state. Metabolic aberrations and changes in the intracellular levels of specific metabolites are linked to the inflammatory phenotype of immune cells implicated in autoimmune disorders such as systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis and diabetes. Notably, targeting metabolism such as the mTOR by rapamycin, hexokinase by 2-deoxy-D-glucose, AMP-activated protein kinase by metformin, may be used to ameliorate autoimmune inflammation. Accordingly, research in immunometabolism is expected to offer novel opportunities for monitoring and treating immune-mediated diseases.

Treatment of experimental autoimmune encephalomyelitis with engineered bi-specific Foxp3+ regulatory CD4+ T cells

The use of autoantigen-specific regulatory T cells (Tregs) as a cellular therapy for autoimmune diseases is appealing. However, it is challenging to isolate and expand large quantity of Tregs expressing disease-relevant T-cell receptors (TCR). To overcome this problem, we used an approach aiming at redirecting the specificity of polyclonal Tregs through autoreactive TCR gene transfer technology. In this study, we examined whether Tregs engineered through retroviral transduction to express a TCR cross-reactive to two CNS autoantigens, myelin oligodendrocyte glycoprotein (MOG) and neurofilament-medium (NF-M), had a superior protective efficacy compared with Tregs expressing a MOG mono-specific TCR. We observed that engineered Tregs (engTregs) exhibited in vitro regulatory effects related to the antigenic specificity of the introduced TCR, and commensurate in potency with the avidity of the transduced TCR. In experimental autoimmune encephalomyelitis (EAE), adoptively transferred engTregs proliferated, and migrated to the CNS, while retaining FoxP3 expression. EngTregs expressing MOG/NF-M cross-reactive TCR had superior protective properties over engTregs expressing MOG-specific TCR in MOG-induced EAE. Remarkably, MOG/NF-M bi-specific TCR-engTregs also improved recovery from EAE induced by an unrelated CNS autoantigen, proteolipid protein (PLP). This study underlines the benefit of using TCRs cross-reacting towards multiple autoantigens, compared with mono-reactive TCR, for the generation of engTregs affording protection from autoimmune disease in adoptive cell therapy.

The potential of CD4+ regulatory T cells for the therapy of autoimmune diseases

Despite the considerable progress in the therapy of autoimmune pathologies, the existing methods are associated with the risk of serious adverse events. We think that regulatory T cells hold great promise for the therapy of disorders caused by a breakdown in immunological self-tolerance. This article aims at estimating the possible challenges facing Treg-based clinical approaches and offers solutions to the technical issues associated with the use of these cells in the therapy of autoimmune diseases.

Immunomodulatory function of Treg-derived exosomes is impaired in patients with relapsing-remitting multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease which is characterized by neuroaxonal degeneration in the central nervous system. Impaired function of regulatory T cells (Tregs) is believed to be an underlying pathogenic mechanism in MS. Tregs is able to release exosomes, which contain a considerable amount of protein and RNA. Exosomes are capable of transporting their content to other cells where the released content exerts biological functions. Here, we investigated whether Tregs exosomes of RRMS patients or healthy controls might regulate the proliferation or survival of T lymphocytes. Regulatory T cells derived from MS patients or healthy controls were cultured for 3 days and exosomes were purified from supernatants. Treg-derived exosomes were co-cultured with conventional T cells (Tconv). The percentages of Tconv proliferation and apoptosis were measured. Our findings showed that the percentage of proliferation suppression induced by exosomes in patients compared to healthy controls was 8.04 ± 1.17 and 12.5 ± 1.22, respectively, p value = 0.035. Moreover, the rate of Tconv apoptosis induced by exosome of MS patient was less than healthy controls (0.68 ± 0.12 vs. 1.29 ± 0.13; p value = 0.015). Overall, Treg-derived exosomes from MS patients and healthy controls suppressed the proliferation and induced apoptosis in Tconv. However, the effect of MS-derived exosomes was significantly less than healthy controls. Our results point to an alternative Treg inhibitory mechanism which might be important in immunopathogenesis of MS. Although, the cause of the exosomal defect in MS patients is unclear, manipulation of patients' Treg-derived exosomes to restore their suppressive activity might be considered as a potential therapeutic approach. Graphical abstract ᅟ.

Treatment of Experimental Autoimmune Encephalomyelitis by Sustained Delivery of Low-Dose IFN-α

Multiple sclerosis (MS) is a chronic autoimmune disease with no curative treatment. The immune regulatory properties of type I IFNs have led to the approval of IFN-β for the treatment of relapsing-remitting MS. However, there is still an unmet need to improve the tolerability and efficacy of this therapy. In this work, we evaluated the sustained delivery of IFN-α1, either alone or fused to apolipoprotein A-1 by means of an adeno-associated viral (AAV) system in the mouse model of myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis. These in vivo experiments demonstrated the prophylactic and therapeutic efficacy of the AAV-IFN-α or AAV-IFN-α fused to apolipoprotein A-1 vectors in experimental autoimmune encephalomyelitis, even at low doses devoid of hematological or neurologic toxicity. The sustained delivery of such low-dose IFN-α resulted in immunomodulatory effects, consisting of proinflammatory monocyte and T regulatory cell expansion. Moreover, encephalitogenic T lymphocytes from IFN-α-treated mice re-exposed to the myelin oligodendrocyte glycoprotein peptide in vitro showed a reduced proliferative response and cytokine (IL-17A and IFN-γ) production, in addition to upregulation of immunosuppressive molecules, such as IL-10, IDO, or PD-1. In conclusion, the results of the present work support the potential of sustained delivery of low-dose IFN-α for the treatment of MS and likely other T cell-dependent chronic autoimmune disorders.

Regulatory B and T lymphocytes in multiple sclerosis: friends or foes?

Current clinical experience with immunomodulatory agents and monoclonal antibodies in principle has established the benefit of depleting lymphocytic populations in relapsing–remitting multiple sclerosis (RRMS). B and T cells may exert multiple pro-inflammatory actions, but also possess regulatory functions making their role in RRMS pathogenesis much more complex. There is no clear correlation of Tregs and Bregs with clinical features of the disease. Herein, we discuss the emerging data on regulatory T and B cell subset distributions in MS and their roles in the pathophysiology of MS and its murine model, experimental autoimmune encephalomyelitis (EAE). In addition, we summarize the immunomodulatory properties of certain MS therapeutic agents through their effect on such regulatory cell subsets and their relevance to clinical outcomes.

[The treatment by expanded ex vivo autologous regulatory T-cells CD4+CD25+FoxP3+CD127low restores the balance of immune system in patients with remitting-relapsing multiple sclerosis]

AIM

To assess clinical efficacy and safety of the autologous (own) regulatory T-cells (Tregs)CD4+CD25+Foxp3+CD127low isolated from the blood of patients with remitting-relapsing multiple sclerosis. Patients with autoimmune diseases have the decreased number of peripheral Tregs (pTreg) and impaired suppressive ability. In order to restore levels of pTreg, it is possible to isolate precursor cells, enter expanded ex vivo autologous Treg cells and introduce an expanded amount of autologous cells as Treg vaccine.

MATERIAL AND METHODS

A method of ex vivo Tregs expansion by 30-40 times within 5-7 days has been developed. Expanded ex vivo Tregs are more than 90% CD4+CD25+Foxp3+CD127low and have high suppressor activity. Fourteen patients with remitting-relapsing multiple sclerosis were included in pilot studies.Ex vivoTregs were introduced subcutaneously in dosefrom 2.8 to 4.5 108 cell per injection. The duration of follow-up was 1 year.

RESULTS AND CONCLUSION

The numbers of pTregs in the blood of these patients elevated by 1.5-2 times. No adverse-effects, a decrease of relapses and stabilization of disability index were observed. It has been suggested that ex vivo expanded Tregs can compensate the impaired function of pTregs and can be used for adoptive immunotherapyof multiple sclerosis.

Small GTPase RAS in multiple sclerosis - exploring the role of RAS GTPase in the etiology of multiple sclerosis

RAS

signaling is involved in the development of autoimmunity in general. Multiple sclerosis (MS) is a T cell-mediated autoimmune disease of the central nervous system. It is widely recognized that a reduction of Foxp3+ regulatory T (Treg) cells is an immunological hallmark of MS, but the underlying mechanisms are unclear. In experimental autoimmune models, N-Ras and K-Ras inhibition triggers an anti-inflammatory effect up-regulating, via foxp3 elevation, the numbers and the functional suppressive properties of Tregs. Similarly, an increase in natural Tregs number during Experimental Autoimmune Encephalomyelitis (EAE) in R-RAS -/- mice results in attenuated disease. In humans, only KRAS GTPase isoform is involved in mechanism causing tolerance defects in rheumatoid arthritis (RA). T cells from these patients have increased transcription of KRAS (but not NRAS). RAS genes are major drivers in human cancers. Consequently, there has been considerable interest in developing anti-RAS inhibitors for cancer treatment. Despite efforts, no anti-RAS therapy has succeeded in the clinic. The major strategy that has so far reached the clinic aimed to inhibit activated Ras indirectly through blocking its post-translational modification and inducing its mis-localization. The disappointing clinical outcome of Farnesyl Transferase Inhibitors (FTIs) in cancers has decreased interest in these drugs. However, FTIs suppress EAE by downregulation of myelin-reactive activated T-lymphocytes and statins are currently studied in clinical trials for MS. However, no pharmacologic approaches to targeting Ras proteins directly have yet succeeded. The therapeutic strategy to recover immune function through the restoration of impaired Tregs function with the mounting evidences regarding KRAS in autoimmune mediated disorder (MS, SLE, RA, T1D) suggest as working hypothesis the direct targeting KRAS activation using cancer-derived small molecules may be clinically relevant.

ABBREVIATIONS

FTIs: Farnesyl Transferase Inhibitors; MS: Multiple Sclerosis; RRMS: Relapsing Remitting Multiple Sclerosis; PPMS: Primary Progressive Multiple Sclerosis; Tregs: regulatory T-cells; Foxp3: Forkhead box P3; EAE: Experimental Autoimmune Encephalomyelitis; T1D: Type 1 Diabete; SLE: Systemic Lupus Erythematosus; RA: Rheumatoid Arthritis; CNS: Central Nervous System; TMEV: Theiler's murine encephalomyelitis virus; FTS: farnesyl thiosalicylic acid; TCR: T-Cell Receptor; AIA: Adjuvant-induced Arthritis; EAN: experimental autoimmune neuritis; HVR: hypervariable region; HMG-CoA: 3-hydroxy-3-methylglutaryl coenzyme A reductase; PBMC: Peripheral Blood Mononuclear Cells.

Understanding Progressive Multifocal Leukoencephalopathy Risk in Multiple Sclerosis Patients Treated with Immunomodulatory Therapies: A Bird's Eye View

The increased use of newer potent immunomodulatory therapies for multiple sclerosis (MS), including natalizumab, fingolimod, and dimethyl fumarate, has expanded the patient population at risk for developing progressive multifocal leukoencephalopathy (PML). These MS therapies shift the profile of lymphocytes within the central nervous system (CNS) leading to increased anti-inflammatory subsets and decreased immunosurveillance. Similar to MS, PML is a demyelinating disease of the CNS, but it is caused by the JC virus. The manifestation of PML requires the presence of an active, genetically rearranged form of the JC virus within CNS glial cells, coupled with the loss of appropriate JC virus-specific immune responses. The reliability of metrics used to predict risk for PML could be improved if all three components, i.e., viral genetic strain, localization, and host immune function, were taken into account. Advances in our understanding of the critical lymphocyte subpopulation changes induced by these MS therapies and ability to detect viral mutation and reactivation will facilitate efforts to develop these metrics.

Circulating exosomes suppress the induction of regulatory T cells via let-7i in multiple sclerosis

Multiple sclerosis (MS) is a T cell-mediated autoimmune disease of the central nervous system. Foxp3⁺ regulatory T (Treg) cells are reduced in frequency and dysfunctional in patients with MS, but the underlying mechanisms of this deficiency are unclear. Here, we show that induction of human IFN-γ⁻IL-17A⁻Foxp3⁺CD4⁺ T cells is inhibited in the presence of circulating exosomes from patients with MS. The exosomal miRNA profile of patients with MS differs from that of healthy controls, and let-7i, which is markedly increased in patients with MS, suppresses induction of Treg cells by targeting insulin like growth factor 1 receptor (IGF1R) and transforming growth factor beta receptor 1 (TGFBR1). Consistently, the expression of IGF1R and TGFBR1 on circulating naive CD4⁺ T cells is reduced in patients with MS. Thus, our study shows that exosomal let-7i regulates MS pathogenesis by blocking the IGF1R/TGFBR1 pathway.

MiRNAs are small RNA molecules that can regulate gene expression. Here the authors show that expression of several exosomal miRNAs are altered in patients with multiple sclerosis, and that let-7i modulates regulatory T cell homeostasis to contribute to pathogenesis.

Experimental Autoimmune Encephalomyelitis Is Successfully Controlled by Epicutaneous Administration of MOG Plus Vitamin D Analog

Multiple sclerosis (MS) is an inflammatory and demyelinating disorder of the central nervous system (CNS). Experimental autoimmune encephalomyelitis (EAE) has been widely employed to evaluate new strategies to control MS, including procedures to induce immunological tolerance. Considering that skin exposure to protein antigens can induce tolerance and that vitamin D analogs conserve immunomodulatory potential and are less toxic, we investigated the efficacy of epicutaneous application of a myelin oligodendrocyte glycoprotein peptide (MOG_35–55) associated with paricalcitol (PARI) on EAE development. Three and 11 days after EAE induction, C57BL/6 mice were treated with an occlusive patch containing MOG plus PARI. Clinical parameters were daily assessed, whereas immunological and histological evaluations were performed during the acute EAE phase. MOG and MOG + PARI significantly controlled disease development reducing weight loss and clinical score. Moreover, MOG and MOG + PARI reduced the inflammatory process and preserved the myelin sheath in the CNS. High percentages of Foxp3⁺ regulatory T cells (Tregs) and lower MHCII fluorescence intensity in dendritic cells in draining lymph nodes were concomitantly observed. MOG + PARI association was, however, more efficient being able to reduce disease incidence and clinical scores more significantly than MOG or PARI alone. This experimental group also displayed a higher ratio between mRNA expression for Foxp3 and RORc and a higher percentage of Foxp3⁺ cells in the CNS. Modulation of activation markers observed in microglial cells eluted from EAE treated mice were confirmed by in vitro studies with the BV-2 microglial cell line. The results show that MOG + PARI association applied by an epicutaneous route controlled EAE development. Protective involved mechanisms include mainly a higher proportion of Tregs and also a direct immunomodulatory effect of PARI on microglial cells.

A B Cell-Driven Autoimmune Pathway Leading to Pathological Hallmarks of Progressive Multiple Sclerosis in the Marmoset Experimental Autoimmune Encephalomyelitis Model

The absence of pathological hallmarks of progressive multiple sclerosis (MS) in commonly used rodent models of experimental autoimmune encephalomyelitis (EAE) hinders the development of adequate treatments for progressive disease. Work reviewed here shows that such hallmarks are present in the EAE model in marmoset monkeys (Callithrix jacchus). The minimal requirement for induction of progressive MS pathology is immunization with a synthetic peptide representing residues 34–56 from human myelin oligodendrocyte glycoprotein (MOG) formulated with a mineral oil [incomplete Freund’s adjuvant (IFA)]. Pathological aspects include demyelination of cortical gray matter with microglia activation, oxidative stress, and redistribution of iron. When the peptide is formulated in complete Freund’s adjuvant, which contains mycobacteria that relay strong activation signals to myeloid cells, oxidative damage pathways are strongly boosted leading to more intensive pathology. The proven absence of immune potentiating danger signals in the MOG34–56/IFA formulation implies that a narrow population of antigen-experienced T cells present in the monkey’s immune repertoire is activated. This novel pathway involves the interplay of lymphocryptovirus-infected B cells with MHC class Ib/Caja-E restricted CD8+ CD56+ cytotoxic T lymphocytes.

Advances in the treatment of cutaneous lupus erythematosus

Lupus erythematosus (LE) is a multifactorial autoimmune disease with clinical manifestations of differing severity which may present with skin manifestations as primary sign of the disease (cutaneous lupus erythematosus, CLE) or as part of a disease spectrum (systemic lupus erythematosus, SLE). To date, no drugs are approved specifically for the treatment of CLE and only single agents have been applied in randomized controlled trials. Therefore, topical and systemic agents are used "off-label", primarily based on open-label studies, case series, retrospective analyses, and expert opinions. In contrast, several agents, such as hydroxychloroquine, chloroquine, cyclophosphamide, azathioprine, and belimumab, are approved for the treatment of SLE. Recent approaches in the understanding of the molecular pathogenesis of LE enabled the development of further new agents, which target molecules such as interleukin 6 (IL-6) and interferon (IFN). Only single trials, however, applied these new agents in patients with cutaneous involvement of the disease and/or included endpoints which evaluated the efficacy of these agents on skin manifestations. This article provides an updated review on new and recent approaches in the treatment of CLE.

Multiple functional therapeutic effects of TnP: A small stable synthetic peptide derived from fish venom in a mouse model of multiple sclerosis

The pathological condition of multiple sclerosis (MS) relies on innate and adaptive immunity. New types of agents that beneficially modify the course of MS, stopping the progression and repairing the damage appear promising. Here, we studied TnP, a small stable synthetic peptide derived from fish venom in the control of inflammation and demyelination in experimental autoimmune encephalomyelitis as prophylactic treatment. TnP decreased the number of the perivascular infiltrates in spinal cord, and the activity of MMP-9 by F4/80+ macrophages were decreased after different regimen treatments. TnP reduces in the central nervous system the infiltration of IFN-γ-producing Th1 and IL-17A-producing Th17 cells. Also, treatment with therapeutic TnP promotes the emergence of functional Treg in the central nervous system entirely dependent on IL-10. Therapeutic TnP treatment accelerates the remyelination process in a cuprizone model of demyelination. These findings support the beneficial effects of TnP and provides a new therapeutic opportunity for the treatment of MS.

Myeloid and T Cell-Derived TNF Protects against Central Nervous System Tuberculosis

Tuberculosis of the central nervous system (CNS-TB) is a devastating complication of tuberculosis, and tumor necrosis factor (TNF) is crucial for innate immunity and controlling the infection. TNF is produced by many cell types upon activation, in particularly the myeloid and T cells during neuroinflammation. Here we used mice with TNF ablation targeted to myeloid and T cell (MT-TNF^-/-) to assess the contribution of myeloid and T cell-derived TNF in immune responses during CNS-TB. These mice exhibited impaired innate immunity and high susceptibility to cerebral Mycobacterium tuberculosis infection, a similar phenotype to complete TNF-deficient mice. Further, MT-TNF^-/- mice were not able to control T cell responses and cytokine/chemokine production. Thus, our data suggested that collective TNF production by both myeloid and T cells are required to provide overall protective immunity against CNS-TB infection.

Circulating immune cells in multiple sclerosis

Circulating T and B lymphocytes contribute to the pathogenesis of the neuroinflammatory autoimmune disease, multiple sclerosis (MS). Further progress in the development of MS treatments is dependent upon a greater understanding of the immunological disturbances that underlie the disease. Analyses of circulating immune cells by flow cytometry have revealed MS-associated alterations in the composition and function of T and B cell subsets, including temporal changes associated with disease activity. Disturbances in circulating immune populations reflect those observed in the central nervous system and include skewing towards proinflammatory CD4⁺ and CD8⁺ T cells and B cells, greater proportions of follicular T helper cells and functional defects in the corresponding T and B regulatory subsets. Utilizing the analytical power of modern flow cytometers, researchers are now well positioned to monitor immunological changes associated with disease activity or intervention, describe immunological signatures with predictive value and identify targets for therapeutic drug development. This review discusses the contribution of various T and B lymphocyte subsets to MS pathogenesis, provides current and relevant phenotypical descriptions to assist in experimental design and highlights areas of future research.

Immune regulatory effects of high dose vitamin D3 supplementation in a randomized controlled trial in relapsing remitting multiple sclerosis patients receiving IFNβ; the SOLARIUM study

Multiple sclerosis (MS) is characterized by a disturbed immune homeostasis and low serum vitamin D levels are associated with an increased disease activity. While vitamin D has been hypothesized to promote the maintenance of immune homeostasis, vitamin D supplementation could be of benefit to patients with MS. The SOLAR study investigated the effects of high dose vitamin D₃ supplementation on clinical outcomes in a randomized controlled trial. Here we present the immune regulatory effects, investigated in the SOLARIUM sub-study. Thirty Dutch relapsing remitting (RR) MS patients treated with IFNβ-1a received high dose vitamin D₃ supplementation and 23 patients received placebo during a period of 48weeks. Lymphocytes were phenotypically characterized by flow cytometry and in vitro cytokine secretion was assessed in the presence or absence of 1,25(OH)₂D₃ using Luminex technology. Changes in immune regulatory parameters were determined within subjects as well as between treatment groups. The proportion of cells in the immune regulatory cell compartment (nTreg, iTreg and Breg) was not altered upon high dose vitamin D₃ supplementation. Proportions of T helper subsets were not affected by vitamin D₃, except for the proportion of IL4⁺ Th cells, which decreased in the placebo but not in the vitamin D₃ group. T cell cytokine secretion increased, most pronounced for IL5 and latency activated protein of TGFβ, in the placebo group but not in the vitamin D₃ group. Lymphocytes remained equally reactive to in vitro 1,25(OH)₂D₃. In conclusion, high dose vitamin D₃ supplementation did not result in a relative increase in lymphocytes with a regulatory phenotype. However, this study supports the hypothesis that vitamin D contributes to the maintenance of immune homeostasis by preventing further disturbance of the T cell compartment early in the disease course of MS.

The histone demethylase inhibitor GSK-J4 limits inflammation through the induction of a tolerogenic phenotype on DCs

As it has been established that demethylation of lysine 27 of histone H3 by the lysine-specific demethylase JMJD3 increases immune responses and thus elicits inflammation, we hypothesize that inhibition of JMJD3 may attenuate autoimmune disorders. We found that in vivo administration of GSK-J4, a selective inhibitor of JMJD3 and UTX, ameliorates the severity of experimental autoimmune encephalomyelitis (EAE). In vitro experiments revealed that the anti-inflammatory effect of GSK-J4 was exerted through an effect on dendritic cells (DCs), promoting a tolerogenic profile characterized by reduced expression of costimulatory molecules CD80/CD86, an increased expression of tolerogenic molecules CD103 and TGF-β1, and reduced secretion of proinflammatory cytokines IL-6, IFN-γ, and TNF. Adoptive transfer of GSK-J4-treated DCs into EAE mice reduced the clinical manifestation of the disease and decreased the extent of inflammatory CD4+ T cells infiltrating the central nervous system. Notably, Treg generation, stability, and suppressive activity were all exacerbated by GSK-J4-treated DCs without affecting Th1 and Th17 cell production. Our data show that GSK-J4-mediated modulation of inflammation is achieved by a direct effect on DCs and that systemic treatment with GSK-J4 or adoptive transfer of GSK-J4-treated DCs ex vivo may be promising approaches for the treatment of inflammatory and autoimmune disorders.

Piperine from black pepper inhibits activation-induced proliferation and effector function of T lymphocytes

Piperine is a major alkaloid component of black pepper (Piper nigrum Linn), which is a widely consumed spice. Here, we investigated the effect of piperine on mouse T lymphocyte activation. Piperine inhibited polyclonal and antigen-specific T lymphocyte proliferation without affecting cell viability. Piperine also suppressed T lymphocyte entry into the S and G2 /M phases of the cell cycle, and decreased expression of G1 -associated cyclin D3, CDK4, and CDK6. In addition, piperine inhibited CD25 expression, synthesis of interferon-γ, interleukin (IL)-2, IL-4, and IL-17A, and the generation of cytotoxic effector cells. The inhibitory effect of piperine on T lymphocytes was associated with hypophosphorylation of Akt, extracellular signal-regulated kinase, and inhibitor of κBα, but not ZAP-70. The ability of piperine to inhibit several key signaling pathways involved in T lymphocyte activation and the acquisition of effector function suggests that piperine might be useful in the management of T lymphocyte-mediated autoimmune and chronic inflammatory disorders.

Inhibiting neuroinflammation: The role and therapeutic potential of GABA in neuro-immune interactions

The central nervous system, once thought to be a site of immunological privilege, has since been found to harbour immunocompetent cells and to communicate with the peripheral nervous system. In the central nervous system (CNS), glial cells display immunological responses to pathological and physiological stimuli through pro- and anti-inflammatory cytokine and chemokine signalling, antigen presentation and the clearing of cellular debris through phagocytosis. While this neuroinflammatory signalling can act to reduce neuronal damage and comprises a key facet of CNS homeostasis, persistent inflammation or auto-antigen-mediated immunoreactivity can induce a positive feedback cycle of neuroinflammation that ultimately results in necrosis of glia and neurons. Persistent neuroinflammation has been recognised as a major pathological component of virtually all neurodegenerative diseases and has also been a focus of research into the pathology underlying psychiatric disorders. Thus, pharmacological strategies to curb the pathological effects of persistent neuroinflammation are of interest for many disorders of the CNS. Accumulating evidence suggests that GABAergic activities are closely bound to immune processes and signals, and thus the GABAergic neurotransmitter system might represent an important therapeutic target in modulating neuroinflammation. Here, we review evidence that inflammation induces changes in the GABA neurotransmitter system in the CNS and that GABAergic signalling exerts a reciprocal influence over neuroinflammatory processes. Together, the data support the hypothesis that the GABA system is a potential therapeutic target in the modulation of central inflammation.

The Critical Role of Induced CD4+ FoxP3+ Regulatory Cells in Suppression of Interleukin-17 Production and Attenuation of Mouse Orthotopic Lung Allograft Rejection

BACKGROUND

Lung transplantation is the only definitive therapy for many forms of end-stage lung disease. Studies have demonstrated the critical role of interleukin (IL)-17 in the development of lung rejection. Regulatory T cells (Tregs) are essential for the establishment and maintenance of immune tolerance.

METHODS

We established mouse orthotopic lung transplantation models to investigate the importance of IL-17 and IL-17-producing cell types in acute lung allograft rejection and the efficacy of the adoptive transfer of induced Tregs (iTregs) in attenuating pathologic lesions of lung allografts.

RESULTS

We found that the IL-17 produced by Th17 cells and γδ T cells might make the primary contributions to the progression of acute lung allograft rejection. Interleukin-17 deficiency decreased lung allograft lesions. Exogenous iTregs maintained their FoxP3 expression levels in lung allograft recipients. Induced Tregs therapy downregulated the expressions of Th17 and IL-17 γδ T cells and increased IL-10 production in the mouse orthotopic lung transplantation models. Moreover, the adoptive transfer of iTregs prolonged the survivals of the lung allografts and attenuated the progression of acute rejection.

CONCLUSION

These data suggested that the adoptive transfer of iTregs could suppress the Th17 cells and IL-17 γδ cells of the recipients, decrease the expression of IL-17, and attenuate the pathology of acute lung allograft rejection. Exogenous iTregs upregulated immunosuppressive factors, such as IL-10 and suppressed IL-17-producing cells, which was one of the pathways to play a role in protecting lung allografts.

In vivo maintenance of human regulatory T cells during CD25 blockade

Regulatory T cells (Tregs) mediate immune tolerance to self and depend on IL-2 for homeostasis. Treg deficiency, dysfunction, and instability are implicated in the pathogenesis of numerous autoimmune diseases. There is considerable interest in therapeutic modulation of the IL-2 pathway to treat autoimmunity, facilitate transplantation tolerance, or potentiate tumor immunotherapy. Daclizumab is a humanized mAb that binds the IL-2 receptor a subunit (IL-2R a or CD25) and prevents IL-2 binding. In this study, we investigated the effect of daclizumab-mediated CD25 blockade on Treg homeostasis in patients with relapsing-remitting multiple sclerosis. We report that daclizumab therapy caused an ~50% decrease in Tregs over a 52-wk period. Remaining FOXP3+ cells retained a demethylated Treg-specific demethylated region in the FOXP3 promoter, maintained active cell cycling, and had minimal production of IL-2, IFN- g, and IL-17. In the presence of daclizumab, IL-2 serum concentrations increased and IL-2R bg signaling induced STAT5 phosphorylation and sustained FOXP3 expression. Treg declines were not associated with daclizumab-related clinical benefit or cutaneous adverse events. These results demonstrate that Treg phenotype and lineage stability can be maintained in the face of CD25 blockade.

The anti-proliferative effect of cation channel blockers in T lymphocytes depends on the strength of mitogenic stimulation

Ion channels are crucially important for the activation and proliferation of T lymphocytes, and thus, for the function of the immune system. Previous studies on the effects of channel blockers on T cell proliferation reported variable effectiveness due to differing experimental systems. Therefore our aim was to investigate how the strength of the mitogenic stimulation influences the efficiency of cation channel blockers in inhibiting activation, cytokine secretion and proliferation of T cells under standardized conditions. Human peripheral blood lymphocytes were activated via monoclonal antibodies targeting the TCR-CD3 complex and the co-stimulator CD28. We applied the blockers of Kv1.3 (Anuroctoxin), KCa3.1 (TRAM-34) and CRAC (2-Apb) channels of T cells either alone or in combination with rapamycin, the inhibitor of the mammalian target of rapamycin (mTOR). Five days after the stimulation ELISA and flow cytometric measurements were performed to determine IL-10 and IFN-γ secretion, cellular viability and proliferation. Our results showed that ion channel blockers and rapamycin inhibit IL-10 and IFN-γ secretion and cell division in a dose-dependent manner. Simultaneous application of the blockers for each channel along with rapamycin was the most effective, indicating synergy among the various activation pathways. Upon increasing the extent of mitogenic stimulation the anti-proliferative effect of the ion channel blockers diminished. This phenomenon may be important in understanding the fine-tuning of T cell activation.

Change of Th17 Lymphocytes and Treg/Th17 in Typical and Atypical Optic Neuritis

Background

Typical and atypical optic neuritis (ON) are two clinical types of autoimmune inflammatory diseases of the optic nerve that causes acute vision loss, and are difficult to distinguish in their early stages. The disturbance in the balance of Th17 and Treg lymphocytes is thought to play an essential role in these autoimmune inflammatory diseases.

Objectives

To detect the clinical relevance of Th17 and Treg in peripheral blood and the ratio of Treg/Th17 in patients with typical and atypical ON. To determine whether analysis of Th17 and Treg lymphocytes will provides insights into the different disease phenotypes of typical and atypical ON.

Methods

We studied a consecutive series of patients aged 14–70 years who presented to our neurological department with typical ON (n = 30) or atypical ON (n = 33) within 4 weeks of their acute attacks. Routine clinical tests and ophthalmological examination were performed in all patients. Blood samples were collected from untreated patients and from gender- and age-matched healthy controls (n = 30). The proportion of peripheral blood Th17 cells and Treg cells was determined by flow cytometry.

Results

Patients with atypical ON had a higher proportion of Th17 cells than patients with typical ON (3.61±1.56 vs 2.55±1.74, P<0.01) or controls (1.45±0.86, P<0.01). The proportion of Th17 cells in patients with typical ON was also markedly higher than in controls (P<0.01). The mean percentage of Treg cells in atypical ON (6.31±2.11) and typical ON (6.80±2.00) were significantly lower when compared to controls (8.29±2.32, both P<0.01). No significant difference in Treg frequency was observed between typical ON and atypical ON (p>0.05).

Conclusions

The frequency of Th17 cells is higher in atypical ON than typical ON, and patients with atypical ON have a greater imbalance of pro-inflammatory and regulatory cells than patients with typical ON when compared with controls. These changes are indicative of distinct pathological mechanisms and may provide useful information to distinguish typical and atypical ON.

Increased serum level of IL-37 in patients with multiple sclerosis and neuromyelitis optica

Multiple sclerosis (MS) is a common autoimmune disease of central nervous system in which neurodegenerative and inflammatory mechanisms cause alternate neurological impairments. Many inflammatory and anti-inflammatory cytokines were suggested as contributor in MS pathogenesis, and the balance between these opposing cytokines can regulate MS severity. IL-37, an anti-inflammatory cytokine, is the most recently identified member of IL-1 family, which acts as a natural inhibitor of innate immunity. However, the role of IL-37 in MS has not investigated so far. Therefore, in this study, we aimed to measure serum level of IL-37 in patients with relapsing remitting multiple sclerosis (RRMS) and neuromyelitis optica (NMO). In a case-control study, plasma was collected from healthy controls (n = 49) and also patients with RRMS (n = 122) and NMO (n = 31). Serum level measurement of IL-37 was performed using enzyme-linked immunoassay (ELISA) method. The serum levels of IL-37 were 247.46 ± 74.02 and 312.00 ± 86.72 and 114.63 ± 20.58 in RRMS and NMO patients and healthy controls, respectively, showing statistically significant difference between them (P = 0.00). Furthermore, we found a positive correlation between the serum levels of IL-37 and EDSS of patients (r = +0.31 and P = 0.00). In summary, the serum level of IL-37 was found to be significantly increased in MS patients compared to healthy controls. Furthermore, the mean serum level of IL-37 was correlated with disease severity. This suggests that IL-37 may be part of a feed-back loop to control underlying inflammation in MS pathogenesis. However, further studies will be required to indicate exact role of IL-37 in the MS pathomechanisms.

MALT1 is an intrinsic regulator of regulatory T cells

Regulatory T cells (Tregs) are crucial for the maintenance of immunological self-tolerance and their absence or dysfunction can lead to autoimmunity. However, the molecular pathways that govern Treg biology remain obscure. In this study, we show that the nuclear factor-κB signalling mediator mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) is an important novel regulator of both Tregs originating in the thymus (‘natural’ or nTregs) and Tregs induced to differentiate from naive thymocyte helper (Th) cells in the periphery (‘induced’ or iTregs). Our examination of mice deficient for MALT1 revealed that these mutants have a reduced number of total Tregs. In young Malt1^−/− mice, nTregs are totally absent and iTreg are diminished in the periphery. Interestingly, total Treg numbers increase in older Malt1^−/− mice as well as in Malt1^−/− mice subjected to experimentally induced inflammation. iTregs isolated from WT and Malt1^−/− mice were indistinguishable with respect to their ability to suppress the activities of effector T cells, but Malt1^−/− iTregs expressed higher levels of Toll-like receptor (TLR) 2. Treatment of WT and Malt1^−/− Th cells in vitro with the TLR2 ligand Pam3Cys strongly enhanced the induction and proliferation of Malt1^−/− iTregs. Our data suggest that MALT1 supports nTreg development in the thymus but suppresses iTreg induction in the periphery during inflammation. Our data position MALT1 as a key molecule that contributes to immune tolerance at steady-state while facilitating immune reactivity under stress conditions.

R-flurbiprofen attenuates experimental autoimmune encephalomyelitis in mice

R-flurbiprofen is the non-cyclooxygenase inhibiting R-enantiomer of the non-steroidal anti-inflammatory drug flurbiprofen, which was assessed as a remedy for Alzheimer's disease. Because of its anti-inflammatory, endocannabinoid-modulating and antioxidative properties, combined with low toxicity, the present study assessed R-flurbiprofen in experimental autoimmune encephalomyelitis (EAE) models of multiple sclerosis in mice. Oral R-flurbiprofen prevented and attenuated primary progressive EAE in C57BL6/J mice and relapsing-remitting EAE in SJL mice, even if the treatment was initiated on or after the first flare of the disease. R-flurbiprofen reduced immune cell infiltration and microglia activation and inflammation in the spinal cord, brain and optic nerve and attenuated myelin destruction and EAE-evoked hyperalgesia. R-flurbiprofen treatment increased CD4(+)CD25(+)FoxP3(+) regulatory T cells, CTLA4(+) inhibitory T cells and interleukin-10, whereas the EAE-evoked upregulation of pro-inflammatory genes in the spinal cord was strongly reduced. The effects were associated with an increase of plasma and cortical endocannabinoids but decreased spinal prostaglandins, the latter likely due to R to S inversion. The promising results suggest potential efficacy of R-flurbiprofen in human MS, and its low toxicity may justify a clinical trial.