Inhibition of Interferon Regulatory Factor 4 Suppresses Th1 and Th17 Cell Differentiation and Ameliorates Experimental Autoimmune Encephalomyelitis

Interferon regulatory factor 4 plays a pivotal role in the development of aGVHD-associated colitis

Interferon regulatory factor 4 (IRF4) is a master transcription factor that regulates T helper cell (Th) differentiation. It interacts with the Basic leucine zipper transcription factor, ATF-like (BATF), depletion of which in CD4+ T cells abrogates acute graft-versus-host disease (aGVHD)-induced colitis. Here, we investigated the immune-regulatory role of Irf4 in a mouse model of MHC-mismatched bone marrow transplantation. We found that recipients of allogenic Irf4-/- CD4+ T cells developed less GVHD-related symptoms. Transcriptome analysis of re-isolated donor Irf4-/- CD4+ T helper (Th) cells, revealed gene expression profiles consistent with loss of effector T helper cell signatures and enrichment of a regulatory T cell (Treg) gene expression signature. In line with these findings, we observed a high expression of the transcription factor BTB and CNC homolog 2; (BACH2) in Irf4-/- T cells, which is associated with the formation of Treg cells and suppression of Th subset differentiation. We also found an association between BACH2 expression and Treg differentiation in patients with intestinal GVHD. Finally, our results indicate that IRF4 and BACH2 act as counterparts in Th cell polarization and immune homeostasis during GVHD. In conclusion, targeting the BACH2/IRF4-axis could help to develop novel therapeutic approaches against GVHD.

MAP kinase inhibitor PD98059 regulates Th1, Th9, Th17, and natural T regulatory cells in an experimental autoimmune encephalomyelitis mouse model of multiple sclerosis

Experimental autoimmune encephalitis (EAE), an animal model of multiple sclerosis (MS), provides significant insights into the mechanisms that initiate and drive autoimmunity. MS is a chronic autoimmune disease of the central nervous system, characterized by inflammatory infiltration associated with demyelination. T lymphocyte cells play a crucial role in MS, whereas natural T regulatory (nTreg) cells prevent autoimmune inflammation by suppressing lymphocyte activity. This study sought to investigate the role of PD98059, a selective MAP kinase inhibitor, in Th1, Th9, Th17, and nTreg cells using the SJL/J mouse model of EAE. Following EAE development, the mice were intraperitoneally administered PD98059 (5 mg/kg for two weeks) daily. We evaluated the effects of PD98059 on Th1 (IFN-γ and T-bet), Th9 (IL-9 and IRF4), Th17 (IL-17A and RORγT), and nTreg (FoxP3 and Helios) cells in the spleen using flow cytometry. Moreover, we explored the effects of PD98059 on the IFN-γ, T-bet, IL-9, IRF4, IL-17A, RORγT, FoxP3, and Helios mRNA and protein levels in brain tissues using qRT-PCR and Western blot analyses. PD98059 treatment significantly decreased the proportion of CD4+IFN-γ+, CD4+T-bet+, CD4+IL-9+, CD4+IRF4+, CD4+IL-17A+, CD4+RORγT+, CD4+IL-17A+, and CD4+RORγT+ cells while increasing that of CD4+FoxP3+ and CD4+Helios+ cells. In addition, PD98059 administration decreased the mRNA and protein levels of IFN-γ, T-bet, IL-9, IRF4, IL-17A, and RORγT but increased those of FoxP3 and Helios in the brain tissue of EAE mice. Our findings suggest that PD98059 corrects immune dysfunction in EAE mice, which is concurrent with the modulation of multiple signaling pathways.

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.

Dendritic Cells as a Nexus for the Development of Multiple Sclerosis and Models of Disease

Multiple sclerosis (MS) results from an autoimmune attack on the central nervous system (CNS). Dysregulated immune cells invade the CNS, causing demyelination, neuronal and axonal damage, and subsequent neurological disorders. Although antigen-specific T cells mediate the immunopathology of MS, innate myeloid cells have essential contributions to CNS tissue damage. Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that promote inflammation and modulate adaptive immune responses. This review focuses on DCs as critical components of CNS inflammation. Here, evidence from studies is summarized with animal models of MS and MS patients that support the critical role of DCs in orchestrating CNS inflammation.

Immunogenomic-Based Analysis of Hierarchical Clustering of Diffuse Large Cell Lymphoma

Diffuse large B cell lymphoma (DLBCL) is one of the most usual types of adult lymphoma with heterogeneousness in histological morphology, prognosis, and clinical indications. Prior to this, several studies were carried out to determine the DLBCL subtype based on the analysis of the genome profile. However, classification based on assessment of genes related to the immune system has limited clinical significance for DLBCL. We systematically explored the DLBCL gene expression dataset and provided publicly available clinical information on patients with GEO. In this research, 928 DLBCL samples were applied, and we calculated 29 immune-related genomes' enrichment levels in each sample and stratified them into high immunity (Immunity_H, n = 135, 28.7%), moderate immunity (Immunity_M, n = 135, 28.7%), and low immunity (Immunity_L, n = 12, 2.6%) that was based on ssGSEA score. The ESTIMATE algorithm was used to calculate stromal scores (range 586.88 to 1982.43), immune scores, estimated scores (range 2,618.2 to 8,098.14), and tumor purity (range 0.216 to 0.976). All of them were significantly correlated with immune subtypes (Kruskal-Wallis test, p < 0.001). At the same time, the correlation of related genes was analyzed by immunohistochemistry staining. In addition, DLBCL cells were cultured in transfected and in vitro with siRNA to verify correlation analysis and gene expression. Finally, human peripheral blood lymphocytes were incubated with DLBCL cells and stained. Flow cytometry was applied to analyze genes' influence on immune function. By analysis, immune checkpoint and HLA gene expression levels were higher in the Immunity_H group (Kruskal-Wallis test, p < 0.05). The levels of Tfhs (follicular helper T cells), monocytes, CD8⁺ T cells, M1 macrophages, M2 macrophages, and CD4⁺ memory-activated T cells were the most excellent in Immunity_H, and the total survival rate was higher in the Immunity_L. Through analysis, IRF4 (MUM1) was identified by us as immunotherapeutic target and a potential prognostic marker for DLBCL, which was made sure by using molecular biology experimentations. To conclude, immunosignature made a connection between DLBCL subtypes playing a position in DLBCL prognostic stratification. Immunocharacteristics-related DLBCL subtypes' construction predicts expected patient results and supplies conceivable immunotherapy candida.

Nucleic Acids as Novel Therapeutic Modalities to Address Multiple Sclerosis Onset and Progression

The issue of treating Multiple Sclerosis (MS) begins with disease-modifying treatments (DMTs) which may cause lymphopenia, dyspnea, and many other adverse effects. Consequently, further identification and evaluation of alternative treatments are crucial to monitoring their long-term outcomes and hopefully, moving toward personalized approaches that can be translated into clinical treatments. In this article, we focused on the novel therapeutic modalities that alter the interaction between the cellular constituents contributing to MS onset and progression. Furthermore, the studies that have been performed to evaluate and optimize drugs' efficacy, and particularly, to show their limitations and strengths are also presented. The preclinical trials of novel approaches for multiple sclerosis treatment provide promising prospects to cure the disease with pinpoint precision. Considering the fact that not a single treatment could be effective enough to cover all aspects of MS treatment, additional researches and therapies need to be developed in the future. Since the pathophysiology of MS resembles a jigsaw puzzle, researchers need to put a host of pieces together to create a promising window towards MS treatment. Thus, a combination therapy encompassing all these modules is highly likely to succeed in dealing with the disease. The use of different therapeutic approaches to re-induce self-tolerance in autoreactive cells contributing to MS pathogenesis is presented. A Combination therapy using these tools may help to deal with the clinical disabilities and symptoms of the disease in the future.

TLR-4, TLR-5 and IRF4 are diagnostic markers of knee osteoarthritis in the middle-aged and elderly patients and related to disease activity and inflammatory factors

Expression and diagnostic value of serum toll-like receptor-4 (TLR-4), Toll-like receptor-5 (TLR-5) and interferon regulatory factor 4 (IRF4) in middle-aged and elderly patients with knee osteoarthritis (KOA) and their correlation with Interleukin 1β (IL-1β), interleukin-6 (IL-6), matrix metalloproteinase-1 and tumor necrosis factor-α (TNF-α) were investigated. Sixty-eight middle-aged and elderly patients with KOA in Puyang Hospital of Traditional Chinese Medicine were selected as the study group and 49 healthy people receiving physical examination were the control group. Levels of serum TLR-4, TLR-5, IRF4, IL-1β, IL-6, MMP-1 and TNF-α were measured by enzyme linked immunosorbent assay (ELISA). Correlation between the expression levels of serum TLR-4, TLR-5, IRF4 and K-L grades was determined by Spearman correlation analysis. The diagnostic efficacy of serum TLR-4, TLR-5 and IRF4 for KOA was analyzed by the receiver operator characteristics analysis (ROC). Expression of serum TLR-4, TLR-5 and IRF4 in the study group was significantly higher than those in the control group. The sensitivity and specificity of TLR-4 in the diagnosis of KOA were, respectively, 76.47 and 93.88%, those of TLR-5 were 73.29 and 87.76%, those of IRF4 were 72.06 and 95.92%, and those of TLR-4, TLR-5 and IRF4 were 94.12 and 97.96%. Expression of serum TLR-4, TLR-5 and IRF4 was significantly higher in the severe group than in the moderate group, and significantly higher in the moderate group than those the in mild group, and significantly higher in the mild group than those in the suspected mild group. Expression of TLR-4, TLR-5 and IRF4 in serum was positively correlated with the concentration of IL-1β, IL-6, MMP-1 and TNF-α, respectively (P<0.001). The combined detection of TLR-4, TLR-5 and IRF4 can be used for early diagnosis of KOA, and they are positively correlated with IL-1β and IL-6, MMP-1 and TNF-α.

Exacerbated Imiquimod-Induced Psoriasis-Like Skin Inflammation in IRF5-Deficient Mice

Interferon regulatory factors (IRFs) play diverse roles in the regulation of the innate and adaptive immune responses in various diseases. In psoriasis, IRF2 is known to be involved in pathogenesis, while studies on other IRFs are limited. In this study, we investigated the role of IRF5 in psoriasis using imiquimod-induced psoriasis-like dermatitis. Although IRF5 is known to play a critical role in the induction of proinflammatory cytokines by immune cells, such as dendritic cells (DCs), macrophages, and monocytes, IRF5 deficiency unexpectedly exacerbated psoriasiform skin inflammation. The interferon-α and tumor necrosis factor-α mRNA expression levels were decreased, while levels of Th17 cytokines including IL-17, IL-22, and IL-23 were increased in IRF5-deficient mice. Furthermore, IL-23 expression in DCs from IRF5-deficient mice was upregulated both in steady state and after toll-like receptor 7/8 agonist stimulation. Importantly, the expression of IRF4, which is also important for the IL-23 production in DCs, was augmented in DCs from IRF5-deficient mice. Taken together, our results suggest that IRF5 deficiency induces the upregulation of IRF4 in DCs followed by augmented IL-23 production, resulting in the amplification of Th17 responses and the exacerbation of imiquimod-induced psoriasis-like skin inflammation. The regulation of IRF4 or IRF5 expression may be a novel therapeutic approach to psoriasis.

Prevention and treatment of experimental autoimmune encephalomyelitis induced mice with 1, 25-dihydroxyvitamin D3

Multiple sclerosis (MS) is a complex inflammatory and demyelinating disease of the central nervous system (CNS) frequently starts in young adulthood. Demyelination, inflammatory and axonal damage in the CNS is the pathological hallmark of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. 1, 25-dihydroxyvitamin D₃ (Vitamin D₃) is involved in calcium regulation, phosphorus homeostasis, and bone mineralization. In addition, vitamin D₃ has potential inhibitory effects on immune cells in various inflammatory and autoimmunity disease. C57BL/6 female mice were divided into prevention groups (low, middle and high doses) and treatment groups (middle and high doses). Prevention groups received vitamin D₃ 2 weeks before EAE induction, and treatment groups were treated with vitamin D₃ simultaneous with EAE induction. Vitamin D₃ inhibits the development of EAE in a dose-dependent manner. Histological studies revealed reduced demyelination and limited infiltration into CNS, moreover vitamin D₃ increased the production of IL-4, IL-10, and TGF-β, while a significant reduction in the production of IFN-γ, IL-6, TNF-α, and IL-17 was observed. Flow cytometry results for CD4⁺ T cell subsets in compliance with ELISA cytokine assay results showed a significant decrease in the percentage of Th1 and Th17, but also a significant increase in the percentage of Th2 and Treg for middle and high dose vitamin D₃ treated mice. Real-time PCR results indicated that middle and high dose vitamin D₃ treatment reduced T-bet and ROR-γt expression, but enhanced GATA3 and Foxp3 expression. Real-Time PCR results in CNS for T cell subsets related cytokines and transcription factors supported the results of flow cytometry and ELISA. This study indicated that middle and high doses of vitamin D3 deviate the balance between Th1/Th2 and Th17/Treg to Th2 and Treg. Moreover, vitamin D3 could reduce the incidence and severity of EAE clinical disease.

Therapeutic Efficacy of Mesenchymal Stem Cells and Mesenchymal Stem Cells-derived Neural Progenitors in Experimental Autoimmune Encephalomyelitis

Background and Objectives

The goal of treatment for MS is to reduce the inflammation and induce the regeneration of degenerated axons. Considering the anti-inflammatory and regenerative capacity of mesenchymal stem cell (MSCs), in this study the therapeutic efficacy of allogeneic MSCs and MSCs-derived neural progenitor cells (MSCs-NPs) was investigated in cellular therapy of chronic experimental autoimmune encephalomyelitis (EAE).

Methods and Results

MSCs, MSCs-NPs and MSCs+MSCs-NP were administered intravenously to EAE mice on days 22, 29, and 36 post immunization. The levels of cytokines and PGE2 in sera or supernatant of in vitro cultured splenocytes derived from treated mice were measured by ELISA. The results of this study showed that in comparison to MSCs monotherapy, MSCs-NPs administration had a more profound capability of inhibiting the proliferation of pathogenic MOG_35–55-specific T cells, decreasing IFN-γ production and increasing anti-inflammatory IL-10 cytokine production. These findings could be explained by higher ability of in vitro cultured MSCs-NPs in production of PGE2 compared to MSCs. In line with these findings, while the administration of MSCs and MSCs-NPs significantly decreased the clinical scores of EAE in comparison with the untreated EAE group, MSCs-NPs were significantly more efficient in reducing clinical score compared to MSCs. Of interest, combined therapy with MSCs and MSCs-NPs did not provide any benefit over monotherapy with MSCs-NPs.

Conclusions

In comparison to MSCs, allogenic MSCs-NPs are more potent in the attenuation of EAE.

IL17/IL17RA as a Novel Signaling Axis Driving Mesenchymal Stem Cell Therapeutic Function in Experimental Autoimmune Encephalomyelitis

The therapeutic effect of mesenchymal stem cells (MSCs) in multiple sclerosis (MS) and the experimental autoimmune encephalomyelitis (EAE) model has been well described. This effect is, in part, mediated through the inhibition of IL17-producing cells and the generation of regulatory T cells. While proinflammatory cytokines such as IFNγ, TNFα, and IL1β have been shown to enhance MSCs immunosuppressive function, the role of IL17 remains poorly elucidated. The aim of this study was, therefore, to investigate the role of the IL17/IL17R pathway on MSCs immunoregulatory effects focusing on Th17 cell generation in vitro and on Th17-mediated EAE pathogenesis in vivo. In vitro, we showed that the immunosuppressive effect of MSCs on Th17 cell proliferation and differentiation is partially dependent on IL17RA expression. This was associated with a reduced expression level of MSCs immunosuppressive mediators such as VCAM1, ICAM1, and PD-L1 in IL17RA^-/- MSCs as compared to wild-type (WT) MSCs. In the EAE model, we demonstrated that while WT MSCs significantly reduced the clinical scores of the disease, IL17RA^-/- MSCs injected mice exhibited a clinical worsening of the disease. The disability of IL17RA^-/- MSCs to reduce the progression of the disease paralleled the inability of these cells to reduce the frequency of Th17 cells in the draining lymph node of the mice as compared to WT MSCs. Moreover, we showed that the therapeutic effect of MSCs was correlated with the generation of classical Treg bearing the CD4⁺CD25⁺Foxp3⁺ signature in an IL17RA-dependent manner. Our findings reveal a novel role of IL17RA on MSCs immunosuppressive and therapeutic potential in EAE and suggest that the modulation of IL17RA in MSCs could represent a novel method to enhance their therapeutic effect in MS.

The Effects of Probiotic Supplementation on Gene Expression Related to Inflammation, Insulin, and Lipids in Patients With Multiple Sclerosis: A Randomized, Double-Blind, Placebo-Controlled Trial

BACKGROUND

Limited data are available assessing the effects of probiotic supplementation on gene expression related to inflammation, insulin, and lipids in patients with multiple sclerosis (MS).

OBJECTIVES

The current study was conducted to assess the effects of probiotic supplementation on gene expression related to inflammation, insulin, and lipids in patients with MS.

METHODS

This randomized, double-blind, placebo-controlled clinical trial was performed among 40 patients with MS. Participants were randomly assigned into two groups to receive either a probiotic capsule containing Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium bifidum, and Lactobacillus fermentum (2 × 109 colony-forming units/g each; n = 20) or placebo (n = 20) for 12 weeks. Gene expression related to inflammation, insulin, and lipids was quantified in blood samples of patients with MS with the reverse transcription polymerase chain reaction (RT-PCR) method.

RESULTS

We found that compared with placebo, probiotic supplementation down-regulated gene expression of interleukin-8 (IL-8; p < 0.001) and tumor necrosis factor-alpha (TNF-α) mRNA (p < .001) in peripheral blood mononuclear cells of patients with MS. We did not observe any significant effect of probiotic supplementation on gene expression of interleukin-1 (IL-1), peroxisome proliferator-activated receptor gamma (PPAR-γ), or oxidized low-density lipoprotein receptor (LDLR) in peripheral blood mononuclear cells of patients with MS.

CONCLUSIONS

Overall, probiotic supplementation for 12 weeks in patients with MS significantly improved gene expression of IL-8 and TNF-α but did not influence IL-1, PPAR-γ, or LDLR.

The role of Th17 cells in auto-inflammatory neurological disorders

The role of T helper 17 (Th17) cells in auto-inflammatory neurological disorders such as Multiple Sclerosis (MS), Alzheimer's disease (AD), Parkinson's disease (PD) and schizophrenia has not been clarified completely. Th17-derived pro-inflammatory cytokines including IL-17, IL-21, IL-22, IL-23, GM-CSF, and IFN-γ have a critical role in the pathogenesis of these disorders. In this review, we demonstrate the role of Th17 cells and their related cytokines in the immunopathology of above-mentioned disorders to get a better understanding of neuroinflammatory mechanisms mediated by Th17 cells associated with events leading to neurodegeneration.

Vitamin D Counteracts an IL-23-Dependent IL-17A+IFN-γ+ Response Driven by Urban Particulate Matter

Urban particulate matter (UPM) air pollution and vitamin D deficiency are detrimentally associated with respiratory health. This is hypothesized to be due in part to regulation of IL-17A, which UPM is reported to promote. Here, we used a myeloid dendritic cell (DC)-memory CD4⁺ T cell co-culture system to characterize UPM-driven IL-17A⁺ cells, investigate the mechanism by which UPM-primed DCs promote this phenotype, and address evidence for cross-regulation by vitamin D. CD1c⁺ myeloid DCs were cultured overnight with or without a reference source of UPM and/or active vitamin D (1,25[OH]₂D₃) before they were co-cultured with autologous memory CD4⁺ T cells. Supernatants were harvested for cytokine analysis on Day 5 of co-culture, and intracellular cytokine staining was performed on Day 7. UPM-primed DCs increased the proportion of memory CD4⁺ T cells expressing the T helper 17 cell (Th17)-associated cytokines IL-17A, IL-17F, and IL-22, as well as IFN-γ, granulocyte-macrophage colony-stimulating factor, and granzyme B. Notably, a large proportion of the UPM-driven IL-17A⁺ cells co-expressed these cytokines, but not IL-10, indicative of a proinflammatory Th17 profile. UPM-treated DCs expressed elevated levels of il23 mRNA and increased secretion of IL-23p40. Neutralization of IL-23 in culture reduced the frequency of IL-17A⁺IFN-γ⁺ cells without affecting cell proliferation. 1,25(OH)₂D₃ counteracted the UPM-driven DC maturation and inhibited the frequency of IL-17A⁺IFN-γ⁺ cells, most prominently when DCs were co-treated with the corticosteroid dexamethasone, while maintaining antiinflammatory IL-10 synthesis. These data indicate that UPM might promote an inflammatory milieu in part by inducing an IL-23-driven proinflammatory Th17 response. Restoring vitamin D sufficiency may counteract these UPM-driven effects without obliterating important homeostatic immune functions.

Distinct Roles of Th17 and Th1 Cells in Inflammatory Responses Associated with the Presentation of Paucibacillary Leprosy and Leprosy Reactions

It is well established that helper T cell responses influence resistance or susceptibility to Mycobacterium leprae infection, but the role of more recently described helper T cell subsets in determining severity is less clear. To investigate the involvement of Th17 cells in the pathogenesis of leprosy, we determined the immune profile with variant presentations of leprosy. Firstly, IL-17A, IFN-γ and IL-10 were evaluated in conjunction with CD4⁺ T cell staining by confocal microscopy of lesion biopsies from tuberculoid (TT) and lepromatous leprosy (LL) patients. Secondly, inflammatory cytokines were measured by multiplex assay of serum samples from Multibacillary (MB, n = 28) and Paucibacillary (PB, n = 23) patients and household contacts (HHC, n = 23). Patients with leprosy were also evaluated for leprosy reaction occurrence: LR+ (n = 8) and LR- (n = 20). Finally, peripheral blood mononuclear cells were analysed by flow cytometry used to determine the phenotype of cytokine-producing cells. Lesions from TT patients were found to have more CD4⁺ IL-17A⁺ cells than those from LL patients. Higher concentrations of IL-17A and IL-1β were observed in serum from PB than MB patients. The highest serum IFN-γ concentrations were, however, detected in sera from MB patients that developed leprosy reactions (MB LR⁺ ). Together, these results indicate that Th1 cells were associated with both the PB presentation and also with leprosy reactions. In contrast, Th17 cells were associated with an effective inflammatory response that is present in the PB forms but were not predictive of leprosy reactions in MB patients.

Helminth Products Potently Modulate Experimental Autoimmune Encephalomyelitis by Downregulating Neuroinflammation and Promoting a Suppressive Microenvironment

A negative correlation between the geographical distribution of autoimmune diseases and helminth infections has been largely associated in the last few years with a possible role for such type of parasites in the regulation of inflammatory diseases, suggesting new pathways for drug development. However, few helminth-derived immunomodulators have been tested in experimental autoimmune encephalomyelitis (EAE), an animal model of the human disease multiple sclerosis (MS). The immunomodulatory activities of Taenia crassiceps excreted/secreted products (TcES) that may suppress EAE development were sought for. Interestingly, it was discovered that TcES was able to suppress EAE development with more potency than dexamethasone; moreover, TcES treatment was still effective even when inoculated at later stages after the onset of EAE. Importantly, the TcES treatment was able to induce a range of Th2-type cytokines, while suppressing Th1 and Th17 responses. Both the polyclonal and the antigen-specific proliferative responses of lymphocytes were also inhibited in EAE-ill mice receiving TcES in association with a potent recruitment of suppressor cell populations. Peritoneal inoculation of TcES was able to direct the normal inflammatory cell traffic to the site of injection, thus modulating CNS infiltration, which may work along with Th2 immune polarization and lymphocyte activation impairment to downregulate EAE development.

SH479, a Betulinic Acid Derivative, Ameliorates Experimental Autoimmune Encephalomyelitis by Regulating the T Helper 17/Regulatory T Cell Balance

CD4⁺ T helper cells, especially T helper 17 (T_H17) cells, combined with immune regulatory network dysfunction, play key roles in autoimmune diseases including multiple sclerosis (MS). Betulinic acid (BA), a natural pentacyclic triterpenoid, has been reported to be involved in anti-inflammation, in particular having an inhibitory effect on proinflammatory cytokine interleukin 17 (IL-17) and interferon-γ (IFN-γ) production. In this study, we screened BA derivatives and found a BA derivative, SH479, that had a greater inhibitory effect on T_H17 differentiation. Our further analysis showed that SH479 had a greater inhibitory effect on T_H17 and T_H1, and a more stimulatory effect on regulatory T (Treg) cells. To evaluate the effects of SH479 on autoimmune diseases in vivo, we employed the extensively used MS mouse model experimental autoimmune encephalomyelitis (EAE). Our results showed that SH479 ameliorated clinical and histologic signs of EAE in both prevention and therapeutic protocols by regulating the T_H17/Treg balance. SH479 dose-dependently reduced splenic lymphocyte proinflammatory factors and increased anti-inflammatory factors. Moreover, SH479 specifically inhibited splenic lymphocyte viability from EAE mice but not normal splenic lymphocyte viability. At the molecular level, SH479 inhibited T_H17 differentiation by regulating signal transducer and activator of transcription-3 (STAT3) phosphorylation, DNA binding activity, and recruitment to the Il-17a promoter in CD4⁺ T cells. Furthermore, SH479 promoted the STAT5 signaling pathway and inhibited the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway. Together, our data demonstrated that SH479 ameliorated EAE by regulating the T_H17/Treg balance through inhibiting the STAT3 and NF-κB pathways while activating the STAT5 pathway, suggesting that SH479 is a potential novel drug candidate for autoimmune diseases including MS.