Roles of T helper 17 cells and interleukin-17 in neuroautoimmune diseases with emphasis on multiple sclerosis and Guillain-Barré syndrome as well as their animal models

Emerging Roles of T Helper Cells in Non-Infectious Neuroinflammation: Savior or Sinner

CD4⁺ T cells, also known as T helper (Th) cells, contribute to the adaptive immunity both in the periphery and in the central nervous system (CNS). At least seven subsets of Th cells along with their signature cytokines have been identified nowadays. Neuroinflammation denotes the brain’s immune response to inflammatory conditions. In recent years, various CNS disorders have been related to the dysregulation of adaptive immunity, especially the process concerning Th cells and their cytokines. However, as the functions of Th cells are being discovered, it’s also found that their roles in different neuroinflammatory conditions, or even the participation of a specific Th subset in one CNS disorder may differ, and sometimes contrast. Based on those recent and contradictory evidence, the conflicting roles of Th cells in multiple sclerosis, Alzheimer’s disease, Parkinson’s disease, epilepsy, traumatic brain injury as well as some typical mental disorders will be reviewed herein. Research progress, limitations and novel approaches concerning different neuroinflammatory conditions will also be mentioned and compared.

Beneficial Effects of Celastrol on Immune Balance by Modulating Gut Microbiota in Experimental Ulcerative Colitis Mice

Ulcerative colitis (UC) is a chronic inflammatory bowel disease caused by many factors including colonic inflammation and microbiota dysbiosis. Previous studies have indicated that celastrol (CSR) has strong anti-inflammatory and immune-inhibitory effects. Here, we investigated the effects of CSR on colonic inflammation and mucosal immunity in an experimental colitis model, and addressed the mechanism by which CSR exerts the protective effects. We characterized the therapeutic effects and the potential mechanism of CSR on treating UC using histological staining, intestinal permeability assay, cytokine assay, flow cytometry, fecal microbiota transplantation (FMT), 16S rRNA sequencing, untargeted metabolomics, and cell differentiation. CSR administration significantly ameliorated the dextran sodium sulfate (DSS)-induced colitis in mice, which was evidenced by the recovered body weight and colon length as well as the decreased disease activity index (DAI) score and intestinal permeability. Meanwhile, CSR down-regulated the production of pro-inflammatory cytokines and up-regulated the amount of anti-inflammatory mediators at both mRNA and protein levels, and improved the balances of Treg/Th1 and Treg/Th17 to maintain the colonic immune homeostasis. Notably, all the therapeutic effects were exerted in a gut microbiota-dependent manner. Furthermore, CSR treatment increased the gut microbiota diversity and changed the compositions of the gut microbiota and metabolites, which is probably associated with the gut microbiota-mediated protective effects. In conclusion, this study provides the strong evidence that CSR may be a promising therapeutic drug for UC.

Th17 Cells in Viral Infections-Friend or Foe?

Th17 cells are recognized as indispensable in inducing protective immunity against bacteria and fungi, as they promote the integrity of mucosal epithelial barriers. It is believed that Th17 cells also play a central role in the induction of autoimmune diseases. Recent advances have evaluated Th17 effector functions during viral infections, including their critical role in the production and induction of pro-inflammatory cytokines and in the recruitment and activation of other immune cells. Thus, Th17 is involved in the induction both of pathogenicity and immunoprotective mechanisms seen in the host's immune response against viruses. However, certain Th17 cells can also modulate immune responses, since they can secrete immunosuppressive factors, such as IL-10; these cells are called non-pathogenic Th17 cells. Here, we present a brief review of Th17 cells and highlight their involvement in some virus infections. We cover these notions by highlighting the role of Th17 cells in regulating the protective and pathogenic immune response in the context of viral infections. In addition, we will be describing myocarditis and multiple sclerosis as examples of immune diseases triggered by viral infections, in which we will discuss further the roles of Th17 cells in the induction of tissue damage.

Bariatric Surgery-Associated Myelopathy

Bariatric surgery is gaining acceptance as an efficient treatment modality for adults and adolescents with morbid obesity. The early postbariatric period has the potential to induce an immunomodulatory imbalance due to the development or worsening of nutritional deficiencies, changes in hormonal balance (specifically after sleeve gastrectomy), and a shift in the proinflammatory cytokine profile along with a major change in the gut microbiome and permeability. These changes may induce encephalomyelitic T cell activity, change neural barrier permeability, and induce gut dysbioisis, favoring a proinflammatory metabolic profile. Such changes, in genetically prone individuals or those with additional risk factors, may lead to the development of myelopathy, particularly MS. Key Message: Postbariatric myelopathy is rare but should be considered in bariatric patients with relevant complaints in the postoperative period.

Microglial NLRP3 inflammasome activation in multiple sclerosis

Multiple sclerosis (MS) is a chronic, autoimmune and neuroinflammatory disease of the central nervous system (CNS) mediated by autoreactive T cells directed against myelin antigens. Although the crucial role of adaptive immunity is well established in MS, the contribution of innate immunity has only recently been appreciated. Microglia are the main innate immune cells of the CNS. Similar to other myeloid cells, microglia recognize both exogenous and host-derived endogenous danger signals through pattern recognition receptors (PRRs) localized on their cell surface such as Toll Like receptor 4, or in the cytosol such as NLRP3. The second one is the sensor protein of the multi-molecular NLRP3 inflammasome complex in activated microglia that promotes the maturation and secretion of proinflammatory cytokines, interleukin-1β and interleukin-18. Overactivation of microglia and aberrant activation of the NLRP3 inflammasome have been implicated in the pathogenesis of MS. Indeed, experimental data, together with post-mortem and clinical studies have revealed an increased expression of NLRP3 inflammasome complex elements in microglia and other immune cells. In this review, we focus on microglial NLRP3 inflammasome activation in MS. First, we overview the basic knowledge about MS, microglia and the NLRP3 inflammasome. Then, we summarize studies about microglial NLRP3 inflammasome activation in MS and its animal models. We also highlight experimental therapeutic approaches that target different steps of NLRP inflammasome activation. Finally, we discuss future research avenues and new methods in this rapidly evolving area.

Class I PI3K inhibitor ZSTK474 attenuates experimental autoimmune neuritis by decreasing the frequency of Th1/Th17 cells and reducing the production of proinflammatory cytokines

The Class I phosphatidylinositol 3-kinase inhibitor, 2-(2-difluoromethy lbenzimidazol-1-yl)-4,6-dimorpholino-1,3,5-triazine (ZSTK474), has anti-inflammatory and immunoregulatory properties. However, whether it can be used to treat Guillain-Barré syndrome (GBS)-a neuroinflammatory disorder-is unknown. We induced experimental autoimmune neuritis (EAN) in Lewis rats, an established model of GBS. Orally administered ZSTK474 decreased neurological deficits in the GBS model, as demonstrated by diminished inflammatory cell infiltration, and ameliorated demyelination of sciatic nerves. Additionally, ZSTK474 decreased the number of Th1/Th17 cells and levels of the proinflammatory cytokines interleukin (IL)-1α, IL-1β, IL-17, IL-23, interferon-γ, and tumor necrosis factor-α. We propose that the phosphoinositide 3-kinase/AKT/mammalian target of rapamycin complex 1 (PI3K/AKT/mTORC1) pathway likely contributed to the neuroprotective effect of ZSTK474. ZSTK474 effectively decreases the frequency of Th1/Th17 cells, thereby reducing the production of proinflammatory cytokines and successfully alleviating the symptoms of EAN. Thus, the neuroprotective effect of ZSTK474 indicates its potential utility as anti-inflammatory therapy for GBS.

IL-23 and IL-27 Levels in Serum are Associated with the Process and the Recovery of Guillain-Barré Syndrome

IL-23 and IL-27 are believed to be involved in the pathogenesis of Guillain-Barré syndrome (GBS). However, changes in these cytokines during the dynamic pathological and recovery processes of GBS are not well described. In the present study, plasma was collected from 83 patients with various stages of GBS, 70 patients with central nervous system demyelinating diseases,70 patients with other neurological diseases (OND) and 70 age- and sex-matched healthy volunteers. Serum levels of IL-23, IL-27, and Campylobacter jejuni (CJ) IgM were assessed using enzyme linked immunosorbent assay (ELISA). We found that serum IL-23 levels of patients during the acute phase of GBS were significantly higher followed by a decreasing trend during the recovery phase of the disease. Serum IL-27 levels significantly increased during the acute phase of GBS, and gradually increased during the recovery phase. Interestingly, both the severity and subtype of GBS were closely associated with the two cytokines. IL-23 levels were positively correlated with IL-27 levels, prognosis, and other clinical parameters. Our findings confirm that IL-23 may show pro-inflammatory effects, especially at the early stage of GBS. IL-27 appears to have a dual role in GBS, with initial pro-inflammatory effects, followed by anti-inflammatory properties during recovery.

Down-regulation of RORA gene expression in the blood of multiple sclerosis patients

Multiple sclerosis (MS) is an autoimmune disease characterized by recurrent episodes of demyelination and loss of oligodendrocytes. The demyelination process is caused by various subsets of CD4+ T cells with a Th1 and Th17 phenotype. The retinoid acid-related orphan receptor A (RORA) is expressed in Th17 cells and promote Th17 differentiation. In this study, we compared the expression level of RORA gene in the blood of 50 relapsing-remitting MS (RRMS) patients who were treated with IFN-β and 50 healthy controls by TaqMan Quantitative Real-Time PCR.We found that RORA expression was significantly down-regulated in MS patients compared with controls (P= 0.006). However, there was no significant correlation between RORA gene expression and Kurtzke Expanded Disability Status Scale (EDSS). Our findings suggest a possible contribution of IFN-β in the downregulation of RORA. In addition, RORA downregulation may be a potential indicator of positive response to interferon beta treatment of multiple sclerosis patients.

Serum CCL20 and its association with SIRT1 activity in multiple sclerosis patients

CCL20 is a potentially important component in the pathogenesis of multiple sclerosis (MS). SIRT1 exhibits a negative regulatory effect on a variety of inflammatory cytokines and can relieve experimental autoimmune encephalomyelitis. The association between the level of CCL20 and SIRT1 activity in MS patients has not been investigated. In the present study, blood samples were collected from 38 RRMS patients and 40 healthy controls. The serum CCL20 levels were measured by ELISA. SIRT1 activity was evaluated by fluorometric assay. We revealed elevated serum CCL20 concentrations in MS, and discovered an inverse correlation between CCL20 and SIRT1 activity in MS patients.

Quantitative proteomics reveals Piccolo as a candidate serological correlate of recovery from Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an autoimmune-mediated peripheral neuropathy of unknown cause. However, about a quarter of GBS patients have suffered a recent bacterial or viral infection, and axonal forms of the disease are especially common in these patients. Proteomics is a good methodological approach for the discovery of disease biomarkers. Until recently, most proteomics studies of GBS and other neurodegenerative diseases have focused on the analysis of the cerebrospinal fluid (CSF). However, serum represents an attractive alternative to CSF because it is easier to sample and has potential for biomarker discovery. The goal of this research was the identification of serum biomarkers associated with recovery from GBS. To address this objective, a quantitative proteomics approach was used to characterize differences in the serum proteome between a GBS patient and her healthy identical twin in order to lessen variations due to differences in genetic background, and with additional serum samples collected from unrelated GBS (N = 3) and Spinal Cord Injury (SCI) (N = 3) patients with similar medications. Proteomics results were then validated by ELISA using sera from additional GBS patients (N = 5) and healthy individuals (N = 3). All GBS and SCI patients were recovering from the acute phase of the disease. The results showed that Piccolo, a protein that is essential in the maintenance of active zone structure, constitutes a potential serological correlate of recovery from GBS. These results provided the first evidence for the Piccolo´s putative role in GBS, suggesting a candidate target for developing a serological marker of disease recovery.

Programmed Death Ligand 1 Plays a Neuroprotective Role in Experimental Autoimmune Neuritis by Controlling Peripheral Nervous System Inflammation of Rats

Programmed death 1 (PD-1; CD279), a member of the CD28 family, is an inhibitory receptor on T cells and is responsible for T cell dysfunction in infectious diseases and cancers. The ligand for PD-1, programmed death ligand 1 (PD-L1; also known as B7-H1, CD274), is a member of the B7 family. The engagement of PD-1 with programmed death ligand can downregulate autoreactive T cells that participate in multiple autoimmune diseases. Experimental autoimmune neuritis (EAN) is an animal model of Guillain-Barré syndrome, and the pathogenesis of EAN is mediated principally through T cells and macrophages. In this study, we investigated the effects of PD-L1 in EAN rats. For preventative and therapeutic management, we administered PD-L1, which successfully decreased the severity of EAN; it alleviated the neurologic course of EAN, as well as inhibited the infiltration of inflammatory cells and demyelination of sciatic nerves. Our data revealed that PD-L1 treatment inhibited lymphocyte proliferation and altered T cell differentiation by inducing decreases in IFN-γ⁺CD4⁺ Th1 cells and IL-17⁺CD4⁺ Th17 cells and increases in IL-4⁺CD4⁺ Th2 cells and Foxp3⁺CD4⁺ regulatory T cells. The expression levels of p-STAT3 and Foxp3 were significantly different in PD-L1-treated groups compared with the control group. Additionally, PD-L1 regulated the expression of Foxp3 and p-STAT3 in EAN, probably by inhibiting PI3K/AKT/mTOR signaling expression. In summary, PD-L1 is a potentially useful agent for the treatment of EAN because of its anti-inflammatory and neuroprotective effects.

Genes differentially expressed by methylprednisolone in vivo in CD4 T lymphocytes from multiple sclerosis patients: potential biomarkers

Intravenous methylprednisolone (IVMP) is the gold standard treatment in acute relapses of multiple sclerosis. Knowing the response to IVMP in advance could facilitate earlier selection of patients for subsequent courses of therapy. However, molecular mechanisms and changes in gene expression induced by methylprednisolone remain unknown. The aim of the study was to identify in vivo differentially expressed genes in relapsing-remitting multiple sclerosis patients after 3-6 days of treatment with IVMP. For this purpose, whole-genome transcription profiling of CD4+ T lymphocytes was performed before and after treatment with IVMP in 8 relapsing-remitting multiple sclerosis patients during relapse using Human GE 4x44K v2 microarrays. Differentially expressed genes were identified using a paired t test on GeneSpring v13.0 software. A P-value <0.001 and a twofold change were considered significant. Microarray data were confirmed using real-time PCR. Microarray revealed changes in gene expression: four genes were downregulated (B3GNT3, ZNF683, IFNG and TNF) and seven upregulated (DEFA4, CTSG, DEFA8P, AZU1, MPO, ELANE and PRTN3). Pathway analysis revealed the transforming growth factor-β signaling pathway to be affected. Comparison with previously published data on in vitro methylprednisolone-regulated genes showed that SMAD7, TNF and CHI3L1 were also downregulated in vivo in relapsing-remitting multiple sclerosis patients. In summary, we performed the first in vivo transcriptome analysis in CD4+ T lymphocytes before and after the treatment with IVMP in patients with multiple sclerosis. Identification of differentially expressed genes in patients receiving IVMP could improve our understanding of the molecular mechanisms underlying the therapeutic effects of IVMP and highlight potential biomarkers of the response to IVMP.

Dynamics of Th17 associating cytokines in Cryptosporidium parvum-infected mice

Cryptosporidium parvum commonly inhabits the intestinal tract of animals and humans and can cause acute watery diarrhea and weight loss. However, host immune responses to Cryptosporidium infections are not fully understood. IL-17 (also called IL-17A) is a pro-inflammatory cytokine of Th17 cells that plays a role in the host response to Cryptosporidium baileyi infection. The present study examined levels of IL-17-specific messenger RNA (mRNA) and Th17 associating cytokines in C. parvum-infected immune-suppressed BALB/c mice using real-time quantitative PCR (qPCR). Levels of IL-17 protein were determined by ELISA. The results showed that levels of IL-17 mRNA and Th17 cell-related cytokines, namely TGF-β, IL-6, STAT-3, RORγt, IL-22, TNF-α, and IL-23, were significantly increased (P < 0.05) in gut-associated lymphoid tissue (GALT) and spleen. IL-17 protein levels in GALT were also significantly increased (P < 0.05) after infection. The present study suggested that Th17 cells play a role in host-C. parvum interaction. These results could inform future studies of the immune response against C. parvum infection in transient immunosuppressed populations.

Follicular Helper CD4+ T Cells in Human Neuroautoimmune Diseases and Their Animal Models

Follicular helper CD4⁺ T (TFH) cells play a fundamental role in humoral immunity deriving from their ability to provide help for germinal center (GC) formation, B cell differentiation into plasma cells and memory cells, and antibody production in secondary lymphoid tissues. TFH cells can be identified by a combination of markers, including the chemokine receptor CXCR5, costimulatory molecules ICOS and PD-1, transcription repressor Bcl-6, and cytokine IL-21. It is difficult and impossible to get access to secondary lymphoid tissues in humans, so studies are usually performed with human peripheral blood samples as circulating counterparts of tissue TFH cells. A balance of TFH cell generation and function is critical for protective antibody response, whereas overactivation of TFH cells or overexpression of TFH-associated molecules may result in autoimmune diseases. Emerging data have shown that TFH cells and TFH-associated molecules may be involved in the pathogenesis of neuroautoimmune diseases including multiple sclerosis (MS), neuromyelitis optica (NMO)/neuromyelitis optica spectrum disorders (NMOSD), and myasthenia gravis (MG). This review summarizes the features of TFH cells, including their development, function, and roles as well as TFH-associated molecules in neuroautoimmune diseases and their animal models.

Berberine ameliorates TNBS induced colitis by inhibiting inflammatory responses and Th1/Th17 differentiation

Th1 and Th17 cells, and their associated cytokines, have been associated with the pathogenesis of Crohn's disease. Berberine (BBR), a compound long used in traditional Chinese medicines, has been reported to have therapeutic effects in treating experimental colitis. In this study, we show that BBR had a protective effect on mice with TNBS-induced colitis. BBR inhibited levels of IFN-γ, IL-17, IL-6, IL-1β and TNF-α both in the local colon and sera, and transiently increased levels of IL-22. BBR also markedly increased sIgA expression in the colon. BBR had pronounced effects on macrophage populations. Treatment with BBR adjusted the M2/M1 ratio. In addition, BBR exerted effects on adaptive immunity by suppressing numbers of Th1 and Th17 cells, as well as expression levels of their associated cytokines and transcriptional factors. BBR downregulated STAT3 and STAT1 phosphorylation, and inhibited phosphorylation of NF-kB. In vitro experiments showed that BBR inhibited the differentiation of Th17 and, to a lesser degree, Th1 cells, without affecting regulatory T cells. Therefore, we conclude that BBR plays a regulatory role in modulating the balance of immune responses in TNBS-induced colitis. Our study will help us understand the regulatory mechanisms exerted by BBR in the treatment of IBD.

Circulating levels of interleukin-35 in patients with multiple sclerosis: evaluation of the influences of FOXP3 gene polymorphism and treatment program

The regulatory T (Treg) cells play a major role in the control of the autoimmunity and inflammation, and IL-35 has been described as an immunosuppressive cytokine that is mainly produced by CD4(+)FOXP3(+) Treg cells. The aim of this study was to evaluate the serum levels of IL-35 and a single nucleotide polymorphism (SNP), rs3761548, in FOXP3 gene in patients with multiple sclerosis. The blood samples were collected from 140 multiple sclerosis (MS) patients (including 51 untreated and 89 treated patients) and 140 healthy subjects as a control group. The serum levels of IL-35 were measured by ELISA. The DNA was analyzed for SNP rs3761548 in FOXP3 gene using SSP-PCR. There was no significant difference between untreated MS patients and control group regarding the mean serum levels of IL-35, although this parameter was higher in untreated patients. However, the mean serum level of IL-35 in treated MS patients was significantly higher than that in the control group (P < 0.008). The mean serum levels of IL-35 in patients who were treated with interferon-β, methylprednisolone, or with the both interferon-β and methylprednisolone were significantly higher than that in the healthy group (P < 0.01, P < 0.01, and P < 0.2, respectively). The frequencies of AA and AC genotypes at rs3761548 in the FOXP3 gene were significantly higher in MS group as compared with healthy subjects (P < 0.05). The frequency of CC genotype at rs3761548 was significantly lower in the MS group in comparison with healthy control subjects (P < 0.001). Moreover, the frequency of A allele was significantly higher whereas the frequency of C allele was significantly lower in MS patients in comparison to healthy subjects (P < 0.001). The mean serum level of IL-35 was significantly lower in MS patients or healthy subjects with AA genotype as compared with those with CC genotype at rs3761548 in FOXP3 gene (P < 0.01 and P < 0.001, respectively). These results showed higher serum levels of IL-35 in treated MS patients representing that the benefit effects of treatment may in part performed through the upregulation of the IL-35 production. The SNP rs3761548 may influence the susceptibility to MS disease and the serum levels of IL-35.

Participation of interleukin 17A in neuroimmune interactions

Inflammation involving the helper T cell 17 (Th17) subset of lymphocytes has been implicated in a number of diseases that affect the nervous system. As the canonical cytokine of Th17 cells, interleukin 17A (IL-17A) is thought to contribute to these neuroimmune interactions. The main receptor for IL-17A is expressed in many neural tissues. IL-17A has direct effects on neurons but can also impact neural function via signaling to satellite cells and immune cells. In the central nervous system, IL-17A has been associated with neuropathology in multiple sclerosis, epilepsy syndromes and ischemic brain injury. Effects of IL-17A at the level of dorsal root ganglia and the spinal cord may contribute to enhanced nociception during neuropathic and inflammatory pain. Finally, IL-17A plays a role in sympathetic axon growth and regeneration of damaged axons that innervate the cornea. Given the widespread effects of IL-17A on neural tissues, it will be important to determine whether selectively mitigating the damaging effects of this cytokine while augmenting its beneficial effects is a possible strategy to treat inflammatory damage to the nervous system.

Mitigated Tregs and augmented Th17 cells and cytokines are associated with severity of experimental autoimmune neuritis

Experimental autoimmune neuritis (EAN), an animal model of human Guillain-Barré syndrome, has long been considered as a T helper (Th) 1 cell-mediated autoimmune disorder. However, deficiency of IFN-γ, a signature Th1 cytokine, aggravated EAN, with features of elevated production of IL-17A, despite an alleviated systemic Th1 immune response. We hypothesized that Th17 cells and their cytokines might play a pathogenic role in EAN. To further clarify the roles of these Th and regulatory T cell (Treg) cytokines in the pathogenesis of EAN and their interrelationship, we investigated the expression of Th1/Th2/Th17/Treg cytokines in EAN in this study. We found that the levels of Th17 cells and IL-17A in cauda equina (CE)-infiltrating cells and splenic mononuclear cells (MNCs) as well as in serum paralleled the disease evolution, which increased progressively during the initiation stage and reached higher value at the peak of EAN. The same pattern was also noticed for the expression of IL-22. The diverse expression profiles of FoxP3, IL-17 receptors A and C were seen in CE-infiltrating cells and splenic MNCs in EAN. These findings indicate a major pro-inflammatory role of Th17 cells and IL-17A in the pathogenesis of EAN. Therapeutic interventions may be focused upon inhibiting Th17 cells and their cytokines in the early phase of EAN, so as to delay and suppress clinical signs of the disease, which has relevance for future studies on pathogenesis and treatment of GBS in humans.

Copaiba oil suppresses inflammatory cytokines in splenocytes of C57Bl/6 mice induced with experimental autoimmune encephalomyelitis (EAE)

Experimental autoimmune encephalomyelitis (EAE) is a murine autoimmune disease used to study multiple sclerosis. We have investigated the immunomodulatory effects of copaiba oil (100, 50 and 25 µg/mL) on NO, H₂O₂, TNF-α, IFN-γ and IL-17 production in cultured cells from EAE-mice. Copaiba oil (100 µg/mL) inhibited H₂O₂, NO, IFN-γ TNF-α and IL-17 production spontaneously or after ConA and MOG_35–55 stimulation. It is suggested that copaiba oil acts on the mechanism of development of EAE by IFN-γ, IL-17 and TNF-α inhibition, modulating the immune response on both Th1 and Th17 cells.

TGF-β signaling initiated in dendritic cells instructs suppressive effects on Th17 differentiation at the site of neuroinflammation

While the role of Transforming Growth Factor β (TGF-β) as an intrinsic pathway has been well established in driving de novo differentiation of Th17 cells, no study has directly assessed the capacity of TGF-β signaling initiated within dendritic cells (DCs) to regulate Th17 differentiation. The central finding of this study is the demonstration that Th17 cell fate during autoimmune inflammation is shaped by TGF-β extrinsic pathway via DCs. First, we provide evidence that TGF-β limits at the site of inflammation the differentiation of highly mature DCs as a means of restricting Th17 cell differentiation and controlling autoimmunity. Second, we demonstrate that TGF-β controls DC differentiation in the inflammatory site but not in the priming site. Third, we show that TGF-β controls DC numbers at a precursor level but not at a mature stage. While it is undisputable that TGF-β intrinsic pathway drives Th17 differentiation, our data provide the first evidence that TGF-β can restrict Th17 differentiation via DC suppression but such a control occurs in the site of inflammation, not at the site of priming. Such a demarcation of the role of TGF-β in DC lineage is unprecedented and holds serious implications vis-à-vis future DC-based therapeutic targets.

Immunomodulatory activity of interferon-beta

Multiple sclerosis (MS) is a complex disorder of the central nervous system that appears to be driven by a shift in immune functioning toward excess inflammation that results in demyelination and axonal loss. Beta interferons were the first class of disease-modifying therapies to be approved for patients with MS after treatment with this type I interferon improved the course of MS on both clinical and radiological measures in clinical trials. The mechanism of action of interferon-beta appears to be driven by influencing the immune system at many levels, including antigen-presenting cells, T cells, and B cells. One effect of these interactions is to shift cytokine networks in favor of an anti-inflammatory effect. The pleiotropic mechanism of action may be a critical factor in determining the efficacy of interferon-beta in MS. This review will focus on select immunological mechanisms that are influenced by this type I cytokine.

Enhancement of CD147 on M1 macrophages induces differentiation of Th17 cells in the lung interstitial fibrosis

Lung interstitial fibrosis is a chronic lung disease, and few effective therapies are available to halt or reverse the progression of the disease. In murine and human lung fibrosis, the expression of CD147 is increased. However, the role of CD147 in lung fibrosis has not been identified, and it remains to be determined whether lung fibrosis would be improved by decreasing the expression of CD147. A murine bleomycin-induced lung interstitial fibrosis model was used in the experiments, and HAb18 mAbs and CsA were administered during the induction of lung fibrosis. In our study, we found that the HAb18 mAbs markedly reduced the collagen score and down-regulated M1 macrophages and Th17 cells. In vitro, flow cytometry analysis showed that M1 macrophages induced higher Th17 differentiation than M2 macrophages. After treatment with HAb18 mAbs or after reducing the expression of CD147 by lentivirus interference in M1 macrophages, the level of Th17 cells were significantly inhibited. In conclusion, HAb18 mAbs or CsA treatment ameliorates lung interstitial fibrosis. CD147 promoted M1 macrophage and induced the differentiation of Th17 cells in lung interstitial fibrosis, perhaps by regulating some cytokines such as IL-6, IL-1β, IL-12 and IL-23. These results indicated that CD147 may play an important role in the development of lung interstitial fibrosis.

Immunomodulatory effects of licochalcone A on experimental autoimmune encephalomyelitis

OBJECTIVES

Experimental autoimmune encephalomyelitis (EAE) is a murine autoimmune disease used to study multiple sclerosis. Herein, we have investigated the immunomodulatory effect of licochalcone A (LicoA) on NO, H2 O2 , tumour necrosis factor-alpha (TNF-α), interferon gamma (IFN-γ) and IL-17 production in cultured cells from EAE mice.

METHODS

EAE was induced in C57Bl/6 mice with myelin oligodendrocyte glycoprotein peptide (MOG35-55 ). LicoA was isolated from the roots of Glycyrrhiza inflata. Splenocytes were obtained from EAE mice and incubated with LicoA (4, 20 and 40 μm). Peritoneal cells were obtained from EAE mice treated with LicoA (15 and 30 mg/kg/day. p.o.). H2 O2 , NO, IFN-γ, TNF-α and IL-17 production was determined in the presence or absence of concanavalin (ConA) or MOG35-55 stimulation.

KEY FINDINGS

LicoA (40 μm) inhibited H2 O2 , NO, IFN-γ, TNF-α and IL-17 production in splenocytes spontaneously or after both ConA and MOG35-55 stimulation. LicoA (30 mg/kg/day) reduced clinical score and severity of EAE mice, and inhibited TNF-α, IFN-γ and IL-17 production in peritoneal cells.

CONCLUSIONS

LicoA possesses immunomodulatory effects on H2 O2 , NO, IFN-γ, TNF-α and IL-17 production in cells from EAE mice. It is suggested that LicoA acts on the mechanism of development of EAE by IFN-γ, IL-17 and TNF-α inhibition, modulating the immune response on both Th1 and Th17 cells.