Micro RNA-155 participates in re-activation of encephalitogenic T cells

MicroRNAs (miR) are small non-coding RNAs involved in the immune response regulation. miR-155 has been attributed a major pro-inflammatory role in the pathogenesis of multiple sclerosis and its animal model experimental autoimmune encephalomyelitis (EAE). Here, a role of miR-155 in re-activation of encephalitogenic CD4(+) T cells was investigated. Dark Agouti rats were immunized with myelin basic protein (MBP) emulsified in complete Freund's adjuvant. CD4(+) T cells were purified from draining lymph node cells (DLNC) obtained in the inductive phase and from spinal cord immune cells (SCIC) isolated at the peak of EAE. CD4(+) T cells obtained from SCIC (i.e., in vivo re-activated cells) had markedly higher expression of miR-155 in comparison to those purified from DLNC (not re-activated). Likewise, in vitro re-activation of DLNC with MBP led to increase in miR-155 expression. Further, DLNC and DLNC CD4(+) T cells were transfected with an inhibitor of miR-155 during in vitro re-activation. As a result, expression of important CD4(+) T cell effector cytokines IFN-gamma and IL-17, but not of regulatory cytokines IL-10 and TGF-beta, was reduced. These results imply that miR-155 supports re-activation of encephalitogenic CD4+ T cells. Our results contribute to a view that miR-155 might be a valuable target in multiple sclerosis therapy. (C) 2015 Elsevier Masson SAS. All rights reserved.Ministry of Education, Science and Technological Development of the Republic of Serbia {[}173035, 175038, 173013

A Comparative Analysis of Multiple Sclerosis-Relevant Anti-Inflammatory Properties of Ethyl Pyruvate and Dimethyl Fumarate

Dimethyl fumarate (DMF), a new drug for multiple sclerosis (MS) treatment, acts against neuroinflammation via mechanisms that are triggered by adduct formation with thiol redox switches. Ethyl pyruvate (EP), an off-the-shelf agent, appears to be a redox analog of DMF, but its immunomodulatory properties have not been put into the context of MS therapy. In this article, we examined and compared the effects of EP and DMF on MS-relevant activity/functions of T cells, macrophages, microglia, and astrocytes. EP efficiently suppressed the release of MS signature cytokines, IFN-gamma and IL-17, from human PBMCs. Furthermore, the production of these cytokines was notably decreased in encephalitogenic T cells after in vivo application of EP to rats. Production of two other proinflammatory cytokines, IL-6 and TNF, and NO was suppressed by EP in macrophages and microglia. Reactive oxygen species production in macrophages, microglia activation, and the development of Ag-presenting phenotype in microglia and macrophages were constrained by EP. The release of IL-6 was reduced in astrocytes. Finally, EP inhibited the activation of transcription factor NF-kappa B in microglia and astrocytes. Most of these effects were also found for DMF, implying that EP and DMF share common targets and mechanisms of action. Importantly, EP had in vivo impact on experimental autoimmune encephalomyelitis, an animal model of MS. Treatment with EP resulted in delay and shortening of the first relapse, and lower clinical scores, whereas the second attack was annihilated. Further studies on the possibility to use EP as an MS therapeutic are warranted.Ministry of Education, Science and Technological Development of the Republic of Serbia {[}OI173035, OI175038, OI173014, OI173013

Trichinella spiralis shares epitopes with human autoantigens

Like other helminths, Trichinella spiralis has evolved strategies to allow it to survive in the host organism, including the expression of epitopes similar to those present in either expressed or hidden host antigens. To identify T. spiralis-derived antigens that are evolutionarily conserved in the parasite and its host and that could be responsible for its evasion of the host immune response, we examined the reactivity of six different types of autoantibodies to T. spiralis larvae from muscle. T. spiralis antigens that share epitopes with human autoantigens were identified by assessing the cross-reactivity of autoantibody-containing serum samples with T. spiralis antigens in the absence of specific anti-parasite antibodies. Of the 55 autoantibody-containing human serum samples that we analysed by immunohistological screening, 24 (43.6%) recognised T. spiralis muscle larvae structures such as the subcuticular region, the genital primordium or the midgut. Using Western blots, we demonstrated that the same sera reacted with 24 protein components of T. spiralis muscle larvae excretory-secretory L1 antigens. We found that the human autoantibodies predominantly bound antigens belonging to the TSL1 group; more specifically, the autoantibody-containing sera reacted most frequently with the 53-kDa component. Thus, this protein is a good candidate for further studies of the mechanisms of T. spiralis-mediated immunomodulation

Tumor necrosis factor stimulates expression of CXCL12 in astrocytes

It has been increasingly appreciated that tumor necrosis factor (TNF) performs various protective and anti-inflammatory functions in multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). Recently, CXCL12 has been identified as a key inhibitor of leukocyte entry into the central nervous system (CNS) and as a regulator of inflammation resulting from the invasion. Here, a positive correlation between expression of TNF and CXCL12 in the CNS samples of EAE rats is presented. Also, it is shown that TNF potentiates CXCL12 expression in astrocytes. These results contribute to a view that TNF produced within the CNS plays a protective role in neuroinflammation. (C) 2015 Elsevier GmbH. All rights reserved.Ministry of Education, Science and Technological Development of the Republic of Serbia {[}173035, 175038, 173013

Cerebrospinal fluid and serum uric acid levels in patients with multiple sclerosis

Background: Peroxynitrite was hypothesized to be involved in the pathogenesis of multiple sclerosis (MS) through its various neurotoxic effects. Uric acid (UA) was shown to be a strong peroxynitrite scavenger. Methods: We analyzed cerebrospinal fluid (CSF) and serum UA concentrations in 30 MS patients and 20 controls with non-inflammatory neurological diseases (NIND) and correlated these findings with demographic and clinical characteristics of MS patients. Disease activity was assessed by brain magnetic resonance imaging (MRI) and the CSF/serum albumin quotient as an indicator of the state of blood-brain-barrier (BBB). Results: Serum UA concentrations were found to be significantly lower in MS patients compared with controls (p=0.019). CSF UA concentrations were lower in MS patients as compared to controls, as well as in patients with active MS (clinical and/or MRI activity) in comparison to patients with inactive MS or controls, but these differences were not statistically significant. Significant correlation was found between CSF and serum UA concentrations (p=0.016) in MS patients, but not in controls; and between CSF UA concentrations and the CSF/serum albumin quotient in MS patients (p=0.043), but not in controls. Conclusions: Our results support the significance of UA in the pathogenesis of MS. Decreased serum UA concentrations in MS patients might be due to both intrinsically reduced antioxidant capacity and increased UA consumption in MS. CSF UA concentrations may not be a reliable marker of disease activity in MS since its concentration is dependent on leakage of UA molecules from serum through the damaged BBB and the balance between consumption/production within the central nervous system (CNS). Clin Chem Lab Med 2009;47:848–53.Peer Reviewe

Correlation of gut microbiota composition with resistance to experimental autoimmune encephalomyelitis in rats

Multiple sclerosis is a chronic inflammatory disease of the central nervous system (CNS). It is widely accepted that autoimmune response against the antigens of the CNS is the essential pathogenic force in the disease. It has recently become increasingly appreciated that activated encephalitogenic cells tend to migrate towards gut associated lymphoid tissues (GALT) and that interrupted balance between regulatory and inflammatory immunity within the GALT might have decisive role in the initiation and propagation of the CNS autoimmunity. Gut microbiota composition and function has the major impact on the balance in the GALT. Thus, our aim was to perform analyses of gut microbiota in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Albino Oxford (AO) rats that are highly resistant to EAE induction and Dark Agouti (DA) rats that develop EAE after mild immunization were compared for gut microbiota composition in different phases after EAE induction. Microbial analyses of the genus Lactobacillus and related lactic acid bacteria showed higher diversity of Lactobacillus spp. in EAE-resistant AO rats, while some members of Firmicutes and Proteobacteria (Undibacterium oligocarboniphilum) were detected only in faeces of DA rats at the peak of the disease (between 13 and 16 days after induction). Interestingly, Turicibacter sp. that was found exclusively in non-immunized AO, but not in DA rats in our previous study was detected in DA rats that remained healthy 16 days after induction. Similar observation was obtained for the members of Lachnospiraceae. As dominant presence of the members of Lachnospiraceae family in gut microbial community has been linked with mild symptoms of various diseases, it is tempting to assume that Turicibacter sp. and Lachnospiraceae contribute to the prevention of EAE development and the alleviation of the disease symptoms. Further, production of a typical regulatory cytokine interleukin-10 was compared in GALT cells of AO and DA rats, and higher production was observed in DA rats. Our data contribute to the idea that gut microbiota and GALT considerably influence multiple sclerosis pathogenesis