DC specific Smad7 deficiency promotes differentiation of tolerogenic DCs able to attenuate EAE

DC specific Smad7 deficiency promotes differentiation of tolerogenic DCs able to attenuate EAE

Abstracts orthologue, Ema, may be involved in endosomal maturation. Thus, we have co-transfected Jurkat T- and Raji B-cells with an early endosomal m...

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Abstracts

orthologue, Ema, may be involved in endosomal maturation. Thus, we have co-transfected Jurkat T- and Raji B-cells with an early endosomal marker followed by analysis with image-based flow cytometry to reveal whether different levels of CLEC16A expression have an effect on endosomal size and distribution. Our studies may give clues to how CLEC16A contributes in the development of autoimmune diseases.

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390 DC specific Smad7 deficiency promotes differentiation of tolerogenic DCs able to attenuate EAE Dominika Lukasa, Nir Yogeva, Junda M. Kelb, Lara Jungmannc, Marco Prinzc, Ingo Kleiterd, Björn E. Clausena, Ari Waismana

doi:10.1016/j.jneuroim.2014.08.175 a

381 ‘Superior’ dominant peptide itself shut down the reactivation of an animal model of multiple sclerosis through later activation of antigen-specific regulatory cells: Application for inverse vaccine Youwei Lin Department of Immunology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan The immune network is a complex system for host defenses comprising various types of inflammatory and regulatory cells. Autoimmune diseases occur because of dysregulation in homeostasis caused by imbalance of these cells. The pattern of imbalance depends on the disease. Most autoimmune diseases are chronic, and the mechanism underlying this chronic nature is yet to be determined. Monoclonal antibody therapy is highly specific to the molecules targeted and is therefore highly effective. However, this therapy cannot be applied to all autoimmune diseases, and even the most effective therapy is incapable of completely inhibiting disease activity. Antigen-specific therapies have the ability to inhibit disease activity; however, their application is limited because of the presence of various disease-specific antigens. Regulatory cell therapies also have potential, but pose a plasticity problem. By focusing our research on experimental autoimmune encephalomyelitis (EAE), which is a multiple sclerosis (MS) model and normally initially has a relapse or remission course, followed by a progressive course, we can develop alternative therapies for the treatment of autoimmune diseases by exploring the mechanism of relapse and remission. From the phenomena that immunizing peptide itself determines the difference between monophasic-EAE and relapsingEAE, we found out that two-correlated non-genetic factors can shut down the reactivation in the EAE. One is kinetics and the component of CD4+CD25+ regulatory T cells (Treg), which are characterized by their later expansion after emerging of encephalitogenic T cells and by their subset expressing both CD69 and CD103 (=DP-Treg). DP-Treg is the most efficacious subset showing the highest Treg-compatible signatures with high antigen-specificity exerting stability due to downregulation of IL-6R expression, nevertheless with activated effector phenotype. The other is a hierarchy of encephalitogenic peptide itself to be immunized, which means that the more dominant peptide can develop acute EAE, the less relapse and re-induction of EAE occurs. This superiority of dominant peptide is characterized by specificity to itself, that is, it can suppress response to other peptides broadly and establish permanent remission. Peptide tolerance induced orally or intravenously could not get such wide suppression. Taken together, efficient induction of DP-Treg is correlated with superiority of self-peptide itself, suggesting ‘immunological homunculus’. This can be applied for treatment such as tissue-specific inverse vaccination for autoimmune diseases. doi:10.1016/j.jneuroim.2014.08.176

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg University, Mainz, Germany; bDepartment of Immunology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; cDepartment of Neuropathology & Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany; d Department of Neurology, St. Josef- Hospital, Ruhr- University Bochum, Bochum, Germany Dendritic cells (DCs) as professional antigen presenting cells, play a vital role in the pathogenesis of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). DCs secrete and respond to the anti-inflammatory cytokine transforming growth factor (TGF)-b. Smad7 is expressed upon TGF-b signaling and negatively regulates it. However, in addition to TGF-b, other stimuli (i.e. IFN-g) can also induce Smad7 expression. To understand the role of Smad7 in DCs in vivo we used a DC specific Smad7 knockout mouse model. Analysis of naive mice lacking Smad7 specifically in DCs revealed no significant difference in the frequencies or total cell counts of splenic or lymph node DCs as characterized as CD11c MHC-II positive cells, but displayed a shift in DC subsets towards the CD8 CD103 positive DCs, a subset associated with T regulatory cell (Treg) induction. The frequencies and total cell counts of T cells and especially Tregs in naive mice lacking Smad7 in DCs were comparable to controls. However, upon MOGp35-55 immunization, mice devoid of Smad7 in DCs showed significantly attenuated disease progression with significantly reduced CNS infiltration of MOGp35-55 reactive T effector cells. Following immunization of these mice, we detected a significant increase of peripheral as well as CNS-infiltrating Tregs in mice with DC-specific Smad7 deletion as compared to control animals. Depletion of Tregs restored EAE susceptibility in these mice. Taken together, our results indicate an important function for Smad7 in DC mediated tolerance during autoimmune disease. doi:10.1016/j.jneuroim.2014.08.177

104 Integrative analysis of DNA methylation and gene expression identifies distinct profiles among immune cells subsets Shimrat Mamruta, Nili Avidana, Elsebeth Staun-rama, Elizabeta Ginzburga, Frédérique Truffaultb, Mélinée Frenkianb, Sonia Berrih-akninb, Ariel Millera,c a

Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, University, Haifa, Israel; bResearch Unit (INSERM U974/CNRS UMR7215/ UPMC UM76/AIM), Institute of Myology Pitié-Salpêtrière, University, Paris, France; cDivision of Neuroimmunology and Multiple Sclerosis Center, Carmel Medical Center, Hospital, Haifa, Israel DNA methylation is one of the epigenetic mechanisms underlying links between genetics and environment. Increased DNA methylation is mainly associated with decreased gene expression; however accumulating data suggests that this relationship is more complex.