Characterization of immune cell subsets during the active phase of multiple sclerosis reveals disease and c-Jun N-terminal kinase pathway biomarkers

BackgroundAutoimmune activation and deregulated apoptosis of T lymphocytes are involved in multiple sclerosis (MS). c-Jun N-terminal kinase (JNK) plays a role in T-cell survival and apoptosis.ObjectivesThe aim of this work was to investigate the role of the JNK-dependent apoptosis pathway in relapsing-remitting MS (RRMS).MethodsThe immunomodulatory effect of AS602801, a JNK inhibitor, was firstly evaluated on activated peripheral blood mononuclear cells (PBMCs) from healthy volunteers (HVs) and secondly in unstimulated purified CD4+, CD8+ and CD11b+ cells from RRMS patients and HVs. Moreover JNK/inflammation/apoptosis related genes were investigated in RRMS and HV samples.ResultsIn activated PBMCs from HVs, we showed that AS602801 blocked T-lymphocyte proliferation and induced apoptosis. In RRMS CD4+ and CD8+ cells, AS602801 induced apoptosis genes and expression of surface markers, while in RRMS CD11b+ cells it induced expression of innate immunity receptors and co-stimulatory molecules. Untreated cells from RRMS active-phase patients significantly released interleukin-23 (IL-23) and interferon-gamma (IFN-γ) and expressed less apoptosis markers compared to the cells of HVs. Moreover, gene expression was significantly different in cells from RRMS active-phase patients vs. HVs. By comparing RRMS PBMCs in the active and stable phases, a specific genomic signature for RRMS was indentified. Additionally, CASP8AP2, CD36, ITGAL, NUMB, OLR1, PIAS-1, RNASEL, RTN4RL2 and THBS1 were identified for the first time as being associated to the active phase of RRMS.ConclusionsThe analysis of the JNK-dependent apoptosis pathway can provide biomarkers for activated lymphocytes in the active phase of RRMS and a gene expression signature for disease status. The reported results might be useful to stratify patients, thereby supporting the development of novel therapies.Chiara Ferrandi, Fabien Richard, Patrizia Tavano, Ehud Hauben, Valerie Barbie, Jean-Pierre Gotteland, Beatrice Greco, Mara Fortunato, Maurizio F Mariani, Roberto Furlan, Giancarlo Comi, Gianvito Martino and Paola F Zarati

InlA Promotes Dissemination of <em>Listeria monocytogenes</em> to the Mesenteric Lymph Nodes during Food Borne Infection of Mice

<div><p>Intestinal <em>Listeria monocytogenes</em> infection is not efficient in mice and this has been attributed to a low affinity interaction between the bacterial surface protein InlA and E-cadherin on murine intestinal epithelial cells. Previous studies using either transgenic mice expressing human E-cadherin or mouse-adapted <em>L. monocytogenes</em> expressing a modified InlA protein (InlA^m) with high affinity for murine E-cadherin showed increased efficiency of intragastric infection. However, the large inocula used in these studies disseminated to the spleen and liver rapidly, resulting in a lethal systemic infection that made it difficult to define the natural course of intestinal infection. We describe here a novel mouse model of oral listeriosis that closely mimics all phases of human disease: (1) ingestion of contaminated food, (2) a distinct period of time during which <em>L. monocytogenes</em> colonize only the intestines, (3) varying degrees of systemic spread in susceptible vs. resistant mice, and (4) late stage spread to the brain. Using this natural feeding model, we showed that the type of food, the time of day when feeding occurred, and mouse gender each affected susceptibility to <em>L. monocytogenes</em> infection. Co-infection studies using <em>L. monocytogenes</em> strains that expressed either a high affinity ligand for E-cadherin (InlA^m), a low affinity ligand (wild type InlA from <em>Lm</em> EGDe), or no InlA (Δ<em>inlA</em>) showed that InlA was not required to establish intestinal infection in mice. However, expression of InlA^m significantly increased bacterial persistence in the underlying lamina propria and greatly enhanced dissemination to the mesenteric lymph nodes. Thus, these studies revealed a previously uncharacterized role for InlA in facilitating systemic spread via the lymphatic system after invasion of the gut mucosa.</p> </div