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2012 witnessed important developments for multiple sclerosis, including successful phase III trials of novel oral therapeutics and identification of the potassium channel KIR4.1 as an autoimmune target. Additionally, the lung was highlighted as an important site for immune-cell programming, and the relevance of a TNF receptor variant was clarified. [ABSTRACT FROM AUTHOR]

Background: Despite pleiotropic immunomodulatory effects of apolipoprotein E (apoE) in vitro, its effects on the clinical course of experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS) are still controversial. As sex hormones modify immunomodulatory apoE functions, they may explain contentious findings. This study aimed to investigate sex-specific effects of apoE on disease course of EAE and MS.Methods: MOG(35-55) induced EAE in female and male apoE-deficient mice was assessed clinically and histopathologically. apoE expression was investigated by qPCR. The association of the MS severity score (MSSS) and APOE rs429358 and rs7412 was assessed across 3237 MS patients using linear regression analyses.Results: EAE disease course was slightly attenuated in male apoE-deficient (apoE (-/-) ) mice compared to wildtype mice (cumulative median score: apoE (-/-)  = 2 [IQR 0.0-4.5]; wildtype = 4 [IQR 1.0-5.0]; n = 10 each group, p = 0.0002). In contrast, EAE was more severe in female apoE (-/-) mice compared to wildtype mice (cumulative median score: apoE (-/-)  = 3 [IQR 2.0-4.5]; wildtype = 3 [IQR 0.0-4.0]; n = 10, p = 0.003). In wildtype animals, apoE expression during the chronic EAE phase was increased in both females and males (in comparison to naïve animals; p < 0.001). However, in MS, we did not observe a significant association between MSSS and rs429358 or rs7412, neither in the overall analyses nor upon stratification for sex.Conclusions: apoE exerts moderate sex-specific effects on EAE severity. However, the results in the apoE knock-out model are not comparable to effects of polymorphic variants in the human APOE gene, thus pinpointing the challenge of translating findings from the EAE model to the human disease. [ABSTRACT FROM AUTHOR]

Escalation therapy with mitoxantrone (MX) in highly active multiple sclerosis is limited by partially dose-dependent side-effects. Predictors of therapeutic response may result in individualized risk stratification and MX dosing. ATP-binding cassette-transporters ABCB1 and ABCG2 represent multi-drug resistance mechanisms involved in active cellular MX efflux. Here, we investigated the role of ABC-gene single nucleotide polymorphisms (SNPs) for clinical MX response, corroborated by experimental in vitro and in vivo data. Frequencies of ABCB1 2677G>T, 3435C>T and five ABCG2-SNPs were analysed in 832 multiple sclerosis patients (Germany, Spain) and 264 healthy donors. Using a flow-cytometry-based in vitro assay, MX efflux in leukocytes from individuals with variant alleles in both ABC-genes (designated genotype ABCB1/ABCG2-L(ow), 22.2% of patients) was 37.7% lower than from individuals homozygous for common alleles (ABCB1/ABCG2-H(igh), P < 0.05, 14.8% of patients), resulting in genotype-dependent MX accumulation and cell death. Addition of glucocorticosteroids (GCs) inhibited MX efflux in vitro. ABC-transporters were highly expressed in leukocyte subsets, glial and neuronal cells as well as myocardium, i.e. cells/tissues potentially affected by MX therapy. In vivo significance was further corroborated in experimental autoimmune encephalomyelitis in Abcg2–/– animals. Using a MX dose titrated to be ineffective in wild-type animals, disease course and histopathology in Abcg2–/– mice were strongly ameliorated. Retrospective clinical analysis in MX monotherapy patients (n = 155) used expanded disability status scale, relapse rate and multiple sclerosis functional composite as major outcome parameters. The clinical response rate [overall 121 of 155 patients (78.1%)] increased significantly with genotypes associated with decreasing ABCB1/ABCG2-function [ABCB1/ABCG2-H 15/24 (62.5%) responders, ABCB1/ABCG2-I(ntermediate) 78/98 (79.6%), ABCB1/ABCG2-L 28/33 (84.8%), exact Cochran-Armitage test P = 0.039]. The odds ratio for response was 1.9 (95% CI 1.0–3.5) with each increase in ABCB1/ABCG2 score (from ABCB1/ABCG2-H to –I-, and –I to –L). In 36 patients with severe cardiac or haematological side effects no statistically relevant difference in genotype frequency was observed. However, one patient with biopsy proven cardiomyopathy only after 24 mg/m2 MX exhibited a rare genotype with variant, partly homozygous alleles in 3 ABC-transporter genes. In conclusion, SNPs in ABC-transporter genes may serve as pharmacogenetic markers associated with clinical response to MX therapy in multiple sclerosis. Combined MX/GC-treatment warrants further investigation. [ABSTRACT FROM PUBLISHER]

We are currently witnesses to and authors of a paradigm shift in neuropathology. While classical acute and chronic neuroinflammatory diseases such as meningitis or multiple sclerosis (MS) present aspects of neurodegeneration, the disease course of progressive degenerative disorders such as Alzheimer’s disease (AD), Parkinson’s disease (PD), or stroke-mediated neuronal deficit are demonstrably affected by inflammation. These insights have immediate consequences both for research methods and for the development of novel, more efficient therapies for these diseases. In this review, we analyze the inflammatory and degenerative pathological mechanisms in the brain with particular emphasis on the classical chronic inflammatory disease MS. We demonstrate that the latest pathological considerations not only require the application of advanced research technologies to investigate new pathomechanistic pathways, but also affect the investigation, development, and monitoring of novel potential therapeutic tools. [ABSTRACT FROM AUTHOR]

Deletion of T cells due to apoptosis induction is a regulatory mechanism in the human immune system that may be impaired in autoimmune diseases such as multiple sclerosis (MS). Involvement of the apoptosis-mediating CD95/CD95 ligand system in MS has been demonstrated. Here, we report that (auto)antigen-specific human T cells are not killed in vitro by soluble TNF-related apoptosis-inducing ligand (TRAIL) although expressing death-inducing receptors, TRAIL receptor 1 (TRAIL-R1) and TRAIL-R2. Apoptosis was assessed by caspase activation and DNA fragmentation, receptor expression was detected by RT-PCR and flow cytometry. The (auto)antigen-specific T cells were also resistant to specific TRAIL-R1/TRAIL-R2-directed induction of apoptosis, indicating that coexpression of the truncated TRAIL-R3 and TRAILR4 in these T cells is not responsible for the observed resistance. Upon stimulation, levels of death-inducing TRAIL receptors decreased whereas TRAIL was up-regulated on the cell surface. In contrast to CD95, the role of TRAIL receptors in MS might not involve regulation of T cell vulnerability. [ABSTRACT FROM AUTHOR]

Introduction Life on Earth developed in the presence and under the constant influence of gravity. Thus, it is a fundamental biological question, whether gravity is required for cellular functions at the molecular level in mammalian cells. Their special sensitivity to altered gravity renders cells of the immune system an ideal model system to understand if and how gravity on Earth is required for normal mammalian cell function and signal transduction. Methods Experiments have been performed using ground-based facilities such as fast-rotating 2D clinostat and hyper-g-centrifuges, and real microgravity provided by parabolic flights. For parabolic flight experiments on board the Airbus A300 ZERO-G, we developed RP (rapid prototyping)-based experimental equipment, which allows cell culture experiments with living mammalian cells in microgravity. We investigated the influence of altered gravity on T lymphocytes and on monocytic cells. Results In experiments with a fast rotating 2D clinostat, we detected strong and rapid initial changes of human T lymphocyte signal transduction within minutes of simulated weightlessness. However, most of the initial alterations returned to "normal" levels after 15 min-simulated weightlessness. Only the expression of p21 protein remained constantly elevated, compared to normogravity controls. In simulated weightlessness, human monocytic cells responded with tyrosine-phosphorylation of several proteins, whereas in PMA-stimulated monocytic cells, tyrosine-phosphorylation was nearly abrogated. Hypergravity of 1.8 g had no effects of the signal pathways investigated. In parabolic flight experiments, we found that 20 s microgravity resulted in distinct changes of expression of cell-cycle regulatory genes such as p21 and p27 on the transcriptional level in primary human T lymphocytes. In human monocytic cells, we detected a distinct downregulation of ICAM-1 (CD54) in non-stimulated and in PMAstimulated cells. Conclusion Thus we conclude that dysregulation of immune function in microgravity might be a consequence of 1) sustained induction of p21 as a cell cycle arrest signal in T lymphocytes and 2) Downregulation of ICAM-1 in monocytes/ macrophages, which are then no longer capable of interacting with T lymphocytes in the appropriate way. Since immune cells can respond and adapt to altered environmental conditions very effectively, it is indispendable to investigate whether the observed effects are still active after long-term exposure to altered gravity in the situation of adaptation and steady state. Thus, we are now the phase of preparation of two Space Experiments investigating the function of cells of the innate immunity, one scheduled for autumn 2009 on board of the International Space Station and one as a common Sino-German space life science mission scheduled for January 2010 on board of Shenzhou-8 Spacecraft. [ABSTRACT FROM AUTHOR]

Inflammatory reactions in the CNS, resulting from a loss of control and involving a network of non-neuronal and neuronal cells, are major contributors to the onset and progress of several major neurodegenerative diseases. Therapeutic strategies should therefore keep or restore the well-controlled and finely-tuned balance of immune reactions, and protect neurons from inflammatory damage. In our study, we selected plants of the Malaysian rain forest by an ethnobotanic approach, and investigated them in cell-based-assay-systems and in living brain tissue cultures in order to identify anti-inflammatory and neuroprotective effects. We found that extracts from the tropical plant Knema laurina (Black wild nutmeg) exhibited highly antiinflammatory and neuroprotective effects in cell culture experiments, reduced NO- and IL-6-release from activated microglia cells dose-dependently, and protects living brain tissue from microglia-mediated inflammatory damage. On the intracellular level, the extract inhibited ERK-1/2-phosphorylation, I-kappaB-phosphorylation and subsequently NF-kappaB-translocation in microglia cells. Knema laurina belongs to the family of Myristicaceae, which have been used for centuries for treatment of digestive and inflammatory diseases and is also a major food plant of the Giant Hornbill. Moreover, extract from Knema laurina promotes also neurogenesis in living brain tissue after oxygen-glucose deprivation. In conclusion, extract from Knema laurina not only controls and limits inflammatory reaction after primary neuronal damage, it promotes moreover neurogenesis if given hours until days after stroke-like injury in levels comparable to the best neurotrophic factors known today. [ABSTRACT FROM AUTHOR]

We have previously shown that the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (HMGCRI) atorvastatin is therapeutic in experimental autoimmune encephalomyelitis (EAE) while also inducing a sustained phosphorylation of the MAPK Erk1 that is important for inducing T cell anergy. However it is also known, that HMGCRI also influence the antigen presenting cell compartment including dendritic cells (DC). This led us to investigate the role of Erk1 in DC biology in more detail. Indeed bone-marrow derived dendritic cells from Erk1 deficient mice had an increased migratory capacity when compared with DC isolated from wildtype littermate mice. As a likely consequence to cytoskeletal regulation, Erk1-/- DC had an increased surface expression of costimulatory molecules and were more potent to prime T cells in vivo. To investigate the implications of these findings in an inflammatory scenario, we induced EAE (experimental autoimmune encephalomyelitis) in Erk1-/- and Erk1+/+ mice with myelin oligodendrocyte glycoprotein peptide 35-55 (MOG35-55) and could show that a deficiency of this MAPK results in a moderate increase in disease severity. To differentiate the role of Erk1 between peripheral immune system and the brain compartment we induced EAE in Erk1+/+ mice harboring Erk1-/- immune cells by applying bone marrow chimeras (Erk1-/- --> Erk1+/+). We report that Erk1 has an important regulatory function in the immune system as shown by pronounced disease severity in Erk1-/- --> Erk1+/+ bone marrow chimeras. All together these results indicate the significance of Erk1 in regulating DC functions that are relevant for T cell priming and neuroinflammation, and thus signal the importance of therapeutically targeting this MAPK for the treatment of autoimmune diseases. [ABSTRACT FROM AUTHOR]