Refine
Has Fulltext
- yes (21)
Is part of the Bibliography
- yes (21)
Year of publication
Document Type
- Journal article (19)
- Report (2)
Language
- English (21)
Keywords
- multiple sclerosis (4)
- inflammation (3)
- Medizin (2)
- NEUROWIND (2)
- blood-brain barrier (2)
- experimental autoimmune encephalomyelitis (2)
- neurology (2)
- B cells (1)
- C1-inhibitor (1)
- EAE (1)
Institute
- Neurologische Klinik und Poliklinik (19)
- Neurochirurgische Klinik und Poliklinik (2)
- Rudolf-Virchow-Zentrum (2)
- Deutsches Zentrum für Herzinsuffizienz (DZHI) (1)
- Institut für Anatomie und Zellbiologie (1)
- Institut für Klinische Epidemiologie und Biometrie (1)
- Klinik und Poliklinik für Dermatologie, Venerologie und Allergologie (1)
- Medizinische Klinik und Poliklinik II (1)
EU-Project number / Contract (GA) number
- 026155 (1)
From October 30–November 1, 2015, the 7th NEUROWIND e.V. meeting was held in Motzen, Brandenburg, Germany. Seventy doctoral students and postdocs from over 25 different groups working in German and Swiss University Hospitals or Research Institutes attended the meeting to discuss their latest experiments and findings in the fields of neuroimmunology, neurodegeneration and neurovascular research. This meeting report summarizes the many diverse presentations and the new preclinical to clinical neurology research data that were shared by the participants at the meeting.
Migration of immune cells to the target organ plays a key role in autoimmune disorders like multiple sclerosis (MS). However, the exact underlying mechanisms of this active process during autoimmune lesion pathogenesis remain elusive. To test if pro-inflammatory and regulatory T cells migrate via a similar molecular mechanism, we analyzed the expression of different adhesion molecules, as well as the composition of infiltrating T cells in an in vivo model of MS, adoptive transfer experimental autoimmune encephalomyelitis in rats. We found that the upregulation of ICAM-I and VCAM-I parallels the development of clinical disease onset, but persists on elevated levels also in the phase of clinical remission. However, the composition of infiltrating T cells found in the developing versus resolving lesion phase changed over time, containing increased numbers of regulatory T cells (FoxP3) only in the phase of clinical remission. In order to test the relevance of the expression of cell adhesion molecules, animals were treated with purified antibodies to ICAM-I and VCAM-I either in the phase of active disease or in early remission. Treatment with a blocking ICAM-I antibody in the phase of disease progression led to a milder disease course. However, administration during early clinical remission aggravates clinical symptoms. Treatment with anti-VCAM-I at different timepoints had no significant effect on the disease course. In summary, our results indicate that adhesion molecules are not only important for capture and migration of pro-inflammatory T cells into the central nervous system, but also permit access of anti-inflammatory cells, such as regulatory T cells. Therefore it is likely to assume that intervention at the blood brain barrier is time dependent and could result in different therapeutic outcomes depending on the phase of CNS lesion development.
Ischemic stroke is the second leading cause of death worldwide. Only one moderately effective therapy exists, albeit with contraindications that exclude 90% of the patients. This medical need contrasts with a high failure rate of more than 1,000 pre-clinical drug candidates for stroke therapies. Thus, there is a need for translatable mechanisms of neuroprotection and more rigid thresholds of relevance in pre-clinical stroke models. One such candidate mechanism is oxidative stress. However, antioxidant approaches have failed in clinical trials, and the significant sources of oxidative stress in stroke are unknown. We here identify NADPH oxidase type 4 (NOX4) as a major source of oxidative stress and an effective therapeutic target in acute stroke. Upon ischemia, NOX4 was induced in human and mouse brain. Mice deficient in NOX4 (Nox42/2) of either sex, but not those deficient for NOX1 or NOX2, were largely protected from oxidative stress, blood-brain-barrier leakage, and neuronal apoptosis, after both transient and permanent cerebral ischemia. This effect was independent of age, as elderly mice were equally protected. Restoration of oxidative stress reversed the stroke-protective phenotype in Nox42/2 mice. Application of the only validated low-molecular-weight pharmacological NADPH oxidase inhibitor, VAS2870, several hours after ischemia was as protective as deleting NOX4. The extent of neuroprotection was exceptional, resulting in significantly improved long-term neurological functions and reduced mortality. NOX4 therefore represents a major source of oxidative stress and novel class of drug target for stroke therapy.
Traumatic brain injury (TBI) induces a strong inflammatory response which includes blood-brain barrier damage, edema formation and infiltration of different immune cell subsets. More recently, microvascular thrombosis has been identified as another pathophysiological feature of TBI. The contact-kinin system represents an interface between inflammatory and thrombotic circuits and is activated in different neurological diseases. C1-Inhibitor counteracts activation of the contact-kinin system at multiple levels. We investigated the therapeutic potential of C1-Inhibitor in a model of TBI. Male and female C57BL/6 mice were subjected to cortical cryolesion and treated with C1-Inhibitor after 1 h. Lesion volumes were assessed between day 1 and day 5 and blood-brain barrier damage, thrombus formation as well as the local inflammatory response were determined post TBI. Treatment of male mice with 15.0 IU C1-Inhibitor, but not 7.5 IU, 1 h after cryolesion reduced lesion volumes by ~75% on day 1. This protective effect was preserved in female mice and at later stages of trauma. Mechanistically, C1-Inhibitor stabilized the blood-brain barrier and decreased the invasion of immune cells into the brain parenchyma. Moreover, C1-Inhibitor had strong antithrombotic effects. C1-Inhibitor represents a multifaceted anti-inflammatory and antithrombotic compound that prevents traumatic neurodegeneration in clinically meaningful settings.
From October 31th – November 2nd, 2014, the 6th NEUROWIND e.V. meeting was held in Motzen, Brandenburg, Germany. 70 doctoral students and postdocs from over 25 different groups working in German and Swiss university hospitals or research institutes attended the meeting to discuss their latest experiments and findings in the fields of neuroimmunology, neurodegeneration and neurovascular research. The meeting was regarded as a very well organized platform to support research of young investigators in Germany and all participants enjoyed the stimulating environment for lively in depth discussions.
According to the major aim of NEUROWIND e.V. to support younger researchers in Germany the 4th NEUROWIND YOUNG SCIENTIST AWARD for experimental neurology was awarded to Michael Breckwoldt on his work in the group of Thomas Misgeld (Institute of Neuronal Cell Biology, Technische Universität München, Germany). The successful project was published in Nature Medicine entitled “Multiparametric optical analysis of mitochondrial redox signals during neuronal physiology and pathology in vivo”. This outstanding paper deals with a molecular imaging approach in living mice to optically analyze the role of mitochondrial redox signals in axons in health and disease. The award is endowed with 20.000 Euro sponsored by Merck Serono GmbH, Darmstadt, Germany (unrestricted educational grant).
This year’s keynote lecture was given by Bernhard Hemmer, Head of the Department of Neurology at the Klinikum rechts der Isar, Technische Universität München. Dr. Hemmer highlighted the particular role of B cells and (auto)antibodies in multiple sclerosis (MS). As a new highlight Dr. Urbahns, head of global discovery technologies at Merck research laboratories, gave insights from research practice in the pharmaceutical industry and introduced a shift in the view on present-day drug discovery paradigms.
The two bradykinin receptors B1R and B2R are central components of the kallikrein–kinin system with different expression kinetics and binding characteristics. Activation of these receptors by kinins triggers inflammatory responses in the target organ and in most situations enhances tissue damage. We could recently show that blocking of B1R, but not B2R, protects from cortical cryolesion by reducing inflammation and edema formation. In the present study, we investigated the role of B1R and B2R in a closed head model of focal traumatic brain injury (TBI; weight drop). Increased expression of B1R in the injured hemispheres of wild-type mice was restricted to the later stages after brain trauma, i.e. day 7 (P<0.05), whereas no significant induction could be observed for the B2R (P>0.05). Mice lacking the B1R, but not the B2R, showed less functional deficits on day 3 (P<0.001) and day 7 (P<0.001) compared with controls. Pharmacological blocking of B1R in wild-type mice had similar effects. Reduced axonal injury and astroglia activation could be identified as underlying mechanisms, while inhibition of B1R had only little influence on the local inflammatory response in this model. Inhibition of B1R may become a novel strategy to counteract trauma-induced neurodegeneration.
NKG2D is an activating receptor on T cells, which has been implicated in the pathogenesis of autoimmune diseases. T cells are critically involved in idiopathic inflammatory myopathies (IIM) and have been proposed as specific therapeutic targets. However, the mechanisms underlying T cell-mediated progressive muscle destruction in IIM remain to be elucidated. We here determined the involvement of the NKG2D - IL-15 signaling pathway. Primary human myoblasts expressed NKG2D ligands, which were further upregulated upon inflammatory stimuli. In parallel, shedding of the soluble NKG2D ligand MICA (sMICA) decreased upon inflammation potentially diminishing inhibition of NKG2D signaling. Membrane-related expression of IL-15 by myoblasts induced differentiation of naive CD8\(^+\) T cells into highly activated, cytotoxic \(CD8^+NKG2D^{high}\) T cells demonstrating NKG2D-dependent lysis of myoblasts in vitro. \(CD8^+NKG2D^{high}\) T cell frequencies were increased in the peripheral blood of polymyositis (PM) patients and correlated with serum creatinine kinase concentrations, while serum sMICA levels were not significantly changed. In muscle biopsy specimens from PM patients expression of the NKG2D ligand MICA/B was upregulated, IL-15 was expressed by muscle cells, CD68\(^+\) macrophages as well as CD4\(^+\) T cells, and \(CD8^+NKG2D^+\) cells were frequently detected within inflammatory infiltrates arguing for a local signaling circuit in the inflammatory muscle milieu. In conclusion, the NKG2D - IL-15 signaling pathway contributes to progressive muscle destruction in IIM potentially opening new therapeutic avenues.
Background
Brain ischemia is known to include neuronal cell death and persisting neurological deficits. A lack of oxygen and glucose are considered to be key mediators of ischemic neurodegeneration while the exact mechanisms are yet unclear. In former studies the expression of two different two-pore domain potassium \((K_{2P})\) channels (TASK1, TREK1) were shown to ameliorate neuronal damage due to cerebral ischemia. In neurons, TASK channels carrying hyperpolarizing \(K^+\) leak currents, and the pacemaker channel HCN2, carrying depolarizing \(I_h\), stabilize the membrane potential by a mutual functional interaction. It is assumed that this ionic interplay between TASK and HCN2 channels enhances the resistance of neurons to insults accompanied by extracellular pH shifts.
Methods
In C57Bl/6 (wildtype, WT), \(hcn2^{+/+}\) and \(hcn2^{-/-}\) mice we used an in vivo model of cerebral ischemia (transient middle cerebral artery occlusion (tMCAO)) to depict a functional impact of HCN2 in stroke formation. Subsequent analyses comprise behavioural tests and hcn2 gene expression assays.
Results
After 60 min of tMCAO induction in WT mice, we collected tissue samples at 6, 12, and 24 h after reperfusion. In the infarcted neocortex, hcn2 expression analyses revealed a nominal peak of hcn2 expression 6 h after reperfusion with a tendency towards lower expression levels with longer reperfusion times. Hcn2 gene expression levels in infarcted basal ganglia did not change after 6 h and 12 h. Only at 24 h after reperfusion, hcn2 expression significantly decreases by ~55%. However, 30 min of tMCAO in hcn2-/- as well as hcn2+/+ littermates induced similar infarct volumes. Behavioural tests for global neurological function (Bederson score) and motor function/coordination (grip test) were performed at day 1 after surgery. Again, we found no differences between the groups.
Conclusions
Here, we hypothesized that the absence of HCN2, an important functional counter player of TASK channels, affects neuronal survival during stroke-induced tissue damage. However, together with a former study on TASK3 these results implicate that both TASK3 and HCN2 which were supposed to be neuroprotective due to their pH-dependency, do not influence ischemic neurodegeneration during stroke in the tMCAO model.
From october 25th - 27th 2013, the 5th NEUROWIND e.V. meeting was held in Motzen, Brandenburg, Germany. This year more than 60 doctoral students and postdocs from over 25 different groups working in German university hospitals or research institutes attended the meeting to discuss their latest findings in the fields of neuroimmunology, neurodegeneration and neurovascular research. All participants appreciated the stimulating environment in Motzen, Brandenburg, and people took the opportunity for scientific exchange, discussion about ongoing projects and already started further collaborations. Like in the previous years, the symposium was regarded as a very well organized platform to support research of young investigators in Germany.
According to the major aim of NEUROWIND e.V. to support younger researchers in Germany the 3rd NEUROWIND YOUNG SCIENTIST AWARD for experimental neurology was awarded to Ruth Stassart working in the group of Klaus Armin Nave and Wolfgang Brück (MPI Göttingen and Department of Neuropathology, Göttingen Germany). The successful work was published in Nature Neuroscience entitled “A role for Swann cell-derived neuregulin-1 in remyelination”. This outstanding paper deals with the function of Schwann cell neuregulin as an endogenous factor for myelin repair. The award is endowed with 20.000 Euro sponsored by Merck Serono GmbH, Darmstadt, Germany (unrestricted educational grant). This year’s keynote lecture was given by Albert Ludolph, Head of the Department of Neurology at the University Clinic of Ulm. Dr. Ludolph highlighted the particular role of individual scientists for the development of research concepts in Alzheimer´s disease (AD) and frontotemporal dementia (FTD).