TY  - JOUR
AB  - Ferroptosis is a form of lipid peroxidation-mediated cell death and damage triggered by excess iron and insufficiency in the glutathione antioxidant pathway. Oxidative stress is thought to play a crucial role in progressive forms of multiple sclerosis (MS) in which iron deposition occurs. In this study we assessed if ferroptosis plays a role in a chronic form of experimental autoimmune encephalomyelitis (CH-EAE), a mouse model used to study MS. Changes were detected in the mRNA levels of several ferroptosis genes in CH-EAE but not in relapsing-remitting EAE. At the protein level, expression of iron importers is increased in the earlier stages of CH-EAE (onset and peak). While expression of hemoxygenase-1, which mobilizes iron from heme, likely from phagocytosed material, is increased in macrophages at the peak and progressive stages. Excess iron in cells is stored safely in ferritin, which increases with disease progression. Harmful, redox active iron is released from ferritin when shuttled to autophagosomes by 'nuclear receptor coactivator 4' (NCOA4). NCOA4 expression increases at the peak and progressive stages of CH-EAE and accompanied by increase in redox active ferrous iron. These changes occur in parallel with reduction in the antioxidant pathway (system xCT, glutathione peroxidase 4 and glutathione), and accompanied by increased lipid peroxidation. Mice treated with a ferroptosis inhibitor for 2 weeks starting at the peak of CH-EAE paralysis, show significant improvements in function and pathology. Autopsy samples of tissue sections of secondary progressive MS (SPMS) showed NCOA4 expression in macrophages and oligodendrocytes along the rim of mixed active/inactive lesions, where ferritin+ and iron containing cells are located. Cells expressing NCOA4 express less ferritin, suggesting ferritin degradation and release of redox active iron, as indicated by increased lipid peroxidation. These data suggest that ferroptosis is likely to contribute to pathogenesis in CH-EAE and SPMS.
AU  - Jhelum, P.*
AU  - Zandee, S.*
AU  - Ryan, F.*
AU  - Zarruk, J.G.*
AU  - Michalke, B.
AU  - Venkataramani, V.*
AU  - Curran, L.*
AU  - Klement, W.*
AU  - Prat, A.*
AU  - David, S.*
C1  - 68070
C2  - 54548
CY  - Campus, 4 Crinan St, London N1 9xw, England
TI  - Ferroptosis induces detrimental effects in chronic EAE and its implications for progressive MS.
JO  - Acta Neuropathol. Commun.
VL  - 11
IS  - 1
PB  - Bmc
PY  - 2023
ER  - 

TY  - JOUR
AB  - Cytoplasmic aggregation and concomitant nuclear clearance of the RNA-binding protein TDP-43 are found in ~ 90% of cases of amyotrophic lateral sclerosis and ~ 45% of patients living with frontotemporal lobar degeneration, but no disease-modifying therapy is available. Antibody therapy targeting other aggregating proteins associated with neurodegenerative disorders has shown beneficial effects in animal models and clinical trials. The most effective epitopes for safe antibody therapy targeting TDP-43 are unknown. Here, we identified safe and effective epitopes in TDP-43 for active and potential future passive immunotherapy. We prescreened 15 peptide antigens covering all regions of TDP-43 to identify the most immunogenic epitopes and to raise novel monoclonal antibodies in wild-type mice. Most peptides induced a considerable antibody response and no antigen triggered obvious side effects. Thus, we immunized mice with rapidly progressing TDP-43 proteinopathy ("rNLS8" model) with the nine most immunogenic peptides in five pools prior to TDP-43ΔNLS transgene induction. Strikingly, combined administration of two N-terminal peptides induced genetic background-specific sudden lethality in several mice and was therefore discontinued. Despite a strong antibody response, no TDP-43 peptide prevented the rapid body weight loss or reduced phospho-TDP-43 levels as well as the profound astrogliosis and microgliosis in rNLS8 mice. However, immunization with a C-terminal peptide containing the disease-associated phospho-serines 409/410 significantly lowered serum neurofilament light chain levels, indicative of reduced neuroaxonal damage. Transcriptomic profiling showed a pronounced neuroinflammatory signature (IL-1β, TNF-α, NfκB) in rNLS8 mice and suggested modest benefits of immunization targeting the glycine-rich region. Several novel monoclonal antibodies targeting the glycine-rich domain potently reduced phase separation and aggregation of TDP-43 in vitro and prevented cellular uptake of preformed aggregates. Our unbiased screen suggests that targeting the RRM2 domain and the C-terminal region of TDP-43 by active or passive immunization may be beneficial in TDP-43 proteinopathies by inhibiting cardinal processes of disease progression.
AU  - Riemenschneider, H.*
AU  - Simonetti, F.*
AU  - Sheth, U.*
AU  - Katona, E.*
AU  - Roth, S.*
AU  - Hutten, S.*
AU  - Farny, D.*
AU  - Michaelsen, M.*
AU  - Nuscher, B.*
AU  - Schmidt, M.K.*
AU  - Flatley, A.
AU  - Schepers, A.
AU  - Gruijs da Silva, L.A.*
AU  - Zhou, Q.*
AU  - Klopstock, T.*
AU  - Liesz, A.*
AU  - Arzberger, T.*
AU  - Herms, J.*
AU  - Feederle, R.
AU  - Gendron, T.F.*
AU  - Dormann, D.*
AU  - Edbauer, D.*
C1  - 68117
C2  - 54595
CY  - Campus, 4 Crinan St, London N1 9xw, England
TI  - Targeting the glycine-rich domain of TDP-43 with antibodies prevents its aggregation in vitro and reduces neurofilament levels in vivo.
JO  - Acta Neuropathol. Commun.
VL  - 11
IS  - 1
PB  - Bmc
PY  - 2023
ER  - 

TY  - JOUR
AB  - Cerebellar dysfunction is commonly observed following traumatic brain injury (TBI). While direct impact to the cerebellum by TBI is rare, cerebellar pathology may be caused by indirect injury via cortico-cerebellar pathways. To address the hypothesis that degeneration of Purkinje cells (PCs), which constitute the sole output from the cerebellum, is linked to long-range axonal injury and demyelination, we used the central fluid percussion injury (cFPI) model of widespread traumatic axonal injury in mice. Compared to controls, TBI resulted in early PC loss accompanied by alterations in the size of pinceau synapses and levels of non-phosphorylated neurofilament in PCs. A combination of vDISCO tissue clearing technique and immunohistochemistry for vesicular glutamate transporter type 2 show that diffuse TBI decreased mossy and climbing fiber synapses on PCs. At 2 days post-injury, numerous axonal varicosities were found in the cerebellum supported by fractional anisotropy measurements using 9.4 T MRI. The disruption and demyelination of the cortico-cerebellar circuits was associated with poor performance of brain-injured mice in the beam-walk test. Despite a lack of direct input from the injury site to the cerebellum, these findings argue for novel long-range mechanisms causing Purkinje cell injury that likely contribute to cerebellar dysfunction after TBI.
AU  - Ozen, I.*
AU  - Mai, H.
AU  - de Maio, A.*
AU  - Ruscher, K.*
AU  - Michalettos, G.*
AU  - Clausen, F.*
AU  - Gottschalk, M.*
AU  - Ansar, S.*
AU  - Arkan, S.*
AU  - Ertürk, A.
AU  - Marklund, N.*
C1  - 66107
C2  - 53088
TI  - Purkinje cell vulnerability induced by diffuse traumatic brain injury is linked to disruption of long-range neuronal circuits.
JO  - Acta Neuropathol. Commun.
VL  - 10
IS  - 1
PY  - 2022
ER  - 

TY  - JOUR
AB  - Recent studies suggest that metabolic changes and oxygen deficiency in the central nervous system play an important role in the pathophysiology of multiple sclerosis (MS). In our present study, we investigated the changes in oxygenation and analyzed the vascular perfusion of the spinal cord in a rodent model of MS. We performed multispectral optoacoustic tomography of the lumbar spinal cord before and after an oxygen enhancement challenge in mice with experimental autoimmune encephalomyelitis (EAE), a model for MS. In addition, mice were transcardially perfused with lectin to label the vasculature and their spinal columns were optically cleared, followed by light sheet fluorescence microscopy. To analyze the angioarchitecture of the intact spine, we used VesSAP, a novel deep learning-based framework. In EAE mice, the spinal cord had lower oxygen saturation and hemoglobin concentration compared to healthy mice, indicating compromised perfusion of the spinal cord. Oxygen administration reversed hypoxia in the spinal cord of EAE mice, although the ventral region remained hypoxic. Additionally, despite the increased vascular density, we report a reduction in length and complexity of the perfused vascular network in EAE. Taken together, these findings highlight a new aspect of neuroinflammatory pathology, revealing a significant degree of hypoxia in EAE in vivo that is accompanied by changes in spinal vascular perfusion. The study also introduces optoacoustic imaging as a tractable technique with the potential to further decipher the role of hypoxia in EAE and to monitor it in MS patients.
AU  - Ramos-Vega, M.*
AU  - Kjellman, P.*
AU  - Todorov, M.I.
AU  - Kylkilahti, T.M.*
AU  - Bäckström, B.T.*
AU  - Ertürk, A.
AU  - Madsen, C.D.*
AU  - Lundgaard, I.*
C1  - 64797
C2  - 52496
TI  - Mapping of neuroinflammation-induced hypoxia in the spinal cord using optoacoustic imaging.
JO  - Acta Neuropathol. Commun.
VL  - 10
IS  - 1
PY  - 2022
ER  - 

TY  - JOUR
AB  - Autoimmune disorders of the central nervous system (CNS) comprise a broad spectrum of clinical entities. The stratification of patients based on the recognized autoantigen is of great importance for therapy optimization and for concepts of pathogenicity, but for most of these patients, the actual target of their autoimmune response is unknown. Here we investigated oligodendrocyte myelin glycoprotein (OMGP) as autoimmune target, because OMGP is expressed specifically in the CNS and there on oligodendrocytes and neurons. Using a stringent cell-based assay, we detected autoantibodies to OMGP in serum of 8/352 patients with multiple sclerosis, 1/28 children with acute disseminated encephalomyelitis and unexpectedly, also in one patient with psychosis, but in none of 114 healthy controls. Since OMGP is GPI-anchored, we validated its recognition also in GPI-anchored form. The autoantibodies to OMGP were largely IgG1 with a contribution of IgG4, indicating cognate T cell help. We found high levels of soluble OMGP in human spinal fluid, presumably due to shedding of the GPI-linked OMGP. Analyzing the pathogenic relevance of autoimmunity to OMGP in an animal model, we found that OMGP-specific T cells induce a novel type of experimental autoimmune encephalomyelitis dominated by meningitis above the cortical convexities. This unusual localization may be directed by intrathecal uptake and presentation of OMGP by meningeal phagocytes. Together, OMGP-directed autoimmunity provides a new element of heterogeneity, helping to improve the stratification of patients for diagnostic and therapeutic purposes.
AU  - Gerhards, R.*
AU  - Pfeffer, L.K.*
AU  - Lorenz, J.*
AU  - Starost, L.*
AU  - Nowack, L.*
AU  - Thaler, F.S.*
AU  - Schlüter, M.*
AU  - Rübsamen, H.*
AU  - Macrini, C.*
AU  - Winklmeier, S.*
AU  - Mader, S.*
AU  - Bronge, M.*
AU  - Grönlund, H.*
AU  - Feederle, R.
AU  - Hsia, H.E.*
AU  - Lichtenthaler, S.F.*
AU  - Merl-Pham, J.
AU  - Hauck, S.M.
AU  - Kuhlmann, T.*
AU  - Bauer, I.J.*
AU  - Beltran, E.*
AU  - Gerdes, L.A.*
AU  - Mezydlo, A.*
AU  - Bar-Or, A.*
AU  - Banwell, B.*
AU  - Khademi, M.*
AU  - Olsson, T.*
AU  - Hohlfeld, R.*
AU  - Lassmann, H.*
AU  - Kümpfel, T.*
AU  - Kawakami, N.*
AU  - Meinl, E.*
C1  - 60710
C2  - 49586
CY  - Campus, 4 Crinan St, London N1 9xw, England
TI  - Oligodendrocyte myelin glycoprotein as a novel target for pathogenic autoimmunity in the CNS.
JO  - Acta Neuropathol. Commun.
VL  - 8
IS  - 1
PB  - Bmc
PY  - 2020
ER  - 

TY  - JOUR
AB  - Hexanucleotide repeat expansion in C9orf72 is the most common genetic cause of frontotemporal dementia and amyotrophic lateral sclerosis, but the pathogenic mechanism of this mutation remains unresolved.Haploinsufficiency has been proposed as one potential mechanism. However, insights if and how reduced C9orf72 proteins levels might contribute to disease pathogenesis are still limited because C9orf72 expression, localization and functions in the central nervous system (CNS) are uncertain, in part due to the poor specificity of currently available C9orf72 antibodies.Here, we generated and characterized novel knock-out validated monoclonal rat and mouse antibodies against C9orf72. We found that C9orf72 is a low abundant, cytoplasmic, highly soluble protein with the long 481 amino acid isoform being the predominant, if not exclusively, expressed protein isoform in mouse tissues and human brain. As consequence of the C9orf72 repeat expansion, C9orf72 protein levels in the cerebellum were reduced to 80% in our series of C9orf72 mutation carriers (n = 17) compared to controls (n = 26). However, no associations between cerebellar protein levels and clinical phenotypes were seen. Finally, by utilizing complementary immunohistochemical and biochemical approaches including analysis of human iPSC derived motor neurons, we identified C9orf72, in addition to its association to lysosomes, to be localized to the presynapses and able to interact with all members of the RAB3 protein family, suggestive of a role for C9orf72 in regulating synaptic vesicle functions by potentially acting as guanine nucleotide exchange factor for RAB3 proteins.In conclusion, our findings provide further evidence for haploinsufficiency as potential mechanism in C9orf72 pathogenesis by demonstrating reduced protein levels in C9orf72 mutation carriers and important novel insights into the physiological role of C9orf72 in the CNS. Moreover, the described novel monoclonal C9orf72 antibodies will be useful tools to further dissect the cellular and molecular functions of C9orf72.
AU  - Frick, P.*
AU  - Sellier, C.*
AU  - Mackenzie, I.R.A.*
AU  - Cheng, C.*
AU  - Tahraoui-Bories, J.*
AU  - Martinat, C.*
AU  - Pasterkamp, R.J.*
AU  - Prudlo, J.*
AU  - Edbauer, D.*
AU  - Oulad-Abdelghani, M.*
AU  - Feederle, R.
AU  - Charlet-Berguerand, N.*
AU  - Neumann, M.*
C1  - 54149
C2  - 45325
CY  - Campus, 4 Crinan St, London N1 9xw, England
TI  - Novel antibodies reveal presynaptic localization of C9orf72 protein and reduced protein levels in C9orf72 mutation carriers.
JO  - Acta Neuropathol. Commun.
VL  - 6
PB  - Bmc
PY  - 2018
ER  - 

TY  - JOUR
AB  - INTRODUCTION: Natalizumab blocks α4-integrins and is a prototypic agent for a series of anti-inflammatory drugs that impair trafficking of immune cells into the CNS. However, modulation of the access of immune cells to the CNS is associated with impaired immune surveillance and detrimental viral infections of the CNS. Here, we explored the potency of cellular immune responses within the CNS to protect against viral encephalitis in mice with T cell conditional disruption of VLA-4 integrin (α4β1) expression. RESULTS: While VLA-4 expression in virus specific Th1 cells is non-redundant for their ability to access the CNS, α4-integrin deficient Th17 cells enter the CNS compartment and generate an inflammatory milieu upon intrathecal vaccinia virus (VV) infection. However, in contrast to Th1 cells that can adopt direct cytotoxic properties, Th17 cells fail to clear the virus due to insufficient Eomes induced perforin-1 expression. CONCLUSION: The quality of the intrathecal cellular antiviral response under conditions of impaired VLA-4 function jeopardizes host protection. Our functional in vivo data extend our mechanistic understanding of anti-viral immunity in the CNS and help to estimate the risk potential of upcoming therapeutic agents that target the trafficking of immune cells into distinct anatomical compartments.
AU  - Rothhammer, V.*
AU  - Muschaweckh, A.
AU  - Gasteiger, G.*
AU  - Petermann, F.*
AU  - Heink, S.*
AU  - Busch, D.*
AU  - Heikenwälder, M.
AU  - Hemmer, B.*
AU  - Drexler, I.*
AU  - Korn, T.*
C1  - 30883
C2  - 33956
TI  - α4-integrins control viral meningoencephalitis through differential recruitment of T helper cell subsets.
JO  - Acta Neuropathol. Commun.
VL  - 2
IS  - 1
PY  - 2014
ER  - 

TY  - JOUR
AB  - ACKGROUND: Neuromyelitis optica (NMO) is an inflammatory demyelinating disease of the central nervous system (CNS), which is characterized by the presence of pathogenic serum autoantibodies against aquaporin 4 (AQP4) in the vast majority of patients. The contribution of T cells to the formation of astrocyte destructive lesions is currently unclear. However, active human NMO lesions contain CD4+ T-lymphocytes expressing the activation marker Ox40, and the expression is more profound compared to that seen in MS lesions of comparable activity. Therefore, we analyzed the role of T-cell activation within the CNS in the initiation of NMO lesions in an experimental model of co-transfer of different encephalitogenic T-cells and human AQP4 antibody containing NMO immunoglobulin (NMO IgG). We further studied the expression of the T-cell activation marker Ox40 in NMO and multiple sclerosis lesions in different stages of activity. RESULTS: All encephalitogenic T-cell lines used in our experiments induced brain inflammation with a comparable extent of blood brain barrier damage, allowing human NMO IgG to penetrate into the brain and spinal cord tissue. However, astrocyte destructive NMO lesions were only seen with T-cells, which showed signs of activation in the lesions. T-cell activation was reflected by the expression of the activation marker Ox40 and pronounced production of γ-IFN, which was able to increase the production of complement proteins and of the Fc gamma III receptor (Fcgr3) and decreased production of complement inhibitory protein Factor H in microglia. CONCLUSIONS: Our data indicate that local activation of T-cells provide an inflammatory environment in the CNS, which allows AQP4 auto-antibodies to induce astrocyte destructive NMO-like lesions.
AU  - Pohl, M.*
AU  - Kawakami, N.*
AU  - Kitic, M.*
AU  - Bauer, J.*
AU  - Martins, R.*
AU  - Fischer, M.T.*
AU  - Machado-Santos, J.*
AU  - Mader, S.*
AU  - Ellwart, J.W.
AU  - Misu, T.*
AU  - Fujihara, K.*
AU  - Wekerle, H.*
AU  - Reindl, M.*
AU  - Lassmann, H.*
AU  - Bradl, M.*
C1  - 29086
C2  - 33629
TI  - T cell-activation in neuromyelitis optica lesions plays a role in their formation.
JO  - Acta Neuropathol. Commun.
VL  - 1
IS  - 1
PY  - 2013
ER  -