@unpublished{SchaeferJanzenBakircietal.2019, author = {Schaefer, Natascha and Janzen, Dieter and Bakirci, Ezgi and Hrynevich, Andrei and Dalton, Paul D. and Villmann, Carmen}, title = {3D Electrophysiological Measurements on Cells Embedded within Fiber-Reinforced Matrigel}, series = {Advanced Healthcare Materials}, journal = {Advanced Healthcare Materials}, doi = {10.1002/adhm.201801226}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-244194}, year = {2019}, abstract = {2D electrophysiology is often used to determine the electrical properties of neurons, while in the brain, neurons form extensive 3D networks. Thus, performing electrophysiology in a 3D environment provides a closer situation to the physiological condition and serves as a useful tool for various applications in the field of neuroscience. In this study, we established 3D electrophysiology within a fiber-reinforced matrix to enable fast readouts from transfected cells, which are often used as model systems for 2D electrophysiology. Using melt electrowriting (MEW) of scaffolds to reinforce Matrigel, we performed 3D electrophysiology on a glycine receptor-transfected Ltk-11 mouse fibroblast cell line. The glycine receptor is an inhibitory ion channel associated when mutated with impaired neuromotor behaviour. The average thickness of the MEW scaffold was 141.4 ± 5.7µm, using 9.7 ± 0.2µm diameter fibers, and square pore spacings of 100 µm, 200 µm and 400 µm. We demonstrate, for the first time, the electrophysiological characterization of glycine receptor-transfected cells with respect to agonist efficacy and potency in a 3D matrix. With the MEW scaffold reinforcement not interfering with the electrophysiology measurement, this approach can now be further adapted and developed for different kinds of neuronal cultures to study and understand pathological mechanisms under disease conditions.}, language = {en} } @article{DopplerSchusterAppeltshauseretal.2019, author = {Doppler, Kathrin and Schuster, Yasmin and Appeltshauser, Luise and Biko, Lydia and Villmann, Carmen and Weishaupt, Andreas and Werner, Christian and Sommer, Claudia}, title = {Anti-CNTN1 IgG3 induces acute conduction block and motor deficits in a passive transfer rat model}, series = {Journal of Neuroinflammation}, volume = {16}, journal = {Journal of Neuroinflammation}, number = {73}, doi = {10.1186/s12974-019-1462-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200476}, year = {2019}, abstract = {Background: Autoantibodies against the paranodal protein contactin-1 have recently been described in patients with severe acute-onset autoimmune neuropathies and mainly belong to the IgG4 subclass that does not activate complement. IgG3 anti-contactin-1 autoantibodies are rare, but have been detected during the acute onset of disease in some cases. There is evidence that anti-contactin-1 prevents adhesive interaction, and chronic exposure to anti-contactin-1 IgG4 leads to structural changes at the nodes accompanied by neuropathic symptoms. However, the pathomechanism of acute onset of disease and the pathogenic role of IgG3 anti-contactin-1 is largely unknown. Methods: In the present study, we aimed to model acute autoantibody exposure by intraneural injection of IgG of patients with anti-contacin-1 autoantibodies to Lewis rats. Patient IgG obtained during acute onset of disease (IgG3 predominant) and IgG from the chronic phase of disease (IgG4 predominant) were studied in comparison. Results: Conduction blocks were measured in rats injected with the "acute" IgG more often than after injection of "chronic" IgG (83.3\% versus 35\%) and proved to be reversible within a week after injection. Impaired nerve conduction was accompanied by motor deficits in rats after injection of the "acute" IgG but only minor structural changes of the nodes. Paranodal complement deposition was detected after injection of the "acute IgG". We did not detect any inflammatory infiltrates, arguing against an inflammatory cascade as cause of damage to the nerve. We also did not observe dispersion of paranodal proteins or sodium channels to the juxtaparanodes as seen in patients after chronic exposure to anti-contactin-1. Conclusions: Our data suggest that anti-contactin-1 IgG3 induces an acute conduction block that is most probably mediated by autoantibody binding and subsequent complement deposition and may account for acute onset of disease in these patients. This supports the notion of anti-contactin-1-associated neuropathy as a paranodopathy with the nodes of Ranvier as the site of pathogenesis.}, language = {en} } @article{StengelVuralBrunderetal.2019, author = {Stengel, Helena and Vural, Atay and Brunder, Anna-Michelle and Heinius, Annika and Appeltshauser, Luise and Fiebig, Bianca and Giese, Florian and Dresel, Christian and Papagianni, Aikaterini and Birklein, Frank and Weis, Joachim and Huchtemann, Tessa and Schmidt, Christian and K{\"o}rtvelyessy, Peter and Villmann, Carmen and Meinl, Edgar and Sommer, Claudia and Leypoldt, Frank and Doppler, Kathrin}, title = {Anti-pan-neurofascin IgG3 as a marker of fulminant autoimmune neuropathy}, series = {Neurology: Neuroimmunology \& Neuroinflammation}, volume = {6}, journal = {Neurology: Neuroimmunology \& Neuroinflammation}, number = {5}, doi = {10.1212/NXI.0000000000000603}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-202462}, year = {2019}, abstract = {Objective To identify and characterize patients with autoantibodies against different neurofascin (NF) isoforms. Methods Screening of a large cohort of patient sera for anti-NF autoantibodies by ELISA and further characterization by cell-based assays, epitope mapping, and complement binding assays. Results Two different clinical phenotypes became apparent in this study: The well-known clinical picture of subacute-onset severe sensorimotor neuropathy with tremor that is known to be associated with IgG4 autoantibodies against the paranodal isoform NF-155 was found in 2 patients. The second phenotype with a dramatic course of disease with tetraplegia and almost locked-in syndrome was associated with IgG3 autoantibodies against nodal and paranodal isoforms of NF in 3 patients. The epitope against which these autoantibodies were directed in this second phenotype was the common Ig domain found in all 3 NF isoforms. In contrast, anti-NF-155 IgG4 were directed against the NF-155-specific Fn3Fn4 domain. The description of a second phenotype of anti-NF-associated neuropathy is in line with some case reports of similar patients that were published in the last year. Conclusions Our results indicate that anti-pan-NF-associated neuropathy differs from anti-NF-155-associated neuropathy, and epitope and subclass play a major role in the pathogenesis and severity of anti-NF-associated neuropathy and should be determined to correctly classify patients, also in respect to possible differences in therapeutic response.}, language = {en} } @article{KitzenmaierSchaeferKasaragodetal.2019, author = {Kitzenmaier, Alexandra and Schaefer, Natascha and Kasaragod, Vikram Babu and Polster, Tilman and Hantschmann, Ralph and Schindelin, Hermann and Villmann, Carmen}, title = {The P429L loss of function mutation of the human glycine transporter 2 associated with hyperekplexia}, series = {European Journal of Neuroscience}, volume = {50}, journal = {European Journal of Neuroscience}, number = {12}, doi = {10.1111/ejn.14533}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-206158}, pages = {3906-3920}, year = {2019}, abstract = {Glycine transporter 2 (GlyT2) mutations across the entire sequence have been shown to represent the presynaptic component of the neurological disease hyperekplexia. Dominant, recessive and compound heterozygous mutations have been identified, most of them leading to impaired glycine uptake. Here, we identified a novel loss of function mutation of the GlyT2 resulting from an amino acid exchange of proline 429 to leucine in a family with both parents being heterozygous carriers. A homozygous child suffered from severe neuromotor deficits. We characterised the GlyT2P429L variant at the molecular, cellular and protein level. Functionality was determined by glycine uptake assays. Homology modelling revealed that the mutation localises to α-helix 5, presumably disrupting the integrity of this α-helix. GlyT2P429L shows protein trafficking through various intracellular compartments to the cellular surface. However, the protein expression at the whole cell level was significantly reduced. Although present at the cellular surface, GlyT2P429L demonstrated a loss of protein function. Coexpression of the mutant with the wild-type protein, reflecting the situation in the parents, did not affect transporter function, thus explaining their non-symptomatic phenotype. Nevertheless, when the mutant was expressed in excess compared with the wild-type protein, glycine uptake was significantly reduced. Thus, these data demonstrate that the proline residue at position 429 is structurally important for the correct formation of α-helix 5. The failure in functionality of the mutated GlyT2 is most probably due to structural changes localised in close proximity to the sodium-binding site of the transporter.}, language = {en} }