

The goal of our research is to link the molecular mechanisms of mainly genetic, neurological diseases caused by disturbed neuronal excitability to their clinical symptoms and a personalized treatment. We are recruiting well-defined cohorts of patients with epilepsies and related disorders, searching for disease-causing genetic defects with modern sequencing techniques, particularly in ion channels or transporters, and analyzing their functional consequences to understand the pathomechanisms. A particular focus is
on finding and exploring new personalized therapies for genetic disorders. To study mechanisms of neuronal hyperexcitability on the molecular, cellular and network level, we use non-neuronal screening tools such as automated electrophysiology in oocytes and mammalian cells, neuronal expression systems including neurons derived from induced pluripotent stem cells and human brain slices, and gene-targeted mouse models.
Genetics and pharmacogenetics of epilepsy
Epilepsy affects up to 3% of people during their lifetime, with a genetic component playing a major pathophysiological role in almost 50% of cases. To analyze the genetic architecture of epilepsy we have initiated running national research networks (Treat-ION, DFG FOR-2715) and have initiated or been part of still ongoing European (ESF: EuroEPINOMICS, FP7: EpiPGX, ERANet Neuron: SNAREopathies) and international (ILAE consortium on the genetics of complex epilepsies, Epi25, ILAE Genomics) networks confi ned to the recruitment of large cohorts of affected individuals and/or families and their genetic analyses. Major achievements in the last years were the prolongation of our DFG-Research Unit FOR 2715, entitled Epileptogenesis of Genetic Epilepsies, establishing Treat-ION, a
BMBF-funded network for rare ion channel disorders in 2019 (prolongation pending), and founding ILAE
Genomics to collect all available exomes sequenced in epilepsy patients wolrdwide. Important examples from recent studies are the identifi cation of 4-aminopyridine as a new and specifi c (‘precision’) treatment for a severe epilepsy with developmental problems of early childhood caused
by mutations in KCNA2 (Hedrich, Lauxmann et al. Sci Transl Med 2021), the identifi cation of a new mechanism for migraine aura in an Scn1a mouse model (Auffenberg, Hedrich et al., JCI 2021), and very clear genotype-phenotype correlations with high relevance for clinical management for SCN8A-related epilepsies (Johannesen, Liu et al., Brain 2021). A bioinformatic study in a large dataset of whole exomes from more than 8000 affected individuals with common epilepsies revealed that important functional gene groups, such as those of synaptic genes and ion channels / receptors, show specifi c
patterns of enrichment of pathological variants compared to controls in generalized vs. focal epilepsies (e.g. affecting inhibitory vs. excitatory pathways), and also show that signals from common and rare variants converge and contrast in generalized vs. focal epilepsies.
Functional investigations of genetic defects in ion channels
With the BMBF-funded Treat-ION consortium on Neurological Ion Channel and Transporter Disorders we focus on therapeutic studies in cellular, animal and human models, which are complemented by in silico searches for new treatments, better predictions for the functional consequences of mutations
for therapeutic purposes and cellular drug screens. The use of approved and available ‘repurposed’ drugs such as 4-aminopyridine is a a specific goal to enable precision treatment. Our findings are directly delivered to patients through molecular therapeutic boards attached to the German academy of
rare neurological diseases (DASNE) and the centers for rare diseases (ZSEs) in Baden-Württemberg and through a structured process for drug repurposing. Functional implications of selected mutations are examined in neuronal expression systems, such as transfected murine primary neurons,
in utero electroporated neurons and genetically altered animal models carrying a human mutation (so-called “humanized mouse models”). The advantage of both in utero electroporated neurons and gene-targeted mouse models is that altered channels can be studied in their natural environment
and additionally, the consequences on intrinsic neuronal properties and network activity can be studied
using single cell patch clamp, extracellular recording or multielectrode array (MEA) techniques. We perform 256 electrode MEA recordings and high-resolution electrical imaging (CMOS with 4000 electrodes) to analyze single cell compartments and neuronal network activity in brain slices of transgenic animals and study network dysfunction of our mouse models in vivo together with
O. Garaschuk (Inst. Neurophysiology) using Ca2+imaging in the frame of the DFG Research Unit. To gain insight into the exact mechanisms as to how epilepsy develops as a consequence of
a genetic defect, we investigate brain region- and time-specific RNA expression using single cell RNA sequencing in distinct neuronal subpopulations in mouse models.

Induced pluripotent stem cells as epilepsy models
Finally, we reprogram fibroblasts obtained from patients carrying different epilepsy-causing mutations in ion channel genes to generate human induced pluripotent cells (hiPSC). Like embryonic stem cells, iPSCs can be differentiated into excitatory and inhibitory cortical neurons and glial cells by addition of different growth factors, defined culture conditions or by overexpression of transcription factors. Thus, it is possible to investigate cortical cells, which were previously inaccessible, from patients carrying
genetic diversity or specific mutations of epileptic syndromes. We showed that developmental electrophysiological patterns are similar in iPSC-derived neurons as compared to known data
from animals and human tissue and that ipSC-derived neurons represent a study (Rosa et al., Stem Cell Rep 2020). In ongoing work, we characterize firing behaviour and synaptic characteristics of single neurons and networks plated on MEAs.
Research staff: Filip Rosa, Nikolas Schwarz, Carolin Haag
Human brain slices cultures
As another human model system, we are using human slice cultures which can be maintained for up to four weeks with good neurophysiological properties when human cerebrospinal fluid (CSF) is used as culture medium. The use of ex vivo brain slices derived from adult human neurosurgical-resected tissue allows to probe electrophysiological properties at single cell and network level (Schwarz et al., Sci Rep 2017). We demonstrated robust preservation of neuronal cytoarchitecture and electrophysiological properties of human pyramidal neurons. Further experiments delineate the optimal conditions for efficient viral transduction of cultures, enabling ‘high throughput’ fluorescence-mediated 3D reconstruction of genetically targeted neurons, and demonstrate feasibility of long term live cell imaging of human cells in vitro.
Research staff: Nikolas Schwarz, Carolin Haag


Selected Publications
Müller P*, Takacs DS*, Hedrich UBS, Coorg R, Masters L, Glinton KE, Dai H, Cokley JA, Riviello JJ, Lerche H#, Cooper EC#. KCNA1 gain-of-function epileptic encephalopathy treated with 4-aminopyridine. Ann Clin Transl Neurol. 2023 Feb 15.
Krüger J, Schubert J, Kegele J, Labalme A, Mao M, Heighway J, Seebohm G, Yan P, Koko M, Aslan-Kara K, Caglayan H, Steinhoff BJ, Weber YG, Keo-Kosal P, Berkovic SF, Hildebrand MS, Petrou S, Krause R, May P, Lesca G, Maljevic S, Lerche H. Loss-of-function variants in the KCNQ5 gene are implicated in genetic generalized epilepsies. EBioMedicine. 2022 Oct;84:104244. doi: 10.1016/j.ebiom.2022.104244.
Johannesen KM*, Liu Y*, Koko M, Gjerulfsen CE, Sonnenberg L, Schubert J, Fenger CD, Eltokhi A, Rannap M, Koch NA,Lauxmann S, Krüger J, Kegele J, (…),Hedrich UBS, Benda J, Gardella E,Lerche H#, Møller RS#. Genotype-phenotype correlations in SCN8A-related disorders reveal prognostic and therapeutic implications. Brain 2021:awab321.
Auffenberg E*, Hedrich UB*, Barbieri R*, Miely D*, Groschup B, Wuttke TV, (…), Pusch M, Dichgans M, Lerche H, Gavazzo P#, Plesnila N#, Freilinger T#. Hyperexcitable interneurons trigger cortical spreading depression in an Scn1a migraine model. J Clin Invest 2021;131:e142202.
Hedrich UBS*, Lauxmann S*, (…), Bosselmann C, Schwarz N, Fudali M, Lerche H. 4-Aminopyridine is a promising treatment option for patients with gain-of-function KCNA2-encephalopathy. Sci Transl Med 2021;13:eaaz4957.
Koko M, Krause R, Sander T, Bobbili DR, Nothnagel M, May P,Lerche H; Epi25 Collaborative. Distinct gene-set burden patterns underlie common generalized and focal epilepsies. EBioMedicine 2021;72:103588.
Rosa F, Dhingra A, Uysal B, Mendis GDC, Loeffler H, Elsen G, Mueller S, Schwarz N, Castillo-Lizardo M, Cuddy C, Becker F, Heutink P, Reid CA, Petrou S, Lerche H#, Maljevic S#. In Vitro Differentiated Human Stem Cell-Derived Neurons Reproduce Synaptic Synchronicity Arising during Neurodevelopment. Stem Cell Reports 2020;15:22-37.
Schwarz N, Hedrich UBS, Schwarz H, P A H, Dammeier N, Auffenberg E, Bedogni F, Honegger JB, Lerche H, Wuttke TV, Koch H. Human Cerebrospinal fluid promotes long-term neuronal viability and network function in human neocortical organotypic brain slice cultures. Sci Rep. 2017 Sep 25;7(1):12249.

Center of Neurology
Hertie Institute for Clinical Brain Research
Department Neurology and Epileptology
Hoppe-Seyler-Straße 3
72076 Tübingen
Phone: +49 (0)7071 29-80442
Fax: +49 (0)7071 29-4488
Sabrina Kreiser
Yvonne Brändle
Phone: +49 (0)7071 29-80442
Fax: +49 (0)7071 29-4488
sekretariatne5.HL@med.uni-tuebingen.de
Heidrun Löffler
Phone: +49 (0)7071 29-81922
heidi.loeffler@medizin.uni-tuebingen.de