Our research group is interested to unravel the mechanisms of well defined, mainly genetic, neurological, paroxysmal diseases, to understand correlations with clinical symptoms and to find new treatment options.
Our main goals are:
- to find out specific disease-causing genetic defects
- to understand their molecular, cellular and network mechanisms
- to improve existing or develop new therapies
The research is focused on diseases with a disturbed neuronal excitability, such as epilepsy and migraine, which are caused by mutations in genes encoding ion channels, receptors or transporters. Disease mechanisms are examined in detail using molecular biological and electrophysiological techniques by studying the defects of disease-causing mutations and their consequences on protein characteristics, channel gating, intrinsic neuronal properties and behaviour of neuronal networks. The ultimate goal is to predict response to specific existing and newly developed therapies for each of the examined diseases based on the explored mechanisms in the sense of personalized medicine.
Genetics and pharmacogenetics of epilepsy
Epilepsy affects approximately 3% of people during their lifetime. Up to 50% of all epilepsy patients suffer from so-called "idiopathic epilepsies", which are genetic in origin and not caused by structural or metabolic brain abnormalities. We are interested to identify genetic defects and risk factors in monogenic and complex genetic forms of epilepsies and related disorders by using whole genome association studies and next generation sequencing techniques on a gene-panel, whole exome and whole genome level. These studies are performed in close collaboration with other groups in Germany, Europe and overseas countries using the advantages of large scale collaborative projects to increase resources, sample size and expertise (NGFNplus EMINet, EuroEPINOMICS – collaboration with NIH-funded Epi4k and Canadian CENet project, IonNeurONet).Pharmacogenetics is a relatively new field of research dealing with genetic constellations that are associated with drug response or side effects. The vision of such research is to predict the response to antiepileptic drugs and adverse events on the basis of specific genotypes. One such example exists and is already in clinical use to predict life-threatening allergic skin reactions to carbamazepine in the South-Asian population (Chen et al., N Engl J Med 2011;364:1126-33). We are systematically exploring the influences of genetics on drug response in epilepsy in the European FP7 project EpiPGX.Research staff: Julian Schubert, Stephan Wolking, Josua Kegele, Felicitas Becker, Christian Hengsbach, Sarah Rau, close collaboration with AG Weber
Functional investigations of genetic defects in ion channels
Many of the mutations identified so far in idiopathic/genetic epilepsy syndromes affect genes encoding ion channels. These membrane proteins tune the neuronal transmembrane voltage by opening and closing ("gating") in response to either synaptic neuromediators (ligand-gated channels) or changes in the voltage itself (voltage-gated channels). In this way, genetic mutations affecting these channels can alter neuronal excitability and potentially drive a network of neurons into synchrony to promote a seizure. This conclusion is supported by the fact that most of the antiepileptic drugs in clinical use today modulate different types of ion channels or synaptic proteins.Our group has a long-standing experience with structure-function analysis, the gating properties and pharmacology of ion channels using molecular biological and electrophysiological techniques. We have been functionally characterizing disease-causing mutations of different ion channels including voltage-gated sodium, potassium, calcium and chloride channels as well as ligand-gated channels, such as GABA and glutamate receptors. Many of our studies have been carried out in heterologous expression systems, such as Xenopus laevis oocytes or mammalian cell lines, which usually do not contain the molecule of interest, providing the possibility to study the molecular impact of a disease mutation using electrophysiological, biochemical and immunocytochemistry approaches.Research staff: Ulrike Hedrich, Yuanyuan Liu, Gina Elsen, Thomas Wuttke, Stefan Lauxmann, Natalie Winter, Stefanie Hayer, Nicole Jezutkovic, Heidi Löffler, close collaboration with AG Maljevic
Fig. legend: Mutations in the KCNA2 gene, encoding the KV1.2 potassium channel, have been recently shown to cause severe forms of epilepsy and developmental delay (so-called epileptic encephalopathies) (Syrbe, Hedrich et al. 2015). The figure shows a functional analysis of KV1.2 mutations using Xenopus laevis oocytes. Mutations in KCNA2 interestingly can either cause a gain (red box) or a loss of function of KV1.2 channels (blue box). Shown are KV1.2-mediated potassium currents recorded from oocytes expressing wildtype (top traces) or mutant (bottom traces) channels by using an automated two-electrode voltage-clamp system (top in the middle; picture from www.multichannels.com). Oozytes are impaled with two electrodes (bottom in the middle), potassium currents are recorded during application of increasing voltage steps (figures of current recordings derived from Syrbe, Hedrich et al. 2015). Currents conducted by channels with gain-of-function mutations can be significantly reduced by application of 4-Aminopyridine (not shown). As 4-Aminopyridine is a licensed drug, it is now tried in patients to relieve symptoms of the disease, such as seizures, impaired cognition and ataxia.
Neuronal expression systems and genetic mouse models
To further study the effects of human mutations causing epilepsy in neurons, we are using transfected primary cultures from mice and genetically altered animal models carrying a human mutation (so-called “humanized mouse models”). In comparison to heterologous expression systems, in neurons the channels can be studied in their natural environment and the consequences on intrinsic neuronal properties can be examined. Furthermore, mouse models mimic the clinical features of the affected patients and provide the possibility to examine the effects of disease causing mutations under physiological conditions. By using such mouse models we are able to study the disease mechanisms in single neurons, neuronal networks and in the living animal. We mainly use the patch clamp technique in brain slices to record the gating properties of channels in neurons and neuronal properties. Networks are studied with multiple extracellular electrodes and multielectrode arrays. In cooperation with Cornelius Schwarz (CIN) we work on in vivo recordings of responses to specific sensory stimuli (whisker stimulation), and together with Olga Garaschuk (Inst. of Physiology II) we work on in vivo 2-photon recordings of neuronal networks.
Fig. legend: Mouse models are used to study human disease-causing mutations. (A) Schematic of a thalamocortical brain slice of a genetically altered mouse. (B) Neuron filled with a fluorescent dye during whole-cell patch clamp recording. Shown is a train of action potentials elicited by current injection.
Induced pluripotent stem cells as epilepsy models
We are reprogramming fibroblasts and keratinocytes obtained from patients carrying different epilepsy-causing mutations in ion channel genes to generate human induced pluripotent cells (hiPSC). Using selected differentiation protocols, the hiPSC are further differentiated into different types of neuronal cells, which are characterized using electrophysiological, immunocytochemical and biochemical assays.
Research staff: Stephan Müller, Heidi, Löffler, Niklas Schwarz, Gina Elsen, close collaboration with AG Maljevic
Epilepsy and the central control of breathing
Breathing is essential for life and a dysfunction of the neuronal network that controls this behaviour is suspected to be involved in several neurological diseases. The PreBötzinger Complex (PreBötC, Fig1A) is the central generator of the inspiratory breathing activity located in the brainstem (Fig1B2 and 1B3)
We aim to unravel the consequences, of known epilepsy-causing mutations in genes encoding voltage gated sodium-channels, on the function of the PreBötC. The project aims to investigate the breathing activity in vivo and in vitro in mice with targeted knock-out and knock-in mutations in these genes and their possible consequences for SUDEP (sudden unexpected death in epilepsy).
Fig. legend: (A) Representative plethysmographic recording of the breathing activity of unanesthetized and unrestrained mice (note that eupnea is interrupted by larger biphasic breaths, which are termed sighs). (B1) Schematic drawing of the anatomy of the PreBötzinger Complex in the transverse slice preparation (Amb: Nucleus Ambiguus, XII: Hypoglossal Nucleus, SP5: Spinal Trigeminal Nucleus). (B2) Representative multiunit population and simultaneous intracellular recording of the activity produced in the Prebötzinger Complex in isolation. (B3) Shown is a longer sample of the activity generated in the PreBötC, note the two distinct patterns in vivo and in vitro: sighs (*) and eupnea.
Further we plan to investigate the breathing pattern of patients suffering from chronic epilepsy during the pre-surgical monitoring. To achieve this we will quantify the respiratory frequency, variability of respiration (amplitude and frequency) and the heartrate variability as a measure of autonomic dysfunction in epileptic and non-epileptic patients and investigtae the influence of antiepileptic drug treatment on these patterns.
Research staff: Henner Koch, Stephan Lauxmann, Nicole Kusch
Selected Publications (sorted by topics)
Genetics and functional investigations
De novo loss- or gain-of-function mutations in KCNA2 cause epileptic encephalopathy.Syrbe S, Hedrich UB*, Riesch E, Djémié T, Müller S, Møller RS, Maher B, Hernandez-Hernandez L, Synofzik M, Caglayan HS, Arslan M, Serratosa JM, Nothnagel M, May P, Krause R, Löffler H, Detert K, Dorn T, Vogt H, Krämer G, Schöls L, Mullis PE, Linnankivi T, Lehesjoki AE, Sterbova K, Craiu DC, Hoffman-Zacharska D, Korff CM, Weber YG, Steinlin M, Gallati S, Bertsche A, Bernhard MK, Merkenschlager A, Kiess W; EuroEPINOMICS RES, Gonzalez M, Züchner S, Palotie A, Suls A, De Jonghe P, Helbig I, Biskup S, Wolff M, Maljevic S, Schüle R, Sisodiya SM, Weckhuysen S, Lerche H#, Lemke JR.
Nat Genet 2015;47:393-9.
*,#equally contributing first author or principle investigator/corresponding author
A recurrent de novo mutation in KCNC1 causes progressive myoclonus epilepsy. Muona M, Berkovic SF, Dibbens LM, Oliver KL, Maljevic S, Bayly MA, Joensuu T, Canafoglia L, Franceschetti S, Michelucci R, Markkinen S, Heron SE, Hildebrand MS, Andermann E, Andermann F, Gambardella A, Tinuper P, Licchetta L, Scheffer IE, Criscuolo C, Filla A, Ferlazzo E, Ahmad J, Ahmad A, Baykan B, Said E, Topcu M, Riguzzi P, King MD, Ozkara C, Andrade DM, Engelsen BA, Crespel A, Lindenau M, Lohmann E, Saletti V, Massano J, Privitera M, Espay AJ, Kauffmann B, Duchowny M, Møller RS, Straussberg R, Afawi Z, Ben-Zeev B, Samocha KE, Daly MJ, Petrou S, Lerche H, Palotie A, Lehesjoki AE.
Nat Genet 2015;47:39-46.
Mutations in STX1B, encoding a presynaptic protein, cause fever-associated epilepsy syndromes. Schubert J, Siekierska A, Langlois M, May P, Huneau C, Becker F, Muhle H, Suls A, Lemke JR, de Kovel CG, Thiele H, Konrad K, Kawalia A, Toliat MR, Sander T, Rüschendorf F, Caliebe A, Nagel I, Kohl B, Kecskés A, Jacmin M, Hardies K, Weckhuysen S, Riesch E, Dorn T, Brilstra EH, Baulac S, Møller RS, Hjalgrim H, Koeleman BP; EuroEPINOMICS RES Consortium, Jurkat-Rott K, Lehman-Horn F, Roach JC, Glusman G, Hood L, Galas DJ, Martin B, de Witte PA, Biskup S, De Jonghe P, Helbig I, Balling R, Nürnberg P, Crawford AD, Esguerra CV, Weber YG#, Lerche H.
Nat Genet 2014;46:1327-32.
#equally contributing principle investigator
De novo mutations in synaptic transmission genes including DNM1 cause epileptic encephalopathies. EuroEPINOMICS-RES Consortium; Epilepsy Phenome/Genome Project; Epi4K Consortium.
Am J Hum Genet 2014;95:360-70.
Genetic determinants of common epilepsies: a meta-analysis of genome-wide association studies. International League Against Epilepsy Consortium on Complex Epilepsies.
Lancet Neurol 2014;13:893-903.
Mutations in GRIN2A cause idiopathic focal epilepsy with rolandic spikes.
Lemke JR, Lal D, Reinthaler EM, Steiner I, Nothnagel M, Alber M, Geider K, Laube B, Schwake M, Finsterwalder K, Franke A, Schilhabel M, Jähn JA, Muhle H, Boor R, Van Paesschen W, Caraballo R, Fejerman N, Weckhuysen S, De Jonghe P, Larsen J, Møller RS, Hjalgrim H, Addis L, Tang S, Hughes E, Pal DK, Veri K, Vaher U, Talvik T, Dimova P, Guerrero López R, Serratosa JM, Linnankivi T, Lehesjoki AE, Ruf S, Wolff M, Buerki S, Wohlrab G, Kroell J, Datta AN, Fiedler B, Kurlemann G, Kluger G, Hahn A, Haberlandt DE, Kutzer C, Sperner J, Becker F, Weber YG, Feucht M, Steinböck H, Neophythou B, Ronen GM, Gruber-Sedlmayr U, Geldner J, Harvey RJ, Hoffmann P, Herms S, Altmüller J, Toliat MR, Thiele H, Nürnberg P, Wilhelm C, Stephani U, Helbig I, Lerche H*, Zimprich F, Neubauer BA, Biskup S, von Spiczak S*.
Nat Genet 2013;45:1067-72.
Molecular correlates of age-dependent seizures in an inherited neonatal-infantile epilepsy.
Liao Y, Deprez L, Maljevic S, Pitsch J, Claes L, Hristova D, Jordanova A, Ala-Mello S, Bellan-Koch A, Blazevic D, Schubert S, Thomas EA, Petrou S, Becker AJ, De Jonghe P, Lerche H.
15q13.3 microdeletions increase risk of idiopathic generalized epilepsy.
Helbig I, Mefford HC, Sharp AJ, Guipponi M, Fichera M, Franke A, Muhle H, de Kovel C, Baker C, von Spiczak S, Kron KL, Steinich I, Kleefuss-Lie AA, Leu C, Gaus V, Schmitz B, Klein KM, Reif PS, Rosenow F, Weber Y, Lerche H, Zimprich F, Urak L, Fuchs K, Feucht M, Genton P, Thomas P, Visscher F, de Haan GJ, Møller RS, Hjalgrim H, Luciano D, Wittig M, Nothnagel M, Elger CE, Nürnberg P, Romano C, Malafosse A, Koeleman BP, Lindhout D, Stephani U, Schreiber S, Eichler EE, Sander T.
Nat Genet 2009;41:160-2.
GLUT1 mutations are a cause of paroxysmal exertion-induced dyskinesias and induce hemolytic anemia by a cation leak.
Weber YG, Storch A, Wuttke TV, Brockmann K, Kempfle J, Maljevic S, Margari L, Kamm C, Schneider SA, Huber SM, Pekrun A, Roebling R, Seebohm G, Koka S, Lang C, Kraft E, Blazevic D, Salvo-Vargas A, Fauler M, Mottaghy FM, Münchau A, Edwards MJ, Presicci A, Margari F, Gasser T, Lang F, Bhatia KP, Lehmann-Horn F, Lerche H.
J Clin Invest 2008;118:2157-68.
Genetic biomakers in epilepsy.
Weber YG, Nies AT, Schwab M, Lerche H.
Ion channels in genetic and acquired forms of epilepsy.
Lerche H, Shah M, Beck H, Noebels J, Johnston D, Vincent A.
J Physiol 2013;591:753-64.
Genetic mouse models
Impaired action potential initiation in GABAergic interneurons causes hyperexcitable networks in an epileptic mouse model carrying a human Na(V)1.1 mutation.
Hedrich UB, Liautard C, Kirschenbaum D, Pofahl M, Lavigne J, Liu Y, Theiss S, Slotta J, Escayg A, Dihné M, Beck H, Mantegazza M, Lerche H.
J Neurosci 2014;34:14874-89.
Reduced dendritic arborization and hyperexcitability of pyramidal neurons in a Scn1b-based model of Dravet syndrome.
Reid CA, Leaw B, Richards KL, Richardson R, Wimmer V, Yu C, Hill-Yardin EL, Lerche H, Scheffer IE, Berkovic SF, Petrou S.
Axon initial segment dysfunction in a mouse model of genetic epilepsy with febrile seizures plus.
Wimmer VC, Reid CA, Mitchell S, Richards KL, Scaf BB, Leaw BT, Hill EL, Royeck M, Horstmann MT, Cromer BA, Davies PJ, Xu R, Lerche H, Berkovic SF, Beck H, Petrou S.
J Clin Invest 2010;120:2661-71.
Epilepsy and central control of breathing
Stable respiratory activity requires both P/Q-type and N-type voltage-gated Caclium channels.
Koch H, Zanella S ,Elsen GE, Lincoln Smith, Atsushi Doi1, Garcia III A, Wei AD, Xun R. Kirsch S, Gomez CM, Hevner RF and Ramirez JM. (2013).
J Neurosci 2013;33:3633-45
Mitochondrial Ndufs4 deficiency in the vestibular nucleus in a mouse model of Leigh Syndrome leads to fatal breathing dysfunction.
Quintana A, Zanella S, Koch H, Kruse SE, Lee D, Ramirez JM, Palmiter RD.
J Clin Invest 2012;122:2359-68.
Network reconfiguration and neuronal plasticity in rhythm-generating networks.
Koch H, Garcia AJ 3rd, Ramirez JM. (2011).
Int Comp Biol 2011;51:856-68.
Prostaglandin E2 differentially modulates the central control of eupnoea, sighs and gasping in mice.
Koch H, Caughie C, Elsen F, Doi A, Garcia 3rd A, Zanella S and Ramirez JM.
J Physiol 2015;593:305–19.
Zentrum für Neurologie
Hertie-Institut für klinische Hirnforschung
Abteilung Neurologie mit Schwerpunkt Epileptologie
Tel.: +49 (0)7071 29-80466
Fax: +49 (0)7071 29-4488
Dr. Patricia Beck
Tel.: +49 (0)7071 29-80442
Fax: +49 (0)7071 29-4488