48 results on '"Hedrich, Ulrike B. S."'
Search Results
2. KCNC2 variants of uncertain significance are also associated to various forms of epilepsy.
- Author
-
Seiffert, Simone, Pendziwiat, Manuela, Hedrich, Ulrike B. S., Helbig, Ingo, Weber, Yvonne, and Schwarz, Niklas
- Subjects
EPILEPSY ,POTASSIUM channels ,XENOPUS laevis ,VALPROIC acid ,CHANNEL coding - Abstract
Recently, de novo variants in KCNC2, coding for the potassium channel subunit KV3.2, have been described as causative for various forms of epilepsy including genetic generalized epilepsy (GGE) and developmental and epileptic encephalopathy (DEE). Here, we report the functional characteristics of three additional KCNC2 variants of uncertain significance and one variant classified as pathogenic. Electrophysiological studies were performed in Xenopus laevis oocytes. The data presented here support that KCNC2 variants with uncertain significance may also be causative for various forms of epilepsy, as they show changes in the current amplitude and activation and deactivation kinetics of the channel, depending on the variant. In addition, we investigated the effect of valproic acid on KV3.2, as several patients carrying pathogenic variants in the KCNC2 gene achieved significant seizure reduction or seizure freedom with this drug. However, in our electrophysiological investigations, no change on the behavior of KV3.2 channels could be observed, suggesting that the therapeutic effect of VPA may be explained by other mechanisms. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. Loss or gain of function? Effects of ion channel mutations on neuronal firing depend on the neuron type.
- Author
-
Koch, Nils A., Sonnenberg, Lukas, Hedrich, Ulrike B. S., Lauxmann, Stephan, and Benda, Jan
- Subjects
ACTION potentials ,ION channels ,VOLTAGE-gated ion channels ,SPINOCEREBELLAR ataxia ,INDIVIDUALIZED medicine - Abstract
Introduction: Clinically relevant mutations to voltage-gated ion channels, called channelopathies, alter ion channel function, properties of ionic currents, and neuronal firing. The effects of ion channel mutations are routinely assessed and characterized as loss of function (LOF) or gain of function (GOF) at the level of ionic currents. However, emerging personalized medicine approaches based on LOF/GOF characterization have limited therapeutic success. Potential reasons are among others that the translation from this binary characterization to neuronal firing is currently not well-understood--especially when considering different neuronal cell types. In this study, we investigate the impact of neuronal cell type on the firing outcome of ion channel mutations. Methods: To this end, we simulated a diverse collection of single-compartment, conductance-based neuron models that differed in their composition of ionic currents. We systematically analyzed the effects of changes in ion current properties on firing in different neuronal types. Additionally, we simulated the effects of knownmutations in KCNA1 gene encoding the KV1.1 potassiumchannel subtype associated with episodic ataxia type 1 (EA1). Results: These simulations revealed that the outcome of a given change in ion channel properties on neuronal excitability depends on neuron type, i.e., the properties and expression levels of the unaffected ionic currents. Discussion: Consequently, neuron-type specific effects are vital to a full understanding of the effects of channelopathies on neuronal excitability and are an important step toward improving the efficacy and precision of personalized medicine approaches. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. In vitro effects of eslicarbazepine (S‐licarbazepine) as a potential precision therapy on SCN8A variants causing neuropsychiatric disorders.
- Author
-
Bayraktar, Erva, Liu, Yuanyuan, Sonnenberg, Lukas, Hedrich, Ulrike B. S., Sara, Yildirim, Eltokhi, Ahmed, Lyu, Hang, Lerche, Holger, Wuttke, Thomas V., and Lauxmann, Stephan
- Subjects
SODIUM channels ,NEUROBEHAVIORAL disorders ,EPILEPSY ,CHANNEL coding ,BRAIN diseases ,GENETIC code - Abstract
Background and Purpose: Variants in SCN8A, the NaV1.6 channel's coding gene, are characterized by a variety of symptoms, including intractable epileptic seizures, psychomotor delay, progressive cognitive decline, autistic features, ataxia or dystonia. Standard anticonvulsant treatment has a limited impact on the course of disease. Experimental Approach: We investigated the therapeutic potential of eslicarbazepine (S‐licarbazepine; S‐lic), an enhancer of slow inactivation of voltage gated sodium channels, on two variants with biophysical and neuronal gain‐of‐function (G1475R and M1760I) and one variant with biophysical gain‐of‐function but neuronal loss‐of‐function (A1622D) in neuroblastoma cells and in murine primary hippocampal neuron cultures. These three variants cover the broad spectrum of NaV1.6‐associated disease and are linked to representative phenotypes of mild to moderate epilepsy (G1475R), developmental and epileptic encephalopathy (M1760I) and intellectual disability without epilepsy (A1622D). Key Results: Similar to known effects on NaV1.6 wildtype channels, S‐lic predominantly enhances slow inactivation on all tested variants, irrespective of their particular biophysical mechanisms. Beyond that, S‐lic exhibits variant‐specific effects including a partial reversal of pathologically slowed fast inactivation dynamics (A1622D and M1760I) and a trend to reduce enhanced persistent Na+ current by A1622D variant channels. Furthermore, our data in primary transfected neurons reveal that not only variant‐associated hyperexcitability (M1760I and G1475R) but also hypoexcitability (A1622D) can be modulated by S‐lic. Conclusions and Implications: S‐lic has not only substance‐specific effects but also variant‐specific effects. Personalized treatment regimens optimized to achieve such variant‐specific pharmacological modulation may help to reduce adverse side effects and improve the overall therapeutic outcome of SCN8A‐related disease. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
5. KCNA1 gain‐of‐function epileptic encephalopathy treated with 4‐aminopyridine.
- Author
-
Müller, Peter, Takacs, Danielle S., Hedrich, Ulrike B. S., Coorg, Rohini, Masters, Laura, Glinton, Kevin E., Dai, Hongzheng, Cokley, Jon A., Riviello, James J., Lerche, Holger, and Cooper, Edward C.
- Subjects
BRAIN diseases ,PEOPLE with epilepsy ,INDIVIDUALIZED medicine ,EPILEPSY ,PATIENT readmissions - Abstract
Precision medicine for Mendelian epilepsy is rapidly developing. We describe an early infant with severely pharmacoresistant multifocal epilepsy. Exome sequencing revealed the de novo variant p.(Leu296Phe) in the gene KCNA1, encoding the voltage‐gated K+ channel subunit KV1.1. So far, loss‐of‐function variants in KCNA1 have been associated with episodic ataxia type 1 or epilepsy. Functional studies of the mutated subunit in oocytes revealed a gain‐of‐function caused by a hyperpolarizing shift of voltage dependence. Leu296Phe channels are sensitive to block by 4‐aminopyridine. Clinical use of 4‐aminopyridine was associated with reduced seizure burden, enabled simplification of co‐medication and prevented rehospitalization. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
6. Spectrum of Phenotypic, Genetic, and Functional Characteristics in Patients With Epilepsy With KCNC2 Pathogenic Variants
- Author
-
Schwarz, Niklas, Seiffert, Simone, Pendziwiat, Manuela, Rademacher, Annika Verena, Brünger, Tobias, Hedrich, Ulrike B. S., Augustijn, Paul B., Baier, Hartmut, Bayat, Allan, Bisulli, Francesca, Buono, Russell J., Bruria, Ben Zeev, Doyle, Michael G., Guerrini, Renzo, Heimer, Gali, Iacomino, Michele, Kearney, Hugh, Klein, Karl Martin, Kousiappa, Ioanna, Kunz, Wolfram S., Lerche, Holger, Licchetta, Laura, Lohmann, Ebba, Minardi, Raffaella, McDonald, Marie, Montgomery, Sarah, Mulahasanovic, Lejla, Oegema, Renske, Ortal, Barel, Papacostas, Savvas S., Ragona, Francesca, Granata, Tiziana, Reif, Phillip S., Rosenow, Felix, Rothschild, Annick, Scudieri, Paolo, Striano, Pasquale, Tinuper, Paolo, Tanteles, George A., Vetro, Annalisa, Zahnert, Felix, Goldberg, Ethan M., Zara, Federico, Lal, Dennis, May, Patrick, Muhle, Hiltrud, Helbig, Ingo, Weber, Yvonne, Schwarz N., Seiffert S., Pendziwiat M., Rademacher A.V., Brunger T., Hedrich U.B.S., Augustijn P.B., Baier H., Bayat A., Bisulli F., Buono R.J., Bruria B.Z., Doyle M.G., Guerrini R., Heimer G., Iacomino M., Kearney H., Klein K.M., Kousiappa I., Kunz W.S., Lerche H., Licchetta L., Lohmann E., Minardi R., McDonald M., Montgomery S., Mulahasanovic L., Oegema R., Ortal B., Papacostas S.S., Ragona F., Granata T., Reif P.S., Rosenow F., Rothschild A., Scudieri P., Striano P., Tinuper P., Tanteles G.A., Vetro A., Zahnert F., Goldberg E.M., Zara F., Lal D., May P., Muhle H., Helbig I., and Weber Y.
- Subjects
Phenotype ,Epilepsy ,Shaw Potassium Channel ,Epilepsy, Generalized ,Seizure ,Whole Exome Sequencing ,Human - Abstract
Neurology : official journal of the American Academy of Neurology 98(20), e2046-e2059 (2022). doi:10.1212/WNL.0000000000200660, Published by Ovid, [S.l.]
- Published
- 2022
7. Spectrum of Phenotypic, Genetic, and Functional Characteristics in Epilepsy Patients With KCNC2 Pathogenic Variants
- Author
-
Niklas, Schwarz, Simone, Seiffert, Msc, Manuela, Pendziwiat, Annika Verena Rademacher, Tobias, Br¨unger, Phd, Hedrich, Ulrike B. S., Augustijn, Paul B., Hartmut, Baier, Allan, Bayat, Francesca, Bisulli, Phd, Md, Buono, Russell J., Ben Zeev Bruria, Doyle, Michael G., Guerrini, Renzo, Gali, Heimer, Iacomino, Michele, Hugh, Kearney, Karl Martin Klein, Ioanna, Kousiappa, Kunz, Wolfram S., Holger, Lerche, Laura, Licchetta, Ebba, Lohmann, Raffaella, Minardi, Marie, Mcdonald, Sarah, Montgomery, Lejla, Mulahasanovic, Renske, Oegema, Barel, Ortal, Papacostas, Savvas S., Francesca, Ragona, Tiziana, Granata, Reif, Phillip S., Felix, Rosenow, Annick, Rothschild, Scudieri, Paolo, Striano, Pasquale, Paolo, Tinuper, Tanteles, George A., Annalisa, Vetro, Felix, Zahnert, Goldberg, Ethan M., Zara, Federico, Dennis, Lal, Patrick, May, Hiltrud, Muhle, Ingo, Helbig, and and Yvonne Weber
- Subjects
Neurology (clinical) - Abstract
Background:KCNC2 encodes Kv3.2, a member of the Shaw-related (Kv3) voltage-gated potassium channel subfamily, which is important for sustained high-frequency firing and optimized energy efficiency of action potentials in the brain. The objective of this study was to analyse the clinical phenotype, genetic background, and biophysical function of disease-associated Kv3.2 variants.Methods:Individuals with KCNC2 variants detected by exome sequencing were selected for clinical, further genetic, and functional analysis. Cases were referred through clinical and research collaborations. Selected de novo variants were examined electrophysiologically in Xenopus laevis oocytes.Results:We identified novel KCNC2 variants in 18 patients with various forms of epilepsy including genetic generalized epilepsy (GGE), developmental and epileptic encephalopathy (DEE) including early-onset absence epilepsy (EOAE), focal epilepsy (FE), and myoclonic-atonic epilepsy (MAE). 10/18 variants were de novo and 8/18 variants were classified as modifying variants. 8 drug responsive cases became seizure-free using valproic acid as monotherapy or in combination including severe DEE cases. Functional analysis of four variants demonstrated gain-of-function in three severely affected DEE cases and loss-of-function in one case with a milder phenotype (GGE) as the underlying pathomechanisms.Conclusion:These findings implicate KCNC2 as a novel causative gene for epilepsy and emphasize the critical role of KV3.2 in the regulation of brain excitability.
- Published
- 2022
8. Clinical spectrum and genotype-phenotype associations of KCNA2-related encephalopathies
- Author
-
Masnada, Silvia, Hedrich, Ulrike B. S., Gardella, Elena, Schubert, Julian, Kaiwar, Charu, Klee, Eric W., Lanpher, Brendan C., Gavrilova, Ralitza H., Synofzik, Matthis, Bast, Thomas, Gorman, Kathleen, King, Mary D., Allen, Nicholas M., Conroy, Judith, Zeev, Bruria Ben, Tzadok, Michal, Korff, Christian, Dubois, Fanny, Ramsey, Keri, Narayanan, Vinodh, Serratosa, Jose M., Giraldez, Beatriz G., Helbig, Ingo, Marsh, Eric, OʼBrien, Margaret, Bergqvist, Christina A., Binelli, Adrian, Porter, Brenda, Zaeyen, Eduardo, Horovitz, Dafne D., Wolff, Markus, Marjanovic, Dragan, Caglayan, Hande S., Arslan, Mutluay, Pena, Sergio D. J., Sisodiya, Sanjay M., Balestrini, Simona, Syrbe, Steffen, Veggiotti, Pierangelo, Lemke, Johannes R., Møller, Rikke S., Lerche, Holger, and Rubboli, Guido
- Published
- 2017
- Full Text
- View/download PDF
9. Reply
- Author
-
Helbig, Katherine L., Hedrich, Ulrike B. S., Scheffer, Ingrid E., Helbig, Ingo, Lerche, Holger, and Lemke, Johannes R.
- Published
- 2017
- Full Text
- View/download PDF
10. Predicting functional effects of ion channel variants using new phenotypic machine learning methods.
- Author
-
Boßelmann, Christian Malte, Hedrich, Ulrike B. S., Lerche, Holger, and Pfeifer, Nico
- Subjects
- *
VOLTAGE-gated ion channels , *ION channels , *MACHINE learning , *SUPERVISED learning , *HUMAN phenotype , *PHENOTYPES , *AMINO acid sequence - Abstract
Missense variants in genes encoding ion channels are associated with a spectrum of severe diseases. Variant effects on biophysical function correlate with clinical features and can be categorized as gain- or loss-of-function. This information enables a timely diagnosis, facilitates precision therapy, and guides prognosis. Functional characterization presents a bottleneck in translational medicine. Machine learning models may be able to rapidly generate supporting evidence by predicting variant functional effects. Here, we describe a multi-task multi-kernel learning framework capable of harmonizing functional results and structural information with clinical phenotypes. This novel approach extends the human phenotype ontology towards kernel-based supervised machine learning. Our gain- or loss-of-function classifier achieves high performance (mean accuracy 0.853 SD 0.016, mean AU-ROC 0.912 SD 0.025), outperforming both conventional baseline and state-of-the-art methods. Performance is robust across different phenotypic similarity measures and largely insensitive to phenotypic noise or sparsity. Localized multi-kernel learning offered biological insight and interpretability by highlighting channels with implicit genotype-phenotype correlations or latent task similarity for downstream analysis. Author summary: Genetic variants can impact the function of voltage-gated ion channels, which are transmembrane channels that are important for the electrical signalling of neurons. Individuals affected by these variants may have severe neurological or cardiac disease. Knowing the functional effects of variants can help us improve the diagnosis and clinical care for these individuals, and may also enable precision medicine aimed at correcting channel function. Machine learning methods are capable of predicting these functional effects, but previous models have only included information from protein sequence and structure. Here, we have developed a novel algorithm that can integrate clinical information by using the Human Phenotype Ontology (HPO), a standardized vocabulary of phenotypic features encountered in human disease. These different sources of information are used to train a multi-kernel support-vector machine. Our results suggest that this model is robust, interpretable, and more accurate than previous methods. Variant functional effect prediction engines will be useful tools for clinical geneticists, neurologists and biophysicists. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
11. Heterozygous variants in KCNC2 cause a broad spectrum of epilepsy phenotypes associated with characteristic functional alterations 2021.05.21.21257099
- Author
-
Schwarz, Niklas, Seiffert, Simone, Pendziwiat, Manuela, Rademacher, Annika, Brünger, Tobias, Hedrich, Ulrike B. S., Augustijn, Paul B., Baier, Hartmut, Bayat, Allan, Bisulli, Francesca, Buono, Russell J., Bruria, Ben Zeev, Doyle, Michael G., Guerrini, Renzo, Heimer, Gali, Iacomino, Michele, Kearney, Hugh, Klein, Karl Martin, Kousiappa, Ioanna, Kunz, Wolfram S., Lerche, Holger, Licchetta, Laura, Lohmann, Ebba, Minardi, Raffaella, McDonald, Marie, Montgomery, Sarah, Mulahasanovic, Lejla, Oegema, Renske, Ortal, Barel, Papacostas, Savvas S., Ragona, Francesca, Granata, Tiziana, Reif, Philipp S., Rosenow, Felix, Rothschild, Annick, Scudieri, Paolo, Striano, Pasquale, Tinuper, Paolo, Tanteles, George A., Vetro, Annalisa, Zahnert, Felix, Zara, Federico, Lal, Dennis, May, Patrick, Muhle, Hiltrud, Helbig, Ingo, Weber, Yvonne, BMBF Treat-ION grant (01GM1907). [sponsor], and Luxembourg Centre for Systems Biomedicine (LCSB): Bioinformatics Core (R. Schneider Group) [research center]
- Subjects
KCNC2 ,Neurologie [D14] [Sciences de la santé humaine] ,Neurology [D14] [Human health sciences] ,epilepsy ,Genetics & genetic processes [F10] [Life sciences] ,Génétique & processus génétiques [F10] [Sciences du vivant] ,potassium channel - Abstract
Background KCNC2 encodes a member of the shaw-related voltage-gated potassium channel family (KV3.2), which are important for sustained high-frequency firing and optimized energy efficiency of action potentials in the brain.Methods Individuals with KCNC2 variants detected by exome sequencing were selected for clinical, further genetic and functional analysis. The cases were referred through clinical and research collaborations in our study. Four de novo variants were examined electrophysiologically in Xenopus laevis oocytes.Results We identified novel KCNC2 variants in 27 patients with various forms of epilepsy. Functional analysis demonstrated gain-of-function in severe and loss-of-function in milder phenotypes as the underlying pathomechanisms with specific response to valproic acid.Conclusion These findings implicate KCNC2 as a novel causative gene for epilepsy emphasizing the critical role of KV3.2 in the regulation of brain excitability with an interesting genotype-phenotype correlation and a potential concept for precision medicine.
- Published
- 2021
12. Genotype-phenotype correlations in SCN8A-related disorders reveal prognostic and therapeutic implications
- Author
-
Johannesen, Katrine M., Liu, Yuanyuan, Gjerulfsen, Cathrine E., Koko, Mahmoud, Sonnenberg, Lukas, Schubert, Julian, Fenger, Christina D., Eltokhi, Ahmed, Rannap, Maert, Koch, Nils A., Lauxmann, Stephan, Krüger, Johanna, Kegele, Josua, Canafoglia, Laura, Franceschetti, Silvana, Mayer, Thomas, Rebstock, Johannes, Zacher, Pia, Ruf, Susanne, Alber, Michael, Sterbova, Katalin, Lassuthová, Petra, Vlckova, Marketa, Lemke, Johannes R., Krey, Ilona, Heine, Constanze, Wieczorek, Dagmar, Kroell-Seger, Judith, Lund, Caroline, Klein, Karl Martin, Au, P. Y. Billie, Rho, Jong M., Ho, Alice W., Masnada, Silvia, Veggiotti, Pierangelo, Giordano, Lucio, Accorsi, Patrizia, Hoei-Hansen, Christina E., Striano, Pasquale, Zara, Federico, Verhelst, Helene, S.Verhoeven, Judith, van der Zwaag, Bert, Harder, Aster V. E., Brilstra, Eva, Pendziwiat, Manuela, Lebon, Sebastian, Vaccarezza, Maria, Le, Ngoc Minh, Christensen, Jakob, Schmidt-Petersen, Mette U., Grønborg, Sabine, Scherer, Stephen W., Howe, Jennifer, Fazeli, Walid, Howell, Katherine B., Leventer, Richard, Stutterd, Chloe, Walsh, Sonja, Gerard, Marion, Gerard, Bénédicte, Matricardi, Sara, Bonardi, Claudia M., Sartori, Stefano, Berger, Andrea, Hoffman-Zacharska, Dorota, Mastrangelo, Massimo, Darra, Francesca, Vøllo, Arve, Motazacker, M. Mahdi, Lakeman, Phillis, Nizon, Mathilde, Betzler, Cornelia, Altuzarra, Cecilia, Caume, Roseline, Roubertie, Agathe, Gélisse, Philippe, Marini, Carla, Guerrini, Renzo, Bilan, Frederic, Tibussek, Daniel, Koch-Hogrebe, Margarete, Perry, M. Scott, Ichikawa, Shoji, Dadali, Elena, Sharkov, Artem, Mishina, Irina, Abramov, Mikhail, Kanivets, Ilya, Korostelev, Sergey, Kutsev, Sergey, Wain, Karen E., Eisenhauer, Nancy, Wagner, Monisa, Savatt, Juliann M., Müller-Schlüter, Karen, Bassan, Haim, Borovikov, Artem, Nassogne, Marie-Cecile, Destrée, Anne, Schoonjans, An-Sofie, Meuwissen, Marije, Buzatu, Marga, Jansen, Anna, Scalais, Emmanuel, Srivastava, Siddharth, Tan, Wen-Hann, Olson, Heather E., Loddenkemper, Tobias, Poduri, Annapurna, Helbig, Katherine L., Helbig, Ingo, Fitzgerald, Mark P., Goldberg, Ethan M., Roser, Timo, Borggraefe, Ingo, Brünger, Tobias, May, Patrick, Lal, Dennis, Lederer, Damien, Rubboli, Guido, Lesca, Gaetan, Hedrich, Ulrike B. S., Benda, Jan, Gardella, Elena, Lerche, Holger, Møller, Rikke S., and Luxembourg Centre for Systems Biomedicine (LCSB): Bioinformatics Core (R. Schneider Group) [research center]
- Subjects
Genetics & genetic processes [F10] [Life sciences] ,Génétique & processus génétiques [F10] [Sciences du vivant] - Abstract
We report detailed functional analyses and genotype-phenotype correlations in 433 individuals carrying disease-causing variants in SCN8A, encoding the voltage-gated Na+ channel NaV1.6. Five different clinical subgroups could be identified: 1) Benign familial infantile epilepsy (BFIE) (n=17, normal cognition, treatable seizures), 2) intermediate epilepsy (n=36, mild ID, partially pharmacoresponsive), 3) developmental and epileptic encephalopathy (DEE, n=191, severe ID, majority pharmacoresistant), 4) generalized epilepsy (n=21, mild to moderate ID, frequently with absence seizures), and 5) affected individuals without epilepsy (n=25, mild to moderate ID). Groups 1-3 presented with early-onset (median: four months) focal or multifocal seizures and epileptic discharges, whereas the onset of seizures in group 4 was later (median: 39 months) with generalized epileptic discharges. The epilepsy was not classifiable in 143 individuals. We performed functional studies expressing missense variants in ND7/23 neuroblastoma cells and primary neuronal cultures using recombinant tetrodotoxin insensitive human NaV1.6 channels and whole-cell patch clamping. Two variants causing DEE showed a strong gain-of-function (GOF, hyperpolarising shift of steady-state activation, strongly increased neuronal firing rate), and one variant causing BFIE or intermediate epilepsy showed a mild GOF (defective fast inactivation, less increased firing). In contrast, all three variants causing generalized epilepsy induced a loss-of-function (LOF, reduced current amplitudes, depolarising shift of steady-state activation, reduced neuronal firing). Including previous studies, functional effects were known for 165 individuals. All 133 individuals carrying GOF variants had either focal (76, groups 1-3), or unclassifiable epilepsy (37), whereas 32 with LOF variants had either generalized (14), no (11) or unclassifiable (5) epilepsy; only two had DEE. Computational modeling in the GOF group revealed a significant correlation between the severity of the electrophysiological and clinical phenotypes. GOF variant carriers responded significantly better to sodium channel blockers (SCBs) than to other anti-seizure medications, and the same applied for all individuals of groups 1-3.In conclusion, our data reveal clear genotype-phenotype correlations between age at seizure onset, type of epilepsy and gain- or loss-of-function effects of SCN8A variants. Generalized epilepsy with absence seizures is the main epilepsy phenotype of LOF variant carriers and the extent of the electrophysiological dysfunction of the GOF variants is a main determinant of the severity of the clinical phenotype in focal epilepsies. Our pharmacological data indicate that SCBs present a therapeutic treatment option in early onset SCN8A-related focal epilepsy.
- Published
- 2021
13. Dravet Variant SCN1A$^{A1783V}$ Impairs Interneuron Firing Predominantly by Altered Channel Activation
- Author
-
Layer, Nikolas, Sonnenberg, Lukas, Pardo González, Emilio, Benda, Jan, Hedrich, Ulrike B. S., Lerche, Holger, Koch, Henner, and Wuttke, Thomas V.
- Abstract
Frontiers in cellular neuroscience 15, 754530 (2021). doi:10.3389/fncel.2021.754530 special issue: "Cellular Neurophysiology / Editors: Enrico Cherubini, Arianna Maffei, Giorgio Aicardi, Joseph P. Albanesi", Published by Frontiers Research Foundation, Lausanne
- Published
- 2021
- Full Text
- View/download PDF
14. An SCN2A mutation in a family with infantile seizures from Madagascar reveals an increased subthreshold Na+ current
- Author
-
Lauxmann, Stephan, Boutry-Kryza, Nadia, Rivier, Clotilde, Mueller, Stephan, Hedrich, Ulrike B. S., Maljevic, Snezana, Szepetowski, Pierre, Lerche, Holger, and Lesca, Gaetan
- Published
- 2013
- Full Text
- View/download PDF
15. KCND2 variants associated with global developmental delay differentially impair Kv4.2 channel gating.
- Author
-
Zhang, Yongqiang, Tachtsidis, Georgios, Schob, Claudia, Koko, Mahmoud, Hedrich, Ulrike B S, Lerche, Holger, Lemke, Johannes R, Haeringen, Arie van, Ruivenkamp, Claudia, Prescott, Trine, Tveten, Kristian, Gerstner, Thorsten, Pruniski, Brianna, DiTroia, Stephanie, VanNoy, Grace E, Rehm, Heidi L, McLaughlin, Heather, Bolz, Hanno J, Zechner, Ulrich, and Bryant, Emily
- Published
- 2021
- Full Text
- View/download PDF
16. Hyperexcitable interneurons trigger cortical spreading depression in an Scn1a migraine model.
- Author
-
Auffenberg, Eva, Hedrich, Ulrike B. S., Barbieri, Raffaella, Miely, Daniela, Groschup, Bernhard, Wuttke, Thomas V., Vogel, Niklas, Lührs, Philipp, Zanardi, Ilaria, Bertelli, Sara, Spielmann, Nadine, Gailus-Durner, Valerie, Fuchs, Helmut, de Angelis, Martin Hrabě, Pusch, Michael, Dichgans, Martin, Lerche, Holger, Gavazzo, Paola, Plesnila, Nikolaus, and Freilinger, Tobias
- Abstract
Cortical spreading depression (CSD), a wave of depolarization followed by depression of cortical activity, is a pathophysiological process implicated in migraine with aura and various other brain pathologies, such as ischemic stroke and traumatic brain injury. To gain insight into the pathophysiology of CSD, we generated a mouse model for a severe monogenic subtype of migraine with aura, familial hemiplegic migraine type 3 (FHM3). FHM3 is caused by mutations in SCN1A, encoding the voltage-gated Na+ channel NaV1.1 predominantly expressed in inhibitory interneurons. Homozygous Scn1aL1649Q knock-in mice died prematurely, whereas heterozygous mice had a normal lifespan. Heterozygous Scn1aL1649Q knock-in mice compared with WT mice displayed a significantly enhanced susceptibility to CSD. We found L1649Q to cause a gain-of-function effect with an impaired Na+ -channel inactivation and increased ramp Na+ currents leading to hyperactivity of fast-spiking inhibitory interneurons. Brain slice recordings using K+ -sensitive electrodes revealed an increase in extracellular K+ in the early phase of CSD in heterozygous mice, likely representing the mechanistic link between interneuron hyperactivity and CSD initiation. The neuronal phenotype and premature death of homozygous Scn1aL1649Q knock-in mice was partially rescued by GS967, a blocker of persistent Na+ currents. Collectively, our findings identify interneuron hyperactivity as a mechanism to trigger CSD. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
17. Dravet Variant SCN1A A 1783 V Impairs Interneuron Firing Predominantly by Altered Channel Activation.
- Author
-
Layer, Nikolas, Sonnenberg, Lukas, Pardo González, Emilio, Benda, Jan, Hedrich, Ulrike B. S., Lerche, Holger, Koch, Henner, and Wuttke, Thomas V.
- Subjects
MISSENSE mutation ,SODIUM channels ,LABORATORY mice ,GENETIC variation ,INTERNEURONS ,PYRAMIDAL neurons ,BRAIN diseases ,ANIMAL disease models - Abstract
Dravet syndrome (DS) is a developmental epileptic encephalopathy mainly caused by functional Na
V 1.1 haploinsufficiency in inhibitory interneurons. Recently, a new conditional mouse model expressing the recurrent human p.(Ala1783Val) missense variant has become available. In this study, we provided an electrophysiological characterization of this variant in tsA201 cells, revealing both altered voltage-dependence of activation and slow inactivation without reduced sodium peak current density. Based on these data, simulated interneuron (IN) firing properties in a conductance-based single-compartment model suggested surprisingly similar firing deficits for NaV 1.1A1783V and full haploinsufficiency as caused by heterozygous truncation variants. Impaired NaV 1.1A1783V channel activation was predicted to have a significantly larger impact on channel function than altered slow inactivation and is therefore proposed as the main mechanism underlying IN dysfunction. The computational model was validated in cortical organotypic slice cultures derived from conditional Scn1aA 1783 V mice. Pan-neuronal activation of the p.Ala1783V in vitro confirmed a predicted IN firing deficit and revealed an accompanying reduction of interneuronal input resistance while demonstrating normal excitability of pyramidal neurons. Altered input resistance was fed back into the model for further refinement. Taken together these data demonstrate that primary loss of function (LOF) gating properties accompanied by altered membrane characteristics may match effects of full haploinsufficiency on the neuronal level despite maintaining physiological peak current density, thereby causing DS. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
18. Regulation of motor pattern frequency by reversals in proprioceptive feedback
- Author
-
Smarandache, Carmen R., Daur, Nelly, Hedrich, Ulrike B. S., and Stein, Wolfgang
- Published
- 2008
19. Kultivierung von humanem kortikalem Resektionsgewebe nach epilepsiechirurgischen Eingriffen - Implementierung eines Modellsystems zur Untersuchung pathophysiologischer Mechanismen von ZNS Erkrankungen
- Author
-
Wuttke, Thomas, Schwarz, Niklas, Hedrich, Ulrike B. S., Honegger, Jürgen B., Lerche, Holger, and Koch, Henner
- Subjects
ddc: 610 ,610 Medical sciences ,Medicine - Abstract
Objective: Investigation of pathophysiological mechanisms of human disease affecting the CNS, such as epilepsy or neurodegenerative disorders, mostly relies on studies based on human tissue obtained post mortem or by biopsy/surgery and on studies using animal models, cell culture or heterologous[for full text, please go to the a.m. URL], 70. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Skandinavischen Gesellschaft für Neurochirurgie
- Published
- 2019
- Full Text
- View/download PDF
20. KCNC1-related disorders: New de novo variants expand the phenotypic spectrum
- Author
-
Park, Joohyun, Koko, Mahmoud, Hedrich, Ulrike B. S., Hermann, Andreas, Cremer, Kirsten, Haberlandt, Edda, Grimmel, Mona, Alhaddad, Bader, Beck‐Woedl, Stefanie, Harrer, Merle, Karall, Daniela, Kingelhoefer, Lisa, Tzschach, Andreas, Matthies, Lars C., Strom, Tim M., Ringelstein, Erich Bernd, Sturm, Marc, Engels, Hartmut, Wolff, Markus, Lerche, Holger, and Haack, Tobias B.
- Subjects
Male ,Mutation, Missense ,Neurosciences. Biological psychiatry. Neuropsychiatry ,Brief Communication ,Xenopus laevis ,Seizures ,physiology [Shaw Potassium Channels] ,Intellectual Disability ,Animals ,Humans ,ddc:610 ,RC346-429 ,Child ,Genetic Association Studies ,genetics [Shaw Potassium Channels] ,genetics [Ataxia] ,Myoclonic Epilepsies, Progressive ,genetics [Seizures] ,Shaw Potassium Channels ,Codon, Nonsense ,Ataxia ,Neurology. Diseases of the nervous system ,genetics [Intellectual Disability] ,Brief Communications ,RC321-571 - Abstract
A recurrent de novo missense variant in KCNC1, encoding a voltage‐gated potassium channel expressed in inhibitory neurons, causes progressive myoclonus epilepsy and ataxia, and a nonsense variant is associated with intellectual disability. We identified three new de novo missense variants in KCNC1 in five unrelated individuals causing different phenotypes featuring either isolated nonprogressive myoclonus (p.Cys208Tyr), intellectual disability (p.Thr399Met), or epilepsy with myoclonic, absence and generalized tonic‐clonic seizures, ataxia, and developmental delay (p.Ala421Val, three patients). Functional analyses demonstrated no measurable currents for all identified variants and dominant‐negative effects for p.Thr399Met and p.Ala421Val predicting neuronal disinhibition as the underlying disease mechanism.
- Published
- 2019
21. Motor pattern selection by nitric oxide in the stomatogastric nervous system of the crab
- Author
-
Stein, Wolfgang, Eberle, Christina C., and Hedrich, Ulrike B. S.
- Published
- 2005
22. Therapeutic Potential of Sodium Channel Blockers as a Targeted Therapy Approach in KCNA1 -Associated Episodic Ataxia and a Comprehensive Review of the Literature.
- Author
-
Lauxmann, Stephan, Sonnenberg, Lukas, Koch, Nils A., Bosselmann, Christian, Winter, Natalie, Schwarz, Niklas, Wuttke, Thomas V., Hedrich, Ulrike B. S., Liu, Yuanyuan, Lerche, Holger, Benda, Jan, and Kegele, Josua
- Subjects
SODIUM channel blockers ,SPINOCEREBELLAR ataxia ,CHANNEL coding ,TREMOR ,DRUG repositioning ,ATAXIA - Abstract
Introduction: Among genetic paroxysmal movement disorders, variants in ion channel coding genes constitute a major subgroup. Loss-of-function (LOF) variants in KCNA1 , the gene coding for K
V 1.1 channels, are associated with episodic ataxia type 1 (EA1), characterized by seconds to minutes-lasting attacks including gait incoordination, limb ataxia, truncal instability, dysarthria, nystagmus, tremor, and occasionally seizures, but also persistent neuromuscular symptoms like myokymia or neuromyotonia. Standard treatment has not yet been developed, and different treatment efforts need to be systematically evaluated. Objective and Methods: Personalized therapeutic regimens tailored to disease-causing pathophysiological mechanisms may offer the specificity required to overcome limitations in therapy. Toward this aim, we (i) reviewed all available clinical reports on treatment response and functional consequences of KCNA1 variants causing EA1, (ii) examined the potential effects on neuronal excitability of all variants using a single compartment conductance-based model and set out to assess the potential of two sodium channel blockers (SCBs: carbamazepine and riluzole) to restore the identified underlying pathophysiological effects of KV 1.1 channels, and (iii) provide a comprehensive review of the literature considering all types of episodic ataxia. Results: Reviewing the treatment efforts of EA1 patients revealed moderate response to acetazolamide and exhibited the strength of SCBs, especially carbamazepine, in the treatment of EA1 patients. Biophysical dysfunction of KV 1.1 channels is typically based on depolarizing shifts of steady-state activation, leading to an LOF of KCNA1 variant channels. Our model predicts a lowered rheobase and an increase of the firing rate on a neuronal level. The estimated concentration dependent effects of carbamazepine and riluzole could partially restore the altered gating properties of dysfunctional variant channels. Conclusion: These data strengthen the potential of SCBs to contribute to functional compensation of dysfunctional KV 1.1 channels. We propose riluzole as a new drug repurposing candidate and highlight the role of personalized approaches to develop standard care for EA1 patients. These results could have implications for clinical practice in future and highlight the need for the development of individualized and targeted therapies for episodic ataxia and genetic paroxysmal disorders in general. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
23. 4-Aminopyridine is a promising treatment option for patients with gain-of-function KCNA2-encephalopathy.
- Author
-
Hedrich, Ulrike B. S., Lauxmann, Stephan, Wolff, Markus, Synofzik, Matthis, Bast, Thomas, Binelli, Adrian, Serratosa, José M., Martínez-Ulloa, Pedro, Allen, Nicholas M., King, Mary D., Gorman, Kathleen M., Zeev, Bruria Ben, Tzadok, Michal, Wong-Kisiel, Lily, Marjanovic, Dragan, Rubboli, Guido, Sisodiya, Sanjay M., Lutz, Florian, Ashraf, Harshad Pannikkaveettil, and Torge, Kirsten
- Subjects
POTASSIUM channels ,POTASSIUM antagonists ,PHYSICIANS ,SEIZURES (Medicine) ,GAIN-of-function mutations ,CEREBELLAR ataxia ,VAGUS nerve - Abstract
Targeting the K
+ ey current: Gain-of-function (GOF) mutations in the potassium channel Kv1.2 cause a subtype of developmental KCNA2-encephalopathy, characterized by the occurrence of seizures, cerebellar ataxia, and intellectual disabilities. The available treatments are mostly ineffective. Here, Hedrich et al. showed that the potassium channel blocker 4-aminopyridine (4-AP) corrected electrophysiological abnormalities in neurons in vitro. 4-AP was effective in reducing symptoms in 9 of 11 patients carrying GOF Kv1.2 mutations. Seizure reduction and improvements in movements and cognition were reported for the majority of the treated patients, without causing severe side effects. The results suggest that blocking potassium channels could be an effective approach for treating patients with GOF in Kv1.2. Developmental and epileptic encephalopathies are devastating disorders characterized by epilepsy, intellectual disability, and other neuropsychiatric symptoms, for which available treatments are largely ineffective. Following a precision medicine approach, we show for KCNA2-encephalopathy that the K+ channel blocker 4-aminopyridine can antagonize gain-of-function defects caused by variants in the KV 1.2 subunit in vitro, by reducing current amplitudes and negative shifts of steady-state activation and increasing the firing rate of transfected neurons. In n-of-1 trials carried out in nine different centers, 9 of 11 patients carrying such variants benefitted from treatment with 4-aminopyridine. All six patients experiencing daily absence, myoclonic, or atonic seizures became seizure-free (except some remaining provoked seizures). Two of six patients experiencing generalized tonic-clonic seizures showed marked improvement, three showed no effect, and one worsening. Nine patients showed improved gait, ataxia, alertness, cognition, or speech. 4-Aminopyridine was well tolerated up to 2.6 mg/kg per day. We suggest 4-aminopyridine as a promising tailored treatment in KCNA2-(gain-of-function)–encephalopathy and provide an online tool assisting physicians to select patients with gain-of-function mutations suited to this treatment. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
24. De novo loss- or gain-of-function mutations in KCNA2 cause epileptic encephalopathy
- Author
-
Syrbe, Steffen, Hedrich, Ulrike B S, Arslan, Mutluay, Serratosa, José M, Nothnagel, Michael, May, Patrick, Krause, Roland, Löffler, Heidrun, Detert, Katja, Dorn, Thomas, Vogt, Heinrich, Krämer, Günter, Riesch, Erik, Schöls, Ludger, Mullis, Primus E, Linnankivi, Tarja, Lehesjoki, Anna-Elina, Sterbova, Katalin, Craiu, Dana C, Hoffman-Zacharska, Dorota, Korff, Christian M, Weber, Yvonne G, Steinlin, Maja, Djémié, Tania, Gallati, Sabina, Bertsche, Astrid, Bernhard, Matthias K, Merkenschlager, Andreas, Kiess, Wieland, consortium, EuroEPINOMICS RES, Gonzalez, Michael, Züchner, Stephan, Palotie, Aarno, Suls, Arvid, Müller, Stephan, De Jonghe, Peter, Helbig, Ingo, Biskup, Saskia, Wolff, Markus, Maljevic, Snezana, Schüle, Rebecca, Sisodiya, Sanjay M, Weckhuysen, Sarah, Lerche, Holger, Lemke, Johannes R, Møller, Rikke S, Balling, Rudi, Barisic, Nina, Baulac, Stéphanie, Caglayan, Hande S, Depienne, Christel, Gormley, Padhraig, Guerrini, Renzo, Maher, Bridget, Hjalgrim, Helle, Jähn, Johanna, Klein, Karl Martin, Koeleman, Bobby P C, Komarek, Vladimir, LeGuern, Eric, Hernandez-Hernandez, Laura, Marini, Carla, Muhle, Hiltrud, Pal, Deb, Rosenow, Felix, Selmer, Kaja, Synofzik, Matthis, Stephani, Ulrich, Striano, Pasquale, Talvik, Tiina, von Spiczak, Sarah, Zara, Federico, and EuroEPINOMICS RES Consortium
- Subjects
Adult ,Male ,Ataxia ,genetics [Epilepsy] ,genetics [Kv1.2 Potassium Channel] ,Biology ,medicine.disease_cause ,Bioinformatics ,Infantile ,Epilepsy/genetics ,Article ,Spasms ,Cohort Studies ,Epilepsy ,Young Adult ,Spasms, Infantile/genetics ,ddc:570 ,Amino Acid Sequence ,Child ,Child, Preschool ,Female ,Genetic Predisposition to Disease ,Humans ,Infant ,Kv1.2 Potassium Channel ,Pedigree ,Spasms, Infantile ,Mutation ,Genetics ,Intellectual disability ,medicine ,KCNA2 protein, human ,Preschool ,Loss function ,Kv1.2 Potassium Channel/genetics ,ddc:618 ,Genetic heterogeneity ,Seizure types ,genetics [Spasms, Infantile] ,medicine.disease ,Myoclonic epilepsy ,Human medicine ,medicine.symptom - Abstract
Epileptic encephalopathies are a phenotypically and genetically heterogeneous group of severe epilepsies accompanied by intellectual disability and other neurodevelopmental features(1-6). Using next-generation sequencing, we identified four different de novo mutations in KCNA2, encoding the potassium channel K(V)1.2, in six isolated patients with epileptic encephalopathy (one mutation recurred three times independently). Four individuals presented with febrile and multiple afebrile, often focal seizure types, multifocal epileptiform discharges strongly activated by sleep, mild to moderate intellectual disability, delayed speech development and sometimes ataxia. Functional studies of the two mutations associated with this phenotype showed almost complete loss of function with a dominant-negative effect. Two further individuals presented with a different and more severe epileptic encephalopathy phenotype. They carried mutations inducing a drastic gain-of-function effect leading to permanently open channels. These results establish KCNA2 as a new gene involved in human neurodevelopmental disorders through two different mechanisms, predicting either hyperexcitability or electrical silencing of K(V)1.2-expressing neurons.
- Published
- 2015
25. SCN2A channelopathies: Mechanisms and models.
- Author
-
Hedrich, Ulrike B. S., Lauxmann, Stephan, and Lerche, Holger
- Subjects
- *
SODIUM channels , *BRUGADA syndrome , *INTELLECTUAL disabilities , *FUNCTIONAL analysis , *SEIZURES (Medicine) , *PARTIAL epilepsy , *AUTISM - Abstract
Summary: Variants in the SCN2A gene, encoding the voltage‐gated sodium channel NaV1.2, cause a variety of neuropsychiatric syndromes with different severity ranging from self‐limiting epilepsies with early onset to developmental and epileptic encephalopathy with early or late onset and intellectual disability (ID), as well as ID or autism without seizures. Functional analysis of channel defects demonstrated a genotype‐phenotype correlation and suggested effective treatment options for one group of affected patients carrying gain‐of‐function variants. Here, we sum up the functional mechanisms underlying different phenotypes of patients with SCN2A channelopathies and present currently available models that can help in understanding SCN2A‐related disorders. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
26. SCN2A channelopathies: Mechanisms and models.
- Author
-
Hedrich, Ulrike B. S., Lauxmann, Stephan, and Lerche, Holger
- Subjects
- *
SODIUM channels , *INTELLECTUAL disabilities , *FUNCTIONAL analysis , *SEIZURES (Medicine) , *BRUGADA syndrome , *AUTISM - Abstract
Summary: Variants in the SCN2A gene, encoding the voltage‐gated sodium channel NaV1.2, cause a variety of neuropsychiatric syndromes with different severity ranging from self‐limiting epilepsies with early onset to developmental and epileptic encephalopathy with early or late onset and intellectual disability (ID), as well as ID or autism without seizures. Functional analysis of channel defects demonstrated a genotype‐phenotype correlation and suggested effective treatment options for one group of affected patients carrying gain‐of‐function variants. Here, we sum up the functional mechanisms underlying different phenotypes of patients with SCN2A channelopathies and present currently available models that can help in understanding SCN2A‐related disorders. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
27. Genetic and phenotypic heterogeneity suggest therapeutic implications in SCN2A-related disorders.
- Author
-
Wolff, Markus, Johannesen, Katrine M, Hedrich, Ulrike B S, Masnada, Silvia, Rubboli, Guido, Gardella, Elena, Lesca, Gaetan, Ville, Dorothée, Milh, Mathieu, Villard, Laurent, Afenjar, Alexandra, Chantot-Bastaraud, Sandra, Mignot, Cyril, Lardennois, Caroline, Nava, Caroline, Schwarz, Niklas, Gérard, Marion, Perrin, Laurence, Doummar, Diane, and Auvin, Stéphane
- Abstract
Mutations in SCN2A, a gene encoding the voltage-gated sodium channel Nav1.2, have been associated with a spectrum of epilepsies and neurodevelopmental disorders. Here, we report the phenotypes of 71 patients and review 130 previously reported patients. We found that (i) encephalopathies with infantile/childhood onset epilepsies (≥3 months of age) occur almost as often as those with an early infantile onset (<3 months), and are thus more frequent than previously reported; (ii) distinct phenotypes can be seen within the late onset group, including myoclonic-atonic epilepsy (two patients), Lennox-Gastaut not emerging from West syndrome (two patients), and focal epilepsies with an electrical status epilepticus during slow sleep-like EEG pattern (six patients); and (iii) West syndrome constitutes a common phenotype with a major recurring mutation (p.Arg853Gln: two new and four previously reported children). Other known phenotypes include Ohtahara syndrome, epilepsy of infancy with migrating focal seizures, and intellectual disability or autism without epilepsy. To assess the response to antiepileptic therapy, we retrospectively reviewed the treatment regimen and the course of the epilepsy in 66 patients for which well-documented medical information was available. We find that the use of sodium channel blockers was often associated with clinically relevant seizure reduction or seizure freedom in children with early infantile epilepsies (<3 months), whereas other antiepileptic drugs were less effective. In contrast, sodium channel blockers were rarely effective in epilepsies with later onset (≥3 months) and sometimes induced seizure worsening. Regarding the genetic findings, truncating mutations were exclusively seen in patients with late onset epilepsies and lack of response to sodium channel blockers. Functional characterization of four selected missense mutations using whole cell patch-clamping in tsA201 cells-together with data from the literature-suggest that mutations associated with early infantile epilepsy result in increased sodium channel activity with gain-of-function, characterized by slowing of fast inactivation, acceleration of its recovery or increased persistent sodium current. Further, a good response to sodium channel blockers clinically was found to be associated with a relatively small gain-of-function. In contrast, mutations in patients with late-onset forms and an insufficient response to sodium channel blockers were associated with loss-of-function effects, including a depolarizing shift of voltage-dependent activation or a hyperpolarizing shift of channel availability (steady-state inactivation). Our clinical and experimental data suggest a correlation between age at disease onset, response to sodium channel blockers and the functional properties of mutations in children with SCN2A-related epilepsy. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
28. Impaired Action Potential Initiation in GAB Aergic Interneurons Causes Hyperexcitable Networks in an Epileptic Mouse Model Carrying a Human NaV1.1 Mutation.
- Author
-
Hedrich, Ulrike B. S., Liautard, Camille, Kirschenbaum, Daniel, Pofahl, Martin, Lavigne, Jennifer, Yuanyuan Liu, Theiss, Stephan, Slotta, Johannes, Escayg, Andrew, Dihné, Marcel, Beck, Heinz, Mantegazza, Massimo, and Lerche, Holger
- Subjects
- *
ACTION potentials , *GABA agents , *INTERNEURONS , *PEOPLE with epilepsy , *GENETIC mutation , *SODIUM ions , *LABORATORY mice - Abstract
Mutations in SCN1A and other ion channel genes can cause different epileptic phenotypes, but the precise mechanisms underlying the development of hyperexcitable networks are largely unknown. Here, we present a multisystem analysis of an SCN1A mouse model carrying the Nav1.1-R1648H mutation, which causes febrile seizures and epilepsy in humans. We found a ubiquitous hypoexcitability of interneurons in thalamus, cortex, and hippocampus, without detectable changes in excitatory neurons. Interestingly, somatic Na+ channels in interneurons and persistent Na+ currents were not significantly changed. Instead, the key mechanism of interneuron dysfunction was a deficit of action potential initiation at the axon initial segment that was identified by analyzing action potential firing. This deficit increased with the duration of firing periods, suggesting that increased slow inactivation, as recorded for recombinant mutated channels, could play an important role. The deficit in interneuron firing caused reduced action potential-driven inhibition of excitatory neurons as revealed by less frequent spontaneous but not miniature IPSCs. Multiple approaches indicated increased spontaneous thalamocortical and hippocampal network activity in mutant mice, as follows: (1) more synchronous and higher-frequency firing was recorded in primary neuronal cultures plated on multielectrode arrays; (2) thalamocortical slices examined by field potential recordings revealed spontaneous activities and pathological high-frequency oscillations; and (3) multineuron Ca2+ imaging in hippocampal slices showed increased spontaneous neuronal activity. Thus, an interneuron-specific generalized defect in action potential initiation causes multisystem disinhibition and network hyperexcitability, which can well explain the occurrence of seizures in the studied mouse model and in patients carrying this mutation. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
29. An SCN2A mutation in a family with infantile seizures from Madagascar reveals an increased subthreshold Na+ current.
- Author
-
Lauxmann, Stephan, Boutry‐Kryza, Nadia, Rivier, Clotilde, Mueller, Stephan, Hedrich, Ulrike B. S., Maljevic, Snezana, Szepetowski, Pierre, Lerche, Holger, and Lesca, Gaetan
- Subjects
EPILEPSY research ,ION channels ,SODIUM channels ,ELECTROENCEPHALOGRAPHY ,SPASMS ,MISSENSE mutation - Abstract
Missense mutations in SCN2A, encoding the brain sodium channel Na
V 1.2, have been described in benign familial neonatal-infantile seizures ( BFNIS), a self-limiting disorder, whereas several SCN2A de novo nonsense mutations have been found in patients with more severe phenotypes including epileptic encephalopathy. We report a family with BFNIS originating from Madagascar. Onset extended from 3 to 9 months of age. Interictal EEGs were normal. In two patients, ictal electroencephalography ( EEG) studies showed partial seizure patterns with secondary generalization in one. Seizures remitted before 18 months of age, with or without medication. Intellectual development was normal. A novel missense mutation of SCN2A, c.4766A>G/p.Tyr1589Cys, was found in a highly conserved region of NaV 1.2 (D4/S2-S3). Functional studies using heterologous expression in tsA201 cells and whole-cell patch clamping revealed a depolarizing shift of steady-state inactivation, increased persistent Na+ current, a slowing of fast inactivation and an acceleration of its recovery, thus a gain-of-function. Using an action potential waveform in a voltage-clamp experiment we indicated an increased inward Na+ current at subthreshold voltages, which can explain a neuronal hyperexcitability. Our results suggest that this mutation induces neuronal hyperexcitability, resulting in infantile epilepsy with favorable outcome. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
30. Characterization of a descending pathway: activation and effects on motor patterns in the brachyuran crustacean stomatogastric nervous system.
- Author
-
Hedrich, Ulrike B. S. and Stein, Wolfgang
- Subjects
- *
MOTOR ability , *CENTRAL nervous system , *NEURAL stimulation , *CRABS , *INGESTION , *METABOLISM - Abstract
The regulation of motor patterns by higher-order neuronal centers ensures appropriate motor function and behavior, but only a few studies have characterized this regulation at the cellular level. Here, we address motor pattern regulation in the stomatogastric nervous system (STNS) of the crab Cancer pagurus. This easily accessible model system is an extension of the central nervous system and contains the motor circuits that generate the rhythmic motor patterns for ingestion (esophageal rhythm) and processing of food (gastric mill and pyloric rhythms). We have documented the actions of two identified neurons located in the brain on the STNS motor circuits. We show that these neurons provide exteroceptive chemosensory information to the motor circuits and we outline their axonal projection patterns, their firing activity and their effects on three motor patterns. Backfill stainings and activity measurements in vivo and in vitro show that two neurons located in cluster 17 of the brain project via the inferior ventricular (IV) nerve to the STNS. These IV neurons started to burst rhythmically when chemosensory stimuli were applied to the first antennae. When rhythmically activated in vitro, gastric mill rhythms were elicited or, if already active, entrained by the IV neuron activity. In addition, IV neuron stimulation excited the esophageal motor neuron and inhibited several pyloric neurons such that the timing of the IV neuron activity was imposed on all motor rhythms. The IV neurons were thus capable of synchronizing the activities of different motor circuits, which demonstrates the regulation of motor patterns by higher-order neuronal centers. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
31. Functional consequences of activity-dependent synaptic enhancement at a crustacean neuromuscular junction.
- Author
-
Stein, Wolfgang, Smarandache, Carmen R., Nickmann, Melanie, and Hedrich, Ulrike B. S.
- Subjects
NEUROMUSCULAR transmission ,MYONEURAL junction ,STOMACH physiology ,MUSCLES ,NEUROMUSCULAR system ,CRUSTACEA - Abstract
This study provides evidence that activity-dependent synaptic enhancement at a neuromuscular junction modifies the characteristics of force production of the receiving muscle during rhythmic motor neuron discharge patterns. Long-lasting augmentation of the excitatory junction potentials (EJPs) quickens and strengthens the muscle response to a given motor pattern. We used the muscle gm6 of the crab Cancer pagurus to study the functional consequences and temporal dynamics of facilitation and augmentation. This stomach muscle is driven by the rhythmic activity of the gastric mill central pattern generator in the stomatogastric nervous system. We tested the response of this muscle to rhythmic motor drive using a variety of gastric mill-like stimulations. EJPs recorded in muscle gm6 were initially small but are summated and facilitated strongly with continuous stimulation. Facilitation increased with shorter interspike intervals and possessed a time constant of decay <1 s. During gastric mill rhythms, motor neuron activity was by contrast represented by bursts of activity with intermittent pauses of several seconds. Recordings in intact animals and in the isolated nervous system showed a great variability in firing frequency and temporal distribution of motor neuron bursts. Train stimulations with various stimulus frequencies (5 Hz, 10 Hz, 20 Hz) and inter-train intervals (2 s, 4 s, 8 s, 16 s, 32 s) revealed that augmentation acted in addition to facilitation. Augmentation increased muscle EJPs during stimulations with inter-train intervals of 16 s or less. The effects of augmentation increased with shorter inter-train intervals, but were independent of stimulus frequency. Augmentation also contributed to the electrical response of the muscle during gastric mill rhythms, which were obtained in vitro and in vivo, and was also reflected by an increase of muscle force and the slope of force development during repetitive train stimulation. We conclude that the augmentation of EJPs at the neuromuscular junction tunes the muscle response to support force production during rhythmic motor patterns. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
32. Early-onset familial hemiplegic migraine due to a novel SCN1A mutation.
- Author
-
Fan, Chunxiang, Wolking, Stefan, Lehmann-Horn, Frank, Hedrich, Ulrike B. S., Freilinger, Tobias, Lerche, Holger, Borck, Guntram, Kubisch, Christian, Jurkat-Rott, Karin, and Hedrich, Ulrike Bs
- Subjects
- *
MIGRAINE , *GENETIC mutation , *GENETIC testing , *INTERNEURONS , *ELECTROPHYSIOLOGY , *GENETICS , *MIGRAINE diagnosis , *DISEASE susceptibility , *GENEALOGY , *GENETIC polymorphisms , *GENETIC techniques , *GENETIC markers , *MEMBRANE transport proteins - Abstract
Introduction Familial hemiplegic migraine (FHM) is a rare autosomal dominant subtype of migraine with aura. The FHM3 subtype is caused by mutations in SCN1A, which is also the most frequent epilepsy gene encoding the voltage-gated Na+ channel NaV1.1. The aim of this study was to explore the clinical, genetic and pathogenetic features of a pure FHM3 family. Methods A three-generation family was enrolled in this study for genetic testing and assessment of clinical features. Whole cell patch-clamp was performed to determine the functions of identified mutant NaV1.1 channels, which were transiently expressed in human tsA201 cells together with β1 and β2 subunits. Results and conclusions We identified a novel SCN1A (p.Leu1624Pro) mutation in a pure FHM family with notably early-onset attacks at mean age of 7. L1624P locates in S3 of domain IV, the same domain as two of four known pure FHM3 mutations. Compared to WT channels, L1624P displayed an increased threshold-near persistent current in addition to other gain-of-function features such as: a slowing of fast inactivation, a positive shift in steady-state inactivation, a faster recovery and higher channel availability during repetitive stimulation. Similar to the known FHM3 mutations, this novel mutation predicts hyperexcitability of GABAergic inhibitory neurons. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
33. Genotype-phenotype correlations in SCN8A-related disorders reveal prognostic and therapeutic implications.
- Author
-
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, Canafoglia L, Franceschetti S, Mayer T, Rebstock J, Zacher P, Ruf S, Alber M, Sterbova K, Lassuthová P, Vlckova M, Lemke JR, Platzer K, Krey I, Heine C, Wieczorek D, Kroell-Seger J, Lund C, Klein KM, Au PYB, Rho JM, Ho AW, Masnada S, Veggiotti P, Giordano L, Accorsi P, Hoei-Hansen CE, Striano P, Zara F, Verhelst H, Verhoeven JS, Braakman HMH, van der Zwaag B, Harder AVE, Brilstra E, Pendziwiat M, Lebon S, Vaccarezza M, Le NM, Christensen J, Grønborg S, Scherer SW, Howe J, Fazeli W, Howell KB, Leventer R, Stutterd C, Walsh S, Gerard M, Gerard B, Matricardi S, Bonardi CM, Sartori S, Berger A, Hoffman-Zacharska D, Mastrangelo M, Darra F, Vøllo A, Motazacker MM, Lakeman P, Nizon M, Betzler C, Altuzarra C, Caume R, Roubertie A, Gélisse P, Marini C, Guerrini R, Bilan F, Tibussek D, Koch-Hogrebe M, Perry MS, Ichikawa S, Dadali E, Sharkov A, Mishina I, Abramov M, Kanivets I, Korostelev S, Kutsev S, Wain KE, Eisenhauer N, Wagner M, Savatt JM, Müller-Schlüter K, Bassan H, Borovikov A, Nassogne MC, Destrée A, Schoonjans AS, Meuwissen M, Buzatu M, Jansen A, Scalais E, Srivastava S, Tan WH, Olson HE, Loddenkemper T, Poduri A, Helbig KL, Helbig I, Fitzgerald MP, Goldberg EM, Roser T, Borggraefe I, Brünger T, May P, Lal D, Lederer D, Rubboli G, Heyne HO, Lesca G, Hedrich UBS, Benda J, Gardella E, Lerche H, and Møller RS
- Subjects
- Genetic Association Studies, Humans, Infant, Mutation, Prognosis, Seizures drug therapy, Seizures genetics, Sodium Channel Blockers therapeutic use, Epilepsy, Generalized drug therapy, Epilepsy, Generalized genetics, Epileptic Syndromes drug therapy, Epileptic Syndromes genetics, Intellectual Disability genetics, NAV1.6 Voltage-Gated Sodium Channel genetics
- Abstract
We report detailed functional analyses and genotype-phenotype correlations in 392 individuals carrying disease-causing variants in SCN8A, encoding the voltage-gated Na+ channel Nav1.6, with the aim of describing clinical phenotypes related to functional effects. Six different clinical subgroups were identified: Group 1, benign familial infantile epilepsy (n = 15, normal cognition, treatable seizures); Group 2, intermediate epilepsy (n = 33, mild intellectual disability, partially pharmaco-responsive); Group 3, developmental and epileptic encephalopathy (n = 177, severe intellectual disability, majority pharmaco-resistant); Group 4, generalized epilepsy (n = 20, mild to moderate intellectual disability, frequently with absence seizures); Group 5, unclassifiable epilepsy (n = 127); and Group 6, neurodevelopmental disorder without epilepsy (n = 20, mild to moderate intellectual disability). Those in Groups 1-3 presented with focal or multifocal seizures (median age of onset: 4 months) and focal epileptiform discharges, whereas the onset of seizures in patients with generalized epilepsy was later (median: 42 months) with generalized epileptiform discharges. We performed functional studies expressing missense variants in ND7/23 neuroblastoma cells and primary neuronal cultures using recombinant tetrodotoxin-insensitive human Nav1.6 channels and whole-cell patch-clamping. Two variants causing developmental and epileptic encephalopathy showed a strong gain-of-function (hyperpolarizing shift of steady-state activation, strongly increased neuronal firing rate) and one variant causing benign familial infantile epilepsy or intermediate epilepsy showed a mild gain-of-function (defective fast inactivation, less increased firing). In contrast, all three variants causing generalized epilepsy induced a loss-of-function (reduced current amplitudes, depolarizing shift of steady-state activation, reduced neuronal firing). Functional effects were known for 170 individuals. All 136 individuals carrying a functionally tested gain-of-function variant had either focal (n = 97, Groups 1-3) or unclassifiable (n = 39) epilepsy, whereas 34 individuals with a loss-of-function variant had either generalized (n = 14), no (n = 11) or unclassifiable (n = 6) epilepsy; only three had developmental and epileptic encephalopathy. Computational modelling in the gain-of-function group revealed a significant correlation between the severity of the electrophysiological and clinical phenotypes. Gain-of-function variant carriers responded significantly better to sodium channel blockers than to other anti-seizure medications, and the same applied for all individuals in Groups 1-3. In conclusion, our data reveal clear genotype-phenotype correlations between age at seizure onset, type of epilepsy and gain- or loss-of-function effects of SCN8A variants. Generalized epilepsy with absence seizures is the main epilepsy phenotype of loss-of-function variant carriers and the extent of the electrophysiological dysfunction of the gain-of-function variants is a main determinant of the severity of the clinical phenotype in focal epilepsies. Our pharmacological data indicate that sodium channel blockers present a treatment option in SCN8A-related focal epilepsy with onset in the first year of life., (© The Author(s) (2021). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please email: journals.permissions@oup.com.)
- Published
- 2022
- Full Text
- View/download PDF
34. Predicting the functional effects of voltage-gated potassium channel missense variants with multi-task learning.
- Author
-
Boßelmann CM, Hedrich UBS, Müller P, Sonnenberg L, Parthasarathy S, Helbig I, Lerche H, and Pfeifer N
- Subjects
- Humans, Mutation, Missense, Shaw Potassium Channels genetics, Epilepsy genetics, Intellectual Disability genetics, Potassium Channels, Voltage-Gated chemistry, Potassium Channels, Voltage-Gated genetics
- Abstract
Background: Variants in genes encoding voltage-gated potassium channels are associated with a broad spectrum of neurological diseases including epilepsy, ataxia, and intellectual disability. Knowledge of the resulting functional changes, characterized as overall ion channel gain- or loss-of-function, is essential to guide clinical management including precision medicine therapies. However, for an increasing number of variants, little to no experimental data is available. New tools are needed to evaluate variant functional effects., Methods: We catalogued a comprehensive dataset of 959 functional experiments across 19 voltage-gated potassium channels, leveraging data from 782 unique disease-associated and synthetic variants. We used these data to train a taxonomy-based multi-task learning support vector machine (MTL-SVM), and compared performance to several baseline methods., Findings: MTL-SVM maintains channel family structure during model training, improving overall predictive performance (mean balanced accuracy 0·718 ± 0·041, AU-ROC 0·761 ± 0·063) over baseline (mean balanced accuracy 0·620 ± 0·045, AU-ROC 0·711 ± 0·022). We can obtain meaningful predictions even for channels with few known variants (KCNC1, KCNQ5)., Interpretation: Our model enables functional variant prediction for voltage-gated potassium channels. It may assist in tailoring current and future precision therapies for the increasing number of patients with ion channel disorders., Funding: This work was supported by intramural funding of the Medical Faculty, University of Tuebingen (PATE F.1315137.1), the Federal Ministry for Education and Research (Treat-ION, 01GM1907A/B/G/H) and the German Research Foundation (FOR-2715, Le1030/16-2, He8155/1-2)., Competing Interests: Declaration of interests The authors declare no conflict of interest related to this work., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2022
- Full Text
- View/download PDF
35. Spectrum of Phenotypic, Genetic, and Functional Characteristics in Patients With Epilepsy With KCNC2 Pathogenic Variants.
- Author
-
Schwarz N, Seiffert S, Pendziwiat M, Rademacher AV, Brünger T, Hedrich UBS, Augustijn PB, Baier H, Bayat A, Bisulli F, Buono RJ, Bruria BZ, Doyle MG, Guerrini R, Heimer G, Iacomino M, Kearney H, Klein KM, Kousiappa I, Kunz WS, Lerche H, Licchetta L, Lohmann E, Minardi R, McDonald M, Montgomery S, Mulahasanovic L, Oegema R, Ortal B, Papacostas SS, Ragona F, Granata T, Reif PS, Rosenow F, Rothschild A, Scudieri P, Striano P, Tinuper P, Tanteles GA, Vetro A, Zahnert F, Goldberg EM, Zara F, Lal D, May P, Muhle H, Helbig I, and Weber Y
- Subjects
- Humans, Phenotype, Seizures genetics, Shaw Potassium Channels genetics, Exome Sequencing, Epilepsy genetics, Epilepsy, Generalized genetics
- Abstract
Background and Objectives: KCNC2 encodes Kv3.2, a member of the Shaw-related (Kv3) voltage-gated potassium channel subfamily, which is important for sustained high-frequency firing and optimized energy efficiency of action potentials in the brain. The objective of this study was to analyze the clinical phenotype, genetic background, and biophysical function of disease-associated Kv3.2 variants., Methods: Individuals with KCNC2 variants detected by exome sequencing were selected for clinical, further genetic, and functional analysis. Cases were referred through clinical and research collaborations. Selected de novo variants were examined electrophysiologically in Xenopus laevis oocytes., Results: We identified novel KCNC2 variants in 18 patients with various forms of epilepsy, including genetic generalized epilepsy (GGE), developmental and epileptic encephalopathy (DEE) including early-onset absence epilepsy, focal epilepsy, and myoclonic-atonic epilepsy. Of the 18 variants, 10 were de novo and 8 were classified as modifying variants. Eight drug-responsive patients became seizure-free using valproic acid as monotherapy or in combination, including severe DEE cases. Functional analysis of 4 variants demonstrated gain of function in 3 severely affected DEE cases and loss of function in 1 case with a milder phenotype (GGE) as the underlying pathomechanisms., Discussion: These findings implicate KCNC2 as a novel causative gene for epilepsy and emphasize the critical role of K
V 3.2 in the regulation of brain excitability., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)- Published
- 2022
- Full Text
- View/download PDF
36. Dravet Variant SCN1A A 1783 V Impairs Interneuron Firing Predominantly by Altered Channel Activation.
- Author
-
Layer N, Sonnenberg L, Pardo González E, Benda J, Hedrich UBS, Lerche H, Koch H, and Wuttke TV
- Abstract
Dravet syndrome (DS) is a developmental epileptic encephalopathy mainly caused by functional Na
V 1.1 haploinsufficiency in inhibitory interneurons. Recently, a new conditional mouse model expressing the recurrent human p.(Ala1783Val) missense variant has become available. In this study, we provided an electrophysiological characterization of this variant in tsA201 cells, revealing both altered voltage-dependence of activation and slow inactivation without reduced sodium peak current density. Based on these data, simulated interneuron (IN) firing properties in a conductance-based single-compartment model suggested surprisingly similar firing deficits for NaV 1.1A1783V and full haploinsufficiency as caused by heterozygous truncation variants. Impaired NaV 1.1A1783V channel activation was predicted to have a significantly larger impact on channel function than altered slow inactivation and is therefore proposed as the main mechanism underlying IN dysfunction. The computational model was validated in cortical organotypic slice cultures derived from conditional Scn1aA 1783 V mice. Pan-neuronal activation of the p.Ala1783V in vitro confirmed a predicted IN firing deficit and revealed an accompanying reduction of interneuronal input resistance while demonstrating normal excitability of pyramidal neurons. Altered input resistance was fed back into the model for further refinement. Taken together these data demonstrate that primary loss of function (LOF) gating properties accompanied by altered membrane characteristics may match effects of full haploinsufficiency on the neuronal level despite maintaining physiological peak current density, thereby causing DS., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Layer, Sonnenberg, Pardo González, Benda, Hedrich, Lerche, Koch and Wuttke.)- Published
- 2021
- Full Text
- View/download PDF
37. Novel treatment approaches and pediatric research networks in status epilepticus.
- Author
-
Bialer M, Cross H, Hedrich UBS, Lagae L, Lerche H, and Loddenkemper T
- Subjects
- Animals, Child, Humans, Sodium Channels genetics, Sodium Channels metabolism, Status Epilepticus drug therapy, Status Epilepticus genetics, Anticonvulsants therapeutic use, Pediatrics methods, Research, Status Epilepticus therapy
- Abstract
This paper contains five contributions which were presented as part of the novel therapies section of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures. These illustrate recent advances being made in the management and therapy of status epilepticus. The five contributions concern: genetic variations in Na + channel genes and their importance in status epilepticus; the European Reference Network for rare and complex epilepsies EpiCARE; the North American Pediatric Status Epilepticus Research Group (pSERG); Fenfluramine as a potential therapy for status epilepticus' and the valproate derivatives, valnoctamide and sec-butylpropylacetamide (SPD), as potential therapies for status epilepticus. This article is part of the Special Issue "Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures"., (Copyright © 2019 Elsevier Inc. All rights reserved.)
- Published
- 2019
- Full Text
- View/download PDF
38. KCNC1-related disorders: new de novo variants expand the phenotypic spectrum.
- Author
-
Park J, Koko M, Hedrich UBS, Hermann A, Cremer K, Haberlandt E, Grimmel M, Alhaddad B, Beck-Woedl S, Harrer M, Karall D, Kingelhoefer L, Tzschach A, Matthies LC, Strom TM, Ringelstein EB, Sturm M, Engels H, Wolff M, Lerche H, and Haack TB
- Subjects
- Animals, Ataxia genetics, Child, Codon, Nonsense, Humans, Intellectual Disability genetics, Male, Myoclonic Epilepsies, Progressive, Seizures genetics, Shaw Potassium Channels physiology, Xenopus laevis, Genetic Association Studies, Mutation, Missense, Shaw Potassium Channels genetics
- Abstract
A recurrent de novo missense variant in KCNC1, encoding a voltage-gated potassium channel expressed in inhibitory neurons, causes progressive myoclonus epilepsy and ataxia, and a nonsense variant is associated with intellectual disability. We identified three new de novo missense variants in KCNC1 in five unrelated individuals causing different phenotypes featuring either isolated nonprogressive myoclonus (p.Cys208Tyr), intellectual disability (p.Thr399Met), or epilepsy with myoclonic, absence and generalized tonic-clonic seizures, ataxia, and developmental delay (p.Ala421Val, three patients). Functional analyses demonstrated no measurable currents for all identified variants and dominant-negative effects for p.Thr399Met and p.Ala421Val predicting neuronal disinhibition as the underlying disease mechanism., (© 2019 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals, Inc on behalf of American Neurological Association.)
- Published
- 2019
- Full Text
- View/download PDF
39. De Novo Pathogenic Variants in CACNA1E Cause Developmental and Epileptic Encephalopathy with Contractures, Macrocephaly, and Dyskinesias.
- Author
-
Helbig KL, Lauerer RJ, Bahr JC, Souza IA, Myers CT, Uysal B, Schwarz N, Gandini MA, Huang S, Keren B, Mignot C, Afenjar A, Billette de Villemeur T, Héron D, Nava C, Valence S, Buratti J, Fagerberg CR, Soerensen KP, Kibaek M, Kamsteeg EJ, Koolen DA, Gunning B, Schelhaas HJ, Kruer MC, Fox J, Bakhtiari S, Jarrar R, Padilla-Lopez S, Lindstrom K, Jin SC, Zeng X, Bilguvar K, Papavasileiou A, Xing Q, Zhu C, Boysen K, Vairo F, Lanpher BC, Klee EW, Tillema JM, Payne ET, Cousin MA, Kruisselbrink TM, Wick MJ, Baker J, Haan E, Smith N, Sadeghpour A, Davis EE, Katsanis N, Corbett MA, MacLennan AH, Gecz J, Biskup S, Goldmann E, Rodan LH, Kichula E, Segal E, Jackson KE, Asamoah A, Dimmock D, McCarrier J, Botto LD, Filloux F, Tvrdik T, Cascino GD, Klingerman S, Neumann C, Wang R, Jacobsen JC, Nolan MA, Snell RG, Lehnert K, Sadleir LG, Anderlid BM, Kvarnung M, Guerrini R, Friez MJ, Lyons MJ, Leonhard J, Kringlen G, Casas K, El Achkar CM, Smith LA, Rotenberg A, Poduri A, Sanchis-Juan A, Carss KJ, Rankin J, Zeman A, Raymond FL, Blyth M, Kerr B, Ruiz K, Urquhart J, Hughes I, Banka S, Hedrich UBS, Scheffer IE, Helbig I, Zamponi GW, Lerche H, and Mefford HC
- Published
- 2019
- Full Text
- View/download PDF
40. Relationship of electrophysiological dysfunction and clinical severity in SCN2A-related epilepsies.
- Author
-
Lauxmann S, Verbeek NE, Liu Y, Zaichuk M, Müller S, Lemke JR, van Kempen MJA, Lerche H, and Hedrich UBS
- Subjects
- Cell Line, Electrophysiological Phenomena, Epileptic Syndromes genetics, Epileptic Syndromes metabolism, Female, Genetic Variation, Humans, Infant, Infant, Newborn, Male, Pedigree, Phenotype, Severity of Illness Index, Amino Acid Substitution, Epileptic Syndromes physiopathology, NAV1.2 Voltage-Gated Sodium Channel genetics, NAV1.2 Voltage-Gated Sodium Channel metabolism
- Abstract
Variants in the SCN2A gene cause a broad spectrum of epilepsy syndromes of variable severity including benign neonatal-infantile epilepsy (BFNIE), developmental and epileptic encephalopathies (DEE), and other neuropsychiatric disorders. Here, we studied three newly identified variants, which caused distinct phenotypes observed in nine affected individuals of three families, including BFNIE, and DEE with intractable neonatal seizures. Whole cell patch-clamp recordings of transfected tsA201 cells disclosed an increased current density and an increased subthreshold sodium inward current upon an action potential stimulus (p.(Lys908Glu)), a hyperpolarizing shift of the activation curve (p.(Val208Glu) and p.(Thr773Ile)), and an increased persistent current (p.(Thr773Ile)). To evaluate genotype-phenotype correlations, we next developed scoring systems for both the extent of the electrophysiological dysfunction and the severity of the clinical phenotype and applied those to 21 previously and newly functionally characterized SCN2A variants. All inherited variants were associated with a mild clinical phenotype and a lower electrophysiological score compared to those occurring de novo and causing severe phenotypes. Our results thus reveal a nice correlation between the extent of channel dysfunction and the clinical severity., (© 2018 Wiley Periodicals, Inc.)
- Published
- 2018
- Full Text
- View/download PDF
41. De Novo Pathogenic Variants in CACNA1E Cause Developmental and Epileptic Encephalopathy with Contractures, Macrocephaly, and Dyskinesias.
- Author
-
Helbig KL, Lauerer RJ, Bahr JC, Souza IA, Myers CT, Uysal B, Schwarz N, Gandini MA, Huang S, Keren B, Mignot C, Afenjar A, Billette de Villemeur T, Héron D, Nava C, Valence S, Buratti J, Fagerberg CR, Soerensen KP, Kibaek M, Kamsteeg EJ, Koolen DA, Gunning B, Schelhaas HJ, Kruer MC, Fox J, Bakhtiari S, Jarrar R, Padilla-Lopez S, Lindstrom K, Jin SC, Zeng X, Bilguvar K, Papavasileiou A, Xing Q, Zhu C, Boysen K, Vairo F, Lanpher BC, Klee EW, Tillema JM, Payne ET, Cousin MA, Kruisselbrink TM, Wick MJ, Baker J, Haan E, Smith N, Sadeghpour A, Davis EE, Katsanis N, Corbett MA, MacLennan AH, Gecz J, Biskup S, Goldmann E, Rodan LH, Kichula E, Segal E, Jackson KE, Asamoah A, Dimmock D, McCarrier J, Botto LD, Filloux F, Tvrdik T, Cascino GD, Klingerman S, Neumann C, Wang R, Jacobsen JC, Nolan MA, Snell RG, Lehnert K, Sadleir LG, Anderlid BM, Kvarnung M, Guerrini R, Friez MJ, Lyons MJ, Leonhard J, Kringlen G, Casas K, El Achkar CM, Smith LA, Rotenberg A, Poduri A, Sanchis-Juan A, Carss KJ, Rankin J, Zeman A, Raymond FL, Blyth M, Kerr B, Ruiz K, Urquhart J, Hughes I, Banka S, Hedrich UBS, Scheffer IE, Helbig I, Zamponi GW, Lerche H, and Mefford HC
- Subjects
- Adolescent, Adult, Child, Child, Preschool, Female, Humans, Infant, Male, Neurodevelopmental Disorders genetics, Calcium Channels, R-Type genetics, Cation Transport Proteins genetics, Contracture genetics, Dyskinesias genetics, Epilepsy genetics, Genetic Variation genetics, Megalencephaly genetics, Spasms, Infantile genetics
- Abstract
Developmental and epileptic encephalopathies (DEEs) are severe neurodevelopmental disorders often beginning in infancy or early childhood that are characterized by intractable seizures, abundant epileptiform activity on EEG, and developmental impairment or regression. CACNA1E is highly expressed in the central nervous system and encodes the α
1 -subunit of the voltage-gated CaV 2.3 channel, which conducts high voltage-activated R-type calcium currents that initiate synaptic transmission. Using next-generation sequencing techniques, we identified de novo CACNA1E variants in 30 individuals with DEE, characterized by refractory infantile-onset seizures, severe hypotonia, and profound developmental impairment, often with congenital contractures, macrocephaly, hyperkinetic movement disorders, and early death. Most of the 14, partially recurring, variants cluster within the cytoplasmic ends of all four S6 segments, which form the presumed CaV 2.3 channel activation gate. Functional analysis of several S6 variants revealed consistent gain-of-function effects comprising facilitated voltage-dependent activation and slowed inactivation. Another variant located in the domain II S4-S5 linker results in facilitated activation and increased current density. Five participants achieved seizure freedom on the anti-epileptic drug topiramate, which blocks R-type calcium channels. We establish pathogenic variants in CACNA1E as a cause of DEEs and suggest facilitated R-type calcium currents as a disease mechanism for human epilepsy and developmental disorders., (Copyright © 2018 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)- Published
- 2018
- Full Text
- View/download PDF
42. Human Cerebrospinal fluid promotes long-term neuronal viability and network function in human neocortical organotypic brain slice cultures.
- Author
-
Schwarz N, Hedrich UBS, Schwarz H, P A H, Dammeier N, Auffenberg E, Bedogni F, Honegger JB, Lerche H, Wuttke TV, and Koch H
- Subjects
- Autopsy, Cell Survival, Humans, Cerebral Cortex physiology, Cerebrospinal Fluid metabolism, Culture Media metabolism, Neurons physiology, Organ Culture Techniques methods, Pathology methods
- Abstract
Pathophysiological investigation of CNS-related diseases, such as epilepsy or neurodegenerative disorders, largely relies on histological studies on human post mortem tissue, tissue obtained by biopsy or resective surgery and on studies using disease models including animal models, heterologous expression systems or cell culture based approaches. However, in general it remains elusive to what extent results obtained in model systems can be directly translated to the human brain, calling for strategies allowing validation or even primary investigation in live human CNS tissue. In the work reported here, we prepared human organotypic slice cultures from access tissue of resective epilepsy surgery. Employing different culture conditions, we systematically compared artificial culturing media versus human cerbrospinal fluid (hCSF) obtained from patients with normal pressure hydrocephalus (NPH). Presented data demonstrates sustained cortical neuronal survival including not only maintenance of typical cellular electrophysiological properties and activity, such as robust action potential generation and synaptic connectivity, but also preservation of tonic and phasic network activity up to several weeks in vitro. As clearly delineated by immunocytochemistry, single cell patch clamp and extracellular recordings, we find that in contrast to artificial culturing media, hCSF significantly enhances neuron viability and maintenance of network activity.
- Published
- 2017
- Full Text
- View/download PDF
43. Genetic and phenotypic heterogeneity suggest therapeutic implications in SCN2A-related disorders.
- Author
-
Wolff M, Johannesen KM, Hedrich UBS, Masnada S, Rubboli G, Gardella E, Lesca G, Ville D, Milh M, Villard L, Afenjar A, Chantot-Bastaraud S, Mignot C, Lardennois C, Nava C, Schwarz N, Gérard M, Perrin L, Doummar D, Auvin S, Miranda MJ, Hempel M, Brilstra E, Knoers N, Verbeek N, van Kempen M, Braun KP, Mancini G, Biskup S, Hörtnagel K, Döcker M, Bast T, Loddenkemper T, Wong-Kisiel L, Baumeister FM, Fazeli W, Striano P, Dilena R, Fontana E, Zara F, Kurlemann G, Klepper J, Thoene JG, Arndt DH, Deconinck N, Schmitt-Mechelke T, Maier O, Muhle H, Wical B, Finetti C, Brückner R, Pietz J, Golla G, Jillella D, Linnet KM, Charles P, Moog U, Õiglane-Shlik E, Mantovani JF, Park K, Deprez M, Lederer D, Mary S, Scalais E, Selim L, Van Coster R, Lagae L, Nikanorova M, Hjalgrim H, Korenke GC, Trivisano M, Specchio N, Ceulemans B, Dorn T, Helbig KL, Hardies K, Stamberger H, de Jonghe P, Weckhuysen S, Lemke JR, Krägeloh-Mann I, Helbig I, Kluger G, Lerche H, and Møller RS
- Subjects
- Adolescent, Adult, Age of Onset, Child, Child, Preschool, Denmark epidemiology, Epilepsy epidemiology, Female, Humans, Infant, Male, Mutation, Phenotype, Young Adult, Epilepsy drug therapy, Epilepsy genetics, Epilepsy physiopathology, NAV1.2 Voltage-Gated Sodium Channel genetics, NAV1.2 Voltage-Gated Sodium Channel physiology, Neurodevelopmental Disorders genetics, Sodium Channel Blockers therapeutic use
- Abstract
Mutations in SCN2A, a gene encoding the voltage-gated sodium channel Nav1.2, have been associated with a spectrum of epilepsies and neurodevelopmental disorders. Here, we report the phenotypes of 71 patients and review 130 previously reported patients. We found that (i) encephalopathies with infantile/childhood onset epilepsies (≥3 months of age) occur almost as often as those with an early infantile onset (<3 months), and are thus more frequent than previously reported; (ii) distinct phenotypes can be seen within the late onset group, including myoclonic-atonic epilepsy (two patients), Lennox-Gastaut not emerging from West syndrome (two patients), and focal epilepsies with an electrical status epilepticus during slow sleep-like EEG pattern (six patients); and (iii) West syndrome constitutes a common phenotype with a major recurring mutation (p.Arg853Gln: two new and four previously reported children). Other known phenotypes include Ohtahara syndrome, epilepsy of infancy with migrating focal seizures, and intellectual disability or autism without epilepsy. To assess the response to antiepileptic therapy, we retrospectively reviewed the treatment regimen and the course of the epilepsy in 66 patients for which well-documented medical information was available. We find that the use of sodium channel blockers was often associated with clinically relevant seizure reduction or seizure freedom in children with early infantile epilepsies (<3 months), whereas other antiepileptic drugs were less effective. In contrast, sodium channel blockers were rarely effective in epilepsies with later onset (≥3 months) and sometimes induced seizure worsening. Regarding the genetic findings, truncating mutations were exclusively seen in patients with late onset epilepsies and lack of response to sodium channel blockers. Functional characterization of four selected missense mutations using whole cell patch-clamping in tsA201 cells-together with data from the literature-suggest that mutations associated with early infantile epilepsy result in increased sodium channel activity with gain-of-function, characterized by slowing of fast inactivation, acceleration of its recovery or increased persistent sodium current. Further, a good response to sodium channel blockers clinically was found to be associated with a relatively small gain-of-function. In contrast, mutations in patients with late-onset forms and an insufficient response to sodium channel blockers were associated with loss-of-function effects, including a depolarizing shift of voltage-dependent activation or a hyperpolarizing shift of channel availability (steady-state inactivation). Our clinical and experimental data suggest a correlation between age at disease onset, response to sodium channel blockers and the functional properties of mutations in children with SCN2A-related epilepsy., (© The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)
- Published
- 2017
- Full Text
- View/download PDF
44. GRIN2D Recurrent De Novo Dominant Mutation Causes a Severe Epileptic Encephalopathy Treatable with NMDA Receptor Channel Blockers.
- Author
-
Li D, Yuan H, Ortiz-Gonzalez XR, Marsh ED, Tian L, McCormick EM, Kosobucki GJ, Chen W, Schulien AJ, Chiavacci R, Tankovic A, Naase C, Brueckner F, von Stülpnagel-Steinbeis C, Hu C, Kusumoto H, Hedrich UB, Elsen G, Hörtnagel K, Aizenman E, Lemke JR, Hakonarson H, Traynelis SF, and Falk MJ
- Subjects
- Amino Acid Sequence, Base Sequence, Cell Death, Child, DNA Mutational Analysis, Dendrites pathology, Electroencephalography, Exome genetics, Female, Glutamic Acid metabolism, Humans, Infant, Infant, Newborn, Ketamine therapeutic use, Magnesium therapeutic use, Memantine administration & dosage, Memantine therapeutic use, Models, Molecular, Precision Medicine, Receptors, N-Methyl-D-Aspartate chemistry, Receptors, N-Methyl-D-Aspartate genetics, Receptors, N-Methyl-D-Aspartate metabolism, Seizures drug therapy, Seizures genetics, Seizures metabolism, Spasms, Infantile metabolism, Genes, Dominant genetics, Mutation, Receptors, N-Methyl-D-Aspartate antagonists & inhibitors, Spasms, Infantile drug therapy, Spasms, Infantile genetics
- Abstract
N-methyl-D-aspartate receptors (NMDARs) are ligand-gated cation channels that mediate excitatory synaptic transmission. Genetic mutations in multiple NMDAR subunits cause various childhood epilepsy syndromes. Here, we report a de novo recurrent heterozygous missense mutation-c.1999G>A (p.Val667Ile)-in a NMDAR gene previously unrecognized to harbor disease-causing mutations, GRIN2D, identified by exome and candidate panel sequencing in two unrelated children with epileptic encephalopathy. The resulting GluN2D p.Val667Ile exchange occurs in the M3 transmembrane domain involved in channel gating. This gain-of-function mutation increases glutamate and glycine potency by 2-fold, increases channel open probability by 6-fold, and reduces receptor sensitivity to endogenous negative modulators such as extracellular protons. Moreover, this mutation prolongs the deactivation time course after glutamate removal, which controls the synaptic time course. Transfection of cultured neurons with human GRIN2D cDNA harboring c.1999G>A leads to dendritic swelling and neuronal cell death, suggestive of excitotoxicity mediated by NMDAR over-activation. Because both individuals' seizures had proven refractory to conventional antiepileptic medications, the sensitivity of mutant NMDARs to FDA-approved NMDAR antagonists was evaluated. Based on these results, oral memantine was administered to both children, with resulting mild to moderate improvement in seizure burden and development. The older proband subsequently developed refractory status epilepticus, with dramatic electroclinical improvement upon treatment with ketamine and magnesium. Overall, these results suggest that NMDAR antagonists can be useful as adjuvant epilepsy therapy in individuals with GRIN2D gain-of-function mutations. This work further demonstrates the value of functionally evaluating a mutation, enabling mechanistic understanding and therapeutic modeling to realize precision medicine for epilepsy., (Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)
- Published
- 2016
- Full Text
- View/download PDF
45. A recurrent mutation in KCNA2 as a novel cause of hereditary spastic paraplegia and ataxia.
- Author
-
Helbig KL, Hedrich UB, Shinde DN, Krey I, Teichmann AC, Hentschel J, Schubert J, Chamberlin AC, Huether R, Lu HM, Alcaraz WA, Tang S, Jungbluth C, Dugan SL, Vainionpää L, Karle KN, Synofzik M, Schöls L, Schüle R, Lehesjoki AE, Helbig I, Lerche H, and Lemke JR
- Subjects
- Adult, Animals, Ataxia physiopathology, Child, Exome, Female, Humans, Intellectual Disability physiopathology, Male, Middle Aged, Mutation, Oocytes metabolism, Pedigree, Spastic Paraplegia, Hereditary physiopathology, Xenopus laevis, Young Adult, Ataxia genetics, Intellectual Disability genetics, Kv1.2 Potassium Channel genetics, Spastic Paraplegia, Hereditary genetics
- Abstract
The hereditary spastic paraplegias (HSPs) are heterogeneous neurodegenerative disorders with over 50 known causative genes. We identified a recurrent mutation in KCNA2 (c.881G>A, p.R294H), encoding the voltage-gated K(+) -channel, KV 1.2, in two unrelated families with HSP, intellectual disability (ID), and ataxia. Follow-up analysis of > 2,000 patients with various neurological phenotypes identified a de novo p.R294H mutation in a proband with ataxia and ID. Two-electrode voltage-clamp recordings of Xenopus laevis oocytes expressing mutant KV 1.2 channels showed loss of function with a dominant-negative effect. Our findings highlight the phenotypic spectrum of a recurrent KCNA2 mutation, implicating ion channel dysfunction as a novel HSP disease mechanism. Ann Neurol 2016., (© 2016 The Authors Annals of Neurology published by Wiley Periodicals, Inc. on behalf of American Neurological Association.)
- Published
- 2016
- Full Text
- View/download PDF
46. Impaired action potential initiation in GABAergic interneurons causes hyperexcitable networks in an epileptic mouse model carrying a human Na(V)1.1 mutation.
- Author
-
Hedrich UB, Liautard C, Kirschenbaum D, Pofahl M, Lavigne J, Liu Y, Theiss S, Slotta J, Escayg A, Dihné M, Beck H, Mantegazza M, and Lerche H
- Subjects
- Animals, Axons metabolism, Axons physiology, Brain cytology, Brain metabolism, Brain physiopathology, Calcium metabolism, Cells, Cultured, Epilepsy genetics, Epilepsy metabolism, GABAergic Neurons metabolism, Humans, Inhibitory Postsynaptic Potentials, Interneurons metabolism, Interneurons physiology, Mice, Mice, Inbred C57BL, NAV1.1 Voltage-Gated Sodium Channel metabolism, Nerve Net cytology, Nerve Net metabolism, Action Potentials, Epilepsy physiopathology, GABAergic Neurons physiology, Mutation, NAV1.1 Voltage-Gated Sodium Channel genetics, Nerve Net physiopathology
- Abstract
Mutations in SCN1A and other ion channel genes can cause different epileptic phenotypes, but the precise mechanisms underlying the development of hyperexcitable networks are largely unknown. Here, we present a multisystem analysis of an SCN1A mouse model carrying the NaV1.1-R1648H mutation, which causes febrile seizures and epilepsy in humans. We found a ubiquitous hypoexcitability of interneurons in thalamus, cortex, and hippocampus, without detectable changes in excitatory neurons. Interestingly, somatic Na(+) channels in interneurons and persistent Na(+) currents were not significantly changed. Instead, the key mechanism of interneuron dysfunction was a deficit of action potential initiation at the axon initial segment that was identified by analyzing action potential firing. This deficit increased with the duration of firing periods, suggesting that increased slow inactivation, as recorded for recombinant mutated channels, could play an important role. The deficit in interneuron firing caused reduced action potential-driven inhibition of excitatory neurons as revealed by less frequent spontaneous but not miniature IPSCs. Multiple approaches indicated increased spontaneous thalamocortical and hippocampal network activity in mutant mice, as follows: (1) more synchronous and higher-frequency firing was recorded in primary neuronal cultures plated on multielectrode arrays; (2) thalamocortical slices examined by field potential recordings revealed spontaneous activities and pathological high-frequency oscillations; and (3) multineuron Ca(2+) imaging in hippocampal slices showed increased spontaneous neuronal activity. Thus, an interneuron-specific generalized defect in action potential initiation causes multisystem disinhibition and network hyperexcitability, which can well explain the occurrence of seizures in the studied mouse model and in patients carrying this mutation., (Copyright © 2014 the authors 0270-6474/14/3414874-16$15.00/0.)
- Published
- 2014
- Full Text
- View/download PDF
47. Gastric and pyloric motor pattern control by a modulatory projection neuron in the intact crab Cancer pagurus.
- Author
-
Hedrich UB, Diehl F, and Stein W
- Subjects
- Animals, Neural Pathways physiology, Pylorus innervation, Pylorus physiology, Stomach innervation, Stomach physiology, Brachyura physiology, Ganglia, Invertebrate physiology, Motor Neurons physiology
- Abstract
Neuronal release of modulatory substances provides motor pattern generating circuits with a high degree of flexibility. In vitro studies have characterized the actions of modulatory projection neurons in great detail in the stomatogastric nervous system, a model system for neuromodulatory influences on central pattern generators. Less is known about the activities and actions of modulatory neurons in fully functional and richly modulated network settings, i.e., in intact animals. It is also unknown whether their activities contribute to the motor patterns in different behavioral conditions. Here, we show for the first time the activity and effects of the well-characterized modulatory projection neuron 1 (MCN1) in vivo and compare them to in vitro conditions. MCN1 was always spontaneously active, typically in a rhythmic fashion with its firing being interrupted by ascending inhibitions from the pyloric motor circuit. Its activity contributed to pyloric motor activity, because 1) the cycle period of the motor pattern correlated with MCN1 firing frequency and 2) stimulating MCN1 shortened the cycle period while 3) lesioning of the MCN1 axon reduced motor activity. In addition, gastric mill motor activity was elicited for the duration of the stimulation. Chemosensory stimulation of the antennae moved MCN1 away from baseline activity by increasing its firing frequency. Following this increase, a gastric mill rhythm was elicited and the pyloric cycle period decreased. Lesioning the MCN1 axon prevented these effects. Thus modulatory projection neurons such as MCN1 can control the motor output in vivo, and they participate in the processing of exteroceptive sensory information in behaviorally relevant conditions.
- Published
- 2011
- Full Text
- View/download PDF
48. Differential activation of projection neurons by two sensory pathways contributes to motor pattern selection.
- Author
-
Hedrich UB, Smarandache CR, and Stein W
- Subjects
- Afferent Pathways cytology, Analysis of Variance, Animals, Brachyura physiology, In Vitro Techniques, Models, Biological, Neural Inhibition physiology, Periodicity, Physical Stimulation methods, Stomatognathic System innervation, Stomatognathic System physiology, Action Potentials physiology, Afferent Pathways physiology, Motor Activity physiology, Sensory Receptor Cells classification, Sensory Receptor Cells physiology
- Abstract
Sensorimotor integration is known to occur at the level of motor circuits as well as in upstream interneurons that regulate motor activity. Here we show, using the crab stomatogastric nervous system (STNS) as a model, that different sensory systems affect the same set of projection neurons. However, they have qualitatively different effects on their activities (excitation vs. inhibition), and these differences contribute to the selection of motor patterns from multifunctional circuits. We compare the actions of the proprioceptive anterior gastric receptor (AGR) and the inferior ventricular (IV) neurons, which relay chemosensory information from the brain to the STNS, on modulatory commissural neurons 1 and 5 (MCN1 and MCN5) and commissural projection neuron 2 (CPN2) and their resulting actions on the gastric mill central pattern generating circuit in the stomatogastric ganglion. When stimulated, AGR and the IV neurons affect all three projection neurons but elicit distinct gastric mill rhythms. The effects of both sensory pathways on the projection neurons differ in the type of excitation provided to CPN2 and MCN5 (electrical vs. chemical) and the effect on MCN1 (direct inhibition by AGR vs. polysynaptic excitation by the IV neurons). The latter is functionally important because a restoration of MCN1 activity during the AGR rhythm made it more similar to that elicited by IV neuron stimulation. Our results thus support the hypothesis that sensory pathways activate different combinations of projection neurons to select distinct outputs from the same neuronal circuit.
- Published
- 2009
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.