Seizures, behavioral deficits and adverse drug responses in two new genetic mouse models of HCN1 epileptic encephalopathy
- German Center for Neurodegenerative Diseases, Germany
- Columbia University, United States
- University of Milan, Italy
- University of Cologne, Germany
Abstract
De novo mutations in voltage- and ligand-gated channels have been associated with an increasing number of cases of developmental and epileptic encephalopathies, which often fail to respond to classic antiseizure medications. Here, we examine two knock-in mouse models replicating de novo sequence variations in the HCN1 voltage-gated channel gene, p.G391D and p.M153I (Hcn1G380D/+ and Hcn1M142I/+ in mouse), associated with severe drug-resistant neonatal- and childhood-onset epilepsy, respectively. Heterozygous mice from both lines displayed spontaneous generalized tonic-clonic seizures. Animals replicating the p.G391D variant had an overall more severe phenotype, with pronounced alterations in the levels and distribution of HCN1 protein, including disrupted targeting to the axon terminals of basket cell interneurons. In line with clinical reports from patients with pathogenic HCN1 sequence variations, administration of the antiepileptic Na+ channel antagonists lamotrigine and phenytoin resulted in the paradoxical induction of seizures in both mouse lines, consistent with an effect to further impair inhibitory neuron function. We also show that these variants can render HCN1 channels unresponsive to classic antagonists, indicating the need to screen mutated channels to identify novel compounds with diverse mechanism of action. Our results underscore the necessity of tailoring effective therapies for specific channel gene variants, and how strongly validated animal models may provide an invaluable tool towards reaching this objective.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for Figures 2, 3, 5, 9 and 10. Microarray expression data have been deposited in GEO under accession code GSE209630.
Article and author information
Author details
Funding
National Institutes of Health (NS106983)
- Steve Siegelbaum
National Institutes of Health (NS109366)
- Steve Siegelbaum
National Institutes of Health (NS123648)
- Steve Siegelbaum
Deutsche Forschungsgemeinschaft (FOR 2715 (IS63/10-1/2))
- Dirk Isbrandt
Deutsche Forschungsgemeinschaft (CRC 1451 (project ID 431549029 - B01))
- Dirk Isbrandt
Fondazione Telethon (GGP20021)
- Anna Moroni
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: Mouse colonies were maintained both at the University of Cologne and at Columbia University (New York). For research conducted in Cologne, all experiments were in accordance with European, national and institutional guidelines and approved by the State Office of North Rhine-Westphalia, Department of Nature, Environment and Consumer Protection (LANUV NRW, Germany; reference number 81-02.04.2018.A085). For research conducted in New York, all animal experiments were conducted in accordance with policies of the NIH Guide for the Care and Use of Laboratory Animals and the Institutional Animal Care and Use Committee of Columbia University (IACUC protocols AABL5560, AABL5563, AABI2614 and AAAX6450).
Copyright
© 2022, Merseburg et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Seizures, behavioral deficits and adverse drug responses in two new genetic mouse models of HCN1 epileptic encephalopathy
eLife 11:e70826.
https://doi.org/10.7554/eLife.70826
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