Excitatory and inhibitory neuron defects in a mouse model of Scn1b‐linked EIEE52
Abstract Objective Human variants in voltage‐gated sodium channel (VGSC) α and β subunit genes are linked to developmental and epileptic encephalopathies (DEEs). Inherited, biallelic, loss‐of‐function variants in SCN1B, encoding the β1/β1B subunits, are linked to early infantile DEE (EIEE52). De nov...
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doaj-34e03d65f7274edcbd5c7e01362639572021-05-03T01:03:44ZengWileyAnnals of Clinical and Translational Neurology2328-95032020-11-017112137214910.1002/acn3.51205Excitatory and inhibitory neuron defects in a mouse model of Scn1b‐linked EIEE52Jacob M. Hull0Heather A. O’MalleyChunling Chen1Yukun Yuan2Nicholas Denomme3Alexandra A. Bouza4Charles Anumonwo5Luis F. Lopez‐Santiago6Lori L. Isom7Neuroscience Graduate Program University of Michigan Medical School Ann Arbor MI48109USADepartment of Pharmacology University of Michigan Medical School Ann Arbor MI48109USADepartment of Pharmacology University of Michigan Medical School Ann Arbor MI48109USADepartment of Pharmacology University of Michigan Medical School Ann Arbor MI48109USADepartment of Pharmacology University of Michigan Medical School Ann Arbor MI48109USADepartment of Pharmacology University of Michigan Medical School Ann Arbor MI48109USADepartment of Pharmacology University of Michigan Medical School Ann Arbor MI48109USANeuroscience Graduate Program University of Michigan Medical School Ann Arbor MI48109USAAbstract Objective Human variants in voltage‐gated sodium channel (VGSC) α and β subunit genes are linked to developmental and epileptic encephalopathies (DEEs). Inherited, biallelic, loss‐of‐function variants in SCN1B, encoding the β1/β1B subunits, are linked to early infantile DEE (EIEE52). De novo, monoallelic variants in SCN1A (Nav1.1), SCN2A (Nav1.2), SCN3A (Nav1.3), and SCN8A (Nav1.6) are also linked to DEEs. While these VGSC‐linked DEEs have similar presentations, they have diverse mechanisms of altered neuronal excitability. Mouse models have suggested that Scn2a‐, Scn3a‐, and Scn8a‐linked DEE variants are, in general, gain of function, resulting in increased persistent or resurgent sodium current (INa) and pyramidal neuron hyperexcitability. In contrast, Scn1a‐linked DEE variants, in general, are loss‐of‐function, resulting in decreased INa and hypoexcitability of fast‐spiking interneurons. VGSC β1 subunits associate with Nav1.1, Nav1.2, Nav1.3, and Nav1.6 and are expressed throughout the brain, raising the possibility that insults to both pyramidal and interneuron excitability may drive EIEE52 pathophysiology. Methods We investigated excitability defects in pyramidal and parvalbumin‐positive (PV +) interneurons in the Scn1b−/− model of EIEE52. We also used Scn1bFL/FL mice to delete Scn1b in specific neuronal populations. Results Scn1b−/− cortical PV + interneurons were hypoexcitable, with reduced INa density. Scn1b−/− cortical pyramidal neurons had population‐specific changes in excitability and impaired INa density. Scn1b deletion in PV + neurons resulted in 100% lethality, whereas deletion in Emx1 + or Camk2a + neurons did not affect survival. Interpretation This work suggests that SCN1B‐linked DEE variants impact both excitatory and inhibitory neurons, leading to the increased severity of EIEE52 relative to other DEEs.https://doi.org/10.1002/acn3.51205 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Jacob M. Hull Heather A. O’Malley Chunling Chen Yukun Yuan Nicholas Denomme Alexandra A. Bouza Charles Anumonwo Luis F. Lopez‐Santiago Lori L. Isom |
spellingShingle |
Jacob M. Hull Heather A. O’Malley Chunling Chen Yukun Yuan Nicholas Denomme Alexandra A. Bouza Charles Anumonwo Luis F. Lopez‐Santiago Lori L. Isom Excitatory and inhibitory neuron defects in a mouse model of Scn1b‐linked EIEE52 Annals of Clinical and Translational Neurology |
author_facet |
Jacob M. Hull Heather A. O’Malley Chunling Chen Yukun Yuan Nicholas Denomme Alexandra A. Bouza Charles Anumonwo Luis F. Lopez‐Santiago Lori L. Isom |
author_sort |
Jacob M. Hull |
title |
Excitatory and inhibitory neuron defects in a mouse model of Scn1b‐linked EIEE52 |
title_short |
Excitatory and inhibitory neuron defects in a mouse model of Scn1b‐linked EIEE52 |
title_full |
Excitatory and inhibitory neuron defects in a mouse model of Scn1b‐linked EIEE52 |
title_fullStr |
Excitatory and inhibitory neuron defects in a mouse model of Scn1b‐linked EIEE52 |
title_full_unstemmed |
Excitatory and inhibitory neuron defects in a mouse model of Scn1b‐linked EIEE52 |
title_sort |
excitatory and inhibitory neuron defects in a mouse model of scn1b‐linked eiee52 |
publisher |
Wiley |
series |
Annals of Clinical and Translational Neurology |
issn |
2328-9503 |
publishDate |
2020-11-01 |
description |
Abstract Objective Human variants in voltage‐gated sodium channel (VGSC) α and β subunit genes are linked to developmental and epileptic encephalopathies (DEEs). Inherited, biallelic, loss‐of‐function variants in SCN1B, encoding the β1/β1B subunits, are linked to early infantile DEE (EIEE52). De novo, monoallelic variants in SCN1A (Nav1.1), SCN2A (Nav1.2), SCN3A (Nav1.3), and SCN8A (Nav1.6) are also linked to DEEs. While these VGSC‐linked DEEs have similar presentations, they have diverse mechanisms of altered neuronal excitability. Mouse models have suggested that Scn2a‐, Scn3a‐, and Scn8a‐linked DEE variants are, in general, gain of function, resulting in increased persistent or resurgent sodium current (INa) and pyramidal neuron hyperexcitability. In contrast, Scn1a‐linked DEE variants, in general, are loss‐of‐function, resulting in decreased INa and hypoexcitability of fast‐spiking interneurons. VGSC β1 subunits associate with Nav1.1, Nav1.2, Nav1.3, and Nav1.6 and are expressed throughout the brain, raising the possibility that insults to both pyramidal and interneuron excitability may drive EIEE52 pathophysiology. Methods We investigated excitability defects in pyramidal and parvalbumin‐positive (PV +) interneurons in the Scn1b−/− model of EIEE52. We also used Scn1bFL/FL mice to delete Scn1b in specific neuronal populations. Results Scn1b−/− cortical PV + interneurons were hypoexcitable, with reduced INa density. Scn1b−/− cortical pyramidal neurons had population‐specific changes in excitability and impaired INa density. Scn1b deletion in PV + neurons resulted in 100% lethality, whereas deletion in Emx1 + or Camk2a + neurons did not affect survival. Interpretation This work suggests that SCN1B‐linked DEE variants impact both excitatory and inhibitory neurons, leading to the increased severity of EIEE52 relative to other DEEs. |
url |
https://doi.org/10.1002/acn3.51205 |
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