GABAergic neuron deficit as an idiopathic generalized epilepsy mechanism: the role of BRD2 haploinsufficiency in juvenile myoclonic epilepsy.

Idiopathic generalized epilepsy (IGE) syndromes represent about 30% of all epilepsies. They have strong, but elusive, genetic components and sex-specific seizure expression. Multiple linkage and population association studies have connected the bromodomain-containing gene BRD2 to forms of IGE. In mi...

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Main Authors: Libor Velíšek, Enyuan Shang, Jana Velíšková, Tamar Chachua, Stephania Macchiarulo, Giorgi Maglakelidze, Debra J Wolgemuth, David A Greenberg
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2011-01-01
Series:PLoS ONE
Online Access:https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21887291/?tool=EBI
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author Libor Velíšek
Enyuan Shang
Jana Velíšková
Tamar Chachua
Stephania Macchiarulo
Giorgi Maglakelidze
Debra J Wolgemuth
David A Greenberg
author_facet Libor Velíšek
Enyuan Shang
Jana Velíšková
Tamar Chachua
Stephania Macchiarulo
Giorgi Maglakelidze
Debra J Wolgemuth
David A Greenberg
author_sort Libor Velíšek
collection DOAJ
description Idiopathic generalized epilepsy (IGE) syndromes represent about 30% of all epilepsies. They have strong, but elusive, genetic components and sex-specific seizure expression. Multiple linkage and population association studies have connected the bromodomain-containing gene BRD2 to forms of IGE. In mice, a null mutation at the homologous Brd2 locus results in embryonic lethality while heterozygous Brd2+/- mice are viable and overtly normal. However, using the flurothyl model, we now show, that compared to the Brd2+/+ littermates, Brd2+/- males have a decreased clonic, and females a decreased tonic-clonic, seizure threshold. Additionally, long-term EEG/video recordings captured spontaneous seizures in three out of five recorded Brd2+/- female mice. Anatomical analysis of specific regions of the brain further revealed significant differences in Brd2+/- vs +/+ mice. Specifically, there were decreases in the numbers of GABAergic (parvalbumin- or GAD67-immunopositive) neurons along the basal ganglia pathway, i.e., in the neocortex and striatum of Brd2+/- mice, compared to Brd2+/+ mice. There were also fewer GABAergic neurons in the substantia nigra reticulata (SNR), yet there was a minor, possibly compensatory increase in the GABA producing enzyme GAD67 in these SNR cells. Further, GAD67 expression in the superior colliculus and ventral medial thalamic nucleus, the main SNR outputs, was significantly decreased in Brd2+/- mice, further supporting GABA downregulation. Our data show that the non-channel-encoding, developmentally critical Brd2 gene is associated with i) sex-specific increases in seizure susceptibility, ii) the development of spontaneous seizures, and iii) seizure-related anatomical changes in the GABA system, supporting BRD2's involvement in human IGE.
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spelling doaj.art-b35688e638374321aa40bddf05b349732022-12-21T21:23:39ZengPublic Library of Science (PLoS)PLoS ONE1932-62032011-01-0168e2365610.1371/journal.pone.0023656GABAergic neuron deficit as an idiopathic generalized epilepsy mechanism: the role of BRD2 haploinsufficiency in juvenile myoclonic epilepsy.Libor VelíšekEnyuan ShangJana VelíškováTamar ChachuaStephania MacchiaruloGiorgi MaglakelidzeDebra J WolgemuthDavid A GreenbergIdiopathic generalized epilepsy (IGE) syndromes represent about 30% of all epilepsies. They have strong, but elusive, genetic components and sex-specific seizure expression. Multiple linkage and population association studies have connected the bromodomain-containing gene BRD2 to forms of IGE. In mice, a null mutation at the homologous Brd2 locus results in embryonic lethality while heterozygous Brd2+/- mice are viable and overtly normal. However, using the flurothyl model, we now show, that compared to the Brd2+/+ littermates, Brd2+/- males have a decreased clonic, and females a decreased tonic-clonic, seizure threshold. Additionally, long-term EEG/video recordings captured spontaneous seizures in three out of five recorded Brd2+/- female mice. Anatomical analysis of specific regions of the brain further revealed significant differences in Brd2+/- vs +/+ mice. Specifically, there were decreases in the numbers of GABAergic (parvalbumin- or GAD67-immunopositive) neurons along the basal ganglia pathway, i.e., in the neocortex and striatum of Brd2+/- mice, compared to Brd2+/+ mice. There were also fewer GABAergic neurons in the substantia nigra reticulata (SNR), yet there was a minor, possibly compensatory increase in the GABA producing enzyme GAD67 in these SNR cells. Further, GAD67 expression in the superior colliculus and ventral medial thalamic nucleus, the main SNR outputs, was significantly decreased in Brd2+/- mice, further supporting GABA downregulation. Our data show that the non-channel-encoding, developmentally critical Brd2 gene is associated with i) sex-specific increases in seizure susceptibility, ii) the development of spontaneous seizures, and iii) seizure-related anatomical changes in the GABA system, supporting BRD2's involvement in human IGE.https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21887291/?tool=EBI
spellingShingle Libor Velíšek
Enyuan Shang
Jana Velíšková
Tamar Chachua
Stephania Macchiarulo
Giorgi Maglakelidze
Debra J Wolgemuth
David A Greenberg
GABAergic neuron deficit as an idiopathic generalized epilepsy mechanism: the role of BRD2 haploinsufficiency in juvenile myoclonic epilepsy.
PLoS ONE
title GABAergic neuron deficit as an idiopathic generalized epilepsy mechanism: the role of BRD2 haploinsufficiency in juvenile myoclonic epilepsy.
title_full GABAergic neuron deficit as an idiopathic generalized epilepsy mechanism: the role of BRD2 haploinsufficiency in juvenile myoclonic epilepsy.
title_fullStr GABAergic neuron deficit as an idiopathic generalized epilepsy mechanism: the role of BRD2 haploinsufficiency in juvenile myoclonic epilepsy.
title_full_unstemmed GABAergic neuron deficit as an idiopathic generalized epilepsy mechanism: the role of BRD2 haploinsufficiency in juvenile myoclonic epilepsy.
title_short GABAergic neuron deficit as an idiopathic generalized epilepsy mechanism: the role of BRD2 haploinsufficiency in juvenile myoclonic epilepsy.
title_sort gabaergic neuron deficit as an idiopathic generalized epilepsy mechanism the role of brd2 haploinsufficiency in juvenile myoclonic epilepsy
url https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21887291/?tool=EBI
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