Decreased epileptogenesis in mice lacking the System x c transporter occurs in association with a reduction in AMPA receptor subunit GluA1

Sheila M.S. Sears, James Hewett, Sandra Hewett

Research output: Contribution to journalArticle

Abstract

Objective: Although the cystine/glutamate antiporter System x c (Sx c ) plays a permissive role in glioma-associated seizures, its contribution to other acquired epilepsies has not been determined. As such, the present study investigates whether and how Sx c contributes to the pentylenetetrazole (PTZ) chemical kindling model of epileptogenesis. Methods: Male Sx c null (sut/sut) mice and their wild-type littermates were administered PTZ (i.p.) daily for up to 21 days (kindling paradigm). Seizure severity was scored on a 5-point behavioral scale. Mossy fiber sprouting, cellular degeneration, and Sx c light chain (xCT) messenger RNA (mRNA) were explored using Timm staining, thionin staining, and real-time quantitative polymerase chain reaction (qPCR), respectively. Levels of reduced and oxidized glutathione and cysteine were determined via high-performance liquid chromatography (HPLC). Plasma membrane protein levels of glutamate and γ-aminobutyric acid (GABA) receptor subunits as well as the K + /Cl co-transporter KCC2 were quantified via western blot analysis. Results: Repeated administration of PTZ produced chemical kindling in only 50% of Sx c null mice as compared to 82% of wild-type littermate control mice. Kindling did not result in any changes in xCT mRNA levels assessed in wild-type mice. No cellular degeneration or mossy fiber sprouting was discernible in either genotype. Except for a small, but significant, decrease in oxidized cysteine in the hippocampus, no other change in measured redox couples was determined in Sx c null mice. Cortical levels of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluA1 were decreased in Sx c null mice as compared to wild-type littermates, whereas all other proteins tested showed no difference between genotypes. Significance: This study provides the first evidence that Sx c signaling contributes to epileptogenesis in the PTZ kindling model of acquired epilepsy. Further data indicate that a reduction in AMPA receptor signaling could underlie the resistance to PTZ kindling uncovered in Sx c null mice.

Original languageEnglish (US)
Pages (from-to)133-143
Number of pages11
JournalEpilepsia Open
Volume4
Issue number1
DOIs
StatePublished - Mar 1 2019

Fingerprint

AMPA Receptors
Pentylenetetrazole
Cysteine
Glutamic Acid
Epilepsy
Seizures
Thionins
Genotype
Staining and Labeling
Chemical Models
Aminobutyrates
Antiporters
Symporters
Messenger RNA
Cystine
Glutathione Disulfide
Glioma
Oxidation-Reduction
Glutathione
Blood Proteins

Keywords

  • astrocytes
  • GluA1
  • kindling
  • pentylenetetrazole
  • xCT

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology

Cite this

@article{e3982ac296b149d0b1103edf8e931ec3,
title = "Decreased epileptogenesis in mice lacking the System x c − transporter occurs in association with a reduction in AMPA receptor subunit GluA1",
abstract = "Objective: Although the cystine/glutamate antiporter System x c − (Sx c − ) plays a permissive role in glioma-associated seizures, its contribution to other acquired epilepsies has not been determined. As such, the present study investigates whether and how Sx c − contributes to the pentylenetetrazole (PTZ) chemical kindling model of epileptogenesis. Methods: Male Sx c − null (sut/sut) mice and their wild-type littermates were administered PTZ (i.p.) daily for up to 21 days (kindling paradigm). Seizure severity was scored on a 5-point behavioral scale. Mossy fiber sprouting, cellular degeneration, and Sx c − light chain (xCT) messenger RNA (mRNA) were explored using Timm staining, thionin staining, and real-time quantitative polymerase chain reaction (qPCR), respectively. Levels of reduced and oxidized glutathione and cysteine were determined via high-performance liquid chromatography (HPLC). Plasma membrane protein levels of glutamate and γ-aminobutyric acid (GABA) receptor subunits as well as the K + /Cl − co-transporter KCC2 were quantified via western blot analysis. Results: Repeated administration of PTZ produced chemical kindling in only 50{\%} of Sx c − null mice as compared to 82{\%} of wild-type littermate control mice. Kindling did not result in any changes in xCT mRNA levels assessed in wild-type mice. No cellular degeneration or mossy fiber sprouting was discernible in either genotype. Except for a small, but significant, decrease in oxidized cysteine in the hippocampus, no other change in measured redox couples was determined in Sx c − null mice. Cortical levels of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluA1 were decreased in Sx c − null mice as compared to wild-type littermates, whereas all other proteins tested showed no difference between genotypes. Significance: This study provides the first evidence that Sx c − signaling contributes to epileptogenesis in the PTZ kindling model of acquired epilepsy. Further data indicate that a reduction in AMPA receptor signaling could underlie the resistance to PTZ kindling uncovered in Sx c − null mice.",
keywords = "astrocytes, GluA1, kindling, pentylenetetrazole, xCT",
author = "Sears, {Sheila M.S.} and James Hewett and Sandra Hewett",
year = "2019",
month = "3",
day = "1",
doi = "10.1002/epi4.12307",
language = "English (US)",
volume = "4",
pages = "133--143",
journal = "Epilepsia Open",
issn = "2470-9239",
publisher = "Wiley-Blackwell Publishing Ltd",
number = "1",

}

TY - JOUR

T1 - Decreased epileptogenesis in mice lacking the System x c − transporter occurs in association with a reduction in AMPA receptor subunit GluA1

AU - Sears, Sheila M.S.

AU - Hewett, James

AU - Hewett, Sandra

PY - 2019/3/1

Y1 - 2019/3/1

N2 - Objective: Although the cystine/glutamate antiporter System x c − (Sx c − ) plays a permissive role in glioma-associated seizures, its contribution to other acquired epilepsies has not been determined. As such, the present study investigates whether and how Sx c − contributes to the pentylenetetrazole (PTZ) chemical kindling model of epileptogenesis. Methods: Male Sx c − null (sut/sut) mice and their wild-type littermates were administered PTZ (i.p.) daily for up to 21 days (kindling paradigm). Seizure severity was scored on a 5-point behavioral scale. Mossy fiber sprouting, cellular degeneration, and Sx c − light chain (xCT) messenger RNA (mRNA) were explored using Timm staining, thionin staining, and real-time quantitative polymerase chain reaction (qPCR), respectively. Levels of reduced and oxidized glutathione and cysteine were determined via high-performance liquid chromatography (HPLC). Plasma membrane protein levels of glutamate and γ-aminobutyric acid (GABA) receptor subunits as well as the K + /Cl − co-transporter KCC2 were quantified via western blot analysis. Results: Repeated administration of PTZ produced chemical kindling in only 50% of Sx c − null mice as compared to 82% of wild-type littermate control mice. Kindling did not result in any changes in xCT mRNA levels assessed in wild-type mice. No cellular degeneration or mossy fiber sprouting was discernible in either genotype. Except for a small, but significant, decrease in oxidized cysteine in the hippocampus, no other change in measured redox couples was determined in Sx c − null mice. Cortical levels of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluA1 were decreased in Sx c − null mice as compared to wild-type littermates, whereas all other proteins tested showed no difference between genotypes. Significance: This study provides the first evidence that Sx c − signaling contributes to epileptogenesis in the PTZ kindling model of acquired epilepsy. Further data indicate that a reduction in AMPA receptor signaling could underlie the resistance to PTZ kindling uncovered in Sx c − null mice.

AB - Objective: Although the cystine/glutamate antiporter System x c − (Sx c − ) plays a permissive role in glioma-associated seizures, its contribution to other acquired epilepsies has not been determined. As such, the present study investigates whether and how Sx c − contributes to the pentylenetetrazole (PTZ) chemical kindling model of epileptogenesis. Methods: Male Sx c − null (sut/sut) mice and their wild-type littermates were administered PTZ (i.p.) daily for up to 21 days (kindling paradigm). Seizure severity was scored on a 5-point behavioral scale. Mossy fiber sprouting, cellular degeneration, and Sx c − light chain (xCT) messenger RNA (mRNA) were explored using Timm staining, thionin staining, and real-time quantitative polymerase chain reaction (qPCR), respectively. Levels of reduced and oxidized glutathione and cysteine were determined via high-performance liquid chromatography (HPLC). Plasma membrane protein levels of glutamate and γ-aminobutyric acid (GABA) receptor subunits as well as the K + /Cl − co-transporter KCC2 were quantified via western blot analysis. Results: Repeated administration of PTZ produced chemical kindling in only 50% of Sx c − null mice as compared to 82% of wild-type littermate control mice. Kindling did not result in any changes in xCT mRNA levels assessed in wild-type mice. No cellular degeneration or mossy fiber sprouting was discernible in either genotype. Except for a small, but significant, decrease in oxidized cysteine in the hippocampus, no other change in measured redox couples was determined in Sx c − null mice. Cortical levels of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluA1 were decreased in Sx c − null mice as compared to wild-type littermates, whereas all other proteins tested showed no difference between genotypes. Significance: This study provides the first evidence that Sx c − signaling contributes to epileptogenesis in the PTZ kindling model of acquired epilepsy. Further data indicate that a reduction in AMPA receptor signaling could underlie the resistance to PTZ kindling uncovered in Sx c − null mice.

KW - astrocytes

KW - GluA1

KW - kindling

KW - pentylenetetrazole

KW - xCT

UR - http://www.scopus.com/inward/record.url?scp=85062420414&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85062420414&partnerID=8YFLogxK

U2 - 10.1002/epi4.12307

DO - 10.1002/epi4.12307

M3 - Article

AN - SCOPUS:85062420414

VL - 4

SP - 133

EP - 143

JO - Epilepsia Open

JF - Epilepsia Open

SN - 2470-9239

IS - 1

ER -