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Dis Model Mech. 2017 Nov 1;10(11):1333-1342. doi: 10.1242/dmm.029678. Epub 2017 Oct 18.

Pumilio2-deficient mice show a predisposition for epilepsy.

Author information

1
Biomedical Center (BMC), Department for Cell Biology, Faculty of Medicine, LMU, Munich, 82152 Planegg-Martinsried, Germany.
2
Biomedical Center (BMC), Department of Physiological Genomics, Ludwig-Maximilians-University, Munich, 82152 Planegg-Martinsried, Germany.
3
Biomedical Center (BMC), Core Facility Bioinformatics, Ludwig-Maximilians-University, Munich, 82152 Planegg-Martinsried, Germany.
4
Biomedical Center (BMC), Core Facility Bioimaging, Ludwig-Maximilians-University, Munich, 82152 Planegg-Martinsried, Germany.
5
Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-University, 81377 Munich, Germany.
6
Department of Laboratory Medicine and Core Facility Genomics, Medical University of Vienna, 1090 Vienna, Austria.
7
Biomedical Center (BMC), Department for Cell Biology, Faculty of Medicine, LMU, Munich, 82152 Planegg-Martinsried, Germany bastian.popper@med.uni-muenchen.de mkiebler@lmu.de.
8
Biomedical Center (BMC), Core Facility Animal Models, Ludwig-Maximilians-University, Munich, 82152 Planegg-Martinsried, Germany.

Abstract

Epilepsy is a neurological disease that is caused by abnormal hypersynchronous activities of neuronal ensembles leading to recurrent and spontaneous seizures in human patients. Enhanced neuronal excitability and a high level of synchrony between neurons seem to trigger these spontaneous seizures. The molecular mechanisms, however, regarding the development of neuronal hyperexcitability and maintenance of epilepsy are still poorly understood. Here, we show that pumilio RNA-binding family member 2 (Pumilio2; Pum2) plays a role in the regulation of excitability in hippocampal neurons of weaned and 5-month-old male mice. Almost complete deficiency of Pum2 in adult Pum2 gene-trap mice (Pum2 GT) causes misregulation of genes involved in neuronal excitability control. Interestingly, this finding is accompanied by the development of spontaneous epileptic seizures in Pum2 GT mice. Furthermore, we detect an age-dependent increase in Scn1a (Nav1.1) and Scn8a (Nav1.6) mRNA levels together with a decrease in Scn2a (Nav1.2) transcript levels in weaned Pum2 GT that is absent in older mice. Moreover, field recordings of CA1 pyramidal neurons show a tendency towards a reduced paired-pulse inhibition after stimulation of the Schaffer-collateral-commissural pathway in Pum2 GT mice, indicating a predisposition to the development of spontaneous seizures at later stages. With the onset of spontaneous seizures at the age of 5 months, we detect increased protein levels of Nav1.1 and Nav1.2 as well as decreased protein levels of Nav1.6 in those mice. In addition, GABA receptor subunit alpha-2 (Gabra2) mRNA levels are increased in weaned and adult mice. Furthermore, we observe an enhanced GABRA2 protein level in the dendritic field of the CA1 subregion in the Pum2 GT hippocampus. We conclude that altered expression levels of known epileptic risk factors such as Nav1.1, Nav1.2, Nav1.6 and GABRA2 result in enhanced seizure susceptibility and manifestation of epilepsy in the hippocampus. Thus, our results argue for a role of Pum2 in epileptogenesis and the maintenance of epilepsy.

KEYWORDS:

Epilepsy; Epileptogenesis; PUM2; Pumilio2; RNA-binding protein; Risk factor

PMID:
29046322
PMCID:
PMC5719250
DOI:
10.1242/dmm.029678
[Indexed for MEDLINE]
Free PMC Article

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