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Nat Med. 2017 Nov;23(11):1377-1383. doi: 10.1038/nm.4413. Epub 2017 Oct 16.

Epigenetic suppression of hippocampal calbindin-D28k by ΔFosB drives seizure-related cognitive deficits.

Author information

1
Department of Neuroscience and Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
2
Memory & Brain Research Center, Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA.
3
Department of Neuroscience and Physiology and Department of Psychiatry, New York University School of Medicine, New York, New York, USA.
4
Department of Pathology, Texas Children's Hospital and Baylor College of Medicine, Houston, Texas, USA.
5
Department of Neurosurgery, Baylor College of Medicine, Houston, Texas, USA.
6
Department of Neurosciences, University of California San Diego School of Medicine, La Jolla, California, USA.
7
VA San Diego Healthcare System, San Diego, California, USA.
8
Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.

Abstract

The calcium-binding protein calbindin-D28k is critical for hippocampal function and cognition, but its expression is markedly decreased in various neurological disorders associated with epileptiform activity and seizures. In Alzheimer's disease (AD) and epilepsy, both of which are accompanied by recurrent seizures, the severity of cognitive deficits reflects the degree of calbindin reduction in the hippocampal dentate gyrus (DG). However, despite the importance of calbindin in both neuronal physiology and pathology, the regulatory mechanisms that control its expression in the hippocampus are poorly understood. Here we report an epigenetic mechanism through which seizures chronically suppress hippocampal calbindin expression and impair cognition. We demonstrate that ΔFosB, a highly stable transcription factor, is induced in the hippocampus in mouse models of AD and seizures, in which it binds and triggers histone deacetylation at the promoter of the calbindin gene (Calb1) and downregulates Calb1 transcription. Notably, increasing DG calbindin levels, either by direct virus-mediated expression or inhibition of ΔFosB signaling, improves spatial memory in a mouse model of AD. Moreover, levels of ΔFosB and calbindin expression are inversely related in the DG of individuals with temporal lobe epilepsy (TLE) or AD and correlate with performance on the Mini-Mental State Examination (MMSE). We propose that chronic suppression of calbindin by ΔFosB is one mechanism through which intermittent seizures drive persistent cognitive deficits in conditions accompanied by recurrent seizures.

PMID:
29035369
PMCID:
PMC5747956
DOI:
10.1038/nm.4413
[Indexed for MEDLINE]
Free PMC Article

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