Levetiracetam resistance: Synaptic signatures &amp; corresponding promoter SNPs in epileptic hippocampi

Tanja Grimminger; Katharina Pernhorst; Rainer Surges; Pitt Niehusmann; Lutz Priebe; Marec von Lehe; Per Hoffmann; Sven Cichon; Susanne Schoch; Albert J. Becker

Neurobiology of Disease (Dec 2013)

Levetiracetam resistance: Synaptic signatures & corresponding promoter SNPs in epileptic hippocampi

Tanja Grimminger,
Katharina Pernhorst,
Rainer Surges,
Pitt Niehusmann,
Lutz Priebe,
Marec von Lehe,
Per Hoffmann,
Sven Cichon,
Susanne Schoch,
Albert J. Becker

Affiliations

Tanja Grimminger: Dept. of Neuropathology, University of Bonn Medical Center, Germany
Katharina Pernhorst: Dept. of Neuropathology, University of Bonn Medical Center, Germany
Rainer Surges: Dept. of Epileptology, University of Bonn Medical Center, Germany
Pitt Niehusmann: Dept. of Neuropathology, University of Bonn Medical Center, Germany
Lutz Priebe: Institute of Human Genetics, Platform Genomics, Life and Brain Center, University of Bonn Medical Center, Germany
Marec von Lehe: Dept. of Neurosurgery, University of Bonn Medical Center, Germany
Per Hoffmann: Institute of Human Genetics, Platform Genomics, Life and Brain Center, University of Bonn Medical Center, Germany; Division of Medical Genetics, University Hospital Basel, Department of Biomedicine, University of Basel, Switzerland; Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Germany
Sven Cichon: Institute of Human Genetics, Platform Genomics, Life and Brain Center, University of Bonn Medical Center, Germany; Division of Medical Genetics, University Hospital Basel, Department of Biomedicine, University of Basel, Switzerland; Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Germany
Susanne Schoch: Dept. of Neuropathology, University of Bonn Medical Center, Germany
Albert J. Becker: Dept. of Neuropathology, University of Bonn Medical Center, Germany; Corresponding author at: Department of Neuropathology, University of Bonn Medical Center, Sigmund-Freud Str. 25, D-53105 Bonn, Germany. Fax: +49 228 287 14331.

Journal volume & issue: Vol. 60
pp. 115 – 125

Abstract

Read online

Pharmacoresistance to antiepileptic drugs (AEDs) is a major clinical problem in patients with mesial temporal lobe epilepsy (mTLE). Levetiracetam (LEV) represents a unique type of AED as its high-affinity binding site, the synaptic vesicle protein SV2A, is a component of the presynaptic release machinery. LEV often leads to full seizure control even in previously refractory patients. However, approximately 30% of LEV-treated mTLE patients do not show a significant response to LEV from the beginning of the pharmacotherapy and are therefore classified as a priori non-responders. This unexpected phenomenon prompted genetic studies, which failed to characterize responsible SV2A sequence alterations.Here, we followed a different approach to study the mechanisms of LEV pharmacoresistance by screening for mRNA signatures specifically expressed in LEV a priori non-responders in epileptic brain tissue and subsequent promoter analyses of highly altered transcripts. To this end, we have used our unique access to analyze hippocampal tissue from pharmacoresistant TLE patients who underwent epilepsy surgery for seizure control (n = 53) stratified according to a priori LEV responders versus patients with impaired LEV-response. Transcriptome (Illumina platform) and subsequent multimodal cluster analyses uncovered strikingly abundant synapse-associated molecule mRNA signatures in LEV a priori non-responders. Subsequent promoter characterization revealed accumulation of the single nucleotide polymorphism (SNP) rs9305614 G-allele in a priori non-responders to correlate to abundant mRNAs of phosphatidylinositol N-acetylglucosaminyltransferase (PIGP), i.e. a key component of the Wnt-signaling pathway. By luciferase assays, we observed significantly stronger activation by the LBP-1 transcription factor of the rs9305614 G-allele PIGP promoter. The present data suggest an abundance of transcripts encoding for key synaptic components in the hippocampi of LEV a priori non-responder mTLE patients, which for PIGP as proof of concept can be explained by a particular promoter variant. Our data argue for epigenetic factors predisposing for a priori LEV pharmacoresistance by transcriptional ‘overexposure of targets’.

Published in Neurobiology of Disease

ISSN: 0969-9961 (Print); 1095-953X (Online)
Publisher: Elsevier
Country of publisher: United States
LCC subjects: Medicine: Internal medicine: Neurosciences. Biological psychiatry. Neuropsychiatry
Website: https://www.journals.elsevier.com/neurobiology-of-disease

About the journal

Abstract

Keywords