Epigenetic changes induced by adenosine augmentation therapy prevent epileptogenesis
Rebecca L. Williams-Karnesky, … , David L. Kaplan, Detlev Boison
Rebecca L. Williams-Karnesky, … , David L. Kaplan, Detlev Boison
Published July 25, 2013
Citation Information: J Clin Invest. 2013;123(8):3552-3563. https://doi.org/10.1172/JCI65636.
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Research Article Neuroscience

Epigenetic changes induced by adenosine augmentation therapy prevent epileptogenesis

Abstract

Epigenetic modifications, including changes in DNA methylation, lead to altered gene expression and thus may underlie epileptogenesis via induction of permanent changes in neuronal excitability. Therapies that could inhibit or reverse these changes may be highly effective in halting disease progression. Here we identify an epigenetic function of the brain’s endogenous anticonvulsant adenosine, showing that this compound induces hypomethylation of DNA via biochemical interference with the transmethylation pathway. We show that inhibition of DNA methylation inhibited epileptogenesis in multiple seizure models. Using a rat model of temporal lobe epilepsy, we identified an increase in hippocampal DNA methylation, which correlates with increased DNA methyltransferase activity, disruption of adenosine homeostasis, and spontaneous recurrent seizures. Finally, we used bioengineered silk implants to deliver a defined dose of adenosine over 10 days to the brains of epileptic rats. This transient therapeutic intervention reversed the DNA hypermethylation seen in the epileptic brain, inhibited sprouting of mossy fibers in the hippocampus, and prevented the progression of epilepsy for at least 3 months. These data demonstrate that pathological changes in DNA methylation homeostasis may underlie epileptogenesis and reversal of these epigenetic changes with adenosine augmentation therapy may halt disease progression.

Authors

Rebecca L. Williams-Karnesky, Ursula S. Sandau, Theresa A. Lusardi, Nikki K. Lytle, Joseph M. Farrell, Eleanor M. Pritchard, David L. Kaplan, Detlev Boison

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Figure 7

ADO treatment reduces genomic DNA CpG methylation in the epileptic hippocampus.

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ADO treatment reduces genomic DNA CpG methylation in the epileptic hippo...
Analysis of bisulfite sequencing of hippocampal DNA from epileptic and ADO-treated epileptic rats confirms that predictions from the MeDIP array are translated to changes in the methylation status of CpGs. Bisulfite sequencing was performed on DNA extracts from KA9wk and KA9wk/ADO5d vs. KA9wk rats (n = 3 animals/treatment and 4–5 clones/animal). The methylation status of individual probes, which contain only 1 CpG and which span a dSLR range from –0.92 to –3.55 KA9wk/ADO5d vs. KA9wk was compared between treatment groups. Changes in methylation are displayed as percentage of methylated (pie chart, black corresponds to the percentage of methylated CpGs; 1 CpG per probe; 12 to 15 clones total) and in the representative sequence traces with methylated cytosines retained (blue peaks) and unmethylated cytosines converted to thymine (pink peaks). Note that at a KA9wk/ADO5d vs. KA9wk dSLR threshold of less than –3.0, there is a robust decrease (33%) in ADO-mediated CpG methylation in 3 out of 3 animals. Probes with a dSLR greater then a –3.0 threshold (–0.92 to –2.54) yielded only slight variations (8%) in the methylation status.