Background and Purpose—
Adenosine in many types of RNAs can be converted to m
6
A (N
6
-methyladenosine) which is a highly dynamic epitranscriptomic modification that regulates RNA metabolism and function. Of all organs, the brain shows the highest abundance of m
6
A methylation of RNAs. As recent studies showed that m
6
A modification promotes cell survival after adverse conditions, we currently evaluated the effect of stroke on cerebral m
6
A methylation in mRNAs and lncRNAs.
Methods—
Adult C57BL/6J mice were subjected to transient middle cerebral artery occlusion. In the peri-infarct cortex, m
6
A levels were measured by dot blot analysis, and transcriptome-wide m
6
A changes were profiled using immunoprecipitated methylated RNAs with microarrays (44 122 mRNAs and 12 496 lncRNAs). Gene ontology analysis was conducted to understand the functional implications of m
6
A changes after stroke. Expression of m
6
A writers, readers, and erasers was also estimated in the ischemic brain.
Results—
Global m
6
A levels increased significantly at 12 hours and 24 hours of reperfusion compared with sham. While 139 transcripts (122 mRNAs and 17 lncRNAs) were hypermethylated, 8 transcripts (5 mRNAs and 3 lncRNAs) were hypomethylated (>5-fold compared with sham) in the ischemic brain at 12 hours reperfusion. Inflammation, apoptosis, and transcriptional regulation are the major biological processes modulated by the poststroke differentially m
6
A methylated mRNAs. The m
6
A writers were unaltered, but the m
6
A eraser (fat mass and obesity-associated protein) decreased significantly after stroke compared with sham.
Conclusions—
This is the first study to show that stroke alters the cerebral m
6
A epitranscriptome, which might have functional implications in poststroke pathophysiology.
Visual Overview—
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visual overview
is available for this article.
Transient Focal Ischemia Significantly Alters the m
6
A Epitranscriptomic Tagging of RNAs in the Brain