Abstract TP276: NADPH protects post-stroke brain by activating m ⁶ A demethylase FTO

Introduction: m 6 A methylation is the most pronounced epitranscriptomic modification of RNAs. Fat mass and obesity-associated (FTO) demethylates m 6 A-modified RNAs. Stroke reduces cerebral FTO expression, leading to increased abundance of m 6 A hypermethylated RNAs. FTO overexpression with a viral vector demethylates m 6 A-modified RNAs and improves post-stroke functional recovery. As NADPH is a potent activator of FTO, we currently evaluated its therapeutic potential in a rodent stroke model. Material and Methods: Mice (adult/aged; male/female) were subjected to transient middle artery occlusion (MCAO) or photothrombotic ischemia, followed by intravenous NADPH treatment. FTO activity and m 6 A RNA methylation were measured using enzymatic assays. NADPH efficacy and therapeutic window were assessed using a battery of sensorimotor and cognitive tests. Brain infarct volume, atrophy, and white matter damage were evaluated using MRI and histology. Results: Post-stroke NADPH administration increased demethylase activity and reduced m 6 A-methylated RNA abundance without altering FTO expression. NADPH treatment promoted significant protection of grey and white matter, and better motor and cognitive recovery in both sexes, with a good therapeutic window and a low minimal efficacious dose. More importantly, FTO was also neuroprotective in aged mice subjected to stroke. Conclusion: NADPH promotes FTO-mediated m 6 A demethylation after stroke, leading to reduced brain damage and enhanced functional recovery in both sexes.