NADPH Enhances FTO-mediated N6-methyladenosine Demethylation

Fat mass and obesity-associated protein (FTO) is well known to associate with obesity and to remove N6-methyladenosine (m6A) methylation. However, little is known about the regulatory mechanisms of FTO in response to the metabolic environments. Here, we show that NADPH directly binds FTO, increases FTO-mediated m6A oxidation, and enhances adipogenesis. To identify the candidate metabolite(s) directly binding FTO, we applied metabolite affinity responsive target fluorescence quenching (MARTFQ) to screen a set of obesity related metabolites. The MARTFQ assay is based on the biophysical principle of ligand-induced intrinsic fluorescence quenching of target proteins. Using MARTFQ, we identified NADPH showing the most remarkable ability to bind FTO. Further analyses indicated that solo NADPH showed more significant ability than ascorbic acid (VC) to facilitate FTO to demethylate m6A. And increase of NADPH could enhance adipogenesis through the regulation of FTO activity. These results shed light on the regulatory mechanism of m6A in response to metabolic environments.