N6-methyladenosine(mA) demethylase FTO regulates cellular apoptosis following cobalt-induced oxidative stress.

Cobalt is an environmental toxicant that is known to damage human health. However, the molecular mechanisms underlying cobalt-induced neurotoxicity have not been elucidated in detail. In the present research, we used human neuroglioma H4 cells as an in vitro model. Cells were exposed to CoCl (0, 100, 200, 400 μM) for 24 h. We performed mA sequencing techniques and constructed FTO-knockdown/FTO-overexpressing cells to investigate the role of FTO-mediated mA modification in regulating apoptosis following CoCl induced oxidative stress. Our study has shown CoCl exposure led to the decrease of demethylase FTO as well as elevated oxidative stress. However, NAC treatment could partly reverse the reduction of FTO expression as well as the degree of ROS via eliminating oxidative stress. Meanwhile, MeRIP-seq and RNA-seq further revealed the potential function mA modification in regulating apoptosis. More importantly, KEGG pathway and Gene ontology (GO) analyses further elucidated that the differentially mA-modified genes were aggregated in apoptosis-related pathways. Mechanistic analysis indicated that knockdown of FTO facilitated CoCl-induced apoptosis via caspase activation and G1/S cell cycle arrest. Nevertheless, overexpression of FTO partly attenuated the increased apoptosis following CoCl exposure. More notably, we observed that FTO regulated apoptosis in an mA-dependent manner. Therefore, our findings reveal that CoCl induced ROS affected the mA modification of apoptosis-related genes by decreasing the expression of FTO, thereby resulting in the activation of apoptosis. These findings provide important insights into CoCl-induced apoptosis and mA modification and propose a novel strategy for studying environmental toxicant-related neurodegeneration.