Cobalt induces neurodegeneration through FTO-triggered autophagy impairment by targeting TSC1 in an m6A-YTHDF2-dependent manner

Cobalt is the most widely used heavy metal pollutant in medicine and industry. Excessive cobalt exposure can adversely affect human health. Neurodegenerative symptoms have been observed in cobalt-exposed populations; however, the underlying mechanisms remain largely unknown. In this study, we demonstrate that the N6-methyladenosine (m6A) demethylase fat mass and obesity-associated gene (FTO) mediates cobalt-induced neurodegeneration by impairing autophagic flux. Cobalt-induced neurodegeneration was exacerbated through FTO genetic knockdown or repression of demethylase activity, but was alleviated by FTO overexpression. Mechanistically, we showed that FTO regulates TSC1/2-mTOR signaling pathway by targeting TSC1 mRNA stability in an m6A-YTHDF2 manner, which resulted in autophagosome accumulation. Furthermore, FTO decreases lysosome-associated membrane protein-2 (LAMP2) to inhibit the integration of autophagosomes and lysosomes, leading to autophagic flux damage. In vivo experiments further identified that central nervous system (CNS)-Fto-specific knockout resulted in serious neurobehavioral and pathological damage as well as TSC1-related autophagy impairment in cobalt-exposed mice. Interestingly, FTO-regulated autophagy impairment has been confirmed in patients with hip replacement. Collectively, our results provide novel insights into m6A-modulated autophagy through FTO-YTHDF2 targeted TSC1 mRNA stability, revealing cobalt is a novel epigenetic hazard that induces neurodegeneration. These findings suggest the potential therapeutic targets for hip replacement in patients with neurodegenerative damage.