N6-methyladenine DNA demethylase ALKBH1 regulates mammalian axon regeneration

Recent studies have shown that DNA N6-methyladenine (N6-mA) modification is emerging to be a novel and important epigenetic regulator of mammalian gene transcription. Several studies demonstrated DNA N6-mA in human or rodents was regulated by methyltransferase N6AMT1 and demethylase ALKBH1. Moreover, studies in mouse brain or human glioblastoma cells showed that reduced level of N6-mA or higher level of ALKBH1 was correlated with up regulated levels of genes associated with neuronal development. We thus investigated the functional roles of ALKBH1 in sensory axon regeneration. Our results showed that ALKBH1 regulated the level of N6-mA in sensory neurons, and upon peripheral nerve injury ALKBH1 was up regulated in mouse sensory neurons. Functionally, knocking down ALKBH1 in sensory neurons resulted in reduced axon regeneration in vitro and in vivo, which could be rescued by simultaneously knocking down N6AMT1. Moreover, knocking down ALKBH1 led to decreased levels of many neurodevelopment regulatory genes, including neuritin that is well known to enhance axon growth and regeneration. Our study not only revealed a novel physiological function of DNA N6-mA, but also identified a new epigenetic mechanism regulating mammalian axon regeneration. Significance StatementThe study demonstrated that DNA N6-methyladenine (N6-mA) modification played important roles in regulation of sensory axon regeneration, likely through controlling the expression of neurodevelopmental associated genes. The results will add new evidence about the physiological function of DNA N6-mA and its regulatory demethylase ALKBH1 in neurons.