O-GlcNAc Glycosylation of nNOS Promotes Neuronal Apoptosis Following Glutamate Excitotoxicity

Ischemic stroke is a dominant health problem with extremely high rates of mortality and disability. The main mechanism of neuronal injury after stroke is excitotoxicity, during which the activation of neuronal nitric oxide synthase (nNOS) exerts a vital role. However, directly blocking N-methyl-d-aspartate receptors or nNOS can lead to severe undesirable effects since they have crucial physiological functions in the central nervous system. Here, we report that nNOS undergoes O-linked-β-N-acetylglucosamine (O-GlcNAc) modification via interacting with O-GlcNAc transferase, and the O-GlcNAcylation of nNOS remarkably increases during glutamate-induced excitotoxicity. In addition, eliminating the O-GlcNAcylation of nNOS protects neurons from apoptosis during glutamate stimulation by decreasing the formation of nNOS–postsynaptic density protein 95 complexes. Taken together, our data suggest a novel function of the O-GlcNAcylation of nNOS in neuronal apoptosis during glutamate excitotoxicity, suggesting a novel therapy strategy for ischemic stroke.