title: Neurons efficiently repair glutamate-induced oxidative DNA damage by a process involving CREB-mediated up-regulation of apurinic endonuclease 1.
abstract: Glutamate, the major excitatory neurotransmitter in the brain, activates receptors coupled to membrane depolarization and Ca(2+) influx that mediates functional responses of neurons including processes such as learning and memory. Here we show that reversible nuclear oxidative DNA damage occurs in cerebral cortical neurons in response to transient glutamate receptor activation using non-toxic physiological levels of glutamate. This DNA damage was prevented by intracellular Ca(2+) chelation, the mitochondrial superoxide dismutase mimetic MnTMPyP (Mn-5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine chloride tetrakis(methochloride)), and blockade of the permeability transition pore. The repair of glutamate-induced DNA damage was associated with increased DNA repair activity and increased mRNA and protein levels of apurinic endonuclease 1 (APE1). APE1 knockdown induced accumulation of oxidative DNA damage after glutamate treatment, suggesting that APE1 is a key repair protein for glutamate-induced DNA damage. A cAMP-response element-binding protein (CREB) binding sequence is present in the Ape1 gene (encodes APE1 protein) promoter and treatment of neurons with a Ca(2+)/calmodulin-dependent kinase inhibitor (KN-93) blocked the ability of glutamate to induce CREB phosphorylation and APE1 expression. Selective depletion of CREB using RNA interference prevented glutamate-induced up-regulation of APE1. Thus, glutamate receptor stimulation triggers Ca(2+)- and mitochondrial reactive oxygen species-mediated DNA damage that is then rapidly repaired by a mechanism involving Ca(2+)-induced, CREB-mediated APE1 expression. Our findings reveal a previously unknown ability of neurons to efficiently repair oxidative DNA lesions after transient activation of glutamate receptors.
authors.affiliation: Laboratory of Molecular Gerontology, National Institute on Aging Intramural Research Program, Baltimore, Maryland 21224, USA.
authors.forename: Jenq-Lin
authors.initials: JL
authors.lastname: Yang
authors.forename: Takashi
authors.initials: T
authors.lastname: Tadokoro
authors.forename: Guido
authors.initials: G
authors.lastname: Keijzers
authors.forename: Mark P
authors.initials: MP
authors.lastname: Mattson
authors.forename: Vilhelm A
authors.initials: VA
authors.lastname: Bohr
mesh_terms: D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002540:Cerebral Cortex / Q000166:cytology; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair / Q000235:genetics*; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D018698:Glutamic Acid / Q000494:pharmacology*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000201:enzymology / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects* / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D017470:Receptors, Glutamate; D013481:Superoxides; D018698:Glutamic Acid; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase