title: Enhanced expression of WD repeat-containing protein 35 (WDR35) stimulated by domoic acid in rat hippocampus: involvement of reactive oxygen species generation and p38 mitogen-activated protein kinase activation.
abstract: BACKGROUND
  Domoic acid (DA) is an excitatory amino acid analogue of kainic acid (KA) that acts via activation of glutamate receptors to elicit a rapid and potent excitotoxic response, resulting in neuronal cell death. Recently, DA was shown to elicit reactive oxygen species (ROS) production and induce apoptosis accompanied by activation of p38 mitogen-activated protein kinase (MAPK) in vitro. We have reported that WDR35, a WD-repeat protein, may mediate apoptosis in several animal models. In the present study, we administered DA to rats intraperitoneally, then used liquid chromatography/ion trap tandem mass spectrometry (LC-MS/MS) to identify and quantify DA in the brains of the rats and performed histological examinations of the hippocampus. We further investigated the potential involvement of glutamate receptors, ROS, p38 MAPK, and WDR35 in DA-induced toxicity in vivo.
  
  
  RESULTS
  Our results showed that intraperitoneally administered DA was present in the brain and induced neurodegenerative changes including apoptosis in the CA1 region of the hippocampus. DA also increased the expression of WDR35 mRNA and protein in a dose- and time-dependent manner in the hippocampus. In experiments using glutamate receptor antagonists, the AMPA/KA receptor antagonist NBQX significantly attenuated the DA-induced increase in WDR35 protein expression, but the NMDA receptor antagonist MK-801 did not. In addition, the radical scavenger edaravone significantly attenuated the DA-induced increase in WDR35 protein expression. Furthermore, NBQX and edaravone significantly attenuated the DA-induced increase in p38 MAPK phosphorylation.
  
  
  CONCLUSIONS
  In summary, our results indicated that DA activated AMPA/KA receptors and induced ROS production and p38 MAPK phosphorylation, resulting in an increase in the expression of WDR35 in vivo.
authors.affiliation: Department of Pharmacology, Aichi Medical University School of Medicine, Nagakute, Aichi, Japan. evrv@aichi-med-u.ac.jp
authors.forename: Koji
authors.initials: K
authors.lastname: Tsunekawa
authors.forename: Fumio
authors.initials: F
authors.lastname: Kondo
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Okada
authors.forename: Guo-Gang
authors.initials: GG
authors.lastname: Feng
authors.forename: Lei
authors.initials: L
authors.lastname: Huang
authors.forename: Naohisa
authors.initials: N
authors.lastname: Ishikawa
authors.forename: Shoshiro
authors.initials: S
authors.lastname: Okada
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism*; D020287:In Situ Nick-End Labeling; D007608:Kainic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D008297:Male; D009467:Neuromuscular Depolarizing Agents / Q000494:pharmacology*; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020449:Repetitive Sequences, Amino Acid / Q000235:genetics*; D053719:Tandem Mass Spectrometry
chemical_list: D018691:Excitatory Amino Acid Antagonists; D009467:Neuromuscular Depolarizing Agents; D011506:Proteins; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; C582790:WDR35 protein, rat; C012301:domoic acid; D007608:Kainic Acid