title: Carbamazepine attenuates inducible nitric oxide synthase expression through Akt inhibition in activated microglial cells.
abstract: Abstract Background: Carbamazepine, which was developed primarily for the treatment of epilepsy, is now also useful for the treatment of non-epileptic disorders and inflammatory hyperalgesia. However, the mechanism of its anti-neuroinflammatory action remains poorly understood.
  
  
  OBJECTIVE
  This study elucidates the anti-neuroinflammatory capacity of carbamazepine on microglial activation and the relative mechanisms involved.
  
  
  METHODS
  The microglial BV-2 cells were pretreated with carbamazepine for 15 min before activation by lipopolysaccharide (LPS). After LPS stimulation, the expression of inducible nitric oxide synthase (iNOS) was analyzed by Western blotting (WB) and reverse transcription-polymerase chain reaction. Signaling proteins and cyclooxygenase (COX)-2 were also evaluated by WB. The levels of nitrate and tumor necrosis factor (TNF)-α were analyzed by the Griess method and enzyme-linked immunosorbant assay, respectively. The formation of intracellular reactive oxygen species (ROS) was examined by fluorescent analysis.
  
  
  RESULTS
  Carbamazepine strongly attenuated LPS-induced production of NO and iNOS protein at concentrations of 5, 10, and 20 μM. Consistently, it could markedly suppress iNOS mRNA expression stimulated by LPS. Among the signaling pathways, LPS-mediated IκBα degradation or JNK MAPK phosphorylation was not affected by carbamazepine. Interestingly, it was found that carbamazepine could concentration-dependently inhibit LPS-activated phospho-Akt expression. Nevertheless, LPS-induced ROS production was not affected by carbamazepine. Carbamazepine (20 μM) affected either COX-2 expression or TNF-α production induced by LPS with approximately 70% and 51% inhibition, respectively.
  
  
  CONCLUSIONS
  Our findings showed that carbamazepine exerted selective inhibition on LPS-induced microglial iNOS expression through the down-regulation of Akt activation, and thus may play a pivotal role of anti-neuroinflammation in its therapeutic efficacy.
authors.affiliation: Medical Intensive Care Unit, Cathay General Hospital , Taipei , Taiwan .
authors.forename: Chen-Hsu
authors.initials: CH
authors.lastname: Wang
authors.forename: Che-Jen
authors.initials: CJ
authors.lastname: Hsiao
authors.forename: Yi-Nung
authors.initials: YN
authors.lastname: Lin
authors.forename: Joe-Wei
authors.initials: JW
authors.lastname: Wu
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Kuo
authors.forename: Ching-Kuo
authors.initials: CK
authors.lastname: Lee
authors.forename: George
authors.initials: G
authors.lastname: Hsiao
mesh_terms: D000818:Animals; D002220:Carbamazepine / Q000494:pharmacology*; D002460:Cell Line; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic; D051379:Mice; D017628:Microglia / Q000187:drug effects* / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D002220:Carbamazepine; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D051057:Proto-Oncogene Proteins c-akt
keywords: LPS; iNOS; microglia