title: Adenosine kinase as a target for therapeutic antisense strategies in epilepsy.
abstract: OBJECTIVE
  Given the high incidence of refractory epilepsy, novel therapeutic approaches and concepts are urgently needed. To date, viral-mediated delivery and endogenous expression of antisense sequences as a strategy to prevent seizures have received little attention in epilepsy therapy development efforts. Here we validate adenosine kinase (ADK), the astrocyte-based key negative regulator of the brain's endogenous anticonvulsant adenosine, as a potential therapeutic target for antisense-mediated seizure suppression.
  
  
  METHODS
  We developed adenoassociated virus 8 (AAV8)-based gene therapy vectors to selectively modulate ADK expression in astrocytes. Cell type selectivity was achieved by expressing an Adk-cDNA in sense or antisense orientation under the control of an astrocyte-specific gfaABC1D promoter. Viral vectors where injected into the CA3 of wild-type mice or spontaneously epileptic Adk-tg transgenic mice that overexpress ADK in brain. After virus injection, ADK expression was assessed histologically and biochemically. In addition, intracranial electroencephalography (EEG) recordings were obtained.
  
  
  RESULTS
  We demonstrate in wild-type mice that viral overexpression of ADK within astrocytes is sufficient to trigger spontaneous recurrent seizures in the absence of any other epileptogenic event, whereas ADK downregulation via AAV8-mediated RNA interference almost completely abolished spontaneous recurrent seizures in Adk-tg mice.
  
  
  CONCLUSIONS
  Our data demonstrate that modulation of astrocytic ADK expression can trigger or prevent seizures, respectively. This is the first study to use an antisense approach to validate ADK as a rational therapeutic target for the treatment of epilepsy and suggests that gene therapies based on the knock down of ADK might be a feasible approach to control seizures in refractory epilepsy.
authors.affiliation: RS Dow Neurobiology Laboratories, Legacy Research, Portland, Oregon 97232, USA.
authors.forename: Panos
authors.initials: P
authors.lastname: Theofilas
authors.forename: Sukhmani
authors.initials: S
authors.lastname: Brar
authors.forename: Kerry-Ann
authors.initials: KA
authors.lastname: Stewart
authors.forename: Hai-Ying
authors.initials: HY
authors.lastname: Shen
authors.forename: Ursula S
authors.initials: US
authors.lastname: Sandau
authors.forename: David
authors.initials: D
authors.lastname: Poulsen
authors.forename: Detlev
authors.initials: D
authors.lastname: Boison
mesh_terms: D000248:Adenosine Kinase / Q000235:genetics*; D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D001253:Astrocytes / Q000502:physiology; D016373:DNA, Antisense / Q000235:genetics / Q000494:pharmacology*; D018076:DNA, Complementary / Q000235:genetics; D004569:Electroencephalography; D004827:Epilepsy / Q000235:genetics* / Q000628:therapy*; D055785:Gene Knockdown Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D005904:Glial Fibrillary Acidic Protein / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic / Q000235:genetics; D012815:Signal Processing, Computer-Assisted
chemical_list: D000927:Anticonvulsants; D016373:DNA, Antisense; D018076:DNA, Complementary; D005904:Glial Fibrillary Acidic Protein; D000248:Adenosine Kinase