title: Pituitary adenylate cyclase-activating polypeptide is regulated by alternative splicing of transcriptional repressor REST/NRSF in nerve injury.
abstract: OBJECTIVE
  The pathophysiological mechanism for neuropathic pain (NP), one of the most common types of intractable pain, remains largely unknown. We previously reported that pituitary adenylate-cyclase activating polypeptide (PACAP) is required for the development of spinal sensitization and induction of NP. Previous in vitro studies suggest that PACAP transcription unit has two RE1-like elements and that the transcriptional repressor REST controls expression of PACAP gene. However the regulation of PACAP gene through its RE1 sites in vivo has not been studied. We have analyzed the functional role of PACAP gene RE1 element following nerve injury.
  
  
  METHODS
  An L5-spinal nerve transection (L5-SNT) in mice was used as a model of spinal injury. DRGs after the L5-SNT were studied.
  
  
  RESULTS
  PACAP mRNA increased in the DRG following spinal nerve injury. REST4, an alternatively spliced isoform of REST was shown to be regulated by the splicing activator (nSR100) and nSR100 itself also increased. Overexpression of either REST4 or nSR100 in vitro increased PACAP expression, while overexpression of REST repressed PACAP mRNA production. Reporter gene analysis showed that a novel RE1 previously predicted by in silico analysis was indeed functional. ChIP analysis showed that REST bound significantly to this RE1 in the DRG of naïve mice, while REST binding to this RE1 was decreased following spinal nerve injury. The expression of REST was decreased by nSR100-dependent alternative splicing of the REST gene, leading to derepression of PACAP.
  
  
  CONCLUSIONS
  PACAP expression in the DRG following spinal nerve injury is controlled through a novel RE1 by REST.
authors.affiliation: Department of Medical Chemistry, Kansai Medical University, Osaka, Japan; Department of Psychosomatic Medicine, Kansai Medical University, Osaka, Japan.
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Shudo
authors.affiliation: Department of Medical Chemistry, Kansai Medical University, Osaka, Japan. Electronic address: ane088@poh.osaka-med.ac.jp.
authors.forename: Masahito
authors.initials: M
authors.lastname: Shimojo
authors.affiliation: Department of Psychosomatic Medicine, Kansai Medical University, Osaka, Japan.
authors.forename: Mikihiko
authors.initials: M
authors.lastname: Fukunaga
authors.affiliation: Department of Medical Chemistry, Kansai Medical University, Osaka, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Ito
mesh_terms: D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D006367:HeLa Cells; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D016716:PC12 Cells; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000502:physiology*; D051381:Rats; D012097:Repressor Proteins / Q000096:biosynthesis* / Q000235:genetics*; D013127:Spinal Nerves / Q000293:injuries* / Q000378:metabolism*; D000099229:RE1-Silencing Transcription Factor
chemical_list: D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012097:Repressor Proteins; D000099229:RE1-Silencing Transcription Factor; C495402:Adcyap1 protein, mouse
keywords: Dorsal root ganglion; Gene transcription; Nerve injury; Neuropathic pain; PACAP; REST/NRSF