title: Application of an ex vivo cellular model of circadian variation for bipolar disorder research: a proof of concept study.
abstract: OBJECTIVE
  Disruption of circadian function has been observed in several human disorders, including bipolar disorder (BD). Research into these disorders can be facilitated by human cellular models that evaluate external factors (zeitgebers) that impact circadian pacemaker activity. Incorporating a firefly luciferase reporter system into human fibroblasts provides a facile, bioluminescent readout that estimates circadian phase, while leaving the cells intact. We evaluated whether this system can be adapted to clinical BD research and whether it can incorporate zeitgeber challenge paradigms.
  
  
  METHODS
  Fibroblasts from patients with bipolar I disorder (BD-I) (n = 13) and controls (n = 12) were infected ex vivo with a lentiviral reporter incorporating the promoter sequences for Bmal1, a circadian gene to drive expression of the firefly luciferase gene. Following synchronization, the bioluminescence was used to estimate period length. Phase response curves (PRCs) were also generated following forskolin challenge and the phase response patterns were characterized.
  
  
  RESULTS
  Period length and PRCs could be estimated reliably from the constructs. There were no significant case-control differences in period length, with a nonsignificant trend for differences in PRCs following the phase-setting experiments.
  
  
  CONCLUSIONS
  An ex vivo cellular fibroblast-based model can be used to investigate circadian function in BD-I. It can be generated from specific individuals and this could usefully complement ongoing circadian clinical research.
authors.affiliation: Department of Psychiatry, Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
authors.forename: Mikhil N
authors.initials: MN
authors.lastname: Bamne
authors.forename: Christine A
authors.initials: CA
authors.lastname: Ponder
authors.forename: Joel A
authors.initials: JA
authors.lastname: Wood
authors.forename: Hader
authors.initials: H
authors.lastname: Mansour
authors.forename: Ellen
authors.initials: E
authors.lastname: Frank
authors.forename: David J
authors.initials: DJ
authors.lastname: Kupfer
authors.forename: Michael W
authors.initials: MW
authors.lastname: Young
authors.forename: Vishwajit L
authors.initials: VL
authors.lastname: Nimgaonkar
mesh_terms: D056930:ARNTL Transcription Factors / Q000235:genetics / Q000378:metabolism; D000328:Adult; D000932:Antiemetics / Q000494:pharmacology; D001714:Bipolar Disorder / Q000473:pathology* / Q000503:physiopathology*; D002460:Cell Line; D003907:Dexamethasone / Q000494:pharmacology; D005260:Female; D005347:Fibroblasts / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D014162:Transfection; D055815:Young Adult
chemical_list: D056930:ARNTL Transcription Factors; C538960:BMAL1 protein, human; D000932:Antiemetics; D003907:Dexamethasone
keywords: BmalI; biorhythm; bipolar disorder; circadian; fibroblast