title: Effect of oxidative stress on TRPM2 and TRPC3 channels in B lymphoblast cells in bipolar disorder.
abstract: OBJECTIVE
  Recent findings implicate the calcium-permeable nonselective ion channels transient receptor potential (TRP) melastatin subtype 2 (TRPM2) and canonical subtype 3 (TRPC3) in the pathogenesis of bipolar disorder (BD). These channels are involved in calcium and oxidative stress signaling, both of which are disrupted in BD. Thus, we sought to determine if these channels are differentially affected by oxidative stress in cell lines of BD patient origin.
  
  
  METHODS
  B lymphoblast cell lines (BLCLs) from bipolar I disorder (BD-I) patients (n = 6) and healthy controls (n = 5) were challenged with the oxidative stressor rotenone (2.5 μM and 10 μM) or vehicle for acute (24 hours) and chronic (four days) intervals. Cell viability was measured using propidium iodide, while TRPM2- and TRPC3-mediated calcium fluxes were measured in the presence of their respective activators (H(2) O(2) and 1-oleoyl-2-acetyl-sn-glycerol) using Fluo-4. Changes in TRPM2 and TRPC3 expression levels were determined by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and Western blotting.
  
  
  RESULTS
  Cell viability decreased with increasing dose and duration of rotenone treatment, with BD-I patient BLCLs more susceptible than controls acutely (p < 0.001). A dose-dependent decrease in TRPC3 protein expression occurred after chronic (24%, p = 0.008) but not acute rotenone treatment. Interestingly, H(2) O(2) -provoked TRPM2-dependent calcium fluxes revealed an interaction between the effects of stressor addition and diagnostic subject group (p = 0.003).
  
  
  CONCLUSIONS
  These data support an important role for TRPM2 and TRPC3 in sensing and responding to oxidative stress and in transducing oxidative stress signaling to intracellular calcium homeostasis and cellular stress responses, all of which have been implicated in the pathophysiology of BD.
authors.affiliation: Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada.
authors.forename: Angela S
authors.initials: AS
authors.lastname: Roedding
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Gao
authors.forename: Wynne
authors.initials: W
authors.lastname: Au-Yeung
authors.forename: Tiffany
authors.initials: T
authors.lastname: Scarcelli
authors.forename: Peter P
authors.initials: PP
authors.lastname: Li
authors.forename: Jerry J
authors.initials: JJ
authors.lastname: Warsh
mesh_terms: D000328:Adult; D001402:B-Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D001714:Bipolar Disorder / Q000276:immunology / Q000473:pathology*; D002118:Calcium / Q000378:metabolism; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007306:Insecticides / Q000494:pharmacology; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012402:Rotenone / Q000494:pharmacology; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*; D050053:TRPM Cation Channels / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D055815:Young Adult
chemical_list: D007306:Insecticides; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D050052:TRPC Cation Channels; C104603:TRPC3 cation channel; D050053:TRPM Cation Channels; C121934:TRPM2 protein, human; D012402:Rotenone; D051547:Heme Oxygenase-1; D002118:Calcium