title: CRAC channels are required for [Ca(2+)]i oscillations and c-fos gene expression after muscarinic acetylcholine receptor activation in leukemic T cells.
abstract: OBJECTIVE
  T lymphocytes express muscarinic acetylcholine receptors (mAChRs) involved in regulating their proliferation, differentiation and cytokine release. Activation of M1, M3 or M5 mAChRs increases the intracellular Ca(2+) concentration ([Ca(2+)]i) through inositol-1,4,5-phosphate (IP3)-mediated Ca(2+) release from endoplasmic reticulum Ca(2+) stores. In addition, T lymphocytes express Ca(2+)-release activated Ca(2+) (CRAC) channels to induce Ca(2+) influx and to regulate diverse immune functions. Our aim in the present study was to assess the role of CRAC channels during mAChR activation in the Ca(2+)-dependent transduction that contributes to the regulation of T cell function.
  
  
  METHODS
  Changes in [Ca(2+)]i following mAChR activation on human leukemic T cells, CCRF-CEM (CEM), were monitored using fura-2, based on the ratio of 510nm fluorescences elicited by excitation at 340nm and 380nm (R340/380).
  
  
  RESULTS
  We demonstrate that CEM cells express mainly M3 and M5 mAChRs, but little the M1 subtype, and that oxotremorine-M (Oxo-M), an mAChR agonist, induces an initial transient increase in [Ca(2+)]i followed by repetitive [Ca(2+)]i oscillations. Removing extracellular Ca(2+) or pharmacological blockade of CRAC channels abolished the [Ca(2+)]i oscillations without affecting the initial [Ca(2+)]i transient induced by Oxo-M. Moreover, CRAC channel blockade also suppressed Oxo-M-induced c-fos and interleukin-2 expression.
  
  
  CONCLUSIONS
  These results suggest that upon M3 or M5 mAChR activation, IP3-mediated Ca(2+) release induces extracellular Ca(2+) influx through CRAC channels, which generates repetitive [Ca(2+)]i oscillations and, in turn, enhances c-fos gene expression in T lymphocytes.
authors.affiliation: Department of Pharmacology, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts, Kyotanabe, Kyoto 610-0395, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Mashimo
authors.affiliation: Department of Pharmacology, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts, Kyotanabe, Kyoto 610-0395, Japan.
authors.forename: Yukako
authors.initials: Y
authors.lastname: Yurie
authors.affiliation: Department of Molecular Pharmacology, Kitasato University School of Pharmaceutical Sciences, Minato-ku, Tokyo 108-8641, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Kawashima
authors.affiliation: Department of Pharmacology, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts, Kyotanabe, Kyoto 610-0395, Japan. Electronic address: tfujii@dwc.doshisha.ac.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fujii
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000071739:Calcium Release Activated Calcium Channels / Q000502:physiology*; D045744:Cell Line, Tumor; D016762:Genes, fos; D006801:Humans; D015458:Leukemia, T-Cell / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D011976:Receptors, Muscarinic / Q000378:metabolism*
chemical_list: D000071739:Calcium Release Activated Calcium Channels; D011976:Receptors, Muscarinic; D002118:Calcium
keywords: Acetylcholine; Ca(2+) release-activated Ca(2+) channels; Muscarinic acetylcholine receptor; T lymphocytes; [Ca(2+)](i) oscillation