title: Fundamental Ca2+ signaling mechanisms in mouse dendritic cells: CRAC is the major Ca2+ entry pathway.
abstract: Although Ca(2+)-signaling processes are thought to underlie many dendritic cell (DC) functions, the Ca(2+) entry pathways are unknown. Therefore, we investigated Ca(2+)-signaling in mouse myeloid DC using Ca(2+) imaging and electrophysiological techniques. Neither Ca(2+) currents nor changes in intracellular Ca(2+) were detected following membrane depolarization, ruling out the presence of functional voltage-dependent Ca(2+) channels. ATP, a purinergic receptor ligand, and 1-4 dihydropyridines, previously suggested to activate a plasma membrane Ca(2+) channel in human myeloid DC, both elicited Ca(2+) rises in murine DC. However, in this study these responses were found to be due to mobilization from intracellular stores rather than by Ca(2+) entry. In contrast, Ca(2+) influx was activated by depletion of intracellular Ca(2+) stores with thapsigargin, or inositol trisphosphate. This Ca(2+) influx was enhanced by membrane hyperpolarization, inhibited by SKF 96365, and exhibited a cation permeability similar to the Ca(2+) release-activated Ca(2+) channel (CRAC) found in T lymphocytes. Furthermore, ATP, a putative DC chemotactic and maturation factor, induced a delayed Ca(2+) entry with a voltage dependence similar to CRAC. Moreover, the level of phenotypic DC maturation was correlated with the extracellular Ca(2+) concentration and enhanced by thapsigargin treatment. These results suggest that CRAC is a major pathway for Ca(2+) entry in mouse myeloid DC and support the proposal that CRAC participates in DC maturation and migration.
authors.affiliation: Howard Hughes Medical Institute, Children's Hospital, Harvard Medical School, Boston, MA 02215, USA.
authors.lastname: Hsu Sf
authors.forename: P J
authors.initials: PJ
authors.lastname: O'Connell
authors.forename: V A
authors.initials: VA
authors.lastname: Klyachko
authors.forename: M N
authors.initials: MN
authors.lastname: Badminton
authors.forename: A W
authors.initials: AW
authors.lastname: Thomson
authors.forename: M B
authors.initials: MB
authors.lastname: Jackson
authors.forename: D E
authors.initials: DE
authors.lastname: Clapham
authors.forename: G P
authors.initials: GP
authors.lastname: Ahern
mesh_terms: D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000378:metabolism* / Q000502:physiology; D020013:Calcium Signaling / Q000187:drug effects / Q000276:immunology*; D002454:Cell Differentiation / Q000276:immunology; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D004095:Dihydropyridines / Q000494:pharmacology; D016130:Immunophenotyping; D015640:Ion Channel Gating / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018408:Patch-Clamp Techniques; D019284:Thapsigargin / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D004095:Dihydropyridines; D019284:Thapsigargin; C038806:1,4-dihydropyridine; D000255:Adenosine Triphosphate