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Enhanced Ca 2+ entry and Na + /Ca 2+ exchanger activity in dendritic cells from AMP‐activated protein kinase‐deficient mice
Author(s) -
Nurbaeva Meerim K.,
Schmid Evi,
Szteyn Kalina,
Yang Wenting,
Viollet Benoit,
Shumilina Ekaterina,
Lang Florian
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.12-204024
Subject(s) - ampk , chemistry , thapsigargin , protein kinase a , microbiology and biotechnology , amp activated protein kinase , extracellular , phosphorylation , biochemistry , biology
In dendritic cells (DCs), chemotactic chemokines, such as CXCL12, rapidly increase cytosolic Ca 2+ concentrations ([Ca 2+ ] i ) by triggering Ca 2+ release from intracellular stores followed by store‐operated Ca 2+ (SOC) entry. Increase of [Ca 2+ ] i is blunted and terminated by Ca 2+ extrusion, accomplished by K + independent Na + /Ca 2+ exchangers (NCXs) and K + ‐dependent Na + /Ca 2+ exchangers (NCKXs). Increased [Ca 2+ ] i activates energy‐sensing AMP‐activated protein kinase (AMPK), which suppresses proinflammatory responses of DCs and macrophages. The present study explored whether AMPK participates in the regulation of DC [Ca 2+ ] i and migration. DCs were isolated from AMPKα1‐deficient ( ampk –/– ) mice and, as control, from their wild‐type ( ampk +/+ ) littermates. AMPKα1, Orai1‐2, STIM1‐2, and mitochondrial calcium uniporter protein expression was determined by Western blotting, [Ca 2+ ] i by Fura‐2 fluorescence, SOC entry by inhibition of endosomal Ca 2+ ATPase with thapsigargin (1 μM), Na + /Ca 2+ exchanger activity from increase of [Ca 2+ ] i , and respective whole‐cell current in patch clamp following removal of extracellular Na + . Migration was quantified utilizing transwell chambers. AMPKα1 protein is expressed in ampk +/+ DCs but not in ampk –/– DCs. CXCL12 (300 ng/ml)‐induced increase of [Ca 2+ ] i , SOC entry, Orai 1 protein abundance, NCX, and NCKX were all significantly higher in ampk –/– DCs than in ampk +/+ DCs. NCX and NCKX currents were similarly increased in ampk –/– DCs. Moreover, CXCL12 (50 ng/ml)‐induced DC migration was enhanced in ampk –/– DCs. AMPK thus inhibits SOC entry, Na + /Ca 2+ exchangers, and migration of DCs.—Nurbaeva, M. K., Schmid, E., Szteyn, K., Yang, W., Viollet, B., Shumilina, E., Lang, F. Enhanced Ca 2+ entry and Na + /Ca2 + exchanger activity in dendritic cells from AMP‐activated protein kinase‐deficient mice. FASEB J. 26, 3049–3058 (2012). www.fasebj.org