Cellular Physiology and Biochemistry (Jan 2014)

Akt2- and ETS1-Dependent IP3 Receptor 2 Expression in Dendritic Cell Migration

  • Wenting Yang,
  • Meerim K. Nurbaeva,
  • Evi Schmid,
  • Antonella Russo,
  • Ahmad Almilaji,
  • Kalina Szteyn,
  • Jing Yan,
  • Caterina Faggio,
  • Ekaterina Shumilina,
  • Florian Lang

DOI
https://doi.org/10.1159/000356664
Journal volume & issue
Vol. 33, no. 1
pp. 222 – 236

Abstract

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Background/Aims: The protein kinase Akt2/PKBβ is a known regulator of macrophage and dendritic cell (DC) migration. The mechanisms linking Akt2 activity to migration remained, however, elusive. DC migration is governed by Ca2+ signaling. We thus explored whether Akt2 regulates DC Ca2+ signaling. Methods: DCs were derived from bone marrow of Akt2-deficient mice (akt2-/-) and their wild type littermates (akt2+/+). DC maturation was induced by lipopolysaccharides (LPS) and evaluated by flow cytometry. Cytosolic Ca2+ concentration was determined by Fura-2 fluorescence, channel activity by whole cell recording, transcript levels by RT-PCR, migration utilizing transwells. Results: Upon maturation, chemokine CCL21 stimulated migration of akt2+/+ but not akt2-/- DCs. CCL21-induced increase in cytosolic Ca2+ concentration, thapsigargin-induced release of Ca2+ from intracellular stores with subsequent store-operated Ca2+ entry (SOCE), ATP-induced inositol 1,4,5-trisphosphate (IP3)-dependent Ca2+ release as well as Ca2+ release-activated Ca2+ (CRAC) channel activity were all significantly lower in mature akt2-/- than in mature akt2+/+ DCs. Transcript levels of IP3 receptor IP3R2 and of IP3R2 regulating transcription factor ETS1 were significantly higher in akt2+/+ than in akt2-/- DCs prior to maturation and were upregulated by LPS stimulation (1h) in akt2+/+ and to a lower extent in akt2-/- DCs. Following maturation, protein abundance of IP3R2 and ETS1 were similarly higher in akt2+/+ than in akt2-/- DCs. The IP3R inhibitor Xestospongin C significantly decreased CCL21-induced migration of akt2+/+DCs and abrogated the differences between genotypes. Finally, knock-down of ETS1 with siRNA decreased IP3R2 mRNA abundance, thapsigargin- and ATP-induced Ca2+ release, SOCE and CRAC channel activation, as well as DC migration. Conclusion: Akt2 upregulates DC migration at least in part by ETS1-dependent stimulation of IP3R2 transcription.

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