title: SGK3 regulates Ca(2+) entry and migration of dendritic cells.
abstract: OBJECTIVE
  Dendritic cells (DCs) are antigen-presenting cells linking innate and adaptive immunity. DC maturation and migration are governed by alterations of cytosolic Ca(2+) concentrations ([Ca(2+)](i)). Ca(2+) entry is in part accomplished by store-operated Ca(2+) (SOC) channels consisting of the membrane pore-forming subunit Orai and the ER Ca(2+) sensing subunit STIM. Moreover, DC functions are under powerful regulation of the phosphatidylinositol-3-kinase (PI3K) pathway, which suppresses proinflammatory cytokine production but supports DC migration. Downstream targets of PI3K include serum- and glucocorticoid-inducible kinase isoform SGK3. The present study explored, whether SGK3 participates in the regulation of [Ca(2+)](i) and Ca(2+)-dependent functions of DCs, such as maturation and migration.
  
  
  RESULTS
  Experiments were performed with bone marrow derived DCs from gene targeted mice lacking SGK3 (sgk3(-/-)) and DCs from their wild type littermates (sgk3(+/+)). Maturation, phagocytosis and cytokine production were similar in sgk3(-/-) and sgk3(+/+) DCs. However, SOC entry triggered by intracellular Ca(2+) store depletion with the endosomal Ca(2+) ATPase inhibitor thapsigargin (1 µM) was significantly reduced in sgk3(-/-) compared to sgk3(+/+) DCs. Similarly, bacterial lipopolysaccharide (LPS, 1 µg/ml)- and chemokine CXCL12 (300 ng/ml)- induced increase in [Ca(2+)](i) was impaired in sgk3(-/-) DCs. Moreover, currents through SOC channels were reduced in sgk3(-/-) DCs. STIM2 transcript levels and protein abundance were significantly lower in sgk3(-/-) DCs than in sgk3(+/+) DCs, whereas Orai1, Orai2, STIM1 and TRPC1 transcript levels and/or protein abundance were similar in sgk3-/- and sgk3(+/+) DCs. Migration of both, immature DCs towards CXCL12 and LPS-matured DCs towards CCL21 was reduced in sgk3(-/-) as compared to sgk3(+/+) DCs. Migration of sgk3(+/+) DCs was further sensitive to SOC channel inhibitor 2-APB (50 µM) and to STIM1/STIM2 knock-down.
  
  
  CONCLUSIONS
  SGK3 contributes to the regulation of store-operated Ca(2+) entry into and migration of dendritic cells, effects at least partially mediated through SGK3-dependent upregulation of STIM2 expression.
authors.affiliation: Department of Physiology, University of Tübingen, Tübingen, Germany.
authors.forename: Evi
authors.initials: E
authors.lastname: Schmid
authors.forename: Madhuri
authors.initials: M
authors.lastname: Bhandaru
authors.forename: Meerim K
authors.initials: MK
authors.lastname: Nurbaeva
authors.forename: Wenting
authors.initials: W
authors.lastname: Yang
authors.forename: Kalina
authors.initials: K
authors.lastname: Szteyn
authors.forename: Antonella
authors.initials: A
authors.lastname: Russo
authors.forename: Christina
authors.initials: C
authors.lastname: Leibrock
authors.forename: Leonid
authors.initials: L
authors.lastname: Tyan
authors.forename: David
authors.initials: D
authors.lastname: Pearce
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Shumilina
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D000818:Animals; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism; D020013:Calcium Signaling; D002465:Cell Movement; D002478:Cells, Cultured; D016207:Cytokines / Q000502:physiology; D003713:Dendritic Cells / Q000201:enzymology* / Q000502:physiology; D005260:Female; D015870:Gene Expression; D008297:Male; D008564:Membrane Potentials; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018408:Patch-Clamp Techniques; D010587:Phagocytosis; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D000099184:Serum-Glucocorticoid Regulated Kinases
chemical_list: D015220:Calcium Channels; D016207:Cytokines; D017346:Protein Serine-Threonine Kinases; C523602:Sgk3 protein, mouse; D000099184:Serum-Glucocorticoid Regulated Kinases