title: Orai1 and CRAC channel dependence of VEGF-activated Ca2+ entry and endothelial tube formation.
abstract: BACKGROUND
  Orai1 and the associated calcium release-activated calcium (CRAC) channel were discovered in the immune system. Existence also in endothelial cells has been suggested, but the relevance to endothelial biology is mostly unknown.
  
  
  OBJECTIVE
  The aim of this study was to investigate the relevance of Orai1 and CRAC channels to vascular endothelial growth factor (VEGF) and endothelial tube formation.
  
  
  RESULTS
  In human umbilical vein endothelial cells, Orai1 disruption by short-interfering RNA or dominant-negative mutant Orai1 inhibited calcium release-activated (store-operated) calcium entry, VEGF-evoked calcium entry, cell migration, and in vitro tube formation. Expression of exogenous wild-type Orai1 rescued the tube formation. VEGF receptor-2 and Orai1 partially colocalized. Orai1 disruption also inhibited calcium entry and tube formation in endothelial progenitor cells from human blood. A known blocker of the immune cell CRAC channel (3-fluoropyridine-4-carboxylic acid (2',5'-dimethoxybiphenyl-4-yl)amide) was a strong blocker of store-operated calcium entry in endothelial cells and inhibited calcium entry evoked by VEGF in 3 types of human endothelial cell. The compound lacked effect on VEGF-evoked calcium-release, STIM1 clustering, and 2 types of transient receptor potential channels, TRPC6 and TRPV4. Without effect on cell viability, the compound inhibited human endothelial cell migration and tube formation in vitro and suppressed angiogenesis in vivo in the chick chorioallantoic membrane. The compound showed 100-fold greater potency for endothelial compared with immune cell calcium entry.
  
  
  CONCLUSIONS
  The data suggest positive roles for Orai1 and CRAC channels in VEGF-evoked calcium entry and new opportunity for chemical modulation of angiogenesis.
authors: Institute of Membrane & Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom.
authors: Jing
authors: J
authors: Li
authors: Richard M
authors: RM
authors: Cubbon
authors: Lesley A
authors: LA
authors: Wilson
authors: Mohamed S
authors: MS
authors: Amer
authors: Lynn
authors: L
authors: McKeown
authors: Bing
authors: B
authors: Hou
authors: Yasser
authors: Y
authors: Majeed
authors: Sarka
authors: S
authors: Tumova
authors: Victoria A L
authors: VA
authors: Seymour
authors: Hilary
authors: H
authors: Taylor
authors: Martin
authors: M
authors: Stacey
authors: David
authors: D
authors: O'Regan
authors: Richard
authors: R
authors: Foster
authors: Karen E
authors: KE
authors: Porter
authors: Mark T
authors: MT
authors: Kearney
authors: David J
authors: DJ
authors: Beech
mesh_terms: D000818:Animals; D016466:CHO Cells; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D002642:Chick Embryo; D006224:Cricetinae; D003412:Cricetulus; D004730:Endothelium, Vascular / Q000166:cytology / Q000196:embryology / Q000254:growth & development*; D057809:HEK293 Cells; D006801:Humans; D000071740:ORAI1 Protein; D042442:Vascular Endothelial Growth Factors / Q000502:physiology*
chemical_list: D015220:Calcium Channels; D000071740:ORAI1 Protein; C510746:ORAI1 protein, human; D042442:Vascular Endothelial Growth Factors; D002118:Calcium