Essential role of a Ca2+-selective, store-operated current (ISOC) in endothelial cell permeability: determinants of the vascular leak site

Circ Res. 2005 Apr 29;96(8):856-63. doi: 10.1161/01.RES.0000163632.67282.1f. Epub 2005 Mar 24.

Abstract

Store-operated calcium (SOC) entry is sufficient to disrupt the extra-alveolar, but not the alveolar, endothelial cell barrier. Mechanism(s) underlying such insensitivity to transitions in cytosolic calcium ([Ca2+]i) in microvascular endothelial cells are unknown. Depletion of stored Ca2+ activates a larger SOC entry response in extra-alveolar (pulmonary artery; PAECs) than alveolar (pulmonary microvascular; PMVECs) endothelial cells. In vivo permeation studies revealed that Ca2+ store depletion activates similar nonselective cationic conductances in PAECs and PMVECs, while only PAECs possess the calcium-selective, store-operated Ca2+ entry current, I(SOC). Pretreatment with the type 4 phosphodiesterase inhibitor, rolipram, abolished thapsigargin-activated I(SOC) in PAECs, and revealed I(SOC) in PMVECs. Rolipram pretreatment shifted the thapsigargin-induced fluid leak site from extra-alveolar to alveolar vessels in the intact pulmonary circulation. Thus, our results indicate I(SOC) provides a [Ca2+]i source that is needed to disrupt the endothelial cell barrier, and demonstrate that intracellular events controlling I(SOC) activation coordinate the site-specific vascular response to inflammation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenylyl Cyclases / physiology
  • Animals
  • Calcium / metabolism*
  • Calcium Channels / physiology*
  • Capillary Permeability*
  • Cyclic AMP / metabolism
  • Endothelial Cells / metabolism*
  • Ion Channels / physiology
  • Lanthanum / pharmacology
  • Models, Molecular
  • Rats
  • Rolipram / pharmacology
  • TRPC Cation Channels
  • Thapsigargin / pharmacology

Substances

  • Calcium Channels
  • Ion Channels
  • TRPC Cation Channels
  • TRPC4 ion channel
  • Thapsigargin
  • Lanthanum
  • Cyclic AMP
  • Adenylyl Cyclases
  • Rolipram
  • Calcium