Requirement for Ca2+ signaling in the mechanism of thrombin-induced increase in endothelial permeability.
We compared the thrombin-activated responses in human umbilical vein endothelial cells (HUVECs) and a HUVEC-derived cell line, ECV304. Thrombin induced a 40-50% decrease in transendothelial monolayer electrical resistance and a twofold increase in 125I-albumin permeability in HUVECs, whereas it failed to alter the endothelial barrier function in ECV304 cells. Thrombin produced a brisk intracellular Ca2+ concentration transient and phosphorylation of 20-kDa myosin light chain in HUVECs but not in ECV304 cells. Thrombin-induced phosphoinositide hydrolysis was comparable in ECV304 cells and HUVECs, indicating the activation of thrombin receptors in both cell types. La3+ reduced both the thrombin-induced decrease in endothelial monolayer electrical resistance and the increase in 125I-albumin permeability in HUVECs. Because the absence of Ca2+ signaling could explain the impairment in the permeability response in ECV304 cells, we studied the effect of increasing intracellular Ca2+ concentration in ECV304 cells with thapsigargin. Exposure of ECV304 cells to thapsigargin caused decreased endothelial monolayer electrical resistance and increased 125I-albumin permeability. These results indicate that Ca2+ influx and activation of Ca2+-dependent signaling pathways are important determinants of the thrombin-induced increase in endothelial permeability.
Sandoval
R
R
Department of Pharmacology, College of Medicine, The University of Illinois at Chicago, Chicago, Illinois 60612, USA.
Malik
A B
AB
Naqvi
T
T
Mehta
D
D
Tiruppathi
C
C
D015703:Antigens, CD; D015820:Cadherins / Q000096:biosynthesis; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002199:Capillary Permeability / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D017097:Electric Impedance; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D007424:Intracellular Fluid / Q000378:metabolism; D007811:Lanthanum / Q000494:pharmacology; D018994:Myosin Light Chains / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D018179:Receptors, Thrombin / Q000378:metabolism; D012711:Serum Albumin, Radio-Iodinated / Q000378:metabolism; D019284:Thapsigargin / Q000494:pharmacology; D013917:Thrombin / Q000378:metabolism* / Q000494:pharmacology; D000099152:Cadherin 5
D015703:Antigens, CD; D015820:Cadherins; D002118:Calcium; D015544:Inositol 1,4,5-Trisphosphate; D007811:Lanthanum; D018994:Myosin Light Chains; D010716:Phosphatidylinositols; D018179:Receptors, Thrombin; D012711:Serum Albumin, Radio-Iodinated; D019284:Thapsigargin; D013917:Thrombin; D000099152:Cadherin 5; C028521:lanthanum chloride