Lymphocyte adhesion-dependent calcium signaling in human endothelial cells.
Vascular endothelial cells (ECs) can undergo dramatic phenotypic and functional alterations in response to humoral and cellular stimuli. These changes promote endothelial participation in the inflammatory response through active recruitment of immune effector cells, increased vascular permeability, and alteration in vascular tone. In an attempt to define early events in lymphocyte-mediated EC signaling, we investigated cytosolic-free calcium (Ca2+) changes in single, Fluo-3-labeled human umbilical vein ECs (HUVECs), using an ACAS interactive laser cytometer. Of all lymphocyte subsets tested, allogeneic CD3-, CD56+ natural killer (NK) cells uniquely elicited oscillatory EC Ca2+ signals in cytokine (interleukin [IL]-1- or tumor necrosis factor [TNF])-treated ECs. The induction of these signals required avid intercellular adhesion, consisted of both Ca2+ mobilization and extracellular influx, and was associated with EC inositol phosphate (IP) generation. Simultaneous recording of NK and EC Ca2+ signals using two-color fluorescence detection revealed that, upon adhesion, NK cells flux prior to EC. Lymphocyte Ca2+ buffering with 1,2-bis-5-methyl-amino-phenoxylethane-N,N,N'-tetra-acetoxymethyl acetate (MAPTAM) demonstrated that lymphocyte fluxes are, in fact, prerequisites for the adhesion-dependent EC signals. mAb studies indicate that the beta 2 integrin-intercellular adhesion molecule (ICAM)-1 adhesion pathway is critically involved. However, ICAM-1 antisense oligonucleotide inhibition of IL-1-mediated ICAM-1 hyperinduction had no effect on EC Ca2+ signaling in lymphocyte-EC conjugates, indicating that additional cytokine-induced EC alteration is required. These experiments combine features of lymphocyte-endothelial interactions, intercellular adhesion, EC cytokine activation and transmembrane signaling. The results implicate the IP/Ca2+ second messenger pathway in EC outside-in signaling induced by cytotoxic lymphocytes, and suggest that these signals may play a role in EC alteration by lymphocyte adhesion.
Pfau
S
S
Division of Cardiovascular Medicine and Molecular Cardiobiology, Yale University School of Medicine, New Haven, Connecticut 06536-0812.
Leitenberg
D
D
Rinder
H
H
Smith
B R
BR
Pardi
R
R
Bender
J R
JR
D001483:Base Sequence; D018821:CD18 Antigens; D002118:Calcium / Q000378:metabolism*; D002448:Cell Adhesion / Q000502:physiology*; D002450:Cell Communication / Q000502:physiology*; D003600:Cytosol / Q000378:metabolism; D004730:Endothelium, Vascular / Q000276:immunology*; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism; D016023:Integrins / Q000502:physiology; D018799:Intercellular Adhesion Molecule-1 / Q000502:physiology; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology; D016131:Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology*; D008969:Molecular Sequence Data; D015739:Nocodazole / Q000494:pharmacology; D015398:Signal Transduction; D014471:Umbilical Veins / Q000166:cytology
D018821:CD18 Antigens; D007295:Inositol Phosphates; D016023:Integrins; D018799:Intercellular Adhesion Molecule-1; D015739:Nocodazole; D002118:Calcium