Subcellular localization of leukotriene receptors in human endothelial cells.
Leukotriene B(4) (LTB(4)), a potent chemotactic and immune-modulating mediator, signals via two receptors, BLT(1) and BLT(2). Recently, we reported that BLT(1) is the predominating BLT expressed on human umbilical vein endothelial cells (HUVEC), and that BLT(1) mediated functions are enhanced by LTB(4) and lipopolysaccharide (LPS), but not by TNFα. Here, we demonstrate that BLT(1) is found on the outer cell membrane of HUVECs but also in intracellular granules, co-localized with monocyte chemotactic protein-1 and P-selectin, but not with interleukin-8 and von Willebrand factor. Upon stimulation with LTB(4) or LPS, more BLT(1) protein is found, now evenly distributed over the cytoplasm and in the cell nucleus, but less on the cell surface. An MAP kinase inhibitor prevented this enhancement and translocation, suggesting this signaling pathway to be crucial. Thus, BLT(1), a G-protein-coupled 7-transmembrane receptor, is located in various subcellular compartments in endothelial cells, which may have implications for cellular LT dependent responses and target accessibility for BLT(1) antagonists.
Johansson
Anne-Sofie
AS
Center for Inflammation and Hematology Research, Department of Medicine, Karolinska University Hospital Huddinge, Karolinska Institutet, Stockholm, Sweden.
Haeggström
Jesper Z
JZ
Hultenby
Kjell
K
Palmblad
Jan
J
D002451:Cell Compartmentation; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000737:chemistry* / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology; D006801:Humans; D007975:Leukotriene B4 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D018077:Receptors, Leukotriene / Q000032:analysis*; D018102:Receptors, Leukotriene B4 / Q000032:analysis* / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects
C513240:LTB4R protein, human; C485878:LTB4R2 protein, human; D008070:Lipopolysaccharides; D018077:Receptors, Leukotriene; D018102:Receptors, Leukotriene B4; D007975:Leukotriene B4