Lipopolysaccharide-mediated cell activation without rapid mobilization of cytosolic free calcium.
The involvement of cytosolic free calcium (Ca2+) as a second messenger in lipopolysaccharide (LPS)-activated cellular pathways remains controversial. Using human monocyte-like THP-1 cells stably transfected with glycosylphosphatidylinositol-anchored human CD14, we have monitored the concentration of intracellular Ca2+ after sequential addition of LPS, ATP, and ionomycin. Whereas ATP and ionomycin induced rapid elevations of cytosolic Ca2+, no such changes were observed after LPS addition. These data argue against the participation of cytosolic Ca2+ in the CD14-dependent LPS activation pathway.
Bosshart
Herbert
H
Department of Surgery, Zurich University Hospital, Sternwartstrasse 14, CH-8091 Zurich, Switzerland. herbert.bosshart@usz.ch
Heinzelmann
Michael
M
D000255:Adenosine Triphosphate / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism*; D018014:Gene Transfer Techniques; D006801:Humans; D015759:Ionomycin / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D018950:Lipopolysaccharide Receptors / Q000235:genetics / Q000276:immunology*; D008070:Lipopolysaccharides / Q000378:metabolism*; D009000:Monocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*
D007476:Ionophores; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D015759:Ionomycin; D000255:Adenosine Triphosphate; D002118:Calcium