[en] To measure intracellular free Ca2+ concentration ([Ca2+]i) and superoxide (O2) production in human alveolar macrophages, we used the fluorescent Ca2+ indicator fura-2 and the O2-sensitive dye dihydrorhodamine-123, which becomes fluorescent in its oxidized form, rhodamine-123. We describe a new double-dye technique whereby the kinetics of both [Ca2+]i levels and O2. production can be monitored simultaneously. This technique was developed in the dimethylsulfoxide-differentiated monocytic-like U-937 cell line (not equal to U-937), validated by comparison with single dye measurements and applied to human alveolar macrophages. The chemotactic peptide N-formyl-L-Methionyl-L-Leucyl-L-Phenylalanine induced in both cell types a similar transient elevation in [Ca2+]i, followed within seconds by a sustained increase in O2 production, which was however 4-fold weaker in not equal to U-937 cells. These results indicate that O2 production is an early event following the stimulation of human alveolar macrophages. This new double-dye technique may be relevant to other O2 ion-producing cells and could help to define more precisely the kinetics of the events leading to this biological response.
Disciplines :
Biochemistry, biophysics & molecular biology
Identifiers :
UNILU:UL-ARTICLE-2008-214
Author, co-author :
Bueb, Jean-Luc ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Life Science Research Unit
Gallois, A.
Schneider, J. C.
Parini, J. P.
Tschirhart, Eric ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Life Science Research Unit
Language :
English
Title :
A double-labelling fluorescent assay for concomitant measurements of [Ca2+]i and O2. production in human macrophages