Inhibitory effects of N-acetylcysteine on the functional responses of human eosinophils in vitro.
BACKGROUND
Oxidative stress appears to be relevant in the pathogenesis of inflammation in allergic diseases like bronchial asthma. Eosinophils are oxidant-sensitive cells considered as key effectors in allergic inflammation.


OBJECTIVE
The aim of this work was to study the effects of the clinically used antioxidant N-acetyl-L-cysteine (NAC) on the functional responses of human-isolated eosinophils.


METHODS
Human eosinophils were purified from the blood of healthy donors by a magnetic bead separation system. The effects of NAC were investigated on the generation of reactive oxygen species (chemiluminescence and flow cytometry), Ca(2+) signal (fluorimetry), intracellular glutathione (GSH; flow cytometry), p47(phox)-p67(phox) translocation (Western blot) and eosinophil cationic protein (ECP) release (radioimmunoassay).


RESULTS
NAC (0.1-1 mm) inhibited the extracellular generation of oxygen species induced by N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) and eotaxin (in the presence of IL-5) with -logIC(50) values of 3.61+/-0.03 and 3.36+/-0.09, respectively. Also, the intracellular generation of hydrogen peroxide was virtually abolished by NAC (0.5-1 mm). NAC (1 mm) did not alter the fMLP-induced Ca(2+) signal but augmented the eosinophil content of reduced GSH and inhibited p47(phox)-p67(phox) translocation. NAC inhibited the release of ECP ( approximately 90% inhibition at 1 mm) from fMLP-activated eosinophils.


CONCLUSIONS
Inhibition by NAC of human eosinophil functions in vitro is potentially useful in the treatment of allergic inflammation.
Martinez-Losa
M
M
Department of Pharmacology, University of Valencia, Valencia, Spain.
Cortijo
J
J
Juan
G
G
O'Connor
J E
JE
Sanz
M J
MJ
Santangelo
F
F
Morcillo
E J
EJ
D000111:Acetylcysteine / Q000494:pharmacology*; D002118:Calcium / Q000097:blood; D016923:Cell Death / Q000187:drug effects; D054413:Chemokine CCL11; D019742:Chemokines, CC / Q000037:antagonists & inhibitors / Q000494:pharmacology; D047150:Eosinophil Cationic Protein / Q000097:blood; D004804:Eosinophils / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005978:Glutathione / Q000097:blood; D006801:Humans; D049449:Luminescence; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D019255:NADPH Oxidases / Q000097:blood; D010750:Phosphoproteins / Q000097:blood; D017382:Reactive Oxygen Species / Q000378:metabolism; D014178:Translocation, Genetic / Q000187:drug effects
C515456:CCL11 protein, human; D054413:Chemokine CCL11; D019742:Chemokines, CC; D016166:Free Radical Scavengers; D010750:Phosphoproteins; D017382:Reactive Oxygen Species; C079789:neutrophil cytosol factor 67K; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D047150:Eosinophil Cationic Protein; C479220:RNASE3 protein, human; D005978:Glutathione; D002118:Calcium; D000111:Acetylcysteine