Expression of calgranulin A/B heterodimer after acute inhalation of endotoxin: proteomic approach and validation.
BACKGROUND
The acute inhalation of endotoxin mimicks several aspects of the inflammation related to chronic obstructive pulmonary disease (COPD). The aim of the current study was to identify and to validate biomarkers of endotoxin-induced airways' inflammation.


METHODS
The cellular count in the induced-sputum, was measured before and after an inhalation of 20 mcg endotoxin, in 8 healthy volunteers. A proteomic analysis was applied to identify the more relevant proteins expression, before measurement by ELISA. The amplitude and the repeatability of the markers were evaluated among another population of 12 healthy subjects.


RESULTS
There was a significant rise of viable cells (p <0.01), macrophages (p <0.05), and neutrophils (p <0.02) 24 hours after endotoxin inhalation, and of neutrophils (p <0.02) and lymphocytes (p <0.05) at 6 hours. Among the highest amplitude responses, the two dimensional electrophoretic separation shown proteolytic activity and overexpression of protein spots. By MALDI-TOF mass spectrometry, the last were identified as calgranulin A and B. The expression of the bioactive A/B heterodimeric complex was confirmed by ELISA both in the sputum (p <0.01) and at the blood level (p <0.01). The intra-subject repeatability of the sputum calgranulin A/B was highly significant (p <0.0001).


CONCLUSIONS
In healthy subjects, the inhalation of endotoxin induced expression of sputum calgranulin A/B that could be a biomarker of the endotoxin response/exposure.
Clinic of Immuno-allergology, CHU Brugmann (ULB), pl Van Gehuchten 4, B-1020 Brussels, Belgium. omichel@ulb.ac.be.
Olivier
O
Michel
Virginie
V
Doyen
Baptiste
B
Leroy
Benjamin
B
Bopp
Duc Huy Phong
DH
Dinh
Francis
F
Corazza
Ruddy
R
Wattiez
D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D040501:Calgranulin A / Q000097:blood / Q000378:metabolism*; D040502:Calgranulin B / Q000097:blood / Q000378:metabolism*; D005260:Female; D006801:Humans; D007249:Inflammation / Q000276:immunology; D019570:Inhalation Exposure; D008070:Lipopolysaccharides / Q000276:immunology*; D018655:Lymphocyte Count; D008214:Lymphocytes; D008264:Macrophages / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism; D015203:Reproducibility of Results; D012137:Respiratory System / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D013183:Sputum / Q000166:cytology; D055815:Young Adult
D015415:Biomarkers; D040501:Calgranulin A; D040502:Calgranulin B; D008070:Lipopolysaccharides