15-Lipoxygenase expression and 15(S)-hydroxyeicoisatetraenoic acid release and reincorporation in induced sputum of asthmatic subjects.
BACKGROUND
Recent evidence shows that 15(S)-hydroxy-eicoisatetraenoic acid (15[S]-HETE) can be released and rapidly reincorporated into cellular lipids. These mechanisms exert several immunoregulatory functions that may be relevant in airway inflammation.


OBJECTIVE
Our purpose was to evaluate the levels of both soluble and cell-associated 15(S)-HETE and to examine 15-lipoxygenase (15-LO) messenger RNA (mRNA) expression in sputum samples obtained from 10 control and 18 asthmatic subjects.


METHODS
Levels of 15(S)-HETE were measured by reverse-phase HPLC separation followed by RIA in supernatants and in cell membrane-extracted phospholipids after acid hydrolysis. 15-LO mRNA was evaluated by primed in situ hybridization (PRINS). Combined immunocytochemistry and PRINS was used to identify the phenotype of cells bearing 15-LO transcripts.


RESULTS
Levels of both soluble and cell-associated 15(S)-HETE were higher in asthmatic than in control subjects (P <.0001). The percentage of cells expressing 15-LO mRNA was higher in asthmatic than in control subjects (P <.01). On double staining for specific cell-type markers and 15-LO mRNA, macrophages were the major source for 15-LO.


CONCLUSIONS
This study shows that the induced sputum technique allows the evaluation of 15-LO activity and that soluble, cell-associated 15(S)-HETE and 15-LO levels are higher in asthmatic than in control subjects. In addition, this study indicates that, in induced sputum, airway macrophages are the major source of 15(S)-HETE in asthma.
Profita
M
M
Istituto di Fisiopatologia Respiratoria, Consiglio delle Ricerche, and the Istituto di Medicina Generale e Pneumologia, University of Palermo, Palermo, Italy.
Sala
A
A
Riccobono
L
L
Paternò
A
A
Mirabella
A
A
Bonanno
A
A
Guerrera
D
D
Pace
E
E
Bonsignore
G
G
Bousquet
J
J
Vignola
A M
AM
D000328:Adult; D000368:Aged; D001093:Arachidonate 15-Lipoxygenase / Q000235:genetics*; D001249:Asthma / Q000378:metabolism*; D002452:Cell Count; D005541:Forced Expiratory Volume; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D012463:Saliva / Q000166:cytology; D012995:Solubility; D013183:Sputum / Q000737:chemistry / Q000166:cytology / Q000201:enzymology
D006893:Hydroxyeicosatetraenoic Acids; D012333:RNA, Messenger; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid; D001093:Arachidonate 15-Lipoxygenase