Gene expression and immunolocalization of 15-lipoxygenase isozymes in the airway mucosa of smokers with chronic bronchitis.
15-lipoxygenase (15-LO) has been implicated in the inflammation of chronic bronchitis (CB), but it is unclear which of its isoforms, 15-LOa or 15-LOb, is primarily involved. To detect 15-LO gene (mRNA) and protein expression, we have applied in situ hybridization (ISH) and immunohistochemistry (IHC), respectively, to bronchial biopsies obtained from 7 healthy nonsmokers (HNS), 5 healthy smokers (HS), and 8 smokers with CB, and additionally include the airways of lungs resected from 11 asymptomatic smokers (AS) and 11 smokers with CB. Compared with HNS, biopsies in CB demonstrated increased numbers of 15-LOa mRNA+ cells (median: HNS = 31.3/mm(2) versus CB = 84.9/mm(2), P < 0.01) and protein+ cells (HNS = 2.9/mm(2) versus CB = 32.1/mm(2), P < 0.01). The HS group also showed a significant increase in protein+ cells (HNS = 2.9/mm(2) versus HS = 14/mm(2), P < 0.05). In the resected airways, 15-LOa protein+ cells in the submucosal glands of the CB group were more numerous than in the AS group (AS = 33/mm(2) versus CB = 208/mm(2); P < 0.001). 15-LOa mRNA+ and protein+ cells consistently outnumbered 15-LOb by approximately 7- and 5-fold, respectively (P < 0.01). Quantitative reverse transcriptase polymerase chain reaction of complementary biopsies confirmed the increased levels of 15-LOa in CB compared with that in either HNS or HS (P < 0.05). There was no difference between the subject groups with respect to 15-LOb expression. The numbers of cells expressing mRNA for 15-LOa in CB showed a positive association with those expressing interleukin (IL)-4 mRNA (r = 0.80; P < 0.01). We conclude that the upregulation of 15-LO activity in the airways of HS and of smokers with CB primarily involves the 15-LOa isoform: the functional consequences of its association the upregulation of IL-4 in chronic bronchitis requires further study.
Zhu
Jie
J
Lung Pathology, Department of Gene Therapy, Imperial College at the Royal Brompton Hospital, London, UK.
Kilty
Iain
I
Granger
Helen
H
Gamble
Elizabeth
E
Qiu
Yu Sheng
YS
Hattotuwa
Keith
K
Elston
Will
W
Liu
Wai L
WL
Oliva
Alessandro
A
Pauwels
Romain A
RA
Kips
Johan C
JC
De Rose
Virginia
V
Barnes
Neil
N
Yeadon
Michael
M
Jenkinson
Stephen
S
Jeffery
Peter K
PK
D000328:Adult; D000368:Aged; D001093:Arachidonate 15-Lipoxygenase / Q000032:analysis* / Q000235:genetics*; D001706:Biopsy; D029481:Bronchitis, Chronic / Q000201:enzymology* / Q000209:etiology / Q000473:pathology; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007527:Isoenzymes / Q000032:analysis* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis; D020545:Respiratory Mucosa / Q000201:enzymology / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012907:Smoking / Q000009:adverse effects
D007527:Isoenzymes; D012333:RNA, Messenger; D001093:Arachidonate 15-Lipoxygenase