Genome-wide profiling identifies epithelial cell genes associated with asthma and with treatment response to corticosteroids.
Airway inflammation and epithelial remodeling are two key features of asthma. IL-13 and other cytokines produced during T helper type 2 cell-driven allergic inflammation contribute to airway epithelial goblet cell metaplasia and may alter epithelial-mesenchymal signaling, leading to increased subepithelial fibrosis or hyperplasia of smooth muscle. The beneficial effects of corticosteroids in asthma could relate to their ability to directly or indirectly decrease epithelial cell activation by inflammatory cells and cytokines. To identify markers of epithelial cell dysfunction and the effects of corticosteroids on epithelial cells in asthma, we studied airway epithelial cells collected from asthmatic subjects enrolled in a randomized controlled trial of inhaled corticosteroids, from healthy subjects and from smokers (disease control). By using gene expression microarrays, we found that chloride channel, calcium-activated, family member 1 (CLCA1), periostin, and serine peptidase inhibitor, clade B (ovalbumin), member 2 (serpinB2) were up-regulated in asthma but not in smokers. Corticosteroid treatment down-regulated expression of these three genes and markedly up-regulated expression of FK506-binding protein 51 (FKBP51). Whereas high baseline expression of CLCA1, periostin, and serpinB2 was associated with a good clinical response to corticosteroids, high expression of FKBP51 was associated with a poor response. By using airway epithelial cells in culture, we found that IL-13 increased expression of CLCA1, periostin, and serpinB2, an effect that was suppressed by corticosteroids. Corticosteroids also induced expression of FKBP51. Taken together, our findings show that airway epithelial cells in asthma have a distinct activation profile and identify direct and cell-autonomous effects of corticosteroid treatment on airway epithelial cells that relate to treatment responses and can now be the focus of specific mechanistic studies.
Woodruff
Prescott G
PG
Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of California, San Francisco, CA 94143, USA.
Boushey
Homer A
HA
Dolganov
Gregory M
GM
Barker
Chris S
CS
Yang
Yee Hwa
YH
Donnelly
Samantha
S
Ellwanger
Almut
A
Sidhu
Sukhvinder S
SS
Dao-Pick
Trang P
TP
Pantoja
Carlos
C
Erle
David J
DJ
Yamamoto
Keith R
KR
Fahy
John V
JV
D000280:Administration, Inhalation; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy* / Q000235:genetics* / Q000473:pathology; D001999:Bronchoscopy; D015815:Cell Adhesion Molecules / Q000235:genetics; D018118:Chloride Channels / Q000235:genetics; D004847:Epithelial Cells / Q000473:pathology / Q000502:physiology*; D020869:Gene Expression Profiling; D015894:Genome, Human; D006801:Humans; D006967:Hypersensitivity; D007249:Inflammation / Q000235:genetics / Q000503:physiopathology; D020411:Oligonucleotide Array Sequence Analysis; D012016:Reference Values; D015843:Serpins / Q000235:genetics; D012907:Smoking / Q000473:pathology
D000305:Adrenal Cortex Hormones; C492109:CLCA1 protein, human; D015815:Cell Adhesion Molecules; D018118:Chloride Channels; C512835:POSTN protein, human; D015843:Serpins; C434683:serpin-2