title: Epithelial EGF receptor signaling mediates airway hyperreactivity and remodeling in a mouse model of chronic asthma.
abstract: Increases in the epidermal growth factor receptor (EGFR) have been associated with the severity of airway thickening in chronic asthmatic subjects, and EGFR signaling is induced by asthma-related cytokines and inflammation. The goal of this study was to determine the role of EGFR signaling in a chronic allergic model of asthma and specifically in epithelial cells, which are increasingly recognized as playing an important role in asthma. EGFR activation was assessed in mice treated with intranasal house dust mite (HDM) for 3 wk. EGFR signaling was inhibited in mice treated with HDM for 6 wk, by using either the drug erlotinib or a genetic approach that utilizes transgenic mice expressing a mutant dominant negative epidermal growth factor receptor in the lung epithelium (EGFR-M mice). Airway hyperreactivity (AHR) was assessed by use of a flexiVent system after increasing doses of nebulized methacholine. Airway smooth muscle (ASM) thickening was measured by morphometric analysis. Sensitization to HDM (IgG and IgE), inflammatory cells, and goblet cell changes were also assessed. Increased EGFR activation was detected in HDM-treated mice, including in bronchiolar epithelial cells. In mice exposed to HDM for 6 wk, AHR and ASM thickening were reduced after erlotinib treatment and in EGFR-M mice. Sensitization to HDM and inflammatory cell counts were similar in all groups, except neutrophil counts, which were lower in the EGFR-M mice. Goblet cell metaplasia with HDM treatment was reduced by erlotinib, but not in EGFR-M transgenic mice. This study demonstrates that EGFR signaling, especially in the airway epithelium, plays an important role in mediating AHR and remodeling in a chronic allergic asthma model.
authors.affiliation: Division of Pulmonary Biology, Cincinnati Children's Hospital, OH 45229, USA. tim.lecras@cchmc.org
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Le Cras
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Acciani
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Mushaben
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: Kramer
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Pastura
authors.forename: William D
authors.initials: WD
authors.lastname: Hardie
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Korfhagen
authors.forename: Umasundari
authors.initials: U
authors.lastname: Sivaprasad
authors.forename: Mark
authors.initials: M
authors.lastname: Ericksen
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Gibson
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Holtzman
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Whitsett
authors.forename: Gurjit K Khurana
authors.initials: GK
authors.lastname: Hershey
mesh_terms: D056151:Airway Remodeling / Q000502:physiology*; D000818:Animals; D001249:Asthma / Q000150:complications / Q000469:parasitology / Q000473:pathology / Q000503:physiopathology*; D016535:Bronchial Hyperreactivity / Q000150:complications* / Q000469:parasitology / Q000473:pathology / Q000503:physiopathology; D002908:Chronic Disease; D004195:Disease Models, Animal; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000201:enzymology* / Q000473:pathology; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020397:Goblet Cells / Q000473:pathology; D007249:Inflammation / Q000150:complications / Q000473:pathology; D008168:Lung / Q000469:parasitology / Q000473:pathology / Q000503:physiopathology; D008679:Metaplasia; D051379:Mice; D009130:Muscle, Smooth / Q000473:pathology; D039981:Pyroglyphidae / Q000502:physiology; D015398:Signal Transduction
chemical_list: D066246:ErbB Receptors