title: Cigarette smoke exposure induces CFTR internalization and insolubility, leading to airway surface liquid dehydration.
abstract: Cigarette smoke (CS) exposure induces mucus obstruction and the development of chronic bronchitis (CB). While many of these responses are determined genetically, little is known about the effects CS can exert on pulmonary epithelia at the protein level. We, therefore, tested the hypothesis that CS exerts direct effects on the CFTR protein, which could impair airway hydration, leading to the mucus stasis characteristic of both cystic fibrosis and CB. In vivo and in vitro studies demonstrated that CS rapidly decreased CFTR activity, leading to airway surface liquid (ASL) volume depletion (i.e., dehydration). Further studies revealed that CS induced internalization of CFTR. Surprisingly, CS-internalized CFTR did not colocalize with lysosomal proteins. Instead, the bulk of CFTR shifted to a detergent-resistant fraction within the cell and colocalized with the intermediate filament vimentin, suggesting that CS induced CFTR movement into an aggresome-like, perinuclear compartment. To test whether airway dehydration could be reversed, we used hypertonic saline (HS) as an osmolyte to rehydrate ASL. HS restored ASL height in CS-exposed, dehydrated airway cultures. Similarly, inhaled HS restored mucus transport and increased clearance in patients with CB. Thus, we propose that CS exposure rapidly impairs CFTR function by internalizing CFTR, leading to ASL dehydration, which promotes mucus stasis and a failure of mucus clearance, leaving smokers at risk for developing CB. Furthermore, our data suggest that strategies to rehydrate airway surfaces may provide a novel form of therapy for patients with CB.
authors: Cystic Fibrosis/Pulmonary Research and Treatment Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors: Lucy A
authors: LA
authors: Clunes
authors: Catrin M
authors: CM
authors: Davies
authors: Raymond D
authors: RD
authors: Coakley
authors: Andrei A
authors: AA
authors: Aleksandrov
authors: Ashley G
authors: AG
authors: Henderson
authors: Kirby L
authors: KL
authors: Zeman
authors: Erin N
authors: EN
authors: Worthington
authors: Martina
authors: M
authors: Gentzsch
authors: Silvia M
authors: SM
authors: Kreda
authors: Deborah
authors: D
authors: Cholon
authors: William D
authors: WD
authors: Bennett
authors: John R
authors: JR
authors: Riordan
authors: Richard C
authors: RC
authors: Boucher
authors: Robert
authors: R
authors: Tarran
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001483:Base Sequence; D001693:Biological Transport, Active; D001834:Body Water / Q000378:metabolism; D029481:Bronchitis, Chronic / Q000209:etiology / Q000378:metabolism; D016022:Case-Control Studies; D002478:Cells, Cultured; D006224:Cricetinae; D003550:Cystic Fibrosis / Q000209:etiology / Q000378:metabolism / Q000628:therapy; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D005260:Female; D006801:Humans; D008168:Lung / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009079:Mucociliary Clearance; D020545:Respiratory Mucosa / Q000378:metabolism; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D012906:Smoke / Q000009:adverse effects; D012907:Smoking / Q000009:adverse effects* / Q000378:metabolism*; D012995:Solubility
chemical_list: C505032:CFTR protein, human; D017931:DNA Primers; D012462:Saline Solution, Hypertonic; D012906:Smoke; D019005:Cystic Fibrosis Transmembrane Conductance Regulator