title: Targeting autophagy as a novel strategy for facilitating the therapeutic action of potentiators on ΔF508 cystic fibrosis transmembrane conductance regulator.
abstract: Channel activators (potentiators) of cystic fibrosis (CF) transmembrane conductance regulator (CFTR), can be used for the treatment of the small subset of CF patients that carry plasma membrane-resident CFTR mutants. However, approximately 90% of CF patients carry the misfolded ΔF508-CFTR and are poorly responsive to potentiators, because ΔF508-CFTR is intrinsically unstable at the plasma membrane (PM) even if rescued by pharmacological correctors. We have demonstrated that human and mouse CF airways are autophagy deficient due to functional sequestration of BECN1 and that the tissue transglutaminase-2 inhibitor, cystamine, or antioxidants restore BECN1-dependent autophagy and reduce SQSTM1/p62 levels, thus favoring ΔF508-CFTR trafficking to the epithelial surface. Here, we investigated whether these treatments could facilitate the beneficial action of potentiators on ΔF508-CFTR homozygous airways. Cystamine or the superoxide dismutase (SOD)/catalase-mimetic EUK-134 stabilized ΔF508-CFTR at the plasma membrane of airway epithelial cells and sustained the expression of CFTR at the epithelial surface well beyond drug withdrawal, overexpressing BECN1 and depleting SQSTM1. This facilitates the beneficial action of potentiators in controlling inflammation in ex vivo ΔF508-CFTR homozygous human nasal biopsies and in vivo in mouse ΔF508-CFTR lungs. Direct depletion of Sqstm1 by shRNAs in vivo in ΔF508-CFTR mice synergized with potentiators in sustaining surface CFTR expression and suppressing inflammation. Cystamine pre-treatment restored ΔF508-CFTR response to the CFTR potentiators genistein, Vrx-532 or Vrx-770 in freshly isolated brushed nasal epithelial cells from ΔF508-CFTR homozygous patients. These findings delineate a novel therapeutic strategy for the treatment of CF patients with the ΔF508-CFTR mutation in which patients are first treated with cystamine and subsequently pulsed with CFTR potentiators.
authors.affiliation: European Institute for Research in Cystic Fibrosis, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Luciani
authors.forename: Valeria Rachela
authors.initials: VR
authors.lastname: Villella
authors.forename: Speranza
authors.initials: S
authors.lastname: Esposito
authors.forename: Manuela
authors.initials: M
authors.lastname: Gavina
authors.forename: Ilaria
authors.initials: I
authors.lastname: Russo
authors.forename: Marco
authors.initials: M
authors.lastname: Silano
authors.forename: Stefano
authors.initials: S
authors.lastname: Guido
authors.forename: Massimo
authors.initials: M
authors.lastname: Pettoello-Mantovani
authors.forename: Rosa
authors.initials: R
authors.lastname: Carnuccio
authors.forename: Bob
authors.initials: B
authors.lastname: Scholte
authors.forename: Antonella
authors.initials: A
authors.lastname: De Matteis
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Maiuri
authors.forename: Valeria
authors.initials: V
authors.lastname: Raia
authors.forename: Alberto
authors.initials: A
authors.lastname: Luini
authors.forename: Guido
authors.initials: G
authors.lastname: Kroemer
authors.forename: Luigi
authors.initials: L
authors.lastname: Maiuri
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000293:Adolescent; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001343:Autophagy / Q000187:drug effects; D000071186:Beclin-1; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002648:Child; D003538:Cystamine / Q000494:pharmacology / Q000627:therapeutic use; D003550:Cystic Fibrosis / Q000188:drug therapy / Q000473:pathology; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D005260:Female; D019833:Genistein / Q000494:pharmacology; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000473:pathology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008168:Lung / Q000187:drug effects / Q000473:pathology; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D058990:Molecular Targeted Therapy; D009297:Nasal Mucosa / Q000187:drug effects / Q000473:pathology; D009298:Nasal Polyps / Q000473:pathology; D009942:Organometallic Compounds / Q000494:pharmacology / Q000627:therapeutic use; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D012459:Salicylates / Q000494:pharmacology / Q000627:therapeutic use; D000071456:Sequestosome-1 Protein
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000975:Antioxidants; D051017:Apoptosis Regulatory Proteins; C491997:BECN1 protein, human; D000071186:Beclin-1; C433928:EUK-134; D006360:Heat-Shock Proteins; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D009942:Organometallic Compounds; D012459:Salicylates; D000071456:Sequestosome-1 Protein; C101343:Sqstm1 protein, mouse; C000717608:TGM2 protein, human; C093349:cystic fibrosis transmembrane conductance regulator delta F508; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D019833:Genistein; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D003538:Cystamine