Abstract
Accumulation of unwanted/misfolded proteins in aggregates has been observed in airways of patients with cystic fibrosis (CF), a life-threatening genetic disorder caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR). Here we show how the defective CFTR results in defective autophagy and decreases the clearance of aggresomes. Defective CFTR-induced upregulation of reactive oxygen species (ROS) and tissue transglutaminase (TG2) drive the crosslinking of beclin 1, leading to sequestration of phosphatidylinositol-3-kinase (PI(3)K) complex III and accumulation of p62, which regulates aggresome formation. Both CFTR knockdown and the overexpression of green fluorescent protein (GFP)-tagged-CFTR(F508del) induce beclin 1 downregulation and defective autophagy in non-CF airway epithelia through the ROS-TG2 pathway. Restoration of beclin 1 and autophagy by either beclin 1 overexpression, cystamine or antioxidants rescues the localization of the beclin 1 interactome to the endoplasmic reticulum and reverts the CF airway phenotype in vitro, in vivo in Scnn1b-transgenic and Cftr(F508del) homozygous mice, and in human CF nasal biopsies. Restoring beclin 1 or knocking down p62 rescued the trafficking of CFTR(F508del) to the cell surface. These data link the CFTR defect to autophagy deficiency, leading to the accumulation of protein aggregates and to lung inflammation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Acetylcysteine / pharmacology
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Acetylcysteine / therapeutic use
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Adaptor Proteins, Signal Transducing / genetics
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Adaptor Proteins, Signal Transducing / metabolism
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Adolescent
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Adult
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Animals
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Antioxidants / pharmacology
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Antioxidants / therapeutic use
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Apoptosis Regulatory Proteins / genetics
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Apoptosis Regulatory Proteins / metabolism
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Autophagy* / drug effects
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Autophagy* / genetics
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Beclin-1
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Cell Line
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Cystamine / pharmacology
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Cystamine / therapeutic use
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Cystic Fibrosis / drug therapy
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Cystic Fibrosis / genetics
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Cystic Fibrosis / metabolism*
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Cystic Fibrosis Transmembrane Conductance Regulator / antagonists & inhibitors
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Cystic Fibrosis Transmembrane Conductance Regulator / genetics
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Cystic Fibrosis Transmembrane Conductance Regulator / metabolism*
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Epithelial Sodium Channels / genetics
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GTP-Binding Proteins
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Heat-Shock Proteins / metabolism
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Humans
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Inflammation / metabolism
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Mice
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Mice, Inbred CFTR
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Mice, Inbred Strains
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Mice, Transgenic
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Microtubule-Associated Proteins / metabolism
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Models, Biological
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Nasal Polyps / drug therapy
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Nasal Polyps / metabolism
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Organometallic Compounds / pharmacology
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Phosphatidylinositol 3-Kinases / metabolism
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Phosphoinositide-3 Kinase Inhibitors
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Protein Binding / physiology
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Protein Glutamine gamma Glutamyltransferase 2
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Protein Transport / genetics
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Reactive Oxygen Species / antagonists & inhibitors
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Reactive Oxygen Species / metabolism*
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Respiratory Mucosa / cytology
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Respiratory Mucosa / drug effects
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Respiratory Mucosa / metabolism
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Salicylates / pharmacology
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Sequestosome-1 Protein
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Small Ubiquitin-Related Modifier Proteins / metabolism
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Transglutaminases / genetics
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Transglutaminases / metabolism
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Young Adult
Substances
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Adaptor Proteins, Signal Transducing
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Antioxidants
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Apoptosis Regulatory Proteins
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BECN1 protein, human
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Beclin-1
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Becn1 protein, mouse
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EUK-134
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Epithelial Sodium Channels
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Heat-Shock Proteins
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MAP1LC3A protein, human
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Map1lc3b protein, mouse
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Membrane Proteins
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Microtubule-Associated Proteins
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Organometallic Compounds
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Phosphoinositide-3 Kinase Inhibitors
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Reactive Oxygen Species
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SQSTM1 protein, human
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Salicylates
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Scnn1b protein, mouse
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Sequestosome-1 Protein
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Small Ubiquitin-Related Modifier Proteins
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Sqstm1 protein, mouse
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Cystic Fibrosis Transmembrane Conductance Regulator
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Protein Glutamine gamma Glutamyltransferase 2
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Transglutaminases
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GTP-Binding Proteins
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Cystamine
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Acetylcysteine