title: Rescue of dysfunctional autophagy attenuates hyperinflammatory responses from cystic fibrosis cells.
abstract: A hallmark feature of cystic fibrosis (CF) is progressive pulmonary obstruction arising from exaggerated host proinflammatory responses to chronic bacterial airway colonization. The mechanisms for these heightened inflammatory responses have been only partially characterized, hampering development of effective anti-inflammatory therapies. The aim of this study was to identify and validate novel dysfunctional processes or pathways driving the hyperinflammatory phenotype of CF cells using systems biology and network analysis to examine transcriptional changes induced by innate defense regulator (IDR)-1018, an anti-inflammatory peptide. IDR-1018 selectively attenuated hyperinflammatory cytokine production from CF airway cells and PBMCs stimulated with multiple bacterial ligands, including flagellin (FliC). Network analysis of CF cell transcriptional responses to FliC and IDR-1018 identified dysfunctional autophagy as the target of the peptide via modulation of upstream adenosine monophosphate-activated protein kinase (AMPK)-Akt signaling. After treatment with FliC, CF cells were found to have elevated levels of the autophagosome marker LC3-II, and GFP-LC3-transfected CF airway cells showed abnormal perinuclear accumulation of GFP(+) structures. In both instances, treatment of CF cells with IDR-1018 abolished the accumulation of LC3 induced by FliC. Furthermore, inhibition of autophagosome-lysosome fusion with bafilomycinA1 attenuated the anti-inflammatory and autophagosome-clearing effects of IDR-1018, as did a chemical inhibitor of Akt and an activator of AMPK. These findings were consistent with hypotheses generated in silico, demonstrating the utility of systems biology and network analysis approaches for providing pathway-level insights into CF-associated inflammation. Collectively, these data suggest that dysfunctional autophagosome clearance contributes to heightened inflammatory responses from CF transmembrane receptor mutant cells and highlight autophagy and AMPK-Akt signaling as novel anti-inflammatory targets in CF.
authors.affiliation: Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Mayer
authors.forename: Christoph J
authors.initials: CJ
authors.lastname: Blohmke
authors.forename: Reza
authors.initials: R
authors.lastname: Falsafi
authors.forename: Chris D
authors.initials: CD
authors.lastname: Fjell
authors.forename: Laurence
authors.initials: L
authors.lastname: Madera
authors.forename: Stuart E
authors.initials: SE
authors.lastname: Turvey
authors.forename: Robert E W
authors.initials: RE
authors.lastname: Hancock
mesh_terms: D000091162:AMP-Activated Protein Kinase Kinases; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology; D001343:Autophagy / Q000187:drug effects; D002460:Cell Line; D002648:Child; D003550:Cystic Fibrosis / Q000276:immunology / Q000473:pathology*; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics; D004847:Epithelial Cells / Q000187:drug effects / Q000276:immunology / Q000473:pathology*; D029968:Escherichia coli Proteins / Q000276:immunology; D005408:Flagellin; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007249:Inflammation; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D008168:Lung / Q000473:pathology*; D008247:Lysosomes / Q000187:drug effects / Q000502:physiology; D018942:Macrolides / Q000494:pharmacology; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis / Q000235:genetics; D018448:Models, Immunological; D011494:Protein Kinases / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects; D049490:Systems Biology; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D000893:Anti-Inflammatory Agents; D023181:Antimicrobial Cationic Peptides; D016207:Cytokines; D029968:Escherichia coli Proteins; C516095:FliC protein, E coli; D018942:Macrolides; C480860:Map1lc3b protein, mouse; D008869:Microtubule-Associated Proteins; C555052:innate defense regulating peptide 1018; D005408:Flagellin; C040929:bafilomycin A1; D011494:Protein Kinases; C514862:Akt1 protein, mouse; D051057:Proto-Oncogene Proteins c-akt; D000091162:AMP-Activated Protein Kinase Kinases