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.

Original publication

DOI

10.4049/jimmunol.1201404

Type

Journal

J Immunol

Publication Date

01/02/2013

Volume

190

Pages

1227 - 1238

Keywords

Anti-Inflammatory Agents, Antimicrobial Cationic Peptides, Autophagy, Cell Line, Child, Cystic Fibrosis, Cytokines, Epithelial Cells, Escherichia coli Proteins, Flagellin, Gene Expression Regulation, Humans, Inflammation, Leukocytes, Mononuclear, Lung, Lysosomes, Macrolides, Microtubule-Associated Proteins, Models, Immunological, Protein Kinases, Proto-Oncogene Proteins c-akt, Signal Transduction, Systems Biology, Transcription, Genetic