Faculty Opinions recommendation of Increased airway epithelial Na+ absorption produces cystic fibrosis-like lung disease in mice.

Abstract Background Defective chloride transport in airway epithelial cells (AECs) and the associated lung disease are the main causes of morbidity and early mortality in cystic fibrosis (CF). Abnormal airway iron homeostasis and the presence of lipid peroxidation products, indicative of oxidative stress, are features of CF lung disease. Results Here, we report that CF AECs (IB3-1) are susceptible to ferroptosis, a type of cell death associated with iron accumulation and lipid peroxidation. Compared to isogenic CFTR corrected cells (C38), the IB3-1 cells showed increased susceptibility to cell death upon exposure to iron in the form of ferric ammonium citrate (FAC) and the ferroptosis inducer, erastin. This phenotype was accompanied by accumulation of intracellular ferrous iron and lipid peroxides and the extracellular release of malondialdehyde, all indicative of redox stress, and increased levels of lactate dehydrogenase in the culture supernatant, indicating enhanced cell injury. The ferric iron chelator deferoxamine (DFO) and the lipophilic antioxidant ferrostatin-1 inhibited FAC and erastin induced ferroptosis in IB3-1 cells. Glutathione peroxidase 4 (GPX4) expression was decreased in IB3-1 cells treated with FAC and erastin, but was unchanged in C38 AECs. Necroptosis appeared to be involved in the enhanced susceptibility of IB3-1 AECs to ferroptosis, as evidenced by partial cell death rescue with necroptosis inhibitors and enhanced mixed lineage kinase domain-like (MLKL) localisation to the plasma membrane. Conclusion These studies suggest that the increased susceptibility of CF AECs to ferroptosis is linked to abnormal intracellular ferrous iron accumulation and reduced antioxidant defences. In addition, the process of ferroptotic cell death in CF AECs does not appear to be a single entity and for the first time we describe necroptosis as a potential contributory factor. Iron chelation and antioxidant treatments may be promising therapeutic interventions in cystic fibrosis. Graphical Abstract

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Update on Calcium Signaling in Cystic Fibrosis Lung Disease

Frontiers in Pharmacology ◽

10.3389/fphar.2021.581645 ◽

2021 ◽

Vol 12 ◽

Author(s):

Alessandro Rimessi ◽

Veronica A. M. Vitto ◽

Simone Patergnani ◽

Paolo Pinton

Keyword(s):

Cystic Fibrosis ◽

Lung Disease ◽

Immune Cells ◽

Cell Function ◽

Autosomal Recessive Disorder ◽

Airway Epithelial ◽

Cystic Fibrosis Lung Disease ◽

Relevant Role ◽

Intracellular Organelles

Cystic fibrosis (CF) is an autosomal recessive disorder characterized by mutations in the cystic fibrosis transmembrane conductance regulator gene, which causes multifunctional defects that preferentially affect the airways. Abnormal viscosity of mucus secretions, persistent pathogen infections, hyperinflammation, and lung tissue damage compose the classical pathological manifestation referred to as CF lung disease. Among the multifunctional defects associated with defective CFTR, increasing evidence supports the relevant role of perturbed calcium (Ca2+) signaling in the pathophysiology of CF lung disease. The Ca2+ ion is a critical player in cell functioning and survival. Its intracellular homeostasis is maintained by a fine balance between channels, transporters, and exchangers, mediating the influx and efflux of the ion across the plasma membrane and the intracellular organelles. An abnormal Ca2+ profile has been observed in CF cells, including airway epithelial and immune cells, with heavy repercussions on cell function, viability, and susceptibility to pathogens, contributing to proinflammatory overstimulation, organelle dysfunction, oxidative stress, and excessive cytokines release in CF lung. This review discusses the role of Ca2+ signaling in CF and how its dysregulation in airway epithelial and immune cells contributes to hyperinflammation in the CF lung. Finally, we provide an outlook on the therapeutic options that target the Ca2+ signaling to treat the CF lung disease.

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A molecular atlas of proximal airway identifies subsets of known airway cell types revealing details of the unique molecular pathogenesis of Cystic Fibrosis

10.1101/2020.05.01.072876 ◽

2020 ◽

Author(s):

Gianni Carraro ◽

Justin Langerman ◽

Shan Sabri ◽

Zareeb Lorenzana ◽

Arunima Purkayastha ◽

...

Keyword(s):

Cystic Fibrosis ◽

Lung Disease ◽

Autosomal Recessive Disorder ◽

Cell Types ◽

Airway Disease ◽

Transmembrane Conductance Regulator ◽

Basal Cells ◽

Airway Epithelial ◽

Polarized Epithelia ◽

End Stage

Introduction/AbstractCystic fibrosis (CF) is a lethal autosomal recessive disorder that afflicts in excess of 70,000 people globally. People with CF experience multi-organ dysfunction resulting from aberrant electrolyte transport across polarized epithelia due to mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CF-related lung disease is by far the most significant determinant of morbidity and mortality. In this study we report results from a multi-institute consortium in which single cell transcriptomics were applied to define disease-related changes to the proximal airway of CF donors (n=19) undergoing transplantation for end-stage lung disease compared to the proximal airway of previously healthy lung donors (n=19). We found that all major airway epithelial cell types were conserved between control and CF donors. Disease-dependent differences were observed, including an overabundance of epithelial cells transitioning to specialized ciliated and secretory cell subtypes coupled with an unexpected decrease in cycling basal cells. This study developed a molecular atlas of the proximal airway epithelium that will provide insights for the development of new targeted therapies for CF airway disease.

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Airway Epithelial Inflammation In Vitro Augments the Rescue of Mutant CFTR by Current CFTR Modulator Therapies

Frontiers in Pharmacology ◽

10.3389/fphar.2021.628722 ◽

2021 ◽

Vol 12 ◽

Author(s):

Martina Gentzsch ◽

Deborah M. Cholon ◽

Nancy L. Quinney ◽

Mary E. B. Martino ◽

John T. Minges ◽

...

Keyword(s):

Cystic Fibrosis ◽

Lung Disease ◽

Early Stage ◽

Apical Surface ◽

Airway Epithelial ◽

Inflammatory Status ◽

Processing Defect ◽

Epithelial Cultures ◽

Epithelial Inflammation ◽

The Impact

In cystic fibrosis (CF), defective biogenesis and activity of the cystic fibrosis transmembrane conductance regulator (CFTR) leads to airway dehydration and impaired mucociliary clearance, resulting in chronic airway infection and inflammation. The most common CFTR mutation, F508del, results in a processing defect in which the protein is retained in the endoplasmic reticulum and does not reach the apical surface. CFTR corrector compounds address this processing defect to promote mutant CFTR transfer to the apical membrane. When coupled with potentiators to increase CFTR channel activity, these drugs yield significant clinical benefits in CF patients carrying the F508del mutation. However, processing of CFTR and other proteins can be influenced by environmental factors such as inflammation, and the impact of airway inflammation on pharmacological activity of CFTR correctors is not established. The present study evaluated CFTR-rescuing therapies in inflamed CF airway epithelial cultures, utilizing models that mimic the inflammatory environment of CF airways. Primary bronchial epithelial cultures from F508del/F508del CF patients were inflamed by mucosal exposure to one of two inflammatory stimuli: 1) supernatant from mucopurulent material from CF airways with advanced lung disease, or 2) bronchoalveolar lavage fluid from pediatric CF patients. Cultures inflamed with either stimulus exhibited augmented F508del responses following therapy with correctors VX-809 or VX-661, and overcame the detrimental effects of chronic exposure to the CFTR potentiator VX-770. Remarkably, even the improved CFTR rescue responses resulting from a clinically effective triple therapy (VX-659/VX-661/VX-770) were enhanced by epithelial inflammation. Thus, the airway inflammatory milieu from late- and early-stage CF lung disease improves the efficacy of CFTR modulators, regardless of the combination therapy used. Our findings suggest that pre-clinical evaluation of CFTR corrector therapies should be performed under conditions mimicking the native inflammatory status of CF airways, and altering the inflammatory status of CF airways may change the efficacy of CFTR modulator therapies.

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