Dataset Information

CFTR Modulators Restore Acidification of Autophago-Lysosomes and Bacterial Clearance in Cystic Fibrosis Macrophages.

ABSTRACT: Cystic fibrosis (CF) human and mouse macrophages are defective in their ability to clear bacteria such as Burkholderia cenocepacia. The autophagy process in CF (F508del) macrophages is halted, and the underlying mechanism remains unclear. Furthermore, the role of CFTR in maintaining the acidification of endosomal and lysosomal compartments in CF cells has been a subject of debate. Using 3D reconstruction of z-stack confocal images, we show that CFTR is recruited to LC3-labeled autophagosomes harboring B. cenocepacia. Using several complementary approaches, we report that CF macrophages display defective lysosomal acidification and degradative function for cargos destined to autophagosomes, whereas non-autophagosomal cargos are effectively degraded within acidic compartments. Notably, treatment of CF macrophages with CFTR modulators (tezacaftor/ivacaftor) improved the autophagy flux, lysosomal acidification and function, and bacterial clearance. In addition, CFTR modulators improved CFTR function as demonstrated by patch-clamp. In conclusion, CFTR regulates the acidification of a specific subset of lysosomes that specifically fuse with autophagosomes. Therefore, our study describes a new biological location and function for CFTR in autophago-lysosomes and clarifies the long-standing discrepancies in the field.

SUBMITTER: Badr A

PROVIDER: S-EPMC8890004 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature

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Publications

CFTR Modulators Restore Acidification of Autophago-Lysosomes and Bacterial Clearance in Cystic Fibrosis Macrophages.

Badr Asmaa A Eltobgy Mostafa M Krause Kathrin K Hamilton Kaitlin K Estfanous Shady S Daily Kylene P KP Abu Khweek Arwa A Hegazi Ahmad A Anne Midhun N K MNK Carafice Cierra C Robledo-Avila Frank F Saqr Youssra Y Zhang Xiaoli X Bonfield Tracey L TL Gavrilin Mikhail A MA Partida-Sanchez Santiago S Seveau Stephanie S Cormet-Boyaka Estelle E Amer Amal O AO

Frontiers in cellular and infection microbiology 20220216

Cystic fibrosis (CF) human and mouse macrophages are defective in their ability to clear bacteria such as <i>Burkholderia cenocepacia</i>. The autophagy process in CF (F508del) macrophages is halted, and the underlying mechanism remains unclear. Furthermore, the role of CFTR in maintaining the acidification of endosomal and lysosomal compartments in CF cells has been a subject of debate. Using 3D reconstruction of z-stack confocal images, we show that CFTR is recruited to LC3-labeled autophagoso ...[more]

PMID: 35252032

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Project description:Cystic fibrosis transmembrane conductance regulator (CFTR) modulators improve clinical outcomes with varied efficacies in patients with CF. However, the mutual effects of CFTR modulators and bacterial adaptation, together with antibiotic regimens, can influence clinical outcomes. We evaluated the effects of ivacaftor (IVA), lumacaftor (LUM), tezacaftor, elexacaftor, and a three-modulator combination of elexacaftor, tezacaftor, and ivacaftor (ETI), alone or combined with antibiotics, on sequential CF isolates. IVA and ETI showed direct antimicrobial activities against Staphylococcus aureus but not against Pseudomonas aeruginosa. Additive effects or synergies were observed between the CFTR modulators and antibiotics against both species, independently of adaptation to the CF lung. IVA and LUM were the most effective in potentiating antibiotic activity against S. aureus, while IVA and ETI enhanced mainly polymyxin activity against P. aeruginosa. Next, we evaluated the effect of P. aeruginosa pneumonia on the pharmacokinetics of IVA in mice. IVA and its metabolites in plasma, lung, and epithelial lining fluid were increased by P. aeruginosa infection. Thus, CFTR modulators can have direct antimicrobial properties and/or enhance antibiotic activity against initial and adapted S. aureus and P. aeruginosa isolates. Furthermore, bacterial infection impacts airway exposure to IVA, potentially affecting its efficacy. Our findings suggest optimizing host- and pathogen-directed therapies to improve efficacy for personalized treatment. IMPORTANCE CFTR modulators have been developed to correct and/or enhance CFTR activity in patients with specific cystic fibrosis (CF) genotypes. However, it is of great importance to identify potential off-targets of these novel therapies to understand how they affect lung physiology in CF. Since bacterial infections are one of the hallmarks of CF lung disease, the effects (if any) of CFTR modulators on bacteria could impact their efficacy. This work highlights a mutual interaction between CFTR modulators and opportunistic bacterial infections; in particular, it shows that (i) CFTR modulators have an antibacterial activity per se and influence antibiotic efficacy, and (ii) bacterial airway infections affect levels of CFTR modulators in the airways. These findings may help optimize host- and pathogen-directed drug regimens to improve the efficacy of personalized treatment.

Project description:Cystic fibrosis (CF) is an autosomal recessive genetic disease characterized by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR). CFTR is a chloride channel responsible for ion flow across epithelial surfaces of lung, sinuses, pancreas, intestine, and liver. Researchers have grouped CFTR genetic mutations into various protein defects: reduced protein synthesis (class 1 mutations), abnormal protein folding and maturation (class 2 mutation), and abnormal gating (class 3 mutation). These mutations usually present as severe forms of CF due to complete absence of CFTR at cell surfaces. Milder forms (eg, protein maturation and conductance defects, classes 4-6) present as less severe forms of CF related to the presence of CFTR at the cell surface. Differences in severity are directly due to CFTR function which is based on the severity of CFTR mutation. This knowledge has proven useful for designing therapy for individual mutations and mutation classes. The discovery and US Food and Drug Administration approval of Kalydeco® (ivacaftor) in early 2011 marked the beginning of a new era of therapies that are focused on improving defective CFTR protein function. However, due to its specificity for the G551D mutation, ivacaftor only benefitŝ5% of CF patients. Approximately 50% of CF patients have two copies of the F508Del mutation, while other CF patients carry only one copy of this gene. More recently, Orkambi®, a two compound medication composed of lumacaftor and ivacaftor, has provided the foundation necessary to further build on molecular concepts of: correction of trafficking, potentiation, and amplification of defective CFTR. These new concepts will form the basis of future CF therapies and extend CFTR treatment to almost 50% of CF patients. Evolving knowledge of the molecular mechanisms responsible for defective CFTR has prompted new research focused on "repair" of each phase of CFTR expression and function, thus creating a new class of combination "CFTR correctors" referred to as "triplet CFTR compounds." This article will review how patients can be selected and treated with these newer agents that are based on specific mutations. In the future, many CF practitioners have expectations that initiation of treatment for CF patients will occur simply by use of biomarkers of CFTR expression (eg, sweat chloride, nasal potential difference, rectal organoids) rather than testing for specific mutations. As continued research identifies biomarkers with greater specificity and which predict clinical response, therapies can potentially be tailored to individual responses.

Dataset Information

CFTR Modulators Restore Acidification of Autophago-Lysosomes and Bacterial Clearance in Cystic Fibrosis Macrophages.

Publications

CFTR Modulators Restore Acidification of Autophago-Lysosomes and Bacterial Clearance in Cystic Fibrosis Macrophages.

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