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  2. CFTR Correctors and Antioxidants Partially Normalize Lipid Imbalance but not Abnormal Basal Inflammatory Cytokine Profile in CF Bronchial Epithelial Cells

CFTR Correctors and Antioxidants Partially Normalize Lipid Imbalance but not Abnormal Basal Inflammatory Cytokine Profile in CF Bronchial Epithelial Cells

  • Front Physiol. 2021 Feb 4;12:619442. doi: 10.3389/fphys.2021.619442.
Mieke Veltman 1 2 Juan B De Sanctis 3 Marta Stolarczyk 1 Nikolai Klymiuk 4 5 Andrea Bähr 4 5 Rutger W Brouwer 1 6 Edwin Oole 1 6 Juhi Shah 7 Tomas Ozdian 3 Jie Liao 8 Carolina Martini 8 Danuta Radzioch 7 John W Hanrahan 7 8 Bob J Scholte 1 2
Affiliations

Affiliations

  • 1 Cell Biology Department, Erasmus Medical Center, Rotterdam, Netherlands.
  • 2 Pediatric Pulmonology, Sophia Children's Hospital, Erasmus Medical Center, Rotterdam, Netherlands.
  • 3 Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacký University, Olomouc, Czechia.
  • 4 Large Animal Models for Cardiovascular Research, TU Munich, Munich, Germany.
  • 5 Center for Innovative Medical Models, LMU Munich, Munich, Germany.
  • 6 Center for Biomics, Erasmus Medical Center, Rotterdam, Netherlands.
  • 7 Department of Medicine, The Research Institute of the McGill University Health Centre, McGill University, Montreal, QC, Canada.
  • 8 Department of Physiology, CF Translational Research Centre, McGill University, Montreal, QC, Canada.
Abstract

A deficiency in cystic fibrosis transmembrane conductance regulator (CFTR) function in CF leads to chronic lung disease. CF is associated with abnormalities in fatty acids, ceramides, and Cholesterol, their relationship with CF lung pathology is not completely understood. Therefore, we examined the impact of CFTR deficiency on lipid metabolism and pro-inflammatory signaling in airway epithelium using mass spectrometric, protein array. We observed a striking imbalance in fatty acid and ceramide metabolism, associated with chronic oxidative stress under basal conditions in CF mouse lung and well-differentiated bronchial epithelial cell cultures of CFTR knock out pig and CF patients. Cell-autonomous features of all three CF models included high ratios of ω-6- to ω-3-polyunsaturated fatty acids and of long- to very long-chain ceramide species (LCC/VLCC), reduced levels of total ceramides and ceramide precursors. In addition to the retinoic acid analog fenretinide, the anti-oxidants glutathione (GSH) and deferoxamine partially corrected the lipid profile indicating that oxidative stress may promote the lipid abnormalities. CFTR-targeted modulators reduced the lipid imbalance and oxidative stress, confirming the CFTR dependence of lipid ratios. However, despite functional correction of CF cells up to 60% of non-CF in Ussing chamber experiments, a 72-h triple compound treatment (elexacaftor/tezacaftor/ivacaftor surrogate) did not completely normalize lipid imbalance or oxidative stress. Protein array analysis revealed differential expression and shedding of Cytokines and Growth Factors from CF epithelial cells compared to non-CF cells, consistent with sterile inflammation and tissue remodeling under basal conditions, including enhanced secretion of the neutrophil activator CXCL5, and the T-cell activator CCL17. However, treatment with antioxidants or CFTR modulators that mimic the approved combination therapies, ivacaftor/lumacaftor and ivacaftor/tezacaftor/elexacaftor, did not effectively suppress the inflammatory phenotype. We propose that CFTR deficiency causes oxidative stress in CF airway epithelium, affecting multiple bioactive lipid metabolic pathways, which likely play a role in CF lung disease progression. A combination of anti-oxidant, anti-inflammatory and CFTR targeted therapeutics may be required for full correction of the CF phenotype.

Keywords

bronchial epithelial cell; ceramide species; cystic fibrosis; cystic fibrosis transmembrane conductance regulator corrector therapy; cytokine array; lipidomics; oxidative stress; polyunsaturated (essential) fatty acids.

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