CFTR and cystic fibrosis: This proinflammatory phenotype of CF airway epithelial cells is likely due to a combination of different factors including 1) endoplasmic reticulum stress that develops because of the intracellular accumulation of misfolded CFTR proteins in case of certain CFTR mutations, impaired regulation of 2) ion transport and 3) intracellular signaling pathways (101, 102).