Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Dysfunction in Human Diseases: Molecular Mechanisms and Pathophysiological Implications

Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) dysfunction is increasingly recognized as a key contributor to a broad spectrum of human diseases beyond classical cystic fibrosis (CF). CFTR is a cAMP-regulated chloride and bicarbonate ion channel expressed in both epithelial and non-epithelial tissues, where it regulates ion homeostasis, mucosal hydration, and cellular signaling. Both inherited CFTR mutations and acquired dysfunction resulting from environmental or inflammatory factors can disrupt these physiological processes and drive disease progression. Current evidence linking CFTR dysregulation to respiratory diseases, such as cystic fibrosis, chronic obstructive pulmonary disease (COPD), asthma, and HIV-associated airway disease, as well as cardiovascular, renal, neurological diseases, and cancer, is comprehensively discussed. Mechanistically, impaired CFTR function promotes oxidative stress, chronic inflammation, epithelial barrier dysfunction, altered mucociliary clearance, and dysregulation of signaling pathways, including NF-κB, TGF-β, PI3K/Akt, MAPK, and Wnt/β-catenin. In the context of HIV infection and cigarette smoke exposure, CFTR suppression is mediated in part by TGF-β signaling and miRNA-dependent mechanisms, resulting in compromised airway defense and increased susceptibility to pulmonary complications. Recent studies further demonstrate that CFTR dysregulation alters the expression of genes involved in fibrosis, inflammation, angiogenesis, and epithelial–mesenchymal transition (EMT). Notably, CFTR may act as either a tumor suppressor or a context-dependent oncogene, depending on tissue type and signaling milieu, highlighting its complex role in cancer biology. Advances in CFTR-targeted therapies, including potentiators, correctors, gene therapy, and combination approaches, have markedly improved outcomes in CF and may offer therapeutic potential for diseases associated with acquired CFTR dysfunction. We summarize the systemic consequences of CFTR dysregulation and the need for further mechanistic and translational research to clarify its role across diverse human diseases.