Disease phenotype of a ferret CFTR-knockout model of cystic fibrosis

Abstract

Cystic fibrosis (CF) is a recessive disease that affects multiple organs. It is caused by mutations in CFTR. Animal modeling of this disease has been challenging, with species-and strain-specific differences in organ biology and CFTR function influencing the emergence of disease pathology. Here, we report the phenotype of a CFTR-knockout ferret model of CF. Neonatal CFTR-knockout ferrets demonstrated many of the characteristics of human CF disease, including defective airway chloride transport and submucosal gland fluid secretion; variably penetrant meconium ileus (MI); pancreatic, liver, and vas deferens disease; and a predisposition to lung infection in the early postnatal period. Severe malabsorption by the gastrointestinal (GI) tract was the primary cause of death in CFTR-knockout kits that escaped MI. Elevated liver function tests in CFTR-knockout kits were corrected by oral administration of ursodeoxycholic acid, and the addition of an oral proton-pump inhibitor improved weight gain and survival. To overcome the limitations imposed by the severe intestinal phenotype, we cloned 4 gut-corrected transgenic CFTR-knockout kits that expressed ferret CFTR specifically in the intestine. One clone passed feces normally and demonstrated no detectable ferret CFTR expression in the lung or liver. The animals described in this study are likely to be useful tools for dissecting CF disease pathogenesis and developing treatments.

Generation of multiciliated cells in functional airway epithelia from human induced pluripotent stem cells

“…There are significant differences in mouse-lung morphology and disease development. While providing some very important information, mouse models of diseases such as asthma and cystic fibrosis do not accurately represent the human disease (61,62). The aforementioned reasons highlight the importance and necessity for a pliable human model of lung disease.…”

Pseudomonas aeruginosa triggers CFTR-mediated airway surface liquid secretion in swine trachea

“…The failure to clear bacteria likely results from abnormal airway surface liquid (ASL) secretion and properties (6)(7)(8)(9)(10). The ASL consists of a layer of mucus that traps inhaled particles and a periciliary liquid layer that keeps the mucus an optimum distance from the underlying epithelia to maximize ciliary mobility (10,11).…”

“…The airway liquid produced by CFTR −/− swine has weaker bactericidal properties compared with that produced by WT littermates, owing to abnormal pH (3,4). In addition, human CF airways, 1-d-old CF piglets, newborn CFTR −/− ferrets, and CFTR −/− mice fail to respond to stimulatory signals that normally elicit strong ASL secretion (6)(7)(8)(9). Consequently, it has been proposed that abnormal secretion of fluid and mucin in response to bacterial infection may contribute to the pathogenesis of CF lung disease (7)(8)(9)(10)(12)(13)(14)(15); however, the central questions of whether bacteria trigger ASL secretion in the airways, and the role of CFTR in such a process, have not been explored previously, owing to the lack of a suitable experimental technique.…”

Bacterial host interactions in cystic fibrosis

“…Mouse models have been limited as CF-mice generally exhibit a normal lung physiology without mucous plug obstruction. More recently developed CF-pig and CF-ferret models demonstrated mucous gland secretions that resemble those of human CF [59,60]. The lungs of newborn CF-piglets showed evidence of airway obstruction and reduced eradication of instilled bacteria [61].…”

“…The lungs of newborn CF-piglets showed evidence of airway obstruction and reduced eradication of instilled bacteria [61]. CF-ferrets showed a higher abundance of bacteria in two-day old animals, but this difference was not maintained in animals that died after one week [59]. Analysis of these models continues and it may be several years before they become effective tools for host-pathogen interaction studies.…”